Power main transformer structure

Abstract

The utility model provides a power main transformer structure which comprises a magnetic core, a first framework, a second framework, a primary winding and a secondary winding. The magnetic core comprises a magnetic column, the first framework and the second framework are arranged on the magnetic column in a sleeving mode, and the first framework is arranged on the outer side of the second framework in a sleeving mode. One of the primary winding and the secondary winding is wound on the first framework, and the other one is wound on the second framework. A gap is formed between the first skeleton and the second skeleton. According to the invention, the first skeleton and the second skeleton sleeve the magnetic column and are arranged in an overlapped manner, so that it can be ensured that the transmission energy of unit turns is higher than that of non-overlapped arrangement, and meanwhile, the magnetic flux leakage is small, the precision is high, and the structure is suitable for various power levels. The first framework and the second framework are spaced, so that stray capacitance between the primary winding and the secondary winding is smaller, meanwhile, the gap is used for heat dissipation and ventilation, and the loss problem and the power density problem caused by heat dissipation can be effectively reduced.

Description

Technical Field

[0001] This utility model belongs to the field of transformer equipment technology, and in particular relates to a power main transformer structure. Background Technology

[0002] A power transformer typically consists of a primary winding, a secondary winding, and a magnetic core. Essentially, it is a transformer. During the design process, various issues such as insulation, heat dissipation, and parasitic capacitance need to be considered.

[0003] In most existing power transformer structures, the primary and secondary windings are stacked using insulating media to minimize leakage flux and improve energy transmission. However, this method is difficult to dissipate heat, results in higher winding losses, and has large parasitic capacitance. If the primary and secondary windings are not stacked together, parasitic capacitance and winding losses can be reduced, and heat dissipation can also be decreased. However, this leads to poor coupling coefficients, larger secondary leakage copper, and lower energy transmission per unit number of turns, thus limiting power output. Utility Model Content

[0004] The technical objective of this invention is to provide a power main transformer structure that improves the heat dissipation capacity of the power main transformer structure without amplifying other negative effects.

[0005] To solve the above-mentioned technical problems, this utility model is implemented as follows: a power main transformer structure, comprising: a magnetic core, a first frame, a second frame, a primary winding, and a secondary winding;

[0006] The magnetic core includes a magnetic column, a first frame and a second frame are sleeved on the magnetic column, and the first frame is sleeved on the outside of the second frame;

[0007] One of the primary winding and the secondary winding is wound on the first frame, and the other is wound on the second frame;

[0008] The first and second skeletons are spaced apart.

[0009] In one embodiment, the magnetic column is provided with limiting ends at both ends, and the first frame and the second frame are both limited and matched with the limiting ends.

[0010] In one embodiment, the first frame is provided with a plurality of first limiting members at both ends, the plurality of first limiting members surround a first accommodating space, and along the first direction, the limiting end is located in the accommodating space and fits the first limiting member;

[0011] The second frame has multiple second limiting members at both ends, and the multiple second limiting members surround a second accommodating space. Along the first direction, the limiting end is located in the accommodating space and fits the second limiting member; wherein, the first direction is perpendicular to the length extension direction of the magnetic column.

[0012] In one embodiment, the magnetic column is provided with at least one groove that extends along the length of the magnetic column and penetrates the magnetic column. The second frame fits against the outer peripheral surface of the magnetic column to form a heat dissipation channel with the sidewall of the groove.

[0013] In one embodiment, the second frame includes a bonding surface and a heat dissipation surface, which are connected end to end. The heat dissipation surface and the sidewall of the groove form a heat dissipation channel, and the heat dissipation surface is hollowed out.

[0014] In one embodiment, the magnetic column is provided with limiting ends at both ends. The outer peripheral surface of the limiting end includes a limiting surface. The limiting surface and the sidewall of the groove are coplanar. The first limiting member extends along the outer peripheral surface of the end face of the first frame, and the two ends of the first limiting member are bent to form a first limiting piece. The bending angle of the first limiting piece is the same as the angle of the limiting surface.

[0015] The second limiting member extends along the outer peripheral surface of the end face of the second frame, and the two ends of the second limiting member are bent to form a second limiting piece, the bending angle of the second limiting piece being the same as the angle of the limiting surface.

[0016] In one embodiment, the magnetic core further includes side posts, one end of which is fixedly connected to the limiting end. The side posts extend in the same direction as the length of the magnetic core and are spaced apart from each other in the radial direction of the magnetic core. The first frame and the second frame are located in the receiving cavity.

[0017] In one embodiment, one end of the second frame is provided with a connector, which is fixedly connected to the second frame and extends out of the first frame, and the connector is detachably connected to the first frame.

[0018] In one embodiment, the first skeleton is hollowed out.

[0019] In one embodiment, the inner wall of the first frame is provided with inwardly protruding reinforcing ribs extending along the length direction of the first frame, spaced at a minimum distance, and the length of the reinforcing ribs is greater than the minimum distance along the radial direction of the first frame.

[0020] Compared with existing technologies, the advantages of this utility model's medium-power main transformer structure are as follows: the first and second frames are sleeved on the magnetic pillars and overlapped, which ensures higher energy transmission per unit number of turns compared to non-overlapping configurations. Simultaneously, leakage flux is smaller, accuracy is higher, and it is suitable for various power levels. The gap between the first and second frames reduces the parasitic capacitance between the primary and secondary windings, and the gap also serves for heat dissipation and ventilation, effectively reducing losses and power density issues caused by heat dissipation. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the main power transformer;

[0022] Figure 2 These are structural diagrams of the first and second skeletons;

[0023] Figure 3 This is a top view of the main power transformer structure;

[0024] Figure 4 This is a schematic diagram of the magnetic core.

[0025] In the accompanying drawings, the reference numerals represent: magnetic core 100; magnetic column 110; curved segment 111; straight segment 112; limiting end 120; limiting surface 121; heat dissipation duct 130; side post 140; first frame 200; first limiting member 210; first limiting piece 211; reinforcing rib 220; second frame 300; second limiting member 310; second limiting piece 311; connector 320; primary winding 400; secondary winding 500. Detailed Implementation

[0026] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

[0027] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "circumferential", "radial", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, "plurality" means two or more, unless otherwise specifically defined.

[0029] See Figure 1 and Figure 2 , Figure 1 A structural schematic diagram of the main power transformer is shown. Figure 2 A schematic diagram of the structure of the first frame 200 and the second frame 300 is shown. In one embodiment, this application provides a power transformer structure, mainly including a magnetic core 100, a first frame 200, a second frame 300, a primary winding 400, and a secondary winding 500. The magnetic core 100 includes a magnetic post 110, and the first frame 200 and the second frame 300 are sleeved on the magnetic post 110, with the first frame 200 sleeved outside the second frame 300. One of the primary winding 400 and the secondary winding 500 is wound on the first frame 200, and the other is wound on the second frame 300. The first frame 200 and the second frame 300 are spaced apart.

[0030] Compared with existing technologies, the advantages of this utility model's medium-power main transformer structure are as follows: The first frame 200 and the second frame 300 are sleeved on the magnetic column 110 and overlapped, which ensures higher energy transmission per unit number of turns compared to non-overlapping configurations. Simultaneously, leakage flux is smaller, accuracy is higher, and it is suitable for various power levels. The gap between the first frame 200 and the second frame 300 results in smaller parasitic capacitance between the primary winding 400 and the secondary winding 500, larger common-mode path impedance between the primary and secondary sides, and better EMI performance. Furthermore, the gap forms a flux leakage channel, creating parasitic inductance and effectively reducing the need for an external resonant inductor. Simultaneously, the gap serves for heat dissipation and ventilation, effectively reducing losses and power density issues caused by heat dissipation.

[0031] In the power transformer structure provided in this application, the spacing between the first frame 200 and the second frame 300 is determined by a combination of parasitic capacitance requirements, leakage inductance requirements, and withstand voltage capabilities. Based on capacitance requirements, it can be determined using the following formula:

[0032]

[0033] Where, d 空1 ε is the distance between the primary winding 400 and the secondary winding 500. 空 ε is the dielectric constant of air. 补 denoted as the dielectric constant of the insulating medium, Sps is the overlap distance between the primary winding 400 and the secondary winding 500, and Cps is the parasitic equivalent capacitance between the primary winding 400 and the secondary winding 500.

[0034] Based on the leakage sensing requirements, the interval distance formula is as follows:

[0035]

[0036] Where, d 空2 The air distance between the primary winding (400) and the secondary winding (500) is L. kFor parasitic leakage inductance, h is the transformer window height, μ0 is the air permeability, and N is the number of transformer turns.

[0037] From the perspective of insulation withstand voltage, the formula for the spacing is as follows:

[0038] d 空3

[0039] Where, d 空3 U is the air gap between the primary winding 400 and the secondary winding 500, U is the voltage across the air gap, and E is the maximum allowable electric field strength in the air.

[0040] In this design, the dimensions of the second frame 300 are controlled by the dimensions of the magnetic post 110. The difference between the equivalent inner diameter d1 of the first frame 200 and the outer diameter d2 of the smaller frame is equal to the air distance between the primary winding 400 and the secondary winding 500, plus the thickness D of the winding wound on the second frame 300. The formula is as follows:

[0041] d2 = d1 + D + d 空

[0042] Where d 空 The value is d 空1 d 空2 d 空3 One of them, is actually defined according to requirements.

[0043] The structure of the magnetic core 100, the frame structure, and the actual design parameters are collectively determined by these three factors. The magnetic core 100 is used to fix the first frame 200 and the second frame 300. The first frame 200 and the second frame 300 together provide a heat dissipation cavity for the magnetic core 100 and the windings, and are coupled to each other, thus solving both fixing and heat dissipation functions. This allows for flexible adjustment of the parasitic parameters and heat dissipation capacity of the entire magnetic device according to actual design requirements.

[0044] In this solution, the magnetic core 100, primary winding 400, and secondary winding 500 can be wound separately on different frames. Since they are all detachably connected, they can be processed separately. From a manufacturing perspective, this facilitates assembly line processing, increases processing speed, and also improves the insulation performance of the primary winding 400 and secondary winding 500, which is beneficial to the reliability of the magnetic device. This allows for the use of automated equipment to process the windings. Furthermore, by winding the primary winding 400 and secondary winding 500 separately, the distance between them can be selected based on the parasitic capacitance, parasitic inductance, and insulation withstand voltage requirements of the actual design. This allows for customization of parasitic inductance and capacitance, meeting high withstand voltage requirements while also addressing the heat dissipation issues of the primary winding 400 and secondary winding 500. This solution enables magnetic devices to achieve higher power density, higher reliability, higher processing speed, higher withstand voltage requirements, and better EMI performance, while also integrating partial resonant inductance functionality as needed.

[0045] In this application, the first frame 200 and the second frame 300 are cylindrical. The diameter of the first frame 200 is larger than that of the second frame 300, so the first frame 200 can be fitted over the second frame 300. Either the first frame 200 or the second frame 300 can serve as the primary frame, and the other as the secondary frame. In the attached diagram, the primary winding 400 is wound around the first frame, and the secondary winding 400 is wound around the second frame 300. The number of turns of the primary winding 400 and the secondary winding 500 can be determined according to specific requirements. The stability of the spacing between the first frame 200 and the second frame 300 only requires a fixed connection between them, which can be direct or indirect. This application uses an indirect connection method.

[0046] For details, please refer to Figure 1 In one embodiment, the present application uses a magnetic core 100 to fix the first frame 200 and the second frame 300, thereby ensuring the stability of the gap between them. In one embodiment, the magnetic post 110 has limiting ends 120 at both ends, and the first frame 200 and the second frame 300 are both limited and engaged with the limiting ends 120. Specifically, the first frame 200 has multiple first limiting members 210 at both ends, which enclose a first receiving space. Along a first direction, the limiting ends 120 are located in the receiving space and abut against the first limiting members 210. The second frame 300 has multiple second limiting members 310 at both ends, which enclose a second receiving space. Along a first direction, the limiting ends 120 are located in the receiving space and abut against the second limiting members 310; wherein, the first direction is perpendicular to the length extension direction of the magnetic post 110.

[0047] from Figure 1As can be seen, the first limiting member 210 of the first frame 200 and the second limiting member 310 of the second frame 300 clamp the limiting end 120 of the magnetic core 100 in the middle. Both the first frame 200 and the second frame 300 are restricted in space movement and rotation by the limiting end 120, so that the two are relatively fixedly connected. This ensures the stability of the interval.

[0048] The magnetic device assembly sequence in this application is as follows: the primary winding 400 and the secondary winding 500 are wound on the corresponding first bobbin 200 and second bobbin 300, respectively. The primary winding 400 and the secondary winding 500 can be operated separately. Then, the second bobbin 300 winding is first assembled onto the magnetic post 110, and then the first bobbin 200 is assembled onto the magnetic post 110. It is fixed onto the magnetic post 110 by the first limiting member 210 and the second limiting member 310 to ensure that the relative position of the first bobbin 200 and the second bobbin 300 is the designed position.

[0049] In some other embodiments, the first frame 200 and the second frame 300 can also be directly fixedly connected, see reference. Figure 2 One end of the second frame 300 is provided with a connector 320. The connector 320 is fixedly connected to the second frame 300 and extends out to the first frame 200. The connector 320 is detachably connected to the first frame 200. When the second frame 300 does not have a second limiting member 310, connectors 320 can be provided at both ends of the second frame 300 to fix the second frame 300 and the first frame 200. The first connector 320 of the first frame 200 is used to achieve a fixed connection with the magnetic core 100.

[0050] See Figure 3 and Figure 4 , Figure 3 A top view of the main power transformer structure is shown. Figure 4 A structural diagram of the magnetic column 110 is shown. In one embodiment, the magnetic column 100 has at least one groove. In this embodiment, two grooves are provided, and the two grooves are symmetrical along a half-section of the magnetic column 110. Specifically, the outer peripheral surface of the magnetic column 110 includes a curved segment 111 and a straight segment 112. The second frame 300 fits into the curved segment 111, and the straight segment 112 is inclined towards the center of the magnetic column 110. The two straight segments 112 form grooves on the side of the magnetic column 110. The first frame 200 and the grooves form a heat dissipation channel 130, improving the heat dissipation capacity of the entire power transformer structure. In this embodiment, the magnetic column 110 is a cylinder with two fan-shaped notches formed on symmetrical sides. The straight segments 112 are the two radii of the fan-shaped notches. However, these radii are not the radii of the magnetic column 110 itself, because the apex of the fan-shaped notch cannot be the axis of the magnetic column 110.

[0051] In other embodiments, the magnetic post 110 can be in other shapes, such as rectangular or other polygonal prisms. The groove does not have to be fan-shaped. As long as the relative position of the first frame 200 and the magnetic post 110 and the magnetic strength of the magnetic post 110 are not affected, it is sufficient to form a cavity between the first frame 200 and the magnetic post 110 that connects to the external environment on both sides to facilitate heat dissipation.

[0052] Preferred options, please refer to Figure 2 , combined with Figure 4 In one embodiment, due to the presence of the groove, the side of the second frame 300 is naturally divided into a contact surface and a heat dissipation surface. The contact surface is in contact with the magnetic post 110, while the heat dissipation surface and the side wall of the groove form a heat dissipation duct 130. In this embodiment, the openwork on the heat dissipation surface facilitates faster heat dissipation from the primary winding 400 or secondary winding 500 wound on the first frame 200. Similarly, since there is a gap between the first frame 200 and the second frame 300, the second frame 300 can also be openwork. Unlike the first frame 200, which only has an openwork on its heat dissipation surface, the second frame 300, due to the 360° gap between it and the first frame 200 on its outer circumference, can be completely openwork to facilitate smoother heat transfer and improve heat dissipation.

[0053] See Figure 1 and Figure 4 In one embodiment, the outer peripheral surface of the limiting end 120 includes a limiting surface 121. The straight segment 112 of the outer peripheral surface of the magnetic post 110 is coplanar with the limiting surface 121, and both the first limiting member 210 and the second limiting member 310 are in contact with the limiting surface 121. This coplanar arrangement prevents obstruction of both ends of the heat dissipation duct 130, thus facilitating heat dissipation. Furthermore, since the outer peripheral surface of the limiting end 120 is planar, the first limiting member 210 of the first frame 200 and the second limiting member 310 of the second frame 300 are more easily in contact with the limiting surface 121.

[0054] In the above embodiment, the groove cross-section is a fan-shaped surface, making the side of the limiting end 120 resemble an "X" shape. When the groove cross-section is a different shape, the limiting surface 121 of the limiting end 120 can be adjusted accordingly, so that the heat dissipation air duct can pass through the magnetic column 110 and the limiting end 120. This not only facilitates heat dissipation, but also ensures that the diameter of the first frame 200 and the second frame 300 is greater than the minimum distance between the sides of the limiting end 120, so that the first limiting member 210 and the second limiting member 310 can be locked on both sides of the limiting end 120, stabilizing the relative position of the first frame 200 and the second frame 300.

[0055] Preferably, in one embodiment, the first limiting member 210 and the second limiting member 310 have the same structure, see reference. Figure 2The first limiting member 210 extends along the outer peripheral surface of the end face of the first frame 200, and both ends of the first limiting member 210 are bent to form a first limiting piece 211. The bending angle of the first limiting piece 211 is the same as the angle of the limiting surface 121. The second limiting member 310 extends along the outer peripheral surface of the end face of the second frame 300, and both ends of the second limiting member 310 are bent to form a second limiting piece 311. The bending angle of the second limiting piece 311 is the same as the angle of the limiting surface 121. When the limiting surface 121 is a straight line, the first limiting piece 211 and the second limiting piece 311 are also straight lines. When the limiting surface 121 is a curve, the first limiting member 210 and the second limiting member 310 are also curved to better fix the positions of the first frame 200 and the second frame 300.

[0056] from Figure 2 As can be seen, since the diameter of the first skeleton 200 is larger than that of the second skeleton 300, the first limiting piece 211 is biased to the outside of the limiting surface 121 compared to the second limiting piece 311, and the circumference of the first limiting piece 210 is longer than that of the second limiting piece 310.

[0057] See Figure 4 In one embodiment, the magnetic core 100 further includes side posts 140. Specifically, the limiting end 120 has four sides, two of which are opposite sides serving as limiting surfaces 121, and the ends of the other two surfaces are used for fixed connection of the side posts 140. The side posts 140 and magnetic posts 110 are arranged at intervals, and the limiting end 120 and magnetic posts 110 enclose a receiving cavity, in which the first frame 200 and the second frame 300 are located. The side posts 140 mainly serve to protect the second frame 300 and the windings wound on the second frame 300.

[0058] Preferably, in other embodiments, side posts 140 can be provided around the limiting end 120 to improve the protection effect. In this case, multiple through holes are provided on the limiting end 120 to connect to the heat dissipation duct 130, and the sidewalls of the through holes are used to fix the first frame 200 and the second frame 300. However, compared with the above embodiment where only the two ends are provided with side posts 140, the heat dissipation capacity will be slightly insufficient.

[0059] See Figure 2In one embodiment, the inner wall of the first frame 200 is provided with inwardly protruding reinforcing ribs 220 extending along the length of the first frame 200. The reinforcing ribs 220 firstly increase the structural strength of the first frame 200, and secondly, they can be used to determine the minimum spacing, which varies depending on the specific requirements of the power transformer structure and the different material parameters. Generally, it refers to the air breakdown thickness corresponding to the minimum common-mode voltage between the primary winding 400 and the secondary winding 500. Preferably, multiple reinforcing ribs 220 are provided and evenly distributed circumferentially on the inner wall of the first frame 200, for example, six reinforcing ribs 220, with an angle of 60° between adjacent reinforcing ribs 220.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A power main transformer structure, characterized in that, include: Magnetic core (100), first frame (200), second frame (300), primary winding (400) and secondary winding (500); The magnetic core (100) includes a magnetic post (110), the first skeleton (200) and the second skeleton (300) are sleeved on the magnetic post (110), and the first skeleton (200) is sleeved on the outside of the second skeleton (300); One of the primary winding (400) and the secondary winding (500) is wound on the first frame (200), and the other is wound on the second frame (300); The first skeleton (200) and the second skeleton (300) are spaced apart.

2. The power transformer structure according to claim 1, characterized in that, The magnetic column (110) is provided with limiting ends (120) at both ends, and the first frame (200) and the second frame (300) are both limited and matched with the limiting ends (120).

3. The power transformer structure according to claim 2, characterized in that, The first frame (200) has multiple first limiting members (210) at both ends, and the multiple first limiting members (210) surround a first accommodating space. Along the first direction, the limiting end (120) is located in the accommodating space and fits the first limiting member (210). The second skeleton (300) has multiple second limiting members (310) at both ends, and the multiple second limiting members (310) surround a second accommodating space. Along the first direction, the limiting end (120) is located in the accommodating space and fits the second limiting member (310); wherein, the first direction is perpendicular to the length extension direction of the magnetic column (110).

4. The power transformer structure according to claim 3, characterized in that, The magnetic column (110) is provided with at least one groove, which extends along the length of the magnetic column (110) and penetrates the magnetic column (110). The second skeleton (300) fits against the outer peripheral surface of the magnetic column (110) to form a heat dissipation duct (130) with the side wall of the groove.

5. The power transformer structure according to claim 4, characterized in that, The second frame (300) includes a bonding surface and a heat dissipation surface, the bonding surface and the heat dissipation surface are connected end to end, the heat dissipation surface and the side wall of the groove form a heat dissipation air duct (130), and the heat dissipation surface is hollowed out.

6. The power transformer structure according to claim 4, characterized in that, The outer peripheral surface of the limiting end (120) includes a limiting surface (121), the limiting surface (121) and the side wall of the groove are coplanar, the first limiting member (210) extends along the outer peripheral surface of the end face of the first skeleton (200), and the two ends of the first limiting member (210) are bent to form a first limiting piece (211), the bending angle of the first limiting piece (211) is the same as the angle of the limiting surface (121); The second limiting member (310) extends along the outer peripheral surface of the end face of the second skeleton (300), and the two ends of the second limiting member (310) are bent to form a second limiting piece (311), and the bending angle of the second limiting piece (311) is the same as the angle of the limiting surface (121).

7. The power transformer structure according to any one of claims 2-6, characterized in that, The magnetic core (100) also includes a side post (140), one end of which is fixedly connected to the limiting end (120). The extension direction of the side post (140) is the same as the length direction of the magnetic column (110), and the side post (140) and the magnetic column (110) are arranged at intervals in the radial direction of the magnetic column (110). The first skeleton (200) and the second skeleton (300) are located in the receiving cavity.

8. The power transformer structure according to any one of claims 1-6, characterized in that, One end of the second frame (300) is provided with a connector (320), the connector (320) is fixedly connected to the second frame (300) and extends out to the first frame (200), and the connector (320) is detachably connected to the first frame (200).

9. The power transformer structure according to any one of claims 1-6, characterized in that, The first skeleton (200) is hollowed out.

10. The power transformer structure according to any one of claims 1-6, characterized in that, The inner wall of the first skeleton (200) is provided with an inwardly protruding reinforcing rib (220) extending along the length direction of the first skeleton (200), the interval having a minimum distance, and the length of the reinforcing rib (220) is greater than the minimum distance along the radial direction of the first skeleton (200).

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