Research On Power Quality Problems Of Distributed Inverter System Connected To Distribution Network

The global energy crisis and environmental problems have stimulated the demand for renewable energy applications.In order to better connect the renewable energy to the distribution network,the distributed inverter system technology has gained wide attention.However,a large number of grid connected inverters,controllable or uncontrolled rectifier load and other converter equipments make the distribution network generate complex power quality problems.This paper puts forward a distributed inverter system power quality control strategy.The inverter has the advantages of multiple functions to actively participate in the power quality management role.To solve the above problems,this paper firstly puts forward a structure of the distributed inverter system and the mathematical model of the distributed inverter system under the condition of balance and imbalance.The advantages and disadvantages of traditional control methods of distributed inverting system are introduced.And a control method of multiple distributed inverters based on adaptive virtual impedance is proposed.The simulation results show that the proposed method can suppress the circulation between multiple distributed inverters and improve the power sharing between multiple distributed grid connected inverters.So it can provide a basis for power quality control strategy.Secondly,this paper has studied the influence mechanism of the distributed inverter system on the power quality of distribution network power and the distributed inverter system connected to the distribution network of the beneficial and adverse effects caused by the quality of electric energy.Then through simulation this paper discusses the impact of power quality difference under the distributed inverter system of different output and the location.At the same time,this paper proposes a distributed inverter system connected to the distribution network under the power quality evaluation method for distributed inverter system power quality control strategy to provide reference.Finally,a power quality control strategy for distributed inverter system based on Virtual Synchronous Generator(VSG)technology is proposed in this paper.In the distribution network environment of large-scale distributed inverter system,the control strategy proposed in this paper has short adjustment time and good adaptive performance.Through the grid model with large-scale distributed inverter system,the simulation of different conditions show that the proposed control strategy can effectively inhibit the occurrence of harmonic,and realize the distributed grid connected control inverter system complete electrical energy quality comprehensive management.So it can verify the effectiveness and the reliability of the proposed method.