Research On Modeling And Simulation Methods Of Photovoltaic Microgrid And Photovoltaic Power Plants

With the rapid development of smart grids,microgrids are considered to be an important part in reducing energy consumption and improving reliability and flexibility of power systems.Research and practice show that the use of microgrids to access and manage renewable energy power generation systems such as photovoltaic power generation can effectively solve technical problems such as indirect,random,and poor controllability of such power supplies.Therefore,this dissertation builds a photovoltaic microgrid system modeling platform to solve the key issues encountered in the large-scale application of photovoltaic microgrids.The main research work and achievements of the paper are:This dissertation describes the significance of large-scale application of photovoltaic microgrids before introducing the basic components of photovoltaic microgrids and analyzing the basic control methods of microgrids.Secondly,The theoretical PWM control converter optimization simulation model based on averaging is proposed in order to improve the simulation efficiency of photovoltaic grid-connected inverter systems..Thirdly,it deduced the system state equation subsection average equation.Finally,the accuracy of the average method modeling can be verifiedthrough the analysis of boosting chopper circuit examples.In order to solve the problem of delay in the switching between photovoltaic microgrids control mode switching and grid-connected switching,a method for centralized control of photovoltaic microgrids dual-mode operation was designed by using the averaged optimization simulation model of the converter.When the microgrids are running off-grid,the energy storage system acts as the main power source,and Vf control is used to keep the voltage and frequency stable.When the microgrids are connected to the grid,both the photovoltaic power source and the energy storage unit adopt PQ control;When the signal is connected to the network,the off-grid operation mode is switched to the on-grid operation mode through the grid-connected control;when the PV micro-grid receives the off-grid signal,the off-grid control exits from the on-grid operation and then goes off-grid operation.Through the four key control functions in the dual-mode operation,the dual mode operation capability of the photovoltaic microgrids is improved.The simulation results show that:using the designed control scheme,the photovoltaic microgrids can achieve a smooth switching of the operating mode,there is no obvious impact transition process,and the system runs smoothly and reliably.In order to connect large-scale photovoltaic microgrids to the grid,a coordinated control method for photovoltaic power plant clusters was studied.Through the coordinated control of multiple photovoltaic power plants in large areas,the output power of the cluster terminal was stabilized.In order to improve the fine-tuning capabilities of photovoltaic power plant clusters,make full use of the coordination and complementary capabilities of photovoltaic power plants and improve the efficiency of solar energy utilization,a proportional distribution algorithm and an optimized distribution algorithm for active power control of photovoltaic power plant clusters are proposed.The feasibility of cluster active power control methods.A photovoltaic micro grids system modeling platform was constructed to provide a good tool for modeling the subsequent photovoltaic microgrids system.The theoretical research results of this dissertation provide a rapid modeling method to solvethe detailed modeling and simulation problems of large-scale photovoltaic microgrids.When the application platform is used for modeling and simulating large-scale photovoltaic microgrids,the simulation model of the automatic calculation example can be auto generated if the key simulation parameters can be provided,which will greatly improve the efficiency and flexibility of simulation modeling.