What is TMEIC's '3rd-Generation PV Inverter'? (1) (page 3)

With advantages of both central-, string-type PV inverters

2019/08/17 17:45
Kenji Kaneko, Nikkei BP Intelligence Group, CleanTech Labo
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Flexibility and scalability added

Many responses from users point out the fact that string-type PV inverters have an advantage in terms of flexibility and scalability compared with central-type PV inverters, according to TMEIC. Because string-type PV inverters feature small capacity, the total output can be changed flexibly by adjusting the number of PV inverters of the same model, which is convenient to add to and expand the equipment.

In contrast, in the case of central-type large-capacity PV inverters, the models vary depending on the output, even if they belong to the same series. In Japan, when the PV inverter model is altered, "the certification needs to be renewed" even if the output to the grid remains the same, entailing increased restrictions in capacity for expanding the existing PV inverter or adding modules.

The new models incorporated the "modular system" to solve the issues of central-type PV inverters. The total output can be increased without changing the PV inverter models by changing the project, for example, from installing four 750kW modules (totaling 3MW) to six 4.5MW modules (Fig. 3).

Fig. 3: Example of structure consisting of six PV inverter modules (source: TMEIC)

In other words, "cost reduction by capacity increase," the advantage of central-type PV inverters, and "flexibility and scalability," the features of string-type PV inverters, were realized at the same time by incorporating the "modular system."

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