A multilevel converter structure

Abstract

The application relates to the field of power electronics, and discloses a multi-level converter valve structure, wherein the multi-level converter valve structure comprises a switching capacitor valve tower group and a plurality of commutation bridge valve towers; the switching capacitor valve tower group comprises three switching capacitor valve towers with a phase difference; the plurality of commutation bridge valve towers are connected in series, each commutation bridge valve tower is connected in parallel with each switching capacitor valve tower, the commutation bridge valve tower comprises a plurality of bridge modules arranged in a stack, each layer of the bridge modules comprises a plurality of valve modules connected in series, the valve module comprises a power device valve string, a capacitor assembly, a power supply assembly, a central control assembly and a module frame, the power device valve string, the capacitor assembly and the power supply assembly are mounted on the module frame along a first direction, the central control assembly is arranged on a side of the power device valve string away from the module frame along a stacking direction, the power device valve string, the capacitor assembly, the power supply assembly and the central control assembly are arranged in extension along a second direction, and the first direction, the second direction and the stacking direction are perpendicular to each other. The multi-level converter valve structure can reduce the floor area.

Description

Technical Field

[0001] This application belongs to the field of converters, and in particular relates to a multilevel converter valve structure. Background Technology

[0002] A power converter is a device that converts electrical energy from one form to another through the on / off control of power electronic devices. Its core function is to change the form of electrical energy (AC / DC conversion) or adjust electrical parameters (such as voltage amplitude, frequency, and phase). A multi-level converter valve structure is a converter topology that uses a series / parallel combination of multiple power devices to create an output voltage with "multiple discrete level steps." In medium- and high-voltage, high-power scenarios, this reduces the voltage stress on individual power devices while making the output waveform closer to a sine wave (reducing harmonic pollution).

[0003] However, existing multilevel converter valves have complex structures and occupy a large amount of space. Summary of the Invention

[0004] This application provides a multilevel converter valve structure that can reduce the footprint of the multilevel converter valve structure.

[0005] On one hand, this application provides a multi-level converter valve structure, including a switched capacitor valve tower group and multiple commutation bridge valve towers. The switched capacitor valve tower group includes three switched capacitor valve towers with a phase difference. The multiple commutation bridge valve towers are connected in series, and each commutation bridge valve tower is connected in parallel with each switched capacitor valve tower. The commutation bridge valve tower includes multiple bridge modules stacked in layers. Each layer of bridge module includes multiple valve modules connected in series. The valve module includes a power device valve string, a capacitor assembly, a power supply assembly, a central control assembly, and a module frame. The power device valve string, capacitor assembly, and power supply assembly are installed on the module frame along a first direction. The central control assembly is disposed on the side of the power device valve string away from the module frame along the stacking direction. The power device valve string, capacitor assembly, power supply assembly, and central control assembly are all arranged extending along a second direction. The first direction, the second direction, and the stacking direction are perpendicular to each other.

[0006] In some embodiments, the power device valve string includes a plurality of power devices, a plurality of heat exchangers and a locking assembly, wherein the power devices and heat exchangers are alternately arranged along a second direction; the locking assembly includes two end plates, a tensioning member and an elastic member, wherein the plurality of power devices and the plurality of heat exchangers are located between the two end plates, the two end plates are connected by the tensioning member, and the elastic member abuts against at least one end plate and a power device.

[0007] In some embodiments, the plurality of power device valve strings include an integrated gate-commutated thyristor valve string and a diode valve string, wherein the integrated gate-commutated thyristor valve string is located on one side of the diode valve string along a first direction; and the central control component is disposed on the diode valve string along the stacking direction.

[0008] In some embodiments, the diode valve string is located at one end of the valve module along a first direction.

[0009] In some embodiments, the bridge module includes a first switch module and a second switch module arranged at intervals. Both the first switch module and the second switch module have multiple valve modules. Along the stacking direction, two adjacent first switch modules are connected in series to form a first bridge arm; and two adjacent second switch modules are connected in series along the stacking direction to form a second bridge arm.

[0010] In some embodiments, two adjacent first bridge arms are connected in series along the stacking direction to form a third bridge arm; two adjacent second bridge arms are connected in series along the stacking direction to form a fourth bridge arm; and the third and fourth bridge arms are connected in parallel.

[0011] In some embodiments, three switched capacitor valve towers are arranged at intervals along the row direction, and multiple commutator bridge valve towers are arranged at intervals along the row direction, with each commutator bridge valve tower arranged opposite to each switched capacitor valve tower.

[0012] In some embodiments, multiple commutator bridge towers are located on one side of three switched capacitor towers along the column direction.

[0013] In some embodiments, multiple commutator bridge towers are located on one side of three switched capacitor towers along the stacking direction.

[0014] In some embodiments, the switched capacitor valve tower is a supported valve tower structure, and the reversing bridge valve tower is a suspended valve tower structure.

[0015] The multilevel converter valve structure of this application embodiment, by arranging the power device valve string, capacitor assembly, power supply assembly and central control assembly in the valve module all extending along the second direction, makes the uniformly shaped devices arranged in rows, and installed along the first direction on the module frame, making the structural layout of the valve structure more regular, reducing the space occupation, and stacking the central control assembly on the power device valve string, making reasonable use of the height space, improving the space utilization rate, and reducing the volume of the entire commutation bridge valve tower. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of an example of a multilevel converter valve structure according to some embodiments of this application; Figure 2 Show Figure 1 A schematic diagram of the structure of a reversing bridge valve tower from one perspective; Figure 3Show Figure 2 Schematic diagram of the middle valve module; Figure 4 Show Figure 3 A schematic diagram of a power device valve string structure; Figure 5 Show Figure 2 Another structural schematic diagram of the reversing bridge valve tower; Figure 6 Show Figure 1 A schematic diagram of the structure of another example of a reversing bridge valve tower; Figure 7 This is a schematic diagram of another example of a multilevel converter valve structure according to some embodiments of this application.

[0018] Explanation of reference numerals in the attached figures: 100. Switched capacitor valve tower; 200. Reversing bridge valve tower; 201. Power device valve string; 201b. Diode valve string; 201a. Thyristor valve string; 202. Capacitor assembly; 203. Power supply assembly; 204. Central control assembly; 205. Module frame; 206. Power device; 207. Heat exchanger; 208. Locking assembly; 210. Bridge module; 216. Tensioner; 211. Valve module; 212. Elastic element; 213. End plate; 214. 1. Switch module; 215. Second switch module; 217. First support beam; 218. Second support beam; 219. Insulating beam; 221. Third support beam; 220. First bridge arm; 230. Second bridge arm; 240. Insulator; 250. Shielding cover; 260. Equalizing ring; 270. Interlayer insulation component; 280. Pipeline / water pipe; M. Row direction; N. Column direction; X. First direction; Y. Second direction; Z. Stacking direction. Detailed Implementation

[0019] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0021] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0023] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0024] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0025] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0026] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0027] Taking the Modular Multilevel Converter (MMC) structure as an example, the basic topology of the MMC structure is a three-phase six-arm structure, corresponding to the three phases A, B, and C on the AC side. Each phase includes an upper arm and a lower arm, for a total of six arms. Each arm consists of dozens or even hundreds of sub-modules connected in series (the number of sub-modules determines the number of output levels of the arm). The most commonly used sub-module in industrial applications is the half-bridge sub-module. The main components of the half-bridge sub-module (Half-Bridge SM) include two IGBTs, two anti-parallel diodes, and one energy storage capacitor. In addition to the series-connected sub-modules, each arm must also be equipped with the following auxiliary components: one arm inductor (Arm Inductor, Larm) connected in series in each arm, a bypass switch, a damping resistor (Rdam), etc.

[0028] When installing the valve tower, each individual half-bridge sub-module is assembled and installed on the valve tower support structure of the bridge arm, resulting in a large volume of each bridge arm and a large area occupied.

[0029] In view of this, the embodiments of this application provide a multi-level converter valve structure, which forms a multi-level converter valve structure with fewer components by connecting three switched capacitor valve towers and multiple commutation bridge valve towers in series and parallel. The power device valve strings, capacitor components, power supply components and central control components in the valve modules of the commutation bridge valve towers are all arranged along the second direction, so that the uniformly shaped devices are arranged in rows. Furthermore, the valve structure is installed along the first direction on the module frame, which makes the structural layout of the valve structure more regular and reduces the space occupation. In addition, the central control components are stacked on the power device valve strings, which makes reasonable use of the height space, improves the space utilization rate, and reduces the volume of the entire commutation bridge valve tower.

[0030] The following combination Figures 1 to 6 This paper provides a detailed description of the multilevel converter valve structure of this application.

[0031] like Figures 1 to 4As shown, an embodiment of this application provides a multi-level converter valve structure, including a group of switched capacitor valve towers 100 and multiple commutation bridge valve towers 200. The group of switched capacitor valve towers 100 includes three switched capacitor valve towers 100 with a phase difference; the multiple commutation bridge valve towers 200 are connected in series, and each commutation bridge valve tower 200 is connected in parallel with each switched capacitor valve tower 100. Each commutation bridge valve tower 200 includes multiple bridge modules 210 stacked in series. Each layer of bridge module 210 includes multiple valve modules 211 connected in series. Each valve module 211 includes a power device valve string 201. The capacitor assembly 202, power supply assembly 203, central control assembly 204, and module frame 205 are mounted on the module frame 205 along the first direction X. The central control assembly 204 is disposed on the side of the power device valve string 201 away from the module frame 205 along the stacking direction Z. The power device valve string 201, capacitor assembly 202, power supply assembly 203, and central control assembly 204 are all arranged along the second direction Y. The first direction X, the second direction Y, and the stacking direction Z are perpendicular to each other.

[0032] For example, the stacking direction Z can be the height direction of the valve module 211 or the height direction of the reversing bridge valve tower 200; the first direction X and the second direction Y can be the length direction and width direction of the valve module 211, respectively. As an example, the first direction X is the length direction and the second direction Y is the width direction. The first direction X can be the width direction of the reversing bridge valve tower 200, and the second direction Y can be the length direction of the reversing bridge valve tower 200, or vice versa.

[0033] For example, the phase difference between the three switched capacitor valve towers 100 can be set to a 120° phase difference according to the commutation requirements. In some examples, the shape of the switched capacitor valve tower group 100 can be a cuboid, cube, or irregular columnar structure, wherein the cuboid switched capacitor valve tower group 100 facilitates modular installation and transportation. In some examples, the three switched capacitor valve towers 100 can be arranged at linear intervals or evenly arranged around a circumference.

[0034] In some examples, the switched-capacitor valve tower 100 has a multi-layer structure supported on the ground by insulation. The multi-layer structure includes multiple switched-capacitor modules connected in series. As an example, the switched-capacitor module includes a fully controlled device, a power-consuming element, and a capacitor, wherein the fully controlled device may be an IGBT, IGCT, FET, etc. Exemplarily, the switched-capacitor module may be any one or a combination of bridge module 210, full-bridge module 210, and hybrid module.

[0035] In some examples, the number of commutator bridge valve towers 200 can be the same as the number of switched capacitor valve towers 100; for example, the number of commutator bridge valve towers 200 is three. Exemplarily, the shape of the commutator bridge valve towers 200 can be a cuboid, a cube, or an irregular columnar structure, etc.

[0036] In some examples, each commutator bridge valve tower 200 is connected in parallel with each switched capacitor valve tower 100. The parallel connection can be achieved through busbars, cables, or integrated busbar structures. As an example, the cable parallel connection method specifically involves using high-voltage shielded cables to connect each commutator bridge valve tower 200 to the corresponding switched capacitor valve tower 100, with both ends of the cable fixed by high-voltage connectors.

[0037] For example, the reversing bridge valve tower 200 and the switched capacitor valve tower 100 can be arranged in rows and columns, discretely, or in layers.

[0038] For example, multiple bridge modules 210 are stacked along the height direction of the reversing bridge valve tower 200. In some examples, when stacked along the height direction, adjacent bridge modules 210 are fixed together by support columns and bolts.

[0039] The number of bridge modules 210 can be set according to the power requirements of the reversing bridge valve tower 200. In some examples, each reversing bridge valve tower 200 contains 4, 8, or 16 bridge modules 210 or more.

[0040] For example, the multiple valve modules 211 can be connected in series by means of conductive connectors, welding, or plug-in connection.

[0041] The module frame 205 serves as the mounting base for the valve module 211. In some examples, the module frame 205 can be made of aluminum alloy, stainless steel, or carbon fiber composite material. The carbon fiber composite module frame 205 offers advantages such as light weight and high strength. In some examples, the module frame 205 can be rectangular, square, or irregularly shaped. In some examples, there is only one module frame 205, integrating all components; alternatively, multiple sub-frames can be configured to mount different components separately.

[0042] As an example, the module frame 205 includes two metal beams arranged opposite each other along the second direction Y and an insulating beam connecting the two metal beams, which together form a stable load-bearing structure to support the components.

[0043] In some examples, the power device valve string 201, capacitor assembly 202, and power supply assembly 203 can be mounted on the module frame 205 by means of bolt fixing, snap-fit ​​mounting, or welding.

[0044] In some examples, the central control component 204 can be a PCB circuit board with a metal casing, the metal casing being made of aluminum alloy to achieve electromagnetic shielding. In some examples, the shape of the central control component 204 can be a flat cuboid or a square.

[0045] The central control component 204 is stacked above the power device valve string 201 along its height and can be connected to the power device valve string 201 via an insulating plate. For example, the central control component 204 can be a central control board used to perform submodule-level control, status acquisition, communication interaction, and fault protection, ensuring the stable, safe, and accurate operation of the submodules and the converter as a whole. In some examples, there is only one central control component 204, integrating all control functions; alternatively, it can be configured as multiple sub-control components, each implementing functions such as signal acquisition and drive control.

[0046] In some examples, the power device valve string 201 may have one or more sets, and the central control assembly 204 may be stacked on one or more sets of power device valve strings 201.

[0047] For example, the power device valve string 201 includes a plurality of power devices 206, which can be one or more of IGCTs (integrated gate commutated thyristors) and diodes. In some examples, the power device valve string 201 can be elongated or flat, with the elongated shape facilitating its extension along the second direction Y. In some examples, the number of power device valve strings 201 is one or more, and the multiple power device valve strings 201 can be arranged in parallel to improve current carrying capacity.

[0048] In some examples, capacitor assembly 202 can be an electrolytic capacitor or a film capacitor, with film capacitors offering advantages such as long lifespan and good high-frequency characteristics. In some examples, capacitor assembly 202 can be cylindrical or square, with square capacitor assembly 202 facilitating dense installation. In some examples, there may be one or more capacitor assemblies 202 connected in parallel to increase the capacitance value. Capacitor assembly 202 may have one or more capacitors connected in parallel. As an example, when using a multi-capacitor parallel structure, the multiple capacitors are first fixed to the base plate and then connected to the frame beam; when the capacitors adopt an integral structure, they can be directly connected to the beam of the module frame 205.

[0049] In some examples, the power supply component 203 can be a switching power supply module or a linear power supply module. Switching power supply modules are characterized by high efficiency and small size. In some examples, the shape of the power supply component 203 can be cuboid or flat. In some examples, there is only one power supply component 203, which powers the entire valve module 211. Alternatively, there can be multiple power supply components 203, each powering different components.

[0050] In this embodiment, the power device valve string 201, capacitor assembly 202, power supply assembly 203 and central control assembly 204 in the valve module 211 are all arranged along the second direction Y, so that the devices with uniform shapes are arranged in rows. Furthermore, they are installed along the first direction X on the module frame 205, which makes the structural layout of the valve structure more regular and reduces the space occupation. In addition, the central control assembly 204 is stacked on the power device valve string 201, which makes reasonable use of the height space, improves the space utilization rate, and reduces the volume of the entire reversing bridge valve tower 200.

[0051] refer to Figure 3 and Figure 4 In some embodiments of this application, the power device valve string 201 includes a plurality of power devices 206, a plurality of heat exchangers 207 and a locking assembly 208, wherein each power device 206 and each heat exchanger 207 is alternately arranged along the second direction Y; the locking assembly 208 includes two end plates 213, a tensioning member 216 and an elastic member 212, wherein the plurality of power devices 206 and the plurality of heat exchangers 207 are located between the two end plates 213, the two end plates 213 are connected by the tensioning member 216, and the elastic member 212 abuts against at least one end plate 213 and the power device 206.

[0052] In some examples, the power device 206 can be in the shape of a square chip package or a circular package, with the square chip package facilitating dense arrangement; in some examples, the number of power devices 206 can be set to 2, 4, 8 or 11 depending on the power requirements, with multiple power devices 206 connected in series to improve the withstand voltage level.

[0053] The heat exchanger 207 is used for heat dissipation of the power device 206. In some examples, the heat exchanger 207 can be an aluminum alloy heat sink, a copper heat pipe, a water-cooled heat sink, etc. In some examples, the shape of the heat exchanger 207 can be flat, finned, corrugated, etc. As an example, the heat exchanger 207 is located between two power devices 206.

[0054] In some examples, the alternating arrangement of power device 206, heat exchanger 207, and power device 206 specifically involves setting a heat exchanger 207 between two adjacent power devices 206, with the contact surface of the heat exchanger 207 and the power device 206 in close contact.

[0055] In one example, the valve module 211 is provided with a heat exchange pipe at one end along the first direction X, which facilitates the entry and exit of the heat exchange medium on one side, making the overall structure more compact.

[0056] In some examples, the locking assembly 208 can be a frame-type or symmetrical structure, with the symmetrical structure ensuring uniform locking force. In some examples, there are one or more locking assemblies 208, with each locking assembly 208 corresponding to a combination of a power device 206 and a heat exchanger 207.

[0057] In some examples, the end plate 213 can be made of stainless steel or aluminum alloy with an insulating coating on its surface. In some examples, the end plate 213 can be square or circular, with the square end plate 213 fitting the square package of the power device 206. In some examples, the tensioning member 216 can be made of high-strength bolts, tie rods, or cables; high-strength bolts are suitable for rigid locking scenarios. In some examples, the tensioning member 216 can be cylindrical or threaded rod-shaped. In some examples, there are four, six, or eight tensioning members 216, evenly distributed circumferentially along the end plate 213 to ensure uniform locking force. In some examples, the elastic member 212 can be made of springs, elastic rubber pads, or disc springs; disc springs have the advantages of high load-bearing capacity and small deformation. In some examples, the elastic member 212 can be cylindrical, disc-shaped, or annular; in some examples, there are one or more elastic members 212, evenly arranged circumferentially along the end plate 213.

[0058] In this embodiment, by alternating the arrangement of power devices 206 and heat exchangers 207 along the second direction Y, efficient heat dissipation of power devices 206 can be achieved, preventing damage to power devices 206 due to overheating. With the cooperation of the two end plates 213, tensioning member 216 and elastic member 212 of locking assembly 208, multiple power devices 206 and heat exchangers 207 can be firmly locked together. At the same time, elastic member 212 can provide a buffering effect to compensate for structural deformation caused by temperature changes, ensuring the tight fit between power devices 206 and heat exchangers 207, further improving heat dissipation reliability and overall structural stability.

[0059] refer to Figure 3 Furthermore, in some optional embodiments of this application, the plurality of power device valve strings 201 include an integrated gate commutated thyristor valve string 201a and a diode valve string 201b. Along the first direction X, the integrated gate commutated thyristor valve string 201a is located on one side of the diode valve string 201b; the central control component 204 is disposed on the diode valve string 201b along the stacking direction Z.

[0060] The integrated gate-commutated thyristor valve string 201a serves as a controllable switching unit. In some examples, the core material consists of an integrated gate-commutated thyristor chip and copper conductive connectors, with the chip made of silicon-based material. In some examples, the integrated gate-commutated thyristor valve string 201a can be elongated or flat, with the elongated shape adapting to an extension along the second direction Y. In some examples, there are multiple integrated gate-commutated thyristor valve strings 201a.

[0061] The diode valve string 201b serves as a unidirectional conductive unit. In some examples, the core material of the diode valve string 201b consists of a diode chip and a conductive material, with the conductive material being copper or aluminum. In some examples, the diode valve string 201b can be elongated or block-shaped. In some examples, there are multiple diode valve strings 201b.

[0062] In some examples, along the first direction X, the integrated gate-commutated thyristor valve string 201a is located on one side of the diode valve string 201b, and the two are separated by an insulating partition.

[0063] In other examples, along the first direction X, the integrated gate-commutated thyristor valve string 201a and the diode valve string 201b are arranged adjacent to each other, so that their current loops need to be as short and narrow as possible. Adjacent arrangement shortens the length of the connecting busbar and reduces the loop area. Parasitic inductance is positively correlated with loop length and area, thus minimizing parasitic inductance and avoiding overvoltage damage. Adjacent arrangement can control parasitic inductance to the level of benahens (nH), significantly reducing the risk of overvoltage. High-frequency switching current generates electromagnetic radiation (EMI) in the loop. Adjacent arrangement reduces the current loop area of ​​the main circuit, which is equivalent to reducing the size of the EMI radiating antenna, reducing electromagnetic interference to the central control component 204 without requiring additional shielding measures, thus reducing cost and size.

[0064] In some examples, when the stacking direction Z is the height direction, each central control board in the central control assembly 204 is fixed to the top of the diode valve string 201b by an insulating bracket, which is made of insulating material.

[0065] In some examples, the central control assembly 204 includes multiple central control boards arranged sequentially along the second direction Y. The outer shell of the central control boards is made of a metal material with electromagnetic shielding properties. There is a voltage difference between the central control boards corresponding to each power device, therefore each central control board has an insulating gap and / or is provided with insulating elements between itself and adjacent central control boards, as well as between itself and the bottom heat exchange component, for insulation.

[0066] As an example, the central control assembly 204 is mounted on an insulating tray, meaning each central control board is mounted on the insulating tray via an insulating bracket. The insulating tray maintains a distance of more than 70mm from the diode valve string 201b to ensure air insulation. A distance of more than 40mm is maintained between adjacent central control boards to meet insulation and corona prevention requirements. The creepage path consists of an insulating bracket-insulating tray-insulating bracket, with a minimum creepage distance of 150mm between adjacent central control boards to ensure sufficient creepage distance.

[0067] In this embodiment, by setting multiple power device valve strings 201 as a combination of integrated gate-commutated thyristor valve strings 201a and diode valve strings 201b, controllable conduction and unidirectional freewheeling functions of multi-level commutation can be achieved. Arranging the integrated gate-commutated thyristor valve string 201a on one side of the diode valve string 201b along the first direction X makes the arrangement of the two valve strings neat, facilitating wiring and heat dissipation. Placing the central control component 204 along the stacking direction Z on the diode valve string 201b fully utilizes the space above the diode valve string 201b, further optimizing the spatial layout of the valve module 211 and improving space utilization.

[0068] In some embodiments, the capacitor assembly 202 includes a capacitor, a connecting busbar, and a support. The capacitor assembly 202 is disposed along a first direction X on the side of the integrated gate commutated thyristor valve string 201a opposite to the diode valve string 201b, and the capacitor is connected to the valve string via the busbar.

[0069] Furthermore, in some embodiments of this application, the diode valve string 201b is located at one end of the valve module 211 along the first direction X.

[0070] In some examples, the diode valve string 201b is located on the side of the valve module 211 near the input terminal of the valve module 211, facilitating connection to external input lines. Exemplarily, the diode valve string 201b can be fixed to the end of the valve module 211 by bolts or snap-fit.

[0071] In this embodiment, the diode valve string 201b is arranged at one end of the valve module 211 along the first direction X. This allows the diode valve string 201b to be kept away from other heat-generating components inside the valve module 211, reducing thermal interference. At the same time, it facilitates the individual inspection and replacement of the diode valve string 201b, improving the maintenance convenience of the valve module 211. In addition, the end arrangement can also optimize the wiring path inside the valve module 211, shorten the length of the input and output lines, and reduce line loss.

[0072] In some embodiments, along the first direction X, the diode valve string 201b, the integrated gate commutated thyristor valve string 201a, the capacitor assembly 202, and the power supply assembly 203 are arranged sequentially. The distance between the integrated gate commutated thyristor valve string 201a and the capacitor assembly 202 along the first direction X is 100mm-150mm.

[0073] When the integrated gate commutated thyristor and diode are working, the potential difference is large. The capacitor assembly 202 itself also carries a DC high voltage. The capacitor assembly 202 is located on one side of the integrated gate commutated thyristor valve string 201a to avoid forming a high voltage triangle in the middle, and to avoid increasing the spacing and wasting space because the creepage distance and electrical clearance must meet the insulation requirements of all three at the same time. In addition, it avoids the metal casing of the capacitor assembly 202 from becoming the medium of electric field coupling and causing partial discharge. The distance between the integrated gate commutated thyristor valve string 201a and the capacitor assembly 202 along the first direction X is 100mm-150mm.

[0074] In some embodiments, the valve module 211 further includes a clamping diode disposed on a heat exchanger 207 within the integrated gate commutated thyristor valve string 201a. The capacitor assembly 202 is arranged adjacent to the clamping diode, with a spacing of 100mm-150mm between them, which effectively reduces stray inductance of the clamping circuit and improves module reliability. Exemplarily, the spacing between the capacitor assembly 202 and the clamping diode is 120mm. The connecting busbars of the capacitor assembly 202 and the clamping diode are arranged in pairs closely together.

[0075] In other examples, valve module 211 also includes a voltage equalizing resistor disposed on heat exchanger 207. This heat exchanger 207 can be located within integrated gate commutated thyristor valve string 201a or within diode valve string 201b.

[0076] In some embodiments, the module frame 205 includes two first support beams 217 spaced apart along a second direction Y, a plurality of second support beams 218 arranged along a third direction Z, a third support beam 221, and an insulating beam 219. The second support beams 218 are connected to the first support beams 217, the insulating beam 219 is connected between the two first support beams 217 and the second support beams 218 along the second direction Y, and the third support beam 221 is disposed on the insulating beam 219.

[0077] Along the second direction Y, the power device valve string 201 is disposed on both sides of the third support beam, and the capacitor assembly 202 and the power supply assembly 203 are connected to the second support beam.

[0078] refer to Figure 2 and Figure 5 In some optional embodiments of this application, the bridge module 210 includes a first switch module 214 and a second switch module 215 arranged at intervals. Both the first switch module 214 and the second switch module 215 have multiple valve modules 211. Along the stacking direction Z, two adjacent first switch modules 214 are connected in series to form a first bridge arm 220. Along the stacking direction Z, two adjacent second switch modules 215 are connected in series to form a second bridge arm 230.

[0079] In some examples, the spacing is 5cm, 10cm, or 15cm. In some examples, the spacing method can be through insulating partitions or through air gaps. Insulating partition spacing can improve insulation reliability and is suitable for high-voltage scenarios.

[0080] In some examples, there are one or more first switch modules 214 and second switch modules 215. For example, multiple first switch modules 214 are set at intervals corresponding to multiple second switch modules 215.

[0081] In some examples, when connected in series, adjacent first switch modules 214 are aligned either directly or staggered along the stacking direction Z. Direct alignment facilitates wiring and fixing. The second switch module 215 is configured similarly.

[0082] For example, the series connection method can be through series connection of busbars, series connection of cables, etc.

[0083] In this embodiment, the bridge module 210 is provided with a first switch module 214 and a second switch module 215 arranged at intervals, which can avoid electromagnetic interference and thermal interference between the two and improve the working stability. Adjacent first switch modules 214 are connected in series along the stacking direction Z to form a first bridge arm 220 and adjacent second switch modules 215 are connected in series to form a second bridge arm 230, which can improve the withstand voltage and power rating of the bridge module 210, adapt to the high voltage requirements of the multi-level converter valve structure, and at the same time, the stacked series method can make full use of vertical space and further optimize the spatial layout of the commutation bridge valve tower 200.

[0084] Specifically, in one embodiment of this application, two adjacent first bridge arms 220 are connected in series along the stacking direction Z to form a third bridge arm; two adjacent second bridge arms 230 are connected in series along the stacking direction Z to form a fourth bridge arm; the third bridge arm and the fourth bridge arm are connected in parallel.

[0085] For example, the series connection method can be through busbar connection or integrated bus structure connection. In some examples, the series connection through busbar specifically means that the top output end and bottom input end of two adjacent first bridge arms 220 are connected through a high-voltage busbar. The busbar is made of copper and is provided with insulating support. In some examples, the spacing between adjacent first bridge arms 220 is consistent with the stacking spacing of bridge modules 210 during series connection to ensure the regularity of the structure.

[0086] For example, the parallel connection can be achieved through parallel connection of busbars or branch cables. In some examples, the parallel connection point is located in the middle or at the end of the third and fourth arms.

[0087] In this embodiment, adjacent first bridge arms 220 are connected in series to form a third bridge arm, and adjacent second bridge arms 230 are connected in series to form a fourth bridge arm along the stacking direction Z. This can further improve the withstand voltage level of the bridge arms and adapt to the structural requirements of multi-level converter valves with higher voltage levels. Connecting the third bridge arm and the fourth bridge arm in parallel can improve the current carrying capacity of the converter circuit.

[0088] refer to Figure 1 In some optional embodiments of this application, three switched capacitor valve towers 100 are arranged at intervals M along the row direction, and multiple commutator bridge valve towers 200 are arranged at intervals M along the row direction, with each commutator bridge valve tower 200 arranged opposite to each switched capacitor valve tower 100.

[0089] For example, the row direction M can be either the first direction X or the second direction Y, and the column direction N can be the other.

[0090] In some examples, the spaced arrangement is fixed to the mounting base via a bottom bracket made of concrete or metal.

[0091] Multiple reversing bridge valve towers 200 are arranged at intervals M along the row direction, with the spacing pattern consistent with that of the switched capacitor valve towers 100, which can be linear or uniform. In some examples, the spacing between the reversing bridge valve towers 200 and the switched capacitor valve towers 100 is the same to ensure the regularity of the overall layout.

[0092] The relative arrangement can be a direct arrangement, a staggered relative arrangement, etc. In some examples, the direct arrangement specifically means that the central axis of each reversing bridge valve tower 200 coincides with the central axis of the corresponding switched capacitor valve tower 100, which facilitates the wiring connection between the two and shortens the connection distance.

[0093] In some examples, the DC input terminals of both the switched capacitor valve tower 100 and the commutator bridge valve tower 200 are located at the bottom of the valve tower, while the DC output terminals are located at the top of the valve tower. As an example, the DC output terminals can be led out through the equalizing ring 260 at the top of the valve tower.

[0094] For example, DC output terminals and DC output terminals are respectively provided along the length direction of the switched capacitor valve tower 100 and the commutation bridge valve tower 200.

[0095] In another example, an AC terminal is provided between two adjacent first arms 220 or two adjacent second arms 230 of the reversing bridge valve tower 200. The AC terminal is located on the side of the reversing bridge valve tower 200 away from the capacitor shut-off valve tower 100.

[0096] In this embodiment, the three switched capacitor valve towers 100 and the multiple commutation bridge valve towers 200 are arranged at intervals along the row direction M, making the overall layout of the multi-level converter valve structure regular and facilitating modular installation and maintenance. The commutation bridge valve towers 200 and the switched capacitor valve towers 100 are arranged opposite each other, which can shorten the length of the connection line between them, reduce the line impedance and loss, and at the same time facilitate the centralized layout and management of the lines, thereby improving the integration of the converter system.

[0097] refer to Figure 2 and Figure 7 In some embodiments, the switched capacitor valve tower 100 and the reversing bridge valve tower 200 both have conventional configuration structures such as insulators 240, shields 250, equalizing rings 260, interlayer insulation components 270, and cooling water pipes 280.

[0098] Furthermore, in some embodiments of this application, multiple commutator bridge towers 200 are located on one side of three switched capacitor towers 100 along the column direction N.

[0099] For example, both the switched capacitor valve tower 100 and the reversing bridge valve tower 200 are supported valve tower structures, which are supported on the ground by insulators 240.

[0100] In this embodiment, multiple commutator bridge valve towers 200 are located on one side of three switched capacitor valve towers 100 along the column direction N, forming a regular layout with alternating rows and columns. This can effectively utilize the installation space and reduce the overall footprint of the multi-level converter valve structure. At the same time, the same-side arrangement facilitates the wiring connection between the commutator bridge valve towers 200 and the switched capacitor valve towers 100, reduces wiring intersections, and improves the rationality and safety of the wiring layout.

[0101] refer to Figure 6 and Figure 7 In another optional embodiment of this application, a plurality of commutator bridge valve towers 200 are located on one side of three switched capacitor valve towers 100 along the stacking direction Z.

[0102] In one example, the switched capacitor valve tower 100 and the reversing bridge valve tower 200 are respectively a supported valve tower structure and a suspended valve tower structure.

[0103] In another example, the stacked fixing method between the reversing bridge valve tower 200 and the switched capacitor valve tower 100 can be fixing by a metal bracket or fixing by an insulating tie rod. Fixing by an insulating tie rod can achieve electrical isolation and improve safety.

[0104] In this embodiment, multiple commutation bridge valve towers 200 are located on one side of three switched capacitor valve towers 100 along the stacking direction Z. This can make full use of the height space, significantly reduce the horizontal area occupied by the multi-level converter valve structure, and adapt to narrow installation scenarios. At the same time, the stacked arrangement can bring the commutation bridge valve towers 200 and the switched capacitor valve towers 100 closer together, further shortening the connection line length, reducing line loss, and improving converter efficiency.

[0105] In one specific embodiment of this application, the switched capacitor valve tower 100 is a supported valve tower structure, and the reversing bridge valve tower 200 is a suspended valve tower structure.

[0106] In some examples, the support method of the supported valve tower structure can be bottom support. Specifically, the bottom support is that the bottom of the switched capacitor valve tower 100 is provided with support feet (insulators 240). The support feet are fixed to the installation foundation by expansion bolts. The support feet are made of high-strength aluminum alloy and the bottom of the support feet is provided with anti-slip insulating pads made of rubber, which can improve the stability of the support and achieve electrical isolation.

[0107] In some examples, the equalizing ring 260 at the top of the commutator bridge valve tower 200 is located at the end of the switched capacitor valve tower 100 away from the ground.

[0108] refer to Figure 6 In some examples, the suspension method of the suspended valve tower structure can be top suspension. In some examples, top suspension specifically means that the top of the reversing bridge valve tower 200 is equipped with lifting lugs (insulators 240), with two or four lifting lugs evenly distributed along the circumference of the top frame. The lifting lugs are fixed to the load-bearing structure at the top of the installation by lifting beams and bolts.

[0109] In this embodiment, the switched capacitor valve tower 100 adopts a supported valve tower structure, which ensures the stability of its own structure, can stably support the weight of internal components, and is suitable for the installation requirements of high-power components; the commutator bridge valve tower 200 adopts a suspended valve tower structure, which can further utilize the idle space at the top and form a staggered layout with the supported switched capacitor valve tower 100, maximizing the space utilization rate; at the same time, the suspended structure can reduce the pressure of the commutator bridge valve tower 200 on the bottom mounting foundation, reduce the foundation construction cost, and facilitate the utilization and maintenance of the space below the commutator bridge valve tower 200.

[0110] In offshore converters, due to limited installation space and ease of hoisting, the commutator bridge valve tower 200 adopts a suspended valve tower structure. The overlapping area of ​​the switched capacitor valve tower 100 and the commutator bridge valve tower 200 along the stacking direction Z is between 80% and 100%, thereby improving space utilization and reducing the occupancy of installation space.

[0111] The above are merely specific embodiments of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A multi-level converter valve structure, characterized in that, include: A switched capacitor valve tower group, comprising three switched capacitor valve towers with a phase difference; Multiple commutator bridge valve towers are connected in series, and each commutator bridge valve tower is connected in parallel with each switched capacitor valve tower. Each commutator bridge valve tower includes multiple bridge modules stacked on top of each other. Each bridge module includes multiple valve modules connected in series. Each valve module includes a power device valve string, a capacitor assembly, a power supply assembly, a central control assembly, and a module frame. The power device valve string, the capacitor assembly, and the power supply assembly are mounted on the module frame along a first direction. The central control assembly is disposed on the side of the power device valve string away from the module frame along the stacking direction. The power device valve string, the capacitor assembly, the power supply assembly, and the central control assembly all extend along a second direction. The first direction, the second direction, and the stacking direction are perpendicular to each other.

2. The multilevel converter valve structure according to claim 1, characterized in that, The power device valve string includes multiple power devices, multiple heat exchange components, and a locking assembly, with each power device and each heat exchange component alternately arranged along the second direction; The locking assembly includes two end plates, a tensioning member, and an elastic member. The plurality of power devices and the plurality of heat exchangers are located between the two end plates. The two end plates are connected by the tensioning member, and the elastic member abuts against at least one of the end plates and the power device.

3. The multilevel converter valve structure according to claim 1, characterized in that, The plurality of power device valve strings include integrated gate-commutated thyristor valve strings and diode valve strings, wherein along the first direction, the integrated gate-commutated thyristor valve strings are located on one side of the diode valve strings; The central control component is disposed on the diode valve string along the stacking direction.

4. The multilevel converter valve structure according to claim 3, characterized in that, The diode valve string is located at one end of the valve module along the first direction.

5. The multilevel converter valve structure according to any one of claims 1 to 4, characterized in that, The bridge module includes a first switch module and a second switch module arranged at intervals. Both the first switch module and the second switch module have multiple valve modules. Along the stacking direction, two adjacent first switch modules are connected in series to form a first bridge arm. Along the stacking direction, two adjacent second switch modules are connected in series to form a second bridge arm.

6. The multilevel converter valve structure according to claim 5, characterized in that, Along the stacking direction, two adjacent first bridge arms are connected in series to form a third bridge arm; Along the stacking direction, two adjacent second bridge arms are connected in series to form a fourth bridge arm, and the third bridge arm and the fourth bridge arm are connected in parallel.

7. The multilevel converter valve structure according to any one of claims 1 to 4, characterized in that, The three switched capacitor valve towers are arranged at intervals along the row direction, and the plurality of commutator bridge valve towers are arranged at intervals along the row direction, with each commutator bridge valve tower arranged opposite to each of the switched capacitor valve towers.

8. The multilevel converter valve structure according to claim 7, characterized in that, Multiple of the aforementioned reversing bridge valve towers are located on one side of the three switched capacitor valve towers along the column direction.

9. The multilevel converter valve structure according to claim 7, characterized in that, The plurality of the reversing bridge valve towers are located on one side of the three switched capacitor valve towers along the stacking direction.

10. The multilevel converter valve structure according to claim 9, characterized in that, The switched capacitor valve tower is a supported valve tower structure, and the reversing bridge valve tower is a suspended valve tower structure.

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