Protection circuits for wireless power receivers
AssigneeWiTricity Corporation
InventorsMilisav Danilovic, Conor Rochford
Life of this patent
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Abstract
Exemplary protection circuitry for wireless power systems can include a battery disconnect circuit, a load dump protection circuit, and/or a coil disconnect circuit. One or more of these protection circuits may be employed by a wireless power receiver. Further, one or more of these protection circuits may enable a wireless power receiver to be able to protect itself independently from a wireless power transmitter, thereby increasing safety of the wireless power system.
Claims22
A method for protecting a wireless power receiver while the receiver is energized during wireless power transmission, the wireless power receiver comprising a resonator coil coupled to an impedance circuit and a rectifier comprising at least one transistor, the impedance circuit comprising (i) a first set of capacitors coupled in series with the resonator coil;
- (ii) a second set of capacitors coupled in parallel with the resonator coil;
- and (iii) at least one inductor coupled between the second set of capacitors and an input of the rectifier, the method comprising:
- while the receiver is energized, turning on the at least one transistor such that a coil current in the resonator coil is reduced to zero or near zero Amperes;
- and
- opening, after a period of time, at least one relay coupled to or within the impedance circuit such that the coil current and an input current to the rectifier are reduced to zero or near zero Amperes, thereby isolating the resonator coil from a remainder of the receiver and preventing overheating in the receiver.
A protection circuit for a wireless power receiver while the receiver is energized during wireless power transmission, the receiver comprising a resonator coil coupled to an impedance circuit and a rectifier comprising at least one transistor, the impedance circuit comprising (i) a first set of capacitors coupled in series with the resonator coil;
- (ii) a second set of capacitors coupled in parallel with the resonator coil;
- and (iii) at least one inductor coupled between the second set of capacitors and an input of the rectifier, the protection circuit comprising:
- the at least one transistor is configured to turn on, while the receiver is energized, such that a coil current in the resonator coil is reduced to zero or near zero Amperes;
- and
- at least one relay coupled to or within the impedance circuit, the relay configured to such that the coil current and the input current are reduced to zero or near zero Amperes, thereby isolating the resonator coil from a remainder of the receiver and preventing overheating in the receiver.
A wireless power receiver comprising:
- a resonator coil configured to inductively receive power;
- a rectifier coupled to the impedance circuit, the rectifier comprising at least one low-side transistor;
- an impedance circuit coupled between the resonator coil and the rectifier, the impedance circuit comprising (i) a first set of capacitors coupled in series with the resonator coil;
- (ii) a second set of capacitors coupled in parallel with the resonator coil;
- and (iii) at least one inductor coupled between the second set of capacitors and an input of the rectifier;
- at least one relay coupled to or within the impedance circuit, wherein:
- while the receiver is energized, the at least one transistor is configured to be turned on such that the coil current in the resonator coil is reduced to zero or near zero Amperes, and
- the at least one relay is configured to open, after a period of time after the transistor is turned on, such that the coil current and an input current to the rectifier are reduced to zero or near zero Amperes, thereby isolating the resonator coil from a remainder of the receiver and preventing overheating in the receiver.
Dependencies are inferred from the claim text.