Wireless Charging

The Korea Advanced Institute of Science and Technology (KAIST) and the Korea Railroad Research Institute (KRRI) have developed a wireless power transfer technology that can supply 180 kW of power at 60 kHz. KAIST first tested its On-line Electric Vehicle (OLEV) in 2009, and has made substantial improvements in size and charging power since then.

Last week, KAIST and KRRI demonstrated the wireless technology to the public by testing it on the railroad tracks at Osong Station in Korea. The test vehicles, a bus and a tram, receive power at an 85% transmission efficiency rate while maintaining a 20 cm air gap between the underbody of the vehicle and the road surface. In July 2013, the researchers plan to test OLEV on a public street in the city of Gumi.

Professor Dong-Ho Cho of KAIST said, “We have greatly improved the OLEV technology from the early development stage by increasing its power transmission density by more than three times. The size and weight of the power pickup modules have been reduced as well. We were able to cut down the production costs for major OLEV components, the power supply, and the pickup system, and in turn, OLEV is one step closer to being commercialized.”

Image: KAIST
Source: KAIST via Phys.org

New wireless EV charging systems are cropping up like new kitchen gadgets for Christmas. Most systems now available or in real-world testing, such as Evatran’s Plugless Power and Qualcomm’s Halo, use a charging pad that can be mounted on the surface of a parking space, or embedded underneath the asphalt or concrete. However, this isn’t a perfect solution. A surface-mounted pad can get in the way, and embedding a pad requires some additional trouble and expense (and in some locations, such as multi-story garages, may not be practical at all).

Miami-based Car Charging Group, Inc. (OTCQB: CCGI) has come up with a solution - embedding the inductive charging apparatus in a “parking bumper.” What CarCharging calls a bumper, and others call a chock or wheel stop, is an oblong piece of concrete, wood or plastic that is common in parking facilities around the world. With a transmitter in this item, and a receiver in the car’s bumper, a driver need only pull up so that the wheels rest against the stop, and the vehicle is perfectly aligned for charging.

"While current inductive charging options have eliminated the station's plug in cord, they add alignment issues between the charging station and the EV, and installations can be extremely expensive, if not impossible," said Michael D. Farkas, CEO of CarCharging. "To reduce these obstacles, we believe that the energy source for the charge should be placed in the parking bumper. The parking bumper is already standard to most parking lots, and it eases permitting issues because the installation is easier and the appearance of the parking spot is unchanged."

CarCharging is focused on the design and placement of the charging station, rather than the energy transfer technology involved, and plans to adapt its design to integrate with the magnetic coupling technology offered by Qualcomm, Delphi, Siemens, Evatran and others. It announced the filing of a utility patent application (#13600058) with the United States Patent and Trademark Office for the idea, and intends to incorporate the wireless charging standard currently being developed by the Society of Automotive Engineers.

Soucre: CarCharging Group

As it becomes clearer that wireless charging is the wave of the future, alternate ways of accomplishing it are beginning to emerge. Most of the systems now available or in real-world testing, such as Evatran’s Plugless Power and Qualcomm’s Halo, work by means of electromagnetic induction. However, researchers at the University of British Columbia (UBC) have developed a new type of wireless charging system based on magneto-dynamic coupling, which they believe offers several advantages.

UBC’s system uses a rotating permanent magnet in the transmitting unit to cause a second magnet in the receiving unit to rotate as well, generating an electric current.

According to the UBC team, their system can transfer power across a wide air gap at more than 90% efficiency, power can be transferred through metal without significant loss of performance, and the system is tolerant of misalignment, so there’s no need to line up the transmitter and receiver precisely. Wiring and components are simple and low-cost. Power transfer occurs at a low frequency and in a localized area, so there is almost no risk of interference with other high-frequency wireless devices, and potential health risks of exposure to high-frequency electromagnetic fields are not a factor.

The team has successfully demonstrated their system in a fleet of EVs run by UBC Building Operations, with the support of a grant from the Natural Sciences and Engineering Research Council of Canada. This fully automated system performed successfully in a variety of weather conditions including snow, rain and sub-zero temperatures.

Source: UCB via Green Car Congress

The city of Milton Keynes in the UK has become the latest to plan a deployment of electric buses. The modernist “forest city” will replace the diesel buses on one route with eight electric buses that will use wireless charging. The route currently transports more than 775,000 passengers a year over a total of 450,000 miles. Electrification is expected to remove approximately 500 tons of tailpipe CO₂ emissions per year, and reduce running costs by between £12,000 and £15,000 per year.

The trial, which will begin in summer 2013, will be managed by a joint venture called MBK Arup Sustainable Projects, led by a subsidiary of Mitsui & Co. Europe. The goal is to use the data collected to demonstrate the economic viability of low-carbon public transport.

The buses will charge when power transmitted from a primary coil buried in the road is picked up by a secondary coil on the bus. 10 minutes parked over a coil will replenish two thirds of the energy consumed by the bus’s route. The primary coils will be placed at three points on the bus route, and the buses will charge in the time scheduled for driver breaks at the end of the route.

John Miles of Arup said, “What makes the Milton Keynes project different to other electric bus schemes is the wireless charging system. The Milton Keynes buses will be able to cover a heavily-used urban route because they are able to charge for 10 minutes at the beginning and end of each cycle without interrupting the timetable. This means that for the first time, an electric bus will effectively be able to do everything a diesel bus can do, which is a significant step forwards to a cleaner, quieter, public transport system.”

Noriaki Sakamoto, Managing Director, Mitsui & Co. Europe, said, “Since the withdrawal of the subsidy for diesel buses, we can see that the cost of diesel bus operations will rise significantly. This, coupled with the anticipated reduction in the cost of batteries and electric drive systems for buses, as well as the introduction of wirelessly charging during the day now means that the electric bus is now a real contender in the future of public transport. Innovation and trials are urgently needed to find a new way forward and Mitsui, as a business enabler, is happy to back this innovative initiative because we can see the long-term benefit for the community as well as for Mitsui.”

Source: Mitsui & Co. Europe Plc
Image: ReeSaunders

Evatran, the developer of Plugless Power wireless EV charging equipment, will host a launch event for its modestly-named Apollo Program on February 23 in Richmond, Virginia. Governor Bob McDonnell will host the event, which will include a demonstration of the wireless charging technology on a Nissan LEAF, as well as EV test drives for Virginia’s movers and shakers.

Evatran’s Apollo Launch Program will follow several commercial fleet operators around the country for three months as they try out Plugless Power wireless chargers with their LEAFs and Volts.

"This is an important moment in time for the electric vehicle. We believe that the widespread adoption of these cars requires enabling technologies, like Plugless Power, to come to market," said Evatran CEO Thomas Hough. "Bringing these technologies to all electric vehicle owners, however, requires industry leaders to step forward to trial prototypes - we are excited to celebrate the involvement of these partners during our Apollo Launch Event."

Image: Evatran

Wireless charging, which is now available for both the Leaf and the Volt, is a great convenience, and one of the hottest trends on today’s EV scene. Mobile wireless charging, which would allow an EV to charge while rolling down a highway, has the potential to radically transform our entire transportation system. A Stanford University research team has designed a system that could do just that, and has published its findings this week in the journal Applied Physics Letters. The researchers have tested the system using computer models – building a prototype is the next step.

Wireless power transfer is based on a technology called magnetic resonance coupling. Two copper coils are tuned to resonate at the same natural frequency, and placed a few feet apart. The Stanford team’s system can transfer 10 kW of power over a distance of 6.5 feet – enough to charge a car moving at highway speeds – and has an efficiency of 97 percent.

"Our vision is that you'll be able to drive onto any highway and charge your car," said Professor Shanhui Fan. "Large-scale deployment would involve revamping the entire highway system and could even have applications beyond transportation."

Mathematical simulations indicate that the system won't affect drivers, passengers or the microcomputers that control steering, navigation and other vehicle operations. "Wireless power transfer will only occur if the two resonators are in tune. Objects tuned at different frequencies will not be affected," says Fan.

Wireless technology might also one day assist GPS navigation of driverless cars. Since the charging coils would be in the center of the lane, they could provide precise positioning at no extra cost.

Image: Standford

Qualcomm and Transport for London are cooperating on a trial program in which fifty EVs will test wireless recharging systems in Cool Britannia’s capital, Auto Express News reported this week. The test will last two years, and the company envisions public wireless chargers going online at UK car parks, offices and shopping centers in 2014.

Qualcomm’s inductive charging system transfers energy from an iPad-size plate on or under the roadway to another plate on the underside of an EV. Wireless chargers are not only more convenient than plug-in posts – they also reduce street clutter and the risk of theft or vandalism. Currently, the car has to be parked to fill up, but some day recharging points could be embedded in roads, banishing range anxiety for good.

Qualcomm, the world's largest chipmaker, has been a major investor in wireless power R&D, and acquired charging technology provider HaloIPT earlier this year. The company claims its wireless system beats the competition, because it works over a wider air gap between car and charging plate.

“The system works on the principle of a magnetic resistance similar to charging an electric toothbrush,” said Qualcomm’s Joe Barret. “The advantage of our system is that even if you're not very good at parking it will still work. In future you could have pads buried in the motorway every metre, which would allow electric cars to travel longer distances, have smaller batteries and weigh less.”

Image: HaloIPT

EV-related consortia and alliances are bubbling up like alphabet soup. At this week’s Consumer Electronics Show (CES), the Institute of Electrical and Electronics Engineers (IEEE) announced the formation of the Power Matters Alliance (PMA), whose mission is to develop standards for delivering power and energy services to consumer and automotive electronics systems.

A new suite of standards called Power 2.0 will reference existing standards and define gaps that new standards will address, covering areas such as wireless charging, mobile computing, smart batteries, household power and power in public places. Group members include Duracell, Facebook, Google, General Motors and Powermat.

"The Power 2.0 specification will enable developers to create applications and services atop our wireless power platform," said Chris Thibodeau of GM. "We look forward to working with the rest of the industry to ensure that Power 2.0 becomes the standard across the automotive sector worldwide."

"The PMA could open the door for managed power," said Bruce Nordman, a researcher at Lawrence Berkeley National Laboratory. "We can reinvent our electricity from the bottom up, with nanogrids for a system architecture modeled on Internet principles so that a table with embedded wireless power could act as a nanogrid, and so can a car," he added.

Image: HaloIPT