Research On Maximum Power Tracking Control Strategy Of DC Busbar Photovoltaic Power Generation System

In the severe form of energy crisis and environmental pollution,the development and utilization of renewable and clean energy has become a hot spot for research and application.Solar energy is widely used because of its wide distribution and non-pollution advantages.Photovoltaic(PV)power generation uses inexhaustible solar energy resources and converts light energy into electricity through solar cells.The nature of photovoltaic cells determines their output power.In order to improve the efficiency of energy utilization,the use of Maximum Power Point Tracking(MPPT)is the most effective method.It can not only form a DC busbar type independent PV power generation system to solve the problem of electricity consumption in remote areas,but also connect to the grid through the grid connection to form a DC busbar type grid-connected PV power generation system,providing an important grid mode for PV building integration.The control strategy of DC busbar PV system is directly related to the stability of the system and the efficiency of solar energy utilization,however,there are few studies on the MPPT control strategy for DC busbar PV system.Therefore,this paper conducts an in-depth study on its control strategy,and the main research contents are as follows.(1)Analyze the PV cell model and PV system structure,establish an integrated mathematical model of DC busbar PV power generation system based on the typical structure of PV system,build the PV cell model using MATLAB,and discover the law that the constraints satisfied by the MPPT control strategy to realize DC busbar PV power generation system are influenced by external environmental parameters.(2)Based on the integrated mathematical model of DC bus type PV power generation system and the linearization of PV cells,the mathematical relationship at MPP is derived.The mathematical relationship between the PV cell output current,control signal and weather parameters is found out and an MPPT control strategy is proposed under the condition that the DC bus voltage is kept constant.MATLAB is used to simulate and verify the proposed control strategy,and the simulation results are compared and analyzed with the perturbation observation method,and the feasibility and superiority of the MPPT control strategy proposed in this paper based on the constant DC bus voltage can be found.(3)According to the charging condition of maximum power output and the linearization of PV cell,the mathematical relationship between DC bus voltage,control signal and weather parameters is deduced,based on which an MPPT control strategy is proposed,and the proposed control strategy is simulated and verified by using MATLAB,and the feasibility of the MPPT control strategy proposed in this paper can be found by analyzing and comparing with the disturbance observation method.(4)Analyze and calculate and select the appropriate component parameters and types,build a DC bus type PV system experimental platform,select a time with sufficient light for experimental verification,and sample the output voltage,output current and output power of the PV panels every hour.Finally,this paper combines the simulation results in MATLAB with the results measured in the experimental platform,and verifies the feasibility of the MPPT control strategy under constant DC bus voltage by analyzing the waveforms and data.The research content of this paper can provide some reference value for future researchers who study MPPT in DC bus photovoltaic system,especially the MPPT control strategy under DC bus voltage variation.