US 2003/0201862 A1 · Inductive power transmission and distribution apparatus using a coaxial transformer

Abstract

A coaxial inductive power transfer and distribution apparatus is disclosed that includes a primary conductor that is stationary and a mobile secondary coil magnetically coupled to the stationary primary conductor to provide an inductive power transfer therebetween. The primary and secondary coils are disposed within a return conductor that is stationary and acts as a return path for current flowing in the primary center conductor. The primary conductor is mechanically connected to the interior surface of the return conductor to ensure the position stability of the primary conductor with respect to the secondary coil. The return conductor also includes an air gap in which a support member for the mobile secondary coil and structure is disposed within. The mobile secondary coil and structure includes a toroidal core composed of a high permeability material that is coaxially disposed about, and spaced apart from, the primary conductor. A multi-turn coil is radially disposed about the high permeability toroidal core such that magnetic flux produced by a current flowing in the center conductor is coupled to the coil. The secondary structure includes a support element coaxially disposed about the high permeability toroidal core and the multi-turn coil. The support member extends through the air gap in the return conductor to the exterior of the return conductor, where it may be coupled to an electric vehicle. The low inductance of the primary conductor allows for low voltages to be used to power the vehicle electrically coupled to the mobile secondary coil and mechanically coupled to the mobile secondary structure.

Claims17

Dependent claims

An inductive power transfer apparatus for transferring power from a power source comprising:

a primary conductor extending in the longitudinal direction, the primary conductor having a first end and a second end;
a return conductor surrounding the primary conductor and spaced apart therefrom;
a first support element configured and arranged to secure the center conductor in place;
the primary conductor electrically coupled to the power source and receiving power therefrom and the primary conductor further electrically coupled to the return conductor, the return conductor being electrically coupled to the power source to provide a return path thereto;
a moveable secondary including a high permeability toroidal core coaxially disposed about the center conductor and spaced apart therefrom forming a first air gap, the toroidal core including a second air gap, the first support element disposed within the second air gap, the secondary further including a multi-turn coil disposed radially about the high permeability toroidal core;
a second support element configured and arranged to support the high permeability core and the multi-turn coil;
and
whereby an alternating current imposed upon the primary conductor by the power source induces a voltage in the plurality of secondary coils.

5 more elements

A system for the inductive power transfer and distribution for an electric vehicle moveable on a track comprising:

a voltage source having a predetermined frequency and amplitude;
a power transformer primary coil coupled to the voltage source;
a power transformer secondary coil, magnetically coupled to the power transformer primary coil and providing a secondary voltage that is a function of the amplitude of the voltage source and the turns ratio between the power transformer primary coil and the power transformer secondary coil;
a capacitor coupled across the voltage source;
a plurality of transformer primary coils each having a first number of turns, the plurality of transformer primary coils connected in series with one another and with the power transformer secondary coil, wherein the plurality of transformer primary coils and the capacitor form a resonant circuit that is resonant substantially at the predetermined frequency of the voltage source;
a plurality of transformer secondary coils each having a second number of turns, each magnetically coupled to a corresponding one of the plurality of transformer primary coils, each of the plurality of transformer secondary coils providing a secondary voltage having the predetermined frequency and a magnitude that is a function of the amplitude of the voltage source and the first and second number of turns;
and
a plurality of primary center conductors each coupled to a corresponding one of the plurality of transformer secondary windings, wherein the primary center conductors are oriented and positioned such that as the vehicle moves on the track, a secondary system mounted on the electric vehicle engages the primary center conductor receiving inductively transferred power therefrom.

5 more elements

Dependencies are inferred from the claim text.

Inductive power transmission and distribution apparatus using a coaxial transformer

Life of this patent

Inductive power transmission and distribution apparatus using a coaxial transformer

Life of this patent

Abstract

Claims17