Research On Vector Control Of Asynchronous Motor For Rail Transit

In variable-frequency drives of AC motor, the AC motor is a strong-coupling andmulti-variable system in ABC coordinate system, whose mathematical model is toocomplex to be controlled. By the synchronous rotating MT coordinate system，as thispaper presented, the mathematical model can be greatly simplified, the control of thestator current means controlling of flux current and torque current independently, whichis the same as like a DC machine control. About this theory this paper has been presented.Based on the dynamic model of AC motor, the paper presents the control blockdiagram at first, and then explains every component unit, it also introduces the designs ofthe torque current regulator, flux current regulator and the speed regulator in detail. Inaddition, as the key problem of the vector control, define of rotor flux’s orientation isrelevant with the accuracy of the rotor resistor, which varies easily when the motor isoperating. This paper presents a simple and effective strategy to achieve that goal, andalso gives the discussion and simulation.In Matlab/simulink environment, the paper presents the simulation model of vectorcontrol system, the result displays that the motor achieves good steady-state and dynamicperformance. At last, based on experimental bench of DSP chip TMS320F2812,thecontrol algorithm of the simulation model is presented by C Language Programming,motor experiment has been proved that the vector control system of this paper is feasible,which lays the foundation for the further study.