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EPE Journal Volume 05-2 - Papers
EPE Journal Volume 05-2 - Editorial
By B. Sneyers
The Editorial of the EPE Journal Volume 05 N°2, "After the fire...", written by Ir. Brigitte Sneyers, the Editor of EPE Association
EPE Journal Volume 05-2 - Papers
By T. H. Abdelhamid; M. K. Darwish; P. Mehta; A. L. Mohamadien; M. S. Abo-Elela
This paper introduces a new high-frequency (HF) link on-line Uninterruptible Power Supply (UPS) configuration based on one HF transformer with three windings. The HF link is established using a resonant inverter during normal operation of the UPS and a sinusoidal pulse-width modulation (SPWM) inverter during mains failure. A cycloconverter is used to construct the low-frequency output voltage. Another configuration of the system is also presented such that the system becomes more compact and flexible where the switch-mode operation of the SPWM inverter is avoided by replacing it with a resonant one. In this case, the two inverters are integrated into only one HF resonant inverter and the output is constructed and controlled using a SPWM cycloconverter. The choice of the switching frequency as well as the HF transformer material are investigated. Simulation of the UPS circuit was carried out and verified with experimental results for a 500VA, 20kHz link frequency.
By C. Blanco Viejo; M. Angel Pérez García; M. Rico Secades; J. Uceda
The delay line of a travelling wave tube amplifier (TWT) needs a high DC voltage. A power converter with high transformation ratio is necessary to obtain high output voltage from low input voltage. As a result, a large number of turns is necessary for secondary windings and large leakage inductane and large parasitic capacitor appear. Thus, it is usual to design resonant converter to include both leakage inductance and capacitance in the power topology. The present paper presents the design of a high voltage power supply for the delay line of a TWT using a resonant converter. All elements of the power supply (high voltage transformer, rectifier, filter and control) are designed taking high voltage and high frequency problems into account.
By A. Zuckerberger; G. Wild; J. Gabbay; J. Eichmeier
An electronic ballast circuit operated at unity power factor based in a parallel resonant topology (Fig. 1) equipped with a field controlled thyristor is presented. The operation of the circuit is analyzed and its design rules are specified. The proposed topology is simulated in Spice and a laboratory prototype is realized. Good agreement between the predicted behaviour and measurements was observed. The proposed topology can be employed, in a broad range of application: power supplies, battery chargers and home appliances.
By X. Pierre; J. P. Cambronne
The advantages of PWM controlled rectifiers on phase controlled ones are well known. So, in order to obtain a performant d.c. source from a three-phase rectifier, two PWM structures are generally used. The comparison of PWM voltage and current structures is presented in this paper. First, their working principles and topologies are reminded, then, their whole operating points diagram, in a (P, Q) frame, are studied in the case of active and passive loads. This allows to perfectly control and optimal trajectory of the operating points defined for an application. It appears that, even though, these diagrams are nearly the same, the voltage structure is suitable for high impedance loads, whereas the current structure requires low ones. In the case of passive loads, an example of dimensioning compares their transferable power, while considering their required filtering elements, and defines their specific applications.