Dual active bridge dc-dc converter hybrid half-frequency modulation method, system, device, and medium

Abstract

The application discloses a dual active bridge DC-DC converter hybrid half-frequency modulation method, system, device and medium, comprising the following steps: determining the working mode of the current working point of a dual active bridge DC-DC converter according to the transmission power p, input voltage V in and output voltage V o of the dual active bridge DC-DC converter; determining the type of modulation according to the working mode of the current working point of the dual active bridge DC-DC converter, wherein the type of modulation comprises three-phase shift (TPS) modulation, secondary-side half-frequency modulation, primary-side half-frequency modulation and double-side half-frequency modulation. The method, system, device and medium can effectively solve the problems of large inductance current stress and low efficiency of the DAB converter in a wide voltage range and a full power range.

Description

Technical Field

[0001] This invention belongs to the field of power electronics technology DC / DC converters, and relates to a hybrid half-frequency modulation method, system, device and medium for a dual active bridge DC-DC converter. Background Technology

[0002] In response to the carbon peaking and carbon neutrality strategic goals, DC microgrids and electric vehicle technologies have developed rapidly. Against this backdrop, bidirectional DC / DC converters, as crucial devices connecting DC buses of different voltage levels with various energy storage units, play a vital role, especially in energy flow management and optimized configuration, where converter performance is paramount. Among them, dual active bridge (DAB) converters have gradually become a focus of widespread attention due to their high power density, bidirectional power flow capability, and wide zero-voltage switching (ZVS) operating range. However, under the same operating voltage, the efficiency difference between full-load and light-load conditions for DAB converters can exceed 10%; furthermore, even with the same transmission power, the converter efficiency varies significantly under different operating voltage conditions. These issues severely restrict the promotion and industrialization of DAB converters in industrial applications.

[0003] The most common modulation strategy for DAB converters is Single Phase Shift (SPS). This strategy provides only one control variable, thus failing to offer optimization space under more complex operating conditions. When the input and output voltages are mismatched, the inductor current stress increases significantly, causing some switches to fail to maintain Zero-Voltage-Side (ZVS) conditions, thereby significantly reducing operating efficiency under light loads. To expand the ZVS operating range, reduce reactive power, and improve efficiency under light loads, the industry has successively proposed modulation strategies and optimization schemes such as Extended Phase Shift (EPS), Dual Phase Shift (DPS), and Triple Phase Shift (TPS). These strategies improve system performance to some extent, but when DAB converters operate over a wide voltage range, continuing to use these modulation strategies will lead to a significant increase in current stress at the same power level, negatively impacting the overall system efficiency. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a hybrid half-frequency modulation method, system, device and medium for dual active bridge DC-DC converters. This method, system, device and medium can effectively solve the problems of high inductor current stress and low efficiency of DAB converters in a wide voltage range and full power range.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In one aspect, the present invention provides a hybrid half-frequency modulation method for a dual active bridge DC-DC converter, comprising:

[0007] Based on the transmission power p and input voltage V of the dual active bridge DC-DC converter in and output voltage V o Determine the current operating mode of the dual active bridge DC-DC converter;

[0008] The modulation type is determined based on the operating mode of the current operating point of the dual active bridge DC-DC converter. The modulation types include three-phase shift (TPS) modulation, secondary-side half-frequency modulation, primary-side half-frequency modulation, and bilateral half-frequency modulation.

[0009] The further improvement of the hybrid half-frequency modulation method for dual active bridge DC-DC converters described in this invention lies in:

[0010] Furthermore, the per-unit values ​​of transmission power and per-unit values ​​of current stress for secondary-side half-frequency modulation, primary-side half-frequency modulation, and bilateral half-frequency modulation are shown in Table 1:

[0011] Table 1

[0012]

[0013]

[0014] In the secondary-side half-frequency modulation, the inward shift ratio of the primary-side H-bridge is D1, and the outward shift ratio between the primary and secondary sides is D2; in the primary-side half-frequency modulation, the inward shift ratio of the secondary-side H-bridge is D1, and the outward shift ratio between the primary and secondary sides is D2; in the bilateral half-frequency modulation, the outward shift ratio between the primary and secondary sides is D2. s This represents the voltage conversion ratio.

[0015] Furthermore, the phase shift combination and corresponding current stress I under TPS modulation over a wide voltage range and full power range. p As shown in Table 2:

[0016] Table 2

[0017]

[0018] Furthermore, the phase shift combination and current stress of the secondary half-frequency modulation are shown in Table 3:

[0019] Table 3

[0020]

[0021]

[0022] Furthermore, the shift ratio combination and current stress of primary-side half-frequency modulation and bilateral half-frequency modulation are shown in Table 4:

[0023] Table 4

[0024]

[0025] Furthermore, the boundary conditions for TPS modulation, secondary-side half-frequency modulation, and primary-side half-frequency modulation are shown in Table 5:

[0026] Table 5

[0027]

[0028] In a second aspect, the present invention provides a hybrid half-frequency modulation system for a dual active bridge DC-DC converter, comprising:

[0029] The judgment module is used to determine the transmission power p and input voltage V of the dual active bridge DC-DC converter. in and output voltage V o Determine the current operating mode of the dual active bridge DC-DC converter;

[0030] The modulation module is used to determine the modulation type according to the current operating mode of the dual active bridge DC-DC converter. The modulation type includes three-phase shift (TPS) modulation, secondary-side half-frequency modulation, primary-side half-frequency modulation, and bilateral half-frequency modulation.

[0031] The further improvement of the dual active bridge DC-DC converter hybrid half-frequency modulation system of the present invention is as follows:

[0032] Furthermore, the boundary conditions for TPS modulation, secondary-side half-frequency modulation, and primary-side half-frequency modulation are shown in Table 5:

[0033] Table 5

[0034]

[0035] In three aspects, the present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the hybrid half-frequency modulation method of the dual active bridge DC-DC converter.

[0036] In four aspects, the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the hybrid half-frequency modulation method for the dual active bridge DC-DC converter.

[0037] The present invention has the following beneficial effects:

[0038] When the hybrid half - frequency modulation method, system, device and medium of the dual - active - bridge DC - DC converter are specifically operated, the type of modulation is determined according to the working mode where the current working point of the dual - active - bridge DC - DC converter is located. The types of modulation include three - phase - shift (TPS) modulation, secondary - side half - frequency modulation, primary - side half - frequency modulation, and bilateral half - frequency modulation. The current stress between TPS and hybrid half - frequency modulation is compared. By determining the boundaries between the four modes, the hybrid half - frequency modulation of the DAB converter based on the minimum current stress not only reduces the conduction loss but also further improves the efficiency of the converter, solving the problems of large inductance current stress and low efficiency of the DAB converter within a wide voltage range and the full power range. Brief Description of the Drawings

[0039] The accompanying drawings forming a part of this invention are used to provide a further understanding of the invention. The schematic embodiments and descriptions thereof of the invention are used to explain the invention and do not constitute an improper limitation of the invention. In the drawings:

[0040] Figure 1 is the topology diagram of the DAB converter with a DC - blocking capacitor;

[0041] Figure 2 is the typical waveform diagram of secondary - side half - frequency modulation, where a represents the waveform diagram when D1 < D2; b is the waveform diagram when D1 > D2;

[0042] Figure 3 is the typical waveform diagram of primary - side half - frequency modulation, where a represents the waveform diagram when 0 < D1 + D2 < 1; b is the waveform diagram when D1 + D2 > 1;

[0043] Figure 4 is the typical waveform diagram of bilateral half - frequency modulation, where a represents the waveform diagram when 0 < D2 < 1; b is the waveform diagram when D2 > 1;

[0044] Figure 5 is the three - dimensional relationship diagram of current stress under four modes;

[0045] Figure 6 is the image of the four - mode region division;

[0046] Figure 7 is the mode - switching control block diagram;

[0047] Figure 8 is the experimental waveform diagram under the condition of operating point 1, where a is the experimental waveform diagram of TPS modulation under the condition of operating point 1, and b is the experimental waveform diagram of secondary - side half - frequency modulation under the condition of operating point 1;

[0048] Figure 9The following are experimental waveforms under the selected point 2 condition, where a is the TPS modulation experimental waveform under the selected point 2 condition, and b is the primary side half-frequency modulation experimental waveform under the selected point 2 condition.

[0049] Figure 10 The following are experimental waveforms under the selected point 3 condition: a is the TPS modulation experimental waveform under the selected point 3 condition, b is the secondary half-frequency modulation experimental waveform under the selected point 3 condition, and c is the primary half-frequency modulation experimental waveform under the selected point 3 condition.

[0050] Figure 11 The graphs are line graphs showing the changes in current stress and efficiency with power when k=2, with graph a showing the changes in current stress with power when k=2 and graph b showing the changes in efficiency with power when k=2. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0053] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0054] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0055] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0056] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0057] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0058] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0059] Example 1

[0060] refer to Figure 1 The hybrid half-frequency modulation method for dual active bridge DC-DC converters of the present invention includes the following steps:

[0061] Based on the transmission power p and input voltage V of the dual active bridge DC-DC converter in and output voltage V oDetermine the operating mode of the current operating point of the dual-active-bridge DC-DC converter, and determine the type of modulation according to the operating mode of the current operating point of the dual-active-bridge DC-DC converter. The types of modulation include triple-phase-shift (TPS) modulation, secondary-side half-frequency modulation, primary-side half-frequency modulation, and bilateral half-frequency modulation.

[0062] Figure 1 FIG. is the topological structure diagram of the DAB converter. The DAB converter consists of a primary-side support capacitor C1, a secondary-side support capacitor C2, a primary-side full-bridge circuit, a secondary-side full-bridge circuit, a high-frequency transformer T, an auxiliary inductor L, and a primary-secondary side DC-blocking capacitor C b and the primary-side full-bridge output voltage and the secondary-side full-bridge output voltage are V p and V s .

[0063] Reference Figures 2-4 , in the secondary-side half-frequency modulation, the internal phase-shift ratio of the primary H-bridge is D1, and the external phase-shift ratio between the primary and secondary sides is D2; in the primary-side half-frequency modulation, the internal phase-shift ratio of the secondary H-bridge is D1, and the external phase-shift ratio between the primary and secondary sides is D2; in the bilateral half-frequency modulation, the external phase-shift ratio between the primary and secondary sides is D2. According to the analysis of the typical waveforms, the transmission characteristics of the three modes are calculated respectively, including the normalized transmission power P * and the normalized current stress, the mode domain, and the necessary conditions for realizing soft switching. Among them, the expressions of each characteristic take their normalized values, and a new voltage conversion ratio k s =2k = 2V1 / V2 is introduced in the secondary-side half-frequency modulation; a new voltage conversion ratio k s =k / 2 = V1 / 2V2 is introduced in the primary-side half-frequency modulation.

[0064] Taking one case of the secondary-side half-frequency modulation as an example, that is, when D1 < D2, the expression of the inductor current at each moment is:

[0065]

[0066] The expression of the transmission power is calculated by combining the inductor current expressions at each moment with the inductor current expressions in each time period:

[0067]

[0068] For the convenience of calculation, the transmission power is normalized to obtain:

[0069]

[0070] Since the moment when the maximum inductor current appears is different according to k s , the current stress is divided into two cases according to k s , which are 0 < ks <1 and k s > 1, and the expressions of the per-unit values of their current stresses are respectively:

[0071]

[0072] And so on, using the same analysis and calculation method to calculate the three modulation modes respectively, and the per-unit values of the transmission power and the per-unit values of the current stress of the three modulation modes are calculated as shown in Table 1.

[0073] Table 1

[0074]

[0075] The phase shift ratio combinations and the corresponding current stresses under TPS modulation in a wide voltage range and the full power range are shown in Table 2.

[0076] Table 2

[0077]

[0078] Taking the low-power operation under the secondary half-frequency modulation as an example, at this time, the relationship of the phase shift ratio is 0 ≤ D2 < D1 < 1. According to the expressions of the per-unit values of its transmission power and current stress, the Lagrangian function is established as:

[0079]

[0080] It can be calculated that the phase shift ratio combination with the minimum current stress in this case is:

[0081]

[0082] And so on to the high-power section, the phase shift ratio combinations and current stresses of the secondary half-frequency modulation are calculated as shown in Table 3.

[0083] Table 3

[0084]

[0085] Similar methods can be used to summarize the phase shift ratio combinations and current stresses of the primary half-frequency modulation and the bilateral half-frequency modulation as shown in Table 4.

[0086] Table 4

[0087]

[0088] Taking reducing the current stress as the goal, on the basis of ensuring the transmission power, the four modes are compared and analyzed to optimize the current stress of the DAB converter in a wide voltage range and the full power range. First, draw the three-dimensional relationship diagram of the current stress of the four modes with the voltage conversion ratio and the per-unit value of the transmission power, as Figure 5As shown. To define the boundary conditions for switching between the four modes and obtain the operating range corresponding to the four modes, the 3D image is flipped to obtain its bottom view, as shown. Figure 6 As shown. From Figure 6 Analysis revealed that the entire operating range was divided into three regions, representing TPS modulation (region 1), secondary-side half-frequency modulation (region 2), and primary-side half-frequency modulation (region 3). By sampling points at the boundaries between modes and fitting the boundaries of the three regions, the boundary conditions between modes could be obtained, and the operating range corresponding to each mode could be determined, as shown in Table 5.

[0089] Table 5

[0090]

[0091] Figure 7 This is a block diagram for mode switching, where the transmission power p can be controlled by the output voltage V. o and output current I o Multiply to obtain. The mode switching section uses the transmission power p and input voltage V. in and output voltage V o Determine the current operating mode and use an appropriate modulation strategy to control the PWM wave output based on the corresponding mode.

[0092] Under the selected point 1 operating condition, the system parameters are k = 0.5, P * =0.25. According to the experiment Figure 8 The results show that the current stress in TPS control mode is 1.59A, while in primary-side half-frequency modulation mode, the current stress is significantly reduced to 0.633A. In contrast, secondary-side half-frequency modulation reduces the current stress by 60.18%. This result indicates that, under this operating condition, primary-side half-frequency modulation has a significant advantage in reducing current stress. For the operating condition at point 2, the system parameters are adjusted to k=2, P... * =0.25, experimental results are as follows Figure 9 As shown, the current stress reaches 3.06A in TPS control mode, while it decreases to 1.30A in primary-side half-frequency modulation mode. The comparison demonstrates that primary-side half-frequency modulation effectively reduces current stress by over 50%, further validating the superiority of this modulation method in reducing current stress. Under the condition of point 3, with parameters k = 1.2 and P... * =0.25, and its experimental waveform is as follows Figure 10As shown in the figure, a comparison of current stress reveals that the current stress under TPS control mode is lower than that under secondary-side half-frequency modulation, with a difference of 1.30A. Furthermore, compared to primary-side half-frequency modulation, the current stress under TPS control mode is even lower, reduced by 3.45A. This result is consistent with the theoretical analysis based on region division, further demonstrating that different modulation methods have significant differences in their impact on current stress under various operating conditions.

[0093] The above measured data show that the proposed hybrid half-frequency modulation effectively reduces the current stress of the DAB converter, and the mode division within the operating range is reasonable. To further verify the improvement in efficiency caused by modulation, sampling experiments on current stress and efficiency were conducted over the full power range at a fixed voltage conversion ratio. Figure 11 The measured data under the k=2 condition are presented. Hybrid half-frequency modulation significantly reduces current stress while improving converter efficiency.

[0094] Example 2

[0095] The dual active bridge DC-DC converter hybrid half-frequency modulation system of the present invention includes:

[0096] The judgment module is used to determine the transmission power p and input voltage V of the dual active bridge DC-DC converter. in and output voltage V o Determine the current operating mode of the dual active bridge DC-DC converter;

[0097] The modulation module is used to determine the modulation type according to the current operating mode of the dual active bridge DC-DC converter. The modulation type includes three-phase shift (TPS) modulation, secondary-side half-frequency modulation, primary-side half-frequency modulation, and bilateral half-frequency modulation.

[0098] The module division in this embodiment is illustrative and represents only one logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in each embodiment of this application can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0099] Example 3

[0100] A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the hybrid half-frequency modulation method for a dual active bridge DC-DC converter, for example, including: based on the transmission power p and input voltage V of the dual active bridge DC-DC converter... inand output voltage V o The system determines the current operating mode of the dual active bridge DC-DC converter; based on the current operating mode, it determines the modulation type, which includes three-phase shift modulation (TPS), secondary-side half-frequency modulation, primary-side half-frequency modulation, and bilateral half-frequency modulation. The memory may include main memory, such as high-speed random access memory, or non-volatile memory, such as at least one disk storage device. The processor, network interface, and memory are interconnected via an internal bus, which can be an industry-standard architecture bus, a peripheral component interconnection standard bus, or an extended industry-standard architecture bus. The bus can be categorized as an address bus, data bus, and control bus. The memory stores programs; specifically, the program may include program code, which includes computer operation instructions. The memory may include main memory and non-volatile memory, and provides instructions and data to the processor.

[0101] Example 4

[0102] A computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the hybrid half-frequency modulation method for the dual active bridge DC-DC converter, for example including: based on the transmission power p and input voltage V of the dual active bridge DC-DC converter... in and output voltage V o The system determines the current operating mode of the dual active bridge DC-DC converter; based on this mode, it determines the modulation type, which includes three-phase shift (TPS) modulation, secondary-side half-frequency modulation, primary-side half-frequency modulation, and bilateral half-frequency modulation. Specifically, the computer-readable storage medium includes, but is not limited to, volatile memory and / or non-volatile memory. The volatile memory may include random access memory (RAM) and / or cache memory, etc. The non-volatile memory may include read-only memory (ROM), hard disk, flash memory, optical disk, magnetic disk, etc.

[0103] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0104] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0105] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0106] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0107] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0108] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0109] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A hybrid half-frequency modulation method for a dual active bridge DC-DC converter, characterized in that, include: Based on the transmission power of the dual active bridge DC-DC converter p、 Input voltage V in and output voltage V o Determine the current operating mode of the dual active bridge DC-DC converter; The modulation type is determined based on the operating mode of the current operating point of the dual active bridge DC-DC converter. The modulation types include three-phase shift TPS modulation, secondary-side half-frequency modulation, primary-side half-frequency modulation, and bilateral half-frequency modulation. The per-unit values ​​of transmission power and per-unit values ​​of current stress for secondary-side half-frequency modulation, primary-side half-frequency modulation, and bilateral half-frequency modulation are shown in Table 1. Table 1 In the secondary-side half-frequency modulation, the primary-side H-bridge shift ratio is... D 1. The ratio of the outward shift between the primary and secondary sides is... D 2; In primary-side half-frequency modulation, the secondary-side H-bridge inward shift ratio is D 1. The ratio of the outward shift between the primary and secondary sides is... D 2; In bilateral half-frequency modulation, the ratio of the outward shift between the primary and secondary sides is D 2, k s This represents the voltage conversion ratio.

2. The hybrid half-frequency modulation method for a dual active bridge DC-DC converter according to claim 1, characterized in that, Phase shift combination and corresponding current stress under TPS modulation over a wide voltage range and full power range As shown in Table 2: Table 2 3. The hybrid half-frequency modulation method for a dual active bridge DC-DC converter according to claim 1, characterized in that, The phase shift combination and current stress of the secondary half-frequency modulation are shown in Table 3: Table 3 4. The hybrid half-frequency modulation method for a dual active bridge DC-DC converter according to claim 1, characterized in that, The phase shift combinations and current stresses of primary-side half-frequency modulation and bilateral half-frequency modulation are shown in Table 4: Table 4 5. The hybrid half-frequency modulation method for a dual active bridge DC-DC converter according to claim 1, characterized in that, The boundary conditions for TPS modulation, secondary-side half-frequency modulation, and primary-side half-frequency modulation are shown in Table 5: Table 5 6. A hybrid half-frequency modulation system for a dual active bridge DC-DC converter, characterized in that, include: The judgment module is used to determine the transmission power of the dual active bridge DC-DC converter. p、 Input voltage V in and output voltage V o Determine the current operating mode of the dual active bridge DC-DC converter; The modulation module is used to determine the modulation type according to the current operating mode of the dual active bridge DC-DC converter. The modulation type includes three-phase shift TPS modulation, secondary-side half-frequency modulation, primary-side half-frequency modulation, and bilateral half-frequency modulation. The per-unit values ​​of transmission power and per-unit values ​​of current stress for secondary-side half-frequency modulation, primary-side half-frequency modulation, and bilateral half-frequency modulation are shown in Table 1. Table 1 In the secondary-side half-frequency modulation, the primary-side H-bridge shift ratio is... D 1. The ratio of the outward shift between the primary and secondary sides is... D 2; In primary-side half-frequency modulation, the secondary-side H-bridge inward shift ratio is D 1. The ratio of the outward shift between the primary and secondary sides is... D 2; In bilateral half-frequency modulation, the ratio of the outward shift between the primary and secondary sides is D 2, k s This represents the voltage conversion ratio.

7. The hybrid half-frequency modulation system of the dual active bridge DC-DC converter according to claim 6, characterized in that, The boundary conditions for TPS modulation, secondary-side half-frequency modulation, and primary-side half-frequency modulation are shown in Table 5: Table 5 8. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the hybrid half-frequency modulation method for the dual active bridge DC-DC converter as described in any one of claims 1-5.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the hybrid half-frequency modulation method for the dual active bridge DC-DC converter as described in any one of claims 1-5.

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