Multi-timescale Thermal Network Model of Power Devices Based on POD Algorithm

The heat transfer of power devices has the characteristics of multi-timescale. However, the traditional thermal network model is difficult to predict the temperature information of power devices at multi-timescale accurately. This paper proposes a multi-timescale thermal network model for power devices, with MOSFET as an example. First, we establish a finite element model for temperature calculation of power devices and then reduce the order of the finite element model based on the proper orthogonal decomposition (POD) algorithm. The reduced order model is converted into an equivalent circuit model by the node voltage method and integrated into the circuit simulation software. To demonstrate its general applicability, this paper also establishes thermal network models for both IGBT and SiC MOSFET devices, validates the multi-time scale thermal network models through ANSYS/Transient Thermal software and experiments. The temperature calculation results of the three power devices all indicate that the proposed multi-time scale thermal network model can calculate the temperature of power devices faster than ANSYS/Transient Thermal model, and has less than 5% error under test conditions. This paper is accompanied by a video demonstrating a comparison of the computational speed of the multi-timescale thermal network model with a finite element model. Finally, a case study of junction temperature calculation in a Buck converter is presented to illustrate the application method of the thermal network model.