Research On Control Strategy Of Hybrid Energy Storage Assisted Wind Power Smoothing Power And Primary Frequency Modulation

Under the strategic goal of "3060 double carbon",new energy has gradually and deeply participated in building a clean energy system.As a clean energy with broad development prospects and relatively mature development,wind power has become the third largest power source in China.However,the power random fluctuation caused by the continuous growth of wind power grid connection capacity poses new challenges to the stable operation of power system and primary frequency regulation.As flexible regulation resources,new energy storage technologies such as flywheel and electrochemical battery have the characteristics of rapid response,making them an effective means to assist wind power grid connection.In recent years,the related issues of Hybrid Energy Storage System(HESS)have become a research hotspot.Therefore,in the context of hybrid energy storage auxiliary wind power for power smoothing and primary frequency modulation,this paper conducts in-depth research on the control strategy of hybrid energy storage system.Firstly,the relevant performance parameters of different energy storage system technologies are compared and analyzed,and the flywheel and lithium battery with relatively suitable performance parameters are selected to form a hybrid energy storage system,and the mathematical model and frequency modulation simulation model of the flywheel and lithium battery are established.Secondly,the common control strategies of primary frequency regulation in wind farms are analyzed,and the limitations of existing control strategies are found.In order to make up for the deficiencies of the original control strategies,give full play to the advantages of flywheel energy storage frequency regulation,and improve the primary frequency regulation ability of wind farms,the segmented adaptive control strategy of primary frequency regulation considering wind power permeability and the virtual droop coefficient fuzzy control strategy considering the mixed energy storage state of charge are proposed.The simulation results show that the proposed control strategy can make the wind farm adjust its output automatically in response to the change of wind power permeability,improve the inertial response ability of primary frequency modulation,and reduce the maximum and steady-state frequency deviation.Finally,on the basis of combing the relevant requirements of the active power of wind power grid-connected operation,and taking into account the smoothing effect of wind power and the state of charge(SOC)of mixed energy storage as the control objective,a three-step control strategy based on particle swarm optimization parameters,namely,the variational mode decomposition algorithm for decomposing the fluctuating power of wind power,the power correction control based on different SOC zones of energy storage,and the coordinated control of the actual power of energy storage,is proposed.An example shows that the proposed control strategy can balance the state of charge of energy storage while ensuring the smooth effect of wind power,and greatly reduce the depth and frequency of charging and discharging of lithium battery to optimize its operation performance and life.