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Optimization with Predictive IV and Impedance Matching

 

 

How does Optimization Work?

Predictive IV

Predictive IV uses module behavior statistics in conjunction with Impedance Matching in order to predict the optimum settings for a module to generate its maximum energy. Performance parameters are set locally, which enables real-time response to changing site conditions for the highest operational efficiency. This feature is part of the TS4 universal junction box platform and is found on the TS4-O and TS4-L covers (Optimization and Longer Strings, respectively.)

Predictive IV technology also allows for selective deployment of optimization. TS4-based modules can be selectively placed as needed to utilize more than one feature set within the same PV array. For example, it allows for optimizers to be placed only where modules are shaded, providing a performance boost at a lower cost than full deployment.

The image below shows the output of a string with a single shaded module (measured with an AC meter), both with and without selective deployment of optimization. In this example, 18.5% of lost energy was recovered.

Measurements of selective placement experiment, taken by an AC meter. Greater energy yield with PIV is highly noticeable.

 

Impedance Matching

Impedance matching can be understood with the help of a loose analogy to a water pipe composed of sections of varying diameter. Panels with higher generating capacity, such as the one on the left (150 watts), are like pipe sections with a large diameter; the middle panel, operating at only 50 watts, represents a narrower pipe.

A 50W module will produce less current than a 150W module

 

Connecting panels of varying output in a string is analogous to connecting pipe segments of different diameter—of course the narrow sections will affect the way water flows through the entire structure. Similarly, panels with low generating capacity bring down the efficiency of the entire array. The flow of current through lower generating panels is impaired in two important ways:

  • The weaker panel will have to handle higher current than it is able to, thus resulting in heat dissipation
  • The weaker panel will start to leak, further decreasing the overall power output of the string

Tigo's Impedance Matching technology provides a solution to the problems caused by panel mismatch. Tigo’s patented approach creates a parallel path for current to flow around weak panels, enabling an optimal flow of energy. This bypass tunnel maintains the optimal flow of energy throughout the string.

 

Illustration of bypass tunnel in action

 

System Components

For modules equipped with TS4 junction boxes, the optimization calculations are performed at each module and do not require external communication. PV systems that do not require monitoring or rapid shutdown can use TS4-O or TS4-L to optimize where needed without installing a Cloud Connect or Gateway(s).

For add-on models (ES and 2ES series) as well as the 1st generation smart modules, the Cloud Connect or MMU are needed in order to assist with the sophisticated analysis algorithm that results in each optimizer applying the ideal Impedance Matching Factor (IMF) to ensure best performance in the array.

All data the Cloud Connect (or MMU) receives from Optimizers is stored and used by Tigo to constantly improve and increase performance. It can also be used as a data logger for 3rd party devices, such as inverters, AC meters, and weather stations.

 

For further reading, refer to our Optimization whitepaper below.

 

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