Solid-state transformer

A solid-state transformer (SST), power electronic transformer (PET), or electronic power transformer is an AC-to-AC converter, a type of electric power converter that replaces a conventional transformer used in AC electric power distribution. It is more complex than a conventional transformer operating at utility frequency, but can be smaller and more efficient than conventional transformers because it operates at higher frequencies. Solid-state transformers are an emerging technology as of 2025.

Solid-state transformers can actively regulate voltage and current. Some can convert single-phase power to three-phase power and vice versa. Variations can input or output DC power to reduce the number of conversions, for greater end-to-end efficiency. As a complex electronic circuit, it must be designed to withstand lightning and other surges.

The main types are true AC-to-AC converter (with no DC stages) and AC-to-DC-to-DC-to-AC converter (in which an active rectifier supplies power to a DC-to-DC converter, which supplies power to a power inverter). A solid-state transformer usually contains a transformer, inside the AC-to-AC converter or DC-to-DC converter, which provides electrical isolation and carries the full power. This transformer is smaller due to smaller DC-DC inverting stages between transformer coils, which consequently mean smaller transformer coils required to step up or step down voltages.

A modular solid-state transformer consists of several high-frequency transformers and is similar to a multi-level converter.

Commercial development

Investor interest in solid-state transformers accelerated in 2026, driven by two converging demand pressures. Nvidia's August 2026 disclosure of an 800V DC AI factory architecture created upstream demand for medium-voltage to 800V DC conversion at data centre perimeters, while conventional medium-voltage transformer supply was simultaneously constrained by multi-year OEM lead times.

DG Matrix, a solid-state transformer company founded in 2022 and headquartered in Raleigh, North Carolina, closed a $60 million Series A round in February 2026 led by Engine Ventures with participation from ABB and Mitsubishi Heavy Industries. On June 17, 2026, DG Matrix announced that its Interport multi-port solid-state transformer had joined the Nvidia MGX ecosystem as a supplier for Nvidia's 800V DC AI factory architecture.

Heron Power, founded in 2024 and based in the San Francisco Bay Area, raised a $140 million Series B on February 18, 2026, co-led by Andreessen Horowitz's American Dynamism Fund and Breakthrough Energy Ventures. On August 13, 2026, Heron selected Morgan Hill, California as its first large-scale factory site, designed to produce up to 10,000 units annually, with production targeted for the second half of 2027.

Amperesand, dual-headquartered in San Francisco and Singapore, raised approximately $92 million across two primary rounds, including an $80 million round in November 2025 led by Temasek.

Further reading

• Kumar, Adi. "The Wide-Bandgap Stack: Boom, Bust, and the Rebuild of AI's Power Semiconductor Chain", adikumar.co, August 2026. Industry analysis of the wide-bandgap semiconductor supply chain that underpins the SST commercial ramp.
• Kumar, Adi. "DG Matrix: Underwriting the Multi-Port SST Bet at the AI Factory Perimeter", adikumar.co, August 2026. Independent underwriting treatment of the multi-port SST commercial thesis.

References

• "Are Solid-State Transformers Ready for Prime Time?". 3 August 2017.
• "Solid State Transformer For Power Distribution Applications" (PDF).