Twelve-pulse self-coupling phase-shifting rectifier transformer for high voltage

Abstract

The twelve-pulse self-coupling phase-shifting rectifier transformer comprises an iron core and an A-phase winding, a B-phase winding and a C-phase winding which are wound on the iron core, each phase winding is composed of a primary input side winding and a secondary output side winding, and the primary input side windings (AA 'X, BB' Y and CC 'Z) are composed of basic windings (A' X, B 'Y and CC' Z); b 'Y; c 'Z) and a series winding (AA'; bB '; the secondary output side windings (a1A 'X and a2A' X, b1B 'Y and b2B' Y, and c1C 'Z and c2C' Z) are composed of a basic winding and two phase shift windings (c1C 'and b2B'; a1A'and c2Z '; the A phase is provided with two secondary windings, the angle between the two secondary windings is 30 degrees, the corresponding included angle between the B phase and the C phase is consistent with that of the A phase, the windings are wound with one of three sequences of series winding-basic winding-phase shifting winding, basic winding-series winding-phase shifting winding and free combination by throwing out an output side lead outlet head, and the output side lead outlet head can be used for free combination of the series winding-basic winding-phase shifting winding, the basic winding-series winding-phase shifting winding and the basic winding-series winding-phase shifting winding and the output side lead outlet head. After rectification, the transformer can reduce harmonic content and improve power supply quality.

Description

Technical Field

[0001] This article belongs to the technical field of power equipment, and also involves power supply-related technical fields such as 750 kV and above AC transmission, large-scale power grid security and defense system and intelligent dispatch system. Specifically, it is a twelve-pulse autotransformer for high voltage. Background Technology

[0002] As modern power systems develop towards higher voltage, larger capacity, and greater intelligence, the requirements for power quality, system efficiency, and operational reliability are increasing. In particular, in critical power supply scenarios such as high voltage, efficient and reliable power conversion and supply equipment plays an indispensable core role.

[0003] As a key component of rectifier equipment, rectifier transformers have a wide and irreplaceable application in many industrial fields that require DC power, such as electrochemistry, electrolysis, electroplating, DC drives, and DC power transmission. Their core function is to transform the AC voltage of the power grid to adapt it to the working requirements of the rectifier circuit. Then, with the help of rectifier components such as diodes and thyristors, the AC to DC power conversion is completed. When a three-phase transformer adopts the bridge rectification method, a six-pulse transformer with six peaks can be obtained. However, if more pulses are desired, phase shifting must be used. As the number of pulses increases, the DC voltage and current waveforms of the rectified output will be closer to the ideal flat state. Moreover, multi-pulse rectifier transformers can effectively suppress multiple harmonics and reduce pollution to the power grid, which is of great significance for maintaining the clean and stable operation of the power grid.

[0004] Figure (1) shows a three-phase autotransformer. An autotransformer is a transformer with a special structure. Its significant feature is that the primary and secondary windings share the same set of coils, which is different from the structure of the primary and secondary windings being independent in the traditional two-winding transformer. By drawing different taps (i.e. connection points with different numbers of turns) from this shared winding, the input voltage and output voltage can be flexibly transformed, including step-up or step-down operations. Compared with a two-winding transformer, an autotransformer has many advantages because it eliminates a set of independent windings: on the one hand, it saves a lot of materials and reduces production costs; on the other hand, it improves the efficiency of energy transmission and reduces the size of the equipment. These advantages make autotransformers have a good application prospect in the power system and can better meet the requirements of high performance, high economy and compactness of equipment in power supply scenarios such as high-voltage AC transmission, providing strong equipment support for the safety guarantee and intelligent dispatch of large-scale power grids.

[0005] Therefore, in key power supply scenarios such as 750 kV and above AC transmission, large-scale power grid security and defense systems, and intelligent dispatching systems, further optimizing the performance of autotransformers to enable them to work better with rectifier transformers and other equipment, so as to accurately meet the complex requirements of multi-pulse rectification for voltage transformation accuracy, harmonic suppression effect and equipment compatibility, and thus ensure the stability and economy of high-voltage and large-scale power grid operation, remains a core issue that needs to be studied in depth by those skilled in the art. Summary of the Invention

[0006] To address the aforementioned problems, this paper proposes a twelve-pulse autotransformer phase-shifting rectifier for high voltage, comprising an iron core and three-phase windings (phase A, phase B, and phase C) wound on the iron core. The key feature is that each phase winding consists of a primary input winding and a secondary output winding. The primary input windings are identified as AA'X, BB'Y, and CC'Z, respectively, while the secondary output windings are identified as a1A'X and a2A'X, b1B'Y and b2B'Y, and c1C'Z and c2C'Z, respectively. The primary input winding consists of a basic winding and a series winding, with the basic windings identified as A'X, B'Y, and... C'Z, the series windings are identified as A'A, B'B, and C'C respectively. The secondary output winding consists of a basic winding and two phase-shifting windings. The two phase-shifting windings are phase-shifting winding one and phase-shifting winding two. Phase-shifting winding one is identified as A'a1, B'b1, and C'c1 respectively, and phase-shifting winding two is identified as A'a2, B'b2, and C'c2 respectively. Two secondary windings are provided on phase A, namely c1C'Z and b2B'Y. The angle between the two secondary windings and AA'X is 15°, and the angle between c1C'Z and b2B'Y is 30°. °, the angles between the two secondary windings in phase B and BB'Y, and the angles between the two secondary windings in phase C and CC'Z, are consistent with those in phase A. There are three winding sequences: series winding – basic winding – phase-shifting winding; basic winding – series winding – phase-shifting winding; and a sequence where, excluding the output lead, the series winding, basic winding, and phase-shifting winding can be freely combined. One of these three sequences is used during winding. This structure consists of a primary input winding composed of a basic winding and a series winding, and a secondary output winding configured with a basic winding and two phase-shifting windings. Combined with specific angle settings and winding combination methods, it can effectively achieve… The twelve-pulse rectifier has two secondary windings, c1C'Z and b2B'Y, with both windings angled at 15° to AA'X. The angles between phases B and C are the same as those between phase A. This 15° angle difference significantly reduces harmonic components during rectification, making it particularly suitable for high-voltage AC transmission systems. It can effectively support the construction of large-scale power grid security and defense systems, and improve the stability and reliability of power supply under intelligent dispatching systems. Furthermore, the flexible selection of three winding sequences allows the transformer to be adapted to different installation environments and usage scenarios, enhancing its versatility and practicality.

[0007] The twelve-pulse autotransformer phase-shifting rectifier transformer uses an autotransformer as its base and a zigzag phase-shifting method to boost a six-pulse wave to a twelve-pulse wave. Through the design of the autotransformer structure, it can effectively reduce the amount of materials used, reduce the size and weight of the equipment, and improve power transmission efficiency. At the same time, by adopting a zigzag phase-shifting method, waveform superposition is achieved by utilizing the phase difference between the windings, which greatly reduces the DC voltage ripple coefficient of the rectified output. This is of great significance for industrial fields that require stable DC power supplies.

[0008] The core is made of high-quality, high-permeability silicon steel sheets, formed through a multi-stage step-laminated lamination process. This process, combined with the insulating coating design between the silicon steel sheets, can significantly reduce hysteresis loss and eddy current loss, improve magnetic permeability and mechanical strength, and ensure that the core maintains a low loss level under high-frequency alternating magnetic fields. At the same time, the multi-stage step-laminated structure makes the magnetic flux distribution more uniform, effectively avoiding the heating problem caused by excessive local magnetic flux density, thereby improving the transformer's operational stability and service life, and making it especially suitable for industrial environments with long-term continuous operation.

[0009] All three phases are rectified by a rectifier to obtain a 360° / (2×15°) = twelve-pulse power supply. This rectification method combines two sets of three-phase bridge rectifier circuits with a specific phase difference, which greatly reduces the harmonic content of the AC input current. At the same time, the DC voltage ripple coefficient of the twelve-pulse rectified output is significantly reduced, providing a more stable DC power supply for the subsequent load.

[0010] The winding sequence of series winding – basic winding – phase-shifting winding is as follows: series winding, basic winding, phase-shifting winding one, and phase-shifting winding two. The winding sequence of all three phases is the same. This standardized winding sequence design can ensure that the spatial layout of each winding on the iron core is more reasonable, effectively reducing electromagnetic interference between windings. At the same time, the unified three-phase winding sequence facilitates automated winding operations in the production process, improving the overall consistency and reliability of the transformer.

[0011] The winding sequence of the series winding, the basic winding, and the phase-shifting winding is consistent with the winding arrangement sequence. The series winding is arranged near the innermost part of the iron core, the basic winding is close to the outermost part of the series winding, and the phase-shifting winding is located on the outermost part of the entire structure. Through this concentric arrangement from the inside out, the distance between each winding and the iron core, as well as the insulation distance between the windings, can be precisely controlled. This ensures the magnetic coupling efficiency of the iron core to each winding and further reduces leakage magnetic interference between different windings through reasonable separation of physical space.

[0012] The series winding, the basic winding, and the phase-shifting winding are all made of copper wire. Copper wire has high conductivity, which can effectively reduce resistance loss when current passes through and improve the power transmission efficiency of the winding. At the same time, the selection of copper wire also takes into account its excellent anti-oxidation properties, which can slow down the oxidation rate of the winding in transformer oil or air and extend the service life of the transformer.

[0013] Beneficial effects:

[0014] The primary input winding consists of a basic winding and a series winding, while the secondary output winding is configured with a basic winding and two phase-shifting windings. Combined with specific angle settings and winding combinations, this system effectively achieves twelve-pulse rectification. The two secondary windings are c1C'Z and b2B'Y, with both windings angled at 15° relative to AA'X. The angles between phases B and C are consistent with phase A. This 15° angle difference significantly reduces harmonic components during rectification, making it particularly suitable for high-voltage AC transmission systems. It effectively supports the construction of large-scale power grid security and defense systems, improving the stability and reliability of power supply under intelligent dispatching systems. Furthermore, the flexible selection of three winding sequences allows the transformer to be adapted to different installation environments and usage scenarios, enhancing its versatility and practicality.

[0015] The design of the autotransformer structure can effectively reduce the amount of materials used, reduce the size and weight of the equipment, and improve the power transmission efficiency. At the same time, by adopting a tortuous phase shift method, the waveform superposition is achieved by utilizing the phase difference between the windings, which greatly reduces the DC voltage ripple coefficient of the rectified output. This is of great significance for industrial fields that require stable DC power supplies.

[0016] By using high-quality, high-permeability silicon steel sheets for the core, and employing a multi-stage step-laminated lamination process combined with an insulating coating design between the silicon steel sheets, hysteresis loss and eddy current loss can be significantly reduced, while improving magnetic permeability and mechanical strength. This ensures that the core maintains a low loss level under high-frequency alternating magnetic fields. At the same time, the multi-stage step-laminated structure makes the magnetic flux distribution more uniform, effectively avoiding the heating problem caused by excessive local magnetic flux density, thereby improving the transformer's operational stability and service life. It is especially suitable for industrial environments with long-term continuous operation.

[0017] By rectifying all three phases through a rectifier to obtain a 360° / (2×15°) = twelve-pulse power supply rectification method, two sets of three-phase bridge rectifier circuits are combined with a specific phase difference, which can significantly reduce the harmonic content of the AC input current. At the same time, the DC voltage ripple coefficient of the twelve-pulse rectified output is significantly reduced, providing a more stable DC power supply for subsequent loads.

[0018] By designing a standardized winding sequence, it is possible to ensure a more reasonable spatial layout of each winding on the core, effectively reducing electromagnetic interference between windings. At the same time, a unified three-phase winding sequence facilitates automated winding operations during the production process, improving the overall consistency and reliability of the transformer.

[0019] By using a concentric winding arrangement from the inside out, the distance between each winding and the iron core, as well as the insulation distance between the windings, can be precisely controlled. This ensures the magnetic coupling efficiency of the iron core to each winding, and further reduces leakage magnetic interference between different windings through reasonable physical space separation.

[0020] By using copper wire for winding, the high conductivity of copper wire can effectively reduce resistance loss when current passes through, improve the power transmission efficiency of the winding, and the selection of copper wire also takes into account its excellent anti-oxidation properties, which can slow down the oxidation rate of the winding in transformer oil or air and extend the service life of the transformer. Attached Figure Description

[0021] Figure 1 This is a wiring diagram for a twelve-pulse autotransformer phase-shifting rectifier transformer used in high voltage applications.

[0022] Figure 2 This is a voltage phasor diagram of a twelve-pulse autotransformer phase-shifting rectifier transformer used in high voltage applications.

[0023] Figure 3 This is a schematic diagram of the structural layout of a twelve-pulse autotransformer phase-shifting rectifier transformer used in high voltage applications.

[0024] Figure 4 This is a schematic diagram of an autotransformer. Detailed Implementation

[0025] To enhance understanding of the present invention, the invention will be further described in detail below with reference to embodiments and accompanying drawings. These embodiments are only for explaining the invention and do not constitute a limitation on the scope of protection of the invention.

[0026] Implementation example;

[0027] 1. For example Figure 4As shown, the winding sequence adopts the winding order of series winding - basic winding - phase-shifting winding. After the winding is assembled, lead wire connection is required. First, the starting ends (A, B, C) of the series winding are led to the input side bushing through lead wires and connected to the ending ends of the series winding, which is the starting ends (A', B', C') of the basic winding. Then, the ending ends (X, Y, Z) of the basic winding are connected together through lead wires to complete the input side lead wire connection. Then, the starting end (A') of the basic winding of column A is split into two through lead wires and connected to the ending end x1' of phase-shifting winding 1 on column B and the ending end x2' of phase-shifting winding 2 on column C, thus completing the Z-type connection of one phase. The lead wire connection method of the other two phases is the same as that of column A. Finally, the starting ends (a1, a2, b1, b2, c1, c2) of the phase-shifting windings of each of the three columns are led to the corresponding outgoing bushings through lead wires to complete the overall lead wire connection.

[0028] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A twelve-pulse autotransformer phase-shifting rectifier transformer for high voltage, comprising a core and three-phase windings (A-phase, B-phase and C-phase) wound on the core, characterized in that, Each of the phase windings is composed of a primary input side winding and a secondary output side winding, the primary input side winding is marked as AA'X, BB'Y and CC'Z respectively, the secondary output side winding is marked as a1A'X and a2A'X, b1B'Y and b2B'Y and c1C'Z and c2C'Z respectively, the primary input side winding is composed of a basic winding and a series winding, the basic winding is marked as A'X, B'Y and C'Z respectively, the series winding is marked as A'A, B'B and C'C respectively, the secondary output side winding is composed of a basic winding and two-phase phase-shifting windings, the two-phase phase-shifting windings are phase-shifting winding one and phase-shifting winding two respectively, the phase-shifting winding one is marked as a1A', b1B' and c1C' respectively, the phase-shifting winding two is marked as a2A', b2B' and c2C' respectively, two secondary windings are arranged on the A phase, the two secondary windings are c1C'Z and b2B'Y respectively, the angle between the two secondary windings and the primary input side winding AA'X is 15°, the angle between c1C'Z and b2B'Y is 30°, the angle between the two secondary windings and the primary input side winding BB'Y in the B phase and the angle between the two secondary windings and the primary input side winding CC'Z in the C phase are consistent with the angle between the two secondary windings and the primary input side winding AA'X in the A phase, the winding winding sequence has three kinds, which are series winding-basic winding-phase-shifting winding, basic winding-series winding-phase-shifting winding, and the sequence of the output side lead-out head can be freely combined by the series winding, the basic winding and the phase-shifting winding, and one of the three sequences is adopted in the winding process.

2. A twelve pulse self-coupled phase-shifting rectifier transformer for high voltage as claimed in claim 1, wherein, The twelve-pulse self-coupling phase-shifting rectifier transformer is based on a self-coupling transformer and improves six-pulse wave to twelve-pulse wave through a zigzag moving method.

3. A twelve pulse self-coupled phase-shifting rectifier transformer for high voltage as claimed in claim 1, wherein, The iron core is made of high-quality high-permeability silicon steel sheet and is formed through a multi-stage stepping lamination process.

4. A twelve pulse self-coupled phase-shifting rectifier transformer for high voltage as claimed in claim 1, wherein, The three-phase is rectified by a rectifier to obtain a 360° / (2*15°)=twelve-pulse power supply.

5. A twelve pulse self-coupled phase shifting rectifier transformer for high voltage as claimed in claim 1, wherein, The series winding-basic winding-phase-shifting winding winding sequence is series winding, basic winding, phase-shifting winding one and phase-shifting winding two in turn, and the winding sequence of the three phases is the same.

6. A twelve pulse self-coupled phase shifting rectifier transformer for high voltage as claimed in claim 1 wherein, The series winding-basic winding-phase-shifting winding winding sequence is consistent with the winding arrangement sequence, the series winding is arranged at the position close to the innermost side of the iron core, the basic winding is next to the outermost side of the series winding, and the phase-shifting winding is located at the outermost side of the whole structure.

7. A twelve pulse self-coupled phase shifting rectifier transformer for high voltage as claimed in claim 1 wherein, The series winding, the basic winding and the phase-shifting winding are all wound by copper wires.

8. A twelve-pulse autotransformer phase-shifting rectifier transformer for high voltage, characterized by The output side is provided with a lead-out lead-out head, the winding sequence adopts the series winding-basic winding-phase-shifting winding winding sequence, the winding needs to be connected after being sleeved, and the wiring process is as follows: S1, the first end (A, B, C) of the series winding needs to be led to the input side through a lead line, and the first end (A', B', C') of the basic winding is connected together, and then the tail end (X, Y, Z) of the basic winding is connected together to complete the input side lead line connection; S2, the first end (A') of the basic winding of the A column is connected to the tail end x1' of the B column phase shifting winding one and the tail end x2' of the C column phase shifting winding two through lead wire, and then the Z type connection of one phase is completed, and the lead wire connection mode of the remaining two phases is the same as that of the A column; S3, the first end (a1, a2, b1, b2, c1, c2) of the phase shifting winding of each column is led to the corresponding outlet bushing through the lead wire, and the overall lead wire connection is completed.

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