PR controller for grid-connected inverter control using direct pole placement strategy

In this paper, the design of PR regulator which is applied on the grid-connected inverter with LCL-filter, is analyzed in details. By modeling the system under stationary frame, the open and close-loop transfer function is given, which is used in analyzing the impact of each parameter on root locus. Using the root locus theory, the proper parameters are selected so that the resonance of LCL-filter is attenuated, the current ripple is suppressed and the sinusoidal input is well tracked, which means the output grid current is of high quality. A 10kW prototype is built and the result of the experiments verified the effectiveness of the proposed PR regulator design.