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15 results on '"Shawier, Abdullah"'

5. Hysteresis Current Control for Six-Phase Induction Motor Drives With Reduced Ripple and Improved Tracking Based on Subspace Decomposition and Restrained Voltage Vectors

Author

Shawier, Abdullah, Abdel-Azim, Wessam E., Yepes, Alejandro G., Abdel-Khalik, Ayman Samy, Hamad, Mostafa S., Ahmed, Shehab, and Doval-Gandoy, Jesus

Abstract

Six-phase induction motor (6PIM) drives offer enhanced fault tolerance and reduced per-phase ratings. Hysteresis current control (HCC) is attractive for 6PIMs because it is simple, robust and fast. HCC is conventionally implemented so that each leg voltage is directly set based on the respective phase-current error. However, this approach does not consider that, in multiphase drives, phase voltages and currents are related through a combination of equivalent impedances corresponding to various subspaces. In general, there is a notable dissimilarity between these impedances, being typically small for secondary ($\bm {xy}$) subspaces. This can cause large current distortion and poor reference tracking. This article proposes an improved HCC for 6PIM drives. Instead of directly inputting the per-phase current error to the hysteresis comparator and directly applying the switching states chosen by it, the input and output components associated with different subspaces are segregated. The input and output $\bm {xy}$ components are nullified in open loop so that the $\bm {xy}$ impedance no longer affects the HCC behavior, even if low. This prevents the disrupting $\bm {xy}$ currents, ensures effective tracking of the torque/flux-producing $\bm {\alpha \beta }$ reference current, and enables reconfiguration-less fault tolerance. Experiments using 6PIMs with different winding configurations corroborate the significant advantages of the proposal.

Published
2024
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10. Online Control Strategy for Tolerating Resistance Asymmetry With Minimum Copper Loss in the Full Torque Range for Symmetrical Six-Phase AC Drives.

Author

Yepes, Alejandro G., Abdel-Azim, Wessam E., Shawier, Abdullah, Abdel-Majeed, Mahmoud Said, Che, Hang Seng, Abdel-Khalik, Ayman Samy, Ahmed, Shehab, and Doval-Gandoy, Jesus

Abstract

Multiphase drives exhibit remarkable advantages (e.g., fault tolerance) over three-phase ones. Six-phase drives are particularly attractive, given their moderate complexity and suitability for off-the-shelf three-phase converters. Regarding the stator winding arrangement, the symmetrical one offers superior postfault capabilities in most scenarios. On the other hand, resistance asymmetry in the stator phases or connections may arise due to different causes. The conventional full-range minimum-loss strategy (FRMLS) generates stator-current references under open-phase (infinite resistance) faults so that torque ripple is prevented while minimizing the losses for each torque ($\boldsymbol{d}$ - $\boldsymbol{q}$ current) value and maximizing the torque range; however, this method is unsuitable for unequal resistances of finite value. This article proposes an FRMLS for setting the current references to reach these goals in symmetrical six-phase drives with any resistance asymmetry. The optimum references are found online depending on the resistances, without lookup tables. The phase currents are individually limited by an iterative algorithm, so that minimum stator copper loss (SCL) is achieved over the maximum admissible torque range. In this manner, unlike the conventional FRMLS, minimum SCL and maximum torque range are attained even for finite resistance imbalance. The currents in phases affected by high resistances are suitably reduced. Experimental results are provided. [ABSTRACT FROM AUTHOR]

Published
2023
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