Research On Energy Storage Scheme And Its Control Strategy For Regenerative Energy Recycling Of High-speed Railway

The high-speed EMUs widely applied the regenerative braking technology.During the braking process,the kinetic energy of traction motor can be converted into electric energy and fed back to the power supply system without compensation,which brings a large number of economic losses to the railway sector.Also,the high-speed EMU has the characteristics of high power,single-phase and non-linearity,which brings power quality problems such as harmonics and negative sequence,so that the safe and stable operation of traction power supply system is threatened.Based on this,combined with the operation mechanism of traction power supply system of high-speed railway,this paper establishes an accurate coupling model of EMU-traction power supply network,and the energy flow path of vehicle-network coupling system under typical working conditions is analyzed.Furtherly,considering the demand for power quality optimization and regenerative braking energy recovery,an AC-DC-AC based model is designed.The regenerative energy recovery scheme of flow technology is studied,and the corresponding control strategy and optimization technology are studied.The main research contents are as follows:(1)An accurate model of EMU-traction power supply system high-speed is established,and the energy flow characteristics under different working conditions are analyzed.Combining with the topological structure of the AT traction power supply system of highspeed railway,the working principle of V/x traction transformer is introduced,and the equivalent parameters calculation method of traction network is deduced.For high-speed EMU,the topological structure and control objectives of the grid-side converter and motorside converter in the traction drive system of EMU are analyzed.The transient current method is used to control the grid-side converter.Vector control based on rotor field orientation is selected to realize frequency conversion and speed regulation of traction motor.Based on the simulation platform of MATLAB/Simulink,the vehicle-network coupling model is built.On this basis,the energy transmission characteristics and power quality characteristics of the traction power supply system under typical operating conditions are analyzed.(2)Based on AC-DC-AC converter technology,the regenerative energy recovery scheme of the traction power supply system is designed.The AC-DC-AC converter is introduced between the left and right power supply arms of the traction substation,and the energy storage device is connected to the DC link of the converter through the bidirectional DC/DC converter.On this basis,the energy transmission characteristics of the traction power supply system with an energy storage device under four typical operating conditions is connected are analyzed.In order to provide a stable DC voltage for the access of the energy storage device,balance the load of two arms and compensate the negative sequence current and harmonic current of the traction substation,the control strategy of the converter is designed.The simulation results show that the control strategy can not only realize the recycling of regenerative energy but also suppress the harmonic and negative sequence problems of traction power supply system effectively.(3)For energy management of energy storage devices,a dynamic power charging and discharging strategy based on Super-capacitor charging state are proposed.A model of energy storage device for traction power supply system of the high-speed railway is established.The topology and control method of the bidirectional DC/DC converter are analyzed.Based on traditional closed-loop control strategy,a dynamic power energy management strategy based on charged state is proposed to realize the smooth transition of current when the state of the energy storage medium is switched over.The energy storage scheme and energy are demonstrated by simulation analysis.The correctness of management strategy.On this basis,the regenerative braking power and energy distribution law of Xicheng High-speed Railway Guangyuan Substation are analyzed based on 24-hour measured data.Based on this configuration,the rated capacity and charging and discharging power of the super-capacitor are allocated,and the charging and discharging thresholds of the super-capacitor are set.Finally,the energy-saving effect and dynamic power of the energy storage system are analyzed with the measured data.The effectiveness of rate energy management strategy.(4)A low power experimental platform for high-speed railway energy storage system is developed.Combining with the topological structure of the energy storage scheme,the overall framework of the experimental prototype is proposed.The components of the traction power supply system,AC-DC-AC converter,and energy storage device in the experimental platform are analyzed.Based on the control strategy proposed in Chapter 3,the control system of the experimental platform is designed,and the formulas for calculating the experimental parameters of each component are derived.Finally,the operation of the experimental platform is given.The results were tested and analyzed.Finally,the work of this paper is summarized,and the shortcomings of this study have prospected.