The Feasibility and Performance of Thin-Film Thermocouples in Measuring Insulated Gate Bipolar Transistor Temperatures in New Energy Electric Drives

In the new energy electric drive system, the thermal stability of IGBT, a core power device, significantly impacts the system's overall performance. Accurate IGBT temperature measurement is crucial, but traditional methods face limitations in IGBT's compact working space. Thin-film thermocouples, with their thin and light features, offer a new solution. In this study, Ni 90% Cr 10% and Ni 97% Si 3% thin-film thermocouples were prepared on polyimide substrates via magnetron sputtering. After calibration, the Seebeck coefficient of the thin-film thermocouple temperature sensors reached 40.23 μV/°C, and the repeatability error stabilized at about 0.3% as the temperature rose, showing good stability. Researchers studied factors affecting IGBT temperature. Thin-film thermocouples can accurately monitor IGBT module surface temperature under different conditions. Compared to K-type wire thermocouples, they measure slightly higher temperatures. As the control signal's switching frequency increases, IGBT temperature first rises then falls; as the duty cycle increases, the temperature keeps rising. This is consistent with RAC's junction temperature prediction theory, validating the feasibility of thin-film thermocouples for IGBT chip temperature measurement. Thin-film thermocouples have great application potential in power device temperature measurement and may be a key research direction, supporting the optimization and upgrading of new energy electric drive systems.