Compact direct current transformer structure

Abstract

The invention discloses a compact direct-current transformer structure, and belongs to the technical field of direct-current power transmission. The direct-current transformer structure comprises an oil-immersed transformer, a low-voltage part and a high-voltage part, the high-voltage part is supported above the low-voltage part through a plurality of insulator assemblies, and the oil-immersed transformer is arranged on one side of the low-voltage part; an external incoming line inputs a current to a power module of a low-voltage part for inversion, the inverted current is subjected to current sharing through symmetrical copper bar current sharing structures on two sides of the power module, the current is input to an oil-immersed transformer for boosting, and the boosted current is input to a high-voltage diode valve string of a high-voltage part for series boosting. The series boosted current is output through a high-voltage part outgoing line; through the symmetrical copper bar current equalizing structure, the current of the single conductor is reduced, the large current is effectively inhibited, the space in the height direction of the container is effectively utilized, the overall size can be reduced, the occupied area is reduced, and field installation and arrangement are facilitated.

Description

A compact DC transformer structure Technical Field

[0001] This invention relates to the field of DC power transmission technology, and more particularly to a compact DC transformer structure. Background Technology

[0002] With the expansion of new energy grid connection and the development of high voltage DC transmission projects towards higher voltage levels, DC transformers, as the core equipment for AC / DC energy conversion, have seen their space efficiency and life-cycle cost become key indicators restricting the economic efficiency of the system.

[0003] Traditional DC transformers employ a planar layout, with all power components, such as IGBT modules, resonant capacitors, and heat sinks, arranged linearly in the horizontal direction. Due to the flat installation structure, the vertical utilization of the equipment is insufficient, resulting in a larger footprint compared to a three-dimensional layout for the same power rating. This directly increases the cost of containerized construction and the amount of associated civil engineering work. Because the overall dimensions exceed road transport limits, the equipment must be transported in parts to the site for multi-layer stacking and assembly, extending the construction period and increasing the number of on-site welding joints, leading to a decrease in electromagnetic shielding effectiveness. In high-frequency operation, the single-path copper busbar current-carrying design results in significant eddy current losses due to the eddy current effect, while also causing excessive localized temperature rise around the copper busbar, significantly accelerating the aging of component materials. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a compact DC transformer structure.

[0005] The present invention adopts the following technical solution: The present invention discloses a compact DC transformer structure, including: an oil-immersed transformer, a low-voltage section and a high-voltage section; the high-voltage section is supported above the low-voltage section by a number of insulator assemblies, and the oil-immersed transformer is located on one side of the low-voltage section; an external incoming line inputs current to the power module of the low-voltage section for inversion, and the inverted current is input to the oil-immersed transformer for boosting through a symmetrical copper busbar current-sharing structure on both sides of the power module, and the boosted current is input to the high-voltage diode valve string of the high-voltage section for series boosting, and the series boosted current is output through the high-voltage section outgoing line.

[0006] According to the aforementioned compact DC transformer structure, the external input line is connected to the DC side of the power module via a second copper busbar and a first copper busbar.

[0007] According to the aforementioned compact DC transformer structure, the power module is connected to the first stacked busbar via a third copper busbar and a fourth copper busbar respectively; the first stacked busbar is connected in parallel with two low-voltage support capacitors.

[0008] According to the aforementioned compact DC transformer structure, the first AC side of the power module is connected to the second laminated busbar via the fifth and sixth copper busbars respectively; the second AC side of the power module is connected to the third laminated busbar via the thirteenth and fourteenth copper busbars respectively.

[0009] According to the aforementioned compact DC transformer structure, one end of the second laminated busbar is sequentially connected to the incoming terminal of the oil-immersed transformer via the seventh, eighth, and ninth copper busbars, and the other end is sequentially connected to the outgoing terminal of the oil-immersed transformer via the tenth, eleventh, and twelfth copper busbars; one end of the third laminated busbar is sequentially connected to the incoming terminal of the oil-immersed transformer via the fifteenth and sixteenth copper busbars, connecting the ninth copper busbar and the oil-immersed transformer, and the other end is sequentially connected to the outgoing terminal of the oil-immersed transformer via the seventeenth, eighteenth, and twelfth copper busbars.

[0010] According to the aforementioned compact DC transformer structure, the oil-immersed transformer is connected to one set of high-voltage diode valve strings via a first cable, and the oil-immersed transformer is connected to another set of high-voltage diode valve strings via a second cable; the high-voltage diode valve string set includes a pair of high-voltage diode valve strings arranged in series.

[0011] According to the aforementioned compact DC transformer structure, in one group of high-voltage diode valve strings, one high-voltage diode valve string is connected to a high-voltage support capacitor on one side via a nineteenth copper busbar, and the other high-voltage diode valve string is connected to a high-voltage support capacitor on one side via a twentieth copper busbar; in another group of high-voltage diode valve strings, one high-voltage diode valve string is connected to a high-voltage support capacitor on one side via a twenty-first copper busbar, and the other high-voltage diode valve string is connected to a high-voltage support capacitor on one side via a twenty-second copper busbar.

[0012] According to the aforementioned compact DC transformer structure, an outlet pipe and an inlet pipe are provided between the oil-immersed transformer and the power module to dissipate heat from the power module and high-voltage diode valve string inside the DC transformer.

[0013] According to the aforementioned compact DC transformer structure, the DC transformer structure includes: a plurality of corresponding numbers of oil-immersed transformers, a low-voltage section and a high-voltage section; the plurality of low-voltage sections are connected in series in sequence, and each low-voltage section corresponds to one oil-immersed transformer and one high-voltage section.

[0014] According to the aforementioned compact DC transformer structure, multiple high-voltage sections are connected in series via copper busbars. After being stepped up in series, the voltage is connected to the high-voltage output lines via the 25th and 26th copper busbars, respectively.

[0015] Compared with the prior art, the beneficial effects of the present invention include at least the following: The present invention uses an upper and lower layer design, with the upper layer designed as a high-voltage section and the lower layer designed as a low-voltage section. The lower low-voltage section achieves dual-path current sharing through a symmetrical copper busbar current sharing structure, and then the current is stepped up by an oil-immersed transformer. The stepped-up current is directly returned to the upper high-voltage section. After the high-voltage section is stepped up in series, the current is output from the high-voltage line without exiting. This effectively utilizes the space in the height direction of the container, increases the internal power density, reduces the footprint of the DC transformer device, reduces the container size, reduces the container manufacturing cost, and also reduces civil construction costs. The reduced container size allows for direct delivery to the site after assembly, reducing on-site construction difficulty and costs.

[0016] This invention reduces the single conductor current by 40%-60% through a symmetrical copper busbar current sharing structure, effectively suppressing large currents. When operating at high frequencies, it avoids the large eddy current losses caused by the eddy current effect, and also avoids the problem of excessive local temperature rise around the copper busbar, which significantly accelerates the aging of device materials. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this disclosure 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 some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 is a top view of a compact DC transformer structure provided in an embodiment of the present invention; Figure 2 is a perspective view of a compact DC transformer structure provided in an embodiment of the present invention; Figure 3 is a front view of a compact DC transformer structure provided in an embodiment of the present invention; Figure 4 is a perspective view of a compact DC transformer structure provided in an embodiment of the present invention; Figure 5 is a partial view of a compact DC transformer structure provided in an embodiment of the present invention; Figure 6 is a partial view of a compact DC transformer structure provided in an embodiment of the present invention; Figure 7 is a partial view of a compact DC transformer structure provided in an embodiment of the present invention; In the figures: 1, water outlet pipe; 2, water inlet pipe; 3, nineteenth copper busbar; 4, twentieth copper busbar; 5, twenty-first copper busbar; 6, twenty-second copper busbar; 7, first cable; 8, second cable; 9, oil-immersed transformer; 10, low-voltage support capacitor; 11, ... 11. First stacked busbar; 12. Third copper busbar; 13. Fourth copper busbar; 14. First copper busbar; 15. Second copper busbar; 16. Ninth copper busbar; 17. Twenty-seventh copper busbar; 18. Twelfth copper busbar; 19. Tenth copper busbar; 20. Twenty-eighth copper busbar; 21. First resonant capacitor; 22. Fifth copper busbar; 23. Sixth copper busbar; 24. Power module; 25. Thirteenth copper busbar; 26. Fourteenth copper busbar; 27. Second resonant capacitor; 28. 25. High-voltage support capacitor; 30. Twenty-third copper busbar; 31. Twenty-fourth copper busbar; 32. Eleventh copper busbar; 33. Second laminated busbar; 34. Eighth copper busbar; 35. Seventh copper busbar; 36. Seventeenth copper busbar; 37. Third laminated busbar; 38. Fifteenth copper busbar; 39. Eighteenth copper busbar; 40. Sixteenth copper busbar; 41. High-voltage diode valve string; 42. Insulator assembly; 43. Twenty-sixth copper busbar. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0020] In the description of this invention, it should be noted that the terms "front," "rear," "inner," "outer," "right," "left," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] As shown in Figures 1-7, the present invention provides a compact DC transformer structure, including: an oil-immersed transformer 9, a low-voltage section and a high-voltage section.

[0023] The high-voltage section is supported above the low-voltage section by a number of insulator assemblies 42, and the oil-immersed transformer 9 is located on one side of the low-voltage section.

[0024] Preferably, but not limitingly, the oil-immersed transformer 9 may be an oil-immersed high-frequency DC transformer.

[0025] The external input line inputs current to the power module 24 in the low-voltage section for inversion. The inverted current is then fed into the oil-immersed transformer 9 through the symmetrical copper busbar current sharing structure on both sides of the power module 24 for voltage boosting. The boosted current is then fed into the high-voltage diode valve string 41 in the high-voltage section for series voltage boosting. The boosted current is then output through the high-voltage section output line.

[0026] Preferably, but not limitingly, the external input line is connected to the DC side of the power module 24 via the second copper busbar 15 and the first copper busbar 14 in sequence.

[0027] Preferably, but not limitingly, the power module 24 is connected to the first stacked busbar 11 via the third copper busbar 12 and the fourth copper busbar 13 respectively; that is, the power module 24 is connected to the first stacked busbar 11 via the third copper busbar 12, and the power module 24 is also connected to the first stacked busbar 11 via the fourth copper busbar 13.

[0028] The first stacked busbar 11 is connected in parallel with two low-voltage support capacitors 10.

[0029] Preferably, but not limitingly, the first AC side of the power module 24 is connected to the second stacked busbar 33 via the fifth copper busbar 22 and the sixth copper busbar 23, respectively.

[0030] Further preferably, but not limitingly, the second stacked busbar 33 is connected to the first resonant capacitor 21.

[0031] Further preferred but not limiting, one end of the second stacked busbar 33 is connected in sequence to the seventh copper busbar 35, the eighth copper busbar 34, the ninth copper busbar 16 and the incoming terminal of the oil-immersed transformer 9, and the other end is connected in sequence to the tenth copper busbar 19, the eleventh copper busbar 32, the twelfth copper busbar 18 and the outgoing terminal of the oil-immersed transformer 9.

[0032] Preferably, but not limitingly, the second AC side of the power module 24 is connected to the third stacked busbar 37 via the thirteenth copper busbar 25 and the fourteenth copper busbar 26.

[0033] Further preferably, but not limitingly, the third stacked busbar 37 is connected to the second resonant capacitor 27.

[0034] Further preferred but not limiting, one end of the third stacked busbar 37 is connected in sequence through the fifteenth copper busbar 38, the sixteenth copper busbar 40, the incoming terminal connecting the ninth copper busbar 16 and the oil-immersed transformer 9, and the other end is connected in sequence through the seventeenth copper busbar 36, the eighteenth copper busbar 39, the twelfth copper busbar 18 and the outgoing terminal of the oil-immersed transformer 9.

[0035] Preferably, but not limitingly, the oil-immersed transformer 9 is connected to one of the high-voltage diode valve strings via a first cable 7, and the oil-immersed transformer 9 is connected to another high-voltage diode valve string via a second cable 8.

[0036] The high-voltage diode valve string group includes a pair of high-voltage diode valve strings 41 arranged in series.

[0037] Further preferred but not limiting, a pair of high-voltage diode valve strings 41 in one set of the high-voltage diode valve strings is connected in series via a twenty-seventh copper busbar 17; a pair of high-voltage diode valve strings 41 in another set of the high-voltage diode valve strings is connected in series via a twenty-eighth copper busbar 20.

[0038] Further preferred but not limiting, one high-voltage diode valve string 41 of one group of high-voltage diode valve strings is connected to the high-voltage support capacitor 29 on one side of it through the nineteenth copper busbar 3, and the other high-voltage diode valve string 41 is connected to the high-voltage support capacitor 29 on one side of it through the twentieth copper busbar 4, that is, a pair of high-voltage diode valve strings 41 are connected in parallel with the high-voltage support capacitor 29 on their corresponding sides.

[0039] Further preferred but not limiting, one high-voltage diode valve string 41 of another high-voltage diode valve string group is connected to the high-voltage support capacitor 29 on one side of it through the twenty-first copper busbar 5, and the other high-voltage diode valve string 41 is connected to the high-voltage support capacitor 29 on one side of it through the twenty-second copper busbar 6, that is, a pair of high-voltage diode valve strings 41 and their corresponding high-voltage support capacitors 29 are connected in parallel.

[0040] Preferably, but not limitingly, the DC transformer structure includes: a plurality of corresponding numbers of oil-immersed transformers 9, a low-voltage section and a high-voltage section; the plurality of low-voltage sections are connected in series in sequence, and each low-voltage section corresponds to one oil-immersed transformer 9 and one high-voltage section.

[0041] Further preferred, but not limiting, multiple high-voltage sections are connected in series via copper busbars. After being boosted in series, they are connected to the output lines of the high-voltage sections via the 25th copper busbar 28 and the 26th copper busbar 43, respectively.

[0042] In this embodiment, in order to boost the voltage to 100KV, three 33.4KV oil-immersed transformers 9 are connected in series to boost the voltage, forming a compact 100KV DC transformer structure.

[0043] In this embodiment, three oil-immersed transformers 9, three low-voltage sections and three high-voltage sections are provided.

[0044] The three high-voltage sections are connected in series via the 23rd copper busbar 30 and the 24th copper busbar 31. After being stepped up in series, they are connected to the high-voltage section output lines via the 25th copper busbar 28 and the 26th copper busbar 43, respectively.

[0045] Preferably, but not limitingly, an outlet pipe 1 and an inlet pipe 2 are provided between the oil-immersed transformer 9 and the power module 24 to dissipate heat from the power module 24 and the high-voltage diode valve string 41 inside the DC transformer.

[0046] In other embodiments, different numbers of oil-immersed transformers 9 can be used in series to boost the voltage to achieve the desired final voltage.

[0047] Compared with the prior art, the beneficial effects of the present invention include at least the following: The present invention uses an upper and lower layer design, with the upper layer designed as a high-voltage section and the lower layer as a low-voltage section. The lower low-voltage section uses a symmetrical copper busbar current sharing structure to achieve dual-path current sharing before the current is stepped up by an oil-immersed transformer. The stepped-up current is directly returned to the upper high-voltage section. After the high-voltage section is stepped up in series, the current is output from the high-voltage line. This effectively utilizes the space in the height direction of the container, increases the internal power density, reduces the footprint of the DC transformer device, reduces the container size, reduces the container manufacturing cost, and also reduces civil construction costs. The reduced container size allows for direct delivery to the site after assembly, reducing on-site construction difficulty and costs. It also reduces the overall volume and footprint, facilitating on-site installation and layout.

[0048] This invention reduces the single conductor current by 40%-60% through a symmetrical copper busbar current sharing structure, effectively suppressing large currents. When operating at high frequencies, it avoids the large eddy current losses caused by the eddy current effect, and also avoids the problem of excessive local temperature rise around the copper busbar, which significantly accelerates the aging of device materials.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A compact DC transformer structure, characterized in that, include: Oil-immersed transformer (9), low-voltage section and high-voltage section; the high-voltage section is supported above the low-voltage section by several insulator assemblies (42), and the oil-immersed transformer (9) is located on one side of the low-voltage section; the external incoming line inputs current into the power module (24) of the low-voltage section for inversion, and the inverted current is input into the oil-immersed transformer (9) for boosting through the symmetrical copper busbar current sharing structure on both sides of the power module (24), and the boosted current is input into the high-voltage diode valve string (41) of the high-voltage section for series boosting, and the series boosted current is output through the high-voltage section outgoing line.

2. The compact DC transformer structure according to claim 1, characterized in that: The external incoming line is connected to the DC side of the power module (24) in sequence through the second copper busbar (15) and the first copper busbar (14).

3. The compact DC transformer structure according to claim 1, characterized in that: The power module (24) is connected to the first stacked busbar (11) through the third copper busbar (12) and the fourth copper busbar (13); the first stacked busbar (11) is connected in parallel with two low-voltage support capacitors (10).

4. The compact DC transformer structure according to claim 1, characterized in that: The first AC side of the power module (24) is connected to the second stacked busbar (33) via the fifth copper busbar (22) and the sixth copper busbar (23); the second AC side of the power module (24) is connected to the third stacked busbar (37) via the thirteenth copper busbar (25) and the fourteenth copper busbar (26).

5. A compact DC transformer structure according to claim 4, characterized in that: One end of the second stacked busbar (33) is connected to the incoming terminals of the seventh copper busbar (35), the eighth copper busbar (34), the ninth copper busbar (16) and the oil-immersed transformer (9) in sequence, and the other end is connected to the outgoing terminals of the tenth copper busbar (19), the eleventh copper busbar (32), the twelfth copper busbar (18) and the oil-immersed transformer (9) in sequence; one end of the third stacked busbar (37) is connected to the incoming terminals of the ninth copper busbar (16) and the oil-immersed transformer (9) in sequence through the fifteenth copper busbar (38), the sixteenth copper busbar (40), and the fifteenth copper busbar (16), and the oil-immersed transformer (9) in sequence, and the other end is connected to the outgoing terminals of the seventeenth copper busbar (36), the eighteenth copper busbar (39), the twelfth copper busbar (18) and the oil-immersed transformer (9) in sequence.

6. The compact DC transformer structure according to claim 1, characterized in that: The oil-immersed transformer (9) is connected to one of the high-voltage diode valve strings via a first cable (7), and the oil-immersed transformer (9) is connected to another high-voltage diode valve string via a second cable (8); the high-voltage diode valve string includes a pair of high-voltage diode valve strings (41) arranged in series.

7. A compact DC transformer structure according to claim 6, characterized in that: One high-voltage diode valve string (41) of one high-voltage diode valve string group is connected to the high-voltage support capacitor (29) on one side through the nineteenth copper busbar (3), and the other high-voltage diode valve string (41) is connected to the high-voltage support capacitor (29) on one side through the twentieth copper busbar (4); one high-voltage diode valve string (41) of another high-voltage diode valve string group is connected to the high-voltage support capacitor (29) on one side through the twenty-first copper busbar (5), and the other high-voltage diode valve string (41) is connected to the high-voltage support capacitor (29) on one side through the twenty-second copper busbar (6).

8. A compact DC transformer structure according to claim 1, characterized in that: A water outlet pipe (1) and a water inlet pipe (2) are provided between the oil-immersed transformer (9) and the power module (24) to dissipate heat from the power module (24) and the high-voltage diode valve string (41) inside the DC transformer.

9. A compact DC transformer structure according to claim 1, characterized in that: The DC transformer structure includes: multiple corresponding oil-immersed transformers (9), a low-voltage section and a high-voltage section; multiple low-voltage sections are connected in series in sequence, and each low-voltage section corresponds to an oil-immersed transformer (9) and a high-voltage section.

10. A compact DC transformer structure according to claim 9, characterized in that: Multiple high-voltage sections are connected in series via copper busbars. After being stepped up in series, they are connected to the high-voltage section output lines via the 25th copper busbar (28) and the 26th copper busbar (43).

Images