Research On Control Strategy And Capacity Configuration Of Wind Power-Hybrid Energy Storage Combined System

In order to deal with the exhaustion of fossil energy and environmental protection issues,wind power generation technology has been developed rapidly in recent years.However,large-scale grid integration of wind power will damage the power quality,economy,safe and stable operation of the power system.Hybrid energy storage technology has the characteristics of high energy density and fast power response,which can effectively smooth wind power fluctuations at different time scales and improve system economy.Therefore,this paper takes the wind power-hybrid energy storage combined system as the research object,deeply studies the operation control strategy of the wind energy storage system and the configuration method of the hybrid energy storage capacity,and proves the effectiveness of the proposed scheme through simulation and data analysis.The main research contents include:(1)Established a wind power-hybrid energy storage combined system structure suitable to smooth the wind farm grid-connected power fluctuations.Firstly,this paper summarizes and analyzes the technical and economic characteristics of the current energy storage medium,and determines the use of lithium-ion battery and supercapacitor to construct the hybrid energy storage system.Secondly,by analyzing the typical structure of the power conversion system and the energy storage access modes in wind farm,the common DC side topology of DC/DC and DC/AC converters with good comprehensive performance and energy storage centralized access mode are adopted.Finally,the physical structure of the combined system is established.(2)In order to control the grid-connected power volatility of the wind-storage combined system to meet the grid-connected standards,this paper firstly proposes a dynamic generation strategy for the grid-connected target power of the wind-storage system.This strategy generates the grid-connected target power with hysteresis based on the real-time wind power sequence.Secondly,an online control strategy for grid-connected power volatility based on model predictive control is established.This strategy takes the grid-connected volatility limit and the energy storage model as constraints.While tracking the above target power,it implements receding optimization at each moment to generate energy storage power.Simulation shows that the proposed control strategy can strictly control the grid-connected power volatility of the combined system under various wind conditions,and avoid the long-term accumulation of unbalanced energy in energy storage.(3)A hybrid energy storage power allocation strategy based on adaptive filtering algorithm is proposed.This strategy first uses variational mode decomposition to analyze the total power task signal of energy storage in frequency domain,and then combines fuzzy control and filtering algorithms to feed back the state of charge of supercapacitor energy storage,completes the adaptive adjustment of the primary frequency domain point,so as to give play to the technical and economic characteristics of different energy storage media,and reduces the capacity configuration requirements of super capacitor energy storage.(4)An energy storage capacity configuration process is proposed and an energy storage system economic cost evaluation model is established.This paper uses simulation analysis and theoretical calculations to verify the configuration of the hybrid energy storage capacity to determine the final configuration plan.On this basis,the rain flow method is used to analyze the equivalent cycle life of battery energy storage and establishes an energy storage life cycle cost evaluation model.The simulation results show that the hybrid energy storage system established in this paper has good technical and economic value.