Download - Switching-Mode Regulators
![Page 1: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/1.jpg)
ECE 442 Power Electronics 1
Switching-Mode Regulators
Convert an unregulated DC voltage into a regulated DC voltage
![Page 2: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/2.jpg)
ECE 442 Power Electronics 2
Buck Regulator
BJT Chopper L-C Filter Load
Control Voltage Freewheeling Diode
Output Voltage is Less Than the Input Voltage
![Page 3: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/3.jpg)
ECE 442 Power Electronics 3
Mode 1 Operation – Q1 switched ON
Input current flows through L, C, and the Load – rises linearly
![Page 4: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/4.jpg)
ECE 442 Power Electronics 4
Mode 2 Operation – Q1 switched OFF
Inductor current continues to flow through L, C, the Load, and Dm, falling linearly until Q1 is turned ON again.
![Page 5: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/5.jpg)
ECE 442 Power Electronics 5
Waveforms for the Buck Regulator
![Page 6: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/6.jpg)
ECE 442 Power Electronics 6
Summary for the Buck Regulator
• The peak-to-peak ripple current is
• The peak-to-peak ripple voltage is
(1 )sV k kI
fL
2
(1 )
8s
c
V k kV
LCf
![Page 7: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/7.jpg)
ECE 442 Power Electronics 7
Summary for continuous current case
• The critical value of the inductor is
• The critical value of the capacitor is
(1 )
2c
k RL L
f
2
1
16c
kC C
Lf
![Page 8: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/8.jpg)
ECE 442 Power Electronics 8
Boost RegulatorOutput Voltage is Greater Than the Input Voltage
![Page 9: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/9.jpg)
ECE 442 Power Electronics 9
Mode 1 Operation – M1 switched ON
Input current flows through L and M1 (linearly)
![Page 10: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/10.jpg)
ECE 442 Power Electronics 10
Mode 2 Operation – M1 switched OFF
Current that flowed through the transistor now flows through L, C, the Load, and diode Dm until transistor M1 is turned ON again.
![Page 11: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/11.jpg)
ECE 442 Power Electronics 11
Waveforms for the Boost Regulator
![Page 12: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/12.jpg)
ECE 442 Power Electronics 12
Summary for the Boost Regulator
• The peak-to-peak ripple current is
• The peak-to-peak ripple voltage is
sV kIfL
ac
I kV
fC
![Page 13: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/13.jpg)
ECE 442 Power Electronics 13
Summary for continuous current case
• The critical value of the inductor is
• The critical value of the capacitor is
(1 )
2c
k k RL L
f
2c
kC C
fR
![Page 14: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/14.jpg)
ECE 442 Power Electronics 14
Buck-Boost Regulator
The output voltage could be less than or greater than the input voltage
The polarity of the output voltage is opposite to the polarity of the input voltage Vs – Inverting Regulator
![Page 15: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/15.jpg)
ECE 442 Power Electronics 15
Mode 1 Operation – Q1 turned ON
Input current flows through inductor L and Q1 linearly.
![Page 16: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/16.jpg)
ECE 442 Power Electronics 16
Mode 2 Operation – Q1 switched OFF
Current flowing through L now flows through L, C, Dm and the Load.
![Page 17: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/17.jpg)
ECE 442 Power Electronics 17
Waveforms for the Buck-Boost Regulator
![Page 18: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/18.jpg)
ECE 442 Power Electronics 18
Summary for the Buck-Boost Regulator
• The peak-to-peak ripple current is
• The peak-to-peak ripple voltage is
sV kIfL
ac
I kV
fC
![Page 19: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/19.jpg)
ECE 442 Power Electronics 19
Summary for continuous current case
• The critical value of the inductor is
• The critical value of the capacitor is
2c
kC
fR
(1 )
2c
k RL L
f
![Page 20: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/20.jpg)
ECE 442 Power Electronics 20
Converter with a highly inductive Load
Input Current is “pulse” shaped
![Page 21: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/21.jpg)
ECE 442 Power Electronics 21
Connect an input filter
Filter out the converter-generated harmonics from the supply line.
![Page 22: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/22.jpg)
ECE 442 Power Electronics 22
Equivalent circuit for the converter-generated harmonic currents
![Page 23: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/23.jpg)
ECE 442 Power Electronics 23
Example 5.10
![Page 24: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/24.jpg)
ECE 442 Power Electronics 24
Buck Chopper for PSpice Simulation
![Page 25: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/25.jpg)
ECE 442 Power Electronics 25
Results from PSpice
![Page 26: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/26.jpg)
ECE 442 Power Electronics 26
Fourier Coefficients of the input current
![Page 27: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/27.jpg)
ECE 442 Power Electronics 27
Vs110 V
Q1
BJT_NPN_VIRTUAL*
L1681.82uH
L240.91uH
C18.33uF
R12 Ohm
D1DIODE_VIRTUAL
XFG1R2250 Ohm
46
7
8
R31 Ohm
1
5
Vx0 V
3
0
Vy
0 V 11
12
Example 5.10 in MultiSim
![Page 28: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/28.jpg)
ECE 442 Power Electronics 28
![Page 29: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/29.jpg)
ECE 442 Power Electronics 29
Fourier Coefficients of the Input Current
![Page 30: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/30.jpg)
ECE 442 Power Electronics 30
![Page 31: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/31.jpg)
ECE 442 Power Electronics 31
![Page 32: Switching-Mode Regulators](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56813c62550346895da5ec01/html5/thumbnails/32.jpg)
ECE 442 Power Electronics 32