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  • Articles  (3)
  • Springer  (3)
  • Elsevier
  • 1990-1994  (3)
  • Electrical Engineering, Measurement and Control Technology  (3)
  • 1
    Publication Date: 1990-01-01
    Print ISSN: 0948-7921
    Electronic ISSN: 1432-0487
    Topics: Electrical Engineering, Measurement and Control Technology
    Published by Springer
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Electrical engineering 74 (1990), S. 3-14 
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Übersicht Neue Leistungshalbleiter-Bauelemente, IGBT's und ein bipolarer Transistor mit Feinstruktur, werden für den Einsatz in schnell schaltenden PWM Wechselrichtern untersucht. Die Bauelement-Daten liegen im Bereich 1000 V/100 A. Entsprechend erreichen die Wechselrichter Leistungen von einigen zehn Kilovoltampere. Gegenstand des Vergleiches sind Ansteueraufwand, Durchlaß- und Schaltverluste, Schaltgeschwindigkeit und Überlastbarkeit. Beschrieben wird eine automatisierte Testeinrichtung für die integrale Messung von Schaltverlusten in Abhängigkeit von der Schaltfrequenz. Ein Ergebnis ist, daß IGBT's einfache Ansteuerschaltungen benötigen. Dagegen liegt ihre Betriebsfrequenz bei Nennstrom niedriger als bei einem bipolaren Junctiontrasistor mit Feinstruktur. Allerdings ist bei dem Feinstrukturtransistor die Ansteuerung aufwendiger.
    Notes: Contents New power devices — IGBT's and a bipolar transistor with cellular structure are investigated for applications in fast switching PWM inverters. Device ratings are in the 1000 V/100 A range, inverter power reaches up to some ten kilovoltamperes, respectively. Subjects of the comparison are the gate drive requirements, conduction and switching losses, switching speed and overload capability. An automated test equipment for the integral measurement of power losses in function of the switching frequency is described. As a result IGBT's need simple gate drive circuits, but operating frequency at rated current is lower, than that of a bipolar junction transistor with cellular structure. However the base drive circuit of a cellular transistor is more complex.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Optical and quantum electronics 22 (1990), S. S107 
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract Sensitization of the fluorescence of Er3+ in fluoride phosphate glass containing up to 20 mol% phosphates by codoping with Cr3+ and Yb3+ is shown. The low order of ligand field strength for Cr3+ (Dq/B=2.04) results in broad Cr3+ fluorescence overlapping the Yb3+ absorption. The electronic energy transfer efficiency approaches 100%. Deviations of donor decay from the Förster law are interpreted in terms of the inhomogeneously acceptor distribution. The electronic energy transfer efficiency of Yb3+ → Er3+ reaches a maximum value of 75% for glasses containing 20 mol% phosphates. The transfer is shown to be migrationally accelerated by means of GAF-LAF-FB theory. From Judd-Ofelt parameters a stimulated emission cross-section for the transition4I13/2 →4I15/2 of Er3+ of 6.2×10−20 cm2 is derived. The c.w. laser action of Er3+ by Cr3+ excitation and double-step energy transfer is shown. The output is tuned continuously from 1536 to 1596 nm. Flashlamp pumping is also shown.
    Type of Medium: Electronic Resource
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