Research On Simulated Inertia Coordination Control Strategy Of Virtual Power Plant Based On Distributed Energy Storage

With the introduction of smart energy and energy Internet and the continuous improvement of distributed energy permeability,virtual power plant is proposed as an energy aggregation model on the basis of micro grid and active distribution network.However,large-scale distributed energy supply through power electronic devices leads to the reduction of overall inertia of the system and the decline of power-frequency stability of the system.The charging and discharging process of the energy storage system itself has inertia,which can effectively improve the power quality and system stability.Based on the natural science foundation project "research on simulation inertia coordination control mechanism and optimal allocation of network nodes of virtual power plant based on distributed battery energy storage system",this paper studies the inertia of energy storage system and its multi-machine simulation inertia control strategy.Aiming at the requirements of coordinated operation and power response of distributed energy storage simulation inertia control in VPP of virtual power plant,this paper studies virtual synchronous machine control of converter control strategy.Firstly,the control structure of converter and filter circuit are introduced.According to the principle and mathematical model of VSG control,the small signal model and off-grid characteristics of VSG control under grid-connected operation are analyzed,and the influence of inertial parameters on the system and the selection method are given.Secondly,the characterization method of inertia of the energy storage battery body under different energy storage media is derived,the characterization principle of the overall simulation inertia of the energy storage system is analyzed,and the simulation results are verified.An improved VSG control strategy based on the inertia of the energy storage body is proposed to give full play to the inertia of the energy storage system and improve the response speed of the control system.According to the power distribution mechanism of multi-machine parallel connection,the deficiency of traditional VSG control in power distribution when line parameters are inconsistent is analyzed,and the power distribution principle of virtual impedance is studied.On the inertia control of multi-machine system,a coordinated control method of inertia adjustment based on the principle of power distribution of multi-machine system is proposed.Thirdly,the small signal model of the system is built for the stability of the multi-machine system,and the influence of the change of inertia parameters on the stability of the multi-machine system is analyzed.According to the result of the influence of the change of inertia parameters on the stability,the inertia parameters are selected.The real-time simulation system of single-machine energy storage system and multi-machine energy storage system was analyzed and verified in MATLAB.Finally,based on the rt-lab semi-physical simulation platform,the main circuit and hardware circuit of the system are built,the simulation inertia control program is written,and the distributed energy storage simulation inertia control strategy is verified and analyzed.The rationality of the control strategy is further verified by the hardware in the loop semi-physical simulation platform.