EP3288046A1 - Coil device - Google Patents

Abstract

A coil device (1) for a power converter is proposed which comprises a cooling plate (2) and a plurality N of coil windings (4), wherein the cooling plate (2) is thermally coupled to at least one end face (400) of one of the coil windings (4) is. According to the invention, the coil windings (4) are spatially offset by an angle (41) of 2 À / N, and the cooling plate (2) has a cooling channel (24) extending at least partially around each of the N coil windings (4) ,

Description

The invention relates to a coil device according to the preamble of claim 1.

From the prior art, a plurality of coil devices, such as choke coils, which are wound from several layers of an insulated conductor known. Due to the electrical stress of a coil device occur thermal losses, for example, within the windings of the coil device or in its coil core, which is formed for example of iron on. Typically, the individual windings of the coil device are electrically isolated from each other by the introduction of an insulating material. Here, a sufficiently good heat dissipation of the coil device is ensured. A preferred cooling or cooling of the coil device or its winding layers is dimensioned contact, so that the predetermined space can be optimally utilized. For this purpose, for example, a cooling plate is introduced into the coil device, which in particular must be electrically insulated from a yoke of a winding of the coil device. However, the introduction of a cooling plate, in particular a metallic cooling plate, within the coil device has the disadvantage that due to the magnetic fields occurring electrical currents are induced in this, leading to losses (ohmic losses due to eddy currents).

Furthermore, known from the prior art water cooling, which are used in particular for inductors, and based on an introduction of metallic heat sinks in the coil device.

Waveguides are known from the prior art, which are used for the windings of the coil device. By the waveguides can be passed a coolant, which warms the coil device.

From the DE 10 2012 217 607 A1 Plastic cooling bags are known with a Y-structure, which can be introduced into the coil device or one of its windings. In order to increase the thermal conductivity between the windings of the coil device and said Y-structure, these are at least partially embedded in a resin, so that air pockets can be reduced or at best prevented. Furthermore, it is known to completely shed coil devices, in particular choke coils, so that an improved internal thermal conductivity is achieved.

From the EP 2977996 A1 is a choke coil of a power converter is known, which has a hollow cylindrical coil winding on the top surface of a cooling plate is thermally connected. This has the disadvantage that forms eddy currents within the cooling plate, which lead to losses. Furthermore, it has been found that cooling the cooling plate to heat it is technically difficult.

The present invention is based on the object to provide a coil device with improved cooling.

The object is achieved by a coil device having the features of the independent claim 1. In the dependent claims advantageous refinements and developments of the invention are given.

The coil device for a power converter according to the invention comprises a cooling plate and a plurality N of coil windings, wherein the cooling plate is thermally coupled to at least one end face of one of the coil windings. According to the invention, the coil windings are spatially offset by an angle of 2π / N (= 360 ° / N ) and the cooling plate has a cooling channel that extends at least partially around each of the coil windings.

In other words, the coil device has at least two coil windings. In this case, the cooling channel extends around each of the two coil windings. This advantageously ensures improved cooling of the coil windings. In this case, the end face of the coil winding is particularly preferred, since this typically has a sufficiently large area and is thus particularly well suited for the heat dissipation of the coil windings.

The inventive symmetrical design of the coil device, which is given by the spatial arrangement of the coil windings at an angle of 2π / N , results in an electromagnetically advantageous arrangement, which is especially preferred for cooling the coil device.

The cooling plate and its cooling channel can be produced, for example, by means of a regenerative method, in particular a 3D printing. Furthermore, the cooling channel is suitable for receiving a coolant, for example water, in particular a fluoroketone, for cooling or heat dissipation of the coil device. Particularly preferably, the coolant provided for the cooling is electrically non-conductive. As a result, eddy currents can advantageously be reduced within the cooling plate.

A further advantage of the present invention is that all coil windings of the coil device are cooled by means of a common cooling channel. In this case, according to the invention, the cooling channel extends at least partially around each of the coil windings. This makes it possible to achieve a mechanically advantageous and compact design of the coil device. Furthermore, the mechanical stability of the coil device is improved by the cooling plate. For example, the coil device can be pressed by means of the cooling plate or by means of a plurality of cooling plates, so that the weight of the coil device according to the invention can be reduced and additional space can be saved.

According to a particularly advantageous embodiment of the invention, the coil device comprises exactly three coil windings.

As a result, a particularly preferred symmetrical configuration of the coil device is provided. In particular, the three coil windings correspond to the three known phases of the three-phase alternating current. In other words, a coil device is provided for each phase of the three-phase alternating current. The coil device according to the invention can thus be provided for a power converter, in particular a converter.

Furthermore, in this case the extension of the cooling channel takes place such that it extends as long as possible and as close as possible to the coil windings. As a result, the cooling of the coil device by means of the cooling plate is advantageously improved.

It is particularly preferred in this case if the cooling channel extends over an angle of at least 5π / 3 (= 300 °), in particular of 11π / 6 (= 330 °), particularly preferably of 2π (= 360 °), around the respective coil winding ,

In other words, an angle range of at most π / 3 (= 60 °), in particular of at most π / 6 (= 30 °), preferably results around the coil winding in which the cooling channel does not surround it. Advantageously, this further improves the cooling of the coil device, in particular its coil windings.

In a preferred embodiment of the invention, the cross section of the cooling channel in the region of the coil winding is increased.

Due to the enlarged cross section of the cooling channel in the region of the coil winding, advantageously more heat can be dissipated from the coil windings. Overall, this further improves the cooling of the coil device or the coil windings.

According to an advantageous embodiment of the invention, the cooling plate is triangular or triangular in shape.

Advantageously, this results in a symmetrical design of the cooling plate, which is particularly advantageous for exactly three coil windings. Thus, the geometric shape or the geometric configuration of the cooling plate is adapted to exactly three coil windings. As a result, space can be saved advantageously. In particular, it is provided here that the corners of the triangular or triangular-shaped formed cooling plate are rounded, so that further space can be saved.

In this case, it is particularly preferred if the cooling plate has three side edges, wherein the cooling channel extends along two side edges of the three side edges.

As a result, the heat is advantageously discharged via at least two of the side edges to the surroundings of the cooling plate. At the further side edge, at which the cooling channel does not extend, the flow and the return for the cooling channel and / or further mechanical, electrical, thermal and / or fluidic connections for the coil device can advantageously be provided.

In an advantageous embodiment of the invention, the cooling plate has at least one recess, in particular a slot.

Advantageously, thereby the occurrence of eddy currents and their effects can be reduced. As a result, the heat dissipation of the coil device and the cooling plate is advantageously improved. Furthermore, the efficiency of an electric machine comprising, for example, the coil device is improved.

It is particularly preferred if the recess is star-shaped or star-shaped.

As a result, a particularly advantageous reduction of eddy currents within the cooling plate is achieved.

Furthermore, it is preferred in this case if the recess is formed from a plurality of slots, wherein the slots, starting from a common center, extend in a star-like manner in different directions.

According to a particularly preferred embodiment of the invention, in this case the cooling channel extends like a lug between the slots.

Advantageously, this improves the cooling of the cooling plate and achieves a reduction of eddy currents. This is the case because increased by the tab-like extension of the cooling channel its length and thus more heat can be transmitted.

In a further advantageous embodiment of the invention, the cooling plate is arranged on winding cores of the coil windings, wherein a winding core facing side surface of the cooling plate has an electrically insulating layer or coating.

In other words, the cooling plate is constructed at least in two parts. The first part of the cooling plate, which comprises the cooling channel, is made of aluminum and / or copper, for example, that is, a metallic and highly thermally conductive material is formed. A second part of the cooling plate is formed by means of the electrically insulating layer or coating. For this purpose, it is advantageous to provide Noryl and / or Ryton for the electrically insulating layer or the coating. Advantageously, the cooling plate can thereby be electrically insulated from live parts of the coil device.

Furthermore, an electrically insulating thermal interface material (TIM) can be provided for the electrically insulating layer. In addition, the use of less water-absorbing plastics, in particular of PPS or a ceramic, for example aluminum nitrite, is advantageous. As a result, a cost-effective construction of the coil device is made possible, in which the guide of a coolant in the metallic part of the cooling plate (first part) is arranged and the electrically insulating components of the cooling plate, that is, the electrically insulating layer formed by simple end plates without contacting and contouring are.

In this case, it is preferable if, for example, as stated above, a side surface of the cooling plate facing away from the winding core has an electrically insulating layer or coating.

As a result, the winding cores and the coil windings of the coil device can be insulated from a yoke, in particular an iron yoke.

According to an advantageous embodiment of the invention, the cooling plate made of aluminum, copper, stainless steel or copper ferrite or a mixture thereof is formed.

In this case, the cooling plate may comprise further materials or substances, for example plastics, in particular PPS or a ceramic, for example aluminum nitride. The mentioned Metallic materials, that is, aluminum, copper, stainless steel or copper-nickel ferrite advantageously have a high thermal conductivity, so that the thermal heat dissipation of the coil device or the cooling plate is improved.

In an advantageous development of the invention, each of the coil windings on a contacting element for electrical contacting, wherein each of the contacting elements is at least partially surrounded by the cooling channel.

Advantageously, this further improves the cooling of the coil device and of the cooling plate. In particular, as a result, the contacting elements are also at least partially cooled by the cooling channel which at least partially surrounds them.

Preferably, the contacting elements are in this case designed as copper tabs, in particular as bent copper tabs.

Advantageously, this improves the electrical contacting of the coil device and increases the thermal conductivity of the contacting elements.

Figur 1

eine schematische Draufsicht einer erfindungsgemäßen Spulenvorrichtung mit einer dreiecksartigen Kühlplatte;

Figur 2

eine weitere schematische Draufsicht einer erfindungsgemäßen Spulenvorrichtung, wobei eine Kühlplatte der Spulenvorrichtung T-förmig ausgebildet ist;

Figur 3

eine weitere Draufsicht einer erfindungsgemäßen Spulenvorrichtung, wobei hierbei die Kühlplatte sternenartig ausgebildet ist;

Figur 4

eine seitliche Darstellung einer erfindungsgemäßen Spulenvorrichtung.

Further advantages, features and details of the invention will become apparent from the embodiments described below and with reference to the drawings. Shown schematically:

FIG. 1

a schematic plan view of a coil device according to the invention with a triangular-type cooling plate;

FIG. 2

a further schematic plan view of a coil device according to the invention, wherein a cooling plate of the coil device is T-shaped;

FIG. 3

a further plan view of a coil device according to the invention, wherein in this case the cooling plate is formed like a star;

FIG. 4

a side view of a coil device according to the invention.

Similar, equivalent or equivalent elements may be provided with the same reference numerals in the figures.

In FIG. 1 is a schematic plan view of the coil device 1 according to the invention shown. In this case, the coil device 1 comprises a cooling plate 2, which has a cooling channel 24. The cooling channel 24 is designed and provided for guiding a coolant, for example water or a fluid, which in particular comprises a fluoroketone. For this purpose, the cooling channel 24 has a flow 61 and a return 62.

The cooling plate 2 of the coil device 1 is formed like a triangle. Here, the cooling plate 2 has three side edges 21, 22, 23, which form the sides of an imaginary isosceles triangle. The corners of the imaginary isosceles triangle are here rounded, so space is saved. In addition, eddy currents within the cooling plate 2 can be reduced by the rounded corners.

To further reduce eddy currents, a recess 8, which is formed as a slot, is provided. Here, the slot 8, which is elongated, extends from a center 800 of the cooling plate 2, in particular a center of symmetry of the cooling plate 2, to the third side edge 23 of the cooling plate 2. Furthermore, the recess 8 lies between two sections of the cooling channel 24.

The coil device 1 has three coil windings 4, which in the illustrated figure in its cross section circular are formed. Furthermore, the coil windings 4 have an end face 400 which is formed, for example, by an end face of a winding core, which is assigned to the respective coil winding 4.

The coil windings 4 are arranged symmetrically to each other. Here, the coil windings 4 an angle 41 of 2π / 3 (= 120 °) to each other. In other words, the coil windings 4 are spatially offset by the angle 41 of 2π / 3 to each other. Here, the angle 41 refers to the common center 800. In other words, the coil windings 4 are arranged substantially in the region of the rounded corners of the triangular-type cooling plate 2.

The cooling channel 24 extends at least partially along the coil windings 4. The cooling channel 24 preferably extends approximately completely along the coil windings 4. In other words, the coil windings 4 are surrounded by the cooling channel 24 up to an angle 43. Corresponding to the angle 43, the cooling channel extends at least over an angle 42 of at least 5π / 3, in particular of at least 11π / 3, more preferably of 2π about the respective coil winding 4. The angle 43 leads to a recess of an angular range of the coil winding 4, the is not surrounded by the cooling channel 24 and corresponds to the angle 43. In other words, an angle sum formed from the angle 42 and the angle 43 has the value 2π. The angle range, which corresponds to the angle 43, can be provided for an electrical contacting by means of contacting elements 10, in particular by means of a bent copper tab.

Due to the course of the cooling channel 24, a preferred heat dissipation of the coil devices 4 is advantageously made possible by means of the cooling plate 2. In addition, the mechanical stability of the coil device 1 is increased and improved by the cooling plate 2. Furthermore, by compressing the coil device 1, for example by means of the cooling plate 2, space and weight can be saved. In other words is made possible by the cooling plate 2, a compression of the coil device 1. In addition, the said compression of the cooling plate 2 with the end faces 400 of the coil devices 4 is facilitated.

FIG. 2 shows a plan view of a coil device 1 according to the invention, which is comparable to the in FIG. 1 is shown coil device. In other words, that can be under FIG. 1 Said on FIG. 2 applied and transmitted.

The coil device 1 in FIG. 2 has a T-shaped or T-shaped cooling plate 2. In addition shows FIG. 2 A more complex arrangement and extension of the cooling channel 24. This extends meandering within the cooling plate 2 to the coil devices 4. An advantage of the meandering arrangement of the cooling channel 24 is that thereby the cooling of the cooling plate 2 and thus the coil device 1 is improved. In addition, the flow 61 and the return 62 of the cooling channel 24 can be arranged in a common region of the cooling plate 2, so that their fluidic contacting is simplified.

As already in FIG. 1 includes the coil device in FIG. 2 a recess 8 which extends radially outward from a center 800. Here, a circular recess is provided within the center 800. As a result, an attachment of the cooling plate 2 on a common axis, which is provided for the arrangement of the coil devices 4, allows. Furthermore, thereby a pressing of the cooling plate 2 with the end faces 400 of the coil devices 4 is facilitated.

In FIG. 3 a further plan view of a coil device 1 according to the invention is shown. This shows FIG. 3 essentially the same elements as before FIG. 1 and or FIG. 2 ,

FIG. 3 unlike the FIGS. 1 and / or 2 a star-shaped or star-shaped cooling plate 2. Advantageously, this further space can be saved. The cooling plate 2 in turn has a cooling channel 24, which extends at least partially around the coil windings 4 of the coil devices 1. Here, the flow 61 and return 62 of the cooling channel 24 are arranged within a common area, so that their fluidic contact is facilitated and improved.

The coil device 1 has a recess 8, which is formed star-like or star-shaped. For this purpose, this has a plurality of elongated slots 81 which extend from the common center 800 in different directions. Advantageously, this significantly reduces the formation of eddy currents. One of the slots 81 is in this case arranged between the flow 61 and the return 62 of the cooling channel 24. In other words, the lead 61 and the return 62 are spaced by one of the slots 81.

The dashed lines correspond to an alternative extent of the cooling channel 24. In this case, the cooling channel 24 extends in the manner of a tab between in each case two adjacent slots 81. This advantageously improves the cooling of the coil apparatus.

Furthermore, the coil device 1 contacting elements 10, in particular copper tabs, which are arranged between the coil devices 4 and the cooling channel 24. In this case, the cooling channel 24 extends along the contacting elements 10, so that they are cooled by the cooling channel 24 or by a coolant, which is arranged within the cooling channel 24 or flows through it.

In FIG. 4 is a side sectional view of a portion of a coil device 1 according to the invention shown.

Here, one of the coil devices 4 and the cooling plate 24 can be seen in the illustrated section. On one of the coil winding 4 facing side of the cooling plate 24, an electrically insulating coating 14 is arranged or applied. This is used for electrical insulation of the cooling plate 24 with respect to the voltage-carrying components of the coil winding 4. Here, the electrical insulating material or the insulating coating 14, for example, from a little water-absorbing plastic, in particular PPS, or a ceramic, such as aluminum nitride, be formed. Furthermore, an arrangement by means of a silicone layer is advantageous because unevenness of the coil winding 4 and / or the cooling plate 24 can be compensated.

On a side facing away from the coil winding 4 of the cooling plate 2, a further electrically insulating layer or coating 16 is attached. Like the electrically insulating layer 14, it may be formed from a plastic which absorbs little water, for example PPS, or from a ceramic, for example aluminum nitrite. The further electrically insulating layer 16 is provided for electrical insulation with respect to an iron yoke 12 of the coil device 1.

Although the invention has been further illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples, or other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

Claims (15)

Coil device (1) for a power converter, comprising a cooling plate (2) and a plurality N of coil windings (4), wherein the cooling plate (2) is thermally coupled to at least one end face (400) of one of the coil windings (4), characterized arranged that the coil windings (4) spatially at an angle (41) of 2π / N offset from each other, and the cooling plate (2) a cooling channel (24) extending at least partially around each of the N coil windings (4). Coil device (1) according to claim 1, characterized in that it comprises exactly three coil windings (4). Coil device (1) according to claim 1 or 2, characterized in that the cooling channel (6) extends over an angle (42) of at least 5π / 3, in particular of at least 11π / 6, particularly preferably of 2π, around the respective coil winding (4 ). Coil device (1) according to one of the preceding claims, characterized in that the cross section of the cooling channel (24) in the region of the coil windings (4) is increased. Coil device (1) according to one of the preceding claims, characterized in that the cooling plate (2) is triangular or triangular in shape. Coil device (1) according to claim 5, characterized in that the cooling plate (2) has three side edges (21, 22, 23), wherein the cooling channel (24) along two side edges (21, 22) of the three side edges (21, 22 , 23). Coil device (1) according to one of the preceding claims, characterized in that the cooling plate (2) at least a recess (8), in particular a slot. Coil device (1) according to claim 7, characterized in that the recess (8) is star-shaped or star-shaped. Coil device (1) according to Claim 8, characterized in that the recess (8) is formed by a plurality of slots (81), the slots (81) extending in a star-like manner in different directions starting from a common center (800). Coil device (1) according to claim 9, characterized in that the cooling channel (24) extends like a lug between the slots (81). Coil device (1) according to one of the preceding claims, characterized in that the cooling plate (2) is arranged on winding cores of the coil windings (4), wherein a winding core facing side surface of the cooling plate (2) has an electrically insulating layer (14) or coating , Coil device (1) according to claim 11, characterized in that a winding core facing away from the side surface of the cooling plate (2) has an electrically insulating layer (16) or coating. Coil device (1) according to one of the preceding claims, characterized in that the cooling plate (2) made of aluminum, copper, stainless steel or copper-nickel ferrite or a mixture thereof is formed. Coil device (1) according to one of the preceding claims, characterized in that each of the coil windings (4) has a contacting element (10) for electrical contacting wherein each of the contacting elements (10) is at least partially surrounded by the cooling channel (24). Coil device (1) according to claim 14, characterized in that the contacting elements (10) are designed as copper tabs.

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