A Real-Time Junction Temperature Evaluation Method Based on the Reduction Thermal Model for IGBT Module of Traction Converter

The insulated-gate bipolar transistor (IGBT) module is a critical component of the traction converter in rail transit vehicles, and its reliability is essential for the safe operation of these vehicles. Junction temperature is a key parameter affecting the performance and reliability of IGBTs. Existing onboard traction converters lack effective methods for real-time monitoring of the IGBT module’s junction temperature. To address this issue, this article proposes a reduction thermal modeling approach based on Galerkin projection for real-time assessment of the junction temperature in IGBT modules. The high-order heat conduction equations can be projected into a subspace by only inputting the converter’s IGBT module’s convection coefficient and power loss and utilizing an eigenvalue decomposition method based on singular value decomposition (SVD) to extract basis vectors. This allows for generating a thermal field temperature map of the IGBT chip without additional external circuits or sensors, facilitating real-time and accurate evaluation of the IGBT module’s junction temperature. Finally, a power cycling experimental platform for the IGBT module was established, and comparative experiments under various operating conditions were conducted. The experimental results validate the real time and accuracy of the proposed method for assessing the junction temperature of IGBT modules.