Implementation and power-loss characteristics of 400-V, 10-kW, 20-kHz three-way isolated DC/DC converter as a power routing unit for constructing microgrid systems

We propose an autonomous DC microgrid system in which a three-way isolated DC/DC converter is used as a power routing unit for constructing DC 400 V microgrid systems. As the unit in the system operates with various power flow patterns, a highly efficient system cannot easily be designed unless the dependence of the unit's overall loss on the flow pattern is suppressed and efficiency variations in all operational states are small. We made a prototype three-way isolated DC/DC converter consisting of SiC-MOSFETs rated at 400 V, 20 kHz, and 10 kW and demonstrated power distribution operation. We present the dependence of overall loss in the three-way converter as revealed by results of experiments and analyze the factors involved in this dependence.