Contactless power supply device, contactless power reception device, and contactless power supply system

A contactless power reception device that receives electric power supplied to a vehicle in a contactless manner, the power reception device comprising:

• a power reception resonance circuit;
• and
• a power reception circuit that converts alternating-current power received by the power reception resonance circuit into direct-current power and supplies the direct-current power to a load, wherein
• the power reception circuit includes:
• a power reception-side immittance conversion circuit that adjusts the alternating-current power input from the power reception resonance circuit;
• a rectification circuit that converts the alternating-current power input from the power reception-side immittance conversion circuit into direct-current power;
• and
• a power conversion circuit that converts the direct-current power input from the rectification circuit into power suppliable to the load, and
• a characteristic impedance of the power reception-side immittance conversion circuit is ⅕ or less of an impedance forward on the power reception resonance circuit-side from the power reception-side immittance conversion circuit.

A contactless power supply system that, by using a plurality of power transmission resonance circuits arranged in a road and a power reception resonance circuit mounted in a vehicle, supplies electric power to the vehicle in a contactless manner, the contactless power supply system comprising:

• a contactless power supply device that has the plurality of power transmission resonance circuits;
• and
• a contactless power reception device that is mounted in the vehicle, wherein:
• the contactless power supply device includes:
• the plurality of power transmission resonance circuits;
• a power source circuit that supplies direct-current power;
• and
• a plurality of power transmission circuits that convert the direct-current power of the power source circuit into alternating-current power and supply the alternating-current power to the plurality of power transmission resonance circuits;
• the power transmission circuits each include:
• an inverter circuit that converts the direct-current power of the power source circuit into alternating-current power;
• and
• a power transmission-side immittance conversion circuit that adjusts the alternating-current power of the inverter circuit and supplies the alternating-current power to the power transmission resonance circuits,
• a characteristic impedance of the power transmission-side immittance conversion circuit being ⅕ or less of an impedance backward on the power transmission resonance circuit-side from the power transmission-side immittance conversion circuit;
• the contactless power reception device includes:
• the power reception resonance circuit;
• and
• a power reception circuit that converts the alternating-current power received by the power reception resonance circuit into direct-current power and supplies the direct-current power to a load;
• and
• the power reception circuit includes:
• a power reception-side immittance conversion circuit that adjusts the alternating-current power input from the power reception resonance circuit;
• a rectification circuit that converts the alternating-current power input from the power reception-side immittance conversion circuit into direct-current power;
• and
• a power conversion circuit that converts the direct-current power input from the rectification circuit into power suppliable to the load,
• a characteristic impedance of the power reception-side immittance conversion circuit being ⅕ or less of an impedance forward on the power reception resonance circuit-side from the power reception-side immittance conversion circuit.