RESONANT SYSTEM FOR WIRELESS POWER TRANSMISSION TO MULTIPLE RECEIVERS
First Claim
1. A transmitter, comprising:
- an alternating current (AC) power supply;
a resonant circuit receiving power from the AC power supply, including a power transfer coil configured for wireless power transfer;
an impedance-matching circuit; and
a power tracker configured, when the transmitter is magnetically coupled to at least one receiver, to determine a resonant frequency of the at least one receiver.
1 Assignment
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Accused Products
Abstract
In a wireless power transfer system with multiple receivers, receiver management may be necessary to effectively provide power to the multiple receivers. In one implementation, receiver management includes sweeping or stepping the transmitter resonant and/or operating frequency. In another implementation, receiver management includes receiver self-management, in which the receiver load current duty cycle is controlled to maintain receiver voltage even in the presence of multiple receivers. In another implementation, receiver management includes receiver self-management, in which one or more receivers use a time-sharing heuristic to identify when other receivers are charging and wait to begin receiving a transfer of power until another receiver has stopped receiving a transfer of power.
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Citations
23 Claims
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1. A transmitter, comprising:
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an alternating current (AC) power supply; a resonant circuit receiving power from the AC power supply, including a power transfer coil configured for wireless power transfer; an impedance-matching circuit; and a power tracker configured, when the transmitter is magnetically coupled to at least one receiver, to determine a resonant frequency of the at least one receiver. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method, comprising:
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receiving alternating current (AC) power at a power transfer coil in a wireless power transfer receiver; converting the AC power to direct current (DC) power; providing the DC power to a load as a controlled current through the load, the current controlled by varying the duty cycle of a switch to vary the magnitude of the current, thereby varying the effective load of the receiver. - View Dependent Claims (14, 15)
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16. A method, comprising:
- in a first receiver configured to receive a transfer of energy wirelessly from a source,
initializing a counter and starting an incremental count; while the counter is incrementing, if the first receiver determines that another receiver is starting to receive a transfer of energy from the source, reinitializing and restarting the counter; if the first receiver determines that another receiver stops receiving a transfer of energy from the source, ending the incrementing of the count; otherwise, when the counter reaches a predefined end value, ending the incrementing of the count; waiting a random or pseudo-random period; and if the first receiver determines that, during the wait period, no other receiver started to receive a transfer of energy from the source, the first receiver starting to receive a transfer of energy from the source. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
- in a first receiver configured to receive a transfer of energy wirelessly from a source,
Specification