Comparison between desaturation sensing and Rogowski coil current sensing for shortcircuit protection of 1.2 kV, 300 A SiC MOSFET module

Silicon Carbide (SiC) MOSFET devices have small internal inductance and small on state resistance, resulting in a huge di/dt which will cause the current to rise to a high level very fast during shortcircuit (SC), causing possible destruction of module due to excessive dissipated energy or high overshoot during the turn-off. Therefore, fast and reliable protection circuit is important to detect the SC as fast as possible to minimize the power dissipation in the components during the fault, thus preventing the device from overheating and destructing. Furthermore, soft turn-off is required to avoid high voltage spike during the turn-off of the fault current. This paper compares and evaluates the SC performance of two different protection methods on CREE 1.2 kV, 300 A SiC MOSFET module. The first protection method utilizes desaturation technique (DeSat), while the second method utilizes a Rogowski coil to sense the current through the device. Experimental results are analyzed to determine which protection method behaves better under different operating conditions.