*** 2/20/26 - Why investors are going gaga over solid-state transformers + 1/2/25 - The Solid-State Shift: Reinventing the Transformer for Modern Grids.........
Buzz Sawyer
Traditional transformers operate at low frequencies (50/60 Hz), requiring bulky cores and windings
(3) a related research paper is at link below:
https://techcrunch.com/2026/02/20/why-investors-are-going-gaga-over-solid-state-transformers/
Why investors are going gaga over solid-state transformers
It’s no secret that the electrical grid is aging, but one part stands out from the rest. Transformers haven’t changed much since Thomas Edison made his first light bulb.
Now, a string of startups are working to modernize the transformer, replacing it with modern power electronics that promise to give grid operators more control over how and where electricity flows.
“It becomes a very powerful device, equivalent to your internet router,” Subhashish Bhattacharya, co-founder and CTO of DG Matrix, told TechCrunch.
Three startups recently raised sizable rounds to scale up production of their solid-state transformer technologies. This week, DG Matrix raised a $60 million Series A and Heron Power raised $140 million in a Series B round. In November, Amperesand raised $80 million to chase after the burgeoning data center market.
Existing transformers are reliable and efficient, but that’s about it. They’re relatively crude instruments, made largely of copper and iron. They react passively to changes on the grid and are capable of tackling only one task per device.
“An old-school steel, copper, and oil transformer doesn’t have any monitoring, doesn’t have any control,” Drew Baglino, founder and CEO of Heron Power, told TechCrunch. In instances where electricity surges or a power plant trips offline, that can be a liability.
The devices can incorporate power from a range of difference sources — including traditional power plants, renewables, and batteries — and transform that electricity into either alternating current (AC) or direct current (DC) at a number of different voltages, allowing them to replace several devices.
For data centers, solid-state transformers offer an appealing alternative, allowing them to shrink the footprint of their power systems while giving them finer control over where and how electricity is directed.
Solid-state transformers are poised to arrive at a time when existing transformers are aging and demand for new ones is surging — a classic tech supercycle. Most transformers on the grid today are several decades old, according to the National Laboratory of the Rockies (NLR; formerly the National Renewable Energy Laboratory). As demand from data centers, EV chargers, and other parts of the grid rises, the NLR expects the amount of power flowing through transformers to double by 2050.
While data centers are the the first market those companies are chasing, they also have their sights set on the electrical grid, which in the U.S. alone hosts as many as 80 million transformers.
“All of the distribution transformers are ultimately going to need to be replaced. Over 50% of them are 35 years old. There’s a big need for an upgrade,” Baglino said.
Because they’re made from silicon-based materials, they’re flexible, controllable, and software-updatable. They’re also immune from price fluctuations that rock the copper market.
“Power semiconductors keep getting cheaper. Steel, copper, and oil, unfortunately, is not in that situation,” Baglino said. “Commodity prices can move all over the place, and they generally move up.”
In an old-style transformer, power flows into the transformer through copper wires wound around one side of an O-shaped iron core. As the electricity flows, it induces a magnetic field in the core. On the other side of the core, the magnetic field induces electricity in another set of copper windings. If the wires wrap around the core more times on the input side than the output side, the voltage decreases on the output side. If the ratio inverts, the output voltage increases.
Solid-state transformers eschew the copper windings in favor of semiconductors, using materials like silicon carbide or gallium nitride to handle frequency conversion. They can come in a range of configurations, with the most comprehensive setup consisting of three basic parts: a rectifier that converts alternating current to direct current, a converter that changes the voltage of the direct current, and an inverter that changes the direct current back into alternating current.
Unlike iron-core transformers, solid-state transformers can handle power that flows in both directions, making them useful in places that need backup power, like data centers.
In a data center, a solid-state transformer can replace several different pieces of equipment, not just the transformer that steps voltage down from the grid. Every data center uses backup power, which requires a string of devices to bring power into the facility. Solid-state transformers can handle all of those duties in one box.
The technology also allows data centers to more easily integrate so-called behind-the-meter power, where generating capacity is connected directly to the data center, not the grid. Those typically require another set of transformers.
And when coupled with grid-scale batteries, solid-state transformers can eliminate uninterruptible power supplies (UPS), too, freeing up space inside the data center for more racks.
“If you add up the cost of everything we’ve taken out, we’re 60% to 70% of that cost,” Haroon Inam, co-founder and CEO of DG Matrix, told TechCrunch.
DG Matrix has been focusing on its Interport technology, which can route power from multiple sources to multiple loads of differing voltages, a setup the company holds multiple patents on.
Heron Power, meanwhile, is working on transforming medium-voltage power in data centers, solar farms, and grid-scale battery installations. In a data center, its Heron Link transformers can provide racks with 30 seconds of power while backup sources come online. Altogether, Heron Link occupy 70% less space than existing parts. At a solar farm, Heron Power’s transformers can perform the duties of an inverter and a transformer for the same price.
In a head-to-head comparison, solid state transformers still command a cost premium over iron-core transformers. For that reason, they’re unlikely to replace the giant humming boxes at grid substations in the very near future.
But in data centers and at EV charging hubs, where solid-state transformers take the place of several pieces of equipment, they’ll start making inroads.
When they finally hit the grid in bigger numbers, they have the potential to cut down on transmission and distribution costs, one of the biggest contributors to utility bill inflation.
Because today’s transformers are passive, unable to react to fluctuations, distribution networks have been built with a significant amount of spare capacity, Baglino said. Solid-state transformers, though, can respond to changing conditions, allowing grid operators to send more power through the same lines.
“You can actually make the infrastructure more affordable because you’re putting more kilowatt-hours through the same poles and wires,” he said. “That’s where intelligence, in place of passive mechanical objects that were designed 100 years ago, can make a big difference.”
The Solid-State Shift: Reinventing the
Transformer for Modern Grids
Thursday, January 2, 2025
Transformers have been the backbone of power grids for over a century, but today’s demands for renewable energy, electric vehicles, and smarter grids are exposing their limits. Enter solid-state transformers—compact, efficient, and intelligent power solutions poised to revolutionize how electricity is distributed and managed.
The push to modernize the grid is exposing critical shortcomings of a century-old workhorse—the transformer. Stemming from Michael Faraday’s groundbreaking discovery of electromagnetic induction in 1831, the first transformer systems built circa 1885 revolutionized electricity transfer, essentially by enabling the step-up of voltage for efficient long-distance transmission and subsequent step-down for safe local use. The past century has characteristically introduced more significant innovations, including the transition from single-phase to three-phase systems for higher efficiency and reduced costs in long-distance power transmission. Modern developments include ultra-high voltage designs exceeding 800 kV and innovations in high-voltage direct current (DC) converter transformers for long-distance, low-loss energy transport. Today’s transformers are incorporating advancements such as wide-bandgap semiconductors for higher efficiency, modular designs for scalability, and eco-friendly insulation materials like synthetic esters to address environmental concerns.
However, despite recent innovations, conventional transformers remain ill-suited to meet the dynamic demands of modern grids. Although their fundamental design provides a cost-effective and reliable method to convert voltage and insulation levels, they are optimized for centralized, unidirectional power systems with simple structures. At the core of their limitations, as David Pascualy, a technical expert in solid-state transformers (SSTs) and power electronics, explained to POWER, “a normal standard transformer doesn’t communicate with the grid.”
Without advanced power electronics or sensors, conventional transformers cannot actively regulate voltage, mitigate harmonic distortion, or respond dynamically to grid disturbances, he said. Additionally, their lack of integration with digital control systems and grid communication protocols prevents them from supporting intelligent grid operations, such as voltage-ampere reactive (VAR) regulation, participation in grid demand response programs, predictive maintenance, or real-time optimization.
Traditional transformers operate at low frequencies (50/60 Hz), requiring bulky cores and windings that limit scalability, reduce efficiency, and make them impractical for space-constrained applications such as urban substations or offshore wind platforms, Pascualy noted. Their reliance on oil-based insulation and cooling also introduces environmental risks, demands significant maintenance, and leaves them vulnerable to failures under extreme weather conditions or fluctuating loads.
SSTs: A New Breed of Transformers
To address these limitations, research into solid-state transformers (SSTs) has been ongoing since the 1960s. William McMurray, an engineer at General Electric, first proposed the concept of an “electronic transformer” in 1968 in a design that introduced high-frequency alternating current-to-alternating current (AC/AC) converters. The design allowed for voltage transformation using power electronic components, marking a foray away from traditional low-frequency transformers and demonstrating how high-frequency operation could enable more compact and efficient designs. The concept was later refined by contributions such as J. L. Brooks’ SST in 1980, and the Electric Power Research Institute’s (EPRI’s) introduction of the Intelligent Universal Transformer (IUT) in 1995. The IUT incorporated features such as bidirectional power flow, voltage regulation, and seamless AC/DC conversion.
In This Issue
January 2, 2025Full issueAccording to Pascualy, recent advancements in materials and design continue to significantly enhance the performance and applicability of SSTs. Wide-bandgap semiconductors, such as silicon carbide (SiC) and gallium nitride (GaN), today enable higher switching frequencies, reduced energy losses, and improved thermal management. High-frequency transformers (HFTs), constructed with advanced magnetic materials like ferrites or amorphous alloys, further contribute to size and weight reductions while maintaining high power density and minimal energy loss. In addition, modular topologies, such as multilevel converters and dual active bridges, enhance operational flexibility, allowing SSTs to handle diverse voltage levels and operational conditions effectively. Coupled with advanced cooling technologies and intelligent control algorithms, these innovations are making them robust for modern grid applications, he said.
What Is a Solid-State Transformer?Unlike conventional transformers that rely on heavy iron cores and low-frequency operation, solid-state transformers (SSTs) use a multi-stage architecture and high-frequency transformers (HFTs) to achieve significant improvements in size, efficiency, and functionality. Essentially, SST functionality relates on three core stages (Figure 1).
 1. Overview of the solid-state transformer (SST) infrastructure, showcasing modular design, high-frequency transformers, and advanced power electronics for compact, efficient, and bidirectional power flow. Note: AC = alternating current; DC = direct current; HV = high voltage; and LV = low voltage. Source: Agarwala et al., 2024.Compared to conventional transformers, SST designs notably include advanced features, including modular configurations, such as multilevel converters and dual-active bridges, which enhance scalability and operational flexibility. At the same time, integrated sensors and intelligent control algorithms can enable real-time monitoring, voltage regulation, harmonic filtering, and fault isolation. SSTs also support grid communication protocols, ensuring seamless integration with renewable energy systems and DERs. Notably, however, the functionality and applicability of SSTs depends significantly on their configuration, which determines their performance in various scenarios. One-Stage Configuration. The design involves direct AC-to-AC conversion without a DC link. While cost-effective, lightweight, and suitable for basic voltage transformation, it lacks the advanced capabilities needed for reactive power compensation and renewable energy integration. The configuration may be ideal for applications in rural and industrial settings where simple step-down voltage conversion is necessary. Two-Stage Configuration. Incorporates a DC link on either the primary or secondary side on either the high-voltage (primary) or low-voltage (secondary) side of the transformer, enabling more advanced functions. These include, for example, reactive power compensation, improved voltage regulation, and integration with DERs and energy storage. The configuration is better suited for electric vehicle (EV) fast-charging stations, where DC conversion is critical, and for renewable energy microgrids that need reliable voltage regulation and storage integration. Three-Stage Configuration. Features dual DC links on both the high- and low-voltage sides. While complex and costly, this configuration provides the highest level of operational flexibility, bidirectional power flow, robust reactive power management, and seamless DER connection. Applications generally envisioned include urban substations, offshore wind platforms, and data centers, which generally need compact, efficient, and highly controllable power management. |
Pilot Projects and Promising Applications
As Pascualy pointed out, interest in SSTs has been growing as the urgency to outfit grids with more capable, intelligent, and dynamic solutions mounts. But while SSTs are promising, they largely remain in the research and development phase. SST “pilot projects and pre-commercialization studies are just now emerging” he noted. “Some of the big powerhouses are developing SSTs for certain aspects of their designs.”
So far, a handful of pilot projects and commercial offerings demonstrating their potential are underway, mostly focused on electric vehicle (EV) charging and solar and wind energy integration. Singapore-based startup Amperesand—a company founded by industry veterans from ABB, General Electric, Siemens and Vestas—is poised to begin a one-year proof-of-value trial in mid-2025 to demonstrate the capabilities of its SST technology at Singapore’s port. The trial, conducted in collaboration with venture capital firm PSA unboXed, will evaluate Amperesand’s modular, SiC-based SST systems in providing efficient, compact, and bi-directional charging solutions for PSA’s electric prime mover fleet. “The modular and scalable design enables PSA to manage its electric vehicle charging facilities with greater flexibility, distributing power economically across the facility’s high-capacity dispensers,” the company said in October.
Taiwanese power electronics manufacturer Delta, meanwhile, in October 2022 demonstrated a 400-kW extremely fast EV charger that utilizes SiC MOSFET-based SST technology that operates directly from a 13.8 kVA medium-voltage input. The innovation, bolstered with a grant from the U.S. Department of Energy, was developed in collaboration with partners like General Motors and Virginia Tech. It eliminates traditional transformers, improves efficiency to 96.5%, and integrates seamlessly with renewable energy and storage systems, Delta says. Pascualy is chief commercial officer CCO at Alderbuck Energy Inc., an advanced power electronics company, developing multi-stage SST technology prototypes with industry partners. EPRI in 2023 evaluated a novel SST design that could replace existing 25-kVA distribution transformers while also having voltage regulation capabilities.
Most R&D for SSTs appears largely centered on medium-voltage to low-voltage transformations, typically from a range of 13.2 kV to 15 kV down to lower voltages for various end-use applications (Figure 2), Pascualy noted. The near-term focus is “going to really be at the distribution level,” even though SST harbors a potential expansion into higher-voltage transmission, he suggested. Data centers represent another key sector looking intently at SSTs, given their potential to serve as a more efficient and integrated interface between an AC grid and a DC-powered data center, he said.
2. Solid-state transformers (SSTs) can enable efficient bidirectional power flow, renewable energy integration, and enhanced voltage regulation in modern distribution networks. Note: MV = medium voltage. Source: Shadfar et al., 2021, International Transactions on Electrical Energy SystemsSeveral Barriers to Overcome
While progress is encouraging, several barriers must be overcome before the technology can achieve mainstream adoption in the power industry, said Pascualy. A key challenge is cost. SSTs are more expensive than conventional transformers owing to their advanced materials, complex designs, and reliance on semiconductor-based power electronics, however they bring high value due to the additional capabilities they provide, which are not possible in standard transformers.
As with all novel power technology, achieving economies of scale and driving down manufacturing costs will be essential for making SSTs a viable option for utilities and grid operators. Reliability and field performance are also critical factors, and SSTs, with their multi-stage designs and advanced control capabilities, will need to undergo extensive testing and validation to ensure they can withstand the rigors of real-world grid operations. “You can’t possibly figure out everything that’s going to happen in the field. And you have different use cases that can produce different kind of results,” Pascualy said. “So, I think that that that is just a matter of maturing.”
The first crucial step could arrive with more widespread deployment of hybrid SSTs, which integrate the functionalities of traditional transformers and advanced SSTs to achieve modular and efficient designs. Hybrids, envisioned to feature multiple stages of voltage conversion, such as AC-DC and DC-AC, and can include both high-voltage and low-voltage DC links, are largely unavailable commercially. The University of Texas at Austin, supported by a DOE grant under the Transformer Resilience and Advanced Components (TRAC) program, has so far developed and demonstrated a 500 kVA Hybrid Solid-State Transformer (HSST) that combines dual active bridge-based SST technology with a conventional dry-type transformer. The project explored advanced capabilities such as voltage regulation, fault detection, and dynamic state estimation for modern grid applications. More research is ongoing at North Carolina State University’s FREEDM Systems Center focusing on innovations such as solid-state transformers to enhance renewable energy integration and grid efficiency.
While challenges remain in fully commercializing SST technology, Pascualy is optimistic about its potential to revolutionize grid modernization. “The grid is receiving a lot of attention right now, but we’re adding so much more to it,” he said. Collaborative efforts between technology companies, utilities, and research institutions will be crucial in driving the widespread adoption of SSTs, he predicted.