Grid connected inverter control by two-degree-of-freedom robust H∞ repetitive

This paper presents a robust control strategy for voltage controller of grid-connected inverter. The combining of feedforward control and H_∞ repetitive control is introduced to improve tracking performance and reduce periodic disturbance. The feedforward part of 2DOF controller extends gain and tracking bandwidth of the feedback controller when comparing to 1DOF controller. The proposed controller achieves the robust regulate voltage and tracking performance in dynamic responses. The controller is tested by simulation in MATLAB/SIMULINK. The results show the proposed controller obtains better performance under different scenarios (grid-connected mode and grid frequency variation).