Research On The Hybrid Control Strategy Of Peak Regulation And Frequency Modulation For Energy Storage System Based On The SOC Optimization

In order to deal with the problems caused by environmental pollution and resource shortage of traditional fossil energy power generation,more and more renewable energy systems have joined the power system.Admittedly,these renewable energies,with their advantages of high efficiency,green and renewable,are to some extent an effective alternative to traditional fossil energy power generation.However,renewable energy is not without disadvantages.It is greatly affected by the environment,so it has great uncertainty and imbalance in both time and space scales.The fluctuation of renewable energy power generation will also lead to the fluctuation of power and frequency of the power system,which will have a negative impact on the power system,and even cause the collapse of the power system in serious cases.Therefore,in order to deal with the problems brought by renewable energy power generation,the development of energy storage system has received more and more attention.Energy storage system is considered as an effective means to solve the uncertainty and imbalance of renewable energy system because of its high flexibility,fast response speed and two-way regulation characteristics.The development of energy storage system is an important part of building a low-carbon energy system and achieving the " peak carbon dioxide emissions and carbon neutrality" goal.In order to maximize the functionality and economy of the service function of the energy storage system,this topic takes the control strategy of the battery energy storage system as the research object,and proposes a hybrid control strategy of frequency modulation and peak modulation of the energy storage system based on the optimization of the state of charge(SOC)of the energy storage system.Through the comparison of the performance and economic indicators of different kinds of energy storage systems,this paper expounds the reasons for choosing lithium-ion battery as the research object.specifying multiple partitions for the SOC of the battery energy storage system.In order to prevent the battery energy storage system from being damaged by overcharging and discharging,the allowable operation of the battery energy storage system when it is in a certain zone is specified to extend the service life of the battery energy storage system and reduce the operation,maintenance and replacement costs of the battery energy storage system.Then,aiming at the frequency modulation function of energy storage,an improved droop control method based on the Kuramoto Model is proposed.Compared with the traditional droop control strategy,the improved droop control frequency modulation strategy based on the Kuramoto Model further considers the impact of renewable energy output.Then,according to the peak regulation function of energy storage,the peak shaving and valley filling of renewable energy power system will be realized.For the SOC self-recovery optimization control method of battery energy storage,based on constant power recovery strategy and Battery SOC Holder control strategy,a SOC self-recovery optimization control strategy is proposed,and the power system scope of battery energy storage for SOC self-recovery is specified.Afterwards,the SOC zoning,frequency modulation function,and peak regulation function of the battery energy storage system mentioned above will be combined,while considering the power system frequency,peak environment,and the SOC state of the BESS to determine the appropriate output of the BESS.On the premise of ensuring the stability of the SOC of the BESS,the requirements of the BESS for the frequency modulation and peak adjustment of the power system will be realized.For the required power of battery energy storage frequency modulation,peak regulation and SOC selfrecovery,different weights are given to realize the common realization of multiple functions of battery energy storage system,and improve the utilization and economy of battery energy storage system.Finally,the simulation of each part and the whole of the control strategy is carried out,which proves that the power characteristics,frequency characteristics and SOC characteristics of the system are optimized when the control strategy is applied to the battery energy storage system,and proves the rationality and feasibility of the frequency modulation and peak modulation hybrid control strategy of the energy storage system based on SOC optimization.