Adjusting the frequency of an autonomous push pull converter for wireless power transfer by varying the equivalent resonant capacitance through balanced DC voltage control

摘要

This paper proposes a full bridge capacitor matrix circuit with two capacitors in parallel with two diodes. The conduction periods of the diodes is controlled by a DC voltage so that the equivalent capacitance of the circuit can be varied. The proposed `variable' capacitor can be used for circuit tuning of various resonant power converters, for example to adjust the operating frequency of autonomous push pull converters for wireless power transfer. This method has many advantages over traditional switching mode capacitors and inductors methods, because it can achieve switching-free smooth operation with accurate adjustment of resonant conditions for high frequency operation.