A method for controlling medium-pressure return without fire

Abstract

This invention relates to a method for controlling intermediate-voltage power supply without fire, comprising: low-pass filtering the real-time intermediate-voltage value to generate an intermediate voltage value; comparing the intermediate voltage value with a target intermediate-voltage value to generate a voltage deviation value; sending the voltage deviation value to a PI controller to generate an initial target torque value; limiting the initial target torque value to generate the torque value required for intermediate-voltage control; determining the proportional coefficient of the PI controller based on the absolute value of the rate of change of the intermediate-voltage value, and determining the integral coefficient of the PI controller based on the intermediate voltage value, the rate of change of the intermediate-voltage value, and the rate of change of the rate of change of the intermediate-voltage value; calculating the adhesion limiting torque limit based on the currently available adhesion coefficient and the vehicle dynamic load; determining the maximum braking torque limit value of the traction motor based on the adhesion limiting torque limit value and the maximum braking capacity limiting torque value of the traction motor; and limiting the torque value required for intermediate-voltage control by the maximum braking torque limit value to generate the intermediate-voltage control output torque value.

Description

Technical Field

[0001] This invention relates to the field of train technology, and in particular to a method for controlling intermediate pressure during fireless return. Background Technology

[0002] During the testing phase, the trainsets are transported from the factory to the testing site; or during operation, a serious malfunction occurs, resulting in the loss of most traction and rendering the train immobile. In such cases, a locomotive needs to tow the trainset back to its destination. For safety reasons, operations such as raising the pantograph and closing the main circuit breaker are prohibited throughout this process, and the traction system cannot draw current from the grid side. Relying solely on battery power is insufficient to support the long-term operation of the train's monitoring, braking, air conditioning, and lighting systems, affecting not only the comfort of passengers but also reducing operational safety. Therefore, new high-speed and intercity EMUs are required to have a no-fire return function. This means that while being towed, the traction inverter controls the traction motor to operate in a braking-generating mode, converting mechanical energy into electrical energy and transferring it to the intermediate DC link. The auxiliary converter then obtains energy from the intermediate DC link to power the load. The converted and consumed electrical energy in this process must be kept balanced. The load size determines the traction motor output, and the traction inverter must adjust the electric braking force in real time according to the current load size.

[0003] During prolonged periods of unpowered power return, external factors may cause sudden increases or decreases in load, resulting in fluctuations in the controlled medium voltage. When a high-power load suddenly increases, the energy required increases instantaneously, which can easily cause the medium voltage to drop below the undervoltage value, triggering undervoltage protection. When a high-power load suddenly decreases, the energy required decreases instantaneously, which can easily cause the medium voltage to rise sharply above the chopper threshold, causing chopper action or even triggering overvoltage protection, leading to auxiliary shutdown.

[0004] During the no-fire return process, weather conditions such as rain, snow, frost, and fog reduce the available adhesion between the wheel and rail. When the required electric braking force exceeds the available adhesion, the wheel-rail adhesion is broken, and the wheelset slips. At this point, the traction inverter must prioritize anti-slip control, rapidly reducing the electric braking force to restore adhesion. This consumes more energy than it converts, causing the intermediate voltage to drop rapidly and triggering an auxiliary shutdown. Because the wheel-rail adhesion status is unknown, slippage is easily triggered again upon restarting, leading to repeated inverter disconnections.

[0005] There is no solution in the existing technology for how to control the medium pressure when the load change causes medium pressure fluctuations during fireless return, and the medium pressure is rapidly pulled down when anti-slip control is performed by triggering the slide with low adhesion. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for controlling medium pressure during fireless return, thereby ensuring that the medium pressure is controlled within a reasonable range during the fireless return process and improving the stability of the train set during return.

[0007] To achieve the above objectives, the present invention provides a method for controlling medium-pressure return without fire, the method comprising:

[0008] The real-time medium voltage value is low-pass filtered to generate an intermediate voltage value;

[0009] The intermediate voltage value is compared with the target intermediate voltage value to generate a voltage deviation value; the voltage deviation value is sent to the PI controller to generate an initial target torque value; the initial target torque value is subjected to amplitude limiting to generate the torque value required for intermediate voltage control; wherein, the proportional coefficient of the PI controller is determined according to the absolute value of the rate of change of the intermediate voltage value, and the integral coefficient of the PI controller is determined according to the intermediate voltage value, the rate of change of the intermediate voltage value, and the rate of change of the rate of change of the intermediate voltage value.

[0010] Calculate the adhesion limiting torque limit based on the currently available adhesion coefficient and vehicle dynamic load;

[0011] The maximum braking torque limit that the traction motor can currently output is determined based on the adhesion limiting torque limit and the maximum braking capacity limiting torque value of the traction motor.

[0012] The torque value required for medium-pressure control is limited by the maximum braking torque limit value, thereby generating the medium-pressure control output torque value.

[0013] Furthermore, the method also includes:

[0014] If adhesion between the wheel and rail can be reduced, the traction inverter itself can be blocked, and all other traction inverters can be disconnected.

[0015] The minimum adhesion coefficient used by all traction inverters at the coasting moment is selected as the adhesion coefficient available to the wheel and rail after the initial coasting; wherein, the adhesion coefficient currently used is calculated in real time based on the output torque value of the medium-voltage control.

[0016] Based on the adhesion coefficient of the wheel-rail system after the initial coasting, all traction inverters can be restarted.

[0017] The maximum available electrical power value for the load is calculated based on the maximum braking torque limit and the traction motor speed.

[0018] The total available power value of the entire train is calculated based on the maximum available power value of the load and the number of traction inverters in normal operation.

[0019] The load to be started is selected based on the total available electrical power value of the entire train load and the importance of the load.

[0020] Furthermore, the method for generating the rate of change of the intermediate pressure value and the rate of change of the intermediate pressure value is as follows:

[0021] The real-time medium-pressure value is bandpass filtered to generate the medium-pressure value change rate;

[0022] The rate of change of the medium pressure value is bandpass filtered to generate the rate of change of the medium pressure value.

[0023] The bandpass filtering involves first performing low-pass filtering using a low-pass filter, and then performing high-pass filtering using a high-pass filter.

[0024] Furthermore, the proportional coefficient of the PI controller is set in a segmented manner; the segmentation method is to determine the segment interval based on the absolute value of the change rate of the medium pressure value; and the proportional coefficient of the PI controller is positively correlated with the absolute value of the change rate of the medium pressure value.

[0025] Furthermore, the integral coefficient of the PI controller is determined based on the intermediate voltage value, the rate of change of the intermediate voltage value, and the rate of change of the rate of change of the intermediate voltage value, specifically as follows:

[0026] If the intermediate voltage value, the rate of change of the intermediate voltage value, and the rate of change of the intermediate voltage value are all greater than the corresponding set threshold, the integral coefficient of the PI controller is zero.

[0027] Furthermore, the total available power value of the entire train load is calculated based on the maximum available power value and the number of traction inverters in normal operation, specifically including:

[0028] The sum of the maximum available power values ​​of the load sent by each normally operating traction inverter is multiplied by the margin factor.

[0029] Furthermore, if the wheel-rail adhesion can be reduced, the traction inverter itself can be blocked, and all other traction inverters can be disconnected, specifically including:

[0030] Determine whether the available adhesion between the wheel and rail is reduced based on the conditions of shaft acceleration and velocity difference;

[0031] If the adhesion between the wheel and rail can be reduced, the traction inverter itself can be blocked, and the adhesion coefficient used during the coasting moment can be locked.

[0032] The adhesion coefficient and the taxiing flag used at the taxiing moment are sent to the network control system;

[0033] After receiving the coasting flag from any traction inverter, the network control system obtains the current adhesion coefficient from each of the remaining traction inverters and disconnects all traction inverters.

[0034] Furthermore, the adhesion limiting torque limit is calculated based on the currently available adhesion coefficient and the vehicle's dynamic load, using the following specific formula:

[0035]

[0036] Where g is the acceleration due to gravity; D is the wheel diameter; k g η is the gear ratio; g For gear transmission efficiency; m a For axle load, n a For the number of axes, t r For the vehicle's rotational mass, t load The vehicle's dynamic load is represented by μ, which is the currently available adhesion coefficient.

[0037] Furthermore, the step of determining the maximum braking torque limit value that the traction motor can currently output based on the adhesion limiting torque limit value and the maximum braking capacity limiting torque value of the traction motor specifically involves:

[0038] The maximum value between the adhesion limiting torque limit and the maximum braking capacity limiting torque of the traction motor, or the minimum value between the absolute value of the adhesion limiting torque limit and the absolute value of the maximum braking capacity limiting torque of the traction motor, is selected as the current maximum braking torque limit value that the traction motor can output.

[0039] Furthermore, the adhesion coefficient currently being used is calculated in real time based on the output torque value of the medium-pressure control. The specific formula expression is as follows:

[0040]

[0041] Where g is the acceleration due to gravity; D is the wheel diameter; k g η is the gear ratio; g For gear transmission efficiency; m a For axle load, n a For the number of axes, t r For the vehicle's rotational mass, t load For vehicle dynamic load, T cons This is the output torque value for medium-voltage control.

[0042] The present invention provides a medium-pressure control method for fireless return, which real-time corrects the relevant parameters of the proportional-integral (PI) controller by using the real-time value of medium pressure, the rate of change of medium pressure, and the rate of change of the rate of change of medium pressure. This ensures that when the train is running at different speeds during fireless return, or when there are sudden increases or decreases in high-power loads, the medium pressure can be promptly suppressed from dropping or rising, and the medium pressure can be controlled within a reasonable range, thereby improving the stability of the train return. Attached Figure Description

[0043] Figure 1 This is a topology diagram of the high-voltage return line without fire provided in an embodiment of the present invention.

[0044] Figure 2This is one of the flowcharts of the fireless return medium-pressure control method provided in the embodiments of the present invention;

[0045] Figure 3 This is a schematic diagram of the fireless return medium-pressure control strategy provided in an embodiment of the present invention;

[0046] Figure 4 The waveform diagram of the high-speed sudden addition and reduction of high-power load provided in the embodiment of the present invention is shown.

[0047] Figure 5 The waveform diagram of the low-speed sudden increase and decrease of high-power load provided in the embodiment of the present invention is shown.

[0048] Figure 6 This is the second flowchart of the fireless return medium-pressure control method provided in the embodiments of the present invention;

[0049] Figure 7 This is a schematic diagram of the interactive information data flow between the fireless return network control system and the traction system provided in an embodiment of the present invention. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0051] This invention provides a method and system for controlling medium-voltage during no-fire return. By real-time correction of relevant parameters of the PI controller using the real-time value of medium-voltage, the rate of change of medium-voltage value, and the rate of change of the rate of change of medium-voltage value, the system ensures that during no-fire return, when the train operates at different speeds and experiences sudden increases or decreases in high-power loads, the medium-voltage can be promptly suppressed and controlled within a reasonable range. During no-fire return, the traction inverter calculates the current adhesion coefficient and the total available power of the load in real time and interacts with the network control system. When it detects that the available adhesion between the wheel and rail is less than the actual adhesion-triggered coasting, the network control system selectively activates the load based on the total available power of the load and the load's importance, thus avoiding repeated converter disconnection due to reduced adhesion.

[0052] The fireless return medium-voltage control method of the present invention can be used for various types of trains, such as EMUs and electric locomotives. The following embodiments of the fireless return medium-voltage control method are illustrated using EMUs as an example.

[0053] Figure 1 This is a topology diagram of the high-voltage return line without fire provided in an embodiment of the present invention, such as... Figure 1As shown, when the EMU is performing unpowered return, the pantograph is lowered, the main circuit breaker VCB is opened, and the four-quadrant converter is prohibited from operation. The battery contactor KM is closed, and the 110V battery voltage is boosted using a DC / DC boost power module. When the voltage reaches the set value (DC400V / 600V), the traction inverter starts and pre-excites the traction motors M1 and M2, then enters the micro-braking mode. At the same time, the battery contactor KM is opened, and the traction motors feed back energy to charge the support capacitor C. When the control voltage reaches the target value, the auxiliary converter starts, and the load begins to operate normally.

[0054] Figure 2 This is one of the flowcharts of the fireless return medium-pressure control method provided in the embodiments of the present invention, such as... Figure 2 As shown, it includes:

[0055] Step 110: Low-pass filter the real-time medium voltage value to generate an intermediate voltage value.

[0056] Specifically, the real-time medium-voltage value is low-pass filtered, retaining the low-frequency components to obtain an intermediate voltage value with high-frequency components removed, which is used as the medium-voltage control input. Optionally, the cutoff frequency of the low-pass filter can be set to 100Hz.

[0057] Step 120: Compare the intermediate voltage value with the target intermediate voltage value to generate a voltage deviation value; send the voltage deviation value to the PI controller to generate an initial target torque value; perform amplitude limiting processing on the initial target torque value to generate the torque value required for intermediate voltage control; wherein, the proportional coefficient of the PI controller is determined according to the absolute value of the rate of change of the intermediate voltage value, and the integral coefficient of the PI controller is determined according to the intermediate voltage value, the rate of change of the intermediate voltage value, and the rate of change of the rate of change of the intermediate voltage value.

[0058] Specifically, the generation methods for the medium-pressure value change rate and the rate of change of the medium-pressure value change rate are as follows: the real-time medium-pressure value is band-pass filtered to generate the medium-pressure value change rate; the medium-pressure value change rate is band-pass filtered to generate the rate of change of the medium-pressure value change rate.

[0059] The bandpass filtering process involves first applying a low-pass filter, followed by a high-pass filter. The low-pass filter removes high-frequency components, while the high-pass filter performs rate-of-change calculations. Using a high-pass filter instead of a differentiator for rate-of-change calculations effectively reduces the impact of differentiation on noise amplification. Optionally, the cutoff frequency of the low-pass filter is set to 50Hz, and the cutoff frequency of the high-pass filter is set to 5Hz.

[0060] The expression for calculating the initial target torque value is shown in formula (1):

[0061] T nsd (t)=K p *eu (t)+KI*∫e u (t)dt (1)

[0062] Among them, T nsd K is the initial target torque value. p K is the proportional gain of the PI controller. I e is the integral coefficient of the PI controller. u e is the voltage deviation value. u =u dc_f -U dc_set u dc_f U is the intermediate voltage value. dc_set The target medium pressure value is the medium pressure value under four-quadrant control during normal operation, and is a fixed known value.

[0063] In one possible implementation, the proportional coefficient of the PI controller is set in a segmented manner; the segmentation method is to determine the segment interval based on the absolute value of the rate of change of the medium-voltage value; and the proportional coefficient of the PI controller is positively correlated with the absolute value of the rate of change of the medium-voltage value.

[0064] Specifically, when the load suddenly decreases and the medium voltage drops, the rate of change of the medium voltage value is less than 0; when the load suddenly increases and the medium voltage rises sharply, the rate of change of the medium voltage value is greater than 0. The larger the absolute value of the rate of change of the medium voltage value, the greater the power of the sudden load increase or decrease, requiring an increase in the proportional coefficient of the PI controller to improve the response speed and quickly reduce the voltage deviation. When the absolute value of the rate of change of the medium voltage value is small, a relatively small proportional coefficient is used to reduce medium voltage overshoot and improve system stability. The proportional coefficient of the PI controller is set in a segmented manner, ensuring system stability while effectively improving the response speed.

[0065] In a specific example, the proportional coefficient expression of the PI controller is shown in formula (2):

[0066]

[0067] Among them, the absolute value of the rate of change of the medium pressure value |u dc When the PI controller takes values ​​between four different intervals ρ1, ρ2, ρ3, and ρ4, the proportional coefficient can be between γ1 and γ2. 2、 γ 3、 γ 4、 Choose from five different values ​​for γ5.

[0068] It should be noted that the above formula (2) is just an example. The number of interval values ​​and their values ​​can be flexibly set according to the medium pressure control target, and no limitation is made here.

[0069] In one possible implementation, the integral coefficient of the PI controller is determined based on the intermediate voltage value, the rate of change of the intermediate voltage value, and the rate of change of the rate of change of the intermediate voltage value, specifically as follows:

[0070] If the intermediate voltage value, the rate of change of the intermediate voltage value, and the rate of change of the intermediate voltage value are all greater than the corresponding set threshold, the integral coefficient of the PI controller is zero.

[0071] Specifically, when a high-power load is suddenly reduced, the intermediate voltage rises sharply, requiring a rapid reduction in output torque. Since the integral term of the PI controller does not change abruptly, even if the proportional coefficient is increased by the rate of change of the intermediate voltage to offset the integral term, the rate of change gradually decreases as the intermediate voltage rises, causing the proportional coefficient to decrease accordingly. This results in insufficient proportional term to offset the integral term, leading to torque output and a prolonged intermediate voltage overshoot. Therefore, when the intermediate voltage value, the rate of change of the intermediate voltage value, and the rate of change of the intermediate voltage value are all detected to be greater than their respective set thresholds, the integral coefficient of the PI controller is set to 0, effectively clearing the integral term of the PI controller. This ensures that when a rapid increase in the intermediate voltage value is detected, the initial target torque value is quickly reset to 0, preventing an excessively long intermediate voltage overshoot.

[0072] Step 130: Calculate the adhesion limiting torque limit based on the currently available adhesion coefficient and the vehicle dynamic load.

[0073] Specifically, the calculation expression for the adhesion limiting torque limit is shown in formula (3):

[0074]

[0075] Where g is the acceleration due to gravity; D is the wheel diameter; k g η is the gear ratio; g For gear transmission efficiency; m a For axle load, n a For the number of axes, t r For the vehicle's rotational mass, t load The vehicle's dynamic load is represented by μ, which is the currently available adhesion coefficient.

[0076] Step 140: Determine the maximum braking torque limit that the traction motor can currently output based on the adhesion limiting torque limit and the maximum braking capacity limiting torque value of the traction motor.

[0077] Specifically, the maximum value between the adhesion limiting torque limit and the maximum braking capacity limiting torque value of the traction motor, or the minimum value between the absolute value of the adhesion limiting torque limit and the absolute value of the maximum braking capacity limiting torque value of the traction motor, is selected as the current maximum braking torque limit value that the traction motor can output. The maximum braking capacity limiting torque value of the traction motor is a characteristic of the traction motor's braking performance, decreasing with speed at high speeds.

[0078] Step 150: Limit the torque value required for medium-pressure control by the maximum braking torque limit value, and generate the output torque value for medium-pressure control.

[0079] Figure 3 This is a schematic diagram of the fireless return medium-pressure control strategy provided in an embodiment of the present invention, as shown below. Figure 3 As shown, the real-time value of medium pressure u dc After the intermediate voltage value is generated by the low-pass filter, it is compared with the target intermediate voltage value to generate the voltage bias value e. u The signal is fed into the PI controller for proportional-integral conversion; the proportional coefficient K of the PI controller... p and integral coefficient K I From the real-time value of medium pressure u dc , rate of change of medium pressure u dc ′、The rate of change of the medium pressure value u dc "The three numerical values ​​are corrected and, after entering the PI controller for calculation, the initial target torque value T is output." nsd The initial target torque value T nsd After amplitude limiting, the required torque value T for medium-voltage control is output. nsdl Adhesion limiting torque limit T μ The maximum braking capacity limiting torque value T of the traction motor a The generated maximum braking torque limit value T max The required torque value T for medium-pressure control nsdl By applying the maximum limit, the medium-voltage control output torque value T is generated. cons .

[0080] Figure 4 The waveform diagrams for high-speed, sudden-increase and sudden-decrease high-power load tests without fire are provided in this embodiment of the invention. Figure 5 The waveform diagrams for the low-speed sudden increase and decrease of high-power loads provided in the embodiments of the present invention are as follows: Figure 4 and Figure 5 As shown, when a high-power load is suddenly added or removed at high speed and low speed respectively, the intermediate voltage value experiences a short-term drop or rise. After adjusting the PI controller parameters, the intermediate voltage value can return to and be maintained near the target intermediate voltage value in a timely manner.

[0081] In a preferred embodiment, Figure 6 This is the second flowchart of the fireless return medium-pressure control method provided in the embodiments of the present invention, as follows: Figure 6 As shown, after step 150, the following steps are also included:

[0082] Step 210: If the wheel-rail adhesion can be reduced, lock its own traction inverter and disconnect all other traction inverters.

[0083] In one possible implementation, step 210 specifically includes steps A1-A4:

[0084] Step A1: Determine whether the available adhesion between the wheel and rail has decreased based on the shaft acceleration and speed difference conditions.

[0085] Step A2: If wheel-rail adhesion can be reduced, the traction inverter is locked, and the adhesion coefficient used during the slippage is stored. Where wheel-rail adhesion can be reduced and slippage occurs, anti-slip control is required.

[0086] Step A3: Send the adhesion coefficient and the taxiing flag used at the taxiing moment to the network control system.

[0087] Step A4: After receiving the coasting flag from any traction inverter, the network control system obtains the adhesion coefficient currently used by each of the remaining traction inverters and disconnects all traction inverters.

[0088] Figure 7 This is a schematic diagram of the interaction information data flow between the fireless return network control system and the traction system provided in an embodiment of the present invention, as shown below. Figure 7 As shown, the network control system TCMS interacts with multiple traction inverters VVVF1 to VVVFn in real time, including available adhesion coefficient, coasting signal, adhesion coefficient during coasting and available electric braking power, wherein the coasting signal includes a coasting flag.

[0089] Step 220: Select the minimum value of the adhesion coefficients used by all traction inverters at the coasting moment as the adhesion coefficient available to the wheel and rail after the initial coasting; wherein, the adhesion coefficient currently used is calculated in real time based on the output torque value of the medium-voltage control.

[0090] The formula for calculating the adhesion coefficient currently used is shown in equation (4):

[0091]

[0092] Where g is the acceleration due to gravity; D is the wheel diameter; k g η is the gear ratio; g For gear transmission efficiency; m a For axle load, n a For the number of axes, t r For the vehicle's rotational mass, t load For vehicle dynamic load, T cons This is the output torque value for medium-voltage control.

[0093] Step 230: Restart all traction inverters based on the available adhesion coefficient of the wheel and rail after the initial coasting.

[0094] Specifically, auxiliary inverters in high-speed trains typically operate in parallel, with each inverter having the same output power. When one traction inverter detects coasting force reduction, the output power of its corresponding auxiliary inverter remains unchanged, but the intermediate voltage is pulled down until undervoltage occurs, causing an auxiliary shutdown. With the total load unchanged, the output power of other auxiliary inverters increases, leading to increased wheel-rail adhesion. This also causes other inverters to experience coasting force reduction, resulting in further auxiliary shutdowns. Receiving a coasting flag from any traction inverter and disconnecting all traction inverters, reducing the load power to zero, and then restarting can prevent auxiliary shutdowns.

[0095] Step 240: Calculate and generate the maximum available electrical power value for the load based on the maximum braking torque limit and the traction motor speed.

[0096] In one possible implementation, the expression for calculating the maximum available electrical power value of the load is shown in formula (5):

[0097]

[0098] Among them, P a η represents the maximum available electrical power for the load. m For traction motor efficiency; η T For traction inverter efficiency; η A To improve converter efficiency; N m T represents the number of traction motors corresponding to a single traction inverter. max The maximum braking torque limit value, where n is the traction motor speed.

[0099] Step 250: Calculate the total available power value of the entire train load based on the maximum available power value of the load and the number of traction inverters in normal operation.

[0100] In one possible implementation, the total available power value of the entire train load is calculated based on the maximum available power value and the number of traction inverters in normal operation, specifically including:

[0101] The sum of the maximum available power output from each normally operating traction inverter is multiplied by a margin factor. Optionally, the margin factor is 0.75. Including this margin factor improves system stability.

[0102] Step 260: Select the load to be started based on the total available electrical power value of the train's total load and the importance of the load.

[0103] Specifically, when the traction inverter detects coasting again, it returns to steps 210-260 until no coasting occurs. After the train stops or the driver manually resets it, the adhesion coefficient can be restored to its default value. Optionally, the default value is set to 0.16-0.20.

[0104] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0105] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented in hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0106] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A fireless return medium pressure control method, characterized by, The method comprises: Low-pass filtering the medium voltage real-time value to generate an intermediate voltage value; Comparing the intermediate voltage value with a target medium voltage value to generate a voltage deviation value; feeding the voltage deviation value into a PI controller to generate an initial target torque value; and performing amplitude limiting processing on the initial target torque value to generate a medium voltage control required torque value; wherein the proportional coefficient of the PI controller is determined according to the absolute value of the medium voltage rate of change, and the integral coefficient of the PI controller is determined according to the intermediate voltage value, the medium voltage rate of change, and the rate of change of the medium voltage rate of change; Calculating an adhesion limit torque limit value according to the current available adhesion coefficient and the vehicle dynamic load; Determining a braking maximum torque limit value currently outputtable by the traction motor according to the adhesion limit torque limit value and the braking maximum capability limit torque value of the traction motor; Limiting the medium voltage control required torque value by the braking maximum torque limit value to generate a medium voltage control output torque value; The method further comprises: If the available adhesion between the wheel and the rail decreases, locking the traction inverter of the vehicle and cutting off all other traction inverters; Selecting the minimum value of the adhesion coefficients used by all traction inverters at the time of coasting as the adhesion coefficient available after the initial coasting of the wheel and the rail; wherein the current used adhesion coefficient is generated in real time according to the medium voltage control output torque value; Restarting all traction inverters according to the adhesion coefficient available after the initial coasting of the wheel and the rail; Generating a maximum load available electric power value according to the braking maximum torque limit value and the speed of the traction motor; Generating a total load available electric power value of the entire train according to the maximum load available electric power value and the number of normally operating traction inverters; Selecting a load to be started according to the total load available electric power value of the entire train and the importance of the load.

2. The flameless return medium voltage control method of claim 1, wherein, The generation method of the medium voltage rate of change and the rate of change of the medium voltage rate of change is specifically: Band-pass filtering the medium voltage real-time value to generate a medium voltage rate of change; Band-pass filtering the medium voltage rate of change to generate a rate of change of the medium voltage rate of change; The band-pass filtering is low-pass filtering by a low-pass filter first, and then high-pass filtering by a high-pass filter.

3. The flameless return medium voltage control method of claim 1, wherein, The proportional coefficient of the PI controller is set in a segmented manner; the segmented manner is to determine the segmented intervals according to the absolute value of the medium voltage rate of change; and the proportional coefficient of the PI controller is positively correlated with the absolute value of the medium voltage rate of change.

4. The flameless return medium voltage control method of claim 1, wherein, The integral coefficient of the PI controller is determined according to the intermediate voltage value, the medium voltage rate of change, and the rate of change of the medium voltage rate of change, specifically: If the intermediate voltage value, the medium voltage rate of change, and the rate of change of the medium voltage rate of change are all greater than the corresponding set threshold, the integral coefficient of the PI controller is zero.

5. The flameless return medium voltage control method of claim 1, wherein, Generating a total load available electric power value of the entire train according to the maximum load available electric power value and the number of normally operating traction inverters, specifically including: Adding up the maximum load available electric power values sent by each normally operating traction inverter and multiplying the sum by a margin coefficient.

6. The flameless return medium voltage control method of claim 1, wherein, The specific steps of the method of locking the traction inverter of the vehicle and cutting off all other traction inverters if the available adhesion between the wheel and the rail decreases are specifically: Determining whether the available adhesion between the wheel and the rail decreases according to the axle acceleration and the speed difference condition; If the available adhesion between the wheel and the rail decreases, the traction inverter is blocked, and the adhesion coefficient used at the time of coasting is stored; The adhesion coefficient used at the time of coasting and the coasting flag are sent to the network control system; After the network control system receives the coasting flag sent by any traction inverter, the current adhesion coefficient sent by each of the remaining traction inverters is obtained, and all traction inverters are cut off.

7. The flameless return medium voltage control method of claim 1, wherein, The adhesion limit torque limit value is calculated according to the current available adhesion coefficient and the dynamic load of the vehicle, and the specific calculation formula is: wherein is the gravitational acceleration; is the wheel diameter; is the gear ratio; is the gear efficiency; is the axle load, , is the number of axles, is the vehicle rotational mass, is the vehicle dynamic load, is the current available coefficient of friction.

8. The flameless return medium voltage control method of claim 1, wherein, The brake maximum torque limit value currently output by the traction motor is determined according to the adhesion limit torque limit value and the brake maximum capability limit torque value of the traction motor, and the specific formula is: The maximum value of the adhesion limit torque limit value and the brake maximum capability limit torque value of the traction motor, or the minimum value of the absolute value of the adhesion limit torque limit value and the absolute value of the brake maximum capability limit torque value of the traction motor, is selected as the brake maximum torque limit value currently output by the traction motor.

9. The flameless return medium voltage control method of claim 1, wherein, The current adhesion coefficient used is calculated and generated in real time according to the medium-voltage control output torque value, and the specific formula expression is: wherein, is the gravitational acceleration; is the wheel diameter; is the gear ratio; is the gear efficiency; is the axle load, , is the number of axles, is the vehicle rotational mass, is the vehicle dynamic load, is the medium pressure control output torque value.

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