PCIM 2018 Tutorial

Modern Soft Switching Technologies

Schedule: Monday, 04.06.2018, 09:00 – 17:00 hrs
Room: Arvena Park Hotel Nuremberg, Görlitzer Str. 51, 90473 Nuremberg

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The goal of this tutorial is to present the modern soft switching technologies as an avenue to increase the efficiency and power density in power convertors.

Soft switching topologies have become popular in many applications in the last thirty years. Though we have such a long tradition in soft switching technologies, some of these have added too much complexity and their practical use becomes questionable. In addition, some of the traditional soft switching topologies address just the soft switching on the primary side and not the soft switching in the secondary. Many of these technologies are novel and never presented before. In many of these novel technologies, zero voltage switching is accomplished by using the energy contained in the parasitic elements which traditionally were dissipated.

The modern soft switching technologies which will be presented in the tutorial do provide true soft switching. In true soft switching technology, the primary switching devices turn on at zero voltage and the secondary switching devices turn off at zero current. There is no ringing or spikes across any of the switching devices during operation; and this is done without the use of any snubbers. These technologies are a derivation of the classical topologies, such as flyback, boost, two transistors forward, half bridge and full bridge with some minor modification and most of them are using intelligent control to obtain true soft switching.

The goal of the modern soft switching technologies is to have a simple and low-cost hardware and an intelligent control designed to minimize the losses under different operating conditions. Though the tutorial will be focused on the modern topologies, a section is dedicated to magnetics. In the quest for efficiency above 99%, the magnetic technology plays a very important role. In some applications such as modern soft switching flyback some of the energy for soft switching is extracted from the parasitic elements of the transformer. A detailed power dissipation analysis in several applications will highlight the need for magnetic optimization. In spite of the significant progress in the semiconductor industry, the technology in magnetics lags behind. The tutorial will describe the impact of the parasitic elements in the magnetics in optimizing the performance of the power converters. Presently we are reaching 99% efficiency in PFC and DC-DC converters by using these modern soft switching technologies, optimized magnetics and intelligent control. The developments in semiconductor technology such as GaN and SiC did help us to further improve the efficiency exceeding the 99% in some applications.

The tutorial will present also the impact of intelligent power processing in optimizing the efficiency and even in converting a traditional hard switching topology into a soft switching topology.

The presentation will be highlighted with design examples and experimental results such as 99%+ efficiency PFC with power densities above 1000W/in3, and 99% efficiency isolated DC-DC Converters.