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F.C. Zach

Bio: F.C. Zach is an academic researcher from University of Vienna. The author has contributed to research in topics: Three-phase & Power semiconductor device. The author has an hindex of 15, co-authored 31 publications receiving 1443 citations.

Papers
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Journal ArticleDOI
07 Oct 1990
TL;DR: In this paper, the authors explore the dependency of the conduction losses of a bridge leg of a PWM power converter system with a high pulse rate on the shape of the phase modulation functions.
Abstract: The authors explore the dependency of the conduction losses of a bridge leg of a pulsewidth modulation (PWM) power converter system with a high pulse rate on the shape of the phase modulation functions. This is done for modulation methods that are optimized with respect to minimum harmonic current RMS values. The results are compared to the results gained for simple sinusoidal modulation. Besides conduction losses, the switching losses of the electric valves are calculated. The main topic is the determination of those power loss components of a PWM converter system that can be (besides the harmonic losses) influenced by the modulation method selected. As the calculations show, these modulation methods allow a significant increase of the effective switching frequency. The optimal modulation as calculated leads to a reduction of the harmonic power loss in the upper modulation region. Furthermore, due to the frequency modulation the spectrum is spread out to a wider frequency band as compared to operation with constant pulse frequency. >

571 citations

Proceedings ArticleDOI
03 Mar 1996
TL;DR: In this paper, the authors developed guidelines for the practical application of a new power module (IXYS VUM25-E) realizing a bridge leg of a three-phase/switch/level PWM (VIENNA) rectifier system with low effects on the mains.
Abstract: The development of guidelines for the practical application of a new power module (IXYS VUM25-E) realizing a bridge leg of a three-phase/switch/level PWM (VIENNA) rectifier system with low effects on the mains is discussed. The inner circuit structure of the power module is formed by a bidirectional bipolar switch and of two free-wheeling diodes. In a first step the switching losses of the power MOSFET and of the free-wheeling diodes are determined by measurement in dependency on the switched current for characteristic values of the junction temperature. The isolated driving stage of the MOSFET is designed for minimum switching losses considering the occurring switching overvoltages and the ringing between the parasitic circuit elements. The conduction losses of the semiconductor elements are calculated directly via simple analytical approximations of the mean and rms values of the device currents. Based on the knowledge of the dependency of the main loss contributions of the semiconductors of the power module on the operating parameters (mains voltage, output voltage, heat sink temperature and switching frequency) the thermally maximum allowable mains current amplitude is calculated. Furthermore, for different switching frequencies an overview over the power loss contributions of the semiconductor elements is given. Also, the reduction of the efficiency caused by the total semiconductor losses is determined. Finally, the overall efficiency of a PWM (VIENNA) rectifier system realised by using the IXYS VUM25-E module is estimated and further possible developments of this module are discussed.

172 citations

Journal ArticleDOI
20 Jun 1993
TL;DR: In this paper, the low frequency harmonic distortion of the mains current of a three-phase single-switch discontinuous-mode boost-rectifier is calculated based on application of space vector calculus and on substitution of discontinuous time shapes within a pulse period by quasicontinuous time shape.
Abstract: In this paper the low frequency harmonic distortion of the mains current of a three-phase single-switch discontinuous-mode boost-rectifier is calculated. The system analysis is based on application of space vector calculus and on substitution of discontinuous time shapes within a pulse period by quasicontinuous time shapes. The quasicontinuous time shapes are defined by averaging over the pulse period. The dependency of the shape of the input currents on the voltage transformation ratio is given for various control methods in analytical form. The results of the theoretical analysis are verified by digital simulation and by measurements on a laboratory model. A good consistency of the results has been found. >

139 citations

Journal ArticleDOI
02 Oct 1993
TL;DR: In this paper, the peak, mean, and RMS values of the component currents of a three-phase single-switch discontinuous inductor current mode boost rectifier are calculated analytically.
Abstract: In this paper the peak, mean, and RMS values of the component currents of a three-phase single-switch discontinuous inductor current mode boost rectifier are calculated analytically. The values are given in rated form in dependency on the output power and on the ratio of output voltage to the amplitude of the mains voltage. Furthermore, the influence of the voltage transfer ratio on the shape of the mains currents and on the power factor of the system is analyzed. The theoretical analysis is verified by digital simulation and a good consistency is achieved. Finally, the approach of the converter dimensioning based on the graphical representation of the calculation results is described and illustrated using a specific example. The correctness of the dimensioning is verified by measurements on a laboratory model. >

87 citations

Journal ArticleDOI
TL;DR: In this article, a three-phase single-switch AC-DC flyback converter system is presented, which operates in the discontinuous mode, and the simple structure of its power and control circuit, low mains current distortion, and resistive fundamental behavior, as well as the high-frequency isolation of the controlled output voltage, have been pointed out.
Abstract: In this paper, a new three-phase single-switch AC-DC flyback converter system is presented. The system operates in the discontinuous mode. The simple structure of its power and control circuit, low mains current distortion, and resistive fundamental behavior, as well as the high-frequency isolation of the controlled output voltage, have to be pointed out. Besides the analysis of the stationary operating behavior, the dependencies of the peak values, average values, and rms values of the device currents, and of the maximum blocking voltages across the power electronic devices on the circuit parameters, are given as analytic approximations. The theoretical analysis is verified by digital simulation. >

70 citations


Cited by
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Journal ArticleDOI
TL;DR: The most important topologies like diode-clamped inverter (neutral-point clamped), capacitor-Clamped (flying capacitor), and cascaded multicell with separate DC sources are presented and the circuit topology options are presented.
Abstract: Multilevel inverter technology has emerged recently as a very important alternative in the area of high-power medium-voltage energy control. This paper presents the most important topologies like diode-clamped inverter (neutral-point clamped), capacitor-clamped (flying capacitor), and cascaded multicell with separate DC sources. Emerging topologies like asymmetric hybrid cells and soft-switched multilevel inverters are also discussed. This paper also presents the most relevant control and modulation methods developed for this family of converters: multilevel sinusoidal pulsewidth modulation, multilevel selective harmonic elimination, and space-vector modulation. Special attention is dedicated to the latest and more relevant applications of these converters such as laminators, conveyor belts, and unified power-flow controllers. The need of an active front end at the input side for those inverters supplying regenerative loads is also discussed, and the circuit topology options are also presented. Finally, the peripherally developing areas such as high-voltage high-power devices and optical sensors and other opportunities for future development are addressed.

6,472 citations

Journal ArticleDOI
TL;DR: Current control techniques for three-phase voltage-source pulsewidth modulated converters, including bang-bang (hysteresis, delta modulation) controllers and predictive controllers with on-line optimization are reviewed.
Abstract: The aim of this paper is to present a review of current control techniques for three-phase voltage-source pulsewidth modulated converters. Various techniques, different in concept, have been described in two main groups: linear and nonlinear. The first includes proportional integral (stationary and synchronous) and state feedback controllers, and predictive techniques with constant switching frequency. The second comprises bang-bang (hysteresis, delta modulation) controllers and predictive controllers with on-line optimization. New trends in current control-neural networks and fuzzy-logic-based controllers-are discussed, as well. Selected oscillograms accompany the presentation in order to illustrate properties of the described controller groups.

2,086 citations

Journal ArticleDOI
TL;DR: This paper presents an exhaustive review of three-phase improved power quality AC-DC converters configurations, control strategies, selection of components, comparative factors, recent trends, their suitability, and selection for specific applications.
Abstract: Solid-state switch-mode rectification converters have reached a matured level for improving power quality in terms of power-factor correction (PFC), reduced total harmonic distortion at input AC mains and precisely regulated DC output in buck, boost, buck-boost and multilevel modes with unidirectional and bidirectional power flow. This paper deals with a comprehensive review of improved power quality converters (IPQCs) configurations, control approaches, design features, selection of components, other related considerations, and their suitability and selection for specific applications. It is targeted to provide a wide spectrum on the status of IPQC technology to researchers, designers and application engineers working on switched-mode AC-DC converters. A classified list of more than 450 research publications on the state of art of IPQC is also given for a quick reference.

1,691 citations

Book ChapterDOI
01 Jan 2013
TL;DR: This chapter gives a description and overview of power Electronic technologies including a description of the fundamental systems that are the building blocks of power electronic systems.
Abstract: This chapter gives a description and overview of power electronic technologies including a description of the fundamental systems that are the building blocks of power electronic systems. Technologies that are described include: power semiconductor switching devices, converter circuits that process energy from one DC level to another DC level, converters that produce variable frequency from DC sources, principles of rectifying AC input voltage in uncontrolled DC output voltage and their extension to controlled rectifiers, converters that convert to AC from DC (inverters) or from AC with fixed or variable output frequency (AC controllers, DC–DC–AC converters, matrix converters, or cycloconverters). The chapter also covers control of power converters with focus on pulse width modulation (PWM) control techniques.

1,152 citations

Journal ArticleDOI
01 Aug 1994
TL;DR: In this paper, the authors present a detailed overview of the switching functions used in power converters, ranging from simple averaging schemes to involved methods of real-time optimization, which can be found in the literature.
Abstract: The efficient and fast control of electric power forms part of the key technologies of modern automated production It is performed using electronic power converters The converters transfer energy from a source to a controlled process in a quantized fashion, using semiconductor switches which are turned on and off at fast repetition rates The algorithms which generate the switching functions-pulsewidth-modulation techniques-are manifold They range from simple averaging schemes to involved methods of real-time optimization This paper gives an overview >

1,041 citations