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 ( dd - qq current) value and maximizing the torque range; however, this method is unsuitable for unequal resistances of finite value. This paper 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 look-up 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.
Bibliographical noteKAUST Repository Item: Exported on 2022-09-09
Acknowledgements: This work was supported in part by the Malaysian Ministry of Higher Education (MOHE) through Fundamental Research Grant Scheme FP090- 2020, in part by Science. Technology & Innovation Funding Authority (STDF) under grant (37066), 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.
ASJC Scopus subject areas
- Electrical and Electronic Engineering