Upload
others
View
17
Download
0
Embed Size (px)
Citation preview
IE
Switch mode power supply
230 Vac 50 Hz
15 Vdc
Low frequency (50 Hz)
rectifying High frequency AC generation
Isolation, Adopting voltage
Stabilize DC-voltage
High frequency rectifying
IE
Switch mode power supply Transformer definition
V1 N1 N2 V2
=
=
=
2
2
1
2
1
1
2
2
1
2
1
2
1
NN
ZZ
NN
II
NN
VV
IE
Switch mode power supply Transformer
φm φ1
φ2
IE
Switch mode power supply Transformer equivalent circuit
reduced to one side
φ1 φ2
φM
IE
Forward converter
vC Rload
VDc Cdc
vS
C D2
D1 D3
Z
VD1
L
S
N1 N2
IE
Forward converter at turn on
vC Rload
VDc Cdc
vS
C D2
D1 D3
Z
VD1
L
N1 N2
Turn on
IE
Forward converter at turn off
vC Rload
VDc Cdc
vS
C D2
D1 D3
Z
VD1
L
N1 N2
Turn off
IE
Fly-back converter vD
vC
VDc Cdc
vS
C
IE
Fly-back converter at turn on
vD
vC
VDc Cdc
vS
C
Turn on
IE
Fly-back converter at turn off
vD
vC
VDc Cdc
vS
C
Turn off
IE
Fly-back converter Transformer snubber
vC C
IE
Fly-back converter Switch snubber
vC C
IE
Fly-back converter Diode snubber
vC C
IE
Fly-back converter RCD snubber at turn off
Leakage inductance requires a freewheeling path
IE
Switch mode power supply Transformer
φm φ1
φ2
IE
Fly-back converter RCD snubber at turn on
Transformer leakage inductance requires a freewheeling path. Design of capacitor C i based on voltage over C
C
stUCtIUCQechtoTime
FC
VUHL
AIExample
UILCWWequalEnergies
UCWCinenergyElectric
ILWenergyMagneticUvoltagecapacitorAllowed
em
e
m
µ
µ
µ
6610
151044arg
44151010
1510010
6
24
2
221
221
<⋅⋅
=⇒⋅=⋅⇒⋅=
=
⋅=
=∆==
∆
⋅=⇒=
∆⋅⋅=
⋅⋅=
∆
−
−
IE
Fly-back converter RC snubber over main switch
Needed due to fast switching and stray inductance
IE
Fly-back converter Diode snubber
vC C
vC C
IE
Fly-back converter Rectifier
IE
Fly-back converter Common mode filter
IE
Fly-back converter. Inrush current limitation
T-
IE
Fly-back converter Differential mode filter
T-