Converter valve assembly

Abstract

Disclosed herein is a converter valve assembly (20) for a power grid system, comprising two or more equal groups (6a, 6b, 6c) of prismatic converter cells (3a-j), each group (6a, 6b, 6c) arranged in a respective one of a plurality of parallel planes (7a, 7b, 7c) spaced apart along an axis (8). The converter cells (3a-j) in a group (6a) are connected in series and arranged with their shortest dimensions perpendicular to the plane (7a), and the groups (6a, 6b, 6c) are connected in series along the axis (8). The prismatic converter cells (3a-j) in a group (6a) are arranged such that, during operation of the converter valve assembly (20), a corresponding voltage difference exists between each converter cell (3a-j) in the group (6a) and each corresponding converter cell (3k-t) in the adjacent group (6b) that is spatially closest to the converter cell (3a-j). Therefore, the spacing between the groups can be reduced, reducing the overall volume of the converter valve assembly.

Description

[Technical Field]

[0001] This disclosure relates to power systems. More specifically, this disclosure relates to converter valve assemblies for power grid systems and methods for manufacturing converter valve assemblies.

[0002] background The power distribution network includes converters. These converters are operated to convert an input power source voltage (e.g., from a power generation source such as a wind turbine) into an output grid voltage for distribution to the power grid. In some cases, the converters can also convert an alternating current (AC) input to a direct current (DC) output, for example, for the high-voltage DC (HVDC) portion of the power grid, or vice versa, for example, for the AC portion of the power grid.

[0003] A converter comprises valve assemblies (also called "valves"), each valve assembly containing multiple converter cells. Each converter cell typically contains a full-bridge or half-bridge inverter circuit and contributes a certain unit of voltage toward the converter's total possible output voltage. The number of valve assemblies and / or converter cells may be selected based on the output voltage required by the converter.

[0004] These valve assemblies are typically housed in valve holes. In high-voltage applications such as power grid applications, high voltages may be present within the valve holes, and therefore it is crucial to ensure that the risk of electric arc discharge within the valve holes is minimized. Furthermore, the size of the valve holes may be limited. This is especially true in offshore winds, where the cost per unit volume of offshore platforms is typically much higher than that of onshore valve holes. Therefore, valve assemblies may need to be configured to be located as close to each other as possible.

[0005] Taking these limitations into consideration, it is desirable to optimize the arrangement of the converter valves within the valve holes.

[0006] overview As part of this disclosure, it is recognized that optimized, or at least improved, arrangement configurations of converter valves can be achieved at least in part by improving the relative arrangement configuration of converter cells to reduce or equalize voltage differences between spatially adjacent components, and the term “spatially” is used to distinguish it from “electrically” adjacent components.

[0007] Each converter cell within the valve assembly is connected in series, and the entire output voltage of the converter is the same voltage unit V. cell It can be considered that each converter cell contributes to the V of the previous converter cell connected in series with it. cell It has a voltage difference ΔV.

[0008] As part of this disclosure, when determining the spatial arrangement configuration of converter cells, it is recognized that it is preferable to minimize this ΔV in order to reduce the risk of electric arc discharge between converter cells and to enable the converter cells to be arranged as close to each other as possible, thereby minimizing (or at least reducing) the overall volume of the valve assembly.

[0009] Furthermore, as part of this disclosure, it is recognized that a uniform distribution of voltage differences between spatially adjacent converter cells also reduces the risk of electric arc discharge between converter cells in a valve assembly.

[0010] Accordingly, according to one aspect of the present disclosure, a converter valve assembly for a power grid system is provided, comprising two or more equal groups of prismatic converter cells. That is, each group (or at least two groups) of prismatic converter cells in the converter valve assembly comprises the same number N of prismatic converter cells. As used herein, a “prismatic” converter cell is a converter cell having a three-dimensional form factor having length, width, and height, comprising a pair of parallel faces separated by the shortest dimensions of the length, width, and height. For example, the prismatic form factor may include a rectangular parallelepiped form factor, a triangular prism form factor, or a cylindrical form factor.

[0011] Each of two or more groups is arranged (i.e., spatially arranged) within the respective planes of a plurality of parallel planes spaced apart along a certain axis. The converter cells may be positioned and held in place by any suitable support structure, the preferred configuration of such a support structure will be described later.

[0012] It will be understood that the "plane" on which the converter cells are arranged can only be defined by the arrangement after it has been made. That is, two or more converter cells may be arranged relative to each other such that a plane intersecting all of the two or more converter cells is defined.

[0013] Furthermore, although a "parallel" plane is referenced, it will be understood that a certain degree of tolerance from perfect parallelism outward is acceptable without significantly degrading the advantageous characteristics of the converter valve device of this disclosure.

[0014] The converter cells within the group are connected in series (electrically) and arranged so that their shortest dimensions are perpendicular to the plane. The electrical connections between the converter cells may be made by any suitable means, and the groups are then connected in series along the axes, for example, using similar means for electrical connections.

[0015] The minimum dimension of a prismatic converter cell may be the length, width, or height of the smallest three-dimensional converter cell. For example, if the converter cell has a cubic form factor with a length of 30 centimeters (cm), a width of 20 cm, and a height of 10 cm, the converter cell in the converter valve assembly of this disclosure is configured to be positioned at a height perpendicular to the plane, i.e., the plane defined by the relative arrangement configuration of the converter cell. In this example, the length and width of the converter cell extend parallel to the plane.

[0016] The relative arrangement of converter cells in a plane with respect to other groups in parallel planes can, advantageously, be configured to normalize the voltage difference between the planes of each group. Thus, the prismatic converter cells in a group are arranged such that, during the operation of the converter valve assembly, there exists a corresponding voltage difference (i.e., the same or substantially similar) between each converter cell in the group and each corresponding converter cell in the adjacent group that is spatially closest to the aforementioned converter cell.

[0017] From another perspective, each converter cell within a group has a corresponding converter cell in the adjacent group that is spatially closest to the converter cell, and the voltage difference between each converter cell in a group and its corresponding converter cell in the adjacent group is the same during the operation of the converter valve assembly. That is, the prismatic converter cells within a group are arranged and configured such that there is a corresponding voltage difference between any pair of converter cells, the first converter cell of any pair being the converter cell of the group, and the second converter cell of the pair being the corresponding converter cell in the adjacent group that is spatially closest to the first converter cell during the operation of the converter valve assembly.

[0018] Such an arrangement configuration may be achieved, for example, by connecting each group in series from the first converter cell to the last converter cell of a group, according to a cell arrangement configuration common to all groups. In such an example, the last converter cell of a group may be connected to the first converter cell of an adjacent group.

[0019] The spacing between different groups of converter cells arranged in different adjacent planes can be determined at least in part on the risk of electric arc discharge between conductors in different groups having different potential differences. The greater the potential difference between conductors (for example, during the operation of a converter valve assembly), the greater the distance that should be provided between the conductors to mitigate the aforementioned risk of electric arc discharge between them.

[0020] Therefore, by arranging (or optimizing) the converter cells so that a corresponding voltage difference (i.e., the same or substantially similar) exists between each converter cell in a group and each corresponding converter cell in the adjacent group that is spatially closest to each converter cell during the operation of the converter valve assembly, the spacing between adjacent groups can be reduced (or optimized), and no space is wasted within the converter valve assembly.

[0021] Furthermore, by arranging and configuring the converter cells so that their shortest dimensions are perpendicular to the plane, it can be ensured that the spacing between groups (along an axis perpendicular to the plane) is less constrained by the dimensions of the converter cells themselves. For example, the spacing S may be determined based on the voltage difference between converter cells in adjacent groups, and this voltage difference may be substantially the same and uniform across the entire plane in which the converter cells are arranged.

[0022] For example, the spacing S may be the minimum spacing between the groups that reduces the risk of electric arc discharge between the groups. The spacing S may be smaller than the longest dimension L of the converter cell such that H < S < L, but may be larger than the shortest dimension H of the converter cell. Therefore, by arranging and configuring the converter cells with the shortest dimension H perpendicular to the plane, the spacing between the groups (i.e., between the planes) can be reduced based on electrical limitations rather than spatial limitations.

[0023] By optimizing the volume occupied by the converter valve assembly, the overall footprint of the converter station can be reduced. This can be particularly beneficial when the converter station is installed in an offshore wind facility due to the very high costs and spatial limitations associated with such facilities.

[0024] In some examples, the cell arrangement configuration may be, for example, a spiral arrangement configuration when viewed with respect to electrical connections between cells within a group and between groups, for example, a horizontal spiral in which the axis of the spiral extends horizontally. In other words, the cell arrangement configuration can include arranging the converter cells within a group around an axis and connecting the converter cells within the group in order according to their radial positions around the axis, thereby forming an open loop from the first converter cell to the last converter cell of the group. Each open loop can be seen as forming a spiral-shaped "turn".

[0025] According to such an arrangement configuration, the conductors used to connect the cells within the group and interconnect the groups can be shortened. Further, the configuration of the electromagnetic field during the operation of the converter valve assembly can be made more uniform, for example, to further reduce the risk of electric arc discharge along the path of a concentrated electric field.

[0026] Furthermore, according to some examples, each converter cell within a group may be positionally aligned with a corresponding converter cell in an adjacent group, and the corresponding converter cells have the same position within the cell arrangement configuration.

[0027] Therefore, not only is the spacing along the axis reduced, but it is also perpendicular to the axis, which further reduces the overall volume of the converter valve assembly, and as a result, the absolute distance between corresponding pairs of converter cells (which have the same respective positions in the arrangement configuration) can be reduced or minimized.

[0028] As described above, multiple parallel planes can be spaced apart along the axis by an amount corresponding to the voltage difference between each converter cell in a group and each corresponding converter cell in an adjacent group. That is, a minimum "safe" distance can be calculated based on the voltage difference between corresponding converter cells in adjacent groups, and the groups can be spaced apart by this minimum safe distance, thereby reducing the overall volume of the converter valve assembly.

[0029] As part of this disclosure, it is understood that earthquakes and other seismic events pose significant risks to converter valve assemblies. Therefore, in some examples, each group may be rigidly mounted to its respective substructure. This prevents converter cells within the same group from moving relative to each other during earthquake-related events, thereby reducing the risk of electrical arc discharge within the group or adverse effects on the operation of the group of converter cells.

[0030] In some further examples, each substructure can be rigidly connected along its axis, thereby forming a support structure for the converter valve assembly. This prevents different groups from moving relative to one another during earthquake-related events, thereby reducing the risk of electrical arc discharge between groups or adverse effects on the operation of the converter valve assembly. The substructures may also be rigidly connected by insulating members to further enhance electrical insulation between groups.

[0031] The converter valve assembly may further comprise a mounting assembly for a support structure. The mounting assembly may comprise a suspension assembly for suspending the support structure from the ceiling, or a stand assembly for raising the support structure from the floor.

[0032] By suspending the support structure from the ceiling of the valve hole, seismic motion can be absorbed or mitigated by the swinging or other compensatory motion of the suspended support structure, thus reducing the risk imposed on the structure of the converter valve assembly by seismic events.

[0033] On the other hand, if the support structure is attached to the stand assembly, installation may be simpler and access to the converter valve assembly may be improved.

[0034] Such a stand assembly may comprise multiple posts configured to provide electrical insulation from the floor, and each substructure may be mounted to one or more posts, or alternatively, multiple substructures may be mounted via a common mounting structure.

[0035] To reduce the risk of electric arc discharge or other electromagnetic interference between the converter valve assembly and external hazards (e.g., walls, columns, other electrical components, etc.), a shielding structure such as a corona shield may be provided.

[0036] In some examples, the shielding structure may be provided for each group arranged in a plane. Such an arrangement can advantageously reduce the overall amount of shielding required to shield the converter valve assembly from the external environment, and vice versa.

[0037] In a preferred embodiment, the converter valve assembly can constitute an arm of the converter. That is, two or more groups of converter cells constituting the converter valve assembly can include all of the converter cells in the entire arm of the converter. Thus, the arm may advantageously be formed as a single unit, and therefore may have a single structure. Compared to comparative examples in which multiple separate structures, each forming a “sub-arm”, are used to constitute the arm of the converter, a system that is advantageously robust, particularly with respect to earthquake-related events, is provided. The converter may be, for example, a modular multilevel converter configured to supply power to a power grid.

[0038] A further aspect of the present disclosure provides a method for manufacturing a converter valve assembly substantially as described above. The method involves arranging two or more equal groups of prismatic converter cells such that each group is arranged in the plane of a plurality of parallel planes spaced apart along the axis. As a result of such arrangement, the converter cells in the groups are connected in series and arranged such that their shortest dimensions are perpendicular to the plane, and each group is connected in series along the axis, and the arrangement of the prismatic converter cells in the groups is configured such that, during the operation of the converter valve assembly, there exists a corresponding voltage difference between each converter cell in the group and each corresponding converter cell in the adjacent group that is spatially closest to each converter cell.

[0039] This method can be carried out by any manual or automated means, such as the use of a computer-controlled manipulator, which can provide better accuracy than can be achieved manually.

[0040] In any case, it will be understood that many advantages are offered by providing a converter valve assembly that is formed as a series of parallel planes and allows these planes to be separated from each other according to a common voltage difference for all corresponding pairs of converter cells in an adjacent group. Some of these advantages have been described above, and some may be revealed in the following further description of specific embodiments of the present disclosure.

[0041] Brief explanation of the drawing One or more embodiments are described only as examples, with reference to the accompanying drawings. [Brief explanation of the drawing]

[0042] [Figure 1] This is an electrical circuit diagram of an exemplary modular multilevel converter (MMC). [Figure 2] This is an electrical circuit diagram of an exemplary converter cell configured as a full-bridge submodule. [Figure 3] This is a schematic perspective view of a prismatic converter cell according to an embodiment of the present disclosure. [Figure 4a] This is a perspective view of a portion of a conventional converter valve assembly. [Figure 4b] This is a top view of a portion of a conventional converter valve assembly. [Figure 5a] This is an exploded perspective view of a converter valve assembly according to one embodiment of the present disclosure. [Figure 5b] This is a top view of one of the converter cell groups shown in Figure 5a. [Figure 6] This is a perspective view of a converter valve assembly according to one embodiment of the present disclosure. [Figure 7] This is a perspective view of a converter valve assembly having a shield structure and a mounting assembly according to one embodiment of the present disclosure. [Figure 8a]This figure shows possible alternative configurations for the mounting assembly according to embodiments of the present disclosure. [Figure 8b] This figure shows possible alternative configurations for the mounting assembly according to embodiments of the present disclosure. [Figure 9] This is a perspective view of a part of the support structure for a converter valve assembly according to one embodiment of the present disclosure. [Figure 10] This is a perspective view of a converter valve assembly constituting the arm of a converter according to one embodiment of the present disclosure. [Figure 11] This figure illustrates an exemplary step flow of a method for manufacturing a converter valve assembly according to one embodiment of the present disclosure. [Modes for carrying out the invention]

[0043] Detailed explanation This disclosure is described below with several illustrative examples. These examples are provided for illustrative and illustrative purposes only and are not intended to limit the scope of this disclosure.

[0044] Using the same reference numerals in different figures may indicate that the mentioned component or element is the same or similar in terms of its function in at least the different figures mentioned above. Therefore, a discussion of such the same or similar component or element may not be repeated in all figures in which the component or element is shown.

[0045] Figure 1 shows an electrical circuit diagram of an exemplary modular multilevel converter (MMC) 1. The MMC 1 may act as a voltage source converter for a power grid and may have a source voltage V that is alternating current (AC) or direct current (DC). S The grid voltage V may be AC ​​or DC. gIt may operate to convert. For example, the power grid where the MMC1 is installed may be a high-voltage DC (HVDC) power grid.

[0046] Power supply voltage V S may be derived from any suitable source of generated and / or stored electrical energy. For example, the power supply voltage V S may be supplied from one or more wind turbines and / or one or more energy storage systems comprising a capacitor and / or a battery. The grid voltage V g can have a predetermined magnitude and frequency based on the desired characteristics of the power grid where the MMC1 is installed. Accordingly, the MMC1 can operate to provide a voltage source in accordance with these desired characteristics of the grid voltage V g . The illustrated MMC1 outputs the grid voltage V g as a (n approximate) sine wave having a frequency and an amplitude.

[0047] The MMC1 includes a plurality of arms 2a, 2b, 2c, which may be collectively or generally referred to as "arm 2". Each arm 2 corresponds to a different phase V S of the output grid voltage V a , V b , V c . As a result, the three arms 2 provide a three-phase grid voltage V g , and each phase is separated by a substantially 120-degree phase.

[0048] Each arm 2 of the MMC1 includes a plurality of converter cells 3, which may also be referred to as "sub-modules 3". Each converter cell 3 includes a half-bridge or full-bridge switching circuit arranged around a capacitor. An example of a full-bridge converter cell 3 is shown in FIG. 2, where a plurality of semiconductor switches 4 are arranged in a full-bridge configuration around a capacitor 5.

[0049] Therefore, each converter cell 3 can be switched on and off according to a switching pattern via the coordinated control of the semiconductor switches 4 of each converter cell 3, and as a result, the arm 2 on which the converter cell 3 is located contributes to the phase of the entire grid voltage V S In response to the contribution to the process, capacitor 5 can be discharged in either the positive or negative direction.

[0050] Each converter cell 3, or at least several converter cells 3, can be configured with similar capacitors 5 such that each converter cell 3 has an equal contribution to its voltage. That is, the total output grid voltage V g Entering, or the full output grid voltage V g When switching to exit from (and thereby forming a substantially sinusoidal output), it can be said that the discharge of capacitor 5 from each converter cell 3 contributes the same (or at least substantially the same) voltage. This voltage difference 3 to which each converter cell contributes can be referred to as ΔV.

[0051] To more closely approximate a sinusoidal signal, more converter cells 3 can be used per arm 2, with each converter cell 3 contributing a relatively low ΔV. If each arm 2 contains N converter cells 3 to output each phase of the grid voltage Vg, then ΔV is V g It can be constructed as the value obtained by dividing by N.

[0052] Each arm 2 of the MMC1 may be composed of one or more converter valve assemblies.

[0053] Although this specification describes MMC, it will be understood that this disclosure may relate to substantially any type of converter having multiple converter cells.

[0054] Figure 3 schematically shows a perspective view of the prismatic converter cell 3. The prismatic converter cell has a length L, a width W, and a height H, and these labels can be arbitrarily assigned and are therefore interchangeable.

[0055] In some alternative embodiments of the present disclosure, the converter cell 3 may have different shapes, including, for example, triangular faces or circular faces (i.e., cylindrical). That is, the converter cell 3 may have a three-dimensional (3D) form factor with the shortest dimensions of height, width, and length, the shortest dimension may be equal to the longest or second longest dimension.

[0056] The illustrated converter cell 3 is a rectangular parallelepiped with a height H that is smaller than its width W, and its width W is smaller than its length L. Therefore, it can be seen that the shortest dimension of the illustrated prismatic converter cell 3 is its height H.

[0057] Figures 4a and 4b show a conventional converter valve assembly arrangement configuration 10 in which multiple conversion cells 3 are arranged in layers. According to such a conventional arrangement configuration, multiple such layers can be stacked on top of each other to form part of a converter arm. Thus, multiple such stacks can constitute an arm of a converter.

[0058] The 24 converter cells 3 within a layer are arranged in two columns, as indicated by the solid arrows, and connected in series. As a result, the first and last connected cells 3 are adjacent to each other and have a voltage difference of 24ΔV relative to each other. Therefore, the spacing between the two columns must be determined based on this voltage difference to reduce the risk of electric arc discharge or other interference effects between the first and last series-connected cells 3. Similar considerations may apply to the spacing between layers within a stack, and / or between stacks.

[0059] However, it will be understood that such spacing can be a waste of space, since not all cells 3 in a layer have this same voltage difference to their spatially nearest neighbors. In fact, at the opposite end of the column (i.e., the furthest as shown in Figure 4a), the opposing cells 3 on both sides of the column are directly connected to each other and therefore do not require spacing between cells configured to prevent electric arc discharge between cells 3 with a voltage difference of 24ΔV.

[0060] Furthermore, such vertical stacking may impose structural limitations on the number of cells 3 that can be included in a converter valve assembly. In other words, “vertical stacking” can be thought of as arranging prismatic cells whose longest dimensions are perpendicular to the plane in which they are arranged. Thus, multiple such vertically arranged converter valve assemblies (sometimes called “sub-arms”) may be required to form the arms of the converter. During seismic events (e.g., earthquakes), these sub-arms may displace relative to each other, potentially impairing the operation of the converter.

[0061] Accordingly, according to one aspect of the present disclosure, a converter valve assembly is provided that overcomes at least some of these problems in the prior art converter valve assemblies shown in Figures 4a and 4b.

[0062] Figures 5a and 5b show one embodiment of a converter valve assembly 20 according to one aspect of the present disclosure.

[0063] According to the illustrated embodiment, the converter valve assembly 20 includes three equal groups 6a, 6b, and 6c of prismatic converter cells 3a to ad (sometimes commonly referred to as "converter cells 3"). That is, the 30 converter cells 3 shown are evenly distributed so that 10 converter cells 3 are arranged within each group 6a, 6b, and 6c. Group 6a includes converter cells 3a to j, group 6b includes converter cells 3l to 3t, and group 6c includes converter cells 3u to 3ad.

[0064] Each group 6a, 6b, and 6c of converter cell 9 is located within its respective plane 7a, 7b, and 7c. That is, for example, converter cells 3a to 3j are arranged such that plane 7a is defined by their relative arrangement, and plane 7a intersects all of converter cells 3a to 3j. Planes 7a, 7b, and 7c are spaced apart along axis 8, which is the horizontal axis 8 in this illustrated embodiment. The spacing along axis 8 is exaggerated in Figure 5a for clarity.

[0065] Within each group 6a, 6b, and 6c, the converter cells 3 are arranged according to a common arrangement configuration for all groups 6a, 6b, and 6c, and the converter cells 3 are connected in series. In group 6a, the converter cells 3 are connected in series from the first converter cell 3 of group 6a, i.e., converter cell 3a, to the last converter cell 3 of group 6a, i.e., converter cell 3j. In group 6b, the converter cells 3 are connected from converter cell 3k to 3t, and in group 6c, the converter cells 3 are connected from converter cell 3u to 3ad.

[0066] Groups 6a, 6b, and 6c are connected in series along axis 8 such that the last converter cell 3 of each group 6a, 6b, and 6c is connected to the first converter cell 3 of the preceding group 6a, 6b, and 6c. In Figure 5a, the last converter cell 3j of group 6a is connected to the first converter cell 3k of group 6b, and the last converter cell 3t of group 6b is connected to the first converter cell 3u of group 6c.

[0067] In the illustrated example, the arrangement of the converter cells 3 forms a spiral shape, as indicated by the superimposed arrows in Figure 5a. That is, as seen in Figure 5a, the converter cells 3 of groups 6a, 6b, and 6c are arranged around axis 8 and connected sequentially according to their radial positions around axis 8, thereby forming an open loop from the first converter cell 3 of groups 6a, 6b, and 6c to the last converter cell 3.

[0068] Since each of groups 6a, 6b, and 6c has the same arrangement configuration of converter cells 3 with respect to their spatial arrangement and electrical interconnections, it will be understood that the prismatic converter cells 3 of a group, for example group 6a, are arranged such that, during the operation of the converter valve assembly 20, a corresponding voltage difference exists between each converter cell 3 of group 6a and each corresponding converter cell 3 of the spatially closest adjacent group, for example group 6b.

[0069] In other words, each group 6a, 6b, and 6c contains a corresponding converter cell 3 in its corresponding location within the cell arrangement configuration. For example, converter cells 3a, 3k, and 3u are corresponding converter cells 3, and converter cells 3e, 3o, and 3y are corresponding converter cells 3, and so on. Thus, according to such an arrangement configuration, the voltage difference between converter cells 3a and 3k can correspond to (i.e., be the same as or substantially similar to) the voltage difference between converter cells 3e and 3o. The same applies to each pair of corresponding converter cells 3 within each adjacent group 6a, 6b, and 6c.

[0070] In particular, if each converter cell 3 contributes a voltage of ΔV, then it can be understood that there is a voltage difference of 10ΔV between converter cell 3a and 3k because there are 10 converter cells connected in series between converter cell 3a and 3k (i.e., converter cells 3a~j, all converter cells in group 6a). For the same reason, there is also a voltage difference of 10ΔV between converter cells 3b and 3l, 3c and 3m, 3d and 3n, etc.

[0071] Therefore, the spacing along axis 8 between groups 6a and 6b can be determined based on the distance required to prevent electric arc discharge due to a voltage difference of 10ΔV (it can be reduced, preferably minimized). Thus, since this is the voltage difference between all pairs of corresponding converter cells 3 in groups 6a and 6b, less space is wasted within the converter valve assembly 20, and therefore the overall volume of the converter valve assembly is reduced.

[0072] Figure 5a shows that each converter cell 3 in groups 6a, 6b, and 6c is aligned parallel to the axis 8, but it will be understood that in some examples, groups 6a, 6b, and 6c may be displaced by a certain amount perpendicular to the axis 8. Furthermore, although planes 7a, 7b, and 7c are shown to be perfectly parallel, it will be understood that some deviation from this can be tolerated while still achieving the favorable effects of a particular arrangement configuration of converter cells 3 within the converter valve device 20.

[0073] Figure 5a shows that each group 6a, 6b, and 6c of converter cell 3 is attached to its respective substructure 9a, 9b, and 9c. Figure 5b shows a top view of group 6a, illustrating the example shown, in which group 6a of converter cells 3a to 3j is rigidly attached to substructure 9a.

[0074] In particular, according to the illustrated embodiment, the substructure 9a comprises a plurality of rigid bars 11 and interconnecting parts 12, and the interconnecting parts 12 are configured to facilitate mechanical connection between interconnecting parts 12 of another substructure, for example, substructure 9b along axis 8 as shown in Figure 5a.

[0075] The specific structure of the substructure 9a can take any suitable form, but all converter cells 3a-j of group 6a are preferably rigidly attached to the same substructure 9a. Thus, the converter cells 3a-j can be held in place relative to each other so as to be able to maintain the spacing between them and thus maintain the proper operation of the group of converter cells 3a-j.

[0076] Converter cells 3a to 3j are connected in series from converter cell 3a to converter cell 3j using an electrical connection 13. Since converter cells 3a to 3j are connected in series according to their radial positions around axis 8 (i.e., in a counterclockwise order as shown in Figure 5b), it will be understood that the length of the electrical connection 13 may be advantageously shorter.

[0077] Figure 6 shows a converter valve assembly 30 including multiple groups 6a to 6g, each group 6a to 6g having the same number of converter cells 3, which are mounted on their respective substructures 9. The arrangement of cells 3 within a group may be the same as or similar to those described in relation to Figures 5a and 5b.

[0078] Groups 6a to 6g are arranged and configured within multiple parallel planes, spaced equally apart along the axis. In the illustrated example, the distance between the planes of each group is distance D. Distance D can be determined based on the voltage difference between each converter cell in a group (e.g., group 6a) and each corresponding converter cell in an adjacent group (e.g., group 6b).

[0079] It will be understood that, depending on the embodiment, the number of cells 3 per group 6a-6g can be increased or decreased. Furthermore, the number of groups 6a-6g can also be varied. In a preferred embodiment, if the converter arm is intended to have N converter cells 3, the number of cells per n groups may be N / n, leaving some remainder. Thus, the converter valve assembly 30 can constitute the entire arm of the converter.

[0080] Figure 7 shows a converter valve assembly 40 having shield structures 14a-14d and a stand assembly 15 for raising the support structure from the floor (e.g., the floor of the converter hole). The support structure may be formed by a rigid connection of multiple substructures 9.

[0081] The shielding structures 14a to 14d comprise a plurality of shielding elements 14a, 14b, 14c, and 14d arranged around each group within a plane defined by each group. Thus, the groups of converter cells 3 can be shielded from external interference, and the external environment can also be shielded from the electromagnetic effects of the converter valve assembly 40. For example, the shielding structures 14a to 14d can reduce the risk of electric arc discharge between the converter valve assembly 40 and its surrounding environment. The shielding structures 14a to 14d may be made from any suitable material, but preferably from a conductive metal.

[0082] The stand assembly 15 comprises a plurality of posts 16 formed from and / or coated with an insulating material. Figures 8a and 8b show alternative exemplary configurations of the stand assembly, with the configuration shown in Figure 8a corresponding to the configuration shown in Figure 7.

[0083] In the illustrated examples of Figures 7 and 8a, each group 6 of the converter cell 3 is attached to its respective substructure 9, and each substructure 9 is held by two insulating posts 16. Thus, the spacing between the groups 6 can be established by the relative arrangement configuration of the posts 16.

[0084] In the example illustrated in Figure 8b, multiple substructures 9, each having a group of converter cells 3 mounted on it, can be collectively mounted on a common mounting structure 17 via an intermediate set of posts 16b, for example, two posts 16a per substructure. The common mounting structure 17 can then be erected on the posts 16a.

[0085] With such an arrangement configuration, isolation between groups may be provided by insulating posts in the same manner as in the examples shown in Figures 7 and 8a. However, the risk of relative motion of the substructure caused by, for example, an earthquake-related event displacing different pairs of posts 16a by different amounts is reduced. Thus, the relative positions of the groups of converter cells 3 are advantageously preserved by such an arrangement configuration.

[0086] Figure 9 shows a perspective view of a portion of the support structure 18 for the converter valve assembly according to an exemplary embodiment of the present disclosure.

[0087] The support structure 18 comprises a plurality of substructures 9a to e similar to those described above, supported by a plurality of posts 16 similar to post 16 (or 16a), as described above in relation to Figures 7, 8a, and 8b.

[0088] The support structure 18 is further configured such that each substructure is rigidly connected to one or more rigid insulating connectors 19. Thus, a rigid, continuous structure can be formed, and the number of vertical supports 16 required to raise the support structure 18 from the floor can be reduced.

[0089] Therefore, for example, in the case of earthquake-related events, the same favorable elasticity as described in relation to Figure 8b can be achieved. Furthermore, the structure of the support structure 18 can be advantageously simplified.

[0090] Figure 10 shows a perspective view of the converter arm 70, which is formed as a single converter valve assembly 60 supported on the stand assembly 15. It will be seen that the amount of shield structure 14 is significantly less than the amount required for multiple vertically arranged sub-arms, such as in the arrangement configuration described in relation to Figures 4a and 4b.

[0091] The stand assembly 15 is shown having two posts 16 for each substructure 9, and each substructure 9 has a group of converter cells 3 mounted thereon, but it will be understood that other configurations, such as those described in relation to Figure 8b or Figure 9, can be adopted.

[0092] Figure 11 shows a method 1100 for manufacturing the above-described converter valve assembly according to one aspect of the present disclosure.

[0093] As shown in the figure, method 1100 may include arranging and configuring two or more equal groups of prismatic converter cells to form a converter valve assembly such that each group is arranged and configured in each of a plurality of parallel planes spaced apart along an axis (step 1110).

[0094] In such an arrangement configuration, the converter cells within a group are connected in series and arranged such that their shortest dimensions are perpendicular to the plane, each group is connected in series along an axis, and the arrangement of the prismatic converter cells within a group is configured such that, during the operation of the converter valve assembly, a corresponding voltage difference exists between each converter cell within a group and each corresponding converter cell in the adjacent group that is spatially closest to the aforementioned converter cell. Such a method may be carried out manually or using some robotic manipulator means, depending on the embodiment.

[0095] While this disclosure is open to various modifications and alternative forms, specific embodiments are shown and described as examples in relation to the drawings in order to clearly illustrate the various advantageous aspects of this disclosure. However, the detailed description and accompanying drawings herein are not intended to limit this disclosure to any particular form disclosed. Rather, the intention is to encompass all modifications, equivalents, and alternatives that fall within the scope of the accompanying claims.

Claims

1. A converter valve assembly (20) for a power grid system, The system comprises two or more equal groups (6a, 6b, 6c) of prismatic converter cells (3a to ad), each group (6a, 6b, 6c) being arranged within each of the planes (7a, 7b, 7c) of a plurality of parallel planes spaced apart along a certain axis (8). The converter cells (3a to j) within group (6a) are connected in series and are arranged such that their shortest dimension is perpendicular to the plane (7a). The aforementioned groups (6a, 6b, 6c) are connected in series along the shaft (8), The prismatic converter cells (3a-j) in group (6a) are arranged around the axis (8) such that, during operation of the converter valve assembly (20), a corresponding voltage difference exists between each converter cell (3a-j) in group (6a) and each corresponding converter cell (3k-t) in the adjacent group (6b) that is spatially closest to each converter cell (3a-j), and are connected in order according to their radial positions around the axis (8).

2. The converter valve assembly according to claim 1, wherein each group is connected in series from the first converter cell to the last converter cell of the group according to a cell arrangement configuration common to all groups, and the last converter cell of the group is connected to the first converter cell of an adjacent group.

3. The converter valve assembly according to claim 1 or 2, wherein each converter cell in a group is position-aligned with a corresponding converter cell in an adjacent group, and the corresponding converter cells have the same position in the cell arrangement configuration.

4. The converter valve assembly according to claim 1 or 2, wherein the plurality of parallel planes are spaced apart along the axis by an amount corresponding to the voltage difference between each converter cell in the group and each corresponding converter cell in the adjacent group.

5. The converter valve assembly according to claim 1 or 2, wherein each group is rigidly mounted on its respective substructure.

6. The converter valve assembly according to claim 5, wherein each substructure is rigidly connected along the axis, thereby forming a support structure for the converter valve assembly.

7. The converter valve assembly according to claim 6, wherein the lower structure is rigidly connected by an insulating member.

8. Further comprising a mounting assembly for the support structure, The converter valve assembly according to claim 6, wherein the mounting assembly comprises a suspension assembly for suspending the support structure from the ceiling, or a stand assembly for raising the support structure from the floor.

9. The converter valve assembly according to claim 8, wherein the stand assembly comprises a plurality of posts configured to provide electrical insulation from the floor.

10. Each substructure is attached to its respective one-terrier post, or The converter valve assembly according to claim 8, wherein multiple substructures are mounted via a common mounting structure.

11. The converter valve assembly according to claim 1 or 2, further comprising a group-by-group shield structure arranged within the aforementioned plane.

12. The converter valve assembly according to claim 1 or 2, wherein the converter valve assembly constitutes an arm of the converter.

13. The converter valve assembly according to claim 1 or 2, wherein the converter having the converter valve assembly is a modular multilevel converter configured to supply power to a power grid.

14. A method (1100) for manufacturing a converter valve assembly according to claim 1 or 2, Two or more equal groups of prismatic converter cells, The process (1110) includes arranging each group so that it is positioned within each of a plurality of parallel planes spaced apart along a certain axis, The converter cells within the group are connected in series and arranged such that their shortest dimension is perpendicular to the plane. Each group is connected in series along the aforementioned axis, Method (1100), wherein the arrangement configuration of the prismatic converter cells within a group is configured such that, during the operation of the converter valve assembly, a corresponding voltage difference exists between each converter cell within the group and each corresponding converter cell in the adjacent group that is spatially closest to each converter cell.

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