Research And Development On Grid-connected Photovoltaic Based Microgrid Optimization Control System

Under the dual challenges of energy-saving emission reduction and energy security,making great develop and full use of new energy is an important way to achieve sustainable development.New-energy-used microgrid,especially photovoltaic microgrid as a strong complement to currant power system,are arouse wide attention.Photovoltaic microgrid not only increase utilization of light resources,but also effectively improves the stability and economy of local power supply system.With the gradual development of microgrid technology,there are increasing types of equipment for photovoltaic microgrid.The deviation of load forecast,along with the uncertainty of single time scale will cause the reduction of economic efficiency on microgrid operation.Therefore,designing a set of optimized control systems which can ensure the safety and stability of microgrid operation,as well as improve the efficiency of renewable energy,has become top priority.At the beginning,the paper analyzes the working principle,grid connecting structure and operating characteristics of each integrated unit of grid-connected photovoltaic microgrid in detail,deduction establishes a reasonable and accurate mathematical model of each unit.Secondly,the control principles and methods of the operation status on photovoltaic microgrid in grid connection will be studied.On this field,this paper conducts the formulate appropriate optimal control strategies for achieving three objectives including maximizing the economics,maximizing environmental benefits,and optimizing stability of the photovoltaic microgrid.Furthermore,the paper establishes a grid-connected operation mode to minimize operating costs,and the control model with the greatest environmental benefit,and converted into the optimization target model with the most comprehensive benefit.Moreover,on the basis of comparative analysis of various optimization algorithms,this paper proposes an optimization algorithm,which combines mixed integer linear programming and improved particle swarm optimization.It can effectively solve two kinds of problems that are prone to occur in the calculation process: First of all,the variable convergence speed is slow.Then,the optimal solution is easy to fall into the local optimal.At the same time,combined with the photovoltaic system operation data and meteorological data of a certain research institute in 2019,Matlab tools were used to sequentially simulate the operation strategy of the optimized control model in different working conditions.By comparative analysis the comprehensive benefits before and after adopting the model,this paper verifies the effectiveness of the optimized control algorithm and model.Finally,based on the constructed optimized control algorithm and model,a small photovoltaic microgrid optimized control system is made.The hardware part of the control system uses PLC as the core of the execution control,and the software part is developed using the Win CC platform,and the two communicate through Ethernet.The system can not only realize the control and monitoring of the components of the photovoltaic microgrid,but also reduce the system response time through multi-thread control,ensure the stable operation of the microgrid under various working conditions,and maximize the comprehensive benefits.