For decades, electrical engineers have dreamed of a device that can seamlessly connect solar panels, battery systems, and on-site generators to high-powered equipment like EV chargers or data center servers, without loads of expensive hardware to make it all work together.
Now, these devices, called solid-state transformers, are actually starting to hit the market — and they couldn’t be coming at a more opportune time.
Right now, these large electricity customers are clamoring for more power than the U.S. grid can easily supply. In theory, this problem could be solved by allowing them to install their own solar arrays, batteries, and generators on site — ideally as a microgrid — but that seemingly simple solution is actually complicated and costly to execute.
Every solar array, battery, fuel cell, generator, or other source of on-site power requires multiple pieces of equipment — electrical protection gear, isolation transformers, step-up and step-down transformers, power converters — to safely turn direct current into alternating current or vice versa, and to raise or lower voltages to match the needs of different loads within a building.
Solid-state transformers can do all that from a single device, controlling electricity as nimbly as routers control the flow of data. That’s particularly valuable when it comes to managing equipment with high power needs, like EV chargers, or with extremely sensitive requirements for power quality, like the server racks populating data centers.
So says Haroon Inam, CEO and cofounder of DG Matrix, one of a handful of companies starting to get solid-state transformers into real-world applications. DG Matrix raised $20 million in March and is building a factory in North Carolina, set to open late this year, that will be capable of producing up to 1,000 units annually, he said.
“We’re hitting the massive underserved commercial and industrial microgrid market,” he said. “People haven’t done it because it costs so damn much to build individual snowflake microgrids.”
“People have been working at this technology for well over a decade,” said Aidan Graham, senior vice president and general manager of Eaton’s critical power solutions business. But now, following several key engineering advances, the technology may finally be ready for primetime — and utilities and others are starting to test it out.
The evolution of solid-state transformers
Eaton has been working on solid-state transformers for years. The company isn’t saying how it intends to scale up manufacturing and deployment of Resilient Power’s technology. But “there are a couple of branches we’re chasing,” Graham said, including EV charging and integrating batteries into data centers and other critical environments, “where people‘s lives are on the line, or a lot of money is on the line, if the power goes out for even a fraction of a second.”
Michael Wood III, DG Matrix’s chief of staff, said the company is testing its devices with companies including electrical-equipment manufacturing giant ABB, North Carolina-based utility Duke Energy, and PowerSecure, a major microgrid and data-center power system developer owned by utility Southern Co.
“The best way to get the next gigawatt of energy is to build distributed systems,” Wood said. “Today, you need all of this gear to make those projects work. DG Matrix eliminates all that balance of systems and boils it down to a single system.”
Using a DG Matrix solid-state transformer can cost half as much as using the standard mix of multiple technologies to connect the components of a typical on-site microgrid, Inam said. It also makes it a lot simpler to quickly mix and match devices or to change up the configuration of systems at data centers, EV charging hubs, and other potential microgrid sites.
So if solid-state transformers are such a useful technology, why are they just now getting into the field?
There are good reasons why it’s taken so long, said Vlatko Vlatkovic, a veteran of General Electric’s industrial electrification business and a partner at DG Matrix investor Clean Energy Ventures, who joined the startup’s board of directors this year.
Much of the power grid relies on electromechanical devices that operate in relatively simple ways that haven’t changed much in a century. Despite recent advances that have enabled things like solar inverters or electric-vehicle drivetrains, the same kind of semiconductors that make modern computing possible have yet to be applied widely to the power grid.
