Speed control of BLDC motor drive under Direct Torque Control scheme with modified integrator

In this paper, speed control of Brushless DC (BLDC) motor drive under Direct Torque Control scheme with modified integrator for flux estimation is investigated. The initial transient in flux linkage in first switching is reduced by the modified integrator. Here the drive is operated in the constant torque region under the DTC scheme. The speed control operation is achieved using PI controller and sensing the speed. The electrical rotor speed and the back EMF in dq- reference frame is used for the torque estimation. The inverter DC-link voltage and two line currents are measured for control. In DTC, two, two level hysteresis controllers are used for torque and flux control. The validity of the introduced scheme is verified through extensive simulation under MATLAB/Simulink environment. Simulation results indicate good speed regulation of BLDC motor.