Research On Subway Traction And Regenerative Braking Energy Feedback Control System

Urban rail transit,especially subway,is a way to solve the problem of traffic congestion,environmental pollution and energy waste,etc.Currently,asynchronous traction motor is mostly used to subway and motor volume and energy conservation is restricted.Due to shorter distance between stations,train frequent start-stop and brake,braking energy is consumed as heat.To solve the above problem,the control scheme of permanent magnet motor traction drive and regenerative braking energy in subway system is presented and the whole process of energy absorption under the traction drive is studied.The permanent magnet traction motor vector control without speed sensor is used in traction drive of the subway regarded24-pulse rectifier traction grid as DC power supply.By using a sliding mode observer to measure motor's speed etc.,the sensor installation and maintenance are omitted.In the same condition,In the aspect of energy saving,the permanent magnet motor is about 1.15 times of the asynchronous motor.After comparing the advantages and disadvantages of several regenerative braking methods for braking energy of train brake,superior inverter feedback is regarded as the good method of the baking energy absorption and utilization.And the parameters of LCL filter,isolation transformer and the others in the inverter feedback device are designed.Finally,the overall model of subway traction drive and regenerative braking energy feedback inverter control is established.By MTLAB/Simulink simulation software,the subway system of the traction drive and regenerative braking energy inverter feedback control is simulated in the process of traction,coasting and braking.The simulation results show the feasibility of the regenerative braking energy recovery and the improvement of the traction network voltage.In addition,the system is simulated for the different train speed and the different number of trains.In the case of excess braking energy,the way ofintegrated regenerative braking energy,not only solve the rising of the traction grid voltage,but also can effectively recover the energy and the desired result is achieved.