The disclosure features a wireless power transmission system for an elevator that includes at least two wireless power sources disposed at intervals along a wall of an elevator shaft and coupled to a power supply, and at least one wireless power receiving device configured to be mounted to an exterior of an elevator cab and to be coupled to a load onboard the elevator cab, where during operation, the at least two wireless power sources are configured to generate an oscillating magnetic field to transfer wireless energy to the at least one wireless power receiving device.

A feedback controlled coil driver with ASK modulation is disclosed. A class E coil driver drives an LC circuit to generate a magnetic signal via the inductor. A modulation capacitor is coupled to the LC circuit to modulate the coil driver signal. The voltage across the coil driver switch is sampled. The difference between the sampled voltage and a reference voltage is integrated and compared to a ramp voltage to obtain an optimal on time for the coil driver switch such that coil current is maximized.

A hybrid energy storage system is configured to control pulsed power. A first dynamo-electric machine is coupled to an inertial energy storage device and has multiple input stator windings configured to accept input power from a source. A polyphase output stator winding is configured to deliver electric power having a first response time to a DC bus. A secondary energy storage system is coupled to the DC bus and is configured to convert its stored energy to electric power in a bidirectional manner. A second dynamo-electric machine has an input stator winding and at least one polyphase output stator winding coupled to a converter, the converter coupled to a DC output. A polyphase boost exciter is configured to derive energy from the DC bus and excite the second machine input stator winding, wherein the second machine is configured to be excited at a faster rate than the first response time of the first machine.

A method and apparatus for controlling a wireless power transmitter configured to transmit power to a wireless power receiver is provided. The method includes receiving a first signal from the wireless power receiver, wherein the first signal comprises load detection indication bits, detecting a change in load of the wireless power transmitter caused by placement of the wireless power receiver in a charging area of the wireless power transmitter, based on the load detection indication bits, and determining whether to transmit a second signal to the wireless power receiver based on detecting the change in load of the wireless power transmitter.

An approach module determines that a wireless power transfer (“WPT”) secondary pad on a vehicle approaching a WPT primary pad is within an approach distance threshold from the primary pad. A pulse module generates an electrical alignment pulse in the primary or secondary pad in response to determining that the secondary pad is within the approach distance. A measurement module determines an amount of magnetic coupling between the primary pad and the secondary pad, and a feedback module that provides an alignment signal to a driver of the vehicle. The alignment signal represents magnetic coupling. The pulse module continues to provide electrical alignment pulses, the measurement module continues to determine an amount of magnetic coupling in response to the electrical alignment pulses, and the feedback module continues to provide alignment signals indicative of an amount of magnetic coupling as the vehicle moves in relation to the primary pad.

Described herein are embodiments of a source high-Q resonator, optionally coupled to an energy source, a second high-Q resonator, optionally coupled to an energy drain that may be located a distance from the source resonator. A third high-Q resonator, optionally coupled to an energy drain that may be located a distance from the source resonator. The source resonator and at least one of the second resonator and third resonator may be coupled to transfer electromagnetic energy from said source resonator to said at least one of the second resonator and third resonator.

Disclosed is a method for transferring energy wirelessly including transferring energy wirelessly from a first resonator structure to an intermediate resonator structure, wherein the coupling rate between the first resonator structure and the intermediate resonator structure is κ.sub.1B, transferring energy wirelessly from the intermediate resonator structure to a second resonator structure, wherein the coupling rate between the intermediate resonator structure and the second resonator structure is κ.sub.B2, and during the wireless energy transfers, adjusting at least one of the coupling rates κ.sub.1B and κ.sub.B2 to reduce energy accumulation in the intermediate resonator structure and improve wireless energy transfer from the first resonator structure to the second resonator structure through the intermediate resonator structure.

A power reception apparatus includes a plurality of power extraction coils that extract power from a coil being a power supply source, a switch that selects one of the plurality of the power extraction coils and connects the selected power extraction coil to a battery, and a controller that senses a charging state of the battery and changes over the switch. The plurality of the power extraction coils are different from each other in terms of a diameter, the number of turns, or a distance from the coil being the power supply source.

Disclosed herein is a power feeding device including: power transmitting section which transmits electric power by way of a magnetic field; a set of first and second electrodes which are spaced from each other; a power supply which applies a voltage between the first and second electrodes; and a detector which detects whether foreign matter is present on the power transmitting section or not based on the voltage applied by the power supply.

A charging device for a portable device, e.g., in a motor vehicle, includes a resonant circuit, controllable by a trigger device, for inductive transmission of energy to the portable device, wherein the trigger device is designed such that the curve shape of the excitation for the resonant circuit is generated based on an operating state of the charging device.