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Rolls Royce demos wireless charging for EVs

European company offers induction charging system for electric vehicles.


March 2, 2011
by Canadian Automotive Review staff

LONDON, UK: Rolls Royce Motor Cars will use induction charging technology for a version of its 102EX Phantom Experimental Electric vehicle revealed at the Geneva auto show on March 1, 2011. Rolls Royce says it has no plans to build a production version of this car. Phantom EE’s role is as a test bed, designed to explore technologies and pose as well as answer questions.

HaloIPT is the first company in the world to bring to market wireless charging technology, which allows cars fitted with an integrated receiver to charge automatically when parked over transmitter pads buried in the ground. HaloIPT’s wireless charging systems use inductive power transfer (IPT) to transfer power over large gaps and are tolerant to parking misalignment with power transfer efficiencies that can match a plug-and-cable. The technology is designed to function beneath asphalt, and even works under water or covered in ice and snow. IPT systems can be configured to work with all road-based vehicles from small city cars to heavy-goods vehicles and buses.

Rolls-Royce Motor Cars has developed the test vehicle to explore alternatives to traditional internal combustion for the first time in the company’s 107 year history. HaloIPT is part of an exclusive group of innovators whose systems have been integrated into the experimental vehicle.

In future, infrastructure providers will be able to embed IPT technology into roads, so HaloIPT cars can be charged on the move. This dynamic in-motion charging represents the most effective way of solving the range issues faced by electric vehicles today and will significantly reduce battery size requirements as well as providing unparalleled charging convenience.

“We are delighted to provide our wireless charging technology for this trial. Industry feedback so far tells us that the automation advantages of wireless charging make it the best charging solution for luxury electric vehicles and will be the key to unlocking the potential of this exciting market,” says Anthony Thomson, CEO of HaloIPT. “Users don’t need to get out of their vehicles and hunt for a cable to plug-in, they will just park and walk away while their car starts charging automatically…the ultimate in modern convenience.”

Concerns about lack of available re-charging infrastructure in towns and cities are well documented and critics of electric motoring point to the additional inconvenience of trailing cables connected between power source and vehicles.

There are two main elements to induction charging; a transfer pad on the ground that delivers power from a mains source and an induction pad mounted under the car, beneath Phantom EE’s battery pack. Power frequencies are magnetically coupled across these power transfer pads.

The system is around 90 percent efficient when measured from supply to battery. Also, it is not essential to align the transmitter and Phantom receiver pads exactly for charging to take place. While pads are capable of transmitting power over gaps of up to 400mm, for Phantom EE the separation is in the region of 150mm.

The coupling circuits are tuned through the addi­tion of compensation capacitors. Pick-up coils in the receiver pad are magnetically coupled to the primary coil. Power transfer is achieved by tuning the pick-up coil to the operating frequency of the primary coil with a series or parallel capacitor.

The pick-up controller is an essential part of the technology because it takes power from the receiver pad and provides a controlled output to batteries. It is required to provide an output that remains independent of the load and the separation between pads. Without a controller, the voltage would rise as the gap decreases and fall as the load current increases.

The transmitter pad has been constructed to shield magnetic fields to prevent electrocuting bystanders and the system operates well within internationally agreed limits.

Rolls-Royce Motor Cars has launched the website http://www.electricluxury.com to ignite a global debate around the car. Owners, media and Rolls-Royce enthusiasts are encouraged to contribute, feeding back thoughts, concerns and questions on the use of battery electric technology for super luxury cars.