In traditional OBC, the PFC switching frequency is usually no more than 100kHz, while in matrix converter customers are pursuing 200kHz to 500kHz to increase power density. In higher switching frequency applications, SiC or GaN is used to replace Si based power switches. For traditional Si based power switches, the short-circuit withstand time can exceed 10us. However, this value drops to less than 2us in the case of SiC based power switches and further decreases to be less than 1us in GaN based power switches.

The key factor affecting the short-circuit withstand time is the thermally induced catastrophic failure. The power switch is subjected to high voltage and high current during a short-circuit scenario, which leads to enormous instantaneous power dissipation and rapid temperature increase. Generally, GaN based power switches have higher current density, resulting in high power-density and rapid temperature increases during short-circuit conditions.

Therefore, for matrix converters, the OC response must be faster than traditional OBC because of the characteristics of power switches.