Integral 3-D thermal, electrical and mechanical design of an automotive DC/DC converter

Power electronics is finding increasingly more applications in high temperature environments where power density is also a driving factor. The engine compartment of a passenger vehicle is one such example. In this paper, an integral thermal, electrical, and mechanical design of a high power density dc/dc converter operating in the thermally harsh automotive environment is discussed. The interactions and interdependencies between the three design disciplines are considered. It is illustrated how these interactions can be manipulated and used to an advantage in meeting the harsh temperature and high power density requirements of the automotive converter. Packaging and circuit techniques are identified that can be used to this end. Two case studies of a 2-kW 14-V/42-V dc/dc converter for application in the automotive environment are considered. The first prototype achieved a power density of 170 W/in³ while the second prototype, operating with a higher environmental temperature achieved a power density of 120 W/in³. The experimental structures and practical results are presented. Technology issues concerning the three-dimensional construction of the prototypes that need research attention are also identified.