Mobile wireless power transfer system for electric vehicles

A novel Mobile-WPT system was proposed by the authors. Impedance matching circuit is separated from resonator and it becomes controllable by variable capacitors. Also, reflection wave back to power source is suppressed by the combination of a pick-up and a reflector in the receiving unit. To make a gap between transmission line and the receiving unit larger, a microstrip line on an air-substrate with large thickness is introduced. The coupling elements of the receiving unit are designed based on a scaling principle from the previous design for a resin substrate. A demonstration system for miniature vehicles is fabricated. Also, concept of power transfer technology for multiple vehicles is described with simulation results. In addition, dynamic impedance matching circuit is investigated to avoid performance degradation caused by position fluctuation while driving. The total system configuration is illustrated.