Research On AC Variable-frequency Speed Adjusting System Based On DSP

AC variable frequency (v/f) speed-adjusting system of asynchronous motor with speed-current double closed-loop is researched and software and hardware systems are designed in this paper. This system adopts SVPWM (Space Voltage Pulse Width Modulation) control technology and FOC (Field Oriented Control) control algorithm based on TMS320LF2407A DSP which is special chip of TI for motor control. It introduces the general method of SVPWM technology, presents control strategies of v/f speed-adjusting system and builds mathematics models of all control modules. With the MATLAB/SIMULINK simulation models of asynchronous motor, SVPWM and v/f system etc. with its module library and S-function are established. According to the vector control algorithm and experiment parameters, the simulation models are tested and corrected in time until the models are optimized. The result of simulation shows the high performance and the good precision. Using IMCD2407 DSP Emulation board,one v/f adjustable-speed hardware system is developed including motor, photoelectric encoder and the driver board. With assembly or C language of DSP some control programs of the v/f adjusting-speed system are designed including mainly SVPWM, RFOC and the detection of current and speed.