Abstract: A code modulator transmits power to at least one code demodulator via a transmission path. The code modulator is provided with: a code modulation circuit to which output power of a power supply is supplied, the code modulation circuit modulating the output power of the power supply to generate a code-modulated wave by code modulation using a modulation code based on a code sequence, and transmitting the code-modulated wave to the code demodulator via the transmission path; and a control circuit that controls the code modulation circuit. The control circuit sets a frequency of the modulation code to a multiple of an output power frequency of the power supply.

Abstract: A current meter measures a current value associated with input power inputted to a code modulator. A code modulation circuit modulates the input power to generate a code-modulated wave by code modulation using a modulation code based on a code sequence, and transmits the code-modulated wave to the code demodulator via a transmission path. A control circuit controls the code modulation circuit. The code modulation circuit has operation modes different from each other depending on a direction of the input power, and a direction of the code-modulated wave to be generated. The control circuit generates waveform information indicating variations of direction of the input power over time, based on the current value measured by the current meter, and determines the operation mode of the code modulation circuit based on the waveform information.

Abstract: A control circuit of a code modulator sets first to third states to a code modulation circuit. In first state, first and fourth switch circuits are on, and second and third switch circuits are off. In second state, first and fourth switch circuits are off, and second and third switch circuits are on. In third state, all first to fourth switch circuits are on during transition from the first to second state, and vice versa. A control circuit of a code demodulator sets fourth to sixth states to a code demodulation circuit. In fourth state, fifth and eighth switch circuits are off, and sixth and seventh switch circuits are on. In fifth state, fifth and eighth switch circuits are on, and sixth and seventh switch circuits are off. In sixth state, all fifth to eighth switch circuits are on during transition from fourth to fifth state, and vice versa.

Abstract: The power transmitter apparatus is provided with code modulators which modulate powers of phase components of three-phase alternating-current power to generate code-modulated waves, respectively, by code modulation using modulation codes based on code sequences different from each other, and transmits the code-modulated waves to the at least one power receiver apparatus via the transmission path. The power receiver apparatus is provided with code demodulators, each of which demodulates one code-modulated wave of the received code-modulated waves to generate code-demodulated power by code demodulation using a demodulation code based on a code sequence identical to the code sequence of the modulation code used for the code modulation of the one code-modulated wave, the code-demodulated power being generated as power of one of phase components of multiphase alternating-current power.

Abstract: An electric power conversion device includes: a transformer including first and second windings magnetically coupled; a bridge circuit including a switch element; a rectifier circuit coupled to an output side of the transformer; a first resonant inductor; a second resonant inductor external to the transformer; and a resonant capacitor, wherein n1?n2, Cr>C1, and Lr>L2 where Lr is an inductance value of the first resonant inductor and L2 is an inductance value including an inductance value of the second resonant inductor and an inductance value of a parasitic inductance component that is in series with the second winding in the pathway from the second winding to the rectifier circuit.

Abstract: An electric power conversion device includes: a transformer including first and second windings magnetically coupled; a bridge circuit including a switch element; a rectifier circuit coupled to an output side of the transformer; a first resonant inductor; a second resonant inductor external to the transformer; and a resonant capacitor, wherein n1?n2, Cr>C1, and Lr>L2 where Lr is an inductance value of the first resonant inductor and L2 is an inductance value including an inductance value of the second resonant inductor and an inductance value of a parasitic inductance component that is in series with the second winding in the pathway from the second winding to the rectifier circuit.

Abstract: A magnetic device includes a winding, and insulators by which the winding is surrounded. Each of the insulators is in contact with the winding. A gap exists between each two adjacent of the insulators in a winding direction of the winding.

Abstract: An electric power conversion device includes: a transformer including first and second windings magnetically coupled; a bridge circuit including a switch element; a resonant inductor; and a resonant capacitor, wherein the resonant inductor and the resonant capacitor constitute a resonant circuit together with an inductance of the first winding, n1?n2, the resonant inductor is inserted into a pathway from the first connection point to the second connection point via the first winding in series with the first winding, the resonant capacitor is inserted into a pathway from the second winding to the output terminal in series with the second winding, and Cr>C1 where Cr is a capacitance of the resonant capacitor and C1 is a capacitance of a capacitance component that is in series with the first winding in the pathway from the first connection point to the second connection point via the first winding.