BATTERY CHARGING PAD EMPLOYING MAGNETIC INDUCTION

• US 20100315038A1
• Filed: 06/14/2010
• Published: 12/16/2010
• Est. Priority Date: 06/16/2009
• Status: Active Grant

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: TERAO, Kyozo, TOYA, Shoichi
• Granted Patent: US 8,362,744 B2
• Time in Patent Office: Days
• US Class Current: 320/108
• 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 2310/22 The load being a portable electronic device
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0045 concerning the insertion or the connection of the batteries

Abstract

The battery charging pad comprises a moving mechanism 13 that moves the transmitting coil 11, and a position detection controller 14 that detects the position of a device housing a battery 50 and controls the moving mechanism to move the transmitting coil in close proximity to a receiving coil 51. Pulse signals are supplied to a plurality of position detection coils 30 from a pulse generator 31, and the echo signals are a result of coil excitation by the pulse signals. The battery charging pad position detection controller 14 detects the position of the receiving coil 51 and moves the transmitting coil 11 in close proximity to the receiving coil 51, and the position detection controller 14 detects the position of the transmitting coil 11 and moves the transmitting coil 11 to the reference position, or it moves the transmitting coil 11 in close proximity to the receiving coil 51.

Claims

1. A battery charging pad that transmits power from a transmitting coil to a magnetically coupled receiving coil to charge a battery housed in a device housing a battery comprising:

a transmitting coil that is put in close proximity to the receiving coil in the device housing a battery and transmits electrical power to the receiving coil;

a case that houses the transmitting coil and has a top plate where a device housing a battery is placed;

a moving mechanism housed in the case to move the transmitting coil in close proximity to the receiving coil; and

a position detection controller that detects the position of a device housing a battery placed on the top plate and controls the moving mechanism to move the transmitting coil in close proximity to the receiving coil in the device housing a battery, the position detection controller comprising;

a plurality of position detection coils fixed to the inside surface of the top plate;

a pulse generator that supplies pulse signals to the position detection coils;

a receiving circuit that receives echo signals output from the receiving coil and transmitting coil to the position detection coils as a result of excitation by pulse signals supplied from the pulse generator to the position detection coils; and

a discrimination circuit that determines the position of the receiving coil and the transmitting coil from the echo signals received by the receiving circuit,

wherein the position detection controller detects the position of the receiving coil and transmitting coil and controls the moving mechanism to move the transmitting coil in close proximity to the receiving coil.

2. The battery charging pad as cited in claim 1 wherein the position detection controller detects transmitting coil position and moves the transmitting coil to the X-axis direction and Y-axis direction origin (0, 0 point).

3. The battery charging pad as cited in claim 2 wherein the position detection controller detects the position of the transmitting coil, and from the detected transmitting coil position, computes the distances in the X-axis direction and Y-axis direction to move the transmitting coil to the origin reference point;

and the position detection controller controls the moving mechanism to move the transmitting coil by the computed distances in the X-axis direction and Y-axis direction towards the origin reference point.

4. The battery charging pad as cited in claim 3 wherein the moving mechanism implements movement distances larger than the computed distances to move the transmitting coil to the origin reference point absorbing moving mechanism slippage at the origin.

5. The battery charging pad as cited in claim 3 wherein the moving mechanism is provided with servo motors to move the transmitting coil;

the transmitting coil is moved to the origin via the servo motors; and

after the moving mechanism servo motors rotate to move the transmitting coil from the detected position to the origin reference point, torque is further applied for a given time in a direction to move the transmitting coil toward the origin reference point.

6. The battery charging pad as cited in claim 1 wherein the position detection controller detects the relative position of the transmitting coil with respect to the receiving coil and moves the transmitting coil into close proximity with the receiving coil.

7. The battery charging pad as cited in claim 1 wherein the position detection coils are made up of a plurality of rows of coils, and those position detection coils are fixed at given intervals to the inside surface of the top plate;

further, the position detection coils are provided with a plurality of X-axis detection coils that detect transmitting coil and receiving coil position in the X-axis direction, and a plurality of Y-axis detection coils that detect position in the Y-axis direction.

8. The battery charging pad as cited in claim 7 wherein the plurality of X-axis detection coils are shaped as long narrow loops extending in the Y-axis direction and fixed to the inside surface of the top plate at given intervals;

and the plurality of Y-axis detection coils are shaped as long narrow loops extending in the X-axis direction and fixed to the inside surface of the top plate at given intervals.

9. The battery charging pad as cited in claim 8 wherein the interval (d) between adjacent X-axis detection coils is smaller than the outside diameter (D) of the receiving coil and smaller than the outside diameter (W) of the transmitting coil;

and the interval (d) between adjacent Y-axis detection coils is smaller than the outside diameter (D) of the receiving coil and smaller than the outside diameter (W) of the transmitting coil.

10. The battery charging pad as cited in claim 1 wherein a switching circuit is provided between the transmitting coil and the AC power source;

this switching circuit connects the transmitting coil to the AC power source to supply AC power to the transmitting coil from the AC power source; and

the switching circuit puts both sides of the output at ground potential to detect transmitting coil position.

11. The battery charging pad as cited in claim 10 wherein a capacitor is provided that connects in parallel with the transmitting coil to form a parallel resonant circuit;

and the switching circuit grounds both sides of the output to form the parallel resonant circuit with the capacitor and transmitting coil for detection of the transmitting coil position.

12. The battery charging pad as cited in claim 10 wherein the switching circuit is provided with an input circuit that grounds both sides of the output, and both sides of the switching circuit output are put at ground potential by a control signal input from the input circuit.

13. The battery charging pad as cited in claim 12 wherein the switching circuit employs a full-bridge output circuit connected to the output-side of the AC power source, and the AC power source has the full-bridge output circuit connected to the output-side of an oscillator circuit to supply AC power to the transmitting coil.

14. The battery charging pad as cited in claim 1 wherein the AC power source is provided with an oscillator circuit, and the oscillator circuit AC is amplified by the full-bridge output circuit and supplied to the transmitting coil.

15. The battery charging pad as cited in claim 10 wherein the switching circuit employs a full-bridge output circuit connected to the output-side of the AC power source;

a voltage signal is input to the full-bridge output circuit to ground the output side; and

both sides of the switching circuit output are put at ground potential to detect transmitting coil position.

16. The battery charging pad as cited in claim 1 wherein a capacitor connected in parallel with the transmitting coil is provided to form a parallel resonant circuit;

the capacitance C1 of this capacitor is made a different value than the capacitance C2 of the capacitor connected in parallel with the receiving coil to form a parallel resonant circuit in the device housing a battery; and

the position detection controller distinguishes the position of the transmitting coil and the receiving coil from the different delay times of the echo signals output to the position detection coils from the transmitting coil and the receiving coil.

17. The battery charging pad as cited in claim 16 wherein a capacitor connected in parallel with the transmitting coil is provided to form a parallel resonant circuit;

the capacitance C1 of this capacitor is made larger than the capacitance C2 of the capacitor connected in parallel with the receiving coil to form a parallel resonant circuit in the device housing a battery; and

the position detection controller distinguishes the position of the transmitting coil and the receiving coil from the different delay times of the echo signals output to the position detection coils from the transmitting coil and the receiving coil.

18. The battery charging pad as cited in claim 1 wherein the position detection controller is provided with a first position detection controller that detects the position of the transmitting coil and the position of the receiving coil, and a second position detection controller that detects the position of the receiving coil with high precision;

and the first position detection controller is provided with position detection coils.

19. The battery charging pad as cited in claim 18 wherein the second position detection controller detects receiving coil position by either the oscillating frequency of the AC power source, transmitting coil voltage, AC power source power consumption, or receiving coil current.