Magnetic core structure, transformer and micro inverter

Abstract

The utility model provides a magnetic core structure, a transformer and a micro inverter, the magnetic core structure comprises two magnetic cores, and each magnetic core comprises a middle column, a middle column outer wall and a middle column outer wall; the first side column surrounds the middle column and comprises a first side column inner wall, a first side column outer wall and N openings, and N is a positive number larger than or equal to 1; the first space is formed by the first side column inner wall and the middle column outer wall; the second side column surrounds the first side column and comprises a second side column inner wall and K notches, and K is an integer larger than or equal to 1; the second space is formed by the first side column outer wall and the second side column inner wall; the magnet yoke is arranged at the bottoms of the first space and the second space and is connected with the first side column, the second side column and the middle column; the middle columns, the first side columns, the second side columns and the openings of the two magnetic cores are oppositely arranged. The problem that an existing magnetic core structure cannot give consideration to heat dissipation and EMC interference is solved, the heat dissipation capacity can be improved, and EMC interference can be reduced.

Description

Technical Field

[0001] This application belongs to the technical field of transformers, and particularly relates to a magnetic core structure, a transformer, and a micro-inverter. Background Art

[0002] Conventional magnetic cores with structures such as EE type, ER type, EQ type, PQ type, and P type can all be used in the design of integrated transformers, but each has its own defects. The EE-type magnetic core has good heat dissipation, but serious magnetic leakage, and relatively large actual leakage inductance loss. The magnetic cores with structures such as ER type, EQ type, and PQ type are relatively balanced, but electromagnetic compatibility (EMC) interference still exists. The P-type magnetic core has good shielding effect, but poor heat dissipation effect.

[0003] Therefore, there is an urgent need to provide a magnetic core structure that takes into account both heat dissipation and reduction of EMC interference. Summary of the Utility Model

[0004] Embodiments of this application provide a magnetic core structure, a transformer, and a micro-inverter to solve the problem that the existing magnetic core structure cannot take into account both heat dissipation and EMC interference, and can improve the heat dissipation ability and reduce EMC interference.

[0005] In a first aspect, this application provides a magnetic core structure, including two magnetic cores. Each magnetic core includes: a central column, which includes an outer wall of the central column; a first side column surrounding the central column, which includes an inner wall of the first side column, an outer wall of the first side column, and N openings, where N is a positive number greater than or equal to 1; a first space formed by the inner wall of the first side column and the outer wall of the central column; a second side column surrounding the first side column, which includes an inner wall of the second side column and K notches, where K is an integer greater than or equal to 1; a second space formed by the outer wall of the first side column and the inner wall of the second side column; a magnetic yoke provided at the bottom of the first space and the second space and connecting the first side column, the second side column, and the central column; the central columns, the first side columns, the second side columns, and the openings of the two magnetic cores are arranged oppositely.

[0006] In a possible implementation manner, the height of the first side column is lower than that of the central column.

[0007] In a possible implementation manner, there is a first air gap between the central columns of the two magnetic cores; there is a second air gap between the first side columns of the two magnetic cores, and the second air gap is greater than the first air gap.

[0008] In a possible implementation manner, the notches of the two magnetic cores are arranged oppositely.

[0009] In a possible implementation manner, it further includes a heat dissipation material, and the heat dissipation material is filled in the notches.

[0010] In a possible implementation manner, the magnetic yoke includes slots for communicating the openings and the notches.

[0011] In a possible implementation, K is an integer greater than or equal to 2, and the K notches are evenly arranged on the second side post.

[0012] In a second aspect, the present application provides a transformer, including a first winding, a second winding, and a magnetic core structure as described in any one of the above; the first winding is arranged on the middle post and led out through an opening; the second winding is arranged on the first side post.

[0013] In a possible implementation, it further includes a heat dissipation material; the heat dissipation material is filled in the notches, and the first winding and the second winding are in contact with the heat dissipation material.

[0014] In a third aspect, the present application provides a micro-inverter, including a housing and a circuit main board arranged in the housing, and at least one transformer as described in any one of the above is installed on the circuit main board.

[0015] The magnetic core structure provided by the embodiments of the present application includes but is not limited to the following technical effects:

[0016] The magnetic core structure forms a first space and a second space through the middle post, the first side post, and the second side post. Furthermore, the first winding can be accommodated in the first space, and the second winding can be accommodated in the second space. By arranging K notches on the second side post, the heat dissipation material can be filled into the notches subsequently, so that the heat dissipation material can completely penetrate into the magnetic core and the winding to achieve heat dissipation. Further, by surrounding the middle post with the first side post, surrounding the first side post with the second side post, and surrounding the first side post with the second winding, the electromagnetic compatibility of the magnetic core structure is better, the electromagnetic interference generated to the outside is small, and the anti-interference ability is improved. Description of the Drawings

[0017] Figure 1 is a schematic diagram of a magnetic core structure provided by an embodiment of the present application.

[0018] Figure 2 is an exploded schematic diagram of a transformer provided by an embodiment of the present application.

[0019] Figure 3 is a schematic diagram of a transformer structure provided by an embodiment of the present application.

[0020] Description of the Main Component Symbols

[0021]

[0022] Detailed Embodiments

[0023] It should be noted that the terms "first" and "second" in the description, claims and drawings of this application are used to distinguish similar objects, rather than to describe a specific order or sequence. In the description, claims and drawings of this application, unless otherwise specified, " / " means "or". For example, A / B may mean A or B. For example, A and / or B may mean: A exists alone, A and B exist simultaneously, and B exists alone, these three situations.

[0024] It can be understood that the connection relationship described in this application refers to direct or indirect connection. For example, A is connected to B or A is electrically connected to B, which can either be that A is directly connected to B, or that A and B are indirectly connected through one or more other electrical components. For example, it can be that A is directly connected to C and C is directly connected to B, so that A and B are connected through C.

[0025] Some embodiments will be described below in conjunction with the drawings. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0026] As the power of a single photovoltaic panel continues to increase, the power of the micro-inverter also increases accordingly. To maintain a compact form factor, the power density is usually increased, which in turn poses higher challenges to the heat dissipation and electromagnetic compatibility (EMC) of the inverter. Generally speaking, micro-inverters all adopt isolated-type solutions, which can be generally divided into three categories: single-stage, DC-DC-AC, and DC-AC-AC. Common topologies can include flyback, forward, push-pull, resonant type, and single-phase dual active bridge (DAB), etc. Among them, the LLC resonant converter takes advantage of its soft-switching characteristics and can achieve a relatively high overall efficiency especially near the resonant point. The resonant inductor, resonant capacitor, and transformer (magnetizing inductor) constitute the key parameters of the resonant cavity. Usually, the leakage inductance of the transformer is used to integrate the resonant inductor (partially or completely) to improve the power density, but this also further deteriorates the heat loss of the transformer. In addition, the compact spatial layout of the micro-inverter makes the transformer have a greater impact on EMC. Traditional magnetic cores such as EE type, ER type, EQ type, PQ type, P type, etc. can be used for the integrated transformer design, but each has its own defects. The EE type magnetic core has good heat dissipation, but serious magnetic leakage and relatively large actual leakage inductance loss. The magnetic cores of ER type, EQ type, and PQ type are relatively balanced, but the eddy current loss and EMC interference caused by magnetic leakage to the case still exist. The P type magnetic core has good shielding effect, but poor heat dissipation effect.

[0027] In view of this, the embodiments of the present application provide a magnetic core structure, a transformer, and a micro-inverter, which solve the problem that the existing magnetic core structure cannot balance heat dissipation and EMC interference, and can improve the heat dissipation ability and reduce EMC interference.

[0028] Please refer to Figure 1 , and an exemplary introduction to the magnetic core 100 provided by the embodiments of the present application is given. As Figure 1 shown, the magnetic core 100 includes a central column 10, a first side column 20, a first space 30, a second side column 40, a second space 50, and a magnetic yoke 60. The central column 10 includes a central column outer wall 11. The first side column 20 surrounds the central column 10. The first side column 20 includes a first side column inner wall 21, a first side column outer wall 22, and N openings 23, where N is a positive number greater than or equal to 1. The first space 30 is formed by the first side column inner wall 21 and the central column outer wall 11. The second side column 40 surrounds the first side column 20, and the second side column 40 includes a second side column inner wall 42. The second space 50 is formed by the first side column outer wall 22 and the second side column inner wall 42. The magnetic yoke 60 is disposed at the bottom of the first space 30 and the second space 50 and connects the first side column 20, the second side column 40, and the central column 10.

[0029] In the embodiments of the present application, the first space 30 and the second space 50 are formed by the central column 10, the first side column 20, and the second side column 40. Furthermore, the first winding 200 can be accommodated in the first space 30 (as Figure 2 shown), and the second winding 300 can be accommodated in the second space 50 (as Figure 2 shown). By providing K notches on the second side column, heat dissipation materials can be filled into the notches subsequently, so that the heat dissipation materials can completely penetrate into the magnetic core and the windings, realizing heat dissipation. Further, since the first side column 20 surrounds the central column 10, the second side column 40 surrounds the first side column 20, and the second winding 200 surrounds the first side column 20, the electromagnetic compatibility of the magnetic core 100 is good, the electromagnetic interference generated to the outside is small, and the anti-interference ability is improved.

[0030] The following specifically introduces the settings of each component on the magnetic core 100.

[0031] In the embodiments of the present application, the central column 10 is used for winding the first winding 200, and the central column 10 includes a central column outer wall 11. Specifically, the first winding 200 can be wound on the central column outer wall 11. When the central column 10 is an integral body, the central column outer wall 11 is the outer surface of the integral body, and the lower surface of the central column 10 is connected to the magnetic yoke 60. The upper surface of the central column 10 is disposed opposite to the upper surface of the central column 10 of another magnetic core 100 (as Figure 2 shown).

[0032] In some embodiments, the central column 10 may include a plurality of sub-columns (not shown in the figures), the plurality of sub-columns are located in the middle of the magnetic core 100, and the plurality of sub-columns are spaced apart from each other. The plurality of sub-columns can be regarded as a whole, and then the first winding 200 can be arranged outside the whole. Specifically, one side of the plurality of sub-columns relative to the first side column 20 forms the outer wall of the central column, that is, one side of the plurality of sub-columns relative to the first side column 20 is the outside of the whole, and the first winding 200 passes through one side of the plurality of sub-columns relative to the first side column 20.

[0033] Among them, the central column 10 and the sub-columns may include, but are not limited to, the following shapes: cylinder, elliptic cylinder, cube, cuboid, etc., and the present application does not make specific limitations thereto.

[0034] In the embodiments of the present application, the central column 10 or the sub-columns may be integrally die-cast with the magnetic yoke 60, or the central column 10 or the sub-columns may be separate bodies.

[0035] In the embodiments of the present application, the first side column 20 is used for winding the second winding 300. The arrangement of the first side column 20 needs to ensure that the second winding 300 surrounds the outer periphery of the first winding 200 (such as the second winding 300 encloses the first winding 200), and can lead out the coils of the first winding 200.

[0036] Specifically, the first side column 20 surrounds the central column 10, and the first side column 20 includes a first side column inner wall 21, a first side column outer wall 22, and N openings 23, where N is a positive number greater than or equal to 1.

[0037] Among them, the first side column 20 surrounding the central column 10 may include, but is not limited to, the following situations:

[0038] Situation 1: The first side column 20 is a whole, and the first side column 20 is sleeved outside the outer wall 11 of the central column.

[0039] Exemplarily, as Figure 1 shown, the first side column 20 is a ring with one opening 23, and the ring with the opening 23 is sleeved outside the outer wall 11 of the central column.

[0040] Situation 2, when the first side column 20 includes two or more sub-side columns, the two or more sub-side columns are evenly arranged outside the outer wall 11 of the central column.

[0041] Exemplarily, taking the sub-side column as an arc column as an example, the first side column 20 includes two arc columns (not shown in the figures), the two arc columns are evenly arranged outside the outer wall 11 of the central column, and the two arc columns are arranged oppositely, that is, the central column 10 is located in the space formed by surrounding the two arc columns.

[0042] It can be understood that the first side column 20 may include more sub-side columns, such as 5, 6, 7, etc. sub-side columns, and the multiple sub-side columns are evenly arranged outside the outer wall 11 of the middle column to surround the middle column 10.

[0043] In the embodiment of the present application, when the first side column 20 includes two or more sub-side columns, the air gap (i.e., the second air gap) of the first side column 20 can be segmented into multiple small air gaps, thereby reducing the high-frequency losses of the first winding 200 and the second winding 300 caused by the fringe flux.

[0044] The first side column 20 and the sub-side columns may include, but are not limited to, the following shapes: cylinder, elliptic cylinder, arc column, cube, cuboid, etc., and the present application does not make specific limitations thereto.

[0045] In the embodiment of the present application, when the first side column 20 is an integral body, an opening 23 is provided thereon. When the first side column 20 includes two or more sub-side columns, it may include two or more openings 23 thereon. For example, when the first side column 20 includes two sub-side columns and the two sub-side columns are spaced apart from each other, the first side column 20 may include two openings 23.

[0046] In the embodiment of the present application, at least one opening 23 in the first side column 20 is used for the coil of the first winding 200 to extend out / lead out.

[0047] Among them, the form of the opening 23 includes, but is not limited to: rectangle, square, sector, and the present application does not make specific limitations thereto.

[0048] In the embodiment of the present application, the inner wall 21 of the first side column is the side of the side wall of the first side column 20 close to the middle column 10, and the outer wall 22 of the first side column is the side of the side wall of the first side column 20 far from the middle column 10.

[0049] In the embodiment of the present application, the first space 30 is formed by the inner wall 21 of the first side column and the outer wall 11 of the middle column, that is, the first space 30 is formed between the inner wall 21 of the first side column and the outer wall 11 of the middle column.

[0050] In the embodiment of the present application, the height of the first side column 20 is lower than that of the middle column 10. Based on the fact that the height of the first side column 20 is lower than that of the middle column 10, thus, when two magnetic cores 100 are combined, there is a first air gap between the middle columns 10 of the two magnetic cores 100, and there is a second air gap between the first side columns 20 of the two magnetic cores 100, and the second air gap is greater than the first air gap.

[0051] Among them, the first air gap and the second air gap may be air or other filling solid materials with a magnetic permeability approximate to that of air, and are used to adjust the equivalent magnetic permeability of the leakage magnetic path to adjust the magnitude of the leakage inductance.

[0052] In the embodiments of the present application, the first side column 20 or the sub-side column can be integrally die-cast with the yoke 60, or the first side column 20 or the sub-side column can be a separate entity.

[0053] In the embodiments of the present application, the second side column 40 surrounds the first side column 20. There are K notches 41 provided on the second side column 40, and it has a second side column inner wall 42, where K is an integer greater than or equal to 1. The number of K and N can be the same or different. In some embodiments, K is greater than N.

[0054] In the embodiments of the present application, the K notches 41 are evenly arranged on the second side column 40. By using the opened notches 41, heat dissipation materials (not shown in the figure) can completely penetrate into the inside of the magnetic core 100 and windings (such as the first winding 200 and the second winding 300).

[0055] Among them, the second side column inner wall 42 is the side of the second side column 40 close to the first side column 20 on the side wall.

[0056] Among them, the second side column 40 can include, but is not limited to, the following shapes: cylinder, elliptic cylinder, cube, cuboid, etc.

[0057] Among them, the forms of the notches 41 include, but are not limited to: rectangle, square, sector, and the present application does not make specific limitations on this.

[0058] In the embodiments of the present application, the second space 50 is formed by the outer wall 22 of the first side column and the inner wall 42 of the second side column, that is, the second space 50 is formed between the outer wall 22 of the first side column and the inner wall 42 of the second side column.

[0059] In the embodiments of the present application, the yoke 60 includes a slot 61, and the slot 61 is used to communicate the opening 23 and the notch 41.

[0060] As Figure 1 shown, the slot 61 communicates the opening 23 and the notch 41, and thus the first winding 200 and the second winding 300 can be led out therefrom.

[0061] It can be understood that the second winding 300 can also be led out through the notch 41 on the second side column 40.

[0062] In some other embodiments, the yoke 60 includes a plurality of slots 61. Except for the slot 61 for communicating the opening 23 and the notch 41, the remaining other slots 61 are only used to communicate with the opening 23. The slot 61 for communicating with the opening 23 can be provided around, in the middle or other positions of the yoke 60, and the present application does not make specific limitations on this.

[0063] As Figure 1As shown, four slots 61 for communicating with the opening 23 can be provided around the yoke 60, and the second side column 40 is also provided with four openings 23 around the connection with the yoke 60, and the four slots 61 communicate with the four openings 23.

[0064] In the embodiment of the present application, the shape of the yoke 60 includes but is not limited to: square or rectangle, and the present application does not make specific limitations thereto.

[0065] Please refer to Figure 2 and Figure 3 for an exemplary introduction to the transformer 1000 provided by the embodiment of the present application.

[0066] The transformer 1000 provided by the embodiment of the present application includes the magnetic core structure 1, the first winding 200, and the second winding 300 provided by the embodiment of the present application.

[0067] The magnetic core structure 1 provided by the embodiment of the present application includes two of the above-mentioned magnetic cores 100. The structures of the two magnetic cores 100 included in the magnetic core structure 1 are similar, and the central column 10, the first side column 20, the second side column 40, the opening 23, and the notch 41 of the two magnetic cores 100 are arranged oppositely.

[0068] In the embodiment of the present application, the magnetic core structure 1 may further include a heat dissipation material (not shown in the figure), and the heat dissipation material is filled in the notch 41.

[0069] Among them, the heat dissipation material may include high thermal conductivity insulating silicone materials and other heat-conducting filling materials, such as thermal conductive glue, and the present application does not make specific limitations thereto.

[0070] The first winding 200 is arranged on the central column 10 and is accommodated in the first space 30, and the first winding 200 is led out through the opening 23.

[0071] The second winding 300 is arranged on the first side column 20 and is accommodated in the second space 50.

[0072] The first winding 200 and the second winding 300 include but are not limited to: film-wrapped litz wire, silk-wrapped litz wire, or triple-insulated litz wire, and the present application does not make specific limitations thereto.

[0073] In some embodiments, smaller copper wire windings can be selected, and some measures for solving EMC (such as differential mode inductors, X and Y capacitors) and investment time can be omitted.

[0074] In the embodiment of the present application, the heat dissipation material is filled in the notch 41, and the first winding 200 and the second winding 300 are in contact with the heat dissipation material. Since the first winding 200 and the second winding 300 are in contact with the heat dissipation material and the heat conduction speed of the heat dissipation material is fast, the first winding 200 and the second winding 300 can conduct heat through contact with the heat dissipation material, so as to improve the heat dissipation efficiency.

[0075] In the embodiment of the present application, based on the fact that the height of the first side leg 20 is lower than that of the middle leg 10, the second air gap is greater than the first air gap, thereby realizing controlling the leakage inductance of the transformer 1000 by adjusting the size of the air gap of the first side leg 20, and further realizing integrating the resonant inductor (partially or completely) by using the leakage inductance of the transformer 1000, reducing the product size, increasing the product power density, and reducing the cost.

[0076] Furthermore, by providing corresponding slots 61 and notches 41 on the second side leg 40 and the yoke 60, the heat dissipation material such as thermal conductive glue can be completely infiltrated into the magnetic core 100 and the windings by using the opened notches 41 and / or slots 61, so as to realize heat dissipation and fixation of the transformer 1000 through potting measures, effectively reducing the temperature rise speed of the transformer 1000, improving the environmental tolerance of the transformer 1000, and prolonging the service life of the transformer 1000.

[0077] Furthermore, since the first side leg 20 surrounds the middle leg 10, the second side leg 40 surrounds the first side leg 20, and the second winding 200 surrounds the first side leg 20, the electromagnetic compatibility of the magnetic core 100 is good, the electromagnetic interference generated to the outside is small, and the anti-interference ability is improved.

[0078] Furthermore, when the first side leg 20 includes two or more sub-side legs, the air gap (i.e., the second air gap) of the first side leg 20 can be segmented into multiple small air gaps, and thus the high-frequency losses of the first winding 200 and the second winding 300 caused by the fringe flux can be reduced.

[0079] The embodiment of the present application provides a micro-inverter, which includes a housing and a circuit main board arranged in the housing, and the above-mentioned transformer 1000 is installed on the circuit main board. This micro-inverter can be applied to a resonant topology.

[0080] Among them, the micro-inverter can be a one-to-one, one-to-two, one-to-four, one-to-six, one-to-eight, etc. micro-inverter, which are respectively applicable to photovoltaic systems with one-way photovoltaic panel output, two-way photovoltaic panel output, four-way photovoltaic panel output, six-way photovoltaic panel output, and eight-way photovoltaic panel output.

[0081] An embodiment of the present application provides a photovoltaic system, which includes a photovoltaic power generation unit and the above-mentioned micro-inverter. The output of the photovoltaic power generation unit is electrically connected to the micro-inverter. Among them, the specific structure of the micro-inverter refers to the above-mentioned embodiment. Since this photovoltaic system adopts all the technical solutions of all the above-mentioned embodiments of the micro-inverter, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be elaborated one by one here.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and not to limit them. In the actual application process, all the content of the technical solutions described in any embodiment of the present application can be implemented, or some content can be added, or some content can be deleted, or some content can be changed / replaced. Although the present application has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A magnetic core structure, characterized in that: The invention comprises two magnetic cores, each of which comprises: A central column, comprising a central column outer wall; A first side column, surrounding the middle column, comprising a first side column inner wall, a first side column outer wall and N openings, where N is a positive number greater than or equal to 1; A first space is formed by the inner wall of the first side column and the outer wall of the middle column; A second side column, surrounding the first side column, comprising an inner wall of the second side column and K notches, where K is an integer greater than or equal to 1; A second space is formed by the outer wall of the first side column and the inner wall of the second side column; A magnetic yoke, disposed at the bottom of the first space and the second space and connecting the first side column, the second side column and the middle column; The middle column, the first side column, the second side column and the opening of the two magnetic cores are arranged opposite to each other.

2. The magnetic core structure according to claim 1, characterized in that: The first side column is lower in height than the middle column.

3. The magnetic core structure according to claim 2, characterized in that: There is a first air gap between the middle columns of the two magnetic cores; there is a second air gap between the first side columns of the two magnetic cores, and the second air gap is larger than the first air gap.

4. The magnetic core structure according to claim 1, characterized in that: It also includes a heat dissipation material, which is filled in the gap.

5. The magnetic core structure according to claim 4, characterized in that: K is an integer greater than or equal to 2, and the K notches are evenly arranged on the second side column.

6. The magnetic core structure according to claim 1, characterized in that: The notches and the openings of the two magnetic cores are arranged opposite to each other.

7. The magnetic core structure according to any one of claims 1 to 6, characterized in that: The magnetic yoke comprises a slot, and the slot is used to connect the opening and the notch.

8. A transformer, characterized in that: It comprises a first winding, a second winding and a magnetic core structure as described in any one of claims 1 to 7; the first winding is arranged on the middle column and led out through the opening; the second winding is arranged on the first side column.

9. The transformer according to claim 8, characterized in that Also included are heat dissipation materials; The heat dissipation material is filled in the gap, and the first winding and the second winding are in contact with the heat dissipation material.

10. A micro inverter, characterized in that: The invention comprises a housing and a circuit mainboard arranged in the housing, wherein at least one transformer according to any one of claims 8 to 9 is mounted on the circuit mainboard.

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