Power transmission device and power reception device

A power transmission device comprising:

• a power transmission circuit configured to transmit power to a power reception device by contactless power transmission;
• a power conversion circuit configured to generate supply power to be supplied to the power transmission circuit using power of a first power supply, and supply the supply power to the power transmission circuit;
• and
• a processor configured to acquire information about a terminal voltage of a second power supply charged with power received by the power reception device and control the power conversion circuit, and configured to execute power feeding control for controlling the supply power via the power conversion circuit such that the terminal voltage comes to a target voltage,
• wherein the processor is configured to:
• acquire characteristic information of a system that charges the second power supply, from the power reception device, before executing the power feeding control;
• and
• control the supply power during the power feeding control based on the acquired characteristic information,
• the characteristic information includes transfer function information related to a transfer function of the system,
• the processor is configured to control the supply power during the power feeding control based on the transfer function information,
• the system includes the power transmission circuit, and a power reception circuit configured to receive power transmitted from the power transmission circuit by contactless power transmission, in which the power reception device has the power reception circuit,
• the transfer function information is information indicating a pole and a zero of the transfer function, and
• the processor is configured to control the supply power based on the information indicating the pole and the zero such that a phase margin is 0 degree or more.