Wireless Power Transfer System
AssigneeImperial Innovations Limited
InventorsPaul Mitcheson, David Yates, Samer Aldhaher
Life of this patent
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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.
Claims21
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.
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.
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.
-22. (canceled)
An inductive power transfer system comprising a transmitter circuit and a receiver circuit, the transmitter circuit comprising a power inverter and a rectifier;
- 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.
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.
Dependencies are inferred from the claim text.