Expanding Exposure Area Based on Two-Winding Inductor for Magnetic Field Generator to Evaluate Biological Effects

Abstract

There has been an increasing interest in biological effects owing to magnetic field exposure, because wireless power transfer systems for electric vehicles are expected to be widespread in the 85kHz band. Therefore, it is necessary to develop a magnetic field generator and evaluate the biological effects through experimental verification. In particular, the exposure area needs to be expanded for the development of magnetic field generators to offer sufficient number of exposure subjects. This paper presents the design procedure of a two-winding inductor for expanding the exposure area of a magnetic field generator. Two-winding inductors connected in series and in parallel are shown, and circuit configurations using these inductors are presented. It is revealed through impedance analysis that the difference in circuit parameters restricts the operable frequency band in a magnetic field generator with a two-winding inductor connected in parallel. The two-winding inductor connected in parallel can expand the exposure area to 321% of that of a conventional magnetic field generator. Moreover, the validity of impedance analysis is confirmed through the experimental verification rated at 100V.