It seems like the 1890’s again!
Why?
Back then a debate was raging between alternating current (AC) and direct current (DC) systems as the choice for America’s electric grid. This was a pivotal moment in the history of electricity as Nikola Tesla was championing AC power that oscillates and Thomas Edison was championing DC, which flows steadily in one direction.
AC power won because of the ability to transform AC to high voltages to transmit long distances, which was not available for DC voltage. Higher voltage means lower current, lower voltage means higher current, and lower current means much smaller wires are needed. For example, running high voltage (35 kV) AC power lines long distance may be only 1 inch (2.54 cm) thick, but running them at low voltage means they would be about 6 feet (183 cm) thick, which is not only impractical, it’s impossible!
This brings us to the modern day issue, which is the fast-moving rack power densities for accelerated compute platforms like the NVIDIA GB300 NVL72 that runs 72 GPUs in parallel at 142 kW per rack. Power must be transformed from the utility, most likely around 35kV down to 12V into the server chassis. The two main power distribution approaches feeding into the servers today are 400V 3 Phase AC and 48 VDC to the rack. Both of these approaches become difficult at 200 kW per rack and impossible at 400 kW per rack, which correlate with the NVIDIA Kyber and NVIDIA Rubin Ultra platforms.
At GTC 2025, NVIDIA exhibited an 800 VDC sidecar PSU (power supply unit) to power 576 of the Rubin Ultra GPUs in a single Kyber rack.
The benefits of 800 VDC architecture
Due to the laws of physics, 800 VDC is necessary for single IT racks 400kW and up to 1 MW! The Rubin Ultra GPUs in a single Kyber rack will begin shipping in 2027. Schneider Electric will have its sidecar in the market well before the release of the Rubin Ultra’s. The Schneider sidecar technical specifications and reference design will also be available to engineers and data center operators well in advance to plan for deployment.
This 800 VDC architecture solves many problems:
- Space limitations – smaller cables and busbars provide connection flexibility
- Reduced copper usage – weight and cost savings
- Higher efficiency – reduced thermal losses
With a single-step AC/DC conversion, there are fewer transformer losses and a more direct power flow. There is also reduced electrical complexity and maintenance and management needs. DC power also brings in the use of diodes and overcurrent circuit protection, which are extremely efficient and reliable.
Schneider Electric’s 800VDC sidecar not only aligns with emerging standards from NVIDIA, it supports Google, Meta, and others. We plan to offer advanced functionality “live swap” capabilities to dramatically simplify maintenance and reduce repair time.
Our commitment to supporting 800 VDC power
At Schneider Electric, we actively collaborate with NVIDIA and are committed to releasing power and cooling in advance of every future NVIDIA platform evolution. The 800 VDC sidecar is the first solution on the way to 1 MW IT racks but it won’t be the only solution. We plan to continuously innovate power distribution and back-up solutions to drive increased resiliency, availability, and efficiency while simplifying deployment, operation and maintenance. To learn more about our commitment, read our press release.
Add a comment