Research On MPPT And ADRC Grid-connected Control Strategy Of Photovoltaic Power Generation System

With the continuous deterioration of energy crisis and environmental problems,photovoltaic power generation has received extensive attention.However,the development of photovoltaic power generation still faces many problems that need to be solved urgently.One is: how to ensure that the photovoltaic system can output power in real time at the maximum power point,so as to ensure the full utilization of light energy.The second is to choose an appropriate control strategy to deal with the randomness and fluctuation of photovoltaic power generation(light intensity,ambient temperature,etc.),and the bus voltage stability problem caused by it.The paper firstly introduces the research background and significance of the subject,analyzes the current situation of the scale of photovoltaic power generation industry at home and abroad,and discusses the research status of the maximum power tracking technology in photovoltaic grid-connected control and the control strategy of photovoltaic grid-connected inverters.Secondly,the traditional maximum power tracking control is analyzed,focusing on the multi-peak phenomenon of the output characteristics caused by the series-parallel and cloud effect of photovoltaic cells.In order to solve the problem of maximum power tracking when the output characteristics of photovoltaic power generation systems exhibit multiple peaks under partial shadows,an improved particle swarm optimization algorithm was proposed.It improves tracking performance by optimizing inertial weights and introducing sensitive particles.The improved particle swarm algorithm is introduced in the maximum power tracking of photovoltaic systems,The simulation results show that the improved particle swarm algorithm can accurately track the peak value of the system when the external conditions change,which solves the problem that the traditional method is easy to fall into the local optimum.Finally,in view of the fact that the DC side bus voltage of the photovoltaic grid-connected inverter is easily affected by light,temperature and load fluctuations,an ADRC control strategy based on the Reduced Linear Extended State Observer(RLESO)is proposed;It is applied to the outer voltage loop of photovoltaic grid-connected inverter.The mathematical model of photovoltaic grid-connected inverter in d-q coordinate system is established,and RLESO is designed on this basis,and the convergence of RLESO is proved by constructing Lyapunov function.The frequency domain characteristics show that RLESO has faster response speed and smaller phase lag than Linear Extended State Observer(LESO).The simulation test of multiple working conditions is carried out through the Matlab/Simulink simulation platform,and the results show that the control strategy of RLESO has good rapidity and anti-interference ability,and is more practical in engineering.In order to improve the control accuracy and robustness of the system,the terminal sliding mode theory is used to replace the traditional linear error feedback law to design the error feedback law of the active disturbance rejection controller,and the observations of RLESO are used to design the terminal sliding mode controller.The advantages of the optimized control strategy are verified by simulation analysis of various working conditions.There are 36 pictures,3 tables,and 62 references in the article.