A dual-split rectifier split transformer

Abstract

This utility model relates to the field of transformer technology, specifically to a double-split rectifier split transformer, including a housing and a three-phase winding assembly disposed within the housing. Each phase winding assembly includes an iron core, an inner coil wound along the axial direction of the iron core, and an outer coil wound along the axial direction of the inner coil. The inner coil has a cylindrical structure, and the outer coil is split axially into upper and lower coils. The three upper coils are connected end-to-end via a D-connection, and the three lower coils share a neutral point via a Y-connection. This utility model, based on a fully dry insulation system, solves multiple technical contradictions in an extremely compact space, namely high ripple suppression, maintenance-free operation, and ultra-small space occupation, providing an efficient and reliable rectification solution for high-voltage, high-current testing environments.

Description

Technical Field

[0001] This utility model relates to the field of transformer technology, and in particular to a double-split rectifier split transformer. Background Technology

[0002] The rapid development of high-voltage direct current (HVDC) transmission technology has placed higher demands on test power systems, especially in test scenarios at voltage levels of ±60kV and above. Traditional rectifier transformers face multiple technical bottlenecks: On the one hand, oil-immersed transformers are difficult to adapt to high-density equipment deployment environments due to the risk of insulating oil leakage, while conventional dry-type transformers are bulky due to the limited layout of the outer coils. For example, to achieve 12-pulse rectification, two independent transformers often need to be connected in parallel, which not only occupies space but also increases system complexity. On the other hand, when attempting to place the high-voltage secondary coil inside to reduce volume, the traditional layered insulation design cannot effectively control the electric field distribution at the 45kV level, easily causing partial discharge problems. At the same time, the insufficient stability of the high-current lead structure leads to increased electromagnetic vibration, directly affecting output accuracy and equipment lifespan. The practical experience of projects such as the ±60kV test power supply of the State Grid Smart Research Institute shows that existing solutions have significant gaps in meeting the triple requirements of "high ripple suppression rate, compact packaging, and maintenance-free operation," and there is an urgent need for a new type of dry-type structure to achieve efficient 12-pulse rectification output within a limited space. Utility Model Content

[0003] The technical problem to be solved by this utility model embodiment is to provide a dual-split rectifier split transformer to solve the problem that a single dry-type rectifier transformer in the prior art cannot simultaneously achieve high voltage and high current output and 12-pulse low ripple rectification in a compact space.

[0004] This utility model discloses a double-split rectifier split transformer, including a housing and a three-phase winding assembly disposed within the housing. Each phase of the winding assembly includes an iron core, an inner coil wound along the axial direction of the iron core, and an outer coil wound along the axial direction of the inner coil. The inner coil has a cylindrical structure, and the outer coil is split axially into an upper coil and a lower coil. The three upper coils are connected end-to-end via a D-connection, and the three lower coils are connected to a common neutral point via a Y-connection.

[0005] Optionally, the upper part of the upper coil is provided with a first upper lead terminal, and the lower part of the upper coil is provided with a first lower lead terminal. The three phase upper coils are connected by a D-connection through the first upper lead terminal and the first lower lead terminal, and the first lower lead terminal of the upper coil constitutes the output terminal of the D-connection.

[0006] Optionally, the upper part of the lower coil is provided with a second upper lead terminal, the lower part of the lower coil is provided with a second lower lead terminal, the three phases of the lower coil are Y-connected through the second lower lead terminal, and the second upper lead terminal of the lower coil constitutes the output terminal of the Y connection.

[0007] Optionally, the housing is provided with a first through-wall bushing that corresponds one-to-one with each output terminal of the outer coil.

[0008] Optionally, the dual-split rectifier split transformer further includes a first lead copper tube, the three-phase upper coils are connected by a D-connection through the first lead copper tube, and the three-phase lower coils are connected by a Y-connection through another first lead copper tube.

[0009] Optionally, an insulating pad is provided between the upper coil and the corresponding lower coil, and a first epoxy board is provided on the inner wall of the housing along the direction of the first lead copper tube, with each first lead copper tube disposed on the corresponding first epoxy board.

[0010] Optionally, the inner coil has an upper lead at the top and a lower lead at the bottom. The three-phase inner coils are connected end-to-end via the upper and lower leads using a D-connection, and the upper lead of the inner coil forms the output terminal of the D-connection.

[0011] Optionally, the dual-split rectifier split transformer further includes a second lead copper tube arranged outside the outer coil. The upper lead is led out from the top of the inner coil and connected to the second lead copper tube at the corresponding position. The lower lead is led out from the bottom of the inner coil and connected to the second lead copper tube at the corresponding position. A second epoxy plate is provided on the inner wall of the housing along the direction of the second lead copper tube, and each second lead copper tube is located on the corresponding second epoxy plate.

[0012] Optionally, the housing is provided with a second through-wall bushing that corresponds one-to-one with each output terminal of the inner coil.

[0013] Optionally, the inner coil has a segmented structure along the axis.

[0014] Compared with the prior art, the beneficial effects of the dual-split rectifier split transformer provided in this embodiment of the present invention are as follows:

[0015] By employing a cylindrical continuous winding pattern for the inner coil (as the 10kV input side) and symmetrically splitting the outer coil into an upper and lower double-layer structure along the axial direction (as the 45kV output side), with the upper coil of the outer coil using a delta connection (D-connection) and the lower coil using a star connection (Y-connection), two sets of rectifier paths with different phases are naturally formed within a single transformer, directly achieving 12-pulse output conditions and significantly reducing current ripple. The cylindrical inner coil layout significantly optimizes the high-voltage electric field distribution within the confined space, effectively controlling the field strength concentration phenomenon at weak insulation points and eliminating the risk of partial discharge. The axial double-split structure of the outer coil ensures symmetry in electromagnetic coupling, simultaneously strengthening the structural stability of the high-current leads and significantly suppressing the impact of operating vibration on output accuracy. Therefore, this invention, based on a fully dry insulation system, solves multiple technical contradictions in an extremely compact space—namely, high ripple suppression, maintenance-free operation, and ultra-small space occupation—providing an efficient and reliable rectification solution for high-voltage, high-current testing environments. Attached Figure Description

[0016] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0017] Figure 1 This is a schematic diagram of the overall structure of the dual-split rectifier split transformer provided in an embodiment of the present utility model;

[0018] Figure 2 A schematic cross-sectional view of the inner and outer coils provided for an embodiment of this utility model;

[0019] Figure 3 A schematic diagram of the structure of the inner coil and the outer coil in accordance with an embodiment of this utility model;

[0020] Figure 4 A schematic diagram of the bidirectional split wiring of the inner coil provided in an embodiment of this utility model;

[0021] Figure 5 A schematic diagram of the assembly of the inner coil and outer coil with the housing provided for an embodiment of this utility model;

[0022] Figure 6 This is a schematic diagram of the assembly of the first epoxy board and the shell provided in an embodiment of the present utility model;

[0023] Figure 7 This is a schematic diagram of the assembly of the second epoxy plate and the shell provided in an embodiment of the present invention.

[0024] The labels for the attached figures are as follows:

[0025] 1. Iron core; 2. Outer coil; 21. Upper coil; 211. First upper lead terminal; 212. First lower lead terminal; 22. Lower coil; 221. Second upper lead terminal; 222. Second lower lead terminal; 23. First through-wall bushing; 24. First lead copper tube; 25. First epoxy board; 3. Inner coil; 31. Upper lead; 32. Lower lead; 33. Second lead copper tube; 34. Second epoxy board; 35. Second through-wall bushing. Detailed Implementation

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The preferred embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0027] This utility model discloses a dual-split rectifier split transformer, such as Figures 1-4 As shown, the device includes a housing and a three-phase winding assembly disposed within the housing. Each phase winding assembly includes an iron core 1, an inner coil 3 wound along the axial direction of the iron core 1, and an outer coil 2 wound along the axial direction of the inner coil 3. The inner coil 3 has a cylindrical structure, and the outer coil 2 is split axially into an upper coil 21 and a lower coil 22. The three upper coils 21 are connected end-to-end via a D-connection, and the three lower coils 22 are connected to the neutral point via a Y-connection.

[0028] By implementing the above-described embodiment of a double-split rectifier transformer, and utilizing the reconfigured winding structure and connection method, the technical barrier of incompatibility between high voltage and high current and low ripple rectification in a compact space can be overcome within a single device. The inner coil 3 is designed as a continuously wound cylindrical structure as the input side, while the outer coil 2 is precisely split axially into two completely independent parts: an upper coil 21 and a lower coil 22. This structural configuration enables a single transformer to simultaneously output two AC currents of different phases. Specifically, the three-phase upper coil 21 forms a closed loop through a D-connection, while the three-phase lower coil 22 converges at the neutral point through a Y-connection. The two connection methods naturally create a 30° phase difference in electrical characteristics. Only a single transformer is needed to directly construct the underlying topology of two sets of six-pulse rectifier bridges operating in parallel, achieving twelve-pulse rectified output from the power source, resulting in a significant improvement in ripple suppression compared to traditional solutions. Secondly, the continuous cylindrical winding pattern of the inner coil 3 on the input side creates an extremely uniform radial electric field distribution within the highly compressed cavity, achieving circumferential equipotential control over the high-voltage electric field of up to 45kV on the output side, thus resolving the persistent problem of partial discharge caused by interlayer field strength distortion. The outer coil 2 on the output side, with its axially split structure, forms complete electromagnetic circuits with the upper coil 21 and lower coil 22. Their axially symmetrical layout ensures coaxial and equidistant fully symmetrical magnetic coupling with the inner coil 3 on the input side, completely eliminating the bias magnetization phenomenon caused by traditional asymmetrical windings. This electromagnetic symmetry, combined with the rigid interconnection structure of the high-current leads, significantly enhances the transformer's resistance to short-circuit electromagnetic forces, physically suppressing vibration and noise interference with output accuracy. Therefore, the fully dry insulation system of this embodiment completely eliminates the need for oil immersion design, removing the risk of leakage maintenance. The axially split structure provides a distributed heat dissipation path for the high-voltage output port, and the compact housing packaging achieves a breakthrough optimization of overall power density. This integrates the electric field optimization capability of the inner cylindrical coil 3, the rectification phase generation capability of the outer coil 2 with axial double splitting, the electromagnetic symmetry enhancement capability of the upper and lower structure, and the dry insulation maintenance-free capability into a single device, providing a solution for space-sensitive scenarios such as high-voltage test chambers that simultaneously meets the requirements of millimeter-level size compression, nanosecond-level ripple suppression, and thousand-hour-level maintenance-free operation.

[0029] Preferably, both the inner coil 3 and the outer coil 2 are epoxy resin vacuum-cast coils, and the housing is a steel plate shell.

[0030] Furthermore, the upper part of the upper coil 21 is provided with a first upper lead 31 terminal 211, and the lower part of the upper coil 21 is provided with a first lower lead 32 terminal 212. The three-phase upper coils 21 are connected by a D-connection through the first upper lead 31 terminal 211 and the first lower lead 32 terminal 212, and the first lower lead 32 terminal 212 of the upper coil 21 constitutes the output terminal of the D-connection.

[0031] Furthermore, the upper part of the lower coil 22 is provided with a second upper lead 31 terminal 221, and the lower part of the lower coil 22 is provided with a second lower lead 32 terminal 222. The three-phase lower coils 22 are Y-connected through the second lower lead 32 terminal 222, and the second upper lead 31 terminal 221 of the lower coil 22 constitutes the output terminal of the Y connection.

[0032] Furthermore, combined Figure 5 As shown, the housing is provided with a first through-wall bushing 23 that corresponds one-to-one with each output terminal of the outer coil 2.

[0033] Furthermore, the dual-split rectifier split transformer also includes a first lead copper tube 24, the three-phase upper coils 21 are connected by a D-connection through the first lead copper tube 24, and the three-phase lower coils 22 are connected by a Y-connection through another first lead copper tube 24.

[0034] By implementing the above-described dual-split rectifier split transformer embodiment, the layout topology of the first upper lead 31 terminal 211 and the first lower lead 32 terminal 212 of the upper coil 21, and the second upper lead 31 terminal 221 and the second lower lead 32 terminal 222 of the lower coil 22, optimizes the three-phase topology construction on the axially split outer coil 2 structure. Specifically, the three-phase upper coils 21 are connected by a first lead copper tube 24 to form a closed D-connection circuit with their first upper lead 31 terminal 211 and first lower lead 32 terminal 212. Simultaneously, the first lower lead 32 terminal 212 serves as the output terminal of the D-connection system, vertically separating the AC output lead paths with different phases. The three-phase lower coils 22 are interconnected by another first lead copper tube 24 with their second lower lead 32 terminal 222 forming a Y-connection neutral point. The second upper lead 31 terminal 221 serves as the output terminal of the Y-connection system. This reverse design of the double-layer output terminals (upper layer using lower terminals, lower layer using upper terminals) significantly compresses the lead bridging space. Furthermore, by precisely matching the physical positions of the first through-wall bushing 23 group configured on the housing with each output terminal (including the upper first lower lead 32 terminal 212, the lower second upper lead 31 terminal 221, and the D / Y neutral point), a fully sealed 45kV output terminal is achieved through the metal housing. The first lead copper tube 24 is made of high-rigidity, thick-walled tubing, which not only accurately conducts the three-phase circulating current but also forms an electromagnetic shield. The three-dimensional rigid frame formed by its welding with the coil terminals completely eliminates lead resonance caused by high-current pulses. Combined with the mechanical locking effect of the wall bushing, three core effects are achieved simultaneously in a limited space: the low inductance connection of the first lead copper tube 24 improves the phase accuracy of the 12-pulse wave; the reverse layout of the multi-layer output terminals greatly compresses the longitudinal space; and the fully sealed through-system of the first wall bushing 23 doubles the withstand voltage of the dry insulation shell, ultimately establishing a lossless energy transmission channel with zero vibration interference in ±60kV application scenarios.

[0035] Furthermore, combined Figure 6 As shown, an insulating pad is provided between the upper coil 21 and the corresponding lower coil 22. A first epoxy plate 25 is provided on the inner wall of the housing along the direction of the first lead copper tube 24, and each first lead copper tube 24 is provided on the corresponding first epoxy plate 25.

[0036] Through the implementation of the above-described dual-split rectifier split transformer embodiment, an axial composite barrier is constructed between the upper coil 21 and the lower coil 22 using an insulating isolation pad, effectively isolating the potential difference creepage path between the two output coils, and simultaneously achieving electrical insulation and mechanical stress buffering. The first epoxy board 25 laid along the inner wall of the casing forms a full-path positioning base, and the spatial three-dimensional coordinates of each first lead copper tube 24 are fixed by precise slotting. Under the premise of ensuring the rigid connection of the three-phase D / Y connection topology, its high bending modulus characteristics significantly suppress the micro-vibration of the copper tubes caused by large current pulses. Therefore, in this embodiment of the utility model, the insulating isolation pad and the first epoxy board 25 work together to form a rigid-flexible composite insulation system. The former blocks the risk of axial discharge between coil layers, and the latter eliminates the hidden danger of radial displacement of the lead system, so that the all-dry insulation environment of the 45kV output terminal is doubly reinforced. The system suppresses corona at the bushing root by solidifying the equipotential distribution of the first lead copper tube 24, and absorbs the thermal expansion deformation of the winding by using the insulating isolation pad. Ultimately, a three-dimensional stable output structure that is resistant to electromagnetic vibration, thermal stress deformation and partial discharge is established in an extremely compact space.

[0037] Furthermore, combined Figure 2 and Figure 7 As shown, the top of the inner coil 3 is provided with an upper lead 31, and the bottom of the inner coil 3 is provided with a lower lead 32. The three-phase inner coils 3 are connected end to end through the upper lead 31 and the lower lead 32 in a D-connection manner, and the upper lead 31 of the inner coil 3 constitutes the output terminal of the D-connection.

[0038] Furthermore, the dual-split rectifier split transformer also includes a second lead copper tube 33 arranged outside the outer coil 2. The upper lead 31 is led out from the top of the inner coil 3 and connected to the second lead copper tube 33 at the corresponding position. The lower lead 32 is led out from the bottom of the inner coil 3 and connected to the second lead copper tube 33 at the corresponding position. A second epoxy plate 34 is arranged on the inner wall of the housing along the direction of the second lead copper tube 33, and each second lead copper tube 33 is located on the corresponding second epoxy plate 34.

[0039] Furthermore, looking back Figure 5 The housing is provided with a second through-wall bushing 35 that corresponds one-to-one with each output terminal of the inner coil 3.

[0040] Furthermore, the inner coil 3 has a segmented structure along the axis.

[0041] Through the implementation of the above-described dual-split rectifier transformer embodiment, the segmented structure of the inner coil 3 allows the inner coil 3 to construct a continuous electrical circuit through the upper lead 31 and the lower lead 32. Its axially distributed multi-segment physical structure, while maintaining the overall electrical continuity of the winding, utilizes the segment gaps to form a natural longitudinal field strength suppression zone. The upper lead 31, extending from the top of the uppermost segment, achieves three-phase D-connection circulating current through the second lead copper tube 33, simultaneously serving as the output terminal convergence point. This, combined with the dual-path layout vertically led out by the bottom lower lead 32, maximizes space compression. The second epoxy board 34 laid along the inner wall of the casing provides a rigid positioning base for the second lead copper tube 33, eliminating the risk of copper tube displacement caused by large input current. Therefore, this embodiment of the invention, through the segmented structure of the inner coil 3 combined with the horizontally extending second lead copper tube 33, constitutes a composite electric field control system: the segment gaps discretize the longitudinal potential distribution, the horizontal copper tube eliminates cross-field coupling, and the vertical lead penetration achieves efficient utilization of space in the depth direction of the casing. Secondly, the second through-wall bushing 35 group configured on the casing independently isolates the high-current leads on the input side of the inner coil 3, forming a three-dimensional isolation barrier with the first through-wall bushing 23 corresponding to the output side of the outer coil 2. The entire input-side architecture can simultaneously achieve triple-combined gain within a single transformer: the discrete potential distribution characteristics of the segmented inner coil 3 improve the uniformity of the inter-turn field strength at the 10kV level; the horizontal wiring and vertical terminal layout of the second lead copper tube 33 double the space compression ratio; and the independent through-system of input and output bushings achieves zero cross-field interference in a fully dry insulation environment, establishing a lossless energy conversion channel for high-voltage, high-current transmission.

[0042] It should be understood that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some of the technical features; and all such modifications and substitutions should fall within the protection scope of the appended claims of this utility model.

Claims

1. A dual-split rectifier split transformer, characterized in that: The dual-split rectifier split transformer includes a housing and a three-phase winding assembly disposed within the housing; Each phase of the winding assembly includes an iron core, an inner coil wound along the axial direction of the iron core, and an outer coil wound along the axial direction of the inner coil. The inner coil has a cylindrical structure, and the outer coil is split into an upper coil and a lower coil along the axial direction. The upper coils of the three phases are connected end-to-end via a D-connection, and the lower coils of the three phases are connected to a common neutral point via a Y-connection.

2. The dual-split rectifier split transformer according to claim 1, characterized in that: The upper part of the upper coil is provided with a first upper lead terminal, and the lower part of the upper coil is provided with a first lower lead terminal. The three phase upper coils are connected by a D-connection through the first upper lead terminal and the first lower lead terminal, and the first lower lead terminal of the upper coil constitutes the output terminal of the D-connection.

3. The dual-split rectifier split transformer according to claim 2, characterized in that: The lower coil has a second upper lead terminal on its upper part and a second lower lead terminal on its lower part. The three lower coils are connected by a Y-connection through the second lower lead terminal, and the second upper lead terminal of the lower coil constitutes the output terminal of the Y-connection.

4. The dual-split rectifier split transformer according to claim 3, characterized in that: The housing is provided with a first through-wall sleeve that corresponds one-to-one with each output terminal of the outer coil.

5. The dual-split rectifier split transformer according to claim 3, characterized in that: The dual-split rectifier split transformer also includes a first lead copper tube. The three-phase upper coils are connected by a D-connection through the first lead copper tube, and the three-phase lower coils are connected by a Y-connection through another first lead copper tube.

6. The dual-split rectifier split transformer according to claim 5, characterized in that: An insulating pad is provided between the upper coil and the corresponding lower coil. A first epoxy board is provided on the inner wall of the housing along the direction of the first lead copper tube, and each of the first lead copper tubes is disposed on the corresponding first epoxy board.

7. The dual-split rectifier split transformer according to claim 1, characterized in that: The inner coil has an upper lead at its top and a lower lead at its bottom. The three-phase inner coils are connected end-to-end via the upper and lower leads using a D-connection, and the upper lead of the inner coil forms the output terminal of the D-connection.

8. The dual-split rectifier split transformer according to claim 7, characterized in that: The dual-split rectifier split transformer also includes a second lead copper tube arranged outside the outer coil. The upper lead is led out from the top of the inner coil and connected to the second lead copper tube at the corresponding position. The lower lead is led out from the bottom of the inner coil and connected to the second lead copper tube at the corresponding position. A second epoxy plate is provided on the inner wall of the housing along the direction of the second lead copper tube, and each second lead copper tube is located on the corresponding second epoxy plate.

9. The dual-split rectifier split transformer according to claim 7, characterized in that: The housing is provided with a second through-wall sleeve that corresponds one-to-one with each output terminal of the inner coil.

10. The dual-split rectifier split transformer according to claim 7, characterized in that: The inner coil has a segmented structure along the axis.

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