Wireless power transmission apparatus and power transfer system

A power transfer system comprising:

• a power transmission apparatus;
• and
• a power reception apparatus configured to wirelessly receive electric power from the power transmission apparatus,
• the power transmission apparatus including:
• a power transmission device configured to wirelessly transmit the electric power to the power reception apparatus;
• an inverter configured to generate transmission power having a prescribed frequency and supply the transmission power to the power transmission device;
• and
• a control device configured to control the inverter,
• the control device being configured to:
• adjust magnitude of the transmission power by adjusting a duty of an output voltage of the inverter;
• adjust the frequency by controlling the inverter;
• execute first control for adjusting the frequency such that a loss of the inverter decreases while maintaining the transmission power, when a temperature of the inverter exceeds a limit temperature;
• and
• execute second control for reducing the transmission power, when the temperature of the inverter exceeds the limit temperature even if the first control is executed.