A method and device for monitoring abnormal braking resistance in a train traction system

Abstract

This invention belongs to the technical field of train traction systems, and relates to a method and device for monitoring abnormal braking resistance in a train traction system. The method includes constructing a normal R / T curve band for the braking resistance during simulated train operation and performing real-time monitoring of the braking resistance status during actual train operation. Constructing the normal R / T curve band includes obtaining the braking resistance value R. i Obtain the braking resistor thermal resistance model to predict its relationship with R. i The braking resistor temperature T at the corresponding time i , using (R i ,T i The dataset is used to construct a normal R / T curve band for the braking resistor; real-time monitoring of the braking resistor status includes acquiring the coordinate points of the real-time status parameters (R) of the braking resistor. a ,T a ), determine (R) a ,T a If the R / T curve indicates that the braking resistor is within the normal operating range, an abnormality warning is automatically triggered. This invention solves the problem that relying solely on a single status parameter cannot accurately identify abnormal conditions in the braking resistor, enabling timely and accurate monitoring of whether an abnormality has occurred.

Description

Technical Field

[0001] This invention belongs to the technical field of train traction system, specifically relating to a method and device for monitoring abnormal braking resistance in a train traction system. Background Technology

[0002] When a subway car is going downhill or in other situations requiring deceleration or stopping, the onboard electric motor stops drawing power from the grid and becomes a generator. During the power generation process, the motor generates a counter-torque that causes the car to decelerate. The generated electricity, which cannot be absorbed by the grid, is converted into heat energy by the braking resistor and dissipated. The subway car traction converter mainly consists of a rectifier, charging and discharging unit, filter reactor, intermediate support capacitor, inverter unit, chopper unit, braking resistor, and control unit. The braking resistor generates a large amount of heat during braking. Fans are usually installed for auxiliary cooling, but if the heat cannot be effectively dissipated into the atmosphere in a timely manner, it will accumulate inside the braking resistor, inevitably causing its temperature to rise. In severe cases, this can lead to the burning out of the braking resistor element. Therefore, it is necessary to monitor the braking resistor's condition to ensure its safe and stable operation.

[0003] Currently, there are two main methods for monitoring abnormal train braking resistance:

[0004] The first method relies on temperature sensors. Temperature sensors are deployed around the braking resistor to collect its temperature, which is then compared to a set temperature threshold to monitor for anomalies. For example, patent CN112721902B collects the temperature signal of the braking resistor element while simultaneously monitoring air parameters at the air inlet or outlet of the train's braking resistor to comprehensively determine its operating status. However, this method requires additional temperature sensors, resulting in higher hardware costs. Furthermore, the temperature sensors operate in harsh environments with high temperatures and voltages, increasing the likelihood of sensor failure and affecting monitoring accuracy.

[0005] The second method involves not using a temperature sensor, but instead using existing train operating parameters to convert them into characteristic indicators of the braking resistor for monitoring. These characteristic indicators mainly include the braking resistor temperature and the braking resistor resistance value. For example, patent CN110949359B first obtains the accumulated heat value after the braking resistor is put into operation, then calculates the temperature rise value, adds the temperature rise value to the initial temperature, and then compares it with a set temperature threshold to achieve abnormal temperature monitoring of the braking resistor. However, this method is usually only applicable to temperature rises caused by circuit faults. If the temperature rise is caused by a fault in some hardware components of the braking resistor box, such as a cooling fan, the method is not applicable. In addition, as in patent CN106443241B, the power of the DC side feedback power and the braking energy stored in the intermediate support capacitor during the braking process of the target traction system are obtained in real time. The total power generated by braking is converted to the DC side to obtain the converted total power, and then the real-time power consumption of the braking resistor is calculated. Finally, the voltage value of the braking resistor is obtained, the resistance value of the braking resistor is calculated, and it is compared with the set threshold to determine the status of the braking resistor. However, this method usually sets a relatively large and constant threshold, and often does not distinguish between working conditions but includes the entire process. In some cases, the resistance value may not need to reach the threshold to cause a fault, and when the threshold is reached and an alarm is triggered, the health status of the braking resistor is often not optimistic.

[0006] As can be seen from the above, relying solely on the single state parameter of the braking resistor will inevitably reduce the monitoring accuracy due to interference from changes in the surrounding environment and operating conditions, and will not be able to accurately identify abnormal conditions of the braking resistor. Therefore, it is necessary to develop a more refined method for monitoring abnormal braking resistor conditions. Summary of the Invention

[0007] In view of the shortcomings of related technologies, the present invention provides a method and device for monitoring abnormal braking resistance in a train traction system, which aims to solve the problem that relying solely on a single state parameter cannot accurately identify abnormal braking resistance conditions, and improve the accuracy of abnormal braking resistance monitoring.

[0008] This invention provides a method for monitoring abnormal braking resistance in a train traction system, comprising the following steps:

[0009] Constructing a normal R / T curve for the braking resistor during train simulation, specifically including:

[0010] Obtain the resistance value R of the braking resistor i To obtain the temperature rise surface and heat dissipation curve of the braking resistor, a thermal resistance model of the braking resistor is obtained, which is then used to predict the relationship between the braking resistor and R during train simulation operation. i The braking resistor temperature T at the corresponding time i To obtain the coordinate points of the braking resistor state parameters (R) at the same moment. i ,T i); where i is the sample dimension, i = 1, 2, ..., m;

[0011] Summarize the coordinates of the braking resistor state parameters at multiple time points (R) i ,T i This is used to form a dataset, and then to construct a normal R / T curve band for the braking resistor.

[0012] Real-time monitoring of the braking resistor status is performed during actual train operation and includes:

[0013] Obtain the real-time resistance value R of the braking resistor a Based on the braking resistor thermal resistance model, predict the actual operation of the train and R. a Real-time temperature T of the braking resistor at the corresponding moment a To obtain the coordinates of the real-time state parameters of the braking resistor (R) a ,T a );

[0014] Determine the coordinates of the real-time status parameters of the braking resistor (R) a ,T a If the braking resistor is within the normal R / T curve range, then the braking resistor is in normal condition; otherwise, an abnormal warning for the braking resistor will be automatically triggered.

[0015] In some embodiments, the temperature rise surface and heat dissipation curve of the braking resistor are obtained to obtain a thermal resistance model of the braking resistor, including:

[0016] Monitor the real-time power P of the traction converter chopper circuit; continuously monitor the temperature T of the braking resistor when it is under braking conditions. s1 To obtain the temperature rise surface of the braking resistor; continuously monitor the temperature T of the braking resistor when it is in the brake release condition. s2 In order to obtain the heat dissipation curve of the braking resistor;

[0017] A thermal resistance model for the temperature rise stage of the braking resistor as shown in equation (1) is established, and a thermal resistance model for the heat dissipation stage of the braking resistor as shown in equation (2) is established. By combining the temperature rise surface and the heat dissipation curve, the thermal resistance parameter F and the heat capacity parameter C of the braking resistor are fitted.

[0018]

[0019]

[0020] In equations (1)-(2), T r Let T0 be the ambient temperature, T0 be the initial temperature of the detected braking resistor immediately after the braking condition is released, e be the natural constant, and t be the ambient temperature. s1 t represents the detection time of the braking resistor when it is in braking condition. s2All of these are the detection times when the braking resistor is in the released braking condition;

[0021] Based on equations (1), (2) and the fitted thermal resistance parameter F and thermal capacity parameter C of the braking resistor, the discretized thermal resistance model of the braking resistor shown in equation (3) is obtained.

[0022] T k+1 =(T k -T r )×e (-t / FC) +P×F×(1-e (-t / FC) )+T r (3);

[0023] In equation (3), T r Let T be the ambient temperature, e be the natural constant, and t be the discrete time. k T is the temperature of the braking resistor at time k; k+1 Let be the temperature of the braking resistor at time k+1.

[0024] In some embodiments, after obtaining the discretized braking resistor thermal resistance model shown in equation (3), the braking resistor thermal resistance model is verified, including:

[0025] Using the discretized braking resistor thermal resistance model shown in Equation (3), the predicted temperature of the braking resistor during a preset time period during the train simulation operation is calculated; at the same time, the actual temperature of the braking resistor during the preset time period is continuously detected.

[0026] Compare the predicted temperature of the braking resistor with the measured temperature of the braking resistor within the preset time period; if the temperature difference between the two is not greater than the preset temperature error ΔT, the thermal resistance model of the braking resistor is verified as qualified; if the temperature difference between the two is greater than the preset temperature error ΔT, the thermal resistance model of the braking resistor is not verified as qualified, and the temperature rise surface and heat dissipation curve of the braking resistor are re-obtained to obtain the thermal resistance model of the braking resistor again.

[0027] In some embodiments, the braking resistor value R at the corresponding time point is obtained. i ,include:

[0028] Monitor the voltage U across the intermediate support capacitor i Monitor the chopper current of the traction converter chopper circuit and perform envelope analysis to obtain the upper envelope of the chopper current, thereby obtaining the chopper current I. i ; Calculate the braking resistor value R according to equation (4) i ;

[0029] R i =U i / I i (4).

[0030] In some embodiments, constructing a normal R / T curve band for the braking resistor also includes:

[0031] Using the state parameter coordinates of the braking resistor (R) i ,T i The dataset was used to fit the normal R / T curve of the braking resistor, including:

[0032] Establish based on the braking resistor resistance value R i The functional equation is expressed as equation (5); where n is the polynomial order, θ0 is the constant term, and θ j Here are the coefficients of the polynomial, j = 1, 2, ..., n;

[0033] f(R i )=θ0+θ1R i +θ2R i 2 +…+θ j R i n (5);

[0034] The coordinate points of the state parameters of each braking resistor (R) i ,T i The sum of squared errors S is expressed as equation (6); the functional equation is linearized by removing R. i The quadratic and above terms; according to the principle of least squares, by minimizing the sum of squared errors S, the optimal solution of the constant term θ0 and the coefficient of the first term θ1 is calculated, and then the normal R / T curve of the braking resistor is obtained, which is expressed as equation (7); where T is the temperature of the braking resistor and R is the resistance of the braking resistor.

[0035]

[0036] T = θ0 + θ1R (7);

[0037] Based on the normal R / T curve of the braking resistor, and combined with the coordinate points of the braking resistor state parameters (R... i ,T i The distribution of the dataset relative to the normal R / T curve of the braking resistor is used to obtain the tolerance w, so as to obtain the upper limit warning line of the braking resistor shown in equation (8) and the lower limit warning line of the braking resistor shown in equation (9); the area between the upper limit warning line and the lower limit warning line of the braking resistor is the normal R / T curve band of the braking resistor; when the real-time state parameter coordinate point of the braking resistor (R a ,T a When the braking resistor is outside the normal R / T curve band, an abnormal warning for the braking resistor will be automatically triggered.

[0038] T max =θ0+θ1R+w (8);

[0039] T min =θ0+θ1R-w (9).

[0040] In some embodiments, a slight abnormality warning deviation w1 is set to obtain the first warning line for slight abnormality of braking resistance shown in equation (10) and the second warning line for slight abnormality of braking resistance shown in equation (11); a moderate abnormality warning deviation w2 is set to obtain the first warning line for moderate abnormality of braking resistance shown in equation (12) and the second warning line for moderate abnormality of braking resistance shown in equation (13).

[0041] T max1 =θ0+θ1R+w+w1 (10);

[0042] T min1 =θ0+θ1R-w-w1 (11);

[0043] T max2 =θ0+θ1R+w+w1+w2 (12);

[0044] T min2 =θ0+θ1R-w-w1-w2 (13);

[0045] When (R) a ,T a ) Located in the area between the first warning line for minor abnormalities in braking resistance and the upper limit warning line for braking resistance, or (R a ,T a When the area is located between the lower limit warning line of the braking resistor and the second warning line for minor abnormality of the braking resistor, the minor abnormality warning of the braking resistor will be automatically triggered.

[0046] When (R) a ,T a ) Located in the area between the first warning line for moderate abnormality in braking resistance and the first warning line for slight abnormality in braking resistance, or (R a ,T a When the brake resistance is located in the area between the second warning line for minor abnormality and the second warning line for moderate abnormality, the moderate abnormality warning for brake resistance will be automatically triggered.

[0047] When (R) a ,T a When the area is outside the region between the first warning line and the second warning line for moderate abnormality in braking resistance, a severe abnormality warning for braking resistance will be automatically triggered.

[0048] In some embodiments, during the real-time monitoring step of the braking resistor status, the real-time resistance value R of the braking resistor is obtained. a This includes real-time acquisition of the voltage U across the intermediate support capacitor.a The chopping current I in the traction converter chopper circuit a The braking resistor value R is calculated according to equation (14). a ;

[0049] R a =U a / I a (14).

[0050] In some embodiments, during the real-time monitoring step of the braking resistor status, the actual operating conditions of the train and R are predicted based on the braking resistor thermal resistance model. a Real-time temperature T of the braking resistor at the corresponding moment a This includes acquiring the real-time power P and ambient temperature T of the traction converter chopper circuit. r Based on the discretized braking resistor thermal resistance model shown in equation (3), the actual operation of the train and R are predicted. a Real-time temperature T of the braking resistor at the corresponding moment a .

[0051] In some embodiments, when the method for monitoring abnormal braking resistance in a train traction system is used for monitoring abnormal braking resistance when the fan is on, the steps of constructing a normal R / T curve band for the braking resistance and the step of real-time monitoring of the braking resistance are both performed when the fan is on; when the method for monitoring abnormal braking resistance in a train traction system is used for monitoring abnormal braking resistance when the fan is off, the steps of constructing a normal R / T curve band for the braking resistance and the step of real-time monitoring of the braking resistance are both performed when the fan is off.

[0052] The present invention also provides a train traction system braking resistance abnormal monitoring device, including a memory, a processor, and a computer program stored in the memory and executable on the processor; when the processor executes the computer program, it implements the train traction system braking resistance abnormal monitoring method as described above.

[0053] Based on the above technical solution, the train traction system braking resistor abnormality monitoring method and device in this embodiment of the invention achieves more refined braking resistor abnormality monitoring by fusing two state parameters: the real-time resistance value of the braking resistor and the real-time predicted temperature of the braking resistor. It can detect whether the braking resistor is abnormal in a timely and accurate manner, solving the problem that the current method cannot accurately identify the abnormality of the braking resistor by relying on a single state parameter. This improves the accuracy of braking resistor abnormality monitoring and has high robustness. Attached Figure Description

[0054] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0055] Figure 1 This is a flowchart of the abnormal monitoring method for braking resistance of the train traction system according to the present invention;

[0056] Figure 2 This is a schematic diagram of the temperature rise surface of the braking resistor obtained in the step of constructing the normal R / T curve band of the braking resistor in this invention.

[0057] Figure 3 This is a schematic diagram of the heat dissipation curve of the braking resistor obtained in the step of constructing the normal R / T curve band of the braking resistor in this invention.

[0058] Figure 4 This is a schematic diagram comparing the predicted and measured results of the braking resistor temperature in the step of constructing the normal R / T curve band of the braking resistor in this invention.

[0059] Figure 5 This is a schematic diagram of the chopping current of the traction converter chopping circuit monitored during the step of constructing the normal R / T curve band of the braking resistor in this invention.

[0060] Figure 6 To Figure 5 The diagram shows the result of the upper envelope of the chopper current after envelope analysis.

[0061] Figure 7 This is a schematic diagram showing the result of the braking resistor resistance value in the step of constructing the normal R / T curve band of the braking resistor in this invention;

[0062] Figure 8 In the step of constructing the normal R / T curve band of the braking resistor in this invention, the coordinate points of the braking resistor state parameter (R) are... i ,T i A schematic diagram showing the distribution of the dataset;

[0063] Figure 9 This is a schematic diagram of the normal R / T curve band of the braking resistor and a schematic diagram of the abnormal warning line of the braking resistor according to the present invention. Detailed Implementation

[0064] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0065] In the description of this invention, it should be understood that the terms "center", "lateral", "longitudinal", "upper", "lower", "top", "bottom", "inner", "outer", "left", "right", "front", "rear", "vertical", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0066] The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature.

[0067] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0068] refer to Figures 1-9 As shown, the present invention provides a method for monitoring abnormal braking resistance in a train traction system, comprising two main steps: constructing a normal R / T curve band for the braking resistance and real-time monitoring of the braking resistance status.

[0069] The steps for constructing a normal R / T curve band for the braking resistor are performed during train simulation operation, specifically including:

[0070] Obtain the resistance value R of the braking resistor i The temperature rise surface and heat dissipation curve of the braking resistor are obtained to derive a thermal resistance model for the braking resistor. It can be understood that the temperature rise surface reflects the temperature rise performance of the braking resistor during operation, while the heat dissipation curve reflects its heat dissipation performance when it is not in operation. Based on this thermal resistance model, it is possible to predict the relationship between the braking resistor and R during simulated train operation. i The braking resistor temperature T at the corresponding time iThus, the coordinate points of the braking resistor state parameters (R) at the same moment are obtained. i ,T i ); where i is the sample dimension, i = 1, 2, ..., m; in this way, the braking resistor value R at multiple time points is obtained. i And simultaneously predict the braking resistor temperature T i To generate a large number of braking resistor state parameter coordinate points (R) i ,T i )data;

[0071] Summarize the coordinates of the braking resistor state parameters at multiple time points (R) i ,T i To form a dataset, statistical analysis is performed on the dataset to construct a normal R / T curve band for the braking resistor.

[0072] The steps for real-time monitoring of the braking resistor status are performed during actual train operation and include:

[0073] Obtain the real-time resistance value R of the braking resistor a Based on the braking resistor thermal resistance model obtained in the step of constructing the normal R / T curve band of the braking resistor, the actual operation of the train and the R / T curve are predicted. a Real-time temperature T of the braking resistor at the corresponding moment a This allows us to obtain the coordinates of the real-time state parameters of the braking resistor during actual train operation (R). a ,T a );

[0074] Determine the coordinates of the real-time status parameters of the braking resistor (R) a ,T a Is it located within the normal R / T curve range of the braking resistor? If the real-time status parameter coordinate point of the braking resistor (R...) a ,T a If the real-time status parameter coordinate point (R) is within the normal R / T curve band of the braking resistor, then the braking resistor status is normal, and monitoring continues; if the real-time status parameter coordinate point of the braking resistor (R) is within the normal R / T curve band, then the braking resistor status is normal, and monitoring continues; a ,T a If the R / T curve exceeds the normal range of the braking resistor, an abnormal warning for the braking resistor will be automatically triggered.

[0075] To further explain, the construction of the normal R / T curve band of the braking resistor during train simulation is intended to provide a judgment standard for real-time monitoring of the braking resistor status during actual train operation; thus, it is not necessary to use an additional temperature sensor when monitoring the braking resistor status in real time, reducing hardware costs.

[0076] The above illustrative embodiment achieves more refined brake resistor anomaly monitoring by fusing two state parameters: the real-time resistance value of the brake resistor and the real-time predicted temperature of the brake resistor. It can detect whether the brake resistor is abnormal in a timely and accurate manner, with fast identification speed and high accuracy. Therefore, it can solve the problem that relying on a single state parameter cannot accurately identify brake resistor anomalies, reduce the possibility that the monitoring accuracy will decrease due to the influence of changes in the surrounding environment and operating conditions on a single state parameter, improve the accuracy of brake resistor anomaly monitoring, and has high robustness.

[0077] refer to Figures 1-3 As shown, in some embodiments, the temperature rise surface and heat dissipation curve of the braking resistor are obtained to obtain the thermal resistance model of the braking resistor, including:

[0078] When the braking resistor is working, i.e., under braking conditions, it is in the temperature rise stage; monitor the real-time power P of the traction converter chopper circuit; use a high-voltage (2000V) temperature measuring device to continuously monitor the temperature T of the braking resistor under braking conditions. s1 This forms a set of temperature data points for the braking resistor based on power and time. After fitting, the temperature rise surface of the braking resistor can be obtained, such as... Figure 2 As shown;

[0079] When the braking resistor is not working, i.e., when the braking resistor is in the released braking condition, the braking resistor is in the heat dissipation stage; a high-voltage (2000V) temperature measuring device is used to continuously monitor the temperature T of the braking resistor when the braking is in the released braking condition. s2 This forms a time-based temperature data set for the braking resistor. After fitting the data, the heat dissipation curve of the braking resistor can be obtained, such as... Figure 3 As shown;

[0080] A thermal resistance model for the temperature rise stage of the braking resistor as shown in equation (1) is established, and a thermal resistance model for the heat dissipation stage of the braking resistor as shown in equation (2) is established. By combining the temperature rise surface and heat dissipation curve of the braking resistor, the thermal resistance parameter F and heat capacity parameter C of the braking resistor can be fitted with mathematical analysis tools such as MATLAB.

[0081]

[0082]

[0083] In equations (1)-(2), T r Let T0 be the ambient temperature, T0 be the initial temperature of the detected braking resistor immediately after the braking condition is released, e be the natural constant, and t be the ambient temperature. s1 t represents the detection time of the braking resistor when it is in braking condition. s2 All of these are the detection times when the braking resistor is in the released braking condition;

[0084] Based on equations (1), (2) and the fitted thermal resistance parameter F and thermal capacity parameter C of the braking resistor, the discretized thermal resistance model of the braking resistor shown in equation (3) is obtained.

[0085] T k+1 =(T k -T r )×e (-t / FC) +P×F×(1-e (-t / FC) )+T r (3);

[0086] In equation (3), T r Let T be the ambient temperature, e be the natural constant, and t be the discrete time. k T is the temperature of the braking resistor at time k; k+1 Let be the temperature of the braking resistor at time k+1.

[0087] The above illustrative embodiment realizes the fitting calculation of the thermal resistance parameter F and the thermal capacity parameter C of the braking resistor, thereby obtaining an accurate thermal resistance model of the braking resistor, and thus enabling accurate prediction of the braking resistor temperature.

[0088] refer to Figure 4 As shown, in some embodiments, after obtaining the discretized braking resistor thermal resistance model shown in equation (3), the braking resistor thermal resistance model is verified, including:

[0089] Using the discretized braking resistor thermal resistance model shown in equation (3), the predicted temperature of the braking resistor during a preset time period in the train simulation operation is calculated, such as... Figure 4 As shown by the orange line; simultaneously, a high-voltage (2000V) temperature measuring device is used to continuously detect the actual temperature of the braking resistor within this preset time period, such as... Figure 4 The blue line indicates this; and the predicted temperature and the measured temperature of the braking resistor are displayed simultaneously.

[0090] By comparing the predicted temperature of the braking resistor with the measured temperature of the braking resistor within the preset time period, the temperature difference between the two is calculated. Figure 4 As shown by the yellow line; if the temperature difference between the two is not greater than the preset temperature error ΔT, the verification of the braking resistor thermal resistance model is qualified; if the temperature difference is greater than the preset temperature error ΔT, the verification of the braking resistor thermal resistance model is unqualified, and the temperature rise surface and heat dissipation curve of the braking resistor are re-obtained to obtain the braking resistor thermal resistance model again. The preset temperature error ΔT can be set with reference to theoretical analysis and practical experience, and is not limited in this invention. Figure 4 In the embodiment shown, the temperature difference between the predicted temperature and the measured temperature of the braking resistor does not exceed 10°C, which, after evaluation, meets the verification requirements of the braking resistor thermal resistance model.

[0091] The above illustrative embodiments further ensure the accuracy of the braking resistor thermal resistance model, thereby ensuring accurate prediction of the braking resistor temperature.

[0092] refer to Figure 1 , Figures 5-7 As shown, in some embodiments, the braking resistor resistance value R is obtained. i ,include:

[0093] Monitor the voltage U across the intermediate support capacitor i ;

[0094] The chopper current in the traction converter chopper circuit is monitored, and envelope analysis is performed on the chopper current to obtain an approximately smooth upper envelope. Furthermore, it is explained that the amplitude of a high-frequency amplitude-modulated signal varies according to the low-frequency modulation signal. If the peaks of the high-frequency amplitude-modulated signal are connected, a curve corresponding to the low-frequency modulation signal can be obtained; this curve is the upper envelope. The upper envelope reflects the overall trend of the chopper current under braking mode. The chopper current I can be obtained through the upper envelope. i ;

[0095] The braking resistor R is calculated according to equation (4). i ;

[0096] R i =U i / I i (4).

[0097] The above illustrative embodiment utilizes the voltage across the intermediate support capacitor and the chopping current of the traction converter chopping circuit to achieve soft measurement of the braking resistor value; by analyzing the envelope of the chopping current, the braking resistor value R can be determined. i Furthermore, the braking resistor resistance value R was increased. i Data accuracy.

[0098] refer to Figure 1 , Figure 8 , Figure 9 As shown, in some embodiments, constructing a normal R / T curve band for the braking resistor also includes:

[0099] Using the state parameter coordinates of the braking resistor (R) i ,T i The dataset was used to fit the R / T curve of the braking resistor under normal conditions; by observation... Figure 8 The coordinates of the braking resistor state parameters shown are (R) i ,T i The dataset reveals a strong linear relationship between the braking resistor's resistance and its temperature. The fitting of the R / T curve for a braking resistor in normal operating condition includes:

[0100] Establish based on the braking resistor resistance value R i The functional equation is expressed as equation (5); where n is the polynomial order, θ0 is the constant term, and θ j Here are the coefficients of the polynomial, j = 1, 2, ..., n;

[0101] f(R i )=θ0+θ1R i +θ2R i 2 +…+θ j R i n (5);

[0102] The coordinate points of the state parameters of each braking resistor (R) i ,T i The sum of squared errors S is expressed as equation (6); the functional equation is linearized by removing R. i The quadratic term and above; according to the principle of least squares, by minimizing the sum of squared errors S, the optimal function matching of the data is found, that is, the coefficients of the optimal function should make the sum of squared errors S reach a minimum value, thereby solving the optimal solution of the constant term θ0 and the coefficient of the first term θ1, and then obtaining the normal R / T curve of the braking resistor, expressed as equation (7); where T is the temperature of the braking resistor and R is the resistance of the braking resistor;

[0103]

[0104] T = θ0 + θ1R (7);

[0105] Combination Figure 9 As shown, based on the normal R / T curve of the braking resistor, and combined with the coordinate points of the braking resistor state parameters (R... i ,T i The distribution of the dataset relative to the normal R / T curve of the braking resistor is used to obtain the tolerance w, so as to obtain the upper limit warning line of the braking resistor shown in equation (8) and the lower limit warning line of the braking resistor shown in equation (9); the area between the upper limit warning line and the lower limit warning line of the braking resistor is the normal R / T curve band of the braking resistor; when the real-time state parameter coordinate point of the braking resistor (R a ,T a When the braking resistor is outside the normal R / T curve band, an abnormal warning for the braking resistor will be automatically triggered.

[0106] T max =θ0+θ1R+w (8);

[0107] T min =θ0+θ1R-w (9).

[0108] The above illustrative embodiment realizes the construction of the normal R / T curve band of the braking resistor.

[0109] refer to Figure 1 , Figure 9 As shown, in some embodiments, a slight abnormality warning deviation w1 is set to obtain the first warning line for slight abnormality of braking resistance shown in equation (10) and the second warning line for slight abnormality of braking resistance shown in equation (11); a moderate abnormality warning deviation w2 is set to obtain the first warning line for moderate abnormality of braking resistance shown in equation (12) and the second warning line for moderate abnormality of braking resistance shown in equation (13); thereby, a hierarchical setting for braking resistance abnormality warning is formed.

[0110] T max1 =θ0+θ1R+w+w1 (10);

[0111] T min1 =θ0+θ1R-w-w1 (11);

[0112] T max2 =θ0+θ1R+w+w1+w2 (12);

[0113] T min2 =θ0+θ1R-w-w1-w2 (13).

[0114] When the real-time state parameter coordinate point of the braking resistor (R) a ,T a ) Located in the area between the first warning line for minor abnormalities in braking resistance and the upper limit warning line for braking resistance, or (R a ,T a When the area is located between the lower limit warning line of the braking resistor and the second warning line for minor abnormality of the braking resistor, a minor abnormality warning for the braking resistor will be automatically triggered.

[0115] When the real-time state parameter coordinate point of the braking resistor (R) a ,T a ) Located in the area between the first warning line for moderate abnormality in braking resistance and the first warning line for slight abnormality in braking resistance, or (R a ,T a When the brake resistance is located in the area between the second warning line for minor abnormality and the second warning line for moderate abnormality, the moderate abnormality warning for brake resistance will be automatically triggered.

[0116] When the real-time state parameter coordinate point of the braking resistor (R) a ,T a When the area is outside the region between the first warning line and the second warning line for moderate abnormality in braking resistance, a severe abnormality warning for braking resistance will be automatically triggered.

[0117] For example, when the braking resistor ages abnormally, its resistance value usually increases, which will cause the real-time status parameter coordinate point (R) of the braking resistor to change. a ,T a If the R / T curve exceeds the normal range for braking resistor conditions and is located below the curve, such as... Figure 9 Point A is shown in the diagram.

[0118] When the fan malfunctions, resulting in insufficient airflow, or when the duct is blocked, causing an increase in thermal resistance and heat capacity parameters, the actual temperature of the braking resistor will be higher than the predicted temperature. This is visually manifested as an increase in the braking resistor's resistance value, ultimately leading to a change in the real-time status parameter coordinates (R...). a ,T a If the R / T curve exceeds the normal range for braking resistor conditions and is located below the curve, such as... Figure 9 Point A is shown in the diagram.

[0119] When the braking resistor undergoes abnormal deformation due to mechanical stress, leading to a short circuit, its resistance value will decrease, causing the real-time state parameter coordinate point (R) of the braking resistor to drop. a ,T a If the R / T curve exceeds the normal range for braking resistor conditions and is located above the curve, such as... Figure 9 Point B is shown in the diagram.

[0120] The above illustrative embodiment, by setting graded levels for the degree of abnormality in the braking resistor, can quickly identify the warning level when an abnormality in the braking resistor is detected.

[0121] In some embodiments, during the real-time monitoring step of the braking resistor status, the real-time resistance value R of the braking resistor is obtained. a This includes real-time acquisition of the voltage U across the intermediate support capacitor. a The chopping current I in the traction converter chopper circuit a The braking resistor value R is calculated according to equation (14). a This illustrative embodiment demonstrates the braking resistor value R during actual train operation. a Real-time acquisition.

[0122] R a =U a / I a (14).

[0123] In some embodiments, during the real-time monitoring step of the braking resistor status, the actual operating conditions of the train and R are predicted based on the braking resistor thermal resistance model. a Real-time temperature T of the braking resistor at the corresponding moment a This includes acquiring the real-time power P and ambient temperature T of the traction converter chopper circuit. rBased on the discretized braking resistor thermal resistance model shown in equation (3), the actual operation of the train and R are predicted. a Real-time temperature T of the braking resistor at the corresponding moment a This illustrative embodiment realizes the connection between the actual operation of the train and R. a Real-time temperature T of the braking resistor at the corresponding moment a Real-time prediction.

[0124] In some embodiments, when the method for monitoring abnormal braking resistance in a train traction system is used for monitoring abnormal braking resistance when the fan is on, the steps of constructing a normal R / T curve band for the braking resistance and the step of real-time monitoring of the braking resistance are both performed when the fan is on. Similarly, when the method for monitoring abnormal braking resistance in a train traction system is used for monitoring abnormal braking resistance when the fan is off, the steps of constructing a normal R / T curve band for the braking resistance and the step of real-time monitoring of the braking resistance are both performed when the fan is off. This illustrative embodiment can achieve abnormal braking resistance monitoring under both fan-on and fan-off operating conditions.

[0125] The present invention also provides a device for monitoring abnormal braking resistance in a train traction system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the aforementioned method for monitoring abnormal braking resistance in a train traction system.

[0126] In summary, the train traction system braking resistor anomaly monitoring method and device of the present invention obtains the braking resistor value through chopper current envelope analysis, accurately predicts the braking resistor temperature through a braking resistor thermal resistance model, and thus forms a normal braking resistor R / T curve band. By judging whether the coordinate point of the real-time state parameter of the braking resistor formed by the real-time resistance value and the real-time predicted temperature of the braking resistor is located within the normal braking resistor R / T curve band, more refined braking resistor anomaly monitoring is achieved. It can detect whether the braking resistor is abnormal in a timely and accurate manner, solves the problem that the current method cannot accurately identify the abnormal situation of the braking resistor by relying on a single state parameter, improves the accuracy of braking resistor anomaly monitoring, and has high robustness.

[0127] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0128] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A method for monitoring abnormal braking resistance in a train traction system, characterized in that, Includes the following steps: The braking resistor is in normal condition. The curved zone, conducted during train simulation, specifically includes: Obtain the resistance value of the braking resistor To obtain the temperature rise surface and heat dissipation curve of the braking resistor, a thermal resistance model of the braking resistor is obtained, which is then used to predict the braking resistance during train simulation operation. The braking resistor temperature at the corresponding time To obtain the coordinate points of the braking resistor state parameters at the same moment. ;in, For sample dimensions, , ,…, The step of obtaining the temperature rise surface and heat dissipation curve of the braking resistor to obtain the thermal resistance model of the braking resistor includes: monitoring the real-time power of the traction converter chopper circuit. Continuously monitor the temperature of the braking resistor when it is in braking condition. To obtain the temperature rise surface of the braking resistor; to continuously monitor the temperature of the braking resistor when it is in the braking release condition. To obtain the heat dissipation curve of the braking resistor; to establish the thermal resistance model of the braking resistor during the temperature rise stage as shown in equation (1), and the thermal resistance model of the braking resistor during the heat dissipation stage as shown in equation (2), and to fit the thermal resistance parameters of the braking resistor by combining the temperature rise surface and the heat dissipation curve. and heat capacity parameters According to equations (1) and (2) and the fitted thermal resistance parameters of the braking resistor and heat capacity parameters The discretized braking resistor thermal resistance model shown in equation (3) is obtained; in equations (1)-(3), For ambient temperature, The initial temperature of the detected braking resistor immediately after the braking condition is released. It is a natural constant. This refers to the detection time length of the braking resistor when it is in braking condition. Both figures represent the detection time length when the braking resistor is in the released braking condition. It is discrete time; for Temperature of the braking resistor at any given moment; for Temperature of the braking resistor at any given moment; (1)； (2)； (3)； Summarize the coordinates of the braking resistor state parameters at multiple time points. To form a dataset, and then construct a normal braking resistor status. Curved strip; Real-time monitoring of the braking resistor status is performed during actual train operation and includes: Obtain the real-time resistance value of the braking resistor Based on the aforementioned braking resistor thermal resistance model, the actual operating conditions of the train are predicted to be... Real-time temperature of the braking resistor at the corresponding moment To obtain the coordinate points of the real-time state parameters of the braking resistor. ; Determine the coordinates of the real-time state parameters of the braking resistor. Is the braking resistor in normal condition? If the circuit is within the curve band, the braking resistor is in normal condition; otherwise, an abnormal warning for the braking resistor will be automatically triggered.

2. The method for monitoring abnormal braking resistance of a train traction system according to claim 1, characterized in that, After obtaining the discretized thermal resistance model of the braking resistor as shown in equation (3), the thermal resistance model of the braking resistor is verified, including: Using the discretized braking resistor thermal resistance model shown in Equation (3), the predicted temperature of the braking resistor during a preset time period during the train simulation operation is calculated; at the same time, the actual temperature of the braking resistor during the preset time period is continuously detected. Compare the predicted temperature of the braking resistor with the measured temperature of the braking resistor within the preset time period; if the temperature difference between the two is not greater than the preset temperature error... If the temperature difference between the two is greater than the preset temperature error, then the verification of the braking resistor thermal resistance model is successful; If the thermal resistance model of the braking resistor fails to pass verification, the temperature rise surface and heat dissipation curve of the braking resistor should be obtained again to re-obtain the thermal resistance model of the braking resistor.

3. The method for monitoring abnormal braking resistance of a train traction system according to claim 1, characterized in that, The method of obtaining the braking resistor resistance value ,include: Monitor the voltage across the intermediate support capacitor Monitor the chopper current of the traction converter chopper circuit and perform envelope analysis to obtain the upper envelope of the chopper current, thereby obtaining the chopper current. ; Calculate the braking resistor value according to equation (4) ; (4)。 4. The method for monitoring abnormal braking resistance of a train traction system according to claim 1, characterized in that, The braking resistor is in normal condition. The curved strip also includes: Using the state parameter coordinates of the braking resistor The dataset was fitted to determine if the braking resistor was in normal condition. Curves, including: Establish based on braking resistor resistance value The functional equation of is expressed as equation (5); where, Let be the order of the polynomial. For constant terms, The coefficients of the polynomial are... , ,…, ; (5)； Coordinate points of each braking resistor's state parameters Sum of squared errors Represented as equation (6); the functional equation is linearized by removing... Quadratic terms and above; according to the principle of least squares, by minimizing the sum of squared errors. Solve for the constant term and coefficient of the first term The optimal solution is obtained, thus confirming the normal state of the braking resistor. The curve is represented by equation (7); where, For the braking resistor temperature, The value of the braking resistor; (6)； (7)； According to the normal state of the braking resistor Curve, combined with the coordinate points of the braking resistor state parameters The dataset is normal relative to the braking resistor state. The distribution of the curve yields the tolerance. To obtain the upper limit warning line of the braking resistor shown in equation (8) and the lower limit warning line of the braking resistor shown in equation (9); the area between the upper limit warning line and the lower limit warning line of the braking resistor is the area where the braking resistor is in normal condition. Curved band; when the real-time state parameter coordinates of the braking resistor are... The braking resistor is in normal condition. When the circuit is outside the curve zone, an abnormal warning for the braking resistor is automatically triggered; (8)； (9)。 5. The method for monitoring abnormal braking resistance of a train traction system according to claim 4, characterized in that, Set minor abnormality warning deviation In order to obtain the first warning line for slight abnormality of braking resistance shown in Equation (10) and the second warning line for slight abnormality of braking resistance shown in Equation (11); Set medium-level abnormal warning deviation In order to obtain the first warning line of moderate abnormality of braking resistance shown in Equation (12) and the second warning line of moderate abnormality of braking resistance shown in Equation (13); (10)； (11)； (12)； (13)； when Located in the area between the first warning line for minor abnormalities in braking resistance and the upper limit warning line for braking resistance, or When the area is located between the lower limit warning line of the braking resistor and the second warning line for minor abnormality of the braking resistor, a minor abnormality warning for the braking resistor will be automatically triggered. when The area located between the first warning line for moderate abnormality in braking resistance and the first warning line for slight abnormality in braking resistance, or When the area is located between the second warning line for minor abnormality of braking resistance and the second warning line for moderate abnormality of braking resistance, the moderate abnormality warning of braking resistance will be automatically triggered. when When the area is outside the region between the first warning line and the second warning line for moderate abnormality in braking resistance, a severe abnormality warning for braking resistance is automatically triggered.

6. The method for monitoring abnormal braking resistance of a train traction system according to claim 1, characterized in that, In the real-time monitoring step of the braking resistor status, the real-time resistance value of the braking resistor is obtained. , This includes real-time acquisition of the voltage across the intermediate support capacitor. Chopping current of the traction converter chopper circuit The braking resistor value is calculated according to formula (14). ; (14)。 7. The method for monitoring abnormal braking resistance of a train traction system according to claim 1, characterized in that, In the real-time monitoring step of the braking resistor status, based on the braking resistor thermal resistance model, the actual operation of the train is predicted to be similar to that of the braking resistor. Real-time temperature of the braking resistor at the corresponding moment This includes acquiring the real-time power of the traction converter chopper circuit. and ambient temperature Based on the discretized braking resistor thermal resistance model shown in equation (3), the actual operation of the train is predicted to be similar to that of the braking resistor. Real-time temperature of the braking resistor at the corresponding moment .

8. The method for monitoring abnormal braking resistance of a train traction system according to claim 1, characterized in that, When the train traction system braking resistor abnormality monitoring method is used to monitor the braking resistor abnormality while the fan is running, the braking resistor is in a normal state. The steps of the curved strip and the real-time monitoring of the braking resistor status are both performed with the fan on. When the train traction system braking resistor abnormality monitoring method is used for braking resistor abnormality monitoring with the fan off, the braking resistor status is normal. Both the curved strip step and the real-time monitoring step of the braking resistor status are performed with the fan off.

9. A device for monitoring abnormal braking resistance in a train traction system, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor; when the processor executes the computer program, it implements the method for abnormal monitoring of braking resistance of a train traction system as described in any one of claims 1-8.

Images