Magnetic integrated transformer design method and device for CLLC converter

Abstract

The invention discloses a magnetic integrated transformer design method and device for a CLLC converter, relates to the technical field of high-frequency transformer design, and aims at solving the technical problem that an existing magnetic integrated transformer design method for the CLLC converter is poor in design precision. The method comprises the following steps: based on a preset transformer magnetic circuit model, a preset area product method and preset constraint conditions, determining the total number of turns of primary and secondary winding coils, the number of turns of the primary and secondary winding coils distributed to left and right side columns and the length of left and right side magnetic powder core magnetic columns, further obtaining the magnetic resistance of a magnetic flux branch, and considering the magnetic flux effect of an air gap edge. The accurate air gap length is determined, the magnetic resistance at the corner of the magnetic core and the extra leakage inductance value in air near a winding coil are fully considered, the primary side leakage inductance in a target magnetic core magnetic circuit, the total amount of the target air extra primary side leakage inductance and the magnetic powder core material magnetic conductivity of the target left and right side magnetic powder core magnetic columns are determined, and then a preset coil winding mode is combined. A magnetic integrated transformer for a CLLC converter is designed.

Description

Technical Field

[0001] The present invention relates to the technical field of high-frequency transformer design, and in particular to a magnetic integrated transformer design method and device for a CLLC converter. Background Art

[0002] With the rapid development of the power supply industry, power supplies are continuously optimized towards high frequency, high efficiency, and high power density. The CLLC converter stands out among many topologies with its advantages such as bidirectional flow, high conversion efficiency, and high switching frequency. However, due to the presence of multiple magnetic components, the CLLC converter has the problem of large power supply volume and low power density. If multiple magnetic components can be integrated together through magnetic integration, the volume of the power supply can be greatly reduced and the power density can be increased. Therefore, the magnetic integration technology of the CLLC converter has received extensive attention and research from academia and industry.

[0003] At present, the magnetic integration solutions of CLLC converters are mainly divided into two categories: decoupling integration and leakage inductance integration. The conventional practice of decoupling integration is to wind the resonant inductor and the transformer on different magnetic columns respectively, so that the magnetic flux flow of the two does not interfere with each other, thereby achieving decoupling, and then design the magnetic cores together. However, the volume reduction of magnetic components by decoupling integration is very limited, and only the volume of the two at the connection part of the magnetic core is reduced. Leakage inductance integration is to make the transformer produce a certain value of large leakage inductance, and use a large leakage inductance instead of the resonant inductor. The advantage of this solution is that the volume occupied by the resonant inductor is removed, and a higher power density can be obtained.

[0004] Most of the existing magnetic integrated transformer design methods for CLLC converters can control the leakage inductance by adjusting the air gap size between the middle column and the side column of the magnetic core, as well as the number distribution of the primary and secondary windings on the two side columns of the magnetic core, thereby completing the design of the transformer. However, this method uses a smaller air gap in the side column flux branch to achieve a larger magnetic resistance, resulting in a larger magnetic potential difference at both ends of the air gap, and the leakage flux in the air will also increase, making it impossible to achieve precise control of the leakage inductance of the magnetic integrated transformer, resulting in poor design accuracy of the magnetic integrated transformer used for the CLLC converter. Summary of the invention

[0005] The present invention provides a magnetic integrated transformer design method and device for a CLLC converter, which are used to solve the technical problem that the existing magnetic integrated transformer design method for a CLLC converter cannot achieve accurate control of the leakage inductance of the magnetic integrated transformer, resulting in poor design accuracy of the magnetic integrated transformer for the CLLC converter.

[0006] A first aspect of the present invention provides a magnetic integrated transformer design method for a CLLC converter, comprising:

[0007] Obtaining transformer design parameters, and using a preset area product method to determine the total number of turns of the primary and secondary winding coils, the magnetic core model, and the magnetic core structure geometric parameters corresponding to the magnetic core model according to the transformer design parameters;

[0008] Using preset constraints, according to the transformer design parameters, determine the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the length of the left and right side magnetic powder core magnetic columns, and the electrical isolation distance between the left and right side inner and outer coils;

[0009] Using a preset transformer magnetic circuit model, according to the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the total number of turns of the primary and secondary winding coils and the transformer design parameters, the magnetic flux of the magnetic flux branch, the total magnetic resistance of the side column magnetic flux branch and the total magnetic resistance of the middle column magnetic flux branch are calculated;

[0010] Determining the precise middle column air gap length according to the total magnetic resistance of the middle column magnetic flux branch and the geometric parameters of the magnetic core structure;

[0011] The magnetic core corners of the left and right side columns are calculated by using a preset magnetic core corner model according to the magnetic core structure geometric parameters and the magnetic flux branch magnetic flux;

[0012] Determine the magnetic resistance of the left and right magnetic powder core columns and the magnetic permeability of the magnetic powder core materials of the left and right magnetic powder core columns based on the magnetic core structure geometric parameters, the lengths of the left and right magnetic powder core columns, the magnetic flux of the magnetic flux branch, and the total magnetic resistance of the side column magnetic flux branch;

[0013] Determine the primary leakage inductance in the target magnetic core magnetic circuit, the additional leakage inductance in the air near the target winding coil, and the magnetic permeability of the magnetic powder core material of the target left and right magnetic powder core columns according to the total magnetic resistance of the side column magnetic flux branch, the geometric parameters of the magnetic core structure, the total magnetic resistance of the middle column magnetic flux branch, the magnetic flux of the magnetic flux branch, the magnetic resistance of the left and right magnetic powder core columns, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the transformer design parameters, the length of the left and right magnetic powder core columns, the electrical isolation distance between the left and right inner and outer coils, the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns, and the preset design leakage inductance;

[0014] Based on the preset coil winding method, a magnetic integrated transformer for CLLC converter is designed through the sum of the primary leakage inductance in the target magnetic core magnetic circuit and the additional leakage inductance in the air near the target winding coil, the length of the left and right magnetic powder core magnetic columns, the precise middle column air gap length, and the magnetic permeability of the magnetic powder core material of the target left and right magnetic powder core magnetic columns.

[0015] Optionally, the preset constraint condition is specifically:

[0016] The product of the number of turns of the primary winding coil allocated to the left side column and the number of turns of the secondary winding coil is equal to the product of the number of turns of the primary winding coil allocated to the right side column and the number of turns of the secondary winding coil.

[0017] Optionally, the number of turns of the primary and secondary winding coils allocated to the left and right side columns include the number of turns of the primary winding coils of the left side column, the number of turns of the secondary winding coils of the left side column, the number of turns of the primary winding coils of the right side column, and the number of turns of the secondary winding coils of the right side column; the lengths of the left and right magnetic powder core magnetic columns include the length of the left magnetic powder core magnetic column and the length of the right magnetic powder core magnetic column; the use of preset constraints to determine the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the lengths of the left and right magnetic powder core magnetic columns, and the electrical isolation distance between the left and right inner and outer coils according to the transformer design parameters includes:

[0018] Calculate the number of turns of the primary winding coil of the left side column, the number of turns of the secondary winding coil of the left side column, the number of turns of the primary winding coil of the right side column, and the number of turns of the secondary winding coil of the right side column according to the primary resonant inductance value and the secondary resonant inductance value in the transformer design parameters by using preset constraints;

[0019] Based on the number of turns of the primary winding coil of the left side column and the number of turns of the secondary winding coil of the left side column, determine the width of the primary winding coil of the left side column and the width of the secondary winding coil of the left side column in the case of tight winding;

[0020] Comparing the left side column primary winding coil width and the left side column secondary winding coil width in a tightly wound state;

[0021] The largest left-side column primary winding coil width or the left-side column secondary winding coil width is used as the target left-side column winding coil width, and based on the target left-side column winding coil width, the left-side magnetic powder core magnetic column length is determined;

[0022] Based on the number of turns of the primary winding coil of the right side column and the number of turns of the secondary winding coil of the right side column, determine the width of the primary winding coil of the right side column and the width of the secondary winding coil of the right side column in the case of tight winding;

[0023] Comparing the primary winding coil width of the right side column and the secondary winding coil width of the right side column in a tightly wound state;

[0024] The largest right-side column primary winding coil width or the right-side column secondary winding coil width is used as the target right-side column winding coil width, and based on the target right-side column winding coil width, the right-side magnetic powder core magnetic column length is determined;

[0025] The electrical isolation distance between the inner and outer coils on the left and right sides is calculated according to the transformer input voltage and the transformer output voltage in the transformer design parameters.

[0026] Optionally, the use of a preset transformer magnetic circuit model to calculate the magnetic flux of the magnetic flux branch, the total magnetic resistance of the side column magnetic flux branch, and the total magnetic resistance of the middle column magnetic flux branch according to the turns of the primary and secondary winding coils allocated to the left and right side columns, the total turns of the primary and secondary winding coils, and the transformer design parameters includes:

[0027] According to the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the primary resonant inductance value, the secondary resonant inductance value, the primary excitation inductance value of the transformer, and the total number of turns of the primary and secondary winding coils, the total magnetic resistance of the side column magnetic flux branch and the total magnetic resistance of the middle column magnetic flux branch are calculated;

[0028] The preset transformer magnetic circuit model is divided to generate a left side column magnetic flux branch, a right side column magnetic flux branch and a middle column magnetic flux branch;

[0029] The magnetic flux branch method is used to model the magnetic flux branch of the left side column, the magnetic flux branch of the right side column and the magnetic flux branch of the middle column, and a relationship equation group between the magnetic flux branch of the left side column, the magnetic flux branch of the right side column and the magnetic flux branch of the middle column is generated;

[0030] The magnetic flux of the magnetic flux branch is calculated by using the relationship equation group between the left side column magnetic flux branch, the right side column magnetic flux branch and the middle column magnetic flux branch according to the total magnetic resistance of the side column magnetic flux branch, the total magnetic resistance of the middle column magnetic flux branch, the total number of turns of the primary and secondary winding coils, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, and the primary winding coil current and the secondary winding coil current in the transformer design parameters;

[0031] ;

[0032] Among them, A is the total magnetic resistance parameter of the first side column; B is the total magnetic resistance parameter of the second side column; C is the total magnetic resistance parameter of the third side column; D is the total magnetic resistance parameter of the first middle column; E is the total magnetic resistance parameter of the second middle column; F is the total magnetic resistance parameter of the third middle column; G is the total magnetic resistance parameter of the fourth middle column; H is the total magnetic resistance parameter of the fifth middle column; is the total magnetic resistance of the side column flux branch; is the total magnetic resistance of the center column flux branch; is the primary resonant inductance value; is the secondary side resonant inductance value; The number of turns of the primary winding coil assigned to the left side column; The number of turns of the secondary winding coil allocated to the left column; is the total number of turns of the secondary winding coil; is the total number of turns of the primary winding coil; The number of turns of the primary winding coil allocated to the right column; The number of turns of the secondary winding coil allocated to the right column; is the primary magnetizing inductance of the transformer.

[0033] Optionally, the magnetic flux of the magnetic flux branch includes the magnetic flux of the left side column magnetic flux branch and the magnetic flux of the right side column magnetic flux branch; the preset magnetic core corner model includes the left side column magnetic core corner model and the right side column magnetic core corner model; the magnetic resistance at the left and right side column magnetic core corners includes the magnetic resistance at the left side column magnetic core corner and the magnetic resistance at the right side column magnetic core corner; the use of the preset magnetic core corner model to calculate the magnetic resistance at the left and right side column magnetic core corners according to the magnetic core structure geometric parameters and the magnetic flux branch magnetic flux includes:

[0034] The left-side column magnetic core corner model and the right-side column magnetic core corner model are divided respectively by using the width of the magnetic core side column in the magnetic core structure geometric parameters, and the first magnetic core corner area, the second magnetic core corner area, the third magnetic core corner area and the corner area inside the magnetic core window corresponding to the left-side column magnetic core corner model and the right-side column magnetic core corner model are determined;

[0035] Using the magnetic flux of the left-side column magnetic flux branch, the width of the core side column in the core structure geometric parameters and the thickness of the core, magnetic resistance calculation is performed on the first core corner area, the second core corner area, the third core corner area and the corner area inside the core window corresponding to the left-side column core corner model to determine the magnetic resistance of the first core corner area, the second core corner area, the third core corner area and the corner area inside the core window corresponding to the left-side column core corner model;

[0036] The magnetic resistance of the first magnetic core corner area, the magnetic resistance of the second magnetic core corner area, the magnetic resistance of the third magnetic core corner area and the magnetic resistance of the corner area in the core window corresponding to the left side column magnetic core corner model are connected in parallel to determine the magnetic resistance at the left side column magnetic core corner;

[0037] Using the magnetic flux of the right-side column magnetic flux branch, the width of the core side column in the core structure geometric parameters and the thickness of the core, magnetic resistance calculation is performed on the first core corner area, the second core corner area, the third core corner area and the corner area inside the core window corresponding to the right-side column core corner model to determine the magnetic resistance of the first core corner area, the second core corner area, the third core corner area and the corner area inside the core window corresponding to the right-side column core corner model;

[0038] The magnetic resistance of the first core corner area, the magnetic resistance of the second core corner area, the magnetic resistance of the third core corner area and the magnetic resistance of the corner area in the core window corresponding to the right side column core corner model are connected in parallel to determine the magnetic resistance at the right side column core corner.

[0039] Optionally, the magnetic resistance of the left and right magnetic powder core columns includes the magnetic resistance of the left magnetic powder core column and the magnetic resistance of the right magnetic powder core column; the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns includes the magnetic permeability of the magnetic powder core material of the left magnetic powder core column and the magnetic permeability of the magnetic powder core material of the right magnetic powder core column; the magnetic resistance of the left and right magnetic powder core columns and the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns based on the magnetic core structure geometric parameters, the lengths of the left and right magnetic powder core columns, the magnetic flux of the magnetic flux branch, and the total magnetic resistance of the side column magnetic flux branch, includes:

[0040] The magnetic resistance of the left residual magnetic core magnetic circuit and the magnetic resistance of the right residual magnetic core magnetic circuit are calculated by using the magnetic column length of the left magnetic powder core, the magnetic column length of the right magnetic powder core, the magnetic flux of the magnetic flux branch, the width of the magnetic core window in the magnetic core structure geometric parameters, the height of the magnetic core window, the width of the magnetic core side column, and the thickness of the magnetic core;

[0041] Calculate the magnetic resistance of the left magnetic powder core magnetic column according to the magnetic resistance of the left residual magnetic core magnetic circuit and the total magnetic resistance of the side column magnetic flux branch;

[0042] Calculate the magnetic resistance of the right magnetic powder core magnetic column according to the magnetic resistance of the right residual magnetic core magnetic circuit and the total magnetic resistance of the side column magnetic flux branch;

[0043] Calculate the magnetic permeability of the magnetic powder core material of the left magnetic powder core column based on the magnetic resistance of the left magnetic powder core column, the length of the left magnetic powder core column, the width of the magnetic core side column in the magnetic core structure geometric parameters, and the thickness of the magnetic core;

[0044] The magnetic permeability of the magnetic powder core material of the right magnetic powder core column is calculated based on the magnetic resistance of the right magnetic powder core column, the length of the right magnetic powder core column, the width of the core side column in the magnetic core structure geometric parameters, and the thickness of the magnetic core.

[0045] Optionally, the method of determining the primary leakage inductance in the target magnetic core magnetic circuit, the additional leakage inductance in the air near the target winding coil, and the magnetic permeability of the magnetic powder core material of the target left and right magnetic powder core columns according to the total magnetic resistance of the side column magnetic flux branch, the geometric parameters of the magnetic core structure, the total magnetic resistance of the middle column magnetic flux branch, the magnetic flux of the magnetic flux branch, the magnetic resistance of the left and right magnetic powder core columns, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the transformer design parameters, the length of the left and right magnetic powder core columns, the electrical isolation distance between the left and right inner and outer coils, the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns, and the preset design leakage inductance includes:

[0046] The additional leakage inductance in the air near the initial winding coil is calculated by using the magnetic resistance of the left and right magnetic powder core columns, the magnetic flux of the magnetic flux branch, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the length of the left and right magnetic powder core columns, the electrical isolation distance between the left and right inner and outer coils, the geometric parameters of the magnetic core structure and the transformer design parameters;

[0047] Based on the preset designed leakage inductance, determining the primary leakage inductance in the initial magnetic core magnetic circuit;

[0048] Fine-tune the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns to determine the magnetic permeability of the magnetic powder core material of the middle left and right magnetic powder core columns;

[0049] The magnetic resistance of the left and right magnetic powder core columns is updated by using the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns, the length of the left and right magnetic powder core columns, the width of the magnetic core side columns in the transformer design parameters, and the thickness of the magnetic core to determine the magnetic resistance of the left and right magnetic powder core columns in the middle;

[0050] The primary leakage inductance in the initial magnetic core magnetic circuit is updated by using the total magnetic resistance of the side column magnetic flux branch, the magnetic resistance of the left and right magnetic powder core magnetic columns in the middle, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, and the total magnetic resistance of the middle column magnetic flux branch to determine the primary leakage inductance in the middle magnetic core magnetic circuit;

[0051] The additional leakage inductance in the air near the initial winding coil is updated based on the magnetic resistance of the magnetic powder core columns on the left and right sides of the middle, and the additional leakage inductance in the air near the middle winding coil is determined;

[0052] Determine whether the sum of the additional leakage inductance in the air near the intermediate winding coil and the primary leakage inductance in the intermediate magnetic core magnetic circuit is equal to the preset design leakage inductance;

[0053] If so, the additional leakage inductance in the air near the middle winding coil is used as the additional leakage inductance in the air near the target winding coil, the primary leakage inductance in the middle magnetic core magnetic circuit is used as the primary leakage inductance in the target magnetic core magnetic circuit, and the magnetic permeability of the magnetic powder core material of the middle left and right magnetic powder core columns is used as the magnetic permeability of the magnetic powder core material of the target left and right magnetic powder core columns.

[0054] Optionally, the additional leakage inductance in the air near the initial winding coil is calculated by using the magnetic resistance of the left and right magnetic powder core columns, the magnetic flux of the magnetic flux branch, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the length of the left and right magnetic powder core columns, the electrical isolation distance between the left and right inner and outer coils, the magnetic core structure geometric parameters and the transformer design parameters, including:

[0055] Calculate the magnetic voltage drop at both ends of the left and right magnetic powder core columns by using the magnetic resistance of the left and right magnetic powder core columns and the magnetic flux of the magnetic flux branch;

[0056] According to the magnetic voltage drop at both ends of the left and right magnetic powder core magnetic columns, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the length of the left and right magnetic powder core magnetic columns, the electrical isolation distance between the left and right inner and outer coils, and the transformer design parameters, calculate the magnetic field strength in the primary winding coils of the left and right side columns, the magnetic field strength in the electrical isolation layer of the left and right side columns, and the magnetic field strength in the secondary winding coils of the left and right side columns;

[0057] The total air leakage inductance energy of the left and right side column winding coils is calculated by using the magnetic field strength in the primary winding coils of the left and right side columns, the magnetic field strength in the electrical isolation layer of the left and right side columns, the magnetic field strength in the secondary winding coils of the left and right side columns, and the geometric parameters of the magnetic core structure;

[0058] Based on the total air leakage inductance energy of the left and right side column winding coils and the transformer design parameters, determine the primary leakage inductance on the left side column and the primary leakage inductance on the right side column;

[0059] The primary leakage inductance on the left side column and the primary leakage inductance on the right side column are added to determine the additional leakage inductance in the air near the initial winding coil.

[0060] Optionally, the precise middle column air gap length is specifically:

[0061] ;

[0062] in, is the precise center column air gap length; is the total magnetic resistance of the middle column magnetic flux branch; a is the first accurate middle column air gap length parameter; b is the second accurate middle column air gap length parameter; c is the third accurate middle column air gap length parameter; d is the fourth accurate middle column air gap length parameter; is the height of the core window; is the width of the core column; is the thickness of the magnetic core; is the magnetic permeability of the core material of the EE type core used; is the magnetic permeability of air.

[0063] A second aspect of the present invention provides a magnetic integrated transformer design device for a CLLC converter, comprising:

[0064] An acquisition module is used to acquire transformer design parameters, and determine the total number of turns of the primary and secondary winding coils, the core model, and the core structure geometric parameters corresponding to the core model according to the transformer design parameters by using a preset area product method;

[0065] The first calculation module is used to determine the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the length of the left and right side magnetic powder core magnetic columns, and the electrical isolation distance between the left and right side inner and outer layer coils according to the transformer design parameters by using preset constraints;

[0066] The second calculation module is used to calculate the magnetic flux of the magnetic flux branch, the total magnetic resistance of the side column magnetic flux branch and the total magnetic resistance of the middle column magnetic flux branch according to the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the total number of turns of the primary and secondary winding coils and the transformer design parameters by using a preset transformer magnetic circuit model;

[0067] A third calculation module is used to determine the precise middle column air gap length according to the total magnetic resistance of the middle column magnetic flux branch and the geometric parameters of the magnetic core structure;

[0068] A fourth calculation module is used to calculate the magnetic resistance at the corners of the left and right side column magnetic cores according to the geometric parameters of the magnetic core structure and the magnetic flux of the magnetic flux branch by using a preset magnetic core corner model;

[0069] A fifth calculation module is used to determine the magnetic resistance of the left and right magnetic powder core columns and the magnetic permeability of the magnetic powder core materials of the left and right magnetic powder core columns based on the magnetic core structure geometric parameters, the lengths of the left and right magnetic powder core columns, the magnetic flux of the magnetic flux branch, and the total magnetic resistance of the side column magnetic flux branch;

[0070] The target parameter output module is used to determine the primary leakage inductance in the target magnetic core magnetic circuit, the additional leakage inductance in the air near the target winding coil, and the magnetic permeability of the magnetic powder core material of the target left and right magnetic powder core columns according to the total magnetic resistance of the side column magnetic flux branch, the geometric parameters of the magnetic core structure, the total magnetic resistance of the middle column magnetic flux branch, the magnetic flux of the magnetic flux branch, the magnetic resistance of the left and right magnetic powder core columns, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the transformer design parameters, the length of the left and right magnetic powder core columns, the electrical isolation distance between the left and right inner and outer coils, the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns, and the preset design leakage inductance;

[0071] The design module is used to design a magnetic integrated transformer for a CLLC converter based on a preset coil winding method, through the sum of the primary leakage inductance in the target core magnetic circuit and the additional leakage inductance in the air near the target winding coil, the length of the left and right magnetic powder core magnetic columns, the precise middle column air gap length, and the magnetic permeability of the magnetic powder core material of the target left and right magnetic powder core magnetic columns.

[0072] It can be seen from the above technical solutions that the present invention has the following advantages:

[0073] The above technical solution of the present invention provides a magnetic integrated transformer design method for a CLLC converter. First, the transformer design parameters are obtained, and the preset area product method is used to determine the total number of turns of the primary and secondary winding coils, the magnetic core model, and the magnetic core structure geometric parameters corresponding to the magnetic core model according to the transformer design parameters; then, the preset constraints are used to determine the number of turns of the primary and secondary winding coils assigned to the left and right side columns, the length of the left and right side magnetic powder core magnetic columns, and the electrical isolation distance between the left and right inner and outer coils according to the transformer design parameters; the preset transformer magnetic circuit model is used to determine the number of turns of the primary and secondary winding coils assigned to the left and right side columns, the original The total number of turns of the secondary winding coil and the design parameters of the transformer are used to calculate the magnetic flux of the flux branch, the total magnetic resistance of the side column magnetic flux branch and the total magnetic resistance of the middle column magnetic flux branch; the precise middle column air gap length is determined based on the total magnetic resistance of the middle column magnetic flux branch and the geometric parameters of the core structure; the magnetic resistance at the corners of the left and right side column magnetic cores is calculated using the preset core corner model based on the core structure geometric parameters and the magnetic flux of the flux branch; the magnetic resistance of the left and right side powder core magnetic columns and the magnetic permeability of the powder core material of the left and right side powder core magnetic columns are determined based on the core structure geometric parameters, the length of the left and right side powder core magnetic columns, the magnetic flux of the flux branch and the total magnetic resistance of the side column magnetic flux branch; the magnetic resistance of the left and right side powder core magnetic columns and the magnetic permeability of the powder core material of the left and right side powder core magnetic columns are determined based on the total magnetic resistance of the side column magnetic flux branch The magnetic resistance, core structure geometric parameters, total magnetic resistance of the middle column magnetic flux branch, magnetic flux of the magnetic flux branch, magnetic resistance of the left and right magnetic powder core columns, the number of turns of the primary and secondary winding coils assigned to the left and right side columns, transformer design parameters, lengths of the left and right magnetic powder core columns, electrical isolation distance between the left and right inner and outer coils, magnetic permeability of the magnetic powder core materials of the left and right magnetic powder core columns and preset design leakage inductance are used to determine the primary leakage inductance in the target magnetic core magnetic circuit, the additional leakage inductance in the air near the target winding coil and the magnetic permeability of the magnetic powder core materials of the target left and right magnetic powder core columns; finally, based on the preset coil winding method, the primary leakage inductance in the target magnetic core magnetic circuit and the target winding are used to determine the primary leakage inductance in the target magnetic core magnetic circuit and the target winding The sum of the extra leakage inductance in the air near the winding coil, the length of the left and right magnetic powder core columns, the precise middle column air gap length, and the magnetic permeability of the magnetic powder core materials of the target left and right magnetic powder core columns are used to design a magnetic integrated transformer for the CLLC converter; based on the above scheme, the present invention combines the preset coil winding method and the equal length of the left and right magnetic powder core columns to make the leakage flux distribution in the air near the winding coil more regular. At the same time, the core corner, the precise middle column air gap length, and the extra leakage inductance of the air are taken into consideration, thereby achieving precise control of the transformer leakage inductance, thereby improving the design accuracy of the magnetic integrated transformer for the CLLC converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0075] Figure 1 A flowchart of a method for designing a magnetic integrated transformer for a CLLC converter provided in Embodiment 1 of the present invention;

[0076] Figure 2 A schematic diagram of the structure of a magnetic integrated transformer for a CLLC converter provided in Embodiment 1 of the present invention;

[0077] Figure 3 A geometric structure diagram of an EE-type magnetic core provided in Embodiment 1 of the present invention;

[0078] Figure 4 A schematic diagram of the structure of a simplified magnetic circuit model of a transformer provided in Embodiment 1 of the present invention;

[0079] Figure 5 A schematic diagram of the structure of a transformer circuit model provided in Embodiment 1 of the present invention;

[0080] Figure 6 A schematic structural diagram of a center column model with an air gap provided in Embodiment 1 of the present invention;

[0081] Figure 7 A schematic structural diagram of a magnetic core corner model provided in Embodiment 1 of the present invention;

[0082] Figure 8 A simplified structural diagram of the left side column and winding coil provided in the first embodiment of the present invention;

[0083] Fig. 9 A schematic flow chart of a magnetic integrated transformer design method for a CLLC converter provided in Embodiment 2 of the present invention;

[0084] Fig.10 A structural block diagram of a magnetic integrated transformer design device for a CLLC converter provided in Embodiment 3 of the present invention;

[0085] The meanings of the symbols in the accompanying drawings are as follows:

[0086] 1. EE type magnetic core; 2. Middle column air gap; 3. Left side magnetic powder core column; 4. Right side magnetic powder core column; 5. Left side column secondary winding coil; 6. Right side column secondary winding coil; 7. Left side column primary winding coil; 8. Right side column primary winding coil; 9. Side column magnetic core; 10. Magnetic powder core column; 11. Primary winding; 12. Secondary winding. DETAILED DESCRIPTION

[0087] An embodiment of the present invention provides a magnetic integrated transformer design method and device for a CLLC converter, which is used to solve the technical problem that the existing magnetic integrated transformer design method for a CLLC converter cannot achieve accurate control of the leakage inductance of the magnetic integrated transformer, resulting in poor design accuracy of the magnetic integrated transformer for the CLLC converter.

[0088] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0089] Terminology explanation: CLLC converter (Capacitor-Inductor-Inductor-Capacitor Converter) is a power conversion device that can convert direct current (DC) into direct current (DC).

[0090] See also Figure 1 , Figure 1 A flowchart of the steps of a magnetic integrated transformer design method for a CLLC converter provided in Embodiment 1 of the present invention.

[0091] The present invention provides a magnetic integrated transformer design method for a CLLC converter, comprising:

[0092] Step 101: Obtain transformer design parameters, and use a preset area product method to determine the total number of turns of the primary and secondary winding coils, the core model, and the core structure geometric parameters corresponding to the core model according to the transformer design parameters.

[0093] The preset area product method is the traditional AP method (Area Product Method).

[0094] The core model is the specific model of the selected EE type core.

[0095] Please note that Figure 2 The structure of the magnetic integrated transformer proposed by the present invention is as follows: Figure 2 As shown, the transformer core adopts an EE type core structure, the primary winding coil and the secondary winding coil are wound on the left side column and the right side column of the core, and magnetic powder core columns with the same length as the winding coil are placed on the left side column and the right side column respectively, and an air gap is opened in the middle column of the core.

[0096] Furthermore, the obtained transformer design parameters are used as the initial input of the present invention, and the transformer design parameters include the turns ratio of the primary and secondary winding coils. , primary winding coil current , secondary winding coil current , primary resonant inductance , secondary side resonant inductance value , transformer primary magnetizing inductance , Transformer input voltage , Transformer output voltage , switching frequency .

[0097] For further information, see Figure 3 After obtaining the relevant design parameters, the specific model of the EE-type magnetic core is calculated and selected according to the traditional AP method, and the relevant structural geometric parameters of the EE-type magnetic core are obtained as follows: Figure 3 As shown, the core structure geometric parameters include: the width of the core side column , Width of the core window , the width of the core column , the height of the upper and lower yokes of the core , the height of the core window and the thickness of the core . Side column width and upper and lower yoke height equal.

[0098] Set the maximum working flux density of the core to , the total number of turns of the primary and secondary winding coils can be calculated. The total number of turns of the primary and secondary winding coils includes the total number of turns of the primary winding coils. and the total number of turns of the secondary winding coil ; The process can be expressed as:

[0099] ;

[0100] ;

[0101] It is worth mentioning that according to the set current density of the coil winding, the wire diameter of the primary winding coil can be obtained and the wire diameter of the secondary winding coil .

[0102] Step 102, using preset constraints and according to transformer design parameters, determine the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the length of the left and right side magnetic powder core magnetic columns, and the electrical isolation distance between the left and right side inner and outer coils.

[0103] The primary and secondary winding coil turns allocated to the left and right side columns include the primary winding coil turns of the left side column, the secondary winding coil turns of the left side column, the primary winding coil turns of the right side column, and the secondary winding coil turns of the right side column.

[0104] The lengths of the left and right magnetic powder core columns include the length of the left magnetic powder core column and the length of the right magnetic powder core column.

[0105] The electrical isolation distance between the inner and outer coils on the left and right sides includes the electrical isolation distance between the inner coil and the outer coil on the left side column and the electrical isolation distance between the inner coil and the outer coil on the right side column.

[0106] The preset constraint condition is that the product of the number of turns of the primary winding coil assigned to the left side column and the number of turns of the secondary winding coil is equal to the product of the number of turns of the primary winding coil assigned to the right side column and the number of turns of the secondary winding coil.

[0107] Specifically, step 102 may include the following sub-steps S21-S28:

[0108] Step S21, using preset constraints and according to the primary resonant inductance and the secondary resonant inductance in the transformer design parameters, calculate the number of turns of the primary winding coil of the left side column, the number of turns of the secondary winding coil of the left side column, the number of turns of the primary winding coil of the right side column, and the number of turns of the secondary winding coil of the right side column;

[0109] It should be noted that for a symmetrical CLLC converter, the primary resonant inductance is Resonant inductance value with secondary side The ratio is equal to the square of the ratio of the number of turns of the primary side to the number of turns of the secondary side. According to this relationship, the preset constraint condition can be deduced that the product of the number of turns of the primary winding coil assigned to the left side column and the number of turns of the secondary winding coil is equal to the product of the number of turns of the primary winding coil assigned to the right side column and the number of turns of the secondary winding coil, thereby calculating the number of turns of the primary winding assigned to the left side column. , Secondary winding turns , the number of primary winding turns allocated to the right side column , Secondary winding turns , , , , are integers and satisfy and The difference is the smallest, and this turns allocation method is the optimal turns allocation method.

[0110] Step S22, based on the number of turns of the primary winding coil of the left side column and the number of turns of the secondary winding coil of the left side column, determine the width of the primary winding coil of the left side column and the width of the secondary winding coil of the left side column in the case of tight winding;

[0111] Step S23, comparing the width of the primary winding coil of the left side column and the width of the secondary winding coil of the left side column in the case of tight winding;

[0112] Step S24, taking the largest left side column primary winding coil width or the left side column secondary winding coil width as the target left side column winding coil width, and determining the left magnetic powder core magnetic column length based on the target left side column winding coil width;

[0113] It should be noted that the coil width of the primary winding on the left side column is calculated under the condition of tight winding. , calculate the coil width of the secondary winding on the left side column when it is tightly wound , take the maximum value of the two as the design coil width of the left side column (that is, the target left side column winding coil width ),Right now Comparing the primary winding coil and the secondary winding coil on the left side column, the coil with a larger coil width is wound in the inner layer under tight winding. The winding method is tight winding, and the winding coil width is The coil with smaller coil width is wound on the outer layer, and the winding method is uniform winding. The coil width is also equal to , so that the primary winding coil and the secondary winding coil on the left column are equal in length. Let the length of the left magnetic powder core column be equal to the design coil width of the left column .

[0114] Step S25, based on the number of turns of the primary winding coil of the right side column and the number of turns of the secondary winding coil of the right side column, determine the width of the primary winding coil of the right side column and the width of the secondary winding coil of the right side column in the case of tight winding;

[0115] Step S26, comparing the width of the primary winding coil of the right side column and the width of the secondary winding coil of the right side column in the case of tight winding;

[0116] Step S27, taking the largest right side column primary winding coil width or the right side column secondary winding coil width as the target right side column winding coil width, and determining the right side magnetic powder core magnetic column length based on the target right side column winding coil width;

[0117] It should be noted that based on the above-mentioned steps and principles for calculating the coil width of the primary winding on the left side column under the condition of tight winding, the coil width of the primary winding on the right side column under the condition of tight winding is calculated. , calculate the coil width of the secondary winding on the right side column when it is tightly wound , take the maximum value of the two as the design coil width of the right side column (i.e. the target right side column winding coil width) ,Right now Comparing the primary winding coil and the secondary winding coil on the right side column, the coil with a larger coil width is wound in the inner layer under tight winding. The winding method is tight winding, and the winding coil width is The coil with smaller coil width is wound on the outer layer, and the winding method is uniform winding. The coil width is also equal to , so that the length of the primary winding coil and the secondary winding coil on the right side column are equal. Let the length of the magnetic powder core column on the right side be equal to the design coil width of the right side column .

[0118] Step S28: Calculate the electrical isolation distance between the inner and outer coils on the left and right sides according to the transformer input voltage and the transformer output voltage in the transformer design parameters.

[0119] It should be noted that the electrical isolation distance between the inner coil and the outer coil on the left side column is determined based on the input voltage and output voltage of the transformer. The electrical isolation distance between the inner coil and the outer coil on the right side column .

[0120] Step 103, using a preset transformer magnetic circuit model, according to the primary and secondary winding coil turns allocated to the left and right side columns, the total number of primary and secondary winding coil turns and the transformer design parameters, calculate the magnetic flux of the magnetic flux branch, the total magnetic resistance of the side column magnetic flux branch and the total magnetic resistance of the middle column magnetic flux branch.

[0121] Specifically, step 103 may include the following sub-steps S31-S34:

[0122] Step S31, calculating the total magnetic resistance of the side column magnetic flux branch and the total magnetic resistance of the middle column magnetic flux branch according to the primary and secondary winding coil turns allocated to the left and right side columns, the primary resonant inductance value, the secondary resonant inductance value in the transformer design parameters, the primary excitation inductance value of the transformer, and the total number of primary and secondary winding coil turns;

[0123] Step S32, dividing the preset transformer magnetic circuit model to generate a left side column magnetic flux branch, a right side column magnetic flux branch and a middle column magnetic flux branch;

[0124] Step S33, using the magnetic flux branch method to model the magnetic flux branch of the left side column, the magnetic flux branch of the right side column and the magnetic flux branch of the middle column, and generating a relationship equation group between the magnetic flux branch of the left side column, the magnetic flux branch of the right side column and the magnetic flux branch of the middle column;

[0125] Step S34, using the relationship equation group between the left side column magnetic flux branch, the right side column magnetic flux branch and the middle column magnetic flux branch, according to the total magnetic resistance of the side column magnetic flux branch, the total magnetic resistance of the middle column magnetic flux branch, the total number of turns of the primary and secondary winding coils, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the primary winding coil current and the secondary winding coil current in the transformer design parameters, calculate the magnetic flux branch magnetic flux.

[0126] Please note that Figure 4 The simplified magnetic circuit model of the transformer established by the present invention is as follows: Figure 4 As shown in the figure, the magnetic circuit is divided into three branches, including the left side column magnetic flux branch, the right side column magnetic flux branch and the middle column magnetic flux branch. The exciting magnetic potential on the left side column is , the demagnetizing potential is , the exciting magnetic potential on the right side column is , the demagnetizing potential is The total magnetic resistance of the magnetic flux branches on both sides is , the total magnetic resistance of the middle column magnetic flux branch is , is the magnetic flux of the left side column flux branch, is the magnetic flux of the middle column flux branch, is the magnetic flux of the right side column flux branch.

[0127] According to the flux branch method, the relationship between the magnetic potential, magnetic resistance and flux of the three flux branches can be listed, that is, the relationship between the left side column flux branch, the right side column flux branch and the middle column flux branch (4-1):

[0128] (4-1)

[0129] Solving equation (4-1) yields the flux expressions (4-2) for the three flux branches:

[0130] (4-2)

[0131] Among them, after obtaining the total magnetic resistance of the side column flux branch and the total magnetic resistance of the middle column flux branch, the total number of turns of the primary and secondary winding coils, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, and the primary winding coil current and secondary winding coil current in the transformer design parameters are substituted into formula (4-2) to obtain the magnetic flux branch magnetic flux. The magnetic flux branch magnetic flux includes the magnetic flux of the left side column magnetic flux branch. , magnetic flux of the right side column magnetic flux branch and the center column flux branch magnetic flux .

[0132] For further information, see Figure 5 The circuit model of the magnetic integrated transformer of the CLLC converter is as follows: Figure 5 As shown, is the input voltage of the transformer, is the output voltage of the transformer. According to Faraday's law of electromagnetic induction, the expression of input and output voltage with respect to the number of turns of the winding coil and the magnetic flux can be obtained (4-3):

[0133] (4-3)

[0134] In formula (4-2), and Substitute the expression into formula (4-3) and simplify it to get formula (4-4):

[0135] (4-4)

[0136] Based on the above foundation, the self-inductance of the primary winding coil can be obtained , Self-inductance of the secondary winding coil Mutual inductance with the primary and secondary coils The expression (4-5):

[0137] (4-5)

[0138] The excitation inductance of the primary side of the transformer can be further derived , primary resonant inductor and secondary resonant inductor The expression (4-6):

[0139] (4-6)

[0140] Finally, the total magnetic resistance of the side column flux branch is obtained and the total magnetic resistance of the center column flux branch The expression (4-7):

[0141] (4-7)

[0142] Among them, the number of turns of the primary and secondary winding coils assigned to the left and right side columns, the primary resonant inductance value, the secondary resonant inductance value, the primary excitation inductance value of the transformer in the design parameters, and the total number of turns of the primary and secondary winding coils are substituted into formula (4-7) to calculate the total magnetic resistance of the side column magnetic flux branch and the total magnetic resistance of the middle column magnetic flux branch; A is the total magnetic resistance parameter of the first side column; B is the total magnetic resistance parameter of the second side column; C is the total magnetic resistance parameter of the third side column; D is the total magnetic resistance parameter of the first middle column; E is the total magnetic resistance parameter of the second middle column; F is the total magnetic resistance parameter of the third middle column; G is the total magnetic resistance parameter of the fourth middle column; H is the total magnetic resistance parameter of the fifth middle column.

[0143] Step 104: Determine the precise middle column air gap length according to the total magnetic resistance of the middle column magnetic flux branch and the geometric parameters of the magnetic core structure.

[0144] It should be noted that the magnetic resistance of the middle column magnetic flux branch is controlled by opening an air gap in the middle column magnetic flux branch. The magnetic resistivity of the air gap is much greater than that of the magnetic core. Therefore, although the length of the air gap is small, the magnetic field strength of the air gap is much greater than that of the magnetic core. The magnetic pressure drop on the air gap is large, resulting in a large magnetic potential difference at both ends of the air gap. The large magnetic potential difference will cause part of the magnetic flux to diffuse out of the core and flow in the air around the air gap, forming edge flux. The existence of the air gap edge flux will cause a large error in the calculation of the air gap magnetic resistance, which will bring difficulties to the control of the total magnetic resistance of the middle column magnetic flux branch and affect the design accuracy of the leakage inductance of the final design of the transformer.

[0145] For further information, see Figure 6 The equivalent model of the edge flux near the middle column air gap is as follows: Figure 6 As shown, the air gap length is , the extension width of the edge flux on the side surface of the core column is m, and the extension width is set to 3 times the air gap length, that is, , the magnetic field line shape of the edge flux is set to 1 / 4 ellipse + straight line + 1 / 4 ellipse, the ratio of the major and minor axes of the ellipse is 2:1, and the surface area of ​​the edge flux on the front and rear side surfaces of the core column is , the surface area on the left and right surfaces is .

[0146] The shortest path of the edge flux on the side surface , the longest path It can be expressed as formula (4-8):

[0147] (4-8)

[0148] The length coefficient K calculated by formula (4-9) is:

[0149] (4-9)

[0150] The surface area of ​​the edge flux on the front and rear side surfaces The area equivalent to the air gap cross section is , Surface area on the left and right surfaces The area equivalent to the air gap cross section is , expression (4-10) is as follows:

[0151] (4-10)

[0152] Calculation Considering the air gap edge flux, the air gap length is The magnetic resistance of the air gap It can be expressed as formula (4-11):

[0153] (4-11)

[0154] in, is the magnetic permeability of air.

[0155] Formula (4-12) calculates the magnetic resistance of the core magnetic circuit in the center column magnetic flux branch :

[0156] (4-12)

[0157] The total magnetic resistance of the central column magnetic flux branch is obtained by sorting The expression (4-13):

[0158] (4-13)

[0159] in, is the magnetic permeability of the core material of the EE type core used.

[0160] Based on the above foundation, the total magnetic resistance of the middle column magnetic flux branch is finally derived when the air gap edge flux effect and the magnetic resistance of the middle column magnetic core magnetic circuit are considered. The corresponding exact center column air gap length The expression (4-14):

[0161] (4-14)

[0162] Among them, the total magnetic resistance of the middle column magnetic flux branch, the height of the core window in the core structure geometric parameters, the width of the core middle column, and the thickness of the core are substituted into formula (4-14). The precise middle column air gap length is calculated; a is the first precise middle column air gap length parameter; b is the second precise middle column air gap length parameter; c is the third precise middle column air gap length parameter; d is the fourth precise middle column air gap length parameter.

[0163] Step 105: Calculate the magnetic resistance at the corners of the left and right side columns of the magnetic core using a preset magnetic core corner model according to the magnetic core structure geometric parameters and the magnetic flux branch magnetic flux.

[0164] The preset core corner model includes a left-side column core corner model and a right-side column core corner model.

[0165] The magnetic resistance at the corners of the left and right side column magnetic cores includes the magnetic resistance at the corner of the left side column magnetic core and the magnetic resistance at the corner of the right side column magnetic core.

[0166] It should be noted that at the corners of the magnetic core of the side column flux branch, since the magnetic flux tends to flow in the path with the smallest magnetic resistance, that is, the shortest path, the magnetic flux is mainly concentrated at the inner corners. When the magnetic flux density at the inner corners is close to saturation, the magnetic resistance at the inner corners increases significantly, and the magnetic flux will flow from a larger corner radius. Therefore, the magnetic flux density distribution at the corners of the magnetic core is uneven, and the magnetic core material exhibits different magnetic permeabilities under different magnetic flux densities. If the uneven distribution of magnetic flux at the corners is not considered, it will cause a large error in the calculation of the magnetic resistance at the corners of the magnetic core, which will affect the design accuracy of the leakage inductance of the final designed transformer.

[0167] Specifically, step 105 may include the following sub-steps S51-S55:

[0168] Step S51, using the width of the core side column in the core structure geometric parameters to divide the left side column core corner model and the right side column core corner model respectively, and determine the first core corner area, the second core corner area, the third core corner area and the core window inner corner area corresponding to the left side column core corner model and the right side column core corner model;

[0169] Step S52, using the magnetic flux of the left side column magnetic flux branch, the width of the core side column in the core structure geometric parameters, and the thickness of the core to perform magnetic resistance calculation on the first core corner area, the second core corner area, the third core corner area, and the corner area inside the core window corresponding to the left side column core corner model, to determine the magnetic resistance of the first core corner area, the second core corner area, the third core corner area, and the corner area inside the core window corresponding to the left side column core corner model;

[0170] Step S53, the magnetic resistance of the first magnetic core corner area, the magnetic resistance of the second magnetic core corner area, the magnetic resistance of the third magnetic core corner area and the magnetic resistance of the corner area in the core window corresponding to the left side column magnetic core corner model are connected in parallel to determine the magnetic resistance at the left side column magnetic core corner;

[0171] Step S54, using the magnetic flux of the right side column magnetic flux branch, the width of the core side column in the core structure geometric parameters, and the thickness of the core to perform magnetic resistance calculation on the first core corner area, the second core corner area, the third core corner area, and the corner area inside the core window corresponding to the right side column core corner model, to determine the magnetic resistance of the first core corner area, the second core corner area, the third core corner area, and the corner area inside the core window corresponding to the right side column core corner model;

[0172] Step S55, the magnetic resistance of the first core corner area, the magnetic resistance of the second core corner area, the magnetic resistance of the third core corner area and the magnetic resistance of the corner area in the core window corresponding to the right side column core corner model are connected in parallel to determine the magnetic resistance at the right side column core corner.

[0173] Please note that Figure 7 , establish a model for the corner of the transformer core, consider the uneven distribution of magnetic flux, and divide the magnetic flux at the corner of the core into five parts. The specific situation is as follows Figure 7 As shown, the length of the corner side (i.e. the width of the core side column) of and A quarter arc is made at the corner, thereby dividing the corner into a quarter circle and two quarter rings and the remaining parts, which are respectively recorded as the first core corner area , the second core corner area , the third core corner area and the fourth core corner region , at the inner corner of the core window Make a quarter arc to get a quarter circle, which is recorded as the corner area inside the core window. ,set up , , and The magnetic fluxes flowing in are , , and , The magnetic flux in is negligible, where is the size of the magnetic flux of the side column magnetic flux branch, that is, the magnetic flux branch magnetic flux. This step uses the magnetic flux of the left side column magnetic flux branch and the magnetic flux of the right side column magnetic flux branch in the magnetic flux branch to perform calculations.

[0174] Furthermore, taking the geometric midline as the magnetic path length, we obtain the expression (4-15) for the cross-sectional area and magnetic path length of each region, where: , , , for , , and The cross-sectional area of ​​each region, , , , for , , and Magnetic path length in each area:

[0175] (4-15)

[0176] Calculate , , The magnitude of magnetic flux density in each region (4-16):

[0177] (4-16)

[0178] According to the BH curve of the core material used, we can get , , The accurate magnetic permeability of each region under different magnetic flux density , and , that is, formula (4-17), where It is the function of magnetic permeability obtained from the BH curve of the core material with respect to magnetic flux density.

[0179] (4-17)

[0180] get , , , The magnetic resistance expression of the and region (4-18):

[0181] (4-18)

[0182] in, for The area under the corresponding magnetic flux density The accurate magnetic permeability of for The area under the corresponding magnetic flux density The accurate magnetic permeability of for The area under the corresponding magnetic flux density The accurate magnetic permeability of is the magnetic permeability of air.

[0183] Finally, the total magnetic resistance at the corner of the core is obtained by connecting the magnetic resistance of each area in parallel. (4-19):

[0184] (4-19)

[0185] Based on the above steps, the magnetic resistance at the corner of the left side column core is calculated respectively. And the magnetic resistance at the corner of the right side column core .

[0186] Step 106: Determine the magnetic resistance of the left and right magnetic powder core columns and the magnetic permeability of the magnetic powder core materials of the left and right magnetic powder core columns based on the magnetic core structure geometric parameters, the lengths of the left and right magnetic powder core columns, the magnetic flux of the magnetic flux branch, and the total magnetic resistance of the side column magnetic flux branch.

[0187] The magnetic resistance of the left and right magnetic powder core columns includes the magnetic resistance of the left magnetic powder core column and the magnetic resistance of the right magnetic powder core column.

[0188] The magnetic permeabilities of the magnetic powder core materials of the left and right magnetic powder core columns include the magnetic permeabilities of the magnetic powder core materials of the left magnetic powder core column and the magnetic permeabilities of the magnetic powder core materials of the right magnetic powder core column.

[0189] Specifically, step 106 may include the following sub-steps S61-S65:

[0190] Step S61, using the length of the left magnetic powder core column, the length of the right magnetic powder core column, the magnetic flux of the magnetic flux branch, the width of the core window in the core structure geometric parameters, the height of the core window, the width of the core side column, and the thickness of the core, calculate the magnetic resistance of the left residual core magnetic circuit and the magnetic resistance of the right residual core magnetic circuit;

[0191] Step S62, calculating the magnetic resistance of the left magnetic powder core magnetic column according to the magnetic resistance of the left residual magnetic core magnetic circuit and the total magnetic resistance of the side column magnetic flux branch;

[0192] Step S63, calculating the magnetic resistance of the magnetic powder core column on the right side according to the magnetic resistance of the remaining magnetic core magnetic circuit on the right side and the total magnetic resistance of the side column magnetic flux branch;

[0193] Step S64, calculating the magnetic permeability of the magnetic powder core material of the left magnetic powder core column based on the magnetic resistance of the left magnetic powder core column, the length of the left magnetic powder core column, the width of the magnetic core side column in the magnetic core structure geometric parameters, and the thickness of the magnetic core;

[0194] Step S65, calculating the magnetic permeability of the magnetic powder core material of the right magnetic powder core column based on the magnetic resistance of the right magnetic powder core column, the length of the right magnetic powder core column, the width of the core side column in the core structure geometric parameters, and the thickness of the core.

[0195] It should be noted that the total magnetic resistance of the side column flux branch is composed of three parts in series: the magnetic resistance of the magnetic powder core column, the magnetic resistance at the two core corners, and the magnetic resistance of the remaining core magnetic circuit after deducting the above two parts.

[0196] First, calculate the magnetic resistance of the left side column magnetic flux branch and the right side column magnetic flux branch after subtracting the magnetic powder core column and the two core corners (4-20):

[0197] (4-20)

[0198] The magnetic flux of the left column flux branch obtained by formula (4-2) , the magnetic flux of the right side column flux branch , combined with the cross-sectional area of ​​the side column ( ), the magnetic flux density of the left side column magnetic flux branch can be calculated and the flux density of the right column flux branch :Right now .

[0199] in, and According to the BH curve of the core material, when the magnetic flux density is and The accurate magnetic permeability under the condition is given by formula (4-21), where: It is the function of magnetic permeability obtained from the BH curve of the core material with respect to magnetic flux density.

[0200] (4-21)

[0201] The total magnetic resistance of the side column flux branch Subtract the reluctance of the two core corners and the reluctance of the remaining core magnetic circuit to obtain the reluctance of the left powder core column And the magnetic resistance of the right magnetic powder core column Size (4-22):

[0202] (4-22)

[0203] Calculate the magnetic permeability of the powder core material of the left powder core column and the right powder core column (4-23):

[0204] (4-23)

[0205] Step 107, determine the primary leakage inductance in the target magnetic core magnetic circuit, the additional leakage inductance in the air near the target winding coil, and the magnetic permeability of the magnetic powder core material of the target left and right magnetic powder core columns based on the total magnetic resistance of the side column magnetic flux branch, the geometric parameters of the magnetic core structure, the total magnetic resistance of the middle column magnetic flux branch, the magnetic flux of the magnetic flux branch, the magnetic resistance of the left and right magnetic powder core columns, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the transformer design parameters, the length of the left and right magnetic powder core columns, the electrical isolation distance between the left and right inner and outer coils, the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns, and the preset design leakage inductance.

[0206] It should be noted that there is a large magnetic potential difference at both ends of the magnetic powder core magnetic column surrounded by the winding coil, which will cause part of the magnetic flux to diffuse out of the magnetic core and form a loop in the air. This part of the magnetic flux does not completely link the primary winding coil and the secondary winding coil. According to the definition of leakage inductance, it is leakage inductance flux, which will bring additional leakage inductance. If the leakage magnetic field energy in the air near the winding coil is not considered, it will affect the design accuracy of the leakage inductance of the final designed transformer.

[0207] Specifically, step 107 may include the following sub-step S71:

[0208] Step S71, using the magnetic resistance of the left and right magnetic powder core columns, the magnetic flux of the magnetic flux branch, the number of turns of the original secondary winding coils allocated to the left and right side columns, the length of the left and right magnetic powder core columns, the electrical isolation distance between the left and right inner and outer coils, the core structure geometric parameters and the transformer design parameters, calculate the additional leakage inductance in the air near the initial winding coil;

[0209] Further, step S71 may include the following sub-steps S711-S715:

[0210] Step S711, using the magnetic resistance of the left and right magnetic powder core columns and the magnetic flux of the magnetic flux branch, calculate the magnetic voltage drop at both ends of the left and right magnetic powder core columns;

[0211] Step S712, according to the magnetic voltage drop at both ends of the left and right magnetic powder core columns, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the length of the left and right magnetic powder core columns, the electrical isolation distance between the left and right inner and outer coils, and the transformer design parameters, calculate the magnetic field strength in the primary winding coils of the left and right side columns, the magnetic field strength in the electrical isolation layer of the left and right side columns, and the magnetic field strength in the secondary winding coils of the left and right side columns;

[0212] Step S713, using the magnetic field strength in the primary winding coils of the left and right side columns, the magnetic field strength in the electrical isolation layer of the left and right side columns, the magnetic field strength in the secondary winding coils of the left and right side columns, and the geometric parameters of the magnetic core structure, calculate the total air leakage inductance energy of the winding coils of the left and right side columns;

[0213] Step S714, based on the total air leakage inductance energy of the left and right side column winding coils and the transformer design parameters, determine the primary leakage inductance on the left side column and the primary leakage inductance on the right side column;

[0214] Step S715: Add the primary leakage inductance on the left side column and the primary leakage inductance on the right side column to determine the additional leakage inductance in the air near the initial winding coil.

[0215] The magnetic field strength in the primary winding coils of the left and right side columns includes the magnetic field strength in the primary winding coil of the left side column and the magnetic field strength in the primary winding coil of the right side column.

[0216] The magnetic field strength in the electrical isolation layer of the left and right side pillars includes the magnetic field strength in the electrical isolation layer of the left side pillar and the magnetic field strength in the electrical isolation layer of the right side pillar.

[0217] The magnetic field strength in the secondary winding coils of the left and right side columns includes the magnetic field strength in the secondary winding coil of the left side column and the magnetic field strength in the secondary winding coil of the right side column.

[0218] The total leakage inductance energy of the air of the left and right side column winding coils includes the total leakage inductance energy in the air near the left side column winding coil and the total leakage inductance energy in the air near the right side column winding coil.

[0219] It should be noted that the additional leakage inductance in the air is calculated by considering the leakage magnetic field energy in the air near the winding coil. Specifically, the magnetic voltage drop at both ends of the left and right magnetic powder core columns is first calculated. The magnetic voltage drop at both ends of the left magnetic powder core column includes the magnetic voltage drop at both ends of the left magnetic powder core column. And the magnetic voltage drop at both ends of the magnetic powder core column on the right (4-24):

[0220] (4-24)

[0221] For further information, see Figure 8 , simplify the transformer structure, the structure diagram of the left side column and winding coil is as follows Figure 8 As shown, the lengths of the primary winding coil, the secondary winding coil and the magnetic powder core column are equal. , the wire width of the primary winding coil is , the wire width of the secondary winding coil is , the electrical isolation distance between the primary winding coil and the secondary winding coil is .

[0222] Taking the side surface of the core as the reference point, define x as the distance from the side surface of the core. According to Ampere's loop law, the magnetic field intensity in the primary winding coil of the left side column can be calculated as the distance x increases. , magnetic field strength in the electrical isolation layer of the left column , the magnetic field strength in the secondary winding coil of the left side column The expression that changes with distance x is (4-25):

[0223] (4-25)

[0224] According to the magnetic field energy formula, the magnetic field strength is integrated to obtain the leakage inductance energy stored in the primary winding coil of the left side column. , leakage inductance energy in the electrical isolation layer , leakage inductance energy in the secondary winding coil and the total leakage inductance energy in the air near the left side column winding coil (4-26):

[0225] (4-26)

[0226] According to the relationship between magnetic field energy and inductance, calculate the primary leakage inductance on the left side column (4-27):

[0227] (4-27)

[0228] It is worth mentioning that based on the above steps and principles for calculating the primary leakage inductance on the left side column, the primary leakage inductance on the right side column can be calculated .

[0229] Furthermore, the primary leakage inductance on the left side column and the primary leakage inductance on the right side column are added together to finally obtain the total additional primary leakage inductance in the air (i.e., the additional leakage inductance in the air near the initial winding coil). (4-28):

[0230] (4-28)

[0231] Step S72, determining the primary leakage inductance in the initial magnetic core magnetic circuit based on the preset design leakage inductance;

[0232] It should be noted that the preset designed leakage inductance is used to initialize the primary leakage inductance in the magnetic core magnetic circuit, that is, the primary leakage inductance in the initial magnetic core magnetic circuit is equal to the preset designed leakage inductance.

[0233] Step S73, fine-tuning the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns, and determining the magnetic permeability of the magnetic powder core material of the middle left and right magnetic powder core columns;

[0234] Step S74, using the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns, the length of the left and right magnetic powder core columns, the width of the core side column in the transformer design parameters, and the thickness of the magnetic core to update the magnetic resistance of the left and right magnetic powder core columns, and determine the magnetic resistance of the left and right magnetic powder core columns in the middle;

[0235] Step S75, using the total magnetic resistance of the side column magnetic flux branch, the magnetic resistance of the left and right magnetic powder core magnetic columns in the middle, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, and the total magnetic resistance of the middle column magnetic flux branch to update the primary leakage inductance in the initial magnetic core magnetic circuit, and determine the primary leakage inductance in the middle magnetic core magnetic circuit;

[0236] Specifically, step S75 may include the following sub-steps:

[0237] Step S751, using the magnetic resistance of the left and right magnetic powder core magnetic columns in the middle to update the total magnetic resistance of the side column magnetic flux branch, to determine the total magnetic resistance of the middle side column magnetic flux branch;

[0238] Step S752, update the primary leakage inductance in the initial magnetic core magnetic circuit according to the total magnetic resistance of the middle side column magnetic flux branch, the number of primary and secondary winding coil turns allocated to the left and right side columns, and the total magnetic resistance of the middle column magnetic flux branch, and determine the primary leakage inductance in the middle magnetic core magnetic circuit.

[0239] It should be noted that, based on the above steps, the additional primary leakage inductance in the air is calculated. At this time, the sum of the leakage inductance in the magnetic core and the leakage inductance in the air is greater than the designed leakage inductance. The magnetic resistance of the side column flux branch should be modulated (by adjusting the magnetic permeability of the magnetic powder core magnetic column) to reduce the leakage inductance in the magnetic core, so that the sum of the leakage inductance in the magnetic core and the leakage inductance in the air is equal to the designed leakage inductance, thereby achieving precise control of the leakage inductance of the magnetic integrated transformer.

[0240] Further, the magnetic permeabilities of the left magnetic powder core column and the right magnetic powder core column are fine-tuned to obtain the magnetic permeabilities of the magnetic powder core materials of the left and right magnetic powder core columns in the middle. The magnetic permeabilities of the magnetic powder core materials of the left and right magnetic powder core columns in the middle include the updated magnetic permeabilities of the left magnetic powder core column (i.e., the magnetic permeabilities of the magnetic powder core materials of the left magnetic powder core column in the middle) and the right magnetic powder core column (i.e., the magnetic permeabilities of the magnetic powder core materials of the right magnetic powder core column in the middle), respectively. and The fine-tuning method is to subtract the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns from the set threshold.

[0241] The magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns in the middle, the length of the left and right magnetic powder core columns, the width of the core side columns in the transformer design parameters, and the thickness of the core are used to calculate the magnetic resistance of the left and right magnetic powder core columns in the middle. The magnetic resistance of the left and right magnetic powder core columns in the middle includes the updated magnetic resistance of the left magnetic powder core column (that is, the magnetic resistance of the left magnetic powder core column in the middle) And the magnetic resistance of the right magnetic powder core column (that is, the magnetic resistance of the right magnetic powder core column in the middle) (4-29):

[0242] (4-29)

[0243] The total magnetic resistance of the middle side column flux branch is calculated by using the magnetic resistance of the left and right side magnetic powder core columns, that is, the updated total magnetic resistance of the side column flux branch (4-30):

[0244] (4-30)

[0245] Finally, according to the total magnetic resistance of the middle column magnetic flux branch, the number of turns of the primary and secondary windings allocated to the left and right columns, and the total magnetic resistance of the middle column magnetic flux branch, the primary leakage inductance in the middle core magnetic circuit is calculated, that is, the primary leakage inductance in the updated core magnetic circuit (4-31):

[0246] (4-31)

[0247] Step S76, updating the additional leakage inductance in the air near the initial winding coil based on the magnetic resistance of the magnetic powder core columns on the left and right sides of the middle, and determining the additional leakage inductance in the air near the middle winding coil;

[0248] It should be noted that, by combining equations (4-24) to (4-28), the additional leakage inductance in the air near the middle winding coil is calculated based on the magnetic resistance of the magnetic powder core columns on the left and right sides of the middle, that is, the updated additional primary leakage inductance in the air .

[0249] Step S77, determining whether the sum of the additional leakage inductance in the air near the middle winding coil and the primary leakage inductance in the middle magnetic core magnetic circuit is equal to the preset design leakage inductance;

[0250] Step S78, if yes, then the additional leakage inductance in the air near the middle winding coil is used as the additional leakage inductance in the air near the target winding coil, the primary leakage inductance in the middle magnetic core magnetic circuit is used as the primary leakage inductance in the target magnetic core magnetic circuit, and the magnetic permeability of the magnetic powder core material of the middle left and right magnetic powder core columns is used as the magnetic permeability of the magnetic powder core material of the target left and right magnetic powder core columns.

[0251] It should be noted that if the sum of the additional leakage inductance in the air near the middle winding coil and the primary leakage inductance in the middle magnetic core magnetic circuit is not equal to the preset design leakage inductance, the magnetic permeability of the magnetic powder core material of the middle left and right magnetic powder core columns is used as the new magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns, the magnetic resistance of the middle left and right magnetic powder core columns is used as the new magnetic resistance of the left and right magnetic powder core columns, the primary leakage inductance in the middle magnetic core magnetic circuit is used as the new primary leakage inductance in the initial magnetic core magnetic circuit, the additional leakage inductance in the air near the middle winding coil is used as the new additional leakage inductance in the air near the initial winding coil, and the execution step is jumped. S73, until the sum of the additional leakage inductance in the air near the middle winding coil and the primary leakage inductance in the middle magnetic core magnetic circuit is equal to the preset design leakage inductance, the additional leakage inductance in the air near the middle winding coil determined when the sum of the additional leakage inductance in the air near the middle winding coil and the primary leakage inductance in the middle magnetic core magnetic circuit is equal to the preset design leakage inductance is used as the additional leakage inductance in the air near the target winding coil, the primary leakage inductance in the middle magnetic core magnetic circuit is used as the primary leakage inductance in the target magnetic core magnetic circuit, and the magnetic permeability of the magnetic powder core material of the middle left and right magnetic powder core columns is used as the magnetic permeability of the magnetic powder core material of the target left and right magnetic powder core columns.

[0252] Step 108, based on the preset coil winding method, the magnetic integrated transformer for the CLLC converter is designed through the sum of the primary leakage inductance in the target core magnetic circuit and the additional leakage inductance in the air near the target winding coil, the length of the left and right magnetic powder core columns, the precise middle column air gap length, and the magnetic permeability of the magnetic powder core material of the target left and right magnetic powder core columns.

[0253] The preset coil winding method is to compare the primary winding coil and the secondary winding coil on the left side column. Under the tight winding, the coil with the larger coil width is wound in the inner layer. The winding method is tight winding, and the winding coil width is The coil with smaller coil width is wound on the outer layer, and the winding method is uniform winding. The coil width is also equal to , so that the primary winding coil and the secondary winding coil on the left side column are of equal length; and compare the primary winding coil and the secondary winding coil on the right side column. The coil with the larger coil width is wound in the inner layer under tight winding. The winding method is tight winding, and the winding coil width is The coil with smaller coil width is wound on the outer layer, and the winding method is uniform winding. The coil width is also equal to , so that the primary winding coil and the secondary winding coil on the right side column are of equal length.

[0254] It should be noted that, based on the preset coil winding method, the design of the magnetic integrated transformer for CLLC converter is completed through the sum of the primary leakage inductance in the target core magnetic circuit and the additional leakage inductance in the air near the target winding coil, the length of the left and right side magnetic powder core magnetic columns, the precise middle column air gap length, and the magnetic permeability of the magnetic powder core material of the target left and right side magnetic powder core magnetic columns.

[0255] As a comparison of technical effects, it can be combined with the existing technology for reference. The working principle of the existing leakage inductance integration scheme is to distribute the primary winding and the secondary winding of the transformer to the two side columns unequally, which will generate a magnetic potential difference at both ends of the middle column. By adjusting the air gap magnetic resistance of the middle column and the two side columns, the size of the magnetic flux flowing through the middle column can be controlled. According to the definition of leakage inductance, the middle column magnetic flux constitutes the leakage inductance flux. Therefore, by adjusting the size of the air gap between the middle column and the side column of the magnetic core and the number of primary and secondary windings on the two side columns of the magnetic core, the size of the leakage inductance can be controlled. However, although this method can control the size of the leakage inductance, the deviation between the theoretical derivation results and the actual parameters is large, with a large error, and it is impossible to achieve accurate control of the leakage inductance. The reason is that the leakage flux in the air and the edge effect of the air gap are ignored, and the magnetic permeability of the magnetic core is considered to be infinite and the size of the magnetic resistance in the magnetic circuit of the magnetic core is ignored.

[0256] Therefore, how to accurately model the air leakage flux, air gap edge effect and magnetic core magnetic circuit reluctance, and then fully consider their influence on the transformer leakage inductance, so as to achieve precise control of the leakage inductance of the magnetic integrated transformer of the CLLC converter is a problem to be solved.

[0257] In view of the above problems, the present invention proposes a design method for a magnetic integrated transformer for a CLLC converter, which fully considers the leakage flux in the air, the edge effect of the air gap and the magnetic resistance of the magnetic core magnetic circuit, and proposes a design method for a magnetic integrated transformer for a CLLC converter with accurately controllable leakage inductance (using a magnetic powder core column with the same length as the winding coil to replace the air gap, and accurately controlling the total leakage inductance of the magnetic integrated transformer to be equal to the design value by controlling the magnetic permeability of the magnetic powder core column material), solving the problem of large design leakage inductance error and low precision. At the same time, by placing a magnetic powder core column with the same length as the winding coil in the side column magnetic flux branch, the magnetic resistance of the magnetic powder core column is equivalent to the internal resistance of the magnetic potential of the winding coil, so that most of the magnetic potential of the winding coil falls on the magnetic powder core column, reducing the magnetic potential difference at both ends of the magnetic powder core column and the leakage flux in the air, and further reducing the eddy current loss of the winding coil. In addition, by winding the primary winding coil and the secondary winding coil on the side column with equal length and placing a magnetic powder core column with the same length as the winding coil, the leakage flux distribution shape in the air near the air gap is made more regular, reducing the difficulty of modeling and analyzing the leakage flux in the air, which is conducive to calculating the magnitude of the leakage inductance in the air.

[0258] Compared with the prior art, the traditional CLLC converter adopts a discrete magnetic component solution, that is, an independent resonant inductor is connected in series with an independent transformer. This solution has the problems of large magnetic component volume, low power density, large number of components and high cost. Therefore, the present invention proposes a magnetic integration design method, which combines the resonant inductor and the transformer by using the leakage inductance of the converter as the resonant inductor, thereby eliminating the independent resonant inductor, and has the advantages of small magnetic component volume, high power density, small number of components and low cost.

[0259] Secondly, as a component participating in resonance, the size of the inductance of the resonant inductor directly affects the accuracy of the resonant frequency of the resonant converter, and further affects the parameter design of the entire converter. Therefore, it is expected that the leakage inductance of the transformer can be controlled to obtain a more accurate inductance. Therefore, the present invention proposes a magnetic integration design method in which the leakage inductance can be accurately controlled. First, an accurate magnetic core magnetic circuit model and an air leakage inductance model are established, and then the accurate transformer leakage inductance is calculated according to the model, thereby achieving accurate control of the leakage inductance.

[0260] Thirdly, the design method of a magnetic integrated transformer for a CLLC converter proposed in the present invention solves the problem of numerous design parameters and high design difficulty of magnetic components.

[0261] In an embodiment of the present invention, the present invention provides a magnetic integrated transformer design method for a CLLC converter. First, the transformer design parameters are obtained, and the total number of turns of the primary and secondary winding coils, the core model, and the core structure geometric parameters corresponding to the core model are determined according to the transformer design parameters by using a preset area product method; then, the number of turns of the primary and secondary winding coils assigned to the left and right side columns, the length of the left and right side magnetic powder core magnetic columns, and the electrical isolation distance between the left and right inner and outer coils are determined according to the transformer design parameters by using preset constraints; the number of turns of the primary and secondary winding coils assigned to the left and right side columns is determined by using a preset transformer magnetic circuit model. , the total number of turns of the primary and secondary winding coils and the design parameters of the transformer, calculate the magnetic flux of the flux branch, the total magnetic resistance of the side column magnetic flux branch and the total magnetic resistance of the middle column magnetic flux branch; determine the precise middle column air gap length based on the total magnetic resistance of the middle column magnetic flux branch and the geometric parameters of the core structure; use the preset core corner model to calculate the magnetic resistance at the corners of the left and right side column cores according to the core structure geometric parameters and the magnetic flux of the flux branch; determine the magnetic resistance of the left and right side powder core columns and the magnetic permeability of the powder core material of the left and right side powder core columns based on the core structure geometric parameters, the length of the left and right side powder core columns, the magnetic flux branch and the total magnetic resistance of the side column magnetic flux branch; determine the magnetic resistance of the left and right side powder core columns and the magnetic permeability of the powder core material of the left and right side powder core columns based on the side column magnetic flux branch The total magnetic resistance, geometric parameters of the magnetic core structure, the total magnetic resistance of the middle column magnetic flux branch, the magnetic flux of the magnetic flux branch, the magnetic resistance of the left and right magnetic powder core columns, the number of turns of the primary and secondary winding coils assigned to the left and right side columns, the transformer design parameters, the length of the left and right magnetic powder core columns, the electrical isolation distance between the left and right inner and outer coils, the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns and the preset design leakage inductance are used to determine the primary leakage inductance in the target magnetic core magnetic circuit, the additional leakage inductance in the air near the target winding coil and the magnetic permeability of the magnetic powder core material of the target left and right magnetic powder core columns; finally, based on the preset coil winding method, the primary leakage inductance in the target magnetic core magnetic circuit and the target winding are used to determine the primary leakage inductance in the target magnetic core magnetic circuit and the target winding The sum of the extra leakage inductance in the air near the winding coil, the length of the left and right magnetic powder core columns, the precise middle column air gap length, and the magnetic permeability of the magnetic powder core materials of the target left and right magnetic powder core columns are used to design a magnetic integrated transformer for the CLLC converter; based on the above scheme, the present invention combines the preset coil winding method and the equal length of the left and right magnetic powder core columns to make the leakage flux distribution in the air near the winding coil more regular. At the same time, the core corner, the precise middle column air gap length, and the extra leakage inductance of the air are taken into consideration, thereby achieving precise control of the transformer leakage inductance, thereby improving the design accuracy of the magnetic integrated transformer for the CLLC converter.

[0262] For better explanation, refer to Fig. 9, showing a flow chart of a magnetic integrated transformer design method for a CLLC converter provided by Embodiment 2 of the present invention. It should be pointed out that this embodiment only briefly describes the general process of the magnetic integrated transformer design method for a CLLC converter, and the specific implementation process of each step can be understood by referring to the relevant content in the aforementioned embodiment, which will not be described here. It can be understood that the present invention is not limited to this.

[0263] Step 1: Obtain the design parameters of the transformer, calculate the magnetic core and winding coil according to the AP method, and obtain the structural geometric parameters of the magnetic core and the parameters of the winding coil.

[0264] Step 2: Calculate the number of turns of the primary and secondary winding coils allocated to the left and right side columns, design the winding method of the coil, and obtain the length of the magnetic powder core column that is equal to the length of the coil.

[0265] Step 3: Calculate the total magnetic resistance of the side column magnetic flux branches and the total magnetic resistance of the middle column magnetic flux branch.

[0266] Step 4: Consider the edge flux effect of the center column air gap and calculate the exact air gap size of the center column of the magnetic core.

[0267] Step 5: Considering the uneven distribution of magnetic flux at the corners of the core, calculate the precise magnetic resistance at the corners of the core.

[0268] Step 6: Subtract the magnetic resistance of the core magnetic circuit from the total magnetic resistance of the side column magnetic flux branch to obtain the magnetic resistance of the magnetic powder core column, and calculate the magnetic permeability of the magnetic powder core material of the magnetic powder core column.

[0269] Step 7: Consider the leakage magnetic field energy in the air near the winding coil and calculate the leakage inductance in the air.

[0270] Step 8: Fine-tune the magnetic permeability of the magnetic powder core material and perform iterative calculations repeatedly until the sum of the leakage inductance in the core and the leakage inductance in the air is equal to the designed leakage inductance.

[0271] In an embodiment of the present invention, the present invention proposes a magnetic integrated transformer design method for a CLLC converter, which can accurately control the leakage inductance of the magnetic integrated transformer, so that the leakage inductance of the transformer acts as a resonant inductor to achieve magnetic integration. Specifically, the optimal number of turns distribution method of the primary and secondary winding coils on the left side column and the right side column is derived in step 2. At the same time, in step S2, the winding method of the primary and secondary winding coils, that is, the inner layer is tightly wound and the outer layer is evenly wound, so that the lengths of the primary and secondary winding coils are equal; magnetic powder core magnetic columns of the same length as the winding coils are placed to control the magnetic resistance of the magnetic flux branch; the winding method of the coil and the magnetic powder core magnetic columns of equal length make the leakage magnetic flux distribution in the space near the winding coil more regular, which is conducive to modeling and calculating the leakage inductance in the air. In step S3, the total magnetic resistance of the left and right side column magnetic flux branches is derived. and the total magnetic resistance of the center column flux branch In step S4, the air gap length is controlled to control the total magnetic resistance of the middle column magnetic flux branch. Considering the air gap edge flux, the precise air gap length is derived. In step S5, considering the uneven distribution of magnetic flux at the corners of the core, a local model of the core corners is established to calculate the precise magnetic resistance at the corners of the core. In steps S7 and S8, a leakage magnetic energy model near the winding coil is established to calculate the leakage inductance in the air, fine-tune the magnetic permeability of the magnetic powder core column, and iterate the calculation repeatedly until the sum of the leakage inductance in the core magnetic circuit and the leakage inductance in the air is equal to the designed leakage inductance.

[0272] Compared with the existing technology, the present invention fully considers the edge flux near the air gap, the magnetic resistance of the core magnetic circuit, the uneven distribution at the corners of the core, and the leakage inductance in the air near the winding coil, and establishes a corresponding local model and derives a mathematical formula, thereby achieving precise control of the transformer leakage inductance. In comparison, the present invention improves the design accuracy.

[0273] By placing a magnetic powder core column with the same length as the winding coil in the side column flux branch, the magnetic resistance of the magnetic powder core column is made equivalent to the internal resistance of the magnetic potential of the winding coil, so that most of the magnetic potential of the winding coil falls on the magnetic powder core column, reducing the magnetic potential difference at both ends of the magnetic powder core column and the leakage flux in the air, and further reducing the eddy current loss of the winding coil.

[0274] See also Fig.10 , Fig.10 This is a structural block diagram of a magnetic integrated transformer design device for a CLLC converter provided in Embodiment 3 of the present invention.

[0275] The present invention provides a magnetic integrated transformer design device for a CLLC converter, comprising:

[0276] The acquisition module 1001 is used to acquire the transformer design parameters, and determine the total number of turns of the primary and secondary winding coils, the magnetic core model and the magnetic core structure geometric parameters corresponding to the magnetic core model according to the transformer design parameters by using a preset area product method;

[0277] The first calculation module 1002 is used to determine the number of turns of the primary and secondary windings allocated to the left and right side columns, the length of the left and right side magnetic powder core columns, and the electrical isolation distance between the left and right side inner and outer coils according to the transformer design parameters using preset constraints;

[0278] The second calculation module 1003 is used to calculate the magnetic flux of the magnetic flux branch, the total magnetic resistance of the side column magnetic flux branch and the total magnetic resistance of the middle column magnetic flux branch by using a preset transformer magnetic circuit model according to the turns of the primary and secondary winding coils allocated to the left and right side columns, the total turns of the primary and secondary winding coils and the transformer design parameters;

[0279] The third calculation module 1004 is used to determine the precise middle column air gap length according to the total magnetic resistance of the middle column magnetic flux branch and the geometric parameters of the magnetic core structure;

[0280] The fourth calculation module 1005 is used to calculate the magnetic resistance at the corners of the left and right side column magnetic cores according to the geometric parameters of the magnetic core structure and the magnetic flux of the magnetic flux branch by using a preset magnetic core corner model;

[0281] A fifth calculation module 1006 is used to determine the magnetic resistance of the left and right magnetic powder core columns and the magnetic permeability of the magnetic powder core materials of the left and right magnetic powder core columns based on the magnetic core structure geometric parameters, the lengths of the left and right magnetic powder core columns, the magnetic flux of the magnetic flux branch, and the total magnetic resistance of the side column magnetic flux branch;

[0282] Output target parameter module 1007, used for determining the primary leakage inductance in the target magnetic core magnetic circuit, the additional leakage inductance in the air near the target winding coil and the magnetic permeability of the magnetic powder core material of the target left and right magnetic powder core columns according to the total magnetic resistance of the side column magnetic flux branch, the geometric parameters of the magnetic core structure, the total magnetic resistance of the middle column magnetic flux branch, the magnetic flux of the magnetic flux branch, the magnetic resistance of the left and right magnetic powder core columns, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the transformer design parameters, the length of the left and right magnetic powder core columns, the electrical isolation distance between the left and right inner and outer coils, the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns and the preset design leakage inductance;

[0283] Design module 1008 is used to design a magnetic integrated transformer for a CLLC converter based on a preset coil winding method, through the sum of the primary leakage inductance in the target core magnetic circuit and the additional leakage inductance in the air near the target winding coil, the length of the left and right side magnetic powder core magnetic columns, the precise middle column air gap length, and the magnetic permeability of the magnetic powder core material of the target left and right side magnetic powder core magnetic columns.

[0284] Furthermore, preset constraints are as follows:

[0285] The product of the number of turns of the primary winding coil allocated to the left side column and the number of turns of the secondary winding coil is equal to the product of the number of turns of the primary winding coil allocated to the right side column and the number of turns of the secondary winding coil.

[0286] Further, the primary and secondary winding coil turns allocated to the left and right side columns include the primary winding coil turns of the left side column, the secondary winding coil turns of the left side column, the primary winding coil turns of the right side column, and the secondary winding coil turns of the right side column; the lengths of the left and right side magnetic powder core magnetic columns include the length of the left magnetic powder core magnetic column and the length of the right magnetic powder core magnetic column; the first calculation module 1002 is specifically used to:

[0287] The preset constraints are used to calculate the number of turns of the primary winding coil of the left side column, the number of turns of the secondary winding coil of the left side column, the number of turns of the primary winding coil of the right side column, and the number of turns of the secondary winding coil of the right side column according to the primary resonant inductance value and the secondary resonant inductance value in the transformer design parameters;

[0288] Based on the number of turns of the primary winding coil of the left side column and the number of turns of the secondary winding coil of the left side column, determine the width of the primary winding coil of the left side column and the width of the secondary winding coil of the left side column in the case of tight winding;

[0289] Compare the left side column primary winding coil width and the left side column secondary winding coil width in the case of tight winding;

[0290] The largest left-side column primary winding coil width or the left-side column secondary winding coil width is used as the target left-side column winding coil width, and based on the target left-side column winding coil width, the left-side magnetic powder core magnetic column length is determined;

[0291] Based on the number of turns of the primary winding coil of the right side column and the number of turns of the secondary winding coil of the right side column, determine the width of the primary winding coil of the right side column and the width of the secondary winding coil of the right side column in the case of tight winding;

[0292] Compare the right side leg primary winding coil width and the right side leg secondary winding coil width in the case of close winding;

[0293] The largest right-side column primary winding coil width or the right-side column secondary winding coil width is used as the target right-side column winding coil width, and based on the target right-side column winding coil width, the right-side magnetic powder core magnetic column length is determined;

[0294] According to the transformer input voltage and transformer output voltage in the transformer design parameters, calculate the electrical isolation distance between the inner and outer coils on the left and right sides.

[0295] Further, the second calculation module 1003 is specifically used for:

[0296] According to the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the primary resonant inductance value, the secondary resonant inductance value, the primary excitation inductance value of the transformer, and the total number of turns of the primary and secondary winding coils, the total magnetic resistance of the side column magnetic flux branch and the total magnetic resistance of the middle column magnetic flux branch are calculated;

[0297] The preset transformer magnetic circuit model is divided to generate a left side column magnetic flux branch, a right side column magnetic flux branch and a middle column magnetic flux branch;

[0298] The magnetic flux branch method is used to model the magnetic flux branch of the left side column, the magnetic flux branch of the right side column and the magnetic flux branch of the middle column, and a relationship equation group between the magnetic flux branch of the left side column, the magnetic flux branch of the right side column and the magnetic flux branch of the middle column is generated;

[0299] The magnetic flux of the magnetic flux branch is calculated by using the relationship equation group between the left side column magnetic flux branch, the right side column magnetic flux branch and the middle column magnetic flux branch according to the total magnetic resistance of the side column magnetic flux branch, the total magnetic resistance of the middle column magnetic flux branch, the total number of turns of the primary and secondary winding coils, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, and the primary winding coil current and the secondary winding coil current in the transformer design parameters;

[0300] The calculation formula corresponding to the total magnetic resistance of the side column magnetic flux branch and the total magnetic resistance of the middle column magnetic flux branch is specifically:

[0301] ;

[0302] Among them, A is the total magnetic resistance parameter of the first side column; B is the total magnetic resistance parameter of the second side column; C is the total magnetic resistance parameter of the third side column; D is the total magnetic resistance parameter of the first middle column; E is the total magnetic resistance parameter of the second middle column; F is the total magnetic resistance parameter of the third middle column; G is the total magnetic resistance parameter of the fourth middle column; H is the total magnetic resistance parameter of the fifth middle column; is the total magnetic resistance of the side column flux branch; is the total magnetic resistance of the center column flux branch; is the primary resonant inductance value; is the secondary side resonant inductance value; The number of turns of the primary winding coil assigned to the left side column; The number of turns of the secondary winding coil allocated to the left column; is the total number of turns of the secondary winding coil; is the total number of turns of the primary winding coil; The number of turns of the primary winding coil allocated to the right column; The number of turns of the secondary winding coil allocated to the right column; is the primary magnetizing inductance of the transformer.

[0303] Further, the magnetic flux of the magnetic flux branch includes the magnetic flux of the left side column magnetic flux branch and the magnetic flux of the right side column magnetic flux branch; the preset magnetic core corner model includes the left side column magnetic core corner model and the right side column magnetic core corner model; the magnetic resistance at the left and right side column magnetic core corners includes the magnetic resistance at the left side column magnetic core corner and the magnetic resistance at the right side column magnetic core corner; the fourth calculation module 1005 is specifically used to:

[0304] The left-side column magnetic core corner model and the right-side column magnetic core corner model are divided respectively by using the width of the magnetic core side column in the magnetic core structure geometric parameters, and the first magnetic core corner area, the second magnetic core corner area, the third magnetic core corner area and the corner area inside the magnetic core window corresponding to the left-side column magnetic core corner model and the right-side column magnetic core corner model are determined;

[0305] Using the magnetic flux of the left-side column magnetic flux branch, the width of the core side column in the core structure geometric parameters, and the thickness of the core, magnetic resistance calculations are performed on the first core corner area, the second core corner area, the third core corner area, and the corner area inside the core window corresponding to the left-side column core corner model to determine the magnetic resistance of the first core corner area, the second core corner area, the third core corner area, and the corner area inside the core window corresponding to the left-side column core corner model;

[0306] The magnetic resistance of the first magnetic core corner area, the magnetic resistance of the second magnetic core corner area, the magnetic resistance of the third magnetic core corner area and the magnetic resistance of the corner area in the core window corresponding to the left side column magnetic core corner model are connected in parallel to determine the magnetic resistance at the left side column magnetic core corner;

[0307] Using the magnetic flux of the right-side column magnetic flux branch, the width of the core side column in the core structure geometric parameters, and the thickness of the core, magnetic resistance calculations are performed on the first core corner area, the second core corner area, the third core corner area, and the corner area inside the core window corresponding to the right-side column core corner model to determine the magnetic resistance of the first core corner area, the second core corner area, the third core corner area, and the corner area inside the core window corresponding to the right-side column core corner model;

[0308] The magnetic resistance of the first core corner area, the second core corner area, the third core corner area and the corner area in the core window corresponding to the right side column core corner model are connected in parallel to determine the magnetic resistance at the right side column core corner.

[0309] Further, the magnetic resistance of the left and right magnetic powder core columns includes the magnetic resistance of the left magnetic powder core column and the magnetic resistance of the right magnetic powder core column; the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns includes the magnetic permeability of the magnetic powder core material of the left magnetic powder core column and the magnetic permeability of the magnetic powder core material of the right magnetic powder core column; the fifth calculation module 1006 is specifically used to:

[0310] The magnetic resistance of the left residual magnetic core magnetic circuit and the magnetic resistance of the right residual magnetic core magnetic circuit are calculated by using the magnetic column length of the left magnetic powder core, the magnetic flux of the magnetic flux branch, the width of the magnetic core window in the magnetic core structure geometric parameters, the height of the magnetic core window, the width of the magnetic core side column, and the thickness of the magnetic core;

[0311] Calculate the magnetic resistance of the left magnetic powder core column based on the magnetic resistance of the left residual core magnetic circuit and the total magnetic resistance of the side column magnetic flux branch;

[0312] According to the magnetic resistance of the right residual core magnetic circuit and the total magnetic resistance of the side column magnetic flux branch, calculate the magnetic resistance of the right magnetic powder core column;

[0313] Based on the magnetic resistance of the left magnetic powder core column, the length of the left magnetic powder core column, the width of the core side column in the core structure geometric parameters and the thickness of the core, the magnetic permeability of the magnetic powder core material of the left magnetic powder core column is calculated;

[0314] The magnetic permeability of the magnetic powder core material of the right magnetic powder core column is calculated based on the magnetic resistance of the right magnetic powder core column, the length of the right magnetic powder core column, the width of the core side column in the core structure geometric parameters, and the thickness of the core.

[0315] Furthermore, the target parameter output module 1007 includes:

[0316] The first submodule is used to calculate the additional leakage inductance in the air near the initial winding coil by using the magnetic resistance of the left and right magnetic powder core columns, the magnetic flux of the magnetic flux branch, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the length of the left and right magnetic powder core columns, the electrical isolation distance between the left and right inner and outer coils, the core structure geometric parameters and the transformer design parameters;

[0317] The second submodule is used to determine the primary leakage inductance in the initial magnetic core magnetic circuit based on the preset design leakage inductance;

[0318] The third submodule is used to fine-tune the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns, and determine the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns in the middle;

[0319] The fourth submodule is used to update the magnetic resistance of the left and right magnetic powder core columns by using the magnetic permeability of the magnetic powder core materials of the left and right magnetic powder core columns, the length of the left and right magnetic powder core columns, the width of the magnetic core side columns in the transformer design parameters, and the thickness of the magnetic core to determine the magnetic resistance of the left and right magnetic powder core columns in the middle;

[0320] The fifth submodule is used to update the primary leakage inductance in the initial magnetic core magnetic circuit by using the total magnetic resistance of the side column magnetic flux branch, the magnetic resistance of the left and right magnetic powder core magnetic columns in the middle, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, and the total magnetic resistance of the middle column magnetic flux branch to determine the primary leakage inductance in the middle magnetic core magnetic circuit;

[0321] The sixth submodule is used to update the additional leakage inductance in the air near the initial winding coil based on the magnetic resistance of the magnetic powder core columns on the left and right sides of the middle, and determine the additional leakage inductance in the air near the middle winding coil;

[0322] The seventh submodule is used to determine whether the sum of the additional leakage inductance in the air near the middle winding coil and the primary leakage inductance in the middle magnetic core magnetic circuit is equal to the preset design leakage inductance;

[0323] The eighth submodule is used to, if yes, use the additional leakage inductance in the air near the middle winding coil as the additional leakage inductance in the air near the target winding coil, use the primary leakage inductance in the middle magnetic core magnetic circuit as the primary leakage inductance in the target magnetic core magnetic circuit, and use the magnetic permeability of the magnetic powder core material of the middle left and right magnetic powder core columns as the magnetic permeability of the magnetic powder core material of the target left and right magnetic powder core columns.

[0324] Furthermore, the first submodule is specifically used for:

[0325] The magnetic resistance of the left and right magnetic powder core columns and the magnetic flux of the magnetic flux branch are used to calculate the magnetic voltage drop at both ends of the left and right magnetic powder core columns.

[0326] According to the magnetic voltage drop at both ends of the left and right magnetic powder core columns, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the length of the left and right magnetic powder core columns, the electrical isolation distance between the left and right inner and outer coils and the transformer design parameters, the magnetic field intensity in the primary winding coils of the left and right side columns, the magnetic field intensity in the electrical isolation layer of the left and right side columns and the magnetic field intensity in the secondary winding coils of the left and right side columns are calculated;

[0327] The total air leakage inductance energy of the left and right side column winding coils is calculated by using the magnetic field intensity in the primary winding coils of the left and right side columns, the magnetic field intensity in the electrical isolation layer of the left and right side columns, the magnetic field intensity in the secondary winding coils of the left and right side columns and the geometric parameters of the magnetic core structure;

[0328] Based on the total air leakage inductance energy of the left and right side column winding coils and the transformer design parameters, determine the primary leakage inductance on the left side column and the primary leakage inductance on the right side column;

[0329] The additional leakage inductance in the air near the initial winding coil is determined by adding the primary leakage inductance on the left side column and the primary leakage inductance on the right side column.

[0330] Furthermore, the precise length of the air gap in the center column is:

[0331] ;

[0332] in, is the precise center column air gap length; is the total magnetic resistance of the middle column magnetic flux branch; a is the first accurate middle column air gap length parameter; b is the second accurate middle column air gap length parameter; c is the third accurate middle column air gap length parameter; d is the fourth accurate middle column air gap length parameter; is the height of the core window; is the width of the core column; is the thickness of the magnetic core; is the magnetic permeability of the core material of the EE type core used; is the magnetic permeability of air.

[0333] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices, modules and sub-modules can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0334] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A magnetic integrated transformer design method for a CLLC converter, characterized in that: include: Obtaining transformer design parameters, and using a preset area product method to determine the total number of turns of the primary and secondary winding coils, the magnetic core model, and the magnetic core structure geometric parameters corresponding to the magnetic core model according to the transformer design parameters; Using preset constraints, according to the transformer design parameters, determine the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the length of the left and right side magnetic powder core magnetic columns, and the electrical isolation distance between the left and right side inner and outer coils; Using a preset transformer magnetic circuit model, according to the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the total number of turns of the primary and secondary winding coils and the transformer design parameters, the magnetic flux of the magnetic flux branch, the total magnetic resistance of the side column magnetic flux branch and the total magnetic resistance of the middle column magnetic flux branch are calculated; Determining the precise middle column air gap length according to the total magnetic resistance of the middle column magnetic flux branch and the geometric parameters of the magnetic core structure; The magnetic core corners of the left and right side columns are calculated by using a preset magnetic core corner model according to the magnetic core structure geometric parameters and the magnetic flux branch magnetic flux; Determine the magnetic resistance of the left and right magnetic powder core columns and the magnetic permeability of the magnetic powder core materials of the left and right magnetic powder core columns based on the magnetic core structure geometric parameters, the lengths of the left and right magnetic powder core columns, the magnetic flux of the magnetic flux branch, and the total magnetic resistance of the side column magnetic flux branch; Determine the primary leakage inductance in the target magnetic core magnetic circuit, the additional leakage inductance in the air near the target winding coil, and the magnetic permeability of the magnetic powder core material of the target left and right magnetic powder core columns according to the total magnetic resistance of the side column magnetic flux branch, the geometric parameters of the magnetic core structure, the total magnetic resistance of the middle column magnetic flux branch, the magnetic flux of the magnetic flux branch, the magnetic resistance of the left and right magnetic powder core columns, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the transformer design parameters, the length of the left and right magnetic powder core columns, the electrical isolation distance between the left and right inner and outer coils, the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns, and the preset design leakage inductance; Based on the preset coil winding method, a magnetic integrated transformer for CLLC converter is designed through the sum of the primary leakage inductance in the target magnetic core magnetic circuit and the additional leakage inductance in the air near the target winding coil, the length of the left and right magnetic powder core magnetic columns, the precise middle column air gap length, and the magnetic permeability of the magnetic powder core material of the target left and right magnetic powder core magnetic columns.

2. The magnetic integrated transformer design method for CLLC converter according to claim 1, characterized in that: The preset constraints are specifically: The product of the number of turns of the primary winding coil allocated to the left side column and the number of turns of the secondary winding coil is equal to the product of the number of turns of the primary winding coil allocated to the right side column and the number of turns of the secondary winding coil.

3. The magnetic integrated transformer design method for CLLC converter according to claim 1, characterized in that: The number of turns of the primary and secondary winding coils allocated to the left and right side columns includes the number of turns of the primary winding coils of the left side column, the number of turns of the secondary winding coils of the left side column, the number of turns of the primary winding coils of the right side column, and the number of turns of the secondary winding coils of the right side column; the lengths of the left and right magnetic powder core magnetic columns include the length of the left magnetic powder core magnetic column and the length of the right magnetic powder core magnetic column; the use of preset constraints to determine the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the lengths of the left and right magnetic powder core magnetic columns, and the electrical isolation distance between the left and right inner and outer coils according to the transformer design parameters, includes: Calculate the number of turns of the primary winding coil of the left side column, the number of turns of the secondary winding coil of the left side column, the number of turns of the primary winding coil of the right side column, and the number of turns of the secondary winding coil of the right side column according to the primary resonant inductance value and the secondary resonant inductance value in the transformer design parameters by using preset constraints; Based on the number of turns of the primary winding coil of the left side column and the number of turns of the secondary winding coil of the left side column, determine the width of the primary winding coil of the left side column and the width of the secondary winding coil of the left side column in the case of tight winding; Comparing the left side column primary winding coil width and the left side column secondary winding coil width in a tightly wound state; The largest left-side column primary winding coil width or the left-side column secondary winding coil width is used as the target left-side column winding coil width, and based on the target left-side column winding coil width, the left-side magnetic powder core magnetic column length is determined; Based on the number of turns of the primary winding coil of the right side column and the number of turns of the secondary winding coil of the right side column, determine the width of the primary winding coil of the right side column and the width of the secondary winding coil of the right side column in the case of tight winding; Comparing the primary winding coil width of the right side column and the secondary winding coil width of the right side column in a tightly wound state; The largest right-side column primary winding coil width or the right-side column secondary winding coil width is used as the target right-side column winding coil width, and based on the target right-side column winding coil width, the right-side magnetic powder core magnetic column length is determined; The electrical isolation distance between the inner and outer coils on the left and right sides is calculated according to the transformer input voltage and the transformer output voltage in the transformer design parameters.

4. The magnetic integrated transformer design method for CLLC converter according to claim 1, characterized in that: The preset transformer magnetic circuit model is used to calculate the magnetic flux of the magnetic flux branch, the total magnetic resistance of the side column magnetic flux branch and the total magnetic resistance of the middle column magnetic flux branch according to the turns of the primary and secondary winding coils allocated to the left and right side columns, the total turns of the primary and secondary winding coils and the transformer design parameters, including: According to the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the primary resonant inductance value, the secondary resonant inductance value, the primary excitation inductance value of the transformer, and the total number of turns of the primary and secondary winding coils, the total magnetic resistance of the side column magnetic flux branch and the total magnetic resistance of the middle column magnetic flux branch are calculated; The preset transformer magnetic circuit model is divided to generate a left side column magnetic flux branch, a right side column magnetic flux branch and a middle column magnetic flux branch; The magnetic flux branch method is used to model the magnetic flux branch of the left side column, the magnetic flux branch of the right side column and the magnetic flux branch of the middle column, and a relationship equation group between the magnetic flux branch of the left side column, the magnetic flux branch of the right side column and the magnetic flux branch of the middle column is generated; The magnetic flux of the magnetic flux branch is calculated by using the relationship equation group between the left side column magnetic flux branch, the right side column magnetic flux branch and the middle column magnetic flux branch according to the total magnetic resistance of the side column magnetic flux branch, the total magnetic resistance of the middle column magnetic flux branch, the total number of turns of the primary and secondary winding coils, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, and the primary winding coil current and the secondary winding coil current in the transformer design parameters; The calculation formula corresponding to the total magnetic resistance of the side column magnetic flux branch and the total magnetic resistance of the middle column magnetic flux branch is specifically: ； Among them, A is the total magnetic resistance parameter of the first side column; B is the total magnetic resistance parameter of the second side column; C is the total magnetic resistance parameter of the third side column; D is the total magnetic resistance parameter of the first middle column; E is the total magnetic resistance parameter of the second middle column; F is the total magnetic resistance parameter of the third middle column; G is the total magnetic resistance parameter of the fourth middle column; H is the total magnetic resistance parameter of the fifth middle column; is the total magnetic resistance of the side column flux branch; is the total magnetic resistance of the center column flux branch; is the primary resonant inductance value; is the secondary side resonant inductance value; The number of turns of the primary winding coil assigned to the left side column; The number of turns of the secondary winding coil allocated to the left side column; is the total number of turns of the secondary winding coil; is the total number of turns of the primary winding coil; The number of turns of the primary winding coil allocated to the right column; The number of turns of the secondary winding coil allocated to the right column; is the primary magnetizing inductance of the transformer.

5. The magnetic integrated transformer design method for CLLC converter according to claim 1, characterized in that: The magnetic flux of the magnetic flux branch includes the magnetic flux of the left side column magnetic flux branch and the magnetic flux of the right side column magnetic flux branch; the preset magnetic core corner model includes the left side column magnetic core corner model and the right side column magnetic core corner model; the magnetic resistance at the left and right side column magnetic core corners includes the magnetic resistance at the left side column magnetic core corner and the magnetic resistance at the right side column magnetic core corner; the preset magnetic core corner model is used to calculate the magnetic resistance at the left and right side column magnetic core corners according to the magnetic core structure geometric parameters and the magnetic flux branch magnetic flux, including: The left-side column magnetic core corner model and the right-side column magnetic core corner model are divided respectively by using the width of the magnetic core side column in the magnetic core structure geometric parameters, and the first magnetic core corner area, the second magnetic core corner area, the third magnetic core corner area and the corner area inside the magnetic core window corresponding to the left-side column magnetic core corner model and the right-side column magnetic core corner model are determined; Using the magnetic flux of the left-side column magnetic flux branch, the width of the core side column in the core structure geometric parameters and the thickness of the core, magnetic resistance calculation is performed on the first core corner area, the second core corner area, the third core corner area and the corner area inside the core window corresponding to the left-side column core corner model to determine the magnetic resistance of the first core corner area, the second core corner area, the third core corner area and the corner area inside the core window corresponding to the left-side column core corner model; The magnetic resistance of the first magnetic core corner area, the magnetic resistance of the second magnetic core corner area, the magnetic resistance of the third magnetic core corner area and the magnetic resistance of the corner area in the core window corresponding to the left side column magnetic core corner model are connected in parallel to determine the magnetic resistance at the left side column magnetic core corner; Using the magnetic flux of the right-side column magnetic flux branch, the width of the core side column in the core structure geometric parameters and the thickness of the core, magnetic resistance calculation is performed on the first core corner area, the second core corner area, the third core corner area and the corner area inside the core window corresponding to the right-side column core corner model to determine the magnetic resistance of the first core corner area, the second core corner area, the third core corner area and the corner area inside the core window corresponding to the right-side column core corner model; The magnetic resistance of the first core corner area, the magnetic resistance of the second core corner area, the magnetic resistance of the third core corner area and the magnetic resistance of the corner area in the core window corresponding to the right side column core corner model are connected in parallel to determine the magnetic resistance at the right side column core corner.

6. The magnetic integrated transformer design method for CLLC converter according to claim 3, characterized in that: The magnetic resistance of the left and right magnetic powder core columns includes the magnetic resistance of the left magnetic powder core column and the magnetic resistance of the right magnetic powder core column; the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns includes the magnetic permeability of the magnetic powder core material of the left magnetic powder core column and the magnetic permeability of the magnetic powder core material of the right magnetic powder core column; the magnetic resistance of the left and right magnetic powder core columns and the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns based on the magnetic core structure geometric parameters, the length of the left and right magnetic powder core columns, the magnetic flux of the magnetic flux branch, and the total magnetic resistance of the side column magnetic flux branch, including: The magnetic resistance of the left residual magnetic core magnetic circuit and the magnetic resistance of the right residual magnetic core magnetic circuit are calculated by using the magnetic column length of the left magnetic powder core, the magnetic column length of the right magnetic powder core, the magnetic flux of the magnetic flux branch, the width of the magnetic core window in the magnetic core structure geometric parameters, the height of the magnetic core window, the width of the magnetic core side column, and the thickness of the magnetic core; Calculate the magnetic resistance of the left magnetic powder core magnetic column according to the magnetic resistance of the left residual magnetic core magnetic circuit and the total magnetic resistance of the side column magnetic flux branch; Calculate the magnetic resistance of the right magnetic powder core magnetic column according to the magnetic resistance of the right residual magnetic core magnetic circuit and the total magnetic resistance of the side column magnetic flux branch; Calculate the magnetic permeability of the magnetic powder core material of the left magnetic powder core column based on the magnetic resistance of the left magnetic powder core column, the length of the left magnetic powder core column, the width of the magnetic core side column in the magnetic core structure geometric parameters, and the thickness of the magnetic core; The magnetic permeability of the magnetic powder core material of the right magnetic powder core column is calculated based on the magnetic resistance of the right magnetic powder core column, the length of the right magnetic powder core column, the width of the core side column in the magnetic core structure geometric parameters, and the thickness of the magnetic core.

7. The magnetic integrated transformer design method for CLLC converter according to claim 6, characterized in that: The method determines the primary leakage inductance in the target magnetic core magnetic circuit, the additional leakage inductance in the air near the target winding coil, and the magnetic permeability of the magnetic powder core material of the target left and right magnetic powder core columns according to the total magnetic resistance of the side column magnetic flux branch, the geometric parameters of the magnetic core structure, the total magnetic resistance of the middle column magnetic flux branch, the magnetic flux of the magnetic flux branch, the magnetic resistance of the left and right magnetic powder core columns, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the transformer design parameters, the length of the left and right magnetic powder core columns, the electrical isolation distance between the left and right inner and outer coils, the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns, and the preset design leakage inductance, including: The additional leakage inductance in the air near the initial winding coil is calculated by using the magnetic resistance of the left and right magnetic powder core columns, the magnetic flux of the magnetic flux branch, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the length of the left and right magnetic powder core columns, the electrical isolation distance between the left and right inner and outer coils, the geometric parameters of the magnetic core structure and the transformer design parameters; Based on the preset designed leakage inductance, determining the primary leakage inductance in the initial magnetic core magnetic circuit; Fine-tune the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns to determine the magnetic permeability of the magnetic powder core material of the middle left and right magnetic powder core columns; The magnetic resistance of the left and right magnetic powder core columns is updated by using the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns, the length of the left and right magnetic powder core columns, the width of the magnetic core side columns in the transformer design parameters, and the thickness of the magnetic core to determine the magnetic resistance of the left and right magnetic powder core columns in the middle; The primary leakage inductance in the initial magnetic core magnetic circuit is updated by using the total magnetic resistance of the side column magnetic flux branch, the magnetic resistance of the left and right magnetic powder core magnetic columns in the middle, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, and the total magnetic resistance of the middle column magnetic flux branch to determine the primary leakage inductance in the middle magnetic core magnetic circuit; The additional leakage inductance in the air near the initial winding coil is updated based on the magnetic resistance of the magnetic powder core columns on the left and right sides of the middle, and the additional leakage inductance in the air near the middle winding coil is determined; Determine whether the sum of the additional leakage inductance in the air near the intermediate winding coil and the primary leakage inductance in the intermediate magnetic core magnetic circuit is equal to the preset design leakage inductance; If so, the additional leakage inductance in the air near the middle winding coil is used as the additional leakage inductance in the air near the target winding coil, the primary leakage inductance in the middle magnetic core magnetic circuit is used as the primary leakage inductance in the target magnetic core magnetic circuit, and the magnetic permeability of the magnetic powder core material of the middle left and right magnetic powder core columns is used as the magnetic permeability of the magnetic powder core material of the target left and right magnetic powder core columns.

8. The magnetic integrated transformer design method for CLLC converter according to claim 7, characterized in that: The method uses the magnetic resistance of the left and right magnetic powder core columns, the magnetic flux of the magnetic flux branch, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the length of the left and right magnetic powder core columns, the electrical isolation distance between the left and right inner and outer coils, the magnetic core structure geometric parameters and the transformer design parameters to calculate the additional leakage inductance in the air near the initial winding coil, including: Calculate the magnetic voltage drop at both ends of the left and right magnetic powder core columns by using the magnetic resistance of the left and right magnetic powder core columns and the magnetic flux of the magnetic flux branch; According to the magnetic voltage drop at both ends of the left and right magnetic powder core magnetic columns, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the length of the left and right magnetic powder core magnetic columns, the electrical isolation distance between the left and right inner and outer coils, and the transformer design parameters, calculate the magnetic field strength in the primary winding coils of the left and right side columns, the magnetic field strength in the electrical isolation layer of the left and right side columns, and the magnetic field strength in the secondary winding coils of the left and right side columns; The total air leakage inductance energy of the left and right side column winding coils is calculated by using the magnetic field strength in the primary winding coils of the left and right side columns, the magnetic field strength in the electrical isolation layer of the left and right side columns, the magnetic field strength in the secondary winding coils of the left and right side columns, and the geometric parameters of the magnetic core structure; Based on the total air leakage inductance energy of the left and right side column winding coils and the transformer design parameters, determine the primary leakage inductance on the left side column and the primary leakage inductance on the right side column; The primary leakage inductance on the left side column and the primary leakage inductance on the right side column are added to determine the additional leakage inductance in the air near the initial winding coil.

9. The magnetic integrated transformer design method for CLLC converter according to claim 1, characterized in that: The precise center column air gap length is specifically: ； in, is the precise center column air gap length; is the total magnetic resistance of the middle column magnetic flux branch; a is the first accurate middle column air gap length parameter; b is the second accurate middle column air gap length parameter; c is the third accurate middle column air gap length parameter; d is the fourth accurate middle column air gap length parameter; is the height of the core window; is the width of the core column; is the thickness of the magnetic core; is the magnetic permeability of the core material of the EE type core used; is the magnetic permeability of air.

10. A magnetic integrated transformer design device for CLLC converter, characterized in that: include: An acquisition module is used to acquire transformer design parameters, and determine the total number of turns of the primary and secondary winding coils, the core model, and the core structure geometric parameters corresponding to the core model according to the transformer design parameters by using a preset area product method; The first calculation module is used to determine the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the length of the left and right side magnetic powder core magnetic columns, and the electrical isolation distance between the left and right side inner and outer layer coils according to the transformer design parameters by using preset constraints; The second calculation module is used to calculate the magnetic flux of the magnetic flux branch, the total magnetic resistance of the side column magnetic flux branch and the total magnetic resistance of the middle column magnetic flux branch according to the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the total number of turns of the primary and secondary winding coils and the transformer design parameters by using a preset transformer magnetic circuit model; A third calculation module is used to determine the precise middle column air gap length according to the total magnetic resistance of the middle column magnetic flux branch and the geometric parameters of the magnetic core structure; A fourth calculation module is used to calculate the magnetic resistance at the corners of the left and right side column magnetic cores according to the geometric parameters of the magnetic core structure and the magnetic flux of the magnetic flux branch by using a preset magnetic core corner model; A fifth calculation module is used to determine the magnetic resistance of the left and right magnetic powder core columns and the magnetic permeability of the magnetic powder core materials of the left and right magnetic powder core columns based on the magnetic core structure geometric parameters, the lengths of the left and right magnetic powder core columns, the magnetic flux of the magnetic flux branch, and the total magnetic resistance of the side column magnetic flux branch; The target parameter output module is used to determine the primary leakage inductance in the target magnetic core magnetic circuit, the additional leakage inductance in the air near the target winding coil, and the magnetic permeability of the magnetic powder core material of the target left and right magnetic powder core columns according to the total magnetic resistance of the side column magnetic flux branch, the geometric parameters of the magnetic core structure, the total magnetic resistance of the middle column magnetic flux branch, the magnetic flux of the magnetic flux branch, the magnetic resistance of the left and right magnetic powder core columns, the number of turns of the primary and secondary winding coils allocated to the left and right side columns, the transformer design parameters, the length of the left and right magnetic powder core columns, the electrical isolation distance between the left and right inner and outer coils, the magnetic permeability of the magnetic powder core material of the left and right magnetic powder core columns, and the preset design leakage inductance; The design module is used to design a magnetic integrated transformer for a CLLC converter based on a preset coil winding method, through the sum of the primary leakage inductance in the target core magnetic circuit and the additional leakage inductance in the air near the target winding coil, the length of the left and right magnetic powder core magnetic columns, the precise middle column air gap length, and the magnetic permeability of the magnetic powder core material of the target left and right magnetic powder core magnetic columns.

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