A short perturb period (P3.22.2.8) makes the
regulation faster, assuming that the PI gains are not
too low (power variation has to complete within the
period).
The correction term can be monitored (V2.2), to help
the tuning of reference feed-forward. When the
panels temperature is close to standard, 25 °C, the
correction term should result small (+/- 20 to 30 V).
The correction decreases towards negative maximum
as temperature increases.
The correction term increases towards positive
maximum in case of low temperature.
If something different is observed, feed-forward
values should be improved.
P3.22.2.10 P&O power variation
P3.22.2.10 determines the variation in motor power,
above which iteration of voltage reference change
continues in the same direction.
Small value leads to a regulation very close to the
maximum of the panel curve, with possible instability.
Higher values lead to a more stable point, but with
lower efficiency.
P&O in local max points
A panel with partial irradiation, or somehow defective,
could cause a discontinuity on the power/voltage
curve of the array. In this situation the basic P&O
logic (perturb and observe) could lead to a local
maximum point, that is not corresponding to
maximum available power.
50 100 150 200
2
1.5
1
0.5
0
2.5
250
3
0
x10
4
P
MAX1
P
MAX2
P
MAX3
A
B
C
D
D
MPPT
164
English (GB)
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