Disclosure of Invention
Therefore, the present invention is directed to a winding structure with low height and high space utilization, which can ensure a lower winding thickness and a higher filling rate of a magnetic core window while ensuring a lower winding impedance of a winding, and provides a powerful support for further reducing the space, particularly the height, of a power converter.
A first aspect of the present invention provides a winding structure having a low height and a high space utilization, characterized by comprising:
The winding is formed by winding a plurality of turns of winding units;
a window formed at the center of the winding;
The enveloping shape of the cross section of the winding unit is provided with an enveloping shape long side and an enveloping shape short side, and the ratio of the enveloping shape long side to the enveloping shape short side is n, wherein n is more than or equal to 2, and in practical application, n only needs to be close to an integer due to factors such as winding section deformation;
the winding unit comprises a vertical winding unit and a horizontal winding unit;
The vertical winding unit is a turn of winding unit close to the window, and the envelope shape of the vertical winding unit is arranged along the axis direction of the window;
The other turn winding units in the winding are all horizontal winding units, and the long side direction of the enveloping outline of the horizontal winding units is arranged along the radial direction of the window.
Preferably, the winding device further comprises a transition zone, and the parallel winding units are changed into the transition zone to form the vertical winding units.
Preferably, two adjacent turns of the winding units are transited in a layer-changing transition region, the kth turn of the winding unit is twisted by 90 degrees along a first direction when transiting to the (k-1) th turn, the kth turn of the winding unit is twisted by 90 degrees along a second direction when transiting to the (k+1) th turn from the other winding, and the first direction is clockwise or anticlockwise, and the second direction is opposite to the first direction.
Preferably, n is an integer.
Preferably, the total number of turns P of the winding unit is (n multiplied by m+1), wherein m is more than or equal to 1, and m is an integer.
Preferably, the winding unit includes at least two windings.
Preferably, in the winding, at least two of the windings are alternately arranged adjacently.
Preferably, at least two of the windings are alternately arranged adjacently in the axial direction of the window and the radial direction of the window, respectively.
Preferably, the winding is litz wire.
Preferably, the winding unit is a strand of winding.
Preferably, the windings are flat wires whose cross-section aspect ratio is an integer or simple integer ratio, again where values need only be close.
Preferably, the winding unit includes at least two sub-windings.
Preferably, the winding is provided with two leading-out terminals, and an included angle formed by the two leading-out terminals and the center of the window is 0-360 degrees.
The second aspect of the present invention also provides an application of a winding structure with low height and high space utilization, in a soft switching circuit, a winding unit with at least two windings is adopted, and a winding structure with low height and high space utilization, which takes litz wire as windings, is adopted.
A third aspect of the invention provides the use of a low-height high-space-utilization winding structure in a transformer with a frequency above 500kHz, using at least two different sets of windings of the transformer as winding units.
The invention has the following beneficial effects:
(1) The thickness of the winding can be greatly reduced, the loss of the winding can be reduced, and the power conversion efficiency can be improved while ensuring lower winding impedance;
(2) The invention has extremely high space utilization rate and can reduce the size of the magnetic core element, thereby realizing the reduction of the size of the power converter.
Detailed Description
The invention aims to provide a winding structure with low height and high space utilization rate, which can ensure that the winding has lower winding thickness and higher filling rate of a magnetic core window while ensuring lower winding impedance, and provides powerful support for further reducing the space, especially the height, of a power converter.
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
As shown in fig. 1 and 2, an embodiment of the present invention discloses a winding structure with low height and high space utilization, which includes:
the winding is formed by winding a plurality of turns of winding units;
A window 3 formed in the center of the winding;
the enveloping shape of the cross section of the winding unit is provided with an enveloping shape long side and an enveloping shape short side, and the ratio of the enveloping shape long side to the enveloping shape short side is n, wherein n is more than or equal to 2;
The winding unit comprises a vertical winding unit 1 and a horizontal winding unit 2, wherein the vertical winding unit 1 is a turn of winding unit close to the window 3, the envelope shape length of the vertical winding unit 1 is arranged along the axis direction of the window 3, other turns of winding units in the winding are all horizontal winding units 2, and the envelope shape length side direction of the horizontal winding unit is arranged along the radial direction of the window 3.
The winding is provided with a layer-changing transition zone 5, two adjacent winding units are in transition in the layer-changing transition zone 5, the winding units of the (k-1) th turn are twisted by 90 degrees along a first direction when in transition to the (k+1) th turn, the winding units of the kth turn are twisted by 90 degrees along a second direction when in transition to the (k+1) th turn, and the first direction is clockwise or anticlockwise, and the second direction is opposite to the first direction.
The winding unit comprises at least two windings, the total number of turns P of the winding unit is (n multiplied by m+1), wherein m is more than or equal to 1, and m is an integer.
As shown in fig. 3A, the winding unit of the present embodiment has two windings per turn, and has a total of 3 turns, wherein the vertical winding unit 1 has the 2 nd turn.
The winding of this embodiment is manufactured by first arranging two windings in a vertical direction and winding one turn along the window 3 to form a single turn vertical winding unit 1 denoted by k, then twisting the long side direction of the cross section envelope rectangle of the two windings by 90 ° in a counterclockwise direction at the layer change transition region 5 between the winding lead-out terminals 4, and winding one turn along the axis of the window 3 to form each turn horizontal winding unit 2 denoted by (k+1), (k-1), wherein the thickness of the winding is twice the winding diameter, and the thickness of the three turns winding wound by a single strand is 2 times the wire diameter, but the wire diameter is relatively large. Therefore, the winding structure can ensure lower winding impedance and simultaneously achieve lower winding thickness.
In other embodiments, the layer-changing transition region 5 may twist the long side direction of the cross-sectional envelope rectangle of the two strands by 90 ° clockwise, as shown in fig. 3B if the twisting directions when forming the respective one-turn horizontal winding units 2 denoted by (k+1), (k-1) are different.
As shown in fig. 3A and 3B, at least two windings are alternately disposed adjacent to each other in the winding. In particular, in fig. 3A, at least two windings are alternately adjacent to each other in the axial direction of the window 3 and the radial direction of the window 3, and windings of two parallel coils are alternately arranged in any cross section, so that the two coil turns are equivalent in length, the impedance thereof is equal, and the current is uniformly distributed in the two coils, and thus, a lower loss can be obtained. And the loop current is not formed between the two coils due to inconsistent impedance, so that extra loss is avoided. Thus, the winding has the significant advantage of low losses. Furthermore, due to the characteristic that the windings of the two parallel coils are alternately arranged, leakage magnetic flux balance can be brought, circulation of the two coils is effectively avoided, and the effect of current sharing and parallel connection is achieved.
The winding has the shortest distance from the center in the direction around the window 3, so the length of each turn of the winding is shorter, and therefore, lower winding impedance can be obtained, which has important significance for reducing winding loss and improving the efficiency of power supply conversion. In addition, since the winding adopts a double-strand parallel winding structure, two coils can be considered to be connected in parallel. The layer-changing transition zone 5 between the winding pins has a certain winding structure due to the lack of winding turns, so that the winding filling rate of the zone is slightly lower, and the windings at the other positions are efficiently filled in the space of the magnetic core window. Therefore, the winding structure has extremely high space utilization. This has a positive effect on reducing the size of the core element and thus the power converter.
It should be noted that the wire used in the double-stranded parallel winding can be adaptively selected according to different use conditions such as frequency, current and the like, such as single-stranded insulated wire, single-stranded enameled wire, enameled litz wire, wire-wrapped litz wire, self-adhesive litz wire, three-layer insulated single wire, three-layer insulated litz wire and the like.
It should be noted that the angle formed by the leading-out terminal 4 of the winding and the center of the window 3 can be freely set between 0 ° and 360 ° according to the application requirement.
Example two
On the basis of the first embodiment, the winding can be provided with more turns, and the total number of turns P of the winding unit is (n multiplied by m+1), wherein m is more than or equal to 1, and m is an integer.
In this embodiment, the winding unit is provided with 5 turns, where the 1 st turn and the 2 nd turn are located in the first layer, and the 4 th turn and the 5 th turn are located in the second layer, as shown in fig. 4, and other technical features are similar to those of embodiment 1, and are not repeated.
Example III
On the basis of the first embodiment, the winding unit may be further provided with a plurality of winding wires wound in parallel to each other to provide 3 winding wires wound in parallel to each other, for example, as shown in fig. 5, which is adjacent to one turn of the center pillar denoted by k, and the long side direction of the envelope rectangle thereof is parallel to the axis direction of the window 3. One end of the kth turn is wound to form a (k-1) th turn, the other end is wound to form two (k+1) th turns and a (k+2) th turn, and other technical characteristics and embodiments are similar and are not repeated.
In a preferred embodiment, the winding unit comprises at least two sub-windings, and the different wires wound in parallel may be different windings of a transformer. For example, two windings of the transformer are wound in parallel, so that the two windings are tightly and uniformly staggered and wound, more excellent coupling can be realized, and the transformer is particularly suitable for scenes requiring low leakage inductance, such as scenes with the frequency of more than 500 kHZ.
Example IV
As shown in fig. 6, in order to achieve practical application, the flat wire may be used instead of the double-stranded wire, and the outer contour of the flat wire may be flat, or a single-stranded rectangular flat copper wire, a flat litz wire, a laminated copper foil flat wire, or the like may be selected as required in practical application, and the ratio of the long side to the short side of the envelope of the cross section of the formed winding unit may be only approximate to an integer.
In summary, the multi-strand parallel winding method provided by the invention not only can realize low height and fully utilize flat space, but also has small leakage magnetic flux between multi-strand parallel wires. When the multi-strand is connected in parallel and wound, the uniformity of flow among the strands is good. When the multi-winding transformer is used for multi-strand parallel winding, extremely low leakage inductance among windings can be realized. The invention is particularly suitable for the parallel winding of litz wire in a plurality of strands (since in the case of a single solid copper wire, it is possible to wind directly with a flat copper wire instead of having to wind in a plurality of strands). Since litz wire is particularly suitable for scenes with a large ac component, typically soft-switching high-frequency converters. Because of the soft switching circuit, a larger ripple current is required to achieve zero voltage turn-on of the power device. Because the ac resistance of litz wire can be close to dc resistance, whereas the ac resistance of solid copper wire can be greater than 5 times or even more than 10 times the dc resistance. Therefore, the invention can not only realize the purpose that the litz wire cannot be realized, but also greatly improve the efficiency, thereby realizing the real high-frequency small-volume high-efficiency contribution.
In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.