A soft start process high valve group full bridge sub-module voltage equalization control method and system

Abstract

The application discloses a soft start process high valve group full bridge sub-module voltage equalization control method and system, the method comprises the following steps: calculating the average voltage of the upper and lower bridge arm full bridge sub-module capacitor; determining the number of removed sub-modules according to the size relationship of the average voltage of the upper and lower bridge arm full bridge sub-module capacitor; removing, reordering and distributing the upper and lower bridge arm full bridge sub-modules. The system comprises a voltage calculation module, a removal calculation module and a distribution module. The soft start process high valve group full bridge sub-module voltage equalization control method and system re-distribute the number of removed sub-modules of the upper and lower bridge arms according to the size relationship of the average voltage of the upper and lower bridge arm full bridge sub-module capacitor, adjust the charging rate of the upper and lower bridge arm full bridge sub-module capacitor, and realize the balanced control of the high valve group full bridge sub-module capacitor.

Description

Technical Field

[0001] This invention relates to the field of power transmission regulation technology, and in particular to a method and system for equalizing voltage control of a full-bridge submodule of a high-valve group during soft-start process. Background Technology

[0002] In flexible DC transmission systems with high and low valve group wiring (where the valve group is a hybrid cascade of full-bridge and half-bridge submodules), when the low valve group starts up and the AC circuit breaker of the high valve group is not closed, an imbalance in the full-bridge submodule capacitor voltages of different valve towers in each phase of the high valve group will occur due to the parasitic capacitance to ground of the transmission line and the parasitic capacitance to ground of the converter valve top. During the soft start-up process of operational flexible DC projects, a sorting-based submodule capacitor voltage balancing control method is typically used. This method adjusts in real time to always engage the submodule with the lower capacitor voltage (during soft start-up, the submodule is in a charging state), thereby achieving balanced submodule capacitor voltage control. Existing sorting-based submodule capacitor voltage balancing control methods, operating on a bridge arm basis, can achieve balanced control of the full-bridge submodule capacitor voltages between different valve towers within a bridge arm, but they cannot solve the voltage imbalance problem between the full-bridge submodule capacitors of the upper and lower bridge arms. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide a voltage equalization control and system for the full-bridge submodule of the high valve group during soft start-up, which can realize the equalization control of the capacitor of the full-bridge submodule of the high valve group.

[0004] In a first aspect, embodiments of the present invention provide a method for pressure equalization control of a high-valve group full-bridge submodule during soft-start, comprising:

[0005] Calculate the average voltage of the capacitors in the upper and lower bridge arm full-bridge submodules.

[0006] The number of submodules to be removed is determined based on the relationship between the average voltage of the capacitors in the upper and lower bridge arms of the full-bridge submodules.

[0007] The full-bridge submodules of the upper and lower bridge arms are cut off, reordered, and reassigned.

[0008] In conjunction with the first aspect, the present invention provides a first possible implementation of the first aspect, wherein calculating the average voltage of the capacitors of the upper and lower bridge arms full-bridge submodules includes:

[0009] When the low valve group starts, the AC circuit breaker of the high valve group is not closed, and the full bridge submodule of the high valve group is charged.

[0010] Calculate the average voltage of the capacitor in the upper arm full-bridge submodule.

[0011] Calculate the average voltage of the capacitor in the lower arm full-bridge submodule.

[0012] Where n is the number of full-bridge sub-modules in each bridge arm, u FBSMui Let u be the voltage of the capacitor in the i-th full-bridge submodule of the upper bridge arm. FBSMdi Let be the voltage of the capacitor in the i-th full-bridge submodule of the lower bridge arm.

[0013] In conjunction with the first aspect, this invention provides a second possible implementation of the first aspect, wherein determining the number of submodules to be removed based on the average voltage relationship between the capacitors of the upper and lower bridge arms of the full-bridge submodules includes:

[0014] Determine the number of sub-modules to be cut from the upper bridge arm.

[0015] Determine the number of submodules to be cut from the lower bridge arm.

[0016] Where, n u n is the number of submodules cut off in the upper bridge arm. d n0 represents the number of sub-modules cut off from the lower bridge arm, n0 represents the number of sub-modules cut off from the low valve group during the active pressure equalization process, and Δ represents the preset reference value.

[0017] In conjunction with the first aspect, this invention provides a third possible implementation of the first aspect, wherein the cutting, reordering, and allocation of the upper and lower bridge arm full-bridge submodules includes:

[0018] By combining the sorting strategy within the bridge arm, a certain number of sub-modules with higher voltage are cut off.

[0019] The remaining upper and lower bridge arm full-bridge sub-modules after removal are reordered.

[0020] The remaining upper and lower bridge arm full-bridge submodules after the cut-off are controlled under negative pressure, and the half-bridge submodules are controlled in a locked state.

[0021] Secondly, embodiments of the present invention also provide a pressure equalization control system for a high-valve group full-bridge submodule during soft-start process, comprising:

[0022] The voltage calculation module is used to calculate the average voltage of the capacitors in the upper and lower bridge arm full-bridge submodules.

[0023] The cut-off calculation module is used to determine the number of sub-modules to be cut off based on the relationship between the average voltage of the capacitors of the upper and lower bridge arms of the full-bridge sub-modules.

[0024] The allocation module is used to cut, reorder, and allocate the full-bridge sub-modules of the upper and lower bridge arms.

[0025] In conjunction with the second aspect, embodiments of the present invention provide a first possible implementation of the second aspect, wherein the voltage calculation module includes:

[0026] The soft start unit is used to start the low valve group. When the AC circuit breaker of the high valve group is not closed, the full bridge submodule of the high valve group is charged.

[0027] The upper bridge arm voltage calculation unit is used to calculate the average voltage of the capacitors in the upper bridge arm full-bridge submodule.

[0028] The lower bridge arm voltage calculation unit is used to calculate the average voltage of the capacitors in the lower bridge arm full-bridge submodule.

[0029] Where n is the number of full-bridge submodules in each arm, uFBSMui is the voltage of the capacitor of the i-th full-bridge submodule in the upper arm, and uFBSMdi is the voltage of the capacitor of the i-th full-bridge submodule in the lower arm.

[0030] In conjunction with the second aspect, this embodiment of the invention provides a second possible implementation of the second aspect, wherein the resection calculation module includes:

[0031] The upper arm cutoff calculation unit is used to determine the number of sub-modules for upper arm cutoff.

[0032] The lower bridge arm resection calculation unit is used to determine the number of sub-modules for lower bridge arm resection.

[0033]

[0034] Where, n u n is the number of submodules cut off in the upper bridge arm. d n0 represents the number of sub-modules cut off from the lower bridge arm, n0 represents the number of sub-modules cut off from the low valve group during the active pressure equalization process, and Δ represents the preset reference value.

[0035] In conjunction with the second aspect, embodiments of the present invention provide a third possible implementation of the second aspect, wherein the allocation module includes:

[0036] The cut-off unit is used to cut off a certain number of high-voltage submodules by combining the sorting strategy inside the bridge arm.

[0037] The sorting unit is used to reorder the remaining upper and lower bridge arm full-bridge sub-modules after removal.

[0038] The control unit is used to control the remaining upper and lower bridge arm full bridge submodules to negative pressure and the half bridge submodules to a locked state after the cut-off.

[0039] Thirdly, embodiments of the present invention also provide a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the pressure equalization control method for the high-valve group full-bridge submodule during soft start as described above.

[0040] Fourthly, embodiments of the present invention also provide a computer-readable storage medium having a computer program stored thereon, characterized in that, when the computer program is executed by a processor, it implements the pressure equalization control method for the high-valve group full-bridge submodule during soft-start process as described above.

[0041] The beneficial effects of the embodiments of the present invention are:

[0042] The present invention relates to a method and system for equalizing the voltage of the full-bridge submodules of the high-valve group during the soft-start process. Based on the relationship between the average voltage of the capacitors of the upper and lower bridge arms, the number of submodules to be cut off in the upper and lower bridge arms is redistributed, and the charging rate of the capacitors of the full-bridge submodules in the upper and lower bridge arms is adjusted, thereby achieving balanced control of the capacitors of the full-bridge submodules of the high-valve group. Attached Figure Description

[0043] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a flowchart of the pressure equalization control method for the full-bridge submodule of the high-valve group during the soft-start process of the present invention;

[0045] Figure 2 This is a schematic diagram of a flexible DC transmission system based on the high and low valve group wiring configuration.

[0046] Figure 3 This is a schematic diagram of the circuit structure of a flexible DC transmission system based on a high-low valve group connection when the AC circuit breaker of the high valve group is not closed.

[0047] Figure 4 This is a complete flowchart illustrating the pressure equalization control method of the high-valve group full-bridge submodule during the soft-start process of the present invention. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0049] Please refer to Figures 1 to 4 The first embodiment of the present invention provides a method for pressure equalization control of a full-bridge submodule of a high-valve group during a soft-start process, comprising:

[0050] Calculate the average voltage of the capacitors in the upper and lower bridge arm full-bridge submodules.

[0051] The number of submodules to be removed is determined based on the relationship between the average voltage of the capacitors in the upper and lower bridge arms of the full-bridge submodules.

[0052] The full-bridge submodules of the upper and lower bridge arms are cut off, reordered, and reassigned.

[0053] The calculation of the average voltage of the capacitors of the upper and lower bridge arm full-bridge submodules includes:

[0054] When the low valve group starts, the AC circuit breaker of the high valve group is not closed, and the full bridge submodule of the high valve group is charged.

[0055] Calculate the average voltage of the capacitor in the upper arm full-bridge submodule.

[0056] Calculate the average voltage of the capacitor in the lower arm full-bridge submodule.

[0057] Where n is the number of full-bridge sub-modules in each bridge arm, u FBSMui Let u be the voltage of the capacitor in the i-th full-bridge submodule of the upper bridge arm. FBSMdi Let be the voltage of the capacitor in the i-th full-bridge submodule of the lower bridge arm.

[0058] The step of determining the number of submodules to be removed based on the average voltage relationship between the capacitors of the upper and lower bridge arms of the full-bridge submodules includes:

[0059] Determine the number of sub-modules to be cut from the upper bridge arm.

[0060] Determine the number of submodules to be cut from the lower bridge arm.

[0061] Where, n u n is the number of submodules cut off in the upper bridge arm. d n0 represents the number of sub-modules cut off from the lower bridge arm, n0 represents the number of sub-modules cut off from the low valve group during the active pressure equalization process, and Δ represents the preset reference value.

[0062] Please refer to Figures 2 to 3 A second embodiment of the present invention provides a pressure equalization control system for a high-valve group full-bridge submodule during soft-start process, comprising:

[0063] The voltage calculation module is used to calculate the average voltage of the capacitors in the upper and lower bridge arm full-bridge submodules.

[0064] The cut-off calculation module is used to determine the number of sub-modules to be cut off based on the relationship between the average voltage of the capacitors of the upper and lower bridge arms of the full-bridge sub-modules.

[0065] The allocation module is used to cut, reorder, and allocate the full-bridge sub-modules of the upper and lower bridge arms.

[0066] The voltage calculation module includes:

[0067] The soft start unit is used to start the low valve group. When the AC circuit breaker of the high valve group is not closed, the full bridge submodule of the high valve group is charged.

[0068] The upper bridge arm voltage calculation unit is used to calculate the average voltage of the capacitors in the upper bridge arm full-bridge submodule.

[0069] The lower bridge arm voltage calculation unit is used to calculate the average voltage of the capacitors in the lower bridge arm full-bridge submodule.

[0070] Where n is the number of full-bridge submodules in each arm, uFBSMui is the voltage of the capacitor of the i-th full-bridge submodule in the upper arm, and uFBSMdi is the voltage of the capacitor of the i-th full-bridge submodule in the lower arm.

[0071] The resection calculation module includes:

[0072] The upper arm cutoff calculation unit is used to determine the number of sub-modules for upper arm cutoff.

[0073] The lower bridge arm resection calculation unit is used to determine the number of sub-modules for lower bridge arm resection.

[0074]

[0075] Where, n u n is the number of submodules cut off in the upper bridge arm. d n0 represents the number of sub-modules cut off from the lower bridge arm, n0 represents the number of sub-modules cut off from the low valve group during the active pressure equalization process, and Δ represents the preset reference value.

[0076] The allocation module includes:

[0077] The cut-off unit is used to cut off a certain number of high-voltage submodules by combining the sorting strategy inside the bridge arm.

[0078] The sorting unit is used to reorder the remaining upper and lower bridge arm full-bridge sub-modules after removal.

[0079] The control unit is used to control the remaining upper and lower bridge arm full bridge submodules to negative pressure and the half bridge submodules to a locked state after the cut-off.

[0080] A third embodiment of the present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the pressure equalization control method for the high-valve group full-bridge submodule during soft start as described above.

[0081] A fourth embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, characterized in that, when the computer program is executed by a processor, it implements the pressure equalization control method for the high-valve group full-bridge submodule during soft start as described above.

[0082] The embodiments of the present invention aim to protect a pressure equalization control method and system for a high-valve group full-bridge submodule during soft-start, which has the following effects:

[0083] The present invention relates to a method and system for equalizing the voltage of the full-bridge submodules of the high-valve group during the soft-start process. Based on the relationship between the average voltage of the capacitors of the upper and lower bridge arms, the number of submodules to be cut off in the upper and lower bridge arms is redistributed, and the charging rate of the capacitors of the full-bridge submodules in the upper and lower bridge arms is adjusted, thereby achieving balanced control of the capacitors of the full-bridge submodules of the high-valve group.

[0084] The computer program product of the soft-start process high valve group full bridge submodule pressure equalization control method and device provided in the embodiments of the present invention includes a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the methods in the preceding method embodiments. For specific implementation, please refer to the method embodiments, which will not be repeated here.

[0085] Specifically, the storage medium can be a general-purpose storage medium, such as a removable disk or hard disk. When the computer program on the storage medium is run, it can execute the above-mentioned soft-start process high valve group full bridge submodule voltage equalization control method, thereby realizing the equalization control of the capacitors of the high valve group full bridge submodule.

[0086] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a processor-executable, non-volatile, computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0087] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for pressure equalization control of a full-bridge submodule of a high-voltage valve group during soft-start process, characterized in that, include: Calculate the average voltage of the capacitors in the upper and lower bridge arm full-bridge submodules; The number of submodules to be removed is determined based on the relationship between the average voltage of the capacitors in the upper and lower bridge arms of the full-bridge submodules. The full-bridge sub-modules of the upper and lower bridge arms are cut off, reordered, and reassigned. The process of cutting, reordering, and allocating the full-bridge submodules of the upper and lower bridge arms includes: Based on the sorting strategy within the bridge arm, a certain number of sub-modules are cut off; The remaining upper and lower bridge arm full-bridge sub-modules after removal are reordered; The remaining upper and lower bridge arm full bridge submodules after the cut are controlled to negative pressure, and the half bridge module is controlled to the locked state. The calculation of the average voltage of the capacitors of the upper and lower bridge arm full-bridge submodules includes: When the low valve group starts, the AC circuit breaker of the high valve group is not closed, and the full bridge submodule of the high valve group is charged. Calculate the average voltage of the capacitor in the upper arm full-bridge submodule. ; Calculate the average voltage of the capacitor in the lower arm full-bridge submodule. ; Where n is the number of full-bridge sub-modules in each bridge arm, u FBSMui Let be the voltage of the capacitor in the i-th full-bridge submodule of the upper bridge arm. u FBSMdi The voltage of the capacitor in the i-th full-bridge submodule of the lower bridge arm; The determination of the number of submodules to be removed based on the average voltage relationship between the capacitors of the upper and lower bridge arms of the full-bridge submodules includes: Determine the number of submodules to be cut from the upper bridge arm. ; Determine the number of submodules to be cut from the lower bridge arm. ; in, n u This represents the number of sub-modules removed from the upper bridge arm. n d The number of submodules cut off in the lower bridge arm. n 0 represents the number of sub-modules disconnected by the low-voltage valve group during the active pressure equalization process. This is a preset reference value.

2. A pressure equalization control system for a high-voltage valve group full-bridge submodule during soft-start process, characterized in that, include: The voltage calculation module is used to calculate the average voltage of the capacitors in the upper and lower bridge arm full-bridge submodules. The cut-off calculation module is used to determine the number of sub-modules to be cut off based on the relationship between the average voltage of the capacitors of the upper and lower bridge arms full-bridge sub-modules. The allocation module is used to cut, reorder, and allocate the full-bridge sub-modules of the upper and lower bridge arms; The allocation module includes: The cut-off unit is used to cut off a certain number of sub-modules by combining the sorting strategy inside the bridge arm; The sorting unit is used to reorder the remaining upper and lower bridge arm full-bridge sub-modules after the removal. The control unit is used to control the remaining upper and lower bridge arm full bridge submodules to negative pressure and the half bridge module to lockout state after the cut-off. The voltage calculation module includes: The soft starter unit is used to start the low valve group. When the AC circuit breaker of the high valve group is not closed, the full bridge submodule of the high valve group is charged. The upper arm voltage calculation unit is used to calculate the average voltage of the capacitors in the upper arm full-bridge submodule. ; The lower bridge arm voltage calculation unit is used to calculate the average voltage of the capacitors in the lower bridge arm full-bridge submodule. ; Where n is the number of full-bridge sub-modules in each bridge arm, u FBSMui Let be the voltage of the capacitor in the i-th full-bridge submodule of the upper bridge arm. u FBSMdi The voltage of the capacitor in the i-th full-bridge submodule of the lower bridge arm; The resection calculation module includes: The upper arm cutoff calculation unit is used to determine the number of sub-modules for upper arm cutoff. ; The lower bridge arm resection calculation unit is used to determine the number of sub-modules for lower bridge arm resection. ; in, n u This represents the number of sub-modules removed from the upper bridge arm. n d The number of submodules cut off in the lower bridge arm. n 0 represents the number of sub-modules disconnected by the low-voltage valve group during the active pressure equalization process. This is a preset reference value.

3. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the pressure equalization control method for the high-valve group full-bridge submodule as described in claim 1.

4. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the pressure equalization control method for the high-valve group full-bridge submodule as described in claim 1.

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