Non-uniform electrical winding

Abstract

The invention relates to an electrical winding configured to be coiled wherein said electrical winding is characterized in that it has a non-uniform geometry. An electrical winding having a non-uniform geometry is advantageous when used around a core of an electromagnetic component in that it is possible to utilize the different size of available spaces inside such core and at the periphery of such core. This may lead to a reduction of the total size of the electromagnetic component.

Description

NON-UNIFORM ELECTRICAL WINDINGField of the invention

[0001] The invention relates to an electrical winding having a non-uniform geometry, a method of manufacturing such electrical winding and the use of such electrical winding as part of an electrical coil, transformer and reactor.Background of the invention

[0002] In the art electrical windings are known and used in a whole range of various electromagnetic components such as generators, motors, transformers, reactors, solenoids, etc. Known electrical windings may be coiled around a core of ferromagnetic material. Such coil is either made of one thin electric cobber wire that is wounded around the core a plurality of times. The thickness of the wire is determined by application and is typically relatively thin when used in a generator, motor or reactor whereas it might be relatively thicker if used as a filter for voltage smoothing. Alternatively, the electrical windings of a component such as a reactor may be built of a plurality of thin cobber sheets surrounding the core.

[0003] It is known to cool such coils and thereby indirectly the individual electrical windings by positioning cooling channels between the individual windings. In this way heat generated from current conducted by these windings can be removed either directly from the winding or indirectly via heat transfer from one winding to another until removed by the coolant flowing in the cooling channel.

[0004] A problem with known electrical windings is that a reactor or transformer build based on known electrical windings is space and material consuming leading to expensive and heavy electromagnetic components. In addition, such expensive and heavy electromagnetic components generate heat which is difficult to effectively remove due to the compact geometry of traditional electrical windings. It is challenging to keep the compact design for a reactor or transformer with known electrical windings and at the same time keep it cold.Summary of the invention

[0005] The inventors have identified the above-mentioned problems and challenges related to cooling, size and price of electromagnetic components and solved these problems by the present invention as described below.

[0006] In an aspect, the invention relates to an electrical winding configured to be coiled wherein said electrical winding is characterized in that it has a non-uniform geometry.

[0007] This is advantageous in the it has the effect that one part such as the centre part of a coiled electrical winding is thinner than an periphery part of the electrical winding leading to an optimized heat distribution and cooling of the electrical winding.

[0008] An electrical winding having a non-uniform geometry is advantageous when used around a core of an electromagnetic component in that it is possible to utilize the different size of available spaces inside such core and at the periphery of such core. This may lead to a reduction of the total size of the electromagnetic component.

[0009] In this context an electrical winding should be understood as an electrical conductor of an electrically conductive material that is designed to be coiled around a core. Such electrical conductor may have an outer insulating layer. Alternative, the electrical conductor may be of a non-conductive material which is coated with an electric conductive material. Thereby establishing a current path around the core and thereby providing an electromagnetically component such as a reactor or a transformer.

[0010] In this context coiled should be understood as winding into rings or spirals such as to roll or twist the electrical winding into a shape resembling a coil.

[0011] In this context geometry should be understood as a geometrical shape. In general, a geometrical shape for an electrical winding is typically seen as a cylinder but could also be a plate or sheet. The geometrical shape, of an electrical winding as a cylinder, has a uniform geometry all along the length of the electrical winding. There might be small changes or variants in the diameter / cross-sectional area of the cylinderalong the length of the cylinder, but it is still considered a geometrical shaped cylinder. The scale of the small changes or variants of the geometrical shape would be in the size of non-visible to the human eye, which could typically occur from differences in a production.

[0012] An example of a non-uniform geometry should be understood as a non- uniform geometrical shape, where the geometrical shape is the same all along the electrical winding, but the size of the geometrical shape changes. The changes in size of geometrical shape are in a range that is visible to the human eye. These changes could be for an electrical winding which has a geometrical shape as a cylinder, where the cylinder changes in diameter / cross-sectional area during the length of the electrical winding.

[0013] In another example, a non-uniform geometry should be understood as a non- uniform geometrical shape, where the geometrical shape changes from one geometrical shape to another geometrical shape. The geometrical shape could change from e.g., a cylinder to a cuboid form or to a geometrical shape that splits of into a plurality of branches. The non-uniform geometry could change one or more times along the length of the electrical winding and could go back and forth between two or more geometrical shapes along the length of the electrical winding.

[0014] In an exemplary embodiment of the invention said electrical winding is of an electrically conductive material.

[0015] In an exemplary embodiment of the invention, said electrical winding is of a non-electrically conductive material, wherein said non-electrically conductive material is covered by an electrically conductive material.

[0016] This is advantageous in that it has the effect, that production of the electrical winding is cheaper that production thereof in a conductive material. Further, this is advantageous in that an electrical winding of a non-electrically conductive material such as a polymer is more flexible that one of a conductive material such as aluminium or cobber.

[0017] In an exemplary embodiment of the invention, said electrical winding is a liquid electrically conductive material provided in a shell.

[0018] In an exemplary embodiment of the invention, said shell is manufactured by an additive manufacturing process in a non-electrically conductive material.

[0019] Liquid (or gaseous) electrically conductive material in a non-conductive shell is advantageous in that it has the effect, that the liquid electrically conductive material can be used as coolant. This means that the liquid electrically conductive material can be circulated in and out of the non-conducive shell and thereby conduct heat from the conductor to the outside of the conductor such as to a heat exchanger of a cooling system. Thus, the coolant is then becoming the electrical conductor (or vice versa). The pump used in such cooling system to pump should preferably be an electromagnetic pump.

[0020] A non-limiting example of a liquid electrically conductive material is Gallium which has phase shift at 30°C i.e. be regulating the temperature above and under this temperature, such electrical conductor may change from a solid electrical conductor to a liquid electrical conductor. By conducting current through such Gallium conductor its temperature may start to increase and when above 30°C it change state to liquid and thus may start to be circulated to keep temperature down

[0021] The non-electrically conductive material may be of a cheap plastic material and thus the shell part may be cheap and easy to manufacture and transport.

[0022] In an exemplary embodiment of the invention, said electrical winding comprises a cooling channel.

[0023] This is advantageous in that it has the effect, that cooling of the electrical winding is optimized and thus improve the current conduction capacity of the electrical winding. Further, ambient temperature is reduced in that heat emitted from the electrical winding is reduced / lowered. Hence, if the electrical winding is used in an electric panel or other enclosure, a cooling system of such enclosure can be reducedi.e. a reduction in price of such cooling system and energy used to operate such cooling system is obtained.

[0024] Further in relation to mounting and service this is advantage in that weight is reduced i.e. the platform structure next to the panel in which a reactor or transformer with winding of the present invention is mounted does not need to be extra supported. This is because the weight is reduced so much that the standard dimensioning is sufficient to carry the weight of the reactor or transformer.

[0025] In an exemplary embodiment of the invention, said electrical winding has a first and a second ends.

[0026] It should be noted that an electrical winding according to the present invention may include three or more ends for connecting the electrical winding to one or more different components.

[0027] In an exemplary embodiment of the invention, said first and second ends has terminal connections.

[0028] Having first and second ends with terminals is advantageous in that the electrical winding can be lead current from one connected component to another connected component.

[0029] In an exemplary embodiment of the invention, an electrical component and said electrical winding are monolithic.

[0030] Forming the electrical winding and an electric component in one / as one structure is advantageous in that the electrical winding do not need any end / terminals for connection to the electric component.

[0031] In an exemplary embodiment of the invention, a cross-sectional area of said electrical winding is between 0,1mm and 100mm, preferably between 0,2mm and 50mm, most preferably between 0,3mm and 10mm.

[0032] The limit of cross-sectional area is in principle what is possible to manufacture by an additive manufacturing process. Note that cross-sectional area should here be understood as the cross-sectional areas of the conductor branches.

[0033] In an exemplary embodiment of the invention, said electrical winding comprises a clips.

[0034] A clips is advantageous in that in this way e.g. a cooling pipe can be attached easy and exactly where it is needed for optimal cooling.

[0035] In an exemplary embodiment of the invention, said electrical winding comprises an inner part and an outer part, wherein a diameter of said inner part is smaller than the diameter of said outer part.

[0036] In this context inner part should be understood as the part of the electrical winding which is surrounded by a core. In case a plurality of electrical windings exists the inner part of such plurality of windings are the parts that are facing each other.

[0037] In this context outer part should be understood as the part of the electrical winding which is opposite of the inner part i.e. not surrounded by a core.

[0038] It is advantageous to have an outer part with a diameter that is bigger than the diameter of the inner part. A bigger diameter leading to a better heat dissipation. Further, heat generated in the inner part can propagate to the outer part of the electrical winding and thereby facilitating heat to easily dissipate from the inner part to the surroundings.

[0039] In this context diameter should be understood as the physical measurable diameter. Hence, there is no need to cut or calculated the diameter, it can simply be measured directly with a caliper.

[0040] In an exemplary embodiment of the invention, said inner part and said outer part are monolithic.

[0041] This is advantageous in that the electrical winding is one part or structure, No joints or connections are needed to establish the coiled electrical winding and thereby electrical losses are reduced in an electrical winding according to the present invention.

[0042] Thus, a monolithic electrical winding may include a coiled part and one or more ends in one and the same piece / structure without having to physically connect two or more elements. Thereby the manufacturing of the electrical winding can be done in one process step i.e. an additive manufacturing step.

[0043] In an exemplary embodiment of the invention, said inner part of the electrical winding is massive.

[0044] This is advantageous in that a high current can be conducted in a limited physical area.

[0045] In an exemplary embodiment of the invention, said inner part comprises an inner cooling channel.

[0046] This is advantageous in that conducting high current in a limited aera will generate heat which can be removed by a flow of coolant in a cooling channel.

[0047] In an exemplary embodiment of the invention, said inner cooling channel comprises an inner cooling channel inlet and an inner cooling channel outlet.

[0048] It is advantageous to cool the inner part of electrical winding in that the main part of heat generated by the electrical winding is generated at the inner part. Especially, a cooing channel inside the inner part is advantageous in that cooling is applied directly where heat is generated.

[0049] In case of a plurality of electrical windings each of the inner parts of these windings may have cooling channels and thus the inlet and outlets hereof may be connected in series.

[0050] In an exemplary embodiment of the invention, said outer part of said electrical winding comprises a geometry which is comprised by the list comprising: bionic, web, sponge and honeycomb.

[0051] Such geometry of the outer part is advantageous in that when one of the above-mentioned geometries are chosen, the amount of material used for the electrical winding is reduced. It is also an advantage that the surface of such geometries of the electrical winding is increased in that more surface is then available for cooling.

[0052] For all the bionic, web, sponge, honeycomb like geometries these structures, are good for cooling down the electrical winding. The geometries all comprise less material with a big surface, so the smaller amount of material is easier to cool down and provides a more compact geometry / electrical winding.

[0053] In an exemplary embodiment of the invention, said electrical winding comprises intersection points.

[0054] This is advantageous in that it is possible to design an electrical winding with a broad variety of geometries.

[0055] In an exemplary embodiment of the invention, said electrical winding comprises airgaps.

[0056] This is advantageous in that it is possible to design an electrical winding with improved cooling properties.

[0057] In an exemplary embodiment of the invention, at least one current path branches off through said electrical winding.

[0058] This is advantageous in that it has the effect that not all current need to be conducted along one path through the electrical winding. Thereby spacing of electrical conductors are facilitated leading to an optimized cooling of the electrical winding.

[0059] Further, allowing a current path to branch one or more times along the longitudinal direction of the electrical winding is advantageous in that it has the effect,that the geometry of the electrical winding can be changed compared to traditional massive electrical windings. A change in geometry allows the electrical winding to take advantage of the fact, that the space outside the core is much larger than the space inside the core.

[0060] Further, the electrical winding can be made self-supported or part of a support structure for other components, the surface areas is increased leading to better cooling and optimized according to skin-effect at high frequencies, etc.

[0061] In an exemplary embodiment of the invention, said geometry is configured to provide multiple current paths through said electrical winding.

[0062] Multiple current paths should with respect to an electrical winding of the present invention be understood as the current path from the inner part of the winding is branches off into two or more current paths through the outer part of the winding. This may be repeated for each winding i.e. in each inner part multiple current paths may join as one current path which may branch off to two or more current paths in the outer current path. These two or more current paths may then join to one current path in the subsequent inner part and so on through out the electrical winding.

[0063] With this said, it should be mentioned, that not all windings may be identical hence the inner part of one winding may comprise one current path and the inner part of a second winding may have two or more current paths. In the same way the outer part of one winding may have one current path and the outer part of another winding may have a plurality of current paths.

[0064] In an exemplary embodiment of the invention, said electrical winding is a first electrical winding which is connected in series to a second electrical winding wherein said second electrical winding is an electrical winding according to any of the preceding claims.

[0065] Connecting two or more electrical windings according to the present invention is advantageous in that together they are forming a coil.

[0066] Two or more non-uniform electrical windings may be provided in series and thereby establish a common current path through these two or more windings is established. Such two or more current paths may together be referred to as a coil. Hence, such coil made of electrical windings of the present invention is having the advantages described above in relation to a single electric winding.

[0067] The general advantages of a coil such as increasing the inductance of the coil by adding more electrical windings is known to the skilled person and will not be described in further details.

[0068] In an exemplary embodiment of the invention, said first electrical winding comprises a first end and said second electrical winging comprises a second end.

[0069] In an exemplary embodiment of the invention, said first electrical winding comprises a first terminal connection, said second electrical winding comprises a second terminal connection and wherein said first and second electrical winding are connected with one or more intermediate electric windings.

[0070] In an exemplary embodiment of the invention, said electrical winding is coiled around a core.

[0071] In an exemplary embodiment of the invention, said core is made of air or a ferromagnetic material.

[0072] In an exemplary embodiment of the invention, said core is closed.

[0073] In an exemplary embodiment of the invention, said core comprises two or more core parts.

[0074] This is advantageous in that it has the effect, that a pre-manufactured coil can be mounted around the core. The coil may be mounted around the first core-leg and thus the second core-leg may be used to connect a first and second end of the first coreleg thereby establishing a closed core.

[0075] A first core-leg may be referred to as the core and a second core-leg may be referred to as a connection part.

[0076] In an exemplary embodiment of the invention, said core (16) comprises a cooling channel.

[0077] This is advantageous in that it has the effect that it is possible to cool the core directly at the position where most heat is generated by allowing a flow of a cooling fluid through the inside of the core.

[0078] In an exemplary embodiment of the invention, said core is made of a ferrofluid provided in a shell.

[0079] In an exemplary embodiment of the invention, said shell is manufactured by an additive manufacturing process in a non-electrically conductive material.

[0080] As described above regarding the liquid electrical conductor, the liquid core is advantages in that it may also be used as core and coolant (i.e. cooling fluid) at the same time. Thus, circulated in a cooling system and thereby removing heat from the core / reactor.

[0081] In an exemplary embodiment of the invention, said inner cooling channel is fluidly connected to a cooling unit.

[0082] This is advantageous in that a liquid (or gaseous) refrigerant can flow through the inside of the electrical winding.

[0083] In an exemplary embodiment of the invention, said outer cooling channel is fluidly connected to a cooling unit.

[0084] This is advantageous in that a gaseous refrigerant (such as air) can flow through the outside cooling channel of the electrical winding.

[0085] In an exemplary embodiment of the invention, said core is fluidly connected to a cooling unit.

[0086] This is advantageous in that a liquid (or gaseous) refrigerant can flow through the inside of the core.

[0087] It should be noted that the cooling unit connected to inner cooling channel, outer cooling channel and the core may be one and the same cooing unit.

[0088] In an exemplary embodiment of the invention, said cooling unit is heat exchanger or fan.

[0089] In an exemplary embodiment of the invention, said cooling unit is a combination of heat exchanger and fan.

[0090] In an exemplary embodiment of the invention, said cooling unit generates a flow of air through said outer cooling channel.

[0091] In an exemplary embodiment of the invention, said flow of air is guided by an air guide.

[0092] An air guide is advantageous in that a flow of cooling air can be directed to a desired part of the outer (or inner) winding so at to provide an optimal cooling of the winding.

[0093] In an exemplary embodiment of the invention, said air guide is said insulation material.

[0094] In an exemplary embodiment of the invention, said cooling unit (18) is fluidly connected to said inner cooling channels.

[0095] In an exemplary embodiment of the invention, said cooling unit (18) is fluidly connected to said cooling channels of said core.

[0096] It is advantageous to cool down electrical windings to have a better conductance and to extend the lifetime of the electrical windings.

[0097] The cooling unit could either be a fan or a heat exchanger depending on the size and placement of the cooling unit.

[0098] It should be noted that a liquid refrigerant used to cool in the inner cooling channel of the winding is preferably a non-conductive refrigerant.

[0099] In an aspect, the invention relates to an electrical winding according to any of the preceding claims wherein said electrical winding is at least partly manufactured by additive manufacturing.

[0100] In an aspect, the invention relates to a transformer comprising a plurality of electrical windings according to any of the preceding claims, wherein said plurality of electrical windings are coiled around said core.

[0101] Such transformer is advantageous in that material and size can be reduced compared to traditional transformers.

[0102] In an aspect, the invention relates to a reactor comprising a plurality of electrical windings according to any of the preceding claims, wherein said plurality of electrical windings are coiled around said core.

[0103] Such reactor is advantageous in that material and size can be reduced compared to traditional reactors.

[0104] In an aspect, the invention relates to a coil comprising two or more electrical windings according to any of the preceding claims.

[0105] In an exemplary embodiment of the invention, said two or more electrical windings are all identical.

[0106] It should be mentioned that identical should be understood as all or at least part of the non-uniform electrical windings are identical i.e. having the same geometry. Note that the two or more electrical windings may individually be referred to as first, second and intermediate electrical windings.

[0107] In an exemplary embodiment of the invention, said two or more electrical windings are non-identical.

[0108] Non-identical should here be understood as two or more of the plurality of the non-uniform electrical windings are of different geometry. Hence, in principle none of the plurality of the non-uniform electrical windings may be identical.

[0109] Non-identical should be understood as two or more of the electrical windings may be of the same design such as a bionic or web design, but where the individual windings of such design are not identical. An example of a design which is considered to have windings of the same geometry, is a bionic design. However, a bionic design may be computer generated and even based on the same input, two subsequent windings of a bionic design may not be completely identical i.e. could be said to be variant of the same design.

[0110] In an exemplary embodiment of the invention, two neighbouring electrical windings of said two or more electrical windings are spaced apart be a distance.

[0111] Insulating the individual windings by a distance such as by having an airgap separating two windings is advantageous to maintain the number of electrical windings, in case of two windings are in contact they will only count as one winding and thus reduce the effect of the coil.

[0112] In an exemplary embodiment of the invention, said distance between two neighbouring electrical windings varies.

[0113] An example of varying distances could be that a distance measured at an inner part is larger than a distance measured at said outer part.

[0114] It should be noted that the distance between a first set of neighbouring windings may not be the same as between a second set of neighbouring windings.

[0115] In an exemplary embodiment of the invention, said distance is below 25mm, preferably below 15mm, preferably below 10mm

[0116] Keep the distance between two windings as small as possible is advantageous to exploit the available space around the outer part best possible.

[0117] It should be mentioned that this distance is measured where to windings are closest to each other. Hence, it should be understood that the distance between two windings may wary.

[0118] In an exemplary embodiment of the invention, an insulation material is placed between two or more neighbouring electrical windings.

[0119] In an exemplary embodiment of the invention, said insulation material is one selected from the list comprising: a sheet material, an applied material or a structure manufactured by additive manufacturing.

[0120] It is advantageous to place an insulation material between two neighbouring electrical windings to ensure that these two electrical windings are not getting in contact and thereby having the effect of each of the two electrical winding.

[0121] The insulation material can both be a sheet material placed in between two electrical windings. It could also be a coating which is coated over the electrical winding to insulate the windings from each other. Such coating could be applied e.g. by spray, dipping, or the like. Another way to insulate the neighbouring electrical windings could be with a piece of material or a structure which could be placed between the electrical windings, where such material or structure is produced by additive manufacturing.

[0122] It is important to insulate each electrical winding from each other by air or material as described above to ensure to have the effect of each electrical winding around the core.

[0123] In an aspect, the invention relates to a core around which an electrical winding according to any of the preceding claims are coiled, wherein said core comprises a cooling channel.

[0124] In an exemplary embodiment of the invention, said core comprises a cooling channel inlet and a cooling channel outlet.

[0125] In an exemplary embodiment of the invention, said core is at least partly manufactured by additive manufacturing

[0126] In an aspect, the invention relates to a method for connecting a first end (3) of a coil comprising a plurality electrical windings to a second end of said coil, the method comprising the steps of: monolithically uniting said first end and a first electrical winding of said plurality of electrical windings via an additive manufacturing process, monolithically uniting one or more additional electrical windings to said first electrical winding via said additive manufacturing process so as to establish said coil, and monolithically uniting said second end and a second electrical winding of said plurality of electrical windings via said additive manufacturing process.

[0127] In an exemplary embodiment of the invention, at least one of said plurality of electrical windings has a non-uniform geometry.The drawings

[0128] For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts. The drawings illustrate embodiment of the invention and elements of different drawings can be combined within the scope of the invention:FIG. la illustrates an electrical winding,FIG. lb illustrates a coil,FIG. 2a illustrates an electrical winding, FIG. 2b illustrates a coil,FIG. 3 illustrates a reactor,FIG. 4a illustrates a reactor with ventilation,FIG. 4b illustrates an exploded view of a reactor with ventilation, andFIG. 5 illustrates a method.Detailed description

[0129] The present invention is described in view of exemplary embodiments only intended to illustrate the principles and implementation of the present invention. The skilled person will be able to provide several embodiments within the scope of the claims.

[0130] The electrical winding of the present invention is designed so that along its length I.e. following the current path from a first end 3 to a second 4 has a non-unform geometry. Non-uniform geometry should be understood as to parts of the electrical winding that has a geometry that is different. Different should be understood two different shapes (one conductor vs a plurality of conductors or one cylinder vs mesh / web-like structure, etc.), two different diameters, two different cross-sectional areas, etc. Found / measured along the length of the winding 1. it should be mentioned, that production variation is not considered falling within the term non-uniform geometry.

[0131] Fig. la illustrates an electrical winding 1 having a non-uniform geometry according to an embodiment of the present invention having a first end 3 and a second end 4. The electrical winding 1 (also referred to simply as winding) may be connected in series with additional electrical windings 1 which may have a uniform or non- uniform geometry. Thus, the one winding 1 illustrated in fig. la could be considered as one winding of a helical coil structure such as the one illustrated e.g. in fig. lb and 2b.

[0132] The winding 1 illustrated in fig. la is surrounding / coiled around an air core 16 which is indicated between the two stipulated lines. Of course, in other embodiments, the winding is coiled around a core 16 of a ferromagnetic material.

[0133] The electrical winding 1 comprises an inner part 8 and an outer part 9. The geometry of the inner part is different from the geometry of the outer part. This is to be able to exploit the ambient area at the outer side of the core which is larger than the ambient area of the inner side of the core. More specifically, in theory the outside of the core adjoins an infinite space, part of which can be filled up with the outer part 9. In contrary, the inner part 8 adjoins a finite space, at least when the core is a closedcore, thus there is a limited space for the geometry of the inner part before it is limited by the opposing part of the core. Hence, the geometry of the outer part can be designed with the purpose of heat dissipation whereas the geometry of the inner part can be designed with the purpose of exploiting the limited space inside the closed core. This is especially advantageous in an embodiment where several electrical windings are connected in series as illustrated e.g. in fig. lb and 2b.

[0134] The inner part 8 of the single winding 1 illustrated in fig. la comprises first end 3 and the second end 4 which may both comprise a terminal connection. It should be mentioned, that not illustrated ends e.g. with terminal connections may be comprised by the outer part 9.

[0135] The winding 1 illustrated in fig. la is having a non-uniform geometry according to an embodiment of the present invention. It has a diameter (could also be referred to as cross-sectional area) dl of the geometry of the inner part and a diameter d2 (could also be referred to as width between point C and D) of the geometry of the outer part, where the outer diameter d2 is greater than the inner diameter dl . The cross- sectional area of the inner geometry dl is defined as the cross-sectional area of the electrical winding 1 at the inner part 8, where the diameter of the outer geometry d2 is defined as the width of the electrical winding 1 at the outer part 9. This geometry is one example of an outer part exploiting the huge heat dissipating potential available at the outer part 9 (compared to the same for the inner part).

[0136] Alternative geometries exists and just to mention a few these alternatives include oval, box-like, spiral, geometries comprising a plurality of conductors that are spaced apart, perforated or non-perforated surfaces, etc.

[0137] The first end 3 of the illustrated winding may as mentioned comprise a terminal connection via which the winding is connectable to an electrical component such as an electrical conductor that is connecting the winding to other electrical components. The second end 4 may also comprise a terminal connection. If not, it may monolithically be connected to a not illustrated component such as an electrical winding having a uniform or non-uniform geometry. Monloithically united elementsor parts may be joint by interior shaped corners facilitating the optimal current path for conducting current. A terminal connection 5 is illustrated in fig. lb.

[0138] In an embodiment, the winding is designed to accommodate fastening of an external cooling conductor such as a flexible pipe. Such fastening may be accommodated by printing clips as part of the winding. Hence, in this way a cooling pipe is fast to mount at the exact position where cooling is needed.

[0139] The geometry of the winding 1 illustrated in fig. la has a uniform surface that is not perforated. The winding may be massive or it may comprise a cooling channel extending at least partly through the inner and outer parts of the winding between the two ends 3, 4. Such cooling channel is following the winding and thus coiled around the core and may start and stop anywhere along the length of the winding i.e. both at the inner and outer part of the winding.

[0140] The cooling channel may also have a non-uniform geometry i.e. it may be implemented as one channel having a first cross-sectional area in the inner part 8 and one channel having a second cross-sectional area in the outer part 9. In the outer part it may branch off to several individually connected channels which towards a subsequent inner part it may re-join into one channel. Of course, alternative geometries and designs of such cooling channel exist.

[0141] In the embodiment where the winding comprises a cooling channel, this cooling channel may include an inlet and an outlet. The inlet may be provided at the first end 3 and the outlet may be provided at the second end 4. Alternatively, or in addition one or more an additional set of inlet and outlet may be provided along the winding. As a non-limiting example, the outer part of one single winding may comprise both an additional inlet and an additional outlet for connecting to a heat exchanger / cooling circuit. In this way the temperature of the coolant flowing in the cooling channel can be reduced part of the way through the cooling channel.

[0142] Accordingly, an electrical conductor such as the electrical winding 1 illustrated in fig. la and lb comprises or is part of an electrical conductors / electrical winding cooling system that increases the heat transfer from the electrical conductor / winding compared to known methods of cooling electrical conductors / windings. The efficiency is increased by integrating cooling channels into the design of the inner and / or outer parts of the electrical winding.

[0143] It should be mentioned that not all inner or outer parts may have cooling channels hence in an embodiment every second winding may have an inner cooling channel and a outer cooling channel adapted to conduct a liquid refrigerant.

[0144] Fig. lb illustrates an embodiment of the invention comprising a plurality of series connected electrical windings la- In of the type illustrated in fig. la. The illustrated series connected windings are forming a helical coil 13 around an air core 16. The winding 1 comprises to ends 3, 4 each having terminal connections 5 of which only one is visible. The individual windings are separated by a distance denoted 14.

[0145] The electrical winding 1 illustrated in fig. 2a is conceptually similar to the winding 1 illustrated in fig. la i.e. designed with a geometry that is non-uniform such as having a cross-sectional area / a geometry at the inner part that is different form the cross-sectional area / geometry of the outer part. The difference is that the winding 1 illustrated in fig. 2a comprises a perforated surface which may also be referred to as a spongy, web-like, bionic, mesh or similar design.

[0146] The winding 1 is having an outer part 9, where the outer part 9 is designed with conductor branches in a web-like / bionic geometry. The web-like geometry is branched out from the first end 3 of the inner part 8 through the outer part 9 to the second end 4 of the inner part 8. The conductor branches 22 of the web-like geometry meets in intersection points 6 in the outer part 9 and thereby creating airgaps 7 in the web-like structure. In this way, the web structured geometry provided by the conductor branches 22 creates a current path 12 between the first end 3 and the second end 4. The current path 12 in the inner part 8 consist of only one individual current path whereas the current path 12 in the outer part 9 consist of a plurality of individual current paths 12’.

[0147] The current path 12 follows the structure of the electrical winding 1, where the current path 12 could branch out from the first end 3, follow one or more individualcurrent path 12’ through the outer part 9 and the return in one joined branch 22 at the second end 4 as illustrated in fig. 2a.

[0148] The embodiment of the invention illustrated in fig. 2a shows an outer cooling channel integrated in the designed geometry. This cooling channel is established and located partly inside of the web-like geometry of the outer part 9 as airgaps 7. The airgaps 7 allows air to flow through the outer part and thereby provide a very efficient cooling thereof. In this way the plurality of airgaps 7 together is providing the outer cooling channel of the electrical winding.

[0149] It should be mentioned that this outer cooling channel may be combined with an inner cooling channel provided inside the inner part 8 of the winding. Such inner cooling channel may have coolant inlet and outlet in the winding before the current path 12 branches off in two or more conductor branches 22.

[0150] It should be noted that the design illustrated in fig. 2a may also comprise a closed cooling channel as described above provided all the way through the winding 1 allowing the winding to be cooled both by air (e.g. from a fan) and from a liquid or gaseous coolant in such closed cooling channel

[0151] Accordingly, an electrical winding 1 according to the present invention is non-uniform at least because of one of the following:- the geometry of the inner part 8 (e.g. cylindrical) is different from the geometry of the outer part 9 (e.g. spongy),- the diameter dl is different from the diameter d2,- the geometry of the inner part 8 comprise one conductor branch 22 allowing one current path 12 and the geometry of the outer part may comprise a plurality of conductor branches 22 allowing for a plurality of current paths 12’, o this plurality of current paths 12’ / conductor branches may be space apart in space with airgaps 7, andthe cross section of the current path 12 (conductor branch) of the inner part is different from the sum of cross sections of the individual current paths 12’ (conductor branches) of the outer part,- the amount of material used to build the inner part 8 is different from the amount of material used to build the outer part 9,- the inner part 8 may comprises an inner cooling channel 2a for liquid cooling and the outer part 9 may only be cooled by air,- the inner part 8 may comprise terminal connections, where the outer part may not comprise terminal connections.

[0152] The non-uniform geometry of the electrical winding 1 illustrated in fig. 2a is non-uniform in that it comprises an inner part 8 which has a first geometry and an outer part 9 which has a second geometry.

[0153] The geometry of the inner part 8 in this particular embodiment is illustrated as a cylindrical conductor comparable to a traditional electric conductor. This cylindrical conductor is having a cross-sectional area cl. Thus, one current path 12 is provided into the electrical winding 1 at the first end 3, through conductor branches 22 of the outer part 9 and out of the electrical winding 1 at the second end 4. Hence, the one current path 12 / conductor branch 22 and the geometry of the inner part 8 are the same and having a cross-sectional area of cl.

[0154] It should be mentioned that the inner parts 8 of two electrically connected winding does not have to be identical.

[0155] Th e geometry of the outer part 9 in this particular embodiment is illustrated as a spongy geometry. This geometry is different from the cylindrical conductor geometry of the inner part 8. Accordingly, the one current path 12 from the first end 3 of the inner part 8 is branching off into a plurality of current paths 12’ of a plurality of conductor branches 22 of the outer part 9 and unites again into one current path 12 towards the second end 4. In this design, the sum of cross-sectional areas of the individual current paths is different (larger or smaller) from the cross-section area cl.

[0156] It should be noted that the geometry may also sometimes be referred to as design or structure. The geometry of the winding 1 illustrated in fig. 2a is only one example of a geometry which could be referred to as spongy or bionic. Hence, other geometries could be designed as a web, flat, squares, cylindrical, honeycomb, triangular, etc. i.e. from one geometry of the winding at the inner part 8 change or branching off into another geometry at the outer part 9. On top of that, within each of these different designs, an almost infinite number of variants are available i.e. how the individual current parts 12’ / conductor branches 22 are shaping the geometry. This includes multi-layer design, twisted design, etc. This variety is best illustrated with fig. 2b where a plurality of windings is illustrated each having a spongy design but wherein not one of the individual illustrated windings are identical (they could be though).

[0157] As illustrated, the inner part 8 and the outer part 9 are formed in one and the same structure i.e. they are monolithically united meaning that the cylindrical inner part 8 gradually branches off into the spongy outer part 9. Hence, the current path 12 of the inner part 8 gradually also branches off into the plurality of current paths 12’ of the outer part 9. Such design is possible to provide by building the winding 1 by an additive manufacturing process i.e. building the winding layer by layer in the desired geometry.

[0158] The gradual transition from the inner part 8 to the outer part 9 makes it difficult to point to an exact location of the winding where the inner part 8 stops and the outer part 9 begins and vice versa.

[0159] One way to define this may be with reference to the core 16. Hence, e.g. the center, inner or outer part of the core may define a line, which may be perpendicular to the winding 1, which can be used to separate the inner part from the outer part.

[0160] Another way to define this may be with reference to the current path 12. Hence, where the current path 12 branch off into induvial current paths 12’ may define the point where the inner part 8 stop and the outer part 9 start. Similarly, where the individual current paths 12’ unit to one current path 12 may define the point where the outer part 9 stop and the inner part 8 start.

[0161] The electrically conductive material of which the winding is made is able to transfer heat from the inner part to the outer part. In this way, heat is transferred from the hottest part of the winding to the large surface of the outer part which is optimized for cooling and thereby reducing a risk of overheating the winding / enabling conduction of higher current with smaller winding compared to traditional windings. Hence, a very efficient winding with respect to heat transfer and heat dissipation is presented in this document.

[0162] The diameter / width d2 of the geometry of the outer part 9 may be measured between points C and D (see fig. la). Note at fig. 2a that the diameter / width d2 of the geometry of the outer part 9 is different from the diameter / cross-sectional area d’ of the individual conductor branches through the outer part 9. In fact, it should be noted that the diameter / cross-sectional area d’ of two of the individual conductor branches are different.

[0163] Preferably, the cross-sectional area cl of the geometry of the inner part 8 is smaller than the diameter / width d2 of the outer part 9. In this way it is possible to utilise the space available on the outer side of a core 16 compared to the center (inner side) of the core 16. By utilise should be understood providing a larger surface for the winding 1 which is advantageous in that heat exchange with surroundings is optimized. This again led to a reduces temperature of the winding 1 which thereby is able to conduct a higher current compared to a known winding of the same material of the same amount of material.

[0164] Fig. 2b illustrates seven electrical windings 1 having a non-uniform geometry according to an embodiment of the present invention, where the seven electrical windings la- In are connected in a series, where the second end 4a of a first winding la is monolithically connected to a first end 3b of a second winding lb, and the second end 4b are connected to the first end 3c to a third winding 1c and so on. The plurality of windings 1 are connected to form a coil 13, where the coil 13 is air coil i.e. no coiled around e.g. an iron core in this embodiment of the invention.

[0165] The electrical windings la-ln in fig. 2b could be identical in an embodiment of the invention, but in this embodiment of the invention the electrical windings are designed with the same non-uniform geometry (cylindrical inner part and web-like outer part). However, even though the geometry of the windings la-ln is identical, the conductor branches 22 forming the web-like outer part may not be identical (as is the case in the design illustrated in fig. 2b if one look carefully). Another example hereof is the windings illustrated in fig. la and 2a which have the same geometry but having different or non-identical outer parts.

[0166] This may be intentionally determined by a designer using a 3D CAD software to design the windings 1 or it may be due to a computer algorithm generating the structure of the electrical windings la-ln in a CAD (CAD; Computer Aided Desing) software program based on input from the designer.

[0167] In another embodiment of the invention the electrical windings la-n of the coil 13 are not identical due to a different geometry of the individual windings la-ln. One of a plurality of examples hereof could be one winding as illustrated in fig. la, a subsequent winding having a cylindrical inner part with one diameter and a cylindrical outer part with a second diameter larger than the first diameter or a plurality of cylindrical conductor branches each having a third diameter less than the first diameter.

[0168] The embodiment of the invention shown in fig. 2b could comprise an inner cooling channel 2a, which is located inside the electrical winding 1 in the inner part 8 (indicated by dotted lines). The inner cooling channel 2a comprises an inner cooling channel inlet 10 and an inner cooling channel outlet 11, which is configured to guide a cooling fluid through the inner cooling channel 2a to cool the electrical winding 1. This cooling fluid and the cooling channel 2a may be part of a closed cooling system comprising a heat exchanger for keeping the cooling fluid at a desired temperature.

[0169] Two windings 1 should be spaced apart to work proper. The distance 14 with which two neighbouring electrical windings are spaced apart is also illustrated in fig. 2b. This distance is necessary so that no electrical windings 1 touch each other exceptfor the part, where a first 3 and second 4 end of two neighbouring electrical windings are connected (preferably monolithically connected). The distance between two neighbouring electrical windings 14 may be reduced if an insulating material other than air is positioned therebetween (see e.g. fig. 4).

[0170] The coil 13 comprises terminal connections 5, where in this embodiment of the invention a first terminal connection 5a is connected to a first end 3a of a first electrical winding la and the second terminal connection 5b is connected to a second end 4n of the last electrical winding In.

[0171] Accordingly, the electric winding 1 may comprise one first conductor branch that may branch off to a plurality of second conductor branches, each of these second conductor branches may further branch off to a plurality of third conductor branches and so on through the winding 1. In this way, following the direction of the current flow through the winding 1 from a first end to a second end, current is allowed to flow in the first conductor branch, then allowed to divide into a flow in the second conductor branches and again allowed to divide into a flow in the third conductor branches and so on into additional nthconductor branches.

[0172] In an embodiment, if current is flowing from a first end to a second end, the first conductor branch may have a first cross-sectional area, the second conductor branches may have a second cross-sectional area which is smaller than the first crosssection area. Following, the third conductor branches may have a cross-sectional area smaller than the second cross-sectional area. Accordingly, the cross-sectional area of the conductor branches may be varied in size in the longitudinal / current flow direction of the winding.

[0173] As described above, the conductor branches of the electric winding may branch off into a plurality of additional (nth) conductors. In the same way, the conductor branches may also converge from a higher number of conductor branches into a lower number of conductor branches.

[0174] It should be mentioned that a cross-sectional area of the winding at one distance from a first end may be the same as a cross-sectional area of the winding at asecond distance from the first end while the number of conductor branches at the first distance is different from the number of conductor branches at the second distance.

[0175] Further, it should be mentioned that the cross-sectional area of the winding at the first and second distances from a first end may be different while the number of conductor branches may be the same. Of course, the cross-sectional area and the number of conductor branches may also be the same at the first and second distances from the first end.

[0176] It should be mentioned that embodiment of the electrical winding may also include designs where the conductor branches branch off from the first end to a plurality of conductor branches and converge again into the second end without branching off between the first and second ends.

[0177] Fig. 3 shows another embodiment of the invention, where a coil 13 is coiled around a core 16 of a ferromagnetic material. The ferromagnetic core 16 in this embodiment of the invention is a closed core. The inner part 8 of the electrical windings are inside the ferromagnetic core 16 and the outer part 9 of the electrical windings are placed on the outside of the core 16.

[0178] The core 16 illustrated in fig. 3 comprises a first core part 16a and a second core part 16b, where the first core part 16a is a loop and the second part 16b connects the two ends of the loop from the first core part 16a to make the core 16 a closed core. The design of the loop for the first core part 16a may be configured to be guided into air core 16 of the coil 13. This could be done after both the coil 13 and the first core part 16a has been manufactured by additive manufacturing such as 3D printed, or the coil 13 could be printed around the first core part 16a. The coil 13 with the first core part 16 is open and the core could be closed by connecting the second core part 16b to both ends of the first core part 16a. It would also be possible to print the coil 13 around a core 16 directly.

[0179] In other embodiments of the invention the first and second core part 16a, 16b could be used for a core design e.g., as a square-frame, oval or circularly shaped core. The core design could also comprise an additional core part not illustrated, which fora square-framed core could be an additional core part in the middle, which divides the square-frame into two square-frames. The additional core part could also have a coil 13 comprising windings 1 as described above coiled around it.

[0180] With respect to the magnetic field a closed core is optimal and with respect to windings a straight solenoid design is optimal. As these do not match a compromise must be made to provide the optimal reactor / transformer. The compromise may include two vertical core parts each with a solenoid winding where the core in at least one end but preferably in both ends are connected. Thereby, the core turns or branches off by an angular part relatively to the vertical part. The solenoid winding along the vertical core parts may be uniform, however at the angular core part (if that has an angle of 90° or less) it is preferred to have a non-uniform winding 1 according to the present invention. This is because as soon as the core bend or branch off and the coil has to follow, there is more space available at the outer part than at the inner part of the coil. And as describe din this document, at least at these parts a non-uniform winding is advantageous.

[0181] Accordingly, the core may be a square, comprising two straight parts connected with a spheric part, circular, etc. note that any of these shapes may be monolithically.

[0182] In another embodiment of the invention one or more coils 13 are coiled around the core 16. As an example hereof could be mentioned one coil on a first core part 16a and a second coil on the additional core part 16n. The one or more coils 13 could be identical with the same geometry and same number of windings, but also with different geometry and / or different number of windings. It should be mentioned, that one winding may also have one or more outputs between its two ends.

[0183] The core 16 of a ferromagnetic material could be made iron such as an iron powder which make it possible to mould / shape the core as if the core manufactured by additive manufacturing.

[0184] The ferromagnetic core 16 could comprise a cooling channel 17 built into the core, with a cooling channel inlet and a cooling channel outlet. The cooling channelinlet and the cooling channel outlet could be placed in each end of the first core part 16a as illustrated in fig 3. The cooling channel 17 could run through the entire first core part 16a from the cooling channel inlet to the cooling channel outlet. The cooling channel inlet and outlet could also be placed in other parts of the first core part 16a, so that the cooling channel 17 only runs through a part of the core 16. In another embodiment the cooling channel inlet and outlet could be placed in the second core part 16b or in the additional core and let the cooling channel 17 run through one or more core parts 16a, 16b.

[0185] An interior cooling channel 17 may extend as one conduit or branch off (and maybe meet again) in two or more conduits. In the case where a core comprises a plurality core parts one cooling channel 17 may branch off to that each of the core parts may comprise a cooling channel. The cooling channel 17 could comprise additional inlets and / or outlets along the path of the core 16 if additional cooling is needed e.g., if the cooling fluid should be changed more often to increase the cooling capacity.

[0186] The cooling channel 17 may guide a cooling fluid for cooling the core 16. The cooling fluid could be a liquid cooling fluid such as Glycol, water solutions, dielectric fluids, etc. The cooling fluid is circulated in a cooling system with a heat exchanger, where cooling conduits of the cooling system is connected to both the cooling channel inlet and cooling channel outlet. The cooling system is configured to cool the cooling fluid and to circulate the cooling fluid through the cooling system and the core 16, so that heat is transferred away from the core 16 to prevent the core 16 from overheating.

[0187] Transformers and reactors are magnetic components which can be based on magnetic cores or core-less (air-inductors). A single winding inductor only exhibits self-inductance, and may be referred to as a reactor. When two or more windings are magnetically coupled (through a magnetic core or through air), the multiple windings are magnetically connected through mutual inductances, and can be referred to as a transformer or coupled inductor. For multiple winding inductors / transf ormers, the windings exhibit both mutual inductance and self-inductance. A special form ofcoupled inductor is the three-phased reactor, which functionally is equivalent to three individual self-inductances, although the three windings are magnetically coupled. Such structure is often referred to as simply a reactor, although such structure involves mutual inductances, which is present in a transformer. Winding for such magnetic components may advantageously be of the type described above.

[0188] An example of a magnetic component which can be build from windings according to the present invention is a reactor or inductor which comprise a coil 13 around a ferromagnetic core 16 as illustrated in fig. 3. Such reactor or inductance is advantage to use e.g. as a filter.

[0189] Another example is if two coils 13 is provided around a ferromagnetic core 16 which then would be referred to as a transformer. A transformer is advantageous e.g. to electrically separate electric systems and change voltage levels.

[0190] Using a coil 13 as described above to provide components such as a reactor or transformer is advantageous in that the size of such components is reduce e.g. up to 1 / 3 or 1 / 2 of the size of such component build from traditional technology. This significantly reduced cost of material and foot print which is especially advantageous e.g. in large power generating plants such as wind turbines.

[0191] Two or more coils 13 may be connected in parallel or in series. This may be relevant if requirements to voltage or current requires a certain number of winding 1. Thus, it may be easier to manufacture e.g. three reactors each with 5 windings and connect these in series than to manufacture one with 15 just to mention one example. It may also turn out, that three series connected winding may be easier to cool than one reactor with three times the number of windings.

[0192] Fig. 4a illustrates an embodiment of the invention, where a cooling unit 18 of a cooling system is fluidly / thermic connected to the electric winding 1. More specific, the windings la-ln is in the form of a reactor 21 i.e. coiled around a core. The cooling system may comprise cooling unit 18, the cooling unit 18 may comprise a fan 20 and a heat exchanger 23 or both at the same time. The cooling unit 18 illustrated on fig. 4a comprises both a fan 20 and a heat exchanger 23.

[0193] The fan 20 is placed so as to provide a flow of air towards both the inner part 8, partly the outer part 9 and the core 16. By focusing on providing an airflow towards the inner part, focused cooling is provided towards the part of the winding that is generating the most heat.

[0194] As illustrated, insulating material 15 is positioned between the neighbouring windings to ensure no contact or arcs therebetween. This insulating material may have an additional function which is to distribute air flow from the fan 20 to the outer part 9 to thereby cool the plurality of windings / reactor 21. Alternatively or in addition, air guides (see fig. 4b) could be designed to optimize flow of air and at the same time also work as an insulating material for insulating two neighbouring windings. The air guides may be designed so as to guide air from the fan to predetermined parts of the reactor 21.

[0195] Cooling fluid should be understood as a gaseous or liquid fluid that may be circulated in the cooling system to transport heat away from the winding and / or core. If possible, liquid cooling fluid is preferred. A gaseous cooling fluid such as air may not need a cooling conduit to cool the winding and / or core. Flow of air may be facilitated by a fan towards the winding and / or core.

[0196] As illustrated in fig. 4a, the cooling unit 18 is provided to provide the highest flow of air at the center of the core / inner part of the coil. This is because it is this part of the coil that generates the most heat and thus where cooling most effectively is preventing this heat from spreading in the winding, core and / or to the ambient.

[0197] The flow of air from the fan 20 may be provided directly towards the inner part 8. From the inner part, the flow of air may be guided outwards towards and through airgaps 7 in the outer part 9. In this way the flow of air may cool both the inner and outer parts.

[0198] The flow of air may be guided e.g. from the design of the winding itself or from design of air guides / insolating material 15 towards the outer part 9.

[0199] As mentioned, the cooling unit 18 may comprise a heat exchanger 23. The heat exchanger may comprise a compartment where liquid or gaseous cooling fluid may exchange heat with the air flow provided from the fan. In this way a cold source is provided right before the fan i.e. between the fan and the winding to be cooled. More specific in right before the part of the winding that heats up the most and thereby an improved cooling is of the winding is facilitated.

[0200] It should be mentioned that the fan 20 may be mounted to the heat exchanger 23 and that the heat exchanger 23 comprise air guides that in addition to guide airflow from the fan also may be used to mount the cooling unit 18 to / on the coil.

[0201] It should be mentioned that if a second cooling unit is provided on a second side (not illustrated in fig. 4a) of the reactor 21 the cooling fluid may enter the heat exchanger 23 of the first side and exit the not illustrated heat exchanger on the second side of the reactor. Further, if the core and / or the winding comprises internal cooling channels they may also be connected in series with this flow of cooling fluid. With this said, it should be mentioned that each heat exchanger and internal cooling channel may have its own in and outlet.

[0202] Fig. 4b illustrates the reactor of fig. 4a with a cooling unit 18 on both sides in an exploded view (without a core). The two cooling units 18 may be designed to focus its cooling capacity i.e. flow of air on a specific part of the winding / core. This may be done e.g. by designing the air guides 24 to guide flow of air in a certain direction i.e. coordinated flow of air from the two fans 20 towards the winding / core.

[0203] The two cooling units may be mechanically connected and in this way mounted on or to the reactor 21.

[0204] The two cooling units may be part of the same closed cooling circuit or they may be supplied with individual cooling fluid i.e. two individual closed cooling circuits may exist. In fact, if the windings or core also comprise internal cooling channels additional closed cooing circuits may exist.

[0205] As illustrated both on fig. 4a and 4b, the reactor 21 may comprise feet’s via which it may be mounted to a support.

[0206] The principles of the cooling unit illustrated in fig. 4a and 4b in relation to a reactor 21 may also be used to cool a transformer or simply a busbar.

[0207] Fig. 5 illustrates method steps for machining an electrical winding according to an embodiment of the invention. The particular method relates to coupling two ends of an electrical winding, namely a first end and a second end with winding branches, but may be used for producing any kind of electrical windings of the present invention.

[0208] It should be mentioned that this may include printing both ends and the winding branches. Hence, the method may start by printing one end, then the transition to the windings, then the windings, then the transition to the second end and finally the second end.

[0209] Alternatively, the ends may be separate elements that is connected via an outer part. The outer part may be printed and during the manufacturing of the outer part it may be attached to the ends such as printed onto the ends. The outer part may be joints to the ends by means of welding, printing, soldering, etc.

[0210] It should be noted that the ends may comprise terminals for connecting the finalized electrical winding to other electric parts / conductors / windings of an electric system. Such terminals may be produced like the rest of the winding.

[0211] In a step SI of this particular method, the first end and outer part in the form of winding branches of a plurality of winding branches are monolithically united via individual transitions that may include rounded connections to shape concavely rounded interior comers between the first end and winding branches of the plurality of winding branches and to spatially separate winding branches of said plurality of winding branches.

[0212] The step of monolithically uniting the first end and winding branches may be implemented using various methods, for example methods, such as additivemanufacturing such as 3D printing, casting, and simply removing of material, via machining, from a bulk metal slab to form winding branches united with a first end.

[0213] In a step S2 of the method, the first end and the second end are electrically coupled and mechanically coupled via an outer part of the electrical winding formed by the plurality of winding branches.

[0214] An optional step may be applied i.e. a heat treatment to the finalized conductor / winding. A heat treatment may e.g. be 4 hours at 400C and upwards depending on the material. An advantage of heat treatment is that the particles of the manufactured conductor is mutual positioning or merging leading to higher conductivity both thermal and electrical. This is at least true for Aheadd® CPI 20 / 63 aluminium powders and other aluminium-iron-zirconium powder solutions. Such powders may be used in laser powder bed fusion machineries. Using this type of powder and heat treatment may lead to higher thermal stability, thermal conductivity, corrosion performance and surface finishing as well as higher electrical conductivity.

[0215] Outer part may in principles have any design / geometry providing flexibility thereto allowing the electrical winding to deform. It may be formed by winding branches being solid or have internal cavities to reduce the amount of material that is needed to manufacture the electrical winding. It may be formed by a web or as a hybrid between winding branches or web just to mention a few possible designs.

[0216] Internal cavities may be used as cooling channels and / or additional surface for conducting high frequency current. Accordingly, the ends and outer part may be designed for the particular panel / electric system in which it is used, for a particular type of current to conduct, for having a desired or dual functionality, etc.

[0217] One such functionality, beside the above-mentioned may be as a structural support. Hence, if needed the electrical winding may be designed to assist in carrying the weight of electric components connected thereto. Hence, its dimensions may be larger than what needed by it for carrying the required current. Similarly, its geometry may be designed of the combined purpose of mechanical support and electricconductance. This is especially true if such winding is flexible / deformable in that it may both assist in supporting and at the same time assist in absorbing vibrations.

[0218] It should be mentioned that the electrical winding 1 may be manufactured in two or more resolutions. The thicker layer the faster manufacturing. The layer thickness depends on the material and printing apparatus and may vary from a few millimetres to 20um, using some combinations the layer thickness is between 50um and 150um. In case of additive manufacturing resolution may be defined by thickness of the layers of which the electrical winding is build (another word for machined and processed). A first resolution that is finer i.e. having thinner layer size than a second resolution may be used when manufacturing the interface between the electrical winding and the part to which it is connected. Such interface may be the part of the terminal that is in contact with the other part. Alternatively, resolution may be determined by material deposition rate, material flow rate, etc. depending on the type of additive manufacturing used.

[0219] To avoid electric losses in connections between two electrical windings it is important that the two parts are having planer surfaces. The finer these interfaces are manufactured the better / the less post manufacturing processing is needed to ensure sufficient planer surfaces.

[0220] The second resolution manufactured e.g. with thicker layers would be more rough leading to more surface area. At least for middle and high frequency currents this may lead to conductance of more current without increasing the need for material / dimensions of the winding. In fact, the outer part may be manufactures intentionally with a corrugated surface to increase the current carrying outer surface of the electrical winding (current carrying with medium and high frequencies) because of more efficient cooling due to the turbulence of e.g. cooling air flow created due to the corrugated surface. It should be noted, that if the winding includes an interior space, the inner surface of the windings creating such interior space may also be corrugated for the same purpose. A corrugated surface has the effect, that it introduces turbulence in the flow of cooling fluid such as air. Increased speed of cooling fluid may lead to higher cooling effect.

[0221] As an example, the depth into the winding which is used for conducting current at medium and high frequencies may in a specific embodiment be approximate 1.5mm. In this specific example, the winding is made of copper with a resistivity of approximate 1.68pQ cm, a relative permeability of approximate 1 at a frequency of 2kHz. Thus, a winding for this particular embodiment may be hollow having winding thickness of 2 times 1.5mm. In practice such winding may be manufactured with a thickness 4-5mm leaving room for a cooling in the interior or simple reduction of winding material and thereby weight.

[0222] Knowing that skin effect also appears at e.g. 50Hz, a reference to a medium frequency with respect to skin effect is a reference to frequency starting around 500Hz where the design of the winding may account for the skin effect. The medium frequency range may be between 500Hz and 10kHz, above 10kHz may be referred to as high frequency where skin effect is a fact (the higher frequency, the closer to the surface the current will be conducted).

[0223] Further, it should be mentioned that the outer surface may also be corrugated or designed with fins for increasing heat dissipation from the electrical winding.

[0224] The electrical winding resulting from the method may be used as an electrical winding of an electrical installation. The electrical installation may be an electric panel which may be part of a renewable energy facility such as a wind turbine. Further, an electrical winding resulting from the method can be used inside an electric panel, i.e. in a cabinet / enclosure, or outside such panel, it can be used to connect separated panels, etc. Electric system on battery storage systems, in a vehicle, power to X systems, ships, etc. may also benefit from a winding according to the present invention.

[0225] A variant of an electrical winding according to the present invention is connected to a traditional cable or busbar. In such embodiment, a traditional busbar e.g. in the back of an electric panel or a traditional cable e.g. between two electric panels may be connected to an electrical winding of the invention. In this way a traditional cable or busbar may be connected to a component via a winding accordingto the invention. Thereby, an easy connection is facilitated due to the flexibility of the electrical winding of the invention.

[0226] However, note that manufacturing the electrical winding, and thus accomplishing the electrical and mechanical coupling between the first end and the second end, is typically performed prior to installing the electrical winding in the electrical installation, and prior to installing the electrical installation in the renewable energy facility. Thus, according to typical embodiments of the invention, the electrical and mechanical coupling is performed prior to installation / integration of the electrical winding. Nevertheless, methods according to the invention are not necessarily restricted to a particular sequence of steps. Further, various methods according to the invention may comprise additional steps, such as performing digital geometry optimization, additively manufacturing the electrical winding, and conducting current.

[0227] Summing up, a designer is designing a digital representation of the winding according to electrical, mechanical, structural, etc. requirements in e.g. a 3D CAD software such as Solidworks. Files (digital representation) from such 3D developing tool is exported to e.g. a 3D printer, where the winding is printed according to the CAD files.

[0228] The electrical winding is an embodiment of an electrical conductor, where the electrical winding comprises a first end 3 and a second end 4, the second end 4 being distal to the first end 3 and spaced apart from each other by an outer part. Each of these two ends may for example be galvanically coupled to respective terminals of an electrical installation. Typically, these terminals would be part of an electric panel i.e. inside an enclosure complying with requirements to high voltages i.e. voltages above 24V such as 110V, 230V, 400V, 690V just to mentions a few voltage levels of an electric installation in which the electrical winding of the present invention would be suitable. Mentioning these voltages, it should be mentioned, that in principle there are no lower limits as to the voltage and current i.e. such version of the electrical winding may be used in 24V or 48V systems conducting currents below 2A just to mention one example. Hence, the electrical winding of the present invention may be manufactures as a wire harness as an alternative to printed circuit board traces of an printed circuitboard or wire harness used for mounting in an electric panel. In terms of current, an electrical winding according to the present invention may conduct several hundreds of amps (16, 32, 64, and so on up to 100, 200 and so on up to e.g. 900A) up to a couple of thousand amps (1000A-3000A). Such electric installation may e.g. be in an energy facility, such that the electrical winding can facility transfer of current and / or voltage in such panel / energy facility. The energy facility may e.g. be a renewable energy facility.

[0229] In the embodiment illustrated in fig. 1, the first end and outer part and the second and outer part are monolithically united, since they are manufacturing from a single bulk piece of material, which was machined to provide the electrical winding 1. Here bulk piece of material should be understood as the material of which the electrical winding 1 is made.

[0230] The manufacturing of the electrical winding 1 may be done by an additive manufacturing process. Such manufacturing process may be based on, but not limited to, one of the following additive manufacturing processes: 3D printing, layer by layer printing, Wire Arc Additive Manufacturing, Fused Deposition Modeling, Direct Energy Deposition, Direct Metal Deposition, Sintering based processes, laser based processes, etc. It should be mentioned that the actual additive manufacturing process used to print or build the electrical winding may not be important as long as the material of which the electrical winding is build is an electrical conductive material.

[0231] It should be noted that even though the electrical windings la- In are illustrated as non-uniform windings, the design / geometry may take any machinable / printable shape. Such shape may be optimized according to conducting current (skin effect), cooling including air guidance, etc.

[0232] In an embodiment, a particular electrical winding la may have a non-uniform diameter (measured in a transversal direction) along the lengthwise direction, a well- defined winding diameter may nevertheless be determined at a transversal plane at which that winding has its smallest diameter.

[0233] Some figures further illustrate how a neighbor spacing of two neighboring winding branches may be quantified. As for the branch diameter / cross-sectional area, a non-uniform diameter / cross-sectional area of winding branches may result in a non- uniform distance between two winding branches. Nevertheless, a well-defined neighbor spacing (such as an airgap between two winding branches) may be determined by measuring in the transversal plane in which the largest spatial separation between two given winding branches is present.

[0234] Moreover, in an embodiment of the invention the perimeter length may vary in transversal planes at different positions in the lengthwise direction of the electrical winding. The perimeter length of a given segment may simply be measured as the sum of all lengths of perimeters of areas in a given transversal plane. Hence, the perimeter length of the second end 3 may thus be the length of the perimeter of a cross-section perpendicular to the longitudinal direction of the electrical winding.

[0235] The perimeter length of the outer part may be the sum of lengths of perimeters of all individual winding branches. As one winding branch may split from a stem to two or more twigs, the perimeter at one part of the outer part may be different from (twig part) another part (stem part). Hence, the sum of lengths of perimeters of the outer part may be the sum of all individual twigs or of all the individual stems. In case of multiple different possible perimeter lengths for the outer part, the smallest perimeter length may preferably be used in calculation of current conduction capability of the electrical winding.

[0236] In an embodiment, the electrical winding may comprise one or more cooling channels, where the cooling channel may be placed in the outer part inside one or more winding branches.

[0237] From the above it is now clear that the invention relates to an electrical winding designed with a first geometric shape at an inner part and with a second geometric shape at an outer part, wherein the first and second geometric shapes are different from each other. Thus, the electric winding of the present invention is non- uniform in its longitudinal direction i.e. in the direction following a current path froma first end of the electrical conductor to the second end of the electric winding. Hence, the current path could be said to include at least two different geometries i.e. when current is conducted from the first to the second end it is conducted through an electrical winding having at least two different geometries. Preferably, the two different geometries are monolithically united so that there is no physically connection between the two different geometries.

[0238] The invention has been exemplified above with the purpose of illustration rather than limitation with reference to specific examples of methods of producing the electrical winding and embodiments of the electrical winding. Details such as a specific method and system structures have been provided in order to understand embodiments of the invention. Note that detailed descriptions of well-known systems, devices, circuits, and methods have been omitted so as to not obscure the description of the invention with unnecessary details.List1. Electrical winding2. Cooling channel a. Inner cooling channel b. Outer cooling channel3. First end4. Second end5. Terminal connections a. First terminal connection b. Second terminal connection6. Intersection points7. Airgaps8. Inner part9. Outer part10. Inner cooling channel inlet11. Inner cooling channel outlet12. Current path12’. Individual current paths13. Coil14. Distance between two neighboring windings15. Insulating material16. Core a. First core part b. Second core part17. Cooling channel in core18. Cooling unit19. Air guide20. Fan21. Reactor22. Conductor branch23. Heat exchanger24. Air guide25. Cooling fluid inletCl cross-sectional area dl diameter / cross-sectional area of inner geometry / current path of inner geometry d2 diameter / width of outer geometry d2’ diameter / cross-sectional area of current path of outer geometry

Claims

Patent claims1. An electrical winding (1) configured to be coiled wherein said electrical winding (1) is characterized in that it has a non-uniform geometry.

2. An electrical winding according to any of the previous, wherein said electrical winding is of an electrically conductive material.

3. An electrical winding according to any of the previous, wherein said electrical winding is of a non-electrically conductive material, wherein said non-electrically conductive material is covered by an electrically conductive material.

4. An electrical winding according to any of the previous, wherein said electrical winding (1) is a liquid electrically conductive material provided in a shell.

5. An electrical winding according to any of the previous, wherein said shell is manufactured by an additive manufacturing process in a non-electrically conductive material.

6. An electrical winding according to any of the previous claims, wherein said electrical winding comprises a cooling channel (2).

7. An electrical winding according to any of the previous claims, wherein said electrical winding has a first (3) and a second (4) ends.

8. An electrical winding according to claim 7, wherein said first and second ends has terminal connections (5).

9. An electrical winding according to any of the previous, wherein an electrical component and said electrical winding (1) are monolithic.

10. An electrical winding according to any of the previous, wherein a cross-sectional area of said electrical winding (1) is between 0,1mm and 100mm, preferably between 0,2mm and 50mm, most preferably between 0,3mm and 10mm.

11. An electrical winding according to any of the previous, wherein said electrical winding (1) comprises a clips.

12. An electrical winding (1) according to any of the previous claims, wherein said electrical winding (1) comprises an inner part (8) and an outer part (9), wherein a diameter of said inner part (8) is smaller than the diameter of said outer part (9).

13. An electrical winding according to claim 12, wherein said inner part and said outer part are monolithic.

14. An electrical winding according to any of the previous claims, where said inner part (8) of the electrical winding is massive.

15. An electrical winding according to any of the previous claims, wherein said inner part (8) comprises an inner cooling channel (2a).

16. An electrical winding according to claim 15, wherein said inner cooling channel (2a) comprises an inner cooling channel inlet (10) and an inner cooling channel outlet (H).

17. An electrical winding according to any of the previous claims, wherein said outer part (9) of said electrical winding (1) comprises a geometry which is comprised by the list comprising: bionic, web, sponge and honeycomb.

18. An electrical winding according to any of the previous, wherein said electrical winding (1) comprises intersection points (6).

19. An electrical winding according to any of the previous, wherein said electrical winding (1) comprises airgaps (7)20. An electrical winding according to any of the previous, wherein at least one current path (2) branches off through said electrical winding (1).

21. An electrical winding according to any of the previous, wherein said geometry is configured to provide multiple current paths (12) through said electrical winding.

22. An electrical winding according to any of the preceding claims, wherein said electrical winding is a first electrical winding (la) which is connected in series to a second electrical winding wherein said second electrical winding (lb) is an electrical winding according to any of the preceding claims.

23. A first and second electrical windings (la, lb) according to claim 22, wherein said first electrical winding (la) comprises a first end (3) and said second electrical winging (lb) comprises a second end (4).

24. A first and second electrical windings (la, lb) according to claim 22-23, wherein said first electrical winding (la) comprises a first terminal connection (5a), said second electrical winding (lb) comprises a second terminal connection (5b) and wherein said first and second electrical windings (la, lb) are connected with one or more intermediate electric windings (1c, Id,..., In).

25. An electrical winding (1) according to any of the previous claims, wherein said electrical winding (1) is coiled around a core (16).

26. An electrical winding (1) according to claim 25, where said core (16) is made of air or a ferromagnetic material.

27. An electrical winding (1) according to claims 25-26, wherein said core is closed.

28. An electrical winding (1) according to claims 25-27, wherein said core (16) comprises two or more core parts (16a, 16b).

29. An electrical winding (1) according to any of the previous claims, wherein said core (16) comprises a cooling channel (17).

30. An electrical winding according to any of the previous, wherein said core is made of a ferrofluid provided in a shell.

31. An electrical winding according to any of the previous, wherein said shell is manufactured by an additive manufacturing process in a non-electrically conductive material.

32. An electrical winding (1) according to any of the previous claims, wherein said inner cooling channel (2a) is fluidly connected to a cooling unit (18).

33. An electrical winding (1) according to any of the previous claims, wherein said outer cooling channel (2b) is fluidly connected to a cooling unit (18).

34. An electrical winding (1) according to any of the previous claims, wherein said core (16) is fluidly connected to a cooling unit (18).

35. An electrical winding (1) according to any of the claims 32-34, wherein said cooling unit (18) is heat exchanger or fan.

36. An electrical winding (1) according to any of the claims 32-34, wherein said cooling unit (18) is a combination of heat exchanger and fan.

37. An electrical winding (1) according to any of the claims 32-36, wherein said cooling unit (18) generates a flow of air through said outer cooling channel (2b).

38. An electrical winding (1) according to claim 37, wherein said flow of air is guided by an air guide (19).

39. An electrical winding (1) according to any of the claims 37-38, wherein said air guide (19) is said insulation material (15)40. An electrical winding (1) according to any of the claims 32-40, wherein said cooling unit (18) is fluidly connected to said inner cooling channels (2a).

41. An electrical winding (1) according to any of the previous claims 32-40, wherein said cooling unit (18) is fluidly connected to said cooling channels (17) of said core (16)42. An electrical winding according to any of the preceding claims wherein said electrical winding is at least partly manufactured by additive manufacturing.

43. A transformer comprising a plurality of electrical windings (1) according to any of the preceding claims, wherein said plurality of electrical windings (1) are coiled around said core (16).

44. A reactor (21) comprising a plurality of electrical windings (1) according to any of the preceding claims, wherein said plurality of electrical windings (1) are coiled around said core (16).

45. A coil (13) comprising two or more electrical windings (la, ..., In) according to any of the preceding claims.

46. A coil (13) according to claim 45, wherein said two or more electrical windings (la, ..., In) are all identical.

47. A coil (13) according to claim 45, wherein said two or more electrical windings are non-identical.

48. A coil (13) according to claim 45, wherein two neighbouring electrical windings of said two or more electrical windings are spaced apart be a distance (14).

49. A coil (13) according to claim 48, wherein said distance (14) between two neighbouring electrical windings varies.

50. A coil (13) according to claim 48, wherein said distance (14) is below 25mm, preferably below 15mm, preferably below 10mm51. A coil (13) according to claim 48, wherein an insulation material (15) is placed between two or more neighbouring electrical windings.

52. A coil (13) according to claim 51, wherein said insulation material (15) is one selected from the list comprising: a sheet material, an applied material or a structure manufactured by additive manufacturing.

53. A core around which an electrical winding (1) according to any of the preceding claims are coiled, wherein said core (16) comprises a cooling channel (17).

54. A core according to claim 53, wherein said core (16) comprises a cooling channel inlet (17a) and a cooling channel outlet (17b).

55. A core according to claims 53-54, wherein said core (16) is at least partly manufactured by additive manufacturing 56. A method for connecting a first end (3) of a coil (13) comprising a plurality electrical windings (la-ln) to a second end (4) of said coil (13), the method comprising the steps of: monolithically uniting said first end (3) and a first electrical winding (la) of said plurality of electrical windings (la-ln) via an additive manufacturing process, monolithically uniting one or more additional electrical windings (1) to said first electrical winding (1) via said additive manufacturing process so as to establish said coil (13), and monolithically uniting said second end (4) and a second electrical winding (In) of said plurality of electrical windings (la-ln) via said additive manufacturing process.

57. A method for connecting a first end (3) of a coil (13) according to claim 56, wherein at least one of said plurality of electrical windings (la-ln) has a non-uniform geometry.

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