Abstract: A power conversion device comprises an inner coil which can transmit power between an external coil by coupling magnetically with the external coil, an inverter whose AC side is connected to the inner coil and power conversion can be performed between the AC side and a DC side and a bidirectional DC/DC converter which comprises an intermediate capacitor, is connected to the DC side of the inverter and can perform power conversion bidirectionally between a DC power source, which is connected to a side which is opposite to the side of the inverter, and the inverter, wherein in switching operation from power reception to power transmission where power reception operation is switched to power transmission operation, after control of discharging charges which are accumulated in the intermediate capacitor is performed, the power transmission operation is started.

Abstract: A power conversion device comprises an inner coil which can transmit power between an external coil by coupling magnetically with the external coil, an inverter whose AC side is connected to the inner coil and power conversion can be performed between the AC side and a DC side and a bidirectional DC/DC converter which comprises an intermediate capacitor, is connected to the DC side of the inverter and can perform power conversion bidirectionally between a DC power source, which is connected to a side which is opposite to the side of the inverter, and the inverter, wherein in switching operation from power reception to power transmission where power reception operation is switched to power transmission operation, after control of discharging charges which are accumulated in the intermediate capacitor is performed, the power transmission operation is started.

Abstract: A power conversion device includes: an inverter for supplying high-frequency power to a coil; a harmonic filter connected to an output side of the inverter; and a controller for performing control to make a zero-cross point of an output current from the inverter coincide with a zero-cross point of a filter current of the harmonic filter. Through this, harmonic reduction effect can be fully exerted. Further, a contactless power supply system using the power conversion device can supply, to a load, power in which harmonics are significantly reduced, addressing a problem that inverter driving frequency cannot be controlled to a frequency at which harmonic reduction effect is maximized, and harmonic reduction effect cannot be fully exerted.

Abstract: A gate-drive system according to the present invention which transmits a drive signal to a semiconductor switching device, includes: an inverter circuit to supply high-frequency power including a fundamental wave component and plural harmonic components each having different frequencies; a power transmission circuit which is connected to the inverter circuit and transmits the high-frequency power outputted from the inverter circuit; power receiving circuits to individually receive the fundamental wave component and plural harmonic components of the high-frequency power transmitted from the power transmission circuit; and a control circuit to generate the drive signal for the semiconductor switching device on the basis of the plural harmonic components of the high-frequency power received by the power receiving circuits.

Abstract: A gate-drive system according to the present invention which transmits a drive signal to a semiconductor switching device, includes: an inverter circuit to supply high-frequency power including a fundamental wave component and plural harmonic components each having different frequencies; a power transmission circuit which is connected to the inverter circuit and transmits the high-frequency power outputted from the inverter circuit; power receiving circuits to individually receive the fundamental wave component and plural harmonic components of the high-frequency power transmitted from the power transmission circuit; and a control circuit to generate the drive signal for the semiconductor switching device on the basis of the plural harmonic components of the high-frequency power received by the power receiving circuits.

Abstract: A charging device for an electric vehicle includes a wireless power receiving device which receives high-frequency AC power in a non-contact state, a wired power receiving device connected to an external power source for low-frequency AC power, a rectifier which rectifies AC power, an electric power converter which is positioned at a rear part of the rectifier, and an power receiving device switching switch which switches electric power in such a way that any of electric power of both electric power receiving devices is outputted to the rectifier. A high-frequency filter, which removes a high-frequency component, is provided between the rectifier and the electric power converter.

Abstract: A power conversion device includes: an inverter for supplying high-frequency power to a coil; a harmonic filter connected to an output side of the inverter; and a controller for performing control to make a zero-cross point of an output current from the inverter coincide with a zero-cross point of a filter current of the harmonic filter. Through this, harmonic reduction effect can be fully exerted. Further, a contactless power supply system using the power conversion device can supply, to a load, power in which harmonics are significantly reduced, addressing a problem that inverter driving frequency cannot be controlled to a frequency at which harmonic reduction effect is maximized, and harmonic reduction effect cannot be fully exerted.

Abstract: A bidirectional non-contact power supply device with its electric power transmission efficiency being high is obtained by a simple configuration. In the bidirectional non-contact power supply device, a coil is included for performing electric power transmission to and reception from another coil through a magnetic field coupling therebetween, and the coil and a capacitor being connected in series are connected on an input-output end of an inverter circuit, wherein a bidirectional buck-boost converter is connected between the inverter circuit and a DC power source (7).

Abstract: A bidirectional non-contact power supply device with its electric power transmission efficiency being high is obtained by a simple configuration. In the bidirectional non-contact power supply device, a coil is included for performing electric power transmission to and reception from another coil through a magnetic field coupling therebetween, and the coil and a capacitor being connected in series are connected on an input-output end of an inverter circuit, wherein a bidirectional buck-boost converter is connected between the inverter circuit and a DC power source (7).

Abstract: A charging device for an electric vehicle includes a wireless power receiving device which receives high-frequency AC power in a non-contact state, a wired power receiving device connected to an external power source for low-frequency AC power, a rectifier which rectifies AC power, an electric power converter which is positioned at a rear part of the rectifier, and an power receiving device switching switch which switches electric power in such a way that any of electric power of both electric power receiving devices is outputted to the rectifier. A high-frequency filter, which removes a high-frequency component, is provided between the rectifier and the electric power converter.

Abstract: A gate-power-supply device is provided with an inverter circuit, a transformer, and rectifier circuits. The device includes secondary-side parallel capacitors, connected in parallel to secondary-side coils of the transformer, for cancelling inductance components of the secondary-side coils at the drive frequency of the inverter circuit. The device includes a primary-side series capacitor, connected in series to a primary-side coil of the transformer, for cancelling the imaginary term (inductance component) of the combined impedance of the gate drivers, the rectifier circuits, the secondary-side parallel capacitors, the secondary-side coils, transformer cores and the primary-side coil, which are a load viewed from the inverter circuit.

Abstract: A gate-power-supply device is provided with an inverter circuit, a transformer, and rectifier circuits. The device includes secondary-side parallel capacitors, connected in parallel to secondary-side coils of the transformer, for cancelling inductance components of the secondary-side coils at the drive frequency of the inverter circuit. The device includes a primary-side series capacitor, connected in series to a primary-side coil of the transformer, for cancelling the imaginary term (inductance component) of the combined impedance of the gate drivers, the rectifier circuits, the secondary-side parallel capacitors, the secondary-side coils, transformer cores and the primary-side coil, which are a load viewed from the inverter circuit.