Inductive energy transmission system

Abstract

An inductive energy transmission system including: a primary coil connectible to an electrical useful voltage source, the primary coil being connected to a first capacitor, the first capacitor being connected to a local ground potential of the energy transmission system; and a secondary coil inductively coupled to the primary coil; wherein a second capacitor is situated between the primary coil and the local ground potential of the energy transmission system.

Claims

1. An inductive energy transmission system, comprising: a primary coil that is connectible to an electrical useful voltage source, the primary coil being connected to a first capacitor, the first capacitor being connected to a local ground potential of the energy transmission system; and a secondary coil inductively coupled to the primary coil; wherein a second capacitor is between the primary coil and the local ground potential of the energy transmission system.

2. The inductive energy transmission system of claim 1, wherein a first electrode of the second capacitor is formed by the primary coil and a second electrode of the second capacitor is connected to the local ground potential.

3. The inductive energy transmission system of claim 1, wherein the second electrode of the second capacitor is configured in layers, a conductive layer being covered on opposite surfaces by respectively one insulating layer.

4. The inductive energy transmission system of claim 3, wherein the conductive layer of the second capacitor is configured in a fleece-like manner from a carbon material.

5. The inductive energy transmission system of claim 3, wherein the conductive layer is configured to be woven or pressed.

6. The inductive energy transmission system of claim 3, wherein the conductive layer is connected to the local ground potential by conductive reinforcement elements.

7. The inductive energy transmission system of claim 1, wherein the second capacitor has a capacitance value that is at least approximately twice as great as a parasitic ground capacitance of the inductive energy transmission system.

8. The inductive energy transmission system of claim 1, wherein the second capacitor has a capacitance value that is at least approximately six times to approximately ten times as great as a parasitic ground capacitance of the inductive energy transmission system.

9. The inductive energy transmission system of claim 1, wherein the second capacitor has a capacitance value that is at least approximately three times to approximately five times as great as a parasitic ground capacitance of the inductive energy transmission system.

10. A method for manufacturing an inductive energy transmission system, the method comprising: providing a primary coil; connecting the primary coil to a first capacitor; connecting the first capacitor to a local ground potential of the energy transmission system; providing a secondary coil; and providing a second electrode of a second capacitor, the second electrode of the second capacitor being connected to the local ground potential.

11. The method of claim 10, wherein the second electrode is configured in layered fashion having a conductive layer and respectively one insulating layer on opposite surfaces of the conductive layer.

12. The method of claim 11, wherein the conductive layer is configured as a fleece-like fabric made of a carbon material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a basic block diagram of a conventional inductive energy transmission system.

(2) FIG. 2 shows a specific embodiment of an inductive energy transmission system according to the invention.

(3) FIG. 3 shows a simplified representation of a possible implementation of a second electrode of the bypass capacitor.

(4) FIG. 4 shows a basic sequence of one specific embodiment of the method according to the invention.

DETAILED DESCRIPTION

(5) As an effective noise suppression measure, the present invention provides for the insertion of a bypass capacitor in the form of a second capacitor 50 into the primary circuit so as in this manner to keep the noises within the primary circuit. Second capacitor 50 conducts the noises directly back to the noise voltage source U.sub.S and thus effectively prevents an unwanted indirect coupling path of the noises. In order to achieve a significant bypass effect by way of second capacitor 50, its capacitance should be approximately twice, more particularly approximately three to approximately five times, particularly approximately six to approximately ten times as great as a ground capacitance of the entire system formed from parasitic ground capacitances 12, 13, 14.

(6) FIG. 2 shows a current path of the noise following the insertion of the bypass capacitor fundamentally as a closed circuit represented by a dashed line. The current path in effect forms a closed path via the useful voltage source U.sub.Ex, the noise voltage source U.sub.S, the primary coil 10 and second capacitor 50. The current path thus essentially no longer runs via measuring resistor 40, which allows the measurable noise to be reduced significantly.

(7) In order to implement the bypass capacitor, a technical implementation of a second electrode 50a is required, after the first electrode of the bypass capacitor is formed by the winding of primary coil 10. For this purpose, it is provided to mount a conductive layer 90 in direct proximity to primary winding 10. It is furthermore important to design the capacitance of the bypass capacitor to be as high as possible, two essential factors that may influence said capacity being a maximization of the electrode surface and a minimization of the distance of the two electrodes with respect to each other.

(8) FIG. 3 shows in a greatly simplified manner a fundamental technical specific embodiment of a second electrode 50a of second capacitor 50. The present invention may provide for two layers of insulating foils to be situated one upon the other, between which a conductive graphite or carbon layer is situated. The arrangement layered in this manner thus forms the second electrode 50a, which is conductively connected to the local ground terminal of first capacitor 15. In combination with the primary electrode of primary coil 10, the noise suppressing bypass capacitor is implemented in this manner.

(9) In principle, any conductive material may be used for conductive layer 90 of electrode 50a with the exception of metallic, in particular ferromagnetic material since this material would produce unwanted eddy current and hysteresis losses.

(10) Test series have shown that using a conductive layer or electrode in the form of a graphite or carbon layer as conductive layer 90 provides the best results for an optimized noise-suppression effect of second capacitor 50. For this purpose, the graphite layer may be developed advantageously by a lacquer. Particularly advantageously, the graphite layer is configured as a carbon fiber weave or a fleece-like fiber fabric, it being possible for conductive layer 90 to be woven or pressed in a fleece-like manner as a fleece-like carbon material. The second electrode 50a of the bypass capacitor formed in this manner is connected in an electrically conductive manner to a fixed reference point, normally the local ground potential 16 of first capacitor 15 of inductive energy transmission system 100.

(11) As a mechanical reinforcement of conductive layer 90, it is possible to use electrically conductive reinforcement rings 91, which are made of aluminum or copper and which are provided for a mechanical reinforcement of conductive layer 90 and an improved electrical contact between electrode 50a and ground potential 16.

(12) FIG. 4 shows in principle a sequence of a specific embodiment of the method of the present invention.

(13) A primary coil 10 is provided in a first step 200.

(14) In a second step 210, primary coil 10 is connected to a first capacitor 15.

(15) In a third step 220, first capacitor 15 is connected to a local ground potential 16 of energy transmission system 100.

(16) In a fourth step 230, a secondary coil 20 is provided.

(17) Finally, in a fifth step 240, a second electrode 50a of a second capacitor 50 is provided, second electrode 50a of second capacitor 50 being connected to local ground potential 16.

(18) Advantageously, inductive energy transmission system 100 may be used in any technical systems in which contactless inductive charging occurs, for example in an electric toothbrush, an electric car etc.

(19) In summary, the present invention provides an improved inductive energy transmission system that advantageously returns electromagnetic noises essentially to the source of the noise and thereby optimizes the efficiency of the inductive energy transmission system.

(20) One skilled in the art, in proceeding, will implement specific embodiments of the present invention that are not described, or only partially described, without deviating from the core of the present invention.