Equivalent loss construction model and interleaved winding analysis method of high-frequency planar transformer

Abstract

The present application relates to the equivalent loss construction model and the interleaved winding analysis method of high-frequency planar transformer, relates to the high-frequency electrical engineering technical field, including magnetic core, winding and PCB board; the present application establishes the equivalent loss model and the circuit of high-frequency planar transformer through the physical structure characteristics of planar transformer, is used to verify the theoretical correctness that the interleaved winding analysis method can effectively reduce the peak magnetic flux density of transformer, the AC resistance value in winding and the mixed leakage inductance value, and the interleaved half-turn winding arrangement method helps to simplify the complexity of transformer insulation design and reduce the creepage distance and gap distance, simultaneously, the interleaved winding arrangement method reduces the number of turns of planar transformer through the new winding formed in space, thereby reducing the leakage inductance value of planar transformer, and increasing excitation inductance, thereby reducing leakage flux area and increasing excitation inductance flux area.

Description

Technical Field

[0001] This invention relates to the field of high-frequency electrical engineering technology, and in particular to the equivalent loss construction model of high-frequency planar transformers and the method for analyzing interleaved windings. Background Technology

[0002] Power losses in high-frequency converters are distributed across switching devices, high-frequency transformers, diodes, and stray parameters in the circuitry. These distributed power losses require a comprehensive loss model for analysis. Therefore, an effective power loss model is crucial for optimizing system distributed losses and improving output efficiency. In the optimized design of high-frequency transformers, leakage inductance (existing between turns and layers of the coil, resulting in leakage flux) and distributed capacitance (existing between turns and layers of each winding, between different windings, and between windings and the shielding layer) need to be minimized as much as possible. During the switching transients of high-frequency devices, these parasitic parameters, due to leakage inductance and distributed capacitance, generate voltage spikes, increase power losses, and cause inrush currents and oscillations. The insulation design of the transformer is also critical in the optimized design of high-frequency transformers.

[0003] Currently, planar transformers are the primary form of high-frequency electronic transformers. Planar transformers offer advantages such as thin profile and large surface area design. Since the winding and core losses of high-frequency transformers are related to different structural and winding designs of planar transformers, both the structural and winding designs must be suitable for high-frequency operating environments. Because winding losses caused by the skin effect and proximity effect reduce system efficiency and power density, to reduce the total power loss of magnetic components in high-frequency transformers, it is necessary to reduce the peak magnetic flux density and the AC resistance value in the windings. To address the aforementioned technical deficiencies, a solution is proposed. Summary of the Invention

[0004] The purpose of this invention is to establish an equivalent loss model and circuit for a high-frequency planar transformer based on the physical structural characteristics of the planar transformer. This model is used to verify the theoretical correctness of the interleaved winding analysis method, which can effectively reduce the peak magnetic flux density, AC resistance value in the winding, and mixed leakage inductance value of the transformer. Furthermore, the interleaved half-turn winding arrangement method helps to simplify the complexity of transformer insulation design and reduce creepage distance and gap distance. At the same time, the interleaved winding arrangement method reduces the number of turns of the planar transformer by creating new windings in space, thereby reducing the leakage inductance value of the planar transformer and increasing the magnetizing inductance, thereby reducing the leakage inductance flux area and increasing the magnetizing inductance flux area.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: an equivalent loss model for a high-frequency planar transformer, including a magnetic core, windings, and a PCB board, wherein the windings include a primary winding and a secondary winding; Six layers of evenly distributed windings are tightly coiled between two adjacent PCB boards. The primary winding serves as the primary winding of the transformer, with a total of 2 layers and located in the center of the PCB board plane. The secondary winding serves as the secondary winding of the transformer, with a total of 4 layers and located on the upper and lower sides of the primary winding. An insulating layer is also connected between two adjacent PCBs. The insulating layer fills the gap between the PCB and the magnetic core. The length of the insulating layer between the primary winding and the PCB is less than the length of the insulating layer between the secondary winding and the PCB, but greater than the length of the insulating layer between the PCB and the magnetic core.

[0006] Furthermore, the insulating layer includes a first insulating layer, a second insulating layer, and a third insulating layer. The magnetic core, the third insulating layer, the secondary winding, the second insulating layer, the primary winding, the first insulating layer, the primary winding, the second insulating layer, the secondary winding, the third insulating layer, the secondary winding, the third insulating layer, and the magnetic core are arranged sequentially from left to right, forming an equivalent loss model circuit. These 15 equivalent loss model circuits together constitute the equivalent loss model of the planar transformer.

[0007] Furthermore, in the equivalent loss model circuit, the magnetic core is located at the leftmost end, representing the leftmost Z. magnetic_loss The third insulating layer between the magnetic core and the secondary winding characterizes Z. Insulation The secondary winding characterizes Z hybrid11 The third insulating layer characterizes X 1;11-12ZInsulation The secondary winding characterizes Z hybrid12 The second insulating layer characterizes Z Insulation The primary winding characterizes Z hybrid21 and Z hybrid24 The first insulating layer characterizes X 2;21-24ZInsulation The primary winding characterizes Z hybrid22 and Z hybrid23 The second insulating layer characterizes Z Insulation The secondary winding characterizes Z hybrid13 The third insulating layer characterizes X 1;13-14ZInsulation The secondary winding characterizes Z hybrid14 The third insulating layer characterizes Z Insulation Magnetic core characterization Z magnetic_loss .

[0008] Furthermore, the connection methods for the 15 structural impedance values ​​include parallel connection and series connection.

[0009] Furthermore, Z magnetic_lossSpecifically, it refers to the impedance associated with core loss, Z. Insulation Specifically, it refers to the impedance associated with the area of ​​the insulating layer; Z hybrid11 Z hybrid12 Z hybrid13 Z hybrid14 Z hybrid21 Z hybrid22 Z hybrid23 Z hybrid24 Specifically, it refers to the impedance associated with the mixed parameters of the primary and secondary sides; X 1;11-12ZInsulation X 1;13-14ZInsulation X 2;21-24ZInsulation Z Insulation Specifically, this refers to the impedance associated with the reduced insulation area due to the staggered winding arrangement between each layer of windings; Z magnetic_loss Specifically, it refers to the impedance associated with the power transmitted by the transformer.

[0010] This invention also provides a method for analyzing interleaved windings in the equivalent loss model of a high-frequency planar transformer, the specific steps of which are as follows: The main structure of a 6-layer planar transformer is constructed using a 6-layer PCB board. The PCB layers consist of two primary winding layers in the center, with two secondary winding layers on each side, totaling four layers. Based on the winding distribution, these layers are divided into half-turn internal current windings and half-turn external current windings. In the three-layer half-turn inner current winding, the winding current at the cross connection point is directed towards the inside of the PCB board, while in the three-layer half-turn outer current winding, the winding current at the cross connection point is directed towards the outside of the PCB board.

[0011] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The equivalent loss model and interleaved winding analysis method of the high-frequency planar transformer: This invention establishes an equivalent loss model and circuit of the high-frequency planar transformer based on the physical structural characteristics of the planar transformer. This is used to verify the theoretical correctness of the interleaved winding analysis method, which can effectively reduce the peak magnetic flux density, AC resistance value in the winding, and mixed leakage inductance value of the transformer. The interleaved half-turn winding arrangement method helps to simplify the complexity of transformer insulation design and reduce creepage distance and gap distance. At the same time, the interleaved winding arrangement method reduces the number of turns of the planar transformer by forming new windings in space, thereby reducing the leakage inductance value of the planar transformer and increasing the magnetizing inductance, thereby reducing the leakage inductance flux area and increasing the magnetizing inductance flux area.

[0012] 2. The equivalent loss model and interleaved winding analysis method of the high-frequency planar transformer are described. Based on the equivalent loss model of the high-frequency planar transformer, the theoretical loss value of the high-frequency transformer optimization design is calculated. This provides important theoretical and practical reference value for the winding distribution, number of coil turns, power loss distribution, voltage ratio and optimal operating frequency of the high-frequency transformer. The winding loss caused by the skin effect and proximity effect reduces the system efficiency and power density. Reducing the peak magnetic flux density and winding AC resistance of the transformer and changing the winding distribution helps to reduce the total power loss of magnetic components in the high-frequency transformer. Attached Figure Description

[0013] Figure 1 This is a front view of the planar transformer structure of the present invention; Figure 2 for Figure 1 The equivalent loss model circuit diagram of the specific architecture of the six-layer planar transformer; Figure 3 for Figure 2 PCB board and interleaved winding arrangement method; In the diagram: 1. Magnetic core; 2. Winding; 3. Primary winding; 4. Secondary winding; 5. PCB board; 6. Insulation layer; 7. Third insulation layer; 8. Second insulation layer; 9. First insulation layer; 10. PCB board layer; 11. Secondary winding; 12. Primary winding; 13. Half-turn internal current winding; 14. Half-turn external current winding. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0015] like Figure 1-3 As shown, the equivalent loss model of the high-frequency planar transformer includes a magnetic core 1, a winding 2, and a PCB board 5. The winding 2 includes a primary winding 3 and a secondary winding 4. Between two adjacent PCB boards 5, six layers of evenly distributed windings 2 are tightly coiled. The primary winding 3 serves as the primary winding of the transformer, with a total of 2 layers and located in the center of the plane of the PCB board 5. The secondary winding 4 serves as the secondary winding of the transformer, with a total of 4 layers and located on the upper and lower sides of the primary winding 3. An insulating layer 6 is also connected between two adjacent PCB boards 5. The insulating layer 6 fills the gap between the PCB board 5 and the magnetic core 1. The length of the insulating layer 6 between the primary winding 3 and the PCB board 5 is less than the length of the insulating layer 6 between the secondary winding 4 and the PCB board 5, but greater than the length of the insulating layer 6 between the PCB board 5 and the magnetic core 1.

[0016] The insulating layers include a first insulating layer 9, a second insulating layer 8, and a third insulating layer 7. The magnetic core 1, the third insulating layer 7, the secondary winding 4, the second insulating layer 8, the primary winding 3, the first insulating layer 9, the primary winding 3, the second insulating layer 8, the secondary winding 4, the third insulating layer 7, the secondary winding 4, the third insulating layer 7, and the magnetic core 1 are arranged sequentially from left to right, forming an equivalent loss model circuit. These 15 equivalent loss model circuits together constitute the equivalent loss model of the planar transformer. In the equivalent loss model circuit, core 1 is located at the leftmost end, representing Z. magnetic_loss The third insulating layer 7 between the magnetic core 1 and the secondary winding 4 characterizes Z. Insulation Secondary winding 4 characterizes Z hybrid11 The third insulating layer 7 characterizes X 1;11-12ZInsulation Secondary winding 4 characterizes Z hybrid12 The second insulating layer 8 characterizes Z. Insulation The primary winding 3 represents Z. hybrid21 and Z hybrid24 The first insulating layer 9 characterizes X 2;21-24ZInsulation The primary winding 3 represents Z. hybrid22 and Z hybrid23 The second insulating layer 8 characterizes Z. Insulation Secondary winding 4 characterizes Z hybrid13 The third insulating layer 7 characterizes X 1;13-14ZInsulation Secondary winding 4 characterizes Z hybrid14 The third insulating layer 7 characterizes Z. Insulation Core 1 characterizes Z magnetic_loss ; The 15 structural impedance values ​​can be connected in parallel or series. Z magnetic_loss Specifically, it refers to the impedance associated with core loss, Z. Insulation Specifically, it refers to the impedance associated with the area of ​​the insulating layer; Z hybrid11 Z hybrid12 Z hybrid13 Z hybrid14 Z hybrid21 Z hybrid22 Z hybrid23 Z hybrid24 Specifically, it refers to the impedance associated with the mixed parameters of the primary and secondary sides; X 1;11-12ZInsulation X1;13-14ZInsulation X 2;21-24ZInsulation Z Insulation Specifically, this refers to the impedance associated with the reduced insulation area due to the staggered winding arrangement between each layer of windings 2; Z magnetic_loss Specifically, it refers to the impedance associated with the power transmitted by the transformer.

[0017] Specifically, the power loss of a high-frequency transformer is related to the core material. Commonly used soft magnetic materials for the core in high-frequency transformers include ferrite, iron-based amorphous materials, and nanocrystalline materials. Ferrites have advantages such as low loss at medium and high frequencies, mature technology, diverse shapes, relatively low design difficulty, and low cost, but they have low saturation flux density, low permeability, low Curie temperature, and poor temperature stability. Iron-based amorphous materials have advantages such as good temperature stability, low annealing temperature, low energy consumption, strong resistance to power waveform distortion, high permeability, low coercivity, and low power loss, but they have a large magnetostriction coefficient, resulting in high noise in power frequency transformers and large transformer size and weight. Nanocrystalline materials have advantages such as no aging stability issues, high temperature stability, high initial permeability, and low coercivity, but they are difficult to develop, relatively difficult to design, and costly.

[0018] Based on the normalized expression for power loss caused by the proximity effect, it can be obtained that the proximity effect loss per unit winding length is directly proportional to the peak value of the external sinusoidal magnetic field caused by the current around the conductor, inversely proportional to the conductor's conductivity, and directly proportional to the effect factor derived from replacing the circular conductor with a square conductor of the same cross-sectional area in the planar transformer structural design. The selected copper wire has a permeability of 4π×10⁻⁷ H / m, a conductivity of 58×10⁶ Ω / m, and a resistivity of 1.68×10⁻⁸ Ω / m. The Steinmetz parameter ranges from 1×10⁻⁶. <a<1.5,1<c<2,1.5<d<2。

[0019] By comparing the transformer loss values ​​of the staggered half-turn winding arrangement and the traditional full winding arrangement in actual parameters, the core loss value Z in the staggered half-turn winding arrangement is shown. magnetic_core Z increases with the increase of insulation-related impedance and horizontal direction variable. Insulation and Z hybrid As the insulation-related impedance and horizontal direction variable increase, the leakage inductance decreases. The interleaved winding arrangement reduces leakage inductance while increasing magnetizing inductance. Due to the increased magnetizing inductance flux area, the transformer's peak flux density will decrease. Insulation and Z hybrid The reduction in [something] causes the AC resistance of the winding to decrease.

[0020] With X 1;11-12ZInsulation X 1;13-14ZInsulation X 2;21-24ZInsulation Z InsulationWith the increase in length, the proximity effect loss per unit winding length (PPE), winding loss (PW), and core loss (PC) of high-frequency transformers will be significantly reduced compared to the traditional full winding arrangement method. Therefore, the staggered half-turn winding arrangement in high-frequency planar transformers can effectively reduce the equivalent total power loss and simultaneously improve the overall operating efficiency and power density of planar transformer systems in high-frequency applications. Example

[0021] The method for analyzing the interleaved windings in constructing an equivalent loss model for a high-frequency planar transformer, with the following specific steps: The main structure of the 6-layer planar transformer is constructed using the 6-layer PCB board 5, namely PCB board layer 10. The center part has 2 layers of primary winding 12, and there are 2 layers of secondary winding 11 on each side, for a total of 4 layers. Based on the distribution position of the winding 2, it is divided into half-turn inner current winding 13 and half-turn outer current winding 14. The winding current of the 3-layer half-turn inner current winding 13 at the cross connection point is directed towards the inside of the PCB board 5, and the winding current of the 3-layer half-turn outer current winding 14 at the cross connection point is directed towards the outside of the PCB board 5. The winding currents at the cross-connection are reversed, so the directions of the magnetic fields generated in space also cancel each other out. That is, all the cross-connection areas are parts of the reduced insulation layer. This not only simplifies the complexity of the insulation design, but also greatly reduces the mixed leakage inductance of the transformer, and improves the transformer's operating efficiency and power density.

[0022] This invention establishes an equivalent loss model and circuit for a high-frequency planar transformer based on the physical structural characteristics of the planar transformer. This model is used to verify the theoretical correctness of the interleaved winding analysis method, which can effectively reduce the peak magnetic flux density, AC resistance value in the winding, and mixed leakage inductance value of the transformer. Furthermore, the interleaved half-turn winding arrangement method helps to simplify the complexity of transformer insulation design and reduce creepage distance and gap distance. At the same time, the interleaved winding arrangement method reduces the number of turns of the planar transformer by creating new windings in space, thereby reducing the leakage inductance value of the planar transformer and increasing the magnetizing inductance, thereby reducing the leakage inductance flux area and increasing the magnetizing inductance flux area.

[0023] In the two embodiments provided in this application, it should be understood that the disclosed apparatus and system can be implemented in other ways; for example, the apparatus embodiments described above are merely illustrative, for example, the division of modules is merely a logical functional division, and there may be other division methods in actual implementation, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed; another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of the apparatus or module can be electrical, mechanical or other forms. The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A model for constructing the equivalent loss of a high-frequency planar transformer, characterized in that, It includes a magnetic core (1), a winding (2) and a PCB board (5), wherein the winding (2) includes a primary winding (3) and a secondary winding (4); Six layers of evenly distributed windings (2) are tightly coiled between two adjacent PCB boards (5). The primary winding (3) serves as the primary winding of the transformer, with a total of 2 layers and located in the center of the plane of the PCB board (5). The secondary winding (4) serves as the secondary winding of the transformer, with a total of 4 layers and located on the upper and lower sides of the primary winding (3). An insulating layer (6) is also connected between two adjacent PCB boards (5). The insulating layer (6) fills the gap between the PCB board (5) and the magnetic core (1). The length of the insulating layer (6) between the primary winding (3) and the PCB board (5) is less than the length of the insulating layer (6) between the secondary winding (4) and the PCB board (5), but greater than the length of the insulating layer (6) between the PCB board (5) and the magnetic core (1).

2. The equivalent loss construction model for a high-frequency planar transformer according to claim 1, characterized in that, The insulating layer includes a first insulating layer (9), a second insulating layer (8), and a third insulating layer (7). The magnetic core (1), the third insulating layer (7), the secondary winding (4), the second insulating layer (8), the primary winding (3), the first insulating layer (9), the primary winding (3), the second insulating layer (8), the secondary winding (4), the third insulating layer (7), the secondary winding (4), the third insulating layer (7), and the magnetic core (1) are arranged sequentially from left to right and combined to form an equivalent loss model circuit. The 15 equivalent loss model circuits together constitute the equivalent loss model of the planar transformer.

3. The equivalent loss construction model for a high-frequency planar transformer according to claim 1, characterized in that, The magnetic core (1) is located at the leftmost end in the equivalent loss model circuit, representing the leftmost end and representing Z. magnetic_loss The third insulating layer (7) between the magnetic core (1) and the secondary winding (4) characterizes Z. Insulation The secondary winding (4) characterizes Z hybrid11 The third insulating layer (7) characterizes X 1;11-12ZInsulation The secondary winding (4) characterizes Z hybrid12 The second insulating layer (8) characterizes Z Insulation The primary winding (3) characterizes Z. hybrid21 and Z hybrid24 The first insulating layer (9) characterizes X 2;21-24ZInsulation The primary winding (3) characterizes Z. hybrid22 and Z hybrid23 The second insulating layer (8) characterizes Z Insulation The secondary winding (4) characterizes Z hybrid13 The third insulating layer (7) characterizes X 1;13-14ZInsulation The secondary winding (4) characterizes Z hybrid14 The third insulating layer (7) characterizes Z Insulation The magnetic core (1) characterizes Z magnetic_loss .

4. The equivalent loss construction model for a high-frequency planar transformer according to claim 3, characterized in that, The connection methods for the 15 structural impedance values ​​include parallel connection and series connection.

5. The equivalent loss construction model for a high-frequency planar transformer according to claim 3, characterized in that, Z magnetic_loss Specifically, it refers to the impedance associated with core loss, Z. Insulation Specifically, it refers to the impedance associated with the area of ​​the insulating layer; Z hybrid11 Z hybrid12 Z hybrid13 Z hybrid14 Z hybrid21 Z hybrid22 Z hybrid23 Z hybrid24 Specifically, it refers to the impedance associated with the mixed parameters of the primary and secondary sides; X 1;11-12ZInsulation X 1;13-14ZInsulation X 2;21-24ZInsulation Z Insulation Specifically, it relates to the impedance associated with the reduced insulation area due to the staggered winding arrangement between each layer of windings (2); Z magnetic_loss Specifically, it refers to the impedance associated with the power transmitted by the transformer.

6. A method for analyzing interleaved windings in constructing an equivalent loss model for a high-frequency planar transformer, characterized in that... The equivalent loss model for the high-frequency planar transformer applied to any one of claims 1-5 is constructed using the following specific steps: The 6-layer PCB board (5) is used to build the main structure of the 6-layer planar transformer, namely the PCB board layer (10). The middle part is the 2-layer primary winding (12), and there are 2-layer secondary windings (11) on each side, for a total of 4 layers. According to the distribution position of the winding (2), it is divided into half-turn inner current winding (13) and half-turn outer current winding (14). The winding current of the 3-layer half-turn inner current winding (13) at the cross connection is directed towards the inside of the PCB board (5), and the winding current of the 3-layer half-turn outer current winding (14) at the cross connection is directed towards the outside of the PCB board (5).

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