SolidUltra raises €3M with Watt & Well for 800 VDC solid-state transformers

SolidUltra, a company based in Massy, France, has announced €3 million in funding to develop a modular solid-state transformer that takes medium-voltage grid power directly to 800 VDC for data centres. The news came on 9 November 2026 in a release posted on the news page of Watt & Well, the French power-electronics maker that backs the venture.

The company

According to the release, SolidUltra was incorporated in June 2026, and the money was raised in the three months that followed. The French legal notice on its website lists the company as SolidUltra SAS, with its registered office at 129 avenue de Paris in Massy. The release names four co-founders: chief executive Raul Iglesias, Alain Rouault, chief business officer Romain Beaume and, as a company, Watt & Well. Watt & Well describes itself as a company founded in 2008 that designs and manufactures high-performance power electronics.

The release says the funding will go to product development, engineering, industrialisation and early work with customers.

The technology

The release describes a conventional data-centre power chain as a low-frequency transformer and then multiple further conversion steps. SolidUltra says its transformer replaces that chain with a single conversion stage from the medium-voltage grid to 800 VDC. On its website the company says the design is built from a 100 kW cell, with the cells wired serially on the medium-voltage side and in parallel at the DC side, using automotive-grade silicon carbide devices. The release says systems scale upward from 300 kW, reaching 10 MW or more.

All performance figures are the company's own targets and claims. The release gives a target of 98.5% efficiency, with losses three times lower and equipment four times smaller than conventional designs. The website puts grid-to-DC efficiency above 98%, against about 92% for a transformer followed by a rectifier. The release also says modules that can be swapped in the field within 15 minutes are meant to give 99.999% availability, while the website describes redundant cells arranged as N+k. On time to power, the release speaks of weeks rather than years; the website says days.

Plans and status

The company site marks the product as in development. SolidUltra says it is talking selectively with data-centre operators, hyperscalers and other strategic partners ahead of first deployments, and the release says it aims for a commercial launch in 2028. By 2032, according to the release, the company aims to have delivered 10,000 modular systems, roughly 1 GW of installed capacity in total.

The release says SolidUltra's development plan follows the industry shift to 800 VDC, which it links to a move NVIDIA has announced for coming AI data-centre generations. Iglesias is quoted as saying that racks heading to megawatt-level power call for a rethink of how power is converted and then delivered within facilities.