Online control strategy for tolerating resistance asymmetry with minimum copper loss in the full torque range for symmetrical six-phase AC drives
Document Type
Article
Publication Date
1-1-2023
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 (d-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.
Keywords
Fault tolerance, High-resistance connections, Multiphase drives, Resistance asymmetry, Six-phase machine, Variable speed drives
Divisions
umpedac
Funders
Malaysian Ministry of Higher Education (MOHE) through Fundamental Research Grant Scheme (Grant No: FP090-2020),Science and Technology Development Fund (STDF) (Grant No: 37066),Government of Galicia (Grant No: ED431F 2020/07 & GPC-ED431B 2020/03),Innovation and Universities under the Ramon y Cajal (Grant No: RYC2018-024407-I),Spanish Government (Grant No: PID2019-I05612RB-I00/AEI/10.13039/501100011033)
Publication Title
IEEE Transactions on Power Electronics
Volume
38
Issue
1
Publisher
Institute of Electrical and Electronics Engineers
Publisher Location
445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA