Real-Time Junction Temperature Monitoring Method for IGBT Power Modules of VSC Converters Based on Digital Twin Technology

The Insulated Gate Bipolar Transistor (IGBT), with its high current density and low saturation voltage, has become an essential component in Voltage Source Converter based High Voltage Direct Current (VSC-HVDC) systems, where its operational reliability is decisive. Junction temperature is a key parameter reflecting the operational state of the IGBTs and is closely related to the aging and failure degree of the device. Hence, online estimation and sensorless monitoring of junction temperature are important for ensuring the reliability of the transmission system. This paper examines the IGBT power module in the VSC and presents a real-time junction temperature monitoring and reliability assessment method based on digital twin technology. Firstly, an electro-thermal coupling model of the IGBT is established based on power loss principles and heat conduction theory. Secondly, a real-time junction temperature monitoring method based on data-driven digital twin technology is proposed. An IGBT digital twin, which represents the multidimensional mapping relationship between electrical parameters and temperature, is constructed based on the electro-thermal coupling model. Finally, the validity of the proposed method is justified under various operating conditions of the VSC-HVDC grid-connected system using PSCAD/EMTDC-MATLAB co-simulation technology. The research outcomes of this paper provide theoretical support for targeted maintenance and inspection of subsequent devices.