Modified Direct Torque Control for BLDC Motor Drives

Abstract

In this paper, a new adaptive reference based approach to direct torque control (DTC) method has been proposed for brushless direct current (BLDC) motor drives. Conventional DTC method uses two main reference parameters as: flux and torque. A main difference from the conventional method of it was that only one reference parameter (speed) was used to control the BLDC motor and the second control parameter (flux) was obtained from speed error through the proposed control algorithm. Thus, the DTC performance has been especially improved on systems which need variable speed and torque during operation, like electric vehicles. The dynamic models of the BLDC and the DTC method have been created on Matlab/Simulink. The proposed method has been confirmed and verified by the dynamic simulations on different working conditions. The simulation studies showed that the proposed method reduced remarkably the speed and the torque ripples when compared the conventional DTC method. Moreover, the proposed method has also very simple structure to apply the conventional DTC and its extra computational load to the controller is almost zero.