Pushing the Boundaries of Transformers for Mass EV Charging

March 01, 2024 by Shannon Cuthrell

Smaller, power-dense magnetic transformer components enable mass charging for electric fleets in tight urban areas.

Electric vehicle (EV) fleets require high-power charging systems, which comes with the downside of relying on large, inefficient transformers and inductors. CorePower Magnetics, a Pennsylvania-based startup developing compact motors, inductors, and transformers, is partnering with Eaton to test lightweight, power-dense components capable of juicing up EVs quickly in space-constrained applications like urban fleets. 

CorePower’s advanced transformers are lighter and more efficient due to the high thermal stability of their magnetic cores, which can withstand temperatures of 250°C (or 482°F). The company envisions its products upgrading legacy distribution transformers with compact components for fast-charging systems, EV powertrains, and renewable energy integration. 


CorePower tests its transformer components under high temperatures.

CorePower tests its transformer components under high temperatures. Image used courtesy of CorePower Magnetics


National Renewable Energy Laboratory (NREL) is conducting a techno-economic analysis of the costs and benefits of CorePower’s technology. Since 2022, CorePower has been preparing and validating its components for demonstration as part of the Wells Fargo Innovation Incubator (IN2). With Eaton, it will test whether the technology is stable and capable of operating for several hours in real-world conditions. Its IN2 demonstration is expected to be complete in the next few years. 


CorePower’s transformer product.

CorePower’s transformer product. Image used courtesy of CorePower Magnetics


CorePower’s Compact and Power-Dense Technology

Magnetic power electronics components contain a core in the center wrapped in copper wiring to carry electricity. Transformers are designed to adjust current and voltage levels from one alternating current circuit to another. In electric grids, for example, step-down transformers reduce the input from high-voltage transmission lines to a lower output that can be directed to the end customer’s home or business. The benefits of using magnetics in these components include increased efficiency with fewer losses and high durability under extreme temperatures and mechanical stresses. 


Inside CorePower’s transformer.

Inside CorePower’s transformer. Image used courtesy of CorePower Magnetics 


CorePower, which spun out of Carnegie Mellon University in 2020, developed a novel class of metal amorphous iron-cobalt (FeCo) and iron-nickel (FeNi) nanocomposite alloys. These soft magnetic materials offer high permeability and density, corrosion resistance, and reduced eddy current losses—making them advantageous features in high-performance transformers. 

Today’s standard grid-connected transformers typically operate at 60 Hz. CorePower’s technology targets the frequency range of 10,000 Hz and above, meaning the size and weight of the transformer can be reduced while maintaining the same electrical performance. Its transformers have 100 kW of power and a 10 kHz frequency, while its 250 kW inductors range from 60 Hz up to 60 kHz. 

The company focuses on inexpensive ingredients that are easily magnetized and demagnetized. Using cobalt, iron, and nickel eliminates expensive rare earth metals dominated by foreign supply chains. 


CorePower’s inductor.

CorePower’s inductor. Image used courtesy of CorePower Magnetics


CorePower’s inductors enable high power density for EV charging and grid applications. Several years of engineering improvements have yielded a tenfold reduction in weight, a fivefold cut in volume, and half the energy losses. 


Manufacturing Magnetic Alloys

One critical selling point of CorePower’s technology is it allows more control and versatility in engineering the magnetic core components, which are optimized to eliminate localized hotspots accumulating excess heat. Changing how alloy compositions are heat-treated enables materials customized for transformers with high permeability or inductors demanding low permeability. In manufacturing, the amorphous metal ribbon is transformed into spatially tuned magnetic cores with the superior performance needed for EV charging. 

The company received $20 million from the U.S. Department of Energy (DOE) last November to construct a manufacturing facility for magnetic components and advanced metals in Pittsburgh. The factory will mass-produce amorphous and nanocrystalline alloys alongside component lines for motors and high-frequency transformers and inductors. The funding comes after the DOE’s Advanced Research Projects Agency-Energy awarded CorePower $5 million to establish a pilot processing line in 2022. 

Flush with federal funding and an earlier venture capital round led by Volta Energy Technologies in 2022, the company plans to ramp up its supply to 10,000 tons annually, targeting a 20% increase in its U.S.-based capacity. It hopes to snag 10% of the growing global demand for specialized magnetic metals.