4 September 2018

Delta begins US DOE-sponsored program to develop microgrid-capable solid-state transformer-based 400kW extreme fast chargers for electric vehicles

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Power and thermal management solutions provider Delta has begun work on a three-year, $7m 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 400kW to provide capable EVs with 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%, 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 are intended to accelerate the ubiquitous adoption of EV charging.

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

“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,” says M.S. Huang, president of Delta Electronics (Americas).

The novel SST power cell topology directly utilizes medium-voltage alternating current (MVAC) at 4.8kV or 13.2kV, 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 up to 96.5%, a 50% reduction in equipment footprint, and four times less weight than existing DCFC EV chargers. Moreover, the 400kW XFC prototype, which is expected to be ready in 2020, will have 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% of vehicle range on their vehicle. For example, a 360-mile EV could achieve a 180-mile range in about 10 minutes of charging.

Early data and results from the program should give automotive manufacturers, technology providers, cities and utilities a greater understanding of how fast charging can 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.

Tags: SiC MOSFET

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