Research on LCL-filtered Grid-Connected Inverter Based on Fractional Order PI Controller

Abstract

With the high attention paid to new energy sources, grid-connected inverters with LCL filter have been widely used. In order to maintain the steady state operation of the system and reduce the resonance, the current double closed loop control decision with a PI controller is often adopted. However, the PI controller has only two adjustable parameters, Kp and Ki, and the adjustment accuracy is limited. This paper focuses on the simulation of the lightning interference and humid environment that inverters may face after being put into use in outdoor open space, such as solar power stations and so on. Since the fractional-order PI controller has three adjustable parameters, it can effectively improve the system performance and make the output more in line with the actual application requirements. Therefore, this paper selects the fractional-order PI controller and compares with the control performance of the traditional PI controller. Finally, the conclusion comes out that the system based on fractional order PI controller has stronger anti-interference ability and better robustness.