A high efficiency inverter based on SiC MOSFET without externally antiparalleled diodes

This paper analyzes a high efficient SiC MOSFET based inverter without externally antipa-rallelled diodes. To this end, steady-state performances of MOSFET channel and its body diode are demonstrated; proper control and modulation technique is applied to realize synchronous rectification of the inverter and to minimize the conduction loss of body diodes. Power loss analysis of the inverter under various junction temperatures is performed. Calculated results show it is unnecessary to antiparallel external diodes for the less than 0.15% efficiency improvement since external diodes will inevitably increase the system volume and harm the power density. At last, a 10 kW SiC MOSFET based prototype is built. Full load efficiency greater than 98% is achieved. Experimental results show that the three phase inverter exhibits high efficiency under various working conditions even without antiparalleled diodes. By removing the external diodes, system volume and cost of the inverter can be reduced and power density improved. This paper shows the possibility of utilizing body diodes and provides references for tradeoff making between power efficiency and power density of the inverter.