Thermal Analysis of a Directly Liquid Cooled Silicon Carbide Resonant Inverter for High Voltage Generation

One approach to reduce volume and weight of high voltage generators used in industrial or medical applications is the higher integration of the power inverter into the high voltage tank. Here, the insulating liquid is used for direct cooling. The designed full-bridge resonant converter based on silicon carbide semiconductors operates at frequencies above 500 kHz and at a maximum output power of 80 kW. The combination of high frequency operation resulting in smaller resonant elements and direct cooling of specially developed low inductance ceramic power modules using the insulating liquid in the high voltage tank is the key element for reducing weight and volume of the inverter. Therefore, this paper investigates the thermal behaviour of a directly liquid cooled silicon carbide resonant inverter for high voltage generation.