A type of control method, controller, and train capable of varying the traction ratio of the train.

Abstract

This system provides a type of control method, controller, and train capable of varying the traction ratio of the train. It falls under the field of railway transport technology, calculating the initial traction force required to operate the train based on route information, location information, passenger load, rail surface condition, and weather conditions. This traction force is unevenly distributed to each traction unit, and the accumulated working time of each traction unit providing traction is monitored. When the accumulated working time exceeds the set initial time threshold, the traction unit is switched off and another traction unit that is not providing traction is switched on. The traction force is distributed unevenly, and the traction units of different carriages work in rotation according to their accumulated working time, thereby implementing adaptive traction ratio control. Adaptive traction is provided according to actual traction demand, reducing the specific losses and additional energy consumption of the traction system, thus achieving energy savings for the system.

Description

A control method, controller and train with variable drag ratio

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application number 202311371483.1 filed with the State Intellectual Property Office of China on October 20, 2023, entitled “A control method, controller and train for a train with variable drag ratio”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of rail transportation technology, and in particular to a control method, a controller, and a train with a variable drag ratio. Background Art

[0004] Currently, rail transit trains, such as high-speed EMUs, intercity EMUs, urban rail trains, and subway vehicles, generally use a fixed power-to-traction ratio, meaning the ratio remains the same during both off-peak and peak periods. Peak periods see a high number of passengers and heavy loads, while off-peak periods see a low number of passengers and light loads. If the power-to-traction ratio remains the same during off-peak periods, the same power consumption results in wasted electricity. During vehicle operation, most operating conditions require relatively low tractive power. Fixed power-to-traction ratio trains, with high system and auxiliary losses, are detrimental to achieving energy savings. Furthermore, the required power-to-traction ratio varies depending on the line or operating conditions. For example, when operating on subway lines, urban rail trains have short distances between stations, requiring higher acceleration and a higher power-to-traction ratio. However, when operating on intercity lines, where distances between stations are long and speeds are high, a lower power-to-traction ratio can be sufficient. A fixed power-to-traction ratio fails to fully utilize the advantages of urban rail trains.

[0005] Summary of the Invention

[0006] In view of this, the purpose of the present application is to provide a control method, controller and train with a variable drag ratio of a train.

[0007] In a first aspect, an embodiment of the present application provides a method for controlling a train's variable traction ratio, comprising the following steps: obtaining operation information of the train, the operation information including line information, location information, passenger capacity, track surface condition, and weather condition, and calculating a first traction force required for the train operation based on the operation information; distributing the first traction force unevenly to each traction unit, with at least one traction unit not providing traction force; obtaining the accumulated working hours of each traction unit that is providing traction force; comparing the accumulated working hours of each traction unit that is providing traction force with a first time threshold, and in response to the accumulated working hours of the traction unit that is providing traction force being greater than the first time threshold, shutting down the traction unit, resetting the accumulated working hours of the traction unit to zero, and starting another traction unit that is not providing traction force.

[0008] In some embodiments, the method further includes the following steps: calculating the target braking force required for train operation; activating all traction units to participate in electric braking based on the total electric braking force that the train can provide being no greater than the target braking force; and activating at least one traction unit to not participate in electric braking or unequally activating all traction units to participate in electric braking based on the total electric braking force that the train can provide being greater than the target braking force. The unequal activation of all traction units refers to the situation where the electric braking force provided by a traction unit is less than 100% of its maximum electric braking force, for example, a traction unit provides an electric braking force of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, etc., of its maximum electric braking force.

[0009] In some embodiments, distributing the first traction force unevenly to each traction unit includes the step of distributing the first traction force to the least number of traction units that can bear it.

[0010] In some embodiments, distributing the first traction force unevenly to each traction unit includes the following steps: dividing the train control handle level into N level intervals according to the number N of train traction units, and the levels from low to high are the 1st level interval, the 2nd level interval, ..., the Nth level interval, N≥2, N is an integer; the total traction force that the train can provide corresponds to the highest level of the train control handle level, and calculating the first level of the train control handle required for the train operation based on the first traction force; based on the first level falling into the 1st level interval, the first traction force is distributed to 1 traction unit; based on the first level falling into the 2nd level interval, the first traction force is distributed to 2 traction units; ...; based on the first level falling into the Nth level interval, the first traction force is distributed to N traction units.

[0011] In some embodiments, calculating the first traction required for train operation includes the following steps: determining the section in which the train is located, the road condition information of the section, the running direction, and the running speed of the section based on the line information of the train operation and the position information of the train; determining the actual weight of the train based on the passenger capacity and the vehicle's own weight; determining the current adhesion coefficient based on the train's running speed, weather conditions, and track surface conditions; calculating the traction required for the train to operate in the current section or the traction required for the next section based on the road condition information, running direction, actual weight, and adhesion coefficient of the section in which the train is located.

[0012] In some embodiments, all carriages of the train are equipped with a traction control unit and a traction unit, or the train includes a motor car and a trailer car, and the motor car is equipped with a traction control unit and a traction unit.

[0013] In some embodiments, the step is also included: in response to the cumulative working time of the traction unit providing traction being greater than the first time threshold, determining whether the train is in a switchable environment; the switchable environment is a downhill track section or a straight track section.

[0014] In some embodiments, the steps are also included: obtaining the operation information of the train in real time, and calculating the second traction force required for the train operation based on the operation information; judging whether the absolute value of the difference between the second traction force and the first traction force exceeds the second error threshold, and in response to the absolute value of the difference between the second traction force and the first traction force being greater than the second error threshold, replacing the first traction force with the second traction force, and then distributing the first traction force unevenly to each traction unit.

[0015] In the second aspect, an embodiment of the present application provides an on-board controller, 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, the method for controlling the variable drag ratio of a train as described in any of the above embodiments is implemented.

[0016] In a third aspect, an embodiment of the present application provides a rail train, comprising the on-board controller described in the above embodiment.

[0017] The beneficial effects that this application can achieve.

[0018] The present application provides a control method for a train with a variable traction ratio. The method calculates the traction force required for the train operation based on the acquired line information, location information, passenger capacity, track surface condition and weather conditions, distributes the traction force unevenly to each traction unit, and monitors the cumulative working time of each traction unit that is providing traction. Once the cumulative working time is greater than a set first time threshold, the traction unit is turned off and another traction unit that is not providing traction is switched. In the present application, the traction force is unevenly distributed, and the traction units of different carriages are rotated according to the cumulative working time, thereby realizing the control of the variable traction ratio. On the one hand, adaptive traction force is provided according to the actual traction force needs, reducing the traction system's own loss and auxiliary energy consumption, thereby realizing system energy saving. On the other hand, the traction units of different carriages are rotated according to the working time, thereby extending the maintenance interval and service life of the traction units.

[0019] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0021] FIG1 shows a schematic diagram of a 6-carriage rail train configuration according to the present application;

[0022] FIG2 shows a flow chart of a method for controlling a train with a variable drag ratio according to the present application;

[0023] FIG3 shows a first schematic diagram of traction force distribution of a train variable traction ratio control method according to the present application;

[0024] FIG4 shows a second schematic diagram of traction force distribution of a train variable traction ratio control method according to the present application;

[0025] FIG5 shows a third schematic diagram of traction force distribution of a train variable traction ratio control method according to the present application;

[0026] FIG6 shows a flow chart of a control method for a train with a variable drag ratio according to the present application, which includes steps for determining a switching environment.

[0027] Among them: 1-carriage, 2-central control unit, 3-traction control unit, 4-brake control unit, 5-MVB bus, 7-train operation control unit, 8-first car traction control unit, 9-second car traction control unit, 10-third car traction control unit, 11-fourth car traction control unit, 12-fifth car traction control unit, 13-sixth car traction control unit. DETAILED DESCRIPTION

[0028] The term "comprising" in the specification, claims, and drawings of this application is synonymous with "including," "containing," or "characterized by," and is inclusive or open-ended and does not exclude additional unrecited elements or method steps. "Comprising" is a technical term used in claim language to mean that the recited elements are present, but other elements may be added and still form a structure or method within the scope of the claim.

[0029] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and are not to be understood as indicating or implying relative importance. The term "about" in this application is meant to include slight variations (up to + / - 10%) from the stated value.

[0030] In the present application, it has been found that since the traction power required in most working conditions during vehicle operation is relatively small, it is possible to proactively cut off some traction components after making an advance judgment, change the vehicle's power-to-traction ratio, reduce the traction system's own losses and auxiliary energy consumption, and thus achieve system energy saving.

[0031] Based on this, the present application provides a control method for a train with a variable traction ratio, comprising the following steps: obtaining the operating information of the train, the operating information including line information, location information, passenger capacity, track surface condition and weather condition, and calculating the first traction force required for the train operation based on the operating information; distributing the first traction force unevenly to each traction unit, with at least one traction unit not providing traction; obtaining the cumulative working hours of each traction unit that is providing traction; comparing the cumulative working hours of each traction unit that is providing traction with a first time threshold, and in response to the cumulative working hours of the traction unit that is providing traction being greater than the first time threshold, shutting down the traction unit, resetting the cumulative working hours of the traction unit to zero, and starting another traction unit that is not providing traction.

[0032] A method for controlling a train's variable traction ratio is provided in an embodiment of the present application. The method calculates the traction force required for the train's operation based on the acquired line information, location information, passenger capacity, track surface condition, and weather condition of the train, distributes the traction force unevenly to each traction unit, and monitors the accumulated working hours of each traction unit that is providing traction. Once the accumulated working hours are greater than a set first time threshold, the traction unit is shut down and another traction unit that is not providing traction is switched. In the present application, the traction force is unevenly distributed, and the traction units of different carriages are rotated according to the working hours, thereby realizing the control of the variable traction ratio. On the one hand, adaptive traction force is provided according to actual traction force needs, reducing the traction system's own losses and auxiliary energy consumption, thereby realizing system energy saving. On the other hand, the traction units of different carriages are rotated according to the working hours, thereby extending the maintenance interval and service life of the traction units.

[0033] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0034] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0035] The motor-to-trailer ratio is the configuration ratio of the motor vehicle and the trailer vehicle, such as three motor vehicles and three trailer vehicles (3M3T), four motor vehicles and two trailer vehicles (4M2T), five motor vehicles and one trailer vehicle (5M1T), six motor vehicles and zero trailer vehicle (6M0T), etc. It is an important indicator for the configuration of the train's traction power unit. In this application, it has been found that the current rail trains generally have a fixed motor-to-trailer ratio, that is, the motor-to-trailer ratio is the same during low passenger flow and peak passenger flow periods. During peak passenger flow periods, there are many passengers and heavy loads, while during low passenger flow periods, there are few passengers and light loads. If the motor-to-trailer ratio during low passenger flow periods is still the same as that during peak passenger flow periods, the same consumption will result in a waste of electric energy by pulling a light vehicle with great force. During vehicle operation, the traction power required for most working conditions is relatively small, and the system loss and auxiliary loss in fixed motor-to-trailer ratio trains are relatively large, which is not conducive to achieving system energy conservation. In addition, the required power-to-traction ratio configuration varies depending on the line or actual operating conditions of the rail train. For example, when a city train runs on a subway line, the distance between stations is short, and a higher acceleration is required, so a higher power-to-traction ratio configuration is required. When running on an intercity railway, the distance between stations is long, and a higher speed is required. A lower power-to-traction ratio can be configured to meet the train operation needs. A fixed power-to-traction ratio cannot bring out the advantages of a city train.

[0036] The present application provides a rail train with a variable power-traction ratio. In this embodiment, a 6-carriage train is taken as an example. Those skilled in the art will appreciate that the device or method provided in this application can also be applied to trains with other numbers of cars, such as 4 cars, 8 cars, 12 cars, 16 cars, and so on. As shown in FIG1 , in the train configuration of a 6-carriage train, each car 1 is provided with a traction control unit 3 (TCU) and a brake control unit 4 (BCU). The two cars 1 at the head and tail are provided with a central control unit 2 (CCU), a traction control unit 3 (TCU), and a brake control unit 4 (BCU). The central control unit 2, the traction control unit 3, and the brake control unit 4 are all connected to a multi-function vehicle bus (MVB) and are connected via the multi-function vehicle bus (MVB), that is, the central control unit 2, the traction control unit 3, and the brake control unit 4 are connected to the MVB bus 5. The central control unit 2 sends control instructions to the traction control unit 3 and the brake control unit 4 via the MVB bus 5 and receives corresponding status data. The driver's cab is also equipped with a train operation control unit 7, which is also connected to the MVB bus 5. The train operation control unit 7 is connected to the central control unit 2 (CCU) of each carriage through the MVB bus 5 to achieve control of the entire train.

[0037] In some other embodiments, the train operation control unit 7 may also be a module in the central control unit 2 (CCU) where the driver's cab is located, and the train operation control unit 7 realizes the control of the train.

[0038] In this application, the traction converter and traction motor on a train car are collectively referred to as a traction unit. In this embodiment, the six-car train shown in Figure 1 is equipped with six cars, each of which is equipped with a traction control unit 3, a brake control unit 4, and a traction unit. Two central control units 2 are also installed in the front and rear cars. In other embodiments, depending on the maximum traction requirements of the train operation, some of the six cars can be configured as trailers. For example, four of the six cars in a train can be equipped with a traction control unit 3, a brake control unit 4, and a traction unit, while two cars can be configured as trailers.

[0039] The present application provides a method for controlling a train with a variable drag ratio, as shown in FIG2 , comprising the following steps:

[0040] S01: Acquiring train operation information, including line information, location information, passenger capacity, track surface condition, and weather conditions, and calculating a first traction force required for train operation based on the operation information;

[0041] S02: distributing the first traction force unevenly to each traction unit, with at least one traction unit providing no traction force;

[0042] S03: Obtaining the accumulated working time of each traction unit providing traction force;

[0043] S04: Compare the accumulated working time of each traction unit providing traction force with a first time threshold. If the accumulated working time of the traction unit providing traction force is greater than the first time threshold, proceed to step S05; if the accumulated working time of the traction unit providing traction force is not greater than the first time threshold, proceed to step S06.

[0044] Step S05: in response to the accumulated working time of the traction unit currently providing traction being greater than the first time threshold, shutting down the traction unit, recording the working time of the traction unit as 0, and starting another traction unit that is not currently providing traction;

[0045] Step S06: acquiring the train operation information in real time, and calculating the second traction force required for the train operation according to the operation information;

[0046] Step S07: Whether the absolute value of the difference between the second traction force and the first traction force exceeds the second error threshold. If the absolute value of the difference between the second traction force and the first traction force is not greater than the second error threshold, re-enter step S03; if the absolute value of the difference between the second traction force and the first traction force is greater than the second error threshold, replace the first traction force with the second traction force, and then distribute the first traction force unevenly to each traction unit, that is, re-enter step S02.

[0047] In step S01 , the line information is information about the actual line on which the train runs, including the departure station, arrival station, major stations along the way, slope information, curve information, station spacing information, speed limit information, and other information.

[0048] Position information refers to the current position of the train, which can be determined by positioning using an onboard positioning system (such as the GPS global positioning system and the Beidou positioning system) installed on the train. The odometer on the train calculates the mileage of the train by recording the number of wheel revolutions (for example, by sensing the rotation of the wheels through a magnetic sensor or a photoelectric sensor) and multiplying it by its circumference. Since the train track is one-dimensional, the specific position of the train can be determined based on the mileage position of the train on the line. Therefore, mileage can be used as a positioning system for the train. In some embodiments, the train operation control unit or central control unit (CCU) can obtain mileage information sent via the MVB bus from the onboard signal system, and the positioning of the train can be achieved based on a pre-set coordinate mileage model. The coordinate mileage model records the correspondence between the static coordinates of the line to be tested and the track mileage. The static coordinates in the coordinate mileage model are the coordinates of the track of the line to be tested and do not change with the movement of the train. Based on the line information of the train and the position information of the train, the section where the train is located can be determined. The section, for example, a train station section, includes 13 stations, namely station 1, station 2 ... to station 13, which totally includes 12 sections.

[0049] Passenger capacity refers to the real-time number of passengers on a vehicle. In some embodiments, the total weight of passengers in the vehicle can be obtained based on a weight sensor installed at the bottom of the vehicle, thereby estimating the passenger capacity. In some embodiments, the total weight of passengers in the vehicle can be determined based on the difference in weights collected by weight sensors pre-determined for use at the platform, thereby estimating the passenger capacity. In some embodiments, facial recognition can be performed based on images captured by cameras on the platform or in the subway vehicle, and the passenger capacity can be counted and determined.

[0050] Adhesion in the railway system is defined as the maximum traction that can be provided between the wheel and rail while the wheel and rail maintain contact without idling or sliding. Under the action of the axle load, the wheel-rail contact area undergoes elastic deformation, forming an elliptical contact area. When the wheel rolls forward under the action of the driving torque, the wheel-rail material undergoes elastic deformation near the contact area, thereby generating a tangential force on the contact surface to cause the wheel to roll forward. This state of wheel-rail contact with both rolling and sliding is called adhesion. Only when the wheel and rail are in an adhesive state can adhesion be generated, thereby forming the ultimate driving force for the locomotive to move forward. Adhesion formula: F μ =μ×M A ×g,F μis the adhesion force between the wheel and rail, μ is the adhesion coefficient, M A is the total mass of the axle weight and the average load, and g is the acceleration due to gravity.

[0051] The adhesion characteristics of the rail surface directly impact the actual traction and braking force output by the train. The adhesion coefficient μ is influenced by numerous factors, including rail surface conditions, operating speed, wheel / rail material, track gradient, drive mode, curve curvature, axle load, and axle load transfer, and is generally a variable value. Normally, the available adhesion coefficient remains stable when the rail surface is dry. However, in rain, snow, or fog, or when the track is contaminated by fallen leaves or oil, the rail surface becomes slippery, the available adhesion coefficient decreases, and the traction and braking force of the rail vehicle plummets.

[0052] Adhesion utilization rate β is defined as: β=(μ / μ max )×100%, where μ is the adhesion coefficient, μ max The greater the adhesion utilization rate β, the closer the actual adhesion coefficient μ is to the maximum adhesion coefficient μ. max , the adhesion force F between the wheel and rail μ The bigger it is.

[0053] In this application, the calculation of the adhesion coefficient μ is adjusted in real time according to different weather conditions, and the adhesion characteristic curve function expression is used:

[0054] In the formula, μ(V s ) is the train speed V s Adhesion coefficient under V s is the train speed (km / h), and a, b, c, and d are track adhesion parameters. Their values ​​are determined by the track conditions of the current wheelset and are all positive constants. The adhesion characteristic curve parameters for different track conditions under different weather conditions are shown in Table 1.

[0055] Table 1 Parameter values ​​of adhesion characteristic curves for different rail surface conditions.

[0056] A dry rail surface is defined as a dry rail surface; a wet rail surface 1 is defined as a slightly wet rail surface; and a wet rail surface 2 is defined as a rail surface under rainy or snowy conditions. During the calculation process, different rail adhesion condition parameters are set based on the weather conditions and rail surface conditions to obtain the adhesion coefficient for the current rail surface condition. For example, a dry rail surface on a sunny / cloudy day corresponds to a "dry rail surface condition"; a slightly wet rail surface on a sunny / cloudy day corresponds to a "wet rail surface 1"; and a wet rail surface on a rainy / snowy day corresponds to a "wet rail surface 2." In some embodiments, weather conditions and rail surface conditions can be manually determined and input in real time through the train monitoring system (HMI) display screen. This input information can be transmitted to the train operation control unit in real time. In some embodiments, the train operation control unit 7 or the central control unit (CCU) can obtain weather conditions and rail surface conditions from a remote control center via a wireless network. In some embodiments, a machine vision system installed on the train bogie, such as a vision hardware system using a high-speed 3D camera and infrared laser, can also be used to obtain rail surface and weather conditions.

[0057] Generally, the adhesion coefficient is 0.16-0.18 during traction and 0.14-0.16 during braking.

[0058] Calculating the first traction force required for train operation in step S01 includes the following steps:

[0059] S0101: Based on the train's route information and train location information, determine the train's section, road conditions, running direction, and running speed; based on the passenger capacity and vehicle weight, determine the actual train weight m; based on the train's running speed, weather conditions, and track surface conditions, determine the current adhesion coefficient μ;

[0060] S0102: Calculate the traction force for the current train segment based on the train's road condition information, running direction, actual weight, and adhesion coefficient. In some embodiments, the traction force required for the next train segment can also be calculated. Segment road condition information includes, for example, the length of a ramp track segment and the angle θ between the ramp and the horizontal; the length of a curved track segment and the curve radius R.

[0061] (1) If the train is on a straight track section, the traction force required for the train operation is: F = μ × m × g, where m is the actual weight of the train, μ is the adhesion coefficient, and g is the acceleration due to gravity, which is taken as 9.8 m / s 2 .

[0062] (2) If the train is on a downhill slope, the traction force required for the train to operate is:

[0063] When μ×m×g×cosθ is not greater than m×g×sinθ, the minimum traction force required by the train can be 0;

[0064] When μ×m×g×cosθ is greater than m×g×sinθ, the traction force required by the train is F=μ×m×g×cosθ-m×g×sinθ, where θ is the angle between the ramp and the horizontal direction.

[0065] (3) If the train is on an uphill slope track section, the traction force required for the train operation is: F = μ × m × g × cos θ + m × g × sin θ, where θ is the angle between the slope and the horizontal direction.

[0066] (4) If the train is on a curved track section, the traction force required for the train operation is: F = μ × m × g + ω, where ω is the additional resistance of the curve, ω = (A × m × g) / R, where A is a constant between 450 and 800, and R is the curve radius in meters.

[0067] The traction control unit achieves speed regulation by controlling the voltage and frequency of the traction motor, thereby obtaining the torque and speed required by the traction motor for the vehicle. In step S02, the traction force required for train operation is unevenly distributed. In some embodiments, each car is equipped with a traction control unit 3, a brake control unit 4, and a traction unit. As shown in Figure 3, the traction force required for train operation is unevenly distributed to the traction units of each car in a 6-car train. For example, the traction control unit 8 of the first car provides 30% of the traction force required for train operation, the traction control unit 10 of the third car provides 30% of the traction force required for train operation, the traction control unit 13 of the sixth car provides 40% of the traction force required for train operation, and the traction control units of the remaining cars temporarily do not provide traction.

[0068] In some embodiments, for example, as shown in Figure 4, the first car traction control unit 8 provides 25% of the traction required for the train operation, the third car traction control unit 10 provides 25% of the traction required for the train operation, the fourth car traction control unit 11 provides 25% of the traction required for the train operation, the sixth car traction control unit 13 provides 25% of the traction required for the train operation, and the remaining car traction control units temporarily do not provide traction.

[0069] In some embodiments, the train includes motor cars and trailer cars, each of which is equipped with a traction control unit and a traction unit. For example, a train is equipped with four motor cars and two trailer cars, and each of the four motor cars is equipped with a traction control unit 3, a brake control unit 4, and a traction unit. As shown in Figure 5, the traction control unit 8 of the first car provides 50% of the traction required for train operation, the traction control unit 10 of the third car provides 50% of the traction required for train operation, and the traction control units of the remaining cars temporarily do not provide traction.

[0070] In some embodiments of the present application, the first traction force required for train operation is distributed to the minimum number of traction units that can be supported, that is, the minimum number of EMU carriages. If only one traction unit can meet the traction force requirement of the train, the traction unit of one carriage is started first, and then when the cumulative working time of the traction unit is detected to be greater than a first threshold, the traction unit of another carriage is switched, and the different traction units are rotated according to the cumulative working time, thereby realizing variable traction ratio control. In some embodiments, the train operation control unit 7 determines the number of traction units that can be started and the number of traction units that can be shut down based on the traction force required for train operation, selects the traction units of the carriages that can be enabled, and sends a signal to the central control unit 2 of the carriages. The central control unit 2 of the carriages sends a signal to the traction control unit 3 to enable the traction units of the carriages.

[0071] In some embodiments, the number of traction units is determined according to the level of the train control handle. In this application, the first traction force is unevenly distributed to each traction unit, including the steps of:

[0072] S0201: Divide the train control handle level into N level intervals according to the number N of train traction units, where the levels are ranked from low to high as level 1, level 2, ..., level N, where N ≥ 2 and N is an integer;

[0073] S0202: The total traction force that the train can provide is associated with the highest level of the train control handle, and the first level of the train control handle required for train operation is calculated based on the first traction force;

[0074] S0203: According to whether the first level falls into the first level interval, the first traction force is allocated to one traction unit; according to whether the first level falls into the second level interval, the first traction force is allocated to two traction units; ...; according to whether the first level falls into the Nth level interval, the first traction force is allocated to N traction units.

[0075] For example, a train control handle has 100 levels, and the level division step is 100 / N, where N is the number of traction units on the train. For example, a 4-motor, 2-trailer, 6-carriage train. N = 4, meaning the first level interval, including levels 0-25, corresponds to one traction control unit (TCU), the second level interval, including levels 25-50, corresponds to two TCUs, the third level interval, including levels 50-75, corresponds to three TCUs, and the fourth level interval, including levels 75-100, corresponds to four TCUs. TCU selection is based on a first-in, first-out (FIFO) principle. For example, if the traction required for train operation is 200KN, and there is a 6-car train with 4 motor cars and 2 trailer cars, each motor car can provide 150KN of traction, and the total traction provided by the train is 600KN. If 600KN corresponds to the highest level of the train control handle, 100, then the first level of the train control handle required for train operation is (200×100)÷600≈34, and the first level is between levels 25-50, corresponding to two TCUs. The traction can then be distributed to the two motor cars (evenly, for example, 100KN for both motor cars, or unevenly distributed, with one motor car providing 150KN and the other 50KN). The other two motor cars will not provide traction first. When the cumulative operating time of the traction units of the two working motor cars exceeds the first time threshold, the system switches to the traction units of the other two motor cars that are not currently providing traction.

[0076] In step S03, the cumulative operating time of each traction unit providing traction is obtained. The first traction force will change according to the train's operating section, passenger capacity, and adhesion coefficient, and the number of carriages providing traction will also change. During the operation of the train, the cumulative operating time of the traction unit of each carriage will also vary.

[0077] In step S04, the working time of the traction unit of each carriage that is providing traction is compared with a first time threshold. For example, in some embodiments, the first time threshold is set to 2-72h, for example, 2h, 4h, 6h, 8h, 12h, 16h, 20h, 24h, 32h, 36h, 40h, 48h, 56h, 64h, 72h, etc. It is generally determined according to the length of the line to make the use of each traction unit relatively balanced, thereby avoiding a traction unit running for too long.

[0078] The traction unit is switched in step S05. The central control unit 2 or traction control unit 3 of each carriage is provided with a timing unit for the operation of the traction unit. Once the traction unit of the carriage is turned off, the accumulated working time of the carriage is recorded as 0. When the traction unit of the carriage is started again, the timing will be restarted.

[0079] In step S06, the calculation of the tractive force required for train operation in step S01 is repeated. Since the section of the line on which the train runs, the passenger capacity, the adhesion utilization rate, the running speed, and other conditions all change during the operation, the tractive force required for train operation also changes according to different conditions. Therefore, the ratio of the motor car to the trailer car of the train also changes according to the tractive force requirements.

[0080] In step S07, in some embodiments, preferably, the second error threshold may be 0-20 KN, for example, 0, 1 KN, 2 KN, 3 KN, 4 KN, 5 KN, 6 KN, 7 KN, 8 KN, 9 KN, 10 KN, 15 KN, 20 KN, etc.

[0081] In this application, a traction control unit 3 and a braking control unit 4 are provided in the carriage. When the train operation control unit 7 determines that traction is required, it sends a traction instruction to the central control unit 2 via the MVB bus. The central control unit 2 forwards the traction instruction to the traction control unit 3, controlling the traction motor to output the corresponding traction force. When the train operation control unit 7 determines that braking is required, it sends a braking instruction to the central control unit 2 via the MVB bus. The central control unit 2 forwards the braking instruction to the braking control unit 4, controlling the traction motor to perform electric braking and generate the corresponding braking force. By sending a traction instruction or a braking instruction from the train operation control unit 7 to the central control unit 2, the vehicles are controlled to uniformly perform traction or braking actions, which can effectively ensure the consistency of the actions of each motor vehicle in the train, thereby preventing some motor vehicles from being in a traction state while others are in a braking state, preventing irreversible damage to the wheels and rails, and ensuring the safety of train operation.

[0082] In this application, the required traction and electric braking force are calculated in real time based on the line conditions and actual weight, and the number of EMUs required at this time is determined in combination with the line adhesion coefficient. The required traction and electric braking force are then distributed to the traction system of each vehicle according to the imbalance principle. For example, when the system power is low, two of the four EMUs in the 4M2T formation may receive a traction command of 0, and the other two may receive 20% of the maximum traction force of the EMU. When electric braking is performed, the four EMUs simultaneously participate in energy feedback, and at this time the electric braking commands received by the four EMUs are all 100%.

[0083] In some embodiments, a method for controlling a train with a variable traction ratio further includes the steps of: calculating a target braking force required for train operation; activating all traction units to participate in electric braking based on the total electric braking force that the train can provide being no greater than the target braking force; and activating at least one traction unit to not participate in electric braking or unequally activating all traction units to participate in electric braking based on the total electric braking force that the train can provide being greater than the target braking force. The unequal activation of all traction units refers to the situation where the electric braking force provided by a traction unit is less than 100% of its maximum electric braking force, for example, a traction unit provides an electric braking force of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, etc., of its maximum electric braking force. For example, the target braking force required for the vehicle is calculated based on the vehicle's braking parameters. The target braking force can be provided by the vehicle's electric brake and / or air brake, wherein the electric brake is provided by the vehicle's traction system and the air brake is provided by the vehicle's brake system. The maximum electric braking force B that the vehicle's traction units can provide is MAX It is determined by the product of the adhesion coefficient y under braking and the current vehicle mass m, that is, B MAX =y×m. The target braking force can be calculated using the first relationship, which is B R =1.09×p×m; where B R is the braking force requirement of the train, p is the current braking level, and m is the current train mass. Generally, the current braking level P is determined by the level signal output by the signal system. If the rail transit vehicle is in PM (protective manual driving mode) mode, the current braking level is determined by the driver controller signal output by the driver controller. When the total electric braking force that the train can provide is less than or equal to the target braking force, it means that the electric braking force applied by the traction system alone cannot meet the braking force requirement of the vehicle. The traction units of all the EMUs participate in the feedback energy at the same time. At this time, the electric braking instructions received by the four EMUs are all 100%. When the total electric braking force that the train can provide is greater than the target braking force, it means that the traction system can provide electric braking force that meets the braking force requirement of the train. Some EMUs can receive electric braking instructions and participate in electric braking, and the remaining trains do not provide electric braking. If air braking is required to supplement, the remaining braking force is supplemented by air braking, etc. In some embodiments, the sizes of the electric braking commands provided by the motor vehicles may be uneven, for example, the first motor vehicle provides 100% of the maximum electric braking force it can provide, the second motor vehicle provides 100% of the maximum electric braking force it can provide, the third motor vehicle provides 100% of the maximum electric braking force it can provide, and the fourth motor vehicle provides 50% of the maximum electric braking force it can provide.

[0084] In the present application, when a train is running on a line with a slope, the train operation control unit 7 can obtain factors such as the current line section, slope size, running direction, and driving capacity obtained from the traction system based on the obtained train line information and position information, and automatically adjust the traction force required for the train operation according to the passenger capacity and the actual adhesion coefficient of the track surface, and automatically adjust the train's dynamic traction ratio configuration, so that the train can automatically adapt to the line slope, load, driving capacity, etc.

[0085] In some embodiments, as shown in FIG6 , step S08 is further included to determine whether the traction unit of the train is in a switchable environment. If so, step S05 is entered to shut down the traction unit of the carriage, the working time of the traction unit of the carriage is recorded as 0, and the traction unit of another carriage that is not providing traction is started; if it is not in a switchable environment, step S03 is re-entered, and the traction unit of the train continues to run until the train is in a switchable environment. Generally, in order to ensure the safety of train operation, downhill track sections and straight track sections are set as switchable environments, and uphill track sections and curved track sections are non-switchable environments. In this application, the current line section, slope size, whether it is a curved track, and running direction can be obtained based on the obtained train line information and position information, so as to determine whether the train is in a switchable environment.

[0086] The present application provides a control method for a train with a variable traction ratio. The method calculates the traction force required for the train operation based on the acquired line information, location information, passenger capacity, track surface condition and weather conditions, distributes the traction force unevenly to the traction units of each car, and monitors the cumulative working hours of the traction units of each car that is providing traction. Once the cumulative working time is greater than a set first time threshold, the traction unit of the car is turned off and the traction unit of another car that is not providing traction is switched. In the present application, the traction force is unevenly distributed, and the traction units of different cars are rotated according to the working hours, thereby realizing the control of the variable traction ratio. On the one hand, adaptive traction force is provided according to the actual traction force needs, reducing the traction system's own loss and auxiliary energy consumption, thereby realizing system energy saving. On the other hand, the traction units of different cars are rotated according to the working hours, thereby extending the maintenance interval and service life of the traction units.

[0087] In one embodiment, an onboard controller is provided, comprising a memory, a processor, and a computer program stored in the memory and executable by the processor. When the processor executes the computer program, the method for controlling a train with a variable drag ratio described in the above-described embodiments is implemented, such as the process flow shown in Figures 2 and 6 . To avoid repetition, these steps are not described here. Accordingly, an embodiment of the present application provides a rail vehicle, comprising the onboard controller described in the above-described embodiments.

[0088] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the method for controlling the variable drag ratio of a train in the above-mentioned embodiment is implemented, such as the process shown in Figures 2 and 6. To avoid repetition, it is not repeated here.

[0089] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0090] The above is a detailed introduction to the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for those skilled in the art, according to the idea of ​​the present application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A control method for a train with a variable drag ratio, characterized in that: The steps include: Acquiring running information of the train, the running information including line information, location information, passenger capacity, track surface condition and weather condition, and calculating a first traction force required for the train running according to the running information; Distribute the first traction force unevenly to each traction unit, and at least one traction unit does not provide traction force; Obtaining the accumulated working time of each traction unit providing traction force; The accumulated working time of each traction unit that is providing traction force is compared with a first time threshold. In response to the accumulated working time of a traction unit that is providing traction force being greater than the first time threshold, the traction unit is shut down, the accumulated working time of the traction unit is reset to zero, and another traction unit that is not providing traction force is started.

2. A control method for a train variable drag ratio according to claim 1, characterized in that: The method also includes the following steps: calculating the target braking force required for train operation; starting all traction units to participate in electric braking based on the fact that the total electric braking force that the train can provide is not greater than the target braking force; and preventing at least one traction unit from participating in electric braking or starting all traction units unevenly to participate in electric braking based on the fact that the total electric braking force that the train can provide is greater than the target braking force.

3. A control method for a train with variable drag ratio according to claim 1, characterized in that: The non-uniform distribution of the first traction force to each traction unit comprises the step of distributing the first traction force to the least number of traction units that can bear it.

4. A control method for a train with variable drag ratio according to claim 1, characterized in that: The step of non-uniformly distributing the first traction force to each traction unit comprises the following steps: The train control handle level is divided into N level intervals according to the number N of train traction units, and the levels are, from low to high, the first level interval, the second level interval, ..., the Nth level interval, N ≥ 2, and N is an integer; The total traction force that the train can provide corresponds to the highest level of the train control handle, and the first level of the train control handle required for the train operation is calculated according to the first traction force; According to the first level falling into the first level interval, the first traction force is allocated to one traction unit; according to the first level falling into the second level interval, the first traction force is allocated to two traction units; ...; according to the first level falling into the Nth level interval, the first traction force is allocated to N traction units.

5. A control method for a train with variable drag ratio according to claim 1, characterized in that: Calculating the first traction force required for train operation includes the following steps: According to the line information of the train and the location information of the train, determine the section where the train is located, the road condition information of the section, the running direction and the running speed; Determine the actual weight of the train based on the passenger capacity and vehicle weight; Determine the current adhesion coefficient based on the train running speed, weather conditions and track surface conditions; According to the road condition information, running direction, actual weight and adhesion coefficient of the section where the train is located, the traction force required for the train to run in the current section or the traction force required for the next section is calculated.

6. A train variable drag ratio control method according to claim 1, characterized in that: All carriages of the train are equipped with a traction control unit and a traction unit, or the train includes a motor vehicle carriage and a trailer carriage, and all the motor vehicle carriages are equipped with a traction control unit and a traction unit.

7. A control method for a train with variable drag ratio according to claim 1, characterized in that: It also includes the steps of: in response to the cumulative working time of the traction unit providing traction being greater than the first time threshold, determining whether the train is in a switchable environment; the switchable environment is a downhill track section or a straight track section.

8. A train variable drag ratio control method according to claim 1, characterized in that: The method further comprises the steps of: acquiring the running information of the train in real time, and calculating the second traction force required for the running of the train according to the running information; Determine whether the absolute value of the difference between the second traction force and the first traction force exceeds a second error threshold; in response to the absolute value of the difference between the second traction force and the first traction force being greater than the second error threshold, replace the first traction force with the second traction force, and then distribute the first traction force unevenly to each traction unit.

9. A vehicle-mounted controller, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the control method for the variable traction ratio of a train as described in any one of claims 1 to 8 is implemented.

10. A rail train, characterized in that: Includes the vehicle-mounted controller as described in claim 9.