Browsing by Author "Wang, Can-Fei"

Now showing 1 - 4 of 4
  • Thumbnail Image
    ItemOpen Access
    Cogging torque suppression in a permanent-magnet flux-switching integrated-starter-generator
    (2010-09-13T00:00:00Z) Jin, Meng-Jia; Wang, Y.; Shen, Jian-Xin; Luk, Patrick Chi-Kwong; Fei, Wei-Zhong; Wang, Can-Fei
    Permanent-magnet flux-switching (PMFS) machine offers high torque density, impressive flux-weakening capability and mechanical ruggedness because of its distinctive configuration, and is potentially suitable for the application in automotive integrated-starter-generators (ISGs). However, the PMFS machine generally exhibits higher cogging torque compared with other machines commonly used in ISGs. Minimisation of the cogging torque in the PMFS machine for its utility in ISGs is therefore of particular importance. Four rotor topologies are proposed here as cost-effective means to suppress the cogging torque of a PMFS ISG. The validity of the proposed techniques has been confirmed by both two- dimensional finite-element analysis and experimental results. Moreover, the influence on the back electromagnetic force by these techniques is also investigated.
  • Thumbnail Image
    ItemOpen Access
    Design and analysis of a new outer-rotor permanent-magnet flux-switching machine for electric vehicle propulsion
    (2011-01-31T00:00:00Z) Fei, Wei-Zhong; Shen, Jian-Xin; Wang, Can-Fei; Luk, Patrick Chi-Kwong
    Purpose − The purpose of this paper is to propose a new outer-rotor permanent- magnet flux-switching machine for in-wheel electric vehicle propulsion. The paper documents both the design procedure and performance investigation of this novel machine. Design/methodology/approach − The topology and preliminary sizing equations of the outer-rotor permanent-magnet flux-switching machine are introduced. Both the number and width of rotor poles are then optimized using comprehensive two-dimensional FEA. The machine losses are particularly investigated by transient FEA for the optimal design. Findings − A outer-rotor permanent-magnet flux-switching machine, with 12 stator poles and 22 rotor poles, is most suitable for the proposed application. The analytical sizing equations are quite efficient with a suitable level of accuracy for preliminary design. The optimal rotor pole width from the FEA results is nearly 1.3 times of the original one. The efficiency of the proposed machine under rated load is relatively low, nearly 85%, as a result of significant eddy current losses in the permanent magnets, which can be effectively suppressed by implementing segmentation. The predicted outstanding performance implies that by adopting magnet segmentation the proposed machine is a leading contender for direct electric vehicle drives. Research limitations/implications − The end effects, which could be considerable in the machine with relatively short axial length, are neglected during the study. In addition, due to the high current density and deep slot, proximity losses in the winding which is not issued in this research could be significant. All the limitations mentioned above could bring corresponding errors to the results. Although the research is concentrated on the application of electric vehicle drive, the techniques can be potentially employed for other applications. Practical implications − The practical implementation of such a machine is confronted with several mechanical hurdles, especially the thermal issues which can be addressed by implementing innovative cooling system. Originality/value − The outer-rotor permanent-magnet flux- switching machines so far have not been addressed yet. This research provides designers with the technical background and another alternative for electric vehicle
  • Thumbnail Image
    ItemOpen Access
    Design issues of an IPM motor for EPS
    (Emerald Group Publishing Limited, 2011-12-31T00:00:00Z) Wang, Can-Fei; Shen, Jian-Xin; Luk, Patrick Chi-Kwong; Fei, Wei-Zhong; Jin, Meng-Jia
    In electric power steering (EPS), permanent magnet (PM) brushless ac (BLAC) motors offer distinct advantages over other electric motor types in terms torque smoothness, reliability and efficiency. The design procedure of an interior permanent magnet (IPM) motor used in EPS is presented in this paper. The requirements of the steering system are first introduced, and the machine's specifications are then derived. Critical issues which have considerable impacts on the machine's performance, such as operation mode, rotor structure and slot/ pole combination, are analyzed. Subsequently, a 12-slot/10-pole sinusoidally excited IPM machine with concentrated windings is proposed and optimized based on finite element analysis (FEA) modelling. The losses and efficiency are then computed. Performance predictions from the FEA results confirm all the requirements are met or exceeded. A prototype motor has been built for validation.
  • Thumbnail Image
    ItemOpen Access
    Development of a magnetic-geared permanent-magnet brushless motor
    (IEEE, 2009-09-22T00:00:00Z) Wang, L. L.; Shen, Jian-Xin; Luk, Patrick Chi-Kwong; Fei, Wei-Zhong; Wang, Can-Fei; Hao, He
    High-torque and low-speed electrical drives are often employed for applications where mechanical gearing cannot be accommodated. On the other hand, permanent-magnet (PM) gear has drawn significant attention from both academies and industries due to the conspicuous merits, such as reduced acoustic noise, maintenance free, improved reliability, precise peak torque transmission capability, and inherent overload protection. In this paper, a magnetic-geared PM brushless motor is presented. It is a novel low-speed and high-torque motor which merges the advantages of conventional PM brushless motor and PM gear. Its topology and operation principle are introduced. Some techniques are employed to optimize and improve the motor performance, while the validity of the proposed techniques is verified with finite-element analysis. Moreover, an alternative operation condition, which can further reduce the motor speed and increase its output torque, is proposed and analyzed.