An Improved Distributed Control Strategy for Parallel Inverters

Parallel operation of inverters improves the reliability, maintainability, expandability, and standardization. Many control methods have been proposed. The master-slave method can not realize the redundancy because the slave modules are dependent on the master module, the wireless control method using frequency and voltage droop technique presents too poor output characteristics. Distributed control strategy achieves hot swap and redundancy, the output characteristics is relatively poor due to the inductor current feedback loop. This paper introduces the load current feed-forward control to the distributed control strategy to improve the output characteristics. Meanwhile, the functions of output current limiting and current sharing are remained. The output characteristics and circulating current with and without the load current feed-forward control are compared in this paper. The prototype of parallel inverters is built to verify the effectiveness of the improved method.