Smooth control of low-frequency junction temperature fluctuation for SiC MOSFET based on combined regulation methods

Inhalt:
SiC MOSFET is a typical representative of wide-bandgap semiconductor power devices, and the reliability research is of great significance. The operating reliability of a power device is closely related to its junction temperature. The severe fluctuation of the junction temperature will cause the device to experience greater thermal stress and cause the fatigue failure problem. Therefore, active thermal control of the device to reduce or smooth the junction temperature fluctuation can effectively improve the operating reliability of the device. Based on the special physical structure of SiC MOSFET, this paper first proposes a method of active thermal management of the device by adjusting the dead time to change its body diode loss, and further combining several methods of driving voltage adjustment and switching frequency adjustment to actively manage the junction temperature of the device. The simulation results show that the proposed junction temperature control strategy can improve the shortcomings of the single adjustment method, effectively reduce the low-frequency junction temperature fluctuations, thereby reducing the thermal stress during the operation of the device, improving the reliability of the device operation, and increasing its operating lifetime.