Pulling Wires for Wireless
The discussion surrounding electric vehicles has been about getting more wires out on the street for EVSE equipment, but slowly the trend is going for less wires and looking at wireless power transfer. The trend has come a long way since it first appeared at a TED in 2009.
Last week KAIST made some big splashes in the news again with their latest development. KAIST is now testing their wirelessly charged busses in an actual urban environment, in the South Korean city of Gumi. Previously test runs have been done at an amusement park and at KAIST's campus.
What is new about KAIST's project now is they are using wires instead of the conventional coils. Competitors have so far all used magnetic coils to transfer power from the surface of the road into the vehicle. Now KAIST can do the same, but with a set of cables. The main advantage is installation costs and time. The main benefits for cables has been explained to me about a year ago by professor Pavol Bauer from TU Delft; putting a large number of coils in the road requires you to break open a large area of road. Putting a cable in you can achieve by just milling a long slot to put the cable in; a lot cheaper and quicker!
- Can charge on the go
- No fiddling with cables at stops
- Can use smaller battery
- Lighter bus
- More room/capacity for passengers
- Cables are easier to install
- ables are cheaper to install
- Only 5-15% road surface required
- 85% transfer efficiency achieved
The concept of electric vehicles that can go on forever while being charged wirelessly is very appealing; instead of having to stop the race after the batteries are drained, you can drive a full Le Mans on electricity! It was to my amazement that back in 2011 the FIA had not fully considered inductive charging as an option to race with for their (then) upcoming Formula E Championship. I was even more delighted when I got the opportunity to come over to Paris and explain in person the pros and cons of such an inductive charged race to them. The inductive race did not make it (yet) for the Formula E Championship, but one team does look promising for this technology: Drayson Racing.
Drayson Racing was one of the first teams to sign on with the Formula E, they have made headlines with their World Record and they can charge their battery wirelessly with Qualcomm Halo technology. Their aim is to have a full inductive race.
While the Formula E is staged for city races and inductive technology is not that widely available yet, being able to get a race track ready by simply installing a few cables is much easier to accomplish than digging up the city and installing a lot of coils to get the same effect.