Torque ripple minimization & closed loop speed control of BLDC motor with hysteresis current controller

In Brushless DC (BLDC) motor ripple-free torque can be produced by preshaping the excitation currents with the help of electronically controlled commutators. This ripple-free torque minimizes copperlosses. In this paper, the position-sensorless direct torque and indirect flux control of brushless dc (BLDC) motor with non sinusoidal back electromotive force (EMF) has been extensively proposed. In the literature, several methods have been proposed for BLDC motor drives to obtain optimum current and to obtain optimum current and torque control pulsations in BLDC motor drives. Most methods are complicated and do not consider the stator flux linkage control, therefore, possible high-speed operations are not feasible. In this study, a novel and simple approach to achieve a low-frequency torque ripple-free direct control with maximum efficiency is presented. This method does not require pulse width modulation and need proportional plus integral regulator with respective hysteresis current controlling technique and also permits the regulation of varying signals. The validity and practical applications of the proposed sensorless three-phase BLDC motor drive scheme are verified through simulations results using Matlab/Simulink Platform.