Research On Microgrid Connection Of Island Distributed Generation Based On PQ Control Strategy

Development of the photovoltaic (PV) power and wind power in the island is an important way to solve the stability and security of the electricity. However, due to so many access of various distributed generation, as for the Powergrid, it brought a number of unfavorable influences, which restrict its development. A kind of Microgrid technology we put forward is a better solution. We used to adopt two strategies to control the connection of Microgrid and Powergrid:PQ strategy and V/f strategy. But in this paper, PQ strategy is the main part of the research on the connection of pv power and wind power in Microgrid. The main research work completed includes:1. Researching the model of the photovoltaic cells and the wind generator. The control method of the Boost circuit duty ratio is used into the model of photovoltaic cells. And the dynamic characteristics of the model have been analyzed.2. Researching the control of grid connection system of photovoltaic power and the simulation model. In the research on the three-phase photovoltaic power generation, discussing the principle of the PQ control strategy, software design of phase locked loop, and current control loop design.3. Researching on the control of grid connection system of wind power. Discussing the principle of double fed wind generator, PQ control of the stator flux orientation, and the stability of grid connection system of the double fed wind generator. 4. Discussing the control principle and strategy of the Microgrid, and putting forward a kind of PQ control strategy based on grid connected inverter. The inverter is the interface between microsource and the powergrid whose function lies in outputting active power and reactive power. The inverter is always voltage source type, which adjust the active power and reactive power by controlling the amplitude and phase angle of output voltage. When connecting to the main grid, all microsources will keep constant of output power. The frequency and voltage will be supported by the powergrid. The effect of the strategy in power control is remarkable.5. According to the distributed generation laboratory in Guangdong Power Grid Company Electric Power Science Research Institute, discussing the laboratory system, and establishing experimental platform of distributed generation of the island Microgrid, which include conventional generator system, photovoltaic cells system and wind generator system. And researching on the Simulink of the dynamic characteristics.