Analysis and control of a brushless D.C. motor drive
Analysis and control of a brushless D.C. motor drive
Brushless dc drives are currently finding widespread application owing to their high performance and low maintenance requirements. However, existing models used in their analysis and control are inappropriate for the prediction of some aspects of dynamics, such as torque ripples. Two models are proposed; the first uses two axis theory and develops an ac type model of the machine; the second uses phase equivalent circuits and a numerical representation of the complete drive system. The first is ideal for permanent magnet synchronous machines, provided that their parameters are accurately known but becomes highly complex when applied to the brushless dc drive. The second has been applied to an all digital brushless dc drive and gives reasonable results although further refinement may be required.
Transfer function for permanent magnet synchronous machines, valid for small excursions about a point, have been developed using the two axis model and are compared with results obtained by experiment. The theory accurately predicts the phase response and the shape but not the magnitude of the gain response, for which the theoretical results are overdamped. Torque ripple can be substantial in brushless dc drives but measures to reduce it tend to compromise dynamic response. Two methods are examined: a novel excitation scheme which reduces torque ripple with only a small
reduction in dynamic performance, and the introduction of acceleration limits which achieves large reductions in ripple with a large effect on dynamic performance. However further development of these methods into a dual mode controller which sets acceleration limits according to operating conditions reduces torque ripple to levels which could not be measured using the equipment available.
University of Southampton
Harrison, Simon Charles Andrew
1990
Harrison, Simon Charles Andrew
Harrison, Simon Charles Andrew
(1990)
Analysis and control of a brushless D.C. motor drive.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Brushless dc drives are currently finding widespread application owing to their high performance and low maintenance requirements. However, existing models used in their analysis and control are inappropriate for the prediction of some aspects of dynamics, such as torque ripples. Two models are proposed; the first uses two axis theory and develops an ac type model of the machine; the second uses phase equivalent circuits and a numerical representation of the complete drive system. The first is ideal for permanent magnet synchronous machines, provided that their parameters are accurately known but becomes highly complex when applied to the brushless dc drive. The second has been applied to an all digital brushless dc drive and gives reasonable results although further refinement may be required.
Transfer function for permanent magnet synchronous machines, valid for small excursions about a point, have been developed using the two axis model and are compared with results obtained by experiment. The theory accurately predicts the phase response and the shape but not the magnitude of the gain response, for which the theoretical results are overdamped. Torque ripple can be substantial in brushless dc drives but measures to reduce it tend to compromise dynamic response. Two methods are examined: a novel excitation scheme which reduces torque ripple with only a small
reduction in dynamic performance, and the introduction of acceleration limits which achieves large reductions in ripple with a large effect on dynamic performance. However further development of these methods into a dual mode controller which sets acceleration limits according to operating conditions reduces torque ripple to levels which could not be measured using the equipment available.
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Published date: 1990
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Local EPrints ID: 458297
URI: http://eprints.soton.ac.uk/id/eprint/458297
PURE UUID: 9c504372-25fc-4029-b95b-c483bb42ab03
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Date deposited: 04 Jul 2022 16:46
Last modified: 04 Jul 2022 16:46
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Author:
Simon Charles Andrew Harrison
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