A frameless flat high-frequency transformer

Abstract

This utility model relates to the field of high-frequency power electronics technology and discloses a frameless planar high-frequency transformer, including a PCB board. The outer surface of the PCB board has positioning grooves and clearance holes. A ceramic thick film is disposed on the outer surface of the PCB board, and silver wires are disposed on the outer surface of the ceramic thick film. The silver wires are fixedly connected to the PCB board by solder feet. An insulating film is attached to the surfaces of the ceramic thick film and the silver wires. A magnetic core is disposed on the surface of the PCB board. A shielding cover is fixedly disposed on the outer surface of the PCB board, and contact copper strips are snapped onto the inner surface of the shielding cover. This frameless planar high-frequency transformer, with its ceramic thick film and silver wire design, can reduce the skin effect at high frequencies, optimize inductance, and improve energy transmission efficiency under high-frequency conditions. Simultaneously, the ceramic thick film itself has good thermal conductivity, which, combined with the shielding cover and contact copper strips, forms an effective heat dissipation path, accelerating heat dissipation.

Description

Technical Field

[0001] This utility model relates to the field of high-frequency power electronics technology, specifically to a frameless flat-plate high-frequency transformer. Background Technology

[0002] In the field of power electronics, high-frequency transformers are key components, and their performance directly affects the efficiency and reliability of the entire system. Traditional high-frequency transformers mostly adopt a wound structure, which has revealed many drawbacks in long-term application practice. The high leakage inductance of the wound structure causes some energy to be lost in the form of leakage flux during energy transmission, reducing the transmission efficiency of the transformer. The high distributed capacitance can easily cause signal interference, affecting the stability of the circuit. The poor heat dissipation means that the heat generated by the windings is difficult to dissipate effectively under high current conditions, causing the transformer temperature to rise, which in turn affects its electrical performance and may even lead to the aging of insulation materials, shortening the service life of the transformer. In addition, the manual winding method results in low product consistency, making it difficult to meet the requirements of product quality stability for large-scale production.

[0003] To improve high-frequency performance, frameless planar transformers have emerged. However, existing frameless planar transformers still face a series of problems that urgently need to be solved. In terms of heat dissipation, the thermal conductivity of ordinary PCB windings or thin-film windings is insufficient. When the transformer is under high current conditions, the large amount of heat generated cannot be dissipated in time, resulting in excessively high internal temperatures, which seriously affects the reliability of the transformer and limits its application in high-power scenarios. From the perspective of the skin effect, under high-frequency conditions, the current concentrates on the conductor surface, resulting in low current density inside the conductor. This significantly reduces the utilization rate of the conductor cross-sectional area and limits the current density. This not only increases the effective resistance of the conductor, leading to increased energy loss, but also limits the current carrying capacity of the transformer. In terms of core window utilization, the traditional E-type core structure, due to its shape and structural characteristics, does not make reasonable use of space and cannot fully utilize the efficiency of the core, affecting the improvement of the transformer's power density. In the assembly process, the core fixing method is unstable. When subjected to external forces such as vibration, the core is prone to displacement, affecting the transformer's performance. At the same time, the heat dissipation path has not been optimized, further exacerbating the heat dissipation problem.

[0004] In summary, developing a frameless planar high-frequency transformer that can effectively solve the above problems and has good heat dissipation performance, high conductor cross-sectional area utilization, high core window utilization, and stable assembly structure is of great practical significance. Utility Model Content

[0005] The purpose of this invention is to provide a frameless planar high-frequency transformer to solve the problems mentioned in the background art, such as limited heat dissipation, significant skin effect, low core window utilization, and complex assembly.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a frameless flat high-frequency transformer, comprising a PCB board, wherein the outer surface of the PCB board is provided with a positioning groove and a clearance hole, a ceramic thick film is provided on the outer surface of the PCB board, and a silver wire is provided on the outer surface of the ceramic thick film, and the silver wire is fixedly connected to the PCB board by solder feet, an insulating film is attached to the surface of the ceramic thick film and the silver wire, and a magnetic core is provided on the surface of the PCB board, wherein recessed steps are provided at both ends of the magnetic core;

[0007] A shielding cover is fixedly installed on the outer surface of the PCB board, and a contact copper strip is snapped onto the inner surface of the shielding cover.

[0008] Preferably, the positioning groove is a V-shaped design, and the openings of the two V-shaped positioning grooves face each other at one end, and the openings of the two V-shaped positioning grooves face the clearance hole at one end, and the two positioning grooves are symmetrical about the center of the clearance hole.

[0009] By adopting the above technical solution, the V-shaped positioning groove and the sinking steps at both ends of the magnetic core form a precise engagement. The symmetrical structure is used to achieve stable positioning of the magnetic core, avoid displacement deviation during assembly, and optimize the installation path of the magnetic core, which facilitates automated assembly.

[0010] Preferably, the silver conductor is applied to the surface of the ceramic thick film using a printing process, and the vertical projection of the insulating film completely covers the silver conductor.

[0011] By adopting the above technical solution, the linewidth and spacing of the silver conductors can be precisely controlled by the printing process, reducing the skin effect loss at high frequencies. At the same time, the high thermal conductivity of the ceramic thick film can quickly dissipate the heat of the silver conductors. The full-coverage design of the insulating film can isolate the electrical path without affecting the heat dissipation path, ensuring electrical safety and heat dissipation efficiency under high-frequency operating conditions.

[0012] Preferably, the outer surface of the middle section of the magnetic core is cylindrical, and the outer diameter of the cylindrical end of the middle section of the magnetic core is smaller than the inner diameter of the clearance hole.

[0013] By adopting the above technical solution, the cylindrical middle section design can reduce the contact area between the magnetic core and the PCB board, reduce magnetic resistance, optimize the magnetic circuit closure efficiency, and the structure with an outer diameter smaller than the inner diameter of the clearance hole can avoid hard friction between the magnetic core and the PCB board, while providing buffer space for the installation of the magnetic core and ensuring the compatibility between the magnetic core and the PCB board.

[0014] Preferably, the recessed steps at both ends of the magnetic core are V-shaped, and the magnetic core is engaged with the positioning groove through the recessed steps at both ends. The two magnetic cores are designed to face each other, and the outer surfaces of the two magnetic cores facing each other are in contact.

[0015] By adopting the above technical solution, the engagement structure of the V-shaped recessed step and the positioning groove can form a mechanical limit, enhance the vibration resistance of the magnetic core, and the two magnetic cores can be attached to each other to shorten the magnetic circuit length, reduce magnetic leakage, optimize the utilization rate of the magnetic core window space, and improve the power density of the transformer.

[0016] Preferably, the middle section of the contact copper strip has a downward-curved arc design, and the outer surface of the middle section of the contact copper strip is in contact with the outer surface of the magnetic core.

[0017] By adopting the above technical solution, the arc-shaped middle section design can closely fit the outer surface of the magnetic core, forming a heat dissipation path of "magnetic core → contact copper strip → shielding cover", which accelerates the conduction of heat loss from the magnetic core. Compared with the traditional solution, it can reduce the temperature rise by more than 30%. At the same time, the cooperation between the contact copper strip and the shielding cover can generate a clamping force on the magnetic core, further enhancing the structural stability and simplifying the assembly process.

[0018] Compared with the prior art, the beneficial effects of this utility model are: This frameless flat plate high-frequency transformer:

[0019] 1. The design of ceramic thick film combined with silver conductors can reduce the skin effect at high frequencies, optimize inductance, and improve energy transfer efficiency under high-frequency conditions. At the same time, the ceramic thick film itself has good thermal conductivity, which, combined with the shielding cover and contact copper strips, forms an effective heat dissipation path and accelerates heat dissipation.

[0020] 2. Enhanced structural stability: The recessed steps at both ends of the magnetic core engage with the positioning slots on the PCB board, and the magnetic core is effectively fixed by the pressing action of the shield and contact copper strips, enhancing its vibration resistance and ensuring stable operation of the transformer in harsh environments. At the same time, the improved magnetic core structure optimizes the spatial layout, increases the utilization rate of the magnetic core window, and helps to improve the power density of the transformer.

[0021] 3. The coil is made using ceramic thick film printing technology, which reduces manual winding errors and improves product consistency and reliability. The shielding cover can cover the magnetic core and coil, reducing magnetic leakage interference and EMI noise. The magnetic core engages with the positioning groove through a recessed step, and the shielding cover is installed in conjunction with the contact copper strip, which simplifies the assembly process and improves production efficiency. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the present invention;

[0023] Figure 2 This is a three-dimensional structural diagram of the cross-sectional view of the connection between the shielding cover and the contact copper strip of this utility model;

[0024] Figure 3 This is a three-dimensional structural diagram of the PCB board, magnetic core, and sunken step of this utility model in a disassembled state.

[0025] Figure 4 This is a three-dimensional structural diagram of the connection between the magnetic core and the sunken step of this utility model;

[0026] Figure 5 This is a three-dimensional structural diagram of the connection between the ceramic thick film, silver wire, and insulating film material of this utility model;

[0027] Figure 6 This is a three-dimensional structural diagram of the PCB board, positioning groove, and clearance hole connection of this utility model.

[0028] In the diagram: 1. PCB board; 2. Positioning groove; 3. Clearance hole; 4. Ceramic thick film; 5. Solder foot; 6. Silver conductor; 7. Insulating film; 8. Magnetic core; 9. Recessed step; 10. Shielding cover; 11. Contact copper strip. Detailed Implementation

[0029] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0030] Please see Figures 1-6 This utility model provides a technical solution: a frameless flat plate high-frequency transformer.

[0031] Example 1: This example discloses: PCB board 1, the outer surface of PCB board 1 is provided with positioning groove 2 and clearance hole 3, the outer surface of PCB board 1 is provided with ceramic thick film 4, and the outer surface of ceramic thick film 4 is provided with silver wire 6, and the silver wire 6 is fixedly connected to PCB board 1 by solder feet 5, the surface of ceramic thick film 4 and silver wire 6 is covered with insulating film 7, the surface of PCB board 1 is provided with magnetic core 8, and the two ends of magnetic core 8 are provided with recessed steps 9;

[0032] The positioning groove 2 is a V-shaped design, and the openings of the two V-shaped positioning grooves 2 are set facing each other, and the openings of the two V-shaped positioning grooves 2 are set towards the clearance hole 3. The two positioning grooves 2 are symmetrical about the center of the clearance hole 3.

[0033] The silver conductor 6 is set on the surface of the ceramic thick film 4 by printing process, and the vertical projection of the insulating film 7 completely covers the silver conductor 6.

[0034] The outer surface of the middle section of the magnetic core 8 is cylindrical, and the outer diameter of the cylindrical end of the middle section of the magnetic core 8 is smaller than the inner diameter of the relief hole 3.

[0035] The recessed steps 9 at both ends of the magnetic core 8 are V-shaped, and the magnetic core 8 is engaged with the positioning groove 2 through the recessed steps 9 at both ends. The two magnetic cores 8 are designed to face each other, and the outer surfaces of the two magnetic cores 8 facing each other are in contact.

[0036] With its high thermal conductivity (>20W / m・K), the ceramic thick film 4 quickly dissipates the heat generated by the silver wire 6. The silver wire 6 is embedded in the surface of the ceramic thick film 4. Its low resistivity can reduce the increase in impedance caused by the skin effect current concentration on the surface at high frequencies, thereby improving energy transfer efficiency. The vertical projection of the insulating film 7 completely covers the silver wire 6, isolating the electrical path, while not obstructing the heat dissipation path of the ceramic thick film 4.

[0037] The middle section of the magnetic core 8 is cylindrical, with an outer diameter smaller than the inner diameter of the clearance hole 3, which reduces the contact magnetic resistance between the magnetic core 8 and the PCB board 1. The V-shaped recessed steps 9 at both ends engage with the V-shaped positioning grooves 2 on the PCB board 1 to form a mechanical limit, preventing the magnetic core 8 from shifting during vibration. The two magnetic cores 8 are in close contact with each other, optimizing the closed magnetic circuit path, reducing magnetic leakage, improving the utilization rate of the window space of the magnetic core 8, and thus increasing the power density.

[0038] The printing process of ceramic thick film 4 replaces manual winding, and the line width and spacing of silver conductor 6 are precisely controlled through printing. The product parameter dispersion is <5%, which is suitable for automated mass production.

[0039] Example 2: This example discloses, based on Example 1, that a shielding cover 10 is fixedly provided on the outer surface of the PCB board 1, and a contact copper strip 11 is snapped onto the inner surface of the shielding cover 10;

[0040] The middle section of the contact copper strip 11 has a downward curved arc design, and the outer surface of the middle section of the contact copper strip 11 is in contact with the outer surface of the magnetic core 8.

[0041] The downward-curving arc structure in the middle section fits closely to the outer surface of the magnetic core 8, conducting the heat generated by the loss of the magnetic core 8 to the shield 10, forming a heat dissipation path of "magnetic core 8 → contact copper strip 11 → shield 10", which reduces the temperature rise by more than 30% compared with the traditional solution.

[0042] The shield 10 covers the magnetic core 8 and the coil, suppressing leakage flux diffusion, reducing EMI noise, and meeting the anti-interference requirements of high-frequency power supplies.

[0043] After the shielding cover 10 is installed, the contact copper strip 11 exerts a downward pressing force on the magnetic core 8. Combined with the engagement of the recessed step 9 and the positioning groove 2, the vibration resistance of the magnetic core 8 is enhanced, making it suitable for harsh environments such as vehicle-mounted applications. At the same time, the engagement structure of the shielding cover 10 and the contact copper strip 11 replaces traditional complex fasteners, improving production efficiency.

[0044] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A frameless flat high-frequency transformer, comprising a PCB board (1), the outer surface of the PCB board (1) is provided with a positioning groove (2) and a clearance hole (3), characterized in that: The outer surface of the PCB board (1) is provided with a ceramic thick film (4), and the outer surface of the ceramic thick film (4) is provided with a silver wire (6). The silver wire (6) is fixedly connected to the PCB board (1) by solder feet (5). The surfaces of the ceramic thick film (4) and the silver wire (6) are covered with an insulating film (7). The surface of the PCB board (1) is provided with a magnetic core (8), and the two ends of the magnetic core (8) are provided with recessed steps (9).

2. The frameless planar high-frequency transformer according to claim 1, characterized in that: The outer surface of the PCB board (1) is fixedly provided with a shield (10), and a contact copper strip (11) is engaged and installed on the inner surface of the shield (10).

3. The frameless planar high-frequency transformer according to claim 1, characterized in that: The positioning groove (2) is a V-shaped design, and the openings of the two V-shaped positioning grooves (2) are set facing each other, and the openings of the two V-shaped positioning grooves (2) are set towards the clearance hole (3). The two positioning grooves (2) are symmetrical about the center of the clearance hole (3).

4. A coreless planar high frequency transformer according to claim 1, characterized in that: The silver conductor (6) is set on the surface of the ceramic thick film (4) by printing process, and the vertical projection of the insulating film (7) completely covers the silver conductor (6).

5. A frameless planar high-frequency transformer according to claim 1, characterized in that: The outer surface of the middle section of the magnetic core (8) is cylindrical, and the outer diameter of the cylindrical end of the middle section of the magnetic core (8) is smaller than the inner diameter of the relief hole (3).

6. A coreless planar high frequency transformer according to claim 1, characterized in that: The sinking steps (9) at both ends of the magnetic core (8) are V-shaped, and the magnetic core (8) is engaged with the positioning groove (2) through the sinking steps (9) at both ends. The two magnetic cores (8) are designed to face each other, and the outer surfaces of the two magnetic cores (8) facing each other are in contact.

7. A coreless planar high frequency transformer according to claim 2, characterized in that: The middle section of the contact copper strip (11) is a downward curved arc design, and the outer surface of the middle section of the contact copper strip (11) is in contact with the outer surface of the magnetic core (8).

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