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Is an MPPT controller just basically a buck/boost converter with extras?

KevinJones

Jun 19, 2022
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It seems to me that a buck/boost converter would provide the optimal power available to the load. The current to the load will always be a function the target voltage (eg 13.2V) and the load impedance. Whether the PV is above or below the target voltage, the converter will always be trying to supply the needed current at the output by drawing the whatever current from the PV to attempt to maintain Pout = Pin (limited of course by the maximum current available from the PV.)

So if you are strictly/only interested in maintaining the maximum power point, would not a buck/boost converter work for that?
 
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Harald Kapp

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The current to the load will always be a function the target voltage (eg 13.2V) and the load impedance.
Right.

An MPPT controller isn't designed to control the power to the load. The design goal for an MPPT controller is to maximize the power drawn from the source, usually a photovoltaic (PV) cell or array of cells.. Since you cannot control the power drawn from the source and the power delivered to the load independently, a MPPT controller can only work correctly with an intermediate buffer/storage aka battery. The controller them maximizes the power drawn from the PV cell to charge the battery whereas the load draws power from the battery as it requires. This can be more or less than the power delivered by the PV cell.
 

CircutScoper

Mar 29, 2022
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Right.

An MPPT controller isn't designed to control the power to the load. The design goal for an MPPT controller is to maximize the power drawn from the source, usually a photovoltaic (PV) cell or array of cells.. Since you cannot control the power drawn from the source and the power delivered to the load independently, a MPPT controller can only work correctly with an intermediate buffer/storage aka battery. The controller them maximizes the power drawn from the PV cell to charge the battery whereas the load draws power from the battery as it requires. This can be more or less than the power delivered by the PV cell.

Excellent explanation! Here's a simple example of an analog MPPT battery charger.

https://www.mikrocontroller.net/attachment/74140/2IFD_MPPT_.pdf
 
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