A balanced winding design method for a transformer and a transformer

Abstract

The application discloses a balanced winding design method of a transformer and the transformer. The transformer comprises a first primary winding, a balanced winding, a secondary winding and a second primary winding which are sequentially laid from inside to outside. One end of the balanced winding is connected with one end of the second primary winding, and the other end of the second primary winding is connected with the first primary winding. The balanced winding design method comprises the following steps: obtaining a first structural capacitance between the second primary winding and the secondary winding, a second structural capacitance between the balanced winding and the secondary winding, the number of turns of the second primary winding and the number of turns of the secondary winding; and calculating the number of turns of the balanced winding according to the first structural capacitance, the second structural capacitance, the number of turns of the second primary winding and the number of turns of the secondary winding. The leakage inductance and the power loss of the transformer are reduced through interleaved winding. The number of turns of the balanced winding is obtained through simple calculation, so that the time is shortened and the calculation error is reduced. The transformer is provided with the balanced winding to reduce the conducted noise and reduce the volume of the transformer.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of transformers, in particular to a balanced winding design method of a transformer and the transformer. BACKGROUND

[0002] In an isolated switching power supply, the common-mode electromagnetic interference (EMI) characteristic of a transformer is an important index for judging the electromagnetic compatibility performance. With the popularization and application of silicon carbide (SiC) devices and wide-bandgap power electronic devices, the switching frequency and resonance frequency of the switching power supply have been improved, which makes the common-mode EMI characteristic of the transformer a direct factor for determining the electromagnetic compatibility performance.

[0003] The conventional shielding method of a flyback converter is to add a single layer of shielding copper foil between the primary and secondary windings of the transformer and connect it to the input positive bus, but this method needs to adjust the negative induced charge generated by the primary winding on the secondary winding by constantly changing the window height of the copper foil to offset the common-mode noise. However, for a flyback converter using synchronous rectification on the secondary side, the superposition of the negative charge common-mode current induced on the secondary winding of the transformer due to the low point position of the moving point cannot achieve the offset of the common-mode noise. The common method for this situation is to add an external reverse auxiliary winding to lower the point position of the shielding copper foil, but this approach is not conducive to reducing the size and cost of the transformer, and the leakage inductance is also relatively large, which increases the loss of the transformer. SUMMARY

[0004] The embodiments of the present application provide a balanced winding design method of a transformer and the transformer to solve the problems of large leakage inductance and size and high cost of the transformer in the conventional shielding method.

[0005] To achieve the above purpose, in an embodiment, a balanced winding design method of a transformer is provided, the transformer comprising a first primary winding, a balanced winding, a secondary winding and a second primary winding which are sequentially laid from inside to outside, one end of the balanced winding being connected to one end of the second primary winding, and the other end of the second primary winding being connected to the first primary winding; the balanced winding design method comprising:

[0006] obtaining a first structural capacitance between the second primary winding and the secondary winding, a second structural capacitance between the balanced winding and the secondary winding, the number of turns of the second primary winding and the number of turns of the secondary winding;

[0007] calculating the number of turns of the balanced winding according to the first structural capacitance, the second structural capacitance, the number of turns of the second primary winding and the number of turns of the secondary winding.

[0008] In an embodiment, a calculation expression of the number of turns of the balance winding is calculated according to the first structural capacitance, the second structural capacitance, the number of turns of the second primary winding and the number of turns of the secondary winding as follows:

[0009] ,

[0010] wherein, N is the number of turns of the balance winding, C1 is the first structural capacitance, C2 is the second structural capacitance, N2 is the number of turns of the second primary winding, N3 is the number of turns of the secondary winding.

[0011] In an embodiment, the balance winding is wound around a longitudinal window space of the transformer, so that a winding height of the balance winding is equal to winding heights of the secondary winding and the second primary winding.

[0012] In an embodiment, the first structural capacitance is obtained by:

[0013] obtaining a coil radius of the secondary winding, a winding height of the secondary winding, a first interlayer distance between the second primary winding and the secondary winding;

[0014] calculating the first structural capacitance according to the coil radius of the secondary winding, the winding height of the secondary winding and the first interlayer distance between the second primary winding and the secondary winding.

[0015] In an embodiment, a calculation expression of the first structural capacitance is calculated as follows:

[0016] ,

[0017] wherein, C1 is the first structural capacitance, ε0 is a vacuum medium constant, εeff is an equivalent medium constant of an interlayer insulation material of the second primary winding and the secondary winding, R3 is the coil radius of the secondary winding, H3 is the winding height of the secondary winding, d1 is the first interlayer distance.

[0018] In an embodiment, the second structural capacitance is obtained by:

[0019] obtaining a coil radius of the balance winding, a winding height of the secondary winding, a second interlayer distance between the balance winding and the secondary winding;

[0020] The second structural capacitance is calculated according to a coil radius of the balance winding, a winding height of the secondary winding, and a second interlayer distance between the balance winding and the secondary winding.

[0021] In an embodiment, a calculation expression for calculating the second structural capacitance is:

[0022] ,

[0023] wherein, C2 is the second structural capacitance, ε0 is a vacuum medium constant, εr is an equivalent medium constant of an interlayer insulation material of the balance winding and the secondary winding, R is a coil radius of the balance winding, H is a winding height of the secondary winding, d2 is the second interlayer distance.

[0024] In an embodiment, calculating the number of turns of the balance winding according to the first structural capacitance, the second structural capacitance, the number of turns of the second primary winding, and the number of turns of the secondary winding comprises:

[0025] calculating a sum of the number of turns of the first primary winding and the number of turns of the second primary winding to obtain a total number of turns of the primary winding;

[0026] determining a first function relationship between a first displacement current and the first structural capacitance, the total number of turns of the primary winding, the number of turns of the second primary winding, and the number of turns of the secondary winding;

[0027] determining a second function relationship between a second displacement current and the second structural capacitance, the total number of turns of the primary winding, the number of turns of the balance winding, and the number of turns of the secondary winding;

[0028] determining a correspondence between the total displacement current of the transformer and the first function relationship and the second function relationship;

[0029] setting the total displacement current of the transformer to zero according to the first function relationship, the second function relationship, and the correspondence, and calculating the number of turns of the balance winding.

[0030] In an embodiment, a transformer is provided, which comprises a first primary winding, a balance winding, a secondary winding, and a second primary winding, which are sequentially laid from inside to outside, one end of the balance winding is connected to one end of the second primary winding, the other end of the second primary winding is connected to the first primary winding, and the balance winding is obtained by using the above balance winding design method.

[0031] In an embodiment, the transformer further comprises an insulating tape arranged between each layer of winding, the second primary winding and the secondary winding are both wound around the longitudinal window space of the transformer, and the winding height of the balance winding is equal to the winding height of the second primary winding and the secondary winding.

[0032] The balance winding design method and the transformer of the transformer have the advantages that the windings are sequentially laid from inside to outside to realize interleaved winding, the leakage inductance of the transformer is reduced, the power loss of the transformer is reduced, the specific balance winding is set according to the first structure capacitor, the second structure capacitor, the number of turns of the second primary winding and the number of turns of the secondary winding, the balance winding can shield the electric field coupling effect of the primary side and the secondary side, and can realize the function of completely balancing the common-mode displacement current of the primary side and the secondary side of the transformer, the conductive noise can be reduced in combination with the interleaved winding, compared with the traditional method of setting a single layer of shielding copper foil and additionally arranging a reverse winding, the volume of the transformer can be reduced, and the manufacturing cost can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the description of the embodiments of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0034] Figure 1 is a winding diagram of each winding of the transformer in an embodiment of the present application;

[0035] Figure 2 is a displacement current interference transmission path diagram in an embodiment of the present application;

[0036] Figure 3 is a flowchart of the balance winding design method in an embodiment of the present application;

[0037] Figure 4 is a schematic diagram of a traditional low-end synchronous rectification flyback converter adding a single layer of copper foil and additionally arranging a reverse winding to balance the displacement current;

[0038] Figure 5 is a flowchart of calculating the number of turns of the balance winding in the balance winding design method in an embodiment of the present application;

[0039] Figure 6 is a schematic diagram of voltage values corresponding to different winding heights in an embodiment of the present application.

[0040] The drawings show that: 1 is a No. 1 terminal of the transformer, 2 is a No. 2 terminal of the transformer, 3 is a No. 3 terminal of the transformer, 4 is a No. 4 terminal of the transformer, 5 is a No. 5 terminal of the transformer, 6 is a No. 6 terminal of the transformer, and 7 is an insulating tape. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of the present application.

[0042] It should be understood that the present application can be implemented in various forms and should not be interpreted in a limited way based on the embodiments presented herein. On the contrary, these embodiments are presented in order to make the disclosure complete and full, and to fully convey the scope of the present application to those skilled in the art. In the drawings, the sizes and relative sizes of layers and regions can be exaggerated for clarity throughout the drawings, and the same reference numbers represent the same elements.

[0043] It should be understood that when an element or layer is referred to as being "on", "adjacent", "connected to", or "coupled to" another element or layer, it can be directly on, adjacent, connected or coupled to the other element or layer, or an intervening element or layer can be present. In contrast, when an element is referred to as being "directly on", "directly adjacent", "directly connected to", or "directly coupled to" another element or layer, then there are no intervening elements or layers present. It will be understood that, although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Therefore, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present application.

[0044] Spatial relationship terms, such as "below", "under", "lower", "underneath", "above", "upper", and the like, can be used herein for ease of description to describe the relationship of one element or feature to another element(s) or feature(s) as illustrated in the drawings. It will be understood that the spatial relationship terms are also intended to include different orientations of the device in use and / or operation in addition to the orientation depicted in the drawings. For example, if the device in the drawings is turned over, then the element or feature that is described as "below" or "under" or "underneath" another element or feature would then be oriented "above" the other element or feature. Thus, the exemplary term "below" and "under" can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatial descriptions used herein interpreted accordingly.

[0045] The purpose of the terms used herein is only to describe specific embodiments and is not intended to limit the present invention. When used herein, the singular forms "a", "an", and "the" are intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "comprising" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0046] In order to fully understand the present invention, detailed structures and steps will be provided in the following description to illustrate the technical solutions proposed by the present invention. Preferred embodiments of the present invention are described in detail below. However, in addition to these detailed descriptions, the present invention may also have other implementations.

[0047] In one embodiment, a method for designing a balanced winding of a transformer is provided, such as Figure 1 and Figure 2 As shown, the transformer includes a first primary winding laid out from the inside to the outside. , Balance Winding , secondary winding , second primary winding , the balance winding One end of the second primary winding One end of the second primary winding is connected to The other end of the first primary winding connected; such as Figure 3 As shown, the balanced winding design method includes:

[0048] S101, obtaining the second primary winding and the secondary winding The first structural capacitance between , the balance winding and the secondary winding The second structure capacitance between , the second primary winding Number of turns and the secondary winding Number of turns ;

[0049] Among them, the balance winding can not only shield the electric field coupling between the primary and secondary sides, but also achieve the function of fully balancing the common-mode displacement current of the primary and secondary sides of the transformer;

[0050] like Figure 2 As shown, the first structure capacitance Refers to the second primary winding and the secondary winding The equivalent capacitance between the second structure capacitance Refers to the balanced winding and the secondary winding The equivalent capacitance between the first structure and the capacitance The second primary winding and the secondary winding The equivalent capacitance coupled to the second structure capacitance For balanced winding and the secondary winding Equivalent capacitance coupled to, first structure capacitance and the second structure capacitance These are not actual capacitors.

[0051] S102, according to the first structure capacitor The second structure capacitor , the number of turns of the second primary winding and the number of turns of the secondary winding Calculate the number of turns of the balance winding .

[0052] Among them, the first structural capacitance obtained , the second structure capacitor , the number of turns of the second primary winding and the number of turns of the secondary winding Substituting the first structural capacitance, the second structural capacitance, the number of turns of the second primary winding, the number of turns of the secondary winding, and the number of turns of the balance winding into the relationship model, the number of turns of the balance winding is obtained.

[0053] like Figure 1 As shown, an auxiliary winding is also provided in the transformer , auxiliary winding Located in the first primary winding The outer and balance windings On the inside of the transformer, each winding is set in an interleaved winding manner.

[0054] In this embodiment, staggered winding is achieved by laying the windings sequentially from the inside to the outside, making full use of the space between the windings, making the structure of the transformer more compact, and at the same time reducing electromagnetic wave interference, reducing the leakage inductance of the transformer and reducing power loss. A specific balanced winding is set according to the first structure capacitor, the second structure capacitor, the number of turns of the second primary winding and the number of turns of the secondary winding, which can shield the electric field coupling effect of the primary and secondary sides and achieve the function of fully balancing the common-mode displacement current of the primary and secondary sides of the transformer. Combined with staggered winding, the conducted noise can be reduced. Figure 4Compared with the conventional structure of arranging a single-layer shielding copper foil and adding a reverse winding, the transformer of the present application can reduce the volume and manufacturing cost of the transformer.

[0055] In one embodiment, the calculation expression of the number of turns of the balance winding is calculated according to the first structure capacitance, the second structure capacitance, the number of turns of the second primary winding and the number of turns of the secondary winding as follows:

[0056] ,

[0057] wherein, the number of turns of the balance winding, the first structure capacitance, the second structure capacitance, the number of turns of the second primary winding, the number of turns of the secondary winding.

[0058] The electric field intensity in the transformer winding is closely related to the number of turns of the winding. The more the number of turns, the greater the electric field intensity. Since the structure capacitance is proportional to the electric field intensity, the increase of the electric field intensity will result in the enhancement of the capacitance effect between the windings.

[0059] In the present embodiment, the number of turns of the balance winding is calculated according to the first structure capacitance, the second structure capacitance, the number of turns of the second primary winding and the number of turns of the secondary winding, so that the calculation is more accurate, the error and uncertainty in the design process are reduced, the electromagnetic compatibility of the transformer can be changed, which is helpful to reduce the electromagnetic interference of the transformer and improve the service life and safety of the transformer; by adjusting the number of turns, the manufacturing process of the transformer is simplified, and different requirements are met.

[0060] In one embodiment, as Figure 1 shown, the balance winding is wound around the longitudinal window space of the transformer, so that the winding height of the balance winding is equal to the winding height of the secondary winding and the second primary winding .

[0061] As Figure 1 shown, the longitudinal window space refers to the area on the transformer magnetic core for winding the coil, that is, the space provided in the longitudinal direction. The winding height refers to the longitudinal vertical distance of the coil on the transformer magnetic core skeleton from the starting end to the terminal end, which can also refer to the cumulative height of the number of turns of the winding. The longitudinal window space and the winding height appearing below have the same meaning, and will not be repeated hereinafter.

[0062] The balance winding The winding height of the balance winding refers to the vertical distance of the balance winding from the starting end to the ending end on the transformer core skeleton, or the cumulative height of all the turns of the balance winding on the core skeleton. The secondary winding And the second primary winding All wind the longitudinal window space of the transformer, and the winding height of the balance winding, the secondary winding and the second primary winding are equal.

[0063] In this embodiment, the balance winding, the secondary winding and the second primary winding all wind the longitudinal window of the transformer, ensuring that the magnetic flux is evenly distributed between the windings, thereby improving the electromagnetic conversion efficiency, reducing the generation of electromagnetic interference (EMI), and improving the electromagnetic compatibility of the transformer. The close winding design can reduce the uneven distribution of current in the winding, thereby reducing energy loss, and can maintain stable output of current and voltage, thereby ensuring the reliability of the transformer in long-term operation.

[0064] In an embodiment, i.e., step S101 described above, the first structural capacitance is obtained, including:

[0065] Obtaining the coil radius of the secondary winding, the winding height of the secondary winding, and the first interlayer distance between the second primary winding and the secondary winding;

[0066] According to the coil radius of the secondary winding, the winding height of the secondary winding, and the first interlayer distance between the second primary winding and the secondary winding, the calculation expression of the first structural capacitance is calculated as:

[0067] ,

[0068] wherein, is the first structural capacitance, is the vacuum medium constant, is the equivalent medium constant of the interlayer insulation material of the second primary winding and the secondary winding, is the coil radius of the secondary winding, is the winding height of the secondary winding, is the first interlayer distance.

[0069] In this embodiment, by establishing a relationship model for representing the first structural capacitance and the coil radius of the secondary winding, the winding height of the secondary winding and the first interlayer distance, the parameters are substituted into the relationship model, and the first structural capacitance can be accurately calculated to more accurately obtain the number of turns of the balance winding, and to deepen the shielding effect of the balance winding and the effect of offsetting the common-mode displacement current.

[0070] In an embodiment, the second structural capacitance is obtained in step S101, comprising:

[0071] obtaining the coil radius of the balance winding, the winding height of the secondary winding, and the second interlayer distance between the balance winding and the secondary winding;

[0072] The calculation expression of the second structural capacitance is calculated according to the coil radius of the balance winding, the winding height of the secondary winding, and the second interlayer distance between the balance winding and the secondary winding, and is as follows:

[0073]

[0074] wherein, is the second structural capacitance, is the vacuum medium constant, is the equivalent medium constant of the interlayer insulation material of the balance winding and the secondary winding, is the coil radius of the balance winding, is the winding height of the secondary winding, is the second interlayer distance.

[0075] In the embodiment, the relationship model between the second structural capacitance and the coil radius of the balance winding, the winding height of the secondary winding, and the second interlayer distance is established, and the parameters are substituted into the relationship model, so that the second structural capacitance can be accurately calculated, and the number of turns of the balance winding can be more accurately obtained, so that the shielding effect of the balance winding and the effect of offsetting the common-mode displacement current are deepened.

[0076] In an embodiment, the number of turns of the balance winding is calculated according to the first structural capacitance, the second structural capacitance, the number of turns of the second primary winding, and the number of turns of the secondary winding in step S102, and the calculation comprises: Figure 5

[0077] S801, calculating the sum of the number of turns of the first primary winding and the number of turns of the second primary winding to obtain the number of turns of the total primary winding;

[0078] wherein, the number of turns of the total primary winding is the sum of the number of turns of the first primary winding and the number of turns of the second primary winding.

[0079] S802, determining a first function relationship between the first displacement current and the first structural capacitance, the number of turns of the total primary winding, the number of turns of the second primary winding, and the number of turns of the secondary winding;

[0080] wherein, the first function relationship is:

[0081] ,​​

[0082] wherein, is the first displacement current, is the magnetic core skeleton height, is the first structure capacitance, is the total primary winding number of turns, is the second primary winding number of turns, is the secondary winding number of turns, is the voltage amplitude generated by the primary moving point when the switch changes, is the winding potential change time, is the secondary winding height; the above function relationship represents that, when the winding height is , the voltage corresponding to the winding height is integrated, and then multiplied by , the average value of the first displacement current can be obtained, and the corresponding voltage amplitude is multiplied by to obtain the potential corresponding to the winding height , which is in the range of

[0083] S803, determining a second function relationship between the second displacement current and the second structure capacitance, the total primary winding number of turns, the balanced winding number of turns and the secondary winding number of turns;

[0084] wherein, the second function relationship is:

[0085] ,

[0086] wherein, is the second displacement current, is the magnetic core skeleton height, is the second structure capacitance, is the total primary winding number of turns, is the balanced winding number of turns, is the secondary winding number of turns, is the voltage amplitude generated by the primary moving point when the switch changes, is the winding potential change time, is the secondary winding height.

[0087] S804, determining a corresponding relationship between the total displacement current of the transformer and the first function relationship and the second function relationship;

[0088] wherein, the corresponding relationship is:

[0089] ,

[0090] wherein,​​ is the total displacement current of the transformer, is the first displacement current, is the second displacement current.

[0091] S805, according to the first function relationship, the second function relationship and the corresponding relationship, the total displacement current of the transformer is set to zero, and the number of turns of the balance winding is obtained.

[0092] Wherein, the total displacement current of the transformer is set to zero, that is, Because the balance winding , the secondary winding and the second primary winding are tightly wound and occupy the whole transformer window space, so the interlayer medium of the winding can be approximately considered to be equal, that is, the insulating tape and the winding paint, that is, Combined with the above first function relationship and second function relationship, the calculation expression of the number of turns of the balance winding is obtained as follows:

[0093] .

[0094] Because the winding of the transformer is wound by multiple turns of wire, different layers are generated during winding, and when there is insulating medium between adjacent layers, structural capacitance is formed. As shown in Figure 2 When the electric field between the transformer windings changes, displacement current will be generated, and because the structural capacitance plays a key role in the process of electric field change, the size and distribution of the structural capacitance will directly affect the size and distribution of the displacement current. As shown in Figure 1 and Figure 2 Because displacement current is generated between adjacent windings, common-mode displacement current is generated between the auxiliary winding and the secondary winding , and between the first primary winding and the secondary winding , but because the auxiliary winding and the secondary winding , and the first primary winding and the secondary winding are connected to the primary power, the displacement common-mode current between them will flow back in the primary power loop, and will not be displaced to the secondary side to generate common-mode noise;

[0095] Because of the shielding effect of the balance winding , only the second primary winding and the secondary winding , and the balance winding and the secondary winding will generate common-mode displacement current;

[0096] Therefore, as Figure 2 shown, the total displacement current of the transformer is only the first displacement current and the second displacement current, and the current directions of the two are opposite, the first displacement current is the displacement current between the second primary winding and the secondary winding , and the second displacement current is the displacement current between the balance winding and the secondary winding .

[0097] The displacement current between the windings is induced by the pulsating voltage on the structural capacitance between the windings. By dividing the adjacent windings into small segments, each segment has a length of , and the structural capacitance corresponding to each segment is , the displacement current induced by the structural capacitance element between the adjacent windings can be calculated, and this process is realized by integration,

[0098] ,

[0099] wherein, is the displacement current, is the voltage amplitude generated by the moving point of the primary side of the corresponding segment when the switch changes, is the time corresponding to the segment, is the structural capacitance corresponding to the segment.

[0100] As Figure 6 shown, the abscissa refers to the voltage corresponding to each winding at different winding heights, and the ordinate refers to different winding heights. By integrating the abscissa and ordinate of Figure 6 , the first function relationship and the second function relationship can be obtained.

[0101] In this embodiment, the number of turns of the balance winding is calculated, so that the calculation result is more accurate, the error and uncertainty in the design process can be reduced, the electromagnetic compatibility of the transformer can be improved, the electromagnetic interference of the transformer can be reduced, and the service life and safety of the transformer can be improved; by adjusting the number of turns of the balance winding, the manufacturing process of the transformer is simplified, and different use requirements are met.

[0102] In an embodiment, a transformer is provided, as Figure 1 shown, the transformer comprises a first primary winding , a balance winding , a secondary winding , a second primary winding laid from inside to outside, one end of the balance winding is connected to one end of the second primary winding , and the second primary winding The other end of the first primary winding connected, the balance winding It is obtained by adopting the above-mentioned balanced winding design method.

[0103] Among them, the balance winding One end is connected to one end of the second primary winding, that is, terminal 2 of the transformer, and the other end is left hanging. The windings are wound in an interlaced manner.

[0104] In this embodiment, a balancing winding is provided in the transformer to balance the displacement current of the primary and secondary sides of the transformer and shield the electric field coupling between the primary and secondary sides. At the same time, interleaved winding is adopted between the windings to reduce the leakage inductance of the transformer, reduce power loss and conduction noise. Compared with the traditional setting of a single layer of shielding copper foil and an additional reverse winding, the volume of the transformer can be reduced and the production cost can be reduced.

[0105] In one embodiment, the transformer further includes an insulating tape 7 arranged between each layer of windings, the second primary winding and the secondary winding both fully wind the longitudinal window space of the transformer, and the winding height of the balance winding is equal to the winding height of the second primary winding and the secondary winding.

[0106] The insulating tape 7 provided between each layer of windings is a double-layer insulating tape.

[0107] In this embodiment, double layers of insulating tape are used between the windings of the transformer to enhance the insulation strength between the windings, isolate the windings, and ensure that each winding operates independently without interfering with each other. This also reduces current loss, lowers losses, and improves transformer efficiency. The second primary winding, secondary winding, and balance winding are arranged at equal winding heights, and all wind around the transformer's longitudinal window space, resulting in tighter coupling between the winding layers. This reduces leakage inductance, improves transformer efficiency, and reduces transformer temperature rise and noise, thereby improving transformer operational stability. A fully wound transformer can also reduce the size and weight of the transformer, lowering manufacturing costs and facilitating installation and maintenance.

[0108] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A method of designing a balanced winding of a transformer, characterized by, The transformer comprises a first primary winding, a balance winding, a secondary winding and a second primary winding which are sequentially laid from inside to outside, one end of the balance winding is connected with one end of the second primary winding, and the other end of the second primary winding is connected with the first primary winding; The balance winding design method comprises: obtaining a first structural capacitance between the second primary winding and the secondary winding, a second structural capacitance between the balance winding and the secondary winding, a number of turns of the second primary winding and a number of turns of the secondary winding; calculating the number of turns of the balance winding according to the first structural capacitance, the second structural capacitance, the number of turns of the second primary winding and the number of turns of the secondary winding; The calculation expression of the calculated first structural capacitance is: ， wherein, is the number of turns of the balancing winding, is the first structural capacitance, is the second structural capacitance, is the number of turns of the second primary winding, is the number of turns of the secondary winding; obtaining the second structural capacitance comprises: obtaining a coil radius of the balance winding, a height of the secondary winding and a second interlayer distance between the balance winding and the secondary winding; calculating the second structural capacitance according to the coil radius of the balance winding, the height of the secondary winding and the second interlayer distance between the balance winding and the secondary winding. The calculation expression of the calculated second structural capacitance is: obtaining the second structural capacitance comprises: obtaining a coil radius of the balance winding, a height of the secondary winding and a second interlayer distance between the balance winding and the secondary winding; 2. The balanced winding design method of claim 1, wherein, calculating the second structural capacitance according to the coil radius of the balance winding, the height of the secondary winding and the second interlayer distance between the balance winding and the secondary winding.

3. The balanced winding design method of claim 1, wherein, The calculation expression of the calculated second structural capacitance is: ​ ​ 4. The method of designing a balanced winding as claimed in claim 3, wherein, ​ ， wherein, is the first structure capacitance, is the vacuum permittivity, is the equivalent permittivity of the interlayer insulation material of the second primary winding and the secondary winding, is the coil radius of the secondary winding, is the height of the secondary winding, is the first interlayer distance.

5. The balanced winding design method of claim 1, wherein, ​ ​ ​ 6. The method of designing a balanced winding as claimed in claim 5, wherein, ​ ， wherein, is the second structure capacitance, is the vacuum permittivity, is the equivalent permittivity of the interlayer insulation material of the balance winding and the secondary winding, is the coil radius of the balance winding, is the height of the secondary winding, is the second interlayer distance.

7. A transformer, characterized by The transformer comprises a first primary winding, a balance winding, a secondary winding and a second primary winding which are sequentially laid from inside to outside, one end of the balance winding is connected with one end of the second primary winding, the other end of the second primary winding is connected with the first primary winding, the balance winding is obtained by using the balance winding design method in any one of claims 1-6, and the transformer further comprises an insulating tape arranged between each layer of winding.

8. A transformer according to claim 7, characterised in that The first primary winding, the second primary winding and the secondary winding all wind around the longitudinal window space of the transformer, and the height of the balance winding is equal to the height of the first primary winding, the second primary winding and the secondary winding.

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