Hard- and Soft-Switched
Technical Lecture Session
Soft-Switching DC-DC Converters
Dual Active Half Bridge (DAHB), Bidirectional Single Stage, PCB-based Busbar, Utility-scale application, Modular Converter
High efficiency, high density and low-cost power conversion systems are attracting attention in medium voltage high power applications. This paper presents a 1.5kVdc, 100kW bidirectional Dual Active Half Bridge (DAHB) using 1.7kV SiC MOSFET modules. The DAHB achieved an efficiency of 98.6% at full load of 100kW and a maximum of 99% at 45kW, operating in back-to-back DC/DC mode. The converter also achieved an efficiency of 97.8% operating in variable frequency DC/AC mode. Required dynamic Coss/Qoss data was extracted to achieve ZVS turn on over the full voltage range. An optimized PCB-based busbar design has significantly reduced the voltage overshoot across devices. Typical partial discharge inception voltage (PDIV) of the optimized PCB busbar is 1.7kVpeak with total charge < 10pC. The power density of the DAHB converter is 1.8MVA/m3 which is much higher than traditional two-stage industry products. The DAHB converter can easily be scaled up to 4.16kV/1MVA utility scale PV systems with input parallel and output series configuration.