Abstract: A power receiving device is disposed underwater. The power receiving device includes a housing formed of a weak magnetic material, a ferromagnetic body that surrounds an outer side of the housing and is formed of a ferromagnetic material, and a power receiving coil wound around an outer side of the ferromagnetic body.

Abstract: A power transmission coil includes a plurality of coil members each of which having a length capable of surrounding at least one power reception device located under water from all directions and that are configured to wirelessly transmit power to the power reception device. Each of the plurality of coil members includes a polygonal pipe having a polygonal shape in which a plurality of straight pipes are welded, and a conductive wire that is inserted into the polygonal pipe and is wound a plurality of times.

Abstract: A power transmitting device transmits power to a power receiving device having a power receiving coil in water. The power transmitting device includes a power transmitting coil configured to transmit the power to the power receiving coil via a magnetic field. The power transmitting device also includes a support member that supports the power transmitting coil, and one or more spacers that hold the transmitting coil and the support member.

Abstract: A power receiving device is disposed underwater. The power receiving device includes a housing formed of a weak magnetic material, a ferromagnetic body that surrounds an outer side of the housing and is formed of a ferromagnetic material, and a power receiving coil wound around an outer side of the ferromagnetic body.

Abstract: An electric power transmission device transmits electric power to an electric power reception device including an electric power reception coil in water. The electric power transmission device includes one or more transmission coils which include an electric power transmission coil configured to transmit electric power to the electric power reception coil via a magnetic field, an electric power transmitter, configured to transmit AC power to the electric power transmission coil, a capacitor which is connected to the transmission coil and forms a resonance circuit which resonates with the transmission coil, a first tubular member which is waterproof and seals a periphery of the transmission coil, a second tubular member which surrounds the first tubular member and includes a plurality of holes, and an adjuster, configured to adjust an amount of air in a gap between the first tubular member and the second tubular member.

Abstract: An underwater communication device is provided and adapted to communicate data in water with another underwater communication device including another coil. The underwater communication device includes a first coil configured to transmit data to and from the other coil via a magnetic field, a second coil configured to transmit the data to and from the other coil via a magnetic field, and a supply unit configured to supply the data to at least one of the first coil and the second coil. A coil surface of the first coil and a coil surface of the second coil overlap each other.

Abstract: A power transmitting device transmits power to a power receiving device having a power receiving coil in water. The power transmitting device includes a power transmitting coil configured to transmit the power to the power receiving coil via a magnetic field. The power transmitting device also includes a support member that supports the power transmitting coil, and one or more spacers that hold the transmitting coil and the support member.

Abstract: A power transmitting device transmits power to a power receiving device having a power receiving coil, in water. The power transmitting device includes one or more annular transmitting coils including a power transmitting coil configured to transmit the power to the power receiving coil via a magnetic field, a support member located in an inner space of the transmitting coil, which is formed by the annular transmitting coil, the support member including an outer periphery along an inner periphery of the annular transmitting coil, and supporting the transmitting coil from the inner space, a power transmitting unit configured to supply A/C power to the power transmitting coil, and a capacitor connected to the transmitting coil, and forming a resonance circuit resonating together with the transmitting coil.

Abstract: A transmission coil configured to transmit electric power in water includes an annular electric wire through which an alternating current flows, and a first cover which includes non-conductive resin or non-magnetic resin and seals a periphery of the electric wire. The electric wire transmits the electric power via a magnetic field generated by flowing of the alternating current. The first cover includes a second cover which surrounds an outer peripheral surface of the electric wire in a radial direction with the non-conductive resin or the non-magnetic resin, and a self-bonding tape configured to seal an outer peripheral surface of the second cover.

Abstract: A underwater communication device communicates data with another underwater communication device having another first coil and another second coil in water. The underwater communication device includes a first coil configured to transmit the data to and from the other first coil via a magnetic field, a second coil configured to transmit the data to and from the other second coil via a magnetic field, a supply unit configured to supply the data to the first coil and the second coil, a first capacitor connected to the first coil and forming a first resonance circuit that resonates with the first coil at a first resonance frequency, and a second capacitor connected to the second coil and forming a second resonance circuit that resonates with the second coil at a second resonance frequency that is different from the first resonance frequency.

Abstract: Provided is a transmission coil which can inhibit reduction in transmission efficiency during underwater non-contact electric power transmission. A transmission coil configured to transmit electric power in water includes an annular electric wire through which an alternating current flows, and a first cover which includes non-conductive resin or non-magnetic resin and seals a periphery of the electric wire. The electric wire transmits the electric power via a magnetic field generated by flowing of the alternating current.

Abstract: A underwater communication device communicates data with another underwater communication device having another first coil and another second coil in water. The underwater communication device includes a first coil configured to transmit the data to and from the other first coil via a magnetic field, a second coil configured to transmit the data to and from the other second coil via a magnetic field, a supply unit configured to supply the data to the first coil and the second coil, a first capacitor connected to the first coil and forming a first resonance circuit that resonates with the first coil at a first resonance frequency, and a second capacitor connected to the second coil and forming a second resonance circuit that resonates with the second coil at a second resonance frequency that is different from the first resonance frequency.

Abstract: An electric power transmission device capable of efficiently performing contactless electric power transmission to an underwater vehicle in water is provided. The electric power transmission device, which is an electric power transmission device transmitting electric power to an electric power reception device including an electric power reception coil in water, includes one or more transmission coils including an electric power transmission coil which transmits electric power to an electric power reception coil via a magnetic field, an electric power transmission unit which transmits AC power to an electric power transmission coil, a capacitor which is connected to the transmission coil and forms a resonant circuit which resonates with the transmission coil, and a buoyant body connected to at least one of the transmission coils.

Abstract: Provided is a transmission coil which can inhibit reduction in transmission efficiency during underwater non-contact electric power transmission. A transmission coil configured to transmit electric power in water includes an annular electric wire through which an alternating current flows, and a first cover which includes non-conductive resin or non-magnetic resin and seals a periphery of the electric wire. The electric wire transmits the electric power via a magnetic field generated by flowing of the alternating current.

Abstract: An electric power transmission device transmits electric power to an electric power reception device including an electric power reception coil in water. The electric power transmission device includes one or more transmission coils which include an electric power transmission coil configured to transmit electric power to the electric power reception coil via a magnetic field, an electric power transmitter, configured to transmit AC power to the electric power transmission coil, a capacitor which is connected to the transmission coil and forms a resonance circuit which resonates with the transmission coil, a first tubular member which is waterproof and seals a periphery of the transmission coil, a second tubular member which surrounds the first tubular member and includes a plurality of holes, and an adjuster, configured to adjust an amount of air in a gap between the first tubular member and the second tubular member.

Abstract: A power transmission device transmits power underwater to a power reception device including a power reception coil. The power transmission device includes: a power transmission coil that transmits power to the power reception coil through a magnetic field; a power transmitter that transmits an alternating current power having a predetermined frequency to the power transmission coil; and a first capacitor that is connected to the power transmission coil and forms a resonance circuit resonating with the power transmission coil. The predetermined frequency is a frequency between a first frequency at which a geometric mean value of a Q value of the power transmission coil and a Q value of the power reception coil are the maximum and a second frequency at which the Q value of the power transmission coil and the Q value of the power reception coil are the same.

Abstract: A power transmitting device transmits power tower power receiving device having a power receiving coil, in water. The power transmitting device includes one or more annular transmitting coils including a power transmitting coil configured to transmit the power to the power receiving coil via a magnetic field, a support member located in an inner space of the transmitting coil, which is formed by the annular transmitting coil, the support member including an outer periphery along an inner periphery of the annular transmitting coil, and supporting the transmitting coil from the inner space, a power transmitting unit configured to supply A/C power to the power transmitting coil, and a capacitor connected to the transmitting coil, and forming a resonance circuit resonating together with the transmitting coil.

Abstract: A power transmission device is configured to transmit power underwater to an underwater vehicle having a power reception coil. The power transmission device includes a power transmission coil configured to transmit power to the power reception coil through a magnetic field, a power transmission unit configured to transmit an alternating current voltage having a frequency a 10 kHz or lower to the power transmission coil, and a first capacitor connected to the power transmission coil and configured to form a resonance circuit resonating at the frequency with the power transmission coil.

Abstract: An electric power transmission device capable of efficiently performing contactless electric power transmission to an underwater vehicle in water is provided. The electric power transmission device, which is an electric power transmission device transmitting electric power to an electric power reception device including an electric power reception coil in water, includes one or more transmission coils including an electric power transmission coil which transmits electric power to an electric power reception coil via a magnetic field, an electric power transmission unit which transmits AC power to an electric power transmission coil, a capacitor which is connected to the transmission coil and forms a resonant circuit which resonates with the transmission coil, and a buoyant body connected to at least one of the transmission coils.

Abstract: A power transmission device transmits power underwater to a power reception device including a power reception coil. The power transmission device includes: a power transmission coil that transmits power to the power reception coil through a magnetic field; a power transmitter that transmits an alternating current power having a predetermined frequency to the power transmission coil; and a first capacitor that is connected to the power transmission coil and forms a resonance circuit resonating with the power transmission coil. The predetermined frequency is a frequency between a first frequency at which a geometric mean value of a Q value of the power transmission coil and a Q value of the power reception coil are the maximum and a second frequency at which the Q value of the power transmission coil and the Q value of the power reception coil are the same.