Research on three-phase grid-connected inverter control system with voltage tracking and anti-disturbance performance

Given that the traditional three-phase LCL-type grid-connected inverter controller needs an accurate mathematical model to have good control performance, this paper introduces the Differential Flatness-based Control (FBC) strategy into the power outer-loop controller of grid-connected inverter, which does not need accurate mathematical model and has good tracking ability. In addition, the Linear Active Disturbance Rejection Controller (LADRC) is introduced on the basis of the FBC to improve the influence of inverter coupling and uncertain disturbance on the system, and the anti-disturbance capability of LADRC is also analyzed. The simulation results under different working conditions based on MATLAB/Simulink software show that the proposed FBC+LADRC control strategy not only has good voltage tracking ability, but also has good current output ability in the case of grid voltage amplitude disturbance.