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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 1 Introduction 1-2
Power Electronic Systems
• Block diagram
• Role of Power Electronics
• Reasons for growth
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 1 Introduction 1-3
Linear Power Supply
• Series transistor as an adjustable resistor
• Low Efficiency
• Heavy and bulky
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 1 Introduction 1-4
Switch-Mode Power Supply
• Transistor as a switch• High Efficiency
• High-Frequency Transformer
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Chapter 1 Introduction 1-5
Basic Principle of Switch-Mode Synthesis
• Constant switching frequency• pulse width controls the average
• L-C filters the ripple
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 1 Introduction 1-6
Application in Adjustable Speed Drives
• Conventional drive wastes energy across the throttling
valve to adjust flow rate
• Using power electronics, motor-pump speed is adjusted
efficiently to deliver the required flow rate
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Chapter 1 Introduction 1-7
Scope and Applications
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 1 Introduction 1-8
Power Processor as a Combination of
Converters
• Most practical topologies require an energy
storage element, which also decouples the input
and the output side converters
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 1 Introduction 1-9
Power Flow through Converters
• Converter is a general term
• An ac/dc converter is shown here• Rectifier Mode of operation when power from ac to dc
• Inverter Mode of operation when power from ac to dc
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 1 Introduction 1-10
AC Motor Drive
• Converter 1 rectifies line-frequency ac into dc
• Capacitor acts as a filter; stores energy; decouples• Converter 2 synthesizes low-frequency ac to motor
• Polarity of dc-bus voltage remains unchanged
– ideally suited for transistors of converter 2
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 1 Introduction 1-11
Matrix Converter
• Very general structure
• Would benefit from bi-directional and bi-polarity switches
• Being considered for use in specific applications
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Copyright © 2003by John Wiley & Sons, Inc. Chapter 1 Introduction 1-12
Interdisciplinary Nature of Power Electronics
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Copyright © 2003by John Wiley & Sons, Inc. Chapter 2 Power SemiconductorSwitches: An Overview2-1
Chapter 2 Overview of Power
Semiconductor Devices
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Copyright © 2003by John Wiley & Sons, Inc. Chapter 2 Power SemiconductorSwitches: An Overview2-2
Diodes
• On and off states controlled by the power circuit
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Copyright © 2003by John Wiley & Sons, Inc. Chapter 2 Power SemiconductorSwitches: An Overview2-4
Thyristors
• Semi-controlled device
• Latches ON by a gate-current pulse if forward biased
• Turns-off if current tries to reverse
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Copyright © 2003by John Wiley & Sons, Inc. Chapter 2 Power SemiconductorSwitches: An Overview 2-6
Generic Switch Symbol
• Idealized switch symbol
• When on, current can flow only in the direction of the arrow
• Instantaneous switching from one state to the other
• Zero voltage drop in on-state
• Infinite voltage and current handling capabilities
Switching Characteristics (linearized)
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Copyright © 2003by John Wiley & Sons, Inc. Chapter 2 Power SemiconductorSwitches: An Overview 2-7
Switching Characteristics (linearized)
Switching Power Loss is
proportional to:
• switching frequency• turn-on and turn-off times
Bi l J ti T i t (BJT)
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Copyright © 2003by John Wiley & Sons, Inc. Chapter 2 Power SemiconductorSwitches: An Overview 2-8
Bipolar Junction Transistors (BJT)
• Used commonly in the past• Now used in specific applications
• Replaced by MOSFETs and IGBTs
V i C fi ti f BJT
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Copyright © 2003by John Wiley & Sons, Inc. Chapter 2 Power SemiconductorSwitches: An Overview 2-9
Various Configurations of BJTs
MOSFET
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Copyright © 2003by John Wiley & Sons, Inc. Chapter 2 Power SemiconductorSwitches: An Overview 2-10
MOSFETs
• Easy to control by the gate• Optimal for low-voltage operation at high switching frequencies
• On-state resistance a concern at higher voltage ratings
Gate Turn Off Thyristors (GTO)
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Copyright © 2003by John Wiley & Sons, Inc. Chapter 2 Power SemiconductorSwitches: An Overview 2-11
Gate-Turn-Off Thyristors (GTO)
• Slow switching speeds
• Used at very high power levels
• Require elaborate gate control circuitry
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IGBT
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Copyright © 2003by John Wiley & Sons, Inc. Chapter 2 Power SemiconductorSwitches: An Overview 2-13
IGBT
MCT
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Copyright © 2003by John Wiley & Sons, Inc. Chapter 2 Power SemiconductorSwitches: An Overview 2-14
MCT
Comparison of Controllable Switches
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 2 Power SemiconductorSwitches: An Overview 2-15
Comparison of Controllable Switches
Summary of Device Capabilities
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 2 Power SemiconductorSwitches: An Overview 2-16
Summary of Device Capabilities
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 3 Basic Electrical andMagnetic Circuit Concepts 3-1
Chapter 3
Review of Basic Electrical andMagnetic Circuit Concepts
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Chapter 3 Basic Electrical andMagnetic Circuit Concepts 3-3
Sinusoidal Steady State
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 3 Basic Electrical andMagnetic Circuit Concepts 3-4
Three-Phase Circuit
Steady State in Power Electronics
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Copyright © 2003
by John Wiley & Sons, Inc.Chapter 3 Basic Electrical and
Magnetic Circuit Concepts 3-5
Steady State in Power Electronics
F i A l i
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Copyright © 2003
by John Wiley & Sons, Inc.Chapter 3 Basic Electrical and
Magnetic Circuit Concepts 3-6
Fourier Analysis
Di t ti i th I t C t
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Copyright © 2003
by John Wiley & Sons, Inc.Chapter 3 Basic Electrical and
Magnetic Circuit Concepts 3-7
Distortion in the Input Current
• Voltage is assumed to be sinusoidal• Subscript “1” refers to the fundamental
• The angle is between the voltage and the current fundamental
Phasor Representation
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Copyright © 2003
by John Wiley & Sons, Inc.Chapter 3 Basic Electrical and
Magnetic Circuit Concepts 3-8
Phasor Representation
Response of L and C
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Copyright © 2003
by John Wiley & Sons, Inc.Chapter 3 Basic Electrical and
Magnetic Circuit Concepts 3-9
Response of L and C
Inductor Voltage and Current in
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 3 Basic Electrical and
Magnetic Circuit Concepts 3-10
Inductor Voltage and Current in
Steady State
• Volt-seconds over T equal zero.
Capacitor Voltage and Current
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 3 Basic Electrical and
Magnetic Circuit Concepts 3-11
Capacitor Voltage and Current
in Steady State
• Amp-seconds
over T equal zero.
Ampere’s Law
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 3 Basic Electrical and
Magnetic Circuit Concepts 3-12
pe e s a
• Direction of magnetic field due to currents
• Ampere’s Law: Magnetic field along a path
Direction of Magnetic Field
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 3 Basic Electrical and
Magnetic Circuit Concepts 3-13
g
B-H Relationship; Saturation
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 3 Basic Electrical and
Magnetic Circuit Concepts 3-14
p;
• Definition of permeability
Continuity of Flux Lines
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 3 Basic Electrical and
Magnetic Circuit Concepts 3-15
y
1 2 3 0φ φ φ+ + =
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Analogy between Electrical and
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Copyright © 2003
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Chapter 3 Basic Electrical and
Magnetic Circuit Concepts 3-17
Magnetic Variables
Analogy between Equations in
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 3 Basic Electrical and
Magnetic Circuit Concepts3-18
Electrical and Magnetic Circuits
Magnetic Circuit and its
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by John Wiley & Sons, Inc.
Chapter 3 Basic Electrical and
Magnetic Circuit Concepts3-19
Electrical Analog
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Inductance L
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 3 Basic Electrical and
Magnetic Circuit Concepts3-21
• Inductance relates flux-linkage to current
Analysis of a Transformer
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 3 Basic Electrical and
Magnetic Circuit Concepts3-22
Transformer Equivalent Circuit
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 3 Basic Electrical and
Magnetic Circuit Concepts3-23
Including the Core Losses
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 3 Basic Electrical and
Magnetic Circuit Concepts3-24
Transformer Core
Characteristic
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 3 Basic Electrical and
Magnetic Circuit Concepts3-25
Characteristic
Chapter 4
Computer Simulation
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 4 Computer Simulation of Power
Electronic Converters & Systems4-1
Computer Simulation
System to be Simulated
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 4 Computer Simulation of Power
Electronic Converters & Systems4-2
y
• Challenges in modeling power electronic systems
Large-Signal System Simulation
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 4 Computer Simulation of Power
Electronic Converters & Systems4-3
• Simplest component models
Small-Signal Linearized Model for
Controller Design
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 4 Computer Simulation of Power
Electronic Converters & Systems
4-4
Controller Design
• System linearized around the steady-state point
Closed-Loop Operation: Large Disturbances
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 4 Computer Simulation of Power
Electronic Converters & Systems
4-5
• Simplest component models
• Nonlinearities, Limits, etc. are included
Modeling of Switching Operation
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 4 Computer Simulation of Power
Electronic Converters & Systems
4-6
• Detailed device models
• Just a few switching cycles are studied
Modeling of a Simple Converter
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 4 Computer Simulation of Power
Electronic Converters & Systems
4-7
• Input voltage takes on two discrete values
Trapezoidal Method of Integration
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 4 Computer Simulation of Power
Electronic Converters & Systems
4-8
• The area shown above represents the integral
A Simple Example
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 4 Computer Simulation of Power
Electronic Converters & Systems
4-9
• The input voltage takes on two discrete values
Modeling using PSpice
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 4 Computer Simulation of Power
Electronic Converters & Systems
4-10
• Schematic approach
is far superior
PSpice-based Simulation
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 4 Computer Simulation of Power
Electronic Converters & Systems
4-11
• Simulation results
Simulation using MATLAB
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Copyright © 2003
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Chapter 4 Computer Simulation of Power
Electronic Converters & Systems
4-12
MATLAB-based Simulation
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 4 Computer Simulation of Power
Electronic Converters & Systems
4-13
• Simulation results
Chapter 5
Diode Rectifiers
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency Diode
Rectifiers
5-1
Diode Rectifier Block Diagram
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency Diode
Rectifiers
5-2
• Uncontrolled utility interface (ac to dc)
A Simple Circuit
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency Diode
Rectifiers
5-3
• Resistive load
A Simple Circuit (R-L Load)
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency Diode
Rectifiers
5-4
• Current continues to flows for a while even after the input
voltage has gone negative
A Simple Circuit (Load has a dc back-emf)
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency Diode
Rectifiers
5-5
• Current begins to flow when the input voltage exceeds the dc back-emf
• Current continues to flows for a while even after the input voltage has
gone below the dc back-emf
Single-Phase Diode Rectifier Bridge
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency Diode
Rectifiers
5-6
• Large capacitor at the dc output for filtering and energy
storage
Diode-Rectifier Bridge Analysis
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Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency Diode
Rectifiers
5-7
• Two simple (idealized) cases to begin with
Redrawing Diode-Rectifier Bridge
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency Diode
Rectifiers
5-8
• Two groups, each with two diodes
Waveforms with a
purely resistive load
and a purely dc current
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency Diode
Rectifiers
5-9
at the output
• In both cases, the dc-side
voltage waveform is the same
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Diode-Rectifier Bridge Analysis with AC-
Side Inductance
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency Diode
Rectifiers
5-11
• Output current is assumed to be purely dc
Understanding Current Commutation
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency Diode
Rectifiers
5-12
• Assuming inductance in this circuit to be zero
Understanding Current Commutation (cont.)
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency DiodeRectifiers
5-13
• Inductance in this circuit is included
Current Commutation Waveforms
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency DiodeRectifiers
5-14
• Shows the volt-seconds needed to commutate current
Current Commutation in Full-Bridge Rectifier
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency DiodeRectifiers
5-15
• Shows the necessary volt-seconds
Understanding Current Commutation
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency DiodeRectifiers
5-16
• Note the current loops for analysis
Rectifier with a dc-
side voltage
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Chapter 5 Line-Frequency DiodeRectifiers
5-17
DC-Side Voltage and Current Relationship
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Chapter 5 Line-Frequency DiodeRectifiers
5-18
• Zero current corresponds to dc voltage equal to the peak of
the input ac voltage
Effect of DC-Side Current on
THD, PF and DPF
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency DiodeRectifiers
5-19
• Very high THD at low current values
Crest Factor versus the Current Loading
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency DiodeRectifiers
5-20
• The Crest Factor is very high at low values of current
Diode-Rectifier with a Capacitor Filter
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency DiodeRectifiers
5-21
• Power electronics load is represented by an equivalent load
resistance
Diode Rectifier Bridge
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency DiodeRectifiers
5-22
• Equivalent circuit for analysis on one-half cycle basis
Diode-Bridge Rectifier: Waveforms
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Chapter 5 Line-Frequency DiodeRectifiers
5-23
• Analysis using MATLAB
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Line-Voltage Distortion
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency DiodeRectifiers
5-26
• PCC is the point of common coupling
Line-Voltage Distortion
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Chapter 5 Line-Frequency DiodeRectifiers
5-27
• Distortion in voltage supplied to other loads
Voltage Doubler Rectifier
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Chapter 5 Line-Frequency DiodeRectifiers
5-28
• In 115-V position, one capacitor at-a-time is charged from the
input.
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Current in A Three-Phase, Four-Wire
System
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Chapter 5 Line-Frequency DiodeRectifiers
5-30
• The current in the neutral wire can be very high
Three-Phase, Full-Bridge Rectifier
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency DiodeRectifiers
5-31
• Commonly used
Three-Phase, Full-Bridge Rectifier: Redrawn
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Chapter 5 Line-Frequency DiodeRectifiers
5-32
• Two groups with three diodes each
Three-Phase, Full-Bridge Rectifier Waveforms
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Chapter 5 Line-Frequency DiodeRectifiers
5-33
• Output current is
assumed to be dc
Three-Phase, Full-Bridge Rectifier: Input
Line-Current
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency DiodeRectifiers
5-34
• Assuming output current to be purely dc and zero ac-side
inductance
Three-Phase, Full-Bridge Rectifier
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Chapter 5 Line-Frequency DiodeRectifiers
5-35
• Including the ac-side inductance
3-Phase Rectifier: Current Commutation
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Chapter 5 Line-Frequency DiodeRectifiers
5-36
• output
current is
assumed to bepurely dc
Rectifier with a Large Filter Capacitor
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Chapter 5 Line-Frequency DiodeRectifiers
5-37
• Output voltage is assumed to be purely dc
Three-Phase, Full-Bridge Rectifier
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency DiodeRectifiers
5-38
• THD, PF and DPF as functions of load current
Crest Factor versus the Current Loading
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Chapter 5 Line-Frequency DiodeRectifiers
5-39
• The Crest Factor is very high at low values of current
Three-Phase Rectifier Waveforms
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 5 Line-Frequency DiodeRectifiers
5-40
• PSpice-based analysis
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Primitive circuits
with thyristors
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Chapter 6 Thyristor Converters 6-3
Thyristor Triggering
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Chapter 6 Thyristor Converters 6-4
• ICs available
Full-Bridge Thyristor Converters
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Chapter 6 Thyristor Converters 6-5
• Single-phase and three-phase
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1-Phase Thyristor Converter Waveforms
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Chapter 6 Thyristor Converters 6-7
• Assuming zero ac-side inductance
Average DC Output Voltage
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Chapter 6 Thyristor Converters 6-8
• Assuming zero ac-side inductance
Input Line-Current Waveforms
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Chapter 6 Thyristor Converters 6-9
• Harmonics, power and reactive power
1-Phase Thyristor Converter
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Chapter 6 Thyristor Converters 6-10
• Finite ac-side inductance; constant dc output
current
Thyristor Converter Waveforms
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Chapter 6 Thyristor Converters 6-11
• Finite ac-side inductance
Thyristor Converter: Discontinuous Mode
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Chapter 6 Thyristor Converters 6-12
• This mode can occur in a dc-drive at light loads
Thyristor Converter Waveforms
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Chapter 6 Thyristor Converters 6-13
• PSpice-based simulation
Thyristor Converter Waveforms:
Discontinuous Conduction Mode
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Chapter 6 Thyristor Converters 6-14
• PSpice-based simulation
DC Voltage versus Load Current
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Chapter 6 Thyristor Converters 6-15
• Various values of delay angle
Thyristor Converters: Inverter Mode
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Chapter 6 Thyristor Converters 6-16
• Assuming the ac-side inductance to be zero
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Thyristor Converters: Inverter Mode
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Chapter 6 Thyristor Converters 6-19
• Waveforms at start-up
3-Phase Thyristor Converters
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Chapter 6 Thyristor Converters 6-20
• Two groups of three thyristors each
3-Phase Thyristor Converter Waveforms
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Chapter 6 Thyristor Converters 6-21
• Zero ac-side inductance; purely dc current
DC-side voltage
waveforms
assuming zero ac-
side inductance
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Chapter 6 Thyristor Converters 6-22
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Input line-current
waveforms
assuming zero ac-
side inductance
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Chapter 6 Thyristor Converters 6-24
Three-Phase Thyristor Converter
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Chapter 6 Thyristor Converters 6-25
• AC-side inductance is included
Current Commutation Waveforms
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Chapter 6 Thyristor Converters 6-26
• Constant dc-side current
Input Line-Current Waveform
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Chapter 6 Thyristor Converters 6-27
• Finite ac-side inductance
Input Line-Current Harmonics
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Chapter 6 Thyristor Converters 6-28
• Finite ac-side inductance
Input Line-Current Harmonics
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Chapter 6 Thyristor Converters 6-29
• Typical and idealized
Three-Phase Thyristor Converter
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Chapter 6 Thyristor Converters 6-30
• Realistic load
Thyristor Converter Waveforms
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Chapter 6 Thyristor Converters 6-31
• Realistic load; continuous-conduction mode
Thyristor Converter Waveforms
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Chapter 6 Thyristor Converters 6-32
• Realistic load; discontinuous-conduction mode
Thyristor Inverter
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Chapter 6 Thyristor Converters 6-33
• Constant dc current
Thyristor Inverter Waveforms
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Chapter 6 Thyristor Converters 6-34
• Finite ac-side inductance
Thyristor Inverter
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Chapter 6 Thyristor Converters 6-35
• Family of curves at various values of delay angle
Thyristor Inverter Operation
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Chapter 6 Thyristor Converters 6-36
• Importance of extinction angle
Thyristor Converters: Voltage Notching
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Chapter 6 Thyristor Converters 6-37
• Importance of external ac-side inductance
Limits on Notching and Distortion
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Chapter 6 Thyristor Converters 6-38
• Guidelines
Thyristor Converter Representation
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Chapter 6 Thyristor Converters 6-39
• Functional block diagram
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Block Diagram of DC-DC Converters
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Chapter 7 DC-DC Switch-ModeConverters
7-2
• Functional block diagram
Stepping Down a DC Voltage
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Chapter 7 DC-DC Switch-ModeConverters
7-3
• A simple approach that shows the evolution
Pulse-Width Modulation inDC-DC Converters
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Chapter 7 DC-DC Switch-ModeConverters
7-4
• Role of PWM
Step-Down DC-DC Converter
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Chapter 7 DC-DC Switch-ModeConverters
7-5
• Pulsating input to
the low-pass filter
Step-Down DC-DC Converter: Waveforms
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Chapter 7 DC-DC Switch-ModeConverters
7-6
• Steady state; inductor current flows continuously
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Step-Down DC-DC Converter:Discontinuous Conduction Mode
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Chapter 7 DC-DC Switch-ModeConverters
7-8
• Steady state; inductor current discontinuous
Step-Down DC-DC Converter: Limits of
Cont./Discont. Conduction
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Chapter 7 DC-DC Switch-ModeConverters
7-9
• The duty-ratio of 0.5 has the highest value of the
critical current
Step-Down DC-DC Converter: Limits of
Cont./Discont. Conduction
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Chapter 7 DC-DC Switch-ModeConverters
7-10
• Output voltage is kept constant
Step-Down Conv.: Output Voltage Ripple
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Chapter 7 DC-DC Switch-ModeConverters
7-11
• ESR is assumed to be zero
Step-Up DC-DC Converter
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Chapter 7 DC-DC Switch-ModeConverters
7-12
• Output voltage must be greater than the input
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Step-Up DC-DC Converter: Limits of
Cont./Discont. Conduction
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Chapter 7 DC-DC Switch-ModeConverters
7-14
• The output voltage is held constant
Step-Up DC-DC Converter: Discont.
Conduction
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Chapter 7 DC-DC Switch-ModeConverters
7-15
• Occurs at light loads
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Step-Up DC-DC Converter: Effect of
Parasitics
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Chapter 7 DC-DC Switch-ModeConverters
7-17
• The duty-ratio is generally limited before theparasitic effects become significant
Step-Up DC-DC Converter Output Ripple
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Chapter 7 DC-DC Switch-ModeConverters
7-18
• ESR is assumed to be zero
Step-Down/Up DC-DC Converter
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Chapter 7 DC-DC Switch-ModeConverters
7-19
• The output voltage can be higher or lower thanthe input voltage
Step-Up DC-DC Converter: Waveforms
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Chapter 7 DC-DC Switch-ModeConverters
7-20
• Continuation conduction mode
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Step-Up DC-DC Converter:
Discontinuous Conduction Mode
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Chapter 7 DC-DC Switch-ModeConverters
7-22
• This occurs at light loads
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Step-Up DC-DC Converter: Effect of
Parasitics
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Chapter 7 DC-DC Switch-ModeConverters
7-24
• The duty-ratio is limited to avoid these parasiticeffects from becoming significant
Step-Up DC-DC Converter:Output Voltage Ripple
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Chapter 7 DC-DC Switch-ModeConverters
7-25
• ESR is assumed to be zero
Cuk DC-DC Converter
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Chapter 7 DC-DC Switch-ModeConverters
7-26
• The output voltage can be higher or lower than
the input voltage
Cuk DC-DC Converter: Waveforms
• The capacitor
voltage is assumed
constant
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Chapter 7 DC-DC Switch-ModeConverters
7-27
Converter for DC-Motor Drives
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Chapter 7 DC-DC Switch-ModeConverters
7-28
• Four quadrant operation is possible
Converter Waveforms
• Bi-polar voltage switching
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Chapter 7 DC-DC Switch-ModeConverters
7-29
Converter Waveforms
• Uni polar voltage switching
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Chapter 7 DC-DC Switch-ModeConverters
7-30
• Uni-polar voltage switching
Output Ripple in Converters for DC-MotorDrives
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Chapter 7 DC-DC Switch-ModeConverters
7-31
• bi-polar and uni-polar voltage switching
Switch Utilization in DC-DC Converters
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Chapter 7 DC-DC Switch-ModeConverters
7-32
• It varies significantly in various converters
Equivalent Circuits in DC-DC Converters
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Chapter 7 DC-DC Switch-ModeConverters
7-33
• replacing inductors and capacitors by current
and voltage sources, respectively
Reversing the Power Flow in DC-DC Conv.
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Chapter 7 DC-DC Switch-ModeConverters
7-34
• For power flow from right to left, the input
current direction should also reverse
Chapter 8
Switch-Mode DC-AC Inverters
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-1
• converters for ac motor drives anduninterruptible power supplies
Switch-Mode DC-AC Inverter
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-2
• Block diagram of a motor drive where the powerflow is unidirectional
Switch-Mode DC-AC Inverter
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-3
• Block diagram of a motor drive where the powerflow can be bi-directional
Switch-Mode DC-AC Inverter
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-4
• Four quadrants of operation
One Leg of a Switch-Mode DC-AC Inverter
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-5
• The mid-point shown is fictitious
Synthesis of a Sinusoidal Output by PWM
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-6
Details of a Switching Time Period
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-7
• Control voltage can be assumed constant duringa switching time-period
Harmonics in the DC-AC Inverter OutputVoltage
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-8
• Harmonics appear around the carrier frequency
and its multiples
Harmonics due to Over-modulation
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-9
• These are harmonics of the fundamental
frequency
Output voltage Fundamental as a Functionof the Modulation Index
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-10
• Shows the linear and the over-modulationregions; square-wave operation in the limit
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Half-Bridge Inverter
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-12
• Capacitors provide the mid-point
Single-Phase Full-Bridge DC-AC Inverter
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-13
• Consists of two inverter legs
PWM to Synthesize Sinusoidal Output
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-14
• The dotted curve is the desired output; also the
fundamental frequency
Analysis assuming Fictitious Filters
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-15
• Small fictitious filters eliminate the switching-
frequency related ripple
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Output Waveforms:Uni-polar Voltage
Switching
• Harmoniccomponents around
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-17
components around
the switching
frequency are absent
DC-Side Current in a Single-Phase Inverter
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-18
• Uni-polar voltage switching
Sinusoidal Synthesis by Voltage Shift
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-19
• Phase shift allows voltage cancellation tosynthesize a 1-Phase sinusoidal output
Single-Phase Inverter
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-20
• Analysis at the fundamental frequency
Square-Wave and PWM Operation
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-21
• PWM results in much smaller ripple current
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Three-Phase Inverter
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-23
• Three inverter legs; capacitor mid-point isfictitious
Three-Phase
PWM
Waveforms
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-24
Three-Phase Inverter Harmonics
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-25
Three-Phase Inverter Output
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-26
• Linear and over-modulation ranges
Three-Phase Inverter: Square-Wave Mode
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-27
• Harmonics are of the fundamental frequency
Three-Phase Inverter: FundamentalFrequency
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-28
• Analysis at the fundamental frequency can bedone using phasors
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DC-Side Current in a Three-Phase Inverter
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-30
• The current consists of a dc component and the
switching-frequency related harmonics
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PWM Operation
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-32
• devices conducting are indicated
Short-Circuit States in PWM Operation
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-33
• top group or the bottom group results in short
circuiting three terminals
Effect of BlankingTime
• Results in
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-34
Results in
nonlinearity
Effect of Blanking Time
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-35
• Voltage jump when the current reverses direction
Effect of Blanking Time
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-36
• Effect on the output voltage
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Tolerance-Band Current Control
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-38
• Results in a variable frequency operation
Fixed-Frequency Operation
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-39
• Better control is possible using dq analysis
Transition from Inverter to Rectifier Mode
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-40
• Can analyze based on the fundamental-
frequency components
Summary of DC-AC Inverters
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Chapter 8 Switch-Mode DC-Sinusoidal AC Inverters
8-41
• Functional representation in a block-diagram form
Chapter 9Zero-Voltage or Zero-Current Switchings
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Chapter 9 Resonant Converters 9-1
• converters for soft switching
One Inverter Leg
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Chapter 9 Resonant Converters 9-2
• The output current can be positive or negative
Hard Switching Waveforms
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Chapter 9 Resonant Converters 9-3
• The output current can be positive or negative
Turn-on and Turn-off Snubbers
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Chapter 9 Resonant Converters 9-4
• Turn-off snubbers are used
Switching Trajectories
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Chapter 9 Resonant Converters 9-5
• Comparison of Hard versus soft switching
Undamped Series-Resonant Circuit
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Chapter 9 Resonant Converters 9-6
• The waveforms shown include initial conditions
Series-Resonant Circuit withCapacitor-Parallel Load
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Chapter 9 Resonant Converters 9-7
• The waveforms shown include initial conditions
Impedance of a Series-Resonant Circuit
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Chapter 9 Resonant Converters 9-8
• The impedance is capacitive below theresonance frequency
Undamped Parallel-Resonant Circuit
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Chapter 9 Resonant Converters 9-9
• Excited by a current source
Impedance of a Parallel-Resonant Circuit
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Chapter 9 Resonant Converters 9-10
• The impedance is inductive at below the
resonant frequency
Series Load Resonant (SLR) Converter
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Chapter 9 Resonant Converters 9-11
• The transformer is ignored in this equivalentcircuit
SLR Converter Waveforms
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Chapter 9 Resonant Converters 9-12
• The operating frequency is below one-half theresonance frequency
SLR Converter Waveforms
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Chapter 9 Resonant Converters 9-13
• The operating frequency is in between one-half theresonance frequency and the resonance frequency
SLR Converter Waveforms
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Chapter 9 Resonant Converters 9-14
• The operating frequency is above the resonancefrequency
Lossless Snubbers in SLR Converters
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Chapter 9 Resonant Converters 9-15
• The operating frequency is above the resonancefrequency
SLR Converter Characteristics
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Chapter 9 Resonant Converters 9-16
• Output Current as a function of operatingfrequency for various values of the output voltage
SLR Converter Control
• The operating frequency is varied to regulate
the output voltage
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Chapter 9 Resonant Converters 9-17
Parallel Load Resonant (PLR) Converter
• The transformer is ignored in this equivalent
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Chapter 9 Resonant Converters 9-18
• The transformer is ignored in this equivalent
circuit
PLR Converter Waveforms
• The current is in a discontinuous conduction
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Chapter 9 Resonant Converters 9-19
• The current is in a discontinuous conduction
mode
PLR Converter Waveforms
Th ti f i b l th
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Chapter 9 Resonant Converters 9-20
• The operating frequency is below the resonance
frequency
PLR Converter Waveforms
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Chapter 9 Resonant Converters 9-21
• The operating frequency is above the resonancefrequency
PLR Converter Characteristics
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Chapter 9 Resonant Converters 9-22
• Output voltage as a function of operatingfrequency for various values of the output current
Hybrid-Resonant DC-DC Converter
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Chapter 9 Resonant Converters 9-23
• Combination of series and parallel resonance
Parallel-Resonant Current-Source Converter
• Basic circuit to illustrate the operating principle
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Chapter 9 Resonant Converters 9-24
at the fundamental frequency
Parallel-Resonant Current-Source Converter
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Chapter 9 Resonant Converters 9-25
• Using thyristors; for induction heating
Class-E Converters
Optimum mode
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Chapter 9 Resonant Converters 9-26
Class-E Converters
Non-Optimum
mode
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Chapter 9 Resonant Converters 9-27
Resonant Switch Converters
Classifications
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Chapter 9 Resonant Converters 9-28
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ZCS Resonant-Switch Converter
• Waveforms; voltage is regulated by varying the
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-30
switching frequency
ZCS Resonant-Switch Converter
• A practical circuit
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Chapter 9 Resonant Converters 9-31
ZVS Resonant-Switch Converter
• Serious limitations
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Chapter 9 Resonant Converters 9-32
ZVS Resonant-Switch Converter
• Waveforms
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Chapter 9 Resonant Converters 9-33
MOSFET Internal Capacitances
• These capacitances affect the MOSFET switching
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Chapter 9 Resonant Converters 9-34
ZVS-CV DC-DC Converter
Th i d t t t di ti
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Chapter 9 Resonant Converters 9-35
• The inductor current must reverse directionduring each switching cycle
ZVS-CV DC-DC Converter
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Chapter 9 Resonant Converters 9-36
• One transition is shown
ZVS-CV Principle Applied to DC-AC Inverters
• Very large ripple in the output current
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Chapter 9 Resonant Converters 9-37
Three-Phase ZVS-CV DC-AC Inverter
• Very large ripple in the output current
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Chapter 9 Resonant Converters 9-38
Output Regulation by Voltage Control
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Chapter 9 Resonant Converters 9-39
• Each pole operates at nearly 50% duty-ratio
ZVS-CV with Voltage Cancellation
• Commonly used
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Chapter 9 Resonant Converters 9-40
Resonant DC-Link Inverter
• The dc-link voltageis made to oscillate
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Chapter 9 Resonant Converters 9-41
Three-Phase Resonant DC-Link Inverter
• Modifications have been proposed
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Chapter 9 Resonant Converters 9-42
High-Frequency-Link Inverter
• Basic principle for selecting integral half-cycles of the
high-frequency ac input
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Chapter 9 Resonant Converters 9-43
high frequency ac input
High-Frequency-Link Inverter
• Low-frequency ac output is synthesized by selecting
integral half-cycles of the high-frequency ac input
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Chapter 9 Resonant Converters 9-44
integral half cycles of the high frequency ac input
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Chapter 10
Switching DC Power Supplies
• One of the most important applications of power
electronics
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Chapter 10 SwitchingDC Power Supplies
10-1
e ect o cs
Linear Power Supplies
• Very poor efficiency and large weight and size
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Chapter 10 SwitchingDC Power Supplies
10-2
y p y g g
Switching DC Power Supply: Block Diagram
• High efficiency and small weight and size
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Chapter 10 SwitchingDC Power Supplies
10-3
g y g
Switching DC Power Supply: Multiple
Outputs
• In most applications, several dc voltages arerequired possibly electrically isolated from each other
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Chapter 10 SwitchingDC Power Supplies
10-4
pp grequired, possibly electrically isolated from each other
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PWM to Regulate Output
• Basic principle is the same as discussed in Chapter 8
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Chapter 10 SwitchingDC Power Supplies
10-6
Flyback Converter
• Derived from buck-boost; very power at small power
(> 50 W ) power levels
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Chapter 10 SwitchingDC Power Supplies
10-7
Flyback Converter
• Switch on and off states (assuming incomplete core
demagnetization)
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Chapter 10 SwitchingDC Power Supplies
10-8
Flyback Converter
• Switching waveforms (assuming incomplete coredemagnetization)
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Chapter 10 SwitchingDC Power Supplies
10-9
g )
Other Flyback Converter Topologies
• Not commonly used
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Chapter 10 SwitchingDC Power Supplies
10-10
C i ht © 2003
Forward Converter
• Derived from Buck; idealized to assume that the
transformer is ideal (not possible in practice)
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Chapter 10 SwitchingDC Power Supplies
10-11
C i ht © 2003 Ch t 10 S it hi
Forward Converter:
in Practice
• Switching waveforms (assuming
incomplete core demagnetization)
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Chapter 10 SwitchingDC Power Supplies
10-12
Copyright © 2003 Ch t 10 S it hi
Forward Converter: Other Possible Topologies
• Two-switch Forward converter is very commonly used
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Chapter 10 SwitchingDC Power Supplies
10-13
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Copyright © 2003 Chapter 10 Switching 10 15
Half-Bridge Converter
• Derived from Buck
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Chapter 10 SwitchingDC Power Supplies
10-15
Copyright © 2003 Chapter 10 Switching 10 16
Full-Bridge Converter
• Used at higher power levels (> 0.5kW
)
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Chapter 10 SwitchingDC Power Supplies
10-16
Copyright © 2003 Chapter 10 Switching 10 17
Current-Source Converter
• More rugged (no shoot-through) but both switches
must not be open simultaneously
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py gby John Wiley & Sons, Inc.
Chapter 10 SwitchingDC Power Supplies
10-17
Copyright © 2003 Chapter 10 Switching 10 18
Ferrite Core Material
• Several materials to choose from based on applications
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y gby John Wiley & Sons, Inc.
p gDC Power Supplies
10-18
Copyright © 2003 Chapter 10 Switching 10-19
Core Utilization in Various Converter
Topologies
• At high switching frequencies, core losses limitexcursion of flux density
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Chapter 10 Switching 10-20
Control to Regulate Voltage Output
• Linearized representation of the feedback controlsystem
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Copyright © 2003b J h Wil & S I
Chapter 10 SwitchingDC P S li
10-21
Forward Converter: An Example
• The switch and the diode are assumed to be ideal
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Copyright © 2003by John Wiley & Sons Inc
Chapter 10 SwitchingDC P S li
10-22
Forward Converter:Transfer Function Plots
• Example
considered earlier
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Copyright © 2003by John Wiley & Sons Inc
Chapter 10 SwitchingDC Power Supplies
10-23
Flyback Converter:Transfer Function Plots
• An example
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Copyright © 2003by John Wiley & Sons Inc
Chapter 10 SwitchingDC Power Supplies
10-24
Linearizing the PWM Block
• The transfer function is essentially a constant with
zero phase shift
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Copyright © 2003by John Wiley & Sons, Inc.
Chapter 10 SwitchingDC Power Supplies
10-25
Gain of the PWM IC
• It is slope of the characteristic
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by John Wiley & Sons, Inc. DC Power Supplies
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Chapter 10 SwitchingDC Power Supplies
10-27
A General Amplifier for Error Compensation
• Can be implemented using a single op-amp
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y y pp
Copyright © 2003by John Wiley & Sons, Inc.
Chapter 10 SwitchingDC Power Supplies
10-28
Type-2 Error Amplifier
• Shows phase boost at the crossover frequency
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Chapter 10 SwitchingDC Power Supplies
10-29
Voltage Feed-Forward
• Makes converter immune from input voltage
variations
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Chapter 10 SwitchingDC Power Supplies
10-30
Voltage versus Current Mode Control
• Regulating the output voltage is the objective in both
modes of control
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Chapter 10 SwitchingDC Power Supplies
10-32
Peak Current Mode Control
• Slope compensation is needed
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Chapter 10 SwitchingDC Power Supplies
10-33
A Typical PWM Control IC
• Many safety control
functions are built in
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Chapter 10 SwitchingDC Power Supplies
10-34
Current Limiting
• Two options are shown
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Chapter 10 SwitchingDC Power Supplies
10-35
Implementing
ElectricalIsolation in the
Feedback Loop
• Two ways are shown
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