Stability Study Of Battery Energy Storage Power Converter System Based On LADRC-CD Control

Under the background of wide application of new energy power generation technology and energy storage technology,the subject will research on the stability of energy storage power converter system(PCS)in grid-connected working mode.For the impact of external disturbances such as weak power grids and harmonic power grids and internal disturbances on the stability operation of energy storage PCS,based on the impedance modeling analysis method,this topic is to improve the stability of energy storage PCS from the aspects of optimizing system parameters and improving control strategies.This topic provides analysis and solution ideas to promote the increase in the proportion of energy storage technology applications.The main research contents are as follows:Based on the working principle of energy storage PCS,determine and analyze internal and external disturbances that affect its stability.Linear active disturbances rejection control(LADRC)is used to achieve current decoupling(CD)control to eliminate the effects of internal disturbances.Compared with the PI-CD control strategy,the LADRC-CD control strategy not only uses fewer sampling sensors,but also has disturbance observation and compensation capabilities,making the energy storage PCS more stable under the influence of external disturbances.Because the unreasonable selection of filter parameters will affect the performance and stability of the energy storage PCS,this topic uses a Pareto multi-objective optimization algorithm based on artificial bee colony algorithm(ABC-Pareto algorithm).Optimize the parameters of the LCL filter to improve the performance of the energy storage PCS in dynamic response,high frequency harmonic current attenuation,etc.The obtained optimal parameter group provides multiple options for improving the stability of energy storage PCS under weak power grid.In the dq coordinate system,only the current inner loop is considered,and the output impedance model of the energy storage PCS based on the LADRC-CD control strategy is derived,which is compared with the PI-CD control strategy by drawing a Bode diagram.The LADRC-CD control strategy improves the stability of energy storage PCS running in weak power grids by introducing a compensation factor for grid impedance.Taking advantage of the weak sensitivity of the system stability margin to control parameters in weak power grids,the dynamic response speed of energy storage PCS and the robustness of power grids with lower frequency voltage harmonics can be improved by adjusting the control parameters reasonably.Aiming at the problem that high-frequency noise is apt to appear in the output observation value of the linear extended state observer,this topic introduces a pre-low-pass filter to improve the traditional state observer and optimize the observation performance.On this basis,the observation is used as the feed-forward quantity to realize the impedance reshaping control based on the LADRC-CD control strategy.Further improve the stability margin of energy storage PCS under weak power grid and its robustness to harmonic power grid.Through the theoretical analysis of the full text and summarizing the rules,a reasonable control parameter setting method is obtained,which is convenient for simulation and experimental debugging.Build energy storage PCS circuit model in MATLAB/Simulink software to realize basic battery charge and discharge function operation and current decoupling control strategy debugging,obtain and analyze simulation waveforms under various non-ideal power grids.The energy storage PCS experimental platform was built in the laboratory,and the obtained experimental results were consistent with the simulation waveform and theoretical analysis,which proved the advantages of the LADRC-CD control strategy in improving the stability of the energy storage PCS.