A novel active resonant snubber for single switch unity power factor three-phase diode rectifiers

摘要

A new active feed-forward snubber for conventional three-phase PWM (pulse width modulated) boost rectifier using single switch operated in discontinuous conduction input current mode (DCM) is proposed. It is a resonant circuit consisting of a switch and passive components and it ensures that the main boost switch will be switched under zero-voltage (ZV) condition. Also, the boost diode operates under soft switching condition. Since the snubber circuit is a resonant circuit, the auxiliary switch itself has a soft turn-on and turn-off, resulting in reduced switching losses and electromagnetic interference (EMI). Performance of the converter circuit is predicted by simulating it on SABER. A laboratory prototype delivering 1 kW power at 245 Volts from 86.6 Vrms (L-L) is designed and developed. The simulation results obtained are verified experimentally.