Research On Voltage Stability And Harmonic Suppression Of Island Photovoltaic Microgrid

At present,the construction and development of the island independent microgrid is receiving more and more attention.For the energy crisis and environmental problems,a large amount of renewable energy is used in the power grid.Among them,the solar energy is clean and inexhaustible,and it is the most important.One of renewable energy.On the other hand,solar energy output is intermittent and distributed,which will bring problems such as grid voltage fluctuation,harmonic pollution,new energy consumption,It also has a serious impact on the safe and stable operation of the grid..The proposed power spring(ES)provides a new way of thinking about the problems brought by the grid connection of new energy.As a demand response technology,it can allow and promote the large-scale penetration of intermittent renewable energy without the need.A large amount of energy storage acts as a buffer between supply and demand,achieves the effect of stabilizing the grid voltage,and reduces the economic cost of island power grid construction.Most of the existing power springs are voltage source inverter(VSI)structures,mainly using voltage control strategies.The voltage regulation effect can be achieved to some extent,but when there is a harmonic component of a larger component in the grid voltage,a larger harmonic content is also introduced in the load to be controlled.For this reason,this paper adopts a kind of Current source inverter(CSI)power springs improve performance.A strategy with direct current control and harmonic suppression function control is proposed.The harmonic suppression module mainly adopts single-phase dqO conversion and second-order generalized integrator harmonic current detection method.Based on the Matlab/Simulink simulation platform,the model of the photovoltaic microgrid was built.The simulation results show that compared with the existing control method,the voltage source inverter is changed to the current source inverter and replaced by direct current control.Voltage control can greatly reduce the total harmonic distortion of the load.In addition,DC control can explain the concept of ES more clearly.System performance can be further improved by the additional harmonic suppression module.