Inductor structure and power converter

Abstract

The utility model discloses an inductance structure and a power converter, which comprises a plurality of phases of windings and an internal magnetic core positioned in each phase of winding, and one end of each internal magnetic core is connected to the same common magnetic core. According to the utility model, the end side of each phase of inductance magnetic core is connected to the same common magnetic core, and the magnetic resistance of the common magnetic core is far smaller than the air magnetic resistance, so that the original leakage flux between two phases of windings is absorbed by the common magnetic core, that is, the leakage magnetic field intensity on the outer side of the common magnetic core is greatly reduced, and the electromagnetic influence on external devices is avoided. The projection outline of the common magnetic core is tangent to the outline of the internal magnetic core, so that the size of the common magnetic core is reduced under the condition that leakage flux is reduced as much as possible and the operation reliability of a circuit is improved, and the cost is saved.

Description

Technical Field

[0001] The utility model relates to the technical field of inductance, in particular to an inductance structure and a power converter. Background Art

[0002] The three-phase voltage source converter includes a three-phase voltage source inverter and a three-phase voltage source rectifier. For the three-phase voltage source converter, the three-phase power inductor on the AC side is responsible for reducing the input current ripple, achieving a high power factor and reducing the current distortion rate on the AC side.

[0003] Current three-phase power inductors utilize a discrete structure, with the inductor core positioned relatively close to the circuit board. As converters move toward higher power density, circuit board areas are shrinking, inevitably requiring the placement of power or sampling circuits around and beneath the inductor. However, three-phase discrete inductors generate a significant amount of leakage flux near the circuit board. This leakage flux can induce an electromotive force in the power or sampling circuitry on the circuit board, potentially interfering with the safe and reliable operation of the converter.

[0004] Therefore, how to reduce the end-side magnetic leakage of multi-phase inductors has become a technical problem that needs to be solved urgently in the industry. Utility Model Content

[0005] To solve the problem of end-side magnetic leakage in multi-phase inductors, the present invention proposes an inductor structure such that the end sides of the inductor cores of each phase are connected to the same common magnetic core, thereby reducing the magnetic leakage of the inductor and further providing a power converter.

[0006] In a first aspect, the present invention provides an inductor structure, comprising several phase windings and an internal magnetic core located within the winding of each phase, wherein one end of all the internal magnetic cores is connected to the same common magnetic core.

[0007] In combination with the first aspect, in some embodiments, the winding of each phase includes a first coil and a second coil connected in series, the internal magnetic core includes a first magnetic core arranged in the first coil and a second magnetic core located in the second coil, and one end of the first magnetic core and the second magnetic core are connected to the common magnetic core.

[0008] In combination with the first aspect, in some embodiments, the other ends of the first magnetic core and the second magnetic core of the winding of each phase are respectively connected through end magnetic cores.

[0009] In combination with the first aspect, in some embodiments, in the axial direction of the winding, the projection of the end magnetic core covers the first magnetic core and the second magnetic core.

[0010] In combination with the first aspect, in some embodiments, an end projection contour of the end magnetic core is tangent to a contour of the inner magnetic core.

[0011] In combination with the first aspect, in some embodiments, the first magnetic core and the second magnetic core are cylindrical magnetic cores.

[0012] In combination with the first aspect, in some embodiments, a first insulating sheet is provided between the first coil and the second coil.

[0013] In combination with the first aspect, in certain embodiments, in the axial direction of the winding, the projection of the common magnetic core covers the inner magnetic core of the winding of each phase.

[0014] In combination with the first aspect, in some embodiments, a projected outline of the common magnetic core is tangent to an outline of the cylindrical magnetic core.

[0015] In combination with the first aspect, in some embodiments, the common magnetic core is a rectangular plate, and the four corners of the rectangular plate are rounded corners corresponding to the ends of the columnar magnetic core.

[0016] In combination with the first aspect, in some embodiments, the several windings are arranged in parallel on the common magnetic core along the same preset direction, and the common magnetic core includes a bottom magnetic core connected to the end of the internal magnetic core and a leakage-proof magnetic core located at both ends of the bottom magnetic core in the preset direction, the leakage-proof magnetic core extends toward one side of the winding relative to the bottom magnetic core, the several windings are located between the two leakage-proof magnetic cores, and the leakage-proof magnetic core is perpendicular to the bottom magnetic core and parallel to the winding direction.

[0017] In combination with the first aspect, in some embodiments, the common magnetic core includes a bottom magnetic core connected to ends of the inner magnetic cores, and an anti-leakage magnetic core surrounding the plurality of windings is provided at an edge of the bottom magnetic core.

[0018] In combination with the first aspect, in some embodiments, the common magnetic core is disposed on a base, and in the axial direction of the winding, a projection of the base covers and is larger than the common magnetic core.

[0019] In combination with the first aspect, in some embodiments, a second insulating sheet is provided between the windings of each phase.

[0020] In combination with the first aspect, in some embodiments, the winding of each phase includes a first coil and a second coil connected in series, and the common magnetic core is provided with pin through holes for the pins of the first coil and the second coil to pass through respectively, and the pin through holes are through holes with flat cross-sections, and the pins have flat cross-sections that match the cross-sections of the pin through holes, so that the pins cannot rotate relative to the pin through holes, and the length direction of the cross-section of the first coil pin is perpendicular to the length direction of the cross-section of the second coil pin.

[0021] In combination with the first aspect, in some embodiments, the common magnetic core is disposed on a base, and a pin through-hole corresponding to the pin is provided on the base.

[0022] In a second aspect, the utility model provides a power converter including the aforementioned inductor structure.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention connects the ends of each phase's inductor core to a common core. Because the shared core's magnetic resistance is much lower than the air's, magnetic flux leakage between the two phase windings is absorbed by the shared core. This significantly reduces the magnetic field strength outside the shared core, thus preventing electromagnetic interference with external circuits and electrical components. The projected outline of the shared core is tangent to the outline of the internal core, and the shared core is tangent to both the end cores and the internal core, minimizing its volume. This minimizes magnetic flux leakage while minimizing circuit reliability, thereby reducing the shared core's volume and thus saving costs. The present invention includes an insulating sheet between the first and second coils, as well as between each phase's windings, to achieve optimal electrical insulation between closely spaced windings. The material used for the insulating sheet should possess both excellent insulating properties and superior thermal conductivity. The windings on either side of the insulating sheet should be placed as close together as possible, minimizing the spacing between them to facilitate heat transfer between the two windings, thereby increasing the heat dissipation area and reducing thermal resistance. This allows for mutual heat conduction between the three-phase windings, thereby increasing the heat dissipation area. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention is described in detail below with reference to specific embodiments and accompanying drawings. To illustrate details and facilitate understanding of its principles, the drawings are not necessarily drawn to scale, and similar reference numerals may describe similar components in different views. The accompanying drawings generally illustrate the embodiments discussed herein by way of example and not limitation. Among them:

[0026] Figure 1 is an exploded schematic diagram of the inductor structure of Example 1;

[0027] Figure 2 is a three-dimensional schematic diagram of the inductor structure of Example 1;

[0028] Figure 3 is a three-dimensional schematic diagram of the inductor structure of Example 1 from another angle;

[0029] Figure 4 is a schematic diagram of the inductor structure of the second embodiment.

[0030] In the figure, 1, first coil; 2, second coil; 3, first magnetic core; 4, second magnetic core; 5, common magnetic core; 6, end magnetic core; 7, pin; 8, pin through hole; 9, pin through hole; 10, base; 11, fixing hole; 12, first insulating sheet; 501, bottom magnetic core; 502, leakage-proof magnetic core; 13, second insulating sheet. DETAILED DESCRIPTION

[0031] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments, and the following embodiments do not limit the utility model involved in the claims. In addition, not all combinations of features described in the embodiments are necessarily required for the solution of the utility model.

[0032] The principle and structure of the present invention are described in detail below with reference to the accompanying drawings and embodiments.

[0033] Example 1

[0034] like Figure 1 、 2 As shown in FIG. 3 , an inductor structure includes several phase windings and an internal magnetic core located in the winding of each phase, and one end of all the internal magnetic cores is connected to the same common magnetic core 5.

[0035] This embodiment is a three-phase winding, used in a power converter. Each phase of the winding includes a first coil 1 and a second coil 2 connected in series. The internal magnetic core includes a first magnetic core 3 disposed within the first coil 1 and a second magnetic core 4 disposed within the second coil 2. One end of each of the first magnetic core 3 and the second magnetic core 4 is connected to a common magnetic core 5. The first magnetic core 3 and the second magnetic core 4 are cylindrical magnetic cores, around which the coils are wound. One end of each of the cylindrical magnetic cores is connected to the same common magnetic core 5. The multiple windings are arranged in parallel on the common magnetic core 5 along the same preset direction. The first coil 1 and the second coil 2 of each phase of the winding are arranged along a second direction, which is perpendicular to the second direction.

[0036] Since the magnetic resistance of the common magnetic core 5 is much smaller than the magnetic resistance of air, the leakage magnetic field between the two-phase windings is absorbed by the common magnetic core 5, that is, the leakage magnetic field strength outside the common magnetic core 5 is greatly reduced, avoiding electromagnetic influence on external devices and reducing electromagnetic interference to the circuit.

[0037] In the axial direction of the winding, that is, the axial direction of the cylindrical magnetic core, the projection of the common magnetic core 5 covers the inner magnetic core of the winding of each phase, so as to reduce magnetic leakage.

[0038] Furthermore, the projected contour of the common magnetic core 5 is tangent to the side profile of the inner magnetic core. This reduces the volume of the common magnetic core 5 while minimizing magnetic leakage and improving circuit reliability, thereby saving costs. In this embodiment, the common magnetic core 5 is a rectangular plate with rounded corners corresponding to the ends of the cylindrical magnetic cores. This effectively prevents magnetic leakage while reducing the material used for the common magnetic core 5, thereby saving costs.

[0039] The other ends of the first magnetic core 3 and the second magnetic core 4 of each phase of the winding are connected via an end core 6, that is, each phase of the winding is provided with an end core 6, and the two ends of the end core 6 are connected to the first magnetic core 3 and the second magnetic core 4, respectively. The end core 6 connects the magnetic circuits of the first magnetic core 3 and the second magnetic core 4. In the axial direction of the winding, the projection of the end core 6 covers the first magnetic core 3 and the second magnetic core 4. Specifically, in this embodiment, the end projection contour of the end core 6 is tangent to the side contour surface of the internal magnetic core, that is, the end core 6 is a long strip magnet, and the end of the end core 6 has a semicircular end corresponding to the end of the columnar magnetic core, so that the surface of the columnar magnetic core is tangent to the surface of the end core 6. In this way, while reducing magnetic leakage, the use of magnetic core material is reduced, and the production cost is reduced.

[0040] The first coil 1 and the second coil 2 each have a pin 7 so that the coils can be connected to the circuit board through the pins. The common magnetic core is provided with pin through-holes 8 for the pins 7 of the first coil 1 and the second coil 2 to pass through, that is, three pin through-holes 8 for the pins of the first coil 1 to pass through are arranged on one side of the common magnetic core, and three pin through-holes 8 for the pins of the second coil 2 to pass through are arranged on the other side of the common magnetic core. The pin through-holes 8 are through-holes with a flat cross-section, and the pins have a flat cross-section that matches the cross-section of the pin through-holes 8. The cross-section of the pin 7 is a flat shape that is roughly similar to the cross-section of the pin hole, so that the pin can be inserted into the pin through-hole 8 and cannot rotate relative to the pin through-hole 8. The length direction of the cross-section of the pin of the first coil 1 The length direction of the cross section of the pin of the second coil 2 is perpendicular to each other, so that the directions of the two pin holes 8 are significantly different, avoiding incorrect insertion. The pin hole 8 of this embodiment is a waist-shaped hole, and the pin is a flat pin that matches the cross-sectional shape of the pin hole 8. That is, the cross section of the pin is wide in one direction and narrower in another direction, with the wider direction being the length direction. This prevents the pin from rotating relative to the pin hole 8. Before installing the winding, the length directions of the cross sections of the pins of the first coil 1 and the second coil 2 can also be arranged perpendicularly. In this way, when the pin 7 is inserted into the pin hole 8, the pins of different coils can only be inserted into the pin hole 8 with the same length direction, avoiding incorrect pin 7 insertion, that is, preventing the pin of the first coil 1 from being inserted into the pin hole 8 where the pin of the second coil 2 should be inserted. Of course, the cross section of the pin hole can also be a racetrack shape or an elliptical shape.

[0041] The shared magnetic core 5 is mounted on a base 10. The base 10 is provided with pin holes 9 corresponding to the pins 7, allowing the pins 7 to pass through the base 10 and connect to the circuit board of the power converter. The base 10 is also provided with fixing holes 11 for securing the core to the circuit board. Similar in cross-sectional shape to the pin holes 8, the pin holes 9 are also waist-shaped, facilitating the passage of the corresponding pins.

[0042] In the axial direction of the winding, the projection of the base 10 covers and is larger than the common magnetic core 5. The base 10 is parallel to the common magnetic core 5 and is a certain distance longer and wider than the common magnetic core 5, which can be selected to be several millimeters longer, to prevent the winding from being too close to other electrical components.

[0043] With the trend of high power density in converters, the volume of magnetic components has been severely compressed, and the spacing between the inductors and the windings inside the inductors is very narrow, which can easily cause a short circuit in the windings between the inductors, thereby causing failure of the three-phase power inductors and failure of the converter. Precisely because the winding spacing is very narrow, the traditional method of injecting insulating colloid between the inductors has become ineffective, and it is difficult for the colloid to penetrate deeply. Therefore, this embodiment adopts a method of providing a first insulating sheet 12 between the first coil 1 and the second coil 2, and a second insulating sheet 13 between the windings of each phase. The insulating sheet is usually made of insulating materials such as Nomic paper and ceramic sheets. More preferably, the material used for the insulating sheet should have good insulation properties and excellent thermal conductivity. At the same time, the windings on both sides of the insulating sheet should be as close as possible to reduce the spacing to facilitate heat transfer between the two windings, thereby increasing the heat dissipation area and reducing thermal resistance. The insulating sheet at least ensures that its shape and size can prevent close contact between the coils, that is, the width of the insulating sheet should be greater than or equal to the insulation requirement at the closest point between the coils but should be less than or equal to the width of the base 10, and the height of the insulating sheet should be higher than the height of the winding but lower than the height of the magnetic core. The first insulating sheet (12) and the second insulating sheet (13) can be an integrally formed insulating sheet; the first insulating sheet (12) and the second insulating sheet (13) can also be separate and different insulating sheets; wherein the first insulating sheet (12) includes multiple insulating sheets, and the second insulating sheet (13) also includes multiple insulating sheets.

[0044] Example 2

[0045] like Figure 4 As shown, unlike the above embodiment, the shared magnetic core 5 includes a bottom magnetic core 501 connected to the ends of the internal magnetic core and leakage-proof magnetic cores 502 located at both ends of the bottom magnetic core 501 in the preset direction. The leakage-proof magnetic cores 502 extend toward one side of the winding relative to the bottom magnetic core 501, and the windings are located between the two leakage-proof magnetic cores 502. In this embodiment, the bottom magnetic core 501 is a rectangular plate, and the leakage-proof magnetic cores 502 are baffle-shaped magnetic cores arranged on two opposite ends of the rectangular plate to prevent magnetic leakage from the windings at both ends. The leakage-proof magnetic cores are perpendicular to the bottom magnetic core and parallel to the winding direction.

[0046] Of course, it is also possible to adopt the following approach: a leakage-proof magnetic core 502 is provided around the edge of the bottom magnetic core 501 to surround the plurality of windings, that is, two baffle-shaped magnetic cores are also provided on the other two opposite end sides of the bottom magnetic core 501, so as to prevent the windings from leaking magnetic flux to the surroundings in all directions.

[0047] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope defined by the appended claims.

Claims

1. An inductor structure comprising a plurality of phase windings and an internal magnetic core located within each phase of the winding, characterized in that: One end of all the internal magnetic cores is connected to the same common magnetic core (5).

2. The inductor structure according to claim 1, characterized in that Each phase of the winding comprises a first coil (1) and a second coil (2) connected in series, the internal magnetic core comprises a first magnetic core (3) arranged in the first coil (1) and a second magnetic core (4) located in the second coil (2), and one end of each of the first magnetic core (3) and the second magnetic core (4) is connected to the common magnetic core (5).

3. The inductor structure according to claim 2, characterized in that: The other ends of the first magnetic core (3) and the second magnetic core (4) of each phase of the winding are respectively connected via end magnetic cores (6).

4. The inductor structure according to claim 3, characterized in that: In the axial direction of the winding, the projection of the end magnetic core (6) covers the first magnetic core (3) and the second magnetic core (4).

5. The inductor structure according to claim 4, characterized in that: The end projection contour of the end magnetic core (6) is tangent to the contour of the inner magnetic core.

6. The inductor structure according to claim 5, characterized in that: The first magnetic core (3) and the second magnetic core (4) are cylindrical magnetic cores.

7. The inductor structure according to claim 2, characterized in that: A first insulating sheet (12) is provided between the first coil (1) and the second coil (2).

8. The inductor structure according to claim 1, wherein: In the axial direction of the winding, the projection of the common magnetic core (5) covers the inner magnetic core of the winding of each phase.

9. The inductor structure according to claim 6, characterized in that: The projected profile of the common magnetic core (5) is tangent to the side profile surface of the cylindrical magnetic core.

10. The inductor structure according to claim 9, characterized in that: The common magnetic core (5) is a rectangular plate, and the four corners of the rectangular plate are rounded corners corresponding to the ends of the columnar magnetic core.

11. The inductor structure according to claim 8, wherein: The plurality of windings are arranged in parallel on the common magnetic core (5) along the same preset direction. The common magnetic core (5) comprises a bottom magnetic core (501) connected to the end of the internal magnetic core and leakage-proof magnetic cores (502) located at both ends of the bottom magnetic core (501) in the preset direction. The leakage-proof magnetic cores (502) extend toward one side of the winding relative to the bottom magnetic core (501), and the plurality of windings are located between the two leakage-proof magnetic cores (502).

12. The inductor structure according to claim 8, characterized in that: The common magnetic core (5) comprises a bottom magnetic core (501) connected to the ends of the inner magnetic cores, and an anti-leakage magnetic core (502) surrounding the plurality of windings is provided at the edge of the bottom magnetic core (501).

13. The inductor structure according to claim 12, wherein: The common magnetic core (5) is arranged on a base (10); in the axial direction of the winding, the projection of the base (10) covers and is larger than the common magnetic core (5).

14. The inductor structure according to claim 1, wherein: A second insulating sheet (13) is provided between the windings of each phase.

15. The inductor structure according to claim 1, wherein: Each phase of the winding comprises a first coil (1) and a second coil (2) connected in series, and the common magnetic core (5) is provided with a pin through hole (8) for the pins (7) of the first coil (1) and the second coil (2) to pass through respectively, the pin through hole (8) being a through hole with a flat cross section, the pin (7) having a flat cross section that matches the cross section of the pin through hole (8), so that the pin (7) cannot rotate relative to the pin through hole (8), and the length direction of the cross section of the pin (7) of the first coil (1) and the length direction of the cross section of the pin (7) of the second coil (2) are perpendicular to each other.

16. The inductor structure according to claim 15, characterized in that: The common magnetic core (5) is arranged on a base (10), and a pin (7) passing hole corresponding to the pin (7) is provided on the base (10).

17. A power converter, according to, characterized in that, The inductor structure comprises the inductor structure according to any one of claims 1 to 16.

Images