Cast aluminum inverter enclosure: passive thermal design for reliability

Heliotronics, Inc., under contract with the New York State Energy Research and Development Authority (NYSERDA), did extensive development work on a cast aluminum inverter enclosure. This paper explores the advantages of casting for fully passive cooling in creating ultra high reliability inverters. We show thermal imaging, and simulation results that enabled us to take advantage of the unique properties of aluminum castings for fully passive and highly effective thermal performance. In particular use of the following advantages were explored: three-dimensional control over geometry, optimization of fin spacing, potting magnetics to effectively move heat out of the interior air space, utilization of entire enclosure surface area for cooling, strategic manipulation of thickness and shape to move hotspot heat away from desired cool zones, modifying thickness to optimize heat spreading and utilization of surface area, design of heat barriers to protect sensitive components, design to take advantage of interior convective flow for cool areas.