Coordinated control method and device for centralized external power supply flexible direct current traction power supply system

Abstract

The present invention relates to the field of flexible direct current traction power supply technology, and in particular to a coordinated control method and device for a centralized external power supply flexible direct current traction power supply system, the method comprising: constructing an original system model including an alternating current network and a direct current network, decomposing the original system model into a load natural distribution subsystem and a coordinated control subsystem; constructing an objective function based on circulating current suppression deviation, direct current network coordinated control subsystem loss, converter loss and alternating current network loss, and establishing a quadratic programming model according to the objective function and preset constraints; solving the quadratic programming model to obtain a coordinated current control instruction vector of the traction station, and calculating a voltage control instruction vector of the traction station, and coordinating control of the flexible direct current traction power supply system based on the voltage control instruction vector. Thus, the contradiction between low calculation efficiency and insufficient optimization effect of the prior art is solved, and efficient coordinated control that quickly responds to load changes while ensuring system performance is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible direct current traction power supply, and in particular to a coordinated control method and device for a centralized external power supply flexible direct current traction power supply system. Background Art

[0002] In urban rail transit, flexible DC traction power supply systems are widely used due to their high efficiency and flexibility.

[0003] In the field of control of flexible DC traction power supply systems, early research mainly focused on control methods based on VI external characteristic curves. For example, some documents disclose a system-level control coordination method for a flexible DC traction power supply system, which enables all traction substation converters to be controlled according to the established VI external characteristics, and the port voltage and current of each converter to operate according to a fixed relationship curve. For example, patent CN107953803A "A medium-voltage flexible DC traction power supply system and its control method" adopts an improved droop control method based on proportional integral control. By improving the voltage-current droop characteristic curve, the output voltage of the traction substation is equal to the voltage reference value. Although these methods are simple to implement, the system flow is not optimally distributed, resulting in energy consumption and other performance indicators cannot achieve the optimal effect.

[0004] Another control method for the flexible DC traction power supply system is the optimization control method. For example, Li, Hongbo et al. proposed an optimal control method for a flexible DC traction power supply system in their 2021 study. This method measures global electrical information in real time and uses a communication system to transmit the global information to a central controller. The central controller uses an optimal power flow algorithm to solve the control instructions, and then sends the control instructions to all converters through the communication system. Although this method uses optimization technology, the optimization calculation of the flexible DC traction power supply system using a centralized external power source needs to consider both the AC network and the DC network in the system, resulting in a long optimization calculation time. It is not suitable for rapid updates of control instructions in real-time operation and needs to be solved urgently. Summary of the invention

[0005] The present invention provides a coordinated control method and device for a centralized external power supply flexible direct current traction power supply system to resolve the contradiction between low computational efficiency and insufficient optimization effect in the prior art, thereby achieving efficient coordinated control that quickly responds to load changes while ensuring system performance.

[0006] The first aspect of the present invention provides a coordinated control method for a centralized external power supply flexible direct current traction power supply system, comprising the following steps:

[0007] Constructing an original system model including an AC network and a DC network, and decomposing the original system model into a load natural distribution subsystem and a coordinated control subsystem;

[0008] Constructing an objective function based on circulating current suppression deviation, DC network coordinated control subsystem loss, converter loss and AC network loss, and establishing a quadratic programming model according to the objective function and preset constraints;

[0009] Based on the load natural distribution subsystem and the cooperative control subsystem, the quadratic programming model is solved to obtain the cooperative current control command vector of the traction station, and the voltage control command vector of the traction station is calculated according to the cooperative current control command vector, and the flexible direct current traction power supply system is cooperatively controlled based on the voltage control command vector.

[0010] According to one embodiment of the present invention, the objective function is:

[0011] ;

[0012] in, is the objective function, is the circulation suppression deviation, For the DC network coordinated control subsystem losses, is the converter loss, is the AC network loss, , , , are all weight coefficients.

[0013] According to an embodiment of the present invention, the circulation suppression deviation is:

[0014] ;

[0015] in, is the circulation suppression deviation, For external power supply lines that require circulating current suppression, For external power supply line, For the external power supply line in the collaborative control subsystem j The power, It is the external power supply line in the load natural distribution subsystem. j Power;

[0016] The DC network coordinated control subsystem loss is:

[0017] ;

[0018] in, For the DC network coordinated control subsystem losses, For traction, is the number of tractions, r ci For the traction in the cooperative control subsystem i and traction station i +1 catenary resistance between r ri For the traction in the cooperative control subsystem i and traction station i +1 rail resistance between is the traction network current vector of the cooperative subsystem;

[0019] The converter loss is:

[0020] ;

[0021] in, is the converter loss, is the coefficient, For traction in DC network i Power;

[0022] The AC network loss is:

[0023] ;

[0024] in, is the AC network loss, is the branch current vector of the AC network, is the branch resistance matrix of the AC network.

[0025] According to an embodiment of the present invention, the preset constraint condition includes a voltage constraint, a converter capacity constraint and a physical constraint of the decision variable itself, wherein the voltage constraint is:

[0026] U min ≤U si ≤U max ;

[0027] in, U min is the minimum value of the traction voltage, U si For traction i The voltage, U max is the maximum value of the traction voltage;

[0028] The converter capacity constraint is:

[0029] Imin ≤ I si ≤ I max ;

[0030] in, I min is the minimum value of the traction current, I si For traction i The current, I max is the maximum value of the traction current;

[0031] The physical constraints of the decision variables themselves are:

[0032] ;

[0033] in, For the i Coordinated current control instructions for each traction station.

[0034] According to the coordinated control method of the centralized external power supply flexible direct current traction power supply system of the embodiment of the present invention, an original system model including an AC network and a DC network is constructed, and the original system model is decomposed into a load natural distribution subsystem and a coordinated control subsystem; an objective function is constructed based on the circulating current suppression deviation, the loss of the DC network coordinated control subsystem, the converter loss and the AC network loss, and a quadratic programming model is established according to the objective function and preset constraints; the quadratic programming model is solved to obtain the coordinated current control instruction vector of the traction station, and the voltage control instruction vector of the traction station is calculated according to the coordinated current control instruction vector, and the flexible direct current traction power supply system is coordinatedly controlled based on the voltage control instruction vector. In this way, the contradiction between the low calculation efficiency and the insufficient optimization effect of the prior art is solved, and efficient coordinated control that quickly responds to load changes while ensuring system performance is achieved.

[0035] A second aspect of the present invention provides a coordinated control device for a centralized external power supply flexible direct current traction power supply system, comprising:

[0036] An original system model building module is used to build an original system model including an AC network and a DC network, and decompose the original system model into a load natural distribution subsystem and a coordinated control subsystem;

[0037] A quadratic programming model building module, used to build an objective function based on circulating current suppression deviation, DC network collaborative control subsystem loss, converter loss and AC network loss, and establish a quadratic programming model according to the objective function and preset constraints;

[0038] A control module is used to solve the quadratic programming model based on the load natural distribution subsystem and the cooperative control subsystem to obtain the cooperative current control command vector of the traction station, and calculate the voltage control command vector of the traction station according to the cooperative current control command vector, and coordinately control the flexible direct current traction power supply system based on the voltage control command vector.

[0039] According to one embodiment of the present invention, the objective function is:

[0040] ;

[0041] in, is the objective function, is the circulation suppression deviation, For the DC network coordinated control subsystem losses, is the converter loss, is the AC network loss, , , , are all weight coefficients.

[0042] According to an embodiment of the present invention, the circulation suppression deviation is:

[0043] ;

[0044] in, is the circulation suppression deviation, For external power supply lines that require circulating current suppression, For external power supply line, For the external power supply line in the collaborative control subsystem j The power, It is the external power supply line in the load natural distribution subsystem. j Power;

[0045] The DC network coordinated control subsystem loss is:

[0046] ;

[0047] in, For the DC network coordinated control subsystem losses, For traction, is the number of tractions, r ci For the traction in the cooperative control subsystem i and traction station i +1 catenary resistance between r ri For the traction in the cooperative control subsystem iand traction station i +1 rail resistance between is the traction network current vector of the cooperative subsystem;

[0048] The converter loss is:

[0049] ;

[0050] in, is the converter loss, is the coefficient, For traction in DC network i Power;

[0051] The AC network loss is:

[0052] ;

[0053] in, is the AC network loss, is the branch current vector of the AC network, is the branch resistance matrix of the AC network.

[0054] According to an embodiment of the present invention, the preset constraint condition includes a voltage constraint, a converter capacity constraint and a physical constraint of the decision variable itself, wherein the voltage constraint is:

[0055] U min ≤U si ≤U max ;

[0056] in, U min is the minimum value of the traction voltage, U si For traction i The voltage, U max is the maximum value of the traction voltage;

[0057] The converter capacity constraint is:

[0058] I min ≤ I si ≤ I max ;

[0059] in, I min is the minimum value of the traction current, I si For tractioni The current, I max is the maximum value of the traction current;

[0060] The physical constraints of the decision variables themselves are:

[0061] ;

[0062] in, For the i Coordinated current control instructions for each traction station.

[0063] According to the coordinated control device of the centralized external power supply flexible direct current traction power supply system of the embodiment of the present invention, an original system model including an AC network and a DC network is constructed, and the original system model is decomposed into a load natural distribution subsystem and a coordinated control subsystem; an objective function is constructed based on the circulating current suppression deviation, the DC network coordinated control subsystem loss, the converter loss and the AC network loss, and a quadratic programming model is established according to the objective function and preset constraints; the quadratic programming model is solved to obtain the coordinated current control instruction vector of the traction station, and the voltage control instruction vector of the traction station is calculated according to the coordinated current control instruction vector, and the flexible direct current traction power supply system is coordinatedly controlled based on the voltage control instruction vector. Thus, the contradiction between the low calculation efficiency and the insufficient optimization effect of the prior art is solved, and efficient coordinated control that quickly responds to load changes while ensuring system performance is achieved.

[0064] A third aspect of the present invention provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement a collaborative control method for a centralized external power supply flexible direct current traction power supply system as described in the above embodiment.

[0065] A fourth aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement a coordinated control method for a centralized external power supply flexible direct current traction power supply system as described in the above embodiment.

[0066] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0068] Figure 1 It is a flow chart of a coordinated control method of a centralized external power supply flexible direct current traction power supply system provided according to an embodiment of the present invention;

[0069] Figure 2 is a structural schematic diagram of a DC network of an original system according to an embodiment of the present invention;

[0070] Figure 3 A schematic diagram of the structure of an AC network of an original system according to an embodiment of the present invention;

[0071] Figure 4 A schematic diagram of the structure of an AC network of a load natural distribution subsystem according to an embodiment of the present invention;

[0072] Figure 5 A schematic diagram of the structure of a DC network of a load natural distribution subsystem according to an embodiment of the present invention;

[0073] Figure 6 A schematic diagram of the structure of an AC network of a cooperative control subsystem according to an embodiment of the present invention;

[0074] Figure 7 A schematic diagram of the structure of a DC network of a cooperative control subsystem according to an embodiment of the present invention;

[0075] Figure 8 It is a block diagram of a coordinated control device for a centralized external power supply flexible direct current traction power supply system according to an embodiment of the present invention;

[0076] Fig. 9 FIG. 4 is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0077] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0078] The following describes a collaborative control method and device for a centralized external power supply flexible DC traction power supply system according to an embodiment of the present invention with reference to the accompanying drawings. In response to the problems of insufficient optimization effect and long calculation time mentioned in the above background technology, the present invention provides a collaborative control method for a flexible DC traction power supply system that adopts a centralized external power supply while taking into account AC and DC networks to achieve operation optimization effects with high computational efficiency. It solves the contradiction between low computational efficiency and insufficient optimization effect of the prior art, and achieves efficient collaborative control that quickly responds to load changes while ensuring system performance.

[0079] Specifically, Figure 1A flowchart of a collaborative control method for a centralized external power supply flexible direct current traction power supply system provided in an embodiment of the present invention.

[0080] like Figure 1 As shown, the coordinated control method of the centralized external power supply flexible direct current traction power supply system includes the following steps:

[0081] In step S101, an original system model including an AC network and a DC network is constructed, and the original system model is decomposed into a load natural distribution subsystem and a coordinated control subsystem.

[0082] Specifically, the original system modeling is as follows Figure 2 and Figure 3 As shown. In the DC network, Figure 2 As shown, U si For traction i The voltage, I si For traction i The current, P si For traction i The power, I vk For locomotive k The AC network structure of the original system is relatively complex, such as Figure 3 As shown, in general, each traction has two AC busbars on the left and right, and each busbar is connected to a converter and a power lighting load through a transformer. Some lines only have one AC busbar connected to the converter. j The internal potential is relatively constant and is modeled as a voltage source, with the voltage and power being expressed as U uj , P uj The voltage source is connected to the medium voltage ring network through a transformer, and the medium voltage ring network is connected to the AC busbar of the traction station through various cables. P si The sum of the losses of the converter and the loss of the traction station is equal to the power on the AC side of the traction station. P sACi In general, each traction station is equipped with two AC buses on the left and right, and each bus is connected to a converter with the same capacity. In this case, the converter power of each bus is P sACi / 2, more generally, if the capacity of the converter connected to one of the buses accounts for a ratio of the converter capacity of the traction substation to α , then the converter power of the bus is αP sACi Assume that the voltage amplitude of the AC network is Uac The phase angle is 0, and the load of the traction station can be modeled as a current source. The current source corresponding to the power lighting load of the left bus is I auxi_1 , the current source corresponding to the power lighting load of the right bus is I auxi_2 , the power corresponding to the power lighting load of the left bus is P auxi_1 , the power corresponding to the power lighting load of the right bus is P auxi_2 , then I auxi_1 = P auxi_1 / U ac , I auxi_2 = P auxi_2 / U ac The current sources corresponding to the traction converters on the left and right buses are I sAC_1 , I sACi_2 The power corresponding to the traction converter of the left and right busbars is P sACi_1 , P sACi_2 Indicates that I sACi_1 = P sACi_1 / U ac , I sACi_2 = P sACi_2 / U ac Assume that the capacity of the converter connected to the left and right buses accounts for the proportion of the converter capacity of the traction station. α 1, α 2, then I sACi_1 = α 1 P sACi / U ac , I sACi_2 = α 2 P sACi / U ac .

[0083] Furthermore, according to the superposition principle of circuit theory, the original system can be divided into a natural load distribution subsystem and a cooperative control subsystem. Figure 4 and Figure 5 As shown in Figure 6 and Figure 7 As shown. Among them, the traction current of the load natural distribution subsystem is I si_nd , external power supply line in the load natural distribution subsystem j The power distribution is P uj_nd , the traction current in the coordinated control subsystem is I si_cc , external power supply line in the cooperative control subsystem j The power distribution is P uj_cc .

[0084] like Figure 4 and Figure 5 As shown in the figure, the load natural distribution subsystem retains the following excitation sources: locomotive current source in the DC network, power lighting load current source in the AC network, voltage source of external power supply line in the AC network, converter current source of the left busbar of the traction station in the AC network I sACi_1nd and the converter current source of the right bus I sACi_2nd ,in, I sACi_1nd = α 1 U si I si_nd / U ac , I sACi_2nd = α 2 U si I si_nd / U ac .

[0085] like Figure 6 and Figure 7 As shown in the figure, the coordinated control subsystem retains the following excitation sources: the voltage source of the traction station in the DC network, the converter current source of the left bus of the traction station in the AC network I sACi_1cc and the converter current source of the right busbar of the traction station I sACi_2cc ,in, I sACi_1cc = α 1U si I si_cc / U ac , I sACi_2cc = α 2 U si I si_cc / U ac . Figure 7 middle, r ci Represents the traction in the cooperative control subsystem i and traction station i +1 catenary resistance between r ri Represents the traction in the cooperative control subsystem i and traction station i +1 rail resistance between.

[0086] Further, using U s * represents the voltage control command vector of the traction station, where U s * =[ U s1 * , U s2 * , …, U si * , …, U sN * ] T , U si * For the i The voltage control command of a traction station, N is the number of tractions. Solve for the variable U s * It is a collaborative control task. The traditional optimization method of flexible direct current traction power supply system needs to solve a nonlinear non-convex optimization problem, which has a slow solution speed. The quadratic programming problem is the simplest nonlinear optimization problem with the most mature algorithm and high solution efficiency. Therefore, the present invention adopts the form of quadratic programming to solve the approximate optimal solution of power flow optimization, thereby improving the solution efficiency of the overall algorithm. The voltage control instruction algorithm based on quadratic programming is introduced below:

[0087] The decision variable of the embodiment of the present invention can be selected as the voltage control instruction vector of the traction station. U s * Or another set of variables equivalent to it, namely the coordinated current control command vector I s_cc * ,in, I s_cc * =[ I s1_cc * , I s2_cc * , …, I si_cc * , …, I sN_cc * ] T , I si_cc * Indicates i It should be noted that the voltage control instruction vector of the traction station is U s * Coordinated current control command vector I s_cc * Can be converted into each other.

[0088] Furthermore, the traction voltage can be decomposed into common mode component and differential mode component:

[0089] ;

[0090] in, U s is the traction voltage, U s_cm is the common mode component vector of the traction voltage, U s_dm is the differential mode component vector of the traction voltage, U s_cm =[ U s_cm ,… U s_cm ,… U s_cm ] T , U s_dm =[ U s1_dm , U s2_dm ,… U si_dm,… U sN_dm ] T ; U s =[ U s1 , U s2 , …, U si , …, U sN ] T .

[0091] Furthermore, the branch voltage vector is defined as U b_cc =[ U b1_cc , U b2_cc ,… U bi_cc ,… U b(N-1)_cc ] T . Based on Kirchhoff's voltage law:

[0092]

[0093] Define the conductivity matrix G :

[0094]

[0095] Based on Ohm's law:

[0096]

[0097] Among them, the traction network current vector of the cooperative subsystem is defined as I c_cc =[ I c1_cc , I c2_cc ,… I ci_cc ,… I c(N-1)_cc ] T , based on Kirchhoff’s current law:

[0098]

[0099] Conversely, based on Kirchhoff's current law,

[0100]

[0101]

[0102] Defining the resistor matrixR :

[0103]

[0104] Branch voltage vector U b_cc :

[0105]

[0106] Furthermore, the differential mode voltage vector U s_dm , U s_dm =[ U s1_dm , U s2_dm ,… U si_dm ,… U s(N-1)_dm ] T , we can determine:

[0107]

[0108] It is understandable that the common mode voltage of the traction station can be set arbitrarily, but it is necessary to ensure that the system voltage meets the operation requirements. In order to reduce the system network loss as much as possible, it is generally selected to make the maximum traction station voltage reach the maximum value of the operation constraint.

[0109] Finally, the traction voltage U s It can be calculated as follows:

[0110]

[0111] It should be noted that the superscript * The mathematical relationship between the reference values ​​is consistent with the mathematical relationship between the physical quantities to which they correspond. U s * and I s_cc * They can also be converted to each other based on the above formula.

[0112] It should be noted that the selection U s * or I s_cc * As decision variables, there is no essential difference in modeling the quadratic programming problem. The application embodiment can be used I s_cc *as decision variables for detailed modeling.

[0113] In step S102, an objective function is constructed based on circulating current suppression deviation, DC network cooperative control subsystem loss, converter loss and AC network loss, and a quadratic programming model is established according to the objective function and preset constraints.

[0114] Specifically, the objective function of the embodiment of the present invention is used to achieve the reduction of operating costs and meet the needs of energy conservation and carbon reduction. The objective function consists of four items: circulating current suppression deviation, DC network collaborative control subsystem loss, converter loss, and AC network loss. The preset constraints take into account voltage constraints, converter capacity constraints, and physical constraints of the decision variables themselves. The number of decision variables in the objective function of this optimization model is higher than 2, and the number of decision variables of the constraints is higher than 1, so further simplification is required: considering that the traction station voltage between adjacent time steps will not change suddenly, it is assumed that the traction station voltage is not a variable but a constant, where the constant is taken as the traction station voltage value of the previous step. After adopting this assumption, a quadratic programming model can be established:

[0115] The objective function is:

[0116] ;

[0117] in, is the objective function, is the circulation suppression deviation, For the DC network coordinated control subsystem losses, is the converter loss, is the AC network loss, , , , They are all weight coefficients and can be set to 1 or flexibly adjusted according to importance, and are not specifically limited here.

[0118] Furthermore, the calculation of the objective function circulating current suppression deviation needs to consider which incoming lines need circulating current suppression. The definition of circulating current is the power sign of the external power incoming line. First, it is necessary to calculate the external power incoming line in the load natural distribution subsystem. j Power P uj_nd External power supply line in the coordinated control subsystem j Power P uj_cc Among them, the external power supply line in the collaborative control subsystem j Power P uj_cc for:

[0119]

[0120] in, H uj1 For external power supply j The traction station number set of the left busbar of the connected traction station, H uj2 For external power supply j The set of traction depot numbers of the right busbar of the connected traction depot.

[0121] Furthermore, the external power supply line in the load natural distribution subsystem j Power P uj_nd for:

[0122] P uj_nd = P uj -P uj_cc

[0123] in, P uj_nd Indicates that there is no coordinated control and the load is naturally distributed. j If the total power of all power lines is positive, and the external power lines in the load natural distribution subsystem j Power P uj_nd Negative, indicating that the external power supply line j When there is no coordinated control, there will be a circulating current, and the external power supply line j Circulation suppression is required; similarly, if the total power of all power lines is negative, and the external power lines in the load natural distribution subsystem j Power P uj_nd If positive, it means external power supply is input j When there is no coordinated control, there will be a circulating current, and the external power supply line j Circulation suppression is required. H circulation In order to suppress the circulation, the set H circulation The power supply line power in the circuit is as close to 0 as possible to prevent the power supply line power from having different signs. To this end, the quadratic type of circulating current suppression deviation expression is designed as:

[0124]

[0125] The above expression shows the deviation of circulating current suppression. In the case of perfect suppression, P circulation is 0. Among them, is the circulation suppression deviation, For external power supply lines that require circulating current suppression, For external power supply line, For external power supply in the collaborative control subsystem j The power, It is the external power supply line in the load natural distribution subsystem. j of power.

[0126] Furthermore, the loss of the DC network cooperative control subsystem is:

[0127] ;

[0128] in, For the DC network coordinated control subsystem losses, For traction, is the number of tractions, r ci For the traction in the cooperative control subsystem i and traction station i +1 catenary resistance between r ri For the traction in the cooperative control subsystem i and traction station i +1 rail resistance between is the traction network current vector of the cooperative subsystem;

[0129] The converter loss is:

[0130] ;

[0131] in, is the converter loss, is the coefficient used to convert the square of DC power to loss; For traction in DC network i of power.

[0132] Furthermore, the calculation of the AC network loss in the objective function is based on the circuit calculation, and there are many calculation methods. For example, the embodiment of the present invention can establish a road-branch association matrix for the AC network. T The branch current vector of the AC network is assumed to be I b , the node injection current vector of the AC network is I N , then according to the definition of the road-branch association matrix, we have I b = T T I N , assuming the branch resistance matrix of the AC network is R AC, then the AC network loss is:

[0133] ;

[0134] in, is the AC network loss, is the branch current vector of the AC network, is the branch resistance matrix of the AC network.

[0135] Furthermore, in some embodiments, the preset constraint conditions include voltage constraint, converter capacity constraint and physical constraint of the decision variable itself, wherein the voltage constraint is:

[0136] U min ≤U si ≤U max ;

[0137] in, U min is the minimum value of the traction voltage, U si For traction i The voltage, U max is the maximum value of the traction voltage;

[0138] The converter capacity constraint is:

[0139] I min ≤ I si ≤ I max ;

[0140] in, I min is the minimum value of the traction current, I si For traction i The current, I max is the maximum value of the traction current. I max Use capacity size P lim Divide the traction voltage by the above step length to get, I min Use capacity size P lim Divide the traction voltage by the above step length and then multiply by (-1) to get.

[0141] Furthermore, the physical constraints on the decision variables themselves are based on Kirchhoff's current law:

[0142] ;

[0143] in, For the i Coordinated current control instructions for each traction station.

[0144] In step S103, based on the load natural distribution subsystem and the cooperative control subsystem, the quadratic programming model is solved to obtain the cooperative current control command vector of the traction subsystem, and the voltage control command vector of the traction subsystem is calculated based on the cooperative current control command vector, and the flexible DC traction power supply system is cooperatively controlled based on the voltage control command vector.

[0145] Specifically, after the quadratic programming model is solved, the coordinated current control command vector can be obtained. I s_cc * , based on the cooperative current control command vector I s_cc * The final voltage control command vector can be calculated U s * It is sent to each traction station as a control instruction, and the flexible DC traction power supply system is coordinated and controlled based on the voltage control instruction.

[0146] Therefore, the collaborative control method of the centralized external power supply flexible direct current traction power supply system proposed in the present invention can be used to optimize collaborative control on the one hand, and can also be applied to other optimization problems. The present invention takes into account both the AC network and the DC network, and is therefore suitable for a flexible direct current traction power supply system using a centralized external power supply. As long as it is necessary to consider the optimization problem of the AC network and the DC network traction power supply system at the same time, the idea of ​​the present invention can be used to accelerate the optimization solution. For example, for a steady-state power flow analysis problem based on the optimal power flow, the power flow calculation can be calculated first, and then it is assumed that the traction station voltage is the result of the traction station voltage in the previous iteration, and the result of the power flow calculation is input into the quadratic programming algorithm proposed in the present invention, which can achieve fast optimal solution calculation.

[0147] According to the coordinated control method of the centralized external power supply flexible direct current traction power supply system of the embodiment of the present invention, the objective function is constructed based on the circulating current suppression deviation, the loss of the DC network coordinated control subsystem, the converter loss and the AC network loss, and a quadratic programming model is established according to the objective function and the preset constraints; the quadratic programming model is solved to obtain the coordinated current control instruction vector of the traction station, and the voltage control instruction vector of the traction station is calculated according to the coordinated current control instruction vector, and the flexible direct current traction power supply system is coordinated controlled based on the voltage control instruction vector. As a result, the contradiction between the low calculation efficiency and the insufficient optimization effect of the prior art is solved, and the calculation efficiency of the optimization calculation in the coordinated control of the flexible direct current traction power supply system using a centralized external power supply is improved, so that the update rate of the control instruction of the operation optimization technology can keep up with the rate of load change, meeting the requirements of engineering practicality.

[0148] Next, the coordinated control device of the centralized external power supply flexible direct current traction power supply system proposed in accordance with an embodiment of the present invention is described with reference to the accompanying drawings.

[0149] Figure 8 It is a block diagram of a collaborative control device for a centralized external power supply flexible direct current traction power supply system according to an embodiment of the present invention.

[0150] like Figure 8 As shown, the collaborative control device 10 of the centralized external power supply flexible DC traction power supply system includes: an original system model building module 100, a secondary programming model building module 200 and a control module 300.

[0151] Among them, the original system model construction module 100 is used to construct the original system model including the AC network and the DC network, and decompose the original system model into a load natural distribution subsystem and a collaborative control subsystem; the secondary programming model construction module 200 is used to construct the objective function based on the circulating current suppression deviation, the DC network collaborative control subsystem loss, the converter loss and the AC network loss, and establish the secondary programming model according to the objective function and preset constraints; the control module 300 is used to solve the secondary programming model based on the load natural distribution subsystem and the collaborative control subsystem, obtain the collaborative current control command vector of the traction station, and calculate the voltage control command vector of the traction station according to the collaborative current control command vector, and perform collaborative control of the flexible DC traction power supply system based on the voltage control command vector.

[0152] Furthermore, in some embodiments, the objective function is:

[0153] ;

[0154] in, is the objective function, is the circulation suppression deviation, For the DC network coordinated control subsystem losses, is the converter loss, is the AC network loss, , , , are all weight coefficients.

[0155] Further, in some embodiments, the circulation suppression deviation is:

[0156] ;

[0157] in, is the circulation suppression deviation, For external power supply lines that require circulating current suppression, For external power supply line, For external power supply in the collaborative control subsystem j The power, It is the external power supply line in the load natural distribution subsystem. j Power;

[0158] The loss of DC network coordinated control subsystem is:

[0159] ;

[0160] in, For the DC network coordinated control subsystem losses, For traction, is the number of tractions, r ci For the traction in the cooperative control subsystem i and traction station i +1 catenary resistance between r ri For the traction in the cooperative control subsystem i and traction station i +1 rail resistance between is the traction network current vector of the cooperative subsystem;

[0161] The converter loss is:

[0162] ;

[0163] in, is the converter loss, is the coefficient, For traction in DC network i Power;

[0164] The AC network loss is:

[0165] ;

[0166] in, is the AC network loss, is the branch current vector of the AC network, is the branch resistance matrix of the AC network.

[0167] Furthermore, in some embodiments, the preset constraint conditions include voltage constraint, converter capacity constraint and physical constraint of the decision variable itself, wherein the voltage constraint is:

[0168] U min ≤U si ≤U max ;

[0169] in, U min is the minimum value of the traction voltage, U si For traction i The voltage, U max is the maximum value of the traction voltage;

[0170] The converter capacity constraint is:

[0171] I min ≤ I si ≤ I max ;

[0172] in, I min is the minimum value of the traction current, I si For traction i The current, I max is the maximum value of the traction current;

[0173] The physical constraints on the decision variables themselves are:

[0174] ;

[0175] in, For the i Coordinated current control instructions for each traction station.

[0176] It should be noted that the above explanation of the embodiment of the coordinated control method of the centralized external power supply flexible DC traction power supply system is also applicable to the coordinated control device of the centralized external power supply flexible DC traction power supply system of this embodiment, and will not be repeated here.

[0177] According to the coordinated control device of the centralized external power supply flexible direct current traction power supply system of the embodiment of the present invention, an original system model including an AC network and a DC network is constructed, and the original system model is decomposed into a load natural distribution subsystem and a coordinated control subsystem; an objective function is constructed based on the circulating current suppression deviation, the DC network coordinated control subsystem loss, the converter loss and the AC network loss, and a quadratic programming model is established according to the objective function and preset constraints; the quadratic programming model is solved to obtain the coordinated current control instruction vector of the traction station, and the voltage control instruction vector of the traction station is calculated according to the coordinated current control instruction vector, and the flexible direct current traction power supply system is coordinatedly controlled based on the voltage control instruction vector. Thus, the contradiction between the low calculation efficiency and the insufficient optimization effect of the prior art is solved, and efficient coordinated control that quickly responds to load changes while ensuring system performance is achieved.

[0178] Fig. 9 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. The electronic device may include:

[0179] A memory 901 , a processor 902 , and a computer program stored in the memory 901 and executable on the processor 902 .

[0180] When the processor 902 executes the program, the coordinated control method of the centralized external power supply flexible direct current traction power supply system provided in the above embodiment is implemented.

[0181] Furthermore, the electronic device further comprises:

[0182] The communication interface 903 is used for communication between the memory 901 and the processor 902 .

[0183] The memory 901 is used to store computer programs that can be executed on the processor 902 .

[0184] The memory 901 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0185] If the memory 901, the processor 902 and the communication interface 903 are implemented independently, the communication interface 903, the memory 901 and the processor 902 can be connected to each other through a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Fig. 9 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0186] Optionally, in a specific implementation, if the memory 901, the processor 902 and the communication interface 903 are integrated on a chip, the memory 901, the processor 902 and the communication interface 903 can communicate with each other through an internal interface.

[0187] The processor 902 may be a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present invention.

[0188] An embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned coordinated control method of the centralized external power supply flexible direct current traction power supply system.

[0189] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means 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 specific features, structures, materials or characteristics described may be combined in any one or N 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.

[0190] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0191] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A coordinated control method for a centralized external power supply flexible direct current traction power supply system, characterized in that: The following steps are involved: Constructing an original system model including an AC network and a DC network, and decomposing the original system model into a load natural distribution subsystem and a coordinated control subsystem; Constructing an objective function based on circulating current suppression deviation, DC network coordinated control subsystem loss, converter loss and AC network loss, and establishing a quadratic programming model according to the objective function and preset constraints; Based on the load natural distribution subsystem and the coordinated control subsystem, the quadratic programming model is solved to obtain the coordinated current control command vector of the traction station, and the voltage control command vector of the traction station is calculated according to the coordinated current control command vector, and the flexible direct current traction power supply system is coordinated controlled based on the voltage control command vector; Wherein, the objective function is: ； in, is the objective function, is the circulation suppression deviation, The DC network coordinated control subsystem losses, is the converter loss, is the AC network loss, , , , All are weight coefficients; The circulation suppression deviation is: ； in, is the circulation suppression deviation, For external power supply lines that require circulating current suppression, For external power supply line, For the external power supply line in the collaborative control subsystem j The power, It is the external power supply line in the load natural distribution subsystem. j of power.

2. The coordinated control method of a centralized external power supply flexible direct current traction power supply system according to claim 1 is characterized in that: The DC network coordinated control subsystem loss is: ； in, The DC network coordinated control subsystem losses, For traction, is the number of tractions, r ci For the traction in the cooperative control subsystem i and traction station i +1 catenary resistance between r ri For the traction in the cooperative control subsystem i and traction station i +1 rail resistance between is the traction network current vector of the cooperative subsystem; The converter loss is: ； in, is the converter loss, is the coefficient, For traction in DC network i Power; The AC network loss is: ； in, is the AC network loss, is the branch current vector of the AC network, is the branch resistance matrix of the AC network.

3. The coordinated control method of a centralized external power supply flexible DC traction power supply system according to claim 1 is characterized in that: The preset constraints include voltage constraints, converter capacity constraints and physical constraints of the decision variables themselves, wherein the voltage constraints are: U min ≤U si ≤U max ； in, U min is the minimum value of the traction voltage, U si For traction i The voltage, U max is the maximum value of the traction voltage; The converter capacity constraint is: I min ≤ I si ≤ I max ； in, I min is the minimum value of the traction current, I si For traction i The current, I max is the maximum value of the traction current; The physical constraints of the decision variables themselves are: ； in, For the i Coordinated current control instructions for each traction station.

4. A coordinated control device for a centralized external power supply flexible direct current traction power supply system, characterized in that: include: An original system model building module is used to build an original system model including an AC network and a DC network, and decompose the original system model into a load natural distribution subsystem and a coordinated control subsystem; A quadratic programming model building module, used to build an objective function based on circulating current suppression deviation, DC network collaborative control subsystem loss, converter loss and AC network loss, and establish a quadratic programming model according to the objective function and preset constraints; A control module, configured to solve the quadratic programming model based on the load natural distribution subsystem and the coordinated control subsystem to obtain a coordinated current control command vector of the traction station, calculate a voltage control command vector of the traction station according to the coordinated current control command vector, and coordinately control the flexible direct current traction power supply system based on the voltage control command vector; Wherein, the objective function is: ； in, is the objective function, is the circulation suppression deviation, The DC network coordinated control subsystem losses, is the converter loss, is the AC network loss, , , , All are weight coefficients; The circulation suppression deviation is: ； in, is the circulation suppression deviation, For external power supply lines that require circulating current suppression, For external power supply line, For the external power supply line in the collaborative control subsystem j The power, It is the external power supply line in the load natural distribution subsystem. j of power.

5. The coordinated control device of the centralized external power supply flexible direct current traction power supply system according to claim 4 is characterized in that: The DC network coordinated control subsystem loss is: ； in, For the DC network coordinated control subsystem losses, For traction, is the number of tractions, r ci Represents the traction in the cooperative control subsystem i and traction station i +1 catenary resistance between r ri Represents the traction in the cooperative control subsystem i and traction station i +1 rail resistance between is the traction network current vector of the cooperative subsystem; The converter loss is: ； in, is the converter loss, is the coefficient, For traction in DC network i Power; The AC network loss is: ； in, is the AC network loss, is the branch current vector of the AC network, is the branch resistance matrix of the AC network.

6. The coordinated control device of the centralized external power supply flexible direct current traction power supply system according to claim 4 is characterized in that: The preset constraints include voltage constraints, converter capacity constraints and physical constraints of the decision variables themselves, wherein the voltage constraints are: U min ≤U si ≤U max ； in, U min is the minimum value of the traction voltage, U si For traction i The voltage, U max is the maximum value of the traction voltage; The converter capacity constraint is: I min ≤ I si ≤ I max ； in, I min is the minimum value of the traction current, I si For traction i The current, I max is the maximum value of the traction current; The physical constraints of the decision variables themselves are: ； in, For the i Coordinated current control instructions for each traction station.

7. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the collaborative control method of a centralized external power supply flexible direct current traction power supply system as described in any one of claims 1 to 3.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement a coordinated control method for a centralized external power supply flexible direct current traction power supply system as described in any one of claims 1 to 3.

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