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6F3A4768
5.6.5 Voltage Saturation Restraint Control (VSC)
If the AD voltage/DC voltage ratio becomes excessively large, the current control output of the converter
saturates, which may result in unsteady control. This can be prevented by voltage saturation restraint control
(VSC). The basic operation is to generate D-axis current reference according to the primary voltage reference
value.
Fig. 5.6.5 shows a control block diagram for the voltage saturation restraint control.
Fig. 5.6.5 Voltage Saturation Restraint Control
Control start level
$LMT_VSC
Primary voltage
reference
E1_R
+
+
+
<VSC control>
$VSC_P: Proportional gain
$VSC_I : Integral gain
$FLT_VSC
<Filter>
<Integration>
<Proportion>
Limit
Upper limit:
$LMT_VSC_UL
Lower limit:
$LMT_VSC_LL
<Current limit>
ID_R
4000/100%
1000/100%
-
If PI control output is out of
the limit range, integration
operation of PI control stops.
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