EE 136 Project Presentation The Diagonal Half-Bridge Flyback Converter Non-isolated Self-Oscillating...
-
date post
19-Dec-2015 -
Category
Documents
-
view
280 -
download
5
Transcript of EE 136 Project Presentation The Diagonal Half-Bridge Flyback Converter Non-isolated Self-Oscillating...
![Page 1: EE 136 Project Presentation The Diagonal Half-Bridge Flyback Converter Non-isolated Self-Oscillating Flyback Converter with Primary Current-Mode Control.](https://reader035.fdocuments.us/reader035/viewer/2022081416/56649d405503460f94a19869/html5/thumbnails/1.jpg)
EE 136 Project Presentation
• The Diagonal Half-Bridge Flyback Converter
• Non-isolated Self-Oscillating Flyback Converter with Primary Current-Mode Control
• Isolated Self-Oscillating Flyback Converter with Primary Current-Mode Control
• Presented By: Latt M. Tee Naw Sandar Shwe
![Page 2: EE 136 Project Presentation The Diagonal Half-Bridge Flyback Converter Non-isolated Self-Oscillating Flyback Converter with Primary Current-Mode Control.](https://reader035.fdocuments.us/reader035/viewer/2022081416/56649d405503460f94a19869/html5/thumbnails/2.jpg)
The Diagonal Half-Bridge Flyback Converter
– This converter is suitable for power FETs operation
– Same design procedure applies as a single-ended flyback converter
![Page 3: EE 136 Project Presentation The Diagonal Half-Bridge Flyback Converter Non-isolated Self-Oscillating Flyback Converter with Primary Current-Mode Control.](https://reader035.fdocuments.us/reader035/viewer/2022081416/56649d405503460f94a19869/html5/thumbnails/3.jpg)
Circuit Analysis for Half-Bridge Flyback Converter
• Switches is driven by control circuit, both “on” and “off” together
• Flyback action takes place during “off” period
• Cross-connected diodes D1 and D2 return excess flyback energy to supply lines
• D1 and D2 eliminates the need of an energy recovery winding or large snubbing components.
![Page 4: EE 136 Project Presentation The Diagonal Half-Bridge Flyback Converter Non-isolated Self-Oscillating Flyback Converter with Primary Current-Mode Control.](https://reader035.fdocuments.us/reader035/viewer/2022081416/56649d405503460f94a19869/html5/thumbnails/4.jpg)
Schematic Diagram for Half-Bridge Flyback Converter
![Page 5: EE 136 Project Presentation The Diagonal Half-Bridge Flyback Converter Non-isolated Self-Oscillating Flyback Converter with Primary Current-Mode Control.](https://reader035.fdocuments.us/reader035/viewer/2022081416/56649d405503460f94a19869/html5/thumbnails/5.jpg)
The Circuit Diagram When Switches ‘On’ & ‘Off’ and Voltage and Current Waveform
D1
D2D8
D4
D5
D6C1
C2
TFR1P2W1C3 R1
V1
S1
S2
D1
D2D8
D4
D5
D6C1
C2
TFR1P2W1
D3
C3 R1V1
TRAPEZ1
TRIANG1
![Page 6: EE 136 Project Presentation The Diagonal Half-Bridge Flyback Converter Non-isolated Self-Oscillating Flyback Converter with Primary Current-Mode Control.](https://reader035.fdocuments.us/reader035/viewer/2022081416/56649d405503460f94a19869/html5/thumbnails/6.jpg)
Schematic DiagramVoltage and Current waveforms
(using Simplorer Software)
S1
S2
D1
D2D8
D4
D5
D6C1
C2
TFR1P2W1
D3
C3 R1V1
TRAPEZ1
TRIANG1
D6.I [A] 1e-036
-1.3e-018
D5.I [A] 1.3e-018
-1e-036
TFR1P2W1.V1 [V] 1p
-3p
TFR1P2W1.I1 [A] 2.9e-017
-1.2e-018
t [s] 0 4n0.5n 1n 1.5n 2n 2.5n 3n 3.5n
![Page 7: EE 136 Project Presentation The Diagonal Half-Bridge Flyback Converter Non-isolated Self-Oscillating Flyback Converter with Primary Current-Mode Control.](https://reader035.fdocuments.us/reader035/viewer/2022081416/56649d405503460f94a19869/html5/thumbnails/7.jpg)
Advantages of this converter
• Using the diodes D1 and D2 is good for over-voltage stress.
• Flyback action returns the stored energy to the supply line.
• Do not need bifilar-wound energy recovery winding
• Reduce the cost and eliminate unreliable source.
![Page 8: EE 136 Project Presentation The Diagonal Half-Bridge Flyback Converter Non-isolated Self-Oscillating Flyback Converter with Primary Current-Mode Control.](https://reader035.fdocuments.us/reader035/viewer/2022081416/56649d405503460f94a19869/html5/thumbnails/8.jpg)
Self-oscillating flyback converter
• Low component count without loss of performance
• Widely used in low power applications such as computers, video display terminals and so on
![Page 9: EE 136 Project Presentation The Diagonal Half-Bridge Flyback Converter Non-isolated Self-Oscillating Flyback Converter with Primary Current-Mode Control.](https://reader035.fdocuments.us/reader035/viewer/2022081416/56649d405503460f94a19869/html5/thumbnails/9.jpg)
Frequency variation as a function of loadNon-isolated self-oscillating flyback converter
0
20
40
60
80
100
120
140
0 20 40 60 80 100 120
load %
freq.
kHz
• Type C operation• Variable ‘on’ time,
‘off’ time, and repetition rate (freq.)
• Has a more desirable characteristic
![Page 10: EE 136 Project Presentation The Diagonal Half-Bridge Flyback Converter Non-isolated Self-Oscillating Flyback Converter with Primary Current-Mode Control.](https://reader035.fdocuments.us/reader035/viewer/2022081416/56649d405503460f94a19869/html5/thumbnails/10.jpg)
Circuit Diagram of non-isolated flyback converter
![Page 11: EE 136 Project Presentation The Diagonal Half-Bridge Flyback Converter Non-isolated Self-Oscillating Flyback Converter with Primary Current-Mode Control.](https://reader035.fdocuments.us/reader035/viewer/2022081416/56649d405503460f94a19869/html5/thumbnails/11.jpg)
Base drive current waveform of self-oscillating converter
![Page 12: EE 136 Project Presentation The Diagonal Half-Bridge Flyback Converter Non-isolated Self-Oscillating Flyback Converter with Primary Current-Mode Control.](https://reader035.fdocuments.us/reader035/viewer/2022081416/56649d405503460f94a19869/html5/thumbnails/12.jpg)
Schematic and waveforms using Simplorer software
R1
R2
R3
R7
R5
R6
R4
R8 R9
R10
C1 C2E1
D1
BJT1
BJT2
TWT
TWT1
D2C3
+
-
OPV51
TFR1P11
D3
D4
C4E2
BJT1.I [A]
t [s]
2.8m
0
0.5m
1m
1.5m
2m
0 0.4m50u 0.1m 0.15m 0.2m 0.25m 0.3m
R2.I [A]
t [s]
0
-2.8m
-2m
-1.5m
-1m
-0.5m
0 0.4m50u 0.1m 0.15m 0.2m 0.25m 0.3m
![Page 13: EE 136 Project Presentation The Diagonal Half-Bridge Flyback Converter Non-isolated Self-Oscillating Flyback Converter with Primary Current-Mode Control.](https://reader035.fdocuments.us/reader035/viewer/2022081416/56649d405503460f94a19869/html5/thumbnails/13.jpg)
Isolated self-oscillating flyback converter
• The input and output voltage does not depend on each other
• Optocoupler is used as a feedback loop• Transistor Q2 and R4 control the current-
mode• Input voltage +300 V DC and output
voltage +12V is applied to the circuit for self-oscillating
![Page 14: EE 136 Project Presentation The Diagonal Half-Bridge Flyback Converter Non-isolated Self-Oscillating Flyback Converter with Primary Current-Mode Control.](https://reader035.fdocuments.us/reader035/viewer/2022081416/56649d405503460f94a19869/html5/thumbnails/14.jpg)
Non-isolated self oscillating circuit
![Page 15: EE 136 Project Presentation The Diagonal Half-Bridge Flyback Converter Non-isolated Self-Oscillating Flyback Converter with Primary Current-Mode Control.](https://reader035.fdocuments.us/reader035/viewer/2022081416/56649d405503460f94a19869/html5/thumbnails/15.jpg)
The wave form of Q1 and Q2• Q1 Ic increase
Ie increase
• Vbe 0.6V
Q2 turn on
![Page 16: EE 136 Project Presentation The Diagonal Half-Bridge Flyback Converter Non-isolated Self-Oscillating Flyback Converter with Primary Current-Mode Control.](https://reader035.fdocuments.us/reader035/viewer/2022081416/56649d405503460f94a19869/html5/thumbnails/16.jpg)
Simulation result
C1
C2
C3
C4
C5
C6
D1
D2R1
D3
Diode601
L1
R2
R3
R4
R5
R6
R7
R8
TWT
TWT1
Diode602
R9
D4
R11
R12
E2R10
C7
R5.V [V]
t [s]
0.1k
-0.25k
0
-0.15k
-0.1k
-50
0 9.5m1m 2m 3m 4m 5m 6m 7m 8m
NPN61
NPN63
NPN62
THY41
NPN61.VBE
t [s]
4k
0
1k
1.5k
2k
2.5k
3k
0 9.5m1m 2m 3m 4m 5m 6m 7m
NPN63.IC
t [s]
0.3
-50m
50m
0.1
0.15
0.2
0 9.5m1m 3m 5m 7m
NPN63.I_B
t [s]
0.14
-20m
20m
40m
60m
80m
0.1
0 9.5m1m 3m 5m 7m
![Page 17: EE 136 Project Presentation The Diagonal Half-Bridge Flyback Converter Non-isolated Self-Oscillating Flyback Converter with Primary Current-Mode Control.](https://reader035.fdocuments.us/reader035/viewer/2022081416/56649d405503460f94a19869/html5/thumbnails/17.jpg)
Advantages
• The system as if the primary is a high-impedance current source.
• Results in a first order transfer function.
• The control circuit may have high frequency response.
• Line ripple rejection and stability improved.
• Primary current limiting is provided.
![Page 18: EE 136 Project Presentation The Diagonal Half-Bridge Flyback Converter Non-isolated Self-Oscillating Flyback Converter with Primary Current-Mode Control.](https://reader035.fdocuments.us/reader035/viewer/2022081416/56649d405503460f94a19869/html5/thumbnails/18.jpg)
Conclusion
• Low cost
• Fewer components need
• Widely used in low power application