ÇUKUROVA UNIVERSITY INSTITUTE OF NATURAL AND APPLIED ...

3. FUNDAMENTALS OF DVR Mustafa İNCİ
because there is now an additional flexibility in the design introduced by the factor
k
c
. For a given
k
i
, the value of
k
c
can be chosen such that
k k >> r and a
corresponding increase in the real part of the complex poles is obtained. Thus the
damping level can be increased with an increase of the capacitor current gain
(Vilathgamuwa et al., 2006).
The resulting system can be seen to have the natural damping frequency ω
nncv
i
c
f
r + n r + n r + nk k k r
1
2 2
l t f i c v l 1+
nk k k
ω
nncv
=
≈
== 1+
nk k k . (3.27)
i c v
2
i c v
( rl
+ n rt
) Lf
C
f
Lf
C
f
Lf
C
f
The natural damping frequency of the closed loop system is therefore
approximately
1 + nk k k times filter resonance frequency(Vilathgamuwa et al.,
i
c
v
2002).
System damping and stability margin can be improved by properly selecting
the gains k
c
and k
v
. These gains are determined for a given design specification by
deriving transfer function between load and the reference voltage. Further analysis
reveals that the increase of current gain
tends to increase the damping level while
the increase of voltage gain k
v
, tends to decrease it. As the feed forward gain
presents only in the numerator of the transfer function it does not contribute to
improve system damping and stability margin. However it can be independently
adjusted to decrease steady state error of compensated load voltage. However it can
be independently adjusted to decrease steady state error of compensated load voltage
(Vilathgamuwa et al., 2006).
k
f
,
3.3.6. Gate Signal Generation
Gate signals are used to control of the electrical switches in inverter. The rms
value of output voltage in inverter is controlled by turning the solid-state devices.
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