| In an environment of global calls for the reduction of greenhouse gas emissions,my country has proposed a "dual carbon" goal.Our country has abundant solar energy resources.Photovoltaic power generation is characterized by high energy quality and pollution-free emissions.It has important value and significance for achieving the dual-carbon goal.Maximum Power point tracking control(MPPT)is one of the key points of photovoltaic power generation technology.With the booming development of photovoltaic power generation technology,MPPT technology is particularly important in improving photovoltaic efficiency and reducing power generation costs.This article mainly focuses on the realization of maximum power tracking and control methods for photovoltaic power generation.The main contents are as follows:1.This chapter mainly describes the basic principle of solar photovoltaic power cell,and the construction of solar photovoltaic power cell mathematical model,analysis of the output characteristics of photovoltaic cell,derive photovoltaic cell engineering mathematical model.The principle of maximum power point tracking is introduced,and the Boost transform circuit is selected to realize maximum power point tracking of photovoltaic power generation.The MPPT equivalent circuit mathematical model of photovoltaic system is established.Considering the characteristics of photovoltaic power generation system,such as nonlinear,time-varying and strong coupling,the linear active disturbance rejection control(LADRC)technology is introduced to realize the maximum power point tracking control,and thus the MPPT control method based on LADRC is designed.2.The engineering mathematical model of photovoltaic cell under uniform illumination is simulated.The output characteristics of the system model are analyzed.The relationship between output voltage,output current and output power of photovoltaic cell is deduced.The analysis summarizes the advantages of several common MPPT control methods shortcoming.Aiming at the problem of insufficient suppression of high-frequency noise signals by the linear extended state observer(LESO)in traditional LADRC,a lead-lag correction link is introduced to design an improved LESO,and applied to the system closed loop control.Photovoltaic cell array was simulated by Matlab/Simulink simulation platform,and the maximum power tracking curves of the two control modes were compared under different illumination intensity and illumination temperature.Comparative analysis shows that the linear active disturbance rejection control combined with the correction link(LADRC-C)makes the maximum power point tracking curve faster and more stable to,and when the lighting environment changes suddenly,the fluctuation amplitude is smaller and the immunity is stronger.3.The influence of the hot spot effect on the photovoltaic array and the corresponding protection measures are analyzed.The output characteristic expressions of the photovoltaic cell array in series,parallel and series-parallel modes under partial shading are deduced.The 3×1 and 3×3 photovoltaic arrays are set with different working conditions and local shading environments are analyzed,and the different working conditions are summarized.Single-peak and multi-peak conditions appear in the lower PU curve.Through analysis,the new error between the state variables corresponding to the LESO observer is used as the basis for adjusting the total disturbance.Thus,the LESO observation accuracy is improved and applied to photovoltaic power generation MPPT system.Three groups of typical local shading experiments were simulated on the Matlab/Simulink simulation platform,and the maximum power control effect of the system under the two control methods were compared.It proves the feasibility of the method and the improved MPPT control of LADRC can track the maximum power faster and more stably,and has stronger immunity to disturbances. |
PDF Full Text Request