Guest Editorial

Power Electronics is one of the most fast-changing fields in Electrical and Electronics Engineering. As a field at the intersection of classical industrial applications for the electrical distribution system with the most up-dated electronics circuits, Power Electronics has known a rapid progress in the last years. Much research is devoted to answer tough demanding standards and industry needs; the today power supplies have to operate with a high efficiency in order to save energy. They must not pollute the electrical system with undesirable harmonics. They have to provide high load current, at low voltage, with fast transient response for the last generation of computers. And the list of applications is much longer.

For answering the industry requests, new topologies of DC-DC and power-factor-correction converters have to be developed. The first chapter is devoted to the latest research in this field: a new voltage regulator (VRM) operating at 1.8 MHz is presented. New AC-DC power factor correctors and inverters, with soft-switching for reducing the switching losses are then described. How to realize a fully monolithic integration of the power converter in order the miniaturize the power supply at the level of all the other electronic equipments is discussed in the last paper of the chapter.

The power electronic circuit can be seen in a dual way: as a provider of controlled energy to other electrical consumers and as a complex circuit by itself, to be analyzed, designed, and optimized.

New analysis methods, dynamic analytical and discrete models of the power converters, new simulation methods of the transient behavior of the converters, and other circuit theory developments in power electronics make the object of the second chapter.

Many control methods have been proposed for the complex power electronics circuits. New state-of-the-art developments are given in the third chapter: alternated duty-cycle control, randomized PWM, new applications of the sliding-mode control, fuzzy control, adaptive neuro-fuzzy inference control, a modified torque control, etc.

Problems related to industrial applications in the field of electrical drives and switched motors are presented in the papers of the fourth chapter.

Special topics, like a new generator of current pulses, acoustic resonance, piezoelectric transformer, implementation of an integrated inductor, design of igniters for electronic ballasts of HID lamps can be found in the concluding chapter.

We'd like to thank all the contributors to this special issue for their fine works. We hope that the implication of researchers of first hand of all over the world for realizing this special issue of our institute journal will serve as the basis for a deeper, further collaboration with the Power Electronics group of HAIT.

Boris Axelrod, Yefim Berkovich, Adrian Ioinovici -

Guest Editors