Simulation-Based Thermal Performance Study of a DC-DC Converter for EVs.

The low voltage systems are used for lighting applications, horns, infotainment system, sensors and control units as per lower operating rated voltage. Operating temperature is the main factor causing more than 50% of all power electronics failures. The DC-DC converter convert one level of DC voltage to another required level as per applications in the vehicle. To reduce weight, cost and having better vehicle packaging, manufacturers use DC-DC converter to meet the low voltage operating range usually 12V to 24V. In order to maintain the regulated output voltage above or below the range, step-up or step-down DC-DC converter are useful. Thermal design of a DC-DC Converter through thermal modelling and simulation approach is becoming more popular as it is less expensive compared to experimental approach. This study is performed to develop a thermally optimized DC-DC converter against higher power losses and to maintain the operating temperature of power generating components below its allowable limit. In this paper steady state thermal Simulation methodology of 130W DC-DC converter is carried out using Autodesk CFD Ultimate software. The thermal behavior of power electronic components on the PCB board of DC-DC converter is simulated and validated with physical test results. For this thermal simulation, power losses of Inductors, Capacitors and Mosfet are analytically calculated and considered. An ambient temperature of 600C is considered as a worst-case scenario in boundary conditions. Simulation results shows maximum temperature on magnetic component’s like Inductor and PCB. The maximum temperatures on PCB components are within allowable operating temperature range. This study shows good correlation in between thermal results and physical test results.