Advanced Thermal Management of Very High Power Electronics

The proposed program will develop an integrated thermal management system to cool IGBT modules at heat fluxes up to 1000 W/cm2 while keeping the junction temperature within 125¿C. An AlN (or CVD diamond or BeO) substrate works as a good electricalinsulator as well as a good heat spreader. Water spray cooling is used to remove heat from the exposed surface of the substrate. The feasibility and effectiveness of the developed concepts to reduce the internal and external thermal resistances of IGBTwill be demonstrated by measuring the junction temperature with Electrical Test Method (ETM) at different heat flux conditions. A complete thermal management system for a full Navy electronic power system will then be designed. The primary benefit ofthe proposed technique is to increase the effectiveness of heat removal from the IGBT chip to the ambient so as to improve the performance and reliability of the chip. The new substrate packaging for IGBT reduces the number of interfaces, risk of solderimperfections and thermal fatigue. Water spray cooling provides an effective method to remove the extremely high heat flux with a high heat transfer coefficient. It requires only a low flow rate compared to the conventional single phase techniques such asmicro-channel heat exchange and jet impingement. The spray cooling technique can be scaled up to cool large systems with large thermal loads. This effort will also be helpful to thermal management for other systems or devices with high heat flux such assolid-state and diode lasers.