Date of Award


Publication Type


Degree Name



Electrical and Computer Engineering





Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.


The electric drive system of a permanent magnet synchronous machine (PMSM) with stator winding impedance asymmetry draws unbalanced three-phase stator currents if the conventional current control scheme is employed. Due to these asymmetrical stator currents, some issues such as uneven heating of the inverter phases and switches, additional losses in the motor due to skin and proximity effects, vibration and noise, uneven heating of the motor phases, and torque ripple appear in the PMSM drive. These effects reduce the reliability, efficiency, and lifespan of the machine. The conventional proportional-integral (PI) current controller in a PMSM drive is unable to mitigate the imbalanced stator current and torque ripple in the PMSM with asymmetric phases due to its incapability to deal with the unbalanced sinusoidal input stator currents. To address this limitation, this thesis presents a PI resonant (PIR) current controller, which comprises of a PI controller in conjunction with the resonant controller and harmonic compensation terms in the inner current control loop of an interior PMSM (IPMSM) drive with stator winding impedance asymmetry. The harmonic-based resonant controller part of the PIR controller is used to compensate the harmonics of the stator current. A significant reduction in the asymmetrical stator currents of the machine using the proposed PIR current controller compared to a conventional PI current controller is demonstrated for a 100-kW traction IPMSM with phase asymmetry. It has been found that the torque ripple in the machine is significantly minimized.