Nomura MPPTs have not been working, so an alternative is being investigated.

They basically sold us an IC with its application circuit on the board, so creating our own custom MPPTs is more desirable.

On solar sense, there is an MPPT_Interface schematic sheet. I think it would make sense to move the isolated components to the MPPT (the buffer could be removed in that case).

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Purpose

A maximum power point tracker is used to extract the maximum amount of power from our solar panels. As conditions change, the optimal load characteristic to maximize power transfer changes. Since we cannot constantly change our load impedance (the battery), a DCDC converter is used to transform the impedance of the load. An algorithm adjusts the duty cycle of the DCDC converter to keep the panel at it’s optimal operating point.

We wish to stop giving MPPT manufacturers a lot of money, so we are trying to make our own. These should be interoperable with the current Nomura MPPTs since the rest of our system is designed for their use already.

Requirements

At least 7A, 10V-30V input
At least 40V output
Analog control (FW doesn’t have bandwidth)
Series operation and interoperability with SPV1020 (Nomura)

MPPT Control

Papers of interest

P&O used by Tokai

Buck-Boost Type MPPT Circuit Suitable for Photovoltaic Generation of Vehicle Installation

Pros	Cons
No multiplier Input voltage regulation	No obvious way to limit the output voltage Relatively large # of external components Large input perturbations (2-3%)

No multiplier P&O

Load current based analog MPPT controller for PV solar systems

Pros	Cons
No multiplier Input voltage regulation	No obvious way to limit the output voltage Relatively large # of external components Large input perturbations (2-3%)