TRANSFORMER

Abstract

A transformer has a magnetic core, a coil which runs around a core section of the magnetic core, and a filling layer which is arranged between the core section and the coil. The filling layer, which may fill a gap formed between the core and the coil completely, is produced from a magnetizable material.

Claims

1-10. (canceled)

11. A transformer, comprising: a magnetic core; a coil extending around a core section of said magnetic core; and a filling layer formed of a magnetizable material arranged between said core section and said coil.

12. The transformer according to claim 11, wherein said core section and said coil are disposed to form a gap therebetween, and said filling layer completely fills said gap between said core section and said coil.

13. The transformer according to claim 11, wherein said filling layer is made of a paramagnetic material.

14. The transformer according to claim 11, wherein said filling layer has a higher relative permeability than air.

15. The transformer according to claim 11, wherein said filling layer is made of a soft magnetic material.

16. The transformer according to claim 11, wherein said filling layer is made of a soft magnetic composite material.

17. The transformer according to claim 11, wherein said filling layer is produced by pressing and sintering a soft magnetic powder composite material.

18. The transformer according to claim 11, wherein said filling layer has an outer surface distal from said core section, and said outer surface has a shape of a cylinder with a smooth trajectory.

19. The transformer according to claim 18, wherein said trajectory is oval.

20. The transformer according to claim 19, wherein said trajectory is circular.

21. The transformer according to claim 11, wherein said magnetic core is formed of a plurality of electrical sheets.

Description

[0021] FIG. 1 a cross-sectional representation of a magnetic core of an exemplary embodiment of a transformer,

[0022] FIG. 2 a perspective sectional view of an exemplary embodiment of a transformer.

[0023] Corresponding parts are provided with the same reference symbols in the figures.

[0024] FIG. 1 (FIG. 1) shows a cross-sectional illustration of a magnetic core 1 of an exemplary embodiment of a transformer 3 according to the invention (see FIG. 2). The magnetic core 1 is made from electrical steel by laminating electrical steel sheet layers (not shown in detail) and joining them together in an electrically insulated manner. The electrical steel sheet layers are designed and arranged with different widths in such a way that the cross section of the magnetic core 1 approximates a circular area. Due to the layering of the electrical steel sheet the surface of the magnetic core 1 has edges 5 and steps 7.

[0025] FIG. 2 (FIG. 2) shows a perspective sectional illustration of an exemplary embodiment of a transformer 3 according to the invention.

[0026] The transformer 3 comprises a magnetic core 1, a coil 9 running around a core section of the magnetic core 1, and a magnetizable filling layer 11 arranged between the core section and the coil 9. The magnetic core 1 is designed like the magnetic core 1 described with reference to FIG. 1.

[0027] The filling layer 11 fills a space between the core section and the coil 9 completely. The filling layer 11 is made of a paramagnetic material, for example a soft magnetic material, which has a higher permeability number than air. It is especially preferable for the filling layer 11 to be made of a soft-magnetic composite material (SMC), in particular by pressing and sintering a soft-magnetic powder composite material. The filling layer 11 has an outer surface 13 which faces away from the core section and is in the shape of a cylinder with an oval, in particular circular guide curve 15.

[0028] The filling layer 11 supports the conduction of a magnetic flux of the magnetic core 1 of the transformer 3 by completely filling the cross-sectional area enclosed by the coil 9 with magnetizable material. Compared to a conventional transformer without the filling layer 11, less electrical steel is required for the same coil diameter in order to achieve the same magnetic flux. An exemplary calculation for a magnetic core 1 with a diameter of 29 cm and a cross-sectional area of 587.5 cm.sup.2 and the permeability number 2000 and a cross-sectional area of 660.5 cm.sup.2 enclosed by the coil 9 shows that the cross-sectional area of the magnetic core 1 can be reduced by about 1.3% in order to achieve the same magnetic flux with a filling layer 11 as without the filling layer 11, given the filling layer has the permeability number 200. Furthermore, a simulation based on a finite element method shows that in this example, as a result of the increased effective cross section for conducting the magnetic flux due to the filling layer 11, and by excitation with an electrical coil current of 12 kA, the magnetic flux density in the magnetic core 1 decreases from 193.7 mT to 189 mT, i.e., is reduced by 2% compared to an embodiment without the filling layer 11, and the magnetic core 1 is correspondingly relieved. A filling layer 11 with an even higher permeability number enables a further reduction in the cross-sectional area of the magnetic core 1 and thus a corresponding reduction in the amount of electrical lamination required to produce the magnetic core 1, or an even greater relief of the magnetic core 1.

[0029] Although the invention has been illustrated and described in more detail by preferred exemplary embodiments, the invention is not restricted by the examples disclosed and other variations can be derived therefrom by a person skilled in the art without departing from the scope of protection of the invention.