Abstract: A wireless power transfer system comprises a power transmitter generating a wireless power signal providing power to a plurality of power receivers (105, 109). The power transmitter (101) comprises a receiver (203) receiving data messages from the power receivers (105, 109) on a load modulation channel divided into time slots. A time slot processor (205) allocates time slots as dedicated time slots for individual power receivers or as common time slots for load modulation by any power receiver (105, 109). An identity controller (207) links a temporary identity to each of the power receivers (105) and a message processor (209) determines the source power receiver for messages in response to temporary identity information in the messages.

Abstract: A method is presented of allocating communication time slots contained in repeating frames for communication between an inductive wireless power transmitter and at least two inductive wireless power receivers, wherein the power transmitter and the power receivers are arranged to communicate by means of modulation and demodulation of an inductive power signal. The transmitter sends synchronization messages marking the start of the communication time slots and the frames, and messages indicating if a time slot is unallocated. A receiver may send, during an unallocated time slot, send a message to the transmitter requesting allocation of the unallocated communication time slot. The transmitter subsequently sends messages to indicate if the communication was successfully received, and if the allocation request is granted.

Abstract: A wireless power transfer system includes a power transmitter (101) providing power to a power receiver (105) via an inductive power signal. The power transmitter (101) and receiver (105) can operate in different modes including a test mode and a power transfer mode. Operating parameters of the power receiver (105) are constrained in the test mode relative (and specifically the loading). A foreign object detector (209) generates a foreign object detection estimate from a comparison of a measured load to an expected load of the inductive power signal when the power receiver is operating in the test mode. A controller (211) enters the power transmitter (101) and receiver (103) into the power transfer mode when the foreign object detection estimate is indicative of no detection of a foreign object. In the power transfer mode, a parasitic power loss detector (207) generates a parasitic power loss detection for the power transfer if a parasitic power loss estimate is outside a range.

Abstract: A wireless power transfer system includes a power receiver and a power transmitter providing power to this using an inductive power signal. The power transmitter comprises a variable resonance circuit (201) having a variable resonance frequency and generating the inductive power signal. A driver (203) generates the drive signal and a load modulation receiver (303) demodulates load modulation of the inductive power signal. An adaptor (305) adapts the operating frequency and the resonance frequency to converge, and specifically is arranged to control the operating frequency and the resonance frequency to be substantially the same. The adaptation of the operating frequency and the resonance frequency is further in response to a demodulation quality measure. The invention may allow improved communication, and in particular may reduce intermodulation distortion.

Abstract: A power transmitter (101) of a wireless power transfer system comprises a resonance including a transmitter coil (103) for generating a power transfer signal for wirelessly transferring power to a power receiver (105). Further, a driver (1303) generates a drive signal for the resonance circuit (201) and a message receiver (1305) is arranged to receive messages from the power receiver (105). A power loop controller (1307) implements a power control loop by adapting the power of the drive signal in response to power control messages received from the power receiver (105). However, the regulation is subject to a constraint of at least one of a current or voltage of the resonance circuit and a power of the drive signal being below a maximum limit. Further, the power transmitter (101) comprises an adapter (1309) which adapts the maximum limit in response to a load indication indicative of a loading of the power transfer signal by the power receiver (105).

Abstract: A wireless power transfer system includes a power transmitter (101) providing power to a power receiver (105) via an inductive power signal. The power transmitter (101) and receiver (105) can operate in different modes including a test mode and a power transfer mode. Operating parameters of the power receiver (105) are constrained in the test mode relative (and specifically the loading). A foreign object detector (209) generates a foreign object detection estimate from a comparison of a measured load to an expected load of the inductive power signal when the power receiver is operating in the test mode. A controller (211) enters the power transmitter (101) and receiver (103) into the power transfer mode when the foreign object detection estimate is indicative of no detection of a foreign object. In the power transfer mode, a parasitic power loss detector (207) generates a parasitic power loss detection for the power transfer if a parasitic power loss estimate is outside a range.

Abstract: A wireless power transfer system includes a power transmitter (101) arranged to provide a power transfer to a plurality of power receivers (105, 109) via a wireless inductive power signal. T power transmitter (101) comprises a receiver (203) for receiving data messages, load modulated on the wireless inductive power signal and a broadcast transmitter (205) broadcasting on a broadcast communication channel. The power receivers (105) comprise a transmitter (505) for load modulating data message on the power signal. The power transmitter (101) comprises a communication controller (207) which broadcasts first indications indicative of the wireless inductive power signal being available for load modulation in a time interval. A first power receiver comprises a broadcast receiver (507) receiving first indications from the power transmitter (101) and a transmission controller (509) aligning transmissions of data messages with received first indications.

Abstract: A thermal barrier for a wireless power transfer system comprises a first surface area (807) for coupling to a power receiver (111) to be powered by a first electromagnetic signal and a second surface area (805) for coupling to a power transmitter (101) providing a second electromagnetic signal. The thermal barrier (801) further comprises a power repeater (803) with a resonance circuit including an inductor and a capacitor. The power repeater (803) is arranged to generate the first electromagnetic signal by concentrating energy of the second electromagnetic signal towards the first surface area (807). The thermal barrier may provide thermal protection of the power transmitter (101) without unacceptable impact on the power transfer operation.

Abstract: A method of encoding data packet by encoding type information and size information of the data packet into the same field. The data packet comprises a header part and a message part. The header part comprises at least one bit for indicating the type of the data packet, where the method includes obtaining the size information of the data packet based on the at least one bit.

Abstract: An inductive wireless power transmitter is presented for transmitting an inductive wireless power signal to at least two inductive wireless power receivers. The power transmitter coordinates communication with the power receivers in time slots. It allocates a measurement time slot for synchronised power measurement by the power transmitter and the power receivers. During the measurement time slot the power transmitter measures the amount of power it transmits. After the end of the measurement time slot it receives from the power receivers the measured amounts of power received. From the measured power transmitted and power received, it determines an amount of power lost. If the amount of power lost exceeds a threshold value, it reduces the power of the inductive wireless power signal.

Abstract: A wireless power transfer system includes a power receiver and a power transmitter providing power to this using an inductive power signal. The power transmitter comprises a variable resonance circuit (201) having a variable resonance frequency and generating the inductive power signal. A driver (203) generates the drive signal and a load modulation receiver (303) demodulates load modulation of the inductive power signal. An adaptor (305) adapts the operating frequency and the resonance frequency to converge, and specifically is arranged to control the operating frequency and the resonance frequency to be substantially the same. The adaptation of the operating frequency and the resonance frequency is further in response to a demodulation quality measure. The invention may allow improved communication, and in particular may reduce intermodulation distortion.

Abstract: An inductive power transmitter device for inductively providing power to a mobile device provided with a receiver coil unit is disclosed. The transmitter device comprises a holder and a coil arrangement. The holder has a cavity defined by two walls providing facing surfaces, wherein the cavity is configured for receiving the mobile device between these facing surfaces. The coil arrangement has two transmitter coil units, wherein one of these coil units is arranged into one of said walls and the other of these transmitter coil units is arranged into the other of said walls, and wherein each of the coil units is configured for inductively coupling to the receiver coil unit of the mobile device when inserted into the cavity of the holder. These features allow a user to connect the mobile device to the transmitter device without being worried about the right position of the mobile device.

Abstract: A method is presented of allocating communication time slots contained in repeating frames for communication between an inductive wireless power transmitter and at least two inductive wireless power receivers, wherein the power transmitter and the power receivers are arranged to communicate by means of modulation and demodulation of an inductive power signal. The transmitter sends synchronization messages marking the start of the communication time slots and the frames, and messages indicating if a time slot is unallocated. A receiver may send, during an unallocated time slot, send a message to the transmitter requesting allocation of the unallocated communication time slot. The transmitter subsequently sends messages to indicate if the communication was successfully received, and if the allocation request is granted.

Abstract: An authentication method authenticates a first party to a second party, where an operation is performed on condition that the authentication succeeds. If the first party is not authenticated, then if the first party qualifies for a sub-authorization, the operation is still performed. Further, a device that includes a first memory area holding a comparison measure, which is associated with time, and which is also used in said authentication procedure, a second memory area holding a limited list of other parties which have been involved in an authentication procedure with the device, and a third memory area, holding compliance certificates concerning parties of said list.

Abstract: An inductive power transmitter device provides power to a mobile device with a receiver coil. The transmitter device comprises a holder and a coil arrangement. The holder has a cavity defined by two walls, where the cavity is configured for receiving the mobile device between those surfaces. The coil arrangement has two transmitter coil units, where one of the coil units is arranged into one of the walls and the other transmitter coil unit is arranged into the other wall. Each of the coil units is configured for inductively coupling to the receiver coil of the mobile device when inserted into the cavity of the holder.

Abstract: A wireless power transfer system comprises a power transmitter generating a wireless power signal providing power to a plurality of power receivers (105, 109). The power transmitter (101) comprises a receiver (203) receiving data messages from the power receivers (105, 109) on a load modulation channel divided into time slots. A time slot processor (205) allocates time slots as dedicated time slots for individual power receivers or as common time slots for load modulation by any power receiver (105, 109). An identity controller (207) links a temporary identity to each of the power receivers (105) and a message processor (209) determines the source power receiver for messages in response to temporary identity information in the messages.

Abstract: 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.

Abstract: A wireless power transfer system includes a power receiver and a power transmitter providing power using an inductive power signal. The power transmitter comprises a resonance circuit (201) comprising a capacitive impedance (503) and an inductive impedance (501). A driver (203) generates a drive signal for the resonance circuit. A frequency modification circuit (505) controls the resonance frequency of the resonance circuit (201) by slowing a state change for at least one of the capacitive impedance (503) and the inductive impedance (501) for a fractional time interval of at least some cycles of the drive signal. The frequency modification circuit (505) is arranged to align at least one of a start time and an end time for the fractional time interval to transitions of a timing signal. In the power transmitter, the driver (203) generates the timing signal to have transitions synchronized to the drive signal. The slowing may be by impeding current flow between the capacitive and inductive impedance (503, 501).

Abstract: A wireless power transfer system includes a power transmitter (101) arranged to provide a power transfer to a plurality of power receivers (105, 109) via a wireless inductive power signal. T power transmitter (101) comprises a receiver (203) for receiving data messages, load modulated on the wireless inductive power signal and a broadcast transmitter (205) broadcasting on a broadcast communication channel. The power receivers (105) comprise a transmitter (505) for load modulating data message on the power signal. The power transmitter (101) comprises a communication controller (207) which broadcasts first indications indicative of the wireless inductive power signal being available for load modulation in a time interval. A first power receiver comprises a broadcast receiver (507) receiving first indications from the power transmitter (101) and a transmission controller (509) aligning transmissions of data messages with received first indications.

Abstract: A wireless power transfer system includes a power transmitter (101) providing power to a power receiver (105) via an inductive power signal. The power transmitter (101) and receiver (105) can operate in different modes including a test mode and a power transfer mode. Operating parameters of the power receiver (105) are constrained in the test mode relative (and specifically the loading). A foreign object detector (209) generates a foreign object detection estimate from a comparison of a measured load to an expected load of the inductive power signal when the power receiver is operating in the test mode. A controller (211) enters the power transmitter (101) and receiver (103) into the power transfer mode when the foreign object detection estimate is indicative of no detection of a foreign object. In the power transfer mode, a parasitic power loss detector (207) generates a parasitic power loss detection for the power transfer if a parasitic power loss estimate is outside a range.