An Adaptive Temperature Observer for Electrothermal Analysis of IGBT Based on Temperature Characteristics

Most of the existing methods for electrothermal analysis of the aging insulated gate bipolar transistor (IGBT) modules have limitations on performing synchronous recognition and decoupling of two typical aging models, and failed to be low-invasive and real-time. To address this, two characteristic functions are developed in this article. The characteristic functions are derived from the temperature response under periodic power loss excitation and can be extracted in real-time and low-invasively from the negative temperature coefficient (NTC) thermistor sensor integrated into the IGBT module. Then, a temperature observer based on the 3-D state-space model of the IGBT module is designed, which is based on the feedback from the characteristic functions, to achieve the target of online electrothermal analysis for the IGBT module even with the significant deterioration of the IGBT module. Finally, the performance of the proposed method is thoroughly investigated by extensive experimental tests.