prof r t kennedypower electronics 21 eet 423 power electronics -2
Post on 18-Jan-2018
217 Views
Preview:
DESCRIPTION
TRANSCRIPT
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 11
EET 423 EET 423 POWER ELECTRONICS -2POWER ELECTRONICS -2
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 22
BUCK CONVERTER CIRCUIT BUCK CONVERTER CIRCUIT CURRENTSCURRENTS
Ifwd
Ids
Ei n
Ii n IL
Ids IC Ifwd
C R
L IL
Iout
a
b
Vout
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 33
BUCK CONVERTER CIRCUIT BUCK CONVERTER CIRCUIT VOLTAGESVOLTAGES
Ei n
Vout
Vds a
b
VL,a-b
C
R
L
Vfwd
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 44
SUB INTERVAL EQUIVALENT CIRCUITSSUB INTERVAL EQUIVALENT CIRCUITS
Vds = 0
a
b
VL,a-b= Ein-Vout
Ei n
C R
Vout
L MOSFET
ON
RECTIFIEROFF
Vfwd = -Ein
rds,on
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 55
SUB INTERVAL EQUIVALENT CIRCUITSSUB INTERVAL EQUIVALENT CIRCUITS
Ei n
C R
a
b
Vout Vfwd= 0
Vds = Ein
MOSFET OFF
RECTIFIERON
L
a
b
VL,a-b= -Vout VL,a-b= -Vout a
b
VL,a-b= -Vout
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 66
Ein =Vds +(- Vfwd)
VL + Vout = -Vfwd
0
0
0
0
0
0
Ein
VL
Vout
Vfwd
Vds
0
Vgs
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 77
Ein = Vds + (-Vfwd)0
0
0
0
0
0
Ein
VL
Vout
Vfwd
Vds
0
Vgs
-Vfwd
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 88
SMPS OPERATIONSMPS OPERATION
QUANTIZED POWER/ENERGY TRANSFERQUANTIZED POWER/ENERGY TRANSFER
VOLTAGE REGULATIONVOLTAGE REGULATION
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 99
VOLTAGE TRANSFER FUNCTION ANALYSISVOLTAGE TRANSFER FUNCTION ANALYSIS
• ENERGY BALANCEENERGY BALANCE
• POWER BALANCEPOWER BALANCE
• VOLT-TIME INTEGRALVOLT-TIME INTEGRAL
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 1010
‘‘IDEAL’ IDEAL’ BUCK ANALYSIS CCMBUCK ANALYSIS CCM ENERGY BALANCE APPROACH ENERGY BALANCE APPROACH
INDUCTOR CURRENT
IL,M
IL,m
IL,av = Iout
0
LoutmLML
outLmLML
outmLML
loutmL
LoutML
IIII
IIII
III
III
III
2
2
2
2
2,
2,
,,
,,
,
,
2LI
2LI
outL II
t
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 1111
SUB INTERVAL -1: MOSFET ONSUB INTERVAL -1: MOSFET ON
Ei n
C R
L
OFF
a
b
ON ENERG
YSTORE
D
LoutmLMLL IILIILJ )(21 2
,2
,
INPUTENERG
Y
TDIEtPJ swoutinoninin
LOAD ENERGYfrom source
TDIVtPJ swoutoutonoutsload ,
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 1212
SUB INTERVAL -2: RECTIFIER ONSUB INTERVAL -2: RECTIFIER ON
Ei n
C R
L
ON
a
b
OFF
ENERGYDischarge
NO INPUTENERGY
LOAD ENERGYfrom inductor
LoutLload IILJ ,
TDIVTDIVJ swoutoutfwdoutoutLload )1(,
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 1313
Lloadsload JJenergyloadtotal ,,
))1(()( TDIVTDIV swoutoutswoutout
)(,, TIVJJ outoutLloadsload
swin
out
swoutinoutout
DEV
TDIETIV
energyinputenergyloadtotal
Dsw Ein Vout
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 1414
‘‘IDEAL’ IDEAL’ BUCK ANALYSIS CCMBUCK ANALYSIS CCMPOWER BALANCE APPROACHPOWER BALANCE APPROACH
INPUT CURRENT = MOSFET CURRENT
Iin,av = Ids,av IL,m
IL,M Iout
0
Dsw T
Dfwd T
Iin
t
swin
out
outswinoutout
avininoutout
inout
DEV
IDEIV
IEIV
PP
,
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 1515
FARADAY’S VOLT-TIME INTEGRALFARADAY’S VOLT-TIME INTEGRAL
0
1
1
0,
0,
0,
0,
TavL
TavL
TavL
TavL
IITLV
ITLV
diLT
V
dtdtdiL
TV
INDUCTOR VOLTAGE
V1
t1
0
INDUCTOR CURRENT
t2
V2
0
t
t
I m
I M
T
current start and finish at same value
2211
00)(
tVtV
dttvT
EQUAL AREAS
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 1616
‘‘IDEAL’ IDEAL’ BUCK ANALYSIS CCMBUCK ANALYSIS CCMVOLT-TIME INTEGRAL APPROACHVOLT-TIME INTEGRAL APPROACH
INDUCTOR VOLTAGE
Dsw T
Dfwd T
0
IL
VL
0
Ein -Vout
-Vout t
area B
area A
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 1717
‘‘IDEAL’ IDEAL’ BUCK ANALYSIS CCMBUCK ANALYSIS CCMVOLT-TIME INTEGRAL APPROACHVOLT-TIME INTEGRAL APPROACH
INDUCTOR VOLTAGE
swin
out
swoutswoutin
swoutswoutin
DEV
TDVTDVE
TDVTDVE
BareaAarea
)1()(
0)1()(
0
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 1818
‘‘ideal’ideal’ BUCK CONVERTER CCM BUCK CONVERTER CCMvoltage & current waveformsvoltage & current waveforms
• refer to msw noteletrefer to msw notelet
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 1919
ka
d s
a
k
d s
Vout
0
0
DswT
DfwdT
REDI insw
out
sw
swinswML fL
RDREDI
2)1(1,
sw
swinswmL fL
RDREDI
2)1(1,
inE
outI
outin VE
inE
inswout EDV
Csw
swoutinL I
fLDVEI
)(
LDE
dtI swinriseL )1(,
LED
dtI inswfallL
,
Dfwd = 1-Dsw
0
0
0
0
0
0
0
0
0
Vgs
Iout
Ic
IL
Ids
Ifwd
Ein
Vds
Vfwd
VL
Vout
outI
outI
outswavds IDI ,
2
, 1211
out
Lswoutrmsds I
IDII
inE
outV
outfwdavfwd IDI ,
12,L
rmsCII
2
, 1211
out
Lfwdoutrmsfwd I
IDII
sw
outinswrmsL fL
VEDI12
)(,
Ei n R
Iout
IC
L
C
Ids ILVds
Iout
Ifwd
VfwdVgsfsw
VL
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 2020
INDUCTOR CURRENT WAVEFORMSINDUCTOR CURRENT WAVEFORMS
• CCM or DCM operational modeCCM or DCM operational mode• component current stresscomponent current stress• capacitor ripple currentcapacitor ripple current• output voltage rippleoutput voltage ripple• converter efficiencyconverter efficiency• closed loop regulation performanceclosed loop regulation performance
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 2121
INDUCTOR CURRENT INDUCTOR CURRENT v v INDUCTANCEINDUCTANCE
REDUCTION in L
DswT Dfwd T
0
0
Iout
Ein-Vout
-Vout
VL
IL
t
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 2222
INDUCTOR CURRENT INDUCTOR CURRENT v v INDUCTANCEINDUCTANCE
REDUCTION in L
DswT Dfwd T
0
0
Iout
Ein-Vout
-Vout
VL
IL
t
increased
Isw,max
Ifwd,max
IC,ripple
Vout,ripple
dtdI riseL,
dt
dI fallL,
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 2323
INDUCTOR CURRENTINDUCTOR CURRENT
sw
swinswML
sw
swoutML
sw
swoutoutML
LoutML
fLRD
REDI
fLRD
RVI
fLDV
RVI
III
2)1(1
2)1(1
2)1(
2
,
,
,
,
L
outML
MRVI
211,
RfL
TRL sw
swL
in
outEVM
sw
swinswmL fL
RDRED
I2
)1(1,
L
outmL
MRVI
211,
sw
swswin
sw
swoutL fL
DDEfLDVI
)1()1(
L
outL
MRV
I
1
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 2424
INDUCTOR CURRENTINDUCTOR CURRENT
0
LI
IL
t
LI
LI
Iout
Dsw = 0.2Dsw = 0.5Dsw = 0.8
Dsw > 0.5
Dsw < 0.5
Dsw= 0.5
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 2525
INDUCTOR CURRENTINDUCTOR CURRENT
0
LIIL
t
LI
LI
LDE
dtdI swinriseL )1(,
UPSLOPELDE
dtdI swinfallL ,
DOWNSLOPE
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 2626
INDUCTOR INDUCTOR PEAK-PEAK RIPPLE CURRENTPEAK-PEAK RIPPLE CURRENT
)1( swswn
L DDfI
5.00 1
swD
LI
sw
swswinL fL
DDEI
)1(
max,LI
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 2727
IL
IL
IL
t0
0
0
t
t
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 2828
IL
IL
IL
t0
0
0
t
t
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 2929
IL
IL
IL
t0
0
0
t
t
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 3030
LI
swI
fwdI
outI
MswI ,
rmsswI ,
avswI ,
MfwdI ,rmsfwdI ,
avfwdI ,
swD fwdD
‘‘IDEAL’ BUCK CCM DEVICE CURRENTIDEAL’ BUCK CCM DEVICE CURRENT
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 3131
‘‘IDEAL’ BUCK CCM DEVICE CURRENTIDEAL’ BUCK CCM DEVICE CURRENT
LI
swI
fwdI
outI
MswI ,
rmsswI ,
avswI ,
MfwdI ,rmsfwdI ,
avfwdI ,
swD fwdD
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 3232
‘‘IDEAL’ BUCK CCM TRANSISTOR CURRENTIDEAL’ BUCK CCM TRANSISTOR CURRENT
CCM TRANSISTOR CURRENT IM
sw
swoutfLRD
RV
21
1
L
out MR
V2
11
Iav swout DRV M
RVout
Irms sw
out
sw
swswsw
out DR
VfLRDD
DR
V
22
12)1( M
RVMM
RV out
L
out
2
21
1211
IL
swsw
outfLRD
RV 1
L
out MRV
1
in
outEVM
RfL sw
L
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 3333
‘‘IDEAL’ BUCK CCM RECTIFIER CURRENTIDEAL’ BUCK CCM RECTIFIER CURRENT CCM RECTIFIER CURRENT
IM
sw
fwdoutfLRD
RV
21
L
out MR
V2
11
Iav fwdout DRV M
RVout 1
Irms fwd
out
sw
fwdfwd
out DR
VfLRD
DR
V
23
12
)( MR
VMMR
V out
L
out
2
21
1211
IL
swfwd
outfLR
DRV
L
out MRV
1
avrmsffi
fwdsw
fwd
fwd DfLRD
D1
121
2
M
M1
in
outEV
M RfL sw
L
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 3434
OUTPUT EFFECTSOUTPUT EFFECTS
Ei n
C
L
Vout= 0
s/c
Iin
t0
LE
dtdI inin
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 3535
OUTPUT EFFECTSOUTPUT EFFECTS
Ei n
C
L
VoutEin
o/c
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 3636
POWER - UP EFFECTPOWER - UP EFFECT
Ei n
C
R
Vout
Vc= 0
L
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 3737
POWER - DOWN EFFECTPOWER - DOWN EFFECT
Ei n
C
R
Vout
L
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 3838
CCM-DCM BOUNDARYCCM-DCM BOUNDARY
sw
swcritical
sw
swoutout
Lout
fRDLL
fLDV
RV
II
2)1(
2)1(
2
21 swsw D
RfL
outL II
2out
L II
2
LI
0t
TDsw
outI
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 3939
CCM-DCM BOUNDARYCCM-DCM BOUNDARY
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.050.1
0.150.2
0.250.3
0.350.4
0.450.5
RfL sw
swD
21 swsw D
RfL
boundary
21: swsw D
RfLCCM
21: swsw D
RfLDCM
RfL
tconstimeinductornormalisedT
sw
sw
L
tan
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 4040
CCM-DCM BOUNDARYCCM-DCM BOUNDARY
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.050.1
0.150.2
0.250.3
0.350.4
0.450.5
RfL sw
swD
boundary
CCM
CCM
DCM
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 4141
CCM / DCM determined by
R
CCM-DCM BOUNDARYCCM-DCM BOUNDARYL Dsw fsw
constant
to ensure a desired CCM does not transfer to DCM
specify a minimum load current (maximum R)
avoid open circuit operation
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.050.1
0.150.2
0.250.3
0.350.4
0.450.5
RfL sw
swD
CCM
DCM
INCREASE R‘light loading’
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 4242
CCM / DCM determined by
L
CCM-DCM BOUNDARYCCM-DCM BOUNDARYR Dsw fsw
constant
to ensure a desired CCM does not transfer to DCM
design for CMM at lowest inductance
including L v I
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.050.1
0.150.2
0.250.3
0.350.4
0.450.5
RfL sw
swD
CCM
DCM
DECREASE L
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 4343
CCM / DCM determined by
fsw
CCM-DCM BOUNDARYCCM-DCM BOUNDARYR Dsw fsw
constant
to ensure a desired CCM does not transfer to DCM
design for CMM at lowest frequency
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.050.1
0.150.2
0.250.3
0.350.4
0.450.5
RfL sw
swD
CCM
DCM
DECREASE fsw
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 4444
CCM / DCM determined by
Dsw
CCM-DCM BOUNDARYCCM-DCM BOUNDARYL R fsw
constant
to ensure a desired CCM does not transfer to DCM
design for CMM at lowest duty cycle
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.050.1
0.150.2
0.250.3
0.350.4
0.450.5
RfL sw
swD
CCM
DCM
DECREASE Dsw
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 4545
LINE & LOAD LINE & LOAD REGULATIONREGULATION
RfL sw
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
in
outEVM
swD
DCM
CCMM
DCMM
swD
CCM
DCMM
Prof R T KennedyProf R T Kennedy POWER ELECTRONICS 2POWER ELECTRONICS 2 4646
LINE & LOAD LINE & LOAD REGULATIONREGULATION
RfL sw
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
in
outEVM
swD
DCM
CCM
ccmswD ,dcmswD ,
M
top related