Power transmission apparatus for wirelessly transmitting AC power switched at a timing based on a corrected clock signal, and method of controlling same
A power transmission unit 100 includes a clock generation circuit 105 that generates a clock signal, a switch circuit 102 that switches alternating-current power at a timing based on the clock signal, a power transmission antenna 101 that wirelessly transmits the switched alternating-current power, and a transmission antenna 103 that wirelessly transmits the clock signal. A power reception unit 200 includes a power reception antenna 201 that receives the power transmitted from the power transmission antenna, a reception antenna 203 that receives the clock signal transmitted from the transmission antenna, and a rectification circuit 202 that switches the power at a timing based on the received clock signal. A first correction circuit 106 corrects the phase of the clock signal to reduce a phase shift between a phase of the alternating-current power input from the rectification circuit and a phase of the clock signal input from the rectification circuit.
1 . A power transmission apparatus configured to wirelessly transmit alternating-current power to a power reception apparatus configured to be movable relative to the power transmission apparatus in a predetermined direction, the power transmission apparatus comprising:
an alternating-current source configured to output alternating-current power having a first frequency;
a clock generation circuit configured to generate a clock signal;
a clock transmission circuit configured to transmit the clock signal;
a correction circuit configured to correct a phase of the generated clock signal;
a switch circuit configured to be connected to the alternating-current source and including a bidirectional switch configured to switch the alternating-current power output from the alternating-current source at a second frequency which is higher than the first frequency at a timing based on the corrected clock signal;
a power transmission antenna stretched in the predetermined direction, connected to the switch circuit and configured to wirelessly transmit the alternating-current power having the second frequency and being output from the switch circuit to the power reception apparatus; and
a transmission antenna stretched in the predetermined direction, connected to the clock transmission circuit and configured to wirelessly transmit the generated clock signal;
wherein the correction circuit is configured to vary an amount of correction of the phase of the generated clock signal using at least acquired positional information on a position at which the power reception apparatus is located relative to the power transmission apparatus in the predetermined direction.
2 . The power transmission apparatus according to claim 1 , wherein the amount of correction made by the correction circuit is predetermined based on a specified operation sequence of a control system including the power transmission apparatus and the power reception apparatus.
3 . A method of controlling a power transmission apparatus configured to wirelessly transmit alternating-current power to a power reception apparatus configured to be movable relative to the power transmission apparatus in a predetermined direction, the method comprising:
outputting from an alternating-current source alternating-current power having a first frequency;
performing clock generation to generate a clock signal;
correcting a phase of the generated clock signal;
switching the alternating-current power output from the alternating-current source at a second frequency which is higher than the first frequency at a timing based on the corrected clock signal using a switch circuit connected to the alternating-current source and including a bidirectional switch;
wirelessly transmitting from a power transmission antenna stretched in the predetermined direction and connected to the switch circuit the alternating-current power having the second frequency and being output from the switch circuit to the power reception apparatus; and
wirelessly transmitting the generated clock signal from a transmission antenna stretched in the predetermined direction and connected to a clock transmission circuit;
wherein in the correcting, an amount of correction of the phase of the generated clock signal is varied using at least acquired positional information on a position at which the power reception apparatus is located relative to the power transmission apparatus in the predetermined direction.
4 . A wireless power transmission system comprising:
a power transmission apparatus and a power reception apparatus;
the power transmission apparatus comprising:
an alternating-current source configured to output alternating-current power having a first frequency;
a clock generation circuit configured to generate a clock signal;
a clock transmission circuit configured to transmit the clock signal;
a correction circuit configured to correct a phase of the generated clock signal;
a switch circuit configured to be connected to the alternating-current source and including a bidirectional switch configured to switch the alternating-current power output from the alternating-current source at a second frequency which is higher than the first frequency at a timing based on the corrected clock signal;
a power transmission antenna stretched in a predetermined direction, connected to the switch circuit and configured to wirelessly transmit the alternating-current power having the second frequency and being output from the switch circuit to the power reception apparatus; and
a transmission antenna stretched in the predetermined direction, connected to the clock transmission circuit and configured to wirelessly transmit the generated clock signal; and
the power reception apparatus comprising:
a power reception antenna of which a length in the predetermined direction is shorter than a length in the predetermined direction of the power transmission antenna;
a reception antenna of which a length in the predetermined direction is shorter than a length in the predetermined direction of the transmission antenna;
a power reception circuit configured to connect to the power reception antenna; and
a reception circuit configured to connect to the reception antenna.
5 . The wireless power transmission system according to claim 4 , wherein the power reception apparatus further comprises a movement control unit configured to perform control on movement in the predetermined direction.
6 . The wireless power transmission system according to claim 4 , wherein the power transmission apparatus further comprises a positional information acquisition unit configured to acquire positional information on a position at which the power reception apparatus is located relative to the power transmission apparatus in the predetermined direction.
7 . The wireless power transmission system according to claim 6 , wherein the correction circuit is configured to vary an amount of correction of the phase of the generated clock signal using at least the acquired positional information.
8 . The wireless power transmission system according to claim 4 , wherein the power reception circuit includes the bidirectional switch.