Delta has commenced work on a trend-setting research program, with 50 percent cost-share by the U.S. Department of Energy (DOE), to develop a solid-state transformer (SST)-based extreme fast EV charger (XFC) with industry-leading capacity up to 400kW to provide capable EVs a 180-mile range with less than 10 minutes of charging.
Moreover, the proposed XFC design is expected to offer grid-to-vehicle efficiency up to 96.5 percent, 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. All these unique features will accelerate the ubiquitous adoption of EV charging and are expected to enhance Delta’s leadership within the e-mobility sector.
This market transformation 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 ground-breaking 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.
“We’re thrilled to lead such an important project and have a stellar team of researchers and partners in place that are more than ready to take on the challenge of setting a new standard for EV fast charging,” said M.S. Huang, president of Delta Electronics (Americas). “By utilizing solid-state transformer technology, we have the opportunity to create unprecedented charging speed and convenience that will ultimately help support the DOE’s strategic goal of increasing EV adoption across the nation.”
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 ac to 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 percent improvement in grid-to-vehicle efficiency to industry-leading levels up to 96.5 percent, a 50 percent reduction in equipment footprint, and four times less weight than today’s DCFC EV chargers.
Moreover, the 400kW 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.