IGBT Junction Temperature Estimation Using a Dynamic TSEP Independent of Wire Bonding Faults

Despite that many temperature-sensitive electrical parameters (TSEPs) have been discovered for the online estimation of the junction temperature of IGBT devices, their wide adoption in the field is yet to come. This is because they are most susceptible to both the aging status and operating points of IGBTs, which can result in inaccurate results if not attended. In this study, a novel dynamic TSEP, the gate voltage undershoot VGE(np) of the complementary IGBT switch, is proposed. It is based on the crosstalk effect and measured during the turn-off switching transition of the controlled IGBT switch for its temperature estimation. Its monotonic temperature dependence has been identified with implications for the changing load current and bus voltage, which are experimentally verified using a 1200 V/450 A IGBT module. The theoretical analysis and experimental results also show that VGE(np) is independent of bond wire failures while providing comparatively high relative sensitivity. The MMC power equivalent experimental results are given to verify the feasibility of the proposed method in commercial engineering applications. Finally, the multivariate linear regression method is used to improve the ability to estimate the IGBT's temperature by accounting for the operating point.