Modern Permanent Magnet Electric Machines. Theory and Control

Description

Cover Half Title Title Page Copyright Page Contents Preface 1. FUNDAMENTALS OF MAGNETISM 1.1. Atom, spin, magnetic dipole moment 1.2. Magnetic permeability, magnetization vector, magnetic susceptibility 1.3. Classification of materials according to magnetic permeability 1.4. Hysteresis loop of ferromagnetic materials 1.5. Comparison of soft and hard magnetic materials 1.6. Analogies in electric and magnetic circuits 1.7. Effect of ferromagnetic core inside a coil 1.8. Applications of magnetism 1.8.1. Electric motors and generators 1.8.2. Magnetic storage of data 1.8.3. Loudspeakers 1.8.4. Lift electromagnet 1.8.5. Magnetic core memory 1.8.6. Magnetoresistive random-access memory (MRAM) 1.8.7. Cathode ray tube (CRT) 1.8.8. Nuclear magnetic resonance (NMR) spectroscopy 1.8.9. Magnetic resonance imaging (MRI) 1.8.10. Magnetic levitation 1.8.11. Cyclotrons 1.8.12. Tokamak 1.8.13. MHD generators 1.9. Biot-Savart law, Faraday’s law and Gauss’s law 1.9.1. Biot–Savart law 1.9.2. Faraday’s law 1.9.3. Gauss’s law 1.10. Maxwell’s equations 1.10.1. Maxwell’s first equation 1.10.2. Maxwell’s second equation 1.10.3. Maxwell’s third equation 1.10.4. Maxwell’s fourth equation 1.11. Magnetic vector potential 1.12. Speed of electromagnetic wave and theory of relativity 1.13. Maxwell’s equations in application to electrical machines 1.14. Force in electromagnetic field Summary 2. SOFT MAGNETIC MATERIALS 2.1. Classification of soft ferromagnetic materials 2.1.1. Laminated silicon steels 2.1.2. High-saturation cobalt alloys 2.1.3. Amorphous ferromagnetic alloys 2.1.4. Soft magnetic composites (SMC) 2.1.5. Permalloys 2.1.6. Nanocrystalline composites 2.1.7. Solid ferromagnetic steels 2.2. Losses in ferromagnetic materials 2.2.1. Hysteresis losses 2.2.2. Eddy-current losses 2.2.3. Excess eddy-current losses 2.2.4. Additional losses 2.3. Engineering approach to calculation of core losses 2.4. Ferromagnetic cores 2.4.1. Transformers 2.4.2. Electronic devices 2.4.3. DC machines 2.4.4. Switched reluctance machines (SRM) 2.4.5. Induction machines 2.4.6. Synchronous turbogenerators 2.4.7. Synchronous hydrogenerators 2.4.8. Permanent magnet (PM) brushless motors 2.4.9. Segmented stator and rotor cores 2.4.10. 3D cores made of soft magnetic composites (SMC) for special electric machines 2.4.11. Solid ferromagnetic rotors 2.5. Magnetic circuits of electrical machines for recycling Summary 3. PERMANENT MAGNETS 3.1. Early history of permanent magnets (PM) 3.2. Earth’s magnetic field 3.3. What is a permanent magnet (PM)? 3.4. Hysteresis loop, demagnetization curve, recoil line, magnetic energy density and intrinsic magnetization 3.5. Temperature coefficients and Curie temperature 3.6. PM materials used in construction of electrical machines 3.6.1. Alnico 3.6.2. Ferrites 3.6.3. Rare-earth magnets SmCo and NdFeB 3.7. Nanocomposite magnets 3.8. Shape of demagnetization curves of ferrite and rare earth PMs 3.9. Simplified method of finding the operating point of a PM 3.10. Main flux and leakage flux 3.11. B–H and Φ–F coordinate systems 3.12. Operating point for PM magnetized outside the machine 3.12.1. PM without pole shoes in open space 3.12.2. PM with pole shoes in open space 3.12.3. PM inside an external magnetic circuit 3.12.4. PM with a complete external armature system 3.13. Operating point for magnetization without armature 3.14. Mallinson–Halbach array Summary 4. CALCULATION OF MAGNETIC CIRCUITS WITH PMs 4.1. Methods of calculation of magnetic circuits with PMs 4.2. Permeance evaluation by dividing the magnetic field into simple solids 4.3. Graphical methods 4.4. Analytical approach to calculation of magnetic circuits with PMs 4.5. Calculation of magnetic circuits with PMs using an equivalent reluctance network 4.6. Calculation of magnetic circuits with PMs using the FEM Summary 5. PM BRUSH DC MACHINES AND THEIR CONTROL 5.1. Why PM machines? 5.2. Construction of a brush-type PM DC machine 5.3. Principle of operation of a PM brush DC machine 5.4. Windings of a slotted rotor (armature) of a brush-type DC machine 5.5. Construction of a coreless rotor winding with an inner PM 5.6. Coreless rotor windings: Maxon versus Faulhaber winding 5.7. PM brush DC motor with cylindrical rotor and foil winding 5.8. Disk-type PM brush DC motors with printed rotor winding 5.9. Fundamentals of transient analysis of PM brush DC motors 5.10. Speed control of a brush-type PM DC motor 5.10.1. Three-phase fully controlled rectifier 5.10.2. Chopper 5.10.3. H-bridge 5.11. PM brush DC servomotors 5.12. Applications of brush-type PM DC motors 5.12.1. Toys 5.12.2. Auxiliary motors for automobiles 5.12.3. Vibration motors for mobile phones 5.12.4. Robotic vehicles for Mars missions Summary 6. PM BRUSHLESS DC MOTORS AND DRIVE CONTROL 6.1. From PM DC brushed to PM DC brushless motors 6.2. Construction of rotors 6.3. Sinusoidally excited and square wave motors 6.4. Method of changing DC bus voltage and speed control 6.5. Unipolar and bipolar operating mode 6.6. Six-step commutation: two phases on 6.7. Three phases on: 180-degree conduction 6.8. Rotor position sensing 6.8.1. Hall sensors 6.8.2. Encoders 6.8.3. Resolvers 6.8.4. Sensorless control 6.9. Mathematical model 6.10. Cogging torque 6.11. The smallest and the biggest PM brushless motors in the world 6.12. Wiring diagram for a solid-state converter-fed PM brushless motor 6.13. Integrated circuits (IC) for control of PM brushless motors 6.14. Practical electromechanical drive system 6.15. Selected applications 6.15.1. Computer hard disk drives (HDD) 6.15.2. Two-phase PM brushless motors for computer cooling fans 6.15.3. PM brushless motors integrated with an electronic control circuit 6.15.4. Hybrid electric vehicles Summary 7. PM SYNCHRONOUS MOTORS AND DRIVE CONTROL 7.1. Fundamental equations for synchronous machines 7.1.1. Speed 7.1.2. Air gap magnetic flux density 7.1.3. Electromotive force (EMF) 7.1.4. Armature line current density and current density 7.1.5. Electromagnetic power 7.1.6. Synchronous reactance 7.2. Location of the armature current in the d-q coordinate system 7.3. Armature reaction 7.4. Phasor diagram 7.5. Input and electromagnetic power 7.6. How to obtain zero d-axis current Iad = 0 7.7. Influence of d-axis current on the power factor 7.8. Vector control of PM synchronous motors 7.9. Starting 7.9.1. Asynchronous starting 7.9.2. Starting by means of an auxiliary motor 7.9.3. Frequency-change starting 7.10. Comparison of PM synchronous motors with induction motors Summary 8. AXIAL AND TRANSVERSE FLUX MOTORS 8.1. Axial flux disk motors 8.1.1. Force and torque of axial flux motors 8.1.2. Double-sided motor with internal PM disk rotor 8.1.3. Stator cores of axial flux motors 8.1.4. Main dimensions of axial flux motors 8.1.5. Double-sided axial-flux motors with a single stator 8.1.6. Single-sided motors 8.1.7. Ironless double-sided motors 8.1.8. Multidisk motors 8.2. Transverse flux motors 8.2.1. Principle of operation 8.2.2. EMF and electromagnetic torque 8.2.3. Armature winding resistance 8.2.4. Armature reaction and leakage reactance 8.2.5. Magnetic circuit 8.2.6. Advantages and disadvantages Summary 9. HIGH-SPEED PM BRUSHLESS MACHINES 9.1. Requirements 9.2. Main dimensions 9.3. Mechanical requirements 9.4. Fundamental problems in design 9.5. Stator design 9.6. Rotor design 9.7. Mechanical design 9.8. Thermal issues and cooling technologies 9.9. Directed energy weapon (DEW) Summary Appendix A: Conversion of units A.1. Conversion of units A.1.1. Definitions A.1.2. Conversion A.1.3. Some physical constants Appendix B: Lenz’s law Appendix C: Right-handed cork-screw rule Appendix D: The right-hand grip rule Appendix E: Left-hand and right-hand rules Symbols and Abbreviations References Index