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EET 423
POWER ELECTRONICS -2
POWER ELECTRONICS 2
Prof R T Kennedy
1
SMPS OPERATION
QUANTIZED POWER/ENERGY TRANSFER
VOLTAGE REGULATION
POWER ELECTRONICS 2
Prof R T Kennedy
2
BASIC COMPONENTS
sw1
Ein
NON-ISOLATED
C
sw2
L
R
sw1
sw2
ISOLATED
SW1 controllable
Ein
T
C
L
R
BJT MOSFET IGBT
SW2 non-controllable (RECTIFIER pn or Schottky)
controllable (MOSFET)
POWER ELECTRONICS 2
Prof R T Kennedy
3
COMPONENT INTERCONNECTIONS
1
2
sw1
C
sw2
Ein
R
L
3
3
POWER ELECTRONICS 2
Prof R T Kennedy
4
SWITCHING CYCLE SUB INTERVALS
L
E in
C
R
a
E in
C
L
R
b
E in
L C
R
c
POWER ELECTRONICS 2
Prof R T Kennedy
5
BASIC TOPOLOGIES & CONSTRAINTS
SWITCH
sw1
12
L
Ein
13
C
R
sw2
sw2
L
E in
sw1
C
R
23
PROBLEM
L
L
L
inrush current
short circuit source
output capacitor
voltage discharge
Sw1
Sw2
ON
OFF
J
OFF
ON
J
OFF
ON
OFF
ON
J
L
YES
YES
YES
NO
N
POWER ELECTRONICS 2
Prof R T Kennedy
6
BASIC-1 BUCK CONVERTER
Ei n
L
sw1
C
sw2
R
Ei n
sw1
on
L
C
R
a
L
Ei n
c
L C
R
Ei n
sw2
on
C
R Vout
POWER ELECTRONICS 2
Prof R T Kennedy
7
BASIC-2 BOOST CONVERTER
sw2
L
L
C
E in
E in
sw1
sw1
on
R
sw2
on
R
b
L
L
E in
E in
C
C
R
C
R
a
POWER ELECTRONICS 2
Prof R T Kennedy
8
BUCK TOPOLOGY TERMINOLOGY
• Step Down Converter
output voltage  input voltage
• Direct Converter
direct energy transfer from input to output (sw1 on)
• Forward Converter
energy transferred forward supply  load (sw1 on)
• Single Ended Converter
common input-output rail
• Non-Isolated Converter
no transformer input – output isolation
POWER ELECTRONICS 2
Prof R T Kennedy
9
BUCK TOPOLOGY TERMINOLOGY
• Step Down Converter
output voltage  input voltage
• Direct Converter
direct energy transfer from input to output (sw1 on)
• Forward Converter
energy transferred forward supply  load (sw1 on)
• Single Ended Converter
common input-output rail
• Non-Isolated Converter
no transformer input – output isolation
POWER ELECTRONICS 2
Prof R T Kennedy
10
BOOST TOPOLOGY TERMINOLOGY
• Step Up Converter
output voltage  input voltage
• Indirect Converter
no direct energy transfer from input to output
• Single Ended Converter
common input-output rail
• Non-Isolated Converter
no transformer input – output isolation
POWER ELECTRONICS 2
Prof R T Kennedy
11
BOOST TOPOLOGY TERMINOLOGY
• Step Up Converter
output voltage  input voltage
• Indirect Converter
no direct energy transfer from input to output
• Single Ended Converter
common input-output rail
• Non-Isolated Converter
no transformer input – output isolation
POWER ELECTRONICS 2
Prof R T Kennedy
12
BUCK-BOOST COMBINED CONVERTER
L
E in
L
E in
C
R
C
R
POWER ELECTRONICS 2
Prof R T Kennedy
13
BUCK-BOOST COMBINED CONVERTER
L
E in
L
E in
C
R
C
R
POWER ELECTRONICS 2
Prof R T Kennedy
14
BUCK-BOOST COMBINED CONVERTER
L
L
E in
C
R
SWITCH
SYNCHRONISATION
POWER ELECTRONICS 2
Prof R T Kennedy
15
BUCK-BOOST COMBINED CONVERTER
L
Ein
sw1
on
C
R
b
L
Ein
C
sw2
on
R
c
POWER ELECTRONICS 2
Prof R T Kennedy
16
BUCK-BOOST COMBINED CONVERTER
Ein
C
L
R Vout
NOTE
VOLTAGE INVERSION
POWER ELECTRONICS 2
Prof R T Kennedy
17
BOOST-BUCK COMBINED CONVERTER
L2
L1
E in
E in
C1
R
C2
R
POWER ELECTRONICS 2
Prof R T Kennedy
18
BOOST-BUCK COMBINED CONVERTER
L2
L1
E in
E in
C1
R
C2
R
POWER ELECTRONICS 2
Prof R T Kennedy
19
BOOST-BUCK COMBINED CONVERTER
L2
L1
E in
C2
C1
SWITCH
R
SYNCHRONISATION
POWER ELECTRONICS 2
Prof R T Kennedy
20
BOOST-BUCK COMBINED CONVERTER
L1
Ein
L2
C1
C2
R Vout
NOTE
VOLTAGE INVERSION
POWER ELECTRONICS 2
Prof R T Kennedy
21
SMPS
TOPOLOGIES
POWER SUPPLIES
SWITCHING
LINEAR
HARD
SERIES SHUNT SWITCHED MODE
SMPS
SOFT
RESONANT
RPS
HYBRID
QRPS
2 BASIC TOPOLOGIES
BOOST
BUCK
BUCK DERIVED
BOOST DERIVED
COMBINED
SEPIC
FORWARD
PUSH PULL
1 or 2 Transistor
BUCK-BOOST
BUCK-BOOST DERIVED BOOST –BUCK DERIVED
BRIDGE
FLYBACK
HALF
BOOST -BUCK
FULL
CUK
1 or 2 Transistor
POWER ELECTRONICS 2
Prof R T Kennedy
22
SMPS
TOPOLOGIES
POWER ELECTRONICS 2
Prof R T Kennedy
23
RECAP SMPS APPLICATIONS
POWER ELECTRONICS 2
Prof R T Kennedy
24
INDUCTOR CURRENT MODES
Imax
Iind
1
2
o
Imin
2
1
CCM
t
Imax
Iind
I
I av  max
2
0
t
BOUNDARY
Imax
Iind
DCM
o
1
2
1
3
t
Prof R T Kennedy
2
3
Imi
n
POWER ELECTRONICS 2
25
BUCK CONVERTER CIRCUIT CURRENTS
Ii n
Ids a IL
Ifwd
IL b Iout
L
IC
Ids
Ei n
Ifwd
C
R Vout
POWER ELECTRONICS 2
Prof R T Kennedy
26
Vgs
BUCK CONVERTER
CIRCUIT CURRENTS
CCM
0
Iout
0
IC
0
IC,av= 0
0
IL
0
IL,av=Iout
0
Ids,av 0
Ids
Iin,av
Iout
IL=Ids+Ifwd
0
0
Ifwd
0
IL=Iout+IC
0
Iout
Ifwd,av
POWER ELECTRONICS 2
Prof R T Kennedy
27
Vgs
BUCK CONVERTER
CIRCUIT CURRENTS
CCM
0
Iout
0
IC
0
IC,av= 0
0
IL
0
IL,av=Iout
0
Ids,av 0
Ids
Iin,av
Iout
IL=Ids+Ifwd
0
0
Ifwd
0
IL=Iout+IC
0
Iout
Ifwd,av
POWER ELECTRONICS 2
Prof R T Kennedy
28
Vgs
Iout
IC
BUCK CONVERTER
CIRCUIT CURRENTS
DCM
0
0
IC,av= 0
0
IL=Iout+IC
IL,av=Iout
IL
0
Ids
Ids,av
Iin,av
0
IL=Ids+Ifwd
Ifwd
Ifwd,av
0
POWER ELECTRONICS 2
Prof R T Kennedy
29
BOOST CONVERTER CIRCUIT CURRENTS
Iin
IL
L
b Iout
IC
Ids
Ei n
Ifwd
a Ifwd
Ids
Ifwd
C
R
Vout
POWER ELECTRONICS 2
Prof R T Kennedy
30
Vg
0
Isout
0
IC
BOOST CONVERTER
CIRCUIT CURRENTS
CCM
IC,av= 0
0
Ifwd=Iout+ IC
IL,av=Iin,av
Ifwd
0
Ifwd,av
Ids,av
Id
s
Iout
IL,av
IL=Ids+ Ifwd
0
IL,av
IL
0
POWER ELECTRONICS 2
Prof R T Kennedy
31
Vg
0
Isout
0
IC
0
Ifwd
BOOST CONVERTER
CIRCUIT CURRENTS
DCM
IC,av= 0
Ifwd=Iout+ IC
Ifwd,av = Iout
0
Id
s
Ids,av
IL=Ids+ Ifwd
0
IL,av = Iin,av
IL
0
Prof R T Kennedy
POWER ELECTRONICS 2
32
WAVEFORM FORMULAE
C
DC- average
0
DC
( 1 - D) T
DT
AC- rms
total- rms
D(1  D)  C
D C
B
C
kC
A B
D
2
A
DC
0
DT
k
2( B  A)
B A
D 2
 D( A  B) 
( A  AB  B 2 )  

3
2


k2
D(1 
)  D2 C
12
2
D 2
( A  AB  B 2 )
3
k2
D(1 
) C
12
(1 - D) T
C
A B
2
y
0
0
y
Y
3

Y
y
12
3

Y
12
POWER ELECTRONICS 2
Prof R T Kennedy
33
WAVEFORM FORMULAE
DC- average
C
D
C
2
AC- rms
D D2

C
3
4
total- rms
D D2

C
3
4
0
D T (1-D) T
POWER ELECTRONICS 2
Prof R T Kennedy
34
TRAPEZOIDAL-SQUAREWAVE
RMS COMPARISON
B
kC
4
 1.155
3
C
A
0
D T (1 - D) T
rms, trap
rms, sq
rms, trap
k2
 1
rms, sq
12
1
2( B  A)
k
B A
C
A B
2
0
2
k
square wave
POWER ELECTRONICS 2
Prof R T Kennedy
1
CCM-DCM boundary
peak  peak ripple
k
2
pulse average
35
PARASITICS
PARASITIC EFFECTS
LOSSY
RESISTIVE
SOURCE
RS
INDUCTOR
rL
MAGNETICS
core loss
winding loss
CAPACITOR
esr
LOSSLESS
CAPACITOR
esl
SEMICONDUCTORS
RECTIFIER
VF
I rev rec
INDUCTOR
TRANSFORMER
leakage L
stray capacitance
TRANSISTOR
ON Loss
SWITCHING loss
BJT /IGBT
ce
BJTV/IGBT
MOSFET
rds,on
MOSFET
Vce
rds,on
turn on
turn on
turn off
turn off
POWER ELECTRONICS 2
Prof R T Kennedy
36
POWER and POWER LOSSES
MOSFET
IM
0

Pmos ,loss
 I M 2  Dmos  rds,on
DmosT
T
IGBT
IM
0
DigbtT
T
BJT
IM
0
I rms 2  rds,on
Pmos ,loss
Pigbt,loss

I av  Vce,on
Pigbt,loss
 I M  Digbt  Vce,on
PBJT ,loss

I av  Vce( sat )
PBJT ,loss
 I M  Dbjt  Vce( sat )
DbjtT
T
POWER ELECTRONICS 2
Prof R T Kennedy
37
POWER and POWER LOSSES
RECTIFIER
IM
0
Prect , loss

Prect , loss
 I M  Drect  V F
DrectT
T
RESISTOR
IM
I av  V F
I rms 2  R
PR, loss

PR, loss
 IM 2  D  R
0
R
DT
T
POWER ELECTRONICS 2
Prof R T Kennedy
38
SYSTEM POWERS and EFFICIENCY
v(t )  i (t )
p (t ) 
Pav
1 T
v(t ) i (t ) dt

T 0

T
T
Pav

0 v(t ) dt  0 i(t ) dt
T
T
Pav

voltage area current area

period
period
Pav

Vav  I av
POWER ELECTRONICS 2
Prof R T Kennedy
39
SYSTEM POWERS and EFFICIENCY
efficiency 
Pout, av
Pin, av

efficiency 
Pin, av  Ploss
Pin, av

Pout, av
Pout, av  Ploss
Vout  I out
Ein  I in, av
POWER ELECTRONICS 2
Prof R T Kennedy
40
VOLTAGE TRANSFER FUNCTION ANALYSIS
• ENERGY BALANCE
• POWER BALANCE
• VOLT-TIME INTEGRAL
POWER ELECTRONICS 2
Prof R T Kennedy
41
FARADAY’S VOLT-TIME INTEGRAL
IM
INDUCTOR CURRENT
Im
current start and finish at same value
0
t
V1
INDUCTOR VOLTAGE
0
t1
t
V2
t2
VL, av

1 T  di 
L
dt
T 0  dt 
VL, av

1 T
L di
T 0
VL, av

L T
I 
T 0
VL, av

L
I 0  IT   0
T
T
EQUAL AREAS
T
0 v(t ) dt
V1  t1
0
 V2  t2
POWER ELECTRONICS 2
Prof R T Kennedy
42
BUCK and BOOST CONVERTERS
VOLTAGE TRANSFER FUNCTIONS
5
BOOST
4.5
Vout
1

1
Ein 1  Dsw1
4
3.5
Vout
Ein
3
2.5
2
1.5
BUCK
1
Vout
 Dsw1  1
Ein
0.5
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Dsw1
Prof R T Kennedy
1
POWER ELECTRONICS 2
43
BUCK-BOOST BOOST- BUCK
CONVERTERS
VOLTAGE TRANSFER FUNCTIONS
1
INVERTED
STEP DOWN (<1)
0
1
2
3
4
Vout
Ein 5
INVERTED
STEP UP (>1)
6
7
8
9
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
1
Dsw1
POWER ELECTRONICS 2
Prof R T Kennedy
44
PRACTICAL SYSTEMS

Vout
Ein

Vout  I out
Ein  I in, av

 I in, av 

 
 I 
Vout
Vout

 efficiency
Ein practical
Ein ideal
POWER ELECTRONICS 2
Prof R T Kennedy
45