A Three-Phase Isolated Bidirectional AC/DC Converter and its Modified SVPWM Algorithm

This paper proposes a three-phase isolated bidirectional ac/dc converter. The converter achieves buck-boost ac/dc bidirectional conversion, sinusoidal ac current, and high-frequency electrical isolation with single-stage structure. The traditional SVPWM algorithm should be modified to keep the voltage-second balance of the transformer. The circuit derivation, operation principles, and SVPWM algorithm are presented specifically. The solution for shoot-through problem is proposed, which does not need extra dead time. To verify the theoretical analysis, the proposed converter was simulated by MATLAB/SIMULINK and a 3 kW prototype was built in the lab. The simulation and experimental results show the high power factor and the low harmonic distortion characteristics of the circuit.