Study on Centralized PCCVF Method for Multi-Band Resonance of New Distribution Network

In the presence of a weak grid, the resonance of the power grid could impact the stability of the LCL filter grid-connected inverter, their performance can become worse, because the resonant frequency is affected by changes in the grid impedance, resulting in an unstable region. Therefore, it is necessary to design the control system to deal with these problems. In this paper, a simple and robust method based on voltage feedforward at a point of common coupling (PCC) was adopted, which achieved the purpose of reducing the cost investment, The strategy was applied to only one of the grid-connected inverters. The results demonstrated that the system's stability was ensured, as the proposed scheme did not affect the phase margin of the system. In order to verify whether the harmonic radiation can be suppressed by the proposed strategy, a grid-connected inverter system operating in single-phase was simulated and tested.