Impact of Bond Wire Degradation on Thermal Estimation and Temperature Coefficient of IGBT Modules in Power Cycling Test

Decoupling the temperature effect on the on-state voltage (V_ce) is essential when only the bond wire degradation of the insulated-gate bipolar transistor (IGBT) needs to be characterized in the power cycling test. This process entails the acquisition of thermal information and temperature coefficient, along with careful consideration of the effects of aging on them in turn. In this paper, the impact of bond wire degradation on them is examined, which corresponds to the analysis of the temperature dependence characteristics of V_ce under two typical currents, the thermal sensing current and power cycling current. Moreover, the error associated with the existing temperature decoupling strategy is quantified theoretically. Based on this, a new decoupling scheme is proposed. The effectiveness of the corresponding analysis is validated based on the elaborate experiment design, a combination of degradation simulation, I-V characterization test, and thermal calibration. Additionally, the experimental results reveal that another factor, namely the linearity between on-state voltage and temperature, also can introduce errors into the decoupling process.