Wireless power transmission system

A wireless power transmission system comprising:

• a power transmission apparatus;
• a power reception apparatus;
• and
• N (N is an integer equal to or larger than 2) relay apparatuses that are arranged between the power transmission apparatus and the power reception apparatus and that are sorted as first to N-th relay apparatuses in descending order of closeness to the power transmission apparatus,
• wherein the power transmission apparatus includes
• a power transmission inverter circuit that converts power transmission direct current power supplied from an external power supply into power transmission alternating current power, and
• a power transmission power transmission antenna that wirelessly transmits the power transmission alternating current power,
• wherein the first one of the N relay apparatuses includes
• a first relay power reception antenna that is electromagnetically coupled with the power transmission power transmission antenna and that receives the transmitted power transmission alternating current power,
• a first relay rectifier that converts the received power transmission alternating current power into first relay direct current power,
• a first relay inverter circuit that converts the first relay direct current power into first relay alternating current power, and
• a first relay power transmission antenna that wirelessly transmits the obtained first relay alternating current power,
• wherein an i-th (i=2 to N) one of the N relay apparatuses includes
• an i-th relay power reception antenna that is electromagnetically coupled with an (−1)th relay power transmission antenna and that receives (−1)th relay alternating current power,
• an i-th relay rectifier that converts the received (−1)th relay alternating current power into i-th relay direct current power,
• an i-th relay inverter circuit that converts the i-th relay direct current power into i-th relay alternating current power, and
• an i-th relay power transmission antenna that wirelessly transmits the obtained i-th relay alternating current power,
• wherein the power reception apparatus includes
• a power reception power reception antenna that is electromagnetically coupled with an N-th relay power transmission antenna and that receives N-th relay alternating current power, and
• a power reception rectifier that converts the N-th relay alternating current power received by the power reception power reception antenna into power reception direct current power,
• wherein the first relay apparatus also includes
• a first relay amplitude modulator that transmits binary first relay transmission data to the power transmission apparatus through the electromagnetic coupling between the first relay power reception antenna and the power transmission power transmission antenna by varying amplitude of voltage of the power transmission alternating current power received by the first relay power reception antenna between a first first amplitude and a first second amplitude,
• wherein the i-th (i=2 to N) relay apparatus also includes
• an i-th relay amplitude modulator that transmits binary i-th relay transmission data to the (−1)th relay apparatus through the electromagnetic coupling between the i-th relay power reception antenna and the (−1)th relay power transmission antenna by varying amplitude of voltage of the (−1)th relay alternating current power received by the i-th relay power reception antenna between an i-th first amplitude and an i-th second amplitude, and
• wherein the (−1)th (i=2 to N) relay apparatus also includes
• an (−1)th relay demodulator that is connected to the (−1)th relay power transmission antenna and that receives binary (−1)th relay received data by demodulating the binary i-th relay transmission data on the basis of a change in the voltage of the (−1)th relay alternating current power input to the (−1)th relay power transmission antenna, and
• an (−1)th relay reverse control circuit that reverses a sign of the binary (i−1)th relay received data received by the (−1)th relay demodulator and that causes the (−1)th relay amplitude modulator to eliminate a difference between a first voltage of the (−1)th relay direct current power, which corresponds to the i-th first amplitude, and a second voltage of the (−1)th relay direct current power, which corresponds to the i-th second amplitude, on the basis of the reversed binary (i−1)th relay received data.