Abstract: A contactless power feeding system comprises a power feeding device and a movable device. The movable device is installed on a power feeding case of the power feeding device, and a liquid crystal TV (E) is installed on the movable device. The liquid crystal TV (E) can be arranged at a desired position on a wall (W) in a room (R) by moving the movable device along the power feeding case. The liquid crystal TV (E) can be arranged at a desired height by moving the liquid crystal TV (E) in the axial direction of a guide pipe provided on a power receiving case. The liquid crystal TV (E) can be directed in a desired direction by rotating the liquid crystal TV (E) around the guide pipe. The contactless power feeding system feeds power to the liquid crystal TV (E) via the power feeding device and the movable device.

Abstract: A wireless power transmission device includes a detection coil and a capacitor that configure a resonance circuit. An oscillation circuit generates high-frequency current corresponding to a detection frequency for performing presence detection of an electric appliance and metal. A presence detection circuit performs presence detection of the electric appliance and the metal based on an output voltage obtained by exciting the detection coil with the high-frequency current having the detection frequency. A detection condition changing circuit performs an initial value setting mode that changes a detection condition of the presence detection circuit in accordance with a resonance characteristic. The detection condition changing circuit includes a detection frequency changing circuit that changes the detection frequency in accordance with the resonance characteristic.

Abstract: A power feeding device includes: a series circuit including a primary coil and a capacitor connected in series with each other; a switching circuit and a control circuit. The power feeding device is configured to supply power from the primary coil to a secondary coil of a power receiving device in a non-contact manner. The switching circuit is configured to alternate a direction of a voltage between both ends of the series circuit. The control circuit is configured to control a frequency by which the switching circuit performs alternating operation for alternating the direction of the voltage. The control circuit is configured to: measure a voltage at a connection point between the primary coil and the capacitor; and determine, based on a phase of the voltage, whether current flowing through the primary coil is in a phase advance state or a phase delay state.

Abstract: A wireless power transmission device includes a detection coil and a capacitor that configure a resonance circuit. An oscillation circuit generates high-frequency current corresponding to a detection frequency for performing presence detection of an electric appliance and metal. A presence detection circuit performs presence detection of the electric appliance and the metal based on an output voltage obtained by exciting the detection coil with the high-frequency current having the detection frequency. A detection condition changing circuit performs an initial value setting mode that changes a detection condition of the presence detection circuit in accordance with a resonance characteristic. The detection condition changing circuit includes a detection frequency changing circuit that changes the detection frequency in accordance with the resonance characteristic.

Abstract: A contactless power feeding system comprises a power feeding device and a movable device. The movable device is installed on a power feeding case of the power feeding device, and a liquid crystal TV (E) is installed on the movable device. The liquid crystal TV (E) can be arranged at a desired position on a wall (W) in a room (R) by moving the movable device along the power feeding case. The liquid crystal TV (E) can be arranged at a desired height by moving the liquid crystal TV (E) in the axial direction of a guide pipe provided on a power receiving case. The liquid crystal TV (E) can be directed in a desired direction by rotating the liquid crystal TV (E) around the guide pipe. The contactless power feeding system feeds power to the liquid crystal TV (E) via the power feeding device and the movable device.

Abstract: The energy harvesting device includes a power management circuit to charge a storage with power from a generator including generation units to generate AC power when vibrated. The power management circuit includes: a first power extraction circuit including a rectification circuit converting AC power at a first input unit into DC power; a second power extraction circuit including a switching circuit operating with power from the storage and generating DC power using AC power at a second input unit; and a switch circuit having a first connection mode of connecting the first input unit to the generation units to receive an AC voltage greater in effective value than an AC voltage to the second input unit, and a second connection mode of connecting the second input unit to the generation units to receive an AC voltage greater in effective value than an AC voltage to the first input unit.