9-1 copyright © 2003 by john wiley & sons, inc. chapter 9 resonant converters chapter 9...
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Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-1
Chapter 9
Zero-Voltage or Zero-Current Switchings
• converters for soft switching
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-2
One Inverter Leg
• The output current can be positive or negative
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-3
Hard Switching Waveforms
• The output current can be positive or negative
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-4
Turn-on and Turn-off Snubbers
• Turn-off snubbers are used
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-5
Switching Trajectories
• Comparison of Hard versus soft switching
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-6
Undamped Series-Resonant Circuit
• The waveforms shown include initial conditions
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-7
Series-Resonant Circuit with Capacitor-Parallel Load
• The waveforms shown include initial conditions
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-8
Impedance of a Series-Resonant Circuit
• The impedance is capacitive below the resonance frequency
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-9
Undamped Parallel-Resonant Circuit
• Excited by a current source
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-10
Impedance of a Parallel-Resonant Circuit
• The impedance is inductive at below the resonant frequency
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-11
Series Load Resonant (SLR) Converter
• The transformer is ignored in this equivalent circuit
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-12
SLR Converter Waveforms
• The operating frequency is below one-half the resonance frequency
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-13
SLR Converter Waveforms
• The operating frequency is in between one-half the resonance frequency and the resonance frequency
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-14
SLR Converter Waveforms
• The operating frequency is above the resonance frequency
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-15
Lossless Snubbers in SLR Converters
• The operating frequency is above the resonance frequency
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-16
SLR Converter Characteristics
• Output Current as a function of operating frequency for various values of the output voltage
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-17
SLR Converter Control
• The operating frequency is varied to regulate the output voltage
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-18
Parallel Load Resonant (PLR) Converter
• The transformer is ignored in this equivalent circuit
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-19
PLR Converter Waveforms
• The current is in a discontinuous conduction mode
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-20
PLR Converter Waveforms
• The operating frequency is below the resonance frequency
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-21
PLR Converter Waveforms
• The operating frequency is above the resonance frequency
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-22
PLR Converter Characteristics
• Output voltage as a function of operating frequency for various values of the output current
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Chapter 9 Resonant Converters 9-23
Hybrid-Resonant DC-DC Converter
• Combination of series and parallel resonance
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-24
Parallel-Resonant Current-Source Converter
• Basic circuit to illustrate the operating principle at the fundamental frequency
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-25
Parallel-Resonant Current-Source Converter
• Using thyristors; for induction heating
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Chapter 9 Resonant Converters 9-26
Class-E Converters
Optimum mode
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Chapter 9 Resonant Converters 9-27
Class-E Converters
Non-Optimum mode
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Chapter 9 Resonant Converters 9-28
Resonant Switch Converters
Classifications
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Chapter 9 Resonant Converters 9-29
ZCS Resonant-Switch Converter
• One possible implementation
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-30
ZCS Resonant-Switch Converter
• Waveforms; voltage is regulated by varying the switching frequency
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Chapter 9 Resonant Converters 9-31
ZCS Resonant-Switch Converter
• A practical circuit
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Chapter 9 Resonant Converters 9-32
ZVS Resonant-Switch Converter
• Serious limitations
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Chapter 9 Resonant Converters 9-33
ZVS Resonant-Switch Converter
• Waveforms
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Chapter 9 Resonant Converters 9-34
MOSFET Internal Capacitances
• These capacitances affect the MOSFET switching
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Chapter 9 Resonant Converters 9-35
ZVS-CV DC-DC Converter
• The inductor current must reverse direction during each switching cycle
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Chapter 9 Resonant Converters 9-36
ZVS-CV DC-DC Converter
• One transition is shown
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Chapter 9 Resonant Converters 9-37
ZVS-CV Principle Applied to DC-AC Inverters
• Very large ripple in the output current
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-38
Three-Phase ZVS-CV DC-AC Inverter
• Very large ripple in the output current
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Chapter 9 Resonant Converters 9-39
Output Regulation by Voltage Control
• Each pole operates at nearly 50% duty-ratio
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Chapter 9 Resonant Converters 9-40
ZVS-CV with Voltage Cancellation
• Commonly used
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Chapter 9 Resonant Converters 9-41
Resonant DC-Link Inverter
• The dc-link voltage is made to oscillate
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Chapter 9 Resonant Converters 9-42
Three-Phase Resonant DC-Link Inverter
• Modifications have been proposed
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Chapter 9 Resonant Converters 9-43
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 9-44
High-Frequency-Link Inverter
• Low-frequency ac output is synthesized by selecting integral half-cycles of the high-frequency ac input
Copyright © 2003 by John Wiley & Sons, Inc.
Chapter 9 Resonant Converters 9-45
High-Frequency-Link Inverter
• Shows how to implement such an inverter
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