Analysis and performance of a permanent-magnet alternator with disc magnets
Analysis and performance of a permanent-magnet alternator with disc magnets
The development of permanent magnet generators is reviewed and a novel multi-stacked form utilising disc magnets is described. This machine is ideally suited to the production of a high air-gap field from ceramic magnets but polymer-bonded rare-earth magnets may also be used to advantage. A damping device can be incorporated to minimise load angle oscillation. The new form of generator is shown to have a good performance. However, the analysis of its field provides a demanding problem in three-dimensional non-linear field analysis. Two approaches to the solution of the field have been undertaken, one involving a discretisation of the magnetic circuit and obtaining a balance between the driving H field of the magnet, the armature reaction of the stator and the reluctance drops of the discretised flux paths. This method is called 'the discrete reluctance method'. The other approach involves an integral method of field solution applying Green's function. The first method of analysis is described in detail including the computer program developed for performing the numerical solution. The program is designed so as to give the load characteristics of the machine for any load at a given power factor. The use of capacitance to improve regulation and increase output is discussed and this effect is incorporated with the computer program. The ability to predict the performance of the permanent magnet generator provides the basis for optimising its design. The essence of the method of optimisation is that a trial-and-error procedure is followed. A detailed scheme for changing the rotor dimensions is needed and the optimum design is obtained by a search process. The optimisation is carried out by developing a computer program incorporating the load program which is based on a discrete reluctance method. The scope for the application of the new form of generator is given. This is based on the relative advantages of the machine compared with other forms of generator.
University of Southampton
1979
Kurdali, Ahmad
(1979)
Analysis and performance of a permanent-magnet alternator with disc magnets.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The development of permanent magnet generators is reviewed and a novel multi-stacked form utilising disc magnets is described. This machine is ideally suited to the production of a high air-gap field from ceramic magnets but polymer-bonded rare-earth magnets may also be used to advantage. A damping device can be incorporated to minimise load angle oscillation. The new form of generator is shown to have a good performance. However, the analysis of its field provides a demanding problem in three-dimensional non-linear field analysis. Two approaches to the solution of the field have been undertaken, one involving a discretisation of the magnetic circuit and obtaining a balance between the driving H field of the magnet, the armature reaction of the stator and the reluctance drops of the discretised flux paths. This method is called 'the discrete reluctance method'. The other approach involves an integral method of field solution applying Green's function. The first method of analysis is described in detail including the computer program developed for performing the numerical solution. The program is designed so as to give the load characteristics of the machine for any load at a given power factor. The use of capacitance to improve regulation and increase output is discussed and this effect is incorporated with the computer program. The ability to predict the performance of the permanent magnet generator provides the basis for optimising its design. The essence of the method of optimisation is that a trial-and-error procedure is followed. A detailed scheme for changing the rotor dimensions is needed and the optimum design is obtained by a search process. The optimisation is carried out by developing a computer program incorporating the load program which is based on a discrete reluctance method. The scope for the application of the new form of generator is given. This is based on the relative advantages of the machine compared with other forms of generator.
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Published date: 1979
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Local EPrints ID: 462878
URI: http://eprints.soton.ac.uk/id/eprint/462878
PURE UUID: be927565-6a3d-423a-ada6-f7f2d268127a
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Date deposited: 04 Jul 2022 20:19
Last modified: 04 Jul 2022 20:19
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Author:
Ahmad Kurdali
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