Aging Diagnosis of Bond Wire Using On-State Drain-Source Voltage Separation for SiC MOSFET

Bond wire aging is a universal failure form of silicon carbide metal-oxide-semiconductor field-effect transistor (SiC MOSFET) module. Real-time condition monitoring of bond wire is an important guarantee for the stable operation of power electronics system. In this article, a method of monitoring the aging state of bond wire in SiC MOSFET module using on-state drain-source voltage (OSDSV) separation technique is proposed. Firstly, the temperature dependence of the conduction circuit resistance from drain terminal to source terminal in SiC MOSFET module is analyzed to obtain the temperature characteristics of the OSDSV. Secondly, the resistance of the package structure in SiC MOSFET module is extracted, and the OSDSV is divided into two parts: the package structure voltage and the chip OSDSV, and the analytical model for estimating the junction temperature of SiC MOSFET module in the healthy state is acquired. Finally, the package structure voltage is employed to monitor the aging degree of bond wire in SiC MOSFET module, and the flow chart of aging diagnosis of bond wire is established. The proposed method can accurately identify the failure state of bond wire lift-off. Theoretical and experimental results prove that the method is feasible.