Transformer and Variable Frequency Microwave Oven Power Supply Structure

Abstract

This application discloses a transformer and a power supply structure for a variable frequency microwave oven. The transformer includes a frame and a magnetic core assembly. The frame has a central hole; the magnetic core assembly is supported by the frame and includes a central magnetic post that passes through the central hole; the saturation magnetic flux density of the magnetic core assembly is greater than 420 millitalas; the diameter of the central magnetic post ranges from 13.5 mm to 15.5 mm; the difference between the diameter of the central hole and the diameter of the central magnetic post ranges from 1 mm to 5 mm. These features enable the miniaturization of the transformer.

Description

Technical Field

[0001] This application relates to the technical field of power supply structure for frequency converter microwave ovens, and in particular to a transformer and power supply structure for frequency converter microwave ovens. Background Technology

[0002] The power supply structure of a frequency converter microwave oven typically includes a transformer. In related technologies, a power supply structure for a frequency converter microwave oven has been proposed. However, in these technologies, the transformer has a large size, which leads to a relatively large size of the power supply structure for the frequency converter microwave oven. Utility Model Content

[0003] The main technical problem addressed by this application is to provide a transformer and a power supply structure for a frequency converter microwave oven, which enables the transformer to be miniaturized.

[0004] To address the aforementioned problems, this application provides a transformer comprising a frame and a core assembly. The frame has a central hole; the core assembly is supported by the frame and includes a central magnetic post that passes through the central hole; the core assembly has a saturation magnetic flux density greater than 420 millitalas; the diameter of the central magnetic post ranges from 13.5 mm to 15.5 mm; and the difference between the diameter of the central hole and the diameter of the central magnetic post ranges from 1 mm to 5 mm.

[0005] As mentioned above, the saturation magnetic flux density of the magnetic core assembly is greater than 420 millitalas. This increases the saturation magnetic flux density of the magnetic core assembly, which allows for a reduction in the diameter of the central magnetic column and a smaller size of the central magnetic column. Consequently, the volume of the frame can also be reduced, enabling the transformer to be miniaturized.

[0006] In one possible implementation, the magnetic core assembly includes a first magnetic core and a second magnetic core, the first magnetic core and the second magnetic core being U-shaped magnetic cores; the open ends of the first magnetic core and the second magnetic core are aligned to form a closed magnetic circuit; wherein, the central magnetic pillar includes a first central pillar located on the first magnetic core and a second central pillar located on the second magnetic core, with a first air gap between the first central pillar and the second central pillar; the magnetic core assembly also includes side magnetic pillars, the side magnetic pillars including a first side pillar located on the first magnetic core and a second side pillar located on the second magnetic core, with a second air gap between the first side pillar and the second side pillar.

[0007] As described above, the first magnetic core and the second magnetic core can form a magnetic circuit when closed, and the first air gap and the second air gap are used to adjust the magnetic circuit saturation and leakage inductance of the magnetic core assembly.

[0008] In one possible implementation, a first protrusion structure is formed within the wall of the central hole, the first protrusion structure being located between the first central post and the second central post to form the first air gap; specifically, the size of the first protrusion structure along the axial direction of the central hole ranges from 1.2 mm to 2.5 mm.

[0009] As described above, the first protrusion structure enables the formation of a first air gap between the first central column and the second central column.

[0010] In one possible implementation, there are multiple first protrusion structures, which are circumferentially spaced on the hole wall.

[0011] The distribution of the first protrusion structure can be varied.

[0012] In one possible implementation, the circumferential cross-sectional area of ​​the edge magnetic post is 40% to 70% of the circumferential cross-sectional area of ​​the middle magnetic post.

[0013] As mentioned above, the saturation magnetic flux density of the edge magnetic column is less than that of the middle magnetic column, and the diameter of the edge magnetic column is less than that of the middle magnetic column. Similarly, the diameter of the edge magnetic column can also be reduced accordingly.

[0014] In one possible implementation, the frame has a high-voltage winding portion, which includes a first annular groove and a second annular groove, the first annular groove and the second annular groove being axially spaced apart on the outer wall of the frame; the high-voltage winding portion also forms a wire-holding groove; the frame also has a low-voltage winding portion, which includes a third annular groove; along the axial direction of the central hole, the high-voltage winding portion and the low-voltage winding portion are located on both sides of the first protrusion structure.

[0015] As mentioned above, the high-voltage winding section has a two-slot structure, which results in lower voltage stress per slot and higher reliability compared to a single-slot structure.

[0016] In one possible implementation, the transformer further includes: a high-voltage winding wound in the first annular groove and the second annular groove; a low-voltage winding wound in the third annular groove; the high-voltage winding has fewer than 272 turns; and the low-voltage winding has fewer than 34 turns.

[0017] As mentioned above, the high-voltage winding is wound inside the first and second annular grooves, which reduces the voltage stress in each groove.

[0018] In one possible implementation, the transformer further includes a mounting box surrounding the edge magnetic post.

[0019] As mentioned above, the fixing box can protect the edge magnetic posts.

[0020] In one possible implementation, a second protrusion structure is formed inside the fixing box, the second protrusion structure being located between the first side post and the second side post to form the second air gap.

[0021] The second protrusion structure enables a second air gap to be formed between the first side post and the second side post.

[0022] To address the aforementioned issues, this application also provides a variable frequency microwave oven power supply structure, which includes the aforementioned transformer.

[0023] As mentioned above, the saturation magnetic flux density of the magnetic core component in the variable frequency microwave oven power supply structure is greater than 420 millitalas. This increases the saturation magnetic flux density of the magnetic core component, thus reducing the diameter of the central magnetic column and the size of the central magnetic column. Consequently, the volume of the frame can also be reduced, enabling the microwave oven power supply structure to be miniaturized. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the frame structure in the transformer of this application;

[0026] Figure 2 for Figure 1 A schematic diagram of the structure at the central hole in the skeleton;

[0027] Figure 3 for Figure 1 A structural diagram of the skeleton from another perspective;

[0028] Figure 4 This is a schematic diagram of the magnetic core assembly in the transformer of this application;

[0029] Figure 5 This is a schematic diagram of the fixed box in the transformer of this application.

[0030] Figure label:

[0031] 11. Skeleton; 111. First annular groove; 112. Second annular groove; 113. Third annular groove; 114. Center hole; 115. First protrusion structure; 12. Magnetic core assembly; 121. First magnetic core; 124. Second magnetic core; 122. First central post; 123. First side post; 125. Second central post; 126. Second side post; 127. Central magnetic post; 128. Side magnetic post; 13. Fixing box; 131. Second protrusion structure; 132. Concave groove. Detailed Implementation

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0033] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the application. The singular forms “a,” “said,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless otherwise clearly indicated above. “Multiple” generally includes at least two, but does not exclude the inclusion of at least one.

[0034] It should be understood that the term "and / or" used herein is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Furthermore, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship. The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0035] It should be understood that the terms "comprising," "including," or any other variations used herein are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0036] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in every place in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0037] Existing transformers are bulky, resulting in a large power supply structure for inverter microwave ovens. To address this technical problem, this application provides a transformer and an inverter microwave oven power supply structure. The transformer features a core assembly with a saturation magnetic flux density greater than 420 millitalas, and the diameter of the central magnetic column ranges from 13.5 mm to 15.5 mm, effectively solving the aforementioned technical problem.

[0038] Please see Figures 1 to 5 , Figure 1 This is a schematic diagram of the frame structure in the transformer of this application; Figure 2 for Figure 1 A schematic diagram of the structure at the central hole in the skeleton; Figure 3 for Figure 1 A structural diagram of the skeleton from another perspective; Figure 4 This is a schematic diagram of the magnetic core assembly in the transformer of this application; Figure 5 This is a schematic diagram of the fixed box in the transformer of this application.

[0039] In one specific embodiment, the transformer (not shown) includes a frame 11 and a core assembly 12. The frame 11 has a central hole 114; the core assembly 12 is supported by the frame 11, and the core assembly 12 includes a central magnetic post 127 that passes through the central hole 114; the saturation magnetic flux density of the core assembly 12 is greater than 420 millitalas; the diameter of the central magnetic post 127 ranges from 13.5 mm to 15.5 mm; the difference between the diameter of the central hole 114 and the diameter of the central magnetic post 127 ranges from 1 mm to 5 mm.

[0040] The frame 11 is used to support and fix the magnetic core assembly 12, and it is also used for winding and fixing the winding (not shown). The frame 11 can be made of plastic, ceramic, composite materials, etc. The magnetic core assembly 12, as a conductor of magnetic flux, helps guide and limit the magnetic flux, forming a closed magnetic circuit. The magnetic core assembly 12 includes a central magnetic post 127, which, together with the side magnetic posts 128, forms a closed magnetic circuit. The central magnetic post 127 passes through the central hole 114, which can fix the central magnetic post 127. In this embodiment, the saturation magnetic flux density of the magnetic core assembly 12 is greater than 420 millistas. Saturation magnetic flux density refers to the magnetic flux density when a material reaches a saturated state under the action of a magnetic field. The saturation magnetic flux density of the magnetic core assembly 12 can be a reasonable value such as 430 millistas, 440 millistas, or 450 millistas. The magnetic material used to manufacture the magnetic core assembly 12 can be manganese-zinc ferrite, soft magnetic alloy, amorphous nanocrystalline material, etc., and the saturation magnetic flux density of the magnetic core assembly 12 made of the above materials can be greater than 420 millisieverts. In related technologies, the saturation magnetic flux density of the central magnetic column 127 of the transformer is less than 420 millisieverts. Due to the relatively low saturation magnetic flux density of the central magnetic column 127, to achieve the output power range of 700W-800W for the inverter microwave oven, the diameter of the central magnetic column 127 needs to reach 16 mm. In this embodiment, by setting the magnetic core assembly 12 with a magnetic material having a saturation magnetic flux density greater than 420 millisieverts, the diameter of the central magnetic column 127 can be reduced to 13.5 mm to 15.5 mm, specifically 13.5 mm, 14 mm, 15 mm, 15.5 mm, etc. On the other hand, in this embodiment, the central magnetic post 127 passes through the central hole 114. The diameter of the central magnetic post 127 is smaller than the diameter of the central hole 114, creating a gap between the central magnetic post 127 and the hole wall of the central hole 114. This gap can be used to form an airflow path to cool the central magnetic post 127 and dissipate heat. Simultaneously, this air gap also helps increase the withstand voltage between the transformer winding and the core assembly 12. In other embodiments, the hole wall of the central hole 114 can also have a hollow structure to further improve heat dissipation. In some preferred embodiments, the difference between the diameter of the central hole 114 and the diameter of the central magnetic post 127 ranges from 1 mm to 5 mm, and specifically, the difference can be 1 mm, 1.5 mm, 2 mm, 4 mm, 5 mm, etc. Please refer to [link / reference]. Figure 2 In one specific embodiment, Figure 2 In the figure, 'a' represents the diameter of the central hole 114, which can be 15.8 mm.

[0041] As mentioned above, the saturation magnetic flux density of the magnetic core assembly 12 is greater than 420 millitalas, which increases the saturation magnetic flux density of the magnetic core assembly 12. Therefore, the diameter of the central magnetic column 127 can be reduced, the size of the central magnetic column 127 can be reduced, and the volume of the frame 11 can also be reduced accordingly, which can make the transformer smaller.

[0042] In some embodiments, the magnetic core assembly 12 includes a first magnetic core 121 and a second magnetic core 124, which are U-shaped magnetic cores; the open ends of the first magnetic core 121 and the second magnetic core 124 are aligned to form a closed magnetic circuit; wherein, the central magnetic post 127 includes a first central post 122 located in the first magnetic core 121 and a second central post 125 located in the second magnetic core 124, and a first air gap (not shown) is provided between the first central post 122 and the second central post 125; the magnetic core assembly 12 also includes a side magnetic post 128, which includes a first side post 123 located in the first magnetic core 121 and a second side post 126 located in the second magnetic core 124, and a second air gap (not shown) is provided between the first side post 123 and the second side post 126.

[0043] The first central post 122 and the first side post 123 of the first magnetic core 121 are connected by a first connecting post (not shown). The second central post 125 and the second side post 126 of the second magnetic core 124 are connected by a second connecting post (not shown). The first central post 122 and the second central post 125 are used to wind a high-voltage winding (not shown) and a low-voltage winding (not shown), respectively. The first air gap and the second air gap are used to adjust the magnetic circuit saturation and leakage inductance. The size of the first air gap and the second air gap can be the same or different, and the first air gap and the second air gap can be adjusted according to the required inductance. In this embodiment, the first central post 122 and the second central post 125 are cylindrical. The cylindrical shape of the magnetic post facilitates the winding. In other embodiments, the first central post 122 and the second central post 125 can also be rectangular or other prismatic. In this embodiment, the first side post 123 and the second side post 126 are rectangular. In other embodiments, the first side post 123 and the second side post 126 may also be cylindrical or other prismatic.

[0044] As described above, the first magnetic core 121 and the second magnetic core 124 can form a magnetic circuit when closed, and the first air gap and the second air gap are used to adjust the magnetic circuit saturation and leakage inductance of the magnetic core assembly 12.

[0045] In some embodiments, a first protrusion structure 115 is formed in the wall of the central hole 114, the first protrusion structure 115 being located between the first central post 122 and the second central post 125 to form a first air gap; specifically, the size of the first protrusion structure 115 along the axial direction of the central hole 114 ranges from 1.2 mm to 2.5 mm.

[0046] The first protruding structure 115 is used to separate the first central post 122 and the second central post 125 within the central hole 114 to form a first air gap. In this embodiment, the first protruding structure 115 and the hole wall of the central hole 114 are an integral structure. The first protruding structure 115 is made of non-magnetic materials such as plastic or ceramic. In other embodiments, the first protruding structure 115 can be an independent structure fixed within the central hole 114. The first protruding structure 115 can be made of a magnetic material with low magnetic flux density, allowing the magnetic flux between the first central post 122 and the second central post 125 to be adjusted through the first protruding structure 115. In other embodiments, the first protruding structure 115 can also be made of an adhesive material, so that the first protruding structure 115 can also serve to fix the first central post 122 and the second central post 125. In this embodiment, the first protruding structure 115 is cross-shaped. In other embodiments, the first protruding structure 115 can also be mesh-like, sheet-like, strip-like, etc., and the shape of the first protruding structure 115 is not specifically limited. In other embodiments, there may be multiple first protrusions 115, which may be circumferentially spaced on the hole wall. Specifically, the dimensions of the first protrusions 115 along the axial direction of the central hole 114 may be 1.2 mm, 1.5 mm, 1.8 mm, 2.1 mm, 2.5 mm, etc. Please refer to [link / reference]. Figure 2 In one specific embodiment, Figure 2 In the figure, 'a' represents the diameter of the central hole 114, which can be 15.8 mm. Figure 2 In the figure, b is the diameter of the central hole 114 after deducting the first protrusion structure 115. b can be 14.6 mm, that is, the size of the first protrusion structure 115 along the axial direction of the central hole 114 is 1.2 mm. c is the outer diameter of the central hole 114, which can be 20.9 mm.

[0047] As described above, the first protrusion structure 115 enables the formation of a first air gap between the first central column 122 and the second central column 125.

[0048] In some embodiments, the circumferential cross-sectional area of ​​the edge magnetic post 128 is 40% to 70% of the circumferential cross-sectional area of ​​the middle magnetic post 127.

[0049] In this embodiment, the magnetic flux of the central magnetic post 127 is greater than that of the edge magnetic post 128. This application reduces the cross-sectional area of ​​both the edge magnetic post 128 and the central magnetic post 127 by increasing the saturation magnetic flux density of the magnetic core assembly 12. Specifically, the circumferential cross-sectional area of ​​the edge magnetic post 128 can be 40%, 50%, 60%, 70%, etc., of the circumferential cross-sectional area of ​​the central magnetic post 127.

[0050] As mentioned above, the saturation magnetic flux density of the edge magnetic column 128 is less than that of the middle magnetic column 127, and the diameter of the edge magnetic column 128 is less than that of the middle magnetic column 127. Similarly, the diameter of the edge magnetic column 128 can also be reduced accordingly.

[0051] In some embodiments, the frame 11 has a high-voltage winding portion (not shown), which includes a first annular groove 111 and a second annular groove 112, which are axially spaced apart on the outer wall of the frame 11; the high-voltage winding portion also forms a wire-holding groove (not shown); the frame 11 also has a low-voltage winding portion (not shown), which includes a third annular groove 113; along the axial direction of the central hole 114, the high-voltage winding portion and the low-voltage winding portion are located on both sides of the first protrusion structure 115. The transformer also includes: a high-voltage winding wound in the first annular groove 111 and the second annular groove 112; a low-voltage winding wound in the third annular groove 113; the high-voltage winding has fewer than 272 turns; and the low-voltage winding has fewer than 34 turns.

[0052] In this embodiment, the high-voltage winding section includes a first annular groove 111 and a second annular groove 112. Both the first annular groove 111 and the second annular groove 112 are used to wind the high-voltage winding. Compared with a single-groove winding structure for the high-voltage winding, this application can reduce the voltage stress on the winding groove. In this embodiment, the high-voltage winding section is provided with one winding groove. In other embodiments, the high-voltage winding section can also be provided with three, four, or other numbers of winding grooves. In addition, in this embodiment, the low-voltage winding section is provided with one winding groove. In other embodiments, the low-voltage winding section can also be provided with two or other numbers of winding grooves. The number of turns of the high-voltage winding can specifically be 270 turns, 260 turns, 250 turns, etc. The number of turns of the low-voltage winding can specifically be 32 turns, 30 turns, 28 turns, etc.

[0053] As mentioned above, the high-voltage winding section has a two-slot structure, which results in lower voltage stress per slot and higher reliability compared to a single-slot structure.

[0054] In some embodiments, the transformer further includes a mounting box 13, which surrounds the edge magnetic post 128.

[0055] In this embodiment, the fixing box 13 is also fixed to the frame 11 by an iron core clamp. In other embodiments, the fixing box 13 can also be fixed to the frame 11 by a snap-fit ​​structure, bolts, or other means. The fixing box 13 has a concave groove 132 to cover the three sides of the edge magnetic post 128 near the coil for protection. In some preferred embodiments, a second protruding structure 131 is formed within the concave groove 132 of the fixing box 13. The second protruding structure 131 is located between the first side post 123 and the second side post 126 to form a second air gap. The second protruding structure 131 serves to separate the first side post 123 and the second side post 126 within the concave groove 132 to form the second air gap. In this embodiment, the second protruding structure 131 and the groove wall of the concave groove 132 are an integrated structure. In other embodiments, the second protruding structure 131 can be an independent structure fixed within the concave groove 132. The second protruding structure 131 can be made of a low magnetic flux density magnetic material, allowing adjustment of the magnetic flux between the first side post 123 and the second side post 126. In other embodiments, the second protruding structure 131 can also be made of an adhesive material, so that it can also serve to fix the first side post 123 and the second side post 126. The second protruding structure 131 can be mesh-like, sheet-like, strip-like, etc., and its shape is not specifically limited.

[0056] As described above, the fixing box 13 can protect the side magnetic post 128, and the second protrusion structure 131 can form a second air gap between the first side post 123 and the second side post 126.

[0057] Correspondingly, this application also provides a variable frequency microwave oven power supply structure, which includes the aforementioned transformer.

[0058] As described above, the saturation magnetic flux density of the magnetic core assembly 12 in the variable frequency microwave oven power supply structure is greater than 420 millitalas. The increased saturation magnetic flux density of the magnetic core assembly 12 allows for a reduction in the diameter of the central magnetic column 127, thus reducing the size of the central magnetic column 127. Consequently, the volume of the frame 11 can also be reduced, enabling the microwave oven power supply structure to be miniaturized.

[0059] The above are merely embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A transformer, characterized by The transformer includes: A skeleton having a central hole; A magnetic core assembly, the magnetic core assembly being supported by the skeleton, the magnetic core assembly including a central magnetic post, the central magnetic post being inserted through the central hole; The saturation magnetic flux density of the magnetic core assembly is greater than 420 millitalas; the diameter of the central magnetic post ranges from 13.5 mm to 15.5 mm; The difference between the diameter of the central hole and the diameter of the central magnetic post ranges from 1 mm to 5 mm.

2. The transformer according to claim 1, characterized in that, The magnetic core assembly includes a first magnetic core and a second magnetic core, wherein the first magnetic core and the second magnetic core are U-shaped magnetic cores; The open ends of the first magnetic core and the second magnetic core are aligned to form a closed magnetic circuit; The central magnetic column includes a first central column located in the first magnetic core and a second central column located in the second magnetic core, and a first air gap is provided between the first central column and the second central column; The magnetic core assembly further includes a side magnetic post, which includes a first side post located in the first magnetic core and a second side post located in the second magnetic core, with a second air gap between the first side post and the second side post.

3. The transformer according to claim 2, characterized in that, A first protrusion structure is formed inside the wall of the central hole, and the first protrusion structure is located between the first central column and the second central column to form the first air gap; Specifically, the dimension of the first protrusion structure along the axial direction of the central hole ranges from 1.2 mm to 2.5 mm.

4. The transformer according to claim 3, characterized in that, The number of the first protrusion structure is multiple, and the first protrusion structure is distributed circumferentially at intervals on the hole wall.

5. The transformer according to claim 2, characterized in that, The circumferential cross-sectional area of ​​the edge magnetic column is 40% to 70% of the circumferential cross-sectional area of ​​the middle magnetic column.

6. The transformer according to claim 3, characterized in that, The frame has a high-voltage winding section, which includes a first annular groove and a second annular groove, which are axially spaced apart on the outer wall of the frame; the high-voltage winding section also has a wire-locking groove. The skeleton also has a low-voltage winding section, which includes a third annular groove; Along the axial direction of the central hole, the high-voltage winding portion and the low-voltage winding portion are located on both sides of the first protrusion structure.

7. The transformer of claim 6, wherein, The transformer also includes: A high-voltage winding, wherein the high-voltage winding is wound in the first annular groove and the second annular groove; A low-voltage winding, wherein the low-voltage winding is wound within the third annular groove; The high-voltage winding has fewer than 272 turns; the low-voltage winding has fewer than 34 turns.

8. The transformer of claim 2, wherein, The transformer also includes: A fixing box, which surrounds the edge magnetic post.

9. The transformer according to claim 8, characterized in that, A second protrusion structure is formed inside the fixing box, and the second protrusion structure is located between the first side post and the second side post to form the second air gap.

10. A power supply structure for a variable frequency microwave oven, characterized in that, The power supply structure of the variable frequency microwave oven includes the transformer described in any one of claims 1-9.

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