Abstract:

A direct torque control (DTC) method based on Space Vector Pulse Width Modulation (SVPWM) algorithm was investigated by simulation based on Matlab/Simulink and experiment based on DSP28335 motor control system to solve the problems of the torque and flux ripples and current distortion of traditional DTC for
Permanent Magnet Synchronous Motor (PMSM). The working conditions were of loading torque 20 Nm after starting to 1 500 r/min and stepping torque to 60 Nm and 40 Nm while the speed was stable at 1 500 r/min. The motor runs stably and the noise reduced obviously during the whole experiment process. The results show that the DTC based on SVPWM improves the system control performance by reducing the torque ripples 5.6% and 14% respectively and achieves the circle flux waveform effectively comparing with traditional direct torque control. Therefore, using the proposed method can solve the problem that the traditional DTC only can select one basic voltage vector to control in each control cycle.

Key words: permanent magnet synchronous motor (PMSM), direct torque control (DTC), space vector pulse width modulation (SVPWM), torque ripple, current harmonic