Research On Improved Maximum Power Point Tracking Technology For Photovoltaic System

In recent years,solar photovoltaic power generation has become one of the main ways to solve the energy crisis and environmental pollution.The photovoltaic system has many advantages such as clean,high efficiency and abundant reserves.In order to increase the output power of photovoltaic power generation and increase the annual power generation of photovoltaic power generation systems,the system generally adopts Maximum Power Point Tracking(MPPT)control.At present,the commonly used MPPT control technology generally has disturbance observation method and conductance increment method.Although the system can be controlled to achieve MPPT operation,on the one hand,there is always disturbance during the operation of the system,which results in poor output power quality.When it changes rapidly(such as the photovoltaic panel is blocked in cloudy weather),it is easy to cause tracking failure and reduce the annual power generation of the system.Therefore,the existing MPPT technology still needs to be optimized and improved to improve MPPT tracking performance.This dissertation takes photovoltaic power generation system as the research object,mainly to improve the existing MPPT technology in order to improve the MPPT operation performance of the system in view of the rapid change of light intensity.The main research content package of the dissertation:First,review the commonly used solar power generation system structure,and select the common photovoltaic power generation system structure as the research object of this paper.By modeling the photovoltaic power generation system,especially the photovoltaic cell,the performance of the solar power generation system is analyzed,which lays the foundation for MPPT control analysis.Afterwards,the working principle of commonly used disturbance observation and conductance incremental MPPT control methods are discussed.The tracking performance of the light intensity is rapidly changed,and it is pointed out that the existing methods are easy to track the cause of failure when the light intensity changes rapidly.In order to solve this problem,the existing disturbance observation method is improved,and its tracking performance is analyzed.The improved method can effectively improve the tracking speed of the system when the light intensity changes rapidly.Then,a set of 60 W photovoltaic power generation system was designed in detail,including main circuit parameters and control system parameters.And based on the design parameters,a simulation platform was established in MATLAB/Simulink,and the system was simulated,and the results verified the correctness of the improved MPPT method.Finally,the full dissertation is summarized and the future work is prospected.