Electric Motors and Drives: Fundamentals, Types and Applications 5ed

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Electric Motors and
Drives:

Fundamentals, Types and Applications
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Preface
1
Electric motors-The basics
	Introduction
	Producing rotation
		Magnetic field and magnetic flux
		Magnetic flux density
		Force on a conductor
	Magnetic circuits
		Magnetomotive force (m.m.f.)
		Electric circuit analogy
		The air-gap
		Reluctance and air-gap flux densities
		Saturation
		Magnetic circuits in motors
	Torque production
		Magnitude of torque
		The beauty of slotting
	Torque and motor volume
		Specific loadings
		Torque and rotor volume
		Output power-Importance of speed
		Power density (specific output power)
	Energy conversion-Motional e.m.f
		Elementary motor-Stationary conditions
		Power relationships-Conductor moving at constant speed
	Equivalent circuit
		Motoring and generating
	Constant voltage operation
		Behaviour with no mechanical load
		Behaviour with a mechanical load
		Relative magnitudes of V and E, and efficiency
		Analysis of primitive machine-Conclusions
	General properties of electric motors
		Operating temperature and cooling
		Torque per unit volume
		Power per unit volume and efficiency-Importance of speed
		Size effects-Specific torque and efficiency
		Rated voltage
		Short-term overload
	Review questions
2
Power electronic converters for motor drives
	Introduction
		General arrangement of drive
	Voltage control-D.C. output from d.c. supply
		Switching control
		Transistor chopper
		Chopper with inductive load-Overvoltage protection
		Boost converter
	D.C. from a.c.-Controlled rectification
		The thyristor
		Single pulse rectifier
		Single-phase fully-controlled converter-Output voltage and control
			Resistive load
			Inductive (motor) load
		Three-phase fully-controlled converter
		Output voltage range
		Firing circuits
	A.C. from d.c.-Inversion
		Single-phase inverter
		Output voltage control
			Mode A
			Mode B
			Mode C
			Mode D
		Three-phase inverter
		Multi-level inverter
		Braking
		Active front end
	A.C. from a.c.
		The cycloconverter
		The matrix converter
	Inverter switching devices
		Bipolar junction transistor (BJT)
		Metal oxide semiconductor field effect transistor (MOSFET)
		Insulated gate bipolar transistor (IGBT)
	Converter waveforms, acoustic noise, and cooling
		Cooling of switching devices-Thermal resistance
		Arrangement of heatsinks and forced-air cooling
	Review questions
3
D.C. motors
	Introduction
	Torque production
		Function of the commutator
		Operation of the commutator-interpoles
	Motional e.m.f.
		Equivalent circuit
	D.C. motor-steady-state characteristics
		No-load speed
		Performance calculation-example
		Behaviour when loaded
		Base speed and field weakening
		Armature reaction
		Maximum output power
	Transient behaviour
		Dynamic behaviour and time-constants
	Four quadrant operation and regenerative braking
		Full speed regenerative reversal
		Dynamic braking
	Shunt and series motors
		Shunt motor-steady-state operating characteristics
		Series motor-steady-state operating characteristics
		Universal motors
	Self-excited d.c. machine
	Toy motors
	Review questions
4
D.C. motor drives
	Introduction
	Thyristor d.c. drives-general
		Motor operation with converter supply
		Motor current waveforms
		Discontinuous current
		Converter output impedance: Overlap
		Four-quadrant operation and inversion
		Single-converter reversing drives
		Double-converter reversing drives
		Power factor and supply effects
	Control arrangements for d.c. drives
		Current limits and protection
		Torque control
		Speed control
		Overall operating region
		Armature voltage feedback and IR compensation
		Drives without current control
	Chopper-fed d.c. motor drives
		Performance of chopper-fed d.c. motor drives
		Torque-speed characteristics and control arrangements
	D.C. servo drives
		Servo motors
		Position control
	Digitally-controlled drives
	Review questions
5
Induction motors-Rotating field, slip and torque
	Introduction
		Outline of approach
	The rotating magnetic field
		Production of a rotating magnetic field
		Field produced by each phase-winding
		Resultant three-phase field
		Direction of rotation
		Main (air-gap) flux and leakage flux
		Magnitude of rotating flux wave
		Excitation power and VA
		Summary
	Torque production
		Rotor construction
		Slip
		Rotor induced e.m.f. and current
		Torque
		Rotor currents and torque-small slip
		Rotor currents and torque-large slip
		Generating-Negative slip
	Influence of rotor current on flux
		Reduction of flux by rotor current
	Stator current-speed characteristics
	Review questions
6
Induction motor-Operation from 50/60Hz supply
	Introduction
	Methods of starting cage motors
		Direct starting-Problems
		Star/delta (wye/mesh) starter
		Autotransformer starter
		Resistance or reactance starter
		Solid-state soft starting
		Starting using a variable-frequency inverter
	Run-up and stable operating regions
		Harmonic effects-Skewing
		High inertia loads-Overheating
		Steady-state rotor losses and efficiency
		Steady-state stability-Pull-out torque and stalling
	Torque-speed curves-Influence of rotor parameters
		Cage rotor
		Double cage and deep bar rotors
		Starting and run-up of slipring motors
	Influence of supply voltage on torque-speed curve
	Generating
		Generating region
		Self-excited induction generator
		Doubly-fed induction machine for wind power generation
	Braking
		Plug reversal and plug braking
		Injection braking
	Speed control (without varying the stator supply frequency)
		Pole-changing motors
		Voltage control of high-resistance cage motors
		Speed control of wound-rotor motors
		Slip energy recovery
	Power-factor control and energy optimisation
	Single-phase induction motors
		Principle of operation
		Capacitor run motors
		Split-phase motors
		Shaded pole motors
	Power range
		Scaling down-The excitation problem
	Review questions
7
Variable frequency operation of induction motors
	Introduction
	Variable frequency operation
		Steady-state operation-Importance of achieving full flux
		Torque-speed characteristics
		Limitations imposed by the inverter-Constant torque and constant power regions
		Limitations imposed by the motor
		Four quadrant capability
	Practical aspects of inverter-fed drives
		PWM voltage source inverter
		Current source induction motor drives
		Performance of inverter-fed drives
			Open-loop (without speed/position feedback) induction motor drives
			Closed-loop (with speed/position feedback) induction motor drives
			Applications when field orientation or Direct Torque Control cannot be used
	Effect of inverter on the induction motor
		Acoustic noise
		Motor insulation and the impact of long inverter-motor cables
		Losses and impact on motor rating
		Bearing currents
		`Inverter grade induction motors
	Utility supply effects
		Harmonic currents
		Power factor
	Inverter and motor protection
	Review questions
8
Field oriented control of induction motors
	Introduction
	Essential preliminaries
		Space phasor representation of m.m.f. waves
		Transformation of reference frames
		Transient and steady-states in electric circuits
	Circuit modelling of the induction motor
		Coupled circuits, induced EMF, and flux linkage
		Self and mutual inductance
		Obtaining torque from a circuit model
		Finding the rotor currents
	Steady-state torque under current-fed conditions
		Torque vs slip frequency-Constant stator current
		Torque vs slip frequency-Constant rotor flux linkage
		Flux and torque components of stator current
	Dynamic torque control
		Special property of closely-coupled circuits
		Establishing the flux
		Mechanism of torque control
	Implementation of field-oriented control
		PWM controller/vector modulator
		Torque control scheme
		Transient operation
		Acceleration from rest
		Deriving the rotor flux angle
	Direct torque control
		Outline of operation
		Control of stator flux and torque
	Review questions
9
Synchronous, permanent magnet and reluctance motors and drives
	Introduction
	Synchronous motor types
		Excited-rotor motors
		Permanent magnet motors
		Reluctance motors
		Hysteresis motors
	Torque production
		Excited rotor motor
			Torque-Excited rotor motor
		Permanent magnet motor
			Torque-Permanent magnet motor
		Reluctance motor
			Torque-Reluctance motor
		Salient pole synchronous motor
		Salient permanent magnet motor (`PM/Rel motor)
	Utility-fed synchronous motors
		Excited rotor motor
			Phasor diagram and power-factor control
		Permanent magnet motor
		Reluctance motor
		Salient pole motor
		Starting on utility supply
	Variable frequency operation of synchronous motors
		Phasor diagram of PM motor
		Variable speed and load conditions
			Full load (full torque at base speed)
			Full torque at half base speed (half power)
			Field weakening-Operation at half torque, twice base speed (full power)
	Synchronous motor drives
		Introduction
		Excited rotor motor
			The power circuit and basic operation
			Current source inverter (CSI)
			Starting
			Control
		Permanent magnet motor
			The power circuit
			Control
		Reluctance motor
			The power circuit
			Control
		Salient permanent magnet motor
	Performance of permanent magnet motors
		Advantages of PM motors
		Industrial PM motors
		Summary of performance characteristics
		Limits of operation of a brushless PM motor
		Brushless PM generators
	Emerging developments in permanent magnet motors
		Advantages of high pole number
		Segmented core and concentrated windings
		Fractional slot windings
			Example: 10-pole, 3-phase winding in 12 slots
	Review questions
10
Stepping and switched reluctance motors
	Introduction
	Stepping motors
		Open-loop position control
		Generation of step pulses and motor response
		High speed running and ramping
	Principle of motor operation
		Variable reluctance motor
		Hybrid motor
		Summary
	Motor characteristics
		Static torque-displacement curves
		Single-stepping
		Step position error, and holding torque
		Half stepping
		Step division-Mini-stepping
	Steady-state characteristics-Ideal (constant-current) drive
		Requirements of drive
		Pull-out torque under constant-current conditions
	Drive circuits and pull-out torque-speed curves
		Constant voltage drive
		Current-forced drive
		Constant current (chopper) drive
		Resonances and instability
	Transient performance
		Step response
		Starting from rest
		Optimum acceleration and closed-loop control
	Switched reluctance motor drives
		Principle of operation
		Torque prediction and control
		Power converter and overall drive characteristics
	Review questions
11
Motor/drive selection
	Introduction
	Power ratings and capabilities
	Drive characteristics
		Maximum speed and speed range
	Load requirements-torque-speed characteristics
		Constant-torque load
		Inertia matching
		Fan and pump loads
	General application considerations
		Regenerative operation and braking
		Duty cycle and rating
		Enclosures and cooling
		Dimensional standards
		Supply interaction and harmonics
	Review questions
Appendix: Solutions to review questions
	Chapter 1
	Chapter 2
	Chapter 3
	Chapter 4
	Chapter 5
	Chapter 6
	Chapter 7
	Chapter 8
	Chapter 9
	Chapter 10
	Chapter 11
Further reading
	General motors and drives books - Delving a little deeper
	Control and modelling
	Practical aspects of design and application of motors and drives
	Reliability
	Synchronous reluctance and permanent magnet motors
	Energy efficient electric motors
	Power semiconductor devices
Index
	A
	B
	C
	D
	E
	F
	G
	H
	I
	K
	L
	M
	N
	O
	P
	Q
	R
	S
	T
	U
	V
	W
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