Position sensorless direct torque control of brushless DC motor based on back-EMF vector

摘要

Direct torque control (DTC) can directly control the inverter states in order to reduce the torque and flux linkage errors within the prefixed band limits. The amplitude of the stator flux linkage cannot be controlled in commutation region with two-phase conduction mode. In this paper, using the back-EMF (or rotor flux) vector angular phase in α-β αx is stationary reference frame and active and reactive torque errors with their commands, the proper switching pattern can be selected to control the generated torque and reducing commutation torque ripple. As well as, the stator phase current waveform is obtained quasi-square wave therefore has fast dynamic response for torque control. Simulation and experimental results confirm that the proposed method reduces torque ripple in comparison with previous research works.