Direct Torque Control of BLDC Drives With Reduced Torque Pulsations

This paper illustrates the direct torque control strategy for a non-salient pole brushless DC motor (BLDC) having non-sinusoidal back emf (EMF). In the literature, a few strategies have been put forth for BLDC motor drives to acquire ideal current as well as torque control with minimal torque ripple. Majority of the strategies are confounded and high speed operation with them is not feasible because stator flux linkage control has not been considered. In this paper, a uncomplicated and effective approach is portrayed to obtain ripple free torque at low frequency and maximum efficiency. The proposed technology intently takes after the previously used DTC approach used for sinusoidal AC motors to such an extent that it controls the torque under direct control scheme and flux amplitude of the stator under indirect scheme. Moreover, to reduce the low frequency torque pulsations, electrical rotor position is determined separately and then transmuted into dq-reference frame equivalents with the help of park transformations. Then torque can be estimated by setting them up in the look-up table. Simulation results validate the superiority of DTC scheme over other conventional schemes as it results in decreased torque ripple and hence gives better and faster dynamic response.