Research On Full Speed Range Control Strategy Of Tracion Motor For Rail Transit

In variable-frequency drives of AC motor, the control of locomotive traction motorplays a very important role on the running of electrical locomotive. By using the coordinatetransformation, the mathematical model of asynchronous motor can be simplified, so wecan control the flux current and torque current independently, as this paper presented. Basedon the development of high power electrical locomotive, the vector control technology andsome related problems are studied.The paper presents the fundamental of the vector control and the control block diagramby the research on the control strategy of electrical locomotive. Because the incorrect rotortime constant or the incorrect rotor resistor influences the rotor flux’s orientation and theperformance of vector control. The strategy of field orientation based on q-axis rotor flux isproposed. Simulation proves the validity of the strategyThe space vector pulse width modulation and over-modulation algorithm are proposedbased on the development of high speed electrical locomotive and the application of lowvoltage for the traction converts. the multi-mode pulse width modulation is used based onthe different speed of electrical locomotive. This paper presents a new vector control for theelectrical locomotive in a One-Pulse PWM model of inverters and changes the rotor flux toguarantee the dynamic performance in the high speed. Because the amplitude of voltagevector is restricted constant in this mode, the conventional vector control isn’t applied.In the Matlab/Simulink environment, the paper presents the simulation model of vectorcontrol system. The experimental results based on experimental bench of DSP chipTMS320F2812prove that the control of this paper is feasible. The vector control strategywithin the whole speed range for the electrical locomotive is proposed at last.