Simulation And Research Of Grid Connected Photovoltaic Generation And Microgrid Operation Control

As the energy and environmental problems become increasingly prominent, the distributed power generation (DG) is undergoing a significant development all around the world. Undoubtedly, the photovoltaic generation (PV) is the most representative DG which has great prospect.However, a large number of accessing to the tradition power grid by DG brought a lot of negative effects and the development of DG is also restricted. Microgrid is the most effective way to make use of DG. As a frontier area of research, Microgrid is the hottest issue which focused by many countries.Considereing the complexity and limitation of establish the Microgrid experimental system, the dynamic simulation model of Microgrid was established in software generally.The simulation model was used for research of DG grid-connected control, Microgrid operation control and also the issue of Smart Grid.Therefore, establish the simulation model of DG which represented by PV and control strategies of Microgrid operation has important practical significance.The purpose of this thesis is to establish the simulation platform of Microgrid operation control, the solar cell model and three typical Microgrid control strategies which consist of PQ, V/f and Droop were established in Matlab separately. Based on the principle of control strategies the model structure and parameter design were given.Effectiveness and correctness of the model was tasted through the simulation example.The result of simulation show that the model can be used in research of DG grid-connected control and DG access to Microgrid operation control. The model has great universal and expansibility.Firstly, Based on the principle of solar cell, a common engineering model is established. Perturbation and Observation method (P&O) is used to control the boost converter to realize the PV Maximum power point tracking (MPPT). The results of simulation show that the method has good adaptability according to external environmental changing and good dynamic performance.Secondly, the simulation model of PV grid-connected operation control strategy was studied. The SPWM current tracking model was used to track the single-phase PV grid-connected control and the grid voltage feed-forward compensation is considered. Simulation shows that the control model can achieve unity power factor.Three-phase PV grid-connected is the key point of this thesis. The PQ control strategy was discussed and control model was established in rotating dq coordinate system. Software phase locked loop (SPLL) and current control loop design was discussed in detail. Simulation proved that the active power and reactive power were decoupled by using PQ control model.Thirdly, the model of V/f control strategy and Droop control strategy were given. This two models used in DG operation control such as Micro-Gas Turbines,fuel cell and combination of PV and energy storage unit. The model of V/f control strategy and Droop control strategy has great significance to Microgrid and island operation specifically. The principles of this two control strategy were analyzed, the model structure designs were given, the models were established in Matlab.The selection and design of model parameters was studied.Lastly, three examples were given for tasted the effectiveness and correctness of the model. Through the Microgrid master-slave operation control example show that the V/f model could follow the changing of load in island operation.The Droop control model was used in Microgrid peer-to-peer operation control control example, the result proved that the modle can adjust the system frequency and voltage automatically, keeping the power balance in isolated operation.An example which PQ and Droop control strategy was comprehensively used was designed. By using this example, the operation variations of the Microgrid, the change of load and the changing of electrical power was imitated and analyzed. Results of simulation proved the effectiveness of the model, show that those modles provided a effective way of eatablishment of simulation platform of Microgrid operation control.