Who makes SSTs (emerging) for AI data centers

A conventional transformer changes voltage with magnetics and nothing else. A solid-state transformer does it with power electronics around a much smaller high-frequency magnetic core, which makes it far more compact for the same rating and, more importantly, controllable — it can regulate voltage, manage power flow in both directions, isolate faults quickly, and present a DC port directly. That DC port is why this part sits under the 800 V DC architecture rather than beside conventional transformers. Rack power has risen to the point where distributing at higher DC voltage inside the row removes conversion stages and copper, and a device that can take medium-voltage AC and hand back regulated DC collapses several pieces of the traditional chain into one. It is the enabling component for that architecture rather than an efficiency improvement to the existing one. The reason the catalog marks it emerging is that the trade is real. Solid-state transformers are more complex, contain semiconductors and capacitors that age, and have far less field history than a magnetic transformer that will outlast the building. Reliability at data center scale is not yet demonstrated the way it is for the incumbent. What to look for is whether a product exists in the voltage and power class a site needs or only in adjacent markets such as traction and charging, and what the failure and service model looks like compared with a passive transformer.