Inductive Power Transmission DiagramEnlarge Photo
This year we’ve seen a dramatic increase in the number of companies working towards detaching the electric car from its charging cable. Now Toyota, the world’s largest automaker, has joined the inductive charging revolution with a substantial undisclosed investment in WiTricity, specialists in wireless charging.
WiTricity’s current technology is comparable to standard Level 2 fast charge technology, providing up to 3.3 kilowatts of power. This makes it ideal for providing a way of charging plug-in vehicles without wires where in places where wired technology may present a trip hazard such as shopping mall parking lots, for example.
WiTricity’s technology makes use of a technique it calls resonance wireless charging.
Instead of inducing a magnetic field in a receiver coil in the same way a traditional electrical transformer works, resonance inductive coupling works by using two coils which vibrate at the exact same frequency.
When a specific frequency of oscillating current is applied to force the primary coil to vibrate, an oscillating magnetic field of specific frequency is produced, inducing a matching current in the secondary coil as it vibrates sympathetically with the first.
This allows energy to be transferred between two points with very high efficiency without any physical contact between the two coils.
Used primarily in devices like the Powermat to wirelessly charge portable electronics devices, the technology also prevents inadvertent exposure to unintended electromagnetic radiation causing harm. reducing risk to computer components, credit cards and humans.
Toyota’s investment in WiTricity is as yet not fully disclosed, although we expect the partnership to help Toyota develop wireless charging systems for its range of up-coming plug-in vehicles, including future versions of the Plug-in Prius, the all-electric RAV4 EV and possible electrification of its city car, the iQ.