Control Strategy of High-voltage Large-capacity DC Transformer Applied in the Intelligent DC Distribution Network

In this paper, input-series-output-parallel multiple modules DC transformer with high voltage and large capacity is used based on the CLLC resonant converter, which provides a variety of ports for the DC load and distributed power supply at low-voltage DC side. Compared with the traditional transformers, the proposed DC transformers is helpful for distributed power consume, and improves the quality of electric energy. In this paper, the relationship between the output power, the phase-shifting angle and output voltage in the single module is analyzed, a control strategy is proposed for the power balancing by using phase-shifting angle. In addition, a bidirectional power flow control scheme is presented, which can achieve high efficient and flexible access of distribution resources. In the end, the simulation are carried out based on PSCAD.