Parameter Robustness Analysis and optimization Design of CLLC High Frequency Isolation Circuit Applied to Power Electronic Transformer

Power electronic transformer is the key equipment to realize the flexible access of distributed energy and new load/energy storage in distribution network. In this paper, the robustness analysis and optimal design of circuit parameters are carried out for CLLC DC transformer used in high frequency isolation link of SST. CLLC DC transformer can use open loop control to simplify control complexity, realize nearly constant bidirectional voltage gain in a wide range, and use the leakage inductance of high-frequency transformer as resonant inductance to reduce the difficulty of circuit design. In this paper, a parameter design method for CLLC DC transformer is proposed. Using this method, the designed CLLC DC transformer has good voltage regulation ability and wide range soft switching characteristics even when the inductance and capacitance value have design deviation. The influence of parasitic parameters of high-frequency isolation transformer and device on the voltage gain of DC transformer under light load is analyzed, Finally, a typical DC transformer is designed and verified by simulation in PSIM software.