Adaptive Impedance Reshaping Strategy Based on Three-phase LCL Grid-connected Converter

This article proposes an adaptive impedance reshaping strategy based on online impedance detection to provide adaptive suppression of broadband oscillation and increase the stability of grid-connected converter systems. The converter sequence impedance model and the network impedance obtained online are used to determine whether the system is at risk of oscillation. In order to enable the system to operate steadily under a variety of network conditions, the controller parameters are adaptively changed in response to the network impedance if there is a risk of oscillation. Lastly, simulation is used to confirm the efficacy of the suggested impedance reshaping strategy. The simulation findings demonstrate that the suggested approach can enhance system stability by modifying the system's phase margin in accordance with the grid impedance. Finally, an actual engineering example is used to implement the impedance reshaping technique. The findings demonstrate that the suggested approach is capable of modifying the converter control parameters in accordance with the grid impedance, thereby enhancing the system's phase margin and stability.