Circulating Current Mitigation of Paralleled AC/DC Rectifiers with Zero-Sequence Compensation and Carrier Synchronization

With the rapid development of power electronics, the demand for high-power rectifiers is increasing. The use of parallel-connected modular rectifiers helps improve system performance and reduce costs. It not only increases the power capacity but also enhances the resilience of the power supply system. However, when there are mismatched parameters between rectifiers, circulating currents would be generated due to different PWM control strategies or switching timing among the rectifiers. This leads to current distortion and a decrease in system performance. In this paper, the 0-axis ab feedback control method with carrier synchronization technique is proposed to mitigate circulating currents. Some simulation and experimental results are offered to verify the validity of the proposed circulating current control method.