Research On Control Method Of Photovoltaic Grid-connected Inverter Based On Voltage Quality Of Low Voltage Distribution Network

As the supply of traditional energy going to becoming steadily tighter and the problems of environmental pollution going to be more serious,to develop and use new green energy has become a contemporary trend.Solar energy with its unique advantages is considered as an ideal green energy,and its photovoltaic grid connected technology is developing rapidly.As the core component of the photovoltaic(PV)power generation system,the distributed grid-connected inverter is very important,which determines photovoltaic capacity and permeability in the distribution system.The photovoltaic grid-connected inverter will be researched on its control method in this paper.First of all,various types of photovoltaic grid connected inverter topology are studied in this paper.According to the characteristics of distributed grid connected system,the basic topology type and filter of grid connected photovoltaic inverter are determined.Then,in order to reduce the pollution of the public network photovoltaic power distributed to grid,and improve the voltage quality of distribution network,the photovoltaic mechanism of voltage quality problems caused by the photovoltaic power accessed to the distribution network will be analysised,according to the characteristics of R/X distribution network smaller than the transmission line,preliminary put forward the idea of active power output limit of photovoltaic into the distribution network,and the rationality and feasibility of the idea are analysised in the research.Finally,The traditional measures to improve the voltage quality of distribution network and the limitations are discussed.It is a hot research topic to solve the problem of voltage quality caused by PV incorporation into distribution network by controlling inverter.Through the comparative analysis of control method of photovoltaic grid connected inverter put forward by experts at home and abroad,considering the distribution network voltage quality,network loss and line capacity,inverter capacity,power factor and other constraints,optimize the control strategies proposed by predecessors.Finally,put forward the improved control method of photovoltaic grid connected inverter.And in the simulation system,the model of system is build,then their simulation verifications are made,veryfing the applicability of the method.