Research On The Key Technology Of 10KW Photovoltaic Grid Connected Power Generation

In recent years,because of the lack of energy and environmental pollution,the development of the new energy industry has risen to a strategic level in the world.As solar energy has the advantages of no pollution,unlimited storage and so on,the photovoltaic power generation industry stands out.In this paper,the key technologies,such as maximum power point tracking,grid connected current control strategy and islanding detection methods in 10KW PV grid connected inverter are studied in this paper.In order to ensure the efficiency of photovoltaic grid connected power generation system,a reasonable design of the maximum power point tracking method is needed.Firstly,the working principle of photovoltaic cell is expounded,and several traditional maximum power point tracking methods are introduced.Then research on output characteristics,when the photovoltaic array in partial shade.Finally,the optimal power search method is combined with the variable step size perturbation observation method to form an optimal power start golden partition method.The simulation results show that the method can quickly and accurately track the maximum power point in the global photovoltaic array in partial shade.The performance of the grid connected filter and the grid connected control strategy determine the quality of the grid current.First,the mathematical model of LCL filter is set up and its parameters are calculated.Then,Analysis of causes and harm of direct current component in grid connected current.Several methods of DC component suppression are compared and analyzed.The average current method and virtual capacitance method is combined and form a method of DC component suppression which suitable for three-phase non isolated grid connected inverter.Finally,the DC component suppression method is added to the classic double closed loop control strategy,and the fuzzy PIR controller is applied to adjust the grid current and the feedback value of DC component.The simulation shows that the grid connected current control strategy can improve the quality of the grid current and effectively suppress the DC component.In order to ensure the safety of grid connected equipment and network maintenance personnel,the grid connected inverter is required to have efficient islanding detection.First,the mechanism of islanding effect is analyzed,and the principle of passive and active detection is introduced.Then,we improve the initial disturbance,positive feedback coefficient and positive feedback quantity of active frequency shift with positive feedback,and propose a bidirectional fast active frequency frequency shift method.Finally,through the simulation analysis,the improved method has a smaller detection blind area,and the detection speed has been greatly improved.Finally,according to the system’s technical indicators and the general control block diagram,the components parameters,hardware circuit and software flow chart of grid connected inverter are designed.The experiment platform is set up,the hardware and software are debugged,and the content of the research is verified by experiment.