Some curiosities about optimizers that I can't seem to find info on

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    Gary Hethcoat

    Hi Matthew,

    Tigo is a buck-only architecture.  Our optimizers will buck (lower voltage and boost current) on underperforming PV modules.  This is the same action for any kind of mismatch in the string(s).  We try to keep the current the same across the string by bucking.  For the case you mention where you have different length strings in parallel, say a string of 12 and a string of 10 in parallel.  If you have optimizers on all panels, the optimizers on the longer string will buck the voltage down to match the other string, and you will get the full power available due to the boosted current on the longer string.

    We have a white paper on Optimization in the "Technical Documentation" section of our Downloads area:

    • DC Optimization with Tigo will normally allow you to reclaim an average of 36% of power lost due to mismatch.  Mismatch can be caused by shading, soiling, clouds, snow and differential degradation, among other things.  So for example, if you are losing 100 kWH of energy to mismatch in a year, you can expect to gain about 36 kWH of that energy back through optimization.  That 36% figure comes from an NREL paper, “Partial Shading Assessment of Photovoltaic Installations via Module-Level Monitoring

    See also:

    Hope this helps!

    Gary

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