Sandwich winding LLC transformer with adjustable leakage inductance
By adjusting the distance between the primary and secondary windings using a sandwich winding method and sliding baffle components, the problem of difficult-to-control coupling degree in LLC transformers was solved, achieving low hysteresis loss and high leakage inductance, and improving power density and adaptability.
Patent Information
- Application Number
- CN202520204770.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-07
- Publication Date
- 2026-02-17
- Estimated Expiration
- 2035-02-07
AI Technical Summary
In existing LLC transformers, the primary and secondary windings are wound separately, making it difficult to control the degree of coupling, affecting the regulation of leakage inductance, resulting in high hysteresis loss and low efficiency.
The sandwich winding method is adopted, with the primary winding located in the middle third winding slot and the secondary winding located in the first and second winding slots on both sides. The relative distance between the primary and secondary windings is adjusted by a sliding baffle to control leakage inductance.
It reduces peak flux and hysteresis loss, increases power density, and adapts to the needs of different working environments. It has relatively large leakage inductance and is suitable for magnetically integrated LLC transformers.
Smart Images
Figure CN223927192U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of transformers, and more particularly to a sandwich-wound LLC transformer with adjustable leakage inductance. Background Technology
[0002] Among various switching power supplies, the LLC resonant topology is widely used in power conversion scenarios above 100W due to its ability to achieve zero-voltage soft-switching operation across the entire load range, significantly reducing switching losses of switching devices. The core design of the LLC resonant converter lies in the resonant cavity parameters composed of its resonant inductance Lr, magnetizing inductance Lm, and resonant capacitor C. In low-to-medium power applications, the parasitic leakage inductance Ls of the transformer primary side is often used as the resonant inductance Lr, meaning the resonant inductance is integrated into the LLC transformer. This approach simplifies power supply components, reduces power supply size, and increases power density. However, since the transformer leakage inductance is mainly related to the tightness of its coil coupling, it limits the choice of transformer structure and the design of resonant cavity parameters.
[0003] Existing technology uses a nested structure to wind the primary and secondary windings separately onto the central column of the magnetic core, and adjusts the spacing by using baffles to change the coupling degree between the primary and secondary windings, thereby obtaining the desired leakage inductance Ls. However, because the primary and secondary windings are wound separately, the coupling degree is difficult to control, which in turn affects the control of leakage inductance. Utility Model Content
[0004] This application provides a sandwich-wound LLC transformer with adjustable leakage inductance, which solves the problem of low efficiency caused by large hysteresis loss in traditional transformers with a master-slave structure, thereby improving power density.
[0005] Therefore, this application provides a sandwich-wound LLC transformer with adjustable leakage inductance, comprising:
[0006] A skeleton having a through-hole receiving cavity; a magnetic core is inserted into the receiving cavity;
[0007] A winding groove is wound around the outer wall of the receiving cavity;
[0008] A coil winding is wound in the winding slot;
[0009] A baffle is movably wound around the winding groove to divide the winding groove into a first winding groove and a second winding groove; the baffle is provided with a third winding groove, which is located between the first winding groove and the second winding groove.
[0010] The coil winding includes a primary winding and a secondary winding; the primary winding is wound in the third winding slot; the secondary winding is wound in the first winding slot and the second winding slot respectively; the secondary winding and the primary winding are arranged in a sandwich shape along the vertical direction of the magnetic core.
[0011] Furthermore, the secondary winding includes a first secondary winding and a second secondary winding; the first secondary winding is wound in the first winding slot; the second secondary winding is wound in the second winding slot, and the first secondary winding and the second secondary winding are arranged at intervals along the vertical direction of the magnetic core.
[0012] Furthermore, the baffle member further includes at least a first baffle and a second baffle; the first baffle is connected to the second baffle; the third winding groove is recessed on the side wall between the first baffle and the second baffle away from the outer wall of the receiving cavity; the third winding groove is located on the outer wall of the receiving cavity.
[0013] Furthermore, the cross-sectional length of the third winding groove along the first direction is less than or equal to the cross-sectional length of the first winding groove along the first direction; the cross-sectional length of the third winding groove along the first direction is less than or equal to the cross-sectional length of the second winding groove along the first direction.
[0014] Furthermore, the cross-sectional length of the third winding groove along the second direction is less than or equal to the cross-sectional length of the second winding groove along the second direction; the cross-sectional width of the third winding groove along the second direction is less than or equal to the cross-sectional length of the second winding groove along the second direction.
[0015] Furthermore, the first baffle, the second baffle, and the third winding groove are respectively movably wound around the outer wall of the receiving cavity.
[0016] Furthermore, the first baffle and the second baffle are hinged together by a connector.
[0017] Furthermore, the primary winding is spaced apart from the first baffle and the second baffle, respectively;
[0018] The first secondary winding and the first baffle, and the second secondary winding and the second baffle are respectively arranged at intervals.
[0019] Furthermore, an upper cover plate is provided above the second winding groove, and protrusions are provided at both ends of the upper cover plate.
[0020] Furthermore, a base is provided below the first winding groove, and the base is provided with multiple lead wire grooves.
[0021] The beneficial effects of this application are:
[0022] This application uses a sandwich winding method to wind the primary and secondary windings. The primary winding is located in the middle third winding slot, and the secondary windings are located in the first and second winding slots on both sides. This allows the magnetic field generated by the primary winding to be fully utilized, reducing flux linkage peak and hysteresis loss. By sliding the baffle to adjust the position of the first and second winding slots, the relative distance between the primary and secondary windings can be flexibly changed to control the leakage inductance and obtain the required leakage inductance, thereby avoiding the limitations caused by a fixed coupling degree.
[0023] In other words, while having the advantage of low hysteresis loss of sandwich winding, this application has a relatively larger leakage inductance; and by adjusting the position of the sliding baffle in the winding slot, the required leakage inductance can be obtained, making it suitable for magnetically integrated LLC transformers. Attached Figure Description
[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 This is a structural diagram of a sandwich-wound LLC transformer with adjustable leakage inductance.
[0026] Figure 2 This is a simplified structural diagram of a sandwich-wound LLC transformer with adjustable leakage inductance.
[0027] Explanation of reference numerals in the attached figures:
[0028] 1. Skeleton; 2. Winding slot; 21. First winding slot; 22. Second winding slot; 3. Baffle; 31. First baffle; 32. Second baffle; 33. Third winding slot; 34. Connector; 4. Receiving cavity; 5. Top cover plate; 51. Protrusion; 6. Base; 61. Lead wire slot; 7. Primary winding; 8. Secondary winding; 81. First secondary winding; 82. Second secondary winding;
[0029] X-axis: First direction; Y-axis: Second direction. Detailed Implementation
[0030] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, 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, 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 application.
[0031] like Figure 1 and Figure 2 As shown, this application provides a sandwich-wound LLC transformer with adjustable leakage inductance, including a frame 1, a winding slot 2, a coil winding, and a baffle 3; the frame 1 has a through-hole accommodating cavity 4; a magnetic core is inserted into the accommodating cavity 4; the winding slot 2 is wound around the outer wall of the accommodating cavity 4; the coil winding is wound around the winding slot 2; the baffle 3 is movably wound around the winding slot 2 to divide the winding slot 2 into a first winding slot 21 and a second winding slot 22; the baffle 3 has a third winding slot 33, the third winding... The wire slot 33 is located between the first winding slot 21 and the second winding slot 22; wherein, the coil winding includes a primary winding 7 and a secondary winding 8; the primary winding 7 is wound in the third winding slot 33; the secondary winding 8 is wound in the first winding slot 21 and the second winding slot 22 respectively; the secondary winding 8 and the primary winding 7 are arranged in a sandwich shape along the vertical direction of the magnetic core, so that the magnetic field generated by the primary winding 7 can be utilized more effectively, thereby reducing the flux linkage peak and hysteresis loss. In addition, by closely arranging the primary winding 7 and the secondary winding 8 on the same frame 1 and using the baffle 3 to achieve flexible adjustment, not only is the structure simplified, but the overall size is also reduced, and the power density is improved.
[0032] This application employs a sandwich winding method to wind the primary winding 7 and the secondary winding 8. The primary winding 7 is located in the middle third winding slot 33, while the secondary winding 8 is located in the first winding slot 21 and the second winding slot 22 on both sides. This allows the magnetic field generated by the primary winding 7 to be fully utilized, reducing flux linkage peaks and hysteresis losses. By adjusting the position of the sliding baffle 3 in the first and second winding slots 21 and 22, the relative distance between the primary winding 7 and the secondary winding 8 can be flexibly changed to control the leakage inductance and obtain the desired leakage inductance. This avoids the limitations imposed by the fixed coupling degree in traditional transformers, enabling the transformer to better adapt to different working environments and requirements. While possessing the advantage of low hysteresis loss from the sandwich winding method, this application also offers a relatively larger leakage inductance. Furthermore, by adjusting the position of the sliding baffle 3 in the winding slots, the desired leakage inductance can be obtained. This method is applicable to magnetically integrated LLC transformers.
[0033] In a preferred embodiment, the secondary winding 8 includes a first secondary winding 81 and a second secondary winding 82. The first secondary winding 81 is wound in the first winding slot 21, and the second secondary winding 82 is wound in the second winding slot 22. The first secondary winding 81 and the second secondary winding 82 are arranged at intervals along the vertical direction of the magnetic core. Specifically, by dividing the secondary winding 8 into a first secondary winding 81 and a second secondary winding 82, and arranging them at intervals along the vertical direction of the magnetic core, forming a sandwich-like arrangement of the secondary winding 8 and the primary winding 7, the magnetic field generated by the primary winding 7 can be more evenly induced by the secondary windings 8 on both sides, thereby improving the utilization rate of the magnetic field and the energy transmission efficiency, and thus reducing the flux linkage peak and hysteresis loss. In addition, the spaced secondary windings 8 provide more space for heat dissipation, which is beneficial for heat conduction and dissipation, effectively reducing the temperature rise of the winding, improving the heat dissipation performance of the transformer, and extending its service life.
[0034] In a preferred embodiment, the baffle member 3 further includes at least a first baffle 31 and a second baffle 32; the first baffle 31 is connected to the second baffle 32; a third winding groove 33 is recessed on the side wall between the first baffle 31 and the second baffle 32 away from the outer wall of the receiving cavity 4; the third winding groove 33 is located on the outer wall of the receiving cavity 4. Further, when the first baffle 31 and the second baffle 32 are an integral baffle member 3, a groove extending through to the outer wall of the receiving cavity 4 is formed on the baffle member 3 to create the third winding groove 33. Therefore, the projected width of the third winding groove 33 along the magnetic core direction is fixed and is not affected by the sliding position of the baffle member 3 in the winding groove. In this case, the projected width of the third winding groove 33 remains constant even when the baffle member 3 slides up and down along the magnetic core direction. Meanwhile, the projected width of the first winding slot 21 may be greater or less than the projected width of the second winding slot 22. This depends on adjusting the position of the baffle 3 to change the relative distance between the primary winding 7 and the secondary winding 8, thereby adjusting their inductance and obtaining the required leakage inductance.
[0035] In a preferred embodiment, the cross-sectional length of the third winding slot 33 along the first direction is less than or equal to the cross-sectional length of the first winding slot 21 along the first direction; the cross-sectional length of the third winding slot 33 along the first direction is less than or equal to the cross-sectional length of the second winding slot 22 along the first direction. This design, with its difference in X-axis cross-sectional length between the third winding slot 33 and the first and second winding slots 21 and 22, results in an asymmetrical stacking structure between the primary winding 7 and the secondary winding 8. This asymmetrical stacking not only retains the advantage of low hysteresis loss inherent in sandwich winding but also, due to its structural uniqueness, results in relatively large leakage inductance, thereby effectively controlling leakage inductance and ultimately improving the overall performance of the transformer.
[0036] In a preferred embodiment, the cross-sectional length of the third winding slot 33 along the second direction is less than or equal to the cross-sectional length of the second winding slot 22 along the second direction; the cross-sectional width of the third winding slot 33 along the second direction is less than or equal to the cross-sectional length of the second winding slot 22 along the second direction. This design, with its difference in Y-axis cross-sectional length between the third winding slot 33 and the first and second winding slots 21 and 22, results in an asymmetrical stacking structure between the primary winding 7 and the secondary winding 8. This asymmetrical stacking not only retains the advantage of low hysteresis loss inherent in sandwich winding but also, due to its structural uniqueness, results in relatively large leakage inductance, thus effectively controlling leakage inductance.
[0037] In a preferred embodiment, the first baffle 31, the second baffle 32, and the third winding groove 33 are movably wound around the outer wall of the receiving cavity 4. Specifically, the baffle 3, sliding on the outer wall of the receiving cavity 4, separates the winding grooves and maintains a stable working state. The first baffle 31, the second baffle 32, and the third winding groove 33 divide the winding grooves into a first winding groove 21 and a second winding groove 22 with different widths. This adjusts the relative distance between the primary winding 7 and the secondary winding, which are respectively wound around the first winding groove 21 and the second winding groove 22, thereby adjusting their inductance and obtaining the desired leakage inductance.
[0038] In a preferred embodiment, the first baffle 31 and the second baffle 32 are hinged together by a connector 34. Further, the baffle component 3 may also include a first baffle 31, a second baffle 32, and a connector; both ends of the connector 34 are respectively connected to the first baffle 31 and the second baffle 32; the connector 34 is disposed on the outer wall of the receiving cavity 4; the first baffle 31 is disposed above the first winding groove 21 and located on the outer wall of the receiving cavity 4; the second baffle 32 is disposed below the second winding groove 22 and located on the outer wall of the receiving cavity 4; wherein the first baffle 31, the second baffle 32, and the connector 34 together form the third winding groove 33. Therefore, the projected width between the first baffle 31 and the second baffle 32 along the magnetic core direction can be adjusted using the connector 34. In other words, the projected width of the third winding slot 33 along the magnetic core direction can be adjusted as needed. At this time, the projected widths of the third winding slot 33, the first winding slot 21, and the second winding slot 22 are uncertain and can be adjusted according to actual requirements. However, the relative distance between the primary winding 7 and the secondary winding 8 can still be changed by adjusting the position of the baffle 3, thereby adjusting the inductance of the secondary winding 8 and the primary winding 7 to obtain the required leakage inductance.
[0039] In a preferred embodiment, the primary winding 7 is spaced apart from the first baffle 31 and the second baffle 32, respectively; the first secondary winding 81 is spaced apart from the first baffle 31, and the second secondary winding 82 is spaced apart from the second baffle 32, respectively. Further, the first baffle 31 and the second baffle 32 physically separate the primary winding 7 and the secondary winding, creating a certain gap between them. This reduces the flux superposition effect between the primary and secondary windings, lowers the accumulated flux peak, reduces flux leakage, and improves coupling efficiency. Furthermore, the spacing between the components improves the transformer's heat dissipation performance, significantly reducing coil temperature rise and thus increasing the maximum power that can be transmitted.
[0040] In a preferred embodiment, a top cover plate 5 is provided above the second winding groove 22. The top cover plate 5 has raised strip-like structures, i.e., raised strips 51, at both ends. This allows the top cover plate 5 to effectively cooperate and be used in combination with external inductors. This design not only enhances the stability of the inductor's mounting but also provides additional protection, ensuring the safety and reliability of the inductor during operation. Furthermore, the top cover plate may also help improve the distribution of the electromagnetic field, thereby optimizing the performance of the entire circuit.
[0041] As a preferred embodiment, a base 6 is provided below the first winding groove 21. The base 6 is provided with a plurality of lead wire grooves 61, which can ensure that the coil leads can be drawn out from the lead wire grooves 61 in an orderly and neat manner.
[0042] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.
[0043] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Since these modifications and variations fall within the scope of the claims and their equivalents, this application also intends to include these modifications and variations.
Claims
1. A sandwich-wound LLC transformer with adjustable leakage inductance, characterized by, Include: Skeleton (1), the skeleton (1) has through containing cavity (4); The containing cavity (4) is inserted with magnetic core; Wire slot (2), is wound in the outer wall of the containing cavity (4); Coil winding, is wound in the wire slot (2); Baffle piece (3), is movably wound in the wire slot (2), to divide the wire slot (2) into first wire slot (21) and second wire slot (22);The baffle piece (3) is equipped with third wire slot (33), and the third wire slot (33) is located between the first wire slot (21) and the second wire slot (22); Wherein, the coil winding includes primary winding (7) and secondary winding (8);The primary winding (7) is wound in the third wire slot (33);The secondary winding (8) is wound in the first wire slot (21) and the second wire slot (22) respectively;The secondary winding (8) and the primary winding (7) are arranged in sandwich type along the vertical direction of the magnetic core.
2. The adjustable leakage inductance sandwich winding LLC transformer of claim 1, wherein, The secondary winding (8) includes first secondary winding (81) and second secondary winding (82);The first secondary winding (81) is wound in the first wire slot (21);The second secondary winding (82) is wound in the second wire slot (22), and the first secondary winding (81) and the second secondary winding (82) are arranged in interval along the vertical direction of the magnetic core.
3. The adjustable leakage inductance sandwich winding LLC transformer of claim 2, wherein, The baffle piece (3) further includes at least first baffle (31) and second baffle (32);The first baffle (31) is connected to the second baffle (32);The sidewall of the first baffle (31) and the second baffle (32) away from the outer wall of the containing cavity (4) is concave with the third wire slot (33);The third wire slot (33) is located in the outer wall of the containing cavity (4).
4. The adjustable leakage inductance sandwich winding LLC transformer of claim 3, wherein, The cross-sectional length of the third wire slot (33) along the first direction is less than or equal to the cross-sectional length of the first wire slot (21) along the first direction;The cross-sectional length of the third wire slot (33) along the first direction is less than or equal to the cross-sectional length of the second wire slot (22) along the first direction.
5. The adjustable leakage inductance sandwich winding LLC transformer of claim 3, wherein, The cross-sectional length of the third wire slot (33) along the second direction is less than or equal to the cross-sectional length of the second wire slot (22) along the second direction;The cross-sectional width of the third wire slot (33) along the second direction is less than or equal to the cross-sectional length of the second wire slot (22) along the second direction.
6. The adjustable leakage inductance sandwich winding LLC transformer of claim 3, wherein, The first baffle (31), the second baffle (32) and the third wire slot (33) are movably wound in the outer wall of the containing cavity (4) respectively.
7. The adjustable leakage inductance sandwich winding LLC transformer of claim 3, wherein, The first baffle (31) and the second baffle (32) are hingedly connected by connecting piece (34).
8. The adjustable leakage inductance sandwich winding LLC transformer of claim 3, wherein, The primary winding (7) is arranged in interval with the first baffle (31) and the second baffle (32) respectively; The first secondary winding (81) and the second baffle (32) are arranged in interval with the first baffle (31) and the second secondary winding (82) respectively.
9. The adjustable leakage inductance sandwich winding LLC transformer of claim 1, wherein, The upper side of the second wire slot (22) is provided with upper cover plate (5), and the both ends of the upper cover plate (5) are respectively provided with convex strip (51).
10. The adjustable leakage inductance sandwich winding LLC transformer of claim 1, wherein, A base (6) is arranged below the first wire slot (21), and the base (6) is provided with a plurality of lead slots (61).