Grid-Connected Current-Delayed Cascade Feedback Control Strategy for LCL Inverters

The rapid development of distributed renewable energy power generation and grid-connected technology is of great significance in promoting low-carbon transition and coping with climate change. As a bridge for new energy input to the grid, LCL grid-connected inverter can improve the quality of grid-connected current very well. However, it is easy to trigger current resonance during grid connection to destabilize the system, resulting in significantly poorer waveform quality of the grid-connected current. In addition, the weak grid environment containing grid impedance also affects the robustness of the inverter and triggers harmonic resonance. In this paper, the grid-connected current delayed feedback active damping control based on LCL grid-connected inverters uses cascaded delayed feedback links to improve the amplitude margin and enhance the system's adaptability and robustness to the dynamic impedance of the weak grid.