WIRELESS POWER TRANSMISSION SYSTEM FOR FREE-POSITION WIRELESS CHARGING OF MULTIPLE DEVICES

• US 20150302983A1
• Filed: 10/17/2013
• Published: 10/22/2015
• Est. Priority Date: 01/09/2013
• Status: Active Grant

• Current Assignee: Korea Electrotechnology Research Institute
• Original Assignee: Korea Electrotechnology Research Institute
• Inventors: PARK, Young Jin, KIM, Kwan Ho, KIM, Jin Wook, YANG, Jong Ryul
• Granted Patent: US 9,711,278 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01F 2027/2809 on stacked layers
• CPC Class Codes: H01F 27/2804 Printed windings
• CPC Class Codes: H01F 27/2823 Wires H01F27/2866 takes precedence
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/005 Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
• CPC Class Codes: H02J 50/12 of the resonant type

Abstract

The present invention relates to a near-field wireless power transfer system capable of having a constant efficiency regardless of a charging position of a receiver by only using a simple impedance matching circuit without using a separate existing complex adaptive impedance matching circuit or control circuit, and simultaneously transmitting power without having difficulty with impedance matching even for wireless power transmission to a plurality of electronic devices by applying a structure having a uniform mutual inductance between a wireless power transmitter and receiver.

Claims

1-37. -37. (canceled)

38. A wireless power transfer system for transmitting and receiving power between a transmitting coil of a transmitter and a receiving coil of a receiver via magnetic coupling, wherein:

the transmitting and receiving coils are configured such that center positions thereof are arranged at horizontally different positions to implement wireless power transfer in a way of horizontally free positioning, and are configured to transmit and receive power in a wireless manner via uniform mutual inductance within a preset range between the transmitting coil and the receiving coil.

39. The wireless power transfer system of claim 38, wherein multiple devices placed at horizontally different positions simultaneously charge batteries thereof using the uniform mutual inductance via receiving coils of corresponding receivers.

40. The wireless power transfer system of claim 38, wherein the transmitter comprises:

a unit for adjusting input impedance matching of the transmitter depending on multiple loads placed at horizontally different positions; and

a sensing circuit for sensing a variation in the input impedance looking into the transmitting coil depending on the loads and controlling the unit, thus performing impedance matching for the multiple loads.

41. The wireless power transfer system of claim 38, wherein:

the transmitter comprises a unit for input impedance matching of the transmitter between an Alternating Current (AC) source and the transmitting coil, and

the input impedance matching is possible via the unit within a range of a maximum number of multiple loads to be placed at horizontally different positions.

42. The wireless power transfer system of claim 41, wherein a source coil connected to the AC source is separated from the transmitting coil via magnetic coupling, and the input impedance matching is possible regardless of a variation in the maximum number of multiple loads by changing mutual inductance between the source coil and the transmitting coil according to a design of the transmitting coil.

43. A coil structure, comprising:

a coil part through which current flows in a direction of input current applied from a first end of the coil structure, the coil part being disposed between the first end and a second end of the coil structure; and

a coil part connected to the coil part through which current flows in the direction of the input current, the coil part being concentrically formed with the coil part and configured such that current flows in a direction opposite to that of the input current,

wherein the coil structure transfers wireless power depending on mutual inductance with respective target coils, relative center positions of which are horizontally different from each other.

44. The coil structure of claim 43, wherein the target coils comprise either a single coil, a relative center position of which is horizontally movable, or multiple coils, relative center positions of which are located at horizontally different positions.

45. The coil structure of claim 43, wherein the coil structure is configured such that a magnetic field in a center of the coil structure is relatively increased to have uniformity in mutual inductance with another coil.

46. The coil structure of claim 43, wherein coils constituting the coil structure are formed using a Printed Circuit Board (PCB) manufacturing process or a semiconductor manufacturing process, and coils formed to be distributed and arranged on multiple layers are connected to each other through via holes.

47. The coil structure of claim 43, wherein respective coil parts of the coil structure are wound in shapes of concentric circles or concentric polygons.

48. The coil structure of claim 43, wherein the coil part through current flows in the direction of the input current includes a coil part concentrically wound multiple times towards a center thereof so that current flows in the direction of the input current.

49. The coil structure of claim 43, wherein the coil part through which the current flows in the direction opposite to that of the input current comprises a coil part in which two or more coils are connected in parallel and wound so that current flows in a direction opposite to that of the input current.

50. The coil structure of claim 49, wherein the coil part in which two or more coils are connected in parallel is wound one or more times.

51. The coil structure of claim 49, wherein the coil part comprises two coils connected in parallel and input current I₀ of the coil part is divided into α

I₀ and (1−

a)I₀ through the two coils, wherein a is any number of which absolute value is equal to or less than 2.

52. A coil structure, comprising:

a coil part through which current flows in a direction of input current applied from a first end of the coil structure, the coil part being disposed between the first end and a second end of the coil structure,

wherein the coil part comprises;

a first coil part concentrically wound one or more times towards a center thereof so that current flows in a direction of the input current; and

a second coil part, a center of which is aligned with that of the first coil part and in which two or more coils are connected in parallel and are concentrically wound so that current flows in the direction of the input current, and

wherein the coil structure transfers wireless power via magnetic coupling with respective target coils, relative center positions of which are horizontally different from each other.

53. The coil structure of claim 52, wherein the second coil part in which two or more coils are connected in parallel and are concentrically wound is wound one or more times.

54. The coil structure of claim 53, wherein the second coil part comprises two coils connected in parallel and input current I₀ of the second coil part is divided into α

I₀ and (1−

α

)I₀ through the two coils, wherein a is any number of which absolute value is equal to or less than 2.

55. The coil structure of claim 52, further comprising a third coil part in which two or more coils are connected in parallel and are concentrically wound so that current flows in a direction opposite to that of the input current.

56. The coil structure of claim 54, wherein the third coil part comprises two coils connected in parallel and input current I₀ of the third coil part is divided into β

I₀ and (1−

β

)I₀ through the two coils, wherein 0 is any number of which absolute value is equal to or less than 2.

57. A wireless power transfer system for transmitting/receiving power between a transmitting coil of a transmitter and a receiving coil of a receiver via magnetic coupling, wherein the transmitting coil or the receiving coil comprises:

a first coil part concentrically wound one or more times towards a center thereof so that current flows in a direction of input current applied from a first end of the transmitting or receiving coil, the first coil part being disposed between the first end and a second end of the transmitting or receiving coil; and

a coil part connected to the first coil part in which the current flows in the direction of the input current, the coil part having a center aligned with that of the first coil part and being concentrically arranged with the first coil part, the coil part being configured such that current flows in a direction opposite to that of the input current;

or

a coil part having a center aligned with that of the first coil part, the coil part being configured such that two or more coils are connected in parallel and are concentrically wound so that current flows in a direction of the input current,

wherein the transmitting coil transmits power to one or more receiving coils, relative center positions of which are horizontally different from each other.

58. The wireless power transfer system of claim 57, wherein uniform mutual inductance within a preset range is obtained between each of the receiving coils and the transmitting coil.

59. The wireless power transfer system of claim 58, wherein the power is transferred because of the uniform mutual inductance, without changing impedance matching regardless of variations of the horizontal position of the transmitter or the receiver.

60. The wireless power transfer system of claim 57, wherein the transmitter comprises means for impedance matching to the transmitting coil between an Alternating Current (AC) source (Vs) and the transmitting coil.

61. The wireless power transfer system of claim 57, wherein the transmitter comprises a source coil connected to the AC source that is a voltage source, current source or power source, and separated from and magnetically coupled to the transmitting coil without being directly connected to the transmitting coil, and performs impedance matching via mutual inductance between the source coil and the transmitting coil.

62. The wireless power transfer system of claim 57, wherein the transmitter comprises a transformer for impedance matching, a primary side of which is connected to an AC source that is a voltage source, current source or power source, and a secondary side of which is connected to the transmitting coil.

63. The wireless power transfer system of claim 57, wherein the transmitter comprises a capacitor for impedance matching connected between the transmitting coil and an AC source that is a voltage source, current source, or a power source.

64. The wireless power transfer system of claim 63, wherein the capacitor is connected in parallel or in series with the transmitting coil.

65. The wireless power transfer system of claim 64, wherein another capacitor is connected in series with the AC source when the capacitor is connected in parallel with the transmitting coil.

66. The wireless power transfer system of claim 64, wherein another capacitor is connected in parallel with the AC source when the capacitor is connected in series with the transmitting coil.

67. The wireless power transfer system of claim 57, wherein the transmitter comprises an inductor for impedance matching connected between the transmitting coil and an AC source that is a voltage source, current source, or power source.

68. The wireless power transfer system of claim 67, wherein the inductor is connected in parallel with the transmitting coil.

69. The wireless power transfer system of claim 68, wherein a capacitor is connected in series between the AC source and the inductor.

70. The wireless power transfer system of claim 57, wherein the receiver comprises means for impedance matching for a load, the means being arranged between the receiving coil and the load.

71. The wireless power transfer system of claim 57, wherein the receiver comprises a load coil connected to a load and magnetically coupled to the receiving coil without being directly connected to the receiving coil, and performs impedance matching by adjusting mutual inductance between the receiving coil and the load coil.

72. The wireless power transfer system of claim 62, wherein the receiver further comprises a capacitor arranged between a first end of the load coil and a first end of the load.

73. The wireless power transfer system of claim 57, wherein the receiver comprises a transformer for impedance matching, a primary side of which is connected to the receiving coil and a secondary side of which is connected to a load.

74. The wireless power transfer system of claim 57, wherein the receiver comprises an inductor or a capacitor for impedance matching connected between a load and the receiving coil.

75. The wireless power transfer system of claim 74, further comprising a capacitor arranged between a first end of the inductor and a first end of the load.

76. The wireless power transfer system of claim 60, wherein the transmitter comprises a sensing circuit for sensing a variation in loads depending on a number of receiving coils, and performs impedance matching by controlling the means for impedance matching so that input impedance is adjusted depending on the variation in the loads sensed by the sensing circuit.