INDUCTIVE CHARGING

EV wireless charging systems take advantage of the principle of electromagnetic induction to transmit electrical power through the air as a magnetic field. Inductive charging, also referred to as wireless inductive charging, involves the use of a transmitter pad located on, for example, a garage floor. The transmitter pad is connected to a dedicated circuit (e.g., a wall charger as in current approaches). In current wireless inductive charging systems, a receiver pad is installed on the bottom of the vehicle.

THE QKOIL APPROACH

A critical aspect of EV wireless charging systems is the magnetic coupling stage and its configuration for power electronics, efficiency, and transferrable power.  Conventional wireless charging approaches for electric vehicles include the use of a secondary coil attached to the bottom side of the EV and the primary coil placed on the ground.  While this arrangement promotes the necessary flux between the two coils, the gap between the coils can affect energy transfer efficiency.  The QKOIL approach, on the hand, can monitor energy transfer and adjust the gap based on real-time feedback from the battery management system (BMS). In the illustration shown below, the receiving coil may be installed in or on the surface of the EV (e.g., the roof, frunk, etc).

BIDIRECTIONAL CHARGING

Wireless charging of electric vehicles can be achieved with inductive coupling, which involves the transfer of power magnetically rather than by direct electrical contact.  The QKOIL system can also provide for bidirectional inductive charging through the use of a simple circuit that reduces the number of switches and diodes for the inductive charging system, and which regulates current flow in the battery during the charging and discharging phase. An example of a bidirectional inductively coupled battery charging system can involve the use of a fuzzy logic approach.