Siemens and Reinhausen are jointly developing a solid-state transformer for AI data centers. The system connects to grid voltages up to 36 kV and delivers 800 V DC directly. Both companies aim not only to develop the technology but also to industrialize it for mass production.
The two German companies announced a strategic partnership to bring to market a solid-state transformer (SST) suitable for medium voltage up to 36 kV. The goal is to power data centers running AI workloads with an architecture that has fewer conversion steps.
In such a setup, medium-voltage AC is converted directly to 800V DC and distributed from there. This eliminates intermediate AC/DC conversion stages compared to traditional, multi-stage power supply architectures. Galvanic isolation remains intact.
The design is modular and can also be applied at lower voltages, depending on the grid connection. The output is a stable 800V DC rail voltage, intended for direct connection to downstream DC distribution or loads.
Who brings what to the table
Reinhausen provides voltage regulation technology for power transformers and has expertise in medium-voltage power electronics, the foundation of modern SST architectures. Siemens contributes power electronics, grid protection, automation, and digitalization.
“Solid-state transformers are critical for these large and power intensive structures. They enable higher efficiency, direct grid-to-rack DC conversion, and a reduced footprint,” said Stephan May, CEO of Electrification and Automation at Siemens. According to him, the systems respond to load changes within milliseconds, allowing them to handle the peaks of AI training workloads.
Reinhausen has indicated that series production will eventually follow. Neither party has provided a specific timeline for availability at this time.
Tip: Research on 800V DC: risks comparable to conventional AC