Research On Optimal Control Strategy Of AC/DC Microgrid Based On Situation Awareness

With the continuous growth of wind power,photovoltaic and other renewable energy in the proportion of energy,the use of microgrids including distributed power sources is the future development trend of the power industry.Due to the alternating and random nature of distributed power sources,the introduction of microgrids into large grids has a great impact on the operation of the grid.Therefore,the optimal control of AC and DC microgrids has always been the focus of microgrid research.The research on optimization control of AC/DC microgrid based on situational awareness proposed here is intended to make the operation of AC/DC microgrid more stable.The main tasks completed in this paper are as follows:(1)The framework of microgrid situation awareness is proposed,which includes four parts:data source,short term scenario analysis,continuous time sequence ultra short term prediction and operation situation assessment.The AC / DC microgrid model is built,and each part of the microgrid is modeled.The principle,characteristics and mathematical model of photovoltaic and wind power generation are described.A hybrid energy storage method is proposed by combining battery and super capacitor.(2)PV and wind power forecasting technologies based on physical and numerical models are respectively proposed.Analyzed the approximate daily model,wavelet analysis and neural network technology,and proposed a photovoltaic power generation forecasting technology based on wavelet analysis and neural network.The forecast was completed using the similar day principle,and simulation analysis was performed;the wind power physical model prediction and numerical model wind power prediction were analyzed,Proposed a combination of physical and statistical wind turbine forecasting technology,and carried out simulation analysis to verify the accuracy of the proposed forecasting technology.Then,the typical scenarios of microgrid are constructed according to the historical data,and the similar scenarios are found by comparing the prediction data with the historical data,which provides the basis for the control of microgrid.(3)The hierarchical control of microgrid is described,and the control strategy of AC / DC microgrid islanding and grid connection is proposed.Through the combination of independent control and centralized control,the hierarchical control is more flexible.The AC / DC sub network control,microgrid layer control and distribution layer control are analyzed by adjusting factors.The energy storage system is used for power distribution.The objective function of microgrid optimization is proposed.According to the typical scenarios of microgrid,the microgrid is optimized and controlled.Finally,the operation of microgrid system is simulated by MATLAB to verify whether the control strategy can make microgrid operation more stable.In this paper,through the establishment of microgrid model,the situation awareness of microgrid system is analyzed.Compared with the physical model and statistical model of wind power and photovoltaic,the power of power generation is predicted.It is concluded that the prediction result of the combination of physical model and statistical model is more accurate.Based on the historical data,the typical operation scenario of microgrid is established,and the operation control strategy of microgrid is proposed to simulate the operation of microgrid.