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Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-1
Chapter 6
Thyristor Converters
• Controlled conversion of ac into dc
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-2
Thyristor Converters
• Two-quadrant conversion
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-3
Primitive circuits with thyristors
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-4
Thyristor Triggering
• ICs available
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-5
Full-Bridge Thyristor Converters
• Single-phase and three-phase
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-6
Single-Phase Thyristor Converters
• Two groups with two thyristor each
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-7
1-Phase Thyristor Converter Waveforms
• Assuming zero ac-side inductance
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-8
Average DC Output Voltage
• Assuming zero ac-side inductance
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-9
Input Line-Current Waveforms
• Harmonics, power and reactive power
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-10
1-Phase Thyristor Converter
• Finite ac-side inductance; constant dc output current
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-11
Thyristor Converter Waveforms
• Finite ac-side inductance
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-12
Thyristor Converter: Discontinuous Mode
• This mode can occur in a dc-drive at light loads
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-13
Thyristor Converter Waveforms
• PSpice-based simulation
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-14
Thyristor Converter Waveforms: Discontinuous Conduction Mode
• PSpice-based simulation
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-15
DC Voltage versus Load Current
• Various values of delay angle
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-16
Thyristor Converters: Inverter Mode
• Assuming the ac-side inductance to be zero
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-17
Thyristor Converters: Inverter Mode
• Family of curves at various values of delay angle
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-18
Thyristor Converters: Inverter Mode
• Importance of extinction angle in inverter mode
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-19
Thyristor Converters: Inverter Mode
• Waveforms at start-up
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-20
3-Phase Thyristor Converters
• Two groups of three thyristors each
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-21
3-Phase Thyristor Converter Waveforms
• Zero ac-side inductance; purely dc current
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-22
DC-side voltage waveforms assuming zero ac-side inductance
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-23
Input Line-Current Waveform
• Zero ac-side inductance
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-24
Input line-current waveforms assuming zero ac-side inductance
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-25
Three-Phase Thyristor Converter
• AC-side inductance is included
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-26
Current Commutation Waveforms
• Constant dc-side current
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-27
Input Line-Current Waveform
• Finite ac-side inductance
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-28
Input Line-Current Harmonics
• Finite ac-side inductance
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-29
Input Line-Current Harmonics
• Typical and idealized
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-30
Three-Phase Thyristor Converter
• Realistic load
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-31
Thyristor Converter Waveforms
• Realistic load; continuous-conduction mode
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-32
Thyristor Converter Waveforms
• Realistic load; discontinuous-conduction mode
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-33
Thyristor Inverter
• Constant dc current
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-34
Thyristor Inverter Waveforms
• Finite ac-side inductance
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-35
Thyristor Inverter
• Family of curves at various values of delay angle
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-36
Thyristor Inverter Operation
• Importance of extinction angle
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-37
Thyristor Converters: Voltage Notching
• Importance of external ac-side inductance
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-38
Limits on Notching and Distortion
• Guidelines
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters 6-39
Thyristor Converter Representation
• Functional block diagram
