Time Efficient Integrated Electro-Thermal Model for Bidirectional Synchronous DC-DC Converter in Hybrid Electric Vehicles

This paper introduces a simple and fast method to calculate the junction temperature of power electronic devices in a 3-phase DC-DC converter by representing converter dynamics during a simulated drive cycle. Simulating a DC-DC converter as a switching model during a drive cycle, which can have durations of 1000 to 2000 seconds or more, requires long simulation times and/or high-processing units like cluster computers. Thus, this paper presents a state-space averaged model to describe the 3- phase interleaved converter dynamics in buck and boost modes. Converter dynamics of the averaged model are compared to those of the switching model at different operating conditions to validate the model. The full Simulink model includes a battery model, the buck-boost average model, a buck-boost temperature- dependent power loss model, and a thermal model. The power loss calculated by the proposed method is compared to that of the switching Simulink/PLECS model, and the error is found to be less than 4% over a variety of operating points.