Feb
12
The Latest Electric Vehicle Controller
February 12, 2010 | 2 Comments
The researchers at the Department of Energy’s Oak Ridge National Laboratory have designed, fabricated and demonstrated a PHEV traction drive power electronics system that provides significant mobile power generation and vehicle-to-grid support capabilities. (The Oak Ridge press release isn’t specific, but here PHEV seems to mean Plugin Hybrid Electric Vehicle, not parallel hybrid EV.) The device acts as the vehicle charger.
Oak Ridge PHEV Controller. Click image for the largest view. A high resolution image is on the Oak Ridge press release page.
The effort has yielded an interesting take on the potential that an EV controller offers when there is substantial storage and some generation ability. Have a seat – this hasn’t occurred to many – the Oak Ridge controller provides more power than typical freestanding portable generators; the PHEV can be used in emergency situations such as power outages and roadside breakdowns or leisure occasions such as camping. Day-to-day, the PHEV can be used to power homes or businesses or supply power to the grid when the power load is high.
In the midst of freezing rain, ice storms and “snowmageddon” the press release seems prescient or well planned, perhaps. But the idea positioning has serious emergency value merits. It would not be much of an expense to wire one’s home charge arrangement such that emergency power would be available from the car.
Oak Ridge likes to say it as “An advancement in hybrid electric vehicle technology is providing powerful benefits beyond transportation.” That’s a little strong, but lets look at what information is available.
Gui-Jia Su of ORNL’s Power Electronics and Electric Machinery Research Center says, “The new technology eliminates the separate charging mechanism typically used in PHEVs, reducing both cost and volume under the hood. The PHEV’s traction drive system is used to charge the battery, power the vehicle and enable its mobile energy source capabilities.” Wait a minute . . . That remark would mean to this writer that wall current would be the connection to the EV, not a charger. Not a special plug. If so, that does simplify things, one would need either a 110 volt or 220 volt extension cord for the personal infrastructure investment for EV ownership.
Su also offers the charging system concept, which is market ready, could also be used to enhance the voltage stability of the grid by providing reactive power. Some clever folks out there with smart meters are thinking they might hedge the power company; take current overnight, give back current during the afternoon. Whether the pricing will make that viable isn’t a topic yet – it had better be soon.
The controller is the work of The Power Electronics and Electric Machinery Research Center, the DOE’s broad-based research center, charged and funded for helping lead the nation’s advancing shift from petroleum-powered to hybrid-electric and plug-in hybrid vehicles. The center’s efforts directly support DOE’s Vehicle Technologies Program and its goal to provide Americans with greater freedom of mobility and energy security while lowering costs and reducing impacts on the environment.
From the photo above some interesting features are visible. The controller is built on a production DSP universal controller board. It’s using a Texas Instruments chip. And it’s cooled with a fluid system seen to the right side. It’s not especially big either. As a lab unit it’s not been optimized for production, but the row of 10mm Phillips headed cap screws denote the diminutive size.
By no means is this all there is to controlling the power in an EV though. The controller Oak Ridge is proposing is more of an interface controlling device between the battery or capacitor pack and line in or grid source. There seems to be no facility to control the vehicle itself. Which is just as well. That is an area if intense engineering interest to auto manufacturers worldwide.
That suggests the Oak Ridge controller would be an option in an EV design. Should the offering actually simplify the charging at home and reduce the infrastructure cost for someone to switch over, the market should be very welcoming indeed. But that’s not to say that every EV would have one, or that every buyer would understand why or why not they’d want one.
Building the technology is one thing. Teaching consumers how it is their interest might be much harder. But I’d be game; power went down a couple days here, having the furnace run would nave been really nice.
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Is this a liquid cooled controller? Are EV’s mostly liquid cooled? I have no experience with them.
This sort of design makes total sense. Regenerative braking is a standard feature on modern electric vehicles. To do regenerative braking, the vehicle motor becomes a generator. The energy from the braking is used to charge the vehicle battery. For regular recharging, the only difference is that the braking is being done on the generators connected to the power grid.