SolarEdge and Infineon extend 800VDC protection collaboration

SolarEdge and Infineon Technologies have extended their collaboration on high-voltage DC data-centre infrastructure into solid-state circuit breakers, addressing the protection layer between medium-voltage conversion equipment and increasingly power-dense AI computing racks.

SolarEdge is leading development of the solid-state circuit breaker, or SSCB, with Infineon providing its CoolSiC silicon-carbide JFET technology for the protection devices. The companies are targeting 800VDC distribution architectures being developed for AI and hyperscale facilities, where fault isolation becomes more demanding as power density and DC bus voltage increase.

The technical problem begins with a fundamental difference between AC and DC circuits. Alternating current naturally crosses zero during each cycle, providing a point at which an electrical arc can be extinguished as mechanical breaker contacts separate. A DC circuit has no equivalent natural current zero, making interruption and arc control more difficult.

SolarEdge says the SSCB is designed to interrupt faults within a few microseconds without mechanical contacts. Semiconductor switching can therefore react considerably faster than a conventional electromechanical breaker, reducing the period for which fault current is allowed to propagate through high-value downstream equipment.

Speed alone is not sufficient. Protection inside a large data centre also needs selectivity, so a local fault can be isolated without unnecessarily disconnecting a much larger block of computing capacity. That requires coordination between protection devices throughout the DC distribution chain as well as accurate detection of the fault itself.

Shuki Nir, Chief Executive Officer of SolarEdge, said: “High-density AI infrastructure at 800 VDC demands uncompromising efficiency and protection.” The engineering objective is to add fast fault isolation without eroding the efficiency that makes higher-voltage DC distribution attractive in the first place.

The new work builds on a collaboration announced in November 2025 around SolarEdge’s solid-state transformer platform. The companies are jointly developing and validating modular SST building blocks rated between 2MW and 5MW, using Infineon silicon-carbide switching technology.

The SST is designed to convert directly from a 13.8–34.5kV medium-voltage AC supply to an 800–1500VDC output with efficiency above 99%. Combining several traditional conversion stages into a single solid-state platform is intended to reduce physical footprint, weight, and conversion losses between the incoming grid supply and the internal DC distribution system.

The SSCB addresses the next section of that electrical chain. Efficient conversion at the grid interface is of limited use if the downstream DC bus cannot be segmented and protected appropriately. A practical grid-to-rack system needs breakers capable of isolating distribution branches, coordinating faults, and protecting equipment at the power levels envisaged for future AI facilities.

Infineon’s CoolSiC JFET devices are intended to provide the semiconductor switching element. Silicon carbide has established roles in high-efficiency power conversion because its material characteristics can support high voltage, switching frequency, and temperature while reducing losses compared with conventional silicon in appropriate applications.

Protection presents a different operating duty from a converter. Current must pass through the semiconductor continuously during normal operation, so conduction loss and thermal behaviour matter before any fault occurs. When a fault is detected, the same device has to interrupt current rapidly and survive the electrical stress associated with the event.

This produces trade-offs that do not exist to the same degree in a mechanical breaker. Semiconductor area, cooling, redundancy, control electronics, isolation, failure behaviour, and cost all influence whether solid-state protection can be deployed economically across large numbers of distribution branches.

The attraction grows as rack power increases. For a given amount of power, moving to a higher distribution voltage reduces current, which can reduce conductor requirements and resistive loss. The accompanying protection equipment must still withstand the higher bus voltage and clear faults quickly enough to protect the computing loads behind it.

SolarEdge describes its wider programme as an 800VDC powertrain extending from the medium-voltage grid connection through conversion, distribution, protection, and ultimately the compute rack. The latest announcement fills a specific gap in that chain rather than introducing another general proposal for DC data-centre architecture.

That distinction also separates the development from broader industry work around hybrid AC/DC systems. The immediate subject is a particular protection technology — an SSCB using Infineon SiC JFET devices — intended for the distribution layer between SolarEdge’s SST platform and high-density compute equipment.

The companies have not yet disclosed several specifications needed to judge the eventual commercial product. Breaker current ratings, interrupting capacity, on-state losses, package dimensions, thermal design, redundancy strategy, price, and commercial availability remain unspecified.

Those details will matter when system designers compare semiconductor protection with alternative breaker architectures. A device capable of microsecond interruption still has to operate efficiently for thousands of hours under normal load and integrate with the wider data-centre protection scheme.

Andreas Weisl, Executive Vice President and Chief Sales Officer of Industrial & Infrastructure at Infineon, said the collaboration is intended to deliver faster and more robust power distribution for AI infrastructure. Its success will ultimately depend on how the semiconductor devices perform as part of a complete protection architecture rather than in isolation.

There is a further question around standardisation. An 800VDC ecosystem will need consistent expectations for voltage tolerance, interfaces, protection coordination, safety, and rack-level distribution if equipment from different manufacturers is to be deployed at scale rather than through proprietary electrical islands.

SolarEdge and Infineon have now identified conversion and protection technologies for two major parts of the proposed grid-to-rack chain. The SST targets direct medium-voltage conversion at greater than 99% efficiency, while the new SSCB programme targets fault interruption within microseconds. The next test is whether those capabilities can be turned into repeatable, specified hardware for multi-megawatt AI facilities.