Programming instructions

Boost Converter
 National Instruments Corporation 13-7 Multisim Component Reference Guide
13.5.1 Characteristic Equations
The averaging DC and large-signal characteristics of a Boost converter are given by the
following sets of equations:
in which
I
LL
is governed by:
where
D = duty ratio of the switching device.
For the DCM:
For the critical condition between the CCM and the DCM of operations:
For the CCM:
The averaging behavior governed by the above equations is modeled using the built-in
Multisim analog behavioral modeling components. The AC small-signal model is
automatically computed inside the program.
()
II I I
III I
iLLLDL
D
DD
LL LD
D
DD
L
=+=
+
=
+
=
+
∗0
2
2
2
2
[]
I
L
DV DV V dtLL i i
t
=∗−−
∫
1
20
0
()
()
DD
V
VV
V
I
DD D
LF
V
i
i
l
LD
s
i
2
0
2
0
2
=∗
−
=
=
+
∗∗
∗
DD
II VD
LF
LD Lcrit i
s
2
1
1
2
=−
==∗∗
∗∗
()
DD
VDVDVV
II I
Lii i
LLcritLL
2
20
1=−
=− −
=+
ComponentRef.book Page 7 Thursday, December 7, 2006 10:12 AM