Control of T-type Three-level Bidirectional Hybrid Rectifier Circuit for Electric Vehicle High-power Charging System

The three-phase unbalance of the grid voltage causes the flictuation of DC output voltage in the electric vehicle high-power charging system, therefore, causing the grid side current distortion. In order to solve this problem, a control strategy based on T-type Neutral Point Clamped (T-NPC) bidirectional hybrid rectification circuit is proposed. In the two-phase synchronous rotating coordinate system, a double closed-loop control method is established. The current inner loop performs current decoupling, and the voltage outer loop extracts the positive and negative sequence components of the grid side voltage, and increases the negative sequence voltage feedforward control. The simulation results show that the system operates in the case of three-phase voltage imbalance, the current-side harmonic distortion rate is 2.02%, and the DC voltage fluctuation rate is about 0.17%.