EPE Journal Volume 04-3 
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EPE Journal Volume 04-3 - Editorial
EPE Journal Volume 04-3 - Papers



 EPE Journal Volume 04-3 - Editorial 

EPE '95 in Sevilla, One more year to go!  [Details]
By B. Sneyers

The Editorial of the EPE Journal Volume 04 N3, "EPE '95 in Sevilla, One more year to go!", written by Ir. Brigitte Sneyers, the Secretary General of EPE Association.


 EPE Journal Volume 04-3 - Papers 

New Driver Stage for Voltage-Controlled Components with Integrated Short-Circuit Protection  [Details]
By S. Konrad

Starting from the turn-off characteristic of the IGBT, the importance of protection against overvoltages is developed in the present article. A comparison of the active and passive protection concepts customary up to now illustrates the advantages and disadvantages of these measures with regard to integrability and reliability. A new active protection concept for voltage controlled components on the basis of an IGBT is presented. The outstanding feature is its good integrability. The critical time slot resulting from the operation of most active protective measures is avoided. The operability and reliability of the protective measure can be demonstrated with the aid of measurements.

Driving and Protecting Large Die IGBT and MOS Power Devices  [Details]
By S. Ochi

Today's smart IC gate drivers from various manufacturers simplify the design tasks facing the power systems engineers. The increased performance with greater reliability possible with the smart IC gate drivers cannot be ignored. For example, the almost instantaneous (within 200 ns) local shutdown available from a smart IC gate driver can easily protect high gain IGBT devices which can self destruct within 2 s [1]. Output feedback current sensors or fuses just aren't fast enough to protect these high gain IGBTs. The importance of proper drive and protection of large die size, high power discrete MOSFETs and IGBTs cannot be overemphasized. Modern single die discrete IGBTs can block up to 1400 V and conduct over 1800 A during a short circuit condition - over 2.5 MW of power dissipation in a little less than 6.5 cm!

Soft Switching for MW Solid-State Broadcast Transmitters  [Details]
By L. Linguet; F. Forest; P. de Boisriou

A new amplitude modulation strategy, suitable to solid-state RF transmitters (entirely transistorized) and operating in MW (Medium Wave: 530 kHz - 1.6 MHz), is presented. Unlike current solutions used in broadcastings, this modulation strategy provides a simple and effective answer to customer requirements in terms of cost and reliability. Amplitude modulation strategies used in working solid-state transmitters are presented first, then the principle of the new strategy is described. It is based on the phase-shifting of transmitter power amplifier control signals. However, this phase-shifting induces special switching modes which have to be studied. These switching modes are detailed as are their effects on the power amplifier's reliability and efficiency. This leads to am optimization of the power amplifiers and to the definition of a modulation strategy for high-frequency signals (over 1 MHz). A practical implementation with several power amplifiers is described. Efficiency and distortion measurements are given. The high-quality results highlight the interest in using phase-shifting control to realize a low cost, accurate and reliable amplitude modulation.

Commutation Types in Resonant Evolution Converters (I)  [Details]
By M. Hernando; M. Rico; V. Garca; J. Sebastian

The first part of this study offers a unified criterion to classify resonant converters, according to characteristics derived from a block diagram of a generic resonant converter. Therefore, the terms "resonant evolution" and "resonant commutation" are introduced in order to centre the rest of the research on resonant converters with resonant evolution. When Resonant Evolution Converters are studied, it is interesting to know the types of commutations they have. Therefore, commutation types in both voltage and current fed resonant converter are analyzed. A method to evaluate the commutation losses is proposed and in certain cases, the use of capacitive snubber is justified together with its selection criterion.
In Resonant Evolution Converters, two commutations can be found in a semi-cycle of switching. Once their type is known it is easy to define zones where the converter works with interchange of energy between the primary input source and the load, and zones without this interchange. These areas will be shown for three different converters, together with other experimental and simulation results.

Part II of this paper can be found in EPE Journal Volume 1994-4.

Sliding Mode Controlled Inverter with Switching Optimization Techniques  [Details]
By M. Carpita

In the paper two sliding mode controlled inverter for fixed frequency AC power supply are discribed. After a brief review of the sliding mode control theory, the way to obtain a switching frequency optimisation technique will be described for both inverters. The output transformer saturation problems will be described too. Simulation results are presented. In the last part of the paper the hardware implementation of the control and some experimental results relevant to a single phase, 5 kVA, 110 Vdc, 220 Vac, 50 Hz, and a three-phase 30 kVA, 350 Vdc, 380 Vac, 50 Hz IGBT inverters will be presented.