Primary inductive pathway

• US 5,619,078 A
• Filed: 11/10/1994
• Issued: 04/08/1997
• Est. Priority Date: 05/10/1992
• Status: Expired due to Term

• Current Assignee: Auckland UniServices Limited (Auckland University), Daifuku Company Limited
• Original Assignee: John T. Boys, Shuzo Nishino
• Inventors: Boys, John T., Nishino, Shuzo
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): PALADINI, ALBERT WILLIAM
• Application Number:
  US08/335,710
• Time in Patent Office: 880 Days
• Field of Search: 307/85, 191/10, 191/6, 191/12 R, 104/23, 104/288, 104/298, 104/287, 104/292
• US Class Current: 307/85
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H04B 5/22 Capacitive coupling
• 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 primary inductive track or path 450 for a resonant inductive power distribution system is made up from a number of modules 453, each supplied as a pre-built and substantially pre-tuned segment of the track. These modules have more than one capacitor 456, 457 and more than one inductance 458, 459 (generally, the inductance is the intrinsic inductance of the length of track) and each capacitor and adjacent inductor is capable of resonating at its own native frequency. A zero-inductance cable 452, carrying a small fraction of the circulating resonant current (comprising a mis-match or an error current), directly connects the capacitors at poles having equal polarity and tends to constrain the system limiting possible frequencies of resonance.

Claims

1. A primary inductive pathway for a resonant inductive power distribution system operating at a system resonant frequency, said pathway being connected to a power supply and having two spaced conductors terminated by a bridging element and forming with said power supply a closed loop, wherein said primary inductive pathway comprises at least two primary conductor modules, each primary conductor module having a resonant frequency compatible with the system resonant frequency, each said primary conductor module comprising a first conductor and a second conductor spaced apart from one another, each conductor having a first connector and a second connector, each module having at least one capacitor;

each module being capable of connection to adjoining conductors within adjacent modules or to a bridging element at one end of the pathway, so that a number of modules can be joined together to form a longer pathway, through the length of which an effective amount of inductive power can, during use, be propagated.

2. A primary inductive pathway for a resonant inductive power distribution system as claimed in claim 1, wherein said at least one capacitor is connected in series with each conductor of said modules.

3. A primary conductive pathway for a resonant inductive power distribution system as claimed in claim 1, wherein a first of said modules has one capacitor in series with the first conductor of the first module, and an adjacent complementary module connected to the first module has one capacitor in series with the second conductor of a second module.

4. A primary inductive pathway for a resonant inductive power distribution system as claimed in claim 2, wherein repeating pairs of said first and second modules are connected together.

5. A primary inductive pathway for a resonant inductive power distribution system as claimed in claim 1, wherein said pathway has at least two bypass joining points which, in use, have equal or similar phase and magnitude so that the tied-together points are held more closely to the same phase and magnitude.

6. A primary inductive pathway for a resonant inductive power distribution system as claimed in claim 5, wherein the bypass comprises a zero inductance cable.

7. A primary inductive pathway for a resonant inductive power distribution system as claimed in claim 5, wherein each module includes a capacitor across its first connectors and a zero inductance cable joining the first connector of the first conductor of a first module to the first connector of the second conductor of an adjacent module;

and joining the first connector of the second conductor of said first module to the first connector of the first conductor of said adjacent module.

8. A primary inductive pathway for a resonant inductive power distribution system as claimed in claim 1, further comprising loop energizing means comprising controllable switching means connected between two electrical connections at an origin of the loop, for providing a bypass route for high-frequency resonant current applied to the two electrical connections.

9. A primary inductive pathway for a resonant inductive power distribution system as claimed in claim 1, wherein said first conductor and said second conductor of each of said at least two primary conductor modules are mounted, in a parallel, spaced-apart configuration and thereby form an open-ended, elongated loop having an electrical connection at each end of each conductor, so that a chain of adjoining modules may be joined together in series and energized as a whole by a resonant power supply.

10. A primary conductive pathway as claimed in claim 1, wherein each of said at least two primary conductor modules includes a branch line, each branch line being connected to a main trunk line, said pathway further comprising means for shorting and bypassing a selected branch line to de-energize a corresponding module.

11. A primary inductive pathway as claimed in claim 10, wherein each of said at least two primary conductor modules comprises associated warning means powered directly or indirectly from current flowing within each module in order to indicate when each module is energized.

12. A primary inductive pathway as claimed in claim 1, comprising ferro-magnetic elements close to said pathway, wherein said ferro-magnetic elements are shielded from the magnetic fields by a conductive sheath.

13. A primary inductive pathway for a resonant inductive power distribution system operating at a system resonant frequency, said pathway being adapted to be connected to a power supply and having a first conductor and a second conductor spaced apart from one another, wherein a first and second end of each conductor are brought close together, said pathway further including a capacitor, and a linkage;

each conductor having a first end and a second end, a connector at a first end being connected to a power supply, the capacitor being connected across the second ends of the first and second conductor, the linkage comprising a connection between the first end of the first conductor and the second end of the second conductor, and a connection between the first end of the second conductor and the second end of the first conductor, whereby, in use, an effective amount of inductive power can be propagated along the length of the pathway.