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4. MODELING OF PROPOSED DVR Mustafa İNCİ
In proposed system, and is determined to compensate voltage sag
of 35% in (4.3):
2
V dc , min
= 11kV
× 0.4 ≅ 1. 572kV
(4.3)
2 3
DC capacitor voltage V
DC
is determined as 1700 V; equivalent DC capacitor
value is calculated as 25 mF.
4.2.2. Design of Inverter Filter
There are several types of filters. The simplest variant is filter inductor
connected to the inverter's output. But also combinations with capacitors like LC or
LCL can be used. The LC type inverter-side filter is used in this study and the
equivalent circuit is depicted in Figure 4.4. It is second order filter and it has better
damping behaviuor than L-filter. This simple configuration is easy to design and it
works mostly without problems. The second order filter provides 12 dB per octave of
attenuation after the cut-off frequency f 0
, it has no gain before f 0
, but it presents a
peaking at the resonant frequency f 0
(Lettl et al., 2011, Köroğlu, 2012).
Figure 4.4. Equivalent Circuit for Inverter Side Filter
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