Study On Wind Power Output Fluctuation Stabilization Method Based On Hybrid Energy Storage

In recent years,the development of new energy sources such as wind power and solar energy is rapid and the installed scale expands unceasingly.However,because of wind power output has a strong randomness,volatility characteristics.Therefore people often install form a complete set of energy storage system in a wind farm to smooth wind power output,so as to ensure the safe and stable operation of power grid after the wind power integration.According to the characteristics of wind power output,the hybrid energy storage system can be very good for smooth wind power output.However,the size of the capacity of hybrid energy storage system configuration will directly affect the wind power control effect and the efficiency of the whole system,and power control strategy of energy storage equipment will be directly related to the use of the energy storage equipment efficiency and service life.Based on this,this paper mainly studies the capacity allocation and power control strategy of the hybrid energy storage system.The main work is list as follows:Firstly,calculated and analyzed the amplitude-frequency characteristics of the output power of the wind farm and the wave quantity,then studied the principle of wavelet packet transformation.And on this basis,in terms of the requirements of wind farm output power fluctuation,the optimal level of the use of wavelet packet decomposition was determined through calculation,and then determined the wavelet function of wavelet packet decomposition this paper uses according to the wavelet function optimization method.Finally,decomposed and reconstructed the measured output power of the wind farm by wavelet packet,got the wave power signal of different frequencies.For different types of charging and discharging characteristics of different energy storage devices,the signals with different fluctuation frequencies are allocated to the lithium battery and the supercapacitor respectively.Secondly,the working principle and the characteristics of lithium-ion batteries and super capacitor are introduced and analyzed,and on this basis,set up the equivalent circuit model of lithium-ion batteries and the super capacitor.Then,studied the structure of the hybrid energy storage system,and introduces several kinds of the topology of the hybrid energy storage system,after comparative analysis identified,the topology of the hybrid energy storage system was determined in this paper.Researched and analyzed the working principle of hybrid energy storage system and the advantages of the hybrid energy storage system to smooth wind power output compared to a single energy storage system.Finally,the power and capacity allocation model of hybrid energy storage system was established.Then using wavelet packet decomposition method to decomposition and reconstruction the choosing historical wind power data,get different frequency fluctuations in power signal.According to the different charging and discharging characteristics of different energy storage component,the signals of different wave frequency separately are allocated to the lithium battery and super capacitor.Through the power and capacity allocation model of hybrid energy storage system,calculated the power and capacity allocation of the hybrid storage system.Thirdly,on the basis of the comprehensive consideration of the current working area of the energy storage equipment SOC and the charging and discharging of the energy storage equipment,design a kind of optimal coordinated control strategy which is based on wavelet packet decomposition-energy storage equipment SOC.Based on the current energy storage equipment SOC work area and the state of charge and discharge of storage equipment,discusses the two kinds of energy storage devices work,need and do not need to adjust energy storage device charge-discharge target power.Then in the case of need to be adjusted,according to the energy storage equipment for energy storage device charge-discharge SOC target power optimization control,wind power to tame and avoid the energy storage equipment working in charge discharge area,extending the service life of the energy storage device.