Capacitive wireless power transfer by means of adaptive matching networks

A controlled wireless Capacitive Power Transfer (CPT) system, based on adaptive matching networks, comprising:

• a) a primary power transmitter side for wirelessly transmitting power to a secondary power receiver side via coupling plates having mutual capacitance CM,
• said primary power transmitter side comprising:
• a.1) a power source connected to a power driver operating at a determined switching frequency fsw;
• a.2) a primary adaptive matching network comprised of a primary resonant circuit with a bias-controlled variable primary inductor serially connected to said mutual capacitance CM and a capacitor parallelly connected to said mutual capacitance CM, for regulating the current flowing to said secondary side via said mutual capacitance CM;
• and
• a.3) a primary controller comprised of:
• a.3.1) a first control loop, for adjusting the switching frequency fsw to compensate for changes in the-impedance of said primary adaptive matching network, whenever said mutual capacitance CM changes;
• a.3.1) a second control loop, for adjusting a resonant frequency of said primary resonant circuit to track the switching frequency fsw by providing appropriate bias to said primary inductor and changing the resonant frequency of said primary resonant circuit;
• and
• said secondary power receiver side comprising:
• b.1) a rectifier circuit connected to a load and operating at a resonant frequency of said primary resonant circuit;
• b.2) a secondary adaptive matching network connecting between said mutual capacitance CM and said rectifier circuit and comprising a secondary resonant circuit with a bias-controlled variable secondary inductor serially connected to said mutual capacitance CM and a capacitor parallelly connected to said mutual capacitance CM, for matching an impedance of said secondary adaptive matching network;
• b.3) a secondary controller comprised of:
• b.3.1) a control loop, for adjusting the impedance of said secondary adaptive matching network to match the resonant frequency of said primary resonant circuit by providing appropriate bias to said secondary inductor.