DE102012222432A1 - Substrate i.e. printed circuit board, for supporting switching circuit, has carrier layer arranged for supporting switching circuit main portion, and first capacitor plate that is formed on opposite side of dielectric - Google Patents

Abstract

The substrate (26) has a first capacitor plate (28) and a second capacitor plate (30) which are separated by a dielectric (32) from each other. A carrier layer (34) is arranged for supporting a switching circuit main portion. The first capacitor plate is formed on an opposite side of the dielectric. A multilayer capacitor (25) is provided with the capacitor plates. A cooling element (42) i.e. liquid refrigerator, is provided on an opposed side of the carrier layer. The first and second electrical terminals (36, 38) are electrically connected with capacitor plates. Independent claims are also included for the following: (1) an electric circuit (2) an electromotor arrangement.

Description

Technical area

The invention relates to a substrate for supporting a circuit, an electrical circuit with the substrate and an electric motor motor assembly with a converter carried on the substrate.

State of the art

From the DE 151 40 23 A It is known to form on a substrate capacitor plates by vapor deposition of metal, wherein dielectrics are formed by anodizing the vapor-deposited capacitor plates.

From the DE 195 40 570 A1 It is known to form a capacitor by overlapping two conductor tracks, which are separated by a dielectric.

In the DE 10 2008 004 470 A1 it is disclosed to metallize two opposite surfaces of a substrate. The metallized surfaces thus form a capacitor.

From the DE 10 2010 040 861 A1 is a power output stage for an electronically commutated electric motor with a DC link capacity known.

Disclosure of the invention

According to the invention a substrate for supporting a circuit according to claim 1 and an electrical circuit and an electric motor according to the independent claims.

Preferred embodiments are specified in the dependent claims.

According to an aspect of the invention, a substrate for supporting a circuit comprises a first capacitor plate and a second capacitor plate separated by a dielectric and a support layer for supporting the circuit formed on the first capacitor plate on a side opposite to the dielectric ,

The specified substrate is based on the consideration that a power output stage of the type mentioned could be carried on this. This includes, in addition to several switches for forming a bridge circuit known per se, an intermediate circuit capacitor, which is connected, for example, in a vehicle with an electric motor to relieve the on-board network and to increase the efficiency of the electric motor in the power output stage. Further application examples are also DC-DC converter circuits, such as e.g. Buck or boost converter.

Based on this consideration, however, the stated substrate is based on the finding that the DC link capacitance could be exposed to high reactive powers, in particular in the above power output stage. In this case, the DC link capacitance does not only have to absorb a large amount of reactive energy and buffer it, a DC link capacitor forming the DC link capacitance is also considerably warmed up in this way. For this reason, the DC link capacitance must not only have a sufficiently high capacitance value, the corresponding DC link capacitor will also be geometrically correspondingly large. With the warming up of the DC link capacitor associated cooling requirements further aggravate the problem.

In contrast, the stated substrate is based on the idea of at least partially accommodating a capacitor which could realize, for example, the aforementioned DC link capacitance in the substrate. The capacitor thus created can be made very extensive, whereby a large cooling surface is guaranteed for optimal heat dissipation from the capacitor. The effective capacitor area is also sufficiently high to accommodate the above reactive power.

In one embodiment of the above substrate, the carrier layer and the dielectric are formed of a same material in which the capacitor plates are embedded. This embodiment is based on the consideration that the dielectric as well as the carrier layer ultimately fulfill the same electrical task, that is to say to electrically separate circuit elements such as electrical conductor tracks and the capacitor plates. Therefore, both should have the highest possible dielectric constant. In the context of this embodiment, this knowledge is used, and the capacitor plates embedded in one and the same material, which significantly reduces the production cost of the above substrate.

The substrate may be built on any circuit boards known to those skilled in the art, such as FRx printed circuit boards, printed circuit boards or multilayer hybrids (Al2O3) or DBC-related substrates

In an additional embodiment of the above substrate, the above substrate comprises first and second electrical connections on the carrier layer corresponding to the first and second capacitor plate are electrically connected. Thus, the capacitor thus created can also reduce parasitic effects such as unwanted inductances, since the electrical connections to the capacitor can be arranged virtually everywhere on the carrier layer and thus formed extremely short. This reduces the area of the so-called Kommutierungskreises consisting of DC link capacitor and power output stage, which in turn has a reduction in losses in the power output stage result.

In a particular embodiment of the above substrate, the capacitor plates are part of a multilayer capacitor. In this way, the capacitance value of the capacitor can be further increased, which is advantageous in particular when using the capacitor as the above-mentioned DC link capacity, which requires a very high capacitance value for receiving reactive power.

In another embodiment of the above substrate, a cooling element is disposed on an opposite side of the support layer. This cooling element can attack over a wide area due to the large geometric extent of the capacitor and thus achieve a particularly good cooling performance in the cooling of the capacitor.

According to another aspect of the invention, an electrical circuit comprises an above substrate and a circuit carried on the carrier layer.

The above electrical circuit is based on the consideration that the capacitor is quasi hidden in the substrate and so on the substrate surface, so on the carrier layer, no longer takes away space for other components of the electrical circuit. In this way, the electrical circuit can be constructed with an improved packing density. Surprisingly, the capacitor accommodated in the substrate also increases the electromagnetic compatibility of the above electrical circuit because it minimizes possible parasitic inductances due to the directly short-circuited capacitor.

In one embodiment of the above electrical circuit, the circuit comprises a power converter. The power converter can be designed arbitrarily. For example, B6 full bridges, H-bridges or half-bridge modules which are known per se to the person skilled in the art are suitable as power converters. The above electrical circuit can be used in automotive electronics control units in the range of a few 100W up to areas with a few kW, as used in power modules for Light E-Mobility, hybrid vehicles and solar inverters.

In a particular embodiment of the above electrical circuit, the power converter may have a DC link capacitance comprising a capacitor comprising the capacitor plates. As already mentioned, this DC link capacitance can be realized with a particularly high capacitance value, wherein heat can be effectively dissipated from the capacitor plates themselves.

If the capacitance value of the capacitor accommodated in the substrate is nevertheless insufficient, the DC link capacitance may comprise a further capacitor which is carried on the carrier layer. Even in this case, a reduction of the above-mentioned parasitic effects by the capacitor accommodated in the substrate can be seen.

In a particular embodiment, the above electrical circuit comprises a housing, wherein the substrate is part of the housing.

According to a further aspect of the invention, an electric motor arrangement comprises an electric motor and an above power converter for the electrical power supply for the electric motor. The power converter can serve the electric motor as a power amplifier, which performs the same function as the aforementioned power output stage.

Brief description of the drawings

Preferred embodiments will be explained in more detail with reference to the accompanying drawings. Show it:

1 a schematic representation of a vehicle with an electric motor assembly;

2 a schematic representation of the electric motor assembly with a power converter; and

3 a schematic representation of a substrate of the power converter.

Description of the embodiments

In the figures, elements of identical or comparable function are provided with the same reference numerals and described only once.

It will open 1 Referred to a vehicle 2 with an electric motor assembly 4 for propulsion of the vehicle 2 shows. The electric motor assembly 4 is via a drive shaft 6 with edges 8th of the vehicle 2 mechanically connected to its propulsion. The electric motor assembly 4 is further via an electrical connection 10 with an electrical energy storage 12 connected. The electric motor assembly 4 includes an electric motor 14 and a power converter 16 and is part of a vehicle electrical system 17 of the vehicle 2 , this in 1 is shown in sections. In operation of the vehicle 2 converts the power converter 16 in the energy store 12 stored electrical energy in 2 shown phase currents 21 um and supplies the electric motor 14 for its operation with these phase currents 21 ,

The power converter 16 is explained below 2 described in more detail. In 2 is the power converter 16 at least formed as part of a circuit and comprises between two electrical supply lines 18 a B6 bridge circuit known per se to a person skilled in the art 20 with six circuit breakers 22 , The circuit breakers 22 transform the energy storage 12 in the form of direct current 19 Provided electrical energy in the above three phase currents 21 um and guide the phase currents 21 on the stator windings 23 of the electric motor 14 on. Parallel to the B6 bridge circuit 20 and between the two supply lines 18 instructs the power converter 16 a DC link capacity 24 auf, by at least one capacitor to be described below 25 is realized.

The DC link capacity 24 stores, for example, induction currents when commutating the electric motor 14 arise, thus reducing fluctuations in the DC and phase currents 19 and 21 and thus protects the electrical system 17 , In this way, the efficiency of the electric motor 14 increases and the EMC emissions are reduced.

The following will be on 3 Reference is made to a structure of the power converter 16 including a substrate 26 is shown schematically in a cross-sectional view. To reduce the space requirement of the power converter 16 is at least part of the DC link capacity 24 So the capacitor 25 in the substrate 26 recorded on the B6 bridge circuit 20 or at least part of the B6 bridge circuit 20 worn.

The substrate 26 includes a number of first capacitor plates 28 and the same number of second capacitor plates 30 , The first capacitor plates form 28 the first electrode, so the first electrical loading surface of the capacitor 25 and the second capacitor plates 30 the second electrode, so the second electrical loading surface of the capacitor 25 out. Here are the first capacitor plates 28 and the second capacitor plates 30 layer by layer alternately overlapping each other but spaced from each other. This indicates the substrate 26 between adjacent capacitor plates 28 and 30 Cavities up. These cavities are of a dielectric 32 filled, the neighboring capacitor plates 28 and 30 electrically isolated from each other.

In a line of sight 33 considered, lies on one of the dielectric 32 opposite side has the substrate 26 on top of the first capacitor plate 28 an electrically non-conductive carrier layer 34 on. On one of the capacitor plates 28 and 30 opposite side of this carrier layer 34 are also a first electrical connection 36 and a second electrical connection 38 provided, which in each case with the first capacitor plates 28 or the second capacitor plates 30 are electrically connected. This first and second connection 36 . 38 each form the positive and the negative power connection of the capacitor 25 out. On the same side of the carrier layer 34 are also the B6 bridge circuit 20 that is, the circuit breakers 22 the B6 bridge circuit 20 arranged. There are also bonding wires 40 between some of the circuit breakers 22 and the first connection 36 provided for electrical connection between these parts.

In the direction of view 33 on one of the dielectric 32 opposite side has the substrate 26 on the lower second capacitor plate 30 an insulation layer 42 on. On one of the second capacitor plate 30 opposite side of this insulation layer 42 is a cooling element 44 with cooling fins 46 carried. The cooling element 44 is with the capacitor plates 30 or the capacitor 25 thermally conductive but through the insulation layer 42 contacted electrically insulating. When the cooling element 44 to the electrical potential of the second capacitor plate 30 may be set, the insulation layer 42 between the cooling element 44 and the second capacitor plate 30 also omitted. The cooling element 44 take those in the condenser 25 resulting from the B6 bridge circuit 20 to the capacitor 25 transferred heat and gives the heat absorbed by the cooling fins 46 to the environment. In this way, the cooling element cools 44 the capacitor 25 and the B6 bridge circuit 20 ,

The dielectric 32 , the backing layer 34 and the insulation layer 42 are made of a same material, such as polyethylene, which has a high relative dielectric constant. In this case, the polyethylene as a liquid casting compound in a casting process on the layers alternately overlapping each other and arranged spaced from each other, the first and second capacitor plates 28 and 30 are poured, wherein the liquid material, the cavities between the first and the second capacitor plates 28 and 30 crowded. After hardening, the material forms Polyethylene the dielectric 32 and thus isolates the capacitor plates 28 and 30 each other electrically. In addition, the material transfuses the first and the second capacitor plates during casting 28 and 30 and forms the support layer after hardening 34 and the insulation layer 42 , In this way, the first and second capacitor plates 28 and 30 electrically isolated from the environment and protected from environmental influences.

The capacitor 25 is thus as part of the substrate 26 in the substrate 26 integrated. Through the multi-layer capacitor plates 28 and 30 and the dielectric 32 made of polyethylene, the substrate 26 with the integrated capacitor 25 a high mechanical stability and heat resistance.

Are one or more other capacitors in addition to the capacitor described above 25 as DC link capacity 24 required, they can be designed as known aluminum electrolytic or film capacitors and on the same side of the carrier layer 34 like the B6 bridge circuit 20 to be ordered. Because of that, part of the DC link capacity 24 as the capacitor 25 in the substrate 26 integrated, these additional capacitors can be made smaller. Thus, the space required for the DC link capacity 24 be reduced.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 1514023 A [0002]
• DE 19540570 A1 [0003]
• DE 102008004470 A1 [0004]
• DE 102010040861 A1 [0005]

Claims (10)

Substrate ( 26 ) for supporting a circuit comprising a first capacitor plate ( 28 ) and a second capacitor plate ( 30 ) passing through a dielectric ( 32 ) are separated from each other, and a carrier layer ( 34 ) for carrying the circuit, which on the first capacitor plate ( 28 ) on a dielectric ( 32 ) opposite side is formed. Substrate ( 26 ) according to claim 1, wherein the carrier layer ( 34 ) and the dielectric ( 32 ) are formed of a same material, in which the capacitor plates ( 28 . 30 ) are embedded. Substrate ( 26 ) according to claim 1 or 2, comprising a first ( 36 ) and second ( 38 ) electrical connection on the carrier layer ( 34 ), which correspond with the first ( 28 ) and second ( 30 ) Capacitor plate are electrically connected. Substrate ( 26 ) according to one of the preceding claims, wherein the capacitor plates ( 28 . 30 ) Part of a multilayer capacitor ( 25 ) are. Substrate ( 26 ) according to one of the preceding claims, comprising a cooling element ( 42 ) on one of the carrier layer ( 34 ) opposite side, which is designed in particular as a liquid cooling. Electrical circuit comprising a substrate ( 26 ) according to one of the preceding claims and a circuit formed on the carrier layer ( 34 ) is worn. An electrical circuit according to claim 6, wherein the circuit comprises a power converter ( 16 ). Electrical circuit according to claim 7, wherein the power converter ( 16 ) a DC link capacity ( 24 ) having a capacitor ( 25 ) comprising the capacitor plates ( 28 . 30 ). An electrical circuit according to claim 8, wherein the DC link capacitance ( 24 ) comprises a further capacitor which is disposed on the carrier layer ( 34 ) is worn. Electric motor assembly comprising an electric motor ( 14 ) and a power converter ( 16 ) according to one of the preceding claims 7 to 9 for its electrical power supply.

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