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.

I. Introduction

Power electronics device is extensively utilized in aerospace [1], new energy utilization [2], electric vehicle [3], [4] and other fields, and their reliability requirements are getting higher and higher. SiC MOSFET is a commonly used wide bandgap power electronics device, which has a wide range of applications. When the aging of the device causes unpredictable failure, it may consume high maintenance costs and even cause catastrophic accidents. Therefore, the condition monitoring and fault diagnosis of SiC MOSFET module [5] can identify the health state of the device and find the cause of the fault, effectively reduce the failure rate of power electronics device, and improve the reliability of power electronics device.