Dynamic resonant matching circuit for wireless power receivers

A resonant matching circuit for matching a resonant frequency of a wireless power transfer system to a frequency of a power signal, comprising:

• a switch connected in series with a resonant element of the wireless power transfer system;
• and
• a controller connected to the switch and configured to detect crossing of a zero current level of a signal flowing through the resonant element and to open the switch for a predefined amount of time upon detection of the zero current level crossing, wherein opening the switch for the predefined amount of time adds any one of an inductive value and a capacitive value to the resonant frequency of a wireless power transfer system.

A resonant matching circuit for matching a resonant frequency of a capacitive power transfer system to a frequency of a power signal, comprising:

• a switch connected in series with an inductive element of the capacitive power transfer system;
• and
• a controller connected to the switch and configured to detect crossing of a zero current level of a signal flowing through the inductive element and to open the switch for a predefined amount of time upon detection of the zero current level crossing, wherein opening the switch for the predefined amount of time adds any one of an inductive value and a capacitive value to the resonant frequency of the capacitive power transfer system, wherein the resonant frequency is a function of the inductive element, a capacitive impedance formed between receiver electrodes and transmitter electrodes of the capacitive power transfer system, and any one of the inductive value and the capacitive value.

A resonant matching circuit for matching a resonant frequency of a capacitive power transfer system to a frequency of a power signal, comprising:

• a switch connected in parallel with an inductive element of the capacitive power transfer system;
• and
• a controller connected to the switch and configured to detect crossing of a zero voltage level of a signal flowing through the inductive element and to close the switch for a predefined amount of time upon detection of the zero voltage level crossing, wherein dosing the switch for the predefined amount of time adds any one of an inductive value and a capacitive value to the resonant frequency of a wireless power system, wherein the resonant frequency is a function of the inductive element, a capacitive impedance formed between receiver electrodes and transmitter electrodes of the capacitive power transfer system, and any one of the inductive value and the capacitive value.