When it comes to charging systems for electric vehicles, a distinction is made between wired charging systems and wireless charging technology. Wired charging systems and the rapid charging systems based on them currently have greater market acceptance.
As for wireless charging technology, it involves wireless energy transfer using electromagnetic induction or magnetic resonance, as used in the HR-WPT process. In these charging techniques, energy is transferred between a primary coil embedded in the garage floor or parking lot floor and the secondary coil located on the underbody of the vehicle. For optimal energy transfer, the two coils must be positioned exactly on top of each other and spaced as close as possible. Exact alignment of the coils one above the other is ensured by a Tunable Matching Network( TMN), which monitors the operating conditions and efficiency and then aligns the vehicle. Only then does efficient energy transfer take place.
Because the ground clearance of electric vehicles varies, some operate with vertically positionable primary coils that raise once the vehicle is positioned above the coil, minimizing the air gap. To keep the coils from becoming too large and heavy, some work at higher frequencies between 30 kHz and 300 kHz. Such wireless charging systems can transmit power between 400 W and 3.6 kW.
There are also development proposals for the topic of wireless fast charging. For example, the TH Deggendorf has developed an inductive fast charging system for 30 kW as part of a research project. The standardized CHAdeMO charging interface is used as the interface. The wireless fast charging system transmits the energy at 30 kHz.