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Analysis of the work of brushless motor with cylindrical winding and external rotor

Marcin Ziółek

Abstract

This dissertation concerns the problem of minimizing of cogging torque in electromagnetic torque in two modular brushless motor with permanent magnets, transverse magnetic flux, cylindrical coil and external rotor. Cogging torque is produced by interaction of permanent magnets and stator. The permanent magnets are placed on the rotor. The stator has variable magnetic conductivity, which depends on the angle of rotation. Cogging torque is negative phenomenon, because it increases vibration, stress, noise and causes additional power losses. Cogging torque leads to premature wear of components and bigger power consumption when the motor starts. Given the high cost of building a prototype motor, the important thing at the design stage is the selection of the design parameters of the magnetic circuit, for which the cogging torque has the smallest value. The aim of this study was to minimize the cogging torque in electromagnetic torque for this construction of motor. Minimization of cogging torque in electromagnetic torque has obtained as a result of solving electromagnetic circuits as the following models of motors. In this paper I examined the impact of the span of the magnets, the width of the cogs, the number of pairs of poles, the distance between machine modules and the thickness of the air gap for the cogging torque and for the electromagnetic torque. As a result of the computer simulation I determined the parameters of motor, for which cogging torque in electromagnetic torque is repeatedly smaller compared to the original version of the machine. In order to verify the accuracy of the calculations, the new prototype of the motor has been built. The results of the experiment confirmed the accuracy of the calculations. The developed motor prototype can be used as the drive for electric vehicles. In the final part of this paper I compared the results of the analyzes and draws the conclusions. A significant reduction of cogging torque was achieved by proper selection of the span magnets, the width of the cogs and the distance between machine modules. The increase in the number of cogs in the motor caused a clear increase of the electromagnetic torque.
Record ID
WUTcaea63c827aa49aeb6d2a0c8c4e5dd7b
Diploma type
Doctor of Philosophy
Author
Marcin Ziółek Marcin Ziółek,, Undefined Affiliation
Title in Polish
Analiza pracy silnika bezszczotkowego z cylindrycznym uzwojeniem i zewnętrznym wirnikiem
Title in English
Analysis of the work of brushless motor with cylindrical winding and external rotor
Language
(pl) Polish
Certifying Unit
Faculty of Electrical Engineering (FoEE)
Discipline
electronic engineering / (technology domain) / (technological sciences)
Status
Finished
Start date
25-09-2013
Defense Date
23-04-2014
Title date
21-05-2014
Supervisor
Zbigniew Goryca Zbigniew Goryca,, External affiliation of publication: Kielce University of Technology
Internal reviewers
External reviewers
Tadeusz Glinka Tadeusz Glinka,, External affiliation of publication: Silesian University of Technology
Pages
110
Keywords in English
cogging torque, electromagnetic torque, brushless motor, permanent magnets, transverse magnetic flux, external rotor, cylindrical coil
Abstract in English
This dissertation concerns the problem of minimizing of cogging torque in electromagnetic torque in two modular brushless motor with permanent magnets, transverse magnetic flux, cylindrical coil and external rotor. Cogging torque is produced by interaction of permanent magnets and stator. The permanent magnets are placed on the rotor. The stator has variable magnetic conductivity, which depends on the angle of rotation. Cogging torque is negative phenomenon, because it increases vibration, stress, noise and causes additional power losses. Cogging torque leads to premature wear of components and bigger power consumption when the motor starts. Given the high cost of building a prototype motor, the important thing at the design stage is the selection of the design parameters of the magnetic circuit, for which the cogging torque has the smallest value. The aim of this study was to minimize the cogging torque in electromagnetic torque for this construction of motor. Minimization of cogging torque in electromagnetic torque has obtained as a result of solving electromagnetic circuits as the following models of motors. In this paper I examined the impact of the span of the magnets, the width of the cogs, the number of pairs of poles, the distance between machine modules and the thickness of the air gap for the cogging torque and for the electromagnetic torque. As a result of the computer simulation I determined the parameters of motor, for which cogging torque in electromagnetic torque is repeatedly smaller compared to the original version of the machine. In order to verify the accuracy of the calculations, the new prototype of the motor has been built. The results of the experiment confirmed the accuracy of the calculations. The developed motor prototype can be used as the drive for electric vehicles. In the final part of this paper I compared the results of the analyzes and draws the conclusions. A significant reduction of cogging torque was achieved by proper selection of the span magnets, the width of the cogs and the distance between machine modules. The increase in the number of cogs in the motor caused a clear increase of the electromagnetic torque.
PKT classification
430000
KBN classification
34
Thesis file
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Uniform Resource Identifier
https://repo.pw.edu.pl/info/phd/WUTcaea63c827aa49aeb6d2a0c8c4e5dd7b/
URN
urn:pw-repo:WUTcaea63c827aa49aeb6d2a0c8c4e5dd7b

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