With power demand surging as AI data centres expand, solid-state transformers, which are smaller than conventional transformers and have better power control functions, are drawing attention as an alternative to ease power grid bottlenecks.

On Oct. 27, IT outlet MIT Technology Review reported that in the United States, supplies of large transformers are failing to keep pace with demand, pushing delivery times for some equipment to as long as 5 years. Conventional equipment is large and heavy because it uses specialised steel plates and large amounts of copper wire, and production also requires skilled workers.

Solid-state transformers control current frequency and voltage using power semiconductors. They convert alternating current to direct current, then use silicon carbide semiconductors to create high-frequency alternating current and change the voltage. Some designs can deliver the same capacity in about one-tenth the size of conventional equipment. They can also integrate rectifier and inverter functions to reduce facility space and power losses.

Verification in real grid conditions has also been carried out. A research team at North Carolina State University developed a 1-megawatt prototype with the New York Power Authority and the Electric Power Research Institute (EPRI). It was operated after being connected in June to a 13,200-volt distribution line at a test facility in Massachusetts, and results were released in August.

The research team measured a peak efficiency of about 98 percent for the power conversion module in the laboratory. That is higher than about 96 percent for a combination of a conventional transformer and rectifier, but it has not been proven that the overall device efficiency was 98 percent in the field test.

Private investment is also rising. In February, Heron Power raised $140 million, or about 186.98 billion won, and is pushing to commercialise its solid-state transformer, Heron Link. It plans to apply it to data centres, solar power generation and energy storage systems. In California, it is also preparing tests linked to a 10-megawatt-hour battery.

Still, additional development is needed to replace even high-voltage transmission grids. Long-term operating reliability, fault response and standardisation also remain challenges, and for now there is talk of possible applications in medium-voltage facilities such as data centres.