Method of protection against skidding of electric rolling stock with asynchronous traction motors
By determining the target slip speed and limiting torque changes, the method stabilizes traction motor torque, addressing inefficiencies in existing skidding detection methods and ensuring stable traction in electric rolling stock.
Patent Information
- Authority / Receiving Office
- RU · RU
- Patent Type
- Patents
- Current Assignee / Owner
- OBSHCHESTVO S OGRANICHENNOJ OTVETABTVENNOSTJU URALSKIE LOKOMOTIVY
- Filing Date
- 2025-12-24
- Publication Date
- 2026-06-30
AI Technical Summary
Existing methods for detecting and preventing skidding in electric rolling stock with asynchronous traction motors are inefficient due to the inability to account for rapidly changing conditions and result in fluctuations in traction motor torque, leading to increased skidding and loss of traction properties.
Determine the target slip speed of the wheelset, convert the motor shaft angular frequency to peripheral speed, calculate the error between target and measured peripheral speeds, and limit the rate of change of controller torque using a proportional-integral controller with pulse-width modulation to stabilize traction motor torque.
Enhances traction properties by stabilizing torque changes, preventing excessive slippage and maintaining optimal traction under adhesion conditions.
Smart Images
Figure 00000001_ABST
Abstract
Description
[0001] The invention relates to transport technology, in particular to the automation of the traction drive of electric rolling stock with asynchronous traction motors.
[0002] A known method for detecting and preventing skidding of a wheelset of a rail vehicle involves comparing an electrical signal characterizing the operating mode of the wheelset with a specified frequency threshold; if the frequency exceeds this threshold, the occurrence of skidding is judged (Grinevich V. Method for detecting and preventing skidding of a wheelset of a rail vehicle. Russian Federation Patent (RU) 2072670, B60L 3 / 10 1994). To implement the method, the said electrical signal is generated by means of elastic-dissipative elements installed on the wheels of the drive pairs, which significantly complicates the system and reduces its reliability.
[0003] A method for detecting and preventing skidding of a wheel pair of a rail vehicle is known, according to which, when skidding of one or more wheel pairs occurs, the current active electrical powers of the stator windings of asynchronous traction motors are measured, the current temperature of the external environment of the traction section and the current horizontal position of the traction section are measured, the measured values of the temperature of the external environment of the traction section and the horizontal position of the traction section are fed to the inputs of a pre-trained direct propagation artificial neural network, and the value of the depth of the skidding process is obtained from the output, the measured current values of the active electrical powers of the stator windings of asynchronous traction motors and the value of the depth of the skidding process are used to determine the threshold power, the absolute difference of the measured values of the active electrical powers is calculated,the absolute difference in active electrical power is compared with the threshold power and a correction signal is generated to reduce the angular speed of a wheelset moving with excessive slip or the angular speeds of wheelsets moving with excessive slip (Kharisov I.R., Brekson V.V., Limonov D.E., Shatravin K.M., Korobitsyn K.R. Method for preventing skidding of electric rolling stock with asynchronous traction motors. Russian Federation Patent (RU) 2741851, 2020). The disadvantage of this method is the impossibility of early detection of excessive slip processes, due to failure to take into account the rapidly changing conditions that contribute to excessive slip processes.
[0004] The closest in technical essence to the claimed method is the one that sets the traveling speed and the sliding speed, determines the set speed of the wheelset as the sum of the set traveling speed and the sliding speed, calculates the error between the set speed of the wheelset and the measured speed, and determines the set torque based on the error in accordance with the control laws of the PI controller with subsequent limitation of the lower limit of the set torque at the level of the adhesion torque. (Kharisov I.R., Brekson V.V., Limonov D.E., Shatravin K.M., Korobitsyn K.R. Method of protection against skidding of electric rolling stock with asynchronous traction motors. Russian Federation Patent (RU) 2 840 243 C1, 2025). The disadvantage of this method is the lack of limitation of the regulator rate, which entails fluctuations in the traction motor torque, and as a consequence, increased skidding occurs with subsequent loss of traction properties of the electric rolling stock.
[0005] The objective of the invention is to improve the traction properties of electric rolling stock.
[0006] The solution to the problem is achieved by determining the target speed of the electric rolling stock. The target slip speed of the wheelset is determined. The specified peripheral speed of the wheelset is determined as the sum of the target speed of the electric rolling stock and the target slip speed of the wheelset. The current angular frequency of the asynchronous traction motor shaft is measured. The angular frequency of the motor shaft is converted into the peripheral speed of the wheelset. The error between the target peripheral speed of the wheelset and the measured peripheral speed of the wheelset is calculated. Based on the calculated error, the controller torque is determined according to the control laws of a proportional-integral controller. The rate of change of the controller torque is limited, and the limited value of the controller torque is determined as a target for the vector control system with pulse-width modulation.
[0007] The essence of the proposed method for protecting against skidding of electric rolling stock with asynchronous traction motors is explained by the functional diagram of the device shown in Fig. 1, which implements the proposed method using the example of a single-motor asynchronous traction drive.
[0008] According to the invention, the speed target for an electric rolling stock is determined. The peripheral slip speed target for the wheelset is determined. The specified peripheral speed of the wheelset is determined as the sum of the speed target for the electric rolling stock and the peripheral slip speed target for the wheelset. The current angular frequency of rotation of the asynchronous traction motor shaft is measured. The angular frequency of rotation of the motor shaft is converted into the peripheral speed of the wheelset. The error between the specified peripheral speed of the wheelset and the measured peripheral speed of the wheelset is calculated. Based on the calculated error, the controller torque is determined according to the control laws of a proportional-integral controller. The rate of change of the controller torque is limited, and the limited value of the controller torque is determined as a target for a vector control system with pulse-width modulation.
[0009] The driving axles of the vehicle according to Fig. 1 are equipped with a frequency-controlled drive 1 with vector control, containing an asynchronous traction motor 2 and a vector control system with pulse-width modulation 3.
[0010] The anti-slip device comprises a speed setting unit 4, which determines the set speed of the electric rolling stock. The device comprises a slip speed determination unit 5, which determines the set speed of the wheelset slip. The output of the speed setting unit 4 and the output of the slip speed determination unit 5 are connected to the inputs of the set adder unit 6, which determines the set peripheral speed of the wheelset both in the absence of excess slip and in the presence of excess slip. The device comprises a speed sensor 7, which measures the current angular frequency of rotation of the shaft of the asynchronous traction motor 2. The output of the speed sensor 7 is connected to the input of the speed calculation unit 8, which calculates the peripheral speed of the wheelset. The output of the set adder unit 6 is connected to the positive input of the error adder unit 9, and the output of the speed calculation unit 8 is connected to the negative input of the error adder unit 9.The error adder block 9 calculates the difference between the values of the output signals of the setpoint adder block 6 and the speed calculation block 8. The output of the error adder block 9 is connected to the input of the speed controller block 10, which, based on the control law of the proportional-integral speed controller, calculates the controller torque and transmits the calculated value to the intensity setter block 11. The intensity setter block 11 limits the rate of change of the controller torque and determines it as the value of the setpoint torque and transmits the value of the setpoint torque to the vector control system with pulse-width modulation 3.
[0011] The device operates as follows.
[0012] Speed setting unit 4 determines the speed setting for the electric rolling stock and transmits the calculated value to the positive input of setting adder unit 6. Slip speed detection unit 5 determines the slip speed of the wheelset and transmits the calculated value to setting adder unit 6. Setting adder unit 6 determines the set peripheral speed of the wheelset as the sum of the output values of speed setting unit 4 and slip speed detection unit 5, and transmits the calculated value to error adder unit 9. Speed sensor 7 measures the current angular frequency of rotation of the shaft of asynchronous traction motor 2 and transmits the measured value to the input of speed calculation unit 8, which calculates the peripheral speed of the wheelset. Speed calculation unit 8 transmits the calculated value to the negative input of error adder unit 9.The error adder block 9 subtracts the output value of the speed calculation block 8 from the output value of the set adder block 6 and transmits the calculated value to the speed controller block 10. The speed controller block 10 calculates the controller torque based on the control law of the proportional-integral controller and transmits the calculated value to the intensity setter block 11. The intensity setter block 11 limits the rate of change of the controller torque and determines it as the value of the set torque and transmits the value of the set torque to the vector control system with pulse width modulation 3.
[0013] Thus, the proposed method of protection against slipping of electric rolling stock with asynchronous traction allows the maximum possible traction properties to be realized, under adhesion conditions, by limiting the speed of the regulator, which entails a smooth change in the torque of the traction motor and, as a result, increased slippage does not occur.
Claims
A method for preventing skidding of electric rolling stock with asynchronous traction motors, which consists in determining a target speed for the electric rolling stock, determining a target for the peripheral slip speed of the wheelset, calculating the specified peripheral speed of the wheelset as the sum of the target speed for the electric rolling stock and the target for the peripheral slip speed of the wheelset, measuring the current angular frequency of rotation of the shaft of the asynchronous traction motor, converting the angular frequency of rotation of the motor shaft into the peripheral speed of the wheelset, calculating the error between the specified peripheral speed of the wheelset and the measured peripheral speed of the wheelset, and then, on the basis of the calculated error, determining the regulator torque according to the control laws of a proportional-integral regulator, characterized in that the rate of change of the regulator torque is limited,and then the limited value of the controller torque is defined as a task for the vector control system with pulse-width modulation.