A design method and related device for a medium- and high-frequency transformer in a dual active bridge converter

Abstract

The present invention discloses a method and related device for designing a high-frequency transformer in a dual-active bridge converter, including: combining the high-frequency transformer design theory based on the dual-active bridge operation principle, deriving the loss formula of the transformer under three-phase shift modulation; based on the three-phase shift modulation, obtaining the relationship between the maximum magnetic density and the phase shift angle of the high-frequency transformer, thereby determining the magnetic density constraint condition; according to the effective value of the high-frequency transformer current and combined with the three-phase shift modulation, obtaining the window area constraint; according to the loss formula, the magnetic density constraint condition and the window area constraint, determining the optimization design target and constraint condition of the high-frequency transformer under the three-phase shift modulation, and using the NSGA-II algorithm to design the high-frequency transformer parameters. This solves the problem that the prior art cannot be combined with the DAB operation principle when designing a high-frequency transformer, resulting in inaccurate calculation of the transformer loss under specific working conditions during design, resulting in inaccurate optimization design results.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and in particular to a design method for a high frequency transformer in a dual active bridge converter and a related device. Background Art

[0002] With the rapid development of power electronics technology, DC transformers are increasingly used in scenarios such as new energy collection and distribution. The dual active bridge (DAB) converter has become one of the most suitable topologies for DC transformers due to its high power density, bidirectional energy transmission and fast adjustment speed. As the core component of the DAB converter, the high-frequency transformer is significantly different from the traditional power frequency transformer in design and function.

[0003] In the past, in the design of high-frequency transformers, the AP method is often used to preliminarily select magnetic components, and then the efficiency, power density, etc. are used as design targets, and the genetic algorithm, traversal method, etc. are used to solve the multi-objective optimization problem to obtain the optimal design solution or the optimal design solution set. However, for the high-frequency transformer used in the dual active bridge converter, the voltage at both ends and the transmitted power are closely related to the operation mode of the converter. When the converter adopts three-phase shift modulation (TPS modulation), different phase shift angle combinations can be used to achieve the same power transmission of the converter, thereby achieving the goals of reducing current stress, reducing return power, and soft switching. However, different phase shift angles will produce different voltage waveforms at both ends of the high-frequency transformer. However, the traditional design method fails to consider the specific waveforms at both ends of the transformer when it is working, resulting in inaccurate calculation of saturation flux density and transformer window area during design, which may cause saturation problems when the transformer is running. In the process of transformer manufacturing, the winding is difficult to wind due to the error in calculating the window area. Furthermore, the existing technology cannot be combined with the DAB operation principle when designing high-frequency transformers, resulting in inaccurate calculation of transformer losses under specific working conditions during design, making the optimization design results inaccurate. Summary of the invention

[0004] The present invention provides a method and related device for designing a high-frequency transformer in a dual active bridge converter, which is used to solve the problem that the prior art cannot combine the high-frequency transformer with the DAB operating principle when designing the high-frequency transformer, resulting in inaccurate calculation of the transformer loss under specific working conditions during design, leading to inaccurate optimization design results.

[0005] In view of this, a first aspect of the present invention provides a method for designing a high frequency transformer in a dual active bridge converter, the method comprising:

[0006] Combining the high-frequency transformer design theory with the dual active bridge operation principle, the transformer loss formula under three-phase shift modulation is derived;

[0007] Obtain the relationship between the maximum magnetic flux density and the phase shift angle of the high-frequency transformer, so as to determine the magnetic flux density constraint conditions;

[0008] According to the effective value of high frequency transformer current and combined with three-phase shift modulation, the window area constraint is obtained;

[0009] The optimization design objectives and constraints of the high-frequency transformer under three-phase shift modulation are determined according to the loss formula, the magnetic density constraint conditions and the window area constraint, and the NSGA-II algorithm is used to design the parameters of the high-frequency transformer.

[0010] Optionally, the high-frequency transformer design theory combined with the dual active bridge operation principle is used to derive the transformer loss formula under three-phase shift modulation, including:

[0011] Based on the loss of the unit core of the high-frequency transformer under non-sinusoidal excitation, it is deduced that when three-phase shift modulation is used, the core loss of the high-frequency transformer and the phase shift angle D in the right bridge arm are 3 relationship;

[0012] The high-frequency transformer winding loss is derived based on the winding AC resistance and effective value of the inductor current of the high-frequency transformer;

[0013] The conduction loss is taken as the loss of the switching devices of the dual active bridge converter in three-phase shift modulation;

[0014] According to the high-frequency transformer core loss and the phase shift angle D in the right bridge arm 3 The total loss is obtained by calculating the relationship between the high-frequency transformer winding loss and the switching device loss;

[0015] Among them, the optimization expression of the total loss is:

[0016] ;

[0017] In the formula, is the volume of the core, For the indivual The conduction loss, that is, the loss of the switching device, is the core loss of the high-frequency transformer and the phase shift angle in the right bridge arm relationship, is the high frequency transformer winding loss.

[0018] Optionally, the expression of the magnetic density constraint condition is:

[0019] ;

[0020] In the formula, is the saturation flux density of the core material, is the design margin, is the phase shift angle in the right bridge arm, is the period of excitation applied across the high-frequency transformer, is the output voltage of the dual active bridge converter, is the number of turns of the secondary winding, is the effective area of ​​the core.

[0021] Optionally, the expression of the window area constraint is:

[0022] ;

[0023] In the formula, is the number of turns of the primary winding, is the period of excitation applied across the high-frequency transformer, is the series inductor, , are the primary and secondary voltages of the transformer, is the inner phase angle of the left bridge arm, is the outward shift phase angle between the bridge arms, is the phase shift angle in the right bridge arm, For a certain moment, is the current density, is the window coefficient, A w is the window area, T r is a function of time t.

[0024] Optionally, the expression of the optimization design objective and constraint condition is:

[0025] ;

[0026] In the formula, is the volume of the core, For the indivual The conduction loss, that is, the loss of the switching device, is the core loss of the high-frequency transformer and the phase shift angle in the right bridge arm relationship, is the high frequency transformer winding loss; is the saturation flux density of the core material, is the design margin, is the phase shift angle in the right bridge arm, is the period of excitation applied across the high-frequency transformer, is the output voltage of the dual active bridge converter, is the number of turns of the secondary winding, is the effective area of ​​the core; is the number of turns of the primary winding, is the current density, is the window coefficient, , They are respectively the effective values ​​of the primary and secondary sides of the high-frequency transformer; is the rated power of the high frequency transformer, is the volume of the high-frequency transformer core, is the volume of high frequency transformer winding.

[0027] A second aspect of the present invention provides a high frequency transformer design system for a dual active bridge converter, the system comprising:

[0028] The first analysis unit is used to combine the high-frequency transformer design theory with the dual active bridge operation principle to derive the transformer loss formula under three-phase shift modulation;

[0029] The second analysis unit is used to obtain the relationship between the maximum magnetic flux density and the phase shift angle of the high-frequency transformer, so as to determine the magnetic flux density constraint condition;

[0030] A third analysis unit is used to obtain a window area constraint according to the effective value of the high-frequency transformer current and in combination with three-phase shift modulation;

[0031] The design unit is used to determine the optimization design objectives and constraints of the high-frequency transformer under three-phase shift modulation according to the loss formula, the magnetic density constraint condition and the window area constraint, and to design the parameters of the high-frequency transformer using the NSGA-II algorithm.

[0032] Optionally, the first analysis unit is specifically used to:

[0033] Based on the loss of the unit core of the high-frequency transformer under non-sinusoidal excitation, it is deduced that when three-phase shift modulation is used, the core loss of the high-frequency transformer and the phase shift angle D in the right bridge arm are 3 relationship;

[0034] The high-frequency transformer winding loss is derived based on the winding AC resistance and effective value of the inductor current of the high-frequency transformer;

[0035] The conduction loss is taken as the loss of the switching devices of the dual active bridge converter in three-phase shift modulation;

[0036] According to the high-frequency transformer core loss and the phase shift angle D in the right bridge arm 3 The total loss is obtained by calculating the relationship between the high-frequency transformer winding loss and the switching device loss;

[0037] Among them, the optimization expression of the total loss is:

[0038] ;

[0039] In the formula, is the volume of the core, For the indivual The conduction loss, that is, the loss of the switching device, is the core loss of the high-frequency transformer and the phase shift angle in the right bridge arm relationship, is the high frequency transformer winding loss.

[0040] Optionally, the expression of the optimization design objective and constraint condition is:

[0041] ;

[0042] In the formula, is the volume of the core, For the indivual The conduction loss, that is, the loss of the switching device, is the core loss of the high-frequency transformer and the phase shift angle in the right bridge arm relationship, is the high frequency transformer winding loss; is the saturation flux density of the core material, is the design margin, is the phase shift angle in the right bridge arm, is the period of excitation applied across the high-frequency transformer, is the output voltage of the dual active bridge converter, is the number of turns of the secondary winding, is the effective area of ​​the core; is the number of turns of the primary winding, is the current density, is the window coefficient, , They are respectively the effective values ​​of the primary and secondary sides of the high-frequency transformer; is the rated power of the high frequency transformer, is the volume of the high-frequency transformer core, is the volume of high frequency transformer winding.

[0043] A third aspect of the present invention provides a high frequency transformer design device for a dual active bridge converter, the device comprising a processor and a memory:

[0044] The memory is used to store program code and transmit the program code to the processor;

[0045] The processor is used to execute the steps of the method for designing a high-frequency transformer in a dual active bridge converter as described in the first aspect according to the instructions in the program code.

[0046] A fourth aspect of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium is used to store program code, and the program code is used to execute the method for designing a high-frequency transformer in a dual active bridge converter described in the first aspect.

[0047] It can be seen from the above technical solutions that the present invention has the following advantages:

[0048] 1. The optimization design of high-frequency transformers in traditional dual active bridge converters ignores the operating principle of DAB converters, resulting in inaccurate calculation of high-frequency transformer losses and inaccurate optimization design results. The present invention combines TPS modulation, analyzes the relationship between the waveform and the phase shift angle at both ends of the high-frequency transformer under TPS modulation, derives the relationship between the core loss of the high-frequency transformer and the phase shift angle, obtains the core loss expression under actual working conditions, improves the accuracy of high-frequency transformer loss calculation, and designs an optimization method.

[0049] 2. The high-frequency transformer in the dual active bridge converter operating under three-way modulation has different current effective values ​​and transformer port voltages under different working conditions. The traditional design method fails to consider the specific waveforms at both ends of the transformer when it is working, resulting in inaccurate calculation of saturation flux density and transformer window area during design, which may cause saturation problems when the transformer is running. In the transformer manufacturing process, the winding is difficult to wind due to miscalculation of the window area. The high-frequency transformer design method in the dual active bridge converter provided by the present invention can effectively solve the above problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] 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.

[0051] Figure 1 A schematic flow chart of a method for designing a high frequency transformer in a dual active bridge converter provided by an embodiment of the present invention;

[0052] Figure 2 A typical application topology of a high-frequency transformer provided in an embodiment of the present invention;

[0053] Figure 3 A waveform diagram of Tr(t) provided in an embodiment of the present invention;

[0054] Figure 4 A flowchart of designing transformer parameters using the NSGA-II algorithm provided in an embodiment of the present invention;

[0055] Figure 5A schematic structural diagram of a high frequency transformer design system for a dual active bridge converter provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0056] 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.

[0057] See also Figure 1 , a method for designing a high frequency transformer in a dual active bridge converter provided in an embodiment of the present invention comprises:

[0058] Step 101: Combining the high-frequency transformer design theory with the dual active bridge operation principle, derive the transformer loss formula under three-phase shift modulation.

[0059] In one embodiment, step 101 includes:

[0060] Based on the loss of the unit core of the high-frequency transformer under non-sinusoidal excitation, it is deduced that when three-phase shift modulation is used, the core loss of the high-frequency transformer and the phase shift angle D in the right bridge arm are 3 relationship;

[0061] The high-frequency transformer winding loss is derived based on the winding AC resistance and effective value of the inductor current of the high-frequency transformer;

[0062] The conduction loss is taken as the loss of the switching devices of the dual active bridge converter in three-phase shift modulation;

[0063] According to the core loss of the high-frequency transformer and the phase shift angle D in the right bridge arm 3 The total loss is obtained by combining the relationship between the high-frequency transformer winding loss and the switching device loss;

[0064] Among them, the optimization expression of total loss is:

[0065] ;

[0066] In the formula, is the volume of the core, For the indivual The conduction loss, i.e. the loss of the switching device, is the core loss of the high-frequency transformer and the phase shift angle in the right bridge arm relationship, is the high frequency transformer winding loss.

[0067] It should be noted that the following is a principle description of step 101:

[0068] Typical application topologies of high frequency transformers are as follows: Figure 2 As shown, the voltage across the high-frequency transformer is directly related to the output voltage value and the internal phase shift angle of the right bridge arm. According to the IGSE formula, the loss of the unit magnetic core under non-sinusoidal excitation is:

[0069] ;

[0070] ;

[0071] Where P v is the core loss of the unit core, T is the period of excitation applied at both ends of the transformer, B(t) is the value of the magnetic flux density at time t, △B is the peak-to-peak value of the magnetic flux density, K, α, β are the coefficients of the core loss curve fitted according to the manufacturer.

[0072] Therefore, when TPS modulation (three-phase shift modulation, i.e. triple phase shift control method) is used, the core loss of the high-frequency transformer is related to the phase shift angle D in the right bridge arm. 3 The relationship is:

[0073] ;

[0074] Where D 3 is the inner phase angle of the right bridge arm, A e is the effective area of ​​the core, N p is the number of turns of the primary winding, U o is the DAB output voltage.

[0075] The high-frequency transformer winding loss is:

[0076] ;

[0077] In the formula, R ac is the winding AC resistance, I rms is the effective value of the inductor current. Under TPS modulation, I rms 2 It is expressed as:

[0078] ;

[0079] Where D 1 is the inner phase shift angle of the left bridge arm, D 2 is the outward shift phase angle between the bridge arms, V 1 、V 2 are the primary and secondary voltages of the transformer respectively, L is the series inductance, and the waveform of Tr(t) is as follows Figure 3 shown.

[0080] The DAB converter (dual active bridge converter) works under soft switching conditions through TPS modulation, so the switching loss can be ignored. The loss of the switching device mainly comes from the conduction loss, which is expressed as:

[0081] ;

[0082] Where P mosfet，k is the conduction loss of the kth MOSFET, R on，k is the on-resistance of the kth MOSFET.

[0083] Therefore, the total loss optimization expression is:

[0084] ;

[0085] Where V e is the volume of the magnetic core.

[0086] Step 102: Based on three-phase shift modulation, the relationship between the maximum magnetic flux density and the phase shift angle of the high-frequency transformer is obtained, so as to determine the magnetic flux density constraint condition.

[0087] It should be noted that, combined with three-phase shift modulation (TPS modulation), the relationship between the maximum magnetic flux density and the phase shift angle of the high-frequency transformer is:

[0088] ;

[0089] In the formula, B max N is the maximum magnetic flux density of the high-frequency transformer under given working conditions. s is the number of turns of the secondary winding.

[0090] Step 103: Obtain window area constraints according to the effective value of the high-frequency transformer current and in combination with three-phase shift modulation.

[0091] It should be noted that the effective values ​​of the primary and secondary sides of the transformer are Ip and Is respectively. Combined with TPS modulation, the window area constraint is:

[0092] ;

[0093] Where N p is the number of turns of the primary winding, K w is the window coefficient, and J is the current density.

[0094] Step 104: determine the optimization design target and constraint conditions of the high-frequency transformer under three-phase shift modulation according to the loss formula, magnetic density constraint conditions and window area constraint conditions, and use the NSGA-II algorithm to design the high-frequency transformer parameters.

[0095] It should be noted that, based on steps 101 to 103, the optimization design objectives and constraints of the high-frequency transformer under TPS modulation are:

[0096] ;

[0097] In the specific simulation, the NSGA-II algorithm is used to design the transformer parameters. The design process is as follows: Figure 4 shown.

[0098] A method for designing a high-frequency transformer in a dual active bridge converter provided in an embodiment of the present invention first combines the optimization of the high-frequency transformer with the operating principle of the DAB converter, and derives the expressions for the core loss and winding loss of the high-frequency transformer under TPS modulation, so that the efficiency calculation of the high-frequency transformer used in the DAB using TPS modulation is more accurate, thereby guiding the design of the high-frequency transformer. Furthermore, the present invention derives the magnetic density constraint and window area constraint under TPS modulation, so that the design of the saturation magnetic density value and window size is more accurate, avoiding the saturation of the high-frequency transformer core during operation due to design problems, and making the designed high-frequency transformer more compact.

[0099] The above is a method for designing a high frequency transformer in a dual active bridge converter provided in an embodiment of the present invention. The following is a system for designing a high frequency transformer in a dual active bridge converter provided in an embodiment of the present invention.

[0100] See also Figure 5 , a high frequency transformer design system for a dual active bridge converter provided in an embodiment of the present invention comprises:

[0101] The first analysis unit 201 is used to derive a loss formula of the transformer under three-phase shift modulation by combining the high-frequency transformer design theory with the dual active bridge operation principle.

[0102] The second analysis unit 202 is used to obtain the relationship between the maximum magnetic flux density and the phase shift angle of the high-frequency transformer based on three-phase shift modulation, so as to determine the magnetic flux density constraint condition.

[0103] The third analysis unit 203 is used to obtain the window area constraint according to the effective value of the high-frequency transformer current and in combination with the three-phase shift modulation.

[0104] The design unit 204 is used to determine the optimization design target and constraint conditions of the high-frequency transformer under three-phase shift modulation according to the loss formula, magnetic density constraint conditions and window area constraint conditions, and to design the parameters of the high-frequency transformer using the NSGA-II algorithm.

[0105] Furthermore, an embodiment of the present invention also provides a high frequency transformer design device for a dual active bridge converter, the device comprising a processor and a memory:

[0106] The memory is used to store program code and transmit the program code to the processor;

[0107] The processor is used to execute the steps of the method for designing a high-frequency transformer in a dual active bridge converter as described in the above method embodiment according to the instructions in the program code.

[0108] Furthermore, a computer-readable storage medium is provided in an embodiment of the present invention, and the computer-readable storage medium is used to store program code, and the program code is used to execute the high-frequency transformer design method for the dual active bridge converter described in the above method embodiment.

[0109] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0110] In the several embodiments provided by the present invention, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0111] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0112] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0113] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0114] 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 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 method for designing a high frequency transformer in a dual active bridge converter, characterized in that: include: Combining the high-frequency transformer design theory with the dual active bridge operation principle, the transformer loss formula under three-phase shift modulation is derived; Obtain the relationship between the maximum magnetic flux density and the phase shift angle of the high-frequency transformer, so as to determine the magnetic flux density constraint conditions; According to the effective value of high frequency transformer current and combined with three-phase shift modulation, the window area constraint is obtained; According to the loss formula, the magnetic density constraint condition and the window area constraint, the optimization design target and constraint condition of the high-frequency transformer under three-phase shift modulation are determined, and the parameters of the high-frequency transformer are designed by using the NSGA-II algorithm; Among them, the high-frequency transformer design theory combined with the dual active bridge operation principle derives the transformer loss formula under three-phase shift modulation, including: Based on the loss of the unit core of the high-frequency transformer under non-sinusoidal excitation, the relationship between the core loss of the high-frequency transformer and the phase shift angle D3 in the right bridge arm when three-phase shift modulation is adopted is derived; The high-frequency transformer winding loss is derived based on the winding AC resistance and effective value of the inductor current of the high-frequency transformer; The conduction loss is taken as the loss of the switching devices of the dual active bridge converter in three-phase shift modulation; The total loss is obtained according to the relationship between the core loss of the high-frequency transformer and the phase shift angle D3 in the right bridge arm, the winding loss of the high-frequency transformer and the loss of the switching device; Among them, the optimization expression of the total loss is: ； In the formula, is the volume of the core, For the indivual The conduction loss, that is, the loss of the switching device, is the core loss of the high-frequency transformer and the phase shift angle in the right bridge arm relationship, is the high frequency transformer winding loss; The expression of the window area constraint is: ； In the formula, is the number of turns of the primary winding, is the period of excitation applied across the high-frequency transformer, is the series inductor, , are the primary and secondary voltages of the transformer, is the inner phase shift angle of the left bridge arm, is the outward shift phase angle between the bridge arms, is the phase shift angle in the right bridge arm, For a certain moment, is the current density, is the window coefficient, A w is the window area, Tr is the function of time t.

2. The method for designing a high frequency transformer in a dual active bridge converter according to claim 1, characterized in that: The expression of the magnetic density constraint condition is: ； In the formula, is the saturation flux density of the core material, is the design margin, is the phase shift angle in the right bridge arm, is the period of excitation applied across the high-frequency transformer, is the output voltage of the dual active bridge converter, is the number of turns of the secondary winding, is the effective area of ​​the core.

3. The method for designing a high frequency transformer in a dual active bridge converter according to claim 2, characterized in that: The expressions of the optimization design objectives and constraints are: ； In the formula, is the volume of the core, For the indivual The conduction loss, that is, the loss of the switching device, is the core loss of the high-frequency transformer and the phase shift angle in the right bridge arm relationship, is the high frequency transformer winding loss; is the saturation flux density of the core material, is the design margin, is the phase shift angle in the right bridge arm, is the period of excitation applied across the high-frequency transformer, is the output voltage of the dual active bridge converter, is the number of turns of the secondary winding, is the effective area of ​​the core; is the number of turns of the primary winding, is the current density, is the window coefficient, , They are respectively the effective values ​​of the primary and secondary sides of the high-frequency transformer; is the rated power of the high frequency transformer, is the volume of the high-frequency transformer core, is the volume of high frequency transformer winding.

4. A dual active bridge converter medium and high frequency transformer design system, characterized in that: include: The first analysis unit is used to combine the high-frequency transformer design theory with the dual active bridge operation principle to derive the transformer loss formula under three-phase shift modulation; The second analysis unit is used to obtain the relationship between the maximum magnetic flux density and the phase shift angle of the high-frequency transformer, so as to determine the magnetic flux density constraint condition; A third analysis unit is used to obtain a window area constraint according to the effective value of the high-frequency transformer current and in combination with three-phase shift modulation; A design unit, used to determine the optimization design target and constraint conditions of the high-frequency transformer under three-phase shift modulation according to the loss formula, the magnetic density constraint condition and the window area constraint, and to design the parameters of the high-frequency transformer using the NSGA-II algorithm; Wherein, the first analysis unit is specifically used for: Based on the loss of the unit core of the high-frequency transformer under non-sinusoidal excitation, the relationship between the core loss of the high-frequency transformer and the phase shift angle D3 in the right bridge arm when three-phase shift modulation is adopted is derived; The high-frequency transformer winding loss is derived based on the winding AC resistance and effective value of the inductor current of the high-frequency transformer; The conduction loss is taken as the loss of the switching devices of the dual active bridge converter in three-phase shift modulation; The total loss is obtained according to the relationship between the core loss of the high-frequency transformer and the phase shift angle D3 in the right bridge arm, the winding loss of the high-frequency transformer and the loss of the switching device; Among them, the optimization expression of the total loss is: ； In the formula, is the volume of the core, For the indivual The conduction loss, that is, the loss of the switching device, is the core loss of the high-frequency transformer and the phase shift angle in the right bridge arm relationship, is the high frequency transformer winding loss; The expression of the window area constraint is: ； In the formula, is the number of turns of the primary winding, is the period of excitation applied across the high-frequency transformer, is the series inductor, , are the primary and secondary voltages of the transformer, is the inner phase angle of the left bridge arm, is the outward shift phase angle between the bridge arms, is the phase shift angle in the right bridge arm, For a certain moment, is the current density, is the window coefficient, A w is the window area, Tr is the function of time t.

5. The high frequency transformer design system for dual active bridge converter according to claim 4, characterized in that: The expressions of the optimization design objectives and constraints are: ； In the formula, is the volume of the core, For the indivual The conduction loss, that is, the loss of the switching device, is the core loss of the high-frequency transformer and the phase shift angle in the right bridge arm relationship, is the high frequency transformer winding loss; is the saturation flux density of the core material, is the design margin, is the phase shift angle in the right bridge arm, is the period of excitation applied across the high-frequency transformer, is the output voltage of the dual active bridge converter, is the number of turns of the secondary winding, is the effective area of ​​the core; is the number of turns of the primary winding, is the current density, is the window coefficient, , They are respectively the effective values ​​of the primary and secondary sides of the high-frequency transformer; is the rated power of the high frequency transformer, is the volume of the high-frequency transformer core, is the volume of high frequency transformer winding.

6. A dual active bridge converter medium and high frequency transformer design device, characterized in that: The device comprises a processor and a memory: The memory is used to store program code and transmit the program code to the processor; The processor is used to execute the high-frequency transformer design method for the dual active bridge converter according to any one of claims 1-3 according to the instructions in the program code.

7. A computer-readable storage medium, characterized in that: The computer-readable storage medium is used to store program codes, and the program codes are used to execute the method for designing a high-frequency transformer in a dual active bridge converter according to any one of claims 1 to 3.

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