Abstract: A power transmitter (101) for wirelessly providing power to a power receiver (105) comprises a retriever (209) retrieving calibration data comprising a set of calibration parameters for each of a plurality of spatial positions of a calibration receiver relative to a calibration transmitter. A test generator (207) generates a test drive signal for a transmitter coil (103) to generate an electromagnetic test signal, and a test processor (213) determines a set of test parameters in response to the test drive signal. A position estimator (207) estimates a position of the power receiver relative to the power transmitter in response to a comparison of the test parameters to the calibration parameters for the plurality of spatial positions. The parameters include a power loss measure, a resonance frequency measure, and a coupling measure. The approach and specific parameters provide a substantially improved position estimation.

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: A power transmitter (101) for wirelessly providing power to a power receiver (105) comprises a retriever (209) retrieving calibration data comprising a set of calibration parameters for each of a plurality of spatial positions of a calibration receiver relative to a calibration transmitter. A test generator (207) generates a test drive signal for a transmitter coil (103) to generate an electromagnetic test signal, and a test processor (213) determines a set of test parameters in response to the test drive signal. A position estimator (207) estimates a position of the power receiver relative to the power transmitter in response to a comparison of the test parameters to the calibration parameters for the plurality of spatial positions. The parameters include a power loss measure, a resonance frequency measure, and a coupling measure. The approach and specific parameters provide a substantially improved position estimation.

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 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 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: An intermediate device for supporting a power transfer to an electromagnetic load (505) from a power transmitter (201) providing a power transfer electromagnetic signal comprises a resonance circuit (507) that includes a coil (701) and a capacitor (703). The coil (701) is arranged to electromagnetically couple to the power transmitter (201) and to the electromagnetic load (505) such that energy of the power transfer electromagnetic signal from the power transmitter (201) is concentrated towards the electromagnetic load (505). A hollow support structure (1001) has a laterally positioned air inlet (1205) and a centrally positioned air outlet (1207). The coil (701) is mounted on the hollow support structure (1001) and disposed around the central air outlet (1207). The device further comprises an air flow generator (901) for creating a flow of air into the air inlet (1205).

Abstract: A wireless power transfer system comprises a power transmitter (101) arranged to wirelessly power a power receiver (103) via an inductive signal. The power transmitter (101) comprises a variable resonance circuit for generating the inductive signal in response to a drive signal. The resonance circuit has a variable resonance frequency and comprises a transmitter coil (121) arranged to generate the inductive signal. A driver (707) generates the drive signal for the variable resonance circuit and a modulator (711) amplitude modulates the inductive signal by varying the variable resonance frequency in response to data values for transmission to the power receiver (105). The power receiver (105) comprises a demodulator (1105) for demodulating amplitude modulation of the inductive signal and a first power extractor (1113) for extracting power from the inductive signal and for powering at least part of the power receiver. The inductive signal may be provided in addition to a higher power main power transfer 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 reduced power time interval during which a power level of the power transfer signal is reduced. A driver (201) generates a drive signal for the transmitter coil (103) to generate the power transfer signal. A communicator (205) receives messages from the power receiver (105) and an adapter (213) adapts a timing property of the reduced power time interval in response to at least a first message received from the power receiver (105). A synchronizer (206) for synchronizing a foreign object detection and the generation of a test signal to occur during the reduced power time interval. The operation may typically be a foreign object detection or communication, and the timing property may e.g. be a duration of the reduced power time interval.

Abstract: A wireless power transfer system includes a power receiver (105) receiving a power transfer from a power transmitter (101) via a wireless inductive power transfer signal. The power transmitter (101) comprises a transmit power coil (103) generating the power transfer signal. A test signal coil (209) coupled to a test signal generator (211) generates a magnetic test signal. A plurality of spatially distributed detection coils (213) is coupled to measurement unit (215) generating a set of measurement values reflecting signals induced in the detection coils (213) by the magnetic test signal. A processor (217) determines a measurement spatial distribution of the measurement value where the spatial distribution reflects positions of the detection coils (213). A foreign object detector (219) detects a presence of a foreign object in response to a comparison of the measurement spatial distribution to a reference spatial distribution.

Abstract: A wireless power transmitter (101) comprises a driver (201) generating a drive signal for a transmitter coil (103) thereby generating a power transfer signal during power transfer intervals of a repeating time frame comprising at least one power transfer interval and one foreign object detection interval. A test generator (211) generates a test drive signal for a test coil (209) thereby generating an electromagnetic test signal during foreign object 5 detection intervals. A foreign object detector (207) performs a foreign object detection test in response to a measured parameter for the test drive signal during the foreign object detection intervals. An adapter (213) generates a varying test drive signal for the test coil (209) during an adaptation interval, and determines a test drive signal parameter value in response to the varying test 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: 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: A wireless power transfer system includes a power receiver and a power transmitter providing power using an inductive power signal. The power transmitter includes a resonance circuit having capacitive and inductive impedances, and a driver configured to generate a drive signal for the resonance circuit. A frequency modification circuit is configured to control the resonance frequency of the resonance circuit by slowing a state change for the capacitive and/or inductive impedance for a fractional time interval of at least some cycles of the drive signal, The frequency modification circuit is configured 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 is configured to generate the timing signal to have transitions synchronized to the drive signal. The slowing may be by impeding current flow between the capacitive and inductive impedances.

Abstract: A power transmitter (2) for transferring power to a power receiver comprises a first inductor (307) for providing power and a second inductor (407) for receiving data signals from a power receiver. The first (307) and second (407) inductors are separate inductors in a power transfer circuit (701) and a data signal receiving circuit (702). The data signal receiving circuit (702) comprises a data extracting circuit (1007) for extracting the data signals received by the second inductor (407). The power transmitter comprises a control circuit (401) for controlling the power in dependence on the data signals. The power transmitter transfers power during power transfer periods and receives data during communication periods, communication periods corresponding to periods wherein power is low.

Abstract: A wireless power transfer system includes a power transmitter (101) arranged to provide a power transfer to a power receiver (105) via a wireless inductive power transfer signal where the power transfer signal is provided in a power time interval of a repeating power transfer signal time frame. The time frame furthermore comprises a reduced power time interval. An apparatus (typically being the power receiver (105) or the power transmitter (101)) comprises a short range communication unit (305, 405) arranged to communicate data messages with a second entity (which is the complementary unit, i.e. either the power transmitter (101)) or the power receiver (105)) using short range communication. The short range communication has a range not exceeding 20 cm. The apparatus further comprises a synchronization unit (309, 409) arranged to synchronize the short range communication to the power transfer signal time frame such that short range communication is restricted to the reduced power time intervals.

Abstract: A wireless power transfer system comprises a power transmitter (101) arranged to wirelessly power a power receiver (103) via an inductive signal. The power transmitter (101) comprises a variable resonance circuit for generating the inductive signal in response to a drive signal. The resonance circuit has a variable resonance frequency and comprises a transmitter coil (121) arranged to generate the inductive signal. A driver (707) generates the drive signal for the variable resonance circuit and a modulator (711) amplitude modulates the inductive signal by varying the variable resonance frequency in response to data values for transmission to the power receiver (105). The power receiver (105) comprises a demodulator (1105) for demodulating amplitude modulation of the inductive signal and a first power extractor (1113) for extracting power from the inductive signal and for powering at least part of the power receiver. The inductive signal may be provided in addition to a higher power main power transfer 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: 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 power transmitter for transferring power to a power receiver using a wireless inductive power signal includes a power source provides a power source signal which may have level variations. A power signal generator generates a drive signal from the power source signal by a frequency converter which increases the frequency of the drive signal relative to the power source signal. A limiter restricts the power of the drive signal fed to the inductor to be below a threshold in repeating time intervals. A synchronizer synchronizes the repeating time intervals to the power source signal. In the power receiver, an inductor receives a power signal from the power transmitter, a load coupler decouples the power load from the inductor during the repeating time intervals and a synchronizer synchronizes the repeating time intervals of the receiver to the power signal. Communication units exchange data during the repeating time intervals.