Overview of permanent-magnet fault-tolerant machines: Topology and design

Abstract

Permanent-magnet (PM) machines have attracted a lot of interest in various applications since they have the merits of high torque density, high power density and high efficiency. However, issue of poor fault tolerance of the conventional PM machines restricts their practical applications in the field of safety-critical applications, e.g. aerospace, electric vehicle, electrical propulsion and wind power generator applications. An enormous amount of work has been done to improve the faulttolerant capability of PM machines. This paper will review research work on PM fault-tolerant machines up-to-date, including modular design, short-circuit current limitation design, redundant design, ease of thermal dissipation of PM design, and torque enhancement design techniques. The work of this paper can provide some references for future studies and engineering applications of PM fault-tolerant machines for safety-critical applications.

Comparative Research on Four-Phase Dual Armature-Winding Wound-Field Doubly Salient Generator With Distributed Field Magnetomotive Forces for High-Reliability Application

“…Further, since WFDSMs is widely used in some high-reliability area, the fault-tolerant capability is also considered during investigating stator/rotor pole combination. In generally, the significant requirements for improving fault-tolerant capability should be considered as follows [22]: 1) electrical/magnetic isolation between phases; 2) phase number; 3) effective thermal isolation between phases; 4) physical isolation between phases; 5) implicit limiting of short-circuit current. Thus, the short-circuit current is reduced by increasing the self-inductance under short-circuit fault and the magnetic coupling effect can be suppressed by decreasing the mutual-inductance between phases, which are significant to improve fault-tolerant capability.…”

“…For four-phase machine, the stronger fault-tolerant capability can be obtained compared to the three-phase one, and the higher power density can be obtained compared to the five-phase one. Thus, the choice of fourphase one will be considered as a compromise between fault-tolerant capability and power density [22]. Furthermore, in order to obtain the better fault-tolerant capability, the influence of stator/rotor pole combination on the fault-tolerant capability is also investigated.…”

Investigation of influence of winding structure on reliability of permanent magnet machines

“…The gap between them increases with the decrease of λ pps and λ wo , especially λ wo . The partial differential of MTTF equations of DDW, DSW, CDW, and CSW structures are performed for λ wo and λ pps respectively by equation (18).…”

“…The fault-tolerant control of nine-phase and twelve-phase FSPM machine under fault was investigated in [15]- [17]. The topology and design of PM fault-tolerant machines were summarized in [18].…”

Rotor magnet demagnetisation diagnosis in asymmetrical six‐phase surface‐mounted AC PMSM drives

“…Multiphase permanent-magnets synchronous machines (PMSMs) have gained an impressive interest during the last decade as a potential alternative to their three-phase PM machine counterparts, for safety-critical variable-speed drive applications as well as highpower energy conversion systems [1]. The main motivation of this interest is to combine the merit of high-torque/power switch rating of the PM machines [2], with additional degrees of freedom, which are increasing with the number of phases, leading to a significant increase of efficiency and fault tolerability of the machine [3][4][5]. These advantages are of paramount importance for modern wind energy conversion systems [6], aerospace, or 'more electric aircraft' concept [7], where high-reliability standards are required.…”