Abstract: A wireless power transmission system and a method for increasing a coupling efficiency by adjusting a resonant frequency are provided. A device of the wireless power transmission system includes a resonator configured to transmit a wireless power, and a communication unit configured to receive information from another device. The device further includes a controller configured to determine a power transmission efficiency based on the information, and adjust a resonant frequency of the device, a resonant frequency of a relay device, and a resonant frequency of the other device, if the power transmission efficiency is less than or equal to a predetermined reference efficiency.

Abstract: A wireless power transmission system with an enhanced magnetic field strength is provided. A wireless power transmitter includes a generator configured to generate a power. The wireless power transmitter further includes a resonator configured to generate a magnetic field to transmit the power to a target device. The wireless power transmitter further includes a slab unit configured to enhance the magnetic field.

Abstract: A wireless power transmission system based on cell division is provided. A communication and power control method of the wireless power transmission system, includes setting a magnetic coupling zone. The method further includes detecting a target device in the magnetic coupling zone. The method further includes transmitting a power to the target device. The method further includes adjusting an amount of the power based on a transmission efficiency of the power.

Abstract: A wireless power transmission system and a multi-mode resonator in the wireless power transmission system are provided. The multi-mode resonator includes a transmission line portion including unit-cells, the unit-cells including respective ends connected to each other, and each of the unit-cells including a capacitor, an inductor connected in parallel to the capacitor, and a via. The multi-mode resonator further includes a ground conducting portion configured to provide an electrical ground to the transmission line portion through the via of each of the unit-cells.

Abstract: A wireless power transmission system, and a method of controlling power in the wireless power transmission system based on a detection parameter are provided. The method includes transmitting a request signal to a device. The method further includes receiving, from the device, a response signal corresponding to the request signal, the response signal including a parameter of the device. The method further includes generating an operation power based on the parameter of the device, the operation power being used for an operation of the device.

Abstract: A method and apparatus for data communication in wireless power transmission are provided. A wireless power transmitter includes a resonance antenna configured to wirelessly transmit a power to a wireless power receiver, and receive a signal from the wireless power receiver, the signal including a sub-carrier. The wireless power transmitter further includes a controller configured to receive the signal from the resonance antenna, and receive data from the wireless power receiver based on the sub-carrier.

Abstract: A wireless power transmission system and a method based on an impedance matching condition are provided. A source device of the wireless power transmission system, includes a power converter configured to generate power. The source device further includes a resonator configured to transmit the power to a target device. A ratio of an input impedance of the resonator to an output impedance of the power converter is less than a reference value.

Abstract: A wireless power transmission system, a resonator in the wireless power transmission system, and a resonator design method for optimum power division are provided. A power receiver of the wireless power transmission system, includes a resonator configured to receive a power from a power transmitter. The power receiver further includes a power supply configured to supply the received power to a load. A figure of merit (FOM) of the resonator corresponds to a power dividing ratio of the power transmitter.

Abstract: A sound system using wireless power transmission is provided. A power and data transmission apparatus in the sound system, includes a data transmitting unit configured to wirelessly transmit, to a sound output device, sound data. The apparatus further includes a power transmitting unit configured to wirelessly transmit, to the sound output device, power. The apparatus further includes a controller configured to control the data transmitting unit and the power transmitting unit based on a distance between the apparatus and the sound output device.

Abstract: A source device and a method for controlling a magnetic field using two source resonators in a wireless power transmission system are provided. A device configured to control a magnetic field, includes resonators configured to form the magnetic field to transmit power to another device. The device further includes a magnetic field shape determining unit configured to determine a shape of the magnetic field. The device further includes a phase changing unit configured to change a phase of at least one of the resonators to form the magnetic field in the determined shape.

Abstract: An apparatus and method are described that may enable a target device to communicate with a source device using a wireless power. The communication apparatus receives a wireless power from a source resonator through a magnetic coupling between the source resonator and a target resonator. The communication apparatus transmits a message, and modulates the message based on the received wireless power and impedance mismatch between the source device and the target device. The communication apparatus controls the impedance mismatch by changing an impedance of the target device.

Abstract: A method and apparatus to detect load fluctuation of a wireless power transmission are provided. A wireless power transmitter includes a resonator configured to wirelessly transmit, to a target device, an output power. The wireless power transmitter further includes a power detector configured to detect a current of the output power. The wireless power transmitter further includes a controller configured to detect a change in the current, and to detect a target load based on the change in the current. The target load includes a load of which the output power is applied thereto.

Abstract: Provided are methods and apparatuses for distributing wireless power in a wireless power transmission system. According to a general aspect, a source device that distributes a wireless power in a wireless power transmission system may include: a matching circuit searching unit configured to determine information associated with a matching circuit of a source device based on one or more target devices and the amount of power to be distributed to the one or more of the target devices; and a matching circuit modifying unit configured to modify the shape of the matching circuit of the source device to correspond to the determined information associated with the matching circuit of the source device.

Abstract: An apparatus and method for communication using a wireless power are provided. The apparatus includes an amplifier configured to amplify an input signal based on a power supplied to the amplifier. The apparatus further includes a control unit configured to detect a change in an impedance of a target device, and to change the power based on the change in the impedance. The apparatus further includes a demodulation unit configured to receive a message from the target device, and to demodulate the message based on the changed power.

Abstract: A wireless power transmission and charging system, and a power control method of the wireless power transmission and charging system are provided. The power control method may include generating charging power using the power amplifier. The charging power may be used to charge a target device. The charging power may be transmitted to the target device. The voltage supplied to the power amplifier may be adjusted based on a detected change in the current input to the power amplifier, a detected change in the temperature of the source device, a detected change in the amount of the power received to the target device, or a detected change in the temperature of the target device.

Abstract: An electronic device and method for transmitting and receiving a wireless power are provided. An electronic device for transmitting and receiving wireless power may include a resonator configured to operate, based on a plurality of operating modes of the electronic device including a power reception mode, a relay mode, and a power transmission mode, wherein: (i) in the power reception mode, the resonator is configured to receive power from a wireless power transmitter, (ii) in the relay mode, the resonator is configured to relay power received from the wireless power transmitter to a wireless power receiver, and (iii) in the power transmission mode, the resonator is configured to transmit power to the wireless power receiver; and a path controller configured to control at least one electrical pathway of electronic device based on the operating mode.

Abstract: An apparatus for transmitting a high efficiency variable power includes a pulse generating unit configured to generate a pulse signal comprising a pulse having a duration corresponding to an amount of power transmitted; a pulse stream generating unit configured to convert the pulse signal to a pulse stream having pulse shape corresponding to the duration of the pulse and data to be transmitted; and a high frequency modulating unit configured to output a variable power by modulating a high frequency signal having a constant amplitude on a time axis by repeatedly outputting and not outputting the high frequency signal based on the pulse stream.

Abstract: An apparatus and method of protecting a power receiver of a wireless power transmission system are provided. A wireless power receiver includes a rectifier comprising an input and an output, and configured to receive a signal through the input, to rectify the signal to produce a rectified signal, and to output the rectified signal through the output, and a capacitor connected to the output of the rectifier and to ground. The wireless power receiver further includes a direct current-to-direct current (DC/DC) converter connected to the output of the rectifier and to a load, and configured to convert the rectified signal to a power, and to provide the power to the load, and a device configured to create a short circuit to protect the rectifier and/or the capacitor when a voltage greater than a threshold voltage is applied to the input of the rectifier and/or the output of the rectifier.

Abstract: A rectifier is provided. The rectifier includes a first rectification unit having an anode connecting to a negative radio frequency (RF) port and a cathode connecting to a positive direct current (DC) port, a second rectification unit having an anode connecting to a positive RF port and a cathode connecting to the positive DC port, a third rectification unit having an anode connecting to a ground and a cathode connecting to the negative RF port, and a fourth rectification unit having an anode connecting to the ground and a cathode connecting to the positive RF port. The first rectification unit includes a plurality of first diodes that are connected in parallel, and the second rectification unit includes a plurality of second diodes that are connected in parallel.

Abstract: An apparatus and method of using near field communication (NFC) and wireless power transmission (WPT) are provided. A power receiving apparatus includes a resonator configured to receive a power and to output the power. The power receiving apparatus further includes a near field communication (NFC) receiver configured to perform wireless communication using the power output by the resonator. The power receiving apparatus further includes a wireless power transmission (WPT) receiver configured to supply a voltage using the power output by the resonator. The power receiving apparatus further includes a connecting unit configured to selectively connect the resonator to either the NFC receiver or the WPT receiver. The power receiving apparatus further includes a mode selector configured to control the connecting unit to selectively connect the resonator to either the NFC receiver or the WPT receiver based on the power output by the resonator.