A parameter optimization design method for a compensation device for an electrified railway

Abstract

The application discloses a kind of electric railway in-phase compensation device parameter optimization design method, it is related to electric railway resonance analysis field.Set in-phase compensation device each part parameter range;Set the change range of harmonic number [h1, h2];Form the system node admittance matrix of each part parameter variation under harmonic number h1;Obtain the eigenvalue of system node admittance matrix corresponding to different parameters;Set operation step;Maximum eigenvalue corresponding resonance characteristic is obtained under different parameters;Make system resonance characteristic curve;Set the characteristic harmonic frequency band of locomotive and in-phase compensation device;Set in-phase compensation device optimization target;Initialize particle swarm parameter and randomly initialize the position, speed of each parameter particle of in-phase compensation device;Calculate the objective function value of each parameter particle in in-phase compensation device;According to objective function value, update the value of in-phase compensation device parameter particle;Judge whether iteration can end;Output optimal solution and make corresponding system resonance curve.

Description

Technical Field

[0001] This invention relates to the field of resonance characteristic analysis technology for electrified railways, and in particular to a method for optimizing the design of parameters of in-phase compensation devices for electrified railways. Background Technology

[0002] Currently, my country's electrified railways adopt a single-sided power supply method, resulting in electrical phase separation between the traction substation outlet and the section substation. This phase separation causes power loss when trains pass through, increases train travel time, and generates a series of power quality problems that reduce power supply reliability. With the rapid development of my country's electrified railways and urban rail transit, scholars at home and abroad have proposed adding in-phase compensation devices to achieve through-phase power supply to solve the problems of electrical phase separation and power quality issues dominated by negative sequence.

[0003] With the addition of in-phase compensation devices, the locomotive and the power electronic equipment in these devices will generate a large amount of harmonic current. If this harmonic current matches the resonant point of the railway system, it will cause resonant overvoltage, which in severe cases will directly damage the equipment and cause system collapse. Current research on system resonant characteristics has proposed methods such as frequency domain analysis and modal analysis, effectively revealing the system's resonant point. Active and passive filtering methods are used to prevent the harmonic current generated by the power electronic equipment from matching the system's resonant point. However, existing research focuses on traditional single-sided power supply methods and has not studied systems with in-phase compensation devices. The design of in-phase compensation device parameters is limited to meeting the control effect of the compensation current, and the additional filter also incurs high costs.

[0004] Therefore, it is necessary to study the system resonance characteristics of the in-phase compensation device and the parameter design method of the in-phase compensation device. Summary of the Invention

[0005] The purpose of this invention is to provide a parameter optimization design method for in-phase compensation devices in electrified railways. This method can not only reveal the resonance characteristics of the railway system, but also provide the optimal solution for the parameters of the in-phase compensation device through an optimization algorithm, thereby avoiding resonance from the source and solving the problem of high cost caused by setting up filters.

[0006] The objective of this invention is achieved through the following technical solution: a method for optimizing the design parameters of a phase compensation device for electrified railways, specifically:

[0007] (1) Based on the factors affecting the resonance point of the electrified railway power supply system, a model of the railway power supply system is established and the model parameters are initialized;

[0008] (2) Based on the control effect of the power electronic equipment in the in-phase compensation device and the premise of normal power supply to the locomotive, set the range of electrical quantity parameters of the components in the in-phase compensation device and the control parameters of the controller.

[0009] (3) Set the range of harmonic order variation of the power supply system [h1, h2], where h1 is the minimum value of the harmonic order variation range and h2 is the maximum value of the harmonic order variation range;

[0010] (4) When the harmonic order of the power supply system changes to the minimum value, the inductance value and capacitance value of the in-phase compensation device and the control parameters of the controller are used to form the system node admittance matrix when it changes from low to high within the set range.

[0011] (5) The eigenvalues ​​of the system node admittance matrix corresponding to different parameters are obtained by calculation;

[0012] (6) Based on h1=h1+Δh, where Δh is the operation step size, the computer determines whether h1 is less than or equal to h2. If so, return to step (4).

[0013] (7) The harmonic order and impedance amplitude of the resonant point corresponding to the maximum eigenvalue under different parameters are obtained by calculation;

[0014] (8) Using the harmonic order and impedance amplitude, plot the resonance characteristic curve for each parameter;

[0015] (9) By measuring the actual harmonic voltage and harmonic current on site, the characteristic harmonic frequency band of the locomotive and the in-phase compensation device is set.

[0016] (10) The optimal solution of the parameters of each component in the in-phase compensation device is obtained by using the particle swarm optimization algorithm to set the optimization target of the in-phase compensation device.

[0017] (11) Initialize the particle swarm parameters and randomly initialize the position and velocity of each particle in the in-phase compensation device;

[0018] (12) Calculate the objective function value of each particle in each parameter of the in-phase compensation device;

[0019] (13) Update the value of each parameter particle of the in-phase compensation device according to the objective function value;

[0020] (14) The computer determines whether the error of the optimal solution for each parameter is less than the given limit or whether the number of iterations is satisfied. If not, return to step (12).

[0021] (15) Output the optimal solution and plot the resonance curve of the in-phase compensation device corresponding to the optimal solution of each parameter.

[0022] The modeling of the railway power supply system includes establishing models of in-phase compensation devices, transmission lines, locomotives, and transformers. The in-phase compensation device modeling needs to consider the influencing factors such as the dead time of the power electronic converter, switching time, harmonic distribution, and control strategy. The transmission line modeling needs to consider the standing wave effect. The locomotive model needs to consider the locomotive load, equivalent impedance, and harmonic distribution. The transformer model needs to consider hysteresis loss and eddy current loss.

[0023] The range of electrical parameters of the components and control parameters of the controller in the in-phase compensation device includes the range of values ​​for inductor A [L]. A1 L A2 ], L A1 L is the minimum value in the range of inductance A. A2 The maximum value within the range of inductor A; the range of inductor B is [L]. B1 L B2 ], L B1 L is the minimum value in the range of inductance B. B2 The maximum value of inductor B is defined as the maximum value within its range; the capacitance range is defined as [C1, C2], where C1 is the minimum value within its range and C2 is the maximum value within its range; the proportional and integral parameter ranges of the proportional-integral controller are set, with the proportional parameter range [K]. P1 K P2 ], K P1 K is the minimum value in the range of the proportional parameter. P2 The maximum value within the range of the proportional parameter; the range of the integral parameter [K] I1 K I2 ], K I1 K is the minimum value in the range of the integration parameter. I2 This represents the maximum value within the range of values ​​for the integration parameter.

[0024] The system node admittance matrix is ​​a square matrix of the following form:

[0025]

[0026] In the node admittance matrix, the subscripts of all elements represent the node numbers of the system, Y 11 Y represents the self-admittance of the first node of the system. 22 Y represents the self-admittance of the second node in the system. nn Y represents the self-admittance of the nth node in the system. 12 Y 21 Y represents the mutual admittance between the first node and the second node. 1n Y n1 Y represents the mutual admittance between the 1st node and the nth node.2n Y n2 This represents the mutual admittance between the second node and the nth node.

[0027] The optimization objective of the in-phase compensation device is to avoid the characteristic harmonic frequency band of the locomotive by using the resonant point of the power supply system, and to obtain the in-phase compensation device with the lowest cost under the premise of meeting the compensation requirements, providing normal power supply to the locomotive and achieving good waveform control effect.

[0028] The initialized particle swarm parameters include the particle swarm size N, the particle dimension (i.e., the number of in-phase compensation device parameters D), the total number of iterations M, the inertia weight ω, and the learning factors c1 and c2; the random initialization of the particle position and velocity includes randomly initializing the position X of the i-th particle. id The velocity V of the i-th particle id The optimal position P of the i-th particle id Optimal position P of the group d d = 1, 2, ..., D; i = 1, 2, ..., N, where position represents the value of each component parameter and speed represents the change in parameter value.

[0029] The calculation of the objective function values ​​of particles in each parameter of the in-phase compensation device includes the optimal objective f of the i-th particle. id and the group optimal objective f d d = 1, 2, ..., D; i = 1, 2, ..., N, that is, whether the harmonic order of the system resonance point deviates from the characteristic harmonic frequency band [T1, T2] of the locomotive and the in-phase compensation device, where T1 represents the minimum harmonic order of the characteristic harmonic frequency band and T2 represents the maximum harmonic order of the characteristic harmonic frequency band.

[0030] The updated in-phase compensation device takes values ​​for each parameter particle, including updating the velocity and position of each parameter particle, wherein the velocity update formula is: The position update formula is d = 1, 2, ..., D; i = 1, 2, ..., N; the m in the upper right corner of each symbol represents the value of the m-th iteration, m ≤ M, rand1(), rand2() represent random numbers in the interval [0, 1].

[0031] The judgment formula for the given limit is: ε is less than or equal to 10 -2 of decimals.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] I. This invention can reveal the resonant characteristics of a power supply system. It should be noted that this invention is not only applicable to electrified railways, but also to power systems, microgrids, etc.

[0034] Second, the present invention can change the controller parameters according to the system state (changes in locomotive model, changes in power supply operation mode, etc.) to avoid low-order resonance in the system.

[0035] Third, this invention can realize the design of parameters of each part of the in-phase compensation device. Under the premise of meeting the compensation requirements, providing normal power supply to the locomotive and achieving good waveform control, it can not only avoid resonance of the system, but also minimize the design cost of the in-phase compensation device.

[0036] Fourth, this invention can avoid resonance from the source without increasing costs by redesigning the filtering scheme.

[0037] In summary, those skilled in the art should understand that the steps of the present invention described above can be implemented using any computing device. The computing device can be nested within the measurement and control system of the in-phase compensation device and implemented using program code executable by the computing device. In some cases, the order of the above steps can be changed or a portion can be used as needed. Therefore, the present invention is not limited by any hardware or software. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the parameter optimization design method for the electrified railway phase compensation device described in Embodiment 1 of the present invention. Detailed Implementation

[0039] To better understand the inventive concept of this invention, its working principle is briefly described below: The goal is to obtain the lowest-cost in-phase compensation device while ensuring that the power supply system's resonant point avoids the locomotive's characteristic harmonic frequency band, meets compensation requirements, provides normal power supply to the locomotive, and achieves good waveform control. The proposed particle swarm optimization algorithm reveals the resonant characteristics of the railway system and provides the optimal solution for the in-phase compensation device parameters, thus avoiding resonance at its source and solving the problem of high costs associated with setting up filters. The invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0040] Example 1 Figure 1 As shown:

[0041] A method for optimizing the parameters of a phase compensation device for electrified railways includes the following steps:

[0042] (1) Based on the factors affecting the resonance point of the electrified railway power supply system, a model of the railway power supply system is established and the model parameters are initialized. The model includes the establishment of a model of the in-phase compensation device, a transmission line model, a locomotive model, and a transformer model. The influencing factors to be considered in the modeling of the in-phase compensation device are the dead time, switching time, harmonic distribution, and control strategy of the power electronic converter; the influencing factor to be considered in the modeling of the transmission line is the standing wave effect; the locomotive model needs to consider the locomotive load, equivalent impedance, and harmonic distribution; and the transformer model needs to consider hysteresis loss and eddy current loss.

[0043] (2) Based on the control effect of the power electronic equipment in the in-phase compensation device and the premise of normal power supply to the locomotive, the range of electrical quantity parameters of the components in the in-phase compensation device and the range of control parameters of the controller are set, including the value range of inductor A [L]. A1 L A2 ], L A1 L is the minimum value in the range of inductance A. A2 The maximum value within the range of inductor A; the range of inductor B is [L]. B1 L B2 ], L B1 L is the minimum value in the range of inductance B. B2 The maximum value of inductor B is defined as the maximum value within its range; the capacitance range is defined as [C1, C2], where C1 is the minimum value within its range and C2 is the maximum value within its range; the proportional and integral parameter ranges of the proportional-integral controller are set, with the proportional parameter range [K]. P1 K P2 ], K P1 K is the minimum value in the range of the proportional parameter. P2 The maximum value within the range of the proportional parameter; the range of the integral parameter [K] I1 K I2 ], K I1 K is the minimum value in the range of the integration parameter. I2 The maximum value within the range of values ​​for the integration parameter;

[0044] (3) Set the range of harmonic order variation of the power supply system [h1, h2], where h1 is the minimum value of the harmonic order variation range and h2 is the maximum value of the harmonic order variation range;

[0045] (4) When the harmonic order variation range of the power supply system is at its minimum, the inductance and capacitance values ​​of the in-phase compensation device and the control parameters of the controller are used to form the following system node admittance matrix, which varies from low to high within the set range:

[0046]

[0047] In the node admittance matrix, the subscripts of all elements represent the node numbers of the system, Y 11 Y represents the self-admittance of the first node of the system. 22 Y represents the self-admittance of the second node in the system. nn Y represents the self-admittance of the nth node in the system. 12 Y 21 Y represents the mutual admittance between the first node and the second node. 1n Y n1 Y represents the mutual admittance between the 1st node and the nth node. 2n Y n2 This represents the mutual admittance between the second node and the nth node;

[0048] (5) The eigenvalues ​​of the system node admittance matrix corresponding to different parameters are obtained by calculation;

[0049] (6) Based on h1=h1+Δh, where Δh is the operation step size, the computer determines whether h1 is less than or equal to h2. If so, return to step (4).

[0050] (7) The harmonic order and impedance amplitude of the resonant point corresponding to the maximum eigenvalue under different parameters are obtained by calculation;

[0051] (8) Using the harmonic order and impedance amplitude, plot the resonance characteristic curve for each parameter;

[0052] (9) By measuring the actual harmonic voltage and harmonic current on site, the characteristic harmonic frequency band of the locomotive and the in-phase compensation device is set.

[0053] (10) The particle swarm optimization algorithm is used to obtain the optimal solution of the parameters of each component in the in-phase compensation device so as to set the in-phase compensation device to avoid the characteristic harmonic frequency band of the locomotive at the resonant point of the power supply system. Under the premise of meeting the compensation requirements, providing normal power supply to the locomotive and achieving good waveform control effect, the optimization target of the in-phase compensation device with the lowest cost is obtained.

[0054] (11) Initialize the particle swarm parameters and randomly initialize the position and velocity of each particle in the in-phase compensation device. The particle swarm parameters include the particle swarm size N, the particle dimension (i.e., the number of parameters in the in-phase compensation device) D, the total number of iterations M, the inertia weight ω, and the learning factors c1 and c2. The position and velocity of the particles include the position X of the i-th particle. id The velocity V of the i-th particle id The optimal position P of the i-th particle id Optimal position P of the group d d = 1, 2, ..., D; i = 1, 2, ..., N, where position represents the value of each component parameter, and speed represents the change in the parameter value.

[0055] (12) Calculate the objective function value of each parameter particle in the in-phase compensation device, including the optimal objective f of the i-th particle. id and the group optimal objective f d d = 1, 2, ..., D; i = 1, 2, ..., N, that is, whether the harmonic order of the system's resonant point deviates from the characteristic harmonic frequency band [T1, T2] of the locomotive and the in-phase compensation device, where T1 represents the minimum harmonic order of the characteristic harmonic frequency band, and T2 represents the maximum harmonic order of the characteristic harmonic frequency band.

[0056] (13) Update the values ​​of each parameter particle in the in-phase compensation device according to the objective function value, including updating the velocity and position of each parameter particle, wherein the velocity update formula is: The position update formula is d = 1, 2, ..., D; i = 1, 2, ..., N; the superscript m of each symbol represents the value of the m-th iteration, m ≤ M; rand1(), rand2() represent random numbers in the interval [0, 1].

[0057] (14) The computer determines whether the error of the optimal solution for each parameter is less than a given limit or whether the number of iterations is satisfied. The given limit is determined by the following formula: ε is less than or equal to 10 -2 If the decimal is not found, return to step (12);

[0058] (15) Output the optimal solution and plot the resonance curve of the in-phase compensation device corresponding to the optimal solution of each parameter.

[0059] It should be noted that the above embodiments are only used to illustrate the present invention. The models in the above steps can be modified or replaced without affecting the creative idea of ​​the present invention. The modified models will not cause their solutions to deviate from the scope of the embodiments of the present invention.

Claims

1. A method for optimizing the parameters of a phase compensation device for electrified railways, specifically including the following steps: (1) Based on the factors affecting the resonance point of the electrified railway power supply system, a model of the railway power supply system is established and the model parameters are initialized; (2) Based on the control effect of the power electronic equipment in the in-phase compensation device and the premise of normal power supply to the locomotive, set the range of electrical quantity parameters of the components in the in-phase compensation device and the control parameters of the controller. (3) Set the range of harmonic order variation of the power supply system [h1, h2], where h1 is the minimum value of the harmonic order variation range and h2 is the maximum value of the harmonic order variation range; (4) When the harmonic order of the power supply system changes to the minimum value, the inductance value and capacitance value of the in-phase compensation device and the control parameters of the controller are used to form the system node admittance matrix when it changes from low to high within the set range. (5) The eigenvalues ​​of the system node admittance matrix corresponding to different parameters are obtained by calculation; (6) Based on h1=h1+Δh, where Δh is the operation step size, the computer determines whether h1 is less than or equal to h2. If so, return to step (4). (7) The harmonic order and impedance amplitude of the resonant point corresponding to the maximum eigenvalue under different parameters are obtained by calculation; (8) Using the harmonic order and impedance amplitude, plot the resonance characteristic curve for each parameter; (9) By measuring the actual harmonic voltage and harmonic current on site, the characteristic harmonic frequency band of the locomotive and the in-phase compensation device is set. (10) The optimal solution of the parameters of each component in the in-phase compensation device is obtained by using the particle swarm optimization algorithm to set the optimization target of the in-phase compensation device. (11) Initialize the particle swarm parameters and randomly initialize the position and velocity of each particle in the in-phase compensation device; (12) Calculate the objective function value of each particle in each parameter of the in-phase compensation device; (13) Update the value of each parameter particle of the in-phase compensation device according to the objective function value; (14) The computer determines whether the error of the optimal solution for each parameter is less than the given limit or whether the number of iterations is satisfied. If not, return to step (12). (15) Output the optimal solution and plot the resonance curve of the in-phase compensation device corresponding to the optimal solution of each parameter.

2. The parameter optimization design method for an electrified railway in-phase compensation device according to claim 1, characterized in that: The modeling of the railway power supply system includes establishing models of in-phase compensation devices, transmission lines, locomotives, and transformers. The in-phase compensation device modeling needs to consider the influencing factors such as the dead time of the power electronic converter, switching time, harmonic distribution, and control strategy. The transmission line modeling needs to consider the standing wave effect. The locomotive model needs to consider the locomotive load, equivalent impedance, and harmonic distribution. The transformer model needs to consider hysteresis loss and eddy current loss.

3. The parameter optimization design method for an electrified railway in-phase compensation device according to claim 1, characterized in that: The range of electrical parameters of the components and control parameters of the controller in the in-phase compensation device includes the range of values ​​for inductor A [L]. A1 L A2 ], L A1 L is the minimum value in the range of inductance A. A2 The maximum value within the range of inductor A; the range of inductor B is [L]. B1 L B2 ], L B1 L is the minimum value in the range of inductance B. B2 The maximum value of inductor B is defined as the maximum value within its range; the capacitance range is defined as [C1, C2], where C1 is the minimum value within its range and C2 is the maximum value within its range; the proportional and integral parameter ranges of the proportional-integral controller are set, with the proportional parameter range [K]. P1 K P2 ], K P1 K is the minimum value in the range of the proportional parameter. P2 The maximum value within the range of the proportional parameter; the range of the integral parameter [K] I1 K I2 ], K I1 K is the minimum value in the range of the integration parameter. I2 This represents the maximum value within the range of values ​​for the integration parameter.

4. The parameter optimization design method for an electrified railway in-phase compensation device according to claim 1, characterized in that: The system node admittance matrix is ​​a square matrix of the following form: In the node admittance matrix, the subscripts of all elements represent the node numbers of the system, Y 11 Y represents the self-admittance of the first node of the system. 22 Y represents the self-admittance of the second node in the system. nn Y represents the self-admittance of the nth node in the system. 12 Y 21 Y represents the mutual admittance between the first node and the second node. 1n Y n1 Y represents the mutual admittance between the 1st node and the nth node. 2n Y n2 This represents the mutual admittance between the second node and the nth node.

5. The parameter optimization design method for an electrified railway in-phase compensation device according to claim 1, characterized in that: The optimization objective of the in-phase compensation device is to avoid the characteristic harmonic frequency band of the locomotive by using the resonant point of the power supply system, and to obtain the in-phase compensation device with the lowest cost under the premise of meeting the compensation requirements, providing normal power supply to the locomotive and achieving good waveform control effect.

6. The parameter optimization design method for an electrified railway in-phase compensation device according to claim 1, characterized in that: The initialized particle swarm parameters include the particle swarm size N, the particle dimension (i.e., the number of in-phase compensation device parameters D), the total number of iterations M, the inertia weight ω, and the learning factors c1 and c2; the random initialization of the particle position and velocity includes randomly initializing the position X of the i-th particle. id The velocity V of the i-th particle id The optimal position P of the i-th particle id Optimal position P of the group d d = 1, 2, ..., D; i = 1, 2, ..., N, where position represents the value of each component parameter and speed represents the change in parameter value.

7. The parameter optimization design method for an electrified railway in-phase compensation device according to claim 1, characterized in that: The calculation of the objective function values ​​of particles in each parameter of the in-phase compensation device includes the optimal objective f of the i-th particle. id and the group optimal objective f d d = 1, 2, ..., D; i = 1, 2, ..., N, that is, whether the harmonic order of the system resonance point deviates from the characteristic harmonic frequency band [T1, T2] of the locomotive and the in-phase compensation device, where T1 represents the minimum harmonic order of the characteristic harmonic frequency band and T2 represents the maximum harmonic order of the characteristic harmonic frequency band.

8. The parameter optimization design method for an electrified railway in-phase compensation device according to claim 1, characterized in that: The updated in-phase compensation device takes values ​​for each parameter particle, including updating the velocity and position of each parameter particle, wherein the velocity update formula is: The position update formula is d = 1, 2, ..., D; i = 1, 2, ..., N; the m in the upper right corner of each symbol represents the value of the m-th iteration, m ≤ M, rand1(), rand2() represent random numbers in the interval [0, 1].

9. The parameter optimization design method for an electrified railway in-phase compensation device according to claim 1, characterized in that: The judgment formula for the given limit is: ε is less than or equal to 10 -2 of decimals.

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