Research of RCD clamp snubber for high power combined three-phase inverter

The new problems when applying a conventional resistor-capacitor-diode (RCD) clamp snubber to the high power combined three-phase inverter system are investigated. In high power application, the existence of parasitic induction in dc bus makes an additional energy loss on the RCD clamp snubber. The particular topology of combined three-phase inverter makes this situation worse. In this paper, a combined three-phase inverter model with equal parasitic induction is built, the transient analysis is presented to show the effect of parasitic induction on the RCD snubbers, and the relation between the additional energy loss and the parameters of inverter is deduced. The results of the analysis are verified both by the simulation of SABER and a 300 kVA prototype with the combined three-phase configuration.