Wireless Power Transfer System
First Claim
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1. A power inverter for driving a transmitter coil in an inductive power transfer system, wherein the inverter is suitable for class ‘
- E’
operation, is arranged to drive a load resistance, and comprises;
a switching device arranged between a power source and ground and arranged to switch at a switching frequency; and
a resonant network arranged in parallel with the switching device between the power source and ground, the resonant network having a resonant frequency which is a non-integer multiple of the switching frequency, such that, in operation, a substantially constant current passes through the load resistance.
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Accused Products
Abstract
A load-independent Class EF inverter may maintain ZVS operation, and produce a constant output current, rather than a constant output voltage, regardless of the load resistance. A constant output current allows the inverter to operate efficiently for a load range from zero resistance (short circuit) to a certain maximum load resistance, making the inverter more suitable as a coil driver for an IPT system. The resonant frequency of the resonant circuit may be tuned to a non-integer multiple of a switching frequency.
4 Citations
27 Claims
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1. A power inverter for driving a transmitter coil in an inductive power transfer system, wherein the inverter is suitable for class ‘
- E’
operation, is arranged to drive a load resistance, and comprises;a switching device arranged between a power source and ground and arranged to switch at a switching frequency; and a resonant network arranged in parallel with the switching device between the power source and ground, the resonant network having a resonant frequency which is a non-integer multiple of the switching frequency, such that, in operation, a substantially constant current passes through the load resistance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of fabricating a power inverter for driving a transmitter coil in an inductive power transfer system, wherein the inverter is suitable for class ‘
- E’
operation, is arranged to drive a load resistance, and the method comprises;
arranging a switching device between a power source and ground;arranging the switching device to switch at a switching frequency; arranging a resonant network in parallel with the switching device between the power source and ground; arranging the resonant network to have a resonant frequency which is a non-integer multiple of the switching frequency, such that, in operation, a substantially constant current passes through the load resistance. - View Dependent Claims (12)
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13. A rectifier for receiving an AC signal from a receiver coil in an inductive power transfer system, wherein the rectifier is suitable for class ‘
- E’
operation, is arranged to drive a load resistance, and comprises;a switching device arranged between a power source and the load resistance and arranged to switch at a switching frequency; and a resonant network having a resonant frequency which is a non-integer multiple of the switching frequency and arranged such that, in operation, a substantially constant current passes through the load resistance. - View Dependent Claims (14, 15)
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16-22. -22. (canceled)
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23. An inductive power transfer system comprising a transmitter circuit and a receiver circuit, the transmitter circuit comprising a power inverter and a rectifier;
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the power inverter being for driving a transmitter coil in an inductive power transfer system, wherein the inverter is suitable for class ‘
E’
operation, is arranged to drive a load resistance, and comprises;a switching device arranged between a power source and ground and arranged to switch at a switching frequency; and a resonant network arranged in parallel with the switching device between the power source and ground, the resonant network having a resonant frequency which is a non-integer multiple of the switching frequency, such that, in operation, a substantially constant current passes through the load resistance; and the rectifier being for receiving an AC signal from a receiver coil in an inductive power transfer system, wherein the rectifier is suitable for class ‘
E’
operation, is arranged to drive a load resistance, and comprises;a switching device arranged between a power source and the load resistance and arranged to switch at a switching frequency; and a resonant network having a resonant frequency which is a non-integer multiple of the switching frequency and arranged such that, in operation, a substantially constant current passes through the load resistance. - View Dependent Claims (24, 25, 27)
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26. A method of fabricating a rectifier for receiving an AC signal from a receiver coil in an inductive power transfer system, wherein the rectifier is suitable for class ‘
- E’
operation, is arranged to drive a load resistance, the method comprising;arranging a switching device between a power source and the load resistance; arranging the switching device to switch at a switching frequency; and arranging a resonant network having a resonant frequency which is a non-integer multiple of the switching frequency, such that, in operation, a substantially constant current passes through the load resistance.
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Specification