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Prof. Byoung-Kuk Lee, Ph.D. Energy Mechatronics Lab. School of Information and Communication Eng. Sungkyunkwan University Tel: +82-31-299-4581 Fax: +82-31-299-4612 http://seml.skku.ac.kr EML: [email protected]
-부스트 컨버터, 벅부스트 컨버터-
전력전자공학
2 / 20
Sungkyunkwan Univ., Energy Mechatronics Lab.
00
( )(1 ) 0
1
1
(0 1)
T
L
i i o
o i
o i
o
from Inductor Flux Linkage balance
v dt
V DT V V D T
V VD
V VD D
V
,s oV V always
비절연형 DC-DC 컨버터 – Boost (I)
Boost Converter Analysis
전력전자공학
3 / 20
Sungkyunkwan Univ., Energy Mechatronics Lab.
Design Consideration
MOSFET or IGBT
• Voltage rating
• Current rating
Diode
• Voltage rating
• Current rating
• Switching speed
Inductor
• Power rating
• Saturation magnetic flux density
Capacitor
• Expected life time
• Ripple current
• Temperature
22
,
(1 )(1 )
2 2
o
sw sw o min
D D VD D RL
f f I
o
o
VDTC
R V
비절연형 DC-DC 컨버터 – Boost (II)
전력전자공학
4 / 20
Sungkyunkwan Univ., Energy Mechatronics Lab.
Waveforms
비절연형 DC-DC 컨버터 – Boost (III)
DT T
t
DT T
t
DT T
t
iS
Imax
Imin
iD
Imax
Imin
DT T
t
SW
Vgate
iL
Imax
Imin
IL
t
vL
VS
VS -VO
DT T
vS
Vo
DT T
t
DT T
t
vD
VO
t
iC
-IO
DT T
DT Tt
vC
전력전자공학
5 / 20
Sungkyunkwan Univ., Energy Mechatronics Lab.
Analysis - Output Current
커패시터 전류평균치
(Capacitor Charge balance) • Output node에서 KCL 적용하면,
0 0 0
,
1 1 1
D C O
T T T
D C O
OD avg O
i i I
i i IT T T
VI I
R
0
,
C D O
OD
where
i i I
Vi
R
∆Vo
≈
Mode 1
Mode 2
비절연형 DC-DC 컨버터 – Boost (IV)
t
iC
-IO
DT T
DT T
t
SW
Vgate
DT T
t
vC
전력전자공학
6 / 20
Sungkyunkwan Univ., Energy Mechatronics Lab.
Analysis – Inductor Current
Mode 2 (Turn-Off, 전류하강구간 : DT<t<T)
LL i
iL
div L V
dt
Vdi
dt L
의기울기로증가
Mode 1 (Turn-On, 전류상승구간 : 0<t<DT)
min min0
min
max
min0
max min
1( ) , ( ,@ )
( 0)
( )
1
t
L i initial
L
L
DT
i
iL
i t V dt I I I steady stateL
I i t
I i t DT
V dt IL
VI I I DT
L
Mode 1
Mode 2
i oLV vdi
dt L
의기울기로감소
max
min
max
min max
1( ) ( )
( )
1( )
(1 )
T
L i oDT
L
T
i oDT
i oL
i t V v dt IL
I i t T
V v dt IL
V VI I I D T
L
비절연형 DC-DC 컨버터 – Boost (V)
DT T
t
DT T
t
SW
Vgate
iL
Imax
Imin
IL
전력전자공학
7 / 20
Sungkyunkwan Univ., Energy Mechatronics Lab.
Boost Converter Simulation
Specification
Pin=100W
Vin=17.5VDC
Vout=30VDC
Vout,ripple<300mV
fs/w=33kHz
R=9ohm
Duty ratio = 0.42
L = 40uH
C = 200uF
비절연형 DC-DC 컨버터 – Boost (VI)
전력전자공학
8 / 20
Sungkyunkwan Univ., Energy Mechatronics Lab.
Simulation
0 DT T ∆iL≈5.5A
iL,avg≈5.7A
iL,avg=1*IO/(1-D)
iS+iD=iL (KCL)
비절연형 DC-DC 컨버터 – Boost (VII)
전력전자공학
9 / 20
Sungkyunkwan Univ., Energy Mechatronics Lab.
0 DT T
VO
VO
비절연형 DC-DC 컨버터 – Boost (VIII)
Simulation
전력전자공학
10 / 20
Sungkyunkwan Univ., Energy Mechatronics Lab.
0 DT T
∆VC≈220mV
-IO
비절연형 DC-DC 컨버터 – Boost (IX)
Simulation
전력전자공학
11 / 20
Sungkyunkwan Univ., Energy Mechatronics Lab.
Output Ripple according to Capacitance
20uF 200uF 380uF
비절연형 DC-DC 컨버터 – Boost (X)
Simulation
전력전자공학
12 / 20
Sungkyunkwan Univ., Energy Mechatronics Lab.
Inductor Current according to Inductance
10uH 40uH 70uH
비절연형 DC-DC 컨버터 – Boost (XI)
Simulation
전력전자공학
13 / 20
Sungkyunkwan Univ., Energy Mechatronics Lab.
s o s oV V or V V
Buck-Boost Converter Analysis
비절연형 DC-DC 컨버터 – Buck-Boost (I)
vS
vo
vD
Vi CL
iL
io
iC
vL
iS
S
D iD
부
하
a
vS
vo
vD
Vi CL
iL
io
iC
vL
iS
S
D iD
부
하
vS
vo
vD
Vi CL
iL
io
iC
vL
iS
S
D iD
부
하
a
a
전력전자공학
14 / 20
Sungkyunkwan Univ., Energy Mechatronics Lab.
)1(
0
D
D
V
VG
i
V
0( ) (1 ) 0L i
Based on Inductor Volt Sec Balance
V V DT V D T
Waveforms
비절연형 DC-DC 컨버터 – Buck-Boost (II)
vD
tDT T
Vi+Vo
DT T
vS
t
Vi+Vo
vL
DT T
t
-Vo
Vi
t
iL
DT T
t
iS
DT T
t
iD
DT T
S:ON, D:OFF S:OFF, D:ON S:ON, D:OFF
IL
전력전자공학
15 / 20
Sungkyunkwan Univ., Energy Mechatronics Lab.
L
V
dt
di iL
min
0
1)( IdtV
Lti
t
iL min
0
max
1)( IdtV
LDTtii
DT
iL DTL
VII i minmax
dt
diLv L
L
DTt 0
Analysis
비절연형 DC-DC 컨버터 – Buck-Boost (III)
vS
vo
vD
Vi CL
iL
io
iC
vL
iS
S
D iD
부
하
a
iD
t
Imax
Imin
DT T
iSImax
Imin
tDT T
iL
t
Imax
Imin
DT T
전력전자공학
16 / 20
Sungkyunkwan Univ., Energy Mechatronics Lab.
L
v
dt
diL 0
max0 )(1
)( IdtvL
ti
t
DT
L max0min )(1
)( IdtvL
DTtii
T
DT
L TDL
VII )1(0
minmax
TtDT
0vvL
Analysis
비절연형 DC-DC 컨버터 – Buck-Boost (IV)
iD
t
Imax
Imin
DT T
iSImax
Imin
tDT T
iL
t
Imax
Imin
DT T
전력전자공학
17 / 20
Sungkyunkwan Univ., Energy Mechatronics Lab.
Duty ratio=0.4
Inductance=100uH
Capacitance=202uF
Frequency=100k
Resistor=10hm
Buck-Boost Simulation (CCM Mode)
비절연형 DC-DC 컨버터 – Buck-Boost (V)
전력전자공학
18 / 20
Sungkyunkwan Univ., Energy Mechatronics Lab.
비절연형 DC-DC 컨버터 – Buck-Boost (VI)
ON OFF
Simulation Result
인덕터 전류
스위치 전류
다이오드 전류
전력전자공학
19 / 20
Sungkyunkwan Univ., Energy Mechatronics Lab.
비절연형 DC-DC 컨버터 – Buck-Boost (VII)
Simulation Result
ON OFF
다이오드 전류
커패시터 전류
커패시터 전압 = 출력 전압
전력전자공학
20 / 20
Sungkyunkwan Univ., Energy Mechatronics Lab.
각 Converter 별 Duty 비교
DV
DV
V
VG
i
i
i
V 0
1
Buck mode Boost mode
0.5
0 1
1V
i
VG
V D
Buck 컨버터 Boost 컨버터 Buck-Boost 컨버터
비절연형 DC-DC 컨버터
1
0.8
0.4
0.2
0
Gv
0.2 0.4
0.6
0.6 0.8 1
D
10
8
4
2
0
Gv
0.2 0.4
6
0.6 0.8 1D
0
1V
i
V DG
V D
0 0.2 0.4 0.6 10.8
D
2
4
6
8
10Ideal Gv
Gv
