Most electrical machines available in the market utilise some form of silicon iron (SI) as the core material. Although SI based electrical machine manufacturing methods are well established and simple, SI has significant iron losses specifically in high frequency variable-speed motor drive applications. Two alternative magnetic materials have recently been developed: amorphous magnetic material (AMM) and soft magnetic composite, which can each offer unique characteristics that can be utilised to improve the performance of electric machines. AMM offers extremely low iron losses which makes it a good candidate for high-efficiency and variable-speed motor applications. However, due to handling and cutting limitations, AMM has not been utilised widely in rotating electrical machines. A commercially viable AMM cutting technique was recently developed by the industrial partner of this project. It is thus now practical to cut the AMM ribbon into a machine stator, particularly for axial-field stators which generally require less cutting than radial-field stators. This thesis investigates an innovative motor design based on applying the cut AMM in an axial-field permanent magnet (AFPM) machine for general drive applications. It includes a detailed review of the analytical approach, finite element analysis (FEA), iron loss investigation and prototype performance comparisons. Analytical analysis of the AFPM machine was performed and the key design variables were evaluated to optimise the design parameters based on the use of AMM. The AMM cutting constraints, design and performances trade-offs were also investigated in the design. The research study provides a design procedure to determine the basic physical size and configuration (e.g. combination of the number of slots and poles, slot width and depth, number of winding layers, air gap length, magnet thickness) based on certain basic specifications. In addition, a comprehensive investigation was conducted on the iron loss of various materials to compare these with AMM. Due to the three dimensional (3D) nature of the AFPM structure, the theoretical design was validated using 3D FEA and extensive simulation results are provided. A number of AMM AFPM prototypes were successfully designed and constructed. Due to limited available materials, the prototypes were built using uncoatedAMMribbon which has substantially higher iron loss characteristics. Nevertheless, it is believed that it would still provide a valuable understanding of the real machine characteristics and allow initial design validation. The prototype was tested in a custom-built test rig to validate the analytical and 3D FEA predictions. Overall, a good correspondence between the results and predictions has been achieved. Extensive experiments have been conducted to investigate and demonstrate the characteristics of the AMM prototype machines which are based on fractional-slot concentratedwinding single-sided AFPM machines. This includes comparisons against identical silicon iron and soft magnetic composite prototypes. In addition, the laboratory experimental results also highlighted the significant effect of the open-circuit losses on the overall machine performance. Therefore, the open-circuit loss components which includes bearing, windage, magnet and iron losses were separated based on 3D FEA and experimental results. The above research studies demonstrated the potential and feasibility of cut AMM to produce highly efficient AFPM machines. In addition, the innovative cutting technique also has the potential for mass production of low-cost AMM machines. The research work in this thesis makes a significant contribution to the design of axial-field permanent magnet machines based on AMM. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1375647 / Thesis (Ph.D.) -- University of Adelaide, School of Electrical and Electronic Engineering, 2009
| Identifer | oai:union.ndltd.org:ADTP/288071 |
| Date | January 2009 |
| Creators | Liew, Gene Shane |
| Source Sets | Australiasian Digital Theses Program |
| Detected Language | English |
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