Research On Regenerative Braking Energy Recovery System For Subway

The distance removing subway stations is close,and the acceleration and deceleration of the train are frequent,and considerable regenerative braking energy is generated during the braking of the train.Failure to perform reasonable treatment will result in energy waste and severe fluctuations in the DC voltage of the traction network,and even make regenerative braking invalid.Since energy consumption braking will lead to energy waste,not suitable for the concept of energy saving,emission reduction and green development,and the inverter feedback entering the grid may cause harmonic pollution.The braking energy recovery system based on super capacitor storage can recover braking energy during braking and release the energy to the traction network when starting or accelerating.in view of the capacity configuration and high price of super capacitors,this paper proposes a hybrid regenerative braking energy recovery solution for super capacitors and braking resistors.The super capacitor-resistance recovery system can not only effectively solve the above problems,but also recycle the regenerative braking energy generated by the train,ensuring that the DC voltage of the traction network always works within a safe voltage range.First of all,some basic data of trains and vehicles are combined with basic resistance calculation formulas to establish train speed and displacement models to study the braking conditions of trains and vehicles.Analyze the pros and cons of several regenerative braking energy recovery methods,and integrate the current domestic energy storage research status and the trend of traction network voltage changes lasting train braking conditions.,it is determined that the super capacitor-resistance hybrid regenerative braking energy recovery device can make traction The grid voltage works in a safe range.The 24-pulse uncontrollable rectifier unit is used to obtain 1664 V no-load voltage as the traction power supply.The subway locomotive structure is 4 EMUs and 2 trailer mode.The traction motor(PMSM)adopts the space voltage vector control method,A simulation model of the braking condition of the train’s electric drive system is created.Secondly,according to the calculation results of the basic resistance of the subway train and the related constraints of the super capacitor,the super capacitor recovery system is designed and the two-way DC/DC mathematical model of the two-way energy flow control is established.The DC/DC conversion circuit adopts the double closed-loop control idea of traction network voltage as the outer loop and SC charging and discharging current as the inner loop.The SC charging and discharging simulation verifies the correctness of the control method and design requirements.Finally,takeing matlab/simulink simulation to analyze the pros and cons,using resistance energy dissipation or super capacitor energy storage recovery systems alone.Combining all the previous models to construct a subway super capacitor-resistance energy storage system model,the simulation results are compared with the single treatment scheme of braking energy.The comparison of simulation waveforms shows that the hybrid braking energy recovery device stabilizes the traction network voltage within the safe working range,and at the same time improves the energy utilization rate.