Three-phase-to-single-phase alternating-current transformer, transformation device and railway power transmission system

Abstract

The invention relates to a three-phase-to-single-phase alternating-current transformer, a transformation device and a railway power transmission system. A first primary winding in the transformer comprises an A-phase primary winding, a B-phase primary winding and a C-phase primary winding, the first end of each phase of primary winding is correspondingly connected with single-phase alternating current, and the first ends of the phase of primary windings are mutually connected to form a neutral point; the first secondary winding comprises an A-phase secondary winding, a B-phase secondary winding and a C-phase secondary winding, the A-phase secondary winding is connected with the second primary winding, the first end of the B-phase secondary winding is connected with the first end of the C-phase secondary winding to form a neutral point, and the second end of the B-phase secondary winding and the second end of the C-phase secondary winding are jointly connected to the third primary winding; the first end of each phase of secondary winding and the first end of the corresponding phase of primary winding are dotted terminals; the second secondary winding is coupled with the second primary winding and the third primary winding. By adopting the transformer, the conversion from three-phase alternating current to single-phase alternating current can be efficiently realized.

Description

Technical Field

[0001] The present application relates to the technical field of transformers, and in particular to a three-phase to single-phase AC transformer, a transformer device and a railway power transmission system. Background Art

[0002] In modern railway transportation systems, especially in the field of high-speed railways (HSR), single-phase AC is usually used as the traction power supply standard. In order to ensure the safety and stability of power supply, the power supply network is divided into multiple electrically isolated sections, each of which is powered by an independent power supply point. These power supply points are generally connected to the main power grid through high-voltage transmission lines, and the high-voltage three-phase AC is converted into single-phase AC suitable for railway traction through voltage conversion equipment.

[0003] However, the traditional three-phase rectification and inverter output single-phase technical solutions have obvious limitations. For example, the frequent on and off operations of power electronic devices such as thyristors involved in the single-phase output process will not only generate a large amount of electromagnetic interference, but may also cause instantaneous sparking of the contact network and arcing when the pantograph power point is switched, thereby causing non-power frequency interference to the power grid, affecting its stable operation, and may even trigger malfunctions of the power system. Secondly, due to the low energy conversion efficiency in the inverter process, the system will be accompanied by large heat losses during operation, which will increase operating costs and have an adverse impact on the environment. Summary of the invention

[0004] Based on this, it is necessary to provide a three-phase to single-phase AC transformer, a transformer device and a railway power transmission system.

[0005] In a first aspect, the present application provides a three-phase to single-phase AC transformer, the transformer comprising: a first primary winding, a first secondary winding, a second primary winding, a third primary winding and a second secondary winding;

[0006] The first primary winding includes an A-phase primary winding, a B-phase primary winding, and a C-phase primary winding, wherein the first end of the A-phase primary winding is used to connect to the A-phase alternating current, the first end of the B-phase primary winding is used to connect to the B-phase alternating current, and the first end of the C-phase primary winding is used to connect to the C-phase alternating current, and the second end of the A-phase primary winding, the second end of the B-phase primary winding, and the second end of the C-phase primary winding are connected to each other to form a neutral point;

[0007] The first secondary winding includes an A-phase secondary winding, a B-phase secondary winding, and a C-phase secondary winding, wherein the first end of the A-phase secondary winding is connected to the first end of the second primary winding, the second end of the A-phase secondary winding is connected to the second end of the second primary winding, the first end of the B-phase secondary winding is connected to the first end of the C-phase secondary winding to form a neutral point, the second end of the B-phase secondary winding is connected to the first end of the third primary winding, the second end of the C-phase secondary winding is connected to the second end of the third primary winding, the first end of the A-phase secondary winding and the first end of the A-phase primary winding are the same end, the first end of the B-phase secondary winding and the first end of the B-phase primary winding are the same end, and the first end of the C-phase secondary winding and the first end of the C-phase primary winding are the same end;

[0008] The second secondary winding is coupled to the second primary winding and the third primary winding.

[0009] In one embodiment, the number of turns of the A-phase primary winding, the B-phase primary winding and the C-phase primary winding are the same.

[0010] In one embodiment, the number of turns of the A-phase secondary winding is the same as the number of turns of the A-phase primary winding, the number of turns of the B-phase secondary winding is the same as the number of turns of the B-phase primary winding, and the number of turns of the C-phase secondary winding is the same as the number of turns of the C-phase primary winding.

[0011] In one embodiment, the number of turns of the second primary winding is the same as the number of turns of the A-phase secondary winding.

[0012] In one embodiment, the number of turns of the third primary winding is equal to the number of turns of the A-phase secondary winding. times.

[0013] In one of the embodiments, the transformer further comprises: a three-column core;

[0014] The A-phase primary winding and the A-phase secondary winding are coaxially sleeved on the first core of the three-column core, the B-phase primary winding and the B-phase secondary winding are coaxially sleeved on the second core of the three-column core, and the C-phase primary winding and the C-phase secondary winding are coaxially sleeved on the third core of the three-column core.

[0015] In one of the embodiments, the transformer further comprises: a double-column core;

[0016] The second primary winding and the third primary winding are coaxially sleeved on the first iron core of the double-column iron core, and the second secondary winding is sleeved on the second iron core of the double-column iron core.

[0017] In one embodiment, the number of turns of the second secondary winding is the same as the number of turns of the second primary winding.

[0018] In a second aspect, the present application further provides a transformer device, which includes a three-phase to single-phase AC transformer as in the above embodiment.

[0019] In a third aspect, the present application further provides a railway power transmission system, which includes a transformer as in the above embodiment.

[0020] The above three-phase to single-phase AC transformer, transformer device and railway power transmission system have at least the following beneficial effects:

[0021] The above three-phase to single-phase AC transformer, through the combined use of phase-shifting transformer and isolation coupling transformer, not only effectively changes the phase relationship of the input three-phase AC power, but also synthesizes the three-phase voltage into a single output voltage through a reasonable winding connection strategy, which not only reduces the common electromagnetic interference and heat loss problems in the traditional three-phase rectification and inversion process, improves the overall efficiency of the system, but also simplifies the equipment structure, reduces costs and floor space. At the same time, it improves the reliability of the railway traction power supply system and reduces maintenance costs, and is particularly suitable for application scenarios such as high-speed railways that have high requirements for power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] FIG1 is a schematic structural diagram of a three-phase to single-phase AC transformer in one embodiment;

[0024] FIG2 is a vector diagram of a phase-shifting transformer in one embodiment;

[0025] FIG. 3 is a vector diagram of an isolation coupling transformer in one embodiment. DETAILED DESCRIPTION

[0026] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0028] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0029] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0030] It can be understood that “at least one” means one or more, “plurality” means two or more, and “at least a portion of an element” means a part or all of an element.

[0031] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0032] In an exemplary embodiment, as shown in FIG1 , the present application provides a three-phase to single-phase AC transformer, the transformer comprising: a first primary winding, a first secondary winding, a second primary winding La', a third primary winding Ln and a second secondary winding Lo; wherein the first primary winding comprises an A-phase primary winding LA, a B-phase primary winding LB, and a C-phase primary winding LC, the first end A* of the A-phase primary winding LA is used to access the A-phase AC, the first end B* of the B-phase primary winding LB is used to access the B-phase AC, the first end C* of the C-phase primary winding LC is used to access the C-phase AC, the second end N1 of the A-phase primary winding LA, the second end N2 of the B-phase primary winding LB and the second end N3 of the C-phase primary winding LC are interconnected to form a neutral point N; the first secondary winding comprises an A-phase secondary winding La, a B-phase secondary winding Lb, and a C-phase secondary winding Lc, the A-phase secondary winding La's The first end a* is connected to the first end a* of the second primary winding La', the second end n1 of the A-phase secondary winding La is connected to the second end n of the second primary winding La', the first end b* of the B-phase secondary winding Lb is connected to the first end c* of the C-phase secondary winding Lc to form a neutral point, the second end n2 of the B-phase secondary winding Lb is connected to the first end nb* of the third primary winding Ln, the second end n3 of the C-phase secondary winding Lc is connected to the second end nc* of the third primary winding Ln, the first end a* of the A-phase secondary winding La and the first end A* of the A-phase primary winding LA are the same-named ends, the first end b* of the B-phase secondary winding Lb and the first end B* of the B-phase primary winding LB are the same-named ends, the first end c* of the C-phase secondary winding Lc and the first end C* of the C-phase primary winding LC are the same-named ends; the second secondary winding Lo is coupled to the second primary winding La' and the third primary winding Ln.

[0033] 1 , the first primary winding and the first secondary winding form a phase-shifting transformer to change the phase. The second primary winding La', the third primary winding Ln and the second secondary winding Lo form an isolation coupling transformer to achieve a combined output.

[0034] Among them, the first end A* of the A-phase primary winding LA in the first primary winding is connected to the A-phase alternating current, the first end B* of the B-phase primary winding LB is connected to the B-phase alternating current, and the first end C* of the C-phase primary winding LC is connected to the C-phase alternating current. The second end N1 of the A-phase primary winding LA in the first secondary winding, the second end N2 of the B-phase primary winding LB and the second end N3 of the C-phase primary winding LC are connected to each other to form a neutral point; and the first end b* of the B-phase secondary winding Lb in the first secondary winding is connected to the first end c* of the C-phase secondary winding Lc to form a neutral point. By adopting the same-name terminals connected in parallel as the neutral point, the primary side vector of the phase-shifting transformer is shown as the first vector diagram from left to right in FIG. 2, with The secondary side vector of the phase-shifting transformer is shown as the second vector diagram and the third vector diagram from left to right in FIG2; and the first end a* of the A-phase secondary winding La is connected to the first end a* of the second primary winding La', the second end n1 of the A-phase secondary winding La is connected to the second end n of the second primary winding La', the second end n2 of the B-phase secondary winding Lb is connected to the first end nb* of the third primary winding Ln, and the second end n3 of the C-phase secondary winding Lc is connected to the second end nc* of the third primary winding Ln, and the output is output from the non-same-name end, so that the primary side vector of the isolation coupling transformer is shown as the first vector diagram and the second vector diagram from left to right in FIG3, that is, the phase of Ubc will be consistent with the phase of Ua. Considering the inconsistency of their respective internal impedances, the second secondary winding Lo is coupled with the second primary winding La' and the third primary winding Ln, and two independent windings are introduced into the coupling transformer for output, so that after the vector superposition is realized on the secondary side of the isolation coupling transformer, a single-phase voltage output is synthesized as shown in the third vector diagram from left to right in FIG3.

[0035] The above three-phase to single-phase AC transformer, through the combined use of phase-shifting transformer and isolation coupling transformer, not only effectively changes the phase relationship of the input three-phase AC power, but also synthesizes the three-phase voltage into a single output voltage through a reasonable winding connection strategy, which not only reduces the common electromagnetic interference and heat loss problems in the traditional three-phase rectification and inversion process, improves the overall efficiency of the system, but also simplifies the equipment structure, reduces costs and floor space. At the same time, it improves the reliability of the railway traction power supply system and reduces maintenance costs, and is particularly suitable for application scenarios such as high-speed railways that have high requirements for power supply.

[0036] In an exemplary embodiment, the number of turns of the A-phase primary winding LA, the B-phase primary winding LB, and the C-phase primary winding LC are the same.

[0037] Exemplarily, the number of turns of the A-phase primary winding LA, the B-phase primary winding LB and the C-phase primary winding LC are the same, ensuring that the three-phase input current can be evenly distributed on the primary side of the transformer, thereby ensuring the balance of the three-phase system, helping to reduce the magnetic flux imbalance inside the transformer, reduce core loss and copper loss, and improve the working efficiency and stability of the transformer.

[0038] In an exemplary embodiment, the number of turns of the A-phase secondary winding La is the same as the number of turns of the A-phase primary winding LA, the number of turns of the B-phase secondary winding Lb is the same as the number of turns of the B-phase primary winding LB, and the number of turns of the C-phase secondary winding Lc is the same as the number of turns of the C-phase primary winding LC.

[0039] Exemplarily, the number of turns of the A-phase secondary winding La is the same as the number of turns of the A-phase primary winding LA, the number of turns of the B-phase secondary winding Lb is the same as the number of turns of the B-phase primary winding LB, and the number of turns of the C-phase secondary winding Lc is the same as the number of turns of the C-phase primary winding LC, ensuring that the transformer maintains a 1:1 voltage ratio between each phase, thereby achieving precise phase adjustment and voltage conversion, which not only helps to maintain the stability and purity of the output voltage and reduce voltage distortion, but also ensures the balance of the three-phase system, further reduces the harmonic components and electromagnetic interference in the system, and improves the quality and efficiency of power transmission.

[0040] In an exemplary embodiment, the number of turns of the second primary winding La' is the same as the number of turns of the A-phase secondary winding La.

[0041] Exemplarily, the number of turns of the second primary winding La' is the same as the number of turns of the A-phase secondary winding La in the first secondary winding, ensuring that the voltage ratio from the first secondary winding to the second primary winding La' is 1:1, thereby achieving lossless voltage transfer and phase matching, which not only helps to maintain the stability and purity of the output voltage, reduce power loss and signal distortion caused by inaccurate voltage conversion, but also ensures efficient energy transmission inside the transformer and improves the conversion efficiency of the entire system.

[0042] In an exemplary embodiment, the number of turns of the third primary winding Ln is twice the number of turns of the A-phase secondary winding La. times.

[0043] For example, the amplitude of the voltage Ubc output from the B-phase secondary winding Lb and the C-phase secondary winding Lc in the first secondary winding and formed in the third primary winding Ln is greater than the amplitude of the voltage Ua formed in the second primary winding La'. times, so by adjusting the number of turns of the third primary winding Ln, times, realizing that the three-phase AC voltage with a difference of 120 degrees is adjusted into two voltages of the same amplitude, effectively balancing the three-phase voltage, ensuring the stability and consistency of the output voltage, and reducing voltage fluctuations and phase distortion. At the same time, by reasonably adjusting the number of winding turns, the structure and performance of the transformer are optimized, the energy conversion efficiency is improved, the system complexity and cost are reduced, and the reliability and adaptability of the system are enhanced. It is particularly suitable for applications that require high-quality single-phase output voltage, such as the traction power supply system of high-speed railways.

[0044] In an exemplary embodiment, the transformer further includes: a three-column iron core. The A-phase primary winding LA and the A-phase secondary winding La are coaxially sleeved on the first core of the three-column iron core, the B-phase primary winding LB and the B-phase secondary winding Lb are coaxially sleeved on the second core of the three-column iron core, and the C-phase primary winding LC and the C-phase secondary winding Lc are coaxially sleeved on the third core of the three-column iron core.

[0045] For example, the transformer adopts a three-column iron core structure, and the primary winding and secondary winding of each phase are coaxially sleeved on the corresponding iron core, which can not only effectively reduce inter-phase interference and improve the utilization rate of magnetic flux, but also ensure that the magnetic field distribution between the three-phase windings is more uniform, thereby improving the overall performance of the transformer. In addition, the three-column iron core structure simplifies the assembly process of the transformer, improves production efficiency, and is also conducive to heat dissipation, reduces temperature rise, and enhances the stability and reliability of the transformer.

[0046] In an exemplary embodiment, the transformer further comprises: a double-column iron core, wherein the second primary winding La' and the third primary winding Ln are coaxially sleeved on a first core of the double-column iron core, and the second secondary winding Lo is sleeved on a second core of the double-column iron core.

[0047] Exemplarily, the transformer adopts a double-column iron core structure, the second primary winding La' and the third primary winding Ln are coaxially sleeved on the first iron core of the double-column iron core, and the second secondary winding Lo is sleeved on the second iron core, which can effectively concentrate the magnetic flux, reduce leakage magnetic flux, and improve the magnetic circuit efficiency and energy transmission capacity of the transformer. At the same time, the double-column iron core structure simplifies the layout of the winding, making the overall structure of the transformer more compact, which is conducive to reducing the size of the equipment and saving installation space. In addition, it can also reduce the mutual interference between the windings and improve the stability and reliability of the system.

[0048] In an exemplary embodiment, the number of turns of the second secondary winding Lo is the same as the number of turns of the second primary winding La'.

[0049] Exemplarily, the number of turns of the second secondary winding Lo is the same as the number of turns of the second primary winding La', ensuring a voltage ratio of 1:1, thereby achieving lossless voltage transfer, which not only maintains the stability and purity of the output voltage, reduces losses and distortions during voltage conversion, but also simplifies the design and manufacture of the transformer and reduces production costs.

[0050] In an exemplary embodiment, the present application further provides a transformer device, which includes a three-phase to single-phase AC transformer as in the above embodiment.

[0051] In this embodiment, the transformer device provided by the present application includes the three-phase to single-phase AC transformer in the above embodiment, which can not only efficiently and stably convert three-phase AC power into single-phase AC power, but also significantly improve the conversion efficiency and output quality of the system through optimized winding configuration and core structure. In addition, the transformer device has a compact structure, simple design, easy installation and maintenance, reduces operating costs, and improves the reliability and adaptability of the system.

[0052] In an exemplary embodiment, the present application also provides a railway power transmission system, which includes the transformer device as described in the above embodiment.

[0053] In this embodiment, the railway power transmission system provided by this application includes the transformer device in the above embodiment. Based on the transformer device in the above embodiment, it can not only significantly improve the power conversion efficiency and output stability of the railway power transmission system, reduce electromagnetic interference and heat loss, but also reduce the operating cost and maintenance requirements of the system through compact structural design and efficient energy transmission. The railway power transmission system can provide higher quality single-phase power supply, ensure the stable operation of high-speed trains and other equipment, improve the safety and reliability of the entire railway system, and is particularly suitable for high-speed railways and urban rail transit systems that have strict requirements on power supply.

[0054] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic description of the above terms does not necessarily refer to the same embodiment or example.

[0055] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0056] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A three-phase to single-phase AC transformer, characterized in that: The transformer comprises: a first primary winding, a first secondary winding, a second primary winding, a third primary winding and a second secondary winding; Wherein, the first primary winding includes an A-phase primary winding, a B-phase primary winding, and a C-phase primary winding, the first end of the A-phase primary winding is used to connect to the A-phase alternating current, the first end of the B-phase primary winding is used to connect to the B-phase alternating current, and the first end of the C-phase primary winding is used to connect to the C-phase alternating current, and the second end of the A-phase primary winding, the second end of the B-phase primary winding, and the second end of the C-phase primary winding are connected to each other to form a neutral point; The first secondary winding comprises an A-phase secondary winding, a B-phase secondary winding, and a C-phase secondary winding, wherein the first end of the A-phase secondary winding is connected to the first end of the second primary winding, the second end of the A-phase secondary winding is connected to the second end of the second primary winding, the first end of the B-phase secondary winding is connected to the first end of the C-phase secondary winding to form a neutral point, the second end of the B-phase secondary winding is connected to the first end of the third primary winding, the second end of the C-phase secondary winding is connected to the second end of the third primary winding, the first end of the A-phase secondary winding and the first end of the A-phase primary winding are the same end, the first end of the B-phase secondary winding and the first end of the B-phase primary winding are the same end, and the first end of the C-phase secondary winding and the first end of the C-phase primary winding are the same end; The second secondary winding is coupled with the second primary winding and the third primary winding.

2. The three-phase to single-phase AC transformer according to claim 1, characterized in that: The A-phase primary winding, the B-phase primary winding and the C-phase primary winding have the same number of turns.

3. The three-phase to single-phase AC transformer according to claim 2, characterized in that: The number of turns of the A-phase secondary winding is the same as the number of turns of the A-phase primary winding, the number of turns of the B-phase secondary winding is the same as the number of turns of the B-phase primary winding, and the number of turns of the C-phase secondary winding is the same as the number of turns of the C-phase primary winding.

4. The three-phase to single-phase AC transformer according to claim 3, characterized in that: The number of turns of the second primary winding is the same as the number of turns of the A-phase secondary winding.

5. The three-phase to single-phase AC transformer according to claim 4, characterized in that: The number of turns of the third primary winding is equal to the number of turns of the A-phase secondary winding. times.

6. The three-phase to single-phase AC transformer according to claim 1, characterized in that: The transformer also includes: a three-column iron core; The A-phase primary winding and the A-phase secondary winding are coaxially sleeved on the first core of the three-column core, the B-phase primary winding and the B-phase secondary winding are coaxially sleeved on the second core of the three-column core, and the C-phase primary winding and the C-phase secondary winding are coaxially sleeved on the third core of the three-column core.

7. The three-phase to single-phase AC transformer according to claim 1, characterized in that: The transformer also includes: a double-column iron core; The second primary winding and the third primary winding are coaxially sleeved on the first core of the double-column core, and the second secondary winding is sleeved on the second core of the double-column core.

8. The three-phase to single-phase AC transformer according to claim 7, characterized in that: The number of turns of the second secondary winding is the same as the number of turns of the second primary winding.

9. A voltage transformer, characterized in that: The transformer device comprises a three-phase to single-phase AC transformer as described in any one of claims 1 to 8.

10. A railway power transmission system, characterized in that: The railway power transmission system comprises the transformer device according to claim 9.

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