Harmonic Compensation Control Method of Grid Simulator Based on Generalized Second-Order Differential

The LC-type grid-connected inverter is susceptible to the effects of grid harmonics., and the grid simulator can be used to simulate the occurrence of the background harmonics of the grid to ensure that the harmonic components of the inverter when it is connected to the grid meet the corresponding requirements. Due to the complexity of the harmonic compensation control strategy of the grid simulator, the simulation accuracy for specific harmonics is not exact and the stability is poor. To solve this problem, a generalized second- order differentiator is constructed and used for harmonic compensation in the paper. The controller can realize the phase-frequency characteristics of lead compensation for a specific frequency range based on the differential action, and eliminate the inherent noise interference at high frequency for the differential. By connecting the harmonic compensation control loop based on the generalized second-order differentiator in parallel with the double closed-loop PI control, the amplitude-frequency characteristics of the compensator for a specific frequency range can be freely adjusted by optimizing the parameters of the generalized second-order differentiator, and the accurate simulation of fundamental waves as well as specific sub-harmonics can be realized. Finally, the effectiveness of the proposed strategy is verified by MATLAB/Simulink simulation.