A Hard-Switching Loss Calculation Method for SiC MOSFETs Without Current Sensors

This paper presents a hard-switching loss calculation method for SiC MOSFETs without current sensors. Firstly, the concept that the commutation process of the complementary devices in different topologies is analogous to occurring within a half-bridge circuit is discussed. Then, the switching process of SiC MOSFETs is analyzed in detail based on the half-bridge circuit. The proposition that the trend of current changes can be inferred from the characteristics of voltage changes is put forward. The measured voltage and the predicted current waveforms are fitted with time-domain expressions in order to calculate the switching losses. Finally, the total losses obtained by the proposed calculation method are verified to be within 5% deviation from the actual losses.