Abstract: A power receiving device and a wireless power transfer system including the same for non-contact power transfer to a plurality of mobile bodies are obtained, which allow stable power transfer even when the number of power transfer targets varies. In the wireless power transfer system, electric power is transmitted from a power transmitting source in a power transmitting device to generate a high frequency voltage and a power-transmitting resonant circuit with a power transmitting coil to generate an AC magnetic flux by resonance when receiving the high frequency voltage. A power-receiving resonant circuit receives the AC magnetic flux transmitted from the power-transmitting resonant circuit and converts the AC magnetic flux into AC power. At least one compensation element cancels out a variation of an inductance of the power transmitting coil attributable to the movement of the power-receiving resonant circuit to a position where electric power can be received.

Abstract: A wireless power feeding system includes: a power transmission circuit portion for converting DC power supplied from a main power supply, to AC power, and for supplying the AC power to a power-transmission-side coil; input power control means for controlling the AC power to be supplied to the power-transmission-side coil; a power-reception-side coil which is magnetically coupled with the power-transmission-side coil and to which AC power is transmitted from the power-transmission-side coil through magnetic energy accumulated between the power-reception-side coil and the power-transmission-side coil; a power reception circuit including a rectifier for converting the AC power transmitted to the power-reception-side coil, to DC, and a power-reception-side DC/DC converter; and power reception circuit control means for controlling rectifier output voltage to be a maximum efficiency voltage at which power transmission efficiency becomes maximum.

Abstract: An elevator includes: a car moving in a hoistway; a load provided to the car; a first power storage unit, composed of one battery capable of charging and discharging, connected to the load, and supplying power to the load; a second power storage unit, composed of one or more batteries capable of charging and discharging, and connected to the load; a power transmission circuit and capable of transmitting power between the first power storage unit and the second power storage unit; and a control unit controlling the power transmission circuit to supply power from the second power storage unit to the first power storage unit, when it is determined that a remaining stored power amount of the battery constituting the first power storage unit is less than an amount of power required for driving the load for a certain period of time.

Abstract: A power receiving device of a wireless power transfer system receives power from a power transmitting circuit connected to a power source and having a power transmitting coil. The power receiving device includes a power receiving circuit, a power converter, an LC filter, and switches which are controlled by a control device on the basis of voltage detected by voltage detection means for detecting output voltage of the power receiving circuit, so that conduction between the power receiving circuit and the power converter is interrupted during a non-power-transfer period.

Abstract: A wireless power supply system for elevators includes a power transmitting device, first and second power receiving devices provided in the first and second elevator cars respectively, and a control device. The power transmitting device includes power transmitting units each having an inverter and two power transmitter coils. The first power receiving device includes first power receiving units each having a rectifier circuit and a power receiver coil that can be coupled with one of the two power transmitter coils. The second power receiving device includes second power receiving units each having a rectifier circuit and a power receiver coil that can be coupled with the other of the two power transmitter coils. The power transmitting device, or the first and second power receiving devices include switches to disconnect the inverter and the first load device as well as the inverter and the second load device.

Abstract: An elevator includes a plurality of power transmission/reception devices each including: a power transmission coil connected to a main power supply; a power reception coil for receiving power transmitted from the power transmission coil and supplying power to a load; and an inverter which is provided between the main power supply and the power transmission coil, and which converts power supplied from the main power supply, to power having a predetermined frequency, and supplies the power to the power transmission coil, wherein the plurality of power transmission/reception devices are connected in parallel between the main power supply and the load. Since the inverters are individually connected to the power transmission coils, it is possible to efficiently supply power to the load even when using some of the power transmission coils.

Abstract: A wireless power feeding system includes: a power transmission circuit portion for converting DC power supplied from a main power supply, to AC power, and for supplying the AC power to a power-transmission-side coil; input power control means for controlling the AC power to be supplied to the power-transmission-side coil; a power-reception-side coil which is magnetically coupled with the power-transmission-side coil and to which AC power is transmitted from the power-transmission-side coil through magnetic energy accumulated between the power-reception-side coil and the power-transmission-side coil; a power reception circuit including a rectifier for converting the AC power transmitted to the power-reception-side coil, to DC, and a power-reception-side DC/DC converter; and power reception circuit control means for controlling rectifier output voltage to be a maximum efficiency voltage at which power transmission efficiency becomes maximum.

Abstract: A parallel power supply device according to the present invention includes: a plurality of DC/DC converters connected in parallel to perform power conversion between a DC power supply and a common load; a voltage detector to detect a voltage of the common load; and a plurality of control circuits each to control a corresponding one of the plurality of DC/DC converters, wherein during parallel operation of the plurality of DC/DC converters, the plurality of control circuits control the plurality of DC/DC converters by proportional control using a same target voltage value and a same proportional gain, based on a voltage value of the common load detected by the voltage detector. Therefore, in the parallel power supply device in which the plurality of DC/DC converters are connected in parallel, the individual DC/DC converters can supply electric power to the load independently and equally.

Abstract: The present application provides a resin-molded capacitor such that heat generated by a capacitor element can be efficiently dissipated, and a power conversion device. The resin-molded capacitor includes a first bus bar and a second bus bar joined to a first capacitor electrode and a second capacitor electrode respectively of a capacitor element, an insulating member joined to at least one of the first capacitor electrode and the second capacitor electrode or at least one of the first bus bar and the second bus bar, and an electrically conductive member joined to the insulating member.

Abstract: A parallel power supply device according to the present invention includes: a plurality of DC/DC converters connected in parallel to perform power conversion between a DC power supply and a common load; a voltage detector to detect a voltage of the common load; and a plurality of control circuits each to control a corresponding one of the plurality of DC/DC converters, wherein during parallel operation of the plurality of DC/DC converters, the plurality of control circuits control the plurality of DC/DC converters by proportional control using a same target voltage value and a same proportional gain, based on a voltage value of the common load detected by the voltage detector. Therefore, in the parallel power supply device in which the plurality of DC/DC converters are connected in parallel, the individual DC/DC converters can supply electric power to the load independently and equally.

Abstract: The present application provides a resin-molded capacitor such that heat generated by a capacitor element can be efficiently dissipated, and a power conversion device. The resin-molded capacitor includes a first bus bar and a second bus bar joined to a first capacitor electrode and a second capacitor electrode respectively of a capacitor element, an insulating member joined to at least one of the first capacitor electrode and the second capacitor electrode or at least one of the first bus bar and the second bus bar, and an electrically conductive member joined to the insulating member.