Delta, a global provider of power and thermal management solutions, has commenced work on a research program, with 50% cost-share by the US Department of Energy (DOE), to develop a solid-state transformer (SST)-based extreme fast EV charger (XFC) with industry-leading capacity up to 400 kW to provide capable EVs a 180-mile range with less than 10 minutes of charging.

The proposed XFC design is expected to offer grid-to-vehicle efficiency up to 96.5%—four times less weight and half the size of conventional DC fast EV chargers (DCFC), as well as a high voltage direct current (HVDC) port to utilize energy storage and renewable energy systems, minimizing demand on the power grid.

This initiative will be supported and led by a program development team consisting of industry experts based out of Delta’s automotive division, located in the greater Detroit area (Livonia, MI), and researchers from the Delta Power Electronics Laboratory (DPEL), located in North Carolina’s Research Triangle Park.

Delta’s partners for this 3-year, US$7-million project include General Motors LLC, DTE Energy, CPES Virginia Tech, NextEnergy, the Michigan Agency for Energy’s Energy Office and the City of Detroit’s Office of Sustainability.

The novel SST power cell topology directly utilizes medium-voltage alternating current (MVAC) at 4.8-kV or 13.2-kV, eliminating conventional line frequency transformer (LFT) technology, which converts low voltage alternating current to a direct current (DC) to charge the high voltage battery in an EV.

Combined with a new silicon carbide (SiC) MOSFET device, the proposed SST enables a 3.5% improvement in grid-to-vehicle efficiency to industry-leading levels up to 96.5%, a 50% reduction in equipment footprint, and four times less weight than today’s DCFC EV chargers.

Moreover, the 400 kW XFC prototype, which is expected to be ready in 2020, will boast a power level enabling ground-breaking 3C charging speed on tomorrow’s long-range EVs. With this technology, EV drivers will need close to 10 minutes to achieve an additional 50 percent of vehicle range on their vehicle. For example, a 360-mile EV could achieve a 180-mile range in approximately 10 minutes of charging.

Early data and results from the program will arm automotive manufacturers, technology providers, cities and utilities with a greater understanding of how fast-charging will impact demand response efforts within specific circuits. The project will also provide insight into how renewable generation can be integrated to avoid infrastructure strain on the power grid associated with the wide deployment of XFCs.