Electrical choke

Abstract

An electrical device 1 comprises: a magnetic core (10, Figure 5) and an electrical conductor assembly 11 forming at least one winding W around a section of the magnetic core and comprising a plurality of components mounted and electrically connected to one another, the at least one winding being formed by at least two of the components. The electrical device may be an electrical choke, and may be configured as a common-mode choke. The components of the electrical conductor assembly preferably comprise at least one conductor plate (110A, 110B, Figure 5) and / or one or more conductor bars (111A, 111B, Figure 5). At least one conductor plate may be part of a printed circuit board (PCB). An electrical converter may comprise the electrical device, which may also form part of an electrical propulsion unit or an aircraft. A method of manufacturing an electrical device, comprising mounting and electrically connecting at least two components of an electrical conductor assembly to one another so as to form at least one winding, is also provided.

Description

FIELD The present disclosure particularly relates to an electrical device, to an electrical converter, to an electrical propulsion unit, to an aircraft and to a method for manufacturing an electrical device. BACKGROUND Electrical propulsion units for aircrafts allow the use of sustainably generated energy and can be particularly quiet. In addition, electrical propulsion units often only require little maintenance compared to, e.g., combustion engines. An important aspect is the supply and distribution of electrical power. In the case of electrically driven aircrafts, e.g., converters may be used, e.g., to convert a direct current (DC) from a battery or the like to an alternating current (AC) to drive an electric motor. In this and other applications, electrical devices such as chokes can be used to block higher-frequency ACs while passing DC and lower-frequency ACs in a circuit. In electric propulsion units, the currents supplied to the electric motor may be relatively high, so that electrical conductors of corresponding electrical chokes can have a relatively large thickness. Therefore, manufacturing electrical chokes for electrical propulsion units can be complex. There is a need to provide an electrical device that addresses at some of the aforementioned problems or at least provides a useful alternative to known electrical devices. SUMMARY According to an aspect, an electrical device (e.g., for an electrical converter and / or another electrical device) is provided, the electrical device comprising a magnetic core and an electrical conductor assembly. The electrical conductor assembly forms at least one winding around a section of the magnetic core and comprises a plurality of electrically conducting components mounted and electrically connected to one another. Therein, the at least one winding is formed by at least two of the components. This is based on the idea to partition the conductor into a plurality of components that do not have to be bent for creating the windings of, e.g., a coil around the magnetic core. Although counter-intuitive, because a plurality of parts is used instead of e.g., a one-piece coil, this allows a simplified manufacturing with a high precision. As a result, this further allows a to reduce the overall weight and size of the electrical device. The electrical device may be an electrical choke or an inductor. The components of the electrical conductor assembly may comprise at least one conductor plate and / or at least one conductor bar. The at least one conductor bar may be mounted and electrically connected to the at least one conductor plate. Therein, the at least one winding may be (at least partially) formed by the at least one conductor plate (one or more conductor plates) and / or the at least one conductor bar (one or more conductor bars). Such plate-shaped conductor plates and bar-shaped conductor bars can be manufactured particularly simple and reliably, even with large cross sections allowing correspondingly large electrical currents. In an example, the at least one conductor plate has two parallel (and opposing) planar surfaces. One of the planar surfaces may be in surface contact with the at least one conductor bar. This allows a simple manufacturing and reliable electric connection. The electrical device may comprise a printed circuit board, PCB. The at least one conductor plate may be a part of the PCB. By this, other electrical components can easily be connected. Further, production and mounting of the electrical device can be simplified. For example, the electrical conductor assembly comprises a plurality of conductor plates and a plurality of conductor bars. This allows to create multiple windings in a simple manner. At least some of the conductor plates may be arranged coplanar to one another. By this, a simplified design can be achieved. For example, two or more of the conductor plates of the electrical conductor assembly are part of the PCB. By this, an arrangement of conductor plates can be manufactured in a simple manner. In some embodiments, the PCB is a first PCB, and the electrical device further comprises a second PCB. Therein, one, two or more of the conductor plates of the electrical conductor assembly may be part of the second PCB. That is, the electrical device may comprise two PCBs, each having one or more conductor plates that each form at least a part of a winding around the magnetic core. This allows to further simplify the manufacturing process. For example, the first PCB and the second PCB are spaced apart from one another and / or oriented parallel to one another. This allows to simply design windings using conductor plates of the PCBs. The magnetic core and / or the conductor bars may be arranged between the first PCB and the second PCB. Like this, the parts can be assembled quickly and reliably. At least some of the conductor bars may be arranged parallel to one another. This allows a simple configuration. The magnetic core may be arranged between conductor bars. In some embodiments, the electrical conductor assembly forms a plurality of windings around a respective section of the magnetic core. Specifically, the conductor plates and the conductor bars may form the plurality of windings. This allows an effective reduction of noise. In an example, the magnetic core has an oval or toroidal shape. Such a shape allows to easily arrange a plurality of windings around sections of the magnetic core. At least one of the conductor bars may be arranged inside the magnetic core and / or at least one of the conductor bars may be arranged outside of the magnetic core. By this an effective coil can be created. The electrical conductor assembly may comprise two separate conducting paths (e.g., electrically separated from one another), each of which being wound around (sections of) the magnetic core. Therein, the electrical device may be configured as a common-mode choke. Common-mode chokes can limit common-mode currents with reduced ground currents, improve compliance to emission limits, reduce machine-bearing currents and / or reduce switching losses (decoupling the winding / cable capacitances from the switch node). According to an aspect, an electrical converter, e.g., for an electrical propulsion unit, is provided, comprising an electric machine and the electrical device (e.g., choke) of any aspect or embodiment described herein. The electrical converter may comprise an input, an output and / or power electronics. The power electronics may be configured to receive electrical power via the input and / or to provide electrical power via the output. The at least one electrical device may be electrically connected to the power electronics. The electrical converter may be configured to convert a direct current, DC, electrical power received at the input into an alternating current, AC, electrical power provided at the output. Therein, the at least one electrical device may be electrically connected between the input of the power electronics, or between the power electronics and the output. For example, the electrical device of the electrical converter is configured as a common-mode choke. By this, optimized filtering properties are possible for the respective application. According to an aspect, an electrical propulsion unit for an aircraft is provided, comprising an electric machine and the electrical converter of any aspect or embodiment described herein. According to an aspect, an aircraft is provided comprising the electrical converter of any aspect or embodiment described herein and / or comprising the electrical propulsion unit according to any aspect or embodiment described herein. According to an aspect, a method of manufacturing an electrical converter is provided, the method comprising: providing a magnetic core; arranging at least two components of an electrical conductor assembly (e.g., at least one conductor plate and at least one conductor bar) at the magnetic core; and mounting and electrically connecting the at least two components of the electrical conductor assembly to one another so as to form at least one winding around a section of the magnetic core. The skilled person will appreciate that except where mutually exclusive, a feature or parameter described in relation to any one of the above aspects may be applied to any other aspect. Furthermore, except where mutually exclusive, any feature or parameter described herein may be applied to any aspect and / or combined with any other feature or parameter described herein. BRIEF DESCRIPTION OF THE DRAWINGS Exemplary embodiments are now described with reference to the figures, wherein: FIG. 1 shows an aircraft in the form of an airplane with electric propulsion units; FIG. 2 shows a block diagram of an electric machine, a battery and an electrical converter; FIG. 3 shows an electrical choke of the electrical converter of FIG. 2; FIG. 4 shows components of the electrical choke of FIG. 3; FIG. 5 shows an exploded view of the electrical choke of FIG. 3; FIGS. 6 and 7 show components of the electrical choke of FIG. 3 forming coil windings; FIG. 8 shows an electrical diagram including several electrical chokes in accordance with FIG. 3; FIG. 9 shows components for the electrical choke of FIG. 3; FIG. 10 shows an arrangement with several electrical chokes in accordance with FIG. 3; FIG. 11 shows components for the electrical choke in accordance with FIG. 9; FIG. 12 shows the components of FIG. 11 mounted on a printed circuit board; FIGS. 13 and 14 show components for the electrical choke of FIG. 3; and FIG. 15 shows a method of manufacturing an electrical choke. The following table lists the reference numerals used in the drawings with the features to which they refer: Ref no. Feature Figure 1 Electrical device (electrical choke) 23 10 2 Aircraft 1 3 Electrical converter 2 10 Magnetic core 59 10 12 13 14 11 Electrical conductor assembly 34 12 (first) printed circuit board (PCB) 3 10 12 13 (second) printed circuit board (PCB) 3 10 20 Fuselage 1 21 Wings 1 22 Electric propulsion unit 1 23 Battery 2 Ref no. Feature Figure 30 Housing 2 31 Input 28 32 Output 2 33 Power electronics 2 34 Motor drive controller 2 35 Heat sink 2 100 Through hole 5 110A, 110B Conductor plate 45679 10 111A-111E Conductor bar 345679 10 12 13 14 112 Planar surface 5 113A, 113B Conducting path 4 114 Outer part 6 115 Inner part 6 116 Skewed part 6 117 Connecting section 56 118 Hole 56 220 Electric machine 2 221 Propeller 1 330A-330C Inverter phase unit 2 331 Electrical component 2 350 Fin 2 4A-4E Electrical conductor 2 A1-A4 Arm 11 13 14 M Isolator material 3 P Path of the electric current 6 S1-S3 Step 15 W Winding 346789 DETAILED DESCRIPTION FIG. 1 shows an aircraft 2 in the form of an airplane having a fuselage 20, wings 21 5 and one or more, in this example two electric propulsion units 22. The electric propulsion units 22 each comprise a respective propeller 221. Each of the propellers 221 comprises a plurality of rotor blades, in this example two rotor blades. In alternative embodiments, the aircraft 2 comprises, for example, one or more fans instead of propellers 221 and / or a plurality of propellers, fans, or the like (with more or less rotor blades). 10 The respective propeller 221 is driven by an electric machine 220 of the corresponding electric propulsion unit 22, see FIG. 2. FIG. 2 shows an electrical converter 3 of one of the electric propulsion units 22 in the form of an inverter. The electrical converter 3 is electrically connected with a battery 23 if the aircraft 2. The electrical converter 3 receives electrical energy from the battery 23. In the present example, the battery 23 is mounted in the aircraft 2, e.g., on a central body of the aircraft 2. The electrical converter 3 may be (alternatively or in addition) configured to provide electrical energy to the battery 23. To receive electrical energy from the battery 23, the electrical converter 3 comprises an input 31. The input 31 comprises two electrical conductors 4D, 4E. The input 31 is a direct current, DC, input. Further, the electrical converter 3 comprises an output 32. Via the output 32, the electrical converter 3 is electrically connected to the electric machine 220. Here, the electric machine 220 is an electric motor. The electric machine 220 can be a three-phase (e.g., synchronous) machine. Therefore, the output 32 comprises three electrical conductors 4A, 4B, 4C. The output 32 is a three-phase alternating current, AC, output. That is, the electrical converter 3 receives DC from the battery 23, converts it into a three-phase AC and provides the three-phase AC to the electric machine 220. The electric machine 220 may comprise multiple winding sets each with, e.g., three phases. To provide three (or one or more) phases, the electrical converter 3 comprises power electronics 33 with three inverter phase units 330A, 330B, 330C (or one or more inverter phase units), one for each of the phases. Each of the inverter phase units 330A, 330B, 330C comprises a plurality of electrical components 331. Here, each of the inverter phase units 330A, 330B, 330C comprises a plurality of electrical components in the form of switches, particularly semiconductor switches such as transistors or the like. The inverter phase units 330A, 330B, 330C and their electrical components 331 are arranged and mounted in a housing 30 of the electrical converter 3. The housing 30 encloses the power electronics 33. The electrical converter 3 further comprises a motor drive controller 34. The motor drive controller 34 controls the inverter phase units 330A-330C. Here, the motor drive controller 34 provides PWM (pulse width modulation) signals to the inverter phase units 330A-330C. A heat sink 35 is mounted on the housing 30 to remove heat from the housing 30 produced by the electrical components 331 inside the housing 30. The heat sink 35 comprises fins 350. In an alternative embodiment, no heat sink is mounted on the housing 30. The battery 23 is mounted on the aircraft 2, in this example in the fuselage 20. The electric motor 220 and the electrical converter 3 are a part of one of the electric propulsion units 22 of the aircraft 2. The electric propulsion units 22 of the aircraft 2 have the same construction. Further, the electrical converter 3 comprises at least one electrical device in the form of an electrical choke 1. In the present example, the electrical converter 3 comprises a plurality of electrical chokes 1 as described in the following. FIG. 3 shows one of the electrical chokes 1 of the electrical converter 3 of FIG. 2. The electrical choke 1 comprises a magnetic core 10 and an electrical conductor assembly 11. The magnetic core 10 is surrounded by outer conductor bars 111A of the electrical conductor assembly 11, so it is not visible in FIG. 3 showing the mounted state of the electrical choke 1, but it is visible, e.g., in FIG. 5. The electrical conductor assembly 11 forms at least one winding W around a section of the magnetic core 10. The magnetic core 10 has the shape of a hollow cylinder (more specifically, of an oval or circular cylinder). The magnetic core 10 defines a through hole 100. Alternatively, the magnetic core 10 could have a toroidal shape or any kind of a ring shape. The electrical conductor assembly 11 forms a plurality of windings W. Each winding W is wound around a section of the hollow cylinder. That is, each winding W extends from one front surface of the magnetic core 10, through the through hole 100 along the inside of the magnetic core 10, around the opposite front surface of the magnetic core 10 and along the outside of the magnetic core 10 back to the first front surface of the magnetic core 10. The electrical conductor assembly 11 comprises a plurality of components mounted and electrically connected to one another. Specifically, the at least one winding W is formed by at least two of the components. In the example of FIGS. 3 to 5, the plurality of windings W is formed by a plurality of components of the electrical conductor assembly 11. That is, the windings W are not formed by a wire which is bent around the magnetic core 10. Instead, a plurality of separate parts is mounted to one another without being bent. The magnetic core 10 can also be referred to as core. The magnetic core 10 is an iron core. E.g., the magnetic core 10 comprises a magnetic material. The magnetic material has a relative permeability of, e.g., pr» 1, e.g., of more than 1000 or more than 10000. The magnetic material may be a ferromagnetic or ferrimagnetic material. Here, the magnetic core 10 comprises iron. The magnetic material may, e.g., comprise or consist of steel, iron, Metglas, mu-metal or a nanocrystalline iron-based alloy. The magnetic material may be an iron-based alloy with a crystalline structure. The alloy may comprise Fe, Cu, Nb, Si and B. The electrical choke 1 comprises a first printed circuit board, first PCB 12, and a second PCB 13. The PCBs 12, 13 are arranged parallel to one another and spaced apart from one another. Between the PCBs 12, 13, the magnetic core 10 is arranged. As can be seen particularly in FIG. 4, the components of the electrical conductor assembly 11 comprise a plurality of conductor plates 110A, 110B and a plurality of conductor bars 111A, 111B. Each of the conductor plates 110A, 110B is mounted and electrically connected to at least one of the conductor bars 111 A, 111B. As shown in FIG. 4, the electrical conductor assembly 11 comprises a ring of inner conductor bars 111B and a ring of outer conductor bars 111 A. The ring of inner conductor bars 111B is arranged in the ring of outer conductor bars 111A. As can be seen in FIG. 5, the magnetic core 10 is arranged between the ring of outer conductor bars 111A and the ring of inner conductor bars 111B. The magnetic core 10 is arranged within the ring of outer conductor bars 111 A. The ring of inner conductor bars 111B is arranged within the magnetic core 10. The outer conductor bars 111A have the same shape among each other. The inner conductor bars 111B have the same shape among each other. In this example, the conductor bars 111 A, 111B consist of copper. Alternatively, they comprise, or consist of, copper and / or other materials. The conductor bars 111 A, 111B are electric conductors. The conductor bars 111A, 111B are arranged parallel to one another. The magnetic core 10 defines a cylinder axis. The conductor bars 111A, 111B are oriented parallel to the cylinder axis. Each of the conductor plates 110A, 110B has two parallel planar surfaces 112. One of the planar surfaces 112 is in surface contact with one or two of the conductor bars 111 A, 111B. The planar surfaces 112 are oriented perpendicular to the cylinder axis. A first group of conductor plates 110A, 110B are arranged coplanar to one another within the same first plane, a second group of conductor plates 110A, 110B are arranged coplanar to one another within the same second plane. The magnetic core 10 and the conductor bars 111 A, 111B are arranged between the first and second planes. The conductor plates 110A, 110B in the first plane form a part of the first PCB 12. The conductor plates 110A, 110B in the second plane form a part of the second PCB 13. That is, the conductor plates 110A, 110B are embedded in an isolator material M. In FIGS. 4 to 7 the isolator material M is not shown so that the conductor plates 110A, 110B can be seen. FIG. 3 shows the PCBs 12, 13 with the isolator material M. The conductor plates 110A, 110B are electrically isolated from the other conductor plates 110A, 110B of the respective PCB 12, 13 by the isolator material M. The conductor bars 111 A, 111B are spacers. In this example, the conductor plates 110A, 110B consist of copper. Alternatively, they comprise, or consist of, copper and / or other materials. The conductor plates 110A, 110B are electric conductors. Here, the conductor plates 110A, 110B are formed by multi-layer PCB copper traces. The electrical conductor assembly 11 forms the plurality of windings W around the respective sections of the magnetic core 10, wherein the conductor plates 110A, 110B and conductor bars 111 A, 111B form the plurality of windings W. FIG. 6 shows some of the conductor plates 110A, 110B and conductor bars 111 A, 111B of the electrical conductor assembly 11. Each of the windings W is formed by two conductor plates 110A, 110B and two conductor bars 111A, 111B. FIG. 7 shows two conductor plates 110A and two conductor bars 111A, 111B forming one winding W. The winding W is formed by an outer conductor bar 111 A, an inner conductor bar 111B, a conductor plate 110A of the first PCB 12 and a conductor plate 110A of the second PCB 13. The windings W form a helix around the magnetic core 10. As illustrated in FIG. 6, the path of the electric current P extends, in this order (or reverse order, depending on the direction of the current) through the outer conductor bar 111 A, through the conductor plate 110A of the second PCB 13, through the inner conductor bar 111B and through the conductor plate 110A of the first PCB 12. The conductor plates 110A connecting two conductor bars 111 A, 111B with one another are skewed. The surface of each conductor plate 110A that is in contact with an inner conductor bar 111B is arranged at an angular offset around the cylinder axis with respect to the surface of this conductor plate 110A that is in contact with the respective outer conductor bar 111 A. On the other hand, the conductor bars 111 A, 111B are straight (along the cylinder axis). The conductor plates 110A connecting two conductor bars 111 A, 111B with one another have an outer part 114 and an inner part 115. The outer part 114 is arranged further away from the cylinder axis than the inner part 115. The inner and outer parts 114, 115 are offset around the cylinder axis relative to one another. The inner and outer parts 114, 115 are connected with one another by a skewed part 116. The inner and outer parts 114, 115, and the skewed part 116, are formed in one piece. Alternatively, or in addition, the (inner and / or outer) conductor bars 111 A, 111B could be skewed. Then, the conductor plates 110A could formed radially straight. The conductor plates 110B that are only mounted to one (outer) conductor bar 111A, serve for the electrical connection of the electrical choke 1 to other parts of the electrical converter 3. As can be seen, e.g., in FIG. 6, the conductor bars 111A, 111B have holes 118. Here, as an example, each conductor bar 111A, 111B has two holes 118 on either side in contact with a respective conductor plate 110A, 11 OB. The conductor plates 110A, 11 OB have connecting sections 117 aligned with the holes 118 of the respective conductor bar 111A, 111B. The connecting sections 117 may comprise a screw each, a welding point, a pin and / or a solder point. The connecting sections 117 the multiple layers of copper PCB traces of the respective PCB 12, 13. As can be seen, e.g., in FIG. 4, the electrical conductor assembly 11 comprises two separate conducting paths 113A, 113B wound around the magnetic core 10. Therefore, the electrical choke 1 comprises four connectors (conductor plates 110B) for connection of other parts of the electrical converter 3. For example, one electrical choke 1 filters the input current at the input 31. The positive terminal of the input 31 is connected to one connector of one conducting path 113A of the electrical choke 1. The other connector of this conducting path 113A is connected to a positive terminal of the power electronics 33. The negative terminal of the input 31 is connected to one connector of the other conducting path 113B of the electrical choke 1. The other connector of this conducting path 113B is connected to a negative terminal of the power electronics 33. Turning now to FIG. 8, and with reference to FIG. 3, (e.g., surface-mounted) capacitors and / or resistors can be integrated on the first and second PCBs 12, 13. This allows to realize a coupled multi-stage filter with a single magnetic core 10. This allows to further increase the core utilization. The capacitors C shown in FIG. 8 may be surface-mounted on one or both of the PCBs 12, 13. In FIG. 8, each winding section corresponds to one winding W as shown in FIG. 7. As such, the conducting paths 113A, 113B are connected via capacitors C (two capacitors C in series with a connection ground therebetween). In this example, this is provided between each of two windings W, but other arrangements are also conceivable, e.g., with just one such capacitor C (or, as shown in FIG. 8, two in series). Further, the conductor bars 111 A, 111B can have a design optimized for the high-frequency behaviour of the target choke or inductor. The solid conductor bars 111A, 111Bcan have a profiled surface pattern. This allows to tune the impedance at different frequencies. In an alternative embodiment, at least one of the conductor plates 110A on PCB 12 and / or 13 can be replaced by copper bar or the like, e.g. in the same shape, thereby removing at least one of PCB 12, 13. FIG. 9 shows a design for an electrical choke such as the electrical choke 1 of FIG. 3, but with only one PCB 12. Here, instead of the conductor plates 110A, 110B of the second PCB 13, each one inner and one outer conductor bar 111 A, 111B are formed in one piece via a cross-bar. Thus, the corresponding choke comprises U-shaped conductor bars 111C. The conductor bars (e.g., copper bars) to form a multi-turn choke or inductor may or may not be identical. As be seen, e.g., in FIGS. 11 and 12, when one of the conductor plates embedded in a PCB is replaced with a conductor bar 111C, a whole skewed conductor bar is formed winding around the magnetic core. The electrical conductor assembly 11 under this design comprises the skewed conductor bar 111C and the conductor plate 110A on the single PCB 12. Therein, the conductor bar 111A extends over three sides of the magnetic core 10 (here: one end face, the inner side and the outer side). The fourth side (the second end face) is formed by the conductor plate 110A. Specifically, the conductor bar 111C comprises a first arm A1 extending on the outer side of the magnetic core 10, a second arm A2, extending on the one end face of the magnetic core 10, and a third arm A3 extending on the inner side of the magnetic core 10. Therein the second arm A2 connects the first arm A1 with the third arm A3. The conductor bar 111C is made in one piece. This allows to simply place the conductor bar 111C on the core 10 and then mechanically contact and electrically connect the conductor plate 110A, thereby forming a winding around the magnetic core 10. The conductor bar 111C is U-shaped. The conductor bar 111C extends over % of the sides of the magnetic core 10. The conductor plate 110A extends over % of the sides of the magnetic core 10. FIG. 12 shows the mounted state on the PCB 12, wherein two separate coils are formed on the magnetic core 10, each including a plurality of (here three) windings around the magnetic core 10. Here, for the example of a choke, the two coils are mirror symmetrical to one another (about a vertical plane). Alternatively, an inductor can be provided by forming all windings as circular duplicates. In another embodiment, all conductor bars (e.g., copper bars) can be used to form the helical winding structure without involving PCB copper layers. This is shown in FIG. 13 and FIG. 14 for one winding (FIG. 13) and three windings (FIG. 14). Conductor bar 111D and conductor bar 111E can be joined mechanically by means of, for example but not exclusively, screws. Although in the example shown in the Figures, conductor bar 111D and conductor bar 111E each covers % of the sides (here: two sides) of the magnetic core 10 (e.g., toroid core), other partitioning arrangements are also possible. To form a multiple turn choke or inductor, the involved copper parts may or may not be circularly identical. According to FIGS. 13 and 14, the conductor bars 111D, 111Ehave an L-shaped cross section. The outer conductor bars 111D have first and second arms A1, A2, the inner conductor bars 111E have further two arms A3, A4. The four arms A1-A4 extend ober each of the four sides of the magnetic core 10 (inner, outer sides and two opposing end sides). In the electrical converter 3, the electrical choke 1 is operated as a common-mode choke. One or more further electrical chokes 1 can be connected between the AC side of the power electronics 33 and the output 32. The electrical chokes 1 serve as EMI filters to suppress the current noise caused by high-speed switching processes. As such, the common-mode chokes carry the full-scale current through the converter. Around the conductor bars 111A, 111B, indirect cooling can be implemented to allow high current densities in the copper path. The required common mode inductance can be realized by selecting a proper core size. The conductor bars 111A, 111B and the conductor plate 110A, 110B thickness are sized based on the current rating. The current capacity can also be easily scaled by paralleling the electrical choke 1 unit and constructing an electrical choke array, e.g., on a single PCB, making the design capable for high-power applications. Such an arrangement is shown in FIG. 10. Therein the first and second PCBs 12, 13 extend over a plurality of electrical chokes 1. According to FIG. 3, the PCBs 12, 13 are formed circular, but it is possible that one or both of the PCBs 12, 13 extend further, e.g., as shown in FIG. 10. Alternatively, or in addition, further electrical components may be mounted on one or both of the PCBs 12, 13, such as one or more of the inverter phase units 330A-330C. As illustrated in FIG. 2, an electrical choke 1 forms a PCB on which an inverter phase unknit 330A-330C is assembled. That is, the electrical choke 1 is integrated into a larger PCB. This avoids a usage of high current connecting structures, which could be heavy and bulky. FIG. 15 illustrates a method of manufacturing an electrical choke 1, such as the electrical choke of FIG. 3. The method comprises the following steps: Step S1: Providing a magnetic core 10. Step S2: Arranging at least two components of an electrical conductor assembly 11 at the magnetic core 10. Step S3: Mounting and electrically connecting the at least two components of the electrical conductor assembly 11 to one another so as to form at least one winding W around a section of the magnetic core 10. For manufacturing an electrical converter, the electrical choke 1 is electrically connected to power electronics 33 thereof and, e.g., to an input 31 and / or an output 32 thereof. Conventional common-mode chokes impede a compact design of power converters due to the following reasons: In a conventional winding-based design scheme, multi-turn chokes are challenging to wind as large-size wires are required to carry the main current. On the other hand, a single-turn-based choke design results in low-utilizing of the magnetic core and a larger inductor size. The present examples provide a PCB-based choke design with a single magnetic core and multiple winding turns. The windings W comprise sections, e.g., in the form of multi-layer PCB copper traces and sections in the form of solid copper bars, which are mechanically joined to form the helical winding pattern around the magnetic core 10. By doing so, the solid copper conductor bars 111 A, 111B geometries can be customized to maximize the filling percentage of the window area in the magnetic core 10 to allow high current flows. The PCB base of the inductor can also be readily integrated into a larger PCB which for example can comprise a power electronic converter (e.g., one or more of the inverter phase units 330A-330C). The structure also allows tight dimensional tolerance control over the solid bars and PCB traces, which helps to minimize the magnetic asymmetries among the winding turns. Notably, the described structure can also be used to construct filter inductors or energystoring inductors. Further, on the PCBs 12, 13 and where the conductor bar 111 A, 111B and PCB 12, 13 copper regions are joined, an impedance matching circuit can be connected. This allows to avoid voltage reflections. It will be understood that the invention is not limited to the embodiments abovedescribed and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.

Claims

1. An electrical device (1) comprising:a magnetic core (10); andan electrical conductor assembly (11) forming at least one winding (W) around a section of the magnetic core (10) and comprising a plurality of components mounted and electrically connected to one another, wherein the at least one winding (W) is formed by at least two of the components.

2. The electrical device (1) of claim 1, wherein the electrical device (1) is an electrical choke.

3. The electrical device (1) of claim 1 or 2, wherein the components of the electrical conductor assembly (11) comprise at least one conductor plate (110A, 110B) and / or one or more conductor bars (111A-111C) mounted and electrically connected one another, wherein the at least one winding (W) is at least partially formed by the at least one conductor plate (110A, 110B) and / or the one or more conductor bars (111A-111C).

4. The electrical device (1) of claim 3, wherein the at least one conductor plate (110A, 110B)has two parallel planar surfaces (112), one of which being in surface contact with the at least one conductor bar (111A-111C).

5. The electrical device (1) of claim 3 or 4, further comprising a printed circuit board, PCB (12), wherein the at least one conductor plate (110A, 110B) is a part of the PCB (12).

6. The electrical device (1) of any one of claims 3 to 5, wherein the electrical conductor assembly (11) comprises a plurality of conductor plates (110A, 110B) and a plurality of conductor bars (111A-111C).

7. The electrical device (1) of claim 6, wherein at least some of the conductor plates (110A, 110B) are arranged coplanar to one another.

8. The electrical device (1) of claim 6 or 7, wherein at least some of the conductor plates (110A, 110B) are part of the PCB (12).

9. The electrical device (1) of claim 8, wherein the PCB (12) is a first PCB (12), the electrical device (1) further comprising a second PCB (13), wherein some of the conductor plates (110A, 110B) are part of the second PCB (13).

10. The electrical device (1) of claim 9, wherein the first PCB (12) and the second PCB (13) are spaced apart from one another and oriented parallel to one another.

11. The electrical device (1) of claim 9 or 10, wherein the magnetic core (10) and / or the conductor bars (111A-111C) are arranged between the first PCB (12) and the second PCB (13).

12. The electrical device (1) of any one of claims 6 to 11, wherein at least some of the conductor bars (111 A-111C) are arranged parallel to one another.

13. The electrical device (1) of any one of claims 6 to 12, wherein the electrical conductor assembly (11) forms a plurality of windings (W) around a respective section of the magnetic core (10), wherein the conductor plates (110A, 110B) and conductor bars (111A-111C) form the plurality of windings (W).

14. The electrical device (1) of any preceding claim, wherein the magnetic core (10) has a cylindrical or toroidal shape.

15. The electrical device (1) of any one of claims 6 to 14, wherein at least one of the conductor bars (111A-111C) is arranged inside the magnetic core (10) and at least one of the conductor bars (111 A-111C) is arranged outside of the magnetic core (10).

16. The electrical device (1) of any preceding claim, wherein the electrical conductor assembly (11) comprises two separate conducting paths (113A, 113B) wound around the magnetic core (10), wherein the electrical device (1) is configured as a commonmode choke.

17. An electrical converter (3) comprising an input (31), an output (32) and power electronics (33), wherein the power electronics (33) is configured to receive electrical power via the input (31) and to provide electrical power via the output (32), and at least one electrical device (1) of any preceding claim is electrically connected to the power electronics (33).

18. The electrical converter (3) of claim 17, configured to convert a DC electrical power received at the input (31) into an AC electrical power provided at the output (32), wherein the at least one electrical choke (1) is electrically connected between the input (31) the power electronics (33) or between the power electronics (33) and the output (32).

19. The electrical converter (3) of claim 17 or 18, wherein the electrical device (1) is configured as a common-mode choke.

20. An electrical propulsion unit (22) for an aircraft (2), the electrical propulsion unit 5 comprising an electric machine (220) and the electrical converter (3) of any one of claims 17 to 19.

21. An aircraft (2) including the electrical converter (3) of any one of claims 17 to 19 and / or the electrical propulsion unit (22) of claim 20.1022. A method of manufacturing an electrical device (1), comprising the steps of:providing (S1) a magnetic core (10);arranging (S2) at least two components of an electrical conductor assembly (11) at the magnetic core (10); and15 mounting and electrically connecting (S3) the at least two components of theelectrical conductor assembly (11) to one another so as to form at least one winding (W) around a section of the magnetic core (10).

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