LIT interline 12-pulse filter phase shifter

Abstract

The application discloses an LIT interline 12-pulse filter phase shifter and relates to the technical field of filter phase shifter, which comprises a day-shaped magnetic core with an upper iron yoke, a lower iron yoke and A-phase core columns, B-phase core columns and C-phase core columns vertically connected between the upper iron yoke and the lower iron yoke; three insulation skeletons, which are correspondingly sleeved on the three core columns, and the middle part of each insulation skeleton is fixedly connected with a ring-shaped partition plate for separating the winding area of the insulation skeleton into a lower layer area and an upper layer area; and a lower layer winding, which is wound in each lower layer area and comprises a long coil wound on the lower layer area of the insulation skeleton of the phase core column. Through the layered insulation skeleton and the mirror image layout of the winding, two groups of zigzag windings with opposite cross-connection directions are integrated on the same magnetic core, ±15° phase shift outputs are simultaneously generated, the 12-pulse rectification requirement is met, the cross section of the core and the volume of the winding are greatly reduced, the manufacturing cost is reduced, and the blank between the line phase transformer (LIT) and the 12-pulse rectifier is filled.

Description

Technical Field

[0001] The present invention relates to the technical field of filtering phase shifters, and specifically relates to a 12-pulse filtering phase shifter between LIT lines. Background Art

[0002] In high-power industrial rectification systems, 12-pulse rectification topologies are usually adopted to suppress input current harmonics and improve power factor. This topology requires the front stage to provide two sets of three-phase AC voltages with equal amplitude and a phase difference of 30° to drive two sets of rectifier bridges to operate in parallel on the DC side. To achieve this phase difference, an electromagnetic energy transmission device with phase shifting function needs to be arranged between the power grid and the rectifier bridges. This type of device essentially belongs to a waveguide-type device that realizes electromagnetic wave phase transformation by using a magnetic conductive frame and winding spatial layout. Through a specific core structure and winding connection mode, a suitable voltage vector is superimposed on the original line voltage to change the amplitude and phase relationship of the voltages on both sides of the line, so as to convert a single set of input voltages into two sets of output voltages with a predetermined phase difference. The distribution and synthesis of electromagnetic energy in multiple magnetic circuit paths are involved inside the device, and there are strict requirements for the core magnetic circuit structure, winding spatial arrangement, and bridging lead layout.

[0003] The 12-pulse rectifier is one of the most widely used high-power rectification topologies in industrial applications at present. By connecting two sets of three-phase rectifier bridges in parallel on the DC side, and the AC input voltages of the two sets of bridges have a phase difference of 30°, it can effectively cancel characteristic harmonics such as the 5th, 7th, 17th, and 19th harmonics. Most of the front-end phase-shifting transformers in traditional 12-pulse rectification systems adopt an axial double-split structure (Dy0d11 combination), which has the disadvantages of large volume and high cost. As a new phase-shifting topology, the line interphase transformer (LIT) realizes voltage phase adjustment by utilizing interphase coupling. The line interphase transformer (LIT) is designed for ordinary AC lines, and its integrated application with 12-pulse rectifiers is still blank.

[0004] To solve the above problems, a 12-pulse filtering phase shifter between LIT lines is proposed. Contents of the Invention

[0005] To solve the above technical problems, a 12-pulse filtering phase shifter between LIT lines is provided, and this technical solution solves the problems raised in the above background art.

[0006] To achieve the above objectives, the present invention can be implemented by adopting the following technical solutions: The present invention provides a 12-pulse filtering phase shifter between LIT lines, comprising: A Chinese character "ri"-shaped magnetic conductive core, which has an upper yoke, a lower yoke, and an A-phase core limb, a B-phase core limb, and a C-phase core limb vertically connected between the upper yoke and the lower yoke; Three insulating frames are fitted onto three core posts in a one-to-one correspondence. Each insulating frame has a fixed annular partition in the middle to divide the winding area of ​​the insulating frame into a lower layer and an upper layer. The lower winding is wound in each lower zone. Each phase includes a long coil wound in the lower zone of the core column insulation frame of this phase, and a short coil connected to the lower zone of the core column insulation frame of another phase through a jumper wire. The end of the long coil is electrically connected to the beginning of the short coil. All jumper wires of the lower winding are arranged in the first side space of the core column. The upper winding is wound in each upper region. Each phase includes a long coil wound in the upper region of the core column insulation skeleton of this phase, and a short coil connected to the upper region of the core column insulation skeleton of another phase through a jumper wire. The end of the long coil is electrically connected to the beginning of the short coil. All the jumper wires of the upper winding are arranged in the second side space of the core column opposite to the first side core column. Among them, the target core column connected to all the jumper wires of the lower winding and the target core column connected to all the jumper wires of the upper winding have opposite transmission directions in the arrangement order of the three-phase core columns. The clamping structure is fixedly installed at the upper and lower ends of the H-shaped magnetic core; Metal encapsulation housing for housing the H-shaped magnetic core, insulating frame, windings, and clamping structure.

[0007] Furthermore, in the lower winding, the end of the long coil of phase A is connected across the beginning of the short coil of phase B core, the end of the long coil of phase B is connected across the beginning of the short coil of phase C core, and the end of the long coil of phase C is connected across the beginning of the short coil of phase A core. In the upper winding, the end of the long coil of phase A is connected to the starting end of the short coil of phase C core column, the end of the long coil of phase C is connected to the starting end of the short coil of phase B core column, and the end of the long coil of phase B is connected to the starting end of the short coil of phase A core column.

[0008] Furthermore, the ratio of the number of turns in the short coil Wb to the number of turns in the long coil Wa is: Wb / Wa=0.366, and the total number of turns is: Wab=Wa+Wb=1.366.

[0009] Furthermore, in the lower layer, the short coil is positioned close to the annular partition, while the long coil is positioned away from the annular partition; In the upper region, the short coils are positioned close to the annular partition, while the long coils are positioned away from the annular partition, so that the short coils in the lower region and the short coils in the upper region are symmetrically arranged on both sides of the annular partition.

[0010] Furthermore, it also includes an input busbar assembly and an output busbar assembly. The input busbar assembly is disposed on the first side wall of the metal package housing and includes an A-phase input terminal, a B-phase input terminal, and a C-phase input terminal. The output busbar assembly is disposed on the second side wall of the metal package housing and is divided into a first output group and a second output group. Each group includes an A-phase output terminal, a B-phase output terminal, and a C-phase output terminal. The ends of the lower windings of each phase are respectively connected to the corresponding phase output terminals of the first output group, and the ends of the upper windings of each phase are respectively connected to the corresponding phase output terminals of the second output group.

[0011] As described above, the features and advantages of the LIT line-to-line 12-pulse filter phase shifter of this invention are: This invention integrates two independent phase-shifting circuits—lower and upper windings—on the same shaped magnetic core through a layered insulation skeleton and mirrored winding layout. All the jumper wires of the lower and upper windings are arranged in opposite directions in the three-phase core column sequence, resulting in +15° and -15° phase-shifting outputs from the two windings, respectively. This structure replaces the traditional isolation transformer with an autotransformer-based zigzag connection, simultaneously achieving two voltage outputs with a 30° phase difference required for 12-pulse rectification on the same core. This significantly reduces the total number of windings and the core cross-sectional area, effectively lowering the device's size, weight, and manufacturing cost, and filling the gap in integration between line-to-line transformers (LITs) and 12-pulse rectifiers.

[0012] This invention uses a split-side wiring layout where all the lower layer winding jumpers are arranged in the space on the first side of the core post, and all the upper layer winding jumpers are arranged in the space on the opposite second side. This avoids spatial interference between the upper and lower layer jumpers and improves assembly processability and insulation reliability. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of the LIT line-to-line 12-pulse filter phase shifter shown in this invention; Figure 2 for Figure 1 Another perspective diagram of the structure; Figure 3 for Figure 1 Internal diagram of the structure; Figure 4 for Figure 3 Schematic diagram of the middle section; Figure 5 This is a schematic diagram of the insulating frame structure of the LIT line-to-line 12-pulse filter phase shifter shown in this invention; Figure 6 This is a schematic diagram of the jumper wire structure in the lower winding in an embodiment of the present invention; Figure 7is a schematic diagram of the jumper wire structure in the upper winding in the embodiment of the present invention.

[0014] Herein, the reference numerals in the accompanying drawings of the present invention are: Figure-8 shaped magnetic conductive core: 11, A-phase core limb; 12, B-phase core limb; 13, C-phase core limb; 21, Insulating bobbin; 22, Annular partition plate; 23, Lower layer region; 24, Upper layer region; 31, Jumper wire; 41, Clamping structural member; 51, Metal packaging housing; Input busbar assembly: 61, A-phase input terminal; 62, B-phase input terminal; 63, C-phase input terminal; Output busbar assembly: 71, A-phase output terminal; 72, B-phase output terminal; 73, C-phase output terminal. Detailed Description of the Embodiments

[0015] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without making creative work shall fall within the protection scope of the present invention.

[0016] Referring to Figures 1-7 shown, which is an embodiment of the present invention, the provided 12-pulse filter phase shifter between LIT lines will be described in detail below: Referring to Figures 1-2 shown, a 12-pulse filter phase shifter between LIT lines includes: Figure-8 shaped magnetic conductive core, referring to Figures 3-4 shown, this core belongs to the three-phase three-limb core structure in the prior art, which is composed of an upper yoke, a lower yoke, and the A-phase core limb 11, B-phase core limb 12 and C-phase core limb 13 vertically connected therebetween. The three limbs are connected with the upper yoke and the lower yoke to form a complete closed figure-8 shaped magnetic conductive frame, which provides a closed loop with low magnetic reluctance for magnetic flux.

[0017] The core is made of multiple layers of oriented silicon steel sheets stacked horizontally, which is a conventional practice in existing AC electromagnetic devices. The interlayer insulation of the silicon steel sheets is used to cut off eddy current paths and reduce iron losses. The thickness of a single layer of silicon steel sheet can be 0.23mm, 0.27mm, or 0.30mm, depending on the design power and operating frequency. After the silicon steel sheets are stacked to the designed thickness, they are fixed by binding with epoxy resin tape or clamping with steel plates. The cross-section of each core column is rectangular or multi-step. The latter is to maximize the effective cross-sectional area of ​​the core while maintaining the rectangular coil window, which is a conventional design for core cross-sections in existing technology.

[0018] In the normal symmetrical operating state of this embodiment, the combined magnetomotive force of the windings on each core column cancels each other out, and only a small amount of leakage flux exists in the core. Therefore, the effective cross-sectional area of ​​the core column can be significantly smaller than the cross-sectional area of ​​the core of a conventional isolation transformer of the same power rating. This feature is not achieved through a special structure of the core itself, but is determined by the specific winding and connection method of the windings, which will be explained in detail later.

[0019] See Figures 4-5 As shown, the three insulating frames 21 are respectively fitted on the A-phase core column 11, the B-phase core column 12 and the C-phase core column 13. The insulating frames 21 can be made of insulating materials such as epoxy resin or DMC (dense molding compound), and are integrally formed by casting or injection molding. They are common materials and processes for insulating frames 21 of dry-type transformers in the prior art.

[0020] See Figure 5 As shown, an annular partition 22 is integrally formed in the middle of the outer peripheral surface of each insulating frame 21. The annular partition 22 protrudes outward in the radial direction, dividing the winding area of ​​the insulating frame 21 into an independent lower layer area 23 and an upper layer area 24 along the axial direction. The annular partition 22 and the insulating frame 21 body are an integral structure with sufficient mechanical strength and insulation performance to bear the axial stress at the winding end and provide reliable electrical isolation between the upper and lower winding layers.

[0021] See Figures 3-6 As shown, the lower windings are wound within the lower section 23 of each insulating frame 21. Each phase's lower winding consists of a long coil and a short coil connected in series. Taking the lower winding of phase A as an example: (See...) Figure 6 As shown (from right to left in the figure, phases A, B, and C are respectively), the long coil is wound in the lower layer 23 of the insulating frame 21 of the core column 11 of phase A. Its end is connected to the lower layer 23 of the insulating frame 21 of phase B through a jumper wire 31, which runs along the first side space of the core column (defined as the front side in this embodiment, i.e. the side facing the reader) and is connected to the starting end of the short coil wound in this area. The connection method of the lower windings of phase B and phase C is similar, forming a clockwise jumper transmission chain.

[0022] See Figures 3-5 and Figure 7 As shown, the upper winding is wound within the upper region 24 of each insulating frame 21. Each phase's upper winding also consists of a long coil and a short coil connected in series, the opposite of the lower winding. (See reference...) Figure 7 As shown (from left to right in the figure, phases A, B, and C are respectively), the long coil of the upper winding of phase A is wound on the upper region 24 of the insulating frame 21 of phase A core column 11. Its end is connected to the upper region 24 of the insulating frame 21 of phase C core column 13 through the bridging wire 31, and runs along the second side space (defined as the rear side in this embodiment) opposite to the first side of the core column. It is connected to the starting end of the short coil wound in this region. The connection method of the upper windings of phase C and phase B is similar, forming a counterclockwise bridging transmission chain.

[0023] The specific crossover relationships described above can be summarized as follows: (See reference) Figure 6 and Figure 7 As shown, in the lower winding, the end of the long coil of phase A is connected to the starting end of the short coil of phase B core post 12, the end of the long coil of phase B is connected to the starting end of the short coil of phase C core post 13, and the end of the long coil of phase C is connected to the starting end of the short coil of phase A core post 11; in the upper winding, the end of the long coil of phase A is connected to the starting end of the short coil of phase C core post 13, the end of the long coil of phase C is connected to the starting end of the short coil of phase B core post 12, and the end of the long coil of phase B is connected to the starting end of the short coil of phase A core post 11.

[0024] Therefore, all the bridging wires 31 of the lower winding are arranged in the front space of the core column, and all the bridging wires 31 of the upper winding are arranged in the rear space of the core column. The bridging wires 31 of the upper and lower layers are completely separated in space, avoiding cross interference and facilitating assembly and maintenance.

[0025] In this embodiment, the ratio of the number of turns of the short coil Wb to the number of turns of the long coil Wa is: Wb / Wa=0.366, and the total number of turns (the winding to which the output voltage is applied) is: Wab=Wa+Wb=1.366. This turns ratio is a design parameter calculated based on the principle of phase shifting through zigzag wiring. Its derivation process is common knowledge in the field. By controlling the ratio of the number of turns of the long and short coils, the amplitude of both sets of output voltages is made to be basically equal to the amplitude of the input voltage.

[0026] It should be noted that, in order to achieve the output of 12-pulse voltage of the LIT line-to-line filter phase shifter and reduce system manufacturing costs and floor space, this embodiment innovatively designs a conventional 12-pulse rectifier transformer (D / y0d11 combination) as a LIT line-to-line 12-pulse filter phase shifter. The aforementioned zigzag connection refers to each phase winding being wound with two half-windings on different iron core columns, and then connected in reverse series (or in forward series) to obtain phase shift. For the autotransformer method, the input and output share a portion of the winding without isolation. Wab, Wa, Wb: the number of turns of the three windings (corresponding to the two parts on the same phase).

[0027] To ensure electrical safety between windings and between windings and ground, this embodiment features a multi-layered insulation structure. Unless otherwise specified, the insulation materials and processes described below are all existing technologies in the field of transformer manufacturing.

[0028] Inter-segment insulation: In each winding layer, multiple layers of insulating paper or insulating composite film are placed between the long and short coils, such as Nomex insulating paper, DMD composite paper (polyester film-polyester fiber nonwoven fabric-polyester film three-layer composite) or polyimide film. These materials have high dielectric strength and good heat resistance, which are sufficient to withstand the inter-segment voltage within the same winding.

[0029] Interlayer main insulation: After the lower winding is wound, multiple layers of insulating crepe paper are wrapped on top of it, and a pre-formed epoxy resin insulating end ring is placed. Then, the upper winding is wound. This insulating end ring and the annular partition 22 of the insulating frame 21 together form the interlayer main insulation barrier, which withstands the voltage difference between the two sets of output windings. The axial thickness of the annular partition 22 and the number of insulating paper layers are designed according to the maximum possible voltage difference between the two sets of outputs, with sufficient safety margin.

[0030] Insulation to ground: The insulating frame 21 itself provides the main insulation between the winding and the core column. The frame wall thickness is determined according to the working voltage level, and the material itself has sufficient creepage distance and electrical clearance.

[0031] The insulation materials and processes described above are all conventional choices in the field, and this embodiment does not impose any specific limitations on them. Those skilled in the art can select appropriate insulation solutions based on the actual voltage level and heat dissipation requirements.

[0032] See Figure 3 As shown, the filter phase shifter in this embodiment also includes a clamping structure 41 installed at the upper and lower ends of the core. The clamping structure 41 is used to clamp and fix the entire core, providing structural strength and overall rigidity to the core. This is a known prior art and will not be described in detail here.

[0033] See Figure 1 and Figure 2As shown, this embodiment also includes a metal enclosure 51, which houses the aforementioned iron core, insulating frame 21, windings, and clamping structure 41. Specifically, the clamping structure 41 clamps the aforementioned iron core, while the insulating frame 21 and windings are located outside the iron core and are fixed inside the metal enclosure 51 by the clamping structure 41. This installation method is existing known technology and will not be described in detail here. The metal enclosure 51 can be made of cast aluminum or welded steel plate, and has the functions of dustproof, moisture-proof, and electromagnetic shielding. Fins (not shown in the figure) can also be provided on the outer surface of the enclosure to increase the contact area with ambient air.

[0034] See Figures 1-4 As shown, this embodiment also includes an input busbar assembly and an output busbar assembly. The input busbar assembly is fixed to the first sidewall of the metal enclosure 51 and includes an A-phase input terminal 61, a B-phase input terminal 62, and a C-phase input terminal 63, which are arranged side by side in space, with sufficient electrical clearance between the terminals. The output busbar assembly is fixed to the second sidewall of the metal enclosure 51 opposite to the first sidewall, and is divided into a first output group and a second output group, arranged in two rows on the second sidewall. The first output group corresponds to the +15° phase shift output of the lower winding, and the second output group corresponds to the -15° phase shift output of the upper winding. Each group includes an A-phase output terminal 71, a B-phase output terminal 72, and a C-phase output terminal 73.

[0035] Regarding internal wiring: the short coil ends of the lower windings of each phase are led out and connected to the corresponding phase output terminals of the first output group (i.e., the short coil end of phase A is connected to phase A output terminal 71, and the same applies to phases B and C); the short coil ends of the upper windings of each phase are led out and connected to the corresponding phase output terminals of the second output group. The input busbar assembly is connected to the starting ends of the long coils of each phase winding via leads. All the above connections are secured with bolts or cold-pressed terminals, requiring no welding, facilitating assembly and maintenance.

[0036] Working process and function implementation Under normal symmetrical load conditions, the external three-phase AC power supply is connected to this filter phase shifter via the input busbar assembly. The A-phase input terminal 61, B-phase input terminal 62 and C-phase input terminal 63 are respectively connected to the starting end of the long coil of each phase winding. After the input voltage is applied to each phase long coil, since the lower winding and the upper winding adopt a cross-connection transmission chain with opposite directions, the voltage vector is distributed and resynthesized on the winding series path.

[0037] Specifically, in the lower winding, the voltage vector of the long coil of phase A is superimposed with the voltage vector of the short coil of phase B, the long coil of phase B is superimposed with the short coil of phase C, and the long coil of phase C is superimposed with the short coil of phase A, forming a clockwise phase-to-phase voltage vector synthesis path. This causes the output voltage of each phase of the lower winding to have a +15° phase shift relative to the input voltage. In the upper winding, due to the opposite bridging direction, the long coil of phase A is superimposed with the short coil of phase C, the long coil of phase C is superimposed with the short coil of phase B, and the long coil of phase B is superimposed with the short coil of phase A, forming a counterclockwise phase-to-phase voltage vector synthesis path. This causes the output voltage of each phase of the upper winding to have a -15° phase shift relative to the input voltage. Thus, a 30° phase difference is formed between the voltage vectors of the two sets of output windings.

[0038] Let the effective value of the input line voltage be U1, the effective value of the line voltage of the first output group (lower winding) be U2, and the effective value of the line voltage of the second output group (upper winding) be U3. In this invention, the ratio of the number of turns of the short coil Wb to the number of turns of the long coil Wa is set as follows: Wb / Wa=0.366 The total number of turns (the sum of the number of turns of the winding connected in series with the output voltage) is: Wab = Wa + Wb = 1.366 At the aforementioned turns ratio, for the autotransformer with zigzag connection, the effective values ​​of both output line voltages are essentially equal to the effective values ​​of the input line voltages, i.e.: U2=U1, U3=U1 That is, the amplitudes of the two sets of output voltages remain unchanged, only the phases shift by +15° and -15° respectively, with a phase difference of 30°.

[0039] Regarding current distribution, due to the 30° phase difference between the output voltages of the lower and upper windings, according to the magnetomotive force balance principle, the vector sum of the two output currents equals the input current. When the loads connected to the two outputs are symmetrical, let the effective value of the input phase current be I1, the effective value of the first output phase current be I2, and the effective value of the second output phase current be I3. Since the amplitudes of I2 and I3 are equal and the phase difference between them is 30°, their vector sum amplitude is: |I² + I³| = 2 × I² × cos(15°) = I¹ Therefore, the relationship between the effective value of the output phase current and the effective value of the input phase current for each group can be obtained as follows: I2=I3=I1 / (2×cos15°)≈0.52×I1 As can be seen from the voltage and current relationship above, under symmetrical load conditions, this filter phase shifter shifts the input three-phase AC voltage by +15° and -15° respectively through the opposite bridging direction of the lower winding and the upper winding. It outputs two sets of three-phase AC voltages with equal amplitude and a phase difference of 30° from the first output group and the second output group, providing the required power to the subsequent 12-pulse rectifier.

[0040] At this point, the magnetomotive forces generated by the long and short coils of different phases on the same core column cancel each other out. There is almost no main magnetic flux inside the H-shaped magnetic core. The entire device mainly transmits the energy required for phase shifting by means of leakage magnetic field. Therefore, the voltage drop inside the winding is extremely low, the transmission efficiency is higher than 98.5%, and the structural capacity is much smaller than that of conventional isolation transformers of the same power level.

[0041] When the loads connected to the six outputs are unbalanced or the downstream rectifier fails, the combined magnetomotive force on each core column of the iron core is no longer zero, and the main magnetic flux is generated in the H-shaped magnetic core. The iron core exhibits high impedance characteristics, which can effectively limit the short-circuit fault current and protect the system safety.

[0042] Through the above structure and working method, this embodiment realizes the 12-pulse phase shift function, which has the advantages of small size, light weight, high efficiency and maintenance-free operation, filling the gap between line-to-line transformer (LIT) and 12-pulse rectifier integration.

[0043] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0044] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A 12-pulse filter phase shifter between LIT lines, characterized in that, comprising: a Japanese-shape magnetically conductive core, which has an upper iron yoke, a lower iron yoke, and an A-phase core leg (11), a B-phase core leg (12) and a C-phase core leg (13) vertically connected between the upper iron yoke and the lower iron yoke; three insulating bobbins (21), which are sleeved on the three core legs in a one-to-one correspondence, wherein the middle part of each insulating bobbin (21) is fixedly connected with an annular partition plate (22), which is used for dividing the winding area of the insulating bobbin (21) into a lower layer region (23) and an upper layer region (24); a lower layer winding, which is wound in each lower layer region (23), wherein each phase comprises a section of long coil wound in the lower layer region (23) of the insulating bobbin (21) of the core leg of the own phase, and a section of short coil connected to the lower layer region (23) of the insulating bobbin (21) of the core leg of another phase through a jumper fly line (31), the tail end of the long coil is electrically connected with the starting end of the short coil, and all the jumper fly lines (31) of the lower layer winding are arranged in the first side space of the core legs; an upper layer winding, which is wound in each upper layer region (24), wherein each phase comprises a section of long coil wound in the upper layer region (24) of the insulating bobbin (21) of the core leg of the own phase, and a section of short coil connected to the upper layer region (24) of the insulating bobbin (21) of the core leg of another phase through a jumper fly line (31), the tail end of the long coil is electrically connected with the starting end of the short coil, and all the jumper fly lines (31) of the upper layer winding are arranged in the second side space of the core legs opposite to the first side of the core legs; wherein, the transmission direction of the target core legs connected by all the jumper fly lines (31) of the lower layer winding is opposite to that of the target core legs connected by all the jumper fly lines (31) of the upper layer winding in the arrangement sequence of the three-phase core legs; clamping structural members (41), which are fixedly installed at the upper end and the lower end of the Japanese-shape magnetically conductive core, wherein a sealed cavity (42) is arranged inside each clamping structural member (41) and filled with a phase-change heat storage material, one side of the clamping structural member (41) is in close contact with the winding ends and the iron yokes through an insulating heat conduction layer, and the other side is provided with heat dissipation fins (43); a metal packaging shell (51), which accommodates the Japanese-shape magnetically conductive core, the insulating bobbins (21), the windings and the clamping structural members (41), wherein a heat conduction path is established between the heat dissipation fins (43) of the clamping structural member (41) and the inner wall of the metal packaging shell (51).

2. The LIT line-to-line 12-pulse filter phase shifter according to claim 1, characterized in that: In the lower layer winding, the tail end of the long coil of phase A is jumpered to the starting end of the short coil of the B-phase core leg (12), the tail end of the long coil of phase B is jumpered to the starting end of the short coil of the C-phase core leg (13), and the tail end of the long coil of phase C is jumpered to the starting end of the short coil of the A-phase core leg (11); In the upper layer winding, the tail end of the long coil of phase A is jumpered to the starting end of the short coil of the C-phase core leg (13), the tail end of the long coil of phase C is jumpered to the starting end of the short coil of the B-phase core leg (12), and the tail end of the long coil of phase B is jumpered to the starting end of the short coil of the A-phase core leg (11).

3. A 12-pulse filter phase shifter between LIT lines according to claim 1, characterized in that: The ratio of the number of turns of the short coil to the number of turns of the long coil is 0.

366.

4. A 12-pulse filter phase shifter between LIT lines according to claim 1, characterized in that: In the lower layer region (23), the short coil is arranged close to the annular partition plate (22), and the long coil is arranged away from the annular partition plate (22); In the upper region (24), the short coil is set close to the annular partition (22), and the long coil is set away from the annular partition (22), so that the short coil in the lower region (23) and the short coil in the upper region (24) are symmetrically arranged on both sides of the annular partition (22).

5. A 12-pulse filter phase shifter between LIT lines according to claim 1, characterized in that: It also includes an input busbar assembly and an output busbar assembly. The input busbar assembly is disposed on the first side wall of the metal encapsulation housing (51) and includes an A-phase input terminal (61), a B-phase input terminal (62) and a C-phase input terminal (63). The output busbar assembly is disposed on the second side wall of the metal encapsulation housing (51) and is divided into a first output group and a second output group. Each group includes an A-phase output terminal (71), a B-phase output terminal (72) and a C-phase output terminal (73). The ends of the lower windings of each phase are respectively connected to the corresponding phase output terminals of the first output group, and the ends of the upper windings of each phase are respectively connected to the corresponding phase output terminals of the second output group.

6. A 12-pulse filter phase shifter between LIT lines according to claim 1, characterized in that: The solid-liquid phase change temperature of phase change thermal storage materials is lower than the withstand temperature of the insulation material of the winding.

7. A 12-pulse filter phase shifter between LIT lines according to claim 1, characterized in that: The inner wall of the metal encapsulation housing (51) is provided with a heat conduction groove (52) that is inserted and matched with the heat dissipation fins (43) of the clamping structure (41). After assembly, the heat dissipation fins (43) are embedded in the heat conduction groove (52) to establish a heat conduction path.

8. A 12-pulse filter phase shifter between LIT lines according to claim 1, characterized in that: The heat dissipation fins (43) of the clamping structure (41) and the inner wall of the metal encapsulation shell (51) are filled with a thermally conductive interface material to establish a heat conduction path.

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