TS4-Yellow, shades on one of two parallel strings in same array



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    Gary Hethcoat Community Moderator
    Early Adopter

    Hi Kalle,

    Tigo optimizers use a buck-only architecture.  This means that each TS4 on an underperforming module will lower voltage and boost current.  The goal is to keep the current constant across the string.  For two strings in parallel, first of all these two strings have to be fully optimized, meaning an optimizer on all modules in both strings.  If this is the case, and one string is shaded, then the optimizers will still buck.  Current will flow from all modules and overall voltage will drop slightly.  As we know voltage will always equalize in each component of a parallel circuit.  In the end -- all modules will contribute to the power output of the array.  If you want to understand buck/boost better just google "buck converter", there is a lot of information available.  You can also read more in the "Technical Documentation" section of our Download center, in our "Whitepaper - Optimization with Impedance Matching and Predictive IV".  Hope this helps.