Photovolatic Grid Power System Control Method Research

With the contradiction between energy supply and demand have becomeincreasingly prominent, the sun as the ideal alternative energy has broad prospects fordevelopment,and photovoltaic grid generation is the trend of the development of solarenergy utilization.But now the high price of photovoltaic cells, with low energyefficiency.In order to effectively use the solar energy,So it is necessary to study thecontrol stretary of PV grid-connected systems.The main content of this article are asfollows:First of all, According to the need of research subject, A two level topology gridinverter without transformer is selected as the research object,the former part ofinverter use the Boost circuit to achieve the maximum power point tracking, the Afterpart use H5full-bridge level inverter circuit to implementation output power grid,Transformer is not used in this strusture,so it is has the advantages of small size, lowcost, and the control scheme is easy to implement.Second, the photovoltaic cells and working principle of the output characteristicsis stuied, Simulation model is established based on the common parameters providedby the manufacturer, laid the foundation for subsequent simulation.Then, several commonly used photovoltaic maximum power point trackingmethod is stuied. and the maximum power point tracking of photovoltaic cells isproved theoretically can be achieved by change the duty cycle of the DC/DCconverter. Based on this, a fixed voltage speed to start with variable step Perturbationand Observeation method is presented in this paper. he feasibility and effectiveness ofthe scheme is verified with simulation.Finally, photovoltaic grid-control method is stuied, A kind of adaptive hysteresiscontrol method is brought in this paper, its effectiveness is proved in the simulationwith Matlab.