Efficiency and cost comparison of Si IGBT and SiC JFET isolated DC/DC converters

Silicon carbide (SiC) and other wide band gap devices are in these years undergoing a rapid development. The need for higher efficiency and smaller dimensions are forcing engineers to take these new devices in to considerations when choosing semiconductors for their converters. In this article a Si based converter and a SiC based converter is compared. Both converters are isolated DC/DC converters and were designed for 5 kW nominal outputs. Test setups for both converters were built and tested. The hardware differences between the two converters are described and performance is compared. An efficiency of above 97 % for the SiC JFET and over 90 % for the SI IGBT converter was measured. Cost differences between the two converters have been analyzed, showing that 772 days of operation are needed for the SiC converter costs to break even with the Si IGBT converter costs.