50kW Nano-Crystalline Core Based Three Port Transformer for Triple Active Bridge Converter

TLDR: In this article, a 50kW high frequency three port transformer made of nano-crystalline core for three port phase shifted DC-DC converter integrating renewable energy sources (RES) and energy storages (ES).

Abstract: This paper discusses a 50kW high frequency three port transformer made of Nano-Crystalline core, for three port phase shifted DC-DC converter integrating Renewable Energy Sources(RES) & Energy Storages(ES). Phase shifted DC-DC converters need an isolating transformer with series inductances or leakage inductances for power transfer among different ports. However, using leakage inductances for a tape wound or Nano-Crystalline transformer as energy transferring element, causes high leakage fluxes to induce significant eddy currents & related losses in transformer cores. At high switching frequency, this eddy current losses can go too high, reducing efficiency. In order to avoid the eddy current losses in cores, an external inductor based approach along with the concentric winding transformer is presented in this paper for Three Port Phase Shifted Triple Active Bridge(TAB) converter. The three port converter can use either a three inductor or two inductor approach, which is discussed in this paper. The TAB converter uses 1.2kV & 1.7kV SiC Mosfets as switching devices along with Nano-Crystalline core based transformer & ferrite based series inductors. In this paper, analysis & design for concentric winding transformer and experimental results are presented.