Linear Electric Actuators And Generators

by I. Boldea , Syed A. Nasar

• ISBN13: 9780521020329
• ISBN10: 0521020328
• Format: Paperback
• Copyright: 2005-09-26
• Publisher: Cambridge University Press

Summary

Linear electric actuators (LEAs) and linear electric generators (LEGs) are widely used electromagnetic devices. 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.

Table of Contents

Preface	ix
CHAPTER 1 Magnetic Circuits, Fields, and Forces	1	(32)
1.1 A Review of Electromagnetic Field Theory	2	(5)
1.2 Magnetic Materials	7	(4)
1.3 Magnetic Losses	11	(2)
1.4 Magnetic Circuits	13	(3)
1.5 Ampere's Law Applied to a Magnetic Circuit	16	(1)
1.6 Limitations of the Magnetic Circuit Approach	17	(2)
1.7 Energy Relations in a Magnetic Field	19	(1)
1.8 Inductance	19	(3)
1.9 Magnetic Circuits Containing Permanent Magnets	22	(5)
1.10 Forces of Electromagnetic Origin	27	(1)
1.11 The Force Equation	28	(4)
References	32	(1)
CHAPTER 2 Introduction to Linear Electric Actuators and Generators	33	(12)
2.1 Terminology	33	(3)
2.2 Operation of LEAs	36	(3)
2.3 Operation of LEGs	39	(1)
2.4 Existing and Potential Applications	40	(3)
References	43	(2)
CHAPTER 3 Linear Induction Actuators	45	(46)
3.1 Performance Specifications	45	(1)
3.2 Construction Details for Flat and Tubular Geometries	46	(8)
3.3 Field Distributions	54	(4)
3.4 Lumped Parameter Representation	58	(3)
3.5 Steady-State Characteristics	61	(7)
3.6 State-Space Equations	68	(2)
3.7 Vector Control Aspects	70	(5)
3.8 Design Methodology by Example	75	(13)
References	88	(3)
CHAPTER 4 Linear Permanent Magnet Synchronous Actuators	91	(44)
4.1 Construction Details	91	(1)
4.2 Fields in LPMSAs	92	(2)
4.3 Sinusoidal Current Model Field Distribution	94	(3)
4.4 The dq-Model and Forces	97	(5)
4.5 Rectangular Current Mode	102	(3)
4.6 Dynamics and Control Aspects	105	(8)
4.7 Design Methodology	113	(19)
References	132	(3)
CHAPTER 5 Linear Reluctance Synchronous Actuators	135	(28)
5.1 Practical Configurations and Saliency Coefficients	136	(5)
5.2 Field Distributions and Saliency Ratio	141	(3)
5.3 Mathematical Model	144	(3)
5.4 Steady-State Characteristics	147	(4)
5.5 Vector Control Aspects	151	(1)
5.6 Design Methodology	152	(9)
References	161	(2)
CHAPTER 6 Linear Switched Reluctance Actuators	163	(16)
6.1 Practical Configurations	163	(4)
6.2 Instantaneous Thrust	167	(3)
6.3 Average Thrust	170	(1)
6.4 Converter Rating	171	(1)
6.5 State-Space Equations	172	(1)
6.6 Control Aspects	172	(1)
6.7 Design Methodology	173	(5)
References	178	(1)
CHAPTER 7 Linear Stepper Actuators	179	(22)
7.1 Practical Configurations and Their Operation	180	(3)
7.2 Static Forces	183	(1)
7.3 Lumped Parameter Models	184	(4)
7.4 Control Aspects	188	(5)
7.5 LSA Design Guidelines	193	(6)
References	199	(2)
CHAPTER 8 Linear Electric Generators	201	(34)
8.1 Principle of Operation and Basic Configurations	201	(2)
8.2 Moving Magnet Linear Alternators	203	(7)
8.3 Moving Iron Linear Alternators	210	(13)
8.4 Stability Considerations	223	(9)
8.5 Choice of Tuning Capacitor	232	(1)
References	233	(2)
Index	235