EPE Journal Volume 04-1 
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EPE Journal Volume 04-1 - Editorial
EPE Journal Volume 04-1 - Papers



 EPE Journal Volume 04-1 - Editorial 

A New Start for the EPE Journal  [Details]
By B. Sneyers

The Editorial of the EPE Journal Volume 04 N1, "A New Start for the EPE Journal", written by Ir. Brigitte Sneyers, the Editor of EPE Association.


 EPE Journal Volume 04-1 - Papers 

Battery Operated Wheelchairs, Using 3-phase Cage Rotor Induction Machines and PWM Inverters  [Details]
By J. M. Barnard; J. D. van Wyk; W. G. Dunford

Because of cost considerations, a new approach to a battery-fed wheelchair drive system is presented. The drive employs two inexpensive 200 W 3-phase cage rotor induction machines with maximum speed of 6000 rpm. The machines are fed by two low loss, state of the art three phase PWM FET-based inverters. A simple control & differential algorithm and PWM-generation is implemented in a single INTEL 80196 microprocessor. A block diagram of the above mentioned system is shown in fig. 1. An experimental setup for dynamic drive evaluation, comprising and accurately controllable load is also reported and the characteristics of the drive illustrated experimentally.

Small Loss Series Resonant Inverter  [Details]
By K. Heumann; J. Ying

A main advantage of the series resonant inverter is its simple structure. It needs only a non-controlled rectifier as power source, because its output power can easily be changed through adjusting frequency or shifting phase of the inverter. Through calculation and experiment it is shown that by these methods, the when output power of the inverter in some range decreases, the turn-off loss increases because its turn-off current increases. This character on the one hand restricts the output capacity and frequency of the inverter, on the other hand reduces the efficiency of the equipment. In order to solve this problem, a novel control method (cycle control method), by which the turn-off current of the switch is always limited to a fairly small value, is presented. The results of simulation with PSpice and a 60 kHz 6 kW IGBT series inverter induction heating equipment demonstrate that the switches of the series resonant inverter by this conbtrol method have so small switching losses that they can work in high frequency and large capacity range.

Current and Voltage Circumstances in DC Pulse Converter Supplied from a Source with Great Inductance  [Details]
By V. Racek

A DC pulse converter supplied by a source with inductivity, (a usual case in electric traction) must have an entry filter (Fig. 1). In this paper a theoretical analysis of physical phenomena in such a converter is presented and current and voltage waveforms in the system converter - filter are derived. (Fig. 5). From the results of these analyses relations for preliminary drafts elements of circuit-filter choke (Lf), capacitor (C) and smoothing choke of the motor (Lm) is derived. These parameters are determined under simplifying conditions and the limits of applicability of such results are shown. By reason of making the parameters more accurate a method of computer simulation is used, where the preliminary determined parameters of the elements as starting dates are used. The results of the simulation experiments (Fig. 9 - 12) give a quick solution, which secures to achieve the prescribed ripple of the motor current, of the input current and of the filter capacitor voltage.

Current Developments in High-Power Thyristors  [Details]
By H. Mitlehner; H.-J. Schulze

One way of increasing the reliability of thyristor valves is to reduce the number of devices required for a high blocking voltage. An essential precondition for this is the introduction of new technologies which allow the total power loss of high-blocking thyristors to be kept within reasonable limits. The drive circuitry can be further simplified by directly integrated light triggering and overvoltage protection into the thyristor.

Semiconductor Materials for High Temperature Power Devices  [Details]
By M. L. Locatelli; S. H. Gamal; J. P. Chante

The use of silicon as the basic semiconductor for power electronic sets a limitation for the rise in device operating temperature. The great increase in leakage currents is a major obstacle for the rise in junction temperature. To avoid this drawback, wide bandgap semiconductors must be considered. Among them, silicon carbide is a promising material thanks to its physical properties more suitable for power applications than those of silicon or gallium arsenide. Moreover its technological progress makes it more and more industrially applicable, which is not yet the case for diamond.