Research on Overcurrent Detection and Protection of High-Power SiC MOSFET Driver

In the application where the switching frequency is above 50kHz, the pulses that drive the high power silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (MOSFET) need special requirements to be considered for the output power. Due to the affected by the characteristics of SiC MOSFET chip, such as small area and high current density, the device heat serious. When the device or the bridge arm under the condition of overcurrent and short circuit, at the moment, the driver circuit must response as fast as possible. Compared with the conventional silicon (Si) insulated gate bipolar transistor (IGBT), SiC MOSFET requires shorter overcurrent detection and protection execution time. Due to the characteristics of the device, too fast switching speed leads to voltage oscillation, which can cause misjudge of the overcurrent detection circuit. Aim at the error judge in the V DS desaturation overcurrent detection method of SiC MOSFET, this paper proposed a new method that combine V DS desaturation overcurrent detection with pulse by pulse soft turn-off overcurrent detection and protection method. Firstly, the working principle are introduced, and then the feasibility and effectiveness of the proposed approach have been validated by simulation results in PSPICE. A Short Circuit Tester (SCT) based experimental test setup further verifies the proposed protection principle.