The Loss Analysis and Efficiency Optimization of Power Inverter Based on SiC mosfets under the High-Switching Frequency

Due to its low loss and high switching frequency, the silicon carbide metal oxide field effect transistors (SiC mosfets) are more suitable as switching devices in power inverter for electric vehicles. However, the power losses of power inverter would be dramatically increased with the rise of switching frequency, which would result in the limitation of using the high switching frequency performance of SiC mosfet. In view of this case, this article would systematically analyze the power losses distribution of power inverter and further optimize its efficiency under the high switching frequency. It is demonstrated that the power losses of power inverter are linearly increased with the rise of switching frequency, which is mainly caused by the switching losses of mosfet chips increment. Based on this situation, an adaptive discontinuous pulsewidth modulation (ADPWM) is proposed to optimize the power inverter efficiency under the high switching frequency, which can effectively reduce the total power losses of power inverter and improve its efficiency compared with that of the conventional PWM strategies. Finally, the power losses and efficiency of power inverter with the proposed ADPWM strategy is verified by the experimental results.