Direct-current converter, control method thereof and power conversion system

Abstract

The embodiment of the invention provides a direct-current converter, a control method thereof and a power conversion system. The DC converter comprises: a plurality of current-mode dual-active bridge type conversion modules; wherein the current-mode dual-active bridge type conversion module comprises a primary side full-bridge circuit, a transformer and a secondary side full-bridge circuit; wherein the low-voltage sides of the plurality of current-mode dual-active bridge type conversion modules are mutually connected in parallel, and the direct-current converter comprises a common clamping capacitor shared by the plurality of current-mode dual-active bridge type conversion modules. By sharing the clamping capacitor, the loss of a switching tube in the low-voltage side of the current-mode dual-active bridge type conversion module is reduced, and the service life of the direct-current converter can be prolonged to a certain extent.

Description

Technical Field

[0001] The embodiments in this specification relate to the field of power electronics technology, specifically to a DC-DC converter and its control method, and a power conversion system. Background Technology

[0002] The current-fed dual active bridge (CFDAB) converter module, mainly evolved from the dual active bridge (DAB) converter, is a type of DC-DC converter module. The current-fed dual active bridge converter module has advantages such as low current ripple, wide voltage gain range, and ease of soft-switching.

[0003] However, in related technologies, the lifespan of current-mode dual active bridge converter modules in electronic devices is relatively short. Summary of the Invention

[0004] This specification provides a DC-DC converter and its control method, as well as a power conversion system, through several embodiments, which can improve the service life of current-type dual active bridge modules to a certain extent.

[0005] In a first aspect, this specification provides a DC-DC converter, comprising: multiple current-mode dual active bridge converter modules; wherein each current-mode dual active bridge converter module includes a primary-side full-bridge circuit, a transformer, and a secondary-side full-bridge circuit; wherein the low-voltage sides of the multiple current-mode dual active bridge converter modules are connected in parallel, and the DC-DC converter includes a common clamping capacitor shared by the multiple current-mode dual active bridge converter modules.

[0006] Optionally, the primary-side full-bridge circuit of the current-type dual active bridge converter module includes a first primary-side bridge arm and a second primary-side bridge arm, with an upper bridge arm output terminal and a lower bridge arm output terminal between the first primary-side bridge arm and the second primary-side bridge arm; wherein, the common clamping capacitor is connected between the upper bridge arm output terminal and the lower bridge arm output terminal.

[0007] Optionally, there may be multiple shared clamping capacitors, which are connected in parallel between the upper bridge arm output terminal and the lower bridge arm output terminal.

[0008] Optionally, the DC-DC converter includes a controller; the primary-side full-bridge circuit of the current-mode dual active bridge converter module includes a first primary-side bridge arm and a second primary-side bridge arm; the plurality of current-mode dual active bridge converter modules include a first current-mode dual active bridge converter module and a second current-mode dual active bridge converter module; the low-voltage side of the first current-mode dual active bridge converter module and the low-voltage side of the second current-mode dual active bridge converter module share a first DC inductor and a second DC inductor; the controller can respectively control the upper bridge arm of the first primary-side bridge arm and the lower bridge arm of the second primary-side bridge arm in the first current-mode dual active bridge converter module and the second current-mode dual active bridge converter module to be electrically connected, so that the positive current of the DC source connected to the DC-DC converter is positive. The first circuit is formed by connecting the positive terminal of the DC source, the first DC inductor, the primary winding of the transformer in the first current-type dual active bridge converter module, and the lower arm of the second primary side bridge arm in the first current-type dual active bridge converter module to the negative terminal of the DC source. A second circuit is formed by connecting the positive terminal of the DC source, the first DC inductor, the primary winding of the transformer in the second current-type dual active bridge converter module, and the lower arm of the second primary side bridge arm in the second current-type dual active bridge converter module to the negative terminal of the DC source. A third circuit is formed by connecting the positive terminal of the DC source, the first DC inductor, the upper arm of the first primary side bridge arm in the first current-type dual active bridge converter module, and the common clamping capacitor to the negative terminal of the DC source. A circuit is formed by connecting the positive terminal of the DC source, the first DC inductor, the upper arm of the first primary side bridge arm in the second current-type dual active bridge converter module, and the common clamping capacitor to the negative terminal of the DC source; or, the controller can control the lower arm of the first primary side bridge arm and the upper arm of the second primary side bridge arm in the first current-type dual active bridge converter module and the second current-type dual active bridge converter module to be electrically connected, so that the positive terminal of the DC source connected to the DC converter, the second DC inductor, the primary winding of the transformer in the first current-type dual active bridge converter module, the lower arm of the first primary side bridge arm in the first current-type dual active bridge converter module, and the negative terminal of the DC source are connected to the negative terminal of the DC source, forming a fourth circuit; The system comprises five circuits, and a sixth circuit formed by connecting the positive terminal of the DC source, the second DC inductor, the primary winding of the transformer in the second current-type dual active bridge converter module, the lower arm of the first primary side bridge arm in the second current-type dual active bridge converter module to the negative terminal of the DC source; a seventh circuit formed by connecting the positive terminal of the DC source, the second DC inductor, the upper arm of the second primary side bridge arm in the first current-type dual active bridge converter module, and the common clamping capacitor to the negative terminal of the DC source; and an eighth circuit formed by connecting the positive terminal of the DC source, the second DC inductor, the upper arm of the second primary side bridge arm in the second current-type dual active bridge converter module, and the common clamping capacitor to the negative terminal of the DC source.

[0009] Optionally, the DC-DC converter includes a controller; the primary-side full-bridge circuit of the current-mode dual active bridge converter module includes a first primary-side bridge arm and a second primary-side bridge arm; the plurality of current-mode dual active bridge converter modules include a third current-mode dual active bridge converter module and a fourth current-mode dual active bridge converter module; the low-voltage side of the third current-mode dual active bridge converter module is connected to a third DC inductor and a fourth DC inductor; the low-voltage side of the fourth current-mode dual active bridge converter module is connected to a fifth DC inductor and a sixth DC inductor; the controller controls the upper bridge arm of the first primary-side bridge arm and the lower primary-side bridge arm of the third current-mode dual active bridge converter module. The lower arm of the second primary-side bridge arm is electrically turned on, forming a ninth circuit from the positive terminal of the DC source connected to the DC converter, the third DC inductor, the primary winding of the transformer in the third current-type dual active bridge converter module, the lower arm of the second primary-side bridge arm in the first current-type dual active bridge converter module, to the negative terminal of the DC source; and forming a tenth circuit from the positive terminal of the DC source, the third DC inductor, the upper arm of the first primary-side bridge arm in the third current-type dual active bridge converter module, and the common clamping capacitor to the negative terminal of the DC source; or, the controller controls the third current-type dual active bridge converter... In the module, the lower arm of the first primary-side bridge arm and the upper arm of the second primary-side bridge arm are electrically connected, forming an eleventh circuit from the positive terminal of the DC source, the fourth DC inductor, the primary winding of the transformer in the third current-type dual active bridge converter module, the lower arm of the first primary-side bridge arm in the third current-type dual active bridge converter module to the negative terminal of the DC source; and forming a twelfth circuit from the positive terminal of the DC source, the third DC inductor, the upper arm of the second primary-side bridge arm in the third current-type dual active bridge converter module, and the common clamping capacitor to the negative terminal of the DC source; or, the controller controls the fourth current-type In the dual active bridge converter module, the upper arm of the first primary side bridge arm and the lower arm of the second primary side bridge arm are electrically connected, so that the positive terminal of the DC source connected to the DC converter, the fifth DC inductor, the primary winding of the transformer in the fourth current-type dual active bridge converter module, the lower arm of the second primary side bridge arm in the fourth current-type dual active bridge converter module, and the negative terminal of the DC source form a thirteenth circuit; and the positive terminal of the DC source, the fifth DC inductor, the upper arm of the first primary side bridge arm in the fourth current-type dual active bridge converter module, the common clamping capacitor, and the negative terminal of the DC source form a fourteenth circuit.Alternatively, the controller electrically connects the lower arm of the first primary side bridge arm and the upper arm of the second primary side bridge arm in the fourth current-type dual active bridge converter module, thereby forming a fifteenth circuit from the positive terminal of the DC source, the sixth DC inductor, the primary winding of the transformer in the fourth current-type dual active bridge converter module, the lower arm of the first primary side bridge arm in the fourth current-type dual active bridge converter module to the negative terminal of the DC source; and forms a sixteenth circuit from the positive terminal of the DC source, the sixth DC inductor, the upper arm of the second primary side bridge arm in the fourth current-type dual active bridge converter module, and the common clamping capacitor to the negative terminal of the DC source.

[0010] Optionally, there may be multiple shared clamping capacitors, and the number of shared clamping capacitors may be greater than or equal to the number of current-mode dual active bridge converter modules among the multiple current-mode dual active bridge converter modules.

[0011] Optionally, the DC-DC converter includes a first output mode and / or a second output mode; wherein, when the DC-DC converter is in the first output mode, the secondary full-bridge circuits of the plurality of current-source dual active bridge converter modules are connected in series to output power externally; when the DC-DC converter is in the second output mode, the secondary full-bridge circuits of the plurality of current-source dual active bridge converter modules are connected in parallel to output power externally.

[0012] Optionally, the controller of the DC-DC converter is configured to receive a mode control signal from a power conversion device connected to the DC-DC converter; the mode control signal includes a first signal or a second signal; when the received mode control signal is the first signal, the controller controls the DC-DC converter to be in the first output mode; the power conversion device applicable to the DC-DC converter in the first output mode is a three-phase power conversion device; or, when the received mode control signal is the second signal, the controller controls the DC-DC converter to be in the second output mode; the power conversion device applicable to the DC-DC converter in the second output mode is a single-phase power conversion device.

[0013] Optionally, the DC-DC converter integrates an output control program; the controller of the DC-DC converter executes the output control program to ensure that the current output by the secondary full-bridge circuit of the plurality of current-source dual active bridge converter modules is equal when the DC-DC converter is in the first output mode; or, the controller of the DC-DC converter executes the output control program to ensure that the voltage output by the secondary full-bridge circuit of the plurality of current-source dual active bridge converter modules is equal when the DC-DC converter is in the second output mode.

[0014] Secondly, this specification provides a power conversion system, which includes a DC-DC converter as described above.

[0015] Thirdly, this specification provides a control method for a DC-DC converter, the method comprising: controlling multiple current-type dual active bridge converter modules connected in parallel on the low-voltage side to share a common clamping capacitor during operation.

[0016] Optionally, the primary-side full-bridge circuit of the current-mode dual active bridge converter module includes a first primary-side bridge arm and a second primary-side bridge arm; the plurality of current-mode dual active bridge converter modules include a first current-mode dual active bridge converter module and a second current-mode dual active bridge converter module; the low-voltage side of the first current-mode dual active bridge converter module and the low-voltage side of the second current-mode dual active bridge converter module share a first DC inductor and a second DC inductor; the step of controlling the plurality of current-mode dual active bridge converter modules connected in parallel on the low-voltage side to share a common clamping capacitor during operation includes: respectively controlling the upper bridge arm of the first primary-side bridge arm and the lower bridge arm of the second primary-side bridge arm in the first current-mode dual active bridge converter module and the second current-mode dual active bridge converter module. Electrical conduction is achieved, forming a first circuit from the positive terminal of the DC source connected to the DC converter, the first DC inductor, the primary winding of the transformer in the first current-type dual active bridge converter module, the lower arm of the second primary side bridge arm in the first current-type dual active bridge converter module, to the negative terminal of the DC source; and forming a second circuit from the positive terminal of the DC source, the first DC inductor, the primary winding of the transformer in the second current-type dual active bridge converter module, the lower arm of the second primary side bridge arm in the second current-type dual active bridge converter module, to the negative terminal of the DC source; and forming a second circuit from the positive terminal of the DC source, the first DC inductor, the upper arm of the first primary side bridge arm in the first current-type dual active bridge converter module, and the common clamp. A capacitor is connected to the negative terminal of the DC source to form a third circuit, and the positive terminal of the DC source, the first DC inductor, the upper arm of the first primary side bridge arm in the second current-type dual active bridge converter module, and the common clamping capacitor are connected to the negative terminal of the DC source to form a fourth circuit; or, the lower arm of the first primary side bridge arm and the upper arm of the second primary side bridge arm in the first current-type dual active bridge converter module and the second current-type dual active bridge converter module are electrically connected, so that the positive terminal of the DC source connected to the DC converter, the second DC inductor, the primary winding of the transformer in the first current-type dual active bridge converter module, and the lower arm of the first primary side bridge arm in the first current-type dual active bridge converter module are connected to the negative terminal of the DC source to form a fourth circuit. The system forms a fifth circuit by connecting the positive terminal of the DC source, the second DC inductor, the primary winding of the transformer in the second current-type dual active bridge converter module, and the lower arm of the first primary side bridge arm in the second current-type dual active bridge converter module to the negative terminal of the DC source, forming a sixth circuit. It also forms a seventh circuit by connecting the positive terminal of the DC source, the first DC inductor, the upper arm of the second primary side bridge arm in the first current-type dual active bridge converter module, and the common clamping capacitor to the negative terminal of the DC source, forming a seventh circuit. Finally, it forms an eighth circuit by connecting the positive terminal of the DC source, the second DC inductor, the upper arm of the second primary side bridge arm in the second current-type dual active bridge converter module, and the common clamping capacitor to the negative terminal of the DC source.

[0017] Optionally, the primary-side full-bridge circuit of the current-mode dual active bridge converter module includes a first primary-side bridge arm and a second primary-side bridge arm; the plurality of current-mode dual active bridge converter modules include a third current-mode dual active bridge converter module and a fourth current-mode dual active bridge converter module; the low-voltage side of the third current-mode dual active bridge converter module is connected to a third DC inductor and a fourth DC inductor; the low-voltage side of the fourth current-mode dual active bridge converter module is connected to a fifth DC inductor and a sixth DC inductor; the step of controlling the plurality of current-mode dual active bridge converter modules connected in parallel on the low-voltage side to share a common clamping capacitor during operation includes: controlling the first current... In a dual-active bridge converter module, the upper arm of the first primary side bridge arm and the lower arm of the second primary side bridge arm are electrically connected, forming a ninth circuit from the positive terminal of the DC source connected to the DC converter, the third DC inductor, the primary winding of the transformer in the first current-type dual-active bridge converter module, the lower arm of the second primary side bridge arm in the first current-type dual-active bridge converter module, to the negative terminal of the DC source; and forming a tenth circuit from the positive terminal of the DC source, the third DC inductor, the upper arm of the first primary side bridge arm in the first current-type dual-active bridge converter module, the common clamping capacitor, to the negative terminal of the DC source; or, controlling... In the first current-type dual active bridge converter module, the lower arm of the first primary side bridge arm and the upper arm of the second primary side bridge arm are electrically connected, forming a ninth circuit from the positive terminal of the DC source, the fourth DC inductor, the primary winding of the transformer in the first current-type dual active bridge converter module, the lower arm of the first primary side bridge arm in the first current-type dual active bridge converter module to the negative terminal of the DC source; and forming a tenth circuit from the positive terminal of the DC source, the third DC inductor, the upper arm of the second primary side bridge arm in the first current-type dual active bridge converter module, and the common clamping capacitor to the negative terminal of the DC source; or, controlling the first In the dual-current-type active bridge converter module, the upper arm of the first primary side bridge arm and the lower arm of the second primary side bridge arm are electrically connected, so that the positive terminal of the DC source connected to the DC converter, the fifth DC inductor, the primary winding of the transformer in the second current-type active bridge converter module, the lower arm of the second primary side bridge arm in the second current-type active bridge converter module, and the negative terminal of the DC source form an eleventh circuit; and the positive terminal of the DC source, the fifth DC inductor, the upper arm of the first primary side bridge arm in the second current-type active bridge converter module, the common clamping capacitor, and the negative terminal of the DC source form a twelfth circuit.Alternatively, the lower arm of the first primary side bridge arm and the upper arm of the second primary side bridge arm in the second current-type dual active bridge converter module are electrically connected, forming a thirteenth circuit from the positive terminal of the DC source, the sixth DC inductor, the primary winding of the transformer in the second current-type dual active bridge converter module, the lower arm of the first primary side bridge arm in the second current-type dual active bridge converter module to the negative terminal of the DC source; and forming a fourteenth circuit from the positive terminal of the DC source, the sixth DC inductor, the upper arm of the second primary side bridge arm in the second current-type dual active bridge converter module, the common clamping capacitor to the negative terminal of the DC source.

[0018] Optionally, the method further includes: controlling the DC converter to be in a first output mode or a second output mode; wherein, when the DC converter is in the first output mode, the secondary full-bridge circuits of the plurality of current-source dual active bridge converter modules are connected in series to output power externally; when the DC converter is in the second output mode, the secondary full-bridge circuits of the plurality of current-source dual active bridge converter modules are connected in parallel to output power externally.

[0019] Optionally, the step of controlling the DC-DC converter to be in a first output mode or a second output mode includes: receiving a mode control signal from a power conversion device connected to the DC-DC converter; wherein the mode control signal includes a first signal or a second signal; when the received mode control signal is the first signal, controlling the DC-DC converter to be in the first output mode; wherein the power conversion device to which the DC-DC converter is suitable in the first output mode is a three-phase power conversion device; or, when the received mode control signal is the second signal, controlling the DC-DC converter to be in the second output mode; wherein the power conversion device to which the DC-DC converter is suitable in the second output mode is a single-phase power conversion device.

[0020] In the various embodiments provided in this specification, a common clamping capacitor is provided between the low-voltage sides of multiple current-type dual active bridge converter modules connected in parallel. This avoids the problem in related technologies where the clamping voltages differ between the low-voltage sides of multiple current-type dual active bridge converter modules, causing the clamping capacitor to form a loop through the switching transistor, thus increasing the conduction loss of the switching transistor. This improves the service life of the current-type dual active bridge module. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of a circuit topology for a DC-DC converter provided as an embodiment of this specification.

[0023] Figure 2 This is a schematic diagram of a circuit topology for a DC-DC converter provided as an embodiment of this specification.

[0024] Figure 3 This is a schematic diagram of a circuit topology for a DC-DC converter provided as an embodiment of this specification.

[0025] Figure 4 This is a schematic diagram of a circuit topology for a DC-DC converter provided as an embodiment of this specification.

[0026] Figure 5 This is a schematic diagram of a circuit topology for a DC-DC converter provided as an embodiment of this specification.

[0027] Figure 6 This is a schematic diagram of a circuit topology for a DC-DC converter provided as an embodiment of this specification.

[0028] Figure 7 This is a schematic diagram of a circuit topology for a DC-DC converter provided as an embodiment of this specification.

[0029] Figure 8 This is a schematic diagram of a power conversion system provided as an embodiment of this specification. Detailed Implementation

[0030] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0031] In the description of the embodiments of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0032] Please see Figure 1 , Figure 1 This specification provides a topology for a DC-DC converter. For example... Figure 1 As shown, the DC-DC converter includes two current-source dual active bridge modules. The low-voltage side of each current-source dual active bridge module includes a primary-side full-bridge circuit, a clamping capacitor, and the primary winding of a transformer. Switches Q1, Q2, Q3, and Q4 constitute the primary-side full-bridge circuit of one current-source dual active bridge module. C 01 This is the clamping capacitor for the current-mode dual active bridge module. Switches Q1', Q2', Q3', and Q4' constitute the primary-side full-bridge circuit of another current-mode dual active bridge module. C 02 This is the clamping capacitor for the current-mode dual active bridge module. Specifically, the low-voltage sides of the two current-mode dual active bridge modules are connected in parallel and share two DC inductors L. dc01 L dc02 Among them, L dc01 L dc02 Together with switching transistors Q1, Q2, Q3, Q4, and Q1', Q2', Q3', Q4', they form two current-mode dual active bridge module low-voltage side buck-boost circuits.

[0033] Each current-mode dual active bridge module's high-voltage side includes the transformer's secondary winding, a secondary full-bridge circuit, and an output filter capacitor. Specifically, the switching transistor Q... 11 Q 12 Q 13 Q 14 and Q 11 '、Q 12 '、Q 13 '、Q 14 These respectively constitute the secondary full-bridge circuits on the high-voltage side of two current-type dual active bridge modules.

[0034] V bat V represents the input voltage of the DC source on the low-voltage side of the DC-DC converter. bus This indicates the output voltage at the high-voltage side of the DC-DC converter. The DC source can be, but is not limited to, photovoltaic panels, photovoltaic strings formed by multiple photovoltaic panels, or energy storage systems.

[0035] The low-voltage side of the current-mode dual active bridge module is connected by resistor R1 and switch S. r1 and S r2 The low-voltage side soft-start circuit is connected to a DC source.

[0036] The high-voltage side of the current-type dual active bridge module is connected to the high-voltage output terminal of the DC-DC converter via an output switching circuit composed of relays K3, K4, and K5. The DC-DC converter can switch between series or parallel connections between the high-voltage sides of the two current-type dual active bridge modules by controlling the closing or opening of the switches in the switching circuit, so that V bus It can adapt to the voltage requirements of both single-phase and three-phase systems. Similarly, the high-voltage side of the DC-DC converter is also connected to a high-voltage side soft-start circuit consisting of resistor R2, switches K1 and K2.

[0037] The current-mode dual active bridge module can control the switching transistors on the low-voltage side of the current-mode dual active bridge module through a control signal with a duty cycle, so as to control the output voltage on the low-voltage side, so that the subsequent dual active bridge (DAB) circuit always operates in a voltage matching state of M=1. During power transmission, Vc=V1 / (1-D)=V2 / n, where n is the turns ratio of the high-voltage side to the low-voltage side, and D is the duty cycle of the control signal.

[0038] Clamping capacitors can absorb voltage spikes in a circuit, reducing the impact of these spikes on electronic components. However, because multiple current-mode dual active bridge modules each have independently installed clamping capacitors on the low-voltage side, if the clamping voltages across these individual clamping capacitors are inconsistent, a loop will form between the clamping capacitors through the switching transistors. This causes additional losses to the switching transistors, reducing their lifespan. Specifically, taking... Figure 1 Taking the DC-DC converter shown as an example, each of the two current-source dual active bridge modules has a clamping capacitor on its low-voltage side, i.e. Figure 1 C in 01 and C 02 For example, in the clamping capacitor C 01 The clamping voltage is greater than the clamping capacitance C. 02 Under clamping voltage conditions, it may form as follows Figure 1 The circuit shown can cause some damage to the switching transistors and reduce the lifespan of the current-type dual active bridge module.

[0039] Therefore, it is necessary to provide a DC-DC converter that can improve the service life of current-mode dual active bridge modules to a certain extent.

[0040] Please see Figure 2One embodiment of this specification provides a DC-DC converter 10, including multiple current-source dual active bridge converter modules. Each current-source dual active bridge converter module includes a primary-side full-bridge circuit, a secondary-side full-bridge circuit, and a transformer. Specifically, the DC-DC converter 10 includes a first current-source dual active bridge converter module 11 and a second current-source dual active bridge converter module 12. The primary-side full-bridge circuit is connected to the primary winding of the transformer on the low-voltage side, and the secondary-side full-bridge circuit is connected to the secondary winding of the transformer on the high-voltage side. Power transfer between the primary-side and secondary-side full-bridge circuits is achieved through the transformer.

[0041] The primary-side full-bridge circuit of the first current-type dual active bridge converter module 11 includes: switching transistors S1, S2, S3, and S4. Among them, switching transistors S1, S2, S3, and S4 are connected to the first DC inductor L in the DC converter 10. dc1 Or the second DC inductor L dc2 This constitutes the buck-boost circuit on the low-voltage side. The secondary-side full-bridge circuit of the first current-type dual active bridge converter module 11 includes: four switching transistors S... 11 S 12 S 13 S 14 .

[0042] The primary-side full-bridge circuit of the second current-source dual active bridge converter module 12 includes switching transistors S1', S2', S3', and S4'. The second current-source dual active bridge converter module 12 shares the first DC inductor L in the DC converter 10 with the first current-source dual active bridge converter module 11. dc1 Or the second DC inductor L dc2 This forms a step-up / step-down circuit. The secondary full-bridge circuit of the second current-type dual active bridge converter module 12 includes four switching transistors S. 11 '、S 12 '、S 13 '、S 14 '.

[0043] In this embodiment, the input voltage of the low-voltage side input DC source of the DC converter 10 is V. bat The output voltage at the high-voltage side output terminal is V. bus In some embodiments, similar to the aforementioned DC-DC converter, the low-voltage side of the first current-type dual active bridge module 11 and the second current-type dual active bridge module 12 can also be connected via a resistor R1 and a switch S. r1 and S r2 The low-voltage side soft-start circuit is connected to the low-voltage side input DC source of the DC-DC converter. In some embodiments, the high-voltage side output terminals of the first current-type dual active bridge module 11 and the second current-type dual active bridge module 12 can also be connected to a high-voltage side soft-start circuit consisting of resistor R2, switches K1 and K2.

[0044] It should be noted that the number of current-type dual active bridge converter modules is not limited to two; other numbers, such as three or four, can also be used, and can be flexibly set according to the needs of actual applications.

[0045] In this embodiment, the low-voltage sides of multiple current-type dual active bridge converter modules are connected in parallel. Specifically, as shown below... Figure 2 As shown, the low-voltage side of the first current-source dual active bridge converter module 11 is connected in parallel with the low-voltage side of the second current-source dual active bridge converter module 12. It can be understood that when using a larger number of current-source dual active bridge converter modules, the low-voltage sides of each current-source dual active bridge converter module can also be connected in parallel in a similar manner.

[0046] In this embodiment, the DC-DC converter 10 further includes a shared clamping capacitor C0 shared by multiple current-mode dual active bridge converter modules. The shared clamping capacitor C0 is used to stabilize the low-side voltage of the multiple current-mode dual active bridge converter modules. The number of shared clamping capacitors is not limited to one; in some embodiments, the number of shared clamping capacitors can be multiple, for example... Figure 3 The system uses two shared clamping capacitors, C0 and C1. The first current-source dual active bridge converter module and the second current-source dual active bridge converter module share these two shared clamping capacitors C0 and C1, and C0 and C1 are connected in parallel. Of course, the number of shared clamping capacitors can also be three or four, etc. When there are multiple shared clamping capacitors, they are connected in parallel so that multiple shared clamping capacitors can be used together. For example... Figure 4 The two current-mode dual active bridge converter modules share three common clamping capacitors C0, C1 and C2, and the common clamping capacitors C0, C1 and C2 are connected in parallel.

[0047] In some embodiments, the number of shared clamping capacitors is greater than or equal to the number of current-mode dual active bridge converter modules. Specifically, for example, if two current-mode dual active bridge converter modules are used in the DC-DC converter, the number of shared clamping capacitors can be two. When the number of shared clamping capacitors is the same as the number of current-mode dual active bridge converter modules in the DC-DC converter, the capacitance of each shared clamping capacitor can be equal to... Figure 1 Each clamping capacitor has a similar capacitance, thus the shared clamping capacitor capacity is suitable for the same number of current-mode dual active bridge converter modules. In some embodiments, where the number of shared clamping capacitors is greater than the number of current-mode dual active bridge converter modules in the DC-DC converter, the increased number of shared clamping capacitors results in more dispersed heat generation during operation compared to embodiments with fewer shared clamping capacitors, which helps reduce the wear and tear on the shared clamping capacitors.

[0048] In some embodiments, the number of shared clamping capacitors can be only one. In this case, multiple current-source dual active bridge converter modules share this single shared clamping capacitor. Since only one shared clamping capacitor is used, there is no issue of voltage differences between multiple shared clamping capacitors leading to loops through the switching transistors, thus avoiding additional losses to the switching transistors. In some embodiments, the number of shared clamping capacitors can be multiple. In this case, these multiple clamping capacitors are connected in parallel, ensuring that the voltages across the multiple shared clamping capacitors are the same, preventing loops through the switching transistors from forming between the multiple shared clamping capacitors. Furthermore, this facilitates a more balanced power distribution among the multiple current-source dual active bridge converter modules in the DC-DC converter, improving the efficiency and stability of the DC-DC converter output.

[0049] The primary-side full-bridge circuit of the current-type dual active bridge converter module includes a first primary-side bridge arm and a second primary-side bridge arm, with an upper bridge arm output terminal and a lower bridge arm output terminal between the first primary-side bridge arm and the second primary-side bridge arm.

[0050] For details, please refer to the following: Figure 2 In the primary-side full-bridge circuit of the first current-type dual active bridge converter module 11, switches S1 and S2 can be connected in series to form the first primary-side bridge arm, and switches S3 and S4 can be connected in series to form the second primary-side bridge arm. The first and second primary-side bridge arms are connected in parallel. Switches S1 and S3 serve as the upper bridge arms of the first and second primary-side bridge arms, respectively, and S2 and S4 serve as the lower bridge arms of the first and second primary-side bridge arms, respectively. Similarly, in the primary-side full-bridge circuit of the second current-type dual active bridge converter module 12, S1' and S2' can be connected in series to form the first primary-side bridge arm, and S3' and S4' can be connected in series to form the second primary-side bridge arm. The first and second primary-side bridge arms are connected in parallel. S1' and S3' constitute the upper bridge arms of the first and second primary-side bridge arms, respectively, and S2' and S4' constitute the lower bridge arms of the first and second primary-side bridge arms, respectively.

[0051] In this embodiment, the output side of the upper arm of the first primary-side bridge arm is connected to the output side of the upper arm of the second primary-side bridge arm to form the upper arm output terminal. The output side of the upper arm in the first and second primary-side bridge arms refers to the side where current flows out after the upper arm is turned on. The output side of the lower arm of the first primary-side bridge arm is connected to the output side of the lower arm of the second primary-side bridge arm to form the lower arm output terminal. The output side of the lower arm in the first and second primary-side bridge arms refers to the side where current is output after the lower arm is turned on. A common clamping capacitor C0 is connected between the upper arm output terminal and the lower arm output terminal. In some embodiments, when there are multiple common clamping capacitors, such as... Figure 3 As shown, common clamping capacitors C0 and C1 are connected in parallel between the output terminals of the upper and lower bridge arms. Alternatively, as... Figure 4 As shown, the common clamping capacitors C0, C1 and C2 are connected in parallel between the upper bridge arm output terminal and the lower bridge arm output terminal.

[0052] In some embodiments, the DC-DC converter includes a controller; the low-voltage side of the first current-mode dual active bridge converter module and the low-voltage side of the second current-mode dual active bridge converter module share the first DC inductor and the second DC inductor.

[0053] Please see Figure 2 The controller can respectively control the upper arm of the first primary-side bridge arm and the lower arm of the second primary-side bridge arm in the first current-type dual active bridge converter module 11 and the second current-type dual active bridge converter module 12 to conduct electrically, so that the positive terminal of the DC source connected to the DC converter 10 and the first DC inductor L are connected to the DC converter 10. dc1 The primary winding of transformer T1 in the first current-type dual active bridge converter module 11, the lower arm of the second primary side bridge arm in the first current-type dual active bridge converter module 11, and the negative terminal of the DC source form a first circuit. Also, the positive terminal of the DC source and the first DC inductor L... dc1 The primary winding of transformer T2 in the second current-type dual active bridge converter module 12, the lower arm of the second primary side bridge arm in the second current-type dual active bridge converter module, and the negative terminal of the DC source form a second circuit. Also, the positive terminal of the DC source and the first DC inductor L... dc1 In the first current-type dual active bridge converter module 11, the upper arm of the first primary side bridge arm and the common clamping capacitor C0 are connected to the negative terminal of the DC source to form a third circuit. Also, the positive terminal of the DC source and the first DC inductor L... dc1 The upper arm of the first primary side bridge arm in the second current-type dual active bridge converter module 12 and the common clamping capacitor C0 are connected to the negative terminal of the DC source to form a fourth circuit.

[0054] In this embodiment, when the upper arm of the first primary-side bridge arm and the lower arm of the second primary-side bridge arm are electrically connected in the first current-type dual active bridge converter module 11 and the second current-type dual active bridge converter module 12, four loops are formed within the DC-DC converter 10: a first loop, a second loop, a third loop, and a fourth loop. The first loop is used to transmit power to the high-voltage side of the first current-type dual active bridge converter module 11. The second loop is used to transmit power to the high-voltage side of the second current-type dual active bridge converter module 12. The third loop connects the primary-side full-bridge circuit of the first current-type dual active bridge converter module 11 to a common clamping capacitor C0, thereby reducing the peak voltage on the low-voltage side of the first current-type dual active bridge converter module 11 through the common clamping capacitor C0. The fourth loop connects the primary-side full-bridge circuit of the second current-type dual active bridge converter module 12 to the common clamping capacitor C0, thereby reducing the peak voltage on the low-voltage side of the second current-type dual active bridge converter module 12 through the common clamping capacitor C0.

[0055] The first current-source dual active bridge converter module 11 and the second current-source dual active bridge converter module 12 will share the first DC inductor L. dc1 The current. Preferably, the first current-type dual active bridge converter module 11 and the second current-type dual active bridge converter module 12 equally bisect the current flowing through the first DC inductor L. dc1 The current.

[0056] Of course, in this embodiment, Figure 2 This example uses a shared clamping capacitor C0 as an example. In actual solutions, the number of shared clamping capacitors is not limited to one; there can be multiple capacitors, such as... Figure 3 or Figure 4 As shown. When there are multiple shared clamping capacitors, they can be combined into a single shared clamping capacitor module and connected as a whole in the third and fourth circuits. Within this shared clamping capacitor module, the multiple shared clamping capacitors are connected in parallel.

[0057] In some embodiments, the controller can respectively control the lower arm of the first primary bridge arm and the upper arm of the second primary bridge arm in the first current-type dual active bridge converter module 11 and the second current-type dual active bridge converter module 12 to be electrically connected, so that the positive terminal of the DC source connected to the DC converter 10 and the second DC inductor L are connected to the DC converter 10. dc2 The primary winding of transformer T1 in the first current-type dual active bridge converter module 11, the lower arm of the first primary side bridge arm in the first current-type dual active bridge converter module 11, and the negative terminal of the DC source form a fifth circuit, and the positive terminal of the DC source and the second DC inductor L... dc2 The primary winding of transformer T2 in the second current-type dual active bridge converter module 12, the lower arm of the first primary side bridge arm in the second current-type dual active bridge converter module 12, and the negative terminal of the DC source form a sixth circuit, and the positive terminal of the DC source and the second DC inductor L... dc2 The upper arm of the second primary side bridge arm in the first current-type dual active bridge converter module 11, the common clamping capacitor C0, and the negative terminal of the DC source form a seventh circuit, and the positive terminal of the DC source and the second DC inductor L... dc2 The upper arm of the second primary side bridge arm in the second current-type dual active bridge converter module 12, along with the common clamping capacitor C0, is connected to the negative terminal of the DC source to form the eighth circuit.

[0058] In this embodiment, when the lower arm of the first primary-side bridge arm and the upper arm of the second primary-side bridge arm are electrically connected in the first current-type dual active bridge converter module 11 and the second current-type dual active bridge converter module 12, four circuits—a fifth circuit, a sixth circuit, a seventh circuit, and an eighth circuit—are formed within the DC-DC converter 10. The fifth circuit is used to transmit power to the secondary-side full-bridge circuit of the first current-type dual active bridge converter module 11. The sixth circuit is used to transmit power to the secondary-side full-bridge circuit of the second current-type dual active bridge converter module 12. The seventh circuit is used to connect the primary-side full-bridge circuit of the first current-type dual active bridge converter module 11 to a common clamping capacitor C0, thereby reducing the peak voltage of the primary-side full-bridge circuit of the first current-type dual active bridge converter module 11 through the common clamping capacitor C0. The eighth circuit is used to connect the primary-side full-bridge circuit of the second current-type dual active bridge converter module 12 to the common clamping capacitor C0, so as to reduce the peak voltage of the primary-side full-bridge circuit of the second current-type dual active bridge converter module 12 through the common clamping capacitor C0.

[0059] The first current-source dual active bridge converter module 11 and the second current-source dual active bridge converter module 12 will share the second DC inductor L. dc1 The current. Preferably, the first current-type dual active bridge converter module 11 and the second current-type dual active bridge converter module 12 equally bisect the current flowing through the second DC inductor L. dc1 The current.

[0060] Of course, in this embodiment, Figure 2 This example uses a shared clamping capacitor C0 as an example. In actual solutions, the number of shared clamping capacitors is not limited to one; there can be multiple capacitors, such as... Figure 3 or Figure 4 As shown. When there are multiple shared clamping capacitors, they can be combined into a single shared clamping capacitor module and connected as a whole in the seventh and eighth circuits. Within this shared clamping capacitor module, the multiple shared clamping capacitors are connected in parallel. Furthermore, the parallel connection of the multiple shared clamping capacitors ensures that they all have the same voltage, preventing the formation of loops between them.

[0061] In some embodiments, the controller controls the switching transistors in the current-mode dual active bridge converter module to achieve the DC-DC conversion function of the DC-DC converter 10. Specifically, the controller can control the on or off time of each switching transistor in the current-mode dual active bridge converter module through a control signal with a certain duty cycle to achieve switching between different loops in the primary-side full-bridge circuit or the secondary-side full-bridge circuit, thereby regulating the output voltage. For example, for the low-voltage side, the controller can control four switching transistors S1, S4, S1', and S2' to alternately conduct with four switching transistors S2, S3, S2', and S3', i.e., the phase difference of the control signal is 180 degrees, so that when four switching transistors S1, S4, S1', and S2' are on, four switching transistors S2, S3, S2', and S3' are off. When four switching transistors S2, S3, S2', and S3' are on, four switching transistors S1, S4, S1', and S2' are off. Thus, in conjunction with the previous embodiments, the first circuit to the fourth circuit, or the fifth circuit to the eighth circuit, can be connected.

[0062] It should be noted that the specific method by which the controller implements control can be through a control signal with a certain duty cycle or other methods. This manual does not limit this, as long as the control logic can be implemented.

[0063] Please see Figure 5 Another embodiment of this specification provides a DC-DC converter 20, including a controller and multiple current-mode dual active bridge converter modules; the multiple current-mode dual active bridge converter modules include a third current-mode dual active bridge converter module 21 and a fourth current-mode dual active bridge converter module 22; the low-voltage side of the third current-mode dual active bridge converter module 21 is connected to a third DC inductor L. dc3 and the fourth DC inductor L dc4 The low-voltage side of the fourth current-type dual active bridge converter module 22 is connected to the fifth DC inductor L. dc5 and the sixth DC inductor L dc6 These multiple current-mode dual active bridge converter modules can share a common clamping capacitor C0.

[0064] Specifically, the primary-side full-bridge circuit of the third current-type dual active bridge converter module 21 includes switches S5, S6, S7, and S8. Switches S5, S6, S7, and S8 are connected to the third DC inductor L in the DC converter 20. dc3 Fourth DC inductor L dc4 This constitutes the buck-boost circuit on the low-voltage side. The secondary-side full-bridge circuit of the third current-type dual active bridge converter module 21 includes: four switching transistors S... 15 S 16 S 17 S 18 .

[0065] The primary-side full-bridge circuit of the fourth current-type dual active bridge converter module 22 includes switches S5', S6', S7', and S8'. Switches S5', S6', S7', and S8' are connected to the fifth DC inductor L in the DC converter 20. dc5 The sixth DC inductor L dc6 This constitutes the buck-boost circuit on the low-voltage side. The secondary-side full-bridge circuit of the fourth current-type dual active bridge converter module 22 includes: four switching transistors S... 15 '、S 16 '、S 17 'and S 18 '.

[0066] In this embodiment, the difference from the DC-DC converter 10 in the previous embodiment is that the DC-DC converter 20 includes four DC inductors. Specifically, the low-voltage side of the third current-type dual active bridge converter module 21 and the fourth current-type dual active bridge converter module 22 each has two DC inductors for forming a buck-boost circuit.

[0067] In this embodiment, V bat V is the voltage of the DC source connected to the low-voltage side of the DC converter 20. bus The DC-DC converter 20 outputs the high-voltage side voltage. In some embodiments, the DC-DC converter 20 may further include a resistor R1 and a switch S. r1 and S r2 The DC-DC converter 20 may also include a low-voltage side soft-start circuit composed of resistor R2, switches K1 and K2. In some embodiments, the DC-DC converter 20 may also include a high-voltage side soft-start circuit composed of resistor R2, switches K1 and K2.

[0068] In some embodiments, the controller controls the upper arm of the first primary bridge arm and the lower arm of the second primary bridge arm in the third current-type dual active bridge converter module 21 to be electrically connected, so that the positive terminal of the DC source connected to the DC converter 20 and the third DC inductor L are connected to the DC converter 20. dc3 The primary winding of transformer T3 in the third current-type dual active bridge converter module 21, the lower arm of the second primary side bridge arm in the third current-type dual active bridge converter module 21, and the negative terminal of the DC source form the ninth circuit, and the positive terminal of the DC source and the third DC inductor L... dc3 The upper arm of the first primary side bridge arm in the third current-type dual active bridge converter module 21, along with the common clamping capacitor C0, is connected to the negative terminal of the DC source to form the tenth circuit.

[0069] In this embodiment, when the upper arm of the first primary-side bridge arm and the lower arm of the second primary-side bridge arm in the third current-type dual active bridge converter module 21 are electrically connected, two circuits, a ninth circuit and a tenth circuit, are formed. The ninth circuit is used to transmit power to the secondary-side full-bridge circuit of the third current-type dual active bridge converter module 21. The tenth circuit is used to connect the primary-side full-bridge circuit of the third current-type dual active bridge converter module 21 to a common clamping capacitor C0, so as to reduce the peak voltage of the primary-side full-bridge circuit of the third current-type dual active bridge converter module 21 through the common clamping capacitor C0.

[0070] Specifically, the controller controls the switching transistors S5 and S8 of the third current-type dual active bridge converter module 21 to turn on. During the power transfer process from the ninth circuit to the secondary full-bridge circuit of the third current-type dual active bridge converter module 21, the common clamping capacitor C0 in the tenth circuit can reduce the voltage spikes in the ninth circuit and reduce the voltage ripple in the ninth circuit.

[0071] In some embodiments, the controller controls the lower arm of the first primary bridge arm and the upper arm of the second primary bridge arm in the third current-type dual active bridge converter module 21 to be electrically connected, so that the positive terminal of the DC source and the fourth DC inductor L are connected. dc4 The primary winding of transformer T3 in the third current-type dual active bridge converter module 21, the lower arm of the first primary side bridge arm in the third current-type dual active bridge converter module 21, and the negative terminal of the DC source form an eleventh circuit, and the positive terminal of the DC source and the third DC inductor L... dc3 The upper arm of the second primary side bridge arm in the third current-type dual active bridge converter module 21, along with the common clamping capacitor C0, is connected to the negative terminal of the DC source to form the twelfth circuit.

[0072] In this embodiment, when the lower arm of the first primary-side bridge arm and the upper arm of the second primary-side bridge arm in the third current-type dual active bridge converter module 21 are electrically connected, two circuits, an eleventh circuit and a twelfth circuit, are formed. The eleventh circuit is used to transfer power to the secondary-side full-bridge circuit of the third current-type dual active bridge converter module 21. The twelfth circuit is used to connect the primary-side full-bridge circuit of the third current-type dual active bridge converter module 21 to a common clamping capacitor C0, so as to reduce the peak voltage of the primary-side full-bridge circuit of the third current-type dual active bridge converter module 21 through the common clamping capacitor C0.

[0073] Specifically, the controller controls the switching transistors S6 and S7 of the third current-type dual active bridge converter module 21 to turn on. During the power transfer from the eleventh circuit to the secondary full-bridge circuit of the third current-type dual active bridge converter module 21, the common clamping capacitor C0 in the twelfth circuit can reduce the voltage spikes in the eleventh circuit and reduce the voltage ripple in the eleventh circuit.

[0074] In some embodiments, the controller controls the upper arm of the first primary side bridge arm and the lower arm of the second primary side bridge arm in the fourth current-type dual active bridge converter module 22 to be electrically connected, so that the positive terminal of the DC source connected to the DC converter 20, the fifth DC inductor Ldc5, the primary winding of the transformer T4 in the fourth current-type dual active bridge converter module 22, the lower arm of the second primary side bridge arm in the fourth current-type dual active bridge converter module 22 to the negative terminal of the DC source form a thirteenth circuit, and the positive terminal of the DC source, the fifth DC inductor Ldc5, the upper arm of the first primary side bridge arm in the fourth current-type dual active bridge converter module 22, the common clamping capacitor C0 to the negative terminal of the DC source form a fourteenth circuit.

[0075] In this embodiment, when the upper arm of the first primary-side bridge arm and the lower arm of the second primary-side bridge arm in the fourth current-type dual active bridge converter module 22 are electrically connected, two loops, the thirteenth and fourteenth loops, are formed. The thirteenth loop is used to transmit power to the secondary-side full-bridge circuit of the fourth current-type dual active bridge converter module 22. The fourteenth loop is used to connect the primary-side full-bridge circuit of the fourth current-type dual active bridge converter module 22 to a common clamping capacitor C0, so as to reduce the peak voltage of the primary-side full-bridge circuit of the fourth current-type dual active bridge converter module 22 through the common clamping capacitor C0.

[0076] Specifically, the controller controls the switching transistors S5' and S8' of the fourth current-type dual active bridge converter module 22 to conduct. During the power transfer from the thirteenth circuit to the secondary full-bridge circuit of the fourth current-type dual active bridge converter module 22, the common clamping capacitor C0 in the fourteenth circuit can reduce the voltage spikes in the thirteenth circuit and reduce the voltage ripple in the fourteenth circuit.

[0077] In some embodiments, the controller controls the lower arm of the first primary side bridge arm and the upper arm of the second primary side bridge arm in the fourth current-type dual active bridge converter module 22 to be electrically connected, so that the positive terminal of the DC source, the sixth DC inductor Ldc6, the primary winding of the transformer T4 in the fourth current-type dual active bridge converter module 22, the lower arm of the first primary side bridge arm in the fourth current-type dual active bridge converter module 22 to the negative terminal of the DC source form a fifteenth circuit, and the positive terminal of the DC source, the sixth DC inductor Ldc6, the upper arm of the second primary side bridge arm in the fourth current-type dual active bridge converter module 22, and the common clamping capacitor C0 to the negative terminal of the DC source form a sixteenth circuit.

[0078] In this embodiment, when the lower arm of the first primary-side bridge arm and the upper arm of the second primary-side bridge arm in the fourth current-type dual active bridge converter module 22 are electrically connected, two loops, the fifteenth and sixteenth loops, are formed. The fifteenth loop is used to transmit power to the secondary-side full-bridge circuit of the fourth current-type dual active bridge converter module 22. The sixteenth loop is used to connect the primary-side full-bridge circuit of the fourth current-type dual active bridge converter module 22 with shared clamping capacitors C3 and C4, so as to reduce the peak voltage of the primary-side full-bridge circuit of the fourth current-type dual active bridge converter module 22 through the shared clamping capacitor C0.

[0079] Specifically, the controller controls the switching transistors S6' and S7' of the fourth current-type dual active bridge converter module 22 to conduct. During the power transfer from the fifteenth circuit to the secondary full-bridge circuit of the fourth current-type dual active bridge converter module 22, the common clamping capacitor C0 in the sixteenth circuit can reduce the voltage spikes in the fifteenth circuit and reduce the voltage ripple in the fifteenth circuit.

[0080] In some embodiments, the controller controls the primary-side full-bridge circuit of the third current-type dual active bridge converter module 21 and the primary-side full-bridge circuit of the fourth current-type dual active bridge converter module 22 to sequentially interleave and form the ninth and tenth circuits, the thirteenth and fourteenth circuits, the eleventh and twelfth circuits, and the fifteenth and sixteenth circuits. Specifically, the controller controls switches S5 and S8 to turn on, forming the ninth and tenth circuits. Then, the controller controls switches S5 and S8 to turn off and switches S5' and S8' to turn on, forming the thirteenth and fourteenth circuits, and there may be a specified phase difference between controlling switches S5' and S8 to turn on. Then, the controller controls switches S5' and S8' to turn off and controls switches S6 and S7 to turn on, forming the tenth and eleventh circuits, and there may be a specified phase difference between controlling switches S6 and S7 to turn on and controlling switches S5' and S8' to turn on. Subsequently, the controller controls switches S6 and S7 to disconnect and switches S6' and S7' to turn on, forming the fifteenth and sixteenth circuits. A specified phase difference can exist between the turn-on of switches S6' and S7 and the turn-on of switches S6 and S7. In this embodiment, the specified phase difference can be 90 degrees. Of course, those skilled in the art can change the specified phase difference according to actual needs.

[0081] In this embodiment, by sequentially interleaving the ninth and tenth circuits, the thirteenth and fourteenth circuits, the eleventh and twelfth circuits, and the fifteenth and sixteenth circuits, the common clamping capacitor C0 is used in four different operating states in an alternating manner. This results in a higher voltage ripple frequency on the common clamping capacitor C0, which helps to stabilize the voltage on the low-voltage side of the third current-type dual active bridge converter module 21 and the low-voltage side of the fourth current-type dual active bridge converter module 22.

[0082] Of course, the aforementioned multiple embodiments, Figure 5 This example uses a shared clamping capacitor C0 as an example. In actual solutions, the number of shared clamping capacitors is not limited to one, such as... Figure 6 or Figure 7 As shown, the number of shared clamping capacitors can also be multiple, among which, Figure 6 The diagram shows two shared clamping capacitors, C0 and C1. Figure 7 Three shared clamping capacitors, C0, C1, and C2, are shown. When there are multiple shared clamping capacitors, they can be combined into a single shared clamping capacitor module and connected as a whole in circuits ten, twelfth, fourteenth, and sixteenth. Within this module, the shared clamping capacitors are connected in parallel. Furthermore, the parallel connection ensures that all shared clamping capacitors have the same voltage, preventing the formation of closed loops between them.

[0083] In some embodiments, the DC-DC converter includes a first output mode and / or a second output mode; wherein, when the DC-DC converter is in the first output mode, the secondary full-bridge circuits of the plurality of current-source dual active bridge converter modules are connected in series to output power externally; when the DC-DC converter is in the second output mode, the secondary full-bridge circuits of the plurality of current-source dual active bridge converter modules are connected in parallel to output power externally.

[0084] The secondary-side full-bridge circuit of a DC-DC converter can have two output modes, which can be flexibly switched according to the output power requirements of the DC-DC converter in actual applications, thus broadening the application scenarios. Specifically, when the DC-DC converter needs to output power to a system with high input power requirements, such as a three-phase system, it can use the first output mode. When the DC-DC converter needs to output power to a system with low input power requirements, such as a single-phase system, it can switch to the second output mode.

[0085] Specifically, with Figure 2Taking the DC-DC converter 10 as an example, the secondary-side full-bridge circuits of the first current-type dual active bridge converter module 11 and the second current-type dual active bridge converter module 12 are connected through an output switching circuit. The output switching circuit includes output switches K3, K4, and K5. When power needs to be output to a three-phase system, the controller can control K4 to close, connecting the output terminals of the secondary-side full-bridge circuits of the first current-type dual active bridge converter module 11 and the second current-type dual active bridge converter module 12 in series, putting the DC-DC converter 10 in the first output mode and achieving a high output voltage. When power needs to be output to a single-phase system, the controller can control K3 and K5 to close, connecting the output terminals of the secondary-side full-bridge circuits of the first current-type dual active bridge converter module 11 and the second current-type dual active bridge converter module 12 in parallel, putting the DC-DC converter 10 in the second output mode and achieving a low voltage output. When the output terminals of the secondary full-bridge circuits of the first current-type dual active bridge converter module 11 and the second current-type dual active bridge converter module 12 are connected in series to output power, the power transmission of a single current-type dual active bridge converter module can be doubled without increasing the stress on the components, so that the DC converter can simultaneously meet the input voltage requirements of single-phase inverters and three-phase inverters.

[0086] Of course, in some embodiments, the DC controller 10 may only have a first output mode, and output switches K3, K4, and K5 may not be required. Figure 3 The K4 position is connected by a wire. In some embodiments, the DC controller 10 may only have a second output mode, and output switches K3, K4, and K5 may not be required. Figure 3 The positions of K3 and K5 are connected by a wire.

[0087] In some embodiments, the controller of the DC-DC converter is configured to receive a mode control signal from a power conversion device connected to the DC-DC converter; the mode control signal includes a first signal or a second signal; when the received mode control signal is the first signal, the controller controls the DC-DC converter to be in a first output mode; the power conversion device suitable for the DC-DC converter in the first output mode is a three-phase power conversion device; or, when the received mode control signal is the second signal, the controller controls the DC-DC converter to be in a second output mode; the power conversion device suitable for the DC-DC converter in the second output mode is a single-phase power conversion device.

[0088] Please see Figure 8A power conversion device is used to connect a DC-DC converter to a load and achieve efficient energy conversion and management. Specifically, the high-voltage side of the DC-DC converter is connected to the input terminal of the power conversion device, and an energy storage system is connected to the low-voltage side of the DC-DC converter. A communication connection can be established between the DC-DC converter and the power conversion device. The load can be a single-phase system or a three-phase system. In some embodiments, the load connected to the power conversion device can also be a photovoltaic system. Specifically, for example, the power conversion device can be a power conversion system (PCS) or an inverter.

[0089] In some embodiments, through data communication between the power conversion device and the DC-DC converter, the power conversion device can send a mode control signal to the DC-DC converter to enable the DC-DC converter to be in a first output mode or a second output mode according to the required power input demand. Specifically, for example, when the load is a three-phase system, the DC-DC converter needs to output high power. At this time, the power conversion device can send a first signal to the DC-DC converter so that the controller of the DC-DC converter can control the DC-DC converter to be in the first output mode upon receiving the first signal.

[0090] In some embodiments, the DC-DC converter integrates an output control program; the controller of the DC-DC converter executes the output control program to ensure that the current output by the secondary full-bridge circuit of the multiple current-type dual active bridge converter modules is equal when the DC-DC converter is in the first output mode; or, the controller of the DC-DC converter executes the output control program to ensure that the voltage output by the secondary full-bridge circuit of the multiple current-type dual active bridge converter modules is equal when the DC-DC converter is in the second output mode.

[0091] In this embodiment, by executing the output control program through the controller, a closed-loop control system with series voltage equalization and parallel current equalization can be formed among the secondary full-bridge circuits of multiple current-type dual active bridge converter modules, further improving the balance of output power.

[0092] Specifically, taking the DC-DC converter in its second output mode as an example, the controller can acquire the voltage and / or current values ​​of the secondary-side full-bridge circuit. Then, aiming for equal output voltages across the secondary-side full-bridge circuits of multiple current-source dual active bridge converter modules, it uses the outward phase shift angle of these modules as a control variable for PI control. Simultaneously, the duty cycle control signals on the low-voltage side of the multiple current-source dual active bridge converter modules maintain a consistent duty cycle. This allows power control through adjusting the outward phase shift angle, achieving an even distribution of output voltages across the secondary-side full-bridge circuits of the multiple current-source dual active bridge converter modules. The DC-DC converter in its first output mode can be controlled based on a similar principle, which will not be elaborated upon here. The above control logic can be integrated into the output control program and executed by the controller.

[0093] It should be noted that the output control program can also use some other control logic. The specific control logic design needs to be combined with the connection method between the secondary full-bridge circuits of multiple current-type dual active bridge converter modules. This manual does not make specific limitations on this. As long as series voltage equalization and parallel current equalization can be achieved between the secondary full-bridge circuits of multiple current-type dual active bridge converter modules.

[0094] This specification also provides a power conversion system, which includes a DC-DC converter as described in any of the foregoing embodiments.

[0095] In some embodiments, the input terminal of the DC-DC converter is used to connect to an energy storage system, and the output terminal of the DC-DC converter is used to connect to a power conversion device.

[0096] This specification also provides a control method for a DC-DC converter, the method comprising: controlling multiple current-type dual active bridge converter modules connected in parallel on the low-voltage side to share a common clamping capacitor during operation.

[0097] The specific functions and effects of each step in the control method of the DC converter can be explained by referring to the foregoing embodiments, and will not be repeated here.

[0098] In some embodiments, the control method for the DC-DC converter is applied to a controller. The controller can implement the functions described in the foregoing embodiments by executing the control method for the DC-DC converter. Specifically, the control method for the controller to control the DC-DC converter can be referred to the foregoing embodiments and will not be repeated here.

[0099] This specification also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the control method of the DC-DC converter in any of the above embodiments.

[0100] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc. can transmit electrical signals or data to each other.

[0101] It is understood that the specific examples in this document are only intended to help those skilled in the art better understand the embodiments of this specification, and are not intended to limit the scope of the invention.

[0102] It is understood that in the various embodiments of this specification, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this specification.

[0103] It is understood that the various embodiments described in this specification can be implemented individually or in combination, and the embodiments in this specification are not limited in this respect.

[0104] Unless otherwise stated, all technical and scientific terms used in the embodiments of this specification have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of this specification. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items. The singular forms "a," "the," and "the" as used in the embodiments of this specification and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0105] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this specification.

[0106] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0107] As should be understood from the several embodiments provided in this specification, the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0108] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0109] The above description is merely a specific embodiment of this specification, but the scope of protection of this invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this specification should be included within the scope of protection of this specification. Therefore, the scope of protection of this invention should be determined by the scope of the claims.

Claims

1. A direct current converter, characterized by Comprise: a plurality of current-mode dual active bridge conversion modules; wherein the current-mode dual active bridge conversion module comprises a primary full-bridge circuit, a transformer and a secondary full-bridge circuit; wherein the low-voltage sides of the plurality of current-mode dual active bridge conversion modules are connected in parallel, and the direct current converter comprises a shared clamping capacitor shared by the plurality of current-mode dual active bridge conversion modules.

2. The dc-dc converter of claim 1, wherein, The primary full-bridge circuit of the current-mode dual active bridge conversion module comprises a first primary bridge arm and a second primary bridge arm, and has an upper bridge arm output end and a lower bridge arm output end between the first primary bridge arm and the second primary bridge arm; wherein the shared clamping capacitor is connected between the upper bridge arm output end and the lower bridge arm output end.

3. The dc-dc converter of claim 2, wherein, The number of shared clamping capacitors is multiple, and the multiple shared clamping capacitors are connected in parallel between the upper bridge arm output end and the lower bridge arm output end.

4. The dc-dc converter of claim 1, wherein, The direct current converter comprises a controller; the primary full-bridge circuit of the current-mode dual active bridge conversion module comprises a first primary bridge arm and a second primary bridge arm; the plurality of current-mode dual active bridge conversion modules comprise a first current-mode dual active bridge conversion module and a second current-mode dual active bridge conversion module; the low-voltage sides of the first current-mode dual active bridge conversion module and the second current-mode dual active bridge conversion module share a first direct current inductor and a second direct current inductor; The controller can respectively control the upper bridge arm of the first primary bridge arm and the lower bridge arm of the second primary bridge arm in the first current-mode dual active bridge conversion module and the second current-mode dual active bridge conversion module to be electrically conductive, so that the positive electrode of the direct current source connected by the direct current converter, the first direct current inductor, the primary winding of the transformer in the first current-mode dual active bridge conversion module, the lower bridge arm of the second primary bridge arm in the first current-mode dual active bridge conversion module to the negative electrode of the direct current source form a first loop, and the positive electrode of the direct current source, the first direct current inductor, the primary winding of the transformer in the second current-mode dual active bridge conversion module, the lower bridge arm of the second primary bridge arm in the second current-mode dual active bridge conversion module to the negative electrode of the direct current source form a second loop, and the positive electrode of the direct current source, the first direct current inductor, the upper bridge arm of the first primary bridge arm in the first current-mode dual active bridge conversion module, the shared clamping capacitor to the negative electrode of the direct current source form a third loop, and the positive electrode of the direct current source, the first direct current inductor, the upper bridge arm of the first primary bridge arm in the second current-mode dual active bridge conversion module, the shared clamping capacitor to the negative electrode of the direct current source form a fourth loop; or, The controller can respectively control the first current-mode dual active bridge conversion module and the second current-mode dual active bridge conversion module, the lower bridge arm of the first primary bridge arm and the upper bridge arm of the second primary bridge arm to be electrically conductive, so that the positive pole of the DC source connected by the DC converter, the second DC inductor, the primary winding of the transformer in the first current-mode dual active bridge conversion module, the lower bridge arm of the first primary bridge arm in the first current-mode dual active bridge conversion module to the negative pole of the DC source form the ninth loop, and the positive pole of the DC source, the second DC inductor, the primary winding of the transformer in the second current-mode dual active bridge conversion module, the lower bridge arm of the first primary bridge arm in the second current-mode dual active bridge conversion module to the negative pole of the DC source form the tenth loop, and the positive pole of the DC source, the second DC inductor, the upper bridge arm of the second primary bridge arm in the first current-mode dual active bridge conversion module, the common clamping capacitor to the negative pole of the DC source form the eleventh loop, and the positive pole of the DC source, the second DC inductor, the upper bridge arm of the second primary bridge arm in the second current-mode dual active bridge conversion module, the common clamping capacitor to the negative pole of the DC source form the twelfth loop.

5. The dc-dc converter of claim 1, wherein, The DC converter comprises a controller; the primary full-bridge circuit of the current-mode dual active bridge conversion module comprises a first primary bridge arm and a second primary bridge arm; the plurality of current-mode dual active bridge conversion modules comprise a third current-mode dual active bridge conversion module and a fourth current-mode dual active bridge conversion module; the low-voltage side of the third current-mode dual active bridge conversion module is connected with a third DC inductor and a fourth DC inductor; the low-voltage side of the fourth current-mode dual active bridge conversion module is connected with a fifth DC inductor and a sixth DC inductor; The controller controls the upper bridge arm of the first primary bridge arm and the lower bridge arm of the second primary bridge arm in the third current-mode dual active bridge conversion module to be electrically conductive, so that the positive pole of the DC source connected by the DC converter, the third DC inductor, the primary winding of the transformer in the third current-mode dual active bridge conversion module, the lower bridge arm of the second primary bridge arm in the first current-mode dual active bridge conversion module to the negative pole of the DC source form the ninth loop, and the positive pole of the DC source, the third DC inductor, the upper bridge arm of the first primary bridge arm in the third current-mode dual active bridge conversion module, the common clamping capacitor to the negative pole of the DC source form the tenth loop; Or, the controller controls the lower bridge arm of the first primary bridge arm and the upper bridge arm of the second primary bridge arm in the third current-mode dual active bridge conversion module to be electrically conductive, so that the positive pole of the DC source, the fourth DC inductor, the primary winding of the transformer in the third current-mode dual active bridge conversion module, the lower bridge arm of the first primary bridge arm in the third current-mode dual active bridge conversion module to the negative pole of the DC source form an eleventh loop, and the positive pole of the DC source, the third DC inductor, the upper bridge arm of the second primary bridge arm in the third current-mode dual active bridge conversion module, the common clamping capacitor to the negative pole of the DC source form a twelfth loop. Or, the controller controls the upper bridge arm of the first primary bridge arm and the lower bridge arm of the second primary bridge arm in the fourth current-mode dual active bridge conversion module to be electrically conductive, so that the positive pole of the DC source connected to the DC converter, the fifth DC inductor, the primary winding of the transformer in the fourth current-mode dual active bridge conversion module, the lower bridge arm of the second primary bridge arm in the fourth current-mode dual active bridge conversion module to the negative pole of the DC source form a thirteenth loop, and the positive pole of the DC source, the fifth DC inductor, the upper bridge arm of the first primary bridge arm in the fourth current-mode dual active bridge conversion module, the common clamping capacitor to the negative pole of the DC source form a fourteenth loop. Or, the controller controls the lower bridge arm of the first primary bridge arm and the upper bridge arm of the second primary bridge arm in the fourth current-mode dual active bridge conversion module to be electrically conductive, so that the positive pole of the DC source, the sixth DC inductor, the primary winding of the transformer in the fourth current-mode dual active bridge conversion module, the lower bridge arm of the first primary bridge arm in the fourth current-mode dual active bridge conversion module to the negative pole of the DC source form a fifteenth loop, and the positive pole of the DC source, the sixth DC inductor, the upper bridge arm of the second primary bridge arm in the fourth current-mode dual active bridge conversion module, the common clamping capacitor to the negative pole of the DC source form a sixteenth loop.

6. The dc-dc converter of claim 1, wherein, The number of common clamping capacitors is multiple, and the number of common clamping capacitors is greater than or equal to the number of current-mode dual active bridge conversion modules in the plurality of current-mode dual active bridge conversion modules.

7. The dc-dc converter of claim 1, wherein, The DC converter comprises a first output mode and / or a second output mode; when the DC converter is in the first output mode, the secondary side full bridge circuits of the plurality of current-mode dual active bridge conversion modules are connected in series to output power externally; when the DC converter is in the second output mode, the secondary side full bridge circuits of the plurality of current-mode dual active bridge conversion modules are connected in parallel to output power externally.

8. The dc to dc converter of claim 7, wherein, The controller of the DC converter is used to receive a mode control signal sent by a power conversion device connected to the DC converter; the mode control signal comprises a first signal or a second signal. The controller controls the DC converter to be in the first output mode when the received mode control signal is the first signal; the power conversion device to which the DC converter in the first output mode is applicable is a three-phase power conversion device; Or, The controller controls the DC converter to be in the second output mode when the received mode control signal is the second signal; the power conversion device to which the DC converter in the second output mode is applicable is a single-phase power conversion device.

9. The dc to dc converter of claim 7, wherein, The DC converter integrates an output control program; the controller of the DC converter realizes, by executing the output control program, that the currents output by the secondary full-bridge circuits of the plurality of current-type dual active bridge conversion modules are equal when the DC converter is in the first output mode; or the controller of the DC converter realizes, by executing the output control program, that the voltages output by the secondary full-bridge circuits of the plurality of current-type dual active bridge conversion modules are equal when the DC converter is in the second output mode.

10. A power conversion system, characterized by, The power conversion system comprises the DC converter according to any one of claims 1 to 9.

11. A control method of a direct current converter, characterized by, The method comprises: Controlling a plurality of current-type dual active bridge conversion modules in parallel on the low-voltage side to commonly use a shared clamping capacitor during operation.

12. The method of claim 11, wherein, The primary full-bridge circuit of the current-type dual active bridge conversion module comprises a first primary bridge arm and a second primary bridge arm; the plurality of current-type dual active bridge conversion modules comprise a first current-type dual active bridge conversion module and a second current-type dual active bridge conversion module; the low-voltage side of the first current-type dual active bridge conversion module and the low-voltage side of the second current-type dual active bridge conversion module share a first DC inductor and a second DC inductor; Controlling a plurality of current-type dual active bridge conversion modules in parallel on the low-voltage side to commonly use a shared clamping capacitor during operation comprises: Controlling a plurality of current-type dual active bridge conversion modules in parallel on the low-voltage side to commonly use a shared clamping capacitor during operation comprises: The first primary bridge arm and the second primary bridge arm in the first current-mode dual active bridge conversion module and the second current-mode dual active bridge conversion module are respectively controlled to be electrically conductive, so that the positive electrode of the DC source connected by the DC converter, the first DC inductor, the primary winding of the transformer in the first current-mode dual active bridge conversion module, the lower bridge arm of the second primary bridge arm in the first current-mode dual active bridge conversion module, and the negative electrode of the DC source form a first loop, and the positive electrode of the DC source, the first DC inductor, the primary winding of the transformer in the second current-mode dual active bridge conversion module, the lower bridge arm of the second primary bridge arm in the second current-mode dual active bridge conversion module, and the negative electrode of the DC source form a second loop, and the positive electrode of the DC source, the first DC inductor, the upper bridge arm of the first primary bridge arm in the first current-mode dual active bridge conversion module, and the common clamping capacitor form a third loop, and the positive electrode of the DC source, the first DC inductor, the upper bridge arm of the first primary bridge arm in the second current-mode dual active bridge conversion module, and the common clamping capacitor form a fourth loop. Alternatively, The first primary bridge arm and the second primary bridge arm in the first current-mode dual active bridge conversion module and the second current-mode dual active bridge conversion module are respectively controlled to be electrically conductive, so that the positive electrode of the DC source connected by the DC converter, the second DC inductor, the primary winding of the transformer in the first current-mode dual active bridge conversion module, the lower bridge arm of the first primary bridge arm in the first current-mode dual active bridge conversion module, and the negative electrode of the DC source form a fifth loop, and the positive electrode of the DC source, the second DC inductor, the primary winding of the transformer in the second current-mode dual active bridge conversion module, the lower bridge arm of the first primary bridge arm in the second current-mode dual active bridge conversion module, and the negative electrode of the DC source form a sixth loop, and the positive electrode of the DC source, the first DC inductor, the upper bridge arm of the second primary bridge arm in the first current-mode dual active bridge conversion module, and the common clamping capacitor form a seventh loop, and the positive electrode of the DC source, the second DC inductor, the upper bridge arm of the second primary bridge arm in the second current-mode dual active bridge conversion module, and the common clamping capacitor form an eighth loop.

13. The method of claim 11, wherein, The primary full-bridge circuit of the current-mode dual active bridge conversion module includes a first primary bridge arm and a second primary bridge arm; the plurality of current-mode dual active bridge conversion modules include a third current-mode dual active bridge conversion module and a fourth current-mode dual active bridge conversion module; the low-voltage side of the third current-mode dual active bridge conversion module is connected with a third DC inductor and a fourth DC inductor; and the low-voltage side of the fourth current-mode dual active bridge conversion module is connected with a fifth DC inductor and a sixth DC inductor. The step of controlling the plurality of current-mode dual active bridge conversion modules in parallel on the low-voltage side to jointly use the shared clamping capacitor during operation includes: controlling the upper bridge arm of the first primary bridge arm and the lower bridge arm of the second primary bridge arm in the first current-mode dual active bridge conversion module to be electrically conductive, so that the positive electrode of the direct current source connected by the direct current converter, the third direct current inductor, the primary winding of the transformer in the first current-mode dual active bridge conversion module, the lower bridge arm of the second primary bridge arm in the first current-mode dual active bridge conversion module to the negative electrode of the direct current source, form the ninth loop, and the positive electrode of the direct current source, the third direct current inductor, the upper bridge arm of the first primary bridge arm in the first current-mode dual active bridge conversion module, and the shared clamping capacitor to the negative electrode of the direct current source, form the tenth loop; Alternatively, controlling the lower bridge arm of the first primary bridge arm and the upper bridge arm of the second primary bridge arm in the first current-mode dual active bridge conversion module to be electrically conductive, so that the positive electrode of the direct current source, the fourth direct current inductor, the primary winding of the transformer in the first current-mode dual active bridge conversion module, the lower bridge arm of the first primary bridge arm in the first current-mode dual active bridge conversion module to the negative electrode of the direct current source, form the ninth loop, and the positive electrode of the direct current source, the third direct current inductor, the upper bridge arm of the second primary bridge arm in the first current-mode dual active bridge conversion module, and the shared clamping capacitor to the negative electrode of the direct current source, form the tenth loop; Alternatively, controlling the upper bridge arm of the first primary bridge arm and the lower bridge arm of the second primary bridge arm in the second current-mode dual active bridge conversion module to be electrically conductive, so that the positive electrode of the direct current source connected by the direct current converter, the fifth direct current inductor, the primary winding of the transformer in the second current-mode dual active bridge conversion module, the lower bridge arm of the second primary bridge arm in the second current-mode dual active bridge conversion module to the negative electrode of the direct current source, form the eleventh loop, and the positive electrode of the direct current source, the fifth direct current inductor, the upper bridge arm of the first primary bridge arm in the second current-mode dual active bridge conversion module, and the shared clamping capacitor to the negative electrode of the direct current source, form the twelfth loop; Alternatively, controlling the lower bridge arm of the first primary bridge arm and the upper bridge arm of the second primary bridge arm in the second current-mode dual active bridge conversion module to be electrically conductive, so that the positive electrode of the direct current source, the sixth direct current inductor, the primary winding of the transformer in the second current-mode dual active bridge conversion module, the lower bridge arm of the first primary bridge arm in the second current-mode dual active bridge conversion module to the negative electrode of the direct current source, form the thirteenth loop, and the positive electrode of the direct current source, the sixth direct current inductor, the upper bridge arm of the second primary bridge arm in the second current-mode dual active bridge conversion module, and the shared clamping capacitor to the negative electrode of the direct current source, form the fourteenth loop.

14. The method of claim 11, wherein, The method further includes: The control method comprises the following steps:

15. The method of claim 14, wherein, controlling the DC converter to be in a first output mode or a second output mode; wherein, when the DC converter is in the first output mode, the multiple current-type dual active bridge conversion modules are connected in series between the secondary full-bridge circuits to output power; when the DC converter is in the second output mode, the multiple current-type dual active bridge conversion modules are connected in parallel between the secondary full-bridge circuits to output power. The step of controlling the DC converter to be in the first output mode or the second output mode comprises: receiving a mode control signal sent by a power conversion device to which the DC converter is connected; wherein, the mode control signal comprises a first signal or a second signal; when the received mode control signal is the first signal, controlling the DC converter to be in the first output mode; wherein, the power conversion device to which the DC converter is connected in the first output mode is a three-phase power conversion device; or, when the received mode control signal is the second signal, controlling the DC converter to be in the second output mode; wherein, the power conversion device to which the DC converter is connected in the second output mode is a single-phase power conversion device.

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