Research Of Flux-weakening Control Method For Torque Motors

The traditional lifting structure adopts motor and gear box to drive the roller, so there aremany problems such as the transmission chain too long, efficiency of transmission too low,the structure complicated, dynamic performance not good, high cost and so on. A noveltorque motor can directly drive the roller to lift the heavy weights without the gear box， it’sa very effective method to solve these problems. So the application prospect is very well.However as a result of the crane hoisting mechanism want to achieve the rapid down in orderto improve the efficiency, the torque motor is required to work on higher speed. We hope thatthe torque motor can work exceeds the rated speed through flux-weakening control.This thesis research and discuss the torque motor flux-weakening control in thisbackground. By reading a lot of literatures and information know that the traditional flux-weakening control method relies on the motor parameters and the parameters of motor varieswith the operating condition changed. The motor’s flux-weakening is influenced seriously. Sothe voltage-loop flux-weakening control scheme is presented because this method is notdependent on the motor parameters and easy to realize. And consider the effects of theamplitude limit parameters in dq axis current loop, this article proposes a new method toimprove the current loop. Then, the operating region of flux-weakening speed control for thetorque motors is further extended with the over modulation algorithm of SVPWM. This thesisalso analyzes the motor parameters which influence the performance of flux-weakening andalso put forward some suggestions. In the last the proposed flux-weakening speed-controlsystem of the torque motors is realized by STM32microcontroller, and the effectiveness ofthe system is validated with experiments.