Electromagnetic Devices for Motion Control and Signal Processing

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.

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This book presents an analytic tool for examining the design of small electromagnetic devices such as machines, encoders, magnetic strip lines, and other devices. The geometry and magnetic circuit analyses for these devices is based on a differential equation, called the magnetic transmission line equation, derived from Ampere's Law; it is similar to the electric transmission line equation. The analysis includes both uniform and nonuniform geometries, including nonuniformities resulting from manufacturing errors, and leads to a new class of designs for miniature machines and other devices. The magnetic circuit analysis involves both undesirable characteristics (such as core loss and nonlinear distortion in precise, high-resolution encoders), and also desirable aspects that can be used in the form of AC motor-amplifier integrity, hysteresis motors, magnetic encoders, etc. The more than 125 figures serve to visualize the magnetic coupling geometry, the physics of the conceptual design, and the analytical tools.

Contenu
1 Overview of the Development and Application of Electrical Machines.- 2 Generalized AC Machines for the Design of Motion Control Devices.- 2.1 The vector property of the GEM system.- 2.2 The coil spatial mmf sinusoidal distribution.- 2.3 Principal devices as GEM design derivatives.- 3 Magnetic Transmission Line.- 3.1 Introduction: Distributed parameter electro-magnetic circuits.- 3.2 Electro-magnetic system differential equations.- 3.3 The core slot slashing concept.- 3.4 Teeth air gap harmonic analysis.- 3.5 Thin-walled rotary cylinder model (TCR).- 3.6 Rotary cylinder equivalent circuit as an analogue to an electrical transmission line.- 3.7 The TCR and SCR self-inductance computational approach.- 3.8 Magnetic transmission line equations for sinusoidal systems.- 3.9 Torque function for TCR and SCR motors.- 3.10 Teeth variable permeance torque estimate.- 3.11 Permanent magnet switch phase synchronic motor.- 3.12 Hysteresis motor: principal physics and computational approach.- 3.13 Electro-magnetic circuit for a generalized electrical machine geometry (GEM).- 3.14 Induction tachogenerator (ITG).- 3.15 Resolver-Motor.- 3.16 Sin-Cos transformer magnetic circuit in general form.- 4 Motor Drive Circuits.- 4.1 Brief overview of closed-loop motor drive circuits.- 4.2 Self-oscillatory synchronic motor drive system.- 4.3 AC motor-magnetic amplifier integrity.- 4.4 Analytical consideration of the MMA concept.- 4.5 Simplified engineering approach.- 4.6 The over-synchronic speed motor control concept.- 5 Technological Inaccuracy in the Performance of Small Electrical Machines.- 5.1 Errors due to eccentricity of the internal rotation core.- 5.2 Errors due to external core air gap elliptical irregularity.- 5.3 Thin-walled rotor thickness irregularity.- 5.4 Desirable aspects of geometrical irregularity.- 6 Theory of Precise Sinusoidal Windings.- 6.1 Slotwise coil mmf analysis.- 6.2 A design methodology for symmetric two-phase coils.- 6.3 Condition to obtain the maximal coil Q-factor.- 6.4 Two-pole sin-cos system.- 6.5 Poly-pole coil sin-cos transformer.- 6.6 Determination of slot numbers to minimize undesirable harmonics.- 6.7 Ultra periodicity lithography systems.- 6.8 U-syne encoder concept.- 6.9 High-resolution brushless encoders.- 6.10 Digital interpolation concepts for encoder resolution multiplication.- 7 Induction Ferromagnetic Core Position Sensors.- 7.1 Slotwise brushless miniature systems.- 7.2 Multi-periodical brushless system Indusyn.- 7.3 Brushless permag DC motor integrated position encoder.- 7.4 Long-range angular linearity induction potentiometers (LIP).- 7.5 LIP with a range of ±160 degrees.- 7.6 Sliding magnetic contact induction potentiometer.- 7.7 Unipolar type of brushless system of ±90 LIP range.- 7.8 Brushless differential transformer type of LIP ±90.- 7.9 DC brushless potentiometer by using magneto-resistors.- 7.10 DC logometric torque actuator on the basis of the ±90 degrees LIP.- 8 Spherical AC Electro-machine Systems as Free Gyro Instruments.- 8.1 Introduction.- 8.2 Analytical model of the spherical gyro-magnetic suspension system.- 8.3 Rotor current differential equation.- 8.4 Force computation.- 8.5 Impedance match condition in view of superconductivity.- 8.6 Feedback control.- 9 Electro-magnetic Strip Transmission Line Devices.- 9.1 General introduction.- 9.2 The ? ? strip MTL structure.- 9.3 The ? ? ?? electro-magnetic and magneto-electric structure.- 9.4 Two-port ? air? structures as magnetic analog-digital logometers.