Design synthesis study on air cooling feasibility of power electronic components of an electric vehicle using full vehicle CFD simulations

Conventional Internal Combustion (IC) engine vehicles have electronic components that operate at lower voltages with minimal heat losses, requiring less/no cooling for its optimum performance. Electric vehicle (EV), on the other hand, would need electronic components that handle larger power needs, called power electronic components which are direct current to direct current (DC-DC) converter, traction control unit (TCU) and on board charger (OBC). Cooling requirements for such components have to be assessed properly during design phase to minimize loss of performance and life degradation due to temperature. Current work is a study on the feasibility of air cooling as an effective technique for above mentioned components that are packaged in the under-hood of a converted vehicle. Vehicle level under-hood underbody Computational Fluid Dynamics (CFD) simulations are carried out to quantify real life behavior of components to design changes. Design iterations on ducting and under-body components are done to improve cooling of these components. Improvements observed even though are large, power electronic components are not sufficiently cooled to operate at their optimum limits. Hence it is concluded that air cooling is not a feasible cooling solution. Further liquid cooling is opted for power electronic cooling.