| 摘要 |
A power transmission device has: a power transmission unit configured to perform wireless power transmission; a communication unit configured to perform wireless communication within a range wider than a power transmission possible range of the power transmission unit; and a power transmission control circuit configured to control power of wireless power transmission of the power transmission unit, wherein the power transmission control circuit controls the power of wireless power transmission of the power transmission unit (S508) according to a number of power reception devices for which the communication unit received a response (S502) indicating that power reception is performed from power reception devices receiving power equal to or more than a threshold when the power transmission unit performs power transmission by first power (S501), and a number of power reception devices for which the communication unit received a response (S505) indicating that power reception is performed from power reception devices receiving power equal to or more than the threshold when the power transmission unit does not perform power transmission (S504) or performs power transmission by second power smaller than the first power. |
