Research On The Virtual Control Strategy For Parallel Inverters In Microgrid

As the society to the traditional fossil energy depletion,new energy function is very important to society.And new energy is not controllable,and randomness,so people put forward the concept of micro grid,easy control of the distributed power generation system.Now contains a variety of distributed power of micro grid received extensive attention of people,their internal distributed power is to use the new energy power generation technology,less pollution to the environment,and therefore are popular with people.Distributed power supply and power grid are connected through the inverter,assurance and power grid stability,between common to provide electricity.And its stability between grid and need to take appropriate control strategy,therefore,the study of parallel inverter control strategy is very far-reaching significance.The background and significance of topic is described in this paper,domestic and foreign research status of micro power grid is analyzed,and the research status of virtual impedance droop control.Through the analysis of traditional droop control,in view of its shortcoming,virtual impedance droop control method is proposed,and the existing virtual impedance method is used to output current derivative,so that the system is sensitive to the output current;Existing methods are all at the same time according to the analysis of the linear load,rare with the analysis of the nonlinear load,and the influence caused by nonlinear load and linear load is different.To solve above problems,this paper put forward a kind of dual second-order generalized integrator(DSOGI)virtual impedance control,the control strategy to avoid the virtual impedance the derivation process of output current in the ring,and in with nonlinear load is still can be a very good control of micro grid power quality,can realize the power split of system.In order to verify the effectiveness of the control theory,built in the Matlab/Simulink simulation model of the above mentioned control strategy compared with conventional droop control strategy of the virtual impedance results,the result shows the effectiveness of the improved method in this paper.