DC-DC转换：LLC esonant converter by BO YANG

【实例截图】

【核心代码】

TABLE OF CONTENT
Chapter 1 Introduction....................................................................................1
1.1 Background and Objectives..........................................................................................................1
1.2 State of the art topologies.............................................................................................................6
1.3 Outline of dissertation.................................................................................................................11
Chapter 2 State of the art topologies and improvements...........................18
2.1 Introduction...................................................................................................................................18
2.2 State of the art topologies and issues........................................................................................19
2.3 Issue with hold up time requirement.........................................................................................28
2.4 Range winding for wide input range.........................................................................................36
2.5 Asymmetrical Winding Asymmetrical Half Bridge...............................................................44
2.6 QSW Synchronous Rectification...............................................................................................54
2.7 Summary and issues....................................................................................................................67
Chapter 3 Integrated Power Electronics Module .......................................72
3.1 Introduction...................................................................................................................................72
3.2 Integrated Power Electronics Module for Front end DC/DC...............................................75
3.3 Performance evaluation...............................................................................................................85
3.4 Summary........................................................................................................................................92
Chapter 4 LLC Resonant Converter............................................................94
4.1 Introduction...................................................................................................................................94
4.2 Three traditional resonant topologies.......................................................................................95
4.3 LLC resonant converter.............................................................................................................106
4.4 Operation of LLC resonant converter.....................................................................................109
4.5 Power stage parameter design of LLC resonant converter.................................................117
4.6 Extension of LLC resonant topology......................................................................................133
4.7 High frequency operation.........................................................................................................135
4.8 Summary......................................................................................................................................140
Chapter 5 Improvements of LLC Resonant Converter...........................142
5.1 Magnetic design for LLC Resonant Converter.....................................................................142
5.2 Over load protection for LLC resonant converter................................................................161
5.3 Integrated power electronics module for LLC......................................................................180
5.4 Summary......................................................................................................................................185
Chapter 6 Small signal analysis and control design of LLC converter..187
6.1 Introduction.................................................................................................................................187
6.2 Extended Describing Function analysis .................................................................................191
6.3 Time domain simulation method.............................................................................................195
6.4 Impact of circuit parameters.....................................................................................................218
6.5 Test verification..........................................................................................................................227
6.6 Compensator design for LLC resonant converter.................................................................229
6.7 Summary......................................................................................................................................236
Chapter 7 Summary and Future Work .....................................................237
7.1 Summary......................................................................................................................................237
7.2 Future work.................................................................................................................................243
Appendix A. Two and Three Components Resonant Tanks ....................247
A.1. Two resonant components resonant tank...............................................................................248
A.2. Three resonant components resonant tank.............................................................................252
Appendix B Operation modes and DC analysis of LLC resonant converter
269
B.1. Operating modes of LLC resonant converter in Region 1 ..................................................270
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B.2. Operating modes of LLC resonant converter in Region 2 ..................................................276
B.3. Operating modes of LLC resonant converter in Region 3 ..................................................282
B.4. DC analysis of LLC resonant converter.................................................................................284
Appendix C. Small signal characteristic of SRC converter......................289
Appendix D. LLC converter model for EDF analysis...............................293
D.1. Process of building LLC circuit model for EDF analysis ...................................................293
D.2. LLC resonant converter model................................................................................................304
Reference ......................................................................................................309
Vita .....................................................................................................................317
Bo Yang List of illustrations
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LIST OF ILLUSTRATIONS
Figure 1.1. Distributed power system structure..........................................................................................2
Figure 1.2. Trend for server system power level........................................................................................4
Figure 1.3. Trend for AC/DC power supply for server.............................................................................5
Figure 1.4. Trend toward lower profile system..........................................................................................5
Figure 1.5. Two stage structure of front-end converter.............................................................................6
Figure 1.6 Primary inverter topologies ........................................................................................................7
Figure 1.7 Secondary rectifier topologies....................................................................................................7
Figure 1.8 The state of the art front-end system.........................................................................................9
Figure 2.1. Two-switch forward converter and operating waveforms..................................................20
Figure 2.2. Full bridge converter and operating waveforms ..................................................................22
Figure 2.3. Schematic of half bridge converter........................................................................................24
Figure 2.4. Operating waveforms of symmetrical half bridge converter.............................................24
Figure 2.5. Operating waveforms of asymmetrical half bridge converter...........................................25
Figure 2.6. Asymmetrical half bridge with current doubler and waveforms .......................................26
Figure 2.7. Loss comparison of three state of the art topologies...........................................................27
Figure 2.8. Output filter inductor volt-sec comparison of three topologies.........................................28
Figure 2.9. Capacitance for hold up time and DC bus voltage after hold up time .............................30
Figure 2.10. Duty cycle range for asymmetrical half bridge with hold up requirement....................31
Figure 2.11. Secondary rectifier voltage and current stress for asymmetrical half bridge................32
Figure 2.12. Test efficiency of asymmetrical half bridge.......................................................................33
Figure 2.13. Duty cycle range for full bridge converter with hold up requirement ...........................34
Figure 2.14. Circulating current of full bridge with different input voltage........................................35
Figure 2.15. Asymmetrical half bridge converter with range winding.................................................37
Figure 2.16 Circuit diagram for normal operation...................................................................................38
Figure 2.17 Circuit diagram for hold up operation..................................................................................38
Figure 2.18 Duty cycle range comparison of asymmetrical half bridge with/without range switch
..................................................................................................................................................................40
Figure 2.19 Diode voltage stress comparison...........................................................................................41
Figure 2.20 Diode average current comparison........................................................................................41
Figure 2.21 Primary switch RMS current comparison............................................................................42
Figure 2.22 Primary switch turn off current comparison........................................................................42
Figure 2.23 Test setup for range winding asymmetrical half bridge....................................................43
Figure 2.24 Test efficiency at normal operation for range winding solution......................................43
Figure 2.25 Range winding for (a) Full bridge (b) current doubler......................................................44
Figure 2.26 Half bridge current doubler with (a) one transformer and (b) Two transformers .........45
Figure 2.27 Topology transformation of current doubler.......................................................................46
Figure 2.28 DC characteristic for different np ratio.................................................................................47
Figure 2.29 Duty cycle range with different turn ratios..........................................................................48
Figure 2.30 Operation waveforms of (a) asymmetrical half bridge and (b) asymmetrical winding
asymmetrical half bridge.....................................................................................................................50
Figure 2.31 Diode voltage stress for asymmetrical winding asymmetrical half bridge....................51
Figure 2.32 Diode current stress for asymmetrical winding asymmetrical half bridge.....................51
Figure 2.33 Output current ripple for asymmetrical winding asymmetrical half bridge...................52
Figure 2.34 Test circuit diagram of asymmetrical winding asymmetrical half bridge......................53
Figure 2.35 Test waveforms of asymmetrical winding asymmetrical half bridge.............................53
Figure 2.36 Test efficiency of asymmetrical winding asymmetrical half bridge...............................53
Figure 2.37 Rectifier diode voltage stress of different topologies ........................................................55
Figure 2.38 Conduction loss comparison of different devices...............................................................55
Figure 2.39 Rectifier diodes current stress for asymmetrical winding asymmetrical half bridge ...57
Figure 2.40 Conduction loss comparison of 200V diode and MOSFET .............................................57
Bo Yang List of illustrations
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Figure 2.41 Circuit diagram of half bridge current doubler with synchronous rectifier....................58
Figure 2.42 Test waveform of synchronous rectifier for front end converter'....................................58
Figure 2.43 Operation waveform of synchronous rectifier for front-end converter...........................59
Figure 2.44 Operation waveform of QSW synchronous rectifier..........................................................60
Figure 2.45 Operating mode 1 of half bridge with synchronous rectifier............................................61
Figure 2.46 Operating mode 2 of half bridge with synchronous rectifier............................................61
Figure 2.47 Operating mode 3 of half bridge with synchronous rectifier............................................61
Figure 2.48 Operating mode 4 of half bridge with synchronous rectifier............................................62
Figure 2.49 Operating mode 5 of half bridge with synchronous rectifier............................................62
Figure 2.50 Primary loss comparison of QSW and conventional synchronous rectifier...................64
Figure 2.51 Test circuit of QSW synchronous rectifier..........................................................................64
Figure 2.52 Test waveform of QSW synchronous rectifier at light load.............................................65
Figure 2.53 Test waveform of QSW synchronous rectifier at heavy load...........................................65
Figure 2.54 Test efficiency of half bridge with QSW synchronous rectifier......................................66
Figure 2.55 Full bridge with QSW synchronous rectifier.......................................................................66
Figure 2.56 Efficiency comparison of different methods.......................................................................67
Figure 2.57. Primary switch total loss for different switching frequency............................................69
Figure 2.58 Half bridge converter with snubber circuit ..........................................................................69
Figure 2.59 Test waveform with and without snubber circuit ...............................................................70
Figure 2.60 Prototype of 200kHz asymmetrical half bridge with discrete components....................70
Figure 3.1 Totem pole switches with parasitic inductance and Q2 Vds (100V/div)..........................73
Figure 3.2 Impact of gate loop parasitic ....................................................................................................74
Figure 3.3 Schematic of front end DC/DC with asymmetrical half bridge current doubler.............75
Figure 3.4 System partitioning of front end DC/DC converter..............................................................77
Figure 3.5 (a) D2BGA IGBT chip-scale package, (b) schematic of FCOF power switching stage
module structure, and (c) FCOF power switching module prototype.........................................78
Figure 3.6 (a) Schematic of Dimple Array Interconnect, (b) integrated DAI power switching stage
module, and (c) prototype Dimple Array Interconnect power switching stage module...........79
Figure 3.7 (a) Schematic integration structure of embedded power module and (b) circuit diagram
..................................................................................................................................................................81
Figure 3.8 Assembly process of embedded power module: (a) top view of embedded power stage,
(b) back view of embedded power stage, (c) components attachment on top, (d) patterned
DBC for base substrate, (e) soldered on substrate, and (f) final encapsulated module. ...........82
Figure 3.9 (a) Spiral integrated LC structure with distributed capacitance and possible external
connection configurations, (b) simplified equivalent circuit, and (c) exploded view...............83
Figure 3.10 Magnetic integrated for asymmetrical half bridge converter............................................84
Figure 3.11 Planar integrated magnetic for current doubler rectifier....................................................84
Figure 3.12 Explored view and photo of passive IPEM .........................................................................85
Figure 3.13 Gate charge curve of IXFH21N50 (a) Datasheet, (b) simulated......................................86
Figure 3.14 V/I characteristic of IXFH21N50 (a) datasheet and (b) simulated..................................87
Figure 3.15 Parasitic of (a) discrete MOSFET and (b) Active IPEM...................................................87
Figure 3.16 Simulation waveforms of Q1 drain source voltage (a) Discrete, and (b) IPEM ...........88
Figure 3.17 Active IPEM turn-off loss reduction.....................................................................................89
Figure 3.18 Voltage overshoots improvement by IPEM ........................................................................89
Figure 3.19 Photos of three prototypes to be compared (a) discrete design, (b) integrated magnetic
design and (c) Passive IPEM design..................................................................................................90
Figure 3.20 Test efficiency of three prototypes........................................................................................90
Figure 3.21 Temperature test setup for three prototypes ........................................................................91
Figure 4.1 Half Bridge Series Resonant Converter..................................................................................96
Figure 4.2 DC characteristic and operating region of SRC....................................................................97
Figure 4.3 Simulation waveforms of SRC.................................................................................................97
Figure 4.4 Half bridge parallel resonant converter..................................................................................99
Figure 4.5 DC characteristic and operating region of PRC..................................................................100
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Figure 4.6 Simulation waveforms of PRC...............................................................................................101
Figure 4.7 Half bridge series parallel resonant converter.....................................................................103
Figure 4.8 DC characteristic and operating region of SPRC................................................................104
Figure 4.9 Simulation waveforms of SPRC............................................................................................104
Figure 4.10 LCC and LLC resonant tank................................................................................................107
Figure 4.11 DC characteristic of LCC resonant converter...................................................................108
Figure 4.12 DC characteristic of LLC resonant converter....................................................................108
Figure 4.13 Half bridge LLC resonant converter...................................................................................108
Figure 4.14 DC characteristic of LLC resonant converter....................................................................111
Figure 4.15 Three operating regions of LLC resonant converter........................................................111
Figure 4.16 Simulated operation waveforms in region 1......................................................................112
Figure 4.17 Simulation waveforms in region 2 ......................................................................................113
Figure 4.18 Circuit diagram during mode 1 in region 2........................................................................114
Figure 4.19 Circuit diagram during mode 2 in region 2........................................................................115
Figure 4.20 Circuit diagram during mode 3 in region 2........................................................................116
Figure 4.21 Operating region for design 1 ..............................................................................................119
Figure 4.22 Simulation waveforms of design 1 with 300V and 400V input voltage.......................119
Figure 4.23 Operating region for design 2 ..............................................................................................120
Figure 4.24 Simulation waveforms of design 2 with 300V and 400V input voltage.......................120
Figure 4.25 Operating region for design 3 ..............................................................................................121
Figure 4.26 Simulation waveforms of design 3 with 300V and 400V input voltage.......................121
Figure 4.27 Primary loss for three designs with Vin=400V.................................................................122
Figure 4.28 Primary loss for three designs with Vin=360V.................................................................123
Figure 4.29 Primary loss for three designs with Vin=300V.................................................................123
Figure 4.30 Test circuit for 200kHz LLC resonant converter..............................................................125
Figure 4.31 Test waveform of LLC converter at full load and (a) 300V input, and (b) 400V input
................................................................................................................................................................126
Figure 4.32 Test efficiency of LLC converter and HB converter at 400V input..............................126
Figure 4.33 Test efficiency of LLC and AHB converter at different input voltage and full load .127
Figure 4.34 Two PWM topologies to be compared (a) AHB, and (b) asymmetrical winding AHB
................................................................................................................................................................128
Figure 4.35 Primary side conduction loss comparison..........................................................................130
Figure 4.36 Primary switches turn off loss comparison........................................................................131
Figure 4.37 Secondary conduction loss comparison..............................................................................132
Figure 4.38 Resonant tanks with desired DC characteristic.................................................................134
Figure 4.39 Half bridge resonant converter with tank W...................................................................... 135
Figure 4.40 Half bridge resonant converter with tank U......................................................................135
Figure 4.41 Simulation waveform of LLC resonant converter............................................................136
Figure 4.42 Switching loss with different Lm for 400kHz LLC resonant converter.......................137
Figure 4.43 Circuit diagram of 400kHz LLC resonant converter.......................................................137
Figure 4.44 Integrated magnetic structure for 400kHz LLC resonant converter..............................137
Figure 4.45 Magnetic components size comparison (a) 200kHz and (b) 400kHz............................138
Figure 4.46 Test circuits of front end DC/DC converter (a) 200kHz AHB, (b) 200kHz LLC, and
(c) 400kHz LLC..................................................................................................................................139
Figure 4.47 Test efficiency of 400kHz LLC resonant converter.........................................................140
Figure 5.1 Magnetic structure for LLC resonant converter..................................................................143
Figure 5.2 Discrete magnetic design (a) schematic (b) physical structure ........................................144
Figure 5.3 Flux density simulation result (a) Inductor, and (b) Transformer....................................144
Figure 5.4 Peak to peak flux density under different input voltage at full load................................145
Figure 5.5 Structure with real transformer..............................................................................................147
Figure 5.6 Desired magnetic components configuration......................................................................147
Figure 5.7 Magnetic components configuration from real transformer.............................................148
Figure 5.8 Voltage stress of output diodes D1 D2 (a): desired structure (b) real transformer.......148
Bo Yang List of illustrations
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Figure 5.9 Integrated Magnetic Designs A..............................................................................................149
Figure 5.10 Flux density simulation result for Design A......................................................................150
Figure 5.11 Center leg flux density for different input voltage...........................................................150
Figure 5.12 general magnetic structures for Integrated magnetic .......................................................152
Figure 5.13 Reluctance model of general integrated magnetic structure...........................................153
Figure 5.14 Circuit model of general integrated magnetic structure ..................................................153
Figure 5.15 Integrated Magnetic Designs B............................................................................................154
Figure 5.16 Electrical circuit model of integrated magnetic structure B ...........................................154
Figure 5.17 Electrical model of connecting dot-marked terminal with unmarked terminal...........155
Figure 5.18 Two operation modes for LLC resonant converter..........................................................155
Figure 5.19 Equivalent-circuit for mode (a)............................................................................................156
Figure 5.20 Design curves for integrated magnetic structure B for LLC converter.........................158
Figure 5.21 Flux density in each leg for integrated magnetic structure B.........................................159
Figure 5.22 Efficiency comparison of integrated and discrete magnetic design for LLC converter
................................................................................................................................................................160
Figure 5.23 Magnetic size comparison of discrete and integrated magnetic.....................................160
Figure 5.24 Simulation waveforms of LLC resonant converter at (a) normal operation, and (b)
short circuit operation........................................................................................................................164
Figure 5.25 Lost of ZVS for LLC resonant converter during over load situation............................165
Figure 5.26 High current stress during over load situation for LLC resonant converter.................165
Figure 5.27 Simplified model of LLC resonant converter during short circuit condition...............166
Figure 5.28 Short circuit output current at different switching frequency.........................................167
Figure 5.29 Average output current vs. switching frequency under short circuit.............................168
Figure 5.30 Change of operating mode with different switching frequency under protection mode
................................................................................................................................................................168
Figure 5.31 Test waveform (top to bottom: Q1 gate signal, Transformer primary current and
resonant cap voltage)..........................................................................................................................169
Figure 5.32 Problems with high switching frequency protection mode.............................................169
Figure 5.33 Control Method of Variable freq PWM control............................................................171
Figure 5.34 Average output current of LLC converter with variable frequency PWM control.171
Figure 5.35 Simulation waveform for D=0.5, 0.4 and 0.2 at short circuit condition.......................172
Figure 5.36 Simulation waveform with PWM control (from top: gate signal of Q1 and Q3, Vds of
Q1 and primary current Ip)................................................................................................................ 172
Figure 5.37 Test waveform for PWM control (Top: Vds of Q1, middle: gate signal of Q1, and Q2,
bottom: primary current)...................................................................................................................173
Figure 5.38 Two LLC resonant converter topologies: (a) Original LLC converter and (b) proposed
clamped LLC converter.....................................................................................................................174
Figure 5.39 Simulation waveforms for two LLC resonant converter topologies: (a) original LLC
converter and (b) clamped LLC converter.....................................................................................175
Figure 5.40 Simulation waveforms under over load condition for (a) original LLC converter and
(b) clamped LLC converter...............................................................................................................176
Figure 5.41 State plane of original and clamped LLC resonant converter........................................177
Figure 5.42 Average output current under over load condition for original LLC converter..........177
Figure 5.43 Average output current under over load condition for clamped LLC converter.........178
Figure 5.44 Design region of clamped LLC resonant converter.........................................................179
Figure 5.45 Test waveform of LLC converter under clamping mode................................................179
Figure 5.46 LLC resonant converter with splitting resonant cap and clamping diodes ..................181
Figure 5.47 Schematics of passive IPEM for AHB and LLC r converter..........................................182
Figure 5.48 Capacitor integration for LLC resonant converter...........................................................182
Figure 5.49 Two passive IPEM structures for LLC resonatn covnerter.............................................183
Figure 6.1 LLC resonant converter with feedback control...................................................................188
Figure 6.2 Circuit parameters for extended describing function analysis ..........................................192
Figure 6.3 Impact of harmonic order on the accuracy of EDF method in region 1..........................193
Bo Yang List of illustrations
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Figure 6.4 Impact of harmonic order on the accuracy of EDF method in region 2..........................194
Figure 6.5 Procedure for simulation method to analyze small signal characteristic ........................195
Figure 6.6 Circuit setup for first step simulation....................................................................................196
Figure 6.7 Circuit setup for second step simulation...............................................................................196
Figure 6.8 System poles and zeros of LLC in region 1 with different switching frequency..........198
Figure 6.9 Input conductance of LLC converter in region 1................................................................199
Figure 6.10 Output impedance of LLC resonant converter in region 1..............................................199
Figure 6.11 Audio susceptibility of LLC converter in region 1..........................................................200
Figure 6.12 System poles and zeros of LLC converter in region 2.....................................................201
Figure 6.13 Input conductance of LLC resonant converter in region 2..............................................201
Figure 6.14 Output impedance of LLC resonant converter in region 2..............................................202
Figure 6.15 Audio susceptibility of LLC resonant converter in region 2 ..........................................202
Figure 6.16 LLC converter setup for small signal analysis ..................................................................204
Figure 6.17 Operating region of LLC resonant converter....................................................................205
Figure 6.18 Bode plot of control to output transfer function for LLC resonant converter..............205
Figure 6.19 Bode plot of control to output transfer function of LLC resonant converter in region 1
................................................................................................................................................................206
Figure 6.20 Bode plot of control to output transfer function of LLC resonant converter in region 2
................................................................................................................................................................ 207
Figure 6.21 Bode plot of control to output transfer function of LLC resonant converter with load
variation in region 1(fr=250kHz, fs=300kHz)...............................................................................210
Figure 6.22 Bode plot of control to output transfer function of LLC resonant converter with load
variation in region 1(fr=250kHz, fs=300kHz) (full load to 25% load).....................................211
Figure 6.23 Bode plot of control to output transfer function of LLC resonant converter with load
variation in region 1(fr=250kHz, fs=300kHz) (25% to no load)................................................212
Figure 6.24 Bode plot of control to output transfer function of LLC resonant converter with load
variation in region 2(fr=250kHz, fs=200kHz)...............................................................................214
Figure 6.25 Bode plot of control to output transfer function of LLC resonant converter with load
variation in region 2(fr=250kHz, fs=200kHz) (full load to 25% load).....................................215
Figure 6.26 Bode plot of control to output transfer function of LLC resonant converter with load
variation in region 2(fr=250kHz, fs=200kHz) (25% to 10% load)............................................216
Figure 6.27 Bode plot of control to output transfer function of LLC resonant converter with load
variation in region 2(fr=250kHz, fs=200kHz) (10% to no load)................................................217
Figure 6.28 Simulation setup for output capacitor impact on small signal characteristic...............218
Figure 6.29 Bode plot of control to output transfer function with different output capacitance with
switching frequency 300kHz(region 1)...........................................................................................219
Figure 6.30 Bode plot of control to output transfer function with different output capacitance with
switching frequency 200kHz(region 2)...........................................................................................220
Figure 6.31 Simulation setup for magnetizing inductance impact on small signal characteristic .221
Figure 6.32 Bode plot of control to output transfer function with different magnetizing inductance
with switching frequency 300kHz(region 1)..................................................................................222
Figure 6.33 Bode plot of control to output transfer function with different magnetizing inductance
with switching frequency 200kHz(region 2)..................................................................................223
Figure 6.34 Simulation setup for resonant tank impedance impact on small signal characteristic 224
Figure 6.35 Bode plot of control to output transfer function with different resonant inductance
with switching frequency 300kHz(region 1)..................................................................................225
Figure 6.36 Bode plot of control to output transfer function with different resonant inductance
with switching frequency 200kHz(region 2)..................................................................................226
Figure 6.37 Test setup up for small signal characterization of LLC converter.................................227
Figure 6.38 Bode plot of control to output transfer function at full load in region 1.......................228
Figure 6.39 Bode plot of control to output transfer function at full load in region 2.......................229
Figure 6.40 Compensator for PWM converter.......................................................................................230
Figure 6.41 Compensator structures for LLC resonant converter.......................................................230
Bo Yang List of illustrations
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Figure 6.42 Small signal characteristic of LLC converter in region 2................................................231
Figure 6.43 Load impact on small signal characteristic of LLC converter in region 2 ...................231
Figure 6.44 Small signal characteristic of LLC converter in region 1................................................232
Figure 6.45 Load impact on small signal characteristic of LLC converter in region 1 ...................233
Figure 6.46 Compensator designed for LLC resonant converter.........................................................234
Figure 6.47 Plant bode plot and loop gain bode plot in region 1.........................................................234
Figure 6.48 Plant bode plot and loop gain bode plot in region 2.........................................................235
Figure 6.49 Test result of load change from no load to full load........................................................235
Figure 6.50 Test result of load change from full load to no load........................................................235
Figure 7.1 LLC resonant tank and LLC resonant tank with passive current shaping......................244
Figure 7.2 Simulation waveform of LLC resonant converter..............................................................244
Figure 7.3 Simulation waveform of LLC resonant converter with passive current shaping..........244
Figure A.1 Input type for DC/DC converter...........................................................................................248
Figure A.2 Input type for DC/DC converter...........................................................................................248
Figure A.3 Two components resonant tanks...........................................................................................249
Figure A.4 DC characteristic of two components tank A.....................................................................250
Figure A.5 DC characteristic of two components tank B .....................................................................250
Figure A.6 DC characteristic of two components tank C .....................................................................251
Figure A.7 DC characteristic of two components tank D.....................................................................251
Figure A.8 Components configuration for three components resonant tank.....................................252
Figure A.9. Resonant tank for components configuration 1.................................................................253
Figure A.10. Resonant tank for components configuration 2 ..............................................................253
Figure A.11. Resonant tank for components configuration 3 ..............................................................253
Figure A.12. Resonant tank for components configuration 4 ..............................................................254
Figure A.13. Resonant tank for components configuration 5 ..............................................................254
Figure A.14. Resonant tank for components configuration 6 ..............................................................254
Figure A.15. Resonant tank for components configuration 7 ..............................................................255
Figure A.16. Resonant tank for components configuration 8 ..............................................................255
Figure A.17. Resonant tank for components configuration 9 ..............................................................255
Figure A.18. Resonant tank for components configuration 10............................................................256
Figure A.19. Resonant tank for components configuration 11............................................................256
Figure A.20. Resonant tank for components configuration 12............................................................257
Figure A.21. Resonant tank for components configuration 13............................................................257
Figure A.22. Resonant tank for components configuration 15............................................................258
Figure A.23. DC characteristic of tank C................................................................................................260
Figure A.24. DC characteristic of tank D................................................................................................261
Figure A.25. DC characteristic of tank G................................................................................................261
Figure A.26. DC characteristic of tank H................................................................................................262
Figure A.27. DC characteristic of tank K................................................................................................262
Figure A.28. DC characteristic of tank L.................................................................................................263
Figure A.29. DC characteristic of tank O................................................................................................263
Figure A.30. DC characteristic of tank S.................................................................................................264
Figure A.31. DC characteristic of tank U................................................................................................264
Figure A.32. DC characteristic of tank V................................................................................................265
Figure A.33. DC characteristic of tank W ...............................................................................................265
Figure A.34. DC characteristic of tank X................................................................................................266
Figure A.35. DC characteristic of tank Z.................................................................................................266
Figure A.36. DC characteristic of tank G1..............................................................................................267
Figure A.37. DC characteristic of tank H1..............................................................................................267
Figure B.1 DC characteristic of LLC resonant converter.....................................................................270
Figure B.2 Waveform of operation mode 1 in region 1 for LLC resonant converter'.....................271
Figure B.3 Waveform of operation mode 2 in region 1 for LLC resonant converter'.....................273
Figure B.4 Waveform of operation mode 3 in region 1 for LLC resonant converter'.....................275
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Figure B.5 Waveform of operation mode 1 in region 2 for LLC resonant converter'.....................277
Figure B.6 Waveform of operation mode 2 in region 2 for LLC resonant converter'.....................279
Figure B.7 Waveform of operation mode 3 in region 2 for LLC resonant converter'.....................281
Figure B.8 Waveform in region 3 for LLC resonant converter...........................................................283
Figure B.9 Simplified topology with fundamental component assumption......................................284
Figure B.10 DC characteristic from simplified model..........................................................................286
Figure B.11 DC characteristic from simulation method.......................................................................286
Figure B.12 Error of simplified circuit model........................................................................................287
Figure C.1 SRC circuit for small signal analysis ...................................................................................289
Figure C.2 Bode plot of control to output transfer function of Series Resonant Converter............290
Figure D.1 Circuit diagram and notification for extended describing function analysis.................294
Figure D.2 Simulation waveform of LLC converter in region 1.........................................................295
Figure D.3 Topology modes and progressing condition for region 1.................................................296
Figure D.4 Simulation waveform of LLC converter in region 2.........................................................300
Figure D.5 Topology modes and progressing condition for region 2.................................................300
Bo Yang List of Table
xvi
LIST OF TABLES
Table 2-1. Input range of front-end DC/DC converter vs. DC bus capacitance.................................30
Table 2-2 Difference between two asymmetrical half bridge design...................................................33
Table 3-1 Comparison of three prototypes................................................................................................91
Table 3-2 Temperature test results of three prototypes...........................................................................91
Table 4-1 Summary of three LLC resonant converter designs............................................................122
Table 4-2 Loss breakdown comparison of AHB and LLC...................................................................132
Table A-1 Classification of three components resonant tanks.............................................................259
Table A-2 Three components resonant tanks with voltage source input............................................ 260