High Power Density, High Speed, Three Phase Brushless Permanent Magnet DC Motor

This thesis describes a development of a high power density, high-speed 3-phase permanent magnet brushless dc motor developed specifically for use in aircraft and defence applications. The drive is essentially intended for low power, high-speed application and it incorporates an
integral electronic controller. Special attention is paid to the geometry of the rotor assembly.
The development of high power density permanent magnet machines has had several unsuccessful attempts by distinguished researchers. These past attempts made use of the concept of flux focusing technique which provides the airgap flux density that is higher than that in the magnets. The original contribution of the thesis is a novel rotor construction that achieves high power density through flux focusing, but in contrast to the approach of Prof K
Binns, also achieves a cost effective design regarding manufacturability. The work in this thesis considers the use of 2D finite element techniques that is used to handle the electromagnetic part of the design process and provides the way in which its results identify benefits that arise from use of different forms of the rotor geometries.
New design principles are described and methods of analyzing and predicting the motor performance from design data are presented and validated by comparisons of experimental and predicted results.
A motor design programme is developed and its design format is presented. The essential technical features of a proposed integral power electronic controller are described. The methods of selecting an appropriate motor for an application, simulation and prediction of motor performance, thermal analysis and acceleration performance are all presented and validated by experimental measurement.
The constructional features land the design techniques of the 3-phase permanent magnet brushless dc motor developed in this study have been applied to a number of commercial
aerospace and defence applications and have proved to be extremely effective and competitive. Typical practical examples of applications are presented.
The challenge of the study was to improve motor efficiency significantly and to design a motor that can withstand very high peripheral speeds while at the same time develop high
power density without suffering from overheating. These special requirements are typical in modern aerospace and defence applications.

This thesis supplied via ROAR to UEL-registered users is protected by copyright and other intellectual property rights, and duplication of any part of the material is not permitted, except for your personal use for the purposes of non-commercial research and private study in electronic or print form. You must obtain permission from the copyright-holder for any other use. Electronic or print copies may not be offered, for sale or otherwise, to anyone. No quotation from the thesis may be published without proper acknowledgement.