Research On Voltage Regulation Of Photovoltaic System Based On Modulation Operation Of Inverter With Multi Reactive Power Source

With the development of photovoltaic grid-connected technology and the increase of grid-connected capacity,the influence of photovoltaic system on power grid is becoming more and more obvious.The fluctuation of photovoltaic output will cause the voltage to be deviated even more limited.The photovoltaic system must have a certain reactive voltage regulation capability.In this paper,the reactive power output capability of grid-connected inverter and reactive power compensation device is integrated,and the control strategy of multi-resource source coordinated voltage regulation is proposed.The main tasks as follows:1.The reactive power control mode of the grid-connected inverter is analyzed.The inverter reactive power compensation capability is discussed from the aspects of inverter operation mode,reactive power output state,reactive voltage support principle and reactive power limit,and the reactive power capacity is explained.Within the constraint range,the inverter's reactive power adjustment capability can be used to stabilize the grid voltage.2.The design of the inverter control system is studied.The corresponding control model is established in the dq coordinate system.The design of the filter circuit,power feedforward,current inner loop and voltage outer loop is studied in detail to realize the decoupling control and fast of active and reactive power.Tracking improves the reactive response capability and lays the foundation for reactive voltage control of photovoltaic systems.3.This paper discusses the reactive voltage control strategy of photovoltaic system,analyzes several existing reactive voltage control strategies,and proposes a cos?(P)-Q(U)reactive voltage control strategy to realize real-time response of photovoltaic power supply and the change of power and voltage,dynamically distribute reactive power to regulate voltage stability.4.The cos?(P)-Q(U)control strategy is combined with multi-resources to carry out voltage regulation research.The topological structure and grid-connected voltage characteristics of photovoltaic power plants are studied,and the active fluctuations and line parameters are applied to the voltage regulation effect and line loss.influences.The equivalent model of photovoltaic power station is built.From the perspective of the cooperation between grid-connected inverter and reactive power compensation device,the control strategy of multi-resource source coordination output is proposed.The simulation results shows that in this strategy,the photovoltaic power station can quickly track the changes of illumination conditions,and effectively stabilize the grid point voltage and reduce the line loss.