Research On Transient Characteristics And Low Voltage Ride Through Technology Of The Grid-connected Three Phase Photovoltaic System

With the rapid development of economic life and the rapid growth in power load, resource constraints in the global environment, new energy has become the development direction of the world. As a clean energy technology in recent years, solar power is developmenting rapidly. There are more and more photovoltaic system.Because of Government’s support for solar and other new energy industry, more and more three-phase photovoltaic system connected to the grid instead of there self-use.Since there are some differences of the mainstream principles between photovoltaic power and coal-fired power,the normal operation of the grid is affected.Based on the building photovoltaic grid system simulation model, focused on the low voltage ride through (LVRT) technology transient characteristics and photovoltaic systems through technology.And through the improvement of existing control methods to achieve a low voltage ride.For three-phase photovoltaic grid system, this paper is analyzed by establishing a battery, circuit, track simulator and an inverter model,built two different photovoltaic grid system simulation models,inmproved incremental conductance maximum power point tracking control,to achieve a unity power factor griding.This paper studies through modeling and Simulation of transient characteristics of three-phase photovoltaic grid connected system are studied..Through the single-stage and two-stage model simulation of PV systems building, studied the trends of each physical in photovoltaic systems when the outside light intensity mutation,grid Voltage sag and swell.Low voltage ride through of three-phase PV systems is achieved by improving the existing control system on the basis of comparaing analysis of the inverter control methods. This is verified the simulation results in MATLAB/SIMUINK.From the result of the verification run,When the grid voltage drop occurs,these is a positive effect by useing this method for inhibiting grid current increases and rapid recovery after the removal of the grid fault.At last, I Summaried the research work, prospected future research directions.