Improvement of Power Quality of Distribution Network by Photovoltaic Grid Connected Converter Based on Virtual Synchronous Control

The continuous increase of the proportion of flexible source load capacity in the new distribution network is conducive to improving the flexibility and controllability of the distribution network. Taking the PV grid-connected converter based on virtual synchronous control as the object, the path to improve the power quality of the distribution network is deeply studied. Firstly, considering the dynamic performance of phase-locked loop, the sequence impedance model of photovoltaic grid-connected converter in the maximum power point track(MPPT) mode is established, and the generation mechanism of power quality problems in distribution network with photovoltaic access is revealed. Secondly, the impedance model of PV grid-connected converter based on virtual synchronous control strategy is established and it is clear that this control strategy can reduce the equivalent impedance of the distribution network in the substation area, enhance the voltage support ability of the PV converter and improve the operation environment of the DC interconnection device, and prove its role in improving the power quality of the distribution network from the aspects of harmonic content and voltage fluctuation. It provides a new idea for active optimization and collaborative control technology of power quality in AC/DC hybrid distribution system. Finally, a simulation model is built in Matlab/Simulink to verify the effectiveness of the proposed method.