SAE standard to connect electric cars to the Smart Grid

Auto makers hope to ratify in January the first draft of a standard that will link electric vehicles to the smart grid. Over the next year, the group aims to define a suite of five standards including ones describing ways to link electric cars to home networks.

“All the car makers are in our group and similar efforts at the ISO and IEC,” said Rich Scholer, chairman of the J2293 task force at the Society of Automotive Engineers (SAE) that is developing the standards.

“People are building electric vehicles and their supply equipment right now so these things need to get sorted out,” said Scholer who is also a design engineer for plug-in and fuel cell vehicles at Ford Motor Co.

Engineers are debating whether the vehicles or their third-party electronic gear should handle smart grid transactions. “The path we are heading down is there is no one right answer,” said Jose Salazar, a technical specialist at Southern California Edison who works with the SAE and other standards groups.

The SAE group formally started its work in February 2008 and now has as many as 160 members. It will conduct simulation testing and modeling of products based on its specifications when they are completed and then revise the standards based on what they learn from the tests.

As a first step, the group expects to have an initial vote in January on a standard that will define the physical and media access control layers for a network linking electric cars and the smart grid. It will also define use cases and messaging protocols for the network. The link would allow a car to get data about the costs of charging at different times given traffic on the grid.

The spec is based in part on the Smart Energy Profile (SEP) 2.0 being developed by a collaboration between the Zigbee Alliance and the HomePlug Alliance.

The efforts are very much a work-in-progress.

“SEP 2.0 has an initial technical requirements document that will be published in a month or two,” said Scholer. “We have our initial SAE documents that will reflect some of this plus a lot more info for vehicles and supply equipment,” he said.

The SAE has laid out plans for four other specs beyond the baseline utility standard it hopes to ratify in January. The SAE has laid out plans for four other specs beyond the baseline utility standard it hopes to ratify in January.

By mid 2010, the SAE aims to define standards for DC energy transfer and reverse energy flow systems from a car battery to a home or to the grid. It also aims to specify a set of diagnostics for its powerline technology so it can, for example, provide car owners a gauge of how fast their car is charging.

By the end of the year, the group also hopes to define a set of protocols for linking the electric cars powerline connection to a home network. Such links would let a car synch up its digital music and video content with a home PC or server while it is charging.

Courtesy: EETimes.

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