Direct torque controlled induction motor drive using modified five-level torque controller for reduction in torque ripple

The work presents a modified switching strategy in a five-level torque controller while implementing a direct torque control scheme for the induction motor (IM) drive. Apart from the presence of conventional full-voltage vectors, the inclusion of intermediate- and zero-voltage vectors brings in the modification above in a five-level torque controller. Moreover, the estimation of flux in the scheme is done by machine current model. These adjustments result in the reduction in the torque and speed ripples; and improve the flux regulation in the low-speed region, thereby obtaining superior low-speed performance. The performance of the proposed scheme is exhaustively tested in MATLAB/Simulink and further by hardware experimentation with a laboratory-type setup of 2.2 kW, two-level voltage source inverter fed IM drive.