Improved Direct Torque Control Scheme based on Modified Torque Hysteresis Band

摘要

In this paper a very simple modified Direct torque control (DTC) scheme based on hysteresis band control is proposed for induction motor drive. DTC is widely used scheme for variable frequency drive due to its simple control structure and effective performance compared to other controlling schemes. But steep flux and torque ripples and poor flux regulation are some major flaws of classical DTC. A significant curtail in ripples of torque and flux, improvement in flux regulation, and finer performance of drive at low motor’s speed are examined by the proposed modified DTC by not compromising with its most important feature of simple structure. In modified DTC by simply monitoring the flux error range the hysteresis torque band can be accordingly varied dynamically. Comparisons of both the schemes for different parameters variations and the effectiveness of the proposed DTC performances are validated by the Matlab/Simulink results.