Resonant power electronic transformer for power grid

To provide an interface equipment between medium voltage ac grid and low voltage dc grid, an innovative resonant power electronic transformer (PET) structure is proposed and analyzed in this paper. Only one high frequency transformer is used in the proposed converter. To achieve high voltage with low voltage device, modular multilevel structure is introduced as converter valve. The proposed converter includes two decoupled stages. The isolated dc-dc stage can achieve energy transfer and voltage conversion between medium dc voltage and low dc voltage, providing an opportunity for future dc power distribution. Base on the proposed topology, phase shift control for dc-dc stage is introduced. A 100kW simulation model is built up in Simulink/MATLAB. The simulation results verify the feasibility of proposed structure and control method.