The Genovation Cars G2 concept plug-in electric hybrid vehicle model during aerodynamics testing at the Glenn L. Martin Wind Tunnel at University of Maryland in College Park, Maryland, January 26, 2012.
The Electric Power Research Institute (EPRI) describes its new technology as a 2.4 kilovolt, 45kVA (45,000 volt amps for the less technical among us) solid-state, direct current (DC) fast charging system for electric vehicles (EVs).
What sets EPRI’s new system apart is that the Utility Direct Fast Charger will not only provide fast charging of plug-in EVs, but also give utilities the option of providing fast charging directly from their distribution systems. As EPRI notes, that feature could make it particularly useful in heavily-populated cities: fast charging systems could be placed in areas where there are no chargers made available by businesses.
Also, businesses could install the system’s Universal Transformer Technology (IUT) as their building transformer, which would make it easier to add fast charging service and to integrate onsite solar power storage and building energy management systems. The multitasking setup also could help control peak loads from the DC charger – and their impact on utilities and costs of service to businesses (by reducing demand charges).
A third possible application is that the DC fast charging technology could potentially increase the range and flexibility of plug-in EV which EPRI says could give them more commercial appeal.
Electric vehicle adoption faces a range of challenges, many of which were outlined in an October industry report that can be found on Breaking Energy here.
What’s under the hood, as they say?
The Utility Direct Fast Charger has fewer parts than those being designed and used now. Because of the relatively simple design, it is expected to be cheaper to install and be significantly more efficient than today’s fast charging systems. EPRI says the efficiency of conventional charging system tops out 90-92%, and that efficiency drops a bit when hooked up with the needed three-phase power supply transformer.
In contrast, EPRI’s technology is expected to hit overall system efficiency of 96-97%. The IUT technology mentioned earlier “replaces both the independent power conversion units as well as the conventional transformer with a single interface system which can be used for fast charging of electric vehicles,” according to an EPRI overview.
Getting rid of the conventional transformer also makes the IUT-DC fast charger a lot lighter than its traditional counterparts. As EPRI puts it, “The standard ANSI based 50-kW transformer weighs more than 800 pounds. The entire charging station including the low-voltage based charger will weigh more than 1,000 lbs. On the other hand, the weight of the entire EPRI IUT-DC fast charger electronics is less than 150 lbs.”
EPRI will demonstrate the technology at its Knoxville, TN-based laboratory to confirm the system’s ability to provide a full EV charge. The demonstration will be the first of several with the goal of taking the technology from prototype to field demonstrations.