Study On Control And Electromagnetic Performance Of Linear Traction Motor

At the present day, urban traffic is becoming worse increasingly. Development of urban wheel-on-rail transportation systems is urgent to solve the urban traffic problems. The linear motor is a new driving type of urban rail transit system and the research on linear motors has become the focus currently. Nowadays, the linear metro system is driven by linear induction motor (LIM). So, it is very necessary to do research on LIM.In the light of the project research on linear induction motors and driving system consigned by Guangzhou Metro Company, the steady-state characteristics of LIM are analyzed; the control method is studied; the magnetic field distribution is simulated; Electro Magnetic Interference (EMI) experiment is made.Based on the analysis of the different structure between linear induction motor and rotary induction motor (RIM), referring to the research method of RIM, we get a complete equivalent circuit, considering end effects of LIM, and calculate the steady-state characteristic of LIM. We also contrasted the result of experiment with the result of calculation. In this thesis, an approach to vector control for a LIM considering end effects was proposed. An equivalent circuit model in rotor flux oriented frame is developed for the vector control of a LIM by adding the end effects to the RIM model. The vector control system is created and the result of simulation is satisfying. We also have demonstrated through experiments the good response characteristic by the proposed scheme. For getting magnetic field distribution in air gap, this thesis adopted the software Ansoft to analyze a LIM model, using finite element method. The magnetic distribution in air gap is obtained and discussed. For the special structure of LIM in urban traffic, the problem of EMI must be considered. We have made the experiment of LIM of EMI and proposed an EMI measure scheme.