A wireless power supply system includes a power transmission device provided on a ground side and a power receiving device mounted on a vehicle, the power transmission device transmitting, to the power receiving device via a wireless connection, electric power controlled by an inverter circuit, wherein the power receiving device transmits a power supply command signal to the power transmission device in a first cycle by use of a radio signal. The power transmission device includes a power transmission coil current detection means for detecting a power transmission coil current flowing through a power transmission coil and controls an output voltage of the inverter circuit based on the power supply command signal and the power transmission coil current detected by the power transmission coil current detection means in a second cycle shorter than the first cycle.

A wireless sensor assembly that includes a battery pack and a wireless sensor. The battery pack is placed in spaced relation to the wireless sensor and inductively powers the wireless sensor utilizing primary and secondary resonant coils presented within the battery pack and wireless sensor. The wireless sensor additionally has super capacitors therein to continue to operate the wireless sensor during the changing of the battery pack.

The present invention relates to a wireless power supply system including a remote device capable of both transmitting and receiving power wirelessly. The remote device includes a self-driven synchronous rectifier. The wireless power supply system may also include a wireless power supply configured to enter an OFF state in which no power, or substantially no power, is drawn, and to wake from the OFF state in response to receiving power from a remote device.

A contactless power supply device includes a power-transmitting-side pad and a power-receiving-side pad. Each of the power-transmitting-side pad and the power-receiving-side pad has a core and a coil. The core has a plate-shaped yoke portion. The coil has a first coil portion and a second coil portion. The first coil portion is arranged on a top surface of the yoke portion. The second coil portion is arranged along an outer periphery of the yoke portion.

A contactless power supply system includes a first power transmission coil, a plug power reception coil, a plug power transmission coil, and a first power reception coil. The first power transmission coil and the plug power reception coil are configured to satisfy a relational equation of (L.sub.2a/L.sub.1).sup.1/2=G1/K1=N.sub.2a/N.sub.1, where L.sub.1 represents a self-inductance of the first power transmission coil, L.sub.2a represents a self-inductance of the plug power reception coil, N.sub.1 represents a winding number of the first power transmission coil, N.sub.2a represents a winding number of the plug power reception coil, K1 represents a coupling coefficient of the first power transmission coil and the plug power reception coil, and G1 represents a voltage conversion gain of the voltage applied to the plug power transmission coil relative to the voltage applied to the first power transmission coil.

An electrical load driving apparatus, comprising a current distribution apparatus having a power source arranged to deliver an input current into a plurality of branches such that the input current is distributed into a plurality of individual branch currents, wherein each of the plurality of branches includes an inductive arrangement arranged to form an inductive coupling with an associated inductive arrangement of at least one other associated branch, and a plurality of output loads connect to each of the associated branches of the current distribution apparatus.

This invention proposes a method of and a device for transmitting power via electromagnetic coupling from a transmission device to a set of reception devices, said method comprising a step of calculating by the transmission device, a first sum of given power levels defined by each reception device of said set of reception devices; if a maximum power that can be transmitted by the transmission device to said set of reception devices is less than said first sum, then performing a step of determining by said transmission device, based on said first sum and according to a set of criteria, a subset of reception devices among said set of reception devices, to which the transmission device transmits power.

An inductive power transfer system comprises a power transmitter (101) and a power receiver (105). The power transmission system supports two-way communications. The power receiver (105) first initiates a mandatory configuration phase by transmitting a signal strength package and the power transmitter and receiver then operates (505, 507) the mandatory configuration phase wherein a first set of power transfer operating parameters are selected for the power transmitter (101) and the power receiver (105). The power receiver (105) subsequently transmits (509) a request to enter a negotiation phase and the power transmitter (101) acknowledges (511) the request by transmitting an acknowledgement. It then enters the negotiation phase. The power receiver (105) enters the negotiation phase in response to receiving the acknowledgment message. The power receiver (105) and power transmitter (101) then determines (513, 515) a second set of operating parameters by performing the negotiation phase. The approach is particularly suitable for a Qi power transfer system.

Methods and systems for automatically aligning a power-transmitting inductor with a power-receiving inductor. One embodiment includes a method of applying a direct current pulse to a transmit coil of a power-transmitting inductor to attract the power-receiving inductor into alignment along an alignment axis.

Techniques are provided for a multiple-layer planar transformer having center taps of a segmented winding. In an example, a multiple-layer planar transformer can be a coupled inductor circuit including a first winding comprising a conductive coil having an electrical path defining and encircling the central axis, a second winding configured to magnetically couple with the first winding, the second winding having a plurality of individual segments, wherein each individual segment forms a fraction of one turn of the second winding, and a first output inductor coupled to a first common node of the second winding. The first common node can directly couple a first node of a first individual segment of the plurality of individual segments with a first node of a second individual segment of the plurality of individual segments.