Direct torque control of brush less DC motor drive with modified switching algorithm

Abstract

Conventional direct torque control (DTC) of BLDC motor drive is quite cumbersome, because it operates on trapezoidal back EMF. The conventional DTC gives high torque ripple and switching frequency is variable due to bang-bang controllers. In this article, a new direct torque control scheme is proposed to a BLDC motor. This paper focuses to provide better direct torque control mechanism without using co-ordinate transformation and a new modified switching table is proposed with decoupled stator flux linkages. The Proposed DTC is developed based on error produced from torque hysteresis controller and sector information of flux space vector. The sector of flux space vector is obtained by estimating the rotor position of BLDC motor using hall sensors. In this paper, operation of BLDC motor drive in forward and reverse motoring conditions was exhibited. The proposed method is simulated in MATLAB software, Simulation results are provided for forward and reverse motoring and it provides less torque ripple in steady state.