Research On Modeling And Optimizing Control Strategy Of Energy Storage Co-phase Power Supply System

The single-phase power frequency AC power supply system and traction load with high power and asymmetry of electrified railway have caused many problems,such as negative sequence,phase splits and regenerative braking energy feedback utilization,which affect the safe,reliable and efficient operation of electrified railway.The co-phase power supply system based on the symmetric compensation theory can effectively solve the problems of negative sequence and phase splits.Therefore,combined with co-phase power supply technology and energy storage technology,the reaearch on energy storage co-phase power supply system is carried out to comprehensively achieve the purpose of power quality control,regenerative braking energy feedback utilization and system capacity optimization configuration.The specific research contents are as follows:Based on the single-phase combined co-phase power supply system and the fast charging and discharging characteristics of supercapacitor energy storage device,an energy storage co-phase power supply system is studied.Constrained by negative sequence national standard limit value and aimed at regenerative braking energy feedback utilization and system capacity optimization configuration,the regenerative braking energy control mode,peak-cutting discharge mode and valley-filling charging mode of the system are analyzed.Meanwhile,the formulas for calculating the compensating power of the co-phase power supply device and the energy storage device ports under different working modes are deduced,and the method for calculating the switching threshold of the working mode of the system is given.The working effect of the system is analyzed by the measured data.The control method suitable for energy storage co-phase power supply system under various working modes is studied.A coordinated control strategy of upper compensation power calculation and lower converter control is proposed to complete the effective switching between different working modes of the system.The upper control includes load detection and mode judgment,the lower control includes co-phase power supply device control and energy storage device control,and predictive current control is introduced to make the system have better dynamic characteristics.Based on the MATLAB/Simulink simulation platform,the simulation model of the energy storage co-phase power supply system is built,and the operation characteristics of the system under different working modes and operating conditions are simulated and analyzed.Under the condition of meeting the national standard limit of negative sequence,the regenerative braking energy feedback utilization and peak-shaving of traction load are realized,and the expected compensation effect and good working characteristics are achieved,which provides technical support for the engineering application of energy storage in-phase power supply system.