ALBERT

Description: The magnetic levitation force exerted on the magnets immersed in ferrofluid is the theoretical basis of various application of ferrofluid. In this paper, based on the equivalent magnetic charge models and the equivalent current models of cylindrical magnets, magnetic charge image method and current image method are used to calculate the magnetic levitation force exerted on the cylindrical magnets immersed in ferrofluid respectively. The magnetic levitation force under the same conditions is calculated by the Comsol Multiphysics software according to the mechanical formula after the distribution of the magnetic field is obtained using finite element method. The magnetic levitation force is also measured experimentally, whose results are compared with the theoretical results obtained by the three methods. The analysis shows that the variation law of the magnetic levitation force and the influence by various parameters can be evaluated by the calculation with magnetic charge image method and current image method, but there is great difference between the theoretical results and the experimental results, and the greatest difference are 46% and 62% respectively. The agreement between the theoretical and the experimental results is quite good when the finite element method is used, whose greatest difference is 9%. Content Type Journal Article Pages 37-49 DOI 10.3233/JAE-2012-1428 Authors Wenming Yang, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing, China Decai Li, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing, China Xinzhi He, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing, China Qiang Li, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing, China Journal International Journal of Applied Electromagnetics and Mechanics Online ISSN 1875-8800 Print ISSN 1383-5416 Journal Volume Volume 40 Journal Issue Volume 40, Number 1 / 2012

Description: This paper proposes a novel concentrated flux interior permanent magnet (IPM) type brushless DC (BLDC) motor that replaces low-price ferrite magnets, which has similar characteristics as the conventional IPM type BLDC motor that uses expensive NdFeB magnets. To minimize the cogging torque which is a disadvantage of the proposed model, optimal designs of rotor and permanent magnet were performed. In optimal design process, the Kriging method based on the Latin hypercube sampling (LHS) and a genetic algorithm (GA) are applied due to suitability to non-linear data. Furthermore, to improve the average torque of the proposed model, the current excitation range was changed according to inductance. Through the optimal design process and the proper current excitation range, we show that the optimal model using low-price ferrite magnets has similar performance as the conventional IPM type BLDC motor using NdFeB magnets. Content Type Journal Article Pages 957-963 DOI 10.3233/JAE-2012-1565 Authors Jin-hee Lee, Department of Electronic, Electrical, Control and Instrumentation Engineering, Hanyang University, Seoul, Korea Thomas Anthony Lipo, Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, WI, USA Byung-il Kwon, Department of Electronic, Electrical, Control and Instrumentation Engineering, Hanyang University, Seoul, Korea Journal International Journal of Applied Electromagnetics and Mechanics Online ISSN 1875-8800 Print ISSN 1383-5416 Journal Volume Volume 39 Journal Issue Volume 39, Number 1-4 / 2012

Description: This paper aims to clarify time response properties of a solid polymer electrolyte (SPE) sensor. SPE film has been attracted attention in wide range of fields, and it is expected to be used as soft actuators and sensors. SPE film can reversely convert electrical energy into mechanical energy. Moreover, SPE film is lightweight, flexible, and has good workability and air-stable output. Although authors have been investigated output characteristics of an SPE sensor, time response properties of the sensor have not been inspected. In the paper, to reveal time response properties of the SPE sensor, the sensor output behaviors for several deformation velocities are measured and evaluated. Maximum voltages in the transient response and output attenuations for constant deformation are analyzed. Results show that the attenuation characteristics depend on the sensor deformation velocity, and maximum voltages in the transient response are independent of deformation velocities. Content Type Journal Article Pages 1063-1068 DOI 10.3233/JAE-2012-1579 Authors Manabu Otsuki, Graduate school of Biomedical Engineering, Tohoku University, Miyagi, Japan Takeshi Okuyama, Graduate school of Biomedical Engineering, Tohoku University, Miyagi, Japan Mami Tanaka, Graduate school of Engineering, Tohoku University, Miyagi, Japan Journal International Journal of Applied Electromagnetics and Mechanics Online ISSN 1875-8800 Print ISSN 1383-5416 Journal Volume Volume 39 Journal Issue Volume 39, Number 1-4 / 2012

Description: The characteristics in the linear induction motor (LIM) mode of new wireless energy transmission device are cleared analytically. The apparatus operates as two types of LIM with propulsion force or a linear transformer without thrust. One type of the LIM is a secondary current controlled wound type of LIM with primary winding on ground and the other is the LIM with reaction plate on ground. The paper shows the characteristics of the wound type of LIM in power running and has the onboard power transmission function even in the power running. The two-dimensional finite element method (FEM) is used for the analysis. As a result, it is cleared that the model designed for urban transit has high efficiency and high input power factor respectively more than 0.9 for the optimal control. Content Type Journal Article Pages 1035-1040 DOI 10.3233/JAE-2012-1575 Authors Nobuo Fujii, Faculty of Information Science and Electrical Engineering, Kyushu University, Fukuoka, Japan Shuhei Kanamitsu, Faculty of Information Science and Electrical Engineering, Kyushu University, Fukuoka, Japan Takeshi Mizuma, National Traffic Safety and Environment Laboratory, Tokyo, Japan Journal International Journal of Applied Electromagnetics and Mechanics Online ISSN 1875-8800 Print ISSN 1383-5416 Journal Volume Volume 39 Journal Issue Volume 39, Number 1-4 / 2012

Description: In this paper, the effects of magnetization on the rotor conductor of a written-pole motor (WPM) are analyzed and then the shape of the conductor to maximize the amount of the magnetization is designed while the magnet on the rotor is magnetized by an exciter pole. The optimization is performed with design variables that are the shape and number of the rotor bars, where an objective function is set to the amount of magnetization satisfying a constraint of the start-up time. The optimal design is verified by sequentially using a finite elements method and response surface method. Content Type Journal Article Pages 973-980 DOI 10.3233/JAE-2012-1567 Authors Seong-Cheol Park, Research and Development, Amotech, Pyeongtaek, Kyunggi-do, Korea Myoung-Hyun Choi, Department of Electrical Engineering, Kunsan National University, Jeollabuk-do, Korea Kyeong-Jin Yuk, Department of Electrical Engineering, Kunsan National University, Jeollabuk-do, Korea Byung-Taek Kim, Department of Electrical Engineering, Kunsan National University, Jeollabuk-do, Korea Journal International Journal of Applied Electromagnetics and Mechanics Online ISSN 1875-8800 Print ISSN 1383-5416 Journal Volume Volume 39 Journal Issue Volume 39, Number 1-4 / 2012

Description: This paper investigates the performance of the line start permanent magnet (LSPM) motor which needs a high efficiency characteristic in a wide operation region. LSPM motor's performance indexes, such as efficiency, motor current, load angle and synchronous torque, have complex relationship with each other according to the main and auxiliary windings distribution, and the selection of running capacitor. The output characteristics can be defined by the winding structure which is calculated by d-q equivalent circuit and finite element method. The efficiency characteristic is verified by simulation as well as by experiment on the designed LSPM motor. From the results, we show that the redesigned model considering the winding structure and capacitor matching has a wide operating region. Content Type Journal Article Pages 925-931 DOI 10.3233/JAE-2012-1561 Authors Se-Hyun Rhyu, Intelligent Mechatronics Research Center, Korea Electronics Technology Institute, Gyeonggi-do, Korea Jeong-Jong Lee, Intelligent Mechatronics Research Center, Korea Electronics Technology Institute, Gyeonggi-do, Korea Young-Kyoun Kim, Intelligent Mechatronics Research Center, Korea Electronics Technology Institute, Gyeonggi-do, Korea Byung-Taek Kim, Department of Electrical Engineering, Kunsan National University, Gunsan, Korea Dae-Kyong Kim, Department of Electrical Engineering, Sunchon National University, Sunchon, Korea Journal International Journal of Applied Electromagnetics and Mechanics Online ISSN 1875-8800 Print ISSN 1383-5416 Journal Volume Volume 39 Journal Issue Volume 39, Number 1-4 / 2012

Description: Magnetic bearings can support rotating rotors without any contacts. So it is possible to rotate a rotor at extremely high rotational speed. On the other hand, they can easily show elastic deformation with nonlinear oscillation, which is complicated and difficult to deal with. This study investigates nonlinear coupling of oscillation modes appearing in such a flexible rotor system with a magnetic bearing, by considering both the nonlinearity of the electromagnetic force and the continuousness of the rotor. First, an essential model of a rotor with an elastic shaft supported by a magnetic bearing was introduced. The numerical results indicate occurrence of internal resonance caused by the nonlinear coupling of the modes, if the ratio of their natural frequencies is 1 to 3 Experiments were also carried out and obtained results showed qualitative accordance to the numerical results. Content Type Journal Article Pages 941-948 DOI 10.3233/JAE-2012-1563 Authors Ryosuke Amano, Mechanical Engineering, Keio University, Hiyoshi, Kohoku-ku, Japan Hiroki Gotanda, Mechanical Engineering, Keio University, Hiyoshi, Kohoku-ku, Japan Toshihiko Sugiura, Mechanical Engineering, Keio University, Hiyoshi, Kohoku-ku, Japan Journal International Journal of Applied Electromagnetics and Mechanics Online ISSN 1875-8800 Print ISSN 1383-5416 Journal Volume Volume 39 Journal Issue Volume 39, Number 1-4 / 2012

Description: The paper presents an application of the topological derivative and continuum sensitivity analysis for the optimal design of the permanent magnet excited machines with the adjustable excitation. In our work we applied a topological optimization in order to find a general shape of rotor poles consisted of an iron and magnet part. An essential advantage of the proposed method is its numerical effectiveness. In order to verify results, three-dimensional models were developed and thoroughly analyzed. As presented in the comparative analysis of 3D results, the applied method lead to the significant reduction of both, the cogging torque and a level of higher harmonics in the voltage induced in the armature windings. Content Type Journal Article Pages 933-940 DOI 10.3233/JAE-2012-1562 Authors Piotr Putek, Department of Mathematical Analysis, Faculty of Engineering and Architecture, Ghent University, Ghent, Belgium Marian Slodička, Department of Mathematical Analysis, Faculty of Engineering and Architecture, Ghent University, Ghent, Belgium Piotr Paplicki, Department of Power Systems and Electrical Drives, West Pomeranian University of Technology, Szczecin, Poland Ryszard Pałka, Department of Power Systems and Electrical Drives, West Pomeranian University of Technology, Szczecin, Poland Journal International Journal of Applied Electromagnetics and Mechanics Online ISSN 1875-8800 Print ISSN 1383-5416 Journal Volume Volume 39 Journal Issue Volume 39, Number 1-4 / 2012

Description: A gyroscope motor is a precision component widely used in aerospace, aviation and other fields. Its accuracy is very sensitive to vibration. Vibration can also cause changes in the air-gap magnetic field in addition to changes due to the electromagnetic force. This paper presents a numerical simulation method for analyzing the electromagnetic characteristics of the gyroscope motor air gap subject to the coupled electromagnetic force and mechanical vibration. It analyzes the magnetic field in the gap in the axial and circumferential directions using a finite element method model, and then analyzes the magnetic characteristics of the gyroscope motor air gap subject to the coupled electromagnetic force and vibration. The method can be used to estimate the electromagnetic vibration to optimize the design of a gyroscope motor and extend its life. Content Type Journal Article Pages 949-955 DOI 10.3233/JAE-2012-1564 Authors Baokun Yang, State Key Laboratory for Strength and Vibration of Mechanical Structure, School of Aerospace, Xi'an Jiaotong University, Xi'an, Shaanxi, China Hongbing Zheng, State Key Laboratory for Strength and Vibration of Mechanical Structure, School of Aerospace, Xi'an Jiaotong University, Xi'an, Shaanxi, China Guirong Yan, State Key Laboratory for Strength and Vibration of Mechanical Structure, School of Aerospace, Xi'an Jiaotong University, Xi'an, Shaanxi, China Journal International Journal of Applied Electromagnetics and Mechanics Online ISSN 1875-8800 Print ISSN 1383-5416 Journal Volume Volume 39 Journal Issue Volume 39, Number 1-4 / 2012

Description: This paper presents the structure design and analysis of inner-rotor type axial-flux permanent magnet synchronous machines(AFPMs). The major sources of vibration in electric machines such as motors and generators are electric magnetic force distributed on both stators. The rotor suffers from unbalanced magnetic force when air gas are not symmetric on dual sides. In this paper, natural frequencies, mode shapes, and deformation were studied at normal and fault operations. Content Type Journal Article Pages 1027-1033 DOI 10.3233/JAE-2012-1574 Authors Jian Li, Department of Electrical Engineering, Dong-A University, Busan, Korea Sang-Geon Lee, Department of Electrical Engineering, Dong-A University, Busan, Korea Yun-Hyun Cho, Department of Electrical Engineering, Dong-A University, Busan, Korea Journal International Journal of Applied Electromagnetics and Mechanics Online ISSN 1875-8800 Print ISSN 1383-5416 Journal Volume Volume 39 Journal Issue Volume 39, Number 1-4 / 2012