Inverter protection system causes permanent short circuit in less than 1 millisecond – SPE

by pv magazine Germany.

A joint research project between the Fraunhofer Institute for Microstructure of Materials and Systems IMWS, Infineon Bipolar and the Technical University of Dresden has developed a semiconductor-based protection concept tailored to the specific requirements of renewable energy systems.

It is capable of generating a short circuit in less than one millisecond that remains permanently intact during the fault. The mechanism used a combination of power switches and semiconductors to quickly and permanently generate a targeted short circuit in the event of a fault and thus protect the components against overcurrent.

This outperforms currently available trip devices designed for conventional power generation systems, which require a trip time of up to 100 milliseconds.

“This is an important basis for new power electronics solutions that enable better grid connection of renewable energy,” said Carola Klute, who led the sub-project ‘Material Diagnostics and Reliability Analysis’ at Fraunhofer IMWS in the ‘GreenGridGuard’ project.

The project partners developed the security systems through testing different demonstrator design variants, which were evaluated over the two-year project period. A chip structure with a sturdy connection on the anode side between a thick carrier disk and a loosely mounted contact disk on the cathode side proved to be particularly effective. This variant was then further developed to optimize the short-circuit effectiveness of the component.

“During the project we were able to develop an accurate understanding of the microstructural and material mechanical mechanisms at work in the components and systems to be used,” said Klute. “We were also able to contribute our expertise to the individual development of microscale test procedures for different material systems, as well as to the evaluation of thermomechanical stresses.”

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