Independent MPP trackers

An MPP tracker controls how much power an inverter draws so that the PV field stays as close as possible to its maximum power point, which shifts with irradiance and module temperature. An inverter with independent MPP trackers has several PV input sections, and each section runs its own MPP tracker. A multi-string inverter of this kind tracks individual strings separately, like several string inverters, while keeping the lower specific cost of a central inverter. Separate tracking is useful when part of the array is shaded or when strings face different tilts or azimuths, and it gives more flexibility in array layout. Some inverters let you combine the trackers into one zone, for example when there is an odd number of strings. Others can only run in independent mode, and some offer a menu setting to turn multiple MPPT on or off. In independent mode, treat each zone like a separate inverter: balance the strings between zones and do DC/AC ratio sizing per zone. Wiring every string to one zone can leave much of the inverter's capacity unused. For surge protection, plan an SPD or SPD combination for each tracker input, not one SPD on a combined string bus. Datasheets list the number of MPP trackers. Large central-style units often have just one, while many string inverters have two or three.

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• sentence 7: support check: partial - Passage says to plan an SPD for each input on multi-tracker inverters, but the 'not one SPD on a combined string bus' contrast is only stated for single-tracker inverters, and fused strings use a common SPD after fuses.
• sentence 8: support check: partial - Datasheets show 1 MPPT for large units and 2–3 for string inverters, but 'datasheets list the number' and 'often/many' generalizations are inferred from a few examples. -->