85797
20180501105856.0
10.5075/epfl-thesis-3569
doi
urn:nbn:ch:bel-epfl-thesis3569-2
urn
5168778
nebis
THESIS_LIB
eng
3569
Comparative study and selection criteria of linear motors
Lausanne
2006
EPFL
2006
239
Theses
Initially, linear motors have been particularly dedicated to transportation systems. Nowadays, linear motors are meant to replace a system using a rotating motor and a transmission to realize a linear movement. With linear motors the performances increase considerably since the mechanical limitations are removed. This leads to a better precision, a higher acceleration and a higher speed of the moving part. Therefore, direct drives with linear motors are increasingly used in industrial applications although these solutions need often more investment costs. Different linear motor structures and technologies exist. They can be either induction or synchronous motors with a transverse or a longitudinal flux. Furthermore, linear motors may have several topologies. They can be either long or short stator and double or single sided. All these variants may be combined giving therefore numerous possibilities to perform a linear movement. Hence, to make the best choice for a given application, a global methodology based on the comparison of optimized motors is presented in the thesis. This design methodology is based on figure of merits which are bound to the specifications of the studied application. This method differs from a conventional one since optimized motors with the same objective function are compared. The optimized motors are obtained by an indirect method based on an optimization algorithm (Sequential Quadratic Programming, SQP). An indirect approach differs from the conventional deterministic one for which at least one parameter must be fixed to obtain a motor pre design, since there are constraints and validity domain which are introduced. The proposed methodology can be applied either to rotating or to linear motor design. The use of an optimization program to perform motor designs requires analytical motor models. The models developed in this thesis take into account the thermal behavior of the motors in order to achieve more realistic results. Furthermore, the analytical models of synchronous motors are thoroughly studied leading to several interesting conclusions. They are based on well known algorithms developed for rotating motors. The proposed models are very accurate in comparison with the FEM program, except for a transversal flux linear motor for which the obtained results are not worthwhile enough to be optimized. This is caused by the structure of the motor which is close to a reluctant motor and imposes to model the motor by a lumped magnetic scheme. Moreover, a global analysis of the windings due to the particularity of linear motor to have an even or odd number of poles is presented in the thesis. The methodology proposed in the thesis is successfully used for an innovative application which deals with a multi mobile system for a lift. For this lift, several cabins travel in the same shaft implying linear motors to move autonomously each cabin. First, by comparing the different motor technologies, the best motor type is selected. Afterwards, the motor windings for the selected motors are analyzed and compared in order to find the most adapted one for this application. The motor is finally optimized, leading to a motor design proposal. This motor design takes into account the thermal behavior, the material cost and the electrical characteristic of the linear motor.
linear motors
analytical models
design methodology
comparison methodology
optimization processes
lift system
multi mobile system
moteurs linéaires
modèles analytiques
méthodologie de dimensionnement et de comparaison
processus d'optimisations
technologie pour ascenseur
Chevailler, Samuel
115273
(EPFLAUTH)115273
Jufer, Marcel
dir.
105519
240205
Texte intégral / Full text
5122719
Texte intégral / Full text
http://infoscience.epfl.ch/record/85797/files/EPFL_TH3569.pdf
LAI
252066
U10351
oai:infoscience.tind.io:85797
DOI
DOI2
thesis-bn2018
thesis
STI
STI
EDPR
LAI
2006-7-3
2006
3569/THESES
EPFL
PUBLISHED
THESIS