Abstract: Provided are a power reception device and a power reception control method capable of suppressing the application of an excessive voltage even in the case where a time lag occurs before power transmission by a power transmission device is stopped after disconnection between the power reception device and a load. A power reception device includes: a power reception coil that receives power transmitted from a power transmission coil; a rectification circuit that rectifies alternating current power received by the power reception coil; and a control circuit that is connected between the rectification circuit and a load to which direct current power outputted from the rectification circuit is supplied, and controls that the direct current flowing through the load to be constant or equal to or less than a predetermined value by the direct current power.

Abstract: Provided is a power feeding apparatus in a power feeding system that is configured to transmit, in a contactless fashion, electric power from the power feeding apparatus to a power receiving apparatus by magnetic coupling. The power feeding apparatus includes a power feeding resonator, a power supply, a communicator, and a controller. The power supply is configured to output a high-frequency signal to the power feeding resonator. The communicator is configured to receive load information from the power receiving apparatus. The load information includes information on at least a voltage between the voltage and a current of a load coupled to the power receiving apparatus. The controller is configured to perform, on the power supply, a control of the high-frequency signal on a basis of the load information received by the communicator, after starting of the output of the high-frequency signal by the power supply.

Abstract: Provided are a power reception device and a power reception control method capable of suppressing the application of an excessive voltage even in the case where a time lag occurs before power transmission by a power transmission device is stopped after disconnection between the power reception device and a load. A power reception device includes: a power reception coil that receives power transmitted from a power transmission coil; a rectification circuit that rectifies alternating current power received by the power reception coil; and a control circuit that is connected between the rectification circuit and a load to which direct current power outputted from the rectification circuit is supplied, and controls that the direct current flowing through the load to be constant or equal to or less than a predetermined value by the direct current power.

Abstract: Provided is a power feeding apparatus in a power feeding system that is configured to transmit, in a contactless fashion, electric power from the power feeding apparatus to a power receiving apparatus by magnetic coupling. The power feeding apparatus includes a power feeding resonator, a power supply, a communicator, and a controller. The power supply is configured to output a high-frequency signal to the power feeding resonator. The communicator is configured to receive load information from the power receiving apparatus. The load information includes information on at least a voltage between the voltage and a current of a load coupled to the power receiving apparatus. The controller is configured to perform, on the power supply, a control of the high-frequency signal on a basis of the load information received by the communicator, after starting of the output of the high-frequency signal by the power supply.

Abstract: An inverter control circuit (6) controls the operation of a plurality of switching elements in a three-phase inverter circuit (2) by a PWM signal. A phase voltage output from the three-phase inverter circuit (2) is outputted through a low-pass filter (3). A waveform of the phase voltage output from the low-pass filter (3) assumes the following waveforms through the control of the PWM signal. The waveform becomes zero in a first one-third period of a cycle; forms a sine wave corresponding to a phase from 0 to 2?/3 in a second one-third period; and forms a sine wave corresponding to a phase from ?/3 to ? in a remaining one-third period of the cycle. Such PWM signal cyclically includes a period where a pulse is not generated. Therefore, the switching action of the switching element is periodically stopped.

Abstract: An inverter control circuit (6) controls the operation of a plurality of switching elements in a three-phase inverter circuit (2) by a PWM signal. A phase voltage output from the three-phase inverter circuit (2) is outputted through a low-pass filter (3). A waveform of the phase voltage output from the low-pass filter (3) assumes the following waveforms through the control of the PWM signal. The waveform becomes zero in a first one-third period of a cycle; forms a sine wave corresponding to a phase from 0 to 2?/3 in a second one-third period; and forms a sine wave corresponding to a phase from ?/3 to ? in a remaining one-third period of the cycle. Such PWM signal cyclically includes a period where a pulse is not generated. Therefore, the switching action of the switching element is periodically stopped.