A high efficiency two-phase interleaved inverter for wide range output waveform generation

High voltage (3.3kV) SiC MOSFET devices enable high power density power conversion with fast switching and acceptable switching losses. The combination of fast switching device and soft-switching, which eliminates the losses of the turn on or off transition and limits the di/dt and dv/dt, becomes more important with high voltages. This paper presents a two-phase interleaved inverter which can achieve zero voltage switching (ZVS) operation for very wide output range with different voltage and current waveforms. The ZVS is realized without any additional active switches or passive components. ZVS is obtained with a phase-shift angle modulation scheme changing according to the load to minimize ripple current for all cases. It results in the lowest inductor RMS current, achieving ZVS at each load, and therefore high efficiency. The circuit operation and the impact of the phase-shift angle are described in details and the feasible ZVS range is analyzed. The analysis and design have been verified with simulation results. A 2.1kV H-bridge inverter with 3.3kV SiC MOSFETs was built and tested.