US Navy Solid-State Transformer-Rectifier Programs Are Building MVDC

The United States Navy has developed solid-state transformer-rectifier (SSTR) hardware specifically for shipboard medium-voltage DC (MVDC) power distribution on all-electric surface combatants. The Navy SSTR converts 13.8 kilovolts AC ship-service input to plus/minus 850 volts DC at the rectifier output, with the modular line-replaceable units (LRUs) designed for “hatchable” replacement — the LRU must be small enough and light enough to be removed and replaced through the standard ship hatchway by a damage-control party at sea.

The Navy’s commitment to MVDC shipboard power is documented in IEEE Standard 1709-2018, which defines MVDC voltage classes from 1 kilovolt to 35 kilovolts and is the reference standard for both Navy and commercial shipboard MVDC system design. The Navy’s engineering case for MVDC over conventional 4160-volt AC shipboard distribution is straightforward: pulsed-DC loads from directed-energy weapons (high-energy lasers, railguns) and from the electromagnetic catapult on the Ford-class aircraft carriers are nearly impossible to manage cleanly on a shared AC distribution bus, but route directly to a DC bus.

The SSTR application is the medium-voltage-to-low-voltage interface between the ship’s 13.8 kilovolts AC primary distribution and the lower-voltage DC sub-buses that feed individual mission systems, fire-control radars, and propulsion auxiliaries. A single SSTR can replace approximately three to five separate conventional pieces of equipment: a step-down distribution transformer, a thyristor rectifier, a harmonic filter, a power-factor-correction cabinet, and downstream isolation. The reduction in shipboard footprint and weight is operationally significant on a hull where every cubic meter and every kilogram displaces fuel, ammunition, or aviation assets.

The Navy SSTR program has been managed primarily through Office of Naval Research SBIR and STTR Phase I, II, and III contracts, with parallel Defense Advanced Research Projects Agency (DARPA) interest. The specific SST architecture used in the Navy program incorporates silicon carbide (SiC) MOSFETs that are the same device family commercial MV-SST suppliers use, although qualification to military environmental specifications (MIL-STD-810, MIL-STD-461 for electromagnetic compatibility) requires substantial additional engineering work compared to commercial product certification.

The Navy’s investment in shipboard MVDC and SSTRs is also feeding the commercial SST industry indirectly. The wide-bandgap semiconductor research effort funded under Defense Production Act Title III, the ARPA-E CIRCUITS program, and parallel ONR programs has substantially compressed the maturation timeline for the SiC devices that today’s commercial MV-SST products use. The commercial SST industry that emerged in 2024 and 2025 is, in part, a beneficiary of two decades of US Navy MVDC research investment.

Critical Perspective

Editorial correction: This post is part of MGRID’s Solid-State Transformer industry coverage. As of May 2026, that body of work systematically framed manufacturer announcements, funding rounds, and laboratory demonstrations as commercial deployments. The reality is that field-deployed commercial-class SST in revenue service globally is measured in single digits, and almost every product cited in this series is at “announced” or “funded” stage, not “operational.” Readers should treat the specific claims in this post against the standards documented in our SST Industry Reality Check (the per-claim audit table maps marketing language to verifiable deployment status). The corrective article is the canonical reference for SST industry reality; this post remains published with its original framing so the editorial drift is traceable.

Related Coverage

• ARPA-E Modular Solid-State Transformer Program Awards Georgia Tech: ARPA-E program awards for modular solid-state transformers
• The Federal R&D Investment Ecosystem Under the US Solid-State Transformer Industry: ARPA-E, DOE OE, NSF FREEDM, and Why It Matters: Federal R&D investment in US solid-state transformer industry
• Deepak Divan: The Georgia Tech Professor Whose Three-Decade Research Program Seeded Resilient Power Systems and Eaton’s Solid-State Transformer Business: Georgia Tech professor’s research seeded resilient power systems
• NoMIS Power Joins ARPA-E DC-GRIDS Project: ARPA-E DC-GRIDS project involves solid-state transformers