DTC of three-switch three-phase inverter fed induction motor drives

The paper proposes two novel direct torque control (DTC) strategies dedicated to three-switch three-phase inverter (TSTPI) fed induction motor (IM) drives. The TSTPI generates six asymmetric active voltage vectors in the stationary plane: (i) three high-amplitude vectors and (ii) three low-amplitude vectors. Suitable combinations of the three high-amplitude voltage vectors are considered in the vector selection table of the first DTC strategy. While, the second one considers the subdivision of the stationary plane into six sectors. This approach is similar to the one adopted in the Takahashi DTC strategy dedicated to IM drives fed by the conventional six-switch three-phase inverter (SSTPI). A simulation-based comparison between both DTC strategies has highlighted the superiority of the second DTC strategy especially with respect to the motor current distortion.