ANALYSIS OF A QUASI-RESONANT CIRCUIT FOR SOFT-SWITCHED INVERTERS

This paper presents an analysis of a quasi-resonant circuit for soft-s witched inverters. The quasi-resonant circuit provides zero-voltage in stants for zero-voltage inverter switching by pulling down the de link voltage momentarily to zero without increasing the peak value of the nominal de link voltage. Switches in the quasi-resonant circuit can al so be turned off at zero current/voltage conditions, The proposed circ uit allows creation of zero voltage conditions for inverter soft-switc hing under loaded and no-load conditions, The operating principle of t his circuit is explained, and the analysis of each operating mode is d escribed, Design criteria for achieving zero voltage switching are der ived from the general mathematical analysis. Operation of the circuit has been verified by PSPICE simulation and experiments.