Design of hybrid‐frequency current source based on multiresonance network

In order to overcome the low efficiency and poor resolution of single‐frequency transmitters for electromagnetic sounding and wireless power transfer (WPT), a well‐organized multifrequency resonant network is proposed to generate a synthetized current with two or more frequencies. The complete design and realization of the hybrid‐frequency current source is presented. The characteristic equation method is applied to extract the resonance frequencies from the given network. On the other hand, the nonlinear equation system about the passive elements is built and solved by the trust–region algorithm based on the expected frequencies. The multifrequency sinusoidal pulse width modulation method is first proposed to create the barcode driving signals for a full‐bridge inverter. The asynchronous modulation is recommended to reduce the harmonic components beyond the resonance frequencies, and the modulation ratios for the driving signals are adjusted at any resonance frequency so that the energy can be distributed evenly at different resonance points. The simulation results prove that almost all energy is concentrated at the resonance frequencies, and the frequency leakage is hardly seen. The resonant network and its control method is very useful to create a hybrid‐frequency current source for high‐efficiency and high‐resolution electromagnetic sounding and WPT. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.