System and method for encrypted resonant inductive power transfer

SYSTEM AND METHOD FOR ENCRYPTED RESONANT INDUCTIVE POWER TRANSFER Systems and methods for ensuring that resonant inductive power transfer goes only to authorized users using encryption. Resonant inductive power transfer requires near-identical resonant frequencies in the transmitter and the receiver. The frequency of the power transfer signal changes on a schedule known only to the transmitter (1) and receiver (3) so a "power eavesdropper" cannot track the frequency well enough to efficiently receive power. To make the frequency transitions energetically efficient, a capacitive or inductive element is switched in or out of each circuit at moments of zero-crossing: zero charge on a capacitor or zero current in an inductor. To maintain phase alignment, either switching an inductor (2b) on the transmit side is nearly simultaneous with switching a capacitor (8b) on the receive side, or switching a capacitor (6b) on the transmit side is nearly simultaneous with switching an inductor (4b) on the receive side. BUILD TRANSMITTER AND RECEIVER WITH SWITCHES AND PROGRAM CONTROLLERS SO THAT SWITCHING AN INDUCTOR ON ONE SIDE IS NEARLY SIMULTANEOUS WITH SWITCHING A CAPACITOR ON OTHER SIDE EXCHANGE INFORMATION TO DETERMINE FREQUENCY-CHANGE SEQUENCE POWER UP TRANSMITTER OSCILLATOR TRANSMIT CONTROLLER BEGINS SWITCHING TRANSMITTER FREQUENCY IN ACCORDANCE WITH FREQUENCY-CHANGE SEQUENCE BRING RECEIVER INTO RANGE OF TRANSMITTER RECEIVE CONTROLLER DETECTS PRESENCE OF TRANSMITTER'S OSCILLATING MAGNETIC FIELD RECEIVE CONTROLLER BEGINS SWITCHING RECEIVER FREQUENCY IN ACCORDANCE WITH FREQUENCY-CHANGE SEQUENCE LOAD BEGINS RECEIVING POWER AFTER A FEW CYCLES