7-1 copyright © 2003 by john wiley & sons, inc. chapter 7 dc-dc switch-mode converters chapter...
Post on 20-Dec-2015
245 views
TRANSCRIPT
![Page 1: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/1.jpg)
7-1
Chapter 7
DC-DC Switch-Mode Converters
• dc-dc converters for switch-mode dc power supplies and dc-motor drives
![Page 2: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/2.jpg)
7-2
Block Diagram of DC-DC Converters
• Functional block diagram
![Page 3: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/3.jpg)
7-3
Stepping Down a DC Voltage
• A simple approach that shows the evolution
![Page 4: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/4.jpg)
7-4
Pulse-Width Modulation in DC-DC Converters
• Role of PWM
![Page 5: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/5.jpg)
7-5
Step-Down DC-DC Converter
• Pulsating input to the low-pass filter
![Page 6: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/6.jpg)
7-6
Step-Down DC-DC Converter: Waveforms
• Steady state; inductor current flows continuously
![Page 7: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/7.jpg)
7-7
Step-Down DC-DC Converter: Waveforms at the boundary of Cont./Discont. Conduction
• Critical current below which inductor current becomes discontinuous
![Page 8: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/8.jpg)
7-8
Step-Down DC-DC Converter: Discontinuous Conduction Mode
• Steady state; inductor current discontinuous
![Page 9: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/9.jpg)
7-9
Step-Down DC-DC Converter: Limits of Cont./Discont. Conduction
• The duty-ratio of 0.5 has the highest value of the critical current
![Page 10: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/10.jpg)
7-10
Step-Down DC-DC Converter: Limits of Cont./Discont. Conduction
• Output voltage is kept constant
![Page 11: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/11.jpg)
7-11
Step-Down Conv.: Output Voltage Ripple
• ESR is assumed to be zero
![Page 12: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/12.jpg)
7-12
Step-Up DC-DC Converter
• Output voltage must be greater than the input
![Page 13: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/13.jpg)
7-13
Step-Up DC-DC Converter Waveforms
• Continuous current conduction mode
![Page 14: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/14.jpg)
7-14
Step-Up DC-DC Converter: Limits of Cont./Discont. Conduction
• The output voltage is held constant
![Page 15: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/15.jpg)
7-15
Step-Up DC-DC Converter: Discont. Conduction
• Occurs at light loads
![Page 16: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/16.jpg)
7-16
Step-Up DC-DC Converter: Limits of Cont./Discont. Conduction
• The output voltage is held constant
![Page 17: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/17.jpg)
7-17
Step-Up DC-DC Converter: Effect of Parasitics
• The duty-ratio is generally limited before the parasitic effects become significant
![Page 18: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/18.jpg)
7-18
Step-Up DC-DC Converter Output Ripple
• ESR is assumed to be zero
![Page 19: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/19.jpg)
7-19
Step-Down/Up DC-DC Converter
• The output voltage can be higher or lower than the input voltage
![Page 20: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/20.jpg)
7-20
Step-Up DC-DC Converter: Waveforms
• Continuation conduction mode
![Page 21: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/21.jpg)
7-21
Step-Up DC-DC Converter: Limits of Cont./Discont. Conduction
• The output voltage is held constant
![Page 22: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/22.jpg)
7-22
Step-Up DC-DC Converter: Discontinuous Conduction Mode
• This occurs at light loads
![Page 23: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/23.jpg)
7-23
Step-Up DC-DC Converter: Limits of Cont./Discont. Conduction
• The output voltage is held constant
![Page 24: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/24.jpg)
7-24
Step-Up DC-DC Converter: Effect of Parasitics
• The duty-ratio is limited to avoid these parasitic effects from becoming significant
![Page 25: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/25.jpg)
7-25
Step-Up DC-DC Converter: Output Voltage Ripple
• ESR is assumed to be zero
![Page 26: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/26.jpg)
7-26
Cuk DC-DC Converter
• The output voltage can be higher or lower than the input voltage
![Page 27: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/27.jpg)
7-27
Cuk DC-DC Converter: Waveforms
• The capacitor voltage is assumed constant
![Page 28: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/28.jpg)
7-28
Converter for DC-Motor Drives
• Four quadrant operation is possible
![Page 29: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/29.jpg)
7-29
Converter Waveforms
• Bi-polar voltage switching
![Page 30: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/30.jpg)
7-30
Converter Waveforms
• Uni-polar voltage switching
![Page 31: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/31.jpg)
7-31
Output Ripple in Converters for DC-Motor Drives
• bi-polar and uni-polar voltage switching
![Page 32: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/32.jpg)
7-32
Switch Utilization in DC-DC Converters
• It varies significantly in various converters
![Page 33: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/33.jpg)
7-33
Equivalent Circuits in DC-DC Converters
• replacing inductors and capacitors by current and voltage sources, respectively
![Page 34: 7-1 Copyright © 2003 by John Wiley & Sons, Inc. Chapter 7 DC-DC Switch-Mode Converters Chapter 7 DC-DC Switch-Mode Converters dc-dc converters for switch-mode](https://reader030.vdocuments.net/reader030/viewer/2022033020/56649d4c5503460f94a29bc3/html5/thumbnails/34.jpg)
7-34
Reversing the Power Flow in DC-DC Conv.
• For power flow from right to left, the input current direction should also reverse