Inductive power and data transfer using energy injection

Inventors

Budgett, David Mortimer • Malpas, Simon Charles • LEUNG, Dixon Pok Chung • GALLICHAN, Robert John • Wright, Bryon Elmer • McCormick, John Daniel

Assignees

Auckland Uniservices Ltd

Abstract

A wireless power transfer secondary or pick-up has a resonant circuit and a switch connected to the resonant circuit operable to produce a phase shift in an oscillating voltage or current in the resonant circuit. A controller is configured to operate the switch to introduce one or more controlled phase shifts in the oscillating voltage or current in the resonant circuit which encode data for detection by a coupled circuit.

Core Innovation

The invention provides a wireless power and data transfer system that transfers power during a first interval and then decodes data in a second interval in which the primary resonant circuit is not transferring power. The primary controller controls power transfer in the first interval and operates a phase detector to decode data in the second interval using a phase modulation produced by the pick-up resonant circuit.

The pick-up resonant circuit includes an inductor and a capacitor configured to receive power wirelessly from the primary resonant circuit, and an energy storage element configured to store energy received by the pick-up resonant circuit. A driving circuit drives resonant current and voltage in the pick-up resonant circuit, while a phase modulator activates and deactivates a switch to encode data through phase modulation of the resonant voltage or current for detection by the phase detector.

The phase modulator activates the switch either to short circuit the inductor at maximum current and zero voltage across the capacitor, or to open circuit the capacitor at maximum voltage and zero current in the inductor, for a first time period comprising a fraction of a resonant cycle. After the first time period elapses, the phase modulator deactivates the switch to maintain the resonant current and voltage at a new phase, waits for a second period of time corresponding to a plurality of cycles to elapse, and then reactivates the switch, while the primary phase detector detects the resulting phase shift.

A further aspect controls the system by stopping power transfer from the primary at an end of the first interval, and in the second interval supplying energy from an energy storage element to the pick-up resonant circuit to drive resonant current and voltage without transmitting power from the primary. Data encoding is performed by phase modulation of the resonant voltage or current using switch activation and deactivation for the fraction of a resonant cycle, and the primary apparatus detects the phase shift via the phase detector.

Claims Coverage

Two independent claims are identified. They cover a wireless power and data transfer system and a corresponding control method, each centered on phase modulation of a pick-up resonant circuit using switch activation/deactivation for a fraction of a resonant cycle while a phase detector detects a resulting phase shift during a subsequent interval without primary power transfer.

Across the independent claims, the core inventive coverage centers on using a phase detector to decode data during a second interval without primary power transfer, while the pick-up resonant circuit encodes data by activating/deactivating a switch for a fraction of a resonant cycle to create and maintain controlled phase shifts, optionally with threshold-based enable/disable logic and with driving from an energy storage element after stopping power transfer.

Stated Advantages

Documented Applications