Direct torque control of three-level five-phase inverter-fed five-phase induction motor with common-mode voltage elimination

In this paper, the common-mode voltage (CMV) elimination is focused on five-phase induction motor (F-PIM) drive which is controlled by a direct torque control method. Since the motor is fed by inverter, the CMV is generated in the drive. The CMV allows common-mode current (CMC) to circulate in the bearing parts of the drive. The CMC may eventually damage the complete drive, if it is not controlled. Therefore, the proposed DTC strategy targets the elimination of the CMV. Since the F-PIM is fed by three-level five-phase inverter (T-LF-PI), there are 243 voltage vectors (VVs) available for the DTC operation. These VVs are distributed at different locations in d-q stator plane in the form of main and intermediate VVs. The 41 intermediate VVs are selected, due to their ability of eliminating the CMV, through seven-level torque and two-level flux comparators. By implementing a seven-level torque comparator (S-LTC) the torque ripple is reduced. For validating the proposed DTC method, simulation and experimental results are provided.