An In-Situ Method for Health Condition Monitoring of SiC Power MOSFETs Under Repetitive Short-Circuit Stress

In the Silicon-Carbide (SiC) based power conversion system (PCS), SiC power MOSFET is one of the core devices in the system. Therefore, the health condition monitoring of SiC power MOSFETs is important. In this work, the variations of threshold voltage (V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</inf> ) and gate-source leakage current (I<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gss</inf> ) are converted into the changing rate of drain-source voltage (V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ds</inf> ), and the changing rate of V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ds</inf> is selected as the new aging-sensitive parameter. Then, a health condition monitoring method based on the principle of capacitive coupling is proposed. The method is completed by using a voltage sensor without any additional circuits, and the corresponding modeling is carried out for the SiC power MOSFETs. Besides, Short-Circuit (SC) stress is applied to degrade the devices, and the degradation behavior is investigated. Moreover, the health condition monitoring method has been simulated and experimentally verified in the Boost converter, the simulation and experimental results show that the changing rate of drain-source voltage of the devices in the Boost converter could be used to indicate the degree of degradation of SiC power MOSFETs. The work may be useful for degradation monitoring of the SiC power MOSFETs in PCS.