High Efficiency Minichannel and Mini-Impingement Cooling Systems for Hybrid Electric Vehicle Electronics

Over the years, electronic equipment, especially semiconductor based devices, have found their applications in almost all fields of research. The demand for more power and performance from such electronic equipment has constantly been growing resulting in an increased amount of heat dissipation from these devices. While conventional cooling solutions have performed the task of heat removal, no straightforward extension has been possible for significantly high heat fluxes dissipated by smaller and more efficient electronic devices. Thermal management of high-density power control unit for hybrid electric vehicle is one such challenging application. Over the last few years, the performance of this power control unit has been improved and size has been reduced to attain higher efficiency and performance causing the heat dissipation as well as heat density to increase significantly. Efforts are constantly being made to reduce the PCU size even further and also to reduce the manufacturing costs. As a consequence, heat density will go up (∼200–250 W/cm2) and thus, a better high performance cooler/heat exchanger is required which can operate under the existing cooling system design (pressure drop limitation) and at the same time, maintain active devices temperature within optimum range (<120–125°C) for higher reliability. The focus of this paper is to discuss the development of various cooling options for high heat flux dissipating devices with severe size constraints. A parametric and optimization study on the selected designs was performed. Finally, the optimized cooler/heat exchanger was tested under actual running conditions. The methodology was to explore various high performance cooling options such as impinging jets, pin fins, and ribbed mini-channels and to arrive at new promising, conceptual designs. These new designs were then compared against similar conventional designs both numerically and experimentally. Additionally, conjugate heat transfer simulations were performed on partial packaging model to compare the various designs. Experiments were also performed to validate the simulation models and characterize the meshing parameters to perform cost and time effective calculations/simulations.