Control strategy of low voltage ride through capability of PV system based on SVG

Abstract

With the deterioration of environmental problems and the outbreak of the energy crisis, human beings are increasingly exploring new energy. As a distributed power generation, photovoltaic power generation is necessary to have the ability to ensure that it does not run off the grid in case of voltage dips. This paper proposes a control strategy of static var generator based on virtual synchronous machine. Compared with traditional vector control, this control strategy has faster compensation speed; Aiming at the problem of three-phase imbalance, the virtual synchronous machine control strategy can control the voltage of each phase separately; In this paper, the star connected direct mounted static var - generator is used to reduce the number of insulated gate bipolar transistors and reduce the cost; The control strategy effectively solves the problem of phase to phase balance of capacitor voltage at DC side. Finally, a grid-connected inverter model based on virtual synchronous machine is built through MATLAB / Simulink to quickly and effectively compensate for the voltage dips in the wind power generation system, which proves the feasibility of the control strategy.