Wireless power supply system, power transmitter, and power transmission method

A power transmitter, including a primary-side resonant coil, for transmitting electric power to a plurality of power receivers including secondary-side resonant coils configured to receive the electric power from the primary-side resonant coil through magnetic field resonance or electric field resonance generated with the primary-side resonant coil,

• wherein the power transmitter groups the plurality of power receivers into a plurality of first groups based on degrees of coupling between the power transmitter and the respective power receivers in an initial state,
• wherein the power transmitter calculates, for the respective first groups, charging times required to charge all the power receivers, and calculates a first total charging time obtained by totaling the charging times for all the first groups,
• wherein the power transmitter sets, to the power receivers, degrees of coupling that are greater than or equal to the degrees of coupling in the initial state,
• wherein the power transmitter again groups the plurality of power receivers into a plurality of second groups based on the set degrees of coupling,
• wherein the power transmitter calculates, for the respective second groups, charging times required to charge all the power receivers, and calculates a second total charging time obtained by totaling the charging times for the second groups, and
• wherein the power transmitter starts to transmit the electric power when the second total charging time is less than or equal to the first total charging time.

A power transmission method in a wireless power supply system, the wireless power supply system including a power transmitter including a primary-side resonant coil and configured to transmit electric power;

• and a plurality of power receivers including secondary-side resonant coils configured to receive the electric power from the primary-side resonant coil through magnetic field resonance or electric field resonance generated with the primary-side resonant coil, the power receivers including adjustment units configured to adjust degrees of coupling with the power transmitter, the power transmission method comprising:
• causing the power transmitter to group the plurality of power receivers into a plurality of first groups based on degrees of coupling between the power transmitter and the respective power receivers in an initial state;
• causing the power transmitter to calculate, for the respective first groups, charging times required to charge all the power receivers, and to calculate a first total charging time obtained by totaling the charging times for all the first groups;
• causing the power transmitter to adjust the adjustment units to set the degrees of coupling that are greater than or equal to the degrees of coupling in the initial state;
• causing the power transmitter to again group the plurality of power receivers into a plurality of second groups based on the set degrees of coupling;
• causing the power transmitter to calculate, for the respective second groups, charging times required to charge all the power receivers, and to calculate a second total charging time obtained by totaling the charging times for the second groups;
• and
• causing the power transmitter to start to transmit the electric power when the second total charging time is less than or equal to the first total charging time.