Research On Enerrgy Recovery Technology Of Supercapacitor In Urban Rail Transit

The development of urban rail transit can alleviate urba n traffic congestion and improve urban air quality.Due to the short distance between the city rail station and the station,the city rail trains start frequently and consume a lot of energy and release a lot of energy In the process of starting and braking.If the energy generated during the braking time can be used for city rail trains start-up,it will save a lot of electricity.Firstly,Combined with the characteristics of urban rail transit train starting and braking,the bidirectional DC / DC converter is chosen as the topology of the main circuit converter of the energy storage feedback braking system.And I also make research on the energy released during the breaking process,the energy used to calculate the size of the super capacity system is generated by the difference,which is the initial kinetic energy of the train minus the friction work between the tracks.Secondly,The converter system is modeled by using the state-space method and treating the super capacity and the b idirectional DC/DC converter as a system,Mathematical model of this rectifier topology is derived and control parameters of the control system are designed,which uses voltage-current double closed loop PI control method,the energy storage device is simulated in the state of charge and discharge by using the MATLAB/SIMULIK software.Finally,the super capacitor energy storage system model,traction substation model and train model are integrated to form a super capacitor energy storage system,the city rail vehicle start and brake is simulated by controlling the motor running mode to observe the influence of the train on the voltage of the power supply system under the condition of energy storage feedback system and no energy storage feedback system.This paper combines the influences of urban rail train starting and braking on the power supply network voltage and the low rate of the regenerative brake,proposing to collect the energy generated during the train braking in the super capacitor for the train restarts.This makes up for the power supply network voltage reduction caused by the start of the train and power grid voltage rise caused by the braking and avoids the lower energy conversion rate of the regenerative brake limited by the power supply network voltage rise.