Gate Driver Design for 1.7kV SiC MOSFET Module with Rogowski Current Sensor for Short-circuit Protection
The SiC MOSFET, when used as a wide-bandgap device, has superior performance for its high breakdown electric field, low on-state resistance, fast switching speed and high working temperature. The high switching speed enables a high switching frequency, which improves the power density of high-power converters. The cost of the SiC MOSFET is also gradually decreasing due to its growing of usage in industry applications. Therefore, the SiC MOSFET is of great potential in medium-voltage (MV) high power applications as a substitute for Si IGBTs. A well-performing gate driver with sufficient protections is critical to ensure excellent performance of a SiC MOSFET module. The driver must be capable of features such as low propagation delay, high driving current, good dv/dt immunity, and effective protections that includes correct detection and fast responses.
This paper compares different configurations and proposes a best power architecture for dv/dt immunity, as shown in Fig. 1. On the basis of these findings, the driver IC is selected from a number of candidates. Next the external current booster, soft turn-off and active Miller clamp circuitry are designed for the selected driver IC. A conventional desaturation short circuit protection circuit is kept in the circuit design, but an aditional short-circuit protection circuit based on the Rogowski current sensor on the PCB board is added for effective protection. The test results obtained from the experimental setup (shown in Fig. 2) show that all the designed circuitry has good performance for device driving and protection.