Dual-active-bridge converter and power supply apparatus

Abstract

The present disclosure relates to a dual-active-bridge converter and a power supply apparatus. The dual-active-bridge converter comprises multiple phases of transformers that are arranged and assembled in sequence, wherein a primary winding and a secondary winding in each phase of transformer are respectively wound on two winding post magnetic cores, the two winding post magnetic cores are positioned opposite each other, the two winding post magnetic cores are connected by means of two non-winding-post magnetic cores, and every two adjacent phases of transformers share a single non-winding-post magnetic core.

Description

A dual active bridge converter and power supply device

[0001] Cross-reference to related applications

[0002] This disclosure claims priority to Chinese Patent Application No. 2024113934605, filed on October 8, 2024, entitled “A Dual Active Bridge Converter, Bidirectional DC-DC Converter Module and Power Supply Device”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of high-power power electronic magnetic integration technology, and particularly to a dual active bridge converter and power supply device. Background Technology

[0004] With the increasing demand for electricity, bidirectional DC-DC converters are playing an increasingly important role in modern electrical engineering due to their simple structure, high efficiency, and bidirectional energy flow. Magnetic components are key devices in bidirectional DC-DC converters, enabling the conversion between electrical and magnetic energy to ensure the converter's reliability and safety. However, they are characterized by their heavy weight and large size. Statistics show that the weight and volume of magnetic components typically account for 20%-30% of the total weight and volume of the converter. This restricts the development of bidirectional DC-DC converters towards lighter weight, smaller size, higher power density, and higher efficiency.

[0005] In some cases, N inductors and N transformers are required for an N-phase dual active bridge converter. If a discrete magnetic component design is adopted, 2*N magnetic components are required, which seriously violates the original intention of high efficiency and high power density.

[0006] Summary of the Invention

[0007] This disclosure provides a dual active bridge converter and a power supply device to solve the problems of heavy and bulky magnetic components in multiphase dual active bridge converters.

[0008] In a first aspect, this disclosure provides a dual active bridge converter, comprising multiphase transformers arranged sequentially. Each phase transformer includes a first wound column core, a second wound column core, a first unwound column core, a second unwound column core, a primary winding, and a secondary winding. The first wound column core, the first unwound column core, the second wound column core, and the second unwound column core in each phase transformer are connected end-to-end, and the first wound column core and the second wound column core are positioned opposite each other. In two adjacent transformers, the first unwound column core of the latter transformer and the second unwound column core of the former transformer are the same core. The primary winding of each phase transformer is wound on the first wound column core of that phase transformer. The secondary winding of each phase transformer is wound on the second wound column core of that phase transformer.

[0009] In one exemplary embodiment, transformers of adjacent phases share a single non-wound column core.

[0010] In one exemplary embodiment, the primary winding and secondary winding of the same phase transformer are wound in the same direction.

[0011] In one exemplary embodiment, an air gap exists inside both the first and second winding cores of each phase transformer.

[0012] In one exemplary embodiment, the primary and secondary windings of all phase transformers are wound in the same direction.

[0013] In an exemplary embodiment, the first wound column core, the second wound column core, the first unwound column core, and the second unwound column core in each phase transformer are all strip cores.

[0014] In an exemplary embodiment, the first wound column core, the first unwound column core, the second wound column core, and the second unwound column core in each phase transformer are connected end to end to form a rectangular structure.

[0015] In one exemplary embodiment, the materials used for the primary winding and the secondary winding include at least one of copper foil, copper wire, aluminum wire, and paper insulation tape.

[0016] In an exemplary embodiment, the first wound post core, the second wound post core, the first unwound post core, and the second unwound post core are all made of ferrite magnetic material.

[0017] In a second aspect, this disclosure provides a power supply device, including a power input terminal, a power supply terminal, a rectifier, and a dual active bridge converter as described in the first aspect. The input terminal of the rectifier is connected to the power input terminal. The output terminal of the rectifier is connected to the first DC side of the dual active bridge converter. The rectifier is used to rectify the AC voltage provided at the power input terminal into a DC voltage to provide the DC voltage to the first DC side of the dual active bridge converter. The second DC side of the dual active bridge converter is connected to the power supply terminal. The dual active bridge converter is used to convert the received DC voltage into a target voltage and provide the converted target voltage to the power supply terminal.

[0018] In one exemplary embodiment, the power supply device further includes an energy storage module. The charging terminal of the energy storage module is connected to the output terminal of the rectifier. The power supply terminal of the energy storage module is connected to the first DC side of the dual active bridge converter. The energy storage module is configured to receive DC voltage from the rectifier for charging when the stored energy value is greater than a preset stored energy limit, and to stop receiving DC voltage from the rectifier and supply DC voltage to the dual active bridge converter when the stored energy value is less than or equal to the preset stored energy limit. Attached Figure Description

[0019] The present disclosure will be described in more detail below based on embodiments and with reference to the accompanying drawings:

[0020] Figure 1 is a schematic diagram of a dual active bridge converter provided in an embodiment of this disclosure.

[0021] Figure 2 is a side view of a dual active bridge converter provided in an embodiment of this disclosure.

[0022] Figure 3 is a top view of a dual active bridge converter provided in an embodiment of this disclosure.

[0023] Figure 4 is a schematic diagram of a dual active bridge converter provided in an embodiment of this disclosure.

[0024] Figure 5a is an analytical diagram of the first phase transformer of a dual active bridge converter provided in an embodiment of this disclosure.

[0025] Figure 5b is a magnetic field strength distribution diagram within the core window of the first phase transformer of a dual active bridge converter provided in an embodiment of this disclosure.

[0026] Figure 6 is a schematic diagram of the equivalent magnetic circuit of a dual active bridge converter provided in an embodiment of this disclosure.

[0027] In the accompanying drawings, the same parts are referred to by the same reference numerals, and the drawings are not drawn to scale. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solutions of this disclosure, and to fully understand and implement the process of how this disclosure applies technical means to solve technical problems and achieve corresponding technical effects, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this disclosure, not all embodiments. The embodiments of this disclosure and the various features within them can be combined with each other without conflict, and the resulting technical solutions are all within the protection scope of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort should fall within the protection scope of this disclosure.

[0029] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this disclosure described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0030] Example

[0031] This disclosure provides a dual active bridge converter, comprising multiphase transformers arranged sequentially. Each phase transformer includes a first wound column core, a second wound column core, a first unwound column core, a second unwound column core, a primary winding, and a secondary winding. The first wound column core, the first unwound column core, the second wound column core, and the second unwound column core in each phase transformer are connected end-to-end, and the first wound column core and the second wound column core are positioned opposite each other. In two adjacent transformers, the first unwound column core of the latter transformer and the second unwound column core of the former transformer are the same core. The primary winding of each phase transformer is wound on the first wound column core of that phase transformer. The secondary winding of each phase transformer is wound on the second wound column core of that phase transformer.

[0032] Figure 4 is a schematic diagram of a dual active bridge converter provided in an embodiment of this disclosure. As shown in Figure 4, this disclosure reduces the coupling between the primary and secondary windings by having adjacent transformers share the same non-wound column core, and by separately winding the primary and secondary windings of each phase transformer onto different wound column cores. This increases the leakage inductance of the transformer, thereby allowing the leakage inductance of the transformer to replace the energy storage inductor, which reduces the size of the inductor core and significantly reduces the volume of the magnetic components. Furthermore, by using the transformer leakage inductance to replace the energy storage inductor, the number of inductor windings and inductor cores is reduced, which helps to reduce the winding losses and core losses of the converter.

[0033] In an exemplary embodiment, the first wound post core, the second wound post core, the first unwound post core, and the second unwound post core are all made of ferrite magnetic material.

[0034] In one exemplary embodiment, the materials used for the primary winding and the secondary winding include at least one of copper foil, copper wire, aluminum wire, and paper insulation tape.

[0035] In an exemplary embodiment, FIG1 is a schematic structural diagram of a dual active bridge converter provided in an embodiment of the present disclosure. FIG2 is a side view of a dual active bridge converter provided in an embodiment of the present disclosure. FIG3 is a top view of a dual active bridge converter provided in an embodiment of the present disclosure.

[0036] As shown in Figures 1, 2, and 3, the dual active bridge converter includes N-phase transformers arranged sequentially, where N is a positive integer greater than 1. The first wound column core, second wound column core, first unwound column core, and second unwound column core in each phase transformer are all strip cores. The first wound column core, first unwound column core, second wound column core, and second unwound column core in each phase transformer are connected end-to-end to form a rectangular structure.

[0037] In the following text, the numbers after the core number represent the core number. For example, the first winding post core 1 represents the first winding post core, the first winding post core 2*N-1 represents the second winding post core, the second winding post core 2 represents the second winding post core, the second winding post core 2*N represents the second winding post core, the first non-winding post core 2*N+1 represents the second non-winding post core, and the second non-winding post core 2*N+2 represents the second non-winding post core.

[0038] The first-phase transformer includes a first wound column core 1, a second wound column core 2, a first unwound column core (i.e., a yoke) 2*N+1, a second unwound column core 2*N+2, a primary winding Np1, and a secondary winding Ns1. The second-phase transformer includes a first wound column core 3, a second wound column core 4, a first unwound column core 2*N+2, a second unwound column core 2*N+3, a primary winding Np2, and a secondary winding Ns2. The Nth-phase transformer includes a first wound column core 2*N-1, a second wound column core 2*N, a first unwound column core 3*N, a second unwound column core 3*N+1, a primary winding Npn, and a secondary winding Nsn. Where n = 1, 2, 3, ..., N.

[0039] The primary winding Np1 of the first-phase transformer is wound on the first winding core 1. The secondary winding Ns1 of the first-phase transformer is wound on the second winding core 2. The primary winding Np2 of the second-phase transformer is wound on the first winding core 3. The secondary winding Ns2 of the first-phase transformer is wound on the second winding core 4. The primary winding Npn of the Nth-phase transformer is wound on the first winding core 2*N-1. The secondary winding Nsn of the first-phase transformer is wound on the second winding core 2*N.

[0040] In one exemplary embodiment, the primary winding and secondary winding of the same phase transformer are wound in the same direction.

[0041] In one exemplary embodiment, all windings (including primary and secondary windings) of the N-phase transformer have the same winding direction. The current phases between the windings differ sequentially by 360° / n.

[0042] For example, as shown in Figure 1, the same-name terminal of the primary winding Np1 of the first-phase transformer is A1. The opposite-name terminal of the primary winding Np1 of the first-phase transformer is B1. The same-name terminal of the secondary winding Ns1 of the first-phase transformer is C1. The opposite-name terminal of the secondary winding Ns1 of the first-phase transformer is D1. The same-name terminal of the primary winding Np2 of the second-phase transformer is A2. The opposite-name terminal of the primary winding Np2 of the second-phase transformer is B2. The same-name terminal of the secondary winding Ns2 of the second-phase transformer is C2. The opposite-name terminal of the secondary winding Ns2 of the second-phase transformer is D2. The same-name terminal of the primary winding Npn of the Nth-phase transformer is An. The opposite-name terminal of the primary winding Npn of the Nth-phase transformer is Bn. The same-name terminal of the secondary winding Nsn of the Nth-phase transformer is Cn. The opposite-name terminal of the secondary winding Nsn of the Nth-phase transformer is Dn. In this context, "same-name terminal" refers to the current input terminal, and "different-name terminal" refers to the current output terminal. That is, in a transformer of the same phase, the primary and secondary windings have the same winding direction, and in an N-phase transformer, all windings have the same winding direction.

[0043] In an exemplary embodiment, air gaps exist inside both the first and second winding cores of each phase transformer. As shown in Figure 1, air gaps exist inside both the first winding core 1 and the second winding core 2 of the first phase transformer. Air gaps exist inside both the first winding core 3 and the second winding core 4 of the second phase transformer. Air gaps exist inside both the first winding core 2*N-1 and the second winding core 2*N of the Nth phase transformer. Therefore, the entire N-phase transformer has 2*N air gaps.

[0044] Figure 5a is an analytical diagram of the first-phase transformer of a dual active bridge converter provided in an embodiment of this disclosure. Figure 5b is a magnetic field intensity distribution diagram within the core window of the first-phase transformer of a dual active bridge converter provided in an embodiment of this disclosure. Figure 6 is a schematic diagram of the equivalent magnetic circuit of a dual active bridge converter provided in an embodiment of this disclosure.

[0045] As shown in Figures 5a and 5b, the analysis focuses on one phase of an N-phase transformer. The dashed box in Figure 5a represents the loop. According to Ampere's circuital law: Hl = NI (1)

[0046] Where H is the magnetic field strength, l is the magnetic circuit length, N is the number of coil turns, and I is the current.

[0047] According to Ampere's circuital law, the electric field distribution within the core window can be calculated, and thus the expression for the magnetic field energy can be derived. Here, the expression for the leakage magnetic field energy of the primary winding is:

[0048] The expression for the leakage magnetic field energy of the secondary winding is:

[0049] The expression for the leakage magnetic field energy between the primary and secondary windings is:

[0050] l Np This represents the average winding length of the primary winding in the depth direction. air This represents the average length of the primary and secondary side spacing towards the depth direction. Ns denoted as , where is the average winding length of the secondary winding in the depth direction. The height of the core window occupied by the secondary winding is 'a'. The height of the core window occupied by the primary winding is 'c'. The distance between the primary and secondary windings is 'b'. The width of the core window is 'lw'. 'μ0' is the air permeability. 'Np' is the number of turns in the primary winding. 'Ip' is the current in the primary winding. 'Ns' is the number of turns in the secondary winding. 'Is' is the current in the secondary winding.

[0051] Leakage magnetic field energy W in the core window m For: W m =W p +W s +Wair (5)

[0052] Due to the leakage magnetic field energy W in the core window m Equal to leakage energy W lk :

[0053] Find the leakage inductance L k The expression is:

[0054] As shown in Expression 7 and Figure 5b, when the primary and secondary windings of the same phase transformer are wound on different winding column cores, the magnetic field strength is greatest between the primary and secondary windings. By increasing the distance between the primary and secondary windings, the magnetic energy of the distance between them can be increased, thereby increasing the leakage inductance stored in the air. This allows the leakage inductance of the transformer to replace the energy storage inductor. As shown in Figure 6, the primary and secondary windings of the N-phase transformer are wound in the same direction. According to the right-hand screw rule, the winding direction of the magnetic flux is determined to be the same. The magnetic flux within the same phase transformer cancels each other out, and the magnetic flux between phases flows to the low reluctance (i.e., the winding column reluctance Rm2), forming a loop and achieving decoupling. Thus, the N-phase transformer and N inductors achieve magnetic integration.

[0055] As shown in Figure 6, Rm1 is the reluctance of the side column, Rm2 is the reluctance of the winding column, and Rm3 is the reluctance of the decoupling column. Φ1 is the first-phase flux, Φ2 is the second-phase flux, Φ3 is the third-phase flux, and ΦN is the Nth-phase flux. Decoupling between phases is achieved through air gaps on the winding columns, resulting in high reluctance; the side columns (non-winding columns) have no air gaps, resulting in low reluctance. The flux generated by the primary winding Np1 will not flow through the primary winding Np2, secondary winding Ns2, primary winding Np3, secondary winding Ns3, ..., primary winding Npn, secondary winding Nsn. Similarly, the flux generated by the secondary winding Ns1 will not flow through the primary winding Np2, secondary winding Ns2, primary winding Np3, secondary winding Ns3, ..., primary winding Npn, secondary winding Nsn. By analogy, decoupling is achieved between phases.

[0056] In one embodiment, this disclosure provides a power supply device including a power input terminal, a power supply terminal, a rectifier, and a dual active bridge converter as described above. The input terminal of the rectifier is connected to the power input terminal. The output terminal of the rectifier is connected to the first DC side of the dual active bridge converter. The rectifier is used to rectify the AC voltage provided at the power input terminal into a DC voltage to provide the DC voltage to the first DC side of the dual active bridge converter. The second DC side of the dual active bridge converter is connected to the power supply terminal. The dual active bridge converter is used to convert the received DC voltage into a target voltage and provide the converted target voltage to the power supply terminal.

[0057] In one exemplary embodiment, the power supply device further includes an energy storage module. The charging terminal of the energy storage module is connected to the output terminal of the rectifier. The power supply terminal of the energy storage module is connected to the first DC side of the dual active bridge converter. The energy storage module is configured to receive DC voltage from the rectifier for charging when the stored energy value is greater than a preset stored energy limit, and to stop receiving DC voltage from the rectifier and supply DC voltage to the dual active bridge converter when the stored energy value is less than or equal to the preset stored energy limit.

[0058] The dual active bridge converter provided in this embodiment shares the same non-wound column core between adjacent transformers and winds the primary and secondary windings of each phase transformer separately on different wound column cores. This reduces the coupling between the primary and secondary windings, increases the transformer's leakage inductance, and allows the leakage inductance to replace the energy storage inductor, thereby reducing the inductor core size and significantly decreasing the volume and weight of the magnetic components. Furthermore, using the transformer's leakage inductance to replace the energy storage inductor also reduces the number of inductor windings and the inductor core, which helps reduce winding and core losses in the converter. Moreover, during transformer winding, the primary and secondary windings are wound in the same direction, resulting in a canceling effect of magnetic flux within the same phase transformer. Specifically, at the center column of the two non-wound column cores, the phase-to-phase magnetic flux cancels out. Therefore, the N-phase transformer effectively achieves decoupling.

[0059] While the embodiments disclosed herein are as described above, the foregoing content is merely for the purpose of facilitating understanding of this disclosure and is not intended to limit this disclosure. Any person skilled in the art to which this disclosure pertains may make any modifications and changes in form and detail of the implementation without departing from the spirit and scope of this disclosure; however, the scope of patent protection of this disclosure shall still be determined by the scope defined in the appended claims.

Claims

1. A dual active bridge converter, wherein, It includes a multiphase transformer arranged in sequence, each phase transformer including a first wound column core, a second wound column core, a first unwound column core, a second unwound column core, a primary winding, and a secondary winding; In each phase transformer, the first wound column core, the first unwound column core, the second wound column core, and the second unwound column core are connected end to end, and the positions of the first wound column core and the second wound column core are opposite. In two adjacent transformers, the first unwound column core of the latter transformer and the second unwound column core of the former transformer are the same core. The primary winding of each phase transformer is wound on the first wound column core of the phase transformer, and the secondary winding of each phase transformer is wound on the second wound column core of the phase transformer.

2. The dual active bridge converter according to claim 1, wherein, In a transformer of the same phase, the primary winding and the secondary winding are wound in the same direction.

3. The dual active bridge converter according to claim 1, wherein, There is an air gap inside the first and second winding cores of each phase transformer.

4. The dual active bridge converter according to claim 2, wherein, In all phase transformers, the primary and secondary windings are wound in the same direction.

5. The dual active bridge converter according to claim 1, wherein, The first wound column core, the second wound column core, the first unwound column core, and the second unwound column core in each phase of the transformer are all strip cores.

6. The dual active bridge converter according to claim 5, wherein, The first wound column core, the first unwound column core, the second wound column core, and the second unwound column core in each phase transformer are connected end to end to form a rectangular structure.

7. The dual active bridge converter according to claim 1, wherein, The materials used for the primary winding and the secondary winding include at least one of copper foil, copper wire, aluminum wire, and paper insulation tape.

8. The dual active bridge converter according to claim 1, wherein, The first wound post core, the second wound post core, the first unwound post core, and the second unwound post core are all made of ferrite magnetic material.

9. A power supply device, wherein, Includes a power input terminal, a power supply terminal, a rectifier, and a dual active bridge converter as described in any one of claims 1 to 8; The input terminal of the rectifier is connected to the power input terminal, and the output terminal of the rectifier is connected to the first DC side of the dual active bridge converter; the rectifier is used to rectify the AC voltage provided by the power input terminal into a DC voltage, so as to provide a DC voltage to the first DC side of the dual active bridge converter; The second DC side of the dual active bridge converter is connected to the power supply terminal. The dual active bridge converter is used to convert the received DC voltage into a target voltage and provide the converted target voltage to the power supply terminal.

10. The power supply device according to claim 9, wherein, It further includes an energy storage module, the charging terminal of which is connected to the output terminal of the rectifier, and the power supply terminal of which is connected to the first DC side of the dual active bridge converter. The energy storage module is used to receive DC voltage from the rectifier for charging when the stored energy value is greater than the preset stored energy limit value, and is also used to stop receiving DC voltage from the rectifier and provide DC voltage to the dual active bridge converter when the stored energy value is less than or equal to the preset stored energy limit value.

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