Increasing Output Torque by Means of Space Vector Current Regulation in an Open-End Winding AC Electrical Machine

The maximum torque of the traction drive is usually restricted by the current limit of the power converter. While the maximum current is produced by one of the phases of a star-connected electrical machine, two other phases conduct only half of their current capability. An open-end winding motor configuration allows to increase these currents independently in order to obtain higher output torque of the motor. The proposed current control strategy for open-end winding machine utilizes the similar approach with the space vector pulse-width modulation. The zero-sequence current is injected, which does not produce torque, but is used for the peak shaving of the first harmonic current component. The proposed space vector current regulation was examined using simulation model and showed the possibility to increase the output torque of the drive by 15% without increasing the magnitudes of the stator currents. And vice versa, the peak current can be decreased by 15%, and the maximum junction temperature can be decreased by 17.5% together with lower temperature deviation of the junction over electrical revolution.