Epever Tracer-AN Series, User Manual

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4
The MPPT algorithm of our company continuously compares and adjusts the
operating points to attempt to locate the maximum power point of the array.
The tracking process is fully automatic and does not need user adjustment.
As the Figure 1-2, the curve is the characteristic curve of the array, the MPPT
technology will boost the battery charge current through tracking the MPP.
Assuming 100% conversion efficiency of the solar system, in that way, the
following formula is established:
Normally, the V
Mpp
is always higher than V
Bat
, Due to the principle of
conservation of energy, the I
Bat
is always higher than I
PV
. The greater the
discrepancy between V
Mpp
&V
Bat,
, the greater the discrepancy between I
PV
& I
Bat
.
The greater the discrepancy between array and battery, the bigger reduction of
the conversion efficiency of the system,
thus the controller‟s conversion
efficiency is particularly important in the PV system.
Figure 1-2 is the maximum power point curve, the shaded area is charging
range of traditional solar charge controller (PWM Charging Mode), it can
obviously diagnose that the MPPT mode can improve the usage of the solar
energy resource. According to our test, the MPPT controller can raise 20%-30%
efficiency compared to the PWM controller. (Value may be fluctuant due to the
influence of the ambient circumstance and energy loss.)
Figure 1-2 Maximum Power Point Curve
In actual application, as shading from cloud, tree and snow, the panel may
Input power (P
PV
)= Output power (P
Bat
)
Input voltage (V
Mpp
) *input current (I
PV
) =Battery voltage (V
Bat
) *battery current (I
Bat
)