An inductive power transfer system (1) comprises a primary unit (10) operable to generate an electromagnetic field and at least one secondary device (30), separable from the primary unit, and adapted to couple with the field when the secondary device is in proximity to the primary unit so that power can be received inductively by the secondary device from the primary unit without direct electrical conductive contacts therebetween. The system detects if there is a substantial difference between, on the one hand, a power drawn from the primary unit and, on the other hand, a power required by the secondary device or, if there is more than one secondary device, a combined power required by the secondary devices. Following such detection, the system restricts or stops the inductive power supply from the primary unit. Such a system can detect the presence of unwanted parasitic loads in the vicinity of the primary unit reliably.

Controlling inductive power transfer systems

A wireless power infrastructure for delivering wireless power from a wireless network to mobile devices. The infrastructure includes a plurality of power transmission hubs, each hub having: a first capacitor for transmitting a signature frequency for a defined range; and a set of second capacitors, each for transmitting resonant wireless power within the defined range at a selectable frequency. A mobile device for obtaining wireless resonant the plurality of power transmission hubs is also described, and includes: a first variable capacitor for detecting a signature frequency associated with a proximately located power transmission hub; a second variable capacitor for receiving wireless resonant capacitor from the proximately located power transmission hub; and a synchronization system for setting the second variable capacitor to a frequency that is synchronized with a wireless resonant power transmission of the proximately located power transmission hub.

Wireless power infrastructure

The invention provides a power delivery system for a mobile device. The power delivery system includes a contactor device and a plurality of first electrical contacts on the contactor device disposed in an interspersed arrangement wherein first electrical contacts of one polarity are interspersed with first electrical contacts of a second polarity throughout the contactor body.

Alternative wirefree mobile device power supply method and system with free positioning

A non-contact power charging, in which power transmission can be interrupted when foreign materials are deposited on a charge plate of the non-contact power charging system. A charging operation can be continuously maintained at a stable voltage even if a non-contact power receiving apparatus moves by touching or displacement on the charge plate of the non-contact power charging system in the charging operation. Charging efficiency is improved.

Non-contact power charging system and control method thereof

An inductive wireless power system using an array of coils with the ability to dynamically select which coils are energized. The coil array can determine the position of and provide power to one or more portable electronic devices positioned on the charging surface. The coils in the array may be connected with series resonant capacitors so that regardless of the number of coils selected, the resonance point is generally maintained. The coil array can provide spatial freedom, decrease power delivered to parasitic loads, and increase power transfer efficiency to the portable electronic devices.

Selectable coil array

Apparatus for transferring electrical power between a power supplying apparatus and power consuming apparatus and having a separable high frequency transformer with a primary permanently mounted to the power supply apparatus and a secondary mounted about the power consuming apparatus A charging control circuit mounted on the consuming apparatus, eg a mobile vehicle includes means for detecting current and voltage delivered through the transformer, and also for monitoring storage batteries within the vehicle The power supply apparatus includes a power supply circuit comprising a ferrite core transformer and capacitor forming a parallel resonant circuit The primaries of the transformer are alternately driven by a driver about opposing polarities The drivers are controlled by a voltage-controlled pulse-width modulator which provides a square wave input to the drivers to cause them to alternatively energize the ferrite core transformer Power is transferred across the inductor to the resonant circuit as portions of a sine wave The power supply circuit also includes an internal current sensing circuit to shut current build-up down when current in the resonant circuit becomes too high, and an external control loop which senses power demands of the charging control circuit delivered via an optical communications link within the separable transformer

J. Kirkwood H. Rough

Papers

Power transfer device