Active Clamp Circuit for Online ON-State Voltage Measurement of High Voltage SiC MOSFETs Power Module

This paper deals with online measurement of degradation sensitive electrical parameters of silicon carbide (SiC) power MOSFET. The purpose is to target a health monitoring approach for power module allowing more reliable power electronic converter. The on-state resistance RDSON is one of the key aging indicator of SiC MOSFETs as it can provide information on both chip and packaging degradation. This on-state resistance can be deduced using both the on-state current and voltage of the power semiconductor. This paper focuses on an on-state voltage measurement circuit for medium-to-high voltage SiC power modules for aerospace applications up to 3.3 kV. In the literature, power module bondwires resistance can not be measured due to high switching voltage oscillations. An on-state voltage measurement circuit that can withstand such oscillations is proposed. The dedicated circuit is successfully tested on a double pulse bench for various module base plate temperatures and compared to data obtained with a static curve tracer Keysight B1505. Finally, the proposed circuit scope of application is discussed in a PWM inverter context.