Research On MPPT And Energy Coordination Control Based On Photovoltaic Microgrid

With the increasingly severe global energy shortage and environmental pollution issues,the development and utilization of clean and pollution-free renewable energy has gradually gained public favor.As a new type of power generation and distribution system,the DC microgrid can effectively utilize new energy for power generation and Compensate for the drawbacks of traditional energy sources.However,due to the impact of external factors,the instability and volatility of renewable energy power generation are extremely prominent.If it is not processed and directly integrated into the large grid,it can be counterproductive.Therefore,in-depth research on microgrid technology is the main way to solve this problem.The research content of this article focuses on distributed photovoltaic power generation modules,hybrid energy storage modules,and other main research objects.It aims at expanding research on photovoltaic maximum power point tracking(MPPT)control technology and energy coordination control strategies.The main work content is arranged as follows:Firstly,the principle,model,and related characteristics of photovoltaic power generation are briefly introduced,and corresponding mathematical models are established for photovoltaic arrays.Based on the MPPT control principle,various commonly used MPPT algorithms are compared and analyzed;Further analysis and comparison of various energy storage modules,the use of supercapacitors and battery devices to form a hybrid energy storage system,and a brief description of its working principle and equivalent model,based on which to establish their respective simulation models for detailed analysis;Subsequently,the working principle of the DC-DC converter is described,and its control strategy is designed to control the charging and discharging state of the energy storage system.The effectiveness of the proposed method and strategy is verified through the establishment of a simulation model.Secondly,an improved Grey Wolf Optimizer(IGWO)MPPT control based on Particle Swarm Optimization(PSO)optimization is proposed to solve the problem that traditional maximum power tracking algorithms cannot jump out of the global optimization and find the maximum power under local shading.The algorithm introduces the idea of PSO location update on the updated location of the gray wolf,thereby reducing the possibility of the algorithm falling into local optimization.At the same time,in order to achieve local optimization,a small step perturbation observation method is introduced to accurately search for the maximum power point.In order to prevent premature convergence and loss of diversity of wolf packs in the later stages of the algorithm,Levi flight is used to α conduct a global search for wolves.The advantages of the proposed algorithm are verified through simulation analysis with traditional algorithms under various operating conditions.Finally,based on the above control strategy,in order to improve the power quality of the system connected to the grid and reduce the fluctuation and impact of the DC bus voltage,an improved Active Disturbance Rejection Control strategy composed of hybrid energy storage is proposed,which realizes constant current charging and discharging of the energy storage control unit based on controlling the operating conditions of the bidirectional DC-DC converter of the energy storage system,And then make up for the shortcomings of traditional PI control systems.According to the control objectives of the system,based on the consideration of overcharging and discharging of energy storage devices,the microgrid is divided into four operation modes.Several numerical examples are used to verify the steady-state performance and transient performance of the proposed strategy during various mode switching processes.The final results show that the proposed control method can stabilize the DC bus voltage and smoothly switch between the four operating modes,while also improving the service life of hybrid energy storage devices.