Investigations on Creepage Distances in Power Electronic Systems for Electrified Aircraft

Power electronics design offers many options to achieve the high required power density to replace conventional aircraft components. Two promising approaches are to increase the power supply voltage and use wide-bandgap semiconductors. However, there are many concerns about the high-voltage approach, particularly regarding reliability and fault tolerance. Improving the power density with high voltages requires wide-bandgap semiconductors, which further stresses the insulation. Furthermore, the environmental stressors are partly unknown because of the need for a design basis. Existing industrial standards and other investigations address this issue only partly. This publication uses a mission profile and a design of experiment-based reliability assessment approach for creepage distances on printed circuit boards to overcome the concerns against the promising high voltage approach in aviation applications from the perspective of power electronics. The investigation delivers experimentally and mathematically described wet and dry surface flashover results. Furthermore, the influence of degradation of creepage distances caused by wide-bandgap semiconductors is experimentally investigated. The publication also gives design recommendations for gaining reliability and fault tolerance of creepage distances on printed circuit boards for operating power-dense power electronics in integrated electrified propulsion systems.