Novel prediction technique for direct torque control of induction motor

A novel prediction technique for the direct torque control (DTC) of an induction motor is presented in the paper. The conventional DTC method selects voltage vectors from switching table. The application of these vectors does not satisfy demands for torque increase or decrease at all operating conditions and is not optimal regarding torque ripple. The novel prediction technique calculates in every sampling period the torque changes for different voltage vectors and selects discrete voltage vector which results in minimum torque deviation from the reference value. The voltage vector is selected from new switching table and applied for the whole sampling period. In comparison with the conventional DTC method, the novel technique considerable reduces torque ripple in medium and high speed region. Simulation and experimental results for 525kW motor are presented to validate the proposed technique.