Wireless charging system and wireless charging transmission apparatus and method changing frequency to transmit power

1. A wireless power transmission apparatus which is configured to transmit charging electric power for charging a battery electrically connected to a power reception side apparatus to the power reception side apparatus by magnetic resonance, and to perform charging of the battery electrically connected to the power reception side apparatus, the wireless power transmission apparatus comprising:

a power transmission unit;

a controlling device configured to control alternating current power, which is supplied to the power transmission unit, to transmit a small electric power, which is lower than the charging electric power, for switching a state of the power reception side apparatus from a standby state, in which the battery can not be charged by the transmitted electric power, to a start state, in which the battery can be charged by the transmitted electric power, from the power transmission unit to a power reception unit of the power reception side apparatus before charging the battery; and

a communication device which configures a communication path, which is different from a power transmission path including the power transmission unit and the power reception unit of the power reception side apparatus, between the power reception side apparatus, and which is configured to perform dual-directional wireless communication through the communication path, wherein,

the controlling device controls the alternating current power to output the small electric power while changing frequency of the alternating current power from a first value to a second value, the second value being different from the first value, for making a receiving voltage of the small electric power received via the power reception unit be greater than a threshold value and thereby causing switching the state of the power reception side apparatus from the standby state to the start state, and

wherein the controlling device controls the alternating current power to transmit the charging electric power from the power transmission unit to the power reception unit upon information being received through the communication device indicating that the power reception side apparatus is in the start state.

2. A wireless charging system which is configured to transmit charging electric power for charging a battery electrically connected to a power reception side apparatus from a power transmission side apparatus to the power reception side apparatus by magnetic resonance, wherein

the power reception side apparatus comprises:

a power reception unit;

a switching device configured to switch a state of the power reception side apparatus to a standby state, in which the battery can not be charged, or a start state, in which the battery can be charged; and

a power reception side communication device,

the power transmission side apparatus comprises:

a power transmission unit;

a controlling device configured to control alternating current power, which is supplied to the power transmission unit, to transmit a small electric power for switching the state of the power reception side apparatus from the standby state to the start state before charging the battery, the small electric power being lower than the charging electric power; and

a power transmission side communication device,

the power reception side communication device and the power transmission side communication device performs dual-directional wireless communication through a communication path which is different from a power transmission path including the power transmission unit and the power reception unit,

wherein, when the power reception unit receives the small electric power with a receiving voltage of the small electric power that is greater than a threshold value, the switching device switches the state of the power reception side apparatus from the standby state to the start state,

wherein, for making the receiving voltage of the small electric power received via the power reception unit be greater than the threshold value, the controlling device controls a frequency of the alternating current power to output the small electric power initially at a first frequency and then changing the small electric power to a second frequency, the second frequency being different from the first frequency, wherein changing the frequency of the small electric power from the first frequency to the second frequency makes the receiving voltage of the small electric power received via the power reception unit be greater than the threshold value thereby causing switching of the state of the power reception side apparatus from the standby state to the start state, and

wherein, the power transmission side communication device receiving information indicating that the power reception side apparatus is in the start state causes the controlling device to control the alternating current power to transmit the charging electric power from the power transmission unit to the power reception unit.

3. The wireless charging system according to claim 2 , wherein the small electric power is an amount of electric power which does not exceed a rated value regarding electricity of components which constitute the power reception side apparatus.

4. The wireless charging system according to claim 2 , wherein the power reception side communication device is allowed to perform communication with the power transmission side communication device on condition that the power reception unit received the small electric power.

5. The wireless charging system according to claim 4 , wherein the power reception side communication device is allowed to perform communication with the power transmission side communication device by supplying power caused by the power reception unit receiving the small electric power.

6. A wireless power transmission method performed by a wireless power transmission apparatus which comprises (i) a power transmission unit, and (ii) a communication device which configures a communication path, which is different from a power transmission path including the power transmission unit and a power reception unit of a power reception side apparatus, between the power reception side apparatus, and which is configured to perform dual-directional wireless communication through the communication path, and which transmits charging electric power for charging a battery electrically connected to the power reception side apparatus to the power reception side apparatus by magnetic resonance,

the wireless power transmission method comprising:

a first controlling process for controlling alternating current power, which is supplied to the power transmission unit, to transmit a small electric power, which is lower than the charging electric power, for switching a state of the power reception side apparatus from a standby state, in which the battery can not be charged by the transmitted electric power, to a start state, in which the battery can be charged by the transmitted electric power, from the power transmission unit to the power reception unit before charging the battery; and

a second controlling process for controlling the alternating current power to transmit the charging electric power from the power transmission unit to the power reception unit upon receiving information through the communication device indicating that the power reception side apparatus is in the start state,

wherein the first controlling process controls the alternating current power to output the small electric power while changing frequency of the alternating current power from a first value to a second value, the second value being different from the first value, for making receiving voltage of the small electric power received via the power reception unit be greater than a threshold value for causing switching the state of the power reception side apparatus from the standby state to the start state.