vacon • 178
Parameters
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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 variation of irradiation.
P3.22.2.1 V
MP
AT
100%
POWER
P3.22.2.2 V
MP
AT
10%
POWER
The Vmp parameters should be obtained from panel characteristics, considering standard tem-
perature and irradiation at 10% and 100% level.
If the second value is not known, subtract 50-60 V from the first value as a rough estimation.
The accuracy of these values is not really critical, because the correction logic can easily compen-
sate 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.
P3.22.2.3 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 P3.22.2.3.
MPPT regulator
The drive tries to get the maximum power from solar panels by keeping the DC voltage at the opti-
mum 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 (V2.3.1) and compared to actual DC voltage (V2.3.10), 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 delay in
response.
P3.22.2.4 P
GAIN
Proportional gain [Hz/V]. If set to 1.000, a variation of 1 V on DC bus voltage causes a variation of
1 Hz on frequency reference
P3.22.2.5 I
GAIN
Integral gain [Hz/Vxs]. If set to 1.000, a variation of 1 V on DC bus voltage causes a variation of 1 Hz
per second on frequency reference.
P3.22.2.6 A
CCELERATION
TIME
Time from minimum to maximum frequency. Used only when solar power is active.
P3.22.2.7 D
ECELERATION
TIME
Time from maximum to minimum frequency. Used only when solar power is active.
MPPT correction parameters
This algorithm changes the DC voltage reference, to compensate temperature variations (usually
slow) and to correct the error in feed-forward curve.
