Abstract: The realization of active damping for the feedback state variables of the LCL filter requires high precision sensors to have better flexibility and robustness. Therefore, this paper proposes an active damping method of grid-connected current fed back by negative second-order generalized integral quadrature signal generator. While suppressing the resonance peak, it also reduces the influence of grid-side voltage back‍ground harmonics on grid-connected current, and reduces the number of sensors to increase system re‍liability. The parameters of negative second-order generalized integral orthogonal signal generator are de‍signed around the stability margin of the system by pole assignment method. Then, the robustness of the system is discussed when the LCL parameters and grid impedance change under the active damping control system . The simulation results show that the proposed strategy has better effect in all aspects.

Key words: negative second-order generalized integral quadrature signal generator, LCL filter, active damping, parameter design