Analytical Equivalent Circuit Model for Series-Compensated Wireless Power Transfer Systems

Wireless power transfer systems are characterized by a loosely coupled magnetic circuit and a power electronics interface. For the optimization of the system power factor, a compensation circuit composed of capacitors is adopted to form a resonant tank with the power coil. The behavior of the overall circuit in terms of power transfer and current/voltage waveform depends on several parameters, which can make the analysis and optimization of the system complex. This paper proposes an analytical derivation of an equivalent RLC system that greatly simplify the design in terms of Zero Voltage Switching (ZVS) regions. In addition to this, the RLC equivalent circuit allows an easy analytic calculation of the output power depending on all WPT system parameters. The analytical model will be validated by simulation results.