Design Of Switching Current Sensor For Three-Phase Sic Inverter

This paper proposes an offset compensation method of the switching current sensor for the current control of the three-phase SiC inverter. Switching current sensors with Rogowski coils, which have analog signal processing circuits implemented with the operational amplifier (op amp), are integrated into the four-layer PCB gate drive board; in the end, the phase currents are reconstructed with the op amp subtractor. To eliminate the op amp offset voltage and bias current effect on the sensor output, an offset compensation S/W algorithm is proposed. A three-phase SiC inverter prototype was built and tested with the three-phase load to verify the feasibility of the method.