Reactor core, traction reactor, power device, and electric train set

Abstract

Disclosed is a reactor core (1) for a traction reactor (2) of a power plant (3), the reactor core (1) comprising: a first limb (10) and a second limb (12), both comprising a plurality of gaps (14); a first yoke (16) and a second yoke (18); and a plurality of connection joints (20) formed by a connection between the first yoke (16) and each of the first limb (10) and the second limb (12) and by a connection between the second yoke (18) and each of the first limb (10) and the second limb (12). The reactor core (1) further comprises an asymmetry with respect to the first central plane (A) achieved by an asymmetric arrangement of the plurality of gaps (14) with respect to the first central plane (A).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a reactor core for a traction reactor. In particular, the present disclosure relates to a reactor core and to a traction reactor comprising the reactor core. Further, the present disclosure relates to a power device comprising the traction reactor and to an electric train set comprising the power device. BACKGROUND

[0002] Today’s traction reactors are mechanical structures which are completely symmetric across three symmetry planes. When the core of the reactor is magnetically excited by currents running in a symmetric coil arrangement, a symmetric force distribution is gradually built up.

[0003] It has been shown by measurements and simulations that these two symmetric properties lead to a strong excitation of structural vibration modes which are particularly prone to generate high noise radiation, especially the triply symmetric mode around 2500 Hz. It is due to the vibration pattern of the acoustic class monopole mode of the reactor core (resulting from the symmetric mechanical structure and the symmetric force distribution) that this vibration mode exhibits a very high radiation efficiency.

[0004] As an example, traction reactors in operation in a train motor car are used to filter out PWM switching harmonics originating from the train’s converter. The reactor vibration and noise emission often leads to a poor sound environment in the passenger and train crew car. The current ripple originating from the train’s converter exhibits high amplitudes around 2 kHz and this mode is likely to be the cause of the noise and vibration problems encountered in such applications. SUMMARY

[0005] It is therefore an object of the present disclosure to provide an improved reactor core for a traction reactor. More particularly, it is an object of the present disclosure to provide a reactor core for a traction reactor, wherein the core is structurally asymmetric with respect to at least one central plane of the reactor core.

[0006] According to a first aspect of the present disclosure, the object is at least partially achieved by a reactor core according to claim 1.

[0007] Thus, a reactor core for a traction reactor of a power device is provided. The reactor core has an extension along a first axis, a second axis and a third axis. The first axis, the second axis and the third axis are orthogonal to each other. As seen along the second axis, the reactor core is divided into two halves at a first central plane extending along the first axis and extending along the third axis. As seen along the first axis, the reactor core is divided into two halves at a second central plane extending along the second axis and extending along the third axis.

[0008] The reactor core comprises a first limb and a second limb. The first limb and the second limb extend in parallel to a first axis, are symmetrically arranged about a first central plane, and comprise a plurality of gaps arranged transversely to the first axis. The gaps have individual thicknesses as seen along the first axis. The sum of the individual thicknesses of the plurality of gaps of the first limb and the second limb equals a predetermined nominal total thickness of all gaps.

[0009] The reactor core further comprises a first yoke and a second yoke. The first yoke and the second yoke extend in parallel to a second axis and are symmetrically arranged about a second central plane.

[0010] The reactor core further comprises a plurality of connection joints formed by connections between the first yoke and each of the first limb and the second limb and by connections between the second yoke and each of the first limb and the second limb.

[0011] The reactor core comprises an asymmetry about the first central plane caused by an asymmetrical arrangement of the plurality of gaps, and / or wherein a number of gaps comprised in the first limb differs from a number of gaps comprised in the second limb, and / or wherein the plurality of gaps comprises at least two different individual thicknesses, and wherein the sum of the individual thicknesses of the plurality of gaps of the first limb and the second limb remains equal to the total nominal thickness, and / or wherein each gap of the plurality of gaps of the first limb and the second limb comprises a material having a predetermined modulus of elasticity, which material respectively influences a first stiffness of the first limb and a second stiffness of the second limb as seen along the first axis, and wherein the first stiffness of the first limb and the second stiffness of the second limb are asymmetrically arranged about the first central plane.

[0012] The first yoke and / or the second yoke can comprise laminated steel, such as stacked laminated grain-oriented electrical steel.

[0013] A "gap" is also referred to as an air gap. An air gap is a non-magnetic part of the reactor core, and it is typically magnetically connected in series, which allows a substantial part of the magnetic flux to flow through the gap. The gaps comprised in the first limb and the second limb can be arranged perpendicular (or transversely) to the first axis. As an example, the nominal total thickness of the plurality of gaps in all limbs can be 54 mm.

[0014] Thus, a number of gaps comprised in the first limb can differ from a number of gaps comprised in the second limb. Individual thicknesses of gaps comprised in the first limb can differ from individual thicknesses of gaps comprised in the second limb.

[0015] Optionally, the reactor core further comprises an asymmetry about the first central plane and / or about the second central plane achieved by an asymmetrical arrangement of the plurality of joints about the first central plane and / or about the second central plane.

[0016] Optionally, the plurality of gaps of the first limb and the second limb are arranged asymmetrically about the first central plane and about the second central plane.

[0017] The asymmetry about the first central plane and / or about the second central plane is a structural asymmetry. The structural asymmetry is a result of the plurality of gaps and / or the connecting joints being arranged in a structurally asymmetric manner about the first central plane and / or about the second central plane. The asymmetry transforms the class-unipolar vibration mode of the traction reactor including the reactor core into a class-dipolar vibration mode which is less noise efficient, thereby reducing the noise emission from the traction reactor including the reactor core.

[0018] In order to maintain the electromagnetic properties and functionality of the traction reactor including the inventive reactor core, the total thickness of the plurality of gaps should be maintained equal to the nominal total thickness. Thereby, the reactor core can be made structurally asymmetric about the first central plane and / or about the second central plane without affecting the functionality of the traction reactor including the reactor core. Since the extension of the limbs is constant, changing the thickness of the gaps included in the limbs can affect the stiffness of the limbs. The stiffness of a limb having more gaps will be smaller than the stiffness of a limb having fewer gaps. Thus, the number of gaps and / or the thickness of the gaps can be changed to achieve different stiffness in different limbs.

[0019] The material of the gaps can affect the stiffness of the first limb and the second limb and thereby provide the reactor core with a structural asymmetry about the first central plane and / or about the second central plane.

[0020] Optionally, the plurality of gaps comprises at least a first type of gap and at least a second type of gap, the at least first type of gap comprising a first material having a first modulus of elasticity and the at least second type of gap comprising a second material having a second modulus of elasticity. The first type of gap and the second type of gap are arranged such that a first stiffness of the first limb and a second stiffness of the second limb are arranged asymmetrically about the first central plane and / or about the second central plane.

[0021] Thereby, by providing gaps having different materials, the stiffness of the first limb and the second limb can be changed to create a structural asymmetry of the reactor core without altering the number of gaps or the individual thickness of the gaps. Alternatively, the stiffness of the first limb and the second limb can be changed in combination with the different materials, individual thicknesses and / or numbers of gaps in the respective limb.

[0022] Optionally, the first material is talc and the second material is a glass fiber thermoset composite laminate, such as G11. Talc has a modulus of elasticity greater than 100 GPa and G11 has a modulus of elasticity less than 25 GPa.

[0023] Optionally, the plurality of connection joints comprises at least a first type of connection joint and at least a second type of connection joint. The at least first type of connection joint and the at least second type of connection joint are asymmetrically arranged with respect to the first central plane and / or with respect to the second central plane.

[0024] The first type of connection joint is structurally different compared to the second type of connection joint. The different connection joints affect the magnetic flux lines, resulting in a difference in magnetic forces at the different connection joints. Hence, a structural asymmetry of the reactor core can be provided by asymmetrically arranging the first type of connection joint and the second type of connection joint with respect to the first central plane and / or with respect to the second central plane. Optionally, the at least first type of connection joint comprises a butt joint, and the at least second type of connection joint comprises a step lap joint.

[0025] Optionally, the at least first type of connection joint comprises a butt joint, wherein the interfacing surface of the first yoke and / or the second yoke with the first limb and / or the second limb is parallel to the first central plane. The at least second type of connection joint comprises a butt joint, wherein the interfacing surface of the first yoke and / or the second yoke with the first limb and / or the second limb is parallel to the second central plane.

[0026] Optionally, the reactor core comprises laminated steel.

[0027] Optionally, the reactor core comprises laminated grain-oriented electrical steel.

[0028] According to a second aspect of the present disclosure, the object is at least partly solved by a traction reactor according to claim 10.

[0029] Hence, a traction reactor is provided, comprising a reactor core according to any one of the embodiments of the first aspect of the present disclosure, and wherein each of the first limb and the second limb comprises a winding.

[0030] Hence, compared to the traction reactors of the prior art, such traction reactors have less efficient noise radiation properties, such traction reactors have a structurally asymmetric reactor core with respect to the first central plane and / or with respect to the second central plane.

[0031] According to a third aspect of the present disclosure, the object is at least partly solved by a power device according to claim 11.

[0032] Hence, a power device is provided, comprising a traction reactor according to any one of the embodiments of the second aspect of the present disclosure. The power device further comprises at least one traction inverter and a transformer.

[0033] According to a fourth aspect of the present disclosure, the object is at least partly achieved by an electric train consist according to claim 12.

[0034] Thus, there is provided an electric train consist comprising at least one electric drive locomotive comprising a power device according to any one of the embodiments of the third aspect of the present disclosure.

[0035] Thereby, there is provided a locomotive providing an improved sound environment for passenger and train crew compartments.

[0036] As will be apparent to a person skilled in the art, the above aspects, the appended claims and / or examples described herein above and later below can be appropriately combined with each other.

[0037] Additional features and advantages are described in, and will be apparent from, the following Description, the and the Figures, and will be recognized by those skilled in the art (or can be learned by practice of the disclosure as set forth herein). BRIEF DESCRIPTION OF DRAWINGS

[0038] Further objects and advantages of the present disclosure as well as features of the present disclosure will be apparent from the description of one or more embodiments thereof, given below, with reference to the accompanying drawings, in which: Figure 1 A prior art traction reactor core is shown.

[0039] Figure 2 A class monopole vibration mode of a prior art traction reactor is shown.

[0040] Figure 3 A class dipole vibration mode of a traction reactor according to the second aspect of the present disclosure is shown.

[0041] Figure 4 A reactor core according to an example of the first aspect of the present disclosure is shown.

[0042] Figure 5 A reactor core according to an example of the first aspect of the present disclosure is shown.

[0043] Figure 6 A reactor core according to an example of the first aspect of the present disclosure is shown.

[0044] Figure 7 A reactor core according to an example of the first aspect of the present disclosure is shown.

[0045] Figure 8 A comparison of noise radiation between a prior art traction reactor and a traction reactor according to an example of the present disclosure is shown.

[0046] Figure 9 A traction reactor according to the second aspect of the disclosure is shown.

[0047] Figure 10 A power device according to the third aspect of the disclosure and an electric train set according to the fourth aspect of the disclosure are shown. DETAILED DESCRIPTION

[0048] The present disclosure is explained in greater detail below with reference to the examples shown in the drawings. The present disclosure should not be considered limited to the described examples of embodiments. Like numbers refer to like elements throughout the description.

[0049] The terminology used herein is for the purpose of describing particular aspects of the disclosure only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. All terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs unless otherwise defined.

[0050] As with any other industrial product, power devices such as transformers, reactors, etc. must comply with various requirements on noise levels. It is known to the skilled person that the acoustic power emitted from a vibrating structure subjected to a force distribution can be expressed as:

[0051] wherein denotes a set of modal shapes associated with the mechanical properties of the structure, and the operator depends implicitly on the geometry of the structure, on the frequency, and also on the material properties of the acoustic and structural medium under discussion. Furthermore, denotes the Hermitian transpose of a vector, and denotes the regular vector transpose. The quantity will be explained here as the scalar or dot product of two vectors, which indicates that the resulting acoustic power goes to zero when these two vectors are orthogonal. It is proposed in the present disclosure to bring about the orthogonality by promoting asymmetric winding resonance modes subjected to a force distribution that is inherently symmetric.

[0052] As an example of a power device generating high noise levels, Figure 1 ​​A prior art reactor core 1' for a prior art traction reactor is shown. The prior art reactor core 1' has an extension along a first axis z, a second axis x and a third axis y (not shown), the first axis z, the second axis (x) and the third axis y being orthogonal to each other. As seen along the second axis x, the prior art reactor core 1' is divided into two halves at a first central plane A extending along the first axis z and along the third axis y. As seen along the first axis z, the prior art reactor core 1' is also divided into two halves at a second central plane B extending along the second axis x and along the third axis y.

[0053] The prior art reactor core 1' comprises a first limb 10 and a second limb 12. The first limb 10 and the second limb 12 extend in parallel to the first axis z and are symmetrically arranged about the first central plane A. The first limb 10 and the second limb 12 comprise a plurality of gaps 14' arranged transversely to the first axis z. As seen along the first axis z, the gaps 14' have an individual thickness t. The sum of the individual thicknesses t of the plurality of gaps 14' of the first limb 10 and the second limb 12 is equal to a predetermined nominal total thickness T.

[0054] The prior art reactor core 1' further comprises a first yoke 16 and a second yoke 18. The first yoke 16 and the second yoke 18 extend in parallel to the second axis x and are symmetrically arranged about the second central plane B.

[0055] The prior art reactor core 1' also comprises a plurality of connection joints 20' formed by a connection between the first yoke 16 and each of the first limb 10 and the second limb 12 and by a connection between the second yoke 18 and each of the first limb 10 and the second limb 12. The connection joints 20' and the gaps 14' are all symmetrically arranged about the first central plane A and / or the second central plane B.

[0056] As discussed in the background section, the prior art traction reactor is a mechanical structure which is completely symmetric across three symmetry planes. Figure 1 The planes A and B are shown in the middle. When the core of the reactor is magnetically excited by the current running in the symmetrical coil arrangement, a symmetrical force distribution is gradually formed, which leads to a vibration of the structure that significantly contributes to the high noise radiation.

[0057] It has been shown by measurements and simulations that these two symmetrical properties (symmetrical structure and symmetrical force distribution) lead to a strong excitation of structural vibration modes that are particularly prone to generate high noise radiation, especially the triply symmetric modes around 2500 Hz.

[0058] The present disclosure aims to break the structural symmetry of the reactor core by introducing structural asymmetry with respect to the first central plane A and / or with respect to the second central plane B. The structural asymmetry is achieved by arranging the plurality of gaps (air gaps) and / or the connecting joints (or the properties of the gaps and connecting joints) asymmetrically with respect to the first central plane A and / or with respect to the second central plane B.

[0059] The variation in gap properties can bring about a beneficial asymmetric modal shape, while mixing the butt joints and the step lap joints can also result in distorting the symmetric electric force distribution, plus also affecting the mechanical resonance properties.

[0060] The asymmetric vibration will also convert the acoustically efficient monopole-like mode into a much less efficient dipole-like mode, as combined in Figure 2 and Figure 3 It will be explained that these figures show the symmetric and asymmetric vibration modes, respectively, and further explain their acoustic properties.

[0061] Figure 2 The symmetric mode acting on the first yoke 16 of the prior art traction reactor 2’ of the prior art reactor core 1’ is shown conceptually. For clarity of the drawing, only the forces acting on the first yoke 16 are shown. However, similar forces / movements can be observed on the first limb 10, the second limb 12, and on the second yoke 18. It can be seen that as the first yoke 16 vibrates, a certain volume of surrounding medium AV (positive or negative) is displaced. This displacement radiates noise into the audible far field, which can be perceived as disturbing noise.

[0062] In contrast, Figure 3 The asymmetric vibration mode shown in Figs. 1 and 2, which is achieved by the reactor core 1 and the traction reactor 2 according to the present disclosure, causes one part of the first yoke 16 to move upwards as the other part moves downwards, thereby theoretically resulting in a net volume displacement AV equal to zero. Such an asymmetric vibration mode radiates noise into the near field, which is not audible at a distance. In other words, it is not perceived as disturbing noise. Figure 2 and Figure 3 The central plane A is shown in Figs. 1 and 2. Figure 2 The arrows M in Figs. 1 and 2 illustrate how each part of the first yoke 16 of the prior art traction reactor 2’ (located on opposite sides of the central plane A) is simultaneously displaced in the same direction to achieve displacement in a direction parallel to the central plane A. In Figs. 3 and 4, which illustrate the traction reactor 2 according to the present disclosure, Figure 3 In Figs. 3 and 4, the asymmetric vibration mode results in opposite directions M, -M on opposite sides of the central plane A. Similar to Figure 2 Likewise, Figure 3Only forces acting on the first yoke 16 are shown. However, similar forces / movements can be observed on the first limb 10, the second limb 12 and on the second yoke 18 as well.

[0063] Due to the design of the reactor core 1 in which the windings are arranged on the limbs 10, 12, it is particularly efficient to break the structural asymmetry about the central plane A, since in operation of e.g. a traction reactor large symmetrical forces are generated along the limbs 10, 12 towards and away from the yokes 16, 18. The most efficient way to break the structural asymmetry about the central plane A is an asymmetric arrangement of the gaps about the first central plane A.

[0064] Figures 4 to 7 An example embodiment of a reactor core 1 for a traction reactor 2 according to the present disclosure is illustrated. In the illustrated example, the reactor core 1 has an extension along a first axis z, a second axis x and a third axis y (not shown), the first axis z, the second axis (x) and the third axis y being orthogonal to each other. As seen along the second axis x, the reactor core 1 is divided into two halves at a first central plane A extending along the first axis z and along the third axis y. As seen along the first axis z, the reactor core 1 is also divided into two halves at a second central plane B extending along the second axis x and along the third axis y.

[0065] The reactor core 1 comprises a first limb 10 and a second limb 12. The first limb 10 and the second limb 12 extend in parallel to the first axis z and are symmetrically arranged about the first central plane A. The first limb 10 and the second limb 12 comprise a plurality of gaps 14 arranged transversely to the first axis z. As seen along the first axis z, the gaps 14 have an individual thickness t. The sum of the individual thicknesses t of the plurality of gaps 14 of the first limb 10 and the second limb 12 equals a predetermined nominal total thickness T.

[0066] The reactor core 1 further comprises a first yoke 16 and a second yoke 18. The first yoke 16 and the second yoke 18 extend in parallel to the second axis x and are symmetrically arranged about the second central plane B.

[0067] The first yoke 16 and / or the second yoke 18 can comprise laminated steel, such as stacked laminated grain-oriented electrical steel.

[0068] The reactor core 1 further comprises a plurality of connection joints 20 formed by a connection between the first yoke 16 and each of the first limb 10 and the second limb 12 and by a connection between the second yoke 18 and each of the first limb 10 and the second limb 12.

[0069] By the asymmetric arrangement of the plurality of gaps 14 and / or by the asymmetric arrangement of the plurality of connection joints 20 (both about the first central plane A and / or about the second central plane B),Figures 4 to 7 The example reactor core 1 shown in the figure comprises an asymmetry with respect to the first central plane A and / or with respect to the second central plane B.

[0070] The reactor core is made of ferromagnetic material and comprises “gaps” 14. The gaps 14 are also referred to as air gaps 14. The air gaps 14 are non-magnetic portions of the reactor core 1 and are typically magnetically connected in series, which allows a considerable portion of the magnetic flux to flow through the gaps 14. The gaps 14 comprised in the first limb 10 and the second limb 12 can be arranged perpendicular (or transverse) to the first axis z. As an example, the nominal total thickness of the plurality of gaps 14 in all limbs 10, 12 can be 54 mm.

[0071] The asymmetry with respect to the first central plane A and / or with respect to the second central plane B is a structural asymmetry. The structural asymmetry is a result of the plurality of gaps 14 and / or the connecting joints 20 being arranged in a structurally asymmetric manner with respect to the first central plane A and / or with respect to the second central plane B. Such a structural asymmetry can be achieved by selecting an asymmetric positioning / position of the gaps 14 and / or the connecting joints 20 and / or by selecting properties of individual gaps 14 and / or connecting joints 20 such that the structural symmetry or symmetric force distribution is broken. The asymmetry transforms the class-unipolar vibration mode of the traction reactor 2 in positive operation of the reactor core 1 into a class-dipolar vibration mode which is less noisy, thereby reducing the noise emission from the traction reactor 2 comprising the reactor core 1.

[0072] The plurality of gaps 14 of the first limb 10 and the second limb 12 can be asymmetrically arranged with respect to the first central plane A and / or with respect to the second central plane B. Thus, the number of gaps 14 comprised in the first limb 10 can be different from the number of gaps 14 comprised in the second limb 12. The individual thickness t of the gaps 14 comprised in the first limb 10 can be different from the individual thickness t of the gaps 14 comprised in the second limb 12. In the present disclosure, the nominal total thickness is exemplified by 54 mm, i.e. the total thickness of all gaps 14 comprised in the reactor core 1. In the present disclosure, the nominal total thickness is exemplified by 54 mm, i.e. the total thickness of all gaps 14 comprised in the reactor core 1. Figure 1 In the prior art reactor core 1’ shown in the figure, the gaps 14 are symmetrically positioned with respect to the first central plane A. In the prior art, the gaps 14’ at the interface between the limbs and the yoke can be 1,5 mm, wherein two interface gaps 14’ are symmetrically placed on each side of the first central plane A. The remaining gaps 14’ can be 8 mm, wherein three gaps 14’ are symmetrically located on each side of the central plane A, resulting in a total thickness of 54 mm.

[0073] According to the present disclosure, the plurality of gaps 14 can comprise at least two different individual thicknesses t, and the sum of the individual thicknesses t of the plurality of gaps 14 of the first limb 10 and the second limb 12 remains equal to the total nominal thickness T. As an example, the plurality of gaps 14 of the first limb 10 and the second limb 12 can comprise a first gap 14 with a first individual thickness t1 and a second gap 14 with a second individual thickness t2, wherein the first individual thickness t1 is different from the second individual thickness t2.Figure 4 As exemplified in the above, the total thickness of the plurality of gaps 14 should remain equal to the nominal total thickness T. Thereby, the reactor core 1 can be made structurally asymmetric with respect to the first central plane A and / or with respect to the second central plane B, without affecting the electromagnetic properties of the traction reactor 2 comprising the reactor core 1.

[0074] As mentioned above, the total thickness of the plurality of gaps 14 should remain equal to the nominal total thickness T. Thereby, the reactor core 1 can be made structurally asymmetric with respect to the first central plane A and / or with respect to the second central plane B, without affecting the electromagnetic properties of the traction reactor 2 comprising the reactor core 1.

[0075] In the example of Fig. 1, the arrangement is asymmetric, since five gaps 14 are arranged along the first limb 10 on one side of the central plane A, the five gaps comprising two interface gaps of t3= 1,5 mm and three gaps of t1= 8 mm. On the other side of the central plane A, the second limb 12 is arranged with three gaps 14 of t2= 9 mm. Thereby, the reactor core 1 is structurally asymmetric with respect to the first central plane A, and the total thickness of the plurality of gaps 14 remains equal to the total nominal thickness T of 54 mm. Figure 4 In the example of Fig. 1, the arrangement is asymmetric, since five gaps 14 are arranged along the first limb 10 on one side of the central plane A, the five gaps comprising two interface gaps of t3= 1,5 mm and three gaps of t1= 8 mm. On the other side of the central plane A, the second limb 12 is arranged with three gaps 14 of t2= 9 mm. Thereby, the reactor core 1 is structurally asymmetric with respect to the first central plane A, and the total thickness of the plurality of gaps 14 remains equal to the total nominal thickness T of 54 mm.

[0076] Figure 5 In the example of Fig. 1, the arrangement is asymmetric, since five gaps 14 are arranged along the first limb 10 on one side of the central plane A, the five gaps comprising two interface gaps of t3= 1,5 mm and three gaps of t1= 8 mm. On the other side of the central plane A, the second limb 12 is arranged with three gaps 14 of t2= 9 mm. Thereby, the reactor core 1 is structurally asymmetric with respect to the first central plane A, and the total thickness of the plurality of gaps 14 remains equal to the total nominal thickness T of 54 mm.

[0077] The plurality of gaps 14 can comprise at least a first type of gap 14’ and at least a second type of gap 14”, the at least first type of gap comprising a first material having a first modulus of elasticity and the at least second type of gap comprising a second material having a second modulus of elasticity. The first type of gap 14’ and the second type of gap 14” are arranged such that the first stiffness of the first limb 10 and the second stiffness of the second limb 12 are asymmetrically arranged with respect to the first central plane A and / or with respect to the second central plane B.

[0078] Thus, the material of the gaps 14 can influence the stiffness of the first limb 10 and the second limb 12 and thereby provide the reactor core 1 with structural asymmetry with respect to the first central plane A and / or with respect to the second central plane B. In the example of Fig. 1, the reactor core 1 comprises a first limb 10 and a second limb 12, the first limb 10 and the second limb 12 being arranged on opposite sides of a first central plane A and / or on opposite sides of a second central plane B. Figure 5 Figure 1 ​​The prior art reactor core 1' of Figure 1 is provided with similar gaps 14. However, the first limb 10 of this example comprises three gaps 14' of a first type and two gaps 14" of a second type, while the second limb 12 comprises five gaps 14" of the second type, thereby causing a structural asymmetry with respect to the first central plane A.

[0079] Thereby, by providing gaps 14 of different materials, the stiffness of the first limb 10 and the second limb 12 can be varied to create a structural asymmetry of the reactor core 1 without altering the number of gaps 14 or the individual thickness t of the gaps 14. Alternatively, the stiffness of the first limb 10 and the second limb 12 can be varied by a combination of different materials, individual thicknesses t and / or numbers of gaps 14 in the respective first limb 10 and second limb 12.

[0080] As an example, the first material can be talc, and the second material can be a glass fiber thermoset composite laminate, such as G11. Talc has an elastic modulus of more than 100 GPa, and G11 has an elastic modulus of less than 25 GPa.

[0081] The plurality of connecting joints 20 can comprise at least a first type of connecting joint 20' and at least a second type of connecting joint 20". The at least first type of connecting joint and the at least second type of connecting joint can be asymmetrically arranged with respect to the first central plane A and / or with respect to the second central plane B, as shown in Figure 4 , Figure 6 and Figure 7 .

[0082] The first type of connecting joint 20' is structurally different compared to the second type of connecting joint 20". The different connecting joints 20 enable different stiffnesses and differences in magnetic flux lines passing through the connecting joints. The differences in magnetic flux lines can result in differences in magnetic forces acting on the reactor core 1. Thereby, a structural asymmetry of the reactor core 1 can be provided by asymmetrically arranging the first type of connecting joint 20' and the second type of connecting joint 20" with respect to the first central plane A and / or with respect to the second central plane B.

[0083] The at least first type of connecting joint 20' can comprise a butt joint, and the at least second type of connecting joint 20" can comprise a stepped lap joint.

[0084] As Figure 4The second type of connection joint 20" of the second limb 12 interfacing with the first yoke 16 and the second yoke 18, as exemplified in the middle, comprises a stepped lap joint, which, when arranged asymmetrically with respect to the first central plane A, can cause an asymmetric force distribution in the reactor core 1, as shown. The stepped lap joint of the present disclosure comprises interfaces between the limb and the yoke, which are parallel to the third axis y (not shown) and extend along the first axis z and along the second axis x. In comparison to the butt joint, the stepped lap joint creates different magnetic flux lines, resulting in a difference in the magnetic forces acting on the reactor core 1. In Figure 4 In the example of the middle, the structural asymmetry is achieved by arranging two stepped lap joints 20" at the interfaces between the second limb 12 and the first yoke 16 and the second yoke 18 on one side of the first central plane A, while two butt joints (connection joints 20' of the first type) are arranged on the other side of the central plane A.

[0085] Alternatively, the at least first type of connection joint 20' can comprise a butt joint, wherein the interfacing surfaces of the first yoke 16 and / or the second yoke 18 with the first limb 10 and / or the second limb 12 are parallel to the first central plane A. The at least second type of connection joint 20" can also comprise a butt joint, wherein the interfacing surfaces of the first yoke 16 and / or the second yoke 18 with the first limb 10 and / or the second limb 12 are parallel to the second central plane B. As Figure 6 and Figure 7 As exemplified in the middle and the right, such first type of connection joint 21' and second type of connection joint 21" can be arranged asymmetrically with respect to the first central plane A and / or with respect to the second central plane B to achieve the intended structural asymmetry of the reactor core 1.

[0086] Figure 8 The impact of the example traction reactor 2 of the present disclosure on noise radiation is illustrated in comparison to the prior art traction reactor 2'. The vertical axis shows the noise radiation W expressed in dB. The first curve 100 shows the noise radiation of the prior art traction reactor 2'. The second curve 200 shows an example of asymmetrically arranged butt joints and talc gap material. The third curve 300 shows an example of asymmetrically arranged stepped lap joints and talc material. The fourth curve 400 shows an example of one limb and asymmetrically arranged talc material in the butt joint. It can be seen that there is a significant reduction in noise radiation around 2500 Hz, i.e. at a frequency at which conventional traction reactors typically tend to produce high noise radiation. In other words, the traction reactor 2 according to the present disclosure provides a significantly improved acoustic environment for the crew and passengers of a train set comprising the traction reactor 2.

[0087] Figure 9A traction reactor 2 according to the second aspect of the present disclosure is shown, which comprises a reactor core 1 of any one of the example embodiments of the first aspect of the present disclosure. Each of the first limb 10 and the second limb 12 comprises a winding 22. Such traction reactor 2 thus has less efficient noise radiation properties compared to the prior art traction reactor 2', such traction reactor having a structurally asymmetric reactor core 1 with respect to the first central plane A and / or with respect to the second central plane B.

[0088] Figure 10 A power device 3 according to the third aspect of the present disclosure is illustrated. The power device 3 comprises a traction reactor 2 according to any one of the embodiments for the second aspect of the present disclosure. The power device further comprises at least one traction converter 24 and a transformer 26.

[0089] Figure 10 A motor train consist 4 according to the fourth aspect of the present disclosure is further shown. The motor train consist comprises at least one electric drive locomotive 28, which comprises a power device 3 according to any one of the embodiments of the third aspect of the present disclosure. In this example, two electric drive locomotives 28 are shown.

[0090] The traction reactor 2 is located between the traction converter 24 and the transformer 26. The traction converter is fed with DC, which is converted to 50 Hz mains electricity. However, due to the pulse width modulation technique (PWM), the traction converter 24 also generates harmonics. Such harmonics need to be filtered out before reaching the transformer 26. The traction reactor 2 is applied to filter out the harmonics and to send the 50 Hz signal to the transformer 26.

Claims

1. A reactor core (1) for a traction reactor (2) of an electric power unit (3), the reactor core (1) having extensions along a first axis (z), a second axis (x), and a third axis (y), the first axis (z), the second axis (x), and the third axis (y) being orthogonal to each other, as seen along the second axis (x), the reactor core (1) being divided into two halves at a first central plane (A) extending along the first axis (z) and along the third axis (y), as seen along the first axis (z), the reactor core (1) being divided into two halves at a second central plane (B) extending along the second axis (x) and along the third axis (y), the reactor core (1) comprising: - A first limb (10) and a second limb (12), wherein the first limb (10) and the second limb (12) extend parallel to the first axis (z), are arranged symmetrically about the first central plane (A), and include a plurality of gaps (14) arranged transversely to the first axis (z), as seen along the first axis (z), the gaps (14) having individual thicknesses (t), and wherein the sum of the individual thicknesses (t) of the plurality of gaps (14) of the first limb (10) and the second limb (12) is equal to a predetermined nominal total thickness (T). - A first yoke (16) and a second yoke (18), wherein the first yoke (16) and the second yoke (18) extend parallel to the second axis (x) and are arranged symmetrically about the second central plane (B). - A plurality of connecting joints (20), which are formed by the connection between the first yoke (16) and each of the first limb (10) and the second limb (12) and by the connection between the second yoke (18) and each of the first limb (10) and the second limb (12), and The reactor core (1) includes an asymmetry about the first central plane (A) achieved by the asymmetric arrangement of the plurality of gaps (14), and / or wherein the number of gaps included in the first limb is different from the number of gaps included in the second limb, and / or wherein the plurality of gaps (14) includes at least two different individual thicknesses (t), and wherein the sum of the individual thicknesses (t) of the plurality of gaps (14) of the first limb (10) and the second limb (12) remains equal to the total nominal thickness (T), and / or wherein each of the plurality of gaps (14) of the first limb (10) and the second limb (12) includes a material having a predetermined elastic modulus, as seen along the first axis (z), the material affecting the first stiffness of the first limb (10) and the second stiffness of the second limb (12), and wherein the first stiffness of the first limb (10) and the second stiffness of the second limb (12) are arranged asymmetrically about the first central plane (A).

2. The reactor core according to claim 1, further comprising the asymmetry about the first central plane (A) and / or about the second central plane (B) achieved by the asymmetric arrangement of the plurality of connectors (20) about the first central plane (A) and / or about the second central plane (B).

3. The reactor core (1) according to claim 1 or 2, wherein, The plurality of gaps (14) of the first limb (10) and the second limb (12) are arranged asymmetrically with respect to the first central plane (A) and with respect to the second central plane (B).

4. The reactor core (1) according to claim 1, wherein, The plurality of gaps (14) include at least a first type of gap (14') and at least a second type of gap (14''), the at least first type of gap comprising a first material having a first elastic modulus and the at least second type of gap comprising a second material having a second elastic modulus, wherein the first type of gap (14') and the second type of gap (14'') are arranged such that the first stiffness of the first limb (10) and the second stiffness of the second limb (12) are arranged asymmetrically about the first central plane (A) and / or about the second central plane (B).

5. The reactor core (1) according to claim 4, wherein, The first material is talc, and the second material is a glass fiber thermosetting composite laminate, such as G11.

6. The reactor core (1) according to any one of the preceding claims, wherein, The plurality of connectors (20) include at least a first type of connector (20') and at least a second type of connector (20''), wherein the at least first type of connector (20') and the at least second type of connector (20'') are arranged asymmetrically about the first central plane (A) and / or about the second central plane (B).

7. The reactor core (1) according to claim 6, wherein, The at least first type of connection joint (20') includes a butt joint, and the at least second type of connection joint (20'') includes a stepped lap joint.

8. The reactor core (1) according to claim 6, wherein, The at least first type of connector (20') includes a butt joint, wherein the interface connecting surfaces of the first yoke (16) and / or the second yoke (18) with the first limb (10) and / or the second limb (12) are parallel to the first central plane (A), and wherein the at least second type of connector (20'') includes a butt joint, wherein the interface connecting surfaces of the first yoke (16) and / or the second yoke (18) with the first limb (10) and / or the second limb (12) are parallel to the second central plane (B).

9. A traction reactor (2) comprising a reactor core (1) according to any one of claims 1 to 8, wherein, Each of the first limb (10) and the second limb (12) includes a winding (22).

10. An electric power unit (3) comprising a traction reactor (2) according to claim 9, and further comprising at least one traction converter (24) and a transformer (26).

11. An electric trainset (4) comprising at least one electric locomotive (28), the at least one electric locomotive comprising the power unit (3) according to claim 10.

Images