Thermal Simulation and Experimental Validation of EV Off-Board Charger: A Correlation Study

In an electric vehicle, the Off-Board Charger (OFBC) is an essential component that converts AC power from the grid into DC power to charge the battery. During this process, the vehicle is getting charged, and a lot of heat is generated during the process. This present study is mainly focused on the modeling of OFBC in view of CFD simulations and validating the simulation results with experimental testing in the laboratory. For this purpose, we have carried out the CFD simulations and experimental tests. To perform the CFD simulation, we have used Ansys Icepak as a solver, which is a dedicated tool for electronics cooling. The simulation process includes the modeling of heat sources with appropriate material properties assigned to them, environmental conditions like ambient test temperature, and forced convection introduced because of the axial fan present in the assembly. With the help of the CFD model, we were able to analyze the thermal performance under given operating conditions and given charging scenarios, allowing for the identification of hotspots. Furthermore, we observed that results obtained during the simulation were well correlated with experimental results. In addition to the base simulation, we have also simulated to evaluate the impact of other key influencing factors such as changes in the component layout, heat sink efficiency, and airflow patterns for better performance of the OFBC. Based on simulation results, we have recommended the design modifications and improved cooling mechanisms, which resulted in improved thermal performance, which also benefited the reliability of the OFBC.