RESONANT POWER SUPPLY WITH SELF TUNING

摘要

This invention relates to current-fed resonant inverters for electrical power applications to change direct current (DC) into alternating current (AC). One application of the invention is to power supplies for inductive power transfer (IPT) systems. There is provided a resonant inverter including an input for supply of current from a DC power source, a resonant circuit including two coupled inductive elements and a tuning capacitance, the inductive elements being arranged to split current from the power source; a first switching means comprising two switching devices operable in substantially opposite phase to alternately switch current from the power source into the inductive elements; and a second switching means to selectively switch one or more control capacitances into or out of the resonant circuit dependent on a power factor of the resonant circuit.