Research On Control Method Of Photovoltaic Generation System Based On Switching Mode

The non renewable nature of fossil energy and its contradiction with environmental demand make people pay more and more attention to the development and utilization of new energy.Solar energy as a representative of clean energy has become the focus of new energy development and research.In this paper,photovoltaic power generation system is taken as the research object,and two aspects are studied from the following aspects: the efficient utilization of PV output and the application demand of PV grid connection.By introducing switch mode,we can improve the efficiency of photovoltaic power generation system MPPT and improve the performance of dual mode inverter on the one hand.First,in order to maximize the use of light energy and improve the input power of the system,based on the principle of the maximum power point tracking and the realization of the circuit,the principle and the superiority of the existing maximum power point tracking(MPPT)algorithm are analyzed in view of the MPPT problem of the front stage photovoltaic cells.A model predictive control based on the model predictive control is proposed.The switched MPPT method(Model Predictive Control,MPC)is used to solve the contradiction between the accuracy and complexity of the existing algorithm.Through the construction of the simulation model of the photovoltaic power generation system,the proposed switched MPC method is compared with the traditional MPPT method.The simulation results show that the switched MPC method has better performance on the MPPT.Then,in order to ensure that the dual mode inverter can switch smoothly between the two modes of grid connected and off network,the optimal power quality transmission is realized.The requirements of the seamless switching of the dual mode inverter are analyzed.On the basis of the analysis of the structure parameters,control strategies and the causes of the sudden change of the electric pressure during the switching process,the two mode inverters are analyzed.A switching method which can minimize the voltage abrupt variable in the switching process by the current controlled off network is presented,and the handoff method is simulated under the quasi PR controller.In view of the problem that the voltage distortion can not be completely eliminated in the simulation process,on this basis,a nonlinear quasi PR based switching control method is proposed,and the nonlinear quasi PR controller is designed.The simulation results show that the switched control method based on nonlinear quasi PR has good control effect on the switching between two modes,which can ensure the smooth switching between the photovoltaic power generation system in the two modes of off network and grid connected.Finally,the simulation results verify the effectiveness of the proposed control method for the two levels of PV generation system.The MPC based switching mode MPPT method can achieve the effective tracking of the maximum power point of the system,The dual mode switching method based on the current control and off-gird with the nonlinear quasi PR controller can effectively suppress the voltage distortion during the switching process and achieve a smooth switching.