Virtual impedance‐based virtual synchronous generator control for grid‐connected inverter under the weak grid situations

In this study, an improved control method of the grid‐connected inverter is presented to enhance the harmonic suppression. The capacitor‐current‐feedback‐based active damping is applied to the LCL‐type grid‐connected inverter, which is controlled in the virtual synchronous generator mode. A virtual‐impedance design method based on modulation signal is proposed, which can not only enhance the stability of the inverter under the weak‐grid situations, but also improve the quality of voltage and current. The transfer function and the impedance model of the system are established to analyse the performance of the methodology. Finally, the experiment results are presented to verify the correctness and effectiveness of the control method.