ALBERT

Description: Interleaved DC-DC converter topologies are gaining popularity for their use as an interface between photovoltaic (PV) source and load. In this paper, a family of coupled inductor (CI) based novel soft switched interleaved DC-DC converter topologies has been proposed to be used for PV application. The topology has been developed from the interleaved stage so as to reduce the input current ripple. The CI stage has been introduced to enhance the power handling capability of the converter. In addition, diode-capacitor multiplier (DCM) cells are connected to obtain higher voltage gain. Since voltage gain extension is obtained through DCM cells and the turns-ratio of the CI, the voltage stress on the main power switches is only a fraction of the output voltage. Further, the diodes present in each DCM cell need to withstand only a low reverse voltage. To enhance the operating power conversion efficiency, the power switches are turned ON under zero voltage switching (ZVS) condition. Experimental results obtained from a 20V-360V, 200W prototype converter validate the operating principle and the advantageous features of the developed topology.

Description: In order to obtain a high current efficiency a photovoltaic generator PV, it has been necessary to recuperate the heat dissipated by combination a PV to a thermal heating system. The heat exchanger is under the PV, thus cooling the cells back face. Such a system therefore improves the efficiency of the PV module while extracting useful heat calories heating. In this paper, a 3D model of a new PVT collector has been implemented using the Comsol environment. A (FEM) approach is used for the analysis of the thermal and electrical behavior of new absorber integrated for the PVT collector which has as an advantage of a simple realization and to use a material of galvanised steel for it low cost  compared to other configurations of PV/T hybrid collectors. Some results are presented the temperature of the PVT collector decreases with the increasing flow rate, For a flow rate of about 0.0016 kg/s and irradiation of 1000W/m² and ambient temperature equal to 20.15 °C, the temperature reaches a value equal to 55.96°C. The influence of mass flow rate in the PVT collector demonstrate that the PV cell temperature decreases with the increasing mass flow rate and the increases  until the flow rate reaches about 0.0256 m/s; it reaches a value equal to 23.845 °C and electrical power equal to 59.434 after these values will be maintained at a relatively constants values.

Description: Ecological system is being affected adversely by the use of diesel engines which causes harmful emissions. Alternative sources are being found  to sort out this problem. Biodiesel is one of the alternative source.  Nowadays, there is a focus on the non-edible oils to use it as biodiesel because of its capability to be available on waste lands. Karanja is one of the non-edible oil, which may be  preferred to be used as biodiesel because of its certain advantages on diesel engine comparatively. This experimental study was  aimed to find out performance characteristics and smoke emission with 10%, 20% and 30% biodiesel blend with diesel at varying loads (brake power) of 0.5 to 3.5 kW at a constant speed of 1500 rpm. Brake thermal efficiency, brake specific energy consumption, exhaust gas temperature, mechanical efficiency, volumetric efficiency, air fuel ratio and smoke opacity  of biodiesel blended fuel were evaluated and  compared with diesel and it has been  found satisfactory. Brake thermal efficiency of 20% biodiesel blend fuel was found to be slightly higher  than that of diesel with reduced smoke emissions.  Brake thermal efficiency of B20 and diesel was found to be 29.04% and 29% respectively at 3.5 kW brake power. On the basis of experimental study, the B20 Karanja biodiesel blend is found more useful among all tested fuels in terms of brake thermal efficiency. Smoke opacity was also found to be reduced with Karanja biodiesel blends. Hence Karanja biodiesel is proved to be an environmentally friendly alternative to diesel.

Description: The partial shading is one of the major problems that exist in the photovoltaic farm installations. This is due to the presence of multi peaks in the power curves characteristics where the conventional methods of maximum power point tracking were not able to solve the problem. To overcome this shortcoming, in the present contribution we suggest a simulator based on a tracker algorithm which is able  to track the global maximum GP in three cases , namely uniform irradiance ,sudden irradiance , and the partial shade conditions. The obtained results are compared to the data reported in the literature and showed good agreement. Thus, our simulator has been extended to include not only uniform irradiance case, but also the other mentioned cases.

Description: This paper deals with an adaptive maximum power point tracking (MPPT) of photovoltaic systems controlled by a second order sliding mode. The main goal of the proposed work is to track the maximum power point (MPP) using adapted algorithm. In addition, the use of the second order sliding mode control (SOSMC) can reduce the chattering phenomenon and ensure high transient response for a wide range of desired current or voltage under parameter variations. The proposed control is tested under different operating conditions. All results confirm the effectiveness of our proposed algorithm.

Description: As the power level of a power electronic converter is limited due to several factors and the increase in current causes an increase in stress on switching devices. Besides, the diode reverse recovery current and parasitic resonance current become greater than the main switch can handle, and hence, the size of the boost inductor should be increased to avoid saturation and overheating problems. In order to advance the power level significantly the methods, including device paralleling, module paralleling and interleaving are widely utilized. For some applications, boost stages are designed modularly such that the converter stages can be connected in parallel to meet the increasing power requirement. This method is preferable as it is easy to increase thepower rating by simply stacking converters with increased redundancy. The drawbacks of the method are; it relatively costs high, large volume covered, and cooling difficulties. Furthermore, to provide equal sharing of input current among the converters, additional circuitry should be utilized and the currents of individual converters do not return properly, current of one module can circulate through other module and some unexpected failures may occur. This paper reviews the ripple input current and output voltage of two and three phase and investigates the Performance of four phase IBC.

Description: One of the prospects for the development of application of gas turbine engines in the decentralized energy system is to use a microturbine units operating on biofuel. Authors in this paper propose a new method of designing of microturbines and consider some aspects and special features in the design of micro-turbines.

Description: This study involves a performance  analysis between solar photovoltaic (SPV) operated vapour compression and vapour absorption refrigeration systems. For the purpose of comparison, two refrigerators working on different refrigeration cycles (compression and absorption) have been selected. The temperature and energy consumption of both units were recorded by using various parameters. The results show that though the vapour absorption refrigerator takes more time to decrease the temperature of the cabinet in comparison to the vapour compression refrigerator yet it consumes less power. The vapour absorption system is especially useful in rural areas having no or less frequent power supply where we want to preserve drugs and food items because it can maintain a constant low temperature between 6-10°C if delivered on the same temperature . The initial capital cost of the absorption refrigeration system is also less than compression system.

Description: In this paper, a power control strategy for the brushless doubly fed reluctance generator (BDFRG) based variable-speed wind turbine system is proposed. The proposed control strategy covers all system operational regions including: maximum power point tracking (MPPT) region, constant speed region, and constant power region; whereas, the studies in the literature for the BDFRG wind turbine system are only limited to the MPPT region. For capturing maximum power from the wind in the MPPT region, a turbine power feedback based MPPT, which is a method with fast dynamic response, is used. In the constant speed region, the BDFRG speed is kept constant, and for high wind velocities in constant power region, the controller decreases the BDFRG speed to prevent the increase of the turbine power more than its rated value. In addition, a turbine power observer is proposed to obtain turbine power. The BDFRG wind turbine system model based their dynamic equations, which explained in the paper, is simulated in MATLAB/Simulink software and the performance of the proposed control strategy is studied. The simulation results verify the effectiveness of the proposed control strategy in all three operational regions as well as the acceptable performance of the turbine power observer.

Description: Inclusion of renewable generation in the existing network is necessary due to the increase in raw material cost for generating electricity and growing demand. Optimal power flow incorporating wind generation is solved using Particle swarm optimization (PSO) in this paper. Weibull distribution function is used for modelling the intermittent nature of wind farm and then it is incorporated in the existing power system network. A direct cost function of the wind power purchased is presented in the paper. Cases without and with wind power are solved using PSO due to its ability in solving the non linear problems. The analysis is carried out on IEEE 30 bus test system and the obtained results are compared with the few existing methods. From the results it can be inferred that this method provides enhanced results.

Description: The purpose of this study is to develop an all in one and maintenance free power-generating facility for river, ocean or tidal flow. A swivel mile with turbine, power generator, and auxiliary systems are installed in the same axial line and under water level. This architecture can reduce the mechanical loss and increase the efficiency of electric power generation. The facility can be easily lifted up on water level for its maintenance. To realize the all in one architecture, an excellent shaft seal is required. The shaft seal can prevent ingress of water into the facility. The frictional torque of the shaft seal should also be minimized to increase the efficiency of electric power generation. A diameter of the power generator, installed into the facility, should be minimized hydrodynamic resistance from its architecture. Barnacles and algae growth onto the surface of facility reduce the generating efficiency and increase the hydrodynamic resistance. A new technology is adopted from a coating of hydrated material.

Description: Undoped and Na-doped CuInS 2 powder has been synthetized by direct fusion of precursor elements. We have deposited those two materials in thin films on glass substrate and on copper layer by vaccum thermal evaporation method followed by an annealing in air atmosphere at 250°C and 450°C. We have investigated their structural, optical and electrical properties that show good results for photovoltaic applications. The undoped CuInS 2 layer exhibit an n-type conductivity whereas Na-doped CuInS 2 is p-type both on glass and on copper layer. X-ray analyses of the as deposited samples show amorphous structures. The annealed samples in air showed a crystalized CuInS 2 layer with a major peak of the (112) chalcopyrite phase with the presence of CuO and In 2 S 3 impurity phases for the 450° annealed. Optical gap of both undoped and Na-doped CuInS 2 where between 1.4 and 1.6 eV, that is close to the optimal gap value 1.5 eV of the CuInS 2 suitable for a good absorption of solar spectrum. Electrical characterizations showed good ohmic contacts with low Schottky barrier height, and good ideality factor of respectively (0.75 eV, 1.37) for undoped and (0.66 eV, 1.27) for Na-doped CuInS 2 /Cu contacts. Also, we observed a low value of series resistance 3.51 and 1.75 Ohms respectively that suppose a good current flow in the contact

Description: Multiphase buck topology offers smaller ripple current and lower component ratings. This, however, compromises unbalanced output current between each phase of an inductor which leads to over-current and inductor saturation issues. Often when discussing the linear control schemes, it involves the use of superposition theorem to understand the system’s response. However, the limitation of superposition theorem in this application is that it assumes the circuit to be completely linear. For components with nonlinear behaviour such as power switches and diodes, the analytical results may not be accurate resulting to unexpected behaviour as the algorithm is implemented on a real system. Hence, the use of a more advanced control scheme is necessary to improve a system with a non-linear characteristic. This paper proposes a current limit control (CLC) consists of MPC for inner loop control and PID for outer loop control for phase current balancing in a four-phase buck converter. The controller is designed to achieve balanced current for each phase with acceptable response time. The proposed system is designed using MATLAB/Simulink simulation software and verified by a laboratory prototype with aTMS320F28335 as the main controller. Simulation and experimental results are provided to validate the system performance.

Description: Energy management is proposed in order to make a best use of the renewable generation and storage units. The management strategy should guarantee a permanent production of electricity in an isolated chalet for an off-grid system supplied by photovoltaic panels and batteries. The chalet composed by three types of load: priority loads where they will be supplied all time, secondary load where it may be supplied only in case of energy availability and finally the extra-loads will be supplied during a definite time. This paper presents a model for isolated system behavior in terms of control powers exchanged between sources power and loads demand. The model is based on Timed Hybrid Petri Net formalism. Therefore, an iterative algorithm for power flow management satisfies requirement of each type of load based on the photovoltaic panels production and the storage units. Obtained results show that the proposed strategy satisfies the priority loads during the whole day, covers the secondary load energy and gives user liberty to exploit the extra-loads as possible.

Description: The aim of this paper is to propose a neural network based reference modified PID control which has a simple duration design method for transient characteristics improvement of digitally controlled dc-dc converters. In renewable energy network systems, various types of dc-dc converters are widely used for power conversion and such converters require a superior control method for a stable operation. Especially, transient characteristics should be improved since they heavily affect the stability of the system. For such purposes, designing of conventional control methods becomes a difficult task since the optimization of control parameters needs complicated analysis and it is affected from variations of circuit components of converters. Therefore, simple and easy design of control is widely required for a stable operation of power converters. The neural network can provide a suitable control methodology for such situation since it treats the plant as a black box and it can realize a non-linear control based on training of the input-output relation without complicated modelling and analysis. On the other hand, the neural network based method has a disadvantage caused from the fact that the neural network is trained with data obtained in advance and an overcompensation phenomenon occurs in the transient response. In this paper, the neural network control is adopted to control the dc-dc converter in coordination with a conventional PID control. The neural network predicts the output voltage of the converter and the reference value in the PID control is modified with the predictions to reduce the error of the output voltage. To avoid overcompensation, a simple duration design for the neural network control is also provided to improve the transient response effectively. From prototype testing in simulation and experiment, it is revealed that the proposed method contributes to obtain a superior transient performance compared with the conventional PID control.

Description: The penetration of wind generation in modern day energy system is increasing day by day. Wind is a variable parameter in nature which has a significant effect on the generator behavior. Since most of the existing installed generators are self-excited induction generators (SEIG), they have a negative effect on the system during varying wind speeds and varying load. The primary parameter found responsible is reactive power requirement for self-excitation. So, instead of replacing these generator sets, an alternative reactive power source connected in coordination to machine can well handle these situations. In this context a new promising method of stabilizing SEIG with doubly fed generator (DFIG) is developed in this paper. A new technique of representing DFIG in terms of its equivalent capacitance is developed, to study reactive its power handling capabilities. The potential of the developed model in stabilizing the SEIG during varying wind speeds and varying load conditions is simulated and analyzed. The developed model is independent of complex d-q axis model and simple to understand the behavior of machine. The result shows that this method of supplying reactive power requirement of SEIG is satisfactory in maintaining voltage build up of SEIG. The results obtained are well validated by power balance.

Description: This paper aims the integrationof photo voltaic array and battery in a micro grid and management of energy happening in the grid. The regulation of battery depending on the requisite of load i.e., battery hold, charge and discharge actions using a bi-directional DC-DC converter has been proposed. The usage of a simple boost converter and interleaved boost converter with MPPT control, two-level inverter and three-level NPC inverter has been compared for various situations like PV delivering supply to the load and charging battery, only PV system delivering supply to the load, only battery delivering supply to the load and PV-battery both delivering supply to  the load. Output factors like power, voltage and current are analyzed and plotted for all the situations. The proposed micro grid energy management system is simulated under MATLAB/Simulink environment

Description: A dye sensitized solar cell (DSSC) was fabricated using nanoporous TiO 2  film and dye extracted from Kenaf Hibiscus (Hibiscus Cannabinus) flower. To the best of our knowledge, dye extracted from kenaf hibiscus has not been used as photosensitizer for DSSC application till date. The TiO 2­  film was fabricated on ITO coated glass and further absorbed in  dye which acted as photo anode and another ITO coated glass with a platinum coating was served as counter electrode (cathode). An optimal blend of acetonitrile (solvent) (50-100%), 1,3-dimethylimidazolium iodide (10-25%), iodine (2.5-10%) and lithium iodide, pyridine derivative and thiocyanate was used as electrolytes in the DSSC. The different structural, optical and electrical characteristics were measured. The DSSC showed a maximum conversion efficiency of 2.87 %.

Description: Rotary machines have many rotating structures necessity design-optimization. Their structure motions are controlled at low-frequency by rigidity, at high-frequency by inertia and at-resonance level by damping. Using modal model, dynamic design of the structure developed can be predicted, analyzed and improved. Recently, H-Darrieus wind turbine has (HDWT) received considerable attention due to its inherent structural characteristics. This machine intends a promising design of renewable energy conversion system in urban areas and isolates sites. Though, the system suffers of several dynamic problems caused by geometry, centrifugal and aerodynamic cyclic loadings. Present paper investigated dynamic design-optimization of a three-bladed (HDWT) based on its natural structural parameters using 3D CAD, FEA using SolidWorks modeling and simulation. From simulation result obtained, the first five natural frequencies of the system, corresponding mass participate, damping factor, and mode shapes are predicted and analyzed. The static and dynamic stability and reliability of the system are shown since security factor and all quality indicators  tested, amplification factors, and resonant amplitude ratios are consistent according to the recommendations of structure dynamics standards. Furthermore, critical operating conditions of wind turbine under forcing excitations of the wind speeds at various regimes are also treated and assessed.

Description: Dye sensitized solar cells (DSSCs) based on natural dyes extracted from dried Hibiscus Sabdariffa and Rosa Damascena flowers were fabricated. The extracts were characterized by UV-Vis absorption spectroscopy. The TiO 2 nanopowder paste was spread on FTO layers to form a thin layer. Three processes were conducted to improve the cell efficiency such as pre- and post-treatments of TiO 2 and FTO layers with three acids and changing the pH of the extract solutions. The conversion efficiency of the DSSCs sensitized with Hibiscus Sabdariffa enhanced by 107% and 114% when treating the FTO sheets for 5 min with H 3 PO 4 and HCl, respectively. It was observed that when HCl acid was used to adjust the pH value of the dye solution of Rosa Damascena to 2.0, the efficiency of the DSSC was enhanced by about 180%.

Description: Global environmental concerns and gradual escalation of fuel cost linked with conventional energy sources encouraged the use of renewable energy in electric power supply sector greatly. India is blessed with great environmental wealth of solar energy due to its favorable location (40ºS to 40ºN). This research work explores the viability of great solar potential of 14 Indian geographical locations by estimating Global Solar Radiation(GSR) for four summer months using Artificial Neural Network (ANN). Initially, eight parameters are chosen as input data set for ANN from a number of environmental factors influencing GSR,based on their natural dependence on it. But, less correlated inputs as training data set for ANN results lead to more sensitive outputs.So, lately, inputs to the ANN are extracted based on Spearman rank-correlation coefficient, where only positively correlated input factors are considered as the input data set for the ANN to enhance its performance.Spearman rank-correlation coefficient describes the extent of correlation between two variables using a monotonic function by utilizing rank-order of the data regardless of distribution between two data sets.  This makes it suitable not only for discrete and continuous variables but also ordinal variables (data sets including inconsistent values).A multi layered, feed forward, standard ANN model with one hidden layer and five hidden neurons corresponding to least mean square error is considered among various ANN models with different training algorithms, hidden layers and neurons, for the prediction of GSR. It is found that correlation based ANN predominatessimple ANN.

Description: The determination of the value of investment projects must take into account the risk-return trade-off present in the market. The fiscal, economic and monetary policies of the various international organizations have an impact upon the market and subsequently on the perception of risk. This study analyses the trend of one of the parameters for risk assessment in valuation processes, between 2011 to 2013, for the specific sector of small and medium-sized enterprises involved in generating electrical energy from alternative sources in Spain

Description: This paper develops an efficient solution towards the prognostics of industrial PEMFC. It involves employment of an efficient multi-energetic model suited for diagnostics and prognostics, developed in Bond Graph framework. The Electrical-Electrochemical (EE) part constitutes the main focus for the problem of prognostics, wherein deviation of the global resistance and limiting current inspires a statistical linear degradation model (DM), under constant current load conditions. The benefits of Particle Filters (PF) is integrated with the BG model derived Analytical Redundancy Relations (ARRs), for prognostics of the electrical-electrochemical (EE) part. The prognostic problem is formulated as the joint state-parameter estimation problem in Particle Filter framework. Using PF algorithms, in probabilistic terms,  estimation of State of Health (SOH) is obtained along with the estimation of the associated parameter that influences the rate of degradation. A simplified variance adaptation scheme is employed to ameliorate the accuracy of remaining useful life (RUL) predictions.  Influence of variance adaptation on SOH estimation as well as RUL prediction is assessed.  It is shown that a proportional type of variance control leads to better accuracy in RUL predictions accompanied with precise confidence bounds. As the degradation data is obtained from a real industrial PEMFC, the economic viability of this approach for prognostics of PEMFC is significantly high.

Description: In recent years, the renewable energy system requires the modeling language based control and the high-performance CPU. As for CPU, the improvement of the CPU performance reaches its limitation caused from its clock frequency. Therefore, the multi-core and the virtualization are mainstream strategies for its improvement and such mechanisms have some issues including complicated algorithm of controller and inheritance of design on CPU architecture generation. For such reasons, Field Programmable Gate Array (FPGA) is expected to replace the role of CPU since it has several advantages such as long period supply, inheritance and power-saving. It is applied to the small machinery control so far, and there are few researches to apply it to the power plant control. For such purpose, a flexible control with the modeling language like CPU and on-line modification of the control logics are necessary. In this paper, to fulfill such requirements on the control system for the infrastructure like the power system, a new FPGA based controller named "green controller" is proposed. An architecture to realize it and required conditions based on FPGA are clarified. Furthermore, performance and FPGA resource usage are measured in the experiment with the proposed architecture for evaluation.

Description: An advanced modulation technique-based harmonic control approach, known as hysteresis inverter control, in an inverter-connected renewable energy source (RES)-based islanded microgrid system is proposed in this paper. An LC low-pass filter is also used with the feedback control scheme in order to ascertain the control of harmonics in a desired manner. With a view to understanding both the fundamental and harmonic components of the output wave-shapes, fast fourier transform (FFT) analysis is carried out in this paper. MATLAB software is used to simulate the inverter performance within a microgrid system with the proposed feedback control. It has been found that system wave-shapes are sinusoidal and the total harmonic distortion (THD) is less than 0.5%, meaning the proposed method is effective.

Description: The country's industrial development has led to increment in consumption of energy. Thus, energy saving is substantial in developed countries. Due to implement of cement in industry construction, authentic manufacturing method is essential. Cement is considered as high consumed source for industry which requires high productivity. On the other hand, imminent depletion of fossil resources, leads to utilization of alternative fuels. In this paper, we explore the possibility of alternative refuse-derived fuel (RDF) from Rasht city for Lowshan Cement Factory. The best choice of RDF for Lowshan cement factory is Fluff RDF. Considering the amount and the type of waste, 168 tons per day Fluff RDF has been calculated. It was determined that the use of RDF as an alternative fuel could raise heating value and lower production costs. 168 tons of RDF with heating value of 17790Kj/kg would be 21.2% of the energy needed to supply the cement factory. Exergy efficiency of the reaction is increased by applying RDF. By increasing the amount of paper in RDF, exergy efficiency increment rate is more than other material contained in RDF.

Description: The increasing cost of energy associated with higher production of polluting gases is a major threat to the whole world. It is a high time to find out alternative pollution free energy resources. Fuel cell is one such electrochemical energy producing unit to produce clean electrical energy. The major challenge in the development of fuel cell is to produce inexpensive, high energetic electro catalytic electrode materials. Present investigation deals with electrochemical characterization of the synthesized Ni-Co-Fe, MnO 2 -C, ZnO-Al 2 O 3 and Ni-CeO 2 -Cu for electrochemical oxidation of fuels like methanol, ethanol, and glucose. It has been found through studies of Polarization test, Cyclic Voltammetry, Chronoamperometry that all these electrodes performed very well with low polarization resistance, high exchange current density and delivers maximum current from the fuel oxidation. But the electrode Ni-CeO 2 has outperformed all other materials including Pt. The electro-synthesis of these materials has been performed at an optimum current density, potential, electrolyte chemistry by a series of experiments. The materials were characterized by XRD which confirms the constituent’s presence of metals and metal oxides. The SEM studies exhibits grain refinement of Ni-CeO 2 due to CeO 2 addition. The fact confirms the fine grain 3D structure account for fast electrochemical reaction of the fuel.

Description: The performance of a four stroke, single cylinder, direct injection CI engine is evaluated having fuel as neat jatropha-diesel blend in proportion 2:1 on a volume basis. The experimentations were conducted to test engine performance and emission characteristics at throttle settings of 25%, 50%, 75% and 100% and variable loads covering under load to overloading of engine operation. The effect of jatropha blend on engine brake power, brake thermal efficiency and specific fuel consumption were observed at different loads and throttle openings along with exhaust emissions and exhaust gas temperatures. Compared to jatropha blend diesel provides better performance for entire operating range (of loads and throttle openings) but effect of varying load /throttle settings on performance characteristics are of similar nature. The jatropha blend produces lower hydrocarbon and NO x emission, highlights the positive aspects of combustion and the allowance of higher effective compression ratio of the blend.

Description: In this paper are presented experimental results obtained by equipping vertical axis wind turbine with electric generator. In the experiments were tested two ways of equipping the turbines, first with a generator connected directly to the rotor shaft and second with a generator, with less power, connected to the rotor shaft through a toothed wheel gear. To achieve these tests were used three types of vertical axis wind turbines, i.e. a single stage Savonius rotor, a double stage Savonius rotor and a single stage type ‘Z’ Savonius rotor.  After tests it was observed that the best solution for equipping wind turbines with electric generator is the one with the connection to the rotor shaft through a toothed wheel gear. In this case, even if the rotor speed values are closer to the first case, the voltage is much higher. At wind speed of 3 and 4 m/s, the single stage Savonius rotor generates more power than the other two. At wind speed of 5 m/s, the greatest amount of power was generated with the double stage Savonius rotor. Following these tests, it can be concluded that, in order to ensure the highest energy production, is recommended to use vertical axis wind turbine with double stage

Description: With more than 4000 hours/year sunshine duration, Algeria is blessed by a perfect geographic location which makes it suitable for solar domain applied studies as solution for the future of the green renewable energies. Unfortunately, despite the great support given by the state and mines minister to encourage the Algerian population to integrate solar energy especially for the southern regions, The survey shows that people hesitates the integration of this type of sources looking the increases of the prices for these systems; mainly the storage part using batteries cell storage. Even the new technology based on lithium ion batteries that gives more storage capacity and more performances; remains out of reach for the majority of citizens which is the case in the different parts of the world. With collaboration between LGEC laboratories within a full support from the ministry of mines under a Basic deliver although precise data by CDER (National Center for renewable energies) and URAER (the applied research unit for renewable energies). Through this article, the researchers propose a thorough study of a whole solar pumped hydro energy storage plant system for a consumption model on the wilaya of Ghardaia in the southern of Algeria.

Description: In this paper, we have studied and analyzed the shading effect on solar photo voltaic (SPV) modules connected in series using four 75 W SPV modules for three different shading conditions: (1) one module is fully shaded, (2) two modules are fully shaded and (3) three modules are fully shaded. The performance of the modules which decreased due to shading effect are improved in each case using bypass diodes connected in parallel with each of the modules. This analysis is done by using the simulation model in PSCAD and an outdoor experiment is also performed to validate the simulation results for the same configurations. An improvement in open circuit voltage (V oc ), short circuit current (I sc ), maximum power (P max ) and power efficiency are observed when bypass diodes are used. During an outdoor experiment when one panel is shaded the power efficiencies are 17.96 % and 12.79 % with and without bypass diodes respectively. In case of two modules are shaded these values are 14.50 % and 9.63 % respectively. When three modules are shaded the power efficiency is 3.59 % in case of without bypass diode, which is increased to 6.87 % with bypass diodes.

Description: The Greenhouse gas (GHG) emissions turns out to be one of the most important factor contributing to global warming significantly. Literature revealed that reservoirs too can be an important source of emissions, especially in tropical areas. A lot of efforts have undergone in determining the GHG from reservoirs, however, due to various uncertainties like lack of standardized measurement tools and techniques, till date the determination has been little difficult. Some of the international organization like United Nations Educational, Scientific, and Cultural Organization (UNESCO), International Energy Agency (IHA), and International Hydropower Association (IEA) has been making a lot of effort to know the contribution that reservoirs make in GHG emissions. The key objective of this paper is to find policy and challenges at different scales that could help to address the GHG emissions from reservoirs and its impact on climate change. 

Description: Performance and emission characteristics of diesel engine were reviewed in this work. This study was conducted by revising works that were conceded out using biodiesel prepared from the raw oils of: palm, moringa, Jatropha and diesel fuel. In this review study we consider only 20% of each biodiesel (described as MB 20 , PB 20 , and JB 20 ) was tested in diesel engine, given that open literature indicates the possible use of biodiesel of up to 20% in a diesel engine without any engine modification. All biodiesel fuel samples reduce brake power (BP) and increase brake specific fuel consumption (BSFC) than diesel. Diesel engine emission results indicated that blended fuel reduces the average carbon monoxide (CO) and hydrocarbons (HC) emissions except nitric oxides (NO x ) emissions than diesel fuel. B 20 blend of biodiesel is a suitable source for alternative fuel, with ecological welfares. Among the biodiesel blended fuel, Palm biodiesel showed better performance and minimum emission than jatropha and moringa biodiesel fuel. Although PB 20 showed better performance, but performance of MB 20 biodiesel blend is comparable with other fuels. Correspondingly, MB 20 can be used in a diesel engine without any engine modification.

Description: – Many modifications have been made on c onventional Savonius wind turbine’s rotor blades have been made to improve the performances. The rotor blade modification in this research is a blade combination where the circle-shaped conventional model is combined with the one of a concave elliptical model. The combined blade will not affect the simplicity of construction and cost of manufacture of turbine rotors.  The aim is to analyze the influence of the blade combination towards the performance of Savonius turbine. The research includes experimental method using open-jet-type wind tunnel of rotor’s prototype with three different blade models of the same dimension. The experiment shows, there are influences of the modification of the rotor blade to the performances of the turbine. The combined blade improves the performances of the power coefficient maximum (Cp max ) up to 11 % compared to the conventional blade at the tip speed ratio (TSR) of 0.79 Keywords - Savonius turbine, combined blade, experimental, performance

Description: This paper presents modeling and control of Photovoltaic/fuel cell/supercapacitor hybrid power system for stand-alone applications. The hybrid power system uses solar PV array and fuel cell as the main sources. These sources share their power effectively to meet the load demand. The supercapacitor bank is used to supply or absorb load transients. The main control system comprises of MPPT controller for PV system, a DC-DC boost converter with controller for fuel cell system for power management and inverter controller to regulate voltage and frequency. The stand-alone hybrid system aims to provide quality supply to consumers with a constant voltage and frequency. The modeling and control strategies of the hybrid system are realized in Matlab/Simulink.

Description: Nanotechnology plays a major role in heat transfer related problems. This study evaluates the effect of nanofluid as a working fluid on parabolic solar collector’s overall efficiency through both experimental and CFD analysis. α-Al 2 O 3 nanoparticle of 20 nm average size is used for the preparation of  Al 2 O 3 -H 2 O (DI)  nanofluid of four different volumetric concentrations of 0.05%, 0.75%, 0.1% and 0.125% respectively. Working fluid is made to flow at three different volume flow rates (30 LPH, 50 LPH and 80 LPH). ANSYS FLUENT 14.5 is used for carrying out CFD simulation, where solar flux is modelled through solar load cell and solar ray tracing. It has been observed that, there is improvement in instantaneous efficiency, thermal efficiency and in overall efficiency, when water is replaced by Al 2 O 3 -H 2 O (DI) nanofluid and also with corresponding increase in the mass flow rate of working fluid. An improvement of about 9.31%, 11.87%, and 13.98% in the collector’s overall efficiency is seen, when water is replaced by 0.125% vol. conc. Al 2 O 3 -H 2 O (DI) nanofluid at a flow rates of 30 LPH, 50 LPH and 80 LPH respectively. Also, both experimental and CFD analysis results are in close agreement with a difference of 8%.

Description: Bangladesh is one of the largest populated countries of the world, where more than one third of the population is living without electricity. Being a developing country, the demand of electricity is increasing tremendously.  Meanwhile, fossil fuel based electricity generation plants are lagging behind to supply the rising demand and the fossil fuel sources are very limited. As an alternative, renewable energy based systems are becoming popular in Bangladesh, particularly solar, wind and hydro based systems, which are being set up in different sizes and configurations. This paper presents feasibility analysis of renewable energy based hybrid system for the village of Kuakata, in the southern area of Bangladesh. The system is designed based on the resources available at the location. The sources considered in the analysis are solar PV, wind, diesel generator and battery backup system. HOMER simulation model has been developed for simulating the system with real weather data and nominal load profile. The cost of the system is determined based on the real market price of the components. Sensitivity analysis has also been carried out on the best suitable system to prove the system sustainability in the future. For sensitivity analysis, the change in load and change in rate of interest has been considered. Based on the factors such as initial cost, replacement cost, operating cost, total net present cost (TNPC), cost of energy (COE) and exhaust gas emission, the results show that PV-Wind-Battery based system is a feasible solution for the situation. The optimum system has the initial cost of 126,586 $, replacement cost of $ 125,280, operating cost of 5007 $/year, TNPC of 224,345 $ and COE of 0.161 $/kWh with no exhaust gas emission. Foremost, the emission is zero, which means it is green energy system.

Description: The aim of the paper is to enhance the performance of membrane supported water desalination techniques to reduce the consumption of energy by employing solar energy. Development of the pilot plant in the laboratory has been carried out to desalinate the brackish water using PV collector. Experimental study was carried out and report the effect of temperature, time and flow rate on permeates flux. Results show that permeates flux increases with increase in temperature. Also the analysis of the well water has been performed by various techniques and reported. It was found that vacuum membrane distillation using solar energy provide better quality of water in comparison to other treatment techniques. This study provides an idea for the application of renewable energy in the field of desalination of water on a small scale.

Description: Global warming has become a threat of our time. It poses challenges to the existence of all biota on this earth and has made a clear impact on the level of energy and water consumption. No doubt, increase in the ambient temperature increases indoor and outdoor temperature level of the buildings which catalyzes the use of energy and cost intensive mechanical air-conditioning systems. Green roof tops belong to such an idea for cutting down the energy consumption and enhancing the comfort level of commercial and residential buildings. This paper investigated the impact of green roof on thermal performance and cooling potential in Indian climate.  It was observed experimentally that compared to the exposed roof, the room air and interior surface temperature of the green roof were reduced by a maximum of 17% and 22% respectively. Heat flux studies show that not only the peaks are lower but also the diurnal heat fluctuation through the green roof assembly is lower than that of the conventional roof in the case of heat in-leak. Further, a thermal lag of around 2 to 3 hours has been observed. The simulated model developed in this study has been closely replicated by the experimental data, thereby efficacy of the model is demonstrated unequivocally.

Description: The emergence of the Distributed Generation (DG) units along with their application in the distribution system level has led to the establishment of microgrids. microgrids are a part of the distribution network in which, in addition to the loads, there are microsources operating in two modes, i.e. grid-connected mode and island AKA standalone mode. In the grid-connected mode, the load is supplied through local DG units, and if necessary, power is exchanged with the upstream grid, concerned as well.  Considering the development of DG units technology in recent years which in turn, has led to the expansion of microgrid concept  , microgrid planning meaning determining the capacities of local DG units assumes an extraordinary significance, taking the technical, economic and environmental considerations into account. This research tries to study the optimized planning for a grid-connected hybrid microgrid. The case study was conducted in Razi University in Kermanshah, Iran. Due to the stochastic behavior of renewable energies based DG units, the uncertainties about the amount of generated power from these resources are considered using appropriate probability density functions. The problem is a Mixed Integer Non-linear Program (MINLP), to be solved by means of GAMS software. In order to bring about optimized results, microgrid simulation is processed in assorted scenarios, both in probabilistic and deterministic modes. In the end, the results are compared to those resulted from Homer Energy software. 

Description: Maximum Power Point Tracking (MPPT) techniques are most famous application in photovoltaic system to track the maximum power of the PV system. Usually, most of maximum power point tracking algorithms used fixed step and two variables: the photovoltaic (PV) array voltage (V) and current (I). Therefore both PV array current and voltage have to be measured.   The maximum power point trackers that based on single variable (I or V) have a great attention due to their simplicity and ease in implementation, compared to other tracking techniques. With traditional perturb and observe algorithm based on two variable (I and V)  using fixed iteration step-size, it is impossible to satisfy both performance requirements of fast response speed and high accuracy during the steady state at the same time. To overcome these limitations a new algorithm based on single variable method with variable step size has been investigated which has been implemented using fuzzy logic control.  The proposed method has been evaluated by simulation using MATLAB under different atmospheric conditions. The obtained results show the effectiveness of the proposed technique and its ability for practical and efficient tracking of maximum power.

Description: As the penetration level of wind energy in power system increases, stable operation of power system would get impacted by wind turbine's characteristics. The stability issue derived from this fact that the squirrel cage induction generators (SCIG) used in these turbines potentially would cause voltage drop and voltage stability problems in network, regarding to its reactive power absorption tendency. Thus, detection of effective parameters in increment and reduction of unstability occurrence probability could make SCIG based wind farm predictable and eventually cause improvement in voltage stability margin of whole of power system. In this paper, effective factors of wind farm operation connected to the network are assessed and studied in two sections. The first section includes parameters which depend upon substantive and functional characteristics of induction generator and could threat the stability of power system. The second section containing such parameters and characteristics of power system as which are able to affect the stable operation of SCIGs and can be lead to instability in whole of the power system. Eventually reactive power has been identified as more effective option in system designing. The studies are concentrated on voltage stability and small signal stability. In order to make the results more practical, the 660KW inductive generator which is widely used in Iran is studied in this paper.

Description: - A project is undertaken by the College of Engineering Bhubaneswar, Odisha, India to design and develop a biogas production, purification, compression and storage system suitable for the use as a cooking gas in rural households. The biogas is produced in a floating drum type digester by the anaerobic digestion of kitchen wastes. The design is the foot lever compressor which allows the users to stand and compress using foot lever and a valve system, which will allow for variable work input for compression. The final prototype is able to compress the biogas to approximately 4bar in a 0.5m3 tank. In addition to the compressor, there is also a fibre container with steel wool to act as a hydrogen sulfide scrubber in-line with the inlet of the biogas to the compression system. The result showed that the system could compress biogas into a container, 4 bar pressure and operating time of 30 min. 

Description: This study presents techno-economical analysis of grid connected photovoltaic system for powering the Madan Mohan Malaviya University of Technology, Gorakhpur situated at Northern sub-region of India. Load data of university is taken from the Substation and solar data is taken from solar resource setup at the university. The system is optimized for the load and solar data by the HOMER software. Different rating of photovoltaic panel and inverters are studded in the search space. The best feasible system is chosen according to net present cost of the system and carbon dioxide reduction. From the results, it is found that 500kW PV panel and 500kW inverter is the optimal solution for university. This system has 37% renewable fraction and cost of electricity is just about $0.1/kWh. This system will reduce the emission of CO 2 gas about 544 tones in a year.

Description: Among renewable sources, wind source is the more sympathetic and favorable source because it is free from pollution and no carbon die emissions as it appraised in conventional energy sources. Based on existing literature, the development of wind-generator dynamic model is of great interest nowadays. In this paper, a complete dynamic wind-generator mathematically modeling approaches for wind energy system is carried out. Moreover, due to uncertain wind speed circumstances, it is desirable to evaluate the state of the art stability and controller performance analysis for wind-generator unit through feedback control techniques based on field oriented control concept, which plays a significant role in power system stability and control. The proposed dynamic wind-generator system model consists of three phase cage rotor induction machine unit, and it is intended in Matlab software tool for the simulation purpose. The dynamic wind-generator system stability and control design has broadened prospectus for the applications and developments.   Among renewable sources, wind source is the more sympathetic and favorable source because it is free from pollution and no carbon die emissions as it appraised in conventional energy sources. Based on existing literature, the development of wind-generator dynamic model is of great interest nowadays. In this paper, a complete dynamic wind-generator mathematically modeling approaches for wind energy system is carried out. Moreover, due to uncertain wind speed circumstances, it is desirable to evaluate the state of the art stability and controller performance analysis for wind-generator unit through feedback control techniques based on field oriented control concept, which plays a significant role in power system stability and control. The proposed dynamic wind-generator system model consists of three phase cage rotor induction machine unit, and it is intended in Matlab software tool for the simulation purpose. The dynamic wind-generator system stability and control design has broadened prospectus for the applications and developments.

Description: A two-dimensional (2D) numerical model was used to simulate the use of a phase change material and inner fins incorporated to a PV panel, in order to control the temperature rise of the PV cells at various inclination angles from 0 º to 90º  with respect to vertical at increments of 15°. The PCM (RT25) is placed in a cavity directly in contact with the PV panel. This cavity enclosed on both sides by aluminum layers, and contains extended surfaces (fins). This PV-PCM system is studied numerically using finite volume method. The predicted temperatures have been compared with experimental and numerical data of the literature and a good agreement was obtained for both the isothermal contours and time evolution of the temperature. The  bulk  of  the  PCM  melting  within  the  system  is  dominated  by  natural convection for angle inclination lower than 45 º.  In other hand, for the inclinations higher than 45º the heat transfer in conduction mode increases until at 90º, where natural convection disappears completely and the conduction manifests alone. The obtained results reveals that the temperature of the PV panel increases with the increase of the inclination and that small inclinations (lower than 45 º) allow for a better cooling of this panel.

Description: In this study we present the simulation results of a small rooftop PV system with a nominal power of 2KWp under the climate of Oujda city (North East of Morocco) using high quality data measured at ground level for a period of one year. The results show that for an annual global horizontal irradiance of 1891KWh/m², the system is able to provide a yearly electrical production of 3230.1 KWh for a total load of 1538 hours/year and with a mean system efficiency of 8.6%. Generally, the integration of PV systems for small utility scale in Eastern Morocco and especially in the building is very promising, and the results of this study can helpthe local political and economical actors in the field of solar energyto develop strategies and programs to enhance the PV integration on buildings.

Description: Worldwide, power generation from fossil fuels is currently in jeopardy due to carbon dioxide emissions that directly influence the greenhouse effect and thus, climate change. This has led to seek or encourage the use of other sources of power generation, such as hydropower. Small Hydroelectric Plants (SHP) represent a suitable alternative for electric power generation in Colombia due to favorable conditions in its operation and the low environmental impact compared with other available energy sources in the country. SHPs, within the Clean Development Mechanism, are considered a source of clean energy with minimal impacts on the environment. This article presents a review of the existing methodologies for assessing greenhouse gas emissions and the implementation of the ACM0002 methodology in a SHP in Colombia, calculating an updated emission factor in the country.

Description: All the existing energy sources have environmental, social and economic impacts. The greenhouse effect which results global warming, air pollution, and energy security have led to increasing interest and more development in energy conservation. Electrical energy conservation is one of them. In this research, critical electrical energy situation in one of the developing countries in the world-Bangladesh was considered in general. It is possible to serve maximum number of electrical energy consumers by maintaining proper use of the electrical energy. During hot summer the electrical power shortage is about 1000 MW to 1500 MW each year. If energy conservation is achieved through human behavior change, around 390 GWh of electrical energy per month and 4,683 GWh per year can be saved in Bangladesh.  A related case study is conducted for this research. It is possible to save the electrical energy through behavior change from 3% to 20%.

Description: Renewable energy sources are fast growing. Nowadays much effort has been made by inventors to devise new and more efficient configurations of wind turbines. This paper describes mechanical design and resultant-force dynamic simulation of innovative wind turbine structure HASWT. The innovation in wind turbine structure includes flat shape of its blades and their orientation that minimizes the axial component of wind force that generates, in turn, disturbing axial forces on the rotor bearing. Instead, all power of the wind is spent to generate useful rotary or radial force that drives the rotor shaft. This enhances the efficiency of the turbine as compared to complex shape blades in traditional HAWT. The distinctive feature of the system is an oscillating shield that automatically protects the generator shaft at extreme wind speeds from over speeding, and therefore generating power above its capacity or even causing physical damages. The center-point force dynamic load models on the rotor blades have been derived for various wind conditions. The simulation algorithms have been tested in MATLab Simulink environment. The results of simulation show the efficacy of the system and an advantage of using this system with the over speed shield protection

Description: Solar energy is a potential resource among the various renewable energy options which is clean, inexhaustible and eco-friendly. The development of usage and installation of PV system needs a suitable solar policy making plan through proper assessment of solar PV Energy potential in Odisha. This study presents a very simple methodology for estimating the photovoltaic potential of Odisha using the PVGIS online software. The presented method is also useful in determining the PV potential of almost any state, country and region that covers the database of PVGIS. The study divides the total geographic area of Odisha into 1195 square areas with each having its particular coordinate approximately at the midpoint of the location. The PVGIS software is used to evaluate the value of incident solar radiation and generated PV energy at each site. The evaluation of PV Energy Potential includes implementation of four cases that differentiates the PV system according to its technology and structure. The evaluation of energy potential on each four cases estimates two important parameters that are total incident Global radiation for a year and total annual PV Energy production. PV potential of Odisha using the estimated data is presented in the form of rasterized plot.

Description: In this paper, the transesterification of waste animal fat with methanol is studied. The transesterification reaction is affected by parameters like catalyst concentration, reaction time, and reaction temperature and methanol quantity. In this work, optimization techniques such as central composite design and response surface methods have used to find best combination of transesterification parameters to obtain maximum biodiesel yield. The combined effect of catalyst concentration, reaction time and methanol quantity on biodiesel yield were investigated and optimized by using response surface method. XLSTAT software has used to generate a second order model to predict biodiesel yield as a function of catalyst concentration, reaction time and methanol quantity by keeping reaction temperature (55 0 C to 60 0 C) for all experiments. 3D surface plots have been developed to predict maximum biodiesel yield. A statistical model predicted the maximum waste animal fat methyl ester yield of 85.93% volume of oil at optimized parameters of methanol quantity (35% volume of oil), base catalyst concentration (0.46% weight of oil) and reaction time (90 minutes). Experimentally, maximum yield of 91% was obtained at above parameters. A variation of 5.56% was observed between predicted maximum and experimental maximum yield. This is there within the acceptable variation between theoretical and experimental value.

Description: Electricity production by solar energy can reduce greenhouse gas (GHG) emissions which is a big environmental concern around the globe especially in the countries like Bangladesh. Bangladesh is a small country in South Asia with a huge population. The country has many isolated areas that are not connected to the national grid. People living in those off-grid areas mainly use diesel generators that emit GHGs into the atmosphere contributing to global warming. Electricity production using solar energy can be an attractive alternative from economic and environmental perspective. The present study attempts to conduct a techno-economic assessment by developing a bottom-up data-intensive spread-sheet-based model. The model estimates the unit cost of electricity generated by a 3.40 kW p stand-alone solar photovoltaic system (PV) for an isolated locality in Char Godagari, Rajshahi. The island has geographical coordinates of 24°28'6"N and 88°19'25"E and is situated in Rajshahi district. The unit cost of electricity by solar energy was found to be $0.72/kWh or 55.47 Bangladeshi Taka (BDT)/kWh with a net present cost of $12,027.83 or BDT 926,142.55 for the selected location, Char Godagari. The results show that battery is the most expensive component of the solar PV system. A sensitivity analysis was also conducted to see the impact of various input parameters on the unit cost of electricity.

Description: The demand of electricity is increasing day by day throughout the world. Due to limited amount of fossil fuel it is important to design some new non-renewable energy systems that are able to decrease the dependence on conventional energy resources. A hybrid off-grid renewable energy system may be used to decrease dependency on the conventional energy resources. Optimization of hybrid system is a process to select the best combination of component and there cost that are able to provide cheap, reliable and effective alternative energy resource. In this paper photovoltaic system, wind turbine, diesel generator, battery backup and converter have been simulated and optimized for Measurement & Instrument Laboratory in Electrical Engineering Department of Madan Mohan Malaviya University of Technology at Gorakhpur, India. In this system, primary source of power is solar photovoltaic system and wind turbine whereas diesel and batteries are used as backup supply.  HOMER software has been used to simulate off-grid system and it checks the technical and economical criteria of this integrated system. The performance of each component of this system is analyzed and finally sensitive analysis has been performing to optimize the hybrid system at different conditions.  

Description: In addition to the photocurrent, the dark current of solar cell plays a vital role in determining the overall efficiency of a solar cell. In this paper, the injected dark current of a p + n junction solar cell and that of a p + n n + back-surface-field cell have been studied analytically, taking into account the band gap narrowing effect that exists at high doping concentrations. It is observed that there is a significant difference in the magnitude of the injected dark current obtained when the band gap narrowing effect is taken into consideration as compared to the case when it is not considered. Also, it is observed that the magnitude of the injected dark current decreases for smaller values of back surface recombination velocity, which corresponds to BSF structure. This is one of the reasons why the p + n n + BSF solar cell has better output than the conventional p + n cell. The results obtained here are similar to the case of an n + p p + solar cell reported earlier by researchers.

Description: The present study deals with the performance of a 1.6kWp grid connected PV system installed at Batna University, in Algeria. The average solar energy received was 5.21 kWh/m².d, the grid connected PV system seems to be a good candidate for generating electricity in this region. The system was monitored during one year of continuous operation and data analysis to evaluate the performance of the grid connected PV system. The performance ratio of the system ranged between 51 and 61%. Furthermore, the total produced energy by the PV array was 1931.7kWh and the supplied energy to the grid was 1705kWh. The annual final yield was 1065.6kWh/kWp. Moreover, an analysis of the energy losses in the system was performed, this makes it possible to determine the effect of the capture and system losses on the total energy balance of the system. All the electricity generated by the system was fed into the internal electrical grid of the university.

Description: The objective of the present study is to evaluate the thermal performance of the photovoltaic thermal solar air collector. In fact, theoretical and numerical studies of PV-T air collector operating in dynamic mode have been performed. Based on the resolution of thermal balance equations using finite element method, a thermal model has been developed. The temperature profiles of glazing, solar cells and outlet air have been determined. The influence of some parameters such as air mass flow rate, ambient temperature, solar radiation, the length of the collector and air velocity has also been studied.

Description: The continuous power supply for rural areas can be possible by using renewable hybrid power generation system and also reduction of the energy storage devices for the system. The impact of the shortage of power supply probability, excess power generation, ratio of the energy supply to load demand, renewable fraction  of different types of  energy sources (solar and wind) and the combined system components and their performances are analyzed. The techno-economic feasibility of solar – wind hybrid system with battery backup is fully discussed. The off-grid PV system, PV-wind hybrid system is modeled and simulated using HOMER software. The comparative analysis of different possible configurations is analyzed in detail. It is found from the simulation results that the PV-wind hybrid system has the lowest unit cost of energy as compared to stand-alone solar PV or wind system. So, the PV-wind hybrid system is most suitable for proposed project.

Description: Static Economic Dispatch (SED)  with combined Solar Thermal generation systems incorporating spinning reserve cost is presented in this paper. Particle Swarm Optimization (PSO) algorithm is used as the optimization tool here. Spinning reserve is an  essential requirement in power system network to handle the situations arising during generation or transmission outages. Therefore, incorporation of spinning reserve cost and capacity can provide more realistic dispatch. B-coefficients method is used to determine the losses from the generators for solving the SED. Based on historical data, the output of solar farm is forecasted in this case. Beta distribution function which is the best suited probability density function for irradiance modeling is used to model the output of the solar farm. The uncertainty in solar energy with various seasonal effect is also discussed. Comparative analysis without and with the incorporation of solar farm is carried out. The proposed methodology is tested and validated in IEEE 30 bus test system and South Indian Utility 89 bus test system.

Description: This paper deals with the control of a three-phase voltage source inverter (VSI) for a grid-connected photovoltaic (PV) system. The direct power control (DPC) is combined with a predictive approach for selecting the optimal inverter switching states. This optimal selection is carried out by minimizing a suitable cost function. Moreover, in order to extract the maximum available power from the PV generator, a fuzzy logic maximum power point tracking (MPPT) controller is applied to a DC-DC quadratic boost converter acting as an interface between the PV generator and the inverter. Modeling and simulation of the system were performed by using Matlab/Simulink software

Description: For the past few decades, research has scaled up in the development of environmental friendly alternative fuels such as biofuels that can replace the use of conventional fuel resources. The present work investigates the usage of Pongamia and Orange oil blended with diesel to run a compression ignition engine. Several experiments were conducted with blends of diesel, Pongamia and Orange oil in different proportions to evaluate engine performance and emission characteristics of full throttle position. The results indicate that the values of Brake Specific Fuel Consumption, Brake thermal efficiency and mechanical efficiency obtained with the use of bio-diesel blends are very close, and emissions are less when compared to diesel.

Description: Stability of power converters has become more and more important in the hybrid green energy system because of its difficulties to maintain a stable dc-bus. This paper presents dynamic characteristics of a digital integral gain changeable control dc-dc converter to realize the high stability with suppression of the output capacitance. The integral gain changeable control method uses a variable integral gain, which is changed by the value of load current. The stability analysis is conducted by Bode diagrams. It is shown that the transient response and stability of the integral gain changeable method are better than the conventional fixed integral gain control method even if the output capacitance is smaller than the conventional method. Simulation and experimental results show the effectiveness of our concept presented.

Description: This paper discusses the exergy and energy analysis of torrefaction process for four different residual biomass (wet leaf, rice husk, coconut shell and tree bark). Torrefaction is a thermo-chemical conversion process carried out in an inert atmosphere. The biomass samples are torrified using waste heat from a diesel engine at a temperature of 240˚C for a duration of an hour. Exergy and Energy efficiencies, and exergy and energy saved are assessed with the help of the actual system data. The exergy saved in the overall system is found to be 0.258 kW, 0.702 kW, 1.812 kW, 2.486 kW for wet leaf, rice husk, coconut shell and tree bark respectively. The most efficient biomass in the torrefaction process is tree bark, yielding an energy efficiency of 58.76% whereas wet leaf is the least efficient biomass. It is found that maximum exergy efficiency is obtained from the reactor if the exhaust from the source is in the range 430-470˚C.

Description: The use of biogas as a means of satisfying energy demands is a viable alternative to fuel wood which results in the indiscriminate felling of tress. Animal wastes as organic substrates in the production of biogas provide a cheap and eco-friendly method of managing wastes. In this study, three different animal wastes (Cow dung: pH 1 =7.08, pH 2 = 7.32; Goats’ droppings: pH 1 =5.49, pH 2 =5.26; and Chicken droppings: pH 1 = 5.49, pH 2 = 5.75) were used as substrates in the production of biogas, and the experiment was carried out at ambient temperature for a hydraulic retention time of three weeks. A set of three laboratory digesters was used in the experimental set up, and the performance of the animal wastes was assessed based on the volume and quality of the biogas produced. The amount of biogas produced by the animal wastes in decreasing order is as follows; chicken droppings (18.27 Litres), cow dung (12.55 Litres) and goats’ droppings (5.11 Litres). The order of flammability of the biogas produced is as follows: cow dung 〉 goats’ droppings 〉 chicken droppings.  The following methanogens were isolated; Methanobacterium sp., Methanococcus sp., Methanospirillum sp. and Methanosarcina sp. in the course of the experiment. In this study, cow dung produced the biogas of the highest quality and conclusively can be chosen as the best substrate for biogas production.

Description: The amount of suspended sediment discharge is often required in hydraulic structures design, such as reservoirs design, irrigation-canals design, etc.; but this data is often unavailable or the availability of such data is very limited. The most appropriate and precise method for determining of suspended sediment discharge in channels (or in rivers) is by sampling of suspended sediment as well as the velocity data directly from the channels. Due to many constraints of the field measurements and of the expensive cost to get the suspended sediment discharge data, measurements of suspended sediment, and of velocity are often taken only at certain positions, which are often not in accordance with the standard sampling methods.  These conditions resulted in inaccuracies in predicting suspended sediment discharge; thus, it is necessary to find a simple and an accurate method for determining suspended sediment discharge. The purpose of this study is to find how the suspended sediment concentration and how the velocity taken at certain positions in trapezoidal channels correlate with the suspended sediment discharge. The study also aimed to determine the possibility of errors, including finding correction factors to the improper suspended sediment sampling methods, that are still often carried out in the field. Location studies are focused on nine (9) segments of trapezoidal channel in Mataram Irrigation Channel, in Yogyakarta, Indonesia. The velocity and suspended sediment concentration profiles were measured by using Propeller Current meter and Opcon probes, respectively. The results of the study show that the suspended sediment discharge of trapezoidal channel can be obtained from the measurement of velocity and suspended sediment concentration profiles at z / B = 0.25, measured from the channel side, z , with B is the channel width. Keywords velocity, suspended-sediment concentration, trapezoid channel, suspended-sediment discharge.

Description: This paper deals with the cost optimization of a hybrid solar, wind and hydropower plant using a Particle Swarm Optimization (PSO) approach. PSO is a technique that belongs to Swarm intelligence, an artificial intelligence (AI) technique, known as a Meta-heuristic optimization solver, mostly used in Biology. With the consideration of solar, wind and hydro hybrid system which has become extremely relevant for developing countries, and also the existence of a wide list of constraints, the adoption of PSO technique cannot be avoided. On the other hand, a linear optimization approach was used with Matlab software to solve the same problem. Both techniques were applied to secondary data collected from RetScreen Plus software for the location Accra and results were extracted in terms of distribution of supply by individual sources and cost of hybrid system electricity. Results show in general, an improvement of hybrid system cost of electricity. A histogram was used to show the distribution of supply for the particular load and the equivalent cost of hybrid system that corresponds to it. A khi-sqaure test ws run to compare the two series of data obtained from the two approaches adopted. The Khi-square test show high similarity confirming the reliability of the PSO approach which on the other hand presents the advantage of scalability over a wider range of sources with multiple constraints.

Description: The irregularity of the generated power from wind turbines is caused by the stochastic nature of the wind. It can affect the quality of power and plan of the power supply system. The purpose of control is to adjust the inverter voltage's amplitude and frequency at a variable speed of the wind. This article presents a Generalized Predictive Control application to a wind power converting system with emphasis on the Maximum Power Point Tracking (MPPT). The controller developed consists RST regulator obtained GPC. This equivalent polynomial structure is needed to convert the GPC parameters to be monitored to its RST equivalent parameters. The obtained results have shown that the Generalized Predictive Controller performances were largely better than the PI ones.

Description: In electric power market, electric power must be offered to the customer with high quality and least cost. In a deregulated power system, this is a difficult task because of several complicated problems. With increase in electricity cost of raw materials and its growing demand, an optimal solution is required for operation and design of an efficient power system. Conventional energy resource like solar system can be opted for generating electric energy using Photovoltaic (PV) cells. To address the power flow problems using PV cells, Optimal Line Flow (OLF) solution is used for solving and obtaining an optimal operating result for all the generators in distributed power systems. We proposed an Euclidean affine flower pollination algorithm (eFPA) to addresses the line flow OLF constraint for minimizing the fuel cost, loss, emission and voltage stability index. A multi-objective function for all the above constraints is used in eFPA to solve the OLF constraint. Results proved that the eFPA optimization for OLF constraint proved to be efficient because of its minimization of cost, loss, emission and voltage stability index. The  analysis is performed on IEEE 30 bus system and IEEE 57 bus system.

Description: Wind energy is characterized by fluctuation because of a main intermittent source, which can damage the stability of the electrical network which leads to an imbalance between production and consumption. To resolve this difficulty, an integration of a micro-grid based on a wind farm interconnected to the electricity grid is proposed which presents the first objective of this paper. The two-level inverter is so much used in this domain, but the main limitations of this solutions are the fact that the voltage output presents high ripples and that this inverter is not a practical solution for applications with high power. Thus, the second aim of this paper consists in using a multicellular inverter. The main unit of this farm is based on a three permanent magnet synchronous generators which are entrained by three aero-generators. This unity is connected to a DC bus through three controlled rectifiers. The obtained power is injected to the electricity grid using a multicellular inverter as well as an inductor and resistor filter. The three generators and the proposed inverter are controlled through a vector control. A theoretical study of the suggested farm is parented and simulated using a Matlab/Simulink environment. The obtained simulation results confirm the approach robustness.

Description: Nowadays the distributed generation is being vastly implemented due to its various advantages. Generally a non renewable source is connected in parallel to a renewable source. Normally Photo Voltaic (PV) gives the power necessary by the load. The output of the PV is varying due to various reasons like temperature, irradiation, etc. Distributed generation using micro turbine is a realistic solution because of its friendliness with environment, small in size and high efficiency of energy. If the load is more than PV power capability, micro turbine supplies the remaining power. Due to the varying load conditions, the micro turbine practically compensates all the PV fluctuations of power. Even so, to reduce the fast fluctuations of power, one need to use an energy storage system like battery, ultra capacitor and flywheel etc. Ultra capacitor has been chosen, because of the its high power density and very fast energy storing capability. This paper documents the simulation and analysis of a standalone Photovoltaic / Micro turbine hybrid system and Photovoltaic / Micro turbine / Ultra capacitor hybrid system using MATLAB/SIMULINK as its simulation software. The system is implemented based on the concept of a parallel hybrid configuration.

Description: The use of renewable energy is experiencing a significant growth in the world. With the increasing demand for electric power mainly for the needs of remote and deserted and mountainous regions; the photovoltaic systems, particularly telecommunications and water pumping systems, begin founding great applications. In this topic, the proposed study involves a comparison between the delivered power optimization techniques. Among these techniques there is the technique of truly maximum power point tracking called Perturbation and Observation P&O method, and the optimization techniques with and without sunlight compensation. The last two techniques are less efficient than the first one, but easier in their implementation. In order to increase their performance, an improvement has been proposed. The obtained results were promising.

Description: This paper presents a preliminary techno-economic assessment of isolated mini off-grid power generation which involve locally available renewable energy resources in Ngadu Ngala sub-district, East Sumba, Indonesia. Currently, only 6 hours of supply available from diesel generator is available for the area, started from 6 PM until 12 PM. In this study, 10 years projection on domestic load demand is provided as the demand. The study is performed to prolong the supply duration from 6 hours to 24 hours daily. The analysis is mainly intended to find long-term optimum sizing of power generation system, which involve significant renewable energy penetration, with the least cost of energy. Based on the simulation performed by HOMER software for 24 hours supply, the most optimum sizing is a hybrid system which consists of 200 kWp Photovoltaic (PV) and 72 kW diesel generator, with energy cost of only US$ 0.281/kWh, which is quite cheap. Moreover, the penetration rate of PV is reached 51%.

Description: A nonlinear backstepping flux observer (BFO) for two control strategies applied to directly driven wind synchronous generator is proposed. A backstepping control (BC) and a sliding mode control (SMC) strategies are developed for both converters: the stator side converter (SSC) and the grid side converter (GSC). Using Lyapunov stability technique, one may guarantee the global stability of the wind energy conversion. The efficiency of the two non linear control strategies has been proved in terms of tracking and precision. Then, a comparative study between four possible combinations of control is illustrated and simulation results have shown high performances of the wind system controlled by BC strategy. Finally, stator resistance variation is introduced and it proves the robustness of the BC strategy applied to both converters with the BFO.

Description: The XXI century came with a lot of technological advances, being most of them productive and helpful in the human life, looking for deeply there is a huge problem that the population and the planet inherited from XIX and XX centuries and is called global warming, now in this century that issue is affecting the whole planet in many different ways. One of the solutions to this problem is to eliminate our fossil fuel dependency changing it for a sustainable and clean way as are the renewable energies, and most of it the solar one, considered as the greatest one. Which through Solar cells, it is possible to capture and converting it into electricity, but nowadays the conversion efficiency is around 15%, lowering its attractiveness and its options as a way to replace the actual energy sources like fossil fuels, that is why different studies have been performed in order to increase this efficiency by modifying the physicochemical structure of the semiconductors used in a Solar cell among other techniques that in general the main purpose is to capture and convert more solar energy and decrease the different losses in the conversion process inside the cell. In this paper a deep study it is performed of the Gallium nitride (GaN) layer Effect in a Two Layers Solar Cell based on Aluminium gallium arsenide (AlGaAs), Silicon (Si) and Indium phosphide (Inp) semiconductors, with the aim of replacing the diffusion doping process with the proposed scheme of solar cell, which presents different advantages as is going to be observed along this study.

Description: In this paper an approach to model different types of PV modules using single diode model is presented. The proposed method utilizes the characteristics of diode ideality factor, shunt resistance and series resistance independently for developing accurate solar PV model. Apart from this, the proposed model utilizes experimental values obtained from the solar array simulator for validating the proposed approach. The procedure mainly focuses on developing an accurate method for thin film solar modules using a simplified approach. The proposed model is implemented in MATLAB and is verified with existing model.  The experimental results are obtained from a 2 Kw CHROMA solar array simulator.

Description: In this paper, a modified frequency impedance scanning tool is developed to scan wind turbine side impedance at various frequencies.  Voltage harmonic injection technique by retaining the fundamental frequency is used to determine the impedances at any given subsynchronous frequencies.  Additionally, the tool is designed to incorporate the entire frequency range of interest in a single simulation rather than the traditional multi-run or looped frequency scanning techniques.  The principle of frequency scanning analysis is used to determine the risk of sub-synchronous control interaction (SSCI) before an interconnection of wind farm. The tool measures the impedance of non-linear models containing power electronic devices (such as wind turbines) at sub-synchronous frequencies (SSF).  The tool is validated with a passive RLC circuit at a known resonance frequency in PSCAD and also for non-linear systems consisting of representative Doubly Fed Induction Generator (DFIG) wind turbine model and a designed SSCI test grid.   The tool developed is used to determine the behavior of a representative DFIG wind turbine at sub-synchronous frequencies and its susceptibility to SSCI events under various operating conditions.  Sensitivity of various wind parameters at wind farm level on the impedance exhibited by the wind generation plant is studied.

Description: Hydrogen storage as a part of hydrogen energy system is needed to be investigated deeply for common usage of the system. Many alternative hydrogen storage media have been investigated in last decade to solve efficient hydrogen storage problem. Storing hydrogen in adsorbents physically is a significant solution. Carbon based materials and framework structured metal-organic compounds also have intense attention for hydrogen storage by physical adsorption. In this work, the effect of surface area and dopant percentage on the hydrogen storage have been emphasized. Different amount of platinum loaded activated carbon as dopant milled with the activated carbon and Cu-BTC as matrix materials. It is found that the increased amount of dopant cause more adsorption on the adsorbent surfaces. Thus, the hydrogen storage properties increases. But, the excess amount of additive decreases the micro-porosity by the way hydrogen storage.  4 wt. % of additive, platinum loaded activated carbon, increases the hydrogen uptake approx. 10 and 15 % in activated carbon and Cu-BTC respectively. In the contrary, 10 wt. % additive decreases hydrogen uptake approx. 2 and 25 % of adsorbents in the same order.

Description: In recent years, grid connected photovoltaic system has emerged with its simplicity, reliability and endurability. The ranges of grid tie inverters (GTI) are classified as small scale as several tens of kilowatts and large scale as hundreds of megawatts. Accordingly, the standard of interconnecting to the grid is made higher extent in improving its power system reliability, efficiency and cost. Moreover, the working of grid connected inverter primarily depends on robustness in control strategy, even working in abnormal grid conditions such as deviation of voltage and frequency. This review focuses on updating grid standard codes and regulations, in addition overview of recent control strategies and direct power control. The structure of the phase locked loop (PLL) with grid synchronization techniques for single phase and three phase is discussed in brief. Investigations are performed for a fault ride through capabilities with detailed analysis of islanding detection methods with its types. The PV- STATCOM control functionality for the enhancement is discussed in detail.

Description: This paper aims to propose and develop a research platform which can be utilized for rapid prototyping of control algorithms of power converters used in the field of renewable energy, such as the photovoltaic systems. This study investigates the use of the Field-Programmable Gate Array (FPGA) to control the DC/DC power converter and the voltage inverters used in solar photovoltaic pumping systems. The power circuit of the pumping system consists of a PV system, a DC/DC converter, a two-level voltage inverter and an induction motor. The control system is based on an MPPT control algorithm and a Direct Torque Control with a Space Vector Modulation (DTC-SVM) based on proportional-integral controllers. In order to perform the hardware in the loop, the power circuit is realized using the Simulink blocks and the control system is designed using the Xilinx System Generator (XSG) tool. The VHDL code and the bit stream file of the suggested control algorithms have been automatically generated using the XSG tool. The hardware co-simulation step is carried out in the laboratory utilizing an FPGA Virtex 5 ML 507 and the Matlab/Simulink environment. A comparative study between the classical DTC and the DTC-SVM is presented. The FPGA-performance in terms of computation power is demonstrated.

Description: Micro-grids are consisted of some interconnected networks such as distributed energy systems (resources and Loads) which are able to operate in gird connected and islanding modes. According to different loads in terms of feeding priority, consumers can help Micro-grid control center (MGCC) to do their best optimized scheduled operations. Then it could provide power for critical loads by controlling interruptible loads or displacement of load at different prices . Demand response (DR) plays an important role at electricity market in order to balance power generation and demand level required. Overall consumer pricing can be very useful in reduction of the operating costs, especially when market prices are high. In addition, by using this method, consumers can reduce their payment for less important loads. In this paper, the optimal operation of micro-grid in presence of demand response will be investigated in order to increase social welfare and flattening the load curve at an acceptable level. Multi-objective optimization problem will be solved by Epsilon limitation method with nonlinear programming (NLP) using  General Algebraic Model System (GAMS) software package. The proposed algorithm will be implemented on a 17 bus micro-grid. The results indicate that proposed algorithm has ability to improve of micro-grid performance in scheduled operations.

Description: System stability is one of the most imperative requirements in a Microgrid designing to have an efficient, secure, and sustainable performance using renewable energy sources. In this paper, as a cardinal objective, the voltage and frequency stability is achieved by power balancing technique using load shaving and load shifting method. In particular on this occasion, controllable load is the only manageable load by which we can optimize cost using those two techniques and therefore the cost can be greatly reduced; thus saving substantial amounts of money to reduce electrical power consumption during peak/mid-peak hours. Moreover, the capacity of designed power system can be optimized by the same token. This letter proposes a controller to handle the frequency and voltage stability based on the generation and load; it can also track down the optimal cost line to facilitate the entire distribution policy. An energy storage system has also been proposed to manage those peak hours/loads in case of insufficient/surplus of the net generation and sub-sequential cost analysis has been presented as well. The feasibility of this method has been authenticated very meticulously by Matlab/Simulink verification

Description: In this paper, a real case study about energy efficiency improvement of the building of the Software and Services Development Companies' Space at the Technological Center of 'EL GHAZALA' is presented. On the one hand, this study aims to highlight the importance of the energetic and financial gains realized upon the respect of some bioclimatic design rules and solar water preheating system integration. It also aims to present the Tunisian thermal regulation limits. On the other hand, it provides a method for the design of glazed surfaces and overhangs or fins while introducing the way to use the SOLO and CLIP software for the energetic and financial gains calculation. In a first step, building thermal needs were studied, using the CLIP software, for two specific cases: a first case where the building is under the most common standard conditions in Tunisia and where only glazed surfaces dimensions and orientations are optimized; and a second case where higher performance materials and overhangs and fins are used. It came out that half of the thermal energy needs could be saved and low investment payback of about nine years could be reached. Another outcome is that Tunisian thermal regulation should be updated in order to further promote the use of more efficient building materials. Then, in a second step, the effect of solar water preheating system integration was studied using the SOLO software. It turned out that its integration could cover about 64% of the building's heating needs.

Description: MMC converters are an interesting solution for HVDC applications and renewable energy transport . This paper presents a mathematical analysis of the impact of various Phase Disposition PWM strategies on the circulating current which is one of the important MMC converter issues. The considered strategies are: Phase Disposition PWM (PDPWM), Phase Opposition Disposition PWM (PODPWM) and Alternative Phase Opposition Disposition PWM (APODPWM). Depending on the adapted modulation strategy, the proposed analysis proves that the circulating current varies from a DC component to a high current with high frequency components and a dominance of the second order harmonics. It is also demonstrated that PODPWM and APODPWM modulation strategies satisfy the balanced operation condition where only N sub-modules among the 2N available sub-modules are inserted into the phase leg and consequently ensure (N+1) voltage levels in the output voltage. Simulation results of a 2.7 MVA MMC converter are presented to verify the validity of the proposed methodology and analysis.

Description: Nowadays, distributed generation (DG) is a new option in the power systems to meet the electrical demand growth as well as conventional methods such as substation reinforcement and feeder replacement. This paper presents a new approach to solve single and multi-objective distribution system expansion planning problem including DG and conventional method simultaneously. Since this optimization problem has a nonlinear complex nature, classical mathematical method cannot guarantee to achieve the global optimum solution. So, to overcome this encumbrance, a heuristic evolutionary algorithm based on binary particle swarm optimization (PSO) is proposed. The objective functions of this optimization problem are total expansion cost, voltage deviation, and system losses. The model resolves decision variables as follows: location and size of the DG units, new transformers, and upgraded feeders. This paper proposes several non-dominated solutions, so the decision maker can choose the optimal solution based on the importance of the different objectives. The 9-bus and 30-bus distribution test systems are utilized to show the effectiveness of the proposed method.

Description: The production of wind generation has expanded considerably today. The main problem with wind generation system is to regulate the voltage at wind turbine terminals even under abnormal grid conditions.This is mainly as a result of consumption of non active power from the grid during grid disturbances. This paper investigates an improved Synchronous Reference Frame control; Dual Decouple Synchronous Reference Frame (DDSRF) based control for Dynamic Voltage Restorer (DVR) to upgrade the dynamic response of wind energy system. The proposed method uses  DDSRF PLL for extracting clean grid voltage and  phase angle even under adverse grid conditions. The proposed control scheme provides the ability for fixed speed wind generator to ride through under voltage interruptions in the grid to meet the latest grid codes. The proposed control is competent of stabilising  the voltage at the wind turbine terminals under symmetrical sag/swell and asymmetrical fault conditions. simulation studies have been peformed in MATLAB/SIMULINK to manifest the effectiveness of proposed control strategy

Description: Renewable energy in The Bahamas holds promise as an alternative for electricity production, however, the country is heavily reliant on fossil fuels for electricity. This study examines the benefits of solar and wind energy on a community scale on the island of New Providence in The Bahamas. The electricity usage of 500 homes (a mix of luxury and normal) is produced by a combined power generation system that includes rooftop PV and a wind turbine. The system is grid connected and assumes a net billing policy because of the lack of a net metering policy and incentives in The Bahamas. An economic analysis along with sensitivity and risk analyses are performed to determine the system’s feasibility and how uncertainty in parameters affects its viability. To perform the analysis, the RETScreen software suite is used. It is found that a combination of solar and wind for electricity generation is economically feasible in The Bahamas even with the lack of incentives. The system produces a surplus of electrical energy on an annual basis with a greenhouse gas reduction of 2,026 tons of CO 2 per annum. The sensitivity and risk analyses indicate that the electricity rates (electricity bought from the grid) and the electricity export rates (electricity sold to the grid) significantly influence the NPV and payback period of the system. The results also show, with 95% confidence, the NPV is within the range US$14.0 million and US$25.1 million.

Description: This paper presents controller scheme to maximize the turbine output power and thereby improve the efficiency in oscillating water column (OWC) wave power plant equipped with Wells turbine and doubly fed induction generator (DFIG). The scheme is based on flow coefficient estimation and controller design for tracking of rotational speed. Initially, a linear reference tracking (LRT) approach is applied to achieve the maximized output power by establishing a linear relationship between reference rotational speed and input pressure drop. This follows implementation of fuzzy theory based maximum power point tracking (FMPPT) approach to provide the optimal speed reference. Then, a backstepping (BS) controller is designed to track reference rotational speed of DFIG so as to improve the output power. The BS controller is derived using Lyapunov stability theorem which ensures the stability of the overall closed loop system. The advantages of the proposed control scheme over conventional PI control and the uncontrolled system is demonstrated for regular waves and irregular waves. Finally, the FMPPT-BS control approach has been validated with JONSWAP irregular wave model.

Description: The primary objective of this study was to investigate that either Pakistan needs or not a single regulatory authority for its energy sector by means of integrating Oil & Gas Regulatory Authority (OGRA), National Electric Power Regulatory Authority (NEPRA) and the regulatory part of Directorate General of Petroleum Concessions (DGPC) in to a single entity “National Energy Market Regulatory Authority” (NEMRA) . To achieve this objective of research, descriptive analysis along with binary logistic regression technique were used. The results showed that due to the current performance of existing energy regulatory framework it is necessary to establish a single autonomous energy regulatory authority (NEMRA) for the energy sector of Pakistan in order to put it out of crises towards grooming and prosperity.

Description:   The paper describes the procedure for parameter tuning of the power system stabilizer, as part of the structure of the automatic voltage regulator of synchronous generator AVR. Parameter tuning is based on a method that uses a mathematical model of synchronous generator on the power system. The parameters of the mathematical model of synchronous generator are determined by identification. Application of the identified mathematical model defines the function of dependence of the characteristics of the voltage regulator of the synchronous generator to the parameters of the controller. Developed method for parameter tuning is tested on the real laboratory system.

Description: The Microgrid is a power system network which assumes a cluster of loads and microsources operating as a single controllable system providing both power and heat to its local area. This paper presents a Proportional Resonant (PR) controller design in discrete domain for regulating the active and reactive power output for a three-phase AC Micro-Grid system. The PR controller reduces the steady state error and help in synchronous d-q transformation in three phase system. It employs a Voltage Sourced Converter (VSC) which is configured to operate as a current source through an interface L-filter. The power is controlled indirectly by controlling the inverter’s output current. This paper also presents a comparison of THD between Proportional Integral (PI) and Proportional Resonant (PR) controllers and indicates that the THD using Proportional Resonant (PR) controller is less than the Proportional Integral (PI) controller by more than 2%. The complete work is designed and implemented in MATLAB/SIMULINK.

Description: In 2013 the Grozny State Oil Institute within the consortium ‘Geothermal resources’ started a pilot project to build a geothermal plant on the basis of the most promising XIII layer of the Khankala thermal waters deposit of Russia. Planned capacity of the projected facility is 5.45 Gcal/hour, which will heat a greenhouse complex. A “doublet” system is going to be applied which is represented by a closed loop of one production and one injection well with reinjection of all used water back into the layer. This technique allows maintaining the reservoir pressure and thus productive rates, and reducing the ecological effects of geothermal development to minimum. In order to predict the changes in the temperature of the resource (it goes down as a result of the injection of cold water) it is necessary to conduct a numerical simulation. Modelling permits to have general ideas on «doublet» system functioning in its hydrogeological environment, allows choosing best exploitation parameters and distance between production and injection wells bottoms in order to achieve sustainable use of the resource.

Description: Melastoma malabathricum L. dye was investigated as a sensitizer in DSSC after treatment with five different organic acids: citric, deoxycholic, lactic, ascorbic and acetic acids. These treated dyes were evaluated as sensitizers of dye sensitized solar cell and the performances were investigated. The treated dyes were shown to enhance the short circuit photocurrent density ( J sc ) and hence contributing to the increase in power conversion efficiency. The overall efficiency enhancement of the acidified treated dyes were due to the combined effect of increased light absorption at visible range, efficient adsorption of dye molecules onto TiO 2 film and low electron transport resistance for efficient electron diffusion at TiO 2 /dye/electrolyte interface. Dye treated with 1000 mM citric acid showed the best performance with overall conversion efficiency of 0.79±0.01%, which is an increment of 41% of the overall cell performance efficiency from the original, untreated dye (η = 0.56±0.01%).

Description: In this paper we present the interests of the hardware implementation of control algorithms for wind emulator based on DC-Machine. This work focus on modeling a horizontal axis wind turbine, a DC-Machine with independent excitation and its control via PI controllers and a fourth quadrant chopper by exploiting mathematical equations. Moreover, simulation results are analyzed and discussed using Simulink and XSG (Xilinx System Generator) showing the performance of our application. Through the tool XSG, algorithms are implemented on FPGA (Virtex-5 LX50T).

Description: This work aims to present a comparative study of four controllers for Double Fed Induction Generator (DFIG) based Wind Energy Conversion System (WECS). The DFIG is directly connected to the grid and driven by the rotor through an AC/DC/AC converter. A model was developed for each component (Turbine, DFIG and Rectifier-Filter-Inverter) of the wind system. The PWM control method is applied to the inverter to drive the DFIG from the rotor circuit. To ensure high performance and better enforcement of DFIG, a direct vector control strategy of active and reactive power of the stator has been developed. The synthesis of conventional PI controller and advanced RST, Sliding Mode (SM) and Fuzzy Supervisory (FS) controllers is performed. The system’s performance has been tested and compared according to reference tracking, robustness, and disturbance rejection. A set of simulation studies are carried-out on a WECS model to prove the effectiveness of the proposed controllers design.

Description:      This article deals about reduction of power drawn from the supply system in smart environment during un-certainties in the power generation. Supply system in this work is the system which consists of an intermittent power source and a storage system to support whenever there is deficit in power generation. A small micro grid system is considered for this study which has critical and non-critical load present in it along with storage system and Electric spring. An attempt is made to study the performance of Electric spring in reducing the power drawn from the supply system under different non-critical loads during un-certainties or power deficit conditions of the source. The effect of reactive component in the non-critical load is examined separately for the considered battery storage system. All the simulation models have been developed in MATLAB.         

Description: The wind and solar energies are the most available among other renewable energy sources in all over the world. In present years, because of the rapid advances of power electronic systems the production of electricity from wind and photovoltaic energy sources have increased significantly. In this paper, the performance of the wind/PV hybrid system is studied under different grid perturbation conditions. The wind/PV hybrid system model has been implemented in Matlab/Simulink environment. The wind power system and PV arrays are controlled to attain maximum power output from them. The controller used for inverter maintains constant DC voltage at DC bus while injecting only active power to the grid. The common grid perturbations considered in this study are balanced voltage dip, voltage unbalance and harmonic distortions. The simulation result reported in this work also shows that, the performance of the presented hybrid system model is not affected by the grid disturbances considered.

Description: The objective of this paper is to harvest maximum power from the solar panel using voltage based MPPT circuit for low power application under varying atmospheric conditions.  A voltage based tracking system consisting of a voltage sensor, DC-DC boost converter, maximum power point tracker and a LED lighting load is designed and developed. The analog MPPT controller using direct feed forward PWM control signal for DC-DC converter operated in the continuous conduction mode is the principle block performing the tracking operation. Since the output of solar panel is nonlinear, the optimal power point will vary due to change in irradiance and temperature. Irrespective of the change in atmospheric conditions, the voltage sensor developed here has the ability to generate accurate reference voltage in accordance with the panel output and thereby maintains maximum power at the load. The experimental results have proved a power conversion efficiency of 95.46 % in clear sky condition, and (90.49 to 93.78) % in partial shading conditions resulting from the feed forward control technique employed in the MPPT circuit. The proposed tracking system is less complex and low cost one that has high tracking efficiency with less fluctuation in real time dynamic conditions. 

Description: Food waste and other biodegradable matter in the municipal solid waste stream are a source of environmental and public health concern in cities of developing countries. Anaerobic digestion applied to urban solid organic waste treatment is an option to address those issues and to produce biogas, a renewable energy source. This paper presents the design and economic evaluation of a prototype biogas plant fed by food waste from a restaurant in Mexico City. On average, the restaurant produces 40.5 kg/day of food waste with 23.0% total solids (TS) and 94.2% total volatile solids (TVS). With this amount of food waste, around 69.2 L/day of feeding substrate with 12.7% TVS are produced. Considering an operating temperature of 20°C, total anaerobic digester volume required was calculated at 6.0 m 3 . Plant design comprises a continuous stirred tank reactor (1 m 3 ) coupled with a conventional digester (5 m 3 ). Organic loading rate and hydraulic retention time were 1.9 kg-TVS/(m 3 ∙day) and 86 days, respectively. The plant is expected to produce 6.1 m 3 /day of biogas for use as a cooking fuel at the same restaurant, leading to LP gas savings of 692 kg/year. Plant investment cost was estimated at MXN 129,000 (~9,550 USD). Economic evaluation showed that the biogas plant profitability is highly dependent on LP gas price and its annual growth rate. The prototype biogas plant described here is a step forward in the conception of a biogas facility suitable for cities in developing countries to collaborate in solving their environmental, public health, and energy concerns.

Description: Renewable energy offers convenient energy solution to the population live in isolated areas. The residents can utilize the locally available energy resources for fulfilling their need for electricity. The availability of electricity in the darkness of night facilitates higher productivity irrespective of gender. In this paper, design of a solar PV-diesel mini-grid system has been presented for a locality in Char Parbotipur (25.75°N 89.66°E). This island is situated 20 km north-east from Kurigram district, Bangladesh and surrounded by Brahmaputra river and Dudhkumar river, far from the national grid. Very few residents use stand-alone Solar Home Systems (SHS) and diesel generators. Diesel generators have environmental concern which can be minimized by using hybrid renewable energy systems. This paper aims at designing an optimal energy system consisting solar PV having diesel generator for fulfilling the load demand. The proposed energy system can generate electricity at a cost of $0.461/kWh for a load of 115 kWh/day. Sensitivity analysis is presented to understand the effect of diesel price and solar irradiation on the cost of electricity and net present cost of the system. Comparison between the proposed hybrid renewable energy system and an energy system comprising diesel generator only are also presented to understand the effect of solar PV integration with diesel generators for environmental benefits.

Description: This paper presents a new synchronous rectification (SR) for phase shift modulation (PSM) LLC resonant converters. The SR for PSM LLC resonant converter has difficulty because the secondary current is not in phase with both primary current and the voltage across the transformer. Furthermore, the open-loop SR for phase shift modulation does not perform well because the optimum pulse width is highly dependent on operating conditions such as the duty ratio of primary switches and the load current condition. The proposed SR utilizes the average load current to predict the optimum pulse width of SR so that the detection circuit for SR is not required. Effectiveness of the proposed SR is simulated and experimentally verified.