Magnetic field emission comparison at different quality factors with series-parallel compensation network for wireless power transfer to vehicles

Input current of wireless power transfer system is limited by current rating of power converter on the primary side. Power rating of wireless power transfer system increases linearly with the quality factor for series-parallel topology of the system at a given primary current. Magnetic emissions to the surroundings also increase with increase in the quality factor. In this paper, first analytical expressions are developed for comparing magnetic emissions at different quality factors. Theoretical and simulation (Comsol) results show comparatively lower increase for the magnetic field emissions to the linear increase in the power rating with the quality factor. This paper signifies that at fixed primary current, operation of wireless power transfer system at higher quality factor is favorable with respect to the magnetic emissions.