Dual-mode hydrogen production rectifier transformer

Abstract

The invention provides a dual-mode hydrogen production rectifier transformer, and belongs to the technical field of transformers. The invention provides a dual-mode hydrogen production rectifier transformer. The dual-mode hydrogen production rectifier transformer comprises an iron core, an inner-layer coil assembly, a middle-layer coil assembly and an outer-layer coil assembly, the inner-layer coil group sleeves the outer side of the iron core and comprises a first main voltage regulating winding and a second main voltage regulating winding; the middle-layer coil assembly comprises a first branch winding and a second branch winding; the first branch winding sleeves the outer side of the first main voltage regulating winding and is provided with a first voltage regulating section; the second branch winding sleeves the outer side of the second main voltage regulating winding and is provided with a second voltage regulating section; the outer-layer coil assembly comprises a first low-voltage winding arranged outside the first branch winding in a sleeving manner and a second low-voltage winding arranged outside the second branch winding in a sleeving manner; the first low-voltage winding and the second low-voltage winding are used for being electrically connected with SCR rectifying equipment and IGBT rectifying equipment. The dual-mode hydrogen production rectifier transformer provided by the invention can be respectively adapted to SCR (Selective Catalytic Reduction) rectifying equipment and IGBT (Insulated Gate Bipolar Translator) rectifying equipment through voltage regulation, so that the number of transformers is reduced, and the cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of transformer technology, specifically relating to a dual-mode hydrogen production rectifier transformer. Background Technology

[0002] In existing hydrogen production systems, the hydrogen production rectifier power supply unit is a crucial component. This unit draws power from the AC grid and supplies it to the electrolyzer via power electronic conversion devices. The hydrogen production rectifier power supply unit directly impacts the long-term stable operation of the hydrogen production system, the lifespan of the electrolyzer, and the overall economic efficiency of the system.

[0003] Hydrogen production rectification technology generally includes two commonly used techniques: thyristor (SCR) rectification and insulated-gate bipolar transistor (IGBT) rectification. SCR rectification relies on thyristor (SCR) rectifiers and offers high efficiency under high load conditions, capable of handling high power output. However, its efficiency drops significantly at low loads (50% and below), and the rectifiers used are inexpensive. IGBT rectification, relying on insulated-gate bipolar transistor (IGBT) rectifiers, offers stable efficiency over a wide load range. Even under low load conditions (10-20%), efficiency can still remain above 85%, but the rectifiers used are more expensive.

[0004] To adapt to various load conditions, the two rectification methods can be combined for compatibility. SCR rectification is used under high load, while IGBT rectification is used under low load, which can cover the entire load range, achieve overall efficiency improvement and reduce energy consumption across the entire load range.

[0005] SCR rectification requires the use of an on-load tap-changing three-phase transformer to achieve a wider power regulation range; IGBT rectification requires the use of an off-load tap-changing three-phase transformer, whose voltage regulation range is smaller, typically ±5%. To meet the requirement of using both rectification methods, two corresponding transformers are needed, increasing investment costs and requiring a larger footprint. Summary of the Invention

[0006] The purpose of this invention is to provide a dual-mode hydrogen production rectifier transformer, which aims to solve the problems of high cost and large footprint when assembling SCR rectifier transformers and IGBT rectifier transformers simultaneously in hydrogen production systems.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a dual-mode hydrogen production rectifier transformer, comprising: an iron core, which is disposed in the enclosure of a three-phase transformer; The inner coil group is sleeved on the outside of the iron core and includes a first main voltage regulating winding and a second main voltage regulating winding distributed from top to bottom. The middle layer coil group includes a first sub-winding and a second sub-winding distributed from top to bottom; the first sub-winding is electrically connected to the first main voltage regulating winding and is sleeved outside the first main voltage regulating winding, and the first sub-winding has a first voltage regulating section for changing the voltage by adjusting the number of coil turns; the second sub-winding is electrically connected to the second main voltage regulating winding and is sleeved outside the second main voltage regulating winding, and the second sub-winding has a second voltage regulating section for changing the voltage by adjusting the number of coil turns; and The outer coil assembly includes a first low-voltage winding sleeved outside the first sub-winding and a second low-voltage winding sleeved outside the second sub-winding; the first low-voltage winding and the second low-voltage winding are used for electrical connection with the SCR rectifier and the IGBT rectifier.

[0008] In one possible implementation, the first low-voltage winding of the three phases of the transformer is connected in a delta connection (d connection); The second low-voltage winding of the three phases of the transformer is connected in a star connection (y-connection).

[0009] In one possible implementation, the first sub-winding includes a first upper high-voltage winding, a first auxiliary voltage regulating winding, and a first lower high-voltage winding distributed from top to bottom, wherein the first auxiliary voltage regulating winding is the first voltage regulating section. The second sub-winding is located outside the second main voltage regulating winding and includes a second upper high voltage winding, a second auxiliary voltage regulating winding, and a second lower high voltage winding distributed from top to bottom. The second auxiliary voltage regulating winding is the second voltage regulating section.

[0010] In one possible implementation, the two ends of the first main voltage regulating winding are connected to the first upper high voltage winding via a first changeover switch; the two ends of the second main voltage regulating winding are connected to the second upper high voltage winding via a second changeover switch.

[0011] In one possible implementation, the enclosure is further provided with an on-load tap changer, wherein the first main tap changer winding and the second main tap changer winding are both multi-stage series windings, and the first main tap changer winding and the second main tap changer winding are respectively connected to the on-load tap changer through tap leads.

[0012] In one possible implementation, the first main voltage regulating winding is partially or fully connected, the second main voltage regulating winding is partially or fully connected, and the outer coil group provides power to the SCR rectifier.

[0013] In one possible implementation, the two ends of the first auxiliary voltage regulating winding are respectively connected to the first upper high voltage winding and the first lower high voltage winding; The two ends of the second auxiliary voltage regulating winding are respectively connected to the second upper high voltage winding and the second lower high voltage winding.

[0014] In one possible implementation, the housing is further provided with a no-excitation voltage regulating switch, wherein the first auxiliary voltage regulating winding and the second auxiliary voltage regulating winding are both multi-stage bridging voltage regulating, and the first auxiliary voltage regulating winding and the second auxiliary voltage regulating winding are respectively connected to the no-excitation voltage regulating switch through tap leads.

[0015] In one possible implementation, the first auxiliary voltage regulating winding is partially or fully connected, the second auxiliary voltage regulating winding is partially or fully connected, and the outer coil group provides power to the IGBT rectifier.

[0016] In one possible implementation, the non-excitation voltage regulating switch is provided in two sets, with the first auxiliary voltage regulating winding and the second auxiliary voltage regulating winding each connected to a set of non-excitation voltage regulating switches.

[0017] The beneficial effects of the dual-mode hydrogen production rectifier transformer provided by this invention are as follows: Compared with existing technologies, the transformer is a three-phase transformer with a three-phase core. The coil structure on the outside of the core has three layers: an inner coil group, a middle coil group, and an outer coil group. The inner coil group is sleeved on the outside of the iron core, including a first main voltage regulating winding and a second main voltage regulating winding. The first main voltage regulating winding and the second main voltage regulating winding are set independently. The second main voltage regulating winding is set below the first main voltage regulating winding. The voltage regulation operation of the first main voltage regulating winding and the second main voltage regulating winding is achieved by adjusting the number of turns of the coil connected to the circuit system. The first main voltage regulating winding and the second main voltage regulating winding can be partially or fully connected to the circuit system, or they can be not connected to the circuit system. The middle layer coil group is sleeved on the outside of the inner layer coil group, including a first sub-winding group and a second sub-winding group. The second sub-winding group is located below the first sub-winding group. The first sub-winding group is sleeved on the outside of the first main voltage regulating winding group and connected to the first main voltage regulating winding group. Correspondingly, the second sub-winding group is sleeved on the outside of the second main voltage regulating winding group and connected to the second main voltage regulating winding group. The first sub-winding has a first voltage regulating section, and the second sub-winding has a second voltage regulating section. The first voltage regulating section and the second voltage regulating section can be used to regulate voltage by changing the number of coil turns of the first voltage regulating section and the second voltage regulating section connected to the circuit system to achieve voltage change. The first auxiliary voltage regulating winding and the second auxiliary voltage regulating winding can be partially or fully connected to the circuit system, or they can be not connected to the circuit system. The outer coil group is sleeved on the outside of the middle coil group, including a first low-voltage winding and a second low-voltage winding. The second low-voltage winding is located below the first low-voltage winding. The first low-voltage winding is located outside the first sub-winding, and the second low-voltage winding is located outside the second sub-winding. The outer coil assembly is used to connect with SCR rectifier equipment and IGBT rectifier equipment, and the SCR rectifier equipment and IGBT rectifier equipment are connected in parallel; When used in this application, the circuit system structure is adjusted by changing the number of turns of the coils connected to the first main voltage regulating winding, the second main voltage regulating winding, the first auxiliary voltage regulating winding, and the second auxiliary voltage regulating winding. This adjusts the voltage level generated by the transformer, making the adjusted voltage level suitable for SCR rectifier equipment or IGBT rectifier equipment. One set of transformers can meet the voltage requirements of both SCR rectifier equipment and IGBT rectifier equipment, reducing the number of transformers, lowering transformer costs, and reducing the footprint of the device. In addition, this application is also applicable to mixed testing application scenarios of SCR rectifier equipment and IGBT rectifier equipment. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a rectifier transformer for hydrogen production provided in an embodiment of the present invention; Figure 2 A schematic diagram of the circuit system structure of a rectifier transformer for hydrogen production provided in an embodiment of the present invention; Figure 3 A schematic diagram of the circuit system structure of a second embodiment of the rectifier transformer for hydrogen production provided in this invention; Figure 4 The rectifier principle diagram of the rectifier transformer for hydrogen production provided in the embodiments of the present invention.

[0020] In the diagram: 1. Iron core; 2. First main voltage regulating winding; 3. Second main voltage regulating winding; 4. First changeover switch; 5. Second changeover switch; 6. First upper high voltage winding; 7. First auxiliary voltage regulating winding; 8. First lower high voltage winding; 9. Second upper high voltage winding; 10. Second auxiliary voltage regulating winding; 11. Second lower high voltage winding; 12. First low voltage winding; 13. Second low voltage winding; 14. On-load tap changer; 15. Off-load tap changer; 16. First off-load tap changer; 17. Second off-load tap changer. Detailed Implementation

[0021] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0022] Please refer to Figures 1 to 3 The following describes a specific embodiment of a dual-mode hydrogen production rectifier transformer provided by the present invention. Please refer to [link / reference]. Figure 1 The SCR rectifier and IGBT rectifier are power-consuming devices and can be collectively referred to as load rectifiers. The SCR rectifier and IGBT rectifier are connected in parallel and operate independently. After the SCR rectifier and IGBT rectifier are connected in parallel, they are connected to the output terminal of the transformer of this application. That is, the transformer of this application can be connected to either the SCR rectifier or the IGBT rectifier.

[0023] The transformer is a three-phase transformer, and the core 1 is a three-phase core 1. The core 1 can be a three-phase three-limb type or a three-phase five-limb type, which is suitable for power grid, SCR rectifier equipment, and IGBT rectifier equipment. The coil structure on the outside of the core 1 of each phase is the same. The transformer circuit system is the collection of circuits that connect the power grid and the load rectifier equipment when the transformer is working, that is, the collection of coil structures connected when the transformer is working.

[0024] Please refer to Figures 1 to 3 Each phase of the iron core 1 has a total of three layers of coil structure on the outside: inner coil group, middle coil group, and outer coil group.

[0025] Optionally, an inner paper tube may be fitted on the outside of the iron core 1, and the inner coil assembly may be fitted on the outside of the inner paper tube.

[0026] The inner coil group is sleeved on the outside of the iron core 1. The inner coil group includes a first main voltage regulating winding 2 and a second main voltage regulating winding 3. The first main voltage regulating winding 2 and the second main voltage regulating winding 3 are set independently. The first main voltage regulating winding 2 and the second main voltage regulating winding 3 are distributed vertically. The second main voltage regulating winding 3 is set below the first main voltage regulating winding 2.

[0027] Both the first main voltage regulating winding 2 and the second main voltage regulating winding 3 have voltage regulating functions. The voltage regulation operation is achieved by adjusting the number of turns of the coils of the first main voltage regulating winding 2 and the second main voltage regulating winding 3 connected to the circuit system. The first main voltage regulating winding 2 and the second main voltage regulating winding 3 can be partially or fully connected to the circuit system, or they can be not connected to the circuit system.

[0028] The first main voltage regulating winding 2 and the second main voltage regulating winding 3 are independent of each other and are not connected. In the height direction of the core 1, the first main voltage regulating winding 2 and the second main voltage regulating winding 3 are symmetrically arranged with the horizontal centerline of the core 1 as the axis of symmetry.

[0029] Taking the first main voltage regulating winding 2 as an example, the first main voltage regulating winding 2 has a first end, a voltage regulating body part and a second end in its length direction. The voltage regulating body part of the first main voltage regulating winding 2 is arranged along the height direction of the iron core 1. The first end of the first main voltage regulating winding 2 extends and is arranged on the side of the voltage regulating body part away from the iron core 1. The second end of the first main voltage regulating winding 2 extends and is arranged on the side of the voltage regulating body part away from the iron core 1. The first end of the first main voltage regulating winding 2 is located above the second end of the first main voltage regulating winding 2.

[0030] The first end of the first main voltage regulating winding 2 and the second end of the first main voltage regulating winding 2 are connected by a first changeover switch 4. The first end of the first changeover switch 4 is hinged, and the second end is a switch end. The switch end of the first changeover switch 4 can be connected to the first end of the first main voltage regulating winding 2, or it can be rotated and connected to the second end of the first main voltage regulating winding 2.

[0031] Correspondingly, the second main voltage regulating winding 3 has a first end, a voltage regulating body portion and a second end in its length direction. The voltage regulating body portion of the second main voltage regulating winding 3 is arranged along the height direction of the iron core 1. The first end of the second main voltage regulating winding 3 extends and is arranged on the side of the voltage regulating body portion away from the iron core 1. The second end of the second main voltage regulating winding 3 extends and is arranged on the side of the voltage regulating body portion away from the iron core 1. The first end of the second main voltage regulating winding 3 is located below the second end of the second main voltage regulating winding 3.

[0032] The first end of the second main voltage regulating winding 3 and the second end of the second main voltage regulating winding 3 are connected by a second changeover switch 5. The first end of the second changeover switch 5 is hinged, and the second end is a switch end. The switch end of the second changeover switch 5 can be connected to the second end of the second main voltage regulating winding 3, or it can be rotated and connected to the second end of the second main voltage regulating winding 3.

[0033] The middle layer coil group is sleeved outside the inner layer coil group, including a first sub-winding group and a second sub-winding group. The first sub-winding group and the second sub-winding group are distributed vertically. The second sub-winding group is located below the first sub-winding group. The first sub-winding group is sleeved outside the first main voltage regulating winding 2 and is connected to the first main voltage regulating winding 2 through a first changeover switch 4. The first end of the first changeover switch 4 is connected to the first sub-winding group through a lead wire. Correspondingly, the second sub-winding group is sleeved outside the second main voltage regulating winding 3 and is connected to the second main voltage regulating winding 3.

[0034] The first sub-winding includes a first upper high voltage winding 6, a first auxiliary voltage regulating winding 7, and a first lower high voltage winding 8. The first upper high voltage winding 6, the first auxiliary voltage regulating winding 7, and the first lower high voltage winding 8 are connected sequentially from top to bottom. The first auxiliary voltage regulating winding 7 is the first voltage regulating section.

[0035] The upper end of the first upper high voltage winding 6 is connected to the first terminal of the first changeover switch 4 via a lead wire. The lower end of the first upper high voltage winding 6 is connected to the upper end of the first auxiliary voltage regulating winding 7. The lower end of the first auxiliary voltage regulating winding 7 is connected to the upper end of the first lower high voltage winding 8. The lower end of the first lower high voltage winding 8 is connected to the middle layer coil lead wire and led out through the middle layer coil lead wire. The middle layer coil lead wire is connected to the power grid.

[0036] Correspondingly, the second sub-winding includes the second upper high voltage winding 9, the second auxiliary voltage regulating winding 10, and the second lower high voltage winding 11. The second upper high voltage winding 9, the second auxiliary voltage regulating winding 10, and the second lower high voltage winding 11 are connected sequentially from top to bottom. The second auxiliary voltage regulating winding 10 is the second voltage regulating section.

[0037] The lower end of the second lower high voltage winding 11 is connected to the first end of the second changeover switch 5 via a lead wire. The upper end of the second lower high voltage winding 11 is connected to the lower end of the second auxiliary voltage regulating winding 10. The upper end of the second auxiliary voltage regulating winding 10 is connected to the lower end of the second upper high voltage winding 9. The upper end of the second upper high voltage winding 9 is connected to the middle layer coil lead wire and led out through the middle layer coil lead wire. The middle layer coil lead wire is connected to the power grid.

[0038] Both the first auxiliary voltage regulating winding 7 and the second auxiliary voltage regulating winding 10 have voltage regulating functions. The voltage regulation operation is achieved by adjusting the number of turns of the coils of the first auxiliary voltage regulating winding 7 and the second auxiliary voltage regulating winding 10 connected to the circuit system. The first auxiliary voltage regulating winding 7 and the second auxiliary voltage regulating winding 10 can be partially or fully connected to the circuit system, or they can be not connected to the circuit system.

[0039] The ratio of the number of turns of the first high-voltage winding 6 to the sum of the number of turns of the first high-voltage winding 6 and the second high-voltage winding 9 is between 0.7 and 0.8.

[0040] The ratio of the number of turns of the second lower high-voltage winding 11 to the sum of the number of turns of the second upper high-voltage winding 9 and the second lower high-voltage winding 11 is between 0.7 and 0.8.

[0041] The outer coil group is sleeved on the outside of the middle coil group, including a first low-voltage winding 12 and a second low-voltage winding 13. The first low-voltage winding 12 and the second low-voltage winding 13 are set independently. The second low-voltage winding 13 is set below the first low-voltage winding 12. The first low-voltage winding 12 is set on the outside of the first sub-winding, and the second low-voltage winding 13 is set on the outside of the second sub-winding.

[0042] The first low-voltage winding 12 and the second low-voltage winding 13 are independent of each other and are not connected. In the height direction of the core 1, the first low-voltage winding 12 and the second low-voltage winding 13 are symmetrically arranged with the horizontal centerline of the core 1 as the axis of symmetry.

[0043] Taking the first low-voltage winding 12 as an example, the upper end of the first low-voltage winding 12 is led out in a direction away from its iron core 1, and the lower end of the first low-voltage winding 12 is led out in a direction away from its iron core 1; correspondingly, the upper end of the second low-voltage winding 13 is led out in a direction away from its iron core 1, and the lower end of the second low-voltage winding 13 is led out in a direction away from its iron core 1.

[0044] The first low-voltage winding 12 and the second low-voltage winding 13 are led out through the transformer outlet bushing. The transformer outlet bushing is connected to the load rectifier through a short-circuit copper busbar or cable to supply power to the load rectifier.

[0045] When this application is used, the circuit system structure is adjusted by adjusting the number of turns of the coils connected to the circuit system in the first main voltage regulating winding 2, the second main voltage regulating winding 3, the first auxiliary voltage regulating winding 7, and the second auxiliary voltage regulating winding 10. This adjusts the voltage level generated by the transformer, making the adjusted voltage level suitable for SCR rectifier equipment or IGBT rectifier equipment. One set of transformers can meet the voltage requirements of both SCR rectifier equipment and IGBT rectifier equipment, reducing the number of transformers, lowering the cost of transformers, and reducing the footprint of the device. In addition, this application is also applicable to mixed testing application scenarios of SCR rectifier equipment and IGBT rectifier equipment.

[0046] Please refer to Figure 4 The first low-voltage winding 12 of the three-phase transformer is connected in a delta connection (d-connection); the second low-voltage winding 13 of the three-phase transformer is connected in a star connection (y-connection). The first low-voltage winding 12 and the second low-voltage winding 13 are adapted to connect to the SCR rectifier and the IGBT rectifier, and serve as a power source to supply power to the SCR rectifier and the IGBT rectifier.

[0047] Please refer to Figures 1 to 3 The enclosure is also equipped with an on-load tap changer 14. The first main tap changer winding 2 and the second main tap changer winding 3 are both multi-stage series windings. The first main tap changer winding 2 and the second main tap changer winding 3 are respectively connected to the on-load tap changer 14 through tap leads.

[0048] The on-load tap changer 14 is used to regulate the voltage of the first main voltage regulating winding 2 and the second main voltage regulating winding 3. The voltage regulation methods of the first main voltage regulating winding 2 and the second main voltage regulating winding 3 are the same.

[0049] The first main voltage regulating winding 2 has multiple taps, which are positioned facing the on-load tap changer 14. The selector switch of the on-load tap changer 14 can select the connected taps, thereby adjusting the number of coil turns of the first main voltage regulating winding 2 connected to the circuit system to achieve voltage regulation.

[0050] Correspondingly, the second main voltage regulating winding 3 has multiple taps, which are positioned toward the on-load tap changer 14. The selector switch of the on-load tap changer 14 can select the connected taps and adjust the number of coil turns of the second main voltage regulating winding 3 connected to the circuit system to achieve voltage regulation.

[0051] Along the height direction of the first main voltage regulating winding 2, the taps are arranged from bottom to top as 1, 2, 3...n-1, n; along the height direction of the second main voltage regulating winding 3, the taps are arranged from top to bottom as 1, 2, 3...n-1, n.

[0052] Please refer to Figure 2 The housing is also equipped with a no-excitation voltage regulating switch 15. The first auxiliary voltage regulating winding 7 and the second auxiliary voltage regulating winding 10 are both multi-stage bridging voltage regulating. The first auxiliary voltage regulating winding 7 and the second auxiliary voltage regulating winding 10 are respectively connected to the no-excitation voltage regulating switch 15 through tap leads. The no-excitation voltage regulating switch 15 is used to perform voltage regulating operations on the first auxiliary voltage regulating winding 7 and the second auxiliary voltage regulating winding 10.

[0053] Along the height direction of the first auxiliary voltage regulating winding 7, multiple sets of connectors are provided from top to bottom on the first auxiliary voltage regulating winding 7; along the height direction of the second auxiliary voltage regulating winding 10, multiple sets of connectors are provided from top to bottom on the second auxiliary voltage regulating winding 10.

[0054] The no-excitation voltage regulator 15 is provided with a moving contact and multiple sets of stationary contacts. The multiple sets of stationary contacts are arranged along the circumference of the no-excitation voltage regulator 15, and the moving contact is used to connect different stationary contacts.

[0055] The number of taps in the first auxiliary voltage regulating winding 7 is the same as the number of stationary contacts in the off-magnetic voltage regulating switch 15, and the number of taps in the second auxiliary voltage regulating winding 10 is the same as the number of stationary contacts in the off-magnetic voltage regulating switch 15.

[0056] The taps of the first auxiliary voltage regulating winding 7 are numbered 1, 2, 3...n-1, n from top to bottom; the taps of the second auxiliary voltage regulating winding 10 are numbered 1, 2, 3...n-1, n from top to bottom; and the stationary contacts of the de-energized voltage regulating switch 15 are numbered 1, 2, 3...n-1, n in a counterclockwise direction.

[0057] Each set of stationary contacts of the non-excitation voltage regulating switch 15 is connected to a contact connection wire, which is used to connect the tap lead of the tap of the first auxiliary voltage regulating winding 7 and the tap lead of the tap of the second auxiliary voltage regulating winding 10.

[0058] The tap 1 of the first auxiliary voltage regulating winding 7 is electrically connected to the stationary contact 1 of the non-excitation voltage regulating switch 15; the tap 1 of the second auxiliary voltage regulating winding 10 is electrically connected to the stationary contact 1 of the non-excitation voltage regulating switch 15; the tap 2 of the first auxiliary voltage regulating winding 7 is electrically connected to the stationary contact 2 of the non-excitation voltage regulating switch 15; the tap 2 of the second auxiliary voltage regulating winding 10 is electrically connected to the stationary contact 2 of the non-excitation voltage regulating switch 15; and so on; the tap n of the first auxiliary voltage regulating winding 7 is electrically connected to the stationary contact n of the non-excitation voltage regulating switch 15; the tap 1 of the second auxiliary voltage regulating winding 10 is electrically connected to the stationary contact n of the non-excitation voltage regulating switch 15.

[0059] Optional, please refer to Figure 3 The off-magnet voltage regulator 15 is provided with two sets, namely the first off-magnet voltage regulator 16 and the second off-magnet voltage regulator 17. The first auxiliary voltage regulating winding 7 is connected to the first off-magnet voltage regulator 16, and the second auxiliary voltage regulating winding 10 is connected to the second off-magnet voltage regulator 17.

[0060] The stationary contacts of the first non-excitation voltage regulating switch 16 are arranged in a counterclockwise direction as 1, 2, 3...n-1, n; the tap 1 of the first auxiliary voltage regulating winding 7 is electrically connected to the stationary contact 1 of the non-excitation voltage regulating switch 15; the tap 2 of the first auxiliary voltage regulating winding 7 is electrically connected to the stationary contact 2 of the non-excitation voltage regulating switch 15; and so on; the tap n of the first auxiliary voltage regulating winding 7 is electrically connected to the stationary contact n of the non-excitation voltage regulating switch 15.

[0061] The stationary contacts of the second non-excitation voltage regulating switch 17 are arranged in a counterclockwise direction as 1, 2, 3...n-1, n; the tap 1 of the second auxiliary voltage regulating winding 10 is electrically connected to the stationary contact 1 of the non-excitation voltage regulating switch 15; the tap 2 of the second auxiliary voltage regulating winding 10 is electrically connected to the stationary contact 2 of the non-excitation voltage regulating switch 15; and so on; the tap n of the second auxiliary voltage regulating winding 10 is electrically connected to the stationary contact n of the non-excitation voltage regulating switch 15.

[0062] Two sets of de-energized voltage regulating switches 15 are provided to prevent the generation of circulating current.

[0063] Please refer to Figures 1 to 4 The transformer involved in this application has two modes during use, which are respectively adapted to SCR rectifier equipment and IGBT rectifier equipment.

[0064] Mode 1: The on-load tap changer controls the first main voltage regulating winding 2 to be partially or completely connected to the first upper high voltage winding 6, and the second main voltage regulating winding 3 to be partially or completely connected to the second upper high voltage winding 9. The off-load voltage regulating switch 15 controls the first auxiliary voltage regulating winding 7 and the second auxiliary voltage regulating winding 10 to be disconnected from the circuit system. The on-load tap changer can adjust the number of coil turns of the first main voltage regulating winding 2 and the second main voltage regulating winding 3 connected to the circuit system, and adjust the output voltage of the first low voltage winding 12 and the second low voltage winding 13. This is a variable flux voltage regulation mode. At this time, it is a high load condition. The first low voltage winding 12 and the second low voltage winding 13 can be used as the power supply for the SCR rectifier equipment to provide power to the SCR rectifier equipment.

[0065] Mode 1 is the "full-through operation" mode. The first main voltage regulating winding 2 and the first upper high voltage winding 6 are connected. The impedance of the second main voltage regulating winding 3 and the second upper high voltage winding 9 to the first low voltage winding 12 and the second low voltage winding 13 is defined as the "full-through impedance Z". q When all windings except the first low-voltage winding 12 and the second low-voltage winding 13 are in an open-circuit state, the impedance between the two low-voltage windings is called the "split impedance". The ratio of the split impedance to the total through impedance is called the "split coefficient K". f "Split coefficient K" f Keep it between 3.5 and 4.

[0066] In full-pass operation mode, the voltage phase difference between the first low-voltage winding 12 and the second low-voltage winding 13 is 30°. The average DC voltage outputs of the rectifier bridge connected to the first low-voltage winding 12 and the rectifier bridge connected to the second low-voltage winding 13 are equal, but their instantaneous values ​​are different, resulting in an instantaneous voltage difference between the two rectifier bridges. Due to this instantaneous voltage difference, a circulating current I is generated in the large loop between the first low-voltage winding 12, the second low-voltage winding 13, and the rectifier. xh By setting the splitting impedance value appropriately, the circulating current can be limited to a reasonable range; therefore, the splitting coefficient K... f Keep it between 3.5 and 4.

[0067] Mode 2: On-load tap changer controls the first main voltage regulating winding 2 and the second main voltage regulating winding 3 to not be connected to the circuit system; off-load tap changer 15 controls the first auxiliary voltage regulating winding 7 to be partially or fully connected to the first upper high voltage winding 6 and the first lower high voltage winding 8, and controls the second auxiliary voltage regulating winding 10 to be partially or fully connected to the second upper high voltage winding 9 and the second lower high voltage winding 11; off-load tap changer 15 can adjust the number of coil turns of the first auxiliary voltage regulating winding 7 and the second auxiliary voltage regulating winding 10 connected to the circuit system.

[0068] The first low-voltage winding 12 and the second low-voltage winding 13 serve as the power supply for the IGBT rectifier, providing power to the IGBT rectifier. The output voltage of the first low-voltage winding 12 and the second low-voltage winding 13 is adjusted, and the grid voltage fluctuation of the first upper high-voltage winding 6, the first lower high-voltage winding 8, the second upper high-voltage winding 9, and the second lower high-voltage winding 11 is adjusted. This is constant flux voltage regulation, which is a low load condition.

[0069] The first low-voltage winding 12 and the second low-voltage winding 13 can be either set to an open circuit state, or the other set can be used as the power supply for the IGBT rectifier equipment. This is the "semi-crossover operation" mode.

[0070] In the semi-crossover operation mode, the first main voltage regulating winding 2 and the first upper high-voltage winding 6 are connected. The impedance of the low-voltage winding of the IGBT rectifier connected to the first low-voltage winding 12 and the second low-voltage winding 13, which is the second main voltage regulating winding 3 and the second upper high-voltage winding 9, is defined as the "semi-crossover impedance Z". b ".

[0071] In the semi-crossover operation mode, one of the first low-voltage winding 12 and the second low-voltage winding 13 serves as the power supply for the IGBT rectifier and is connected to the circuit system. The upper and lower magnetic circuits are asymmetrical. The coupling degree between the first auxiliary voltage regulating winding 7 and the second auxiliary voltage regulating winding 10 and the low-voltage winding of the IGBT rectifier that is not connected to the first low-voltage winding 12 and the second low-voltage winding 13 is inconsistent, resulting in circulating current. Two sets of no-excitation voltage regulating switches 15 are provided. The first auxiliary voltage regulating winding 7 and the second auxiliary voltage regulating winding 10 are connected to different no-excitation voltage regulating switches 15, which can effectively cut off the circulating current flow path and avoid the generation of circulating current.

[0072] In full-pass operation mode, the circulation current flows between the two rectifier bridges that are conducting SCR rectifier devices and the transformer secondary winding. The circulation current changes its direction of flow as the rectifier components commutate. The frequency of the circulation current is 6 times the power supply voltage frequency.

[0073] According to the commutation rule, assuming that starting from b1c1, the conduction sequence of the line voltage is as follows: b1c1→b2c2→b1a1→b2a2→c1a1→c2a2→c1b1→c2b2→a1b1→a2b2→a1c1→a2c2→b1c1.

[0074] Instantaneous value of the circulating voltage of the circulating current: (Formula 1) When represented as an equivalent sine wave, the root mean square effective value of the cyclic voltage is approximately: (Formula 2) Among them: Uxh U is the instantaneous value of the circulating voltage of the circulating current. b1c1 U is the line voltage at which b1c1 is turned on. b2c2 U2 is the line voltage at which b2c2 conducts, and U2 is the effective value of the secondary voltage. ω is the angular frequency, and t is the duration.

[0075] When the circulating current is greater than the operating current, it will flow within the circulating path. The dotted-line path represents an example at one moment. The circulating current path includes the split impedance of two 6-pulse low-voltage windings because the frequency of the circulating current is 6 times the frequency of the power supply voltage. That is: (Formula 3) in, For circulating current, The impedance of the loop is... This is the splitting impedance.

[0076] Assume the transformer's primary winding is connected in a d-shape with n turns, the first low-voltage winding has 12 turns and n turns, and the second low-voltage winding has 13 turns and n turns. Turns, The percentage of circulating current referred to the primary side: (Formula 4) in, This is the per-unit value of the split impedance. U1 is the effective value of the primary line current, and U2 is the effective value of the primary line voltage.

[0077] The percentage of circulating current referred to the DC side: (Formula 5) in, This is the load current.

[0078] To reduce circulating current, the splitting factor K of the transformer involved in this application... f The impedance should be controlled between 3.5 and 4. Therefore, when the "half-through impedance Z" is... b When it is 7%, the total passthrough impedance Z q "It is around 7.5%, splitting impedance" Between 24% and 30%, it can be calculated that Between 4.2% and 5.2%, the circulating current ratio is controlled within a small range, and the parallel operation of the two rectifier bridges does not require the addition of a balancing reactor.

[0079] Due to structural reasons, the semi-passing impedance of the secondary winding is not equal to that of the primary winding. Under load operation, this will lead to unequal output voltage and increase the circulating current. To limit the circulating current, the reactance of the first low-voltage winding 12 and the second low-voltage winding 13 is the same. When the transformer adopts the top-outlet design, the second low-voltage winding 13 is placed above the first low-voltage winding 12 in the axial direction.

[0080] In practical applications, the number of turns of the first low-voltage winding 12 and the second low-voltage winding 13 is not strictly equal to 3, which will also affect the circulating current. The design number of turns of the first low-voltage winding 12 and the second low-voltage winding 13 needs to be controlled so that the deviation of the no-load voltage ratio is less than 1%.

[0081] The transformer used in this application can reduce investment costs and reduce the footprint by approximately 30% to 40%. Under different operating conditions, the circulating current can be limited to a reasonable range.

[0082] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dual-mode hydrogen production rectifier transformer, characterized in that, include: The core is housed within the casing of a three-phase transformer. The inner coil group is sleeved on the outside of the iron core and includes a first main voltage regulating winding and a second main voltage regulating winding distributed from top to bottom. The middle layer coil group includes a first sub-winding and a second sub-winding distributed from top to bottom; the first sub-winding is electrically connected to the first main voltage regulating winding and is sleeved on the outside of the first main voltage regulating winding, and the first sub-winding has a first voltage regulating section for changing the voltage by adjusting the number of coil turns; the second sub-winding is electrically connected to the second main voltage regulating winding and is sleeved on the outside of the second main voltage regulating winding, and the second sub-winding has a second voltage regulating section for changing the voltage by adjusting the number of coil turns; as well as The outer coil assembly includes a first low-voltage winding sleeved outside the first sub-winding and a second low-voltage winding sleeved outside the second sub-winding; the first low-voltage winding and the second low-voltage winding are used for electrical connection with the SCR rectifier and the IGBT rectifier.

2. The dual-mode hydrogen production rectifier transformer as described in claim 1, characterized in that, The first low-voltage winding of the three phases of the transformer is connected in a delta connection (d connection); The second low-voltage winding of the three phases of the transformer is connected in a star connection (y-connection).

3. The dual-mode hydrogen production rectifier transformer as described in claim 1, characterized in that, The first sub-winding includes a first upper high voltage winding, a first auxiliary voltage regulating winding, and a first lower high voltage winding distributed from top to bottom, wherein the first auxiliary voltage regulating winding is the first voltage regulating section; The second sub-winding is located outside the second main voltage regulating winding and includes a second upper high voltage winding, a second auxiliary voltage regulating winding, and a second lower high voltage winding distributed from top to bottom. The second auxiliary voltage regulating winding is the second voltage regulating section.

4. A dual-mode hydrogen production rectifier transformer as described in claim 3, characterized in that, The two ends of the first main voltage regulating winding are connected to the first upper high voltage winding through a first changeover switch; the two ends of the second main voltage regulating winding are connected to the second upper high voltage winding through a second changeover switch.

5. A dual-mode hydrogen production rectifier transformer as described in claim 4, characterized in that, The enclosure is also equipped with an on-load tap changer. The first main tap changer winding and the second main tap changer winding are both multi-stage series windings. The first main tap changer winding and the second main tap changer winding are respectively connected to the on-load tap changer through tap leads.

6. A dual-mode hydrogen production rectifier transformer as described in claim 5, characterized in that, The first main voltage regulating winding is partially or completely connected, the second main voltage regulating winding is partially or completely connected, and the outer coil group provides power to the SCR rectifier.

7. A dual-mode hydrogen production rectifier transformer as described in claim 3, characterized in that, The two ends of the first auxiliary voltage regulating winding are respectively connected to the first upper high voltage winding and the first lower high voltage winding; The two ends of the second auxiliary voltage regulating winding are respectively connected to the second upper high voltage winding and the second lower high voltage winding.

8. A dual-mode hydrogen production rectifier transformer as described in claim 7, characterized in that, The housing is also equipped with a no-excitation voltage regulating switch. Both the first auxiliary voltage regulating winding and the second auxiliary voltage regulating winding are multi-stage bridging voltage regulating windings. The first auxiliary voltage regulating winding and the second auxiliary voltage regulating winding are respectively connected to the no-excitation voltage regulating switch through tap leads.

9. A dual-mode hydrogen production rectifier transformer as described in claim 8, characterized in that, The first auxiliary voltage regulating winding is partially or fully connected, the second auxiliary voltage regulating winding is partially or fully connected, and the outer coil group provides power to the IGBT rectifier.

10. A dual-mode hydrogen production rectifier transformer as described in claim 9, characterized in that, The non-excitation voltage regulating switch is provided in two sets, with the first auxiliary voltage regulating winding and the second auxiliary voltage regulating winding each connected to a set of non-excitation voltage regulating switches.

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