ÇUKUROVA UNIVERSITY INSTITUTE OF NATURAL AND APPLIED ...

4. MODELING OF PROPOSED DVR Mustafa İNCİ
N
= V nV
(4.12)
P
V
S
in
=
N
P
in
Where transformer turns ratio is defined as the ratio of secondary winding
turn number to primary winding turn number.
N
N
S
n = (4.13)
P
The voltage across the output inductor L1 is given by
V
L
N
S
= VS
−VO
= −VO
(4.14)
N
P
Assuming a constant output voltage Vo, the voltage across L1 is a constant,
resulting in a linearly increasing current in L1. In the interval when S1, S2 or S3,S4
is closed, the change in current in L1 is
∆I
L
∆t
∆I
L
=
DT
VL
=
L
1
=
L
1 1 1
1
1
⎛ N
⎜
⎝ N
S
P
V
in
−V
O
⎞
⎟
⎠
(4.15)
State 2, First off-period, T2: A first converter off-period, T2, starts when switches,
S1 and S2, are turned off. All primary switches are off. Inductor current, iL1, is freewheeling
through the two parallel branches, D1-D4 and D3-D2, to output. Inductor
current is discharging. Transformer magnetizing current circulates in the transformer
secondary winding and the diodes, D1-D3 and/or D2-D4. The period ends when
switches, S3 and S4 are turned on (Nymand et al., 2010).
⎛ 1 ⎞
T2 = ⎜ − D⎟T
(4.15)
⎝ 2 ⎠
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