A Simple Structure of Auxiliary Resonant Commutated Pole SiC-Based Soft-Switching Inverter

In this article, an auxiliary resonant commutated pole soft-switching inverter with a simple structure of the auxiliary circuit is proposed. Using SiC MOSFET with low turn-off loss characteristic, this design removes all resonant capacitors and two auxiliary diodes in each phase of the original topology, and the resonant current in the auxiliary circuit approaches the load current, diminishing current stress and conduction loss. The modulation strategy employed in this topology enables the generation of driving signals to be simple and easily implementable. According to the proposed modulation strategy, the circuit working modes are analyzed in the presence of parasitic capacitor, the performance among different schemes is compared, and parameter design is completed. Finally, an experimental platform for a soft-switching motor drive with a switching frequency of 40 kHz is built to validate the theoretical analysis. Experimental results show that the proposed scheme can surpass the hard-switching motor drive system in efficiency under heavy load, achieving a peak efficiency of 96.922% at 3.0 kW.