Murata Manufacturing Co., Ltd.

Murata Mfg. Co., Ltd.

Murana Mfg. Co. Ltd.

Tsuyoshi Suesada

Teruhisa Tsuru

Seiji Kanba

Keiichi Ichikawa

Kenji Asakura

Harufumi Mandai

Henri Bondar

Hironobu Takahashi

Yujiro Dakeya

Hiromi Murayama

Shinji Goma

Makoto Yasutake

Kentaro Mikawa

Kazuaki Higashibata

Kengo Matsumoto

Sinji Goma

Toshihiro Hosokawa

Noboru Kato

Nobuhito Tsubaki

Kazuya Kato

Kunihiro Watanabe

Masaki Kawata

Akihiko Shibata

Hironori Sakai

Seiji Kanaba

Yujiro Dakeyo

Yosuke Kawanami

Sejii Kanaba

A wireless IC tag-attached metal medical instrument includes a metal medical instrument including a metal portion. The metal medical instrument is configured such that electric, magnetic, or electromagnetic field coupling is established between a resonant circuit and the metal portion when a wireless IC tag is fixed to the metal portion that includes the resonant circuit having an inductor with a spiral or helix shape that turns around a central axis more than one turn. In this configuration, the metal portion either emits a transmission signal with a frequency equal to a resonant frequency of an electromagnetic wave supplied from the resonant circuit or receives a reception signal having a frequency equal to the resonant frequency, and supplies the reception signal to the resonant circuit.

Wireless IC tag-attached metal medical instrument

A medical instrument is provided in which a wireless IC tag is fixed to a first or second body, such that at least part of the wireless IC tag is positioned more frontward than a front end of a first ring and a front end of a second ring and more backward than a support. A winding axis of an inductor is orthogonal to the up-down direction and intersects the front-back direction so that electric, magnetic, or electromagnetic field coupling is established between a resonant circuit and a metal medical instrument. Moreover, the metal medical instrument either emits a transmission signal, which has a frequency equal to a predetermined resonant frequency and supplied from the resonant circuit, as an electromagnetic wave, or it receives a reception signal having a frequency equal to the predetermined resonant frequency as an electromagnetic wave, and supplies the reception signal to the resonant circuit.

A first power transfer circuit in a first power transfer apparatus and a second power transfer circuit in a second power transfer apparatus are configured to be electrically symmetrical to each other. In transfer of electric power from one of the first and second power transfer apparatuses to the other of the first and second power transfer apparatuses, a controller drives a first switching circuit and a second switching circuit using a parallel resonant frequency of a complex resonant circuit as a reference frequency of an operating frequency. The controller changes the operating frequency to a frequency higher than the reference frequency or a frequency lower than the reference frequency if a duty ratio is maximized when transmitted electric power is lower than target electric power, which is a control target value, during the driving at the reference frequency.

Bidirectional wireless power transmission system

A voltage detection circuit includes an inductor connected to connection portions configured to input an alternating-current voltage, an inductor magnetic-field coupled to the inductor, a capacitor connected in parallel to the inductor and constituting a secondary-side resonant circuit with the inductor, and a voltage detector configured to detect an output voltage from the secondary-side resonant circuit. Therefore, a voltage detection circuit, a power transmission device, and a power transmission system capable of detecting an alternating-current voltage with high detection sensitivity irrespective of the potential of a power transmission line are provided.

Voltage detection circuit, power transmission device, and power transmission system

An antenna device includes a first coil antenna conductor including first and second ends, a second coil antenna conductor including third and fourth ends, and a switching circuit. The first coil antenna conductor is wound around an axis and the second coil antenna conductor is wound around an axis. The switching circuit switches a connection state of the first coil antenna conductor and the second coil antenna conductor between connection states including series connection and parallel connection.

Antenna device and electronic apparatus

An inductor module includes a laminate where multiple insulator layers are laminated, a main line conductor in the shape of a straight line formed on the laminate, a current detection conductor that is formed on the laminate and magnetically coupled with the main line conductor, and coil conductors that are formed on the laminate and constitute an inductor element. An absolute value of a coupling coefficient between the main line conductor and inductor element, and an absolute value of a coupling coefficient between the current detection conductor and the inductor element, are each smaller than an absolute value of a coupling coefficient between the main line conductor and the current detection conductor. Thus, an inductor module that detects current and is used as an inductor element, and an electric power transmission system including the inductor module, are provided.

Inductor module and electric power transmission system

A power transfer system that transfers electric power from a power transmission device to a power reception device through electrical coupling. The power transmission device and the power reception device structurally designed such that the power transfer system is able to stabilize reference potentials of the power transmission device and the power reception device when the power reception device is placed on the power transmission device.

Power transfer system with capacitive coupling

A power transmission system is disclosed in which power is transmitted from a power transmission apparatus to a power receiving apparatus by electric field coupling between active and passive electrodes. The power transmission apparatus includes a step-up/down circuit for stepping up or down a direct voltage and an inverter circuit for converting the direct voltage into an alternating voltage that is output to the active and passive electrodes. The power transmission apparatus controls the step-up/down circuit to sweep a transformation ratio M=Vo/Vin and detects the ratio M when an input power Pin of the step-up/down circuit is a minimum. The power transmission apparatus drives the step-up/down circuit to obtain the ratio M and perform the power transmission. As a result, there is provided a power transmission system capable of efficiently performing power transmission regardless of the change in a load in the power receiving apparatus.

Power transmission system

A capacitance (Cp) is a capacitance formed between a transmitting-device-side passive electrode and a receiving-device-side passive electrode. A capacitance (Ca) is a capacitance formed between a transmitting-device-side active electrode and a receiving-device-side active electrode. A bridge circuit formed by Zto Zis connected to a secondary side of a step-up transformer, where Zrepresents an impedance of a first element, Zrepresents an impedance of a second element, Zrepresents an impedance of a series circuit formed by the capacitance (Ca) and a load, and Zrepresents an impedance of the capacitance (Cp). By determining the impedances Zto Zsuch that this bridge circuit is balanced, a potential at a receiving-device-side reference potential point is made equal to a ground potential. This reduces variation in receiving-device-side reference potential, reduces noise, and stabilizes the operation of a load circuit on the receiving device side.

Power transfer system

A power transmission apparatus includes capacitors connected in series between an active electrode and a passive electrode. A power reception apparatus includes capacitors connected in series between an active electrode and a passive electrode. When a capacitance between the active electrodes is represented by Caa, a capacitance between the passive electrodes is represented by Cpp, and reactances of the capacitors are represented by X1, X2, X3, and X4; the active electrodes, the passive electrodes and the capacitors are configured such that Cpp/Caa=X1/X2=X3/X4 and Cpp&#x2267;Caa are satisfied. Thus, a wireless power transmission system capable of stabilizing an operation of a load circuit in the power reception apparatus is provided.

Wireless power transmission system

An electric power transmitting apparatus and a method for controlling electric power transmission that switches a connection state of a coupling electrode in accordance with the shape and the size of an electric power receiving apparatus, and a position where the electric power receiving apparatus is placed.

Electric power transmitting apparatus and method for controlling electric power transmission

An active electrode and a passive electrode are electrically field-coupled with an active electrode and a passive electrode provided in a power transmission device, respectively. Power in a high frequency voltage excited on the active electrode and the passive electrode is supplied to a mobile unit via a step-down transformer, a rectification smoothing circuit, and a DC-DC converter. A CPU turns off switches when wireless communication is carried out. The passive electrode functions as a booster antenna that is magnetically field-coupled with an antenna coil. A high frequency signal outputted from an RF circuit is transmitted via the antenna coil and the passive electrode, and a high frequency signal transmitted from the power transmission circuit is inputted, via the passive electrode and the antenna coil, to the RF circuit.

Power reception device, power transmission device, and power transmission system

Power transmission device that causes a power supply circuit to supply a first voltage to a first active electrode when power transmission is performed, causes the power supply circuit to supply a second voltage that is lower than the first voltage to the first active electrode and causes power reception device detection means to perform frequency sweeping at a first time interval until the power reception device is mounted, or causes the power supply circuit to supply a third voltage that is lower than the first voltage to the first active electrode and causes the power reception device detection means to perform frequency sweeping at a second time interval that is longer than the first time interval until the power reception device is removed.

Power transmission device and power transmission control method

When power transmitting electrodes of a power transmitting apparatus are respectively facing power receiving electrodes of a power receiving apparatus, a composite resonant circuit including a series resonant circuit and a parallel resonant circuit is formed through a compound capacitance formed between the power transmitting electrodes and the power receiving electrodes. In a predetermined mutually facing state in which the compound capacitance becomes maximum, the impedances of the configuration components of the composite resonant circuit are set such that a resonant frequency at which the impedance of the composite resonant circuit from a signal generator side when inputs of a load circuit is short-circuited becomes locally minimum, becomes higher than a resonant frequency at which the impedance of the composite resonant circuit as seen from the signal generator side when the inputs of the load circuit are open becomes locally maximum.

In a power transmitter device, a power transmitter side active electrode and a power transmitter side passive electrode are formed. In a power receiver device, a power receiver side active electrode and a power receiver side passive electrode are formed. The power transmitter side active electrode is rectangle that is shorter in a first direction and longer in a second direction. The power receiver side active electrode is rectangle that is longer in the first direction and shorter in the second direction. The power transmitter side active electrode and the power receiver side active electrode are formed so as that lengths of overlapping area in the first and second directions do not change in a placement receivable area on the power transmitter device, within which the power receiver device is allowed to be displaced.

Growing community of inventors

Nagaokakyo, Japan

Tsuyoshi Suesada