Dynamic aggregation method for reactive power control of flexible direct-current traction power supply system and related device

Abstract

The invention discloses a dynamic aggregation method for reactive power control of a flexible direct-current traction power supply system and a related device. The method comprises the following steps: establishing a reactive power control model of a flexible direct-current converter in the flexible direct-current traction power supply system; the q-axis current of the flexible direct current converter is aggregated; aggregating the output reactive power of the flexible direct-current converter; and substituting a q-axis current aggregation result and an output reactive power aggregation result of the flexible DC converter into the reactive power control model to obtain a dynamic aggregation parameter. According to the method, the defects of a linear time-invariant aggregation model in coping with a rapidly changing power grid state can be overcome, and the response speed and accuracy of a control system are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of reactive power control of a flexible DC traction power supply system, and in particular relates to a dynamic aggregation method and related devices for reactive power control of a flexible DC traction power supply system. Background Art

[0002] With the rapid development of urban rail transit systems, flexible DC traction power supply systems have been widely used due to their high efficiency and flexibility. The system uses voltage source converters (VSCs) as core equipment, and through dq decoupling control technology, it can achieve bidirectional four-quadrant operation of active and reactive power, thereby ensuring normal power supply while providing necessary reactive power compensation for the power grid. Especially when the power grid voltage drops due to faults and other reasons, VSC can respond quickly, provide reactive power support for the power grid, effectively maintain the stability of the power grid voltage, and ensure the normal operation of urban rail transit systems such as subways.

[0003] In practical applications, a subway line is often equipped with multiple VSC converters to achieve long-distance, high-power power transmission. If these converters are to be controlled uniformly, a complex communication network and a powerful central processor are needed to support them. This will not only increase the communication burden, but also increase the computing pressure of the central processor, resulting in longer acquisition and processing time for each reactive power control instruction. For fast voltage control under transient time scales, this delay is unacceptable because it may directly affect the stability and security of the power grid.

[0004] In order to reduce the complexity of the control model and speed up the algorithm solution, the aggregation method came into being. The aggregation method aggregates controllers with similar or similar dynamic characteristics into a whole, thereby greatly reducing the number of objects that the central controller needs to directly control and achieving dimensionality reduction of the control model. This method can theoretically improve the response speed of the control system and meet the control requirements of the transient time scale. However, most of the existing aggregation models use a linear time-invariant model, which is obtained by aggregation based on the state of the converter at a specific moment. Therefore, it requires that the state of the converter cannot change significantly during the entire control process, otherwise the aggregation model will fail. However, in the urban rail flexible DC traction power supply system for transient voltage control, due to the rapid change of the power grid state, the operating state of the VSC converter is also in dynamic adjustment at all times. Therefore, the conventional linear time-invariant aggregation model cannot adapt to this rapidly changing environment and is difficult to meet the control requirements of the system. Summary of the invention

[0005] In response to the problems existing in the prior art, the present invention provides a dynamic aggregation method and related devices for reactive power control of a flexible DC traction power supply system, which can overcome the shortcomings of the linear time-invariant aggregation model in dealing with rapidly changing grid conditions and improve the response speed and accuracy of the control system.

[0006] In order to solve the above technical problems, the present invention is implemented by the following technical solutions:

[0007] According to a first aspect of the present invention, a dynamic aggregation method for reactive power control of a flexible DC traction power supply system is provided, comprising:

[0008] Establish the reactive power control model of flexible DC converter in flexible DC traction power supply system;

[0009] Aggregating the q-axis current of the flexible DC converter;

[0010] Aggregate the output reactive power of the flexible DC converter;

[0011] Substitute the q-axis current aggregation result and the output reactive power aggregation result of the flexible DC converter into the reactive power control model to obtain dynamic aggregation parameters.

[0012] In a possible implementation manner of the first aspect, the reactive power control model is:

[0013]

[0014] Where, T q is the q-axis inertia time constant of the flexible DC converter; Δi q is the change of the q-axis current of the flexible DC converter; k p and k i is the PI parameter of the reactive power control loop; ΔQ ref is the change in the reactive power command output by the flexible DC converter; Q is the change in the actual reactive power output by the flexible DC converter.

[0015] In a possible implementation manner of the first aspect, aggregating the q-axis current of the flexible DC converter is specifically:

[0016]

[0017] Wherein, α1 and α2 are the angle differences between the coordinate axes of the first flexible DC converter and the second flexible DC converter and the common coordinate axis; Δi qc1 and Δi qc2 is the change in the q-axis current of the first flexible DC converter and the second flexible DC converter; Δi q is the aggregate value of q-axis current.

[0018] In a possible implementation manner of the first aspect, the aggregating the output reactive power of the flexible DC converter is specifically:

[0019]

[0020] Where V c1 and V c2 is the AC measured voltage of the first flexible DC converter and the second flexible DC converter; Q1 and Q2 are the output reactive power of the first flexible DC converter and the second flexible DC converter; ΔQ1 and ΔQ2 are the changes in the output reactive power of the first flexible DC converter and the second flexible DC converter; X1 and X2 are the reactances of the cables connecting the first flexible DC converter and the second flexible DC converter to the grid; ΔQ is the output reactive aggregation value.

[0021] In a possible implementation of the first aspect, the q-axis current aggregation result and the output reactive power aggregation result of the flexible DC converter are substituted into the reactive power control model to obtain a dynamic aggregation parameter, which is specifically:

[0022]

[0023] A=[cosα1cosα2]

[0024]

[0025] In the formula, k pc1 and k ci1 is the PI control parameter of the first flexible DC converter; k pc2 and k ci2 is the PI control parameter of the second flexible DC converter.

[0026] According to a second aspect of the present invention, a dynamic aggregation device for reactive power control of a flexible DC traction power supply system is provided, comprising:

[0027] Establishing a module for establishing a reactive power control model of a flexible DC converter in a flexible DC traction power supply system;

[0028] A first aggregation module, used for aggregating the q-axis current of the flexible DC converter;

[0029] A second aggregation module is used to aggregate the output reactive power of the flexible DC converter;

[0030] The substitution module is used to substitute the q-axis current aggregation result and the output reactive power aggregation result of the flexible DC converter into the reactive power control model to obtain dynamic aggregation parameters.

[0031] In a possible implementation manner of the second aspect, the reactive power control model is:

[0032]

[0033] Where, T q is the q-axis inertia time constant of the flexible DC converter; Δi q is the change of the q-axis current of the flexible DC converter; k p and k i is the PI parameter of the reactive power control loop; ΔQ ref is the change in the reactive power command output by the flexible DC converter; Q is the change in the reactive power actually output by the flexible DC converter;

[0034] The aggregating of the q-axis current of the flexible DC converter is specifically:

[0035]

[0036] Wherein, α1 and α2 are the angle differences between the coordinate axes of the first flexible DC converter and the second flexible DC converter and the common coordinate axis; Δi qc1 and Δi qc2 is the change in the q-axis current of the first flexible DC converter and the second flexible DC converter; Δi q is the aggregate value of q-axis current;

[0037] The aggregating the output reactive power of the flexible DC converter is specifically as follows:

[0038]

[0039] Where V c1 and V c2 is the AC measured voltage of the first flexible DC converter and the second flexible DC converter; Q1 and Q2 are the output reactive power of the first flexible DC converter and the second flexible DC converter; ΔQ1 and ΔQ2 are the changes in the output reactive power of the first flexible DC converter and the second flexible DC converter; X1 and X2 are the reactances of the cables connecting the first flexible DC converter and the second flexible DC converter to the grid; ΔQ is the output reactive aggregation value;

[0040] Substituting the q-axis current aggregation result and the output reactive power aggregation result of the flexible DC converter into the reactive power control model to obtain the dynamic aggregation parameters is specifically:

[0041]

[0042] A=[cosα1cosα2]

[0043]

[0044] In the formula, k pc1 and kci1 is the PI control parameter of the first flexible DC converter; k pc2 and k ci2 is the PI control parameter of the second flexible DC converter.

[0045] According to a third aspect of the present invention, there is provided a device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the dynamic aggregation method for reactive power control of a flexible DC traction power supply system is implemented.

[0046] According to a fourth aspect of the present invention, there is provided a computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the dynamic aggregation method for reactive power control of a flexible DC traction power supply system.

[0047] According to a fifth aspect of the present invention, a computer program product is provided, which, when executed by a processor, implements the dynamic aggregation method for reactive power control of a flexible DC traction power supply system.

[0048] Compared with the prior art, the present invention has at least the following beneficial effects:

[0049] The present invention provides a dynamic aggregation method for reactive power control of a flexible DC traction power supply system, establishes a reactive power control model of a flexible DC converter in the flexible DC traction power supply system, aggregates the q-axis current of the flexible DC converter, and aggregates the output reactive power of the flexible DC converter, and finally substitutes the q-axis current aggregation result and the output reactive aggregation result of the flexible DC converter into the reactive power control model to obtain dynamic aggregation parameters. This dynamic aggregation parameter obtained by mathematical derivation is a linear time-varying model that can accurately characterize the external characteristics of the flexible DC traction power supply system and can be updated according to the real-time state of the flexible DC converter, thereby achieving rapid response and precise adjustment of the reactive power control of the system. Compared with the traditional linear time-invariant aggregation model, the method of the present invention can better adapt to the rapid changes in the state of the power grid and effectively improve the response speed and accuracy of the control system. The method of the present invention realizes that by aggregating controllers with similar or close dynamic characteristics into a whole, the number of objects that the central controller needs to directly control is greatly reduced, and the dimension reduction of the control model is achieved. It not only simplifies the structure of the control system, but also reduces the computing pressure of the central processing unit, so that the acquisition and processing time of each reactive control instruction is greatly shortened, and for the rapid voltage control under the transient time scale, it can ensure the stable operation of urban rail transit systems such as subways. The dynamic aggregation method proposed in the present invention does not use approximate processing, and can retain the dynamic characteristics of the original model to the maximum extent. At the same time, because the calculation process of the aggregation parameters is completely linear and the required calculation time is very short, it can be corrected in real time according to the current operating state of the flexible DC traction power supply system, so that the aggregation model can be applied to any operating state, enhancing the adaptability of the system.

[0050] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions in the specific implementation modes of the present invention, the drawings required for use in the description of the specific implementation modes will be briefly introduced below. Obviously, the drawings described below are some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0052] Figure 1 It is a flow chart of a dynamic aggregation method for reactive power control of a flexible DC traction power supply system according to the present invention;

[0053] Figure 2 A control loop of a flexible DC converter according to an embodiment;

[0054] Figure 3The connection relationship of the flexible DC converter of the embodiment;

[0055] Figure 4 The relationship between the coordinate system of the flexible DC converter and the public coordinate system in the embodiment. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. 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.

[0057] like Figure 1 As shown, the embodiment of the present invention provides a dynamic aggregation method for reactive power control of a flexible DC traction power supply system, which is mainly to overcome the shortcomings of the linear time-invariant aggregation model in the prior art in dealing with rapidly changing grid states and improve the response speed and accuracy of the control system. Specifically, the method includes the following steps:

[0058] Step 1: Establish a reactive power control model of the flexible DC converter in the flexible DC traction power supply system.

[0059] In one possible implementation, the reactive power control model is specifically:

[0060]

[0061] Where, T q is the q-axis inertia time constant of the flexible DC converter; Δi q is the change of the q-axis current of the flexible DC converter; k p and k i is the PI parameter of the reactive power control loop; ΔQ ref is the change in the reactive power command output by the flexible DC converter; Q is the change in the actual reactive power output by the flexible DC converter.

[0062] More specifically, the control loop of the flexible DC converter is shown in the attached Figure 2 As shown. Because the dynamic time of the current loop (10ms) is much smaller than the dynamic time of the power outer loop (100ms), when studying the dynamics of the power loop, the dynamics of the current loop can be ignored and simplified to a delay link. That is:

[0063]

[0064] Among them, i d and i q are the d-axis and q-axis currents of the flexible DC converter respectively; Td and T q are the d-axis and q-axis inertia time constants of the flexible DC converter respectively; i dref and i qref are the d-axis and q-axis current reference values ​​of the flexible DC converter respectively.

[0065] Then the q-axis control equation can be written as:

[0066]

[0067] Among them, k p and k i is the PI parameter of the reactive power control loop; Q ref is the output reactive power instruction of the flexible DC converter; Q is the reactive power actually output by the flexible DC converter.

[0068] The q-axis of the flexible DC converter is modeled with small signals. During the modeling process, the inner current loop is replaced by a first-order delay link, which is:

[0069]

[0070] Step 2: Aggregate the q-axis current of the flexible DC converter.

[0071] Specifically, in order to aggregate the reactive power control model, the most important thing is to control the control quantity ΔQ ref -ΔQ and state quantity Δi q First, the state quantity Δi q Aggregation is performed, assuming that the reactive power control process of the active converter remains unchanged, then:

[0072]

[0073] Wherein, α1 and α2 are the angle differences between the coordinate axes of the first flexible DC converter and the second flexible DC converter and the common coordinate axis; Δi qc1 and Δi qc2 is the change in the q-axis current of the first flexible DC converter and the second flexible DC converter; Δi q is the aggregate value of q-axis current.

[0074] More specifically, the aggregation of two flexible DC converters is used as an example for explanation, and the aggregation process of multiple flexible DC converters can be deduced in the same way. Figure 3 shown.

[0075] Each flexible DC converter establishes a dq rotating coordinate system through a phase-locked loop (PLL). For convenience, the d-axis is generally set to be the same as the AC side voltage V cOverlap. The grid-following converter is equivalent to a current source, which outputs reactive current. Therefore, the aggregation of two flexible DC converters mainly considers the sum of currents. A common dq rotating coordinate system is established at the common point. The relationship between the converter coordinate system and the common coordinate system is shown in the attached Figure 4 As shown. The angle difference α1 and α2 between them is equal to the AC side voltage V of the flexible DC converter c and the common point voltage V ppc .The phase difference between them.

[0076] Convert the converter coordinate system to the common coordinate system, and the q-axis current is:

[0077] i q =cosα1i c1q +sinα1i c2q +cosα1i c1d +sinα2i c2d

[0078] Among them, i c1d and i c1q are the d-axis and q-axis currents of the first flexible DC converter respectively; i c2d and i c2q are the d-axis and q-axis currents of the second flexible DC converter respectively.

[0079] Assuming that the active current remains unchanged during reactive power control, the small-signal q-axis current aggregation result is:

[0080]

[0081] Step 3: Aggregate the output reactive power of the flexible DC converter.

[0082] Specifically, the control quantity ΔQ ref -ΔQ is aggregated, and it is also assumed that the reactive power control process of the active converter remains unchanged, then:

[0083]

[0084] Where V c1 and V c2 is the AC measured voltage of the first flexible DC converter and the second flexible DC converter; Q1 and Q2 are the output reactive power of the first flexible DC converter and the second flexible DC converter; ΔQ1 and ΔQ2 are the changes in the output reactive power of the first flexible DC converter and the second flexible DC converter; X1 and X2 are the reactances of the cables connecting the first flexible DC converter and the second flexible DC converter to the grid; ΔQ is the output reactive aggregation value.

[0085] More specifically, the loss of the flexible DC converter output reactive power on the line is:

[0086]

[0087] Among them, Q loss is the total reactive transmission loss.

[0088] Assuming that the active current remains unchanged during reactive power control, the result of small signal conversion is:

[0089]

[0090] Therefore, the output of the reactive aggregation result is:

[0091]

[0092] Step 4: Substitute the q-axis current aggregation result and the output reactive power aggregation result of the flexible DC converter into the reactive power control model to obtain dynamic aggregation parameters.

[0093] Specifically, the final aggregation model can be obtained by obtaining the aggregation of the control quantity and the state quantity. The structure of the aggregation model is completely consistent with the reactive power control structure of a single flexible DC converter, and the dynamic aggregation parameter calculation method is:

[0094]

[0095] Among them, the matrices A, B, C, and D are defined as:

[0096] A=[cosα1cosα2]

[0097]

[0098]

[0099] In the formula, k pc1 and k ci1 is the PI control parameter of the first flexible DC converter; k pc2 and k ci2 is the PI control parameter of the second flexible DC converter.

[0100] More specifically, in order to ensure the consistency of the model structure before and after aggregation, the aggregation model is:

[0101]

[0102] The relationship between the q-axis aggregate current and the output reactive power of the flexible DC converter is:

[0103]

[0104] Among them, matrices A and B are defined as follows:

[0105] A=[cosα1cosα1]

[0106]

[0107] Reactive power after aggregation (ΔQ ref -ΔQ) and the reactive power output of the first flexible DC converter and the second flexible DC converter (ΔQ ref1 -ΔQ1), (ΔQ ref2 -ΔQ2) can be expressed as:

[0108] ΔQ ref -ΔQ=C 11 (ΔQ ref1 -ΔQ1)+C 22 (ΔQ ref2 -ΔQ2)

[0109] Among them, C 11 and C 22 are the diagonal elements of matrix C respectively. Matrix C is:

[0110]

[0111] Because C 11 and C 22 It is approximately equal to 1, and the change in reactive power output of the flexible DC converter is basically proportional to its output reactive power:

[0112]

[0113] So we have:

[0114]

[0115] Define the matrix D:

[0116]

[0117] Flexible DC converter output reactive power (ΔQ ref1 -ΔQ1), (ΔQ ref2 -ΔQ2) and the reactive power after aggregation (ΔQ ref -ΔQ) can be expressed as:

[0118]

[0119] Therefore, the aggregation model can be expressed as:

[0120]

[0121] Split the matrix B into the P parameter part Bp and I parameter part B i :

[0122]

[0123] Therefore, the aggregation parameter k p and k i for:

[0124]

[0125] The embodiment of the present invention provides a dynamic aggregation device for reactive power control of a flexible DC traction power supply system, comprising:

[0126] A module is established to establish a reactive power control model of a flexible DC converter in a flexible DC traction power supply system.

[0127] Specifically, the reactive power control model is:

[0128]

[0129] Where, T q is the q-axis inertia time constant of the flexible DC converter; Δi q is the change of the q-axis current of the flexible DC converter; k p and k i is the PI parameter of the reactive power control loop; ΔQ ref is the change in the reactive power command output by the flexible DC converter; Q is the change in the actual reactive power output by the flexible DC converter.

[0130] The first aggregation module is used to aggregate the q-axis current of the flexible DC converter.

[0131] Specifically, the aggregating of the q-axis current of the flexible DC converter is specifically as follows:

[0132]

[0133] Wherein, α1 and α2 are the angle differences between the coordinate axes of the first flexible DC converter and the second flexible DC converter and the common coordinate axis; Δi qc1 and Δi qc2 is the change in the q-axis current of the first flexible DC converter and the second flexible DC converter; Δi q is the aggregate value of q-axis current.

[0134] The second aggregation module is used to aggregate the output reactive power of the flexible DC converter.

[0135] Specifically, the output reactive power of the flexible DC converter is aggregated as follows:

[0136]

[0137] Where V c1 and V c2 is the AC measured voltage of the first flexible DC converter and the second flexible DC converter; Q1 and Q2 are the output reactive power of the first flexible DC converter and the second flexible DC converter; ΔQ1 and ΔQ2 are the changes in the output reactive power of the first flexible DC converter and the second flexible DC converter; X1 and X2 are the reactances of the cables connecting the first flexible DC converter and the second flexible DC converter to the grid; ΔQ is the output reactive aggregation value.

[0138] The substitution module is used to substitute the q-axis current aggregation result and the output reactive power aggregation result of the flexible DC converter into the reactive power control model to obtain dynamic aggregation parameters.

[0139] Specifically, the q-axis current aggregation result and the output reactive power aggregation result of the flexible DC converter are substituted into the reactive power control model to obtain the dynamic aggregation parameter, which is specifically:

[0140]

[0141] A=[cosα1cosα2]

[0142]

[0143] In the formula, k pc1 and k ci1 is the PI control parameter of the first flexible DC converter; k pc2 and k ci2 is the PI control parameter of the second flexible DC converter.

[0144] All relevant contents of each step involved in the aforementioned embodiment of a method for dynamic aggregation of reactive power control of a flexible DC traction power supply system can be referred to the functional description of the functional module corresponding to a dynamic aggregation device for reactive power control of a flexible DC traction power supply system in the embodiment of the present invention, and will not be repeated here. The division of modules in the embodiment of the present invention is schematic and is only a logical function division. There may be other division methods in actual implementation. In addition, each functional module in each embodiment of the present invention may be integrated into a processor, or may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated modules can be implemented in the form of hardware or in the form of software functional modules.

[0145] In another embodiment of the present invention, a computer device is provided, the computer device including a processor and a memory, the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions in a computer storage medium to implement a corresponding method flow or a corresponding function; the processor described in the embodiment of the present invention can be used for the operation of a dynamic aggregation method for reactive power control of a flexible DC traction power supply system.

[0146] In another embodiment of the present invention, the present invention further provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It can be understood that the computer-readable storage medium here can include both built-in storage media in the computer device and, of course, extended storage media supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the dynamic aggregation method for reactive power control of a flexible DC traction power supply system in the above embodiment.

[0147] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0148] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0149] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0150] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0151] The present invention also provides a computer program product, which is used to execute any of the above-mentioned methods for dynamic aggregation of reactive power control of a flexible DC traction power supply system. Since the computer program product provided by the present invention and the above-mentioned method for dynamic aggregation of reactive power control of a flexible DC traction power supply system belong to the same inventive concept, the computer program product provided by the present invention has all the advantages of the above-mentioned method for dynamic aggregation of reactive power control of a flexible DC traction power supply system, and therefore the beneficial effects of the computer program product provided by the present invention will not be described one by one here.

[0152] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0153] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A dynamic aggregation method for reactive power control of a flexible DC traction power supply system, characterized in that: include: Establish the reactive power control model of flexible DC converter in flexible DC traction power supply system; Aggregating the q-axis current of the flexible DC converter; Aggregate the output reactive power of the flexible DC converter; Substitute the q-axis current aggregation result and the output reactive power aggregation result of the flexible DC converter into the reactive power control model to obtain dynamic aggregation parameters.

2. According to claim 1, a dynamic aggregation method for reactive power control of a flexible DC traction power supply system is characterized in that: The reactive power control model is: Where, T q is the q-axis inertia time constant of the flexible DC converter; Δi q is the change of the q-axis current of the flexible DC converter; k p and k i is the PI parameter of the reactive power control loop; ΔQ ref is the change in the reactive power command output by the flexible DC converter; ΔQ is the change in the actual reactive power output by the flexible DC converter.

3. The dynamic aggregation method for reactive power control of a flexible DC traction power supply system according to claim 2 is characterized in that: The aggregating of the q-axis current of the flexible DC converter is specifically: Wherein, α1 and α2 are the angle differences between the coordinate axes of the first flexible DC converter and the second flexible DC converter and the common coordinate axis; Δi qc1 and Δi qc2 is the change in the q-axis current of the first flexible DC converter and the second flexible DC converter; Δi q is the aggregate value of q-axis current.

4. The dynamic aggregation method for reactive power control of a flexible DC traction power supply system according to claim 3 is characterized in that: The aggregating the output reactive power of the flexible DC converter is specifically as follows: Where V c1 and V c2 is the AC measured voltage of the first flexible DC converter and the second flexible DC converter; Q1 and Q2 are the output reactive power of the first flexible DC converter and the second flexible DC converter; ΔQ1 and ΔQ2 are the changes in the output reactive power of the first flexible DC converter and the second flexible DC converter; X1 and X2 are the reactances of the cables connecting the first flexible DC converter and the second flexible DC converter to the grid; ΔQ is the output reactive aggregation value.

5. The dynamic aggregation method for reactive power control of a flexible DC traction power supply system according to claim 4 is characterized in that: Substituting the q-axis current aggregation result and the output reactive power aggregation result of the flexible DC converter into the reactive power control model to obtain the dynamic aggregation parameters is specifically: A=[cosα1cosα2] In the formula, k pc1 and k ci1 is the PI control parameter of the first flexible DC converter; k pc2 and k ci2 is the PI control parameter of the second flexible DC converter.

6. A dynamic aggregation device for reactive power control of a flexible DC traction power supply system, characterized in that: include: Establishing a module for establishing a reactive power control model of a flexible DC converter in a flexible DC traction power supply system; A first aggregation module, used for aggregating the q-axis current of the flexible DC converter; A second aggregation module is used to aggregate the output reactive power of the flexible DC converter; The substitution module is used to substitute the q-axis current aggregation result and the output reactive power aggregation result of the flexible DC converter into the reactive power control model to obtain dynamic aggregation parameters.

7. The dynamic aggregation device for reactive power control of a flexible DC traction power supply system according to claim 6 is characterized in that: The reactive power control model is: Where, T q is the q-axis inertia time constant of the flexible DC converter; Δi q is the change of the q-axis current of the flexible DC converter; k p and k i is the PI parameter of the reactive power control loop; ΔQ ref is the change in the reactive power command output by the flexible DC converter; ΔQ is the change in the reactive power actually output by the flexible DC converter; The aggregating of the q-axis current of the flexible DC converter is specifically: Wherein, α1 and α2 are the angle differences between the coordinate axes of the first flexible DC converter and the second flexible DC converter and the common coordinate axis; Δi qc1 and Δi qc2 is the change in the q-axis current of the first flexible DC converter and the second flexible DC converter; Δi q is the aggregate value of q-axis current; The aggregating the output reactive power of the flexible DC converter is specifically as follows: Where V c1 and V c2 is the AC measured voltage of the first flexible DC converter and the second flexible DC converter; Q1 and Q2 are the output reactive power of the first flexible DC converter and the second flexible DC converter; ΔQ1 and ΔQ2 are the changes in the output reactive power of the first flexible DC converter and the second flexible DC converter; X1 and X2 are the reactances of the cables connecting the first flexible DC converter and the second flexible DC converter to the grid; ΔQ is the output reactive aggregation value; Substituting the q-axis current aggregation result and the output reactive power aggregation result of the flexible DC converter into the reactive power control model to obtain the dynamic aggregation parameters is specifically: A=[cosα1cosα2] In the formula, k pc1 and k ci1 is the PI control parameter of the first flexible DC converter; k pc2 and k ci2 is the PI control parameter of the second flexible DC converter.

8. A 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 dynamic aggregation method for reactive power control of a flexible DC traction power supply system as described in any one of claims 1 to 5 is implemented.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by the processor, a dynamic aggregation method for reactive power control of a flexible DC traction power supply system as described in any one of claims 1 to 5 is implemented.

10. A computer program product, characterized in that When the computer program product is executed by a processor, it implements a dynamic aggregation method for reactive power control of a flexible DC traction power supply system as described in any one of claims 1 to 5.

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