Design method of transformer winding, PCB transformer and power supply module

Abstract

The invention provides a design method of a transformer winding, a PCB transformer and a power module, and the design method comprises the steps: determining an excitation coefficient set of the transformer winding based on the turn ratio of the transformer winding; all excitation coefficients in the excitation coefficient set are fully arranged, a plurality of non-repeated arrangement sequences are obtained, and a coefficient matrix is formed; performing stage summation operation on the coefficient matrix to obtain a stage summation matrix; and obtaining a first matrix and / or a second matrix based on the stage summation matrix, and obtaining the optimal stacking mode of the transformer winding. By means of the design method of the transformer winding, the PCB transformer and the power module, the problem that a traditional sandwich type winding stacking mode is prone to causing high transformer loss is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and in particular to a design method for a transformer winding, a PCB transformer and a power module. Background Art

[0002] In high power density power modules, PCB transformers are core components, and their performance directly affects the efficiency and thermal stability of the power modules. The losses of PCB transformers are mainly composed of hysteresis loss, eddy current loss and residual loss of the transformer, as well as AC loss and DC loss of the windings, which are closely related to the magnetization process of the transformer material.

[0003] In high-frequency applications, transformer loss is particularly prominent because high-frequency magnetic fields can cause large hysteresis loops and eddy currents to form inside transformer materials, thereby increasing losses. In the prior art, a sandwich winding stacking structure (alternating stacking of primary windings and secondary windings) is usually used to reduce transformer losses. However, this winding stacking method has the following defects.

[0004] First, there is a lack of systematic design methods. The design of traditional sandwich winding stacking structures mainly relies on experience and simulation feedback, resulting in low design efficiency and difficulty in achieving optimal performance.

[0005] Second, the magnetic field is unevenly distributed. The layout of the traditional sandwich-type winding stacking structure can easily cause uneven distribution of the transformer's magnetic field strength. The magnetic induction intensity in some local areas is too high, which aggravates the transformer's losses.

[0006] Third, the thermal coupling problem is prominent. The heat generated by transformer loss and winding loss is coupled with each other, resulting in increased temperature rise, further increasing total loss and reducing the reliability of the power module.

[0007] Fourth, the high-frequency adaptability is poor. As the operating frequency increases (for example, 200KHz to 1MHz), the traditional sandwich winding stacking structure has significant skin effect and proximity effect, uneven winding current distribution, and exponential growth in transformer loss, which makes it difficult to meet the needs of high-frequency power modules.

[0008] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present invention and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because these solutions are described in the background technology section of the present invention. Summary of the invention

[0009] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a transformer winding design method, a PCB transformer and a power module, which are used to solve the problem that the traditional sandwich winding stacking method easily leads to high transformer loss.

[0010] To achieve the above-mentioned object and other related objects, the present invention provides a transformer winding design method, the design method comprising:

[0011] Determining a set of excitation coefficients of the transformer windings based on the turns ratio of the transformer windings;

[0012] Performing full permutation on each excitation coefficient in the excitation coefficient set to obtain a plurality of non-repeated permutation series and form a coefficient matrix;

[0013] Performing a stage summation operation on the coefficient matrix to obtain a stage summation matrix;

[0014] The first matrix and / or the second matrix are obtained based on the stage summation matrix, and thereby the optimal stacking mode of the transformer winding is obtained.

[0015] Optionally, the method for determining the excitation coefficient set includes: based on the turns ratio of the transformer winding, obtaining the excitation coefficient of the primary single-turn winding and the excitation coefficient of the secondary single-turn winding in the transformer winding, and constructing the excitation coefficient set accordingly.

[0016] Optionally, the excitation coefficient of the primary single-turn winding and the excitation coefficient of the secondary single-turn winding satisfy , the excitation coefficient set satisfies , where p i is the excitation coefficient of the primary winding turn i, s j is the excitation coefficient of the jth turn of the secondary winding, n p is the number of turns of the primary winding, n s is the number of turns of the secondary winding, P is the excitation coefficient set, p 1 ~p np is the excitation coefficient corresponding to each primary winding, s 1 ~s ns is the excitation coefficient corresponding to each secondary winding.

[0017] Optionally, for the excitation coefficient set (n p +n s ) excitation coefficients are fully arranged to obtain There are a number of non-repeating permutations, and the coefficient matrix satisfies ,in, is the coefficient matrix, For each permutation series, n p is the number of turns of the primary winding, n s is the number of turns of the secondary winding.

[0018] Optionally, the method of obtaining the stage summation matrix includes: Designing an upper triangular matrix based on the coefficient matrix, and performing a stage summation operation on the coefficient matrix based on the upper triangular matrix to obtain a primary stage matrix; The last column in the primary stage matrix is ​​removed to obtain the stage sum matrix.

[0019] Optionally, the upper triangular matrix satisfies , the matrix in the primary stage satisfies ,in, is the primary stage matrix, is the coefficient matrix, is an upper triangular matrix.

[0020] Optionally, the method for obtaining the first matrix includes: obtaining the maximum absolute value of the elements in each row of the stage sum matrix, and using this to form the first matrix; wherein the first matrix satisfies , is the first matrix, The maximum absolute value of the elements in each row of the sum matrix is ​​obtained in stages. is the kth column of each row in the stage summation matrix, n p is the number of turns of the primary winding, n s is the number of turns of the secondary winding.

[0021] Optionally, the method for obtaining the second matrix includes: obtaining the sum of the absolute values ​​of the elements in each row of the stage summation matrix, and using this to form the second matrix; wherein the second matrix satisfies , is the second matrix, The sum of the absolute values ​​of the elements in each row of the stage sum matrix, is the kth column of each row in the stage summation matrix, n p is the number of turns of the primary winding, n s is the number of turns of the secondary winding.

[0022] Optionally, the method for obtaining the optimal stacking method of the transformer winding includes: taking the number of rows corresponding to the minimum value of the elements in the first matrix and / or the second matrix as the target number of rows, selecting the permutation sequence located at the target number of rows from the coefficient matrix, and taking the corresponding stacking method as the optimal stacking method.

[0023] The present invention also provides a PCB transformer, which includes a transformer winding, wherein the primary winding and the secondary winding in the transformer winding are arranged in an optimal stacking manner obtained by the design method described in any one of the above items.

[0024] The present invention also provides a power module, which includes the PCB transformer described above.

[0025] As described above, the transformer winding design method, PCB transformer and power module of the present invention, through full permutation matrix operation and mathematical modeling, propose a general design method for the optimal winding stacking method, which not only solves the blindness and inefficiency of the traditional design relying on experience and simulation feedback, but also can effectively reduce the transformer loss and minimize the transformer loss; the winding arranged based on the optimal stacking method has a balanced magnetic field distribution, and the balanced magnetic field distribution and extremely low loss can reduce local hot spots, reduce the thermal coupling effect between the transformer and the winding, and significantly improve the thermal stability and reliability of the power module. The design method of the present invention is applicable to various PCB transformers (especially multi-winding complex structures with arbitrary turns ratios), has high design flexibility, and can be extended to new energy, electric vehicles and other fields; the design method of the present invention can achieve performance improvement only by optimizing the winding stacking method, without the need for additional materials or process improvements, and the cost increase is almost zero, which has extremely high cost-effectiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Shown is a flow chart of a design method in an embodiment of the present invention.

[0027] Figure 2 A schematic diagram showing the stacking method corresponding to the arrangement of the columns in the first row of the coefficient matrix of a transformer winding having a turns ratio of 3:2.

[0028] Figure 3 A schematic diagram showing the stacking method corresponding to the arrangement of the columns in the second row of the coefficient matrix of a transformer winding having a turns ratio of 3:2.

[0029] Figure 4 A schematic diagram showing the stacking method corresponding to the arrangement of the columns in the third row in the coefficient matrix of a transformer winding having a turns ratio of 3:2.

[0030] Figure 5 A schematic diagram showing the stacking method corresponding to the arrangement of the columns in the 4th row in the coefficient matrix of the transformer winding having a turns ratio of 3:2.

[0031] Figure 6 The figure shows the stacking method corresponding to the arrangement of the columns in the 5th row of the coefficient matrix of the transformer winding with a turns ratio of 3:2.

[0032] Figure 7 Shown by Figures 2 to 6 Schematic diagram of transformer losses consisting of the transformer windings shown.

[0033] Figure 8 Shown by Figures 2 to 6Schematic diagram of the change curve of the magnetic field strength and leakage inductance of the transformer composed of the transformer windings shown. DETAILED DESCRIPTION

[0034] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0035] See also Figures 1 to 8 It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the form, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0036] like Figure 1 As shown, this embodiment provides a transformer winding design method, including the following steps, for example, step S1 to step S4.

[0037] Step S1, determining an excitation coefficient set of a transformer winding based on a turns ratio of the transformer winding.

[0038] In one embodiment, a method for determining an excitation coefficient set includes: based on the turns ratio of the transformer winding, obtaining the excitation coefficient of the primary single-turn winding and the excitation coefficient of the secondary single-turn winding in the transformer winding, and constructing an excitation coefficient set based on this; wherein the excitation coefficient set includes the excitation coefficient corresponding to each primary winding and the excitation coefficient corresponding to each secondary winding, a total of Excitation coefficient, n p is the number of turns of the primary winding, n s is the number of turns of the secondary winding. It should be noted that the turns ratio of the transformer winding is one of the design specifications of the PCB transformer, which is determined by the actual application scenario and is a known parameter.

[0039] In one example, the excitation coefficient of the primary single-turn winding satisfies ,and, , where p i is the excitation coefficient of the primary winding turn i, n s is the number of turns of the secondary winding; the excitation coefficient of the secondary single-turn winding satisfies ,and, , where s j is the excitation coefficient of the jth turn of the secondary winding, n pis the number of turns of the primary winding; the excitation coefficient set satisfies , where P is the excitation coefficient set, p 1 ~p np is the excitation coefficient corresponding to each primary winding, s 1 ~s ns is the excitation coefficient corresponding to each secondary winding.

[0040] Take the transformer winding turns ratio of 3:2 as an example, that is, n p =3, n s =2, at this time, the values ​​of i are 1, 2 and 3 respectively, and the values ​​of j are 1 and 2 respectively, then, p 1 =p 2 =p 3 =2,s 1 =s 2 = -3, P = {p 1 , p 2 , p 3 ,s 1 ,s 2}.

[0041] Step S2, performing full permutation of each excitation coefficient in the excitation coefficient set, obtaining a number of non-repeating permutation series and forming a coefficient matrix to represent all possible arrangement combinations of the transformer windings.

[0042] In this step, the excitation coefficient set The excitation coefficients are fully arranged to obtain There are a number of non-repeating permutations, where n p is the number of turns of the primary winding, n s is the number of turns of the secondary winding. In one example, the coefficient matrix satisfies ,in, is a coefficient matrix, and the coefficient matrix includes OK List, are the permutation sequences, and T is the transpose of the matrix.

[0043] The excitation coefficient set P = {p 1 , p 2 , p 3 ,s 1 ,s 2} as an example, the five excitation coefficients are fully arranged to obtain ten non-repeating arrangement series, among which the ten non-repeating arrangement series are (2 2 2 -3 -3), (2 2 -3 2 -3), (2 2 -3 -3 2), (2 -3 2 2 -3), (2 -3 2 -3 2), (2 -3 -3 2 2), (-3 2 2 2 -3), (-3 2 2-3 2), (-3 2 -3 2 2) and (-3 -3 2 2 2); at this time, the coefficient matrix .

[0044] Step S3, performing a stage summation operation on the coefficient matrix to obtain a stage summation matrix. In one embodiment, the method for obtaining the stage summation matrix includes the following steps, for example, step S31 and step S32.

[0045] Step S31, designing an upper triangular matrix based on the coefficient matrix, and performing a stage summation operation on the coefficient matrix based on the upper triangular matrix to obtain a primary stage matrix.

[0046] In one example, when designing an upper triangular matrix based on a coefficient matrix, the number of rows and columns of the upper triangular matrix are equal to the number of columns of the coefficient matrix; wherein the upper triangular matrix satisfies , is an upper triangular matrix, and the upper triangular matrix includes OK List.

[0047] The stage summation operation of the coefficient matrix is ​​completed by multiplying the coefficient matrix by the upper triangular matrix to obtain the primary stage matrix; wherein the primary stage matrix satisfies , is the primary stage matrix, and the primary stage matrix includes OK List.

[0048] With coefficient matrix For example, the upper triangular matrix , at this time, the primary stage matrix .

[0049] Step S32, remove the last column in the primary stage matrix to obtain the stage sum matrix.

[0050] Primary stage matrix For example, the stage summation matrix .

[0051] Step S4, obtaining a first matrix and / or a second matrix based on the stage sum matrix, and using this to obtain an optimal stacking method of the transformer winding.

[0052] In different application scenarios, the turns ratio of the transformer winding is designed differently, that is, the turns of the primary winding and the turns of the secondary winding are designed differently. For example, the turns of the primary winding can be designed to be unequal to the turns of the secondary winding, that is, Of course, the number of turns of the primary winding can also be designed to be equal to the number of turns of the secondary winding, that is, ; However, no matter the number of turns of the primary winding is not equal to the number of turns of the secondary winding, or the number of turns of the primary winding is equal to the number of turns of the secondary winding, at least one of the first matrix and the second matrix can be obtained based on the stage summation matrix, and the optimal stacking method of the transformer winding can be obtained by this. It should be noted that when the number of turns of the primary winding is equal to the number of turns of the secondary winding, it usually refers to ,because The corresponding stacking method of the transformer winding is fixed, and there is no so-called optimal stacking method.

[0053] In one embodiment, when obtaining the first matrix based on the stage sum matrix, the specific method includes: obtaining the maximum absolute value of the elements in each row of the stage sum matrix, and forming the first matrix therefrom; wherein the first matrix satisfies , is the first matrix, The maximum absolute value of the elements in each row of the sum matrix is ​​obtained in stages. is the kth column of each row in the stage summation matrix, n p is the number of turns of the primary winding, n s is the number of turns of the secondary winding.

[0054] Summation matrix in stages For example, the first matrix .

[0055] When obtaining the second matrix based on the stage sum matrix, the specific method includes: obtaining the sum of the absolute values ​​of the elements in each row of the stage sum matrix, and using this to form the second matrix; wherein the second matrix satisfies , is the second matrix, The sum of the absolute values ​​of the elements in each row of the stage sum matrix, is the kth column of each row in the stage summation matrix, n p is the number of turns of the primary winding, n s is the number of turns of the secondary winding.

[0056] Summation matrix in stages For example, the second matrix .

[0057] In one embodiment, when obtaining the optimal stacking method of the transformer winding based on the first matrix and / or the second matrix, the specific method includes: taking the number of rows corresponding to the minimum value of the elements in the first matrix and / or the second matrix as the target number of rows, selecting the arrangement series located at the target number of rows from the coefficient matrix, and taking the corresponding stacking method as the optimal stacking method.

[0058] When obtaining the optimal stacking method of the transformer winding based on the first matrix, the first matrix For example, the value of the 5th row element is the smallest, so the 5th row is taken as the target row number; the permutation sequence (2-3 2 -3 2) located in the 5th row is selected from the coefficient matrix, and the corresponding stacking method is used as the optimal stacking method to guide the design of the transformer winding. Among them, the stacking methods of the corresponding transformer windings are from bottom to top: primary winding-secondary winding-primary winding-secondary winding-primary winding.

[0059] When obtaining the optimal stacking method of the transformer winding based on the second matrix, the second matrix For example, the value of the 5th row element is the smallest, so the 5th row is taken as the target row number; the permutation sequence (2-3 2 -3 2) located in the 5th row is selected from the coefficient matrix, and the corresponding stacking method is used as the optimal stacking method to guide the design of the transformer winding. Among them, the stacking methods of the corresponding transformer windings are from bottom to top: primary winding-secondary winding-primary winding-secondary winding-primary winding.

[0060] When the optimal stacking method of the transformer winding is obtained based on the first matrix and the second matrix, the 5th row is also taken as the target row number, and the arrangement sequence (2 -3 2 -3 2) located in the 5th row is selected from the coefficient matrix, and the corresponding stacking method is taken as the optimal stacking method to guide the design of the transformer winding.

[0061] It can be seen that no matter whether the optimal stacking method of the transformer winding is obtained based on the first matrix, or the optimal stacking method of the transformer winding is obtained based on the second matrix, or even the optimal stacking method of the transformer winding is obtained based on the first matrix and the second matrix, the result is the same. In practical applications, since it is simpler and more convenient to obtain the first matrix, the first matrix is ​​usually obtained based on the stage summation matrix, and the optimal stacking method of the transformer winding is obtained based on the first matrix. In addition, in the case where the number of turns of the primary winding is equal to the number of turns of the secondary winding, the optimal stacking method obtained may not be unique. At this time, any optimal stacking method can be selected to guide the design based on the actual situation.

[0062] Accordingly, the present embodiment further provides a PCB transformer, including a transformer winding, wherein the primary winding and the secondary winding in the transformer winding are arranged according to the optimal stacking method obtained by the above design method; of course, the PCB transformer may also include other structures, such as a magnetic core, etc., and no excessive restrictions are imposed on this. The PCB transformer in the present embodiment can minimize transformer losses through the above winding stacking design.

[0063] With coefficient matrix For example, combined with the above, we can know that the stacking method corresponding to the arrangement sequence (2 -3 2 -3 2) in the 5th row is the optimal stacking method. The stacking methods corresponding to the 1st to 5th rows guide the design respectively as follows Figures 2 to 6 The transformer windings shown in FIG. 1 are used to perform simulation tests on the transformers formed by the transformer windings. The simulation test results are shown in FIG. Figure 7 and Figure 8 shown by Figure 7 and Figure 8 It can be seen that the transformer with the optimal stacking method has the lowest loss, the lowest magnetic field strength, and the smallest leakage inductance.

[0064] Accordingly, this embodiment further provides a power module, including a PCB transformer, wherein the PCB transformer is implemented using the transformer structure described above; of course, the power module may also include other structures, such as a filter, a controller, etc., and no further restrictions are imposed on this. In one implementation, the power module of this embodiment is a high power density power module.

[0065] In summary, the design method of a transformer winding, a PCB transformer and a power module of the present invention, through full permutation matrix operation and mathematical modeling, propose a general design method for the optimal winding stacking method, which not only solves the blindness and inefficiency of the traditional design relying on experience and simulation feedback, but also can effectively reduce the transformer loss and minimize the transformer loss; the winding arranged based on the optimal stacking method has a balanced magnetic field distribution, and the balanced magnetic field distribution and extremely low loss can reduce local hot spots, reduce the thermal coupling effect between the transformer and the winding, and significantly improve the thermal stability and reliability of the power module. The design method of the present invention is suitable for various PCB transformers (especially multi-winding complex structures with arbitrary turns ratios), has high design flexibility, and can be extended to new energy, electric vehicles and other fields; the design method of the present invention can achieve performance improvement only by optimizing the winding stacking method, without the need for additional materials or process improvements, and the cost is almost zero, which has extremely high cost-effectiveness. Therefore, the present invention effectively overcomes the various shortcomings in the prior art and has a high industrial utilization value.

[0066] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A design method for transformer windings, characterized in that: The design method comprises: Determining a set of excitation coefficients of the transformer windings based on the turns ratio of the transformer windings; Performing full permutation on each excitation coefficient in the excitation coefficient set to obtain a plurality of non-repeated permutation series and form a coefficient matrix; Performing a stage summation operation on the coefficient matrix to obtain a stage summation matrix; The first matrix and / or the second matrix are obtained based on the stage summation matrix, and thereby the optimal stacking mode of the transformer winding is obtained.

2. The transformer winding design method according to claim 1, characterized in that: The method for determining an excitation coefficient set includes: obtaining the excitation coefficient of a primary single-turn winding and an excitation coefficient of a secondary single-turn winding in the transformer winding based on the turns ratio of the transformer winding, and constructing the excitation coefficient set based on the excitation coefficient.

3. The transformer winding design method according to claim 2, characterized in that: The excitation coefficient of the primary single-turn winding and the excitation coefficient of the secondary single-turn winding satisfy , the excitation coefficient set satisfies , where p i is the excitation coefficient of the primary winding turn i, s j is the excitation coefficient of the jth turn of the secondary winding, n p is the number of turns of the primary winding, n s is the number of turns of the secondary winding, P is the set of excitation coefficients, p1~p np is the excitation coefficient corresponding to each primary winding, s1~s ns is the excitation coefficient corresponding to each secondary winding.

4. The transformer winding design method according to claim 1, characterized in that: For the excitation coefficient set (n p +n s ) excitation coefficients are fully arranged to obtain There are a number of non-repeating permutations, and the coefficient matrix satisfies ,in, is the coefficient matrix, For each permutation series, n p is the number of turns of the primary winding, n s is the number of turns of the secondary winding.

5. The transformer winding design method according to claim 1, characterized in that: Methods for obtaining the stage summation matrix include: Designing an upper triangular matrix based on the coefficient matrix, and performing a stage summation operation on the coefficient matrix based on the upper triangular matrix to obtain a primary stage matrix; The last column in the primary stage matrix is ​​removed to obtain the stage sum matrix.

6. The transformer winding design method according to claim 5, characterized in that: The upper triangular matrix satisfies , the matrix in the primary stage satisfies ,in, is the primary stage matrix, is the coefficient matrix, is an upper triangular matrix.

7. The transformer winding design method according to claim 1, characterized in that: The method for obtaining the first matrix includes: obtaining the maximum absolute value of the elements in each row of the stage summation matrix, and using this to form the first matrix; wherein the first matrix satisfies , is the first matrix, The maximum absolute value of the elements in each row of the stage sum matrix, is the kth column of each row in the stage sum matrix, n p is the number of turns of the primary winding, n s is the number of turns of the secondary winding.

8. The transformer winding design method according to claim 1, characterized in that: The method for obtaining the second matrix includes: obtaining the sum of the absolute values ​​of the elements in each row of the stage summation matrix, and using this to form the second matrix; wherein the second matrix satisfies , is the second matrix, The sum of the absolute values ​​of the elements in each row of the stage sum matrix, is the kth column of each row in the stage sum matrix, n p is the number of turns of the primary winding, n s is the number of turns of the secondary winding.

9. The transformer winding design method according to claim 1, characterized in that: The method for obtaining the optimal stacking method of the transformer winding includes: taking the number of rows corresponding to the minimum value of the elements in the first matrix and / or the second matrix as the target number of rows, selecting the arrangement series located at the target number of rows from the coefficient matrix, and taking the corresponding stacking method as the optimal stacking method.

10. A PCB transformer, characterized in that: The PCB transformer includes a transformer winding, wherein the primary winding and the secondary winding in the transformer winding are arranged in an optimal stacking manner obtained according to the design method according to any one of claims 1 to 9.

11. A power module, characterized in that: The power module comprises the PCB transformer as claimed in claim 10.

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