Table Of ContentElectromagnetic Devices for Motion Control
and Signal Processing
Signal Processing and Digital Filtering
Synthethic Aperture Radar
J.P. Fitch
Multiplicative Complexity, Convolution and the DFT
M.T. Heideman
Array Signal Processing
S.u. Pillai
Maximum Likelihood Deconvolution
J.M. Mendel
Algorithms for Discrete Fourier Transform and Convolution
R. Tolimieri, M. An, C. Lu
Algebraic Methods for Signal Processing and Communications Coding
R.E. Blahut
Electromagnetic Devices for Motion Control and Signal Processing
Y.M. Pulyer
Yuly M. Pulyer
Electromagnetic Devices
for Motion Control
and Signal Processing
C.S. Burrus
Consulting Editor
With 126 Illustrations
Springer-Verlag
New York Berlin Heidelberg London Paris
Tokyo Hong Kong Barcelona Budapest
Yuly M. Pulyer
Consultant, Magnetic Devices and Signal Processing
Malden, MA 02148
USA
Consulting Editor Technical Editors
Signal Processing and Digital Filtering Corine A. Bickley
Research Laboratory of Electronics
C.S. Burrus and
Professor and Chairman Program in Writing and
Department of Electrical Humanistic Studies
and Computer Engineering Massachusetts Institute of Thchnology
Rice University Cambridge, MA 02139
Houston, TX 77251-1892 USA
USA
Philip A. von Guggenberg
Laboratory for Electromagnetic
and Electronic Systems
Massachusetts Institute of Thchnology
Cambridge, MA 02139
USA
Library of Congress Cataloging-in-Publication Data
Pulyer, Yuly M.
Electromagnetic devices for motion control and signal processing I
Yuly M. Pulyer.
p. cm.
Includes bibliographical references and index.
ISBN-13: 978-1-4612-7723-1 e-ISBN-13: 978-1-4612-2928-5
DOI:1O.1007t978-1-4612-2928-5
1. Electromagnetic devices. 2. Signal processing. 3. Motion
control devices. I. Title.
TK7872.M25P85 1992
621.3 - dc20 92-3200
Printed on acid-free paper.
© 1992 Springer-Verlag New York, Inc.
Softcover reprint of the hardcover 1s t edition 1992
All rights reserved. This work may not be translated or copied in whole or in part without the
written permission of the publisher (Springer-Verlag New York, Inc., 175 Fifth Avenue, New
York, NY 10010, USA), except for brief excerpts in connection with reviews or scholarly
analysis. Use in connection with any form of information storage and retrieval, electronic
adaptation, computer software, or by similar or dissimilar methodology now known or hereaf
ter developed is forbidden.
The use of general descriptive names, trade names, trademarks, etc., in this publication, even if
the former are not especially identified, is not to be taken as a sign that such names, as
understood by the Trade Marks and Merchandise Marks Act, may accordingly be used freely by
anyone.
Production managed by Hal Henglein; manufacturing supervised by Vincent Scelta.
Camera-ready copy prepared by the author.
987654321
Preface
This book is dedicated to electrical and mechanical engineers
involved with the design of magnetic devices for motion con
trol and other instrumentation that uses magnetic principles
and technology. It can be of benefit to graduate and postgrad
uate students to gain experience with electro-magnetic princi
ples and also with different aspects of magnetic coupling mech
anisms and magnetic circuitry analysis for the design of devices
such as electrical servo motors, tachogenerators, encoders, gyro
magnetic suspension systems, electro-magnetic strip lines, and
other electro-magnetic instruments.
The rapidly growing areas of production automation, robotics,
precise micro-electronics, and pilot navigation place demands on
motion control technology in terms of accuracy, reliability, cost
effectiveness, and miniaturization. New ferromagnetic materials
having quasi-linear and non-linear high-squareness characteris
tics as well as high-energy permanent magnets, fine lithography,
and high-t.emperature superconductivit.y (t.o be expected com
mercially) motivate the implementation of new motion control
components that exploit these new materials and technologies.
This book presents classical miniature electrical machine de
signs as well as several modifications in the geometry of mag
netic couplings which lead to new motor and encoder design
methodologies and other motion control devices such as new
coil deposition patterns for incremental and absolute encoders,
free spherical gyro suspension in a traveling magnetic field for
navigation instrumentation, and magnetic strip lines in combi
nation with resistive and capacitive media to generate a variety
of low-noise LC filters and other signal processing devices.
A miniature electrical machine must be considered to be a
high-accuracy instrument. This book also develops a mini elec
trical machine analytical model as a distributed parameter mag
netic circuit, which is an instructive tool for determination of
B-field distribution accuracy and mutual coupling analysis in
terms of the influence of basic mechanical tolerances and core
B(H) non-linearities as a source of non-linear distortions in sine
vi Preface
and cosine transformers as vector composers or decomposers and
high-resolution encoders. In addition, this model provides an an
alytical tool for investigating new capabilities in torque control
by controlling motor core B(H) saturation. This model is in
the form of a closed-ring magnetic transmission line coupled to
a closed electrical transmission line which simulates the rotor
reaction due to conductive stationary or rotary media in the
form of AC thin-walled or squirrel cage rotors or thin resistive
or capacitive strips.
Another goal of this book is to generate and motivate a cr~
ative approach to the design of electro-magnetic devices that
have similar physics in terms of magnetic coupling and hence
similar magnetic circuit models but different geometries and
functionalities for torque generation or motion encoding. This
book is also oriented toward the exchange of ideas in concepts
of the design of electro-magnetic motion control devices and the
development of analytical engineering tools for computation and
optimization.
The author realizes that this book is not free of errors, for
which he apologizes; he would greatly appreciate any comments
regarding this book.
Acknowledgments
This book was written as the result of more than 30 years
of working in the area of motion control devices. A substantial
contribution to this job was made by many of my graduate and
post-graduate students in the former Soviet Union, particularly
Drs. E. Asinovsky, Y. Kolesov, and M. Leukovich. Their efforts
and talent are greatly appreciated. I would also like to mention
well-known experts in mini electrical machine technology in the
former Soviet Union: Prof. D. Swetcharnic, Prof. Y. Chechet,
Prof. I. Kopilov, Prof. V. Lomonosov, Dr. E. Lopuchina, Dr. G.
Somichina, and Dr. I. Vevurko (inventor of the brushless motor
concept in Russia in the late 1950s). To all of these and other
colleagues the author is highly grateful for the many interesting
discussions that contributed to this book. The author also grate
fully acknowledges the contribution made by Anthony Lawrence
of Northrop Corporation for support and assistance in the de
velopment of the free gyro suspension concept discussed in this
book. Technical editing was provided by Philip von Guggenberg
of the Massachusetts Institute of Technology. It is the author's
pleasure to express his deep appreciation to MIT professor Dr.
Corine Bickley for her unique expertise and effort in the creative
editing of this book. Her talent and devotion made a substantial
contribution to bringing this book to publication.
Contents
Preface .. v
Acknowledgments . Vll
1 Overview of the Development and Application
of Electrical Machines 1
2 Generalized AC Machines for the Design of Motion
Control Devices 13
2.1 The vector property of the GEM system . . . 13
2.2 The coil spatial mmf sinusoidal distribution . 17
2.3 Principal devices as GEM design derivatives . 26
3 Magnetic Transmission Line 67
3.1 Introduction: Distributed parameter electro-magnetic
circuits. . . . . . . . . . . . . . . . . 67
3.2 Electro-magnetic system differential equations. 75
3.3 The core slot slashing concept. . . . . . . 83
3.4 Teeth air gap harmonic analysis. . . . . 90
3.5 Thin-walled rotary cylinder model (TCR) . . . . 100
3.6 Rotary cylinder equivalent circuit as an analogue
to an electrical transmission line ........ . 104
3.7 The TCR and SCR self-inductance computational
approach. . . . . . . . . . . . . .. . 106
3.8 Magnetic transmission line equations for sinusoidal
systems .. . . . . . . . . . .. .. .. . 111
3.9 Torque function for TCR and SCR motors. . . .. . 128
3.10 Teeth variable permeance torque estimate . . . . 132
3.11 Permanent magnet switch phase synchronic motor . 144
3.12 Hysteresis motor: principal physics and
computational approach . . . . . . . . . . . .. . 163
3.13 Electro-magnetic circuit for a generalized electrical
machine geometry (GEM) . . . .. ... . 168
x Contents
3.14 Induction tachogenerator (ITG) . .169
3.15 Resolver-Motor ......... . .173
3.16 Sin-Cos transformer magnetic circuit in general form . 177
4 Motor Drive Circuits 181
4.1 Brief overview of closed-loop motor drive circuits . 181
4.2 Self-oscillatory synchronic motor drive system. . 182
4.3 AC motor-magnetic amplifier integrity . . . . . 188
4.4 Analytical consideration of the MMA concept . . 194
4.5 Simplified engineering approach . . . . . . . . . . 205
4.6 The over-synchronic speed motor control concept . 231
5 Technological Inaccuracy in the Performance
of Small Electrical Machines 240
5.1 Errors due to eccentricity of the internal rotation core 240
5.2 Errors due to external core air gap elliptical
irregulari ty ................. . .249
5.3 Thin-walled rotor thickness irregularity .. .258
5.4 Desirable aspects of geometrical irregularity .265
6 Theory of Precise Sinusoidal Windings 271
6.1 Slotwise coil mmf analysis ................ 271
6.2 A design methodology for symmetric two-phase coils . 278
6.3 Condition to obtain the maximal coil Q-factor . . 283
6.4 Two-pole sin-cos system . . . . . . . . . . . . 286
6.5 Poly-pole coil sin-cos transformer . . . . . . . 288
6.6 Determination of slot numbers to minimize
undesirable harmonics . . . . . . . . . . 297
6.7 Ultra periodicity lithography systems. . 301
6.8 U-syne encoder concept ....... . . 311
6.9 High-resolution brushless encoders . . . 318
6.10 Digital interpolation concepts for encoder resolution
multiplication . . . . . . . . . . . . . . . . . . .. . 323
7 Induction Ferromagnetic Core Position Sensors 339
7.1 Slotwise brushless miniature systems . . . . . .. . 339
7.2 Multi-periodical brushless system "Indusyn" . .. . 347
7.3 Brushless permag DC motor integrated position
encoder .. . . . . . . . . . . . . . . . . . . . .. . 357
Contents xi
7.4 Long-range angular linearity induction
........
potentiometers (LIP) .......... .376
........
7.5 LIP with a range of ±160 degrees ... .387
7.6 "Sliding magnetic contact" induction potentiometer .391
7.7 Unipolar type of brushless system of ±90 LIP range .394
7.8 Brushless differential transformer type of LIP ±90 .398
7.9 DC brushless potentiometer by using
.....
magneto-resistors ............... .401
7.10 DC logometric torque actuator on the basis
of the ±90 degrees LIP .......... ..... .404
8 Spherical AC Electro-machine Systems
as Free Gyro Instruments 408
8.1 Introduction..................... . 408
8.2 Analytical model of the spherical gyro-magnetic
suspension system ......... . 416
8.3 Rotor current differential equation . 422
8.4 Force computation . . . . . . . . . . . 429
8.5 Impedance match condition in view
of superconductivity . 445
8.6 Feedback control . . . . . . . . . . . . 446
9 Electro-magnetic Strip Transmission Line Devices 450
9.1 General introduction ................... 450
9.2 The It - P strip MTL structure ............. 451
9.3 The Il-P-f-Il electro-magnetic and magneto-electric
structure ................... . .456
9.4 Two-port Il-air-Il structures as magnetic
analog-digitallogometers. . . . . . . . . . . .459
Appendix 464
Index 467
