| With the rapid development of high-speed railways in China,the focus of high-speed railway construction in China has gradually shifted from the eastern plains to the more complex western regions.The terrain in China’s western region is complex,mainly composed of plateaus,mountains,and basins,with significant topographic relief.Therefore,in order to avoid unfavorable geology,overcome plateau obstacles,reduce construction difficulties,and save project investment,it is necessary to consider using long ramps during railway construction.Taking the V/v traction power supply system as an example,the issue of regenerative braking energy recovery and utilization in long ramp sections is studied.The specific research content is as follows.(1)Through the research on the data of the long gradient section and the analysis of the train forces in the long gradient section,it is found that the train has a large amount of braking energy and may not be able to safely pass the electrical phase-separation in the long ramp section,thus proposing the use of energy storage to connect to the traction power supply system to realize the recycling of regenerative braking energy and ensure that the train does not over electrical phase-separation.By analyzing the regenerative braking energy utilization scheme and the train uninterrupted phase-separation passing scheme of the high-speed railroad,the topology of the traction power supply system is established based on the railroad power regulator and supercapacitor energy storage system for the long ramp section.(2)By analyzing the topological components of the energy storage connected to the traction power supply system,the equivalent modeling methods of the traction power supply system,railway power regulator,supercapacitor energy storage system and train uninterrupted phase-separation passing system are proposed,and the parameters of the LCL filter in the uninterrupted phase-separation passing system are analyzed and designed.The simulation models of traction power supply system,railroad power regulator,supercapacitor energy storage system and train uninterrupted phase-separation passing system are established in Matlab/Simulink to provide a basis for the overall simulation model of regenerative braking energy recovery and train uninterrupted phase-separation passing in long ramp section.(3)Aiming at the problem of a large amount of regenerative braking energy in the long ramp section,an energy management strategy based on the charging and discharging threshold of the energy storage system is proposed by analyzing the compensation principle of the railroad power conditioner and the supercapacitor energy storage system,dividing the working conditions according to the charging and discharging state of the supercapacitor energy storage system,and analyzing the harmonic suppression principle and the power flow under various working conditions.Through setting simulation of working conditions and verification in the semi-physical simulation platform Star Sim HIL.The results show that the railroad power regulator-supercapacitor energy storage system can realize the recovery and utilization of regenerative braking energy,and at the same time manage the characteristic second harmonic in the traction power line system to improve the power quality of the traction power supply system.(4)Aiming at the problem that trains speed reduction in the uphill section of long ramps may lead to the train not being able to safely over-phase,an uninterrupted phase-separation passing control strategy based on a single-phase virtual synchronous generator is proposed by analyzing the principle of uninterrupted phase-separation passing of trains.Considering the charge state of the energy storage system,the working condition of trains over-phase is divided and its power flow is analyzed.By setting and simulating the train’s phase transition conditions,and verifying them in the semi-physical simulation platform Star Sim HIL.The results show that the proposed single-phase virtual synchronous generator-based uninterrupted phase-separation passing control strategy can support the voltage and frequency on the neutral line,control the power flow of the train and utilize the regenerative braking energy in the energy storage system.The neutral line voltage phase can be controlled to realize the train’s uninterrupted phase separation passing. |
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