Toyota will begin verification testing of its newly developed wireless charging system in late February. Toyota developed the system in cooperation with a company called Witricity, which the automaker has been cooperating with for several years.
Toyota’s Satoshi Ogiso had said earlier in the year that the next-generation Prius Plug-in Hybrid would include a wireless charging option. The idea behind wireless charging is the same we experience with electric toothbrushes and certain mobile phones, it offers the convenience of placing an item close to the charging hub and eliminates the need for direct cable contact with the device .
The charging system transmits electricity by using the magnetic resonance resulting from changes in magnetic field intensity between a transmitting coil on the ground and a receiving coil on the vehicle. It operates at a frequency of 85 kHz, with input voltage of 200 VAC and charging power of 2 kW. The charging time is estimated at about 90 minutes.
The system can reduce drops in power transmission efficiency that can be caused by misalignment or height differences between the transmitting and receiving coils. It is designed to minimize electromagnetic interference on nearby equipment, and the ground-installed transmitting coil is robustly built to withstand a vehicle driving over it.
To enable the driver to park in an optimum charging position, Toyota has developed a new parking assist function that shows the position of the transmitting coil in the parking space. The new function is coupled with Toyota’s Intelligent Parking Assist system.
The one-year verification test will involve three PHEVs in use in homes in Japan, and will assess a number of different issues such as, user satisfaction, ease of use, misalignment rates and charging behaviour. Toyota will also place a strong emphasis on safety and device interference. The results of these tests will determine Toyota’s next move in introducing the concept to the market.