Use this URL to cite or link to this record in EThOS:
Title: Investigation of novel partitioned stator hybrid excited permanent magnet machines
Author: Hua, Hao
ISNI:       0000 0004 6351 9125
Awarding Body: University of Sheffield
Current Institution: University of Sheffield
Date of Award: 2017
Availability of Full Text:
Access from EThOS:
Access from Institution:
Hybrid excited (HE) machines, which combine the high torque density of permanent magnet (PM) machines and the excellent flux controllability of electrical-excited (EE) machines, are of great interest in variable-speed electric drive systems. An additional degree of freedom, i.e. the ratio between the PM and field winding (FW) flux, is obtained. Among a variety of HE machine topologies, the stator-excited configurations employing both PMs and FWs on the stator are attracting increasing attention. This is thanks to the elimination of sliding contacts and complicated structures for three-dimensional (3-D) flux paths. Nevertheless, the statorexcited HE machines suffer from the sacrificed performance due to space conflict, with the stator accommodating PMs, FWs, and armature windings. Partitioned stator (PS) machines were recently proposed to improve the space utilization of conventional stator-PM machines, in which two separate stators are employed to allocate armature windings and PMs respectively, with a salient iron-piece-rotor sandwiched between the two stators. As a result, more space is available for PM and/or copper, with which the torque density and efficiency are both remarkably boosted. In this thesis, based on the analysis on the existing PS machines and the inspiration from diverse rotor topologies in conventional rotorPM synchronous machines, the new PM excitation stator topologies are proposed to extend the family of PS machines. Meanwhile, the ferrite PM is introduced to PS machines to take advantage of the enlarged available space whilst balancing performance and cost. Moreover, the HE concept and the PS configuration can be integrated, providing the benefits of the stator-excited HE machines while relieving the space conflict. With tangentially magnetized PMs, the flexibility of PM and FW locations is identified by allocating the PMs to share the stator with either armature windings or FWs. The comparison between the proposed machines and the corresponding conventional HE machines reveals that the proposed machines can exhibit not only higher torque density, but also better flux controllability. Furthermore, a pair of PS-HE machines with radially magnetized PMs are investigated, based on which the series and parallel connections between the PMs and FWs are obtained respectively. It is found that the series PS-HE machines can exhibit higher torque while the parallel PS-HE machines benefit from better flux controllability. However, it should be noted that the mechanical weakness of the cup-rotor in the PS machines requires further work in the future.
Supervisor: Zhu, Z. Q. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available