A New Tuning Method of Multi-Resonant Current Controllers for Grid-Connected Voltage Source Converters

Resonant controllers (RSCs) are widely adopted for controlling power converters since they can track AC signals of both positive and negative sequences without steady-state error. However, the performance of RSCs has not been fully exploited due to the improper phase compensation angle and insufficient controller gain. In this paper, a novel controller parameters design method, which is based on the system error transfer function, is proposed to further explore the potential high performance of RSCs. Comparing with the conventional methods, more appropriate phase compensation angles can be obtained, which means that the stable region of the controller gain is extended. Since the proposed RSCs design method is able to maximize the controller gain, the controller sensitivity to system frequency variations can be decreased and the system response speed can be improved. The RSCs tuning procedure is given in detail, and comparative experiments between the proposed method and the conventional method are performed to validate the superiority of the proposed method.