E-Book Overview
This book deals with LEAs that convert electric energy into controlled mechanical motion of limited travel and LEGs that transform mechanical energy into electric energy. Examples range from loudspeakers and microphones to magnetically levitated material transfer in ultraclean rooms. Much of the literature on linear actuators and generators covers the principles of operation and performance calculations of these devices. Little has been published on their control or on detailed design methodologies. This book presents the first unified treatment of the subject, including the construction, operation, control, and design of LEAs and LEGs. Chapters describe linear induction, permanent-magnet, linear reluctance, switched reluctance, and linear stepper actuators, as well as various types of linear electric generators. The text is amply illustrated with numerous design examples, and will appeal to graduate students and researchers in electrical, mechanical, and design engineering.
E-Book Content
LINEAR ELECTRIC ACTUATORS AND GENERATORS LINEAR ELECTRIC ACTUATORS AND GENERATORS I. Boldea Polytechnic Institute, Timisoara, Romania Syed A. Nasar University of Kentucky CAMBRIDGE UNIVERSITY PRESS CAMBRIDGE UNIVERSITY PRESS Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, Sao Paulo Cambridge University Press The Edinburgh Building, Cambridge CB2 2RU, UK Published in the United States of America by Cambridge University Press, New York www.cambridge.org Information on this title: www.cambridge.org/9780521480178 © Cambridge University Press 1997 This publication is in copyright. Subject to statutory exception and to the provisions of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press. First published 1997 This digitally printed first paperback version 2005 A catalogue recordfor this publication is available from the British Library Library of Congress Cataloguing in Publication data Boldea, I. Linear electric actuators and generators / 1 . Boldea, Sayed A. Nasar p. cm. Includes bibliographical references and index. ISBN 0-521^8017-5 (he) I. Electric generators. 2. Actuators. I. Nasar, S. A. II. Title. TK2411.B6 1997 629.8'315-dc20 96-31469 CIP ISBN-13 978-0-521-48017-8 hardback ISBN-10 0-521-48017-5 hardback ISBN-13 978-0-521 -02032-9 paperback ISBN-10 0-521-02032-8 paperback CONTENTS Preface ix CHAPTER 1 Magnetic Circuits, Fields, and Forces 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 1.10 1.11 A Review of Electromagnetic Field Theory Magnetic Materials Magnetic Losses Magnetic Circuits Ampere's Law Applied to a Magnetic Circuit Limitations of the Magnetic Circuit Approach Energy Relations in a Magnetic Field Inductance Magnetic Circuits Containing Permanent Magnets Forces of Electromagnetic Origin The Force Equation References 2 7 11 13 16 17 19 19 22 27 28 32 VI CONTENTS CHAPTER 2 Introduction to Linear Electric Actuators and Generators 2.1 2.2 2.3 2.4 Terminology Operation of LEAs Operation of LEGs Existing and Potential Applications References CHAPTER 3 Linear Induction Actuators 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 Performance Specifications Construction Details for Flat and Tubular Geometries Field Distributions Lumped Parameter Representation Steady-State Characteristics State-Space Equations Vector Control Aspects Design Methodology by Example References CHAPTER 4 Linear Permanent Magnet Synchronous Actuators 4.1 4.2 4.3 4.4 4.5 4.6 4.7 Construction Details Fields in LPMSAs Sinusoidal Current Model Field Distribution The dg-Model and Forces Rectangular Current Mode Dynamics and Control Aspects Design Methodology References CHAPTER 5 Linear Reluctanc