Design and Performance of the 850-V 100-kW 16-kHz Bidirectional Isolated DC–DC Converter Using SiC-MOSFET/SBD H-Bridge Modules

This article designs, builds, and tests the 850-V 100-kW 16-kHz bidirectional isolated dc-dc converter using the latest 1.2-kV 400-A SiC-MOSFET/SBD H-bridge modules, with focus on efficiency improvement. Here, SBD stands for Schottky barrier diode. It proposes intermittent operation with continuous-current mode (CCM), to reduce switching losses in partial loads. Experimental results verify that the conversion efficiency from the dc input to the dc output is as high as 99.3% at the rated power of 100 kW, and 99.2% at a partial load of 10 kW. These are measured and calculated, discarding auxiliary power losses of 82W in total, which are produced by the digital controller, gate-drive circuits, and cooling fans. Experimental transient waveforms show that no dc magnetic flux is included in the 850-V 100-kW 16-kHz transformer at intervals of switchover between the continuous operation and the CCM intermittent operation when power reversal from -100 to 100 kW is performed at an interval of 1 ms. Finally, this article presents an experimental and theoretical discussion on the voltage ripples appearing across the dc capacitor of each bridge.