Contactless electricity-supplying device

• US 8,716,976 B2
• Filed: 05/14/2010
• Issued: 05/06/2014
• Est. Priority Date: 05/14/2009
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Kai, Toshihiro, Throngnumchai, Kraisorn, Hayami, Yasuaki, Minagawa, Yusuke, Maikawa, Kengo
• Primary Examiner(s): WILLIAMS, ARUN C
• Application Number:
  US13/320,099
• Publication Number:
  US 20120056580A1
• Time in Patent Office: 1,453 Days
• Field of Search: 320/108
• US Class Current: 320/108
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

A contactless electricity-supplying device (20) includes a secondary winding (201) to which electric power is supplied from a primary winding (101), by an AC power supply (6). The impedance characteristic (Z) of Z₁ in regard to the frequency has a local maximum (Z_MAX) near the frequency (f₀) of the fundamental wave component of aforementioned AC power supply (6); and the impedance characteristic (Z) of Z₂ in regard to the frequency has the aforementioned frequency (f₀) of the fundamental wave component to be between, a frequency (f_MAX) that has its local maximum (Z_MAX) nearest to aforementioned frequency (f₀) of the fundamental wave component, and a frequency (f_MIN) that has its local minimum (Z_Min) nearest to the frequency (f₀) of the fundamental wave component. Z₁ indicates that the coupling coefficient (k) between aforementioned primary winding (101) and aforementioned secondary winding (201) is a prescribed value (0.3), and that it is an impedance of just the primary side (Z₁) as seen from the output side of aforementioned AC power supply (6); and Z₂ indicates that the coupling coefficient (k) between aforementioned primary winding (101) and aforementioned secondary winding (201) is the aforementioned prescribed value (0.3), and that it is an impedance of just the secondary side (Z₂) as seen from the side of a load (72) to be connected to aforementioned secondary winding (201).

Claims

1. A contactless electricity-supplying device comprising:

a secondary winding to which an electric power is supplied from a primary winding by an alternating current power supply;

an impedance characteristic of Z₁ relative to a frequency has a maximum in a vicinity of a frequency of a fundamental wave component of the alternating current power supply,

an impedance characteristic of Z₂ relative to the frequency has the frequency of the fundamental wave component between, a frequency that has a maximum nearest to the frequency of the fundamental wave component, and a frequency that has a minimum nearest to the frequency of the fundamental wave component,

wherein

Z₁ shows that a coupling coefficient between the primary winding and the secondary winding is a certain value, and that the Z₁ is an impedance of only a primary side when the Z₁ is viewed from an output side of the alternating current power supply, and

Z₂ shows that the coupling coefficient between the primary winding and the secondary winding is the certain value, and that the Z₂ is an impedance of only a secondary side when the Z₂ is viewed from a load side connected to the secondary winding.

2. The contactless electricity-supplying device according to claim 1 wherein, with the coupling coefficient between the primary winding and the secondary winding being the certain value, a phase characteristic of an impedance relative to the frequency viewed from the output side of the alternating current power supply is close to zero relative to the frequency of the fundamental wave component.

3. The contactless electricity-supplying device according to claim 1 wherein, with the coupling coefficient between the primary winding and the secondary winding being the certain value, a phase characteristic of an impedance relative to the frequency viewed from the output side of the alternating current power supply has such a characteristic that when the coupling coefficient is changed in a certain range relative to the certain value, a phase relative to the frequency of the fundamental wave component fluctuates at a value close to zero.

4. The contactless electricity-supplying device according to claim 1 wherein the impedance characteristic of the Z₁ further has an extreme value other than the maximum.

5. The contactless electricity-supplying device according to claim 1 wherein the impedance characteristic of the Z₂ further has an extreme value other than the maximum and the minimum.

6. The contactless electricity-supplying device according to claim 1 wherein

the phase characteristic of the Z₁ relative to the frequency has such a characteristic that a phase inclination relative to the frequency is diverged in an area in the vicinity of the frequency of the fundamental wave component,

the phase characteristic of the Z₂ relative to the frequency has such a characteristic as to have at least two points on a frequency axis at which points the phase inclination relative to the frequency is diverged,

between the two points, the phase characteristic has a portion which is parallel to the frequency axis, and

the frequency of the fundamental wave component is disposed between the two points.

7. The contactless electricity-supplying device according to claim 1 wherein a first capacitor is connected in parallel to the primary winding.

8. The contactless electricity-supplying device according to claim 7 wherein a first inductor is connected in series to the primary winding and the first capacitor.

9. The contactless electricity-supplying device according to claim 7 wherein a second capacitor is connected in series to a parallel circuit composed of the primary winding and the first capacitor.

10. The contactless electricity-supplying device according to claim 7 wherein a first inductor is connected to a first end of a parallel circuit composed of the primary winding and the first capacitor and a second capacitor is connected to a second end of the parallel circuit composed of the primary winding and the first capacitor.

11. The contactless electricity-supplying device according to claim 1 wherein a fourth capacitor is connected in series to a parallel circuit composed of the secondary winding and a third capacitor.

12. The contactless electricity-supplying device according to claim 1 wherein

a fifth capacitor is connected in series to the secondary winding, and

a third capacitor is connected in parallel to a series circuit composed of the secondary winding and the fifth capacitor.

13. The contactless electricity-supplying device according claim 12 wherein a sixth capacitor is connected to an area between a connection point between the secondary winding and the fifth capacitor and a second end of the secondary winding.

14. The contactless electricity-supplying device according claim 12 wherein a fourth capacitor is connected to a connection point between the fifth capacitor and the third capacitor.

15. The contactless electricity-supplying device according to claim 1 wherein

a fifth capacitor is connected in series to the secondary winding, and

a third inductor is connected in parallel to a series circuit composed of the secondary winding and the fifth capacitor.

16. The contactless electricity-supplying device according to claim 15 wherein a fourth capacitor is connected to a connection point between the fifth capacitor and the third inductor.

17. The contactless electricity-supplying device according to claim 1 wherein a fourth inductor is connected in series to the secondary winding and a third capacitor is connected in parallel to a series circuit composed of the secondary winding and the fourth inductor.

18. A vehicle comprising:

the contactless electricity-supplying device according to claim 1,

wherein the secondary winding is mounted to the vehicle, and a coupling coefficient between the primary winding and the secondary winding is set in accordance with a parking position of the vehicle.

19. The contactless electricity-supplying device according to claim 1 wherein

a first capacitor is connected in parallel to the primary winding,

a fourth capacitor is connected in series to a parallel circuit composed of the secondary winding and a third capacitor,

the frequency of the fundamental wave component is set in a vicinity of a resonant frequency of the Z₁, and

the frequency of the fundamental wave component is set between a first resonant frequency of the Z₂ and a second resonant frequency of the Z₂, the second resonant frequency being higher than the first resonant frequency.

20. The contactless electricity-supplying device according to claim 1 wherein

a first capacitor is connected in parallel to the primary winding and a fourth capacitor is connected in series to a parallel circuit composed of the secondary winding and a third capacitor, satisfying C_1p=1/(L₁(2π

f₀)²) and C_2p<

(L₁/L₂)C_1p<

(C_2s+C_2p), where C_1p denotes a capacitance of the first capacitor, L₁ denotes an inductance of the primary winding, f₀ denotes the frequency of the fundamental wave component, C_2p denotes a capacitance of the third capacitor, C_2s denotes a capacitance of the fourth capacitor and L₂ denotes an inductance of the secondary winding.

21. The contactless electricity-supplying device according to claim 1 wherein

a first capacitor is connected in parallel to the primary winding,

a fourth capacitor is connected in series to a parallel circuit composed of the secondary winding and a third capacitor,

with the coupling coefficient between the primary winding and the secondary winding being the certain value, when the impedance characteristic viewed from the output side of the alternating current power supply is denoted by a complex plane, a first pole that is nearest to an imaginary axis moves away from the imaginary as the coupling coefficient between the primary winding and the secondary winding increases, and a second pole that is second nearest to the imaginary axis approaches the first pole as the coupling coefficient increases.

22. The contactless electricity-supplying device according to claim 1 wherein

a supply voltage supplied from the alternating current power supply to the primary winding at a certain period includes, per period, a plurality of positive voltage output periods and a plurality of negative voltage output periods, a first rest period disposed between the plurality of positive voltage output periods and a second rest period disposed between the plurality of negative voltage output periods.

23. The contactless electricity-supplying device according to claim 22 wherein the first rest period and the second rest period are the same in time length.

24. The contactless electricity-supplying device according to claim 22 wherein, per period, the supply voltage has each of the first rest period and the second rest period one in number.

25. The contactless electricity-supplying device according to claim 22 wherein when T denotes the certain period, t_b1 denotes the first rest period, t_b2 denotes the second rest period and D denotes a duty ratio, t_b1=0.015·

T/D or t_b2=0.015·

T/D is satisfied.