Modeling And Simulation Research Of Permanent Traction System For Urban Rail Transit

The core module of the urban rail transit train is the traction system,which is an important component to drive the train and implement the energy conversion and transmission.As the permanent magnet synchronous motor takes the advantage of high efficiency,smooth speed,strong overload capacity and high power factor as well as other benefits,permanent magnet synchronous motor as a new generation of traction motors will soon be used in urban rail transit trains,and a very broad vision.In this thesis,the traction system of urban rail transit EMU with the usage of permanent magnet synchronous motor is discussed.The control and simulation of the control of permanent magnet synchronous motor and the traction dynamics of urban rail transit EMU related are carried out.Based on the permanent magnet synchronous motor(PMSM)and the vector control technology commonly used in engineering practice,a vector control system based on extended Kalman filter and a vector control system based on rotating high frequency component injection method are established for simulation of velocity estimation.In this thesis,the steady-state working characteristics of permanent magnet synchronous motor are described in detail.On the basis of it,the maximum torque-current ratio and the weak-field control strategy are briefly used in the vector control system.Finally,the permanent magnet synchronous motor control strategy and urban rail transit EMU operating conditions to match and combine,in MATLAB to build an urban rail transit permanent magnet traction system simulation model,realize traction process simulation.In this thesis,the speedless sensor control method,which is often used when driving permanent magnet synchronous motor,is described and analyzed in detail.In the control process,the observer is used to observe the stator flux extension of permanent magnet synchronous motor.And then realize the precise closed-loop control of the torque control system in the vector control system.Aiming at the different speed stages of the train operation,an hybrid speed sensorless control scheme is proposed,and the control scheme.The simulation results show that the scheme can estimate the speed of the motor and the position of the rotor in the full speed domain of the train.The estimation scheme of the torque and speed will provide the urban rail transit permanent magnet traction system with an important foundation for the implementation.