An improved inverter-side current feedback control for grid-connected inverters with LCL filters

The grid-connected LCL-filtered inverter is widely used in distributed power generation systems based on renewable energies. Single inverter-side current feedback control only needs to sample one current to realize both current control and inverter protection. However, with single inverter-side current feedback control, the closed-loop system is under-damped or even unstable due to the digital control delay. In this paper, an active damping control based on only inverter-side current feedback is proposed. With the novel control, the resonance in the digitally-controlled LCL-filtered inverter is successfully solved while only inverter-side current is sampled. Comparisons of the proposed and typical single inverter-side current feedback control have verified the improvement of the proposed control. Thus, the proposed control has good application prospect in grid-connected LCL-filtered inverters.