Direct Torque Control Algorithm with Synthetic Voltage Vectors for Symmetrical Six-Phase Induction Motor

This paper presents the synthetic voltage vector (VV) based direct torque control (DTC) algorithm for the six-phase symmetrical induction motor which is fed by six-leg two-level voltage source inverter (VSI). In DTC, levels of torque controller decide the content of torque ripples. Mostly, five-level torque comparators are preferred over the three-level torque comparators to improve the torque ripple content. When five-level torque comparator is used, small voltage vectors of dq-subspace are mapped in the xy-subspace. This subspace is not responsible for the torque production. It is proposed to form synthetic voltage vectors in order to reduce the xy-subspace flux. The developed algorithm is verified by the simulation and experimental results.