Power transmitting apparatus and power transmission system

A power transmission system comprising:

• a power transmitting apparatus including:
• primary side coupling electrodes,
• a high-frequency voltage generator circuit adapted to apply a high-frequency voltage across the primary side coupling electrodes, and
• a driving power supply circuit adapted to supply driving power to the high-frequency voltage generator circuit;
• and
• a power receiving apparatus including:
• secondary side coupling electrodes, and
• a high-frequency voltage load circuit connected to the secondary side coupling electrodes,
• wherein, the power receiving apparatus has a resonant circuit formed of the secondary side coupling electrodes and the high-frequency voltage load circuit,
• wherein the primary side coupling electrodes of the power transmitting apparatus and the secondary side coupling electrodes of the power receiving apparatus side coupling electrodes are adapted to capacitively couple to each other to transmit power, and
• wherein the power transmitting apparatus further includes:
• a driving power supply switching unit adapted to allow the driving power supply circuit to supply either a constant current or a constant voltage to the high-frequency voltage generator circuit,
• a voltage detection unit adapted to detect a voltage supplied to the high-frequency voltage generator circuit, and
• a control unit adapted to detect a frequency at which the voltage supplied to the high-frequency voltage generator circuit becomes a maximal voltage for a change in frequency of a voltage generated by the high-frequency voltage generator circuit, in a state in which the constant current is supplied, to set the frequency corresponding to the maximal voltage as the frequency of the voltage generated by the high-frequency voltage generator circuit, and to perform switching so as to supply the constant voltage.