DC Grid Interface Converter based on Three-Phase Isolated Matrix Topology with Phase-Shift Modulation

This paper introduces a novel commutation sequence for a three-phase isolated bidirectional high frequency link converter (HFLC), that is based on phase-shift modulation. The topology is composed of a full-bridge converter (FBC) and a three-phase matrix converter (MC) connected with a high frequency transformer (HFT). Capacitive snubbers can be applied at the dc side to reduce turn-off losses. The commutation sequence uses a quasi-resonance (QR) state to recharge the snubber capacitors, allowing fast zero voltage switching (ZVS) transient even at low loads. All converter switches operate under favorable switching conditions. Furthermore, at any time instant, two of the switches operate at reduced frequency. The paper introduces commutation sequences for both inverter and rectifier modes of operation. No additional circuitry is required, and the control can be made quite simple. The modulations were verified using PSIM simulation model.