Power transmission control method, system and equipment of series-parallel converter valve topology and medium

Abstract

The invention relates to the technical field of power transmission systems, and provides a power transmission control method, a power transmission control system, power transmission control equipment and a medium for a series-parallel converter valve topology. According to the total number of single-bridge-arm sub-modules and the use proportion of IGCT sub-modules in the series-parallel converter valve topology, the number of real-time input sub-modules of an upper bridge arm and the number of real-time input sub-modules of a lower bridge arm in the series-parallel converter valve topology are calculated on the basis of the nearest level approximation modulation principle, wherein the total number of single-bridge-arm sub-modules and the use proportion of IGCT sub-modules are adopted in main wiring of the series-parallel converter valve topology; and executing power transmission control according to the number of the upper bridge arm real-time input sub-modules and the number of the lower bridge arm real-time input sub-modules. According to the invention, the advantage complementation of the insulated gate bipolar transistor and the integrated gate commutated thyristor can be realized based on the flexible matching of the IGBT sub-module and the IGCT sub-module, the DC power transmission performance of a power transmission system can be ensured, and the construction cost of a flexible DC converter station can be greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of power transmission systems, and in particular to a power transmission control method, system, equipment and medium of a hybrid converter valve topology. Background Art

[0002] Flexible DC transmission technology is one of the important technologies to adapt to the development of new power systems. With the increase in demand for large-scale development of new energy, the core role of flexible DC transmission in DC transmission technology will become increasingly prominent.

[0003] The main component of the current flexible DC transmission technology is the insulated gate bipolar transistor (IGBT) converter valve, which is a high-efficiency power semiconductor component, but it is also subject to the construction, cost and production capacity of DC transmission projects due to its weak reverse withstand voltage, large operating loss, small transmission capacity, easy latch-up phenomenon and high cost. Although the integrated gate-commutated thyristor (IGCT) converter valve is an improved new topology with high withstand voltage capability, high power capacity, low conduction loss, small size and high reliability, it still has application defects such as switching frequency limitation, special drive circuit requirements, poor waveform quality and high maintenance cost, and cannot directly replace the use of IGBT converter valves in transmission systems. Therefore, it is of great significance to achieve complementary advantages based on the respective advantages of IGBT converter valves and IGCT converter valves to help the low-cost construction of large-capacity flexible DC transmission projects and improve transmission performance. Summary of the invention

[0004] The purpose of the present invention is to provide a power transmission control method for a hybrid converter valve topology, which constructs a hybrid converter valve topology by connecting an IGBT submodule and an IGCT submodule in series, and reliably and stably controls the power transmission of the hybrid converter valve topology based on the configuration ratio of the IGBT submodule and the IGCT submodule in the hybrid converter valve topology and the nearest level approximation modulation principle. The method can complement the advantages of insulated gate bipolar transistors and integrated gate-commutated thyristors based on the flexible ratio of the IGBT submodule and the IGCT submodule, which can not only ensure the DC transmission performance of the transmission system, but also greatly reduce the construction cost of the flexible DC converter station, thereby effectively improving the economy of the flexible DC transmission technology in large-scale new energy DC transmission scenarios.

[0005] In order to achieve the above-mentioned purpose, a power transmission control method, system, equipment and medium of a hybrid converter valve topology are provided.

[0006] In a first aspect, an embodiment of the present invention provides a power transmission control method of a hybrid converter valve topology, wherein the hybrid converter valve topology includes a plurality of IGBT submodules and IGCT submodules connected in series; the main connection of the hybrid converter valve topology adopts a pseudo-bipolar structure; the method includes the following steps: According to the total number of single-bridge-arm submodules and the usage ratio of IGCT submodules in the hybrid converter valve topology, the number of upper-bridge-arm real-time put-into-use submodules and the number of lower-bridge-arm real-time put-into-use submodules in the hybrid converter valve topology are calculated based on the nearest level approximation modulation principle; Power transmission control is performed according to the number of submodules put into operation in real time in the upper bridge arm and the number of submodules put into operation in real time in the lower bridge arm.

[0007] Furthermore, the total number of single-arm submodules in the hybrid converter valve topology is calculated based on the target flexible DC output voltage, the voltage of a single submodule and Kirchhoff's voltage law.

[0008] Furthermore, the number of IGBT single-bridge-arm submodules and the number of IGCT single-bridge-arm submodules in the hybrid converter valve topology are determined by the following steps: When the usage ratio of the IGCT submodule is less than the preset replacement ratio, the number of the IGCT single bridge arm submodules is obtained based on the product of the total number of the single bridge arm submodules and the usage ratio of the IGCT submodules, and the number of the IGBT single bridge arm submodules is obtained according to the difference between the total number of the single bridge arm submodules and the number of the IGCT single bridge arm submodules; When the usage ratio of the IGCT sub-module is greater than or equal to the preset replacement ratio, the number of the IGBT single bridge arm sub-modules and the number of the IGCT single bridge arm sub-modules are calculated based on the single valve group inter-pole voltage constraint according to the total number of the single bridge arm sub-modules, the rated operating voltage of the IGBT sub-modules and the rated operating voltage of the IGCT sub-modules.

[0009] Furthermore, the single valve group inter-electrode voltage constraint is expressed as: In the formula, and Respectively represent the number of IGBT single bridge arm submodules and the number of IGCT single bridge arm submodules; and Respectively represent the rated operating voltages of the IGBT submodule and the IGCT submodule; Indicates the inter-electrode voltage of a single valve group.

[0010] Further, the step of calculating the number of upper bridge arm real-time input submodules and the number of lower bridge arm real-time input submodules in the hybrid converter valve topology based on the nearest level approximation modulation principle according to the total number of single bridge arm submodules and the usage ratio of IGCT submodules in the hybrid converter valve topology includes: When the usage ratio of the IGCT submodule is less than the preset replacement ratio, the number of the lower bridge arm real-time put-in-place submodules and the number of the upper bridge arm real-time put-in-place submodules are calculated based on the first expression according to the total number of the single bridge arm submodules, the inter-electrode voltage of the single valve group, the valve-side modulation wave voltage and the rated working voltage of the IGBT submodule; the first expression is expressed as: In the formula, and They respectively represent the number of sub-modules put into use in the lower bridge arm and the number of sub-modules put into use in the upper bridge arm at time t when the usage ratio of the IGCT sub-modules is less than the preset replacement ratio; Indicates the rated operating voltage of the IGBT submodule; Indicates the inter-electrode voltage of a single valve group; Indicates the valve side modulation wave voltage; Indicates the total number of single bridge arm submodules; When the usage ratio of the IGCT sub-module is greater than or equal to the preset replacement ratio, the number of lower bridge arm real-time put-in-place sub-modules and the number of upper bridge arm real-time put-in-place sub-modules are obtained according to the total number of single bridge arm sub-modules, the preset modulation sorting strategy and the current number of lower bridge arm put-in-place sub-modules.

[0011] Further, when the preset modulation sorting strategy is to sort the IGBT submodules first and then sort the IGCT submodules, the step of obtaining the number of lower bridge arm real-time put-in-place submodules and the number of upper bridge arm real-time put-in-place submodules according to the total number of single bridge arm submodules, the preset modulation sorting strategy and the current number of lower bridge arm put-in-place submodules includes: When the current number of lower bridge arm submodules is less than or equal to the number of IGBT single bridge arm submodules, the number of lower bridge arm real-time submodules and the number of upper bridge arm real-time submodules are calculated based on the first expression according to the total number of single bridge arm submodules, the single valve group inter-electrode voltage, the valve side modulation wave voltage and the rated working voltage of the IGBT submodule; When the current number of lower bridge arm submodules put into operation is greater than the number of IGBT single bridge arm submodules and the current number of lower bridge arm submodules put into operation is less than the total number of single bridge arm submodules, the number of lower bridge arm real-time submodules put into operation and the number of upper bridge arm real-time submodules put into operation are calculated based on the second expression according to the total number of single bridge arm submodules, the inter-electrode voltage of the single valve group, the valve-side modulation wave voltage, the rated operating voltage of the IGBT submodule, the number of IGBT single bridge arm submodules and the rated operating voltage of the IGCT submodule; the second expression is expressed as: In the formula, and They respectively indicate that the usage ratio of IGCT submodules is greater than or equal to the preset replacement ratio, and the IGBT submodules are sorted first. When the number of submodules put into use in the lower bridge arm is greater than the number of IGBT single bridge arm submodules, the number of submodules put into use in the lower bridge arm and the number of submodules put into use in the upper bridge arm at time t; Indicates the rated operating voltage of the IGCT submodule; Indicates the number of IGBT single bridge arm sub-modules.

[0012] Further, when the preset modulation sorting strategy is to sort the IGCT submodules first and then sort the IGBT submodules, the step of obtaining the number of lower bridge arm real-time put-in-place submodules and the number of upper bridge arm real-time put-in-place submodules according to the total number of single bridge arm submodules, the preset modulation sorting strategy and the current number of lower bridge arm put-in-place submodules includes: When the current number of lower bridge arm submodules is less than or equal to the number of IGCT single bridge arm submodules, the number of lower bridge arm real-time submodules and the number of upper bridge arm real-time submodules are calculated based on the third expression according to the total number of single bridge arm submodules, the single valve group inter-electrode voltage, the valve-side modulation wave voltage and the rated working voltage of the IGCT submodule; the third expression is expressed as: In the formula, and They respectively indicate that the usage ratio of IGCT submodules is greater than or equal to the preset replacement ratio. The IGCT submodules are sorted first. When the number of submodules put into use in the lower bridge arm is less than or equal to the number of submodules in the IGCT single bridge arm, the number of submodules put into use in the lower bridge arm and the number of submodules put into use in the upper bridge arm at time t are real-time; Respectively represent the rated operating voltage of the IGCT submodule; When the current number of lower bridge arm submodules put into operation is greater than the number of IGCT single bridge arm submodules and the current number of lower bridge arm submodules put into operation is less than the total number of single bridge arm submodules, the number of lower bridge arm real-time submodules put into operation and the number of upper bridge arm real-time submodules put into operation are calculated based on the fourth expression according to the total number of single bridge arm submodules, the single valve group inter-electrode voltage, the valve-side modulation wave voltage, the rated operating voltage of the IGBT submodule, the number of IGCT single bridge arm submodules and the rated operating voltage of the IGCT submodule; the fourth expression is expressed as: In the formula, and They respectively indicate that the usage ratio of IGCT submodules is greater than or equal to the preset replacement ratio. The IGCT submodules are sorted first. When the number of submodules put into use in the lower bridge arm is greater than the number of submodules in the IGCT single bridge arm, the number of submodules put into use in the lower bridge arm and the number of submodules put into use in the upper bridge arm at time t are real-time; Indicates the number of IGCT single bridge arm submodules.

[0013] In a second aspect, an embodiment of the present invention provides a power transmission control system of a hybrid converter valve topology, wherein the hybrid converter valve topology includes a plurality of IGBT submodules and IGCT submodules connected in series; the main connection of the hybrid converter valve topology adopts a pseudo-bipolar structure; the system includes: A submodule input analysis module is used to calculate the number of real-time input submodules of the upper bridge arm and the number of real-time input submodules of the lower bridge arm in the hybrid converter valve topology based on the nearest level approximation modulation principle according to the total number of single bridge arm submodules and the usage ratio of IGCT submodules in the hybrid converter valve topology; The power transmission control module is used to perform power transmission control according to the number of sub-modules put into operation in real time in the upper bridge arm and the number of sub-modules put into operation in real time in the lower bridge arm.

[0014] In a third aspect, an embodiment of the present invention further provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the computer program.

[0015] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the above method when executed by a processor.

[0016] The present invention provides a power transmission control method, system, device and medium of a hybrid converter valve topology, through which a plurality of IGBT submodules and IGCT submodules are used in series, and a hybrid converter valve topology is obtained by using a pseudo bipolar structure as the main wiring design, and the number of upper bridge arm real-time input submodules and the number of lower bridge arm real-time input submodules in the hybrid converter valve topology are calculated based on the nearest level approximation modulation principle according to the total number of single bridge arm submodules and the proportion of IGCT submodules used in the hybrid converter valve topology, and the technical scheme of power transmission control is executed according to the number of upper bridge arm real-time input submodules and the number of lower bridge arm real-time input submodules. Compared with the prior art, the power transmission control method of the hybrid converter valve topology can realize the complementary advantages of insulated gate bipolar transistors and integrated gate commutated thyristors based on the flexible ratio of IGBT submodules and IGCT submodules, which can not only ensure the DC transmission performance of the transmission system, but also greatly reduce the construction cost of the flexible DC converter station, thereby effectively improving the economy of the flexible DC transmission technology in the large-scale new energy DC transmission scenario. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of the structure of the hybrid converter valve topology in an embodiment of the present invention; Figure 2 is a schematic diagram of a flow chart of power transmission control of a hybrid converter valve topology in an embodiment of the present invention; Figure 3 1 is a schematic diagram of a steady-state waveform of a series-parallel converter valve topology in an embodiment of the present invention; Figure 4 1 is a waveform diagram of a hybrid converter valve topology under an AC three-phase grounding fault in an embodiment of the present invention; Figure 5 is a waveform diagram of a hybrid converter valve topology under a valve-side three-phase grounding fault in an embodiment of the present invention; Figure 6 1 is a waveform diagram of a hybrid converter valve topology under a DC positive pole grounding fault in an embodiment of the present invention; Figure 7 1 is a schematic diagram of the structure of a power transmission control system of a hybrid converter valve topology in an embodiment of the present invention; Figure 8 It is a diagram of the internal structure of a computer device in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and beneficial effects of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Obviously, the embodiments described below are part of the embodiments of the present invention and are only used to illustrate the present invention, but are not used to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] The power transmission control method of the hybrid converter valve topology provided by the present invention can be understood as an application defect of using IGBT converter valve based on DC power transmission technology, and a method is proposed to construct different numbers of IGBT sub-modules and IGCT sub-modules according to different ratios to obtain Figure 1 The hybrid converter valve topology shown (Upa is the upper bridge arm voltage of phase A, Usm is the voltage of a single submodule, Uva, Uvb, Uvc are the phase voltages of the three-phase AC side of A, B, C respectively, iva, ivb, ivc are the line currents of the three-phase AC side of A, B, C respectively, Udc is the pole-to-pole voltage of a single valve group, IGCT, IGBT are submodule types), and a technical solution for reliably controlling the power transmission of the hybrid converter valve topology based on the configuration ratio of the IGBT submodule and the IGCT submodule combined with the nearest level approximation modulation principle; the following embodiments will explain in detail the power transmission control method of the hybrid converter valve topology of the present invention.

[0020] In one embodiment, Figure 2 As shown, a power transmission control method of a hybrid converter valve topology is provided, wherein the hybrid converter valve topology includes a plurality of IGBT submodules and IGCT submodules connected in series; the main connection of the hybrid converter valve topology adopts a pseudo bipolar structure. The method includes the following steps: S11. According to the total number of single-arm submodules and the usage ratio of IGCT submodules in the hybrid converter valve topology, the number of upper-arm real-time submodules and the number of lower-arm real-time submodules in the hybrid converter valve topology are calculated based on the nearest level approximation modulation principle.

[0021] In practical applications, the total number of single-arm submodules and the proportion of IGCT submodules used in the hybrid converter valve topology can be determined based on the actual flexible DC transmission project requirements. The hybrid converter valve topology can be understood as a topology structure obtained by replacing some IGBT submodules in the topology that uses all IGBT submodules with IGCT submodules based on the proportion of IGCT submodules used. Specifically, the total number of single-arm submodules in the hybrid converter valve topology is calculated based on the target flexible DC output voltage, the voltage of a single submodule, and Kirchhoff's voltage law, that is, the total number of single-arm submodules is expressed as: In the formula, Indicates the target flexible DC output voltage; Indicates rounding to integer; Indicates the total number of single-arm submodules in the hybrid converter valve topology; It indicates the voltage of a single submodule, which can be calculated by referring to the rated operating voltage of IGBTs with existing market specifications (such as a 6-inch IGBT with a rated operating voltage of 4.5kV and a rated operating current of 2kA or 3kA).

[0022] Taking into account that in actual applications, when the proportion of IGCT sub-modules used increases to a certain extent, the corresponding increase in harmonics may lead to insufficient harmonic tolerance of the equipment, resulting in increased equipment operation risks. In order to ensure the stability of the hybrid converter valve topology, this embodiment preferably uses different methods to determine the number of IGBT single-bridge arm sub-modules and the number of IGCT single-bridge arm sub-modules in the hybrid converter valve topology based on different proportions of IGCT sub-modules used; specifically, the number of IGBT single-bridge arm sub-modules and the number of IGCT single-bridge arm sub-modules in the hybrid converter valve topology are determined by the following steps: When the usage ratio of the IGCT submodule is less than the preset replacement ratio, the number of the IGCT single bridge arm submodules is obtained based on the product of the total number of the single bridge arm submodules and the usage ratio of the IGCT submodules, and the number of the IGBT single bridge arm submodules is obtained according to the difference between the total number of the single bridge arm submodules and the number of the IGCT single bridge arm submodules; wherein the preset replacement ratio can be understood as the maximum replacement ratio that directly replaces part of the IGBT submodules in the converter valve topology that only uses IGBT submodules with IGCT submodules without causing an increase in harmonics, which can be determined based on the analysis of the actual application scenario. That is, when the usage ratio of the IGCT submodule is less than the preset replacement ratio, the harmonic increase problem caused by the submodule modulation is not obvious, and the same number of IGCT submodules can be directly used to replace the same number of IGBT submodules to obtain the number of IGCT single bridge arm submodules corresponding to the hybrid converter valve topology; it should be noted that the position where the IGCT submodule replaces the IGBT submodule is arbitrary, and it can be replaced in a centralized manner or in a decentralized manner. For example, taking a DC transmission project with a single valve group of ±260kV, a DC current of 2885A, a DC power of 1500MW and a pseudo-bipolar structure for the main connection as an example, if only IGBTs with a rated voltage of 2.2kV and a rated current of 3kA on the market are used, the total number of sub-modules in a single bridge arm is 238 without considering redundancy; assuming that the preset replacement ratio is 2%, when 4 IGBT sub-modules are needed in a single bridge arm, the converter valve parameters can be directly configured by equal replacement, and the parameter configuration of the hybrid converter valve topology shown in Table 1 is obtained.

[0023] Table 1 Parameter configuration of hybrid converter valve topology When the usage ratio of the IGCT submodule is greater than or equal to the preset replacement ratio, the number of the IGBT single bridge arm submodules and the number of the IGCT single bridge arm submodules are calculated based on the single valve group inter-pole voltage constraint according to the total number of the single bridge arm submodules, the rated operating voltage of the IGBT submodules and the rated operating voltage of the IGCT submodules; wherein the single valve group inter-pole voltage constraint is expressed as: In the formula, and Respectively represent the number of IGBT single bridge arm sub-modules and the number of IGCT single bridge arm sub-modules, and , Indicates the total number of single-arm submodules in the hybrid converter valve topology; and Respectively represent the rated operating voltages of the IGBT submodule and the IGCT submodule; Indicates the inter-electrode voltage of a single valve group. The IGBT submodule is usually 2.2kV or less, and the IGCT submodule is 3.1kV or less. For example, if the IGBT submodule and the IGCT submodule are added in equal proportions, U dc =520kV, then based on the above formula, we can get A=B=99, and an even number is 100, that is, when the ratio of IGBT sub-modules and IGCT sub-modules is 50% each, the corresponding number of IGBT single-bridge-arm sub-modules and IGCT single-bridge-arm sub-modules are both 100.

[0024] After the total number of single-bridge arm submodules, the number of IGBT single-bridge arm submodules, and the number of IGCT single-bridge arm submodules are determined by the above method, a hybrid converter valve topology that can be used for direct current transmission is obtained. After the hybrid converter valve topology is put into use, in order to ensure its application effect, this embodiment preferably designs different submodule input control mechanisms based on the nearest level approximation modulation principle for the use ratio of IGCT submodules in the hybrid converter valve topology. Specifically, the steps of calculating the number of upper bridge arm real-time input submodules and the number of lower bridge arm real-time input submodules in the hybrid converter valve topology based on the nearest level approximation modulation principle according to the total number of single-bridge arm submodules and the use ratio of IGCT submodules in the hybrid converter valve topology include: When the usage ratio of the IGCT submodule is less than the preset replacement ratio, the number of real-time submodules put into operation in the lower bridge arm and the number of real-time submodules put into operation in the upper bridge arm are calculated based on the first expression according to the total number of the single bridge arm submodules, the inter-pole voltage of the single valve group, the valve-side modulation wave voltage and the rated working voltage of the IGBT submodule; wherein, the first expression can be understood as a calculation formula for the optimal number of real-time submodules put into operation in the upper and lower bridge arms based on the nearest level approximation modulation principle (using the closest level or the closest voltage vector to instantaneously approximate the sinusoidal modulation wave), combined with the circuit operation mechanism of the actual hybrid converter valve topology, and considering the situation that when the usage ratio of the IGCT submodule is small, the voltage division of the replaced IGCT submodule is not much different from the voltage division of the IGBT submodule. In order to simplify the calculation complexity of the real-time operation submodule as much as possible and improve the calculation efficiency of the real-time operation submodule, this embodiment preferably uniformly adopts the rated working voltage of the IGBT submodule as the benchmark for analysis and calculation, such as Figure 1 The converter valve voltage withstand voltage is equal to U dc / 2-U v , and the total number of upper and lower bridge arms put into operation at the same time is always N, so the number of upper and lower bridge arms put into operation can be obtained, that is, the first expression is expressed as: In the formula, and They respectively represent the number of sub-modules put into use in the lower bridge arm and the number of sub-modules put into use in the upper bridge arm at time t when the usage ratio of the IGCT sub-modules is less than the preset replacement ratio; Indicates the rated operating voltage of the IGBT submodule; Indicates the inter-electrode voltage of a single valve group; Indicates the valve side modulation wave voltage; Indicates the total number of single-arm submodules.

[0025] When the usage ratio of the IGCT submodule is greater than or equal to the preset replacement ratio, the number of real-time submodules put into operation in the lower bridge arm and the number of real-time submodules put into operation in the upper bridge arm are obtained according to the total number of submodules of the single bridge arm, the preset modulation sorting strategy and the current number of submodules put into operation in the lower bridge arm; wherein the current number of submodules put into operation in the lower bridge arm can be understood as the number of submodules put into operation in the lower bridge arm in the current topology obtained relative to the time t when the number of real-time submodules put into operation in the lower bridge arm needs to be updated (the number of real-time submodules put into operation in the lower bridge arm determined by analysis at time t-1). ); The preset modulation sorting strategy can be understood as an adjustment modulation sorting strategy determined based on the modulation priority difference between the IGCT submodule and the IGBT submodule when the IGCT submodule accounts for a large proportion in the hybrid converter valve topology; in practical applications, considering that the IGCT accounts for a large proportion, the specific modulation execution will involve two different steady-state operating voltages. The preset modulation sorting strategy can be divided into two methods: 1) sort the IGBT submodule first, and then sort the IGCT submodule; 2) sort the IGCT submodule first, and then sort the IGBT submodule.

[0026] Specifically, when the preset modulation sorting strategy is to sort the IGBT submodules first and then the IGCT submodules, the IGBT submodules are put into use first, and if the required amount exceeds the total amount of the IGBT submodules, the IGCT submodules are put into use; correspondingly, according to the total number of the single bridge arm submodules, the preset modulation sorting strategy and the current number of the lower bridge arm submodules put into use, the step of obtaining the number of the lower bridge arm real-time put-in submodules and the number of the upper bridge arm real-time put-in submodules includes: When the current number of lower bridge arm submodules is less than or equal to the number of IGBT single bridge arm submodules, the number of lower bridge arm real-time submodules and the number of upper bridge arm real-time submodules are calculated based on the first expression according to the total number of single bridge arm submodules, the single valve group inter-electrode voltage, the valve side modulation wave voltage and the rated working voltage of the IGBT submodule; that is, the current number of lower bridge arm submodules The number of IGBT single bridge arm sub-modules does not exceed ( ), the number of sub-modules put into operation in the lower bridge arm at time t (IGBT sub-modules put into operation) is calculated based on the nearest level approximation modulation principle and is expressed as: In the formula, Indicates that the IGBT sub-modules are sorted first. When the number of sub-modules put into operation in the lower bridge arm is less than or equal to the number of sub-modules in the IGBT single bridge arm, the number of sub-modules put into operation in the lower bridge arm at time t in real time; Indicates the rated operating voltage of the IGBT submodule; Indicates the inter-electrode voltage of a single valve group; Indicates the valve side modulation wave voltage.

[0027] The total number of submodules in the lower bridge arm and the upper bridge arm at any time must be equal to the total number of submodules in a single bridge arm. According to the principle, the real-time number of sub-modules put into use in the upper bridge arm at time t (put into IGBT sub-modules) can be expressed as: In the formula, Indicates the total number of single bridge arm submodules; It means that the IGBT sub-modules are sorted first. When the number of sub-modules put into operation in the lower bridge arm is less than or equal to the number of sub-modules put into operation in the IGBT single bridge arm, the number of sub-modules put into operation in the lower bridge arm and the number of sub-modules put into operation in the upper bridge arm are calculated at time t.

[0028] When the current number of lower bridge arm submodules is greater than the number of IGBT single bridge arm submodules and the current number of lower bridge arm submodules is less than the total number of single bridge arm submodules, the number of lower bridge arm real-time submodules and the number of upper bridge arm real-time submodules are calculated based on the second expression according to the total number of single bridge arm submodules, the single valve group inter-electrode voltage, the valve-side modulation wave voltage, the rated operating voltage of the IGBT submodule, the number of IGBT single bridge arm submodules and the rated operating voltage of the IGCT submodule; wherein the second expression can be understood as when When the number of sub-modules put into operation in the lower bridge arm is greater than the number of sub-modules in the IGBT single bridge arm, the expression for calculating the number of sub-modules put into operation in the upper and lower bridge arms at time t (putting into the IGCT sub-module) is expressed as: In the formula, and They respectively indicate that the usage ratio of IGCT submodules is greater than or equal to the preset replacement ratio, and the IGBT submodules are sorted first. When the number of submodules put into use in the lower bridge arm is greater than the number of IGBT single bridge arm submodules, the number of submodules put into use in the lower bridge arm and the number of submodules put into use in the upper bridge arm at time t; Indicates the rated operating voltage of the IGCT submodule; Indicates the number of IGBT single bridge arm sub-modules.

[0029] When the preset modulation sorting strategy is to sort the IGCT submodules first and then the IGBT submodules, the IGCT submodules are put into use first, and if the required amount exceeds the total amount of the IGCT submodules, the IGBT submodules are put into use; correspondingly, according to the total number of the single bridge arm submodules, the preset modulation sorting strategy and the current number of the lower bridge arm submodules put into use, the step of obtaining the number of the lower bridge arm real-time put-in submodules and the number of the upper bridge arm real-time put-in submodules includes: When the current number of lower bridge arm submodules is less than or equal to the number of IGCT single bridge arm submodules, the number of lower bridge arm real-time submodules and the number of upper bridge arm real-time submodules are calculated based on the third expression according to the total number of single bridge arm submodules, the single valve group inter-electrode voltage, the valve side modulation wave voltage and the rated working voltage of the IGCT submodule; wherein the third expression can be understood as when When the number of submodules put into operation in the lower bridge arm does not exceed the number of submodules in the IGCT single bridge arm, the expression for calculating the number of submodules put into operation in the upper and lower bridge arms at time t (put into IGCT submodules) is based on the nearest level approximation modulation principle, which is expressed as: In the formula, and They respectively indicate that the usage ratio of IGCT submodules is greater than or equal to the preset replacement ratio. The IGCT submodules are sorted first. When the number of submodules put into use in the lower bridge arm is less than or equal to the number of submodules in the IGCT single bridge arm, the number of submodules put into use in the lower bridge arm and the number of submodules put into use in the upper bridge arm at time t are real-time; Respectively represent the rated operating voltage of the IGCT sub-module.

[0030] When the current number of lower bridge arm submodules is greater than the number of IGCT single bridge arm submodules and the current number of lower bridge arm submodules is less than the total number of single bridge arm submodules, the number of lower bridge arm real-time submodules and the number of upper bridge arm real-time submodules are calculated based on the fourth expression according to the total number of single bridge arm submodules, the single valve group inter-pole voltage, the valve-side modulation wave voltage, the rated operating voltage of the IGBT submodule, the number of IGCT single bridge arm submodules and the rated operating voltage of the IGCT submodule; wherein the fourth expression can be understood as when (When the number of sub-modules put into operation in the lower bridge arm exceeds the number of sub-modules in the IGCT single bridge arm), the expression for calculating the number of sub-modules put into operation in the upper and lower bridge arms at time t (putting into operation in IGBT sub-modules) is expressed as: In the formula, and They respectively indicate that the usage ratio of IGCT submodules is greater than or equal to the preset replacement ratio. The IGCT submodules are sorted first. When the number of submodules put into use in the lower bridge arm is greater than the number of submodules in the IGCT single bridge arm, the number of submodules put into use in the lower bridge arm and the number of submodules put into use in the upper bridge arm at time t are real-time; Indicates the number of IGCT single bridge arm submodules.

[0031] Through the above method steps, the IGBT submodule and the IGCT submodule in the hybrid converter valve topology can be scientifically and reasonably modulated and controlled based on the nearest level approximation modulation principle, providing reliable guarantee for the stable operation of the hybrid converter valve topology.

[0032] S12, performing power transmission control according to the real-time number of sub-modules put into operation in the upper bridge arm and the real-time number of sub-modules put into operation in the lower bridge arm; wherein, power transmission control can be understood as the number of sub-modules that need to be put into operation in the upper and lower bridge arms is calculated, and the on-off of the sub-modules is controlled by triggering pulses to execute the corresponding voltage modulation strategy. The specific implementation of power transmission control according to the real-time number of sub-modules put into operation in the upper bridge arm and the real-time number of sub-modules put into operation in the lower bridge arm can be referred to the relevant existing technology, which will not be described in detail here.

[0033] The embodiment of the present invention uses a plurality of IGBT submodules and IGCT submodules in series and adopts a pseudo bipolar structure as the main wiring design to obtain a hybrid converter valve topology. According to the total number of single bridge arm submodules and the use ratio of IGCT submodules in the hybrid converter valve topology, the number of upper bridge arm real-time input submodules and the number of lower bridge arm real-time input submodules in the hybrid converter valve topology are calculated based on the nearest level approximation modulation principle, and the power transmission control scheme is executed according to the number of upper bridge arm real-time input submodules and the number of lower bridge arm real-time input submodules, which effectively solves the existing IGBT The application defects of the converter valve are eliminated. Based on the configuration ratio of the IGBT sub-module and the IGCT sub-module in the hybrid converter valve topology and the principle of nearest level approximation modulation, the hybrid converter valve topology can be reliably and stably controlled for power transmission. The flexible ratio of the IGBT sub-module and the IGCT sub-module can be used to realize the complementary advantages of the insulated gate bipolar transistor and the integrated gate-commutated thyristor, which can not only ensure the DC transmission performance of the transmission system, but also greatly reduce the construction cost of the flexible DC converter station, thereby effectively improving the economy of the flexible DC transmission technology in large-scale new energy DC transmission scenarios.

[0034] In order to verify the effectiveness of the power transmission control method of the hybrid converter valve topology proposed in the present invention, this embodiment also verifies the flexible DC transient and steady-state characteristics by building a hybrid converter valve topology flexible DC transmission system based on the PSCAD (Power System Computer Aided Design) model, wherein the DC bus voltage is 520 kV, the number of single bridge arm modules is 234 (IGBT, 2.2 kV) + 4 (IGCT, 3.1 kV), and the single bridge arm submodules numbered 1-4 are set as IGCT modules, and the single bridge arm submodules numbered 5-238 are set as IGBT modules, and the result is Figure 3-Figure 6 The verification results are shown. Figure 3 From the steady-state waveform of the hybrid converter valve topology in the flexible DC transmission system shown in the figure, it can be seen that the steady-state waveform of the hybrid converter valve is stable, indicating that the hybrid mode is feasible; based on Figure 4 The operating waveform of the hybrid converter valve topology obtained by simulating an AC three-phase grounding fault with a duration of 100ms as shown in the figure shows that after the fault is cleared, the DC power and DC current of the flexible DC system are restored, and the transient characteristics are in line with expectations; Figure 5The operation waveform of the hybrid converter valve topology obtained by simulating a three-phase grounding fault on the valve side with a duration of 100ms shows that after the fault, the flexible DC system overcurrent, DC blocking, and transient characteristics are in line with expectations; based on Figure 6 The operating waveform of the hybrid converter valve topology obtained by simulating a DC positive pole grounding fault with a duration of 100ms shows that the flexible DC system overcurrent, DC blocking, and transient characteristics are in line with expectations; in addition, by comparing Figure 4-Figure 6 It can be seen that the overall change trends of the IGBT sub-module and the IGCT sub-module under different fault conditions are consistent, and have good stability.

[0035] It should be noted that although the steps in the above flowchart are shown in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders.

[0036] In one embodiment, Figure 7 As shown, a power transmission control system of a hybrid converter valve topology is provided, wherein the hybrid converter valve topology includes a plurality of IGBT submodules and IGCT submodules connected in series; the main connection of the hybrid converter valve topology adopts a pseudo bipolar structure; the system includes: Submodule input analysis module 1, used to calculate the number of upper bridge arm real-time input submodules and the number of lower bridge arm real-time input submodules in the hybrid converter valve topology based on the nearest level approximation modulation principle according to the total number of single bridge arm submodules and the usage ratio of IGCT submodules in the hybrid converter valve topology; The power transmission control module 2 is used to perform power transmission control according to the number of sub-modules put into operation in real time in the upper bridge arm and the number of sub-modules put into operation in real time in the lower bridge arm.

[0037] For the specific definition of the power transmission control system of the hybrid converter valve topology, please refer to the definition of the power transmission control method of the hybrid converter valve topology above, and the corresponding technical effects can also be obtained equivalently, which will not be repeated here. Each module in the power transmission control system of the above-mentioned hybrid converter valve topology can be implemented in whole or in part by software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0038] Figure 8 FIG. 1 shows an internal structure diagram of a computer device in an embodiment, and the computer device may specifically be a terminal or a server. Figure 8As shown, the computer device includes a processor, a memory, a network interface, a display, a camera and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a power transmission control method of a hybrid converter valve topology is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a key, trackball or touchpad set on the computer device housing, or an external keyboard, touchpad or mouse, etc.

[0039] It can be understood by those skilled in the art that Figure 8 The structure shown in the figure is only a block diagram of a part of the structure related to the scheme of the present invention, and does not constitute a limitation on the computer device to which the scheme of the present invention is applied. The specific computing device may include more or less components than those shown in the figure, or combine certain components, or have the same component arrangement.

[0040] In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the steps of the above method are implemented when the processor executes the computer program.

[0041] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the above method are implemented.

[0042] In summary, the embodiment of the present invention provides a power transmission control method and system for a hybrid converter valve topology. The power transmission control method for the hybrid converter valve topology realizes the use of several IGBT sub-modules and IGCT sub-modules in series, and adopts a pseudo-bipolar structure as the main wiring design to obtain a hybrid converter valve topology. According to the total number of single-arm sub-modules and the use ratio of IGCT sub-modules in the hybrid converter valve topology, the number of upper bridge arm real-time input sub-modules and the number of lower bridge arm real-time input sub-modules in the hybrid converter valve topology are calculated based on the nearest level approximation modulation principle, and the technical solution of power transmission control is executed according to the number of upper bridge arm real-time input sub-modules and the number of lower bridge arm real-time input sub-modules. The method can realize the complementary advantages of insulated gate bipolar transistors and integrated gate-commutated thyristors based on the flexible ratio of IGBT sub-modules and IGCT sub-modules, which can not only ensure the DC transmission performance of the transmission system, but also greatly reduce the construction cost of the flexible DC converter station, thereby effectively improving the economy of the flexible DC transmission technology in large-scale new energy DC transmission scenarios.

[0043] Each embodiment in this specification is described in a progressive manner, and the same or similar parts of each embodiment can be directly referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. It should be noted that the technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0044] The above-mentioned embodiments only express several preferred implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principle of the present invention, and these improvements and substitutions should also be regarded as the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the protection scope of the claims.

Claims

1. A power transmission control method for a hybrid converter valve topology, characterized in that: The hybrid converter valve topology includes a plurality of IGBT submodules and IGCT submodules connected in series; the main connection of the hybrid converter valve topology adopts a pseudo-bipolar structure; the method includes the following steps: According to the total number of single-bridge-arm submodules and the usage ratio of IGCT submodules in the hybrid converter valve topology, the number of upper-bridge-arm real-time put-into-use submodules and the number of lower-bridge-arm real-time put-into-use submodules in the hybrid converter valve topology are calculated based on the nearest level approximation modulation principle; Power transmission control is performed according to the number of submodules put into operation in real time in the upper bridge arm and the number of submodules put into operation in real time in the lower bridge arm.

2. The power transmission control method of the hybrid converter valve topology according to claim 1, characterized in that: The total number of single-arm submodules in the hybrid converter valve topology is calculated based on the target flexible DC output voltage, the voltage of a single submodule and Kirchhoff's voltage law.

3. The power transmission control method of the hybrid converter valve topology according to claim 2, characterized in that: The number of IGBT single-bridge arm submodules and the number of IGCT single-bridge arm submodules in the hybrid converter valve topology are determined by the following steps: When the usage ratio of the IGCT submodule is less than the preset replacement ratio, the number of the IGCT single bridge arm submodules is obtained based on the product of the total number of the single bridge arm submodules and the usage ratio of the IGCT submodules, and the number of the IGBT single bridge arm submodules is obtained according to the difference between the total number of the single bridge arm submodules and the number of the IGCT single bridge arm submodules; When the usage ratio of the IGCT sub-module is greater than or equal to the preset replacement ratio, the number of the IGBT single bridge arm sub-modules and the number of the IGCT single bridge arm sub-modules are calculated based on the single valve group inter-pole voltage constraint according to the total number of the single bridge arm sub-modules, the rated operating voltage of the IGBT sub-modules and the rated operating voltage of the IGCT sub-modules.

4. The power transmission control method of the hybrid converter valve topology according to claim 3, characterized in that: The inter-electrode voltage constraint of the single valve group is expressed as: In the formula, and Respectively represent the number of IGBT single bridge arm submodules and the number of IGCT single bridge arm submodules; and Respectively represent the rated operating voltages of the IGBT submodule and the IGCT submodule; Indicates the inter-electrode voltage of a single valve group.

5. The power transmission control method of the hybrid converter valve topology according to claim 1, characterized in that: The step of calculating the number of upper bridge arm real-time input submodules and the number of lower bridge arm real-time input submodules in the hybrid converter valve topology based on the nearest level approximation modulation principle according to the total number of single bridge arm submodules and the usage ratio of IGCT submodules in the hybrid converter valve topology comprises: When the usage ratio of the IGCT submodule is less than the preset replacement ratio, the number of the lower bridge arm real-time put-in-place submodules and the number of the upper bridge arm real-time put-in-place submodules are calculated based on the first expression according to the total number of the single bridge arm submodules, the inter-electrode voltage of the single valve group, the valve-side modulation wave voltage and the rated working voltage of the IGBT submodule; the first expression is expressed as: In the formula, and They respectively represent the number of sub-modules put into use in the lower bridge arm and the number of sub-modules put into use in the upper bridge arm at time t when the usage ratio of the IGCT sub-modules is less than the preset replacement ratio; Indicates the rated operating voltage of the IGBT submodule; Indicates the inter-electrode voltage of a single valve group; Indicates the valve side modulation wave voltage; Indicates the total number of single bridge arm submodules; When the usage ratio of the IGCT sub-module is greater than or equal to the preset replacement ratio, the number of lower bridge arm real-time put-in-place sub-modules and the number of upper bridge arm real-time put-in-place sub-modules are obtained according to the total number of single bridge arm sub-modules, the preset modulation sorting strategy and the current number of lower bridge arm put-in-place sub-modules.

6. The power transmission control method of the hybrid converter valve topology according to claim 5, characterized in that: When the preset modulation sorting strategy is to sort the IGBT submodules first and then sort the IGCT submodules, the step of obtaining the number of lower bridge arm real-time put-in-place submodules and the number of upper bridge arm real-time put-in-place submodules according to the total number of single bridge arm submodules, the preset modulation sorting strategy and the current number of lower bridge arm put-in-place submodules includes: When the current number of lower bridge arm submodules is less than or equal to the number of IGBT single bridge arm submodules, the number of lower bridge arm real-time submodules and the number of upper bridge arm real-time submodules are calculated based on the first expression according to the total number of single bridge arm submodules, the single valve group inter-electrode voltage, the valve side modulation wave voltage and the rated working voltage of the IGBT submodule; When the current number of lower bridge arm submodules put into operation is greater than the number of IGBT single bridge arm submodules and the current number of lower bridge arm submodules put into operation is less than the total number of single bridge arm submodules, the number of lower bridge arm real-time submodules put into operation and the number of upper bridge arm real-time submodules put into operation are calculated based on the second expression according to the total number of single bridge arm submodules, the inter-electrode voltage of the single valve group, the valve-side modulation wave voltage, the rated operating voltage of the IGBT submodule, the number of IGBT single bridge arm submodules and the rated operating voltage of the IGCT submodule; the second expression is expressed as: In the formula, and They respectively indicate that the usage ratio of IGCT submodules is greater than or equal to the preset replacement ratio, and the IGBT submodules are sorted first. When the number of submodules put into use in the lower bridge arm is greater than the number of IGBT single bridge arm submodules, the number of submodules put into use in the lower bridge arm and the number of submodules put into use in the upper bridge arm at time t; Indicates the rated operating voltage of the IGCT submodule; Indicates the number of IGBT single bridge arm sub-modules.

7. The power transmission control method of the hybrid converter valve topology according to claim 5, characterized in that: When the preset modulation sorting strategy is to sort the IGCT submodules first and then sort the IGBT submodules, the step of obtaining the number of lower bridge arm real-time put-in-place submodules and the number of upper bridge arm real-time put-in-place submodules according to the total number of single bridge arm submodules, the preset modulation sorting strategy and the current number of lower bridge arm put-in-place submodules includes: When the current number of lower bridge arm submodules is less than or equal to the number of IGCT single bridge arm submodules, the number of lower bridge arm real-time submodules and the number of upper bridge arm real-time submodules are calculated based on the third expression according to the total number of single bridge arm submodules, the single valve group inter-electrode voltage, the valve-side modulation wave voltage and the rated working voltage of the IGCT submodule; the third expression is expressed as: In the formula, and They respectively indicate that the usage ratio of IGCT submodules is greater than or equal to the preset replacement ratio. The IGCT submodules are sorted first. When the number of submodules put into use in the lower bridge arm is less than or equal to the number of submodules in the IGCT single bridge arm, the number of submodules put into use in the lower bridge arm and the number of submodules put into use in the upper bridge arm at time t are real-time; Respectively represent the rated operating voltage of the IGCT submodule; When the current number of lower bridge arm submodules put into operation is greater than the number of IGCT single bridge arm submodules and the current number of lower bridge arm submodules put into operation is less than the total number of single bridge arm submodules, the number of lower bridge arm real-time submodules put into operation and the number of upper bridge arm real-time submodules put into operation are calculated based on the fourth expression according to the total number of single bridge arm submodules, the single valve group inter-electrode voltage, the valve-side modulation wave voltage, the rated operating voltage of the IGBT submodule, the number of IGCT single bridge arm submodules and the rated operating voltage of the IGCT submodule; the fourth expression is expressed as: In the formula, and They respectively indicate that the usage ratio of IGCT submodules is greater than or equal to the preset replacement ratio. The IGCT submodules are sorted first. When the number of submodules put into use in the lower bridge arm is greater than the number of submodules in the IGCT single bridge arm, the number of submodules put into use in the lower bridge arm and the number of submodules put into use in the upper bridge arm at time t are real-time; Indicates the number of IGCT single bridge arm submodules.

8. A power transmission control system with a hybrid converter valve topology, characterized in that: The hybrid converter valve topology includes a plurality of IGBT submodules and IGCT submodules connected in series; the main connection of the hybrid converter valve topology adopts a pseudo-bipolar structure; the system includes: A submodule input analysis module is used to calculate the number of real-time input submodules of the upper bridge arm and the number of real-time input submodules of the lower bridge arm in the hybrid converter valve topology based on the nearest level approximation modulation principle according to the total number of single bridge arm submodules and the usage ratio of IGCT submodules in the hybrid converter valve topology; The power transmission control module is used to perform power transmission control according to the number of sub-modules put into operation in real time in the upper bridge arm and the number of sub-modules put into operation in real time in the lower bridge arm.

9. 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, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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