EMC-filter

Abstract

The invention which relates to an EMC filter (1) addresses the problem of specifying an EMC filter (1) that is simple of structure, cost-effective and temperature resistant. This problem is resolved thereby that the core of the choke (4, 5) is comprised of one or two core parts (10), that at least one first planar or convex heat transfer area (23) is located on an outside of the core and that the core with this first planar or convex heat transfer area (23) is disposed on a housing (12) of the refrigerant compressor, wherein the housing (12) in the region of the first planar or convex heat transfer area (23) is implemented planar or concave.

Claims

1. An electromagnetic compatibility (EMC) filter connected to an inverter of a refrigerant compressor and comprising at least one choke with a core and several capacitors, wherein the core of the choke is developed having one or two core parts, wherein at least one first planar or convex heat transfer area is disposed on an outside of the core, wherein the core with this first planar or convex heat transfer area is disposed on a housing of the refrigerant compressor, wherein the housing in the region of the first planar or convex heat transfer area is implemented planar or concave; wherein as the winding of the choke in the core a bus bar is disposed; and wherein the bus bar is electrically conducting connected to the circuit board of the inverter and wherein the capacitors of the passive EMC filter are disposed on the circuit board.

2. An EMC filter as in claim 1, wherein a second planar or convex heat transfer area is disposed on the outside of the core, and wherein the second planar or convex heat transfer area is disposed oriented in parallel or oppositely to the first planar or convex heat transfer area.

3. An EMC filter as in claim 1, wherein a bracket is disposed on a second planar or convex heat transfer area of the core and wherein the bracket is connected with the housing.

4. An EMC filter as in claim 1, wherein a cap is disposed on a second planar or convex heat transfer area of the core, wherein the cap is connected with the housing, and wherein the cap in the region of the second planar or convex heat transfer area is implemented planar or concave.

5. An EMC filter according to claim 1, wherein a thermally conductive layer is disposed between the first planar or convex heat transfer area and the housing.

6. An EMC filter according to claim 1, wherein a thermally conductive layer is disposed between the second planar or convex heat transfer area and the bracket or the cap.

7. An EMC filter according to claim claim 5, wherein a thermally conductive paste or a gap pad is disposed as the thermally conductive layer.

8. An EMC filter according to claim 1, wherein plate washers are disposed on a bracket plate, wherein the plate washers include holes for screws, bolts or adjusting pins; and wherein the bracket and the plate washers are bolted or secured on the housing with the screws, the bolts or the adjusting pins.

9. An EMC filter as in claim 2, wherein a cap is disposed on the second planar or convex heat transfer area of the core, and wherein the cap is connected with the housing, wherein the cap in the region of the second planar or convex heat transfer area is implemented planar or concave.

10. An EMC filter according to claim 2, wherein a thermally conductive layer is disposed between the first planar or convex heat transfer area and the housing.

11. An EMC filter according to claim 3, wherein a thermally conductive layer is disposed between the first planar or convex heat transfer area and the housing.

12. An EMC filter according to claim 4, wherein a thermally conductive layer is disposed between the first planar or convex heat transfer area and the housing.

13. An EMC filter as in claim 2, wherein a bracket is disposed on a second planar or convex heat transfer area of the core and wherein the bracket is connected with the housing.

14. An EMC filter as in claim 2, wherein a bracket is disposed on a second planar or convex heat transfer area of the core and wherein the bracket is connected with the housing.

15. An EMC filter as in claim 4, wherein a bracket is disposed on a second planar or convex heat transfer area of the core and wherein the bracket is connected with the housing.

16. An EMC filter according to claim 4, wherein a thermally conductive layer is disposed between the first planar or convex heat transfer area and the housing.

17. An EMC filter according to claim 3, wherein plate washers are disposed on a bracket plate, wherein the plate washers include holes for screws, bolts or adjusting pins; and wherein the bracket and the plate washers are bolted or secured on the housing with the screws, the bolts or the adjusting pins.

18. An EMC filter according to claim 4, wherein plate washers are disposed on a bracket plate, wherein the plate washers include holes for screws, bolts or adjusting pins; and wherein the bracket and the plate washers are bolted or secured on the housing with the screws, the bolts or the adjusting pins.

19. An EMC filter according to claim 5, wherein plate washers are disposed on a bracket plate, wherein the plate washers include holes for screws, bolts or adjusting pins; and wherein the bracket and the plate washers are bolted or secured on the housing with the screws, the bolts or the adjusting pins.

20. An EMC filter according to claim 6, wherein plate washers are disposed on a bracket plate, wherein the plate washers include holes for screws, bolts or adjusting pins; and wherein the bracket and the plate washers are bolted or secured on the housing with the screws, the bolts or the adjusting pins.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1: an exemplary circuit configuration of a passive EMC filter according to prior art,

(2) FIG. 2, 2a: a core, comprised of four parts, of a choke,

(3) FIG. 3: a first embodiment of the invention, and

(4) FIG. 4: a second, alternative embodiment of the invention.

DETAILED DESCRIPTION

(5) FIG. 1 shows an exemplary circuit configuration of a passive EMC filter 1 according to prior art, which is connected to an inverter 2. The EMC filter 1 includes an input 3 at which, for example a voltage of 48 V can be applied, and comprises the chokes L.sub.1 4 and L.sub.2 5 disposed in feed lines HV+ and HV. While the first capacitor 6 denoted C.sub.1 is disposed between lines HV+ and HV directly at the input of the passive EMC filter 1 and before the chokes L.sub.1 4 and L.sub.2 5, the second capacitor 7, denoted C.sub.2 is disposed after chokes L.sub.1 4 and L.sub.2 5 at the input of inverter 2.

(6) The third capacitor 8 denoted C.sub.3 is disposed between line HV and ground potential. The fourth capacitor 9 denoted C.sub.4 is disposed between line HV+ and ground potential.

(7) In this known circuit configuration on a housing 12 a core, disposed according to the invention on a housing 12 of a refrigerant compressor, can be found in the first choke 4 and optionally also in the second choke 5.

(8) In FIGS. 2 and 2a is depicted a core, comprised of four parts, of a choke 4 or a choke 5 from FIG. 1. The core could alternatively also be comprised of two parts.

(9) In FIG. 2 shown on the left the core with its four core parts 10 is depicted after assembly and encompasses the bus bar 11 of copper which represents the winding of choke 4 or choke 5.

(10) On the right of FIG. 2a the two upper core parts 10 are depicted after they have been raised. It can be seen that the core parts 10 are implemented in C form and through this specific form enable receiving the bus bar 11 having a rectangular cross section. The core parts 10 in the assembled state of the core are firmly secured in their position by suitable, not shown, means.

(11) In the core depicted in FIG. 2 a first planar heat transfer area 23 is developed on the undersurface of the core. A second planar heat transfer area 23, oriented parallel to the first heat transfer area 23, is developed on the upper surface of the core and is indicated in FIG. 2 by means of simple hatching.

(12) FIG. 3 shows a first embodiment of the invention. Into a housing 12 of a refrigerant compressor a coolant 13 is introduced which is completely enclosed by the housing 12. Housing 12 is produced of a metallic material, for example as an injection molded part, and has good thermal conductivity.

(13) On a surface 14 of housing 12 a core is disposed, comprised of two C-shaped core parts 10, of a choke 4, 5 of a passive EMC filter 1. For the safe securement of the core with its first planar heat transfer area 23 on the planar surface 14 of housing 12 and for a firm coherence of the core parts 10, a U-shaped bracket 15 is to be disposed. This bracket 15 can be adhered at its ends to the surface 14. Alternatively, the ends of the bracket 15 can be implemented with plate washers 16 having holes through which the plate washers 16 of the bracket 15 can be bolted to the housing 12.

(14) The core is consequently connected with its second planar heat transfer area 23 to the bracket 15 such that it is thermally conductive.

(15) It is, alternatively, feasible to dispose the core with its first convex heat transfer area 23 on a concave surface 14 of housing 12 and, for a firm coherence of the core parts 10, to dispose a bracket 15 formed corresponding to the surface of the core. This implementation of the core with a convex surface in the region of the heat transfer area 23 is not shown in FIGS. 1 to 4.

(16) FIG. 3 shows in sectional representation the core as well as the bus bar 11 extending through the core. In the example in FIG. 3, in which the core has a rectangular opening, the bus bar 11 is implemented with a rectangular cross section area. It is understood that the cross section can also have a different shape, such as a square area, an n-gonal area or a circular area and be adapted to the opening of the core. The ends of the windings of the choke, also of the bus bar 11, extending upwardly in FIG. 3 are electrically connected to the circuit board 18 of the inverter. Such a connection can be implemented for example as a bolt or a solder connection. On this multi-layer circuit board 18 the capacitors 6, 7, 8 and 9 that belong to the passive EMC filter 1 can be disposed. In addition, on the, for example, multi-layer circuit board 18 the components associated with the inverter 2 are disposed.

(17) The described elements can be covered by means of a cap 19 and thus can be safely placed against penetration of dirt and moisture.

(18) As is intended to be shown by the wavy arrows, the heat 20 in the lower region of the core can drain directly, or be dissipated across a thermally conductive layer 21, to the housing 12 cooled with coolant 13. Such a thermally conductive layer 21 can be a thermally conductive paste, a thermally conductive adhesive or a gap pad.

(19) In the upper region of the core the heat 20 can be dissipated across the bracket 15 to the housing 12. In this way improved cooling of the core of a choke 4, 5 in a passive EMC filter 1 is achieved. This improved cooling serves for maintaining parameters which ensure the reliable function of the choke 4, 5 and consequently of the EMC filter 1. Through the improved cooling, in addition, the overdesigning of structural parts, in particular of the choke 4, 5, can be dispensed with, which results in savings of costs and materials.

(20) In FIG. 4 an alternative second embodiment of the invention is shown. In housing 12 of the refrigerant compressor a coolant 13 is introduced which is completely enclosed by housing 12. Housing 12 is fabricated of a metallic material, for example as an injection molded part, and has good thermal conductivity.

(21) On a surface 14 of housing 12 a core, comprised of two C-shaped core parts 10, of a choke 4, 5 of a passive EMC filter 1 is disposed. For the safe securement of the core with its first planar heat transfer area 23 on the planar surface 14 of the housing 12, a cap 19 is provided which is placed onto the edge of the housing 12 and securely closes off the volume in which the choke 4, 5 as well as the circuit board 18 of inverter 2 are disposed.

(22) The secure hold of the core is achieved thereby that the first planar heat transfer area 23 is in contact on housing 12, while the second planar heat transfer area 23, located parallel to the first heat transfer area 23, is in contact on a planar inner wall of cap 19.

(23) Stated differently, the core is firmly clamped between the housing 12 and the cap 19.

(24) In this embodiment it is also provided to insert a thermally conductive layer 21, such as a thermally conductive paste or a gap pad, between the first planar heat transfer area 23 of the core and the planar surface 14 of the housing 12. Similarly, between the second planar heat transfer area 23 of the core and the cap 19 a further thermally conductive layer 21 is disposed. The two thermally conductive layers 21, implemented as gap pads for example, therewith improve the heat dissipation in the upper and lower regions of the core and serve for the secure hold of the core even in the presence of customarily occurring vibrations in a refrigerant compressor of a motor vehicle.

(25) The core can, alternatively, be disposed, for example, with its first convex heat transfer area 23 on a concave surface 14 of housing 12. The second heat transfer area 23 can also be implemented convex or planar. If the second heat transfer area 23 is implemented convex, a concave region is provided in the cap to receive the core and to hold it securely. If the second heat transfer area 23 is implemented planar, in the cap a region for the heat transfer area 23 is also implemented planar.

(26) In the example depicted in FIG. 4 the winding of choke 4, 5 is disposed in the circuit board 18. In the multi-layer circuit board 18 copper tracks in several planes, which run in the interior of the core and are electrically interconnected, are utilized for forming the winding in the core. For this purpose, in the circuit board 18 appropriate notches are provided in order to be able to arrange the core, comprised of two core parts 10, about the portion of the circuit board 18 which represents the winding of choke 4, 5. The portion of the circuit board 18 that represents the winding of choke 4,5 or the bus bar, is denoted in FIG. 4 by the reference number 11.

(27) On the circuit board 18 are additionally located the capacitors 6, 7, 8 and 9 associated with the passive EMC filter 1, as well as the components associated with the inverter 2.

(28) As is shown in FIG. 3, the winding of choke 4, 5 can alternatively also be implemented in the form of a U-shaped bus bar 11.

(29) In the lower region of the core the heat 20 can be dissipated directly from the core across thermally conductive layer 21 into the cooled housing 12 of the refrigerant compressor. In the upper region of the core the heat 20 is dissipated into the cap 19 and across it to the housing 12. In this embodiment, consequently, improved cooling of the core of a choke 4, 5 in a passive EMC filter 1 can also be achieved.

(30) To secure the cap 19 on the housing 12 of the refrigerant compressor, at least two fasteners 22 can be applied which serve for the safe securement of cap 19 on housing 12 and also allow opening the cap for maintenance and repair work.

LIST OF REFERENCE NUMBERS

(31) 1 EMC filter 2 Inverter 3 Input (HV+/HV) 4 First choke L.sub.1 5 Second choke L.sub.2 6 First capacitor C.sub.1 7 Second capacitor C.sub.2 8 Third capacitor C.sub.3 9 Fourth capacitor C.sub.4 10 Core parts of choke 11, 11 Bus bar 12 Housing 13 Coolant 14 Surface 15 Bracket 16 Plate washer 17 Bolt 18 Circuit board 19 Cap 20 Heat 21 Thermally conductive layer (gap pad) 22 Fasteners 23, 23 Heat transfer area