Criteria for Choosing of Resonant Circuit Parameters of Wireless Power Transfer Charging System

Abstract

The promising element of the infrastructure of unmanned electric vehicles is wireless chargers. The central part of such systems is a resonant circuit that provides wireless power transfer. The article discusses a set of criteria used for making the rational choice of the resonant circuit parameters. Such criteria include the efficiency, the current transfer coefficient, the excess voltage on the resonant circuit capacitors over the input voltage, the ratio between the transmitting circuit current and the receiving one. For the resonant circuit with fixed coils size and fixed resonant frequency, the families of curves were obtained via parametric analysis to show how these criteria change depending on the inductance and capacitance of the resonant circuit. The obtained dependencies allow choosing the rational inductances and capacitances of the resonant circuit, providing for a given size and a given value of the input voltage the highest conveyed power with the highest efficiency at the minimum voltage class of capacitors and the minimum current of semiconductor switches. The results of the parametric analysis were confirmed experimentally.