Vacon 20 CP/X, Applications Manual

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vacon • 77 Parameter description
4
4.13.2.1 MPPT feed-forward parameters
MPP feed-forward controller continuously changes the reference from Vmp@10% to
Vmp@100%, according to actual motor power. The main purpose of this term is to follow vari-
ation of irradiation.
P14.5 V
MP AT
100%
POWER
P14.6 V
MP AT
10%
POWER
The Vmp parameters should be obtained from panel characteristics, considering standard
temperature and irradiation at 10% and 100% level.
If the second value is not known, subtract 50-60V from the first value as a rough estimation.
The accuracy of these values is not really critical, because the correction logic can easily com-
pensate error of some tens of volts. It is better to set values possibly higher than the real ones,
and let the correction decrease the voltage reference, to get maximum power.
P.14.7 P
ANEL
/M
OTOR RATIO
In case the solar panels have less maximum power than the motor, a value lower than 100%
should be set in P14.7.
4.13.2.2 MPPT regulator
The drive tries to get the maximum power from solar panels by keeping the DC voltage at the
optimum point (Max Power Point).
There is a PI regulator that changes the internal frequency reference, so that the power sent
to the motor keeps the panels working on MPP.
The voltage reference can be monitored (V2.1) and compared to actual DC voltage (V1.9), to
check the effect of gain tuning.
Continuous, low amplitude and high frequency oscillations mean gains too high.
Ramp times are meant to smooth the output frequency, but without introducing significant de-
lay in response.
P14.8 P
GAIN
Proportional gain [Hz/V]. If set to 1.000, a variation of 1V on DC bus voltage causes a variation
of 1Hz on frequency reference
P14.9 I
GAIN
Integral gain [Hz/Vxs]. If set to 1.000, a variation of 1V on DC bus voltage causes a variation of
1Hz per second on frequency reference.
P14.10 A
CCELERATION TIME
Time from minimum to maximum frequency. Used only when solar power is active.
P14.11 D
ECELERATION TIME
Time from maximum to minimum frequency. Used only when solar power is active.