A Passive Soft-Switching Snubber With Energy Active Recovery Circuit for PWM Inverters

Abstract

A passive soft-switching snubber with energy active recovery circuit (PSS-EARC) for pulse width modulation (PWM) inverters is proposed in this paper. The PSS-EARC recovers the buffering energy of the snubber inductors and capacitors back to the input voltage source while achieving passive softswitching, so as to improve the inverter efficiency. In this paper, the configuration and operation principle of the PSS-EARC are analyzed and studied in detail firstly. Comparing with the traditional energy passive recovery circuit, the PSS-EARC avoids the circulating current issue by employing the auxiliary switches. Because the control of auxiliary switches is simple and independent, it is also benefit to the integration of auxiliary circuits. Moreover, in three-phase inverter application, the EARC is shared by three bridge-legs, which may further simplify the circuit. Finally, a 10kW three-phase inverter with the PSS-EARC is built. The experimental results demonstrate the validity and superiority of the proposed circuit. INDEX TERMS Energy active recovery, inverter, passive soft-switching, switching loss.