Low-speed control method for reconnection DC drive locomotive with complementary traction motor current

Abstract

The present application relates to the field of internal combustion engine vehicle control, and particularly relates to a method for realizing traction motor current complement of low-speed control of double-heading DC transmission locomotive, which comprises the following steps: S10. determining master locomotive and controlled locomotive in two internal combustion engine vehicles adopting double-heading control, and setting the two internal combustion engine vehicles to low-speed control; S20. master locomotive completing traction motor current regulation of master locomotive based on at least motor current given reference value and locomotive speed given reference value; S30. master locomotive determining controlled locomotive motor current given reference value based on at least motor current given reference value and sending controlled locomotive motor current given reference value to controlled locomotive; S40. controlled locomotive completing traction motor current regulation of controlled locomotive based on at least controlled locomotive motor current given reference value to implement power compensation to master locomotive. The present application can satisfy low-speed constant control under double-heading condition of large-tonnage loading and traction background.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of internal combustion engine locomotive control, in particular to a method for realizing low-speed control of a heavy-haul locomotive with complementary traction motor currents. BACKGROUND

[0002] In order to improve the capacity of goods transportation or transloading, large coal mining enterprises need fast quantitative loading systems to realize automatic loading operation. If the locomotive can run smoothly at low speed, the goods can be loaded into the carriage at a certain uniform speed from the conveying point, which can well solve the loading precision, improve the work efficiency and save a lot of manpower and labor intensity. In order to meet the special working methods and needs of users, the applicant adds a low-speed control constant function in the independently developed microcomputer control system.

[0003] With the development and improvement of locomotive manufacturing technology and railway operation capacity, heavy-haul locomotives and large train coal loading and traction have application prospects. With the gradual increase of train load, the traction motor current of the locomotive is also required to increase continuously. Considering the influence of low speed (below 5Km / h) and large current long-time operation on the traction motor, the existing low-speed working condition of the DC main drive shunting type diesel locomotive is suitable for traction of the maximum tonnage of 5000-6500 tons, which cannot meet the loading and traction of the ten-thousand-ton train. In order to adapt to the development of heavy-haul loading and transportation of local railways, it is necessary to develop a low-speed constant control method under double-machine heavy-haul.

[0004] There is a diesel locomotive heavy-haul low constant speed control scheme in the prior art, that is, the master locomotive transmits the target speed, load signal or power reduction percentage signal to the heavy-haul line, and each locomotive individually controls the constant speed according to the instruction speed. However, the execution effect of this scheme is not ideal. Considering the influence of slope, load change and other factors, especially the independent control of the traction motor current of the heavy-haul locomotive, the microcomputer control system of each locomotive will execute real-time tracking and dynamic adjustment of the current size, but due to asynchronization, the dynamic tractions of the two locomotives will interfere with each other. The direct effect is that the two locomotives often collide and vibrate violently.

[0005] Therefore, the prior art still needs to be improved. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application utilizes two direct-current main drive diesel locomotives to adopt recombination control, under the recombination low-speed control working condition, the microcomputer control system of the main control locomotive can well control the loading and unloading and traction of the whole train, through the real-time accurate calculation and fast separate communication transmission of the microcomputer control system, the required compensation motor current signal is transmitted to the microcomputer control system of the controlled locomotive, the controlled locomotive implements power compensation, and the two locomotives synchronously adjust the current and speed. The core parameters of the main generator output current of the two locomotives are uniformly and real-timely commanded by the microcomputer control system of the main control locomotive. The problems that the single low-speed control of the direct-current main drive shunting type diesel locomotive cannot meet the loading and unloading of the super-tonnage vehicle during the loading and traction of the heavy-load train are well solved.

[0007] Specifically, the present application proposes a recombination direct-current drive locomotive low-speed control method for realizing traction motor current complementation, which comprises the following steps: S10. determining a main control locomotive and a controlled locomotive in two diesel locomotives adopting recombination control, and setting the two diesel locomotives to low-speed control; S20. the main control locomotive completing traction motor current regulation of the main control locomotive based on at least a motor current given reference value and a locomotive speed given reference value; S30. the main control locomotive determining a controlled locomotive motor current given reference value based on at least the motor current given reference value and sending the controlled locomotive motor current given reference value to the controlled locomotive; and S40. the controlled locomotive completing traction motor current regulation of the controlled locomotive based on at least the controlled locomotive motor current given reference value to implement power compensation for the main control locomotive.

[0008] In the embodiment of the present application, in step S20, the main control locomotive completing traction motor current regulation of the main control locomotive based on at least a motor current given reference value and a locomotive speed given reference value comprises: S21. determining the motor current given reference value based on a diesel engine speed signal, and comparing the motor current given reference value with a motor current feedback value to obtain a motor current error value; S22. determining the locomotive speed given reference value based on a controller handle position signal, and comparing the locomotive speed given reference value with a locomotive speed feedback value to obtain a locomotive speed error value; and S23. completing traction motor current regulation of the main control locomotive based on the motor current error value and the locomotive speed error value.

[0009] In the embodiment of the present application, in step S23, the traction motor current regulation of the host locomotive based on the motor current error value and the locomotive speed error value comprises: S231. comparing the motor current error value and the locomotive speed error value, and taking the smaller one as the PWM pulse width modulation output of the host locomotive; and S232. controlling the field current of the exciter based on the PWM pulse width modulation output of the host locomotive to control the power output of the main generator of the host locomotive.

[0010] In the embodiment of the present application, in step S30, the host locomotive determines the motor current reference value of the controlled locomotive based on at least the motor current reference value and sends the motor current reference value of the controlled locomotive to the controlled locomotive, which comprises: S31. the host locomotive determines the motor current reference value of the controlled locomotive based on the motor current reference value and the motor current reference compensation parameter of the controlled locomotive; and S32. the host locomotive transmits the motor current reference value of the controlled locomotive to the controlled locomotive through a first network composed of microcomputer boards of the host locomotive and the controlled locomotive at a predetermined period, and the first network is unidirectional.

[0011] In the embodiment of the present application, in step S31, the host locomotive determines the motor current reference value of the controlled locomotive based on the motor current reference value and the motor current reference compensation parameter of the controlled locomotive, which comprises: S311. the host locomotive determines the motor current reference compensation parameter of the controlled locomotive based on the locomotive speed reference value and the locomotive speed feedback value; and

[0012] S312. the host locomotive determines the motor current reference value of the controlled locomotive based on the motor current reference value and the motor current reference compensation parameter of the controlled locomotive.

[0013] In the embodiment of the present application, in step S312, the motor current reference value of the controlled locomotive is determined based on the following equation one:

[0014] Equation one

[0015] wherein I2_ref is the motor current reference value of the controlled locomotive, I1_ref is the motor current reference value, and η is the motor current reference compensation parameter of the controlled locomotive.

[0016] In the embodiment of the present application, in step S311, different values of the motor current reference compensation parameter of the controlled locomotive are determined based on the following equation respectively:

[0017] when η = η1;

[0018] when η = η2;

[0019] When η = η3;

[0020] wherein S1_ref is the locomotive speed given reference value, and S1_fbk is the locomotive speed feedback value.

[0021] In the embodiment of the present application, in S40, the traction motor current regulation of the controlled locomotive based on at least the motor current given reference value of the controlled locomotive to implement power compensation for the master locomotive comprises: S41. receiving the motor current feedback value of the controlled locomotive and comparing the motor current feedback value of the controlled locomotive with the motor current given reference value of the controlled locomotive to obtain a motor current error value of the controlled locomotive; S42. taking the motor current error value of the controlled locomotive as the PWM pulse width modulation output of the controlled locomotive; and S43. controlling the field current of the exciter of the controlled locomotive based on the PWM pulse width modulation output of the controlled locomotive to control the power output of the main generator of the controlled locomotive.

[0022] In the embodiment of the present application, the low-speed control method for the reconnection DC transmission locomotive with complementary traction motor current further comprises the following steps: S50. determining whether to implement the traction no-load control of the controlled locomotive based on the locomotive speed given reference value, the locomotive speed feedback value, and the controlled locomotive speed feedback value or network condition.

[0023] In the embodiment of the present application, in S50, determining whether to implement the traction no-load control of the controlled locomotive based on the locomotive speed given reference value, the locomotive speed feedback value, and the controlled locomotive speed feedback value or network condition comprises:

[0024] S51. when the following equation is satisfied, implementing the traction no-load control of the controlled locomotive after a predetermined time delay:

[0025]

[0026] wherein S1_fbk is the locomotive speed feedback value, and S2_fbk is the controlled locomotive speed feedback value; or

[0027] S52. when a network fault occurs, implementing the traction no-load control of the controlled locomotive after a predetermined time delay,

[0028] wherein the traction no-load control of the controlled locomotive comprises: controlling the PWM pulse width modulation output of the controlled locomotive to be the minimum pulse width, and controlling the exciter field current of the main generator of the controlled locomotive to be the minimum current; and transmitting the over-speed condition to the master locomotive through the second network for alarm.

[0029] The technical scheme of the present application adopts independent and self-developed advanced single-chip microcomputer technology and advanced low-speed control technology concept, and the double-machine reconnection low-speed control technology can control the speed to be stable during loading, and the weight of the goods (for example, coal) loaded in each carriage is error-free under the condition that the upper conveying belt is uniform, and the goods never fall and there is no environmental pollution. Under normal circumstances, the workload of coal mines, ports, marshalling stations and other places is completed by a single locomotive for low-speed control; if heavy load low-speed control traction is required, only two locomotives are needed for reconnection network, without the need for users to purchase new heavy load locomotives at high prices. The technical scheme of the present application solves the needs of users and is welcomed and accepted by users, has high market share, and has great potential in the future market. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 A flowchart of a low-speed control method of a reconnection DC transmission locomotive for realizing complementary traction motor currents is shown.

[0031] Figure 2 A main circuit of a reconnection low-speed control locomotive is shown.

[0032] Figure 3a A software flowchart of a master locomotive is shown.

[0033] Figure 3b A software flowchart of a controlled locomotive is shown. DETAILED DESCRIPTION

[0034] It should be understood that the embodiments of the present application shown in the example embodiments are only illustrative. Although only a few embodiments are described in detail in the present application, those skilled in the art can easily appreciate that various modifications are possible without departing from the teachings of the present application subject matter. Accordingly, all such modifications should be included within the scope of the present application. Other substitutions, modifications, changes and omissions can be made to the design, operating conditions and parameters of the following example embodiments without departing from the spirit of the present application.

[0035] According to the present application, a low-speed control method of a reconnection DC transmission locomotive for realizing complementary traction motor currents is provided, as shown in Figure 1 The method comprises the following steps:

[0036] S10. Determining a master locomotive and a controlled locomotive in two diesel locomotives adopting reconnection control, and setting the two diesel locomotives to low-speed control;

[0037] S20. The master locomotive completes the traction motor current regulation of the master locomotive based on at least the motor current given reference value and the locomotive speed given reference value;

[0038] S30. The main control locomotive determines the controlled locomotive's motor current reference value based at least on the motor current reference value and sends the controlled locomotive's motor current reference value to the controlled locomotive; and

[0039] S40. The controlled locomotive performs traction motor current adjustment based at least on the given reference value of the controlled locomotive motor current to perform power compensation on the main control locomotive.

[0040] In an embodiment of the present invention, in S10, as Figure 2 As shown, when the multiple-unit switch is set to the "Master Control" position, the microcomputer control system of the diesel locomotive detects this input and confirms that this locomotive is the master control locomotive. When the other diesel locomotive sets its multiple-unit switch to the "Controlled" or "Isolated" position, its microcomputer control system detects this input and confirms that this locomotive is the controlled locomotive. When both multiple-unit locomotives' microcomputer control switches are set to the "Low Speed ​​Control" position, the two locomotives perform a joint low-speed control adjustment function.

[0041] In an embodiment of the present invention, in step S10, step S20, where the main control locomotive adjusts the traction motor current of the main control locomotive based at least on a motor current reference value and a locomotive speed reference value, includes: S21. Determining the motor current reference value based on an internal combustion engine speed signal, and comparing the motor current reference value with a motor current feedback value to obtain a motor current error value; S22. Determining the locomotive speed reference value based on a driver's controller handle position signal, and comparing the locomotive speed reference value with a locomotive speed feedback value to obtain a locomotive speed error value; and S23. Adjusting the traction motor current of the main control locomotive based on the motor current error value and the locomotive speed error value.

[0042] In one embodiment, the internal combustion engine includes a diesel engine. The locomotive is equipped with a continuously variable speed control (CVT) handle with five positions: "0, 1, down, hold, up". During normal locomotive traction operation, the handle is used to adjust the diesel engine speed; while in the low-speed control mode of the coupled locomotives, the main locomotive's handle is used to set the "locomotive speed reference value". The microcomputers of the two coupled locomotives automatically maintain the diesel engine speed at 800 rpm in this mode to ensure adequate cooling and ventilation for the traction motors under high current conditions.

[0043] In the low-speed control mode of the coupled locomotive, the microcomputer control system detects the driver's controller handle position. The microcomputer defaults to all three positions (0, 1, and down) as "down," therefore only the "down," "hold," and "up" states are used in this mode. Each time the driver's controller handle moves from the "hold" position to the "up" position, the locomotive's setpoint speed increases by 0.2 km / h; conversely, each time the driver's controller handle moves from the "hold" position to the "down" position, the locomotive's setpoint speed decreases by 0.2 km / h. Therefore, step S22 determines the locomotive speed setpoint value based on the driver's controller handle position signal from the driver's controller handle.

[0044] like Figure 2 As shown, the main control locomotive microcomputer system detects the signals from the shunts SH1~6 as feedback signals for the motor current, and determines the given reference value of the motor current based on the diesel engine speed signal, forming a motor current closed loop; it detects the signal from the speed sensor SG as the locomotive speed feedback signal, and together with the speed given reference value, forms a motor speed closed loop. These two closed-loop adjustments complete the adjustment of the traction motor current of the main control locomotive. The controlled locomotive only serves as a traction force compensation link for the entire train, requiring only one current closed-loop adjustment. The given reference value of the controlled locomotive motor current is transmitted via a fast, separate communication network (the first network described in this application, i.e., ...). Figure 2 2) The communication network transmits data from the main control locomotive to the controlled locomotive. The current feedback signal of the controlled locomotive comes from the signals of the shunts SH1~6 detected by the controlled locomotive itself. Therefore, the core parameters for controlling the output traction current of the main generators of the two locomotives are uniformly and in real time commanded by the microcomputer control system of the main control locomotive; the microcomputer systems of the two locomotives control the excitation current of the exciter by controlling the PWM pulse width modulation output through the CPU, thereby controlling the traction current output of the main generators on the two locomotives, and the two machines are synchronously adjusted.

[0045] In an embodiment of the present invention, step S23, which involves adjusting the traction motor current of the main control locomotive based on the motor current error value and the locomotive speed error value, includes: S231. Comparing the motor current error value with the locomotive speed error value, and taking the smaller of the two as the PWM pulse width modulation output of the main control locomotive; and S232. Controlling the excitation current of the exciter based on the PWM pulse width modulation output of the main control locomotive, so as to control the power output of the main generator of the main control locomotive.

[0046] In the embodiment of the present application, in step S30, the master locomotive determines the controlled locomotive motor current reference value based on at least the motor current reference value and sends the controlled locomotive motor current reference value to the controlled locomotive, which comprises: S31. The master locomotive determines the controlled locomotive motor current reference value based on the motor current reference value and a controlled locomotive motor current reference compensation parameter; and S32. The master locomotive transmits the controlled locomotive motor current reference value to the controlled locomotive through a first network composed of microcomputer boards of the master locomotive and the controlled locomotive alone at a predetermined period, and the first network is unidirectional in sending and receiving. In one embodiment, the predetermined period is 1.5 ms.

[0047] In the embodiment of the present application, in step S31, the master locomotive determines the controlled locomotive motor current reference value based on the motor current reference value and a controlled locomotive motor current reference compensation parameter, which comprises: S311. The master locomotive determines the controlled locomotive motor current reference compensation parameter based on the locomotive speed reference value and the locomotive speed feedback value; and S312. The master locomotive determines the controlled locomotive motor current reference value based on the motor current reference value and the controlled locomotive motor current reference compensation parameter.

[0048] In the embodiment of the present application, in step S312, the controlled locomotive motor current reference value is determined based on the following equation one:

[0049] Equation one

[0050] wherein I2_ref is the controlled locomotive motor current reference value, I1_ref is the motor current reference value, and η is the controlled locomotive motor current reference compensation parameter.

[0051] In the embodiment of the present application, in step S311, different values of the controlled locomotive motor current reference compensation parameter are determined based on the following equations respectively:

[0052] When , η = η1;

[0053] When , η = η2;

[0054] When , η = η3;

[0055] wherein S1_ref is the locomotive speed reference value, and S1_fbk is the locomotive speed feedback value.

[0056] In the embodiment of the present application, in S40, the traction motor current regulation of the controlled locomotive based on at least the controlled locomotive motor current given reference value to implement power compensation for the master locomotive comprises: S41. receiving the controlled locomotive motor current feedback value and comparing the controlled locomotive motor current feedback value with the controlled locomotive motor current given reference value to obtain a controlled locomotive motor current error value; S42. taking the controlled locomotive motor current error value as the PWM pulse width modulation output of the controlled locomotive; and S43. controlling the field current of the field exciter of the controlled locomotive based on the PWM pulse width modulation output of the controlled locomotive to control the main generator power output of the controlled locomotive.

[0057] In the embodiment of the present application, the re-union DC drive locomotive low-speed control method for realizing traction motor current complement further comprises the following steps: S50. determining whether to implement controlled locomotive traction no-load control based on the locomotive speed given reference value, the locomotive speed feedback value and the controlled locomotive speed feedback value or network condition.

[0058] In the embodiment of the present application, in S50, determining whether to implement controlled locomotive traction no-load control based on the locomotive speed given reference value, the locomotive speed feedback value and the controlled locomotive speed feedback value or network condition comprises:

[0059] S51. when the following equation is satisfied, implementing controlled locomotive traction no-load control after a predetermined time delay:

[0060]

[0061] wherein S1_fbk is the locomotive speed feedback value and S2_fbk is the controlled locomotive speed feedback value; or

[0062] S52. when network failure occurs, implementing controlled locomotive traction no-load control after a predetermined time delay,

[0063] wherein the controlled locomotive traction no-load control comprises: controlling the PWM pulse width modulation output of the controlled locomotive to be the minimum pulse width and controlling the field exciter field current of the main generator of the controlled locomotive to be the minimum current; and transmitting the over-speed condition to the master locomotive through the second network (i.e. the communication network 1 in Figure 2

[0064] Reference Figure 2 and Figure 3a , Figure 3b The present application is further described below through a specific embodiment:

[0065] ​1. The microcomputer system uses a reconnection switch and a low-speed control switch to determine the master and slave locomotives for low-speed control. The master locomotive's microcomputer system controls the traction motor current through two closed-loop adjustments: motor current and speed. The slave locomotive's microcomputer control system performs only one closed-loop adjustment of the motor current.

[0066] 2. The microcomputer of the main control locomotive determines the locomotive speed reference value S1_ref by detecting the handle position signal and according to the speed reference subroutine written in the software. The range of the locomotive speed reference value set in this invention is 0.2km / h~10km / h. The microcomputer of the main control locomotive detects the diesel engine speed signal Ne and determines the motor current reference value I1_ref according to the motor current reference subroutine written in the software. The motor current reference value I1_ref and the locomotive speed reference value S1_ref, together with the motor current feedback value I1_fbk and the locomotive speed feedback value S1_fbk, respectively, complete the two closed-loop adjustment functions of the main control locomotive microcomputer.

[0067] 3. The reference value for the controlled locomotive motor current I2_ref is calculated by the main control locomotive microcomputer software based on the main control locomotive motor current reference value I1_ref, the locomotive speed reference value S1_ref, the locomotive speed feedback value S1_fbk, and field application experience. Its equation is as follows:

[0068] Equation 1

[0069] In Equation 1, η is one of the key core parameters of the present invention, serving as the reference compensation parameter for the controlled locomotive motor current. Reasonable parameter values ​​were obtained through multiple experiments at three different stages: η1, η2, and η3, as detailed below:

[0070] when η = η1;

[0071] when η = η2;

[0072] when η = η3;

[0073] Main locomotive The greater the speed difference, the greater η becomes, and the closer the given reference value I2_ref of the controlled locomotive's motor current is to the given reference value I1_ref of the master locomotive's motor current. In other words, the greater the traction force that the controlled locomotive needs to compensate.

[0074] 4. In normal operation, the locomotives use Network 1 communication network to share parameters between the two machines; in the low-speed control mode of the locomotives, the two microcomputer boards that control the current of the traction motors are separately connected to Network 2 communication, referred to as main control board 1 and controlled board 1.

[0075] (1) The communication network 2 sets only one IP address, contains only one parameter I2_ref, and uses one-way sending and receiving, i.e. the master board 1 sends and the controlled board 1 receives.

[0076] (2) The software timer reference is set to 1.5 ms, and every 2 timing periods, i.e. 3 ms, sending (or receiving) is performed once.

[0077] (3) After the controlled board 1 receives the parameter I2_ref, 7 filtering modes are used, the first 2 and the last 2 parameters are removed, and the average value of the middle 3 parameters is taken as the reference value parameter of the controlled locomotive participating in the motor current closed-loop control.

[0078] In actual use, it is found that if the normal 50 ms (or 100 ms) communication period is used, the controlled board 1 receives parameters slowly, and the compensation traction control is not timely; the IP address and parameters sent are too many, resulting in errors and loss of the motor current given reference value I2_ref of the controlled locomotive. The traction motor current of the two locomotives often fluctuates greatly. After using this kind of separate communication network, since the parameter I2_ref transmission is fast and accurate, the controlled locomotive has excellent transient and steady-state performance in compensation traction, and ensures that the whole heavy-haul locomotive is always running in the best state.

[0079] 5. If the following two conditions occur during the operation of the locomotive, the microcomputer system implements traction no-load control. One is that the speed deviation protection value of the two heavy-haul locomotives is set by the software of the controlled locomotive in the low-speed control mode of the heavy-haul locomotive, when , it means that the difference between the speed feedback value S1_fbk of the master locomotive and the speed feedback value S2_fbk of the controlled locomotive is too large, and the locomotive speed is out of synchronization seriously; the second is that if network failure occurs. After a delay of 3 seconds, the microcomputer of the controlled locomotive implements no-load protection: the CPU controls the PWM pulse width modulation output to be the minimum pulse width, and controls the exciter current of the master generator to be the minimum current. Figure 2 At the same time, the overspeed value is sent to the master locomotive microcomputer display screen through network 1 to alarm, and the necessary mechanical connection and speed sensor parts need to be checked.

[0080] 6. Refer to the software flowcharts of Figure 3a and Figure 3b .

[0081] First refer to Figure 3a, which shows the microcomputer software execution of the master locomotive in the reconnection low-speed control mode: after entering the CUP power-on initialization, enter the main program; enter block 2.2 in the main program, first call the analog quantity subprogram: detect and calculate the motor current feedback value I1_fbk; enter block 2.3, call the frequency quantity interrupt subprogram: calculate the locomotive speed feedback value S1_fbk and the diesel engine speed signal value Ne; enter block 2.4, call the motor current given reference subprogram, determine the motor current given reference I1_ref according to the current limiting table written by the software; enter block 2.5, call the speed given subprogram: through the detection of the handle position signal, determine the locomotive speed given reference S1_ref according to the difference value written by the software; enter block 2.6, call the PI regulator subprogram: calculate the output signals of the current and speed closed loops respectively, and then compare them through the comparator (i.e., compare the motor current given reference I1_ref with the motor current feedback value I1_fbk to obtain the motor current error value, compare the locomotive speed given reference S1_ref with the locomotive speed feedback value S1_fbk to obtain the locomotive speed error value, and compare the two error values), and the minimum value after comparison is used as the effective control signal of the PWM pulse width modulation; enter block 2.7, the microcomputer system controls the excitation current of the exciter through the CPU control PWM pulse width modulation output, and then controls the power output of the master locomotive main generator; enter block 2.8, call the controlled locomotive motor current given reference value calculation subprogram, obtain the parameter value of I2_ref; enter block 2.9, call the network 2 sending program, send the parameter I2_ref; enter block 2.10, return to the main program.

[0082] Reference Figure 3b , which shows the microcomputer software execution of the controlled locomotive: after entering the CUP power-on initialization, enter the main program; enter block 2.11 in the main program, first call the analog quantity subprogram: detect and calculate the motor current feedback value I2_fbk; enter block 2.12, call the network 2 communication receiving subprogram: receive the I2_ref parameter value transmitted by the master board 1; enter block 2.13, call the PI regulator subprogram: only need to calculate the output signal of the current closed loop (i.e., compare I2_ref with the motor current feedback value I2_fbk to obtain the difference value), as the effective control signal of the PWM pulse width modulation; enter block 2.14, CPU control PWM pulse width modulation output to control the excitation current of the exciter, and then control the power output of the controlled locomotive main generator; enter block 2.15, return to the main program.

[0083] The technical scheme of the present application adopts independent and self-developed advanced single-chip microcomputer technology and advanced low-speed control technology, and the double-machine heavy connection low-speed control is stable in the loading process, and the weight of each compartment loaded with coal has no error under the uniform speed of the upper conveying belt, and the coal cargo never falls and has no environmental pollution. Under normal circumstances, the workload of coal mines, ports, marshalling stations and other places can be completed by a single locomotive for low-speed control; if heavy load low-speed control traction is needed, only two locomotives in network connection are needed, without the need for users to purchase new high-price heavy-load locomotives. The technical scheme of the present application solves the needs of users, is welcomed and accepted by users, has high market share, and has great potential in the future market.

[0084] The above merely describes the preferred embodiments of the present application, and is not intended to limit the scope of the present application; if the present application is modified or replaced without departing from the spirit and scope of the present application, it should be covered within the protection scope of the claims of the present application.

Claims

1. A low-speed control method for a multiple-unit DC drive locomotive that achieves traction motor current complementarity, characterized in that, The method comprises the following steps: S10. determining a master locomotive and a slave locomotive in two diesel locomotives adopting reconnection control, and setting the two diesel locomotives to low-speed control; S20. the master locomotive completing traction motor current regulation of the master locomotive based on at least a motor current given reference value and a locomotive speed given reference value, which comprises: S21. determining the motor current given reference value based on a diesel engine speed signal, and comparing the motor current given reference value with a motor current feedback value to obtain a motor current error value; S22. determining the locomotive speed given reference value based on a controller handle position signal, and comparing the locomotive speed given reference value with a locomotive speed feedback value to obtain a locomotive speed error value; S23. completing the traction motor current regulation of the master locomotive based on the motor current error value and the locomotive speed error value; S30. the master locomotive determining a slave locomotive motor current given reference value based on at least a motor current given reference value, and sending the slave locomotive motor current given reference value to the slave locomotive, which comprises: S31. the master locomotive determining the slave locomotive motor current given reference value based on the motor current given reference value and a slave locomotive motor current given reference compensation parameter; and S32. transmitting the slave locomotive motor current given reference value to the slave locomotive through a first network composed of microcomputer boards of the master locomotive and the slave locomotive alone at a predetermined period, the first network being unidirectional in sending and receiving; S40. the slave locomotive completing traction motor current regulation of the slave locomotive based on at least the slave locomotive motor current given reference value to implement power compensation for the master locomotive, which comprises: S41. receiving a slave locomotive motor current feedback value, and comparing the slave locomotive motor current feedback value with the slave locomotive motor current given reference value to obtain a slave locomotive motor current error value; S42. taking the slave locomotive motor current error value as a PWM pulse width modulation output of the slave locomotive; S43. controlling field current of an exciter of the slave locomotive based on the PWM pulse width modulation output of the slave locomotive to control main generator power output of the slave locomotive; S50. judging whether to implement slave locomotive traction no-load control based on the locomotive speed given reference value, the locomotive speed feedback value and a slave locomotive speed feedback value or network condition.

2. The method for realizing low speed control of rejoining DC drive locomotive with complementary traction motor current according to claim 1, characterized in that, In step S23, completing the traction motor current regulation of the master locomotive based on the motor current error value and the locomotive speed error value comprises: S231. comparing the motor current error value and the locomotive speed error value, and taking the smaller one as a PWM pulse width modulation output of the master locomotive; and S232. controlling field current of an exciter based on the PWM pulse width modulation output of the master locomotive to control main generator power output of the master locomotive.

3. The method of claim 1, wherein the method further comprises: In step S31, the host locomotive determines the controlled locomotive motor current reference value based on the motor current reference value and the controlled locomotive motor current reference compensation parameter, which includes: S311. determining the controlled locomotive motor current reference compensation parameter based on the locomotive speed reference value and the locomotive speed feedback value; S312. determining the controlled locomotive motor current reference value based on the motor current reference value and the controlled locomotive motor current reference compensation parameter.

4. The method of claim 3, wherein the method further comprises: In step S312, the controlled locomotive motor current reference value is determined based on the following equation: Equation 1 where I2_ref is the controlled locomotive motor current reference value, I1_ref is the motor current reference value, and η is the controlled locomotive motor current reference compensation parameter.

5. The method of claim 4, wherein the method further comprises: In step S311, different values of the controlled locomotive motor current reference compensation parameter are determined based on the following equations, respectively: When , η = η1; When , η = η2; When , η = η3; where S1_ref is the locomotive speed reference value, and S1_fbk is the locomotive speed feedback value.

6. The method of claim 1, wherein the method further comprises: In step S50, whether to implement controlled locomotive traction no-load control is determined based on the locomotive speed reference value, the locomotive speed feedback value, and the controlled locomotive speed feedback value or network condition, which includes: S51. when the following equation is satisfied, the controlled locomotive traction no-load control is implemented after a predetermined time delay: where S1_fbk is the locomotive speed feedback value, and S2_fbk is the controlled locomotive speed feedback value; or S52. when the network fails, the controlled locomotive traction no-load control is implemented after a predetermined time delay, where the controlled locomotive traction no-load control includes: controlling the PWM pulse width modulation output of the controlled locomotive to be the minimum pulse width, and controlling the exciter current of the main generator of the controlled locomotive to be the minimum current; transmitting the overspeed condition to the host locomotive through the second network for alarm.

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