Control Schemes for Auxiliary Switches of Three-Phase PWM Resonant Snubber Inverters

Control schemes for auxiliary switches of PWM controlled three-phase resonant snubber inverters (RSIs) are proposed. The control schemes proposed in this paper are based on a conventional PWM technique. To avoid zero voltage switching lost conditions, the conventional PWM technique is modified in the proposed schemes. The proposed control schemes are so simple that they are suitable for digital control. In this paper, a CPLD (Complex Programmable Logic Device)-based control IC, which realizes the proposed control schemes, for three-phase auxiliary RSIs is also proposed and implemented. The IC generates gate signals for the main and auxiliary devices of the three-phase RSI based on the proposed control schemes. The effectiveness of the proposed control schemes was verified through experiments. As a result, ZVS (Zero Voltage Switching) turn-on at the main devices was achieved and a smooth sinusoidal output current was obtained by use of the control IC. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(4): 57–67, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20125