Rail transit vehicle and power supply system real-time identification method and system of alternating current traction network of rail transit vehicle

Abstract

The invention discloses a real-time identification method and system for a power supply system of a rail transit vehicle and an alternating current traction network thereof, and the method comprises the steps: collecting the secondary side network voltage of a high-voltage voltage transformer, obtaining original network voltage data through low-pass filtering, carrying out the data screening, obtaining peak point information through data analysis, calculating the time difference and period effective value of adjacent peak points, and carrying out the real-time identification of the power supply system of the alternating current traction network. And carrying out reliable real-time identification on the power supply system of the AC traction network in combination with a corresponding threshold value. And filtering the original network voltage data by adopting a low-pass filtering mode, and removing components higher than the switching frequency of a four-quadrant rectifier of the traction converter so as to prevent high-frequency components in the network voltage from influencing the identification result of the power supply system of the alternating-current traction network. And continuously calculating the time difference between adjacent peak points of the network voltage for five times, matching the time difference with a normal AC traction network voltage period, preliminarily identifying the power supply system of the AC traction network, and realizing reliable and accurate identification of the power supply system of the traction network in the operation process of the electric locomotive.

Description

Technical Field

[0001] This invention relates to the field of rail transit electrical equipment, and in particular to a method and system for real-time identification of the power supply system of rail transit vehicles and their AC traction networks. Background Technology

[0002] Because the power supply systems of railway traction networks vary from country to country, electric locomotives are required to automatically and in real time identify the traction network power supply system in order to achieve smooth switching between different traction system operating modes and ensure safe and stable operation across networks. For AC traction network power supply systems, the electrical conditions of the traction network are complex and variable, and voltage distortion occurs frequently, especially in sections where the locomotive crosses phase breaks. This can easily trigger ferroresonance in the roof voltage transformer, causing severe distortion of the traction network voltage waveform in a short period of time, posing a significant challenge to the locomotive traction control unit in identifying the traction network power supply system.

[0003] The operating circuit of a certain electric locomotive under an AC traction network (taking AC25kV / 50Hz as an example) is as follows: Figure 1 As shown, when the traction network voltage waveform undergoes severe distortion within a short period, if the locomotive mistakenly determines the traction network power supply mode to be AC15kV / 16.7Hz, the traction system operating mode will switch. Isolating switch QS1 will open, line contactor KM1 will open, and isolating switch QS2 will close. During this process, the locomotive's main circuit breaker is prohibited from closing. After the switch is completed, due to the increased turns ratio of the primary and secondary windings of the traction transformer, the secondary voltage of the traction transformer becomes 5 / 3 of its original value. If the locomotive closes the main circuit breaker and pre-charging contactor KM3 at this time, starting the four-quadrant rectifier, during this process, the line contactor KM1, pre-charging resistor R1, the switching transistors (Q1, Q2, Q3, Q4) of the four-quadrant rectifier, and the intermediate circuit support capacitor C... dc These components will be under overvoltage conditions, which will not only affect their reliability and lifespan, but may even cause component breakdown and damage to surrounding circuits. In addition, due to the locomotive's misjudgment of the traction network power supply system, the locomotive may switch the traction system's operating mode. During this process, it is forbidden to close the main circuit breaker, which may cause the locomotive to have no traction output for a long time. If the locomotive is running in the cross-phase section at this time, it will cause the locomotive to break.

[0004] Currently, locomotive traction control units primarily identify the AC traction network power supply system by extracting characteristic components at 16.7Hz and 50Hz from the network voltage waveform and comparing their effective values ​​to determine the power supply system. However, this method lacks reliability and accuracy. When the traction network voltage waveform is distorted, it can easily produce incorrect identification results, leading to the locomotive incorrectly switching the traction system's operating mode, resulting in serious consequences such as component burnout or locomotive damage.

[0005] In view of this, it is necessary to study a real-time identification method for the power supply system of AC traction network to avoid misidentification of the power supply system of AC traction network and to meet the needs of safe and reliable operation of electric locomotives. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method and system for real-time identification of the power supply system of rail transit vehicles and their AC traction networks, which addresses the shortcomings of the existing technology and enables reliable and accurate identification of the power supply system of the traction network during the operation of electric locomotives.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for real-time identification of the power supply system of an AC traction network, comprising the following steps:

[0008] S1. Collect the secondary grid voltage of the high-voltage inductor and current transformer, and perform low-pass filtering on the collected grid voltage to obtain the raw grid voltage data;

[0009] S2. Filter the network compression data to obtain several network compression data points to be analyzed;

[0010] S3. Filter out the peak points in each network compression data point segment and calculate the time difference between peak points in adjacent time periods;

[0011] S4. If five consecutive time differences are within the first set time range, the traction network power supply system is determined to be AC15kV / 16.7Hz; if five consecutive time differences are within the second set time range, the traction network power supply system is determined to be AC25kV / 50Hz; otherwise, the current network power supply system is determined to be unknown.

[0012] This invention collects the secondary grid voltage of a high-voltage transformer, obtains the raw grid voltage data through low-pass filtering to remove high-frequency components, and then performs data screening. Peak point information is obtained through data analysis, and the time difference and effective value of the period between adjacent peak points are calculated. Combined with appropriate thresholds, the AC traction grid power supply system is reliably identified in real time. Low-pass filtering is used to filter the raw grid voltage data, removing components above the switching frequency of the traction converter's four-quadrant rectifier to prevent high-frequency components in the grid voltage from affecting the identification of the AC traction grid power supply system. The time difference between five consecutive adjacent peak points of the grid voltage is calculated to match the normal AC traction grid voltage period, thus initially identifying the AC traction grid power supply system and achieving reliable and accurate identification of the traction grid power supply system during electric locomotive operation.

[0013] The method of the present invention further includes:

[0014] When the traction power supply system is initially determined to be AC15kV / 16.7Hz or AC25kV / 50Hz, the effective value of the grid voltage within one grid voltage cycle is calculated starting from the moment corresponding to any peak point. If the effective value matches the threshold of the normal grid voltage effective value, the identification result of the traction power supply system is determined to be accurate; otherwise, the current grid voltage system is determined to be unknown.

[0015] In this invention, starting from the time corresponding to the last peak point (t) k+5 Start calculating the effective value of the network voltage within one network voltage cycle.

[0016] From t k From time (the time corresponding to the first peak point) to t k+5 At time (the time corresponding to the last peak point), the period of adjacent peak points is calculated five times consecutively to initially determine the grid voltage power supply system. After the determination is completed, the effective value within a single grid voltage period is calculated. Theoretically, as long as t k ~t k+5 If any time within the specified range is used as the starting time for calculating the effective value, then the action of using the effective value to perform a secondary judgment on the mains voltage power supply system is valid. However, since there are too many mains voltage data points U(n), the locomotive traction control unit (TCU) may not necessarily save t. k ~t k+5 All data points U(n) between these points would occupy storage space. The TCU can discard all network voltage data points U(n) corresponding to a given period after calculating one cycle of adjacent peak points. Therefore, from t... k+5 The optimal choice is to start calculating the effective value of the grid voltage within a grid voltage cycle at any time, which can minimize the occupation of the traction control unit (TCU) storage space.

[0017] Additionally, valid values ​​can also be derived from t. k Real-time calculations are performed at AC15kV / 16.7Hz and AC25kV / 50Hz starting from a specific time. After a preliminary judgment using the period of adjacent peak points, the accuracy of the traction network power supply system identification result is directly determined using the calculated effective value. However, this method has a drawback: real-time calculation of the effective value consumes the computing resources of the locomotive traction control unit (TCU), which may cause a delay in the converter control cycle, affecting the control accuracy and dynamic response, and even causing system instability. Therefore, this invention adopts a method starting from t k+5 The effective value of the grid voltage within a grid voltage cycle is calculated at any time to determine whether the identification result of the traction grid power supply system is accurate, thus avoiding the occupation of computing resources.

[0018] This invention performs secondary identification based on the threshold value of the effective value of the normal AC traction network voltage, further improving the accuracy of AC traction network power supply system identification.

[0019] In this invention, to ensure the safe operation of electric locomotives, when the current grid suppression mode is determined to be unclear, the locomotive main circuit breaker is disconnected without switching the traction system operating mode, and the identification result is transmitted to the locomotive network control system.

[0020] In this invention, when the traction power supply system is determined to be AC15kV / 16.7Hz or AC25kV / 50Hz, the locomotive switches the traction system operating mode, the main circuit breaker is prohibited from closing, and the AC traction power supply system identification result is sent to the locomotive network control system.

[0021] The present invention also includes: displaying the mesh suppression identification results on the driver's cab display screen.

[0022] In this invention, the first set time range is 30~100ms, and the second set time range is 10~29ms.

[0023] As an inventive concept, the present invention also provides a real-time identification system for the power supply mode of an AC traction network, including a memory, a processor, and a computer program stored in the memory; the processor executes the computer program to implement the steps of the above method.

[0024] As an inventive concept, the present invention also provides a rail transit vehicle equipped with the aforementioned identification system.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. This invention adopts a step-by-step screening method, using grid voltage data points after low-pass filtering and data screening. Based on the dual identification of grid voltage period and effective value, it still has high reliability and accuracy when facing severe working conditions such as grid voltage distortion in the over-phase interval. It can avoid incorrect identification of AC traction grid power supply system and ensure the safety of locomotive operation across grids, regions, and countries.

[0027] 2. This invention comprises five steps: raw data acquisition, data filtering, data analysis, AC grid voltage characteristic identification, traction system operating mode switching, and information display. The locomotive traction control unit collects the secondary grid voltage from the high-voltage transformer, and obtains the raw grid voltage data through low-pass filtering to remove high-frequency components. Data filtering is then performed, and peak point information is obtained through data analysis. The time difference and effective value of the period between adjacent peak points are calculated, and the AC traction grid power supply system is reliably identified in real time based on corresponding thresholds.

[0028] 3. This invention uses low-pass filtering to filter the original grid voltage data, removing components above the switching frequency of the traction converter's four-quadrant rectifier, in order to prevent high-frequency components in the grid voltage from affecting the identification of the AC traction grid power supply system.

[0029] 4. This invention continuously calculates the time difference between five adjacent peak points of the grid voltage, matching it with the normal AC traction grid voltage cycle, to initially identify the AC traction grid power supply system. Then, it performs a secondary identification based on the threshold of the effective value of the normal AC traction grid voltage, thereby achieving accurate identification of the AC traction grid power supply system. Attached Figure Description

[0030] Figure 1 A circuit diagram for supplying power to an electric locomotive from an AC traction network.

[0031] Figure 2 This is a flowchart of a method according to an embodiment of the present invention.

[0032] Figure 3 Typical waveform 1 when grid voltage distortion occurs in a 25kV / 50Hz power supply line;

[0033] Figure 4 Typical waveform 2 when grid voltage distortion occurs under a 25kV / 50Hz power supply system. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of 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 some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] This invention discloses a real-time identification method for the power supply system of an AC traction network. This method is based on a step-by-step filtering approach and its core consists of five steps: raw data acquisition, data filtering, data analysis, AC grid voltage characteristic identification, traction system operating mode switching, and information display. The logic diagram is shown below. Figure 2As shown in the diagram. First, the locomotive traction control unit acquires the secondary grid voltage from the high-voltage transformer and performs low-pass filtering to obtain the raw grid voltage data. Second, data filtering is performed, recording a data point every 2ms to obtain the grid voltage data points to be analyzed. Third, data analysis is used to obtain the peak points that meet the requirements. Then, the time difference between adjacent peak points is used to perform a preliminary identification of the AC traction grid power supply system. Next, the effective value of the grid voltage in a single cycle is calculated and compared with a set threshold to perform a secondary identification of the AC traction grid power supply system. Finally, the results are sent to the locomotive network control system and displayed on the driver's cab display screen, while the locomotive switches the traction system operating mode.

[0036] The ease of operation of this invention is reflected in the fact that it is based on basic relational operations, logical operations, and simple arithmetic operations, making it simple to operate. It can be completed using only the existing high-voltage transformers and traction control units on the locomotive, without the need for any additional devices. The high reliability and accuracy of this invention are reflected in the fact that the data analysis process is unaffected by high-frequency interference from the grid voltage. It uses the time difference between adjacent peak points to match the normal AC traction grid voltage cycle for primary identification, and then combines this with the single-cycle effective value of the grid voltage waveform for secondary identification. Even when the grid voltage waveform is severely distorted, the locomotive can accurately identify the AC traction grid power supply system and execute the correct actions.

[0037] Example 1

[0038] Embodiment 1 of the present invention provides a real-time identification method for the power supply system of an AC traction network, which is implemented based on the existing hardware capabilities of the locomotive traction control unit and relies on software algorithms. Figure 2 Here is a logical diagram. The specific steps are as follows:

[0039] Step 1:

[0040] The locomotive traction control unit maintains its existing hardware sampling capabilities, performing high-frequency sampling (10kHz) on the secondary side of the high-voltage transformer, followed by low-pass filtering with a cutoff frequency of 200Hz to obtain the raw grid voltage data. This step involves the sampling circuit, signal conditioning circuit, and chips within the locomotive traction control unit.

[0041] Step Two:

[0042] The locomotive traction control unit performs data filtering on the raw grid voltage data at the software level. When the raw grid voltage data after taking the absolute value is greater than 5kV, the locomotive traction control unit records the data every 2ms to obtain several grid voltage data points U(n) to be analyzed, n=1, 2, ...

[0043] Step 3:

[0044] Analyze the network voltage data, filter out each peak point and its corresponding time according to formula (1), and record them as (x k ,t K (k=1,2……).

[0045] (1)

[0046] Calculate the time difference between adjacent peak points, as shown in formula (2).

[0047] (2)

[0048] Step Four:

[0049] The AC 15kV / 16.7Hz traction power supply system corresponds to a grid voltage frequency and period of 16.7Hz and 60ms, respectively, with an effective value threshold of 11kV~18kV. The AC 25kV / 50Hz traction power supply system corresponds to a grid voltage frequency and period of 50Hz and 20ms, respectively, with an effective value threshold of 17.5kV~29kV. The midpoint between 16.7Hz and 50Hz (33.3Hz) is taken as the critical frequency, and the critical period is 30ms.

[0050] (1) First, the traction network power supply system is initially identified in conjunction with the normal grid voltage cycle:

[0051] 1) When the time difference between adjacent peak points is five consecutive times ( The values ​​are all within 30~100ms, and it is preliminarily determined that the traction network power supply system is AC15kV / 16.7Hz;

[0052] 2) When the time difference between adjacent peak points is within 10~30ms for five consecutive times, it is preliminarily determined that the traction network power supply system is AC25kV / 50Hz;

[0053] 3) Otherwise, the current network suppression method is determined to be unknown.

[0054] (2) Secondly, the traction network power supply system is identified again by combining the normal grid voltage effective value. For example, if the traction network power supply system is initially judged to be AC15kV / 16.7Hz, the grid voltage period is confirmed to be 60ms. Then, according to formula (3), the voltage period is further determined from t. k+5 The effective value (Urms) of the grid voltage is calculated continuously for 60ms and matched with the threshold (11kV~18kV) of the normal grid voltage effective value. If the match is successful, the traction grid power supply system is determined to be AC15kV / 16.7Hz; otherwise, the current grid voltage system is determined to be unknown.

[0055] The determination of AC25kV / 50Hz power supply system is similar.

[0056] (3)

[0057] n is the number of data points, x i Let be the amplitude corresponding to the i-th data point.

[0058] Step 5:

[0059] When the locomotive switches the traction system operating mode, the main circuit components are configured accordingly. During this process, the main circuit breaker is prohibited from closing. Simultaneously, the AC traction network power supply system identification result is sent to the locomotive network control system and displayed on the driver's cab display screen. If the current network power supply system is determined to be unclear in step four, the locomotive main circuit breaker is opened, the traction system operating mode is not switched, and the identification result is sent to the locomotive network control system and displayed on the driver's cab display screen.

[0060] The distorted grid voltage waveforms when entering the phase-splitting region, collected under a certain 25kV / 50Hz power supply system line, are as follows: Figure 3 and Figure 4 As shown. If the existing method is used, the locomotive traction control unit will misjudge, incorrectly identifying the power supply system as 15kV / 16.7Hz. However, by using the invented real-time identification method for the AC traction network power supply system, facing… Figure 3 Based on the grid voltage conditions, it was determined that the traction grid power supply system is 25kV / 50Hz. Figure 4 Based on the voltage status of the power grid, it was determined that the power supply system of the traction network was unclear. The main circuit breaker was not switched and the traction system operating mode was not changed. It can be seen that the present invention has high reliability and accuracy, and ensures the safety of locomotive operation to the greatest extent.

[0061] Example 2

[0062] Embodiment 2 of the present invention provides an identification system corresponding to Embodiment 1 above, including a memory, a processor, and a computer program stored in the memory; the processor executes the computer program in the memory to implement the steps of the method of Embodiment 1 above.

[0063] In some implementations, the memory may be high-speed random access memory (RAM), and may also include non-volatile memory, such as at least one disk storage device.

[0064] In other implementations, the processor can be any type of general-purpose processor, such as a central processing unit (CPU) or a digital signal processor (DSP), and there is no limitation here.

[0065] Example 3

[0066] Embodiment 3 of the present invention provides a rail transit vehicle corresponding to Embodiment 2 above, which is equipped with the identification system of Embodiment 2 above.

[0067] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of this application can be implemented in various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0068] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0069] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0070] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0071] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for real-time identification of the power supply system of an AC traction network, characterized in that, Includes the following steps: S1. Collect the secondary grid voltage of the high-voltage inductor and current transformer, and perform low-pass filtering on the collected grid voltage to obtain the raw grid voltage data; S2. Filter the network compression data to obtain several network compression data points to be analyzed; S3. Filter out the peak points in each network compression data point segment and calculate the time difference between peak points in adjacent time periods; S4. If five consecutive time differences are within the first set time range, the traction network power supply system is determined to be AC15kV / 16.7Hz; if five consecutive time differences are within the second set time range, the traction network power supply system is determined to be AC25kV / 50Hz; otherwise, the current network power supply system is determined to be unknown.

2. The method for real-time identification of power supply system of AC traction network according to claim 1, characterized in that, Also includes: When the traction power supply system is determined to be AC15kV / 16.7Hz or AC25kV / 50Hz, the effective value of the grid voltage within one grid voltage cycle is calculated starting from the time corresponding to any peak point. If the effective value matches the threshold of the normal grid voltage effective value, the identification result of the traction power supply system is determined to be accurate; otherwise, the current grid voltage system is determined to be unknown.

3. The real-time identification method for the power supply system of the AC traction network according to claim 1, as described in claim 2, is characterized in that, The effective value of the network voltage within one network voltage cycle is calculated starting from the moment corresponding to the last peak point.

4. The real-time identification method for the power supply system of the AC traction network according to any one of claims 1 to 3, characterized in that, When the current network suppression mode is determined to be unclear, the locomotive main circuit breaker is disconnected without switching the traction system operating mode, and the identification result is transmitted to the locomotive network control system.

5. The real-time identification method for the power supply system of the AC traction network according to any one of claims 1 to 3, characterized in that, When the traction power supply system is determined to be AC15kV / 16.7Hz or AC25kV / 50Hz, the locomotive switches the traction system operating mode, the main circuit breaker is prohibited from closing, and the AC traction power supply system identification result is sent to the locomotive network control system.

6. The real-time identification method for the power supply system of the AC traction network according to claim 1, characterized in that, Also includes: The results of the mesh suppression identification are displayed on the screen in the driver's cab.

7. The real-time identification method for the power supply system of the AC traction network according to claim 1, characterized in that, The first set time range is 30~100ms, and the second set time range is 10~29ms.

8. A real-time identification system for the power supply mode of an AC traction network, comprising a memory, a processor, and a computer program stored in the memory; characterized in that, The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 7.

9. A rail transit vehicle, characterized in that, It is equipped with the identification system described in claim 8.

Images