A Thermal Management Design Methodology for Advanced Power Electronics Utilizing Genetic Optimization and Additive Manufacturing Techniques

Power-electronic converters are critical elements in current and future electrification efforts in transportation technologies. Safety and regulatory requirements in electric vehicles (EVs) have placed stringent new demands on the performance and reliability of the associated power electronics. In order to meet these challenges, novel architectures and construction materials are being utilized for optimizing the electrical and thermal performance of the converter systems. Due to the inherently-coupled nature of these aspects, thermal management strategies have become an integral part of the overall power-electronic design process. This paper presents a thermal-management methodology that utilizes genetic algorithms (GA) to generate topologically-optimized geometries for liquid-cooled heat sinks. These GA-generated heat sinks utilize impingement-cooling principles and leverage the flexibility of stereolithography manufacturing techniques to reduce cost, volume and weight of on-board electrical systems in EVs. This optimization process is then demonstrated for a novel 7-kW integrated power module (IPM) design that employs bare-die silicon-carbide devices on a hybrid printed circuit board utilizing ceramic elements embedded in the FR-4 substrate. Experimentally-validated electro-thermal multi-physics simulations of a GA-optimized heat sink show a 10.6°C reduction in average junction temperature of the heat-generating devices, while maintaining reasonable pressure drops and a narrow temperature variation of 1.2°C between the individual devices, as compared to the initial seed design. The results demonstrate the effectiveness of the co-design approach and the GA-based optimization methodology.