The loss calculation of RCD snubber with forward and reverse recovery effects considerations

This paper addresses the problem of turn-off and turn-on performances of a RCD snubber circuit in high power inverter that works with insulated gate bipolar transistor (IGBT). The RCD snubber circuit turn-off and turn-on dynamics, forward and reverse recovery effects of the associated freewheeling and snubber diodes, and corresponding snubber losses are analyzed. Voltage impacts occur across the snubber resistor due to the snubber diode's forward and reverse recovery effects, which bring in additional snubber losses. The turn-on current rising rates have two parts due to the anti-parallel free-wheeling diode (FWD) reverse recovery current that will influence the RCD loss. Moreover, the snubber has the same clamping effect as turn-off due to the anti-parallel FWD's reverse recovery current. In addition, the proposed analysis was experimentally verified, the snubber loss are presented and discussed in the paper. Moreover, a well-designed temperature measurement is proposed to evaluate the loss.