New Lossless Turn-On and Turn-Off (Snubber) Networks for Inverters, Including Circuits for Blocking Voltage Limitation

Transistorized pulsewidth modulated (PWM) inverters require careful dimensioning of turn-on and turn-off circuits in order to minimize switching loss in the power transistors. New lossless circuits are described. In particular the turn-off circuits show a highly reduced part count compared to circuits known from the literature. The turn-on circuits apply energy recovery. Furthermore, due to a special circuit the voltage across the power transistor is strictly limited. This is important especially due to the usually low voltage blocking capability of high-current power transistors.