News Picks : An electric bus that can recharge wirelessly
23 January 2014
New Scientist: Select bus lines in the UK and Italy are trying out specially designed electric buses that can be recharged without having to connect to cumbersome cables. The system relies on electromagnetic induction, whereby electrical energy is transferred wirelessly via a magnetic field from a coil embedded in the ground to a pickup coil located underneath the vehicle. Based on work by John Boyes and Grant Covic of the University of Auckland in New Zealand, the technology is being adapted by two different companies for use in commercial and, eventually, consumer vehicles. Although wireless power transfer technology was developed decades ago, early devices had low efficiencies and long charging times. Boyes and Covic optimized the shape of the coils to achieve an energy-transfer efficiency of at least 90%. The current buses can get a 120-kW charge in just 10 minutes, and the recharging can be done during scheduled stops.