Magnetic Stray Field Attenuation in High-Power WPT Systems based on Modular Concept

Threat to public safety due to exposure to high-frequency magnetic field would continue to impede the rapid penetration of wireless charging systems of Electric Vehicles, especially at high power. This paper presents a study on magnetic stray field attenuation based on modular pad design of the high-power wireless charging system. The magnetic stray field generated outside the charging zone was significantly reduced by properly choosing the current distribution among the modular pads. A 30 kW/85 kHz wireless charging system with three channels was developed to examine the radiated flux experienced at 80 cm distance from the center of the charging area. Simulation results reveal that more than 60% reduction can be achieved using 3-channel design when compared against the conventional one-to-one coupler system.