TRANSFORMER STRUCTURE, AND LOCOMOTIVE TRACTION TRANSFORMER

Abstract

 The present disclosure provides a transformer structure and a traction transformer for a locomotive and relates to the technical field of transformers. The transformer structure comprises: a core and a coil; the core comprises side yokes and a core limb, and the coil is sleeved outside the core limb. Since a transformer having a transformer structure needs to be placed in an oil tank, when the sum of the cross-sectional areas of the side yokes on any two sides of the core limb is greater than or equal to the cross-sectional area of the core limb, the transformer can be designed with different schemes according to different locomotives, the shape and area of the transformer structure can be adjusted for spatial limitations of different locomotives, and the cross-sectional areas of different side yokes are set by using the cross-sectional area of the core limb as a reference, so that it is easier to match a suitable oil tank, it can be better adapted to a vehicle body structure with great spatial limitation, and the technical problem can be effectively alleviated that the space for the transformer structure in the prior art is greatly limited so that the transformer cannot be placed, and therefore the transformer structure of the present disclosure is more suitable for popularization and use.

Description

Technical Field

[0001] The present disclosure relates to the technical field of transformers, and in particular to a transformer structure and a traction transformer for a locomotive.

Background Art

[0002] The traction transformer is an important component of a traction system of a rail transit locomotive, which is used for converting the 25kV high voltage obtained on an overhead line system into a voltage suitable for being supplied for operation of a traction motor and other motors and electrical appliances.

[0003] In the prior art transformer, two core limbs are required, therefore the space for the transformer is greatly limited in some vehicle models, and the transformer cannot be placed using this scheme; and a high frequency signal of a traction winding in the transformer will have a certain effect on an auxiliary winding, resulting in poor electromagnetic compatibility.

Summary

[0004] An object of the present disclosure is to provide a transformer structure, which can at least effectively alleviate one of the technical problems that the space for the transformer structure in the prior art is greatly limited and the transformer cannot be placed.

[0005] Another object of the present disclosure is to provide a traction transformer for a locomotive, which comprises the transformer structure described above and which has all the characteristics of the transformer structure.

[0006] Embodiments of the present disclosure are implemented as follows:

An embodiment of the present disclosure provides a transformer structure, comprising: a core and a coil,

wherein the core comprises side yokes and a core limb, the side yokes form an accommodating region configured to close a magnetic circuit, the core limb is disposed in the accommodating region, and the coil is sleeved outside the core limb so that the coil is located in the accommodating region; and

a sum of cross-sectional areas of the side yokes of any two sides of the core limb is greater than or equal to a cross-sectional area of the core limb.

[0007] In an optional embodiment of the present disclosure, the side yokes comprise a first side yoke, a second side yoke, a third side yoke, and a fourth side yoke;
the first side yoke, the second side yoke, the third side yoke, and the fourth side yoke are sequentially connected in an end-to-end manner, and any two adjacent ones of the first side yoke, the second side yoke, the third side yoke, and the fourth side yoke are disposed perpendicular to each other, such that the accommodating region defined by the first side yoke, the second side yoke, the third side yoke, and the fourth side yoke is in a rectangular shape.

[0008] In an optional embodiment of the present disclosure, the core limb has a circular cross-sectional shape, and each of the first side yoke, the second side yoke, the third side yoke, and the fourth side yoke has a rectangular cross-sectional shape.

[0009] In an optional embodiment of the present disclosure, a cross-sectional area of the first side yoke is not equal to a cross-sectional area of the third side yoke.

[0010] In an optional embodiment of the present disclosure, a cross-sectional area of the second side yoke is not equal to a cross-sectional area of the fourth side yoke.

[0011] In an optional embodiment of the present disclosure, a sum of the cross-sectional area of the first side yoke and the cross-sectional area of the third side yoke is greater than or equal to the cross-sectional area of the core limb.

[0012] In an optional embodiment of the present disclosure, a sum of the cross-sectional area of the second side yoke and the cross-sectional area of the fourth side yoke is greater than or equal to the cross-sectional area of the core limb.

[0013] In an optional embodiment of the present disclosure, the cross-sectional area of the first side yoke or the third side yoke is greater than or equal to a quarter of the cross-sectional area of the core limb.

[0014] In an optional embodiment of the present disclosure, the cross-sectional area of the second side yoke or the fourth side yoke is greater than or equal to a quarter of the cross-sectional area of the core limb.

[0015] In an optional embodiment of the present disclosure, an outer corner at a position where any two of the first side yoke, the second side yoke, the third side yoke, and the fourth side yoke are connected is provided as a chamfer.

[0016] In an optional embodiment of the present disclosure, the first side yoke is detachably connected to the second side yoke and the fourth side yoke.

[0017] In an optional embodiment of the present disclosure, the coil comprises a traction winding layer, a high-voltage winding layer, and an auxiliary winding layer; and
the auxiliary winding layer is sleeved over the high-voltage winding layer, and in turn the high-voltage winding layer is sleeved over the traction winding layer, with the auxiliary winding layer is located at the outermost layer.

[0018] In an optional embodiment of the present disclosure, a thickness of the auxiliary winding layer is less than a thickness of the traction winding layer; and/or the thickness of the auxiliary winding layer is less than a thickness of the high-voltage winding layer.

[0019] In an optional embodiment of the present disclosure, two coils are provided, and the two coils are sequentially sleeved outside the core limb along a length direction of the core limb.

[0020] In an optional embodiment of the present disclosure, the transformer structure further comprises an insulating ring piece, wherein the insulating ring piece is sleeved outside the core limb, and the insulating ring piece is located between the two coils and configured to separate the two coils.

[0021] In addition, according to the transformer structure provided in the embodiment of the present disclosure, a traction transformer for a locomotive can also be provided.

[0022] The present disclosure includes, for example, the following advantageous effects: since a transformer having a transformer structure needs to be placed in an oil tank, when the sum of the cross-sectional areas of the side yokes on any two sides of the core limb is greater than or equal to the cross-sectional area of the core limb, the transformer can be designed with different schemes according to different locomotives, the shape and area of the transformer structure can be adjusted for spatial limitations of different locomotives, and the cross-sectional areas of different side yokes are set by using the cross-sectional area of the core limb as a reference, so that it is easier to match a suitable oil tank, it can be better adapted to a vehicle body structure with great spatial limitation, and the technical problem can be effectively alleviated that the space for the transformer structure in the prior art is greatly limited so that the transformer cannot be placed, and therefore the transformer structure of the present disclosure is more suitable for popularization and use.

Brief Description of Drawings

[0023] In order to more clearly illustrate technical solutions of embodiments of the present disclosure, drawings required for use in the embodiments will be described briefly below. It is to be understood that the drawings below are merely illustrative of some embodiments of the present disclosure, and therefore should not be considered as limiting its scope. It will be understood by those of ordinary skill in the art that other relevant drawings can also be obtained from these drawings without any inventive effort.

FIG. 1 is a schematic overall structural diagram of a transformer structure according to an embodiment of the present disclosure;

FIG. 2 is a schematic structural diagram of a core of a transformer structure according to an embodiment of the present disclosure;

FIG. 3 is a schematic sectional structural diagram of a core of a transformer structure according to an embodiment of the present disclosure; and

FIG. 4 is a schematic structural diagram of a coil of a transformer structure according to an embodiment of the present disclosure.

[0024] Reference Numerals: 100-core; 101-side yoke; 111-first side yoke; 121-second side yoke; 131-third side yoke; 141-fourth side yoke; 102-core limb; 200-coil; 201-traction winding layer; 202-high-voltage winding layer; 203-auxiliary winding layer; 300-accommodating region; 400-chamfer; 500-insulating ring piece.

Detailed Description of Embodiments

[0025] In order to make the objects, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be described below clearly and completely with reference to the drawings of the embodiments of the present disclosure. It is apparent that the embodiments to be described are some, but not all of the embodiments of the present disclosure. Generally, the components of the embodiments of the present disclosure, as described and illustrated in the drawings herein, may be arranged and designed in a wide variety of different configurations.

[0026] Thus, the following detailed description of the embodiments of the present disclosure, as represented in the drawings, is not intended to limit the scope of the present disclosure as claimed, but is merely representative of selected embodiments of the present disclosure. All the other embodiments obtained by those of ordinary skill in the art in light of the embodiments of the present disclosure without inventive efforts will fall within the scope of the present disclosure as claimed.

[0027] It should be noted that similar reference numerals and letters refer to similar items in the following drawings, and thus once an certain item is defined in one drawing, it may not be further defined or explained in the subsequent drawings.

[0028] In the description of the present disclosure, it should be noted that orientation or positional relationships indicated by the terms such as "inside" and "outside" are the orientation or positional relationships shown based on the drawings, or the orientation or positional relationships in which the inventive product is conventionally placed in use, and these terms are intended only to facilitate the description of the present disclosure and simplify the description, but not intended to indicate or imply that the referred devices or elements must be in a particular orientation or constructed or operated in the particular orientation, and therefore should not be construed as limiting the present disclosure. In addition, terms such as "first" and "second" are used for distinguishing the description only, and should not be understood as an indication or implication of relative importance.

[0029] In the description of the present disclosure, it should also be noted that terms "dispose" and "connect" should be understood broadly unless otherwise expressly specified or defined. For example, connection may be fixed connection or detachable connection or integral connection, may be mechanical connection or electric connection, or may be direct linking or indirect linking via an intermediate medium or internal communication between two elements. The specific meanings of the above-mentioned terms in the present disclosure can be understood by those of ordinary skill in the art according to specific situations.

[0030] The transformer structure of the traction transformer in the prior art generally requires two core limbs 102, so that the transformer structure has a relatively large volume, and the space for the transformer will be greatly limited for some locomotive models, thus it will be impossible to place the prior art transformer; and due to the limited characteristics of the transformer structure, the above-mentioned transformer structure can only be applicable to a particular locomotive and is inconveniently popularized. Therefore, the present disclosure provides a transformer structure in response to the technical problems mentioned above.

[0031] As shown in FIGS. 1-4, a transformer structure according to an embodiment of the present disclosure comprises: a core 100 and coils 200; the core 100 comprises side yokes 101 and a core limb 102, the side yokes 101 form an accommodating region 300 configured to close a magnetic circuit, the core limb 102 is disposed in the accommodating region 300, and the coil 200 is sleeved outside the core limb 102 so that the coil 200 is located in the accommodating region 300; and a sum of cross-sectional areas of the side yokes 101 on any two sides of the core limb 102 is greater than or equal to a cross-sectional area of the core limb 102.

[0032] As shown in FIGS. 1-2, the core 100 has a structure being in a shape of Chinese character "

" (a structure shaped like two connected rectangles), a core limb 102 is disposed, and the core limb 102 is fixed in the accommodating region 300 of the side yokes 101, wherein the side yokes 101 are formed by superimposing a plurality of iron pieces in an overlapping manner and the side yokes are mainly used for closing the magnetic circuit, and then the coil 200 is sleeved outside the core limb 102. Based on the structure described above, the shape and the cross-sectional area of the side yokes 101 are limited in the present disclosure, and the magnitude of the cross-sectional area of the side yokes 101 is determined under limitations from the specification of a particular locomotive in such a manner that a sum of the cross-sectional areas of the side yokes 101 on any two sides of the core limb 102 is greater than or equal to the cross-sectional area of the core limb 102, in other words, the core limb 102 is used as a reference for the design of the entire structure, therefore the shape of the core 100 can be adjusted for the locomotive so as to be capable of more easily matching a "suitable oil tank" and meeting the spatial requirements for the oil tanks of most of the locomotives.

[0033] The present disclosure includes, for example, the following advantageous effects: since a transformer having a transformer structure needs to be placed in an oil tank, when the sum of the cross-sectional areas of the side yokes 101 on any two sides of the core limb 102 is greater than or equal to the cross-sectional area of the core limb 102, the transformer can be designed with different schemes according to different locomotives, the shape and area of the transformer structure can be adjusted for spatial limitations of different locomotives, and the cross-sectional areas of different side yokes 101 are set by using the cross-sectional area of the core limb 102 as a reference, so that it is easier to match a suitable oil tank, it can be better adapted to a vehicle body structure with great spatial limitation, and the technical problem can be effectively alleviated that the space for the transformer structure in the prior art is greatly limited so that the transformer cannot be placed, and therefore the transformer structure of the present disclosure is more suitable for popularization and use.

[0034] In an optional embodiment of the present disclosure, the side yokes 101 comprise a first side yoke 111, a second side yoke 121, a third side yoke 131, and a fourth side yoke 141; the first side yoke 111, the second side yoke 121, the third side yoke 131, and the fourth side yoke 141 are sequentially connected in an end-to-end manner, and any two adjacent ones of the first side yoke 111, the second side yoke 121, the third side yoke 131, and the fourth side yoke 141 are disposed perpendicular to each other, such that the accommodating region 300 defined by the first side yoke 111, the second side yoke 121, the third side yoke 131, and the fourth side yoke 141 is in a rectangular shape.

[0035] The accommodating region 300 formed by the first side yoke 111, the second side yoke 121, the third side yoke 131, and the fourth side yoke 141 has a rectangular shape such that the first side yoke 111 is disposed perpendicular to the second side yoke 121, the second side yoke 121 is disposed perpendicular to the third side yoke 131, the third side yoke 131 is disposed perpendicular to the fourth side yoke 141, and the fourth side yoke 141 is disposed perpendicular to the first side yoke 111 to form a rectangular structure of the core 100, and further, the first side yoke 111 and the third side yoke 131 are located on two opposite sides, and the first side yoke 111 and the third side yoke 131 are disposed in parallel, and the second side yoke 121 and the fourth side yoke 141 are also disposed in parallel.

[0036] In an optional embodiment of the present disclosure, the core limb 102 has a circular cross-sectional shape, and each of the first side yoke 111, the second side yoke 121, the third side yoke 131, and the fourth side yoke 141 has a rectangular cross-sectional shape.

[0037] The present disclosure is directed mainly to a transformer structure of a traction transformer for a locomotive, thus the cross-sectional shapes of the core limb 102 and the first side yoke 111, the second side yoke 121, the third side yoke 131, and the fourth side yoke 141 are provided in a preferred mode, and a structural form with a cross-sectional shape in any other conventional technical means that can achieve a closed magnetic circuit is an alternative to the present disclosure.

[0038] In an optional embodiment of the present disclosure, the cross-sectional area of the first side yoke 111 is not equal to the cross-sectional area of the third side yoke 131; and the cross-sectional area of the second side yoke 121 is not equal to the cross-sectional area of the fourth side yoke 141.

[0039] Specifically, the cross-sectional area of the first side yoke 111 may be set as Y1, and the cross-sectional area of the third side yoke 131 may be set as Y2; the cross-sectional area of the second side yoke 121 may be set as S1, and the cross-sectional area of the fourth side yoke 141 may be set as S2, wherein it should be noted that it is defined in the present disclosure that Y1 is not equal to Y2 and S1 is not equal to S2, but Y1 and S1 or S2 may be the same or different, which is not limited herein.

[0040] In an optional embodiment of the present disclosure, a sum of the cross-sectional area of the first side yoke 111 and the cross-sectional area of the third side yoke 131 is greater than or equal to the cross-sectional area of the core limb 102. A sum of the cross-sectional area of the second side yoke 121 and the cross-sectional area of the fourth side yoke 141 is greater than or equal to the cross-sectional area of the core limb 102.

[0041] Optionally, the cross-sectional area of the core limb 102 is set as C, and the core limb 102 and the first side yoke 111, the second side yoke 121, the third side yoke 131, and the fourth side yoke 141 have such a numerical relationship that it should be ensured that Y1≠Y2, S1≠S2, and Y1+Y2≥C, S1+S2≥C. With the above design, in the case where the conditions Y1+Y2≥C and S1+S2≥C are ensured, the cross-sectional dimensions of Y1, Y2, S1, and S2 can be adjusted, so that it is easier to match a "suitable oil tank". Moreover, the above design can meet the requirements of the magnetic circuit of the transformer. A magnetic field is generated after the coil 200 is energized, and magnetic lines form a magnetic circuit through the structure of the core 100, so that the strength of the magnetic field of the whole magnetic circuit is maximized to avoid magnetic leakage loss so as to fulfil the requirement of converting the 25kV high voltage obtained on an overhead line system into a voltage suitable for being supplied for operation of a traction motor and other motors and electrical appliances.

[0042] In an optional embodiment of the present disclosure, the cross-sectional area of the first side yoke 111 or the third side yoke 131 is greater than or equal to a quarter of the cross-sectional area of the core limb 102. The cross-sectional area of the second side yoke 121 or the fourth side yoke 141 is greater than or equal to a quarter of the cross-sectional area of the core limb 102.

[0043] Optionally, on the basis of satisfying the conditions Y1+Y2≥C and S1+S2≥C, the specific numerical values of Y1, Y2, S1, and S2 are set such that it should be ensured that Y1 ≥ a quarter of C, Y2 ≥ a quarter of C, S1 ≥ a quarter of C, and S2 ≥ a quarter of C, since the cross-sectional area C of the core limb 102 is used as a reference for the design of the transformer structure. Illustratively for example, when the magnitude of Y1 is a quarter of C, the minimum value of Y2 should also be greater than or equal to three quarters of C, and similarly, when the magnitude of Y2 is a quarter of C, the minimum value of Y1 should also be greater than or equal to three quarters of C. When the magnitude of S1 is a quarter of C, the minimum value of S2 should also be greater than or equal to three quarters of C, and similarly, when the magnitude of S2 is a quarter of C, the minimum value of S1 should also be greater than or equal to three quarters of C.

[0044] In an optional embodiment of the present disclosure, an outer corner at a position where any two of the first side yoke 111, the second side yoke 121, the third side yoke 131, and the fourth side yoke 141 are connected is provided as a chamfer 400. Since the first side yoke 111, the second side yoke 121, the third side yoke 131, and the fourth side yoke 141 form a rectangular accommodating space, the four corners of the side yokes 101 may be chamfered to form the chamfers 400; preferably, in the case where the magnetic flux density is kept constant, the no-load loss can be reduced, and the weight of the core 100 can be reduced, so that a lightweight and more economical entire transformer structure is implemented.

[0045] In an optional embodiment of the present disclosure, the first side yoke 111 is detachably connected to the second side yoke 121 and the fourth side yoke 141. The first side yoke is used as an openable end, so that when it is necessary to wind the coil 200, the first side yoke may be firstly pulled up, and the coil 200 and an insulating ring piece 500 described later are wrapped around the core limb 102, and then the first side yoke may be connected to the second side yoke 121 and the fourth side yoke 141 by a clamping device. The clamping device acts as a device for connection and fixation in the prior transformer, and therefore will not be described in detail here.

[0046] In an optional embodiment of the present disclosure, the coil 200 comprises a traction winding layer 201, a high-voltage winding layer 202, and an auxiliary winding layer 203; the auxiliary winding layer 203 is sleeved over the high-voltage winding layer 202, and in turn the high-voltage winding layer 202 is sleeved over the traction winding layer 201, with the auxiliary winding layer 203 is located at the outermost layer.

[0047] In an optional embodiment of the present disclosure, the thickness of the auxiliary winding layer 203 is less than the thickness of the traction winding layer 201; and/or the thickness of the auxiliary winding layer 203 is less than the thickness of the high-voltage winding layer 202.

[0048] Optionally, the coil 200 of the embodiment of the present disclosure is arranged in a "traction-high-voltage-auxiliary" manner, and the auxiliary winding layer 203 is placed outside the high-voltage winding layer 202 so that the auxiliary winding layer 203 can be prevented from being affected by a high frequency signal of the traction winding layer 201, and good electromagnetic compatibility is ensured. The auxiliary winding layer 203 is placed on the outermost side. Since the auxiliary winding layer 203 has a lower voltage level, the auxiliary winding layer 203 requires a smaller insulation distance from the bottom or cover of the oil tank or the like, whereby the insulation configuration can be arranged more simply, and further the volume of the transformer to the oil tank can be reduced so as to be better adapted to a vehicle body structure with great spatial limitation, and the weight of the transformer structure is reduced.

[0049] In an optional embodiment of the present disclosure, two coils 200 are provided, and the two coils 200 are sequentially sleeved outside the core limb 102 along the length direction of the core limb 102; further, the transformer structure according to the embodiment of the present disclosure further comprises an insulating ring piece 500; the insulating ring piece 500 is sleeved outside the core limb 102, and the insulating ring piece 500 is located between the two coils 200 and configured to separate the two coils 200.

[0050] In this embodiment, the insulating ring piece 500 may be sprayed with insulating varnish for the transformer structure, and the insulating varnish may be made of an inorganic phosphate film; or an insulating ring piece 500 made of an insulating material may be used, and any insulating ring piece 500 capable of achieving the insulating function of the transformer structure may be used and will not be described in detail here.

[0051] In addition, according to the structure of the transformer structure provided in the embodiment of the present disclosure, a traction transformer for a locomotive can also be provided. Since the traction transformer for a locomotive is operated in a special environment of an electric locomotive, it has a series of characteristics different from an environment in which a general power transformer is operated, which will inevitably be reflected in the actual operation of the traction transformer of the electric locomotive, wherein there are relatively strict restrictions on the outer shape size and the weight, the space in the locomotive body for placement of electrical equipment is very limited, and there are high-power converter devices, high-power motors and the like inside the locomotive, and thus the traction transformer is operated in a strong electromagnetic environment.

[0052] Further, the traction transformer for a locomotive further comprises an oil tank, and the oil tank is generally divided into two layers, one of which is used for placement of a main transformer and the other of which is used for installation of other electric reactor equipment. In addition, the oil tank may also be equipped with auxiliary devices such as lifting lugs, valves, an oil drain plug, a pressure release valve, and a temperature measuring barrel to facilitate the operations such as lifting of the transformer and collection of an oil sample; and a magnetic isolation treatment should be performed between the upper oil tank and the lower oil tank to cut off a magnetic leakage path; and additionally, an oil protection device, a cooling system, a bushing, and transformer oil are also included; wherein the oil protection device, the cooling system, the bushing, and the transformer oil are all specific structures included in the prior art traction transformer for a locomotive and will not be described in detail here.

[0053] The traction transformer for a locomotive according to the embodiment of the present disclosure comprises the transformer structure according to the above embodiment, therefore the cross-sectional dimensions of Y1, Y2, S1 and S2 can be adjusted in the case where the conditions Y1≠Y2, S1≠S2, and Y1+Y2≥C and S1+S2≥C are ensured, such that it is easier to match a "suitable oil tank", and it can be better adapted to a vehicle body structure with great spatial limitation, so that the traction transformer for a locomotive according to the embodiment of the present disclosure is more suitable for popularization.

[0054] The above description is merely illustrative of preferred embodiments of the present disclosure and is not intended to limit the present disclosure. It will be understood by those skilled in the art that various modifications and variations can be made to the present disclosure. Any modifications, equivalent alternatives, improvements and so on made within the spirit and principle of the present disclosure are to be included in the scope of protection of the present disclosure.

Industrial Applicability

[0055] In a transformer structure according to an embodiment of the present disclosure, the transformer structure is set based on the cross-sectional area of a core limb in such a manner that the sum of the cross-sectional areas of side yokes on any two sides of the core limb is greater than or equal to the cross-sectional area of the core limb, so that the transformer structure can more easily match a suitable oil tank and can be better adapted to a vehicle body structure with great spatial limitation.

Claims

1. A transformer structure, characterized by comprising: a core and at least one coil,

wherein the core comprises side yokes and a core limb, the side yokes define an accommodating region configured to close a magnetic circuit, the core limb is disposed in the accommodating region, and the at least one coil is sleeved outside the core limb so that the at least one coil is located in the accommodating region; and

a sum of cross-sectional areas of the side yokes on any two sides of the core limb is greater than or equal to a cross-sectional area of the core limb.

2. The transformer structure according to claim 1, wherein the side yokes comprise a first side yoke, a second side yoke, a third side yoke, and a fourth side yoke; and
the first side yoke, the second side yoke, the third side yoke and the fourth side yoke are sequentially connected in an end-to-end manner, and any two adjacent ones of the first side yoke, the second side yoke, the third side yoke and the fourth side yoke are disposed perpendicular to each other, such that the accommodating region defined by the first side yoke, the second side yoke, the third side yoke and the fourth side yoke is in a rectangular shape.

3. The transformer structure according to claim 2, wherein the core limb has a circular cross-sectional shape, and each of the first side yoke, the second side yoke, the third side yoke and the fourth side yoke has a rectangular cross-sectional shape.

4. The transformer structure according to claim 3, wherein a cross-sectional area of the first side yoke is not equal to a cross-sectional area of the third side yoke.

5. The transformer structure according to claim 4, wherein a cross-sectional area of the second side yoke is not equal to a cross-sectional area of the fourth side yoke.

6. The transformer structure according to claim 4 or 5, wherein a sum of the cross-sectional area of the first side yoke and the cross-sectional area of the third side yoke is greater than or equal to the cross-sectional area of the core limb.

7. The transformer structure according to claim 5 or 6, wherein a sum of the cross-sectional area of the second side yoke and the cross-sectional area of the fourth side yoke is greater than or equal to the cross-sectional area of the core limb.

8. The transformer structure according to claim 6 or 7, wherein the cross-sectional area of the first side yoke or the third side yoke is greater than or equal to a quarter of the cross-sectional area of the core limb.

9. The transformer structure according to claim 7 or 8, wherein the cross-sectional area of the second side yoke or the fourth side yoke is greater than or equal to a quarter of the cross-sectional area of the core limb.

10. The transformer structure according to any one of claims 2 to 9, wherein an outer corner at a position where any two of the first side yoke, the second side yoke, the third side yoke and the fourth side yoke are connected is provided as a chamfer.

11. The transformer structure according to any one of claims 2 to 10, wherein the first side yoke is detachably connected to the second side yoke and the fourth side yoke.

12. The transformer structure according to any one of claims 1 to 11, wherein the at least one coil comprises a traction winding layer, a high-voltage winding layer and an auxiliary winding layer; and
the auxiliary winding layer is sleeved over the high-voltage winding layer, and in turn the high-voltage winding layer is sleeved over the traction winding layer, with the auxiliary winding layer located at an outermost layer.

13. The transformer structure according to claim 12, wherein a thickness of the auxiliary winding layer is less than a thickness of the traction winding layer; and/or the thickness of the auxiliary winding layer is less than a thickness of the high-voltage winding layer.

14. The transformer structure according to any one of claims 1 to 13, wherein two coils are provided, and the two coils are sequentially sleeved outside the core limb along a length direction of the core limb.

15. The transformer structure according to claim 14, further comprising an insulating ring piece, wherein the insulating ring piece is sleeved outside the core limb, and the insulating ring piece is located between the two coils and configured to separate the two coils.

16. A traction transformer for a locomotive, characterized by comprising the transformer structure according to any one of claims 1 to 15.

Drawing