Open-Phase-Tolerant Online Current References for Maximum Torque Range and Minimum Loss With Current and Torque-Ripple Limits for n-phase Nonsalient PMSMs With Nonsinusoidal Back-EMF

Abstract
Multiphase permanent-magnet synchronous machines (PMSMs) with nonsinusoidal back-electromotive force (back-EMF) offer high fault tolerance and torque density for electric vehicles. Most current-reference generation methods either minimize stator copper loss (SCL) or maximize achievable torque. Optimization of both goals is accomplished by full-torque-range minimum-loss (FRML) strategies, but so far just for sinusoidal back-EMF. Thus, FRML for nonsinusoidal back-EMF should be sought. Moreover, many methods are only suitable for healthy conditions or specific machines, harmonics, or open-phase-fault (OPF) scenarios. Additionally, the torque range may be extended by permitting torque ripple or (transiently) greater rms current, but this approach is not general nor FRML yet. This paper proposes online FRML current-reference generation for multiphase PMSMs with nonsinusoidal back-EMF: nonsinusoidal-back-EMF FRML (NSBE-FRML). When the torque reference is feasible, minimum SCL is attained while maximizing the achievable torque (i.e., FRML). For higher torque references, the instantaneous torque deviation is minimized, and the torque reference is saturated in consecutive samples limiting the torque ripple to a pre-specified threshold. Furthermore, the rms current is limited after transient overload by automatically decreasing the torque reference. The NSBE-FRML is suitable for any harmonics, healthy/OPF conditions, and multiphase PMSMs with negligible saliency ratio. Experiments are performed with a six-phase PMSM.

Citation
Yepes, A. G., Abdel-Azim, W. E., Shawier, A., Abdel-Khalik, A. S., Hamad, M. S., Ahmed, S., & Doval-Gandoy, J. (2023). Open-Phase-Tolerant Online Current References for Maximum Torque Range and Minimum Loss With Current and Torque-Ripple Limits for n-phase Nonsalient PMSMs With Nonsinusoidal Back-EMF. IEEE Transactions on Transportation Electrification, 1–1. https://doi.org/10.1109/tte.2023.3288525

Acknowledgements
This work was supported in part by ITIDAs ITAC collaborative funded project under the category type of advanced research projects (ARP) and grant number ARP2020.R29.7, in part by the Government of Galicia under the grants ED431F 2020/07 and GPC-ED431B 2020/03, in part by the Ministry of Science, Innovation and Universities under the Ramon y Cajal grant RYC2018-024407-I, and in part by the Spanish State Research Agency (AEI) under project PID2019-105612RB-I00/AEI/10.13039/501100011033.

Publisher
Institute of Electrical and Electronics Engineers (IEEE)

Journal
IEEE Transactions on Transportation Electrification

DOI
10.1109/tte.2023.3288525

Additional Links
https://ieeexplore.ieee.org/document/10159366/

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