Research On Control Strategy Of Microgrid Base On Photovoltaic Generation Power Mode

There is an increasingly prominent contradictions between environmental and energy issues,and it is necessary to find a kind of clean energy to replace the primary energy.Undoubtedly the Photovoltaic Power Generation is one of the best alternatives.Photovoltaic Distributed Power Generation is used in this articles,but in the development of Photovoltaic Power Generation,distributed power generation access made great impact to the distribution network and restricted its development,in order to solve this problem and the Micro-Grid came into being.The Photovoltaic Grid is connected to the distribution network through the power electronic interface,Which increased flexibility in distributed generation.Compared to the traditional generate system,it increase the difficulty between system power balance and frequency stability control.In this thesis,the research object is Micro-Grid which construted by Photovoltaic Power Generation,Master-slave control and point-to-point control.etc strageties of Micro-Grid running control and three kinds of distributed power convert methods PQ,V/f,Droop has researched,and simulation process gives photovoltaic cell model structure and three control methods in the key aspects of the parameter design.The simulation results show that the Micro-Grid model established can be used to study the grid and Micro-Grid control methods.(1)According to the principle of photovoltaic cells,the simulation model of photovoltaic cell is built by mathematical model.Using disturbance observation method change the Boost circuit duty cycle to achieve the maximum tracking of power point.The simulation results showed that the model has a strong adaptability to the external environment.The model of PQ control strategy of PV three-phase operation is realized,and the simulation results show the reliability and applicability of the model.(2)Aiming at the problem of the control strategy of the distributed power interface inverter,the simulation model of the master-slave control strategy of the micro-network is established.The principle of V/f and PQ control strategy is explained,and the simulation model is established in dq rotating coordinate system,The parameters of voltage and current double loop control in V/f control strategy are designed,and then the current loop control parameters in PQ control strategy are designed.In order to verify the validity of the V/f control model and the PQ control model,the control simulation model of the operation mode switching between the island operation and the grid operation is designed.The simulation results show that the V/f and PQ control strategies are in the master-slave control can have a good performance in islanding operation.(3)The principle of peer-to-peer control is used in islanding operation of Micro-Grid,and distributed power uses Droop,the principle of point-to-point and the principle of droop control are described first,and the parameters of power control and voltage and current double-loop control in the droop controller model are discussed,simulation model is constructed too.In order to meet the requirements of droop control,this paper uses the control parameters to design the impedance of the output impedance,and in order to meet the droop control strategy under the distributed power DC stable output and dynamic response faster Requirements,the use of DC power supply to replace the combination of photovoltaic cells and energy storage equipment.The simulation results show that the droop control can realize the power distribution of the public load and ensure the stability of the voltage and frequency of the microgrid.