Contactless power feeding apparatus

• US 9,369,181 B2
• Filed: 09/29/2011
• Issued: 06/14/2016
• Est. Priority Date: 11/12/2010
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Kai, Toshihiro, Kraisorn, Throngnumchai, Minagawa, Yusuke
• Primary Examiner(s): Fleming, Fritz M
• Assistant Examiner(s): Parries, Dru
• Application Number:
  US13/884,438
• Publication Number:
  US 20130221758A1
• Time in Patent Office: 1,720 Days
• Field of Search: 307/104
• US Class Current: 1/1
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02M 3/01 Resonant DC/DC converters
• CPC Class Codes: H02M 3/33573 Full-bridge at primary side of an isolation transformer
• CPC Class Codes: H04B 5/266 One coil at each side, e.g. with primary and secondary coils
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

A contactless power feeding apparatus includes a secondary winding to which power is supplied from a primary winding by an AC power supply. An impedance absolute-value characteristic of Z1 has a frequency of a fundamental wave component to be between a frequency where a local maximum exists and that is nearest to the frequency of the fundamental wave component, and a frequency where a local minimum exists and that is nearest to the frequency of the fundamental wave component. An impedance absolute-value characteristic of Z2 has the frequency of the fundamental wave component to be between a frequency where the local maximum exists and that is nearest to the frequency of the fundamental wave component, and a frequency where the local minimum exists and that is nearest to the frequency of the fundamental wave component.

Claims

1. A contactless power feeding apparatus comprising a secondary winding to which power is supplied from a primary winding by an AC power supply, wherein

an impedance absolute-value characteristic of Z1 with respect to a frequency has a frequency of a fundamental wave component of the AC power supply to be between a frequency where a local maximum exists and that is nearest to the frequency of the fundamental wave component of the AC power supply, and a frequency where a local minimum exists and that is nearest to the frequency of the fundamental wave component, and

an impedance absolute-value characteristic of Z2 with respect to the frequency has the frequency of the fundamental wave component to be between a frequency where the local maximum exists and that is nearest to the frequency of the fundamental wave component of the AC power supply, and a frequency where the local minimum exists and that is nearest to the frequency of the fundamental wave component,

where Z1 indicates the impedance of just a primary side when viewed from an output side of the AC power supply, and Z2 indicates an impedance of just a secondary side when viewed from a side of a load to be connected to the secondary winding.

2. The contactless power feeding apparatus according to claim 1, wherein a first capacitor is connected in series with the primary winding, a second capacitor is connected in parallel with the primary winding, a third capacitor is connected in series with the secondary winding, and a fourth capacitor is connected in parallel with the secondary winding, and the following relationships are satisfied:

f_1A<

f₀<

f_1B; and

f_2A<

f₀<

f_2B, provided that the following equations are satisfied;

3. The contactless power feeding apparatus according to claim 2, wherein the following relationship is satisfied:

f_1A≦

f_2A<

f₀<

f_2B≦

f_1B.

4. The contactless power feeding apparatus according to claim 1, wherein an absolute value of Z_in with respect to the frequency of the fundamental wave component is set according to a value of impedance of the AC power supply, where Z_in indicates an input impedance of a power feeding circuit including the primary winding and the secondary winding when viewed from the output side of the AC power supply.

5. The contactless power feeding apparatus according to claim 1, wherein, when a coefficient of coupling between the primary winding and the secondary winding varies within a range of 0.01 to 0.5 inclusive, an absolute value of Z_in with respect to the frequency of the fundamental wave component varies in the vicinity of a value of impedance of the AC power supply, where Z_in indicates an input impedance of the power feeding circuit including the primary winding and the secondary winding when viewed from an output side of the AC power supply.

6. The contactless power feeding apparatus according to claim 1, wherein a first capacitor is connected in series with the primary winding, a second capacitor is connected in parallel with the primary winding, a third capacitor is connected in series with the secondary winding, and a fourth capacitor is connected in parallel with the secondary winding, and, when a characteristic of the input impedance of the power feeding circuit including the primary winding and the secondary winding when viewed from the output side of the AC power supply is represented in a complex plane, a first pole and a zero point that are nearest to an imaginary axis make loci which are symmetric with respect to a value corresponding to the frequency of the fundamental wave component, on the imaginary axis, as a coefficient of coupling between the primary winding and the secondary winding increases, and a second pole that is the second nearest to the imaginary axis approaches the first pole as the coupling coefficient increases.

7. The contactless power feeding apparatus according to claim 1, wherein a first capacitor is connected in series with the primary winding, a second capacitor is connected in parallel with the primary winding, a third capacitor is connected in series with the secondary winding, and a fourth capacitor is connected in parallel with the secondary winding, and a difference in frequency between f_1A and f_1B in an input impedance of the power feeding circuit including the primary winding and the secondary winding when viewed from an output side of the AC power supply is set according to the impedance of the AC power supply, where the following equations are satisfied: