Capacitor for resonant circuits in power applications

Patent metadata

Field	Value
Publication number	US-11101076-B2
Application number	US-201816495963-A
Country	US
Kind code	B2
Filing date	Mar 21, 2018
Priority date	Mar 23, 2017
Publication date	Aug 24, 2021
Grant date	Aug 24, 2021

Abstract

A capacitive element is manufactured by using the multilayer printed circuit board technology. The body of the element includes a layer of dielectric material interposed between two layers of conductive material arranged on opposite sides of the layer of dielectric material. Each layer of conductive material is in turn covered, on its free side, with an external covering layer. The material for making the layer of dielectric material is chosen among materials having: —a dielectric permeability εr>1, —a dielectric rigidity k>100 kV/mm, and —a loss figure Df≤0.002. Furthermore, the dimensions of the layer of dielectric material are greater than the dimensions of the layers of conductive material, so as to limit the edge effects that might cause discharge phenomena and make the capacitive element flexible.

First claim

The invention claimed is:

1. A capacitive element manufactured by using the multilayer printed circuit board technology, wherein the body of the element comprises a layer of dielectric material interposed between two layers of conductive material arranged on opposite sides of said layer of dielectric material, wherein each layer of conductive material is in turn covered, on its free side, with an external covering layer; the material for making said layer of dielectric material is chosen among materials having:
a dielectric permeability εr>1,
a dielectric rigidity k>100 kV/mm, and
a loss figure Df≤0.002,
and wherein the dimensions of said layer of dielectric material are greater than the dimensions of said layers of conductive material, so as to limit the edge effects that might cause discharge phenomena and make said capacitive element flexible,
further wherein the capacitive element is configured to have a maximum peak voltage of >8 kV.

2. The capacitive element according to claim 1 , wherein said layer of dielectric material is chosen among materials having a dielectric permeability εr>2.

3. The capacitive element according to claim 1 , wherein said layer of dielectric material is chosen among materials having a dielectric rigidity k>250 kV/mm.

4. The capacitive element according to claim 1 , wherein said layer of dielectric material is chosen among a polyamide film, a fluorinated ethylene propylene (FEP) film and silicon oxide.

5. The capacitive element according to claim 1 , wherein said layer of dielectric material is chosen among materials that allow depositing the conductive material for making said layers of conductive material without requiring the use of glues.

6. The capacitive element according to claim 1 , wherein said external covering layers adhere perfectly to said layers of conductive material, so as to ensure that there will be no residual air in any interspaces, thus preventing local discharge phenomena.

7. The capacitive element according to claim 1 , wherein the material for said external covering layers is chosen in such a way as to ensure:
perfect adhesion to the conductive layers and to the dielectric layer;
a thickness that will prevent ionization of the air layers around the capacitive element; and
a dielectric rigidity that will prevent local discharge phenomena from arising, which might lead to perforation of the dielectric material.

8. The capacitive element according to claim 7 , wherein the dielectric rigidity of the material used for the external covering layers is equal to or greater than the dielectric rigidity of the material used for the dielectric layer.

9. The capacitive element according to claim 7 , wherein the thickness of the material used for the external covering layers is greater than or equal to the thickness of the material used for the dielectric layer.

10. The capacitive element according to claim 1 , wherein the connections of the conductive layers are effected by means of holes or patches formed on said external covering layers, whereon electric connection elements can be glued or soldered.

11. The capacitive element according to claim 1 , wherein the operating temperature Tw of the materials of the layer of dielectric material and of the external covering layers is Tw>200° C.

12. The capacitive element according to claim 1 , wherein the operating temperature Tw of the dielectric material and of the external covering layers is Tw>300° C.

13. The capacitive element according to claim 1 , wherein the capacitive element has a discoid shape.

14. A method for manufacturing a capacitive element according to the multilayer printed circuit board technology, comprising the steps of:
preparing a layer of dielectric material,
forming two layers of conductive material on opposite sides of said layer of dielectric material,
covering the free side of each layer of conductive material with an external covering layer,
selecting the material for making said layer of dielectric material among materials having:
a dielectric permeability εr>1,
a dielectric rigidity k>100 kV/mm, and
a loss figure Df≤0.002,

and wherein said method comprises the steps of:
selecting the dimensions of said layer of dielectric material in a manner such that they are greater than the dimensions of said layers of conductive material, so as to limit the edge effects that might cause discharge phenomena and to cause the capacitive element to have a peak voltage of >8 kV.

15. The method according to claim 14 , wherein said method comprises the step of selecting the material for making said layer of dielectric material among materials having a dielectric permeability εr>2.

16. The method according to claim 14 , wherein said method comprises the step of selecting the material for making said layer of dielectric material among materials having a dielectric rigidity k>250 kV/mm.

17. The method according to claim 14 , wherein said method comprises the step of selecting the material for making said layer of dielectric material among a polyamide film and a fluorinated ethylene propylene (FEP) film.

18. The method according to claim 14 , wherein said method comprises the step of selecting the material for making said layer of dielectric material among materials that allow depositing the conductive material for making said layers of conductive material without requiring the use of glues.

19. The method according to claim 14 , wherein said method comprises the step of causing said external covering layers to perfectly adhere to said layers of conductive material, so as to ensure that where will be no residual air in any interspaces, thus preventing local discharge phenomena.

20. The method according to claim 14 , wherein said method comprises the step of selecting the material for making said external covering layers in such a way as to ensure:
perfect adhesion to the conductive layers and to the dielectric layer;
a thickness that will prevent ionization of the air layers around the capacitive element; and
a dielectric rigidity that will prevent the dielectric material from collapsing.

21. The method according to claim 20 , wherein the dielectric rigidity of the material used for the external covering layers is selected to be equal to or greater than the dielectric rigidity of the material used for the dielectric layer.

22. The method according to claim 14 , wherein said method comprises the step of prearranging connections of the conductive layers by forming areas or patches on said external covering layers, whereon connection elements can be glued or soldered.

23. The method according to claim 14 , wherein said method comprises the step of selecting the materials of said layer of dielectric material and said external covering layers among materials having an operating temperature Tw>200° C.

24. The method according to claim 14 , wherein said method comprises the step of selecting the materials of said layer of dielectric material and said external covering layers among materials having an operating temperature Tw>300° C.

25. A multilayer printed circuit board comprising a capacitive element manufactured by using the method according to claim 14 .

Assignees

• Torino Politecnico

Inventors

• Guglielmi Paolo
• Freschi Fabio
• Cirimele Vincenzo

Classifications

• H01G4/14

  Organic dielectrics · CPC title

• H01G4/1209

  characterised by the ceramic dielectric material (H01G4/1272, H01G4/1281 take precedence) · CPC title

• H01G4/186

  halogenated (H01G4/145 takes precedence) · CPC title

• H01G4/224 Primary

  Housing; Encapsulation · CPC title

• H05K1/162

  incorporating printed capacitors · CPC title