Planar transformers

Abstract

The present disclosure provides a planar transformer, relating to the field of transformer technology. The planar transformer comprises a primary coil and a secondary coil, at least one of which comprises a winding coil. The winding coil is wound around a metal conductor coated with a corona-resistant polyimide fluororesin sintered film. The polyimide fluororesin sintered film is securely fixed to the outer surface of the metal conductor by sintering. Due to the excellent insulation properties of the polyimide fluororesin sintered film and the method of fixing the polyimide fluororesin sintered film, the planar transformer fabricated from the winding coil exhibits excellent insulation performance, good corona resistance, and a long service life.

Description

Technical Field

[0001] The present disclosure relates to the technical field of transformers, and in particular to a planar transformer. Background Art

[0002] Planar transformers feature a flat core, primary coil, and secondary coil, all with a low profile and a compact design. Both coils are wound from metal wire, coated with a cured insulating varnish that provides insulation and corona protection.

[0003] Existing insulating varnish materials have poor insulation performance and corona resistance. They are easily oxidized by materials such as oxygen atoms, ions and nitrogen oxides generated by corona discharge, losing their original performance characteristics. At the same time, under the action of ozone generated by corona discharge, the insulating varnish layer will locally heat up, causing the polymer chains of the insulating varnish material to break down, resulting in the insulating varnish layer becoming brittle and even cracking.

[0004] Therefore, existing planar transformers have disadvantages such as poor insulation performance, poor corona resistance, and short service life. Summary of the Invention

[0005] The present disclosure provides a planar transformer to solve the defects in the related art.

[0006] A first aspect of the present disclosure provides a planar transformer, comprising: a primary coil and a secondary coil;

[0007] At least one of the primary coil and the secondary coil includes a winding coil formed by winding a metal wire whose outer surface is coated with a corona-resistant polyimide fluororesin sintered film.

[0008] Optionally, the primary coil includes the winding coil and a PCB coil, and the winding coil and the PCB coil are connected in series.

[0009] Optionally, the winding coil includes a first winding coil and a second winding coil, the first winding coil and the second winding coil are respectively arranged on both sides of the PCB coil, and the three are connected in series.

[0010] Optionally, the secondary coil includes at least one coil group consisting of two single-turn winding coils connected in series.

[0011] Optionally, the secondary coil includes three groups of coil groups, each of the coil groups is connected in parallel, the first winding coil, the second winding coil, the PCB coil and each of the coil groups are stacked in layers, and the three groups of coil groups are separated one by one by the first winding coil, the second winding coil and the PCB coil.

[0012] Optionally, the planar transformer further includes a limiting member and a lead, the lead is connected to the terminal of the primary coil, and the limiting member is used to limit the relative position of the lead and the terminal.

[0013] Optionally, the limiting member includes a flat plate provided with a limiting hole, the limiting hole is directly opposite to the wiring terminal, and the lead wire is inserted into the limiting hole and connected to the wiring terminal.

[0014] Optionally, the plate further includes limiting ribs, and the limiting ribs are inserted into the gaps between the terminals of the secondary coil to limit the distance between the terminals of the secondary coil.

[0015] Optionally, the limiting member is made of insulating material.

[0016] Optionally, the secondary coil includes a U-shaped connecting piece, the head end and / or tail end of the secondary coil is inserted into the hollow of the connecting piece, and the connecting piece is used to connect to an external terminal.

[0017] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

[0018] The planar transformer provided by the present disclosure has at least the following beneficial effects:

[0019] The planar transformer provided in the embodiment of the present disclosure includes a primary coil and a secondary coil, at least one of the primary coil and the secondary coil includes a winding coil, which is wound by a metal wire coated with a corona-resistant polyimide fluororesin sintered film on the outer surface. The polyimide fluororesin sintered film is firmly fixed to the outer surface of the metal wire by sintering. Based on the good insulation performance of the polyimide fluororesin sintered film and the fixing method of the polyimide fluororesin sintered film, the planar transformer made of the winding coil has the characteristics of good insulation performance, good corona resistance, and long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of a planar transformer according to an exemplary embodiment;

[0021] Figure 2 yes Figure 1 The structural exploded diagram of the planar transformer is shown.

[0022] Wherein each mark in the accompanying drawings means:

[0023] 1. First winding coil; 11. First planar spiral coil; 12. Second planar spiral coil;

[0024] 2. Second winding coil; 3. PCB coil; 4. Coil assembly;

[0025] 41. Terminal; 5. Primary lead; 6. Limiter;

[0026] 61. Flat plate; 7. Limiting ribs; 8. Connectors;

[0027] 9. Rivet pin; A. End point; B. End point;

[0028] C, terminal; D, endpoint; E, connection terminal;

[0029] a. Limiting hole; b. Fixing hole; DETAILED DESCRIPTION

[0030] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0031] The terminology used in this application is for the purpose of describing specific embodiments only and is not intended to limit this application. Unless otherwise defined, technical or scientific terms used in this application should have the same ordinary meaning as understood by a person of ordinary skill in the art to which this invention belongs. The terms "first," "second," and similar terms used in this specification and claims do not denote any order, quantity, or importance, but are simply used to distinguish one component from another. Similarly, the terms "a" or "an" and similar terms do not denote a limitation of quantity, but rather denote the presence of at least one. The terms "plurality" or "several" refer to two or more. Unless otherwise indicated, the terms "front," "rear," "lower," and / or "upper," "top," and "bottom" are used for convenience only and are not intended to limit a position or spatial orientation. The terms "include," "comprising," and similar terms mean that the elements or items preceding the term "include" or "comprising" include the elements or items listed after the term and their equivalents, and do not exclude other elements or items. The terms "connected," "connected," and similar terms are not limited to physical or mechanical connections and may include electrical connections, whether direct or indirect.

[0032] Please refer to Figures 1 to 2An embodiment of the present disclosure provides a planar transformer, which includes a primary coil and a secondary coil, wherein at least one of the primary coil and the secondary coil includes a winding coil, which is wound by a metal wire whose outer surface is coated with a corona-resistant polyimide fluororesin sintered film.

[0033] Since the polyimide fluororesin material in the polyimide fluororesin sintered film has good insulation properties, and the polyimide fluororesin sintered film is reliably fixed to the surface of the metal wire through sintering, based on the material properties and fixing method of the polyimide fluororesin sintered film, the planar transformer made of the winding coil has the characteristics of good insulation performance, good corona resistance, and long service life.

[0034] While meeting the product safety requirements (i.e., safety regulations) in product certification, the planar transformer made from this winding coil has an insulation performance of 3750V / AC to 6000V / AC, an arc resistance of level 15, and a corona resistance of 20kV / mm, 50Hz / 60Hz.

[0035] In an optional embodiment, the primary coil may include a winding coil and a PCB coil, wherein the winding coil and the PCB coil are connected in series. The PCB coil is a coil made by etching metal lines on a PCB board. The PCB coil has a plate-like structure and can support and secure the winding coils located on one or both sides of the PCB coil, thereby maintaining the structural stability of each winding coil in the planar transformer.

[0036] The PCB coil's PCB is equipped with terminals for connecting to the winding coils. By connecting the primary leads to these terminals, the PCB coil can be connected to each winding coil. Furthermore, the PCB coil can serve as a supplementary coil, supplementing the number of turns in the winding coil to meet the total number of turns in the primary coil design required by the planar transformer. For example, if the number of turns in the winding coil is even, the PCB coil can be added to increase the number of turns in the winding coil, making the total number of turns in the primary coil of the planar transformer an odd number.

[0037] For example, please refer to Figure 1 and Figure 2 The planar transformer includes a first winding coil 1, a second winding coil 2, and a PCB coil 3. The PCB coil 3 is located between the first and second winding coils 1 and 2. These three coils are connected in series and together form the primary coil. The metal conductors of the first and second winding coils 1 and 2 are both coated with a polyimide fluororesin sintered film.

[0038] The PCB coil 3 is provided with endpoints A, B, C, and D. One end of the first winding coil 1 is connected to endpoint A of the PCB coil 3, and the other end of the first winding coil 1 is connected to endpoint B of the PCB coil 3. One end of the second winding coil 2 is connected to endpoint C of the PCB coil 3, and the other end of the second winding coil 2 is connected to endpoint D of the PCB coil 3, thereby achieving a series connection between the first winding coil 1, the PCB coil 3, and the second winding coil 2.

[0039] By providing the PCB coil 3 , the first winding coil 1 and the second winding coil 2 can be fixed to the PCB coil 3 respectively, and the PCB coil 3 supports and fixes the first winding coil 1 and the second winding coil 2 located on both sides.

[0040] In one example, the first winding coil 1 includes two layers of planar spiral coils wound along a spiral line, specifically including a first planar spiral coil 11 and a second planar spiral coil 12. The head ends of the first planar spiral coil 11 and the second planar spiral coil 12 are connected and have opposite rotation directions, and the number of turns of the first planar spiral coil 11 and the second planar spiral coil 12 are equal.

[0041] In the above description, the first winding coil 1, comprising two layers of planar spiral coils, can maintain a constant number of turns while maintaining a small thickness and volume, facilitating the flattening of planar transformers and planar inductors. Furthermore, it is readily understood that the required current or voltage carried by the first winding coil 1 can be met by increasing the number of turns of the planar spiral coils.

[0042] In this example, the gap between any two adjacent turns in the first planar spiral coil 11 is equal, and this gap is defined as the first gap. The gap between any two adjacent turns in the second planar spiral coil 12 is equal, and this gap is defined as the second gap. The first gap is equal to the second gap.

[0043] The structure of the second winding coil 2 can be the same as that of the first winding coil 1 , which makes the first winding coil 1 and the second winding coil 2 structurally symmetrical, and is beneficial to structural stability.

[0044] The cross-section of the planar spiral coil can be rectangular. This configuration allows both the first winding coil 1 and the second winding coil 2 to have a larger surface area. Based on the principle of the adjacent edge effect of current, this reduces the temperature rise of the winding coils and reduces heat generation. This reduces the heat generation of the planar transformer equipped with this planar spiral coil. Of course, the cross-sectional shape of the planar spiral coil is not limited to a rectangle and can be selected based on actual needs.

[0045] Please continue to refer to Figure 1 and Figure 2In an optional embodiment, the secondary coil of the planar transformer may include at least one coil group 4 consisting of two single-turn winding coils connected in series. That is, in a planar transformer, all secondary coils may be configured as coil groups 4. Alternatively, some secondary coils may be configured as coil groups 4, while others may have other configurations.

[0046] In this example, the secondary coil includes three coil groups 4 connected in parallel. Each coil group 4 is composed of two single-turn winding coils connected in series. The coil groups 4 are connected in parallel. Single-turn winding coils can reduce the length of the magnetic material, reduce magnetic resistance, and improve efficiency.

[0047] Furthermore, the first winding coil 1, the second winding coil 2, the PCB coil 3, and the coil assemblies 4 are stacked in layers, with the three coil assemblies 4 separated from each other by the first winding coil 1, the second winding coil 2, and the PCB coil 3. This arrangement allows for alternating primary and secondary coils, coupling the primary and secondary coils to reduce leakage inductance and losses in the planar transformer.

[0048] To ensure a reliable electrical connection, in an optional embodiment, the planar transformer further includes a stopper 6 and a lead 5 connected to the primary coil terminal. The stopper 6 is used to restrict the relative position of the lead 5 and the terminal. The stopper 6 ensures a stable relative position between the lead 5 and the terminal, preventing damage caused by bending of the lead 5 relative to the terminal, thereby extending the service life of the planar transformer.

[0049] For example, Figure 1 and Figure 2 In the embodiment, the PCB coil 3 is further provided with two terminals E. The retaining member 6 includes a flat plate 61 having a retaining hole a. One retaining hole a is aligned with one terminal E. The primary lead 5 is inserted into the retaining hole a and connected to the terminal E. The arrangement of the flat plate 61 with the retaining hole a ensures a stable position between the primary lead 5 and the terminal E, preventing the primary lead 5 from bending relative to the terminal E and causing damage, thereby ensuring the structural stability of the planar transformer.

[0050] Figure 1 and Figure 2 In the illustrated planar transformer, plate 61 is provided with limiting ribs 7. These ribs are inserted into the gaps between the secondary coil terminals to limit the distance between them and prevent them from shifting. Limiting ribs 7 can be made of an insulating material to ensure insulation between the coil terminals.

[0051] In an optional embodiment, the secondary coil may further include a U-shaped connecting member 8 , and the head end and / or tail end of the secondary coil is inserted into the hollow portion of the connecting member 8 .

[0052] The connector 8 is used to connect to the external terminal. At the same time, the U-shaped connector 8 plays a safety role for the head end and / or tail end of the secondary coil, preventing the edge of the coil assembly 4 from being damaged due to collision or extrusion.

[0053] Each coil assembly 4 includes three terminals 41, each located in the hollow portion of a connector 8. Adjacent connectors 8 contact each other along the stacking direction of the coil assemblies 4. The arrangement of multiple connectors 8 prevents displacement of the three coil assemblies 4 along the stacking direction, ensuring structural stability.

[0054] Each terminal 41 is provided with a connection hole, and each U-shaped arm of the connector 8 is provided with two oppositely arranged fixing holes b. The connection hole on each terminal 41 and the two fixing holes b on the connector 8 covering the terminal 41 are coaxially arranged.

[0055] The planar transformer also includes three fixing members, each of which is a rivet pin 9. Each rivet pin 9 extends into a coaxial connection hole and a fixing hole b. The three coaxial connectors 8 are relatively fixed to the three coaxial terminals 41 by connecting a rivet pin 9. In addition to rivet pins 9, the fixing members can also be other adaptive structures, such as bolts. Based on the provision of fixing members (such as rivet pins 9), the connection and fixation of the connectors 8 and the parallel coil groups 4 are achieved, ensuring the stability of the overall structure of the planar transformer.

[0056] Connectors are not limited to Figure 1 and Figure 2 The U-shaped structure shown in the figure may also adopt other adaptive structures. For example, the connecting member includes two independent limiting plates, each of which has a fixing hole, and the two limiting plates are arranged on both sides of a terminal in the coil assembly 4.

[0057] Figure 1 and Figure 2 The planar transformer shown also includes three external terminals (not shown), which are connected one-to-one with three rivet pins 9. The external terminals can be sheet-like structures, each with a fixing hole at each end. A rivet pin 9 extends into a fixing hole of an external terminal to connect the rivet pin 9 to the external terminal. The other fixing hole of the external terminal is used to connect to the terminal of an external electrical device, thereby achieving an electrical connection between the planar transformer and the external electrical device.

[0058] Other embodiments of the present disclosure will readily occur to those skilled in the art after considering the specification and practicing the disclosure herein. This disclosure is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the present disclosure being indicated by the following claims.

Claims

1. A planar transformer, characterized in that: include: A primary coil and a secondary coil; at least one of the primary coil and the secondary coil comprises a winding coil, the winding coil being wound by a metal wire having an outer surface coated with a corona-resistant polyimide fluororesin sintered film; The primary coil includes the winding coil and the PCB coil, and the winding coil includes a first winding coil and a second winding coil; The PCB coil is provided with an endpoint A, an endpoint B, an endpoint C, and an endpoint D; One end of the first winding coil is connected to end point A of the PCB coil, the other end of the first winding coil is connected to end point B of the PCB coil, one end of the second winding coil is connected to end point C of the PCB coil, and the other end of the second winding coil is connected to end point D of the PCB coil; The PCB coil is further provided with two terminals E; the planar transformer further includes a limiter and a lead, the lead being connected to the terminal E of the PCB coil, and the limiter being used to limit the relative position of the lead and the terminal E; The limiting member includes a flat plate with a limiting hole, the limiting hole is directly opposite to the terminal E, the lead is inserted into the limiting hole and connected to the terminal E; The secondary coil includes a U-shaped connecting piece, the head end and / or tail end of the secondary coil is inserted into the hollow of the connecting piece, and the connecting piece is used to connect to an external terminal.

2. The planar transformer according to claim 1, wherein: The first winding coil and the second winding coil are respectively arranged on both sides of the PCB coil, and the three are connected in series.

3. The planar transformer according to claim 2, wherein: The secondary coil includes at least one coil group formed by two single-turn winding coils connected in series.

4. The planar transformer according to claim 3, wherein: The secondary coil includes three groups of coil groups, each of which is connected in parallel. The first winding coil, the second winding coil, the PCB coil, and each of the coil groups are stacked in layers. The three groups of coil groups are separated one by one by the first winding coil, the second winding coil, and the PCB coil.

5. The planar transformer according to claim 1, wherein: The plate further includes limiting ribs, which are inserted into the gaps between the terminals of the secondary coils to limit the distance between the terminals of the secondary coils.

6. The planar transformer according to claim 1, wherein: The limiting component is made of insulating material.

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