Abstract: The power transmitter (101) providing power to a power receiver (105) comprises a communicator (309) communicating with the power receiver (105) and a negotiator (305) negotiating a guaranteed power level with the power receiver (105) prior to a power transfer phase. The guaranteed power level is a minimum power level guaranteed by the power transmitter (101) throughout the power transfer phase. During the power transfer phase, a determiner (307) dynamically determines an available power level based on the prevailing operating parameters. The available power level is one that can currently be provided but is not guaranteed. The power controller (309) is arranged to, during the power transfer phase, increase the power level above the guaranteed minimum level in response to power control messages, and to reduce the power level regardless of the power control messages in response to a detection that the power level exceeds the available power level.

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 inductive power transfer system comprises a power transmitter for transmitting power inductively to a power receiver via transmitter coil 11 to receiver coil 21. In the system, a communication method comprises a step 37 of transmitting, by the power receiver, first data and second data to the power transmitter, the first data indicating a modulation requirement, and the second data indicating an inquiry message; a step 32 for receiving, by the power transmitter, the first data and the second data from the power receiver; a step 34 for transmitting, by the power transmitter, a response message for responding to said inquiry message, by modulating a power signal according to said modulation requirement so as to carry the response message; and a step 35 for receiving the response message by the power receiver by demodulating the modulated power signal carrying the response message received via the receiver coil from the power transmitter.

Abstract: In a wireless optical network with multiple coordinators or other access points, the coverage area of coordinators may overlap. Interference in the communication between coordinators and devices may occur in these overlapping coverage areas. Various embodiments propose an automatic allocation of reserved time slots to coordinators. These time slots support the coordinators to advertise their presence without interference and enable device to detect the presence of a neighbour coordinator in a single MAC cycle. Fast detection allows fast re-scheduling of time slots in the wireless optical network in order to prevent interference when a device that enters the overlapping coverage area of two coordinators.

Abstract: A power transmitter (101) of a wireless power transfer system provides wireless power to a power receiver (105). The power transmitter (101) comprises a variable resonance circuit (201) generating an inductive power transfer signal in response to a drive signal. The resonance circuit comprises a capacitive and inductive impedance (201, 203), at least one of which is variable. The resonance frequency can be varied by at least one of the impedances being variable in response to a control signal. A driver (205) generates the drive signal with a variable drive frequency. A frequency modulator (305) applies frequency modulation to the drive signal by varying the variable drive frequency in response to data values to be transmitted to the power receiver (105). An adapter (309) generates the control signal in response to the data values such that the variable resonance frequency follows the variations in the drive frequency resulting from the frequency modulation of the drive signal.

Abstract: In a wireless optical network with multiple coordinators or other access points, the coverage area of coordinators may overlap. Interference in the communication between coordinators and devices may occur in these overlapping coverage areas. Various embodiments propose an automatic allocation of reserved time slots to coordinators. These time slots support the coordinators to advertise their presence without interference and enable a device to detect the presence of a neighbour coordinator in a single MAC cycle. Cooperation of coordinators can be supervised by a global controller to determine non-interfering time schedules whereby the coordinators rely on interference reports from the devices in the overlapping coverage areas. Fast detection allows fast re-scheduling of time slots in the wireless optical network in order to prevent interference when a device that enters the overlapping coverage area of two coordinators.

Abstract: The power transmitter (101) providing power to a power receiver (105) comprises a communicator (309) communicating with the power receiver (105) and a negotiator (305) negotiating a guaranteed power level with the power receiver (105) prior to a power transfer phase. The guaranteed power level is a minimum power level guaranteed by the power transmitter (101) throughout the power transfer phase. During the power transfer phase, a determiner (307) dynamically determines an available power level based on the prevailing operating parameters. The available power level is one that can currently be provided but is not guaranteed. The power controller (309) is arranged to, during the power transfer phase, increase the power level above the guaranteed minimum level in response to power control messages, and to reduce the power level regardless of the power control messages in response to a detection that the power level exceeds the available power level.

Abstract: A wireless power transfer system comprises at least one power receiver (105) for receiving a power transfer from the power transmitter (101) via a wireless inductive power transfer signal. Configurers (207, 306) of the power transmitter and receiver may perform a configuration process to determine a set of power transfer parameter values which are used in a first power transfer. The power transfer parameter values and a first identity for the first power receiver (105) are stored. After a detection of an absence of the power receiver by a first controller (211), a detector (213) may detect a presence of a candidate power receiver. If the candidate power receiver is detected within a given duration and has an identity matching the first identity, an initialization processor (215) initializes a second power transfer using the set of stored parameter values. Otherwise it discards the set of stored parameter values.

Abstract: A wireless power transfer system comprises at least one power receiver (105) for receiving a power transfer from the power transmitter (101) via a wireless inductive power transfer signal. Configurers (207, 306) of the power transmitter and receiver may perform a configuration process to determine a set of power transfer parameter values which are used in a first power transfer. The power transfer parameter values and a first identity for the first power receiver (105) are stored. After a detection of an absence of the power receiver by a first controller (211), a detector (213) may detect a presence of a candidate power receiver. If the candidate power receiver is detected within a given duration and has an identity matching the first identity, an initialization processor (215) initializes a second power transfer using the set of stored parameter values. Otherwise it discards the set of stored parameter values.

Abstract: A wireless inductive power transfer system comprises a power transmitter for transmitting power inductively to a power receiver via transmitter coil 11 to receiver coil 21. In the system, a communication method comprises a step 37 of transmitting, by the power receiver, first data and second data to the power transmitter, the first data indicating a modulation requirement, and the second data indicating an inquiry message; a step 32 for receiving, by the power transmitter, the first data and the second data from the power receiver; a step 34 for transmitting, by the power transmitter, a response message for responding to said inquiry message, by modulating a power signal according to said modulation requirement so as to carry the response message; and a step 35 for receiving the response message by the power receiver by demodulating the modulated power signal carrying the response message received via the receiver coil from the power transmitter.

Abstract: A power transmitter (101) is arranged to transfer power to a power receiver (105) using a wireless inductive power signal. The power transmitter (101) comprises a power signal generator (207) which drives an inductor (103) to provide the power signal to an inductor of the power receiver (105). A power loop control is employed by the power receiver (105) providing power control error messages to the power transmitter (101). The power transmitter (101) comprises a query message processor (209) which can detect a query message received from the power receiver (105) using load modulation of the power signal. A modification processor (211) is arranged to modify a response of the power loop controller to the power control error messages dependent on the query message. The power receiver (105) can detect the modifications to the operation of the power control and thus can interpret this as a response to the query message.

Abstract: A power transmitter (501) for a wireless power transfer system includes a parallel resonance circuit (601) comprising at a transmitter coil (503) for generating the power transfer signal. A power source (605) has a current sink terminal and a power source terminal providing current to the parallel resonance circuit (601) with a limited rate of change of the current drawn. A first switch element (607) is coupled between a first end of the parallel resonance circuit (601) and the current sink terminal. A second switch element (609) is coupled between the other end and the current sink terminal. A driver (611) generates a cyclic drive signal such that each cycle comprises a two time intervals in which one switch element (607, 609) is closed and the other (607, 609) is open; and a third time interval in which both the first switch element (607) and the second switch element (609) are closed, the third time interval being between the other two intervals.

Abstract: An intermediate device for supporting a power transfer to an electromagnetic load (505) from a power transmitter (201) comprises a resonance circuit (507) including an inductor (801) and a capacitor (803) where the inductor (801) is arranged to couple to the power transmitter (201) through a first surface area (509) and to the electromagnetic load (505) through a second surface area (511). The resonance circuit (507) is arranged to 5 concentrate energy of the power transfer electromagnetic signal from the first surface area (509) towards the second surface area (511). The device further comprises a communicator (807) for exchanging messages with the power transmitter (201). The communicator (807) transmits a request message to the power transmitter (201) comprising a request for the power transmitter (201) to generate a measurement electromagnetic signal.

Abstract: A power transmitter (101) for a wireless power transfer system comprises a transmitter coil (103) and a driver (201) generates a drive signal for the transmitter coil (103) employing a repeating time frame with a power transfer time interval and a foreign object detection time interval. A test generator (211) generates a test drive signal for a test coil (209) during the foreign object detection time interval. A foreign object detector (207) performs a foreign object detection test based on a measured parameter for the test drive signal. Prior to entering a power transfer phase, an adapter (213) controls the power transmitter (101) to operate in a foreign object detection initialization mode in which a preferred value of a signal parameter for the test drive signal is determined in response to at least a first message received from the power receiver (105). During the foreign object detection time interval the signal parameter of is set to the preferred value.

Abstract: A wireless power transfer system comprises at least one power receiver (105) for receiving a power transfer from the power transmitter (101) via a wireless inductive power transfer signal. Configurers (207, 306) of the power transmitter and receiver may perform a configuration process to determine a set of power transfer parameter values which are used in a first power transfer. The power transfer parameter values and a first identity for the first power receiver (105) are stored. After a detection of an absence of the power receiver by a first controller (211), a detector (213) may detect a presence of a candidate power receiver. If the candidate power receiver is detected within a given duration and has an identity matching the first identity, an initialization processor (215) initializes a second power transfer using the set of stored parameter values. Otherwise it discards the set of stored parameter values.

Abstract: A power receiver receives a wireless power transfer from a power transfer signal generated by a wireless power transmitter during a power transfer phase. The power transfer signal employing a repeating time frame during the power transfer phase where the frame comprises at least a power transfer time interval and a foreign object detection time interval. The power receiver comprises a synchronizer (311) which synchronizes a local time reference to the repeating time frame and a load controller (309) which disconnects a load (303) during at least part of the foreign object time detection time intervals during at least part of the power transfer phase. The timing of the disconnecting is dependent on the local time reference. A mode controller (313) switches between a first operational mode and a second operational mode for the power transfer time intervals in response to a reliability measure for the synchronization.

Abstract: A wireless power transmitter capable of detecting a receiver and a method for the same is described. According to some implementations, the transmitter is configured to detect the presence of the receiver by detecting a change in capacitance in the transmitter by detecting the change in a current flowing through a capacitive circuit at the transmitter. According to some implementations, the capacitive circuit is formed by a first transmission coil corresponding to a first electrode and a second transmission coil corresponding to a second electrode. According to some implementations, the capacitive circuit is formed by a transmission coil as an electrode and a ground, or by the electrode and the receiver circuitry.

Abstract: A power transmitter (101) of a wireless power transfer system provides wireless power to a power receiver (105). The power transmitter (101) comprises a variable resonance circuit (201) generating an inductive power transfer signal in response to a drive signal. The resonance circuit comprises a capacitive and inductive impedance (201, 203), at least one of which is variable. The resonance frequency can be varied by at least one of the impedances being variable in response to a control signal. A driver (205) generates the drive signal with a variable drive frequency. A frequency modulator (305) applies frequency modulation to the drive signal by varying the variable drive frequency in response to data values to be transmitted to the power receiver (105). An adapter (309) generates the control signal in response to the data values such that the variable resonance frequency follows the variations in the drive frequency resulting from the frequency modulation of the drive signal.

Abstract: A power transmitter (101) for a wireless power transfer system comprises a transmitter coil (103) and a driver (201) generates a drive signal for the transmitter coil (103) employing a repeating time frame with a power transfer time interval and a foreign object detection time interval. A test generator (211) generates a test drive signal for a test coil (209) during the foreign object detection time interval. A foreign object detector (207) performs a foreign object detection test based on a measured parameter for the test drive signal. Prior to entering a power transfer phase, an adapter (213) controls the power transmitter (101) to operate in a foreign object detection initialization mode in which a preferred value of a signal parameter for the test drive signal is determined in response to at least a first message received from the power receiver (105). During the foreign object detection time interval the signal parameter of is set to the preferred value.

Abstract: In a LiFi network with multiple coordinators, interference in the overlapping areas between the local parts of the network can occur if each coordinator determines its own local time schedule for communicating with devices. To solve this problem, the invention proposes cooperation between the coordinators to determine non-interfering local time schedules whereby the coordinators rely on interference reports from the devices in the overlapping areas and apply a small number of simple rules. The proposed method is simple, scalable and independent from a central unit.