CN112309694A

CN112309694A - Transformer and method for manufacturing the same

Info

Publication number: CN112309694A
Application number: CN201910698032.6A
Authority: CN
Inventors: 应建平; 王亮; 汪强; 刘腾; 曾永; 董建星
Original assignee: Delta Electronics Shanghai Co Ltd
Current assignee: Delta Electronics Shanghai Co Ltd
Priority date: 2019-07-31
Filing date: 2019-07-31
Publication date: 2021-02-02

Abstract

The invention provides a transformer and a manufacturing method thereof. The annular magnetic core has a body portion and a hollow portion, and the hollow portion penetrates through the body portion. At least one first winding is wound around the body portion through the hollow portion. The inner sleeve penetrates through the hollow part. The outer sleeve is sleeved outside the inner sleeve, and the annular magnetic core and the at least one first winding are accommodated between the inner sleeve and the outer sleeve. At least one second winding is wound around the inner and outer sleeves. The inner and outer sleeves separate the at least one first winding from the at least one second winding and separate the at least one second winding from the toroidal core. The invention obviously improves the withstand voltage and partial discharge extinction voltage of the transformer and reduces the volume.

Description

Transformer and method for manufacturing the same

Technical Field

The present disclosure relates to transformers, and more particularly, to a miniaturized transformer with high insulation performance and a method for manufacturing the same.

Background

In recent years, transformers have been widely used in medium-voltage power distribution devices, such as drive and protection of IGBTs, power transformers, and the like. The number of the transformer required by various systems is large during modular design. In order to increase the power density of the application system, the need for miniaturization of the transformer volume is required.

In a low-voltage system, air is often used as an insulating medium for transformer insulation, and the volume of a product is often acceptable due to low insulation level requirements. However, in a medium-voltage system, the requirements on the insulation withstand voltage (voltage) and Partial Discharge (PD) levels of a transformer are high, a conventional medium-voltage transformer mostly adopts a framework to isolate windings with high and low voltages, and air is used as an insulating medium, so that the obtained transformer has a large volume and a low insulation level, and cannot meet the requirements on system performance and power density.

In addition, in the traditional medium-voltage transformer, a die-pressing prefabricated isolation structure is adopted to isolate the high-voltage and low-voltage windings, holes are formed in the prefabricated isolation structure, the pouring sealant enters the interior of the prefabricated isolation structure, and the pouring sealant is poured in the shell in a negative pressure mode. However, the openings in the prefabricated isolation structure are prone to block the flowing of the pouring sealant, are not beneficial to discharging air bubbles inside the mold cavity, and are prone to generating defects inside, so that the application is limited under high voltage.

Therefore, how to develop a transformer with high insulation performance and small volume and a method for manufacturing the same to solve the problems of the prior art is an urgent issue in the field.

Disclosure of Invention

The invention aims to provide a transformer and a manufacturing method thereof. The inner sleeve and the outer sleeve are arranged between the windings, so that the voltage resistance and partial discharge level of the transformer can be improved, the size is further reduced, the competitiveness of a product is improved, and the purposes of simplifying the manufacturing process and reducing the cost are achieved.

Another object of the present invention is to provide a transformer and a method of manufacturing the same. The transformer consists of a first winding, an annular magnetic core, an inner sleeve, an outer sleeve and a second winding. The voltage stress between the first winding and the second winding of the transformer is concentrated, and the first winding and the second winding are separated by the inner sleeve and the outer sleeve, so that the high-voltage insulation performance and the miniaturization of the transformer are realized. And placing the annular magnetic core, the first winding, the second winding and the inner and outer sleeves in the shell, and pouring the pouring sealant. Because the top and the bottom of the annular magnetic core are hollow, the flow resistance of the pouring sealant is small when the pouring sealant is poured, internal bubbles are easy to overflow, and the defects of cracks, bubbles and the like in the transformer are avoided. The transformer uses the inner and outer sleeves as an isolation structure, so that the withstand voltage and partial discharge extinction voltage of the transformer can be obviously improved, the size of the transformer is reduced, and the cost is reduced.

To achieve the above objective, the present invention provides a transformer, which includes a toroidal core, at least one first winding, an inner sleeve, an outer sleeve, and at least one second winding. The annular magnetic core has a body portion and a hollow portion. The hollow portion penetrates the body portion. At least one first winding is wound around the body portion of the annular magnetic core through the hollow portion. The inner sleeve penetrates through the hollow part of the annular magnetic core. The outer sleeve is sleeved outside the inner sleeve, and the annular magnetic core and the at least one first winding are accommodated between the inner sleeve and the outer sleeve. At least one second winding is wound around the inner and outer sleeves. The inner and outer sleeves separate the at least one primary winding from the at least one secondary winding and separate the at least one secondary winding from the toroidal core.

In one embodiment, the body of the toroidal core is ring-shaped or racetrack-shaped and has a rectangular cross-section with at least one chamfered portion.

In one embodiment, the body portion of the toroidal core is annular or racetrack shaped and has a circular cross-section.

In one embodiment, the at least one first winding comprises one first winding wound around the body portion of the toroidal core in a loosely wound manner through the hollow portion.

In one embodiment, the at least one first winding includes a plurality of first windings wound around the body portion of the annular magnetic core in a parallel winding manner or wound around the body portion of the annular magnetic core in a close winding manner through the hollow portion.

In one embodiment, the at least one second winding comprises one second winding wound in a loose-wound manner around the inner and outer sleeves.

In one embodiment, the at least one second winding includes a plurality of second windings wound in a parallel-wound manner around the inner and outer sleeves or wound in a close-wound manner around the inner and outer sleeves.

In one embodiment, both the inner and outer sleeves are made of a soft insulating material.

In an embodiment at least one of the top and bottom of the inner sleeve is provided with at least one flange.

In one embodiment, at least one of the top and bottom of the outer sleeve is provided with at least one flange.

In one embodiment, at least one hole is provided on the side wall of at least one of the inner sleeve and the outer sleeve.

In one embodiment, at least one of the inner surface of the side wall, the top and the bottom of the inner sleeve is provided with at least one limiting groove.

In one embodiment, at least one of the outer surface of the side wall, the top and the bottom of the outer sleeve is provided with at least one limiting groove.

In one embodiment, the inner and outer sleeves are preformed from a wettable material.

In an embodiment, the transformer further includes a housing and a potting adhesive, the housing has a receiving space, the at least one first winding, the toroidal core, the inner sleeve, the outer sleeve and the at least one second winding are received in the receiving space of the housing, the potting adhesive is poured in the receiving space and covers the at least one first winding, the toroidal core, the inner sleeve, the outer sleeve and the at least one second winding, wherein the outgoing line of the at least one first winding and the outgoing line of the at least one second winding are partially exposed outside the potting adhesive.

In one embodiment, an insulating sleeve is sleeved on at least one of the outgoing line of the at least one first winding and the outgoing line of the at least one second winding.

In order to achieve the above object, the present invention provides another method for manufacturing a transformer, including providing an annular magnetic core, wherein the annular magnetic core includes a body portion and a hollow portion, and the hollow portion penetrates through the body portion; providing at least one first winding, and winding around the body part of the annular magnetic core through the hollow part; providing an inner sleeve and an outer sleeve, wherein the inner sleeve penetrates through the hollow part of the annular magnetic core; the outer sleeve is sleeved on the inner sleeve, and an annular magnetic core and at least one first winding are accommodated between the inner sleeve and the outer sleeve; and providing at least one second winding wound around the inner and outer sleeves; wherein the inner and outer sleeves separate the at least one first winding from the at least one second winding and separate the at least one second winding from the toroidal core.

In one embodiment, the method further includes providing a housing having a receiving space, and receiving the at least one first winding, the toroidal core, the inner sleeve, the outer sleeve, and the at least one second winding in the receiving space.

In an embodiment, the method further includes providing a potting adhesive, pouring the accommodating space and coating the at least one first winding, the annular magnetic core, the inner sleeve, the outer sleeve and the at least one second winding, wherein the outgoing lines of the at least one first winding and the outgoing lines of the at least one second winding are partially exposed outside the potting adhesive, and performing the processes of de-bubbling under negative pressure and curing at normal temperature.

In one embodiment, the potting adhesive is defoamed under negative pressure before the potting adhesive is poured into the accommodating space.

In one embodiment, at least one limiting groove is arranged on at least one of the inner surface, the top and the bottom of the side wall of the inner sleeve; or at least one of the outer surface of the side wall, the top and the bottom of the outer sleeve is provided with at least one limiting groove.

Drawings

Fig. 1 is a cross-sectional structural view of a transformer according to a first preferred embodiment of the present disclosure;

FIG. 2 is a method for manufacturing a transformer according to a first preferred embodiment of the present invention;

fig. 3A to 3E are schematic structural diagrams of the transformer according to the first preferred embodiment of the present disclosure at various stages of manufacturing;

fig. 4 is a first exemplary embodiment of the inner and outer sleeves of the transformer in the present case;

fig. 5 is a second exemplary embodiment of the inner and outer sleeves of the transformer in the present case;

fig. 6 is a third exemplary embodiment of the inner and outer sleeves of the transformer in the present case;

fig. 7 is a fourth example of the inner and outer sleeves of the transformer in the present case;

fig. 8 shows a fifth exemplary embodiment of the inner and outer sleeves of the transformer in the present case;

fig. 9 shows a sixth exemplary embodiment of the inner and outer sleeves of the transformer according to the present invention;

fig. 10A shows a seventh exemplary embodiment of the inner and outer sleeves of the transformer in the present case;

FIG. 10B is a cross-sectional view of FIG. 10A;

FIG. 11A is a first exemplary embodiment of a toroidal core in a transformer according to the present invention;

FIG. 11B is a cross-sectional view of FIG. 11A;

FIG. 12A is a second exemplary embodiment of a toroidal core in a transformer according to the present invention;

FIG. 12B is a cross-sectional view of FIG. 12A;

FIG. 13 is a first exemplary embodiment of the present transformer in which a first winding is wound around a toroidal core;

fig. 14A is a second exemplary case where the first winding is wound around the toroidal core in the transformer of the present invention;

FIG. 14B is a top view of FIG. 14A;

fig. 15 is a third exemplary case where the first winding is wound around the toroidal core in the present transformer;

fig. 16 is a fourth exemplary case where the first winding is wound around the toroidal core in the present transformer;

fig. 17 is a schematic structural diagram of a transformer according to a second preferred embodiment of the present invention.

[ List of reference numerals ]

1: transformer device

10. 10 a: annular magnetic core

11: body part

12: hollow part

13: chamfered part

20. 20a, 20b, 20 d: first winding

21. 21a, 21 b: lead-out wire

22. 22a, 22 b: insulating sleeve

30. 30a, 30b, 30c, 30d, 30 e: isolation structure

31: inner sleeve

31a, 31 b: limiting groove

31 c: hole(s)

31 d: flanging

32: outer sleeve

32a, 32b, 32 c: limiting groove

32 d: hole(s)

32e, and (3): flanging

40. 40 a: second winding

41: lead-out wire

42: insulating sleeve

50: outer casing

51: containing space

60: pouring sealant

C1: circular cross section

C2: rectangular cross section

S1-S6: step (ii) of

Detailed Description

Some exemplary embodiments that incorporate the features and advantages of the present disclosure will be described in detail in the specification which follows. It is to be understood that the disclosure is capable of various modifications in various embodiments without departing from the scope of the disclosure, and that the description and drawings are to be regarded as illustrative in nature, and not as restrictive.

Fig. 1 is a cross-sectional structural view of a transformer according to a first preferred embodiment of the present disclosure. Fig. 2 shows a method for manufacturing a transformer according to a first preferred embodiment of the present disclosure. Fig. 3A to 3E are schematic structural diagrams of the transformer according to the first preferred embodiment of the present invention at various stages of manufacturing. In the present embodiment, the transformer 1 includes a toroidal core 10, at least one first winding 20, an inner sleeve 31, an outer sleeve 32, and at least one second winding 40. The annular magnetic core 10 is, for example, a ring, and has a body portion 11 and a hollow portion 12, and the hollow portion penetrates the body portion 12. The at least one first winding 20 is wound around the body 11 of the annular magnetic core 10 in a sparse winding manner through the hollow part 12 of the annular magnetic core 10, and is uniformly distributed on the body 11, which is beneficial to reducing leakage inductance. In this embodiment, the at least one first winding 20 may include 1 first winding, and may also include a plurality of first windings, where the first windings include an enameled wire or a three-layer insulated wire, but is not limited thereto. The inner tube 31 penetrates the hollow portion 12 of the ring-shaped magnetic core 10. The outer sleeve 32 is disposed outside the inner sleeve 31, and the toroidal core 10 and the at least one first winding 20 are accommodated between the inner sleeve 31 and the outer sleeve 32. In the present embodiment, the toroidal core 10 and the body of the at least one first winding 20 are located between the top and bottom, e.g. in the middle, of the inner 31 and outer 32 sleeves; part of the lead-out wire 21 of at least one first winding 20 is accommodated in the space between the inner sleeve 31 and the outer sleeve 32, and another part of the lead-out wire 21 of at least one first winding 20 is located outside the inner sleeve 31 and the outer sleeve 32. In this embodiment, the inner sleeve 31 and the outer sleeve 32 form an insulating isolation structure 30. In the present embodiment, both the inner sleeve 31 and the outer sleeve 32 are made of a soft insulating material, such as rubber; because the soft insulating material has larger friction force, when the annular magnetic core 10 is accommodated between the inner sleeve 31 and the outer sleeve 32, the annular magnetic core 10 can be well fixed at a proper position between the inner sleeve 31 and the outer sleeve 32, so that the manufacturing process of the transformer is simplified. At least one second winding 40 is wound around the inner sleeve 31 and the outer sleeve 32 in a loose winding manner and is uniformly distributed on the inner sleeve 31 and the outer sleeve 32, which is beneficial to reducing leakage inductance, specifically, at least one second winding 40 is wound on the inner surface of the side wall of the inner sleeve 31 and the outer surface of the outer sleeve 32, when the inner sleeve 31 and the outer sleeve 32 are made of soft insulating materials, the top and the bottom of the inner sleeve 31 are turned out towards the annular magnetic core 10 and the top and the bottom of the outer sleeve 32 are turned out towards the annular magnetic core 10 by winding at least one second winding 40 on the inner sleeve 31 and the outer sleeve 32, so that the insulating property of the transformer is improved. In this embodiment, the at least one second winding 40 may include one second winding 40, and may also include a plurality of second windings 40, where the second windings include an enameled wire or a three-layer insulated wire, but is not limited thereto. The inner sleeve 31 and the outer sleeve 32 separate the at least one first winding 20 from the at least one second winding 40 and separate the at least one second winding 40 from the toroidal core 10. In this embodiment, the outgoing line 21 of at least one first winding 20 is sleeved with an insulating sleeve 22, such as a heat-shrinkable sleeve, wherein a part of the insulating sleeve 22 is accommodated in the space between the inner sleeve 31 and the outer sleeve 32, and another part of the insulating sleeve 22 is located outside the inner sleeve 31 and the outer sleeve 32; the lead-out wire 41 of the at least one second winding 40 is sleeved with an insulating sleeve 42, such as a heat-shrinkable sleeve, wherein the insulating sleeve 42 is located outside the inner sleeve 31 and the outer sleeve 32. In other embodiments, an insulating sleeve is sleeved on the pin of one of the at least one first winding 20 and the at least one second winding 40. The transformer 1 further includes a housing 50 having an accommodating space 51 and a potting adhesive 60. The at least one first winding 20, the annular magnetic core 10, the inner sleeve 31, the outer sleeve 32 and the at least one second winding 40 are accommodated in the accommodating space 51, the potting adhesive 60 is poured into the accommodating space 51 under negative pressure and covers the at least one first winding 20, the annular magnetic core 10, the inner sleeve 31, the outer sleeve 32 and the at least one second winding 40, wherein portions of outgoing lines of the at least one first winding 20 and the at least one second winding 40 are exposed outside the potting adhesive 60. In other embodiments, the portion of the at least one first winding 20 around which the insulation sleeve 22 is wrapped and the portion of the at least one second winding 40 around which the insulation sleeve 42 is wrapped around the lead wire 21 are exposed to the potting compound 60. In the embodiment, the potting compound is an epoxy resin or a silicon rubber, but not limited thereto. Under negative pressure, when the pouring sealant 60 is poured, because the tops and the bottoms of the inner sleeve 31 and the outer sleeve 32 are hollow, the pouring sealant 60 has small flow resistance, internal bubbles are easy to overflow, the defects of no cracks and bubbles in the transformer 1 are ensured, the withstand voltage and the partial discharge extinction voltage of the transformer 1 can be obviously improved, and the size of the transformer 1 is reduced.

Based on the transformer 1, the present application further provides a method for manufacturing the transformer 1. Please refer to fig. 1, fig. 2, and fig. 3A to 3E. First, in step S1, a ring-shaped magnetic core 10 is provided, the ring-shaped magnetic core 10 may be, for example but not limited to, a ring, having a body portion 11 and a hollow portion 12, and the hollow portion 12 penetrates through the body portion 11, as shown in fig. 3A. Next, in step S2, at least one first winding 20 is provided and wound around the body portion 11 of the toroidal core 10 through the hollow portion 12, as shown in fig. 3B. Then, in step S3, an inner tube 31 and an outer tube 32 are provided, the inner tube 31 penetrates through the hollow portion 12, the outer tube 32 is sleeved outside the inner tube 31, and the toroidal core 10 and the at least one first winding 20 are accommodated between the inner tube 31 and the outer tube 32, as shown in fig. 3C. Finally, in step S4, at least one second winding 40 is provided and wound around the inner sleeve 31 and the outer sleeve 32, specifically, at least one second winding 40 is wound on the inner surface of the sidewall of the inner sleeve 31 and the outer surface of the sidewall of the outer sleeve 32, as shown in fig. 3D. Next, in step S5, providing the housing 50 having the accommodating space 51, and accommodating the at least one first winding 20, the toroidal core 10, the inner sleeve 31, the outer sleeve 32, and the at least one second winding 40 in the accommodating space 51; then, in step S6, a potting compound 60 is provided, the potting compound 60 is poured into the accommodating space 51 and covers the at least one first winding 20, the toroidal core 10, the inner sleeve 31, the outer sleeve 32 and the at least one second winding 40, wherein the outgoing lines 21 of the at least one first winding 20 and the outgoing lines 41 of the at least one second winding 40 are partially exposed outside the potting compound 60, and the processes of defoaming under negative pressure and curing at normal temperature are completed. In this embodiment, the method for manufacturing a transformer further includes a step of de-bubbling the potting adhesive 60 under negative pressure before pouring the potting adhesive 60 into the accommodating space 51.

The transformer 1 is not limited to the structure of the inner tube 31 and the outer tube 32. In this embodiment, at least one of the inner surface of the sidewall, the top and the bottom of the inner sleeve 31 is provided with a stopper groove. In the present embodiment, at least one of the outer surface of the sidewall, the top and the bottom of the outer sleeve 32 is provided with a limiting groove. In other embodiments, at least one of the top and bottom of inner sleeve 31 is flanged. In other embodiments, at least one of the top and bottom of the outer sleeve 32 is flanged. In other embodiments, at least one hole is provided in the sidewall of at least one of the inner sleeve 31 and the outer sleeve 32. Fig. 4 to 10B are exemplary illustrations of the inner sleeve and the outer sleeve of the transformer, but not limited thereto.

Fig. 4 shows a first example of the inner and outer sleeves of the transformer according to the present invention. The inner sleeve 31 and the outer sleeve 32 form an insulating spacer structure 30. Inner sleeve 31 and outer sleeve 32 are both circular rings, and the tops of inner sleeve 31 and outer sleeve 32 are flush and the bottoms of inner sleeve 31 and outer sleeve 32 are flush. In other embodiments, inner sleeve 31 and outer sleeve 32 are both race track shaped, but not limited thereto. It should be noted that the shapes of the inner sleeve 31 and the outer sleeve 32 are the same as the shape of the toroidal core 10, which can ensure that the electric field distribution of the at least one first winding 20 and the at least one second winding 40 is uniform, and reduce the volume of the transformer. In this embodiment, at least one second winding 40 is wound on the inner surface of the sidewall of the inner sleeve 31 and the outer surface of the sidewall of the outer sleeve 32.

Fig. 5 shows a second exemplary embodiment of the inner and outer sleeves of the transformer. The inner sleeve 31 and the outer sleeve 32 form an insulating spacer structure 30 a. The top and bottom of the inner sleeve 31 are provided with a plurality of retaining grooves 31a, for example, the plurality of retaining grooves 31a are evenly distributed on the top and bottom of the inner sleeve 31. The top and bottom of the outer sleeve 32 are provided with a plurality of stopper grooves 32 a. For example, a plurality of stopper grooves 32a are uniformly distributed at the top and bottom of the outer sleeve 32. The at least one second winding 40 is wound on the inner surface of the side wall of the inner sleeve 31 and the outer surface of the side wall of the outer sleeve 32 and is positioned in the limiting groove 31a and the limiting groove 32a, so that the at least one second winding 40 can be well positioned, the at least one second winding 40 is uniformly distributed, and the leakage inductance is reduced. In other embodiments, the top of the inner sleeve 31 is provided with a plurality of limiting grooves 31a, the bottom of the inner sleeve 31 is not provided with limiting grooves, the bottom of the outer sleeve 32 is provided with a plurality of limiting grooves 32a, and the top of the outer sleeve 32 is not provided with limiting grooves, so that the at least one second winding 40 can be well positioned, the at least one second winding is uniformly distributed, and the leakage inductance is reduced. In other embodiments, a plurality of retaining grooves 31a are provided on the top or bottom of the inner sleeve 31, while neither the top nor the bottom of the outer sleeve 32 is provided with a retaining groove; or the top and the bottom of the inner sleeve 31 are not provided with the limiting grooves, and the bottom or the top of the outer sleeve 32 is provided with the plurality of limiting grooves 32a, but not limited thereto, so that the at least one second winding 40 is distributed in a voltage-sharing manner, and the leakage inductance is small.

Fig. 6 shows a third exemplary embodiment of the inner and outer sleeves of the transformer. The inner sleeve 31 and the outer sleeve 32 form an insulating spacer structure 30 b. The inner sleeve 31 is provided with a plurality of limiting grooves 31b on the inner surface of the side wall, for example, the limiting grooves 31b are uniformly distributed on the inner surface of the side wall of the inner sleeve 31; the outer surface of the top, bottom and side wall of the outer sleeve 32 is provided with a plurality of limiting grooves 32b, for example, a plurality of limiting grooves are uniformly distributed on the outer surface of the top, bottom and side wall of the outer sleeve 32, which helps to position the at least one secondary winding 40, so that the at least one secondary winding 40 is uniformly distributed, and the leakage inductance is reduced. In other embodiments, the inner sleeve 31 has a plurality of limiting grooves 31b on the inner surface, top and bottom of the sidewall, and the outer sleeve 32 has a plurality of limiting grooves 32b on the outer surface of the sidewall, which helps to position the at least one secondary winding 40, so that the at least one secondary winding 40 is uniformly distributed and leakage inductance is reduced.

Fig. 7 shows a fourth example of the inner and outer sleeves of the transformer. The inner sleeve 31 and the outer sleeve 32 form an insulating spacer structure 30 c. The top and the bottom of the inner sleeve 31 are provided with a plurality of limiting grooves 31a, for example, the plurality of limiting grooves 31a are uniformly distributed on the top and the bottom of the inner sleeve 31; the outer surface of the sidewall of the outer sleeve 32 is provided with a plurality of limiting grooves 32c, for example, a plurality of limiting grooves are uniformly distributed on the outer surface of the sidewall of the outer sleeve 32, which is helpful for positioning the at least one secondary winding 40, so that the at least one secondary winding 40 is uniformly distributed, and the leakage inductance is reduced.

Fig. 8 shows a fifth exemplary embodiment of the inner and outer sleeves of the transformer. The inner sleeve 31 and the outer sleeve 32 form an insulating spacer structure 30 d. The inner sleeve 31 is provided with a plurality of limiting grooves 31b on the inner surface of the side wall, for example, the limiting grooves 31b are uniformly distributed on the inner surface of the side wall of the inner sleeve 31; the outer surface of the sidewall of the outer sleeve 32 is provided with a plurality of limiting grooves 32c, for example, a plurality of limiting grooves are uniformly distributed on the outer surface of the sidewall of the outer sleeve 32, which is helpful for positioning the at least one secondary winding 40, so that the at least one secondary winding 40 is uniformly distributed, and the leakage inductance is reduced.

In other embodiments, the limiting grooves may be disposed on the inner surfaces of the top, bottom and side walls of the inner sleeve 31 and the outer surfaces of the top, bottom and side walls of the outer sleeve 32 as required, and are not limited to the technical solutions described in fig. 5 to 8.

Fig. 9 shows a sixth exemplary embodiment of the inner and outer sleeves of the transformer. The inner sleeve 31 and the outer sleeve 32 form an insulating spacer structure 30 e. When the inner sleeve 31 and the outer sleeve 32 are poured with the pouring sealant, the holes 31c in the inner sleeve 31 and the holes 32d in the outer sleeve 32 help to discharge bubbles, and defects such as cracks and bubbles in the transformer are avoided. In other embodiments, a hole is provided on the side wall of the inner sleeve 31 and the outer sleeve 32; at least one hole is provided on the side wall of the inner sleeve 31 or the outer sleeve 32, but not limited thereto.

Fig. 10A shows a seventh exemplary embodiment of the inner and outer sleeves of the transformer. Fig. 10B is a cross-sectional view of fig. 10A. The top and the bottom of the inner sleeve 31 are both provided with flanges 31d, wherein the flanges 31d are turned out towards the outer surface of the side wall of the inner sleeve 31, the top and the bottom of the outer sleeve 32 are both provided with flanges 32e, and the flanges 32e are turned out towards the inner surface of the side wall of the outer sleeve 32, so that the insulation performance of the transformer can be improved. In other embodiments, the top or bottom of the inner sleeve 31 is provided with a flange 31d, and the top or bottom of the outer sleeve 32 is provided with a flange 32 e; or the top of the inner sleeve 31 and the bottom of the outer sleeve 32 are provided with flanges; or the bottom of the inner sleeve 31 and the top of the outer sleeve 32 are provided with flanges, but not limited thereto.

Fig. 11A is a first exemplary embodiment of a toroidal core in a transformer according to the present invention. Fig. 11B is a cross-sectional view of fig. 11A. In the embodiment, the ring-shaped magnetic core 10 is a circular ring, and includes a body portion 11 and a hollow portion 12, and has a rectangular cross section C2, and the rectangular cross section C2 further has at least one chamfered portion 13, for example, four straight corners of the rectangular cross section have chamfered portions. In other embodiments, the toroidal core 10 is racetrack shaped, having a rectangular cross-section with at least one chamfered portion. In the embodiment, the chamfer portion 13 is disposed to improve the electric field distribution on the surface of the high-low voltage winding formed by the at least one first winding 20 and the at least one second winding 40, reduce the maximum field strength value on the surface of the winding, increase the withstand voltage and the partial discharge extinction voltage of the transformer, reduce the volume of the transformer, and reduce the cost.

Fig. 12A is a second exemplary embodiment of a toroidal core in the present transformer. Fig. 12B is a cross-sectional view of fig. 12A. In the embodiment, the toroidal core 10a is a circular ring, and includes the body portion 11 and the hollow portion 12, and has a circular cross section C1, so that the electric field distribution of the at least one first winding 20 and the at least one second winding 40 can be improved, the partial discharge and withstand voltage level can be improved, and the volume of the transformer structure can be further reduced. In other embodiments, the magnetic core is racetrack shaped, having a circular cross-section.

In addition, it should be noted that the transformer 1 does not limit the winding method of the at least one first winding 20 and the at least one second winding 40. In this embodiment, the at least one first winding 20 includes one first winding 20, and the first winding 20 is wound around the body portion 11 of the toroidal transformer in a loosely wound manner around the hollow portion 12. In other embodiments, the at least one first winding 20 includes a plurality of first windings 20, the plurality of first windings 20 are wound around the body portion 11 of the toroidal core 10 in a wound-around manner through the hollow portion 12, or the plurality of first windings 20 are wound around the body portion 11 of the toroidal core 10 in a close-wound manner through the hollow portion 12. In other embodiments, the at least one second winding 40 comprises one second winding wound around the body portion 11 of the toroidal transformer in a loose-wound manner around the hollow portion 12. In other embodiments, the at least one second winding 40 includes a plurality of second windings 40, the plurality of second windings 40 are wound around the body portion 11 of the toroidal core 10 in a wound manner through the hollow portion 12, or the plurality of second windings 40 are wound around the body portion 11 of the toroidal core 10 in a close-wound manner through the hollow portion 12. The present application is not limited thereto.

Fig. 13 shows a first exemplary case where the first winding is wound around the toroidal core in the present transformer. In the present embodiment, the at least one first winding 20 further includes two

first windings

20a and 20b, an insulating sleeve 22a, such as a heat-shrinkable sleeve, is sleeved outside the two outgoing lines 21a of the first winding 20a, and an insulating sleeve 22b, such as a heat-shrinkable sleeve, is sleeved outside the two outgoing lines 21b of the first winding 20b, and are spatially opposite to each other, which is beneficial to increase a creepage distance and improve the insulating performance of the

outgoing lines

21a and 21 b. The insulating

sleeves

22a, 22b each have two mutually isolated passages, each of which is traversed by a respective outlet line. In other embodiments, each lead-out wire is sleeved with an insulating sleeve. In the present embodiment, the

first windings

20a and 20b are uniformly distributed in the body portion 11 of the annular magnetic core 10 in a loosely wound manner, which helps to reduce leakage inductance.

Fig. 14A is a second exemplary case where the first winding is wound around the toroidal core in the transformer of the present invention. Fig. 14B is a top view of fig. 14A. In the present embodiment, the at least one first winding 20 further includes two

first windings

20a and 20b, which are wound on the main body 12 of the annular magnetic core 10a in a close-wound manner through the hollow portion 12, and the

first windings

20a and 20b have a certain distance therebetween.

Fig. 15 shows a third exemplary case where the first winding is wound around the toroidal core in the present transformer. The at least one first winding 20 further includes two

first windings

20a and 20b wound around the body 11 of the toroidal core 10a through the hollow portion 12 in a parallel winding manner, and the

first windings

20a and 20b are uniformly distributed on the body 11, which helps to reduce leakage inductance.

Fig. 16 shows a fourth exemplary case where the first winding is wound around the toroidal core in the present transformer. The at least one first winding 20 further includes a first winding 20d wound around the body portion 11 of the toroidal core 10 in a close-wound manner through the hollow portion 12.

While the above description describes the specific embodiment in which the at least one first winding 20 is wound around the body portion of the toroidal core, it should be noted that the at least one second winding 40 may also be wound around the inner sleeve and the outer sleeve according to the winding manner of the at least one first winding 20, which is not described herein again.

Fig. 17 is a schematic structural diagram of a transformer according to a second preferred embodiment of the present invention. The at least one first winding 20d includes a first winding and the at least one second winding 40a includes a second winding. The toroidal core 10 includes a body portion 11 and a hollow portion 12, and the hollow portion 12 penetrates the body portion 11. The first winding 20d is wound around the body portion 11 in a close-wound manner through the hollow portion 12. The inner tube 31 penetrates the hollow portion 12, the outer tube 32 is sleeved on the inner tube 31, the annular magnetic core 10 and the first winding 20d are accommodated between the inner tube 31 and the outer tube 32, and the second winding 40a is wound around the inner tube 31 and the outer tube 32 in a close-wound manner. The inner sleeve 31 and the outer sleeve 32 are preformed from a wettable material to form an insulating isolation structure, and the annular magnetic core 10 is positioned between the top and the bottom of the inner sleeve 31 and the outer sleeve 32, so that the volume of the transformer is reduced, the manufacturing process is simplified, and the production cost is reduced.

In summary, embodiments of the present disclosure provide a transformer and a method for manufacturing the same. The inner sleeve and the outer sleeve are arranged between the windings, so that the voltage resistance and partial discharge level can be improved, the size is further reduced, the competitiveness of a product is improved, and the aims of simplifying the manufacturing process and reducing the production cost are fulfilled. In addition, the transformer consists of a first winding, an annular magnetic core, a second winding, an inner sleeve, an outer sleeve, pouring sealant and a shell. Because the top and the bottom of the inner sleeve and the outer sleeve are hollow, after pouring the pouring sealant under negative pressure, bubbles in the transformer can overflow, and the defects of cracks, bubbles and the like in the transformer are further overcome. The winding isolation method used by the transformer can obviously improve the withstand voltage and the partial discharge extinction voltage of the transformer, reduce the volume of the transformer and reduce the cost.

It should be noted that the above-mentioned embodiments illustrate only preferred embodiments of the disclosure, and the disclosure is not limited to the described embodiments, as the scope of the disclosure is determined by the claims. And that this disclosure will be modified by those skilled in the art as deemed to be within the scope and spirit of the appended claims.

Claims

1. A transformer, comprising:

an annular magnetic core having a body portion and a hollow portion, the hollow portion penetrating the body portion;

at least one first winding wound around the body portion of the toroidal core through the hollow portion;

an inner sleeve penetrating the hollow part of the annular magnetic core;

the outer sleeve is sleeved outside the inner sleeve, and the annular magnetic core and the at least one first winding are accommodated between the inner sleeve and the outer sleeve; and

at least one second winding wound around the inner and outer sleeves;

wherein the inner sleeve and the outer sleeve separate the at least one first winding from the at least one second winding and separate the at least one second winding from the toroidal core.

2. The transformer of claim 1, wherein the body portion of the toroidal core is annular or racetrack shaped and has a rectangular cross-section with at least one chamfered portion.

3. The transformer of claim 1, wherein the body portion of the toroidal core is annular or racetrack shaped and has a circular cross-section.

4. The transformer of claim 1, wherein the at least one first winding comprises one first winding that is wound around the body portion of the toroidal core in an open-wound manner through the hollow portion.

5. The transformer of claim 1, wherein the at least one first winding comprises a plurality of first windings passing through the hollow portion and wound in a parallel-wound manner around the body portion of the toroidal core or wound in a close-wound manner around the body portion of the toroidal core.

6. The transformer according to claim 4 or 5, wherein the at least one second winding comprises one second winding wound in a loose-wound manner around the inner and outer sleeves.

7. The transformer according to claim 4 or 5, wherein the at least one second winding comprises a plurality of second windings, the plurality of second windings being wound around the inner and outer sleeves in a parallel winding manner or wound around the inner and outer sleeves in a close-wound manner.

8. The transformer according to claim 1, wherein the inner and outer sleeves are made of a soft insulating material.

9. The transformer according to claim 1, wherein at least one of the top and bottom of the inner sleeve is provided with at least one flange.

10. The transformer according to claim 1 or 9, wherein at least one of the top and bottom of the outer sleeve is provided with at least one flange.

11. The transformer according to claim 1, wherein at least one hole is provided in at least one of the side walls of the inner and outer sleeves.

12. The transformer according to claim 1, wherein at least one of the inner side wall surface, the top portion and the bottom portion of the inner bushing is provided with at least one limiting groove.

13. The transformer according to claim 1 or 11, wherein at least one of the outer surface of the side wall, the top and the bottom of the outer sleeve is provided with at least one limiting groove.

14. The transformer of claim 1, wherein said inner and outer sleeves are preformed from a wettable material.

15. The transformer of claim 1, further comprising a housing and a potting compound, the housing having a receiving space, wherein the at least one first winding, the toroidal core, the inner sleeve, the outer sleeve, and the at least one second winding are received in the receiving space of the housing, the potting compound is poured into the receiving space and covers the at least one first winding, the toroidal core, the inner sleeve, the outer sleeve, and the at least one second winding, and wherein portions of the lead-out wires of the at least one first winding and the lead-out wires of the at least one second winding are exposed outside of the potting compound.

16. The transformer of claim 15, wherein at least one of the lead-out wire of the at least one first winding and the lead-out wire of the at least one second winding is sheathed with an insulating sleeve.

17. A method of manufacturing a transformer, comprising:

providing an annular magnetic core, wherein the annular magnetic core comprises a body part and a hollow part, and the hollow part penetrates through the body part;

providing at least one first winding wound around the body portion of the toroidal core through the hollow portion;

providing an inner sleeve and an outer sleeve, wherein the inner sleeve penetrates through the hollow part of the annular magnetic core; the outer sleeve is sleeved on the inner sleeve, and the annular magnetic core and the at least one first winding are accommodated between the inner sleeve and the outer sleeve; and

providing at least one second winding wound around the inner and outer sleeves;

18. The method of claim 17, further comprising providing an outer housing having a receiving space and receiving the at least one first winding, the toroidal core, the inner sleeve, the outer sleeve, and the at least one second winding in the receiving space.

19. The method according to claim 18, further comprising providing a potting compound, pouring the accommodating space and covering the at least one first winding, the toroidal core, the inner sleeve, the outer sleeve, and the at least one second winding, wherein portions of the lead-out wires of the at least one first winding and the lead-out wires of the at least one second winding are exposed outside the potting compound, and performing de-bubbling under negative pressure and curing at room temperature.

20. The method according to claim 19, wherein the potting adhesive is deaerated under negative pressure before the potting adhesive is poured into the accommodating space.

21. The method of claim 17, wherein at least one of the inner surface of the side wall, the top and the bottom of the inner sleeve is provided with at least one limiting groove; or at least one of the outer surface of the side wall, the top and the bottom of the outer sleeve is provided with at least one limiting groove.

22. The method of claim 17, wherein at least one of the top and bottom portions of the inner sleeve is provided with at least one flange.

23. The method of claim 17 or 23, wherein at least one of the top and bottom of the outer sleeve is provided with at least one flange.