500 kW Forced Air-Cooled Silicon Carbide (SiC) Three-Phase DC/AC Converter With a Power Density of 1.246 MW/m3 and Efficiency >98.5%

There is a continuous demand for high-power, high-efficiency, and high-density converters in various existing and emerging applications such as large motor drives, electric vehicles, more electric aircraft, and utility applications. Compared with conventional silicon (Si) insulated gate bipolar transistors (IGBTs), silicon carbide (SiC) MOSFETs can have lower switching loss and higher frequency operation capabilities, which enables higher efficiency and higher power density at the converter level. Meanwhile, to achieve a high power rating such as 500 kW, how to extend the current capabilities of existing SiC power modules, the choice of parallel schemes, the selection of passive components, cooling and mechanical structure design pose clear challenges in maximizing the system power density and efficiency. This article presents a comprehensive design of the world-first air-cooled 500 kW SiC dc/ac three-phase converter, which achieves a record-high power density of 1.246 MW/m
³
(1.246 kW/L) and an efficiency over 98.5%. The converter has been tested in the experiment to the full power rating, which provides benchmark results for high power SiC converters and their applications.