Wireless power transfer system, power transmission device, power receiving device, and control method of wireless power transfer system

A control method of a wireless power transfer system that includes a power receiving device and a plurality of power transmission devices performing power transfer to the power receiving device, the method comprising:

• the power receiving device
• transmitting request-power to the power transmission device, the request-power being power the power receiving device requests to be supplied with,
• the power transmission device
• when receiving the request-power from the power receiving device, generating determination reference information based on the received request-power, the determination reference information being information to be used as a determination reference when the power receiving device selects the power transmission device, and
• transmitting the generated determination reference information to the power receiving device,
• the power receiving device
• receiving the determination reference information,
• selecting, based on the determination reference information, the power transmission device from which the power receiving device is to receive power supply, and
• transmitting a power transmission start request to the selected power transmission device, and
• the power transmission device
• starting power transfer to the power receiving device when receiving the power transmission start request.