Multi-Phase Full/Half Wave Type Resonant Converter with Automatic Current Balance against Element Variation Chen-Hao Zhang*, Yi-Fei Sun, Tran Minh Tri, Yasunori Kobori, Anna Kuwana,Haruo Kobayashi Gunma University
Multi-Phase Full/Half Wave Type Resonant Converter
with Automatic Current Balance against Element Variation
Chen-Hao Zhang*, Yi-Fei Sun, Tran Minh Tri,Yasunori Kobori, Anna Kuwana,Haruo Kobayashi
Gunma University
1Contents
•Research background•Full/Half wave type soft switching converter •Multi-phase soft switching converter• Automatic current balance technology• Conclusion
2Contents
•Research background•Full/Half wave type soft switching converter •Multi-phase soft switching converter• Automatic current balance technology• Conclusion
3Research Background
・CPU for server
DC 12V
SocketAC-DC converter
AC 100V DC-DC converter
DC 1.3V, I >100A
・LED Display ・Digital Camera ・Smartphone
Large CurrentFast Response
Supplies
4
Soft-SwitchingZVS, ZCS
Multi Function
Down-SizingLow Cost
Large Current
FastResponse
HighEfficiency
Low Noise
SIMO
EMI Reduction
IC, SIMO
Ripple Control(Hysteretic Cont.)
PWM ControlBuck Converter
Multi-Phase+ Soft-
Switching+Automatic Current Balance
EMI Reduction+ Ripple Control
Multi-Phase
Power supply research of Gunma University
Today’sReport
C6-4
5Today’s Presentation
Large Current Multi-Phase
PWM ControlledBuck Converter
Fast Response
High Efficiency
Ripple Controlled
Multi-PhaseSoft Switching
ConverterC6-1:Reported
Full/Half Wave Resonance
Already produced4 ~ 6 Phase
Problem 1
ElementVariation
Problem 2
CurrentImbalance
6Research Objective
Development of power supply with ・ Multi-phase soft switching converters with full or half wave resonance ・ Automatic current balance technology against resonant element variation
1) How to configurate the multi phase constructions when there is no fixed clock pulse? 2) How to control the current balance automatically?
Technical Problems
Objective
7Contents
•Research background•Full/Half wave type soft switching converter •Multi-phase soft switching converter• Automatic current balance technology• Conclusion
8Soft Switching Converter (Full Wave)
Soft Switching Converter with Full Wave Resonance
Fig. Full wave soft switching converter
*Resonant elements Lr, Cr, Dr are added.*SW turns ON at Vr=Vd.*Vo=D・Vi :D is the duty ratio of PWM.
Fig. Signals of full wave converter
*Conditions: F=760kHz Vi=12V, Vo=7.0V, Io=1.0A Lo=50µH, Co=470µF Lr= 20µH, Cr=100pF
Ir
Ids
Vr T0 T1 T2 T3Ta Ts
Vi0
Io
0
Io0
Vr
Ir
PWM
Ids
Turn onVLO
Comp2
9Soft Switching Converter (Half Wave)
*PWM Duty shows period of TOFF.*Duty ratio is represented by inductor current.*Operation frequency depends on output current Io.
Fig. Half wave soft switching converter
*Resonant Dr is deleted.*SW turns ON at Vr=Vd but Vo is not =D・Vi (D is duty ratio of PWM)
Fig. Signals of half wave converter
Comp2
10Contents
•Research background•Full/Half wave type soft switching converter •Multi-phase soft switching converter• Automatic current balance technology• Conclusion
11Multi Phase Buck Converter
★Twoーphase is provided by Flip-Flop which divides the clock pulse.
*PWM2 is opposite phase. *Ripple of ΣIL is half of IL1 .
PWM1
IL1
PWM2
IL2
ΣIL
SW
CoVi
Di
AMPVo
Vr
R L
Main-converter
SAW1
Div.
Sub-converter
PWM1
Comp
L1
Vi
Clock
CK-controller
Ph1
Ph2
ΣIL
PWM2
SAW2
IL1
IL2
CK1
SAW1
ΔVE
12Dual-Phase Soft-switching Converter
●Opposite phase is generated like ripple-controlled converter.
Fig. Dual phase switching converter Fig. Signals of dual phase converter
Io
SAW1
Vpeak/2Compare SAW2
180°delay
13Contents
•Research background•Full/Half wave type soft switching converter •Automatic current balance technologyConclusion
14Imbalance of Dual-Phase Converter
LC L(C+ΔC)Temperature or other effects Vo↓ Io↑ Imbalance
PWM1
Resonance
SAW1
ΔT
element variation
Switch on time is stable, but the closing time is extended
off
on
TTTVV
oninO =
15
*When phase2 is shift to delay, the current IL2 will decrease. *Detecting the current balance, When IL2 > IL1, make the bias voltage VB down. ⇒ Phase 2 shifts delayed and IL2 is decreased.
Automatic Current balance Technology
PWM1
IL1
PWM2
IL2
ΣIL
VB
Ph2
Vc
16
*Current balance 1) Current balance with ideal elements 2) Current imbalance with element variation
●Demerit of current imbalance 1) Output ripple increases! 2) Inductor current increases & loss goes up & heat up. 3) Semiconductor (SW) needs large current & heat capacity
Imbalance of Dual-Phase Converter
Fig. Current balance with ideal elements
Fig. Current imbalance with element variation
Io
IL1
IL1≠IL2≠Io/2
IoIL1/IL2
IL1=IL2=Io/2
IL2Imbalance
17Automatic Current balance Technology
Current balance control signal
PWM2
NEW PWM2
Vpeak-hold
SAWVc
Vc-α
VC
SAWCompare PWM2
VC+α
SAWCompare New PWM2
Balance
18Generation of Four-Phase Pulses
Voltage Divider & Comparator
Operation waveformMain PWM
SAW
SAW Generator & Peak Hold
PWM4
PWM3
PWM2
PUL4
PUL3
PUL2
time/mSecs 2uSecs/div
2.206 2.208 2.21 2.212 2.214 2.216 2.218
V
2
4
6
8
10
12
VPeak-hold
[V/V]
Reset
PWM1
PWM2
PWM3
PWM4
SAW
Vcomp PUL2 PUL3 PUL4
[V/V]
[t/ms]
Fig. Signals of Four-phase converter
19Current Balance of four-phase Converter
Large load current achieved
Good current balance during transient response
Good current balance
IL1, IL2, IL3, IL4
[I/A]
[t/mS]
Io
IL1, IL2, IL3, IL4
[t/mS]
[I/A]
Without element variations ⊿L, ⊿TCOT(=⊿C), ⊿VS/H
★Simulation Result
20Imbalance current (Dual-phase)
10μH 11μH
InductorMain power supply
+ 10%
Io = 6AIL1 =4.3A , IL2 =1.7A
ΔIL = (IL1 -IL2 ) -- = |4.3-1.7|=2.6A Error Ratio: δ = (Io/2-In)/Io/2 =(3-1.7)/3=> 43%
●Two Phase: With element variation (Inductance)
☹
Fig.Dual-phase current imbalance
21Balance current(Dual-phase)
Io = 6AIL1 =IL2 =3A
Good current balance
●Two Phase :Result of proposed method with good current balance
� Fig. Multi-phase current balance
10μH 11μH
InductorMain power supply
+ 10%
22Imbalance current (Multi-phase)
10μH 11μH
InductorMain power supply
+ 10%
Io = 8.58AIL1 =5.43A , IL2 =3.15A
ΔIL = (IL1 -IL2 ) -- = |5.43-3.15|=2.28A Error Ratio: δ = (Io/2-In)/Io/2 =(4.29-3.15)/4.29=> 27 %
●Four Phase: With element variation (Inductance)
☹Fig. Multi-phase current imbalance
23Balance current(Multi-phase)
Io = 6.81AIL1 =IL2 =3.40A
Good current balance
●Four Phase :Result of proposed method with good current balance
�
Fig. Multi-phase current balance
10μH 11μH
InductorMain power supply
+ 10%
24Conclusion
l The peak hold voltage is extracted by the peak hold circuit to compare it with the SAW1 signal, producing a SAW2 signal with a 180°delay, thereby implementing a dual wave converter without a clock signal. This method has automatic adjustment capability and has faster response speed than traditional PLL methods.
l We have proposed multi-phase full wave and half wave type voltage resonant converters with automatic current balance against the LC elements variation.
25
Thank you for your attention
26
Q&Aに必要と思われる資料を以下に添付しておくと良い
27Operation of Buck Converter
Vin Vo
Q L
CDPWM
Buck Converter
Vo+-
L
C+
-
+-
Vo+
-
Vin +-
L+ -
C
Q VEO
VEO
DVin
On State: Q on D offIL
IL
VQ
IL
VEO
Ton Toff
ΔIL+
ΔIL-
Off State: Q off D on
Volt-second balance
VLon = Vin-Vo= L・(⊿iL+/⊿ton)
VLoff =-Vo= L・(⊿iL-/⊿toff)
⊿iL+ = ⊿iL-
On State
Off State
Vo = Vin
TsVQ