Research On Energy Management And Operation Control Of Wind-PV-ES Micro-grid System

In today's world,the energy crisis is aggravating.Since fossil fuels such as oil and coal are eventually dry up because of their unsustainability,the energy issue is increasingly becoming a severe challenge for all countries in the world.Various types of distributed power sources are included in the microgrid.How to effectively coordinate the output of distributed power sources,reasonably allocate resources,achieve the goals of renewable energy optimization and minimum loss has become a hot research topic in the economic operation of micro-grids.When the internal structure of the microgrid is changed,how to design a micro-grid control strategy according to the requirements of operation according to the characteristics of the distributed power source and effectively coordinate and control each distributed power source in the micro-grid is the key to to reliable operation of micro-grid.Based on the above research background,this paper studies the two aspects of energy management and operation control of Wind-PV-ES micro-grid system.According to the different characteristics of island operation and grid connectedoperation of microgrid,two different energy optimization modes are proposed.In the independent mode,considering the economy and reliability of the microgrid,under the premise of ensuring the local load demand,the objective function is constructed with to minimize the total generation cost and optimize it.In the grid-connected mode,on the basis of the research on the regularity and characteristics of the changes of wind turbines,photovoltaic and storage batteries as well as the demands of users,taking into account the uncertainties and differences in supply and demand at each moment,a sub-period microgrid energy optimization management model considering grid electricity price is constructed.Analysis of the power generation principle of wind power generator,photovoltaic and storage batteries.The simulation model of these three kinds of micro power supply is constructed,and the simulation of the model is carried out.Among them,to realize the full use of wind energy and light energy in nature,the control strategy of the wind turbine side adopts the zero d-axis current control strategy,the photovoltaic power generation system adopts the perturbation observation method to track the maximum power point.According to the different roles of the battery energy storage system in grid-connected operation and island operation of the microgrid,two control strategies are designed for the bi-directional Buck/Boost converter to achieve charge and discharge control.Aiming at PQ and V/f,these two kinds of grid-connected inverters control strategies,the control principlesare analyzedand the simulation modelsare constructed for them.And the overall operation strategy of microgrid system is elaborated in detail.Finally,a miniature Wind-PV-ES micro-grid model is set up in MATLAB/Simulink.Through thesimulation of micro-grid when it operated in grid-connected model and island model,including the change of the output power of the photovoltaic and the wind power generation system,the change of the charge and discharge of the battery energy storage system,and the change of the load demand,etc.The simulation analysis of the dynamic process in the micro-grid of different operating states and the switching state of the operating state,the simulation results verify the rationality of the micro-grid model and the feasibility of the control strategy adopted in this paper.