A resonance suppression strategy of LCL-type grid-connected inverter based on compound voltage feedforward

This paper proposes a dual-current closed-loop resonance suppression strategy based on compound feedforward to address the inherent resonance peaks and grid voltage distortions of LCL-type grid- connected inverters, which affect the grid-connected power quality. Firstly, a grid-configured PV grid-connected power generation system model is constructed based on Virtual Synchronous Generator (VSG) technology. Then, a dual closed-loop control architecture of grid current and capacitor current is proposed to suppress the inherent resonance spikes of LCL filter circuit. Secondly, the combined feedforward control of capacitor voltage and grid voltage is developed to mitigate the effect of grid voltage background harmonics on the grid-connected current. Finally, the performance analysis of the control strategy is performed by MATLAB platform. The simulation results indicate that the proposed method can effectively eliminate the harmonics generated by the LCL-type grid-connected inverter and ensure the stable operation of the inverter with high fundamental amplitude and low harmonic distortion rate of the grid-connected current when the grid voltage is distorted.