APS 6RL Series, Operation Manual

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6RL SERIES OPERATION MANUAL
SECTION 6: FRONT PANEL OPERATION
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2018 by Adaptive Power Systems, Inc. (APS) • All Rights Reserved • No reproduction without written authorization from APS.
6RL Series Regenerative DC Load Operation Manual Page 109 of 204
6.11 MPP Tracking Function
MPP stands for the maximum power point (see
principle view to the right) on the power curve
of solar panels. Solar inverters, when connected
to such panels, constantly track this MPP once
found.
The electronic load simulates this behavior
using a function. This can be used to test even
huge solar panels without having to connect a
usually big solar inverter device, which also
requires to have a load connected to its AC
output. Furthermore, all MPP tracking related
parameters of the load can be adjusted making
it more flexible than an inverter with its limited
DC input range.
For evaluation and analysis purposes, the load
can also record measured data, i.e. DC input
values such as actual voltage, current or power,
to USB thumb drive or provide them for reading
via digital interface.
The MPP tracking function offers four modes. Unlike with other functions or general use of
the unit, values for the MPP tracking function can only be entered by direct input via the
touch screen.
6.11.1 Mode MPP1
This mode is also called “find MPP”. It is the simplest option to have the electronic load find
the MPP of a connected solar panel. It requires setting only three parameters. Value UOC is
necessary, because it helps to find the MPP quicker as if the load would start at 0 V or
maximum voltage. Actually, it would start at a voltage level slightly above UOC.
ISC is used as an upper limit for the current, so the load will not try to draw more current
than the panel is specified for.
Following parameters can be configured for tracking mode MPP1:
Value Range Description
UOC 0...Nominal value of U Voltage of the solar panel when unloaded, taken from the panel specs
ISC
0...Nominal value of I Short-circuit current, max. specified current of the solar panel
Δt 5 ms...65535 ms Interval for measuring U and I during the process of finding the MPP