Wireless power transmission device
A coil structure for wireless power transmission is provided. The coil structure comprises: a primary resonance coil wound in a spiral shape around a centripetal point; a primary induction coil, which supplies power to the primary resonance coil in a nonconnected state with an input or output terminal of the primary resonance coil and is wound in a spiral shape on a substantially same plane around a substantially same centripetal point as the centripetal point; a switch configured to be parallel with the primary resonance coil so as to control the ON and OFF of an operation of the primary resonance coil; and a capacitor coupled to the primary resonance coil so as to form a magnetic resonance with the primary resonance coil.
1 . A wireless power transmission apparatus, comprising:
a primary inductive coil for a first wireless power transmission mode;
a primary resonant coil for a second wireless power transmission mode, wherein at least a portion of the primary resonant coil is wound with the primary inductive coil around approximately a same center point and in approximately a same plane;
a switch connected to the primary resonant coil; and
a control circuit configured to:
detect a wireless power reception apparatus,
send a first control signal for turning off the switch when the wireless power reception apparatus is a first type associated with the first wireless power transmission mode, and
send a second control signal for turning on the switch when the wireless power reception apparatus is a second type associated with the second wireless power transmission mode.
2 . The wireless power transmission apparatus of claim 1 , further comprising:
a primary core including both the primary resonant coil and the primary inductive coil; and
a driving circuit configured to provide a driving signal to the primary core after the control circuit detects the wireless power reception apparatus.
3 . The wireless power transmission apparatus of claim 1 , wherein the switch is connected through a first capacitor to one location on the primary resonant coil and through a second capacitor to a second location on the primary resonant coil.
4 . The wireless power transmission apparatus of claim 3 , wherein at least one of the first capacitor or the second capacitor is connected to an end of the primary resonant coil to form a magnetic resonance of the primary resonant coil.
5 . The wireless power transmission apparatus of claim 3 , wherein the first capacitor and the second capacitor are connected in series with the switch and respective ends of the primary resonant coil.
6 . The wireless power transmission apparatus of claim 1 , wherein the second wireless power transmission mode includes the primary inductive coil supplying power to the primary resonant coil in a contactless form with the primary resonant coil.
7 . The wireless power transmission apparatus of claim 1 , wherein the primary resonant coil and the primary inductive coil are formed by bi-filar conductive wires that are not electrically connected to each other.
8 . The wireless power transmission apparatus of claim 1 , wherein the primary resonant coil and the primary inductive coil are wound side by side at an inner side close to the center point and the primary resonant coil is extended and wound at an outer side distant from the center point.
9 . The wireless power transmission apparatus of claim 1 , wherein the primary resonant coil is extended and wound at an inner side close to the center point and the primary resonant coil and the primary inductive coil are wound side by side at an outer side distant from the center point.
10 . The wireless power transmission apparatus of claim 1 , wherein a length of the primary resonant coil is based on a wavelength of a resonance frequency for the second wireless power transmission mode.
11 . The wireless power transmission apparatus of claim 10 , wherein the length of the primary resonant coil is equal to the wavelength of the resonance frequency divided by a power of 2.
12 . The wireless power transmission apparatus of claim 1 ,
wherein the first wireless power transmission mode includes magnetic induction coupling between the primary inductive coil and a secondary coil of the wireless power reception apparatus, and
wherein the second wireless power transmission mode includes magnetic resonance coupling between the primary resonant coil and the secondary coil of the wireless power reception apparatus.
13 . The wireless power transmission apparatus of claim 1 , wherein the switch comprises a plurality of Field Effect Transistors (FETs), the plurality of FETs maintaining a switch-on state regardless of a phase of a voltage applied to the primary resonant coil.
14 . A method for wireless power transmission, comprising:
detecting a wireless power reception apparatus;
controlling a driving circuit connected to a primary core, the primary core including both a primary inductive coil for a first wireless power transmission mode and a primary resonant coil for a second wireless power transmission mode, wherein at least a portion of the primary resonant coil is wound with the primary inductive coil around approximately a same center point and in approximately a same plane; and
controlling a switch connected to the primary resonant coil, wherein controlling the switch includes:
sending a first control signal for turning off the switch when the wireless power reception apparatus is a first type associated with the first wireless power transmission mode, and
sending a second control signal for turning on the switch when the wireless power reception apparatus is a second type associated with the second wireless power transmission mode.
15 . The method of claim 14 , wherein controlling the switch includes:
selecting the first wireless power transmission mode or the second wireless power transmission mode based on whether the wireless power reception apparatus is the first type or the second type.
16 . The method of claim 14 , further comprising concurrently transmitting wireless power via the primary resonant coil and the primary inductive coil.
17 . The method of claim 14 , further comprising:
in the second wireless power transmission mode, supplying power from the primary inductive coil to the primary resonant coil in a contactless form.
18 . The method of claim 14 ,
wherein the first wireless power transmission mode includes magnetic induction coupling between the primary inductive coil and a secondary coil of the wireless power reception apparatus, and
wherein the second wireless power transmission mode includes magnetic resonance coupling between the primary resonant coil and the secondary coil of the wireless power reception apparatus.
19 . The method of claim 14 , wherein detecting the wireless power reception apparatus includes:
detecting an object in a ping phase during a charging standby state; and
determining that the object is the wireless power reception apparatus based on a communication from the wireless power reception apparatus.
20 . The method of claim 14 , further comprising:
entering a charging state for transmission of wireless power according to the first wireless power transmission mode or the second wireless power transmission mode;
measuring a current flowing in the primary core; and
detecting a foreign object based on the current flowing in the primary core; and
interrupting the transmission of the wireless power based on detecting the foreign object.