A high-precision constant-speed and force-limiting collaborative control method and system for a motor-driven traction machine

Abstract

This application discloses a high-precision constant speed and force limiting coordinated control method and system for a motor-driven traction machine, relating to the field of power construction equipment. The main control unit calculates the target speed of the permanent magnet synchronous motor based on the target traction speed, the speed ratio of the reducer, and the radius of the traction drum, and sends this calculation to the motor controller. The motor controller performs speed-current dual closed-loop control. Based on the system's total moment of inertia, the motor's dynamics model, and the estimation of the sum of friction torque and external disturbance torque by a third-order extended state observer, the main control unit calculates the real-time traction force and dynamically generates a maximum traction force threshold. When the traction force exceeds the limit, the main control unit sends a torque limiting command to the motor controller, which clamps the q-axis current command to a safe upper limit and freezes the integral term of the PI regulator. When the traction force falls below the threshold, the full PI function is restored. This application achieves high-precision constant speed and safe force limiting control of the traction machine without interrupting traction operations.

Description

Technical Field

[0001] This application relates to the field of power construction equipment technology, and in particular to a high-precision constant speed and force limiting coordinated control method and system for a motor-driven traction machine used for tension stringing. Background Technology

[0002] In the tension stringing construction of high-voltage transmission lines, the core function of the traction machine is to provide and maintain a constant traction speed while ensuring that the output traction force does not exceed the safety threshold.

[0003] Traditional hydraulic traction machines control speed by adjusting hydraulic flow, but their control accuracy is greatly affected by factors such as load fluctuations and oil temperature changes. While motor-driven traction machines have precise control capabilities, they mostly only achieve basic speed control. When the traction force increases sharply due to factors such as terrain and wind resistance, if the output force is not dynamically limited, the excessive traction force may damage the traction rope, wires, or equipment.

[0004] Furthermore, in actual cable-laying operations, due to the enormous mass and inertia of the cable system being pulled, when the traction machine needs to accelerate or decelerate, or when encountering changes in ambient wind speed causing fluctuations in cable tension, it is highly susceptible to mechanical vibration and control oscillations throughout the tensioning system. This dynamic instability not only reduces the quality of the traction operation but may also trigger unnecessary protective actions, severely impacting construction efficiency.

[0005] Therefore, the simple torque limiting or overload shutdown strategies commonly used in existing technologies, although capable of protecting equipment, often lead to interruption of traction operations or significant speed fluctuations, failing to meet the need for safe and smooth limitation of maximum output force without interrupting traction operations. Summary of the Invention

[0006] The purpose of this application is to provide a method and system for high-precision constant speed and force limiting coordinated control of a motor-driven traction machine, which can realize high-precision constant speed operation of the motor-driven traction machine and safely and smoothly limit the maximum output force without interrupting the traction operation.

[0007] To achieve the above objectives, this application provides the following solution.

[0008] In a first aspect, this application provides a high-precision constant speed and force limiting coordinated control method for a motor-driven traction machine. The method includes: a main control unit calculating the target rotational speed of the traction drum based on the target traction speed of the guide rope and the radius of the traction drum; converting the target rotational speed of the traction drum into the target rotational speed of the permanent magnet synchronous motor based on the speed ratio of the reducer; and sending this conversion to the motor controller; the motor controller performs speed-current dual closed-loop control, acquiring the real-time rotational speed of the permanent magnet synchronous motor through a rotary transformer embedded in the motor, acquiring the three-phase current of the permanent magnet synchronous motor through a current sensor embedded in the motor controller, calculating the q-axis current through coordinate transformation, calculating the error between the real-time rotational speed and the target rotational speed of the permanent magnet synchronous motor, and inputting this error into the speed outer loop PI regulator to generate q... The main control unit obtains the real-time speed and q-axis current of the permanent magnet synchronous motor from the motor controller, and calculates the real-time output torque and real-time traction force of the permanent magnet synchronous motor based on the motor dynamics model. The main control unit estimates the sum of friction torque and external disturbance torque online through a third-order extended state observer, and dynamically generates the maximum traction force threshold. The main control unit determines whether the real-time traction force exceeds the maximum traction force threshold. If so, the main control unit sends a torque limiting command to the motor controller, and the motor controller clamps the q-axis current command to the safe upper limit value, while freezing the integral term accumulation of the current inner loop PI regulator. When the real-time traction force is lower than the maximum traction force threshold, the motor controller releases the clamping limit of the q-axis current command and resumes the normal accumulation of the integral term. If not, the motor controller continues to execute the complete speed-current dual closed-loop control.

[0009] Secondly, this application also provides a high-precision constant speed and force limiting coordinated control system for a motor-driven traction machine. The system includes: a rotary transformer mounted on the shaft of a permanent magnet synchronous motor (PMSM) for acquiring the real-time speed of the PMSM; a current sensor integrated in the motor controller for acquiring the three-phase current of the PMSM; a main control unit, acting as a host computer, communicating with the motor controller via a CAN bus to calculate the target speed of the traction drum based on the target traction speed of the guide rope and the radius of the traction drum, and converting the target speed of the traction drum into the target speed of the PMSM based on the speed ratio of the reducer before sending it to the motor controller; obtaining the real-time speed and q-axis current of the PMSM from the motor controller, and calculating the real-time output torque and real-time traction force of the PMSM based on the motor dynamics model; and observing the third-order extended state. The system estimates the sum of friction torque and external disturbance torque online and dynamically generates a maximum traction force threshold. It then determines whether the real-time traction force exceeds the maximum traction force threshold. When the real-time traction force exceeds the maximum traction force threshold, it sends a torque limiting command to the motor controller. The motor controller, used to execute speed-current dual closed-loop control, calculates the q-axis current through coordinate transformation, calculates the error between the real-time speed of the permanent magnet synchronous motor and the target speed of the permanent magnet synchronous motor, and inputs the speed outer loop PI regulator to generate the q-axis current command. When the real-time traction force exceeds the maximum traction force threshold, it receives the torque limiting command sent by the main control unit, clamps the q-axis current command to a safe upper limit, and freezes the integral term accumulation of the current inner loop PI regulator. When the real-time traction force is lower than the maximum traction force threshold, the motor controller releases the clamping limitation of the q-axis current command and restores the normal accumulation of the integral term, continuing to execute the complete speed-current dual closed-loop control.

[0010] Based on the specific embodiments provided in this application, the following technical effects are disclosed.

[0011] This application constructs a three-level closed-loop control system of "speed-current-force" through the collaboration of the main control unit and the motor controller. Based on a precise motor dynamics model and a third-order extended state observer, the main control unit achieves online compensation for friction and disturbances, ensuring the accuracy of traction force calculation. When the traction force exceeds the limit, it dynamically clamps the q-axis current command and freezes the PI integral term, achieving safe force limiting without interrupting traction operations. This scheme not only ensures high-precision stability of traction speed but also avoids construction interruptions caused by traditional overload shutdowns, significantly improving the continuity, safety, and reliability of the traction machine's operation. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a flowchart of a high-precision constant speed and force limiting coordinated control method for a motor-driven traction machine in one embodiment of this application.

[0014] Figure 2 This is a schematic diagram of the structure of a high-precision constant speed and force limiting coordinated control system for a motor-driven traction machine, as shown in another embodiment of this application.

[0015] Reference numerals: Rotary transformer-1, current sensor-2, main control unit-3, motor controller-4, permanent magnet synchronous motor-5. Detailed Implementation

[0016] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0017] In existing traction machine control operations, as described in CN114740821B, a "remote centralized control system for synchronous operation of multiple tension machines and traction machines" has been proposed. This system uses a "central control console" to uniformly command multiple devices, achieving centralized control at a macro level and enabling one person to operate multiple machines. However, this solution focuses on the synchronization of commands between devices and does not solve the control problem of how to protect the equipment and maintain the traction speed when a single traction machine encounters steep slopes, strong winds, or other conditions that cause a sharp increase in traction force. Therefore, developing a control method that can achieve high-precision constant speed operation and safely and smoothly limit the maximum output force without interrupting traction operations is of great significance for improving the performance, efficiency, and safety of motor-driven traction machines.

[0018] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] In one exemplary embodiment, a high-precision constant speed and force limiting coordinated control method for a motor-driven traction machine is provided, such as... Figure 1 As shown, the high-precision constant speed and force limiting coordinated control method of the motor-driven traction machine includes the following steps.

[0020] Step S1: The main control unit calculates the target rotational speed of the traction drum based on the target traction speed of the guide rope (or wire) and the radius of the traction drum. Then, based on the speed ratio of the reducer, the target rotational speed of the traction drum is converted into the target rotational speed of the permanent magnet synchronous motor and sent to the motor controller (via CAN bus).

[0021] In this embodiment, the formula for calculating the target rotational speed of the traction drum is as follows.

[0022] .

[0023] .

[0024] In the formula, The target value for the traction speed of the guide rope / conductor; r The radius of the traction drum; The target rotational speed of the traction drum.

[0025] The main control unit converts the target speed of the traction drum into the target speed of the permanent magnet synchronous motor based on the speed ratio of the reducer. The calculation formula is as follows.

[0026] .

[0027] In the formula, The target speed of the permanent magnet synchronous motor; i The speed ratio of the reducer is given and sent to the motor controller via the CAN bus.

[0028] Step S2: The motor controller performs speed-current dual closed-loop control. It collects the real-time speed of the permanent magnet synchronous motor through the rotary transformer (embedded in the permanent magnet synchronous motor), collects the three-phase current of the permanent magnet synchronous motor through the current sensor embedded in the motor controller, calculates the q-axis current through coordinate transformation, calculates the error between the real-time speed of the permanent magnet synchronous motor and the target speed of the permanent magnet synchronous motor, and inputs the speed outer loop PI regulator to generate the q-axis current command.

[0029] Step S3: The main control unit (via CAN bus) obtains the real-time speed and q-axis current of the permanent magnet synchronous motor from the motor controller, and calculates the real-time output torque and real-time traction force of the permanent magnet synchronous motor based on the motor dynamics model.

[0030] In this embodiment, the expression for the motor dynamics model is as follows.

[0031] .

[0032] In the formula, F For real-time traction force; This refers to the real-time output torque of the permanent magnet synchronous motor. The total moment of inertia of the system; The speed change rate of the permanent magnet synchronous motor; It is the sum of friction torque and external disturbance torque.

[0033] The formula for calculating the real-time output torque of a permanent magnet synchronous motor based on the motor dynamics model is as follows.

[0034] .

[0035] In the formula, is the torque constant of the permanent magnet synchronous motor; This represents the q-axis current of the permanent magnet synchronous motor.

[0036] Step S4: The main control unit estimates the sum of friction torque and external disturbance torque online through a third-order extended state observer, and dynamically generates the maximum traction force threshold.

[0037] In this embodiment, the state equation of the third-order extended state observer is as follows.

[0038] .

[0039] In the formula, , and For observer state variables; , and The first derivative of the observer's state variable with respect to time; , and The observer gain coefficient; The real-time rotational speed of the permanent magnet synchronous motor; the third-order extended state observer sums the frictional torque and the external disturbance torque. Estimated as an expansion state T interference = · .

[0040] The formula for calculating the maximum traction force threshold is as follows.

[0041] .

[0042] In the formula, The maximum traction force threshold; This is the safety margin coefficient, with a value range of [1.1, 1.5]. This is the exponentially smoothed value of the traction force. The calculation formula is as follows.

[0043] .

[0044] In the formula, The real-time traction force for the current control cycle; α This is a smoothing coefficient, with a value range of [0.7, 0.99]. This is the exponentially smoothed value from the previous control period.

[0045] Step S5: The main control unit determines whether the real-time traction force exceeds the maximum traction force threshold.

[0046] Step S6: If yes, the main control unit sends a torque limiting command to the motor controller. The motor controller clamps the q-axis current command to the safe upper limit value and freezes the integral term accumulation of the current inner loop PI regulator. When the real-time traction force is lower than the maximum traction force threshold, the motor controller releases the clamping limit of the q-axis current command and resumes the normal accumulation of the integral term.

[0047] In this embodiment, the formula for calculating the safety upper limit is as follows.

[0048] .

[0049] In the formula, This is the upper limit for safety.

[0050] The integral term accumulation of the inner loop PI regulator is frozen. Specifically, when a torque limiting command is detected, the motor controller suspends the updating of the integral term, keeping the integral term unchanged at its current value until the limiting is lifted.

[0051] Step S7: If not, the motor controller continues to execute the complete speed-current dual closed-loop control.

[0052] In another exemplary embodiment, a high-precision constant speed and force limiting coordinated control system for a motor-driven traction machine is provided, such as... Figure 2 As shown, the system includes the following components.

[0053] Rotary transformer 1 is installed on the shaft of permanent magnet synchronous motor 5 and is used to collect the real-time speed of permanent magnet synchronous motor 5.

[0054] The current sensor 2, integrated in the motor controller 4, is used to collect the three-phase current of the permanent magnet synchronous motor 5.

[0055] The main control unit 3, acting as a host computer, communicates with the motor controller 4 via the CAN bus. It calculates the target rotational speed of the traction drum based on the target traction speed of the guide rope and the radius of the traction drum. Then, based on the speed ratio of the reducer, it converts the target rotational speed of the traction drum into the target rotational speed of the permanent magnet synchronous motor 5 and sends it to the motor controller 4 (via the CAN bus). It also obtains the real-time rotational speed and q-axis current of the permanent magnet synchronous motor 5 from the motor controller 4 (via the CAN bus) and calculates the real-time output torque and real-time traction force of the permanent magnet synchronous motor 5 based on the motor dynamics model. Furthermore, it estimates the sum of frictional torque and external disturbance torque online using a third-order extended state observer and dynamically generates a maximum traction force threshold. It then determines whether the real-time traction force exceeds the maximum traction force threshold. When the real-time traction force exceeds the maximum traction force threshold, it sends a torque limiting command to the motor controller 4.

[0056] Motor controller 4 is used to perform speed-current dual closed-loop control. It calculates the q-axis current through coordinate transformation, calculates the error between the real-time speed of permanent magnet synchronous motor 5 and the target speed of permanent magnet synchronous motor 5, and inputs the speed outer loop PI regulator to generate the q-axis current command. When the real-time traction force exceeds the maximum traction force threshold, it receives the torque limiting command sent by the main control unit 3, clamps the q-axis current command to the safe upper limit value, and freezes the integral term accumulation of the current inner loop PI regulator. When the real-time traction force is lower than the maximum traction force threshold, motor controller 4 releases the clamping limit of the q-axis current command and restores the normal accumulation of the integral term, and continues to execute the complete speed-current dual closed-loop control.

[0057] In one preferred embodiment, the main control unit 3 specifically includes the following modules.

[0058] The traction calculation module is used to calculate the real-time output torque and real-time traction force of the permanent magnet synchronous motor based on the motor dynamics model.

[0059] The state observer module is used to estimate the sum of friction torque and external disturbance torque online through a third-order extended state observer, and dynamically generate the maximum traction force threshold.

[0060] The force limiting judgment module is used to determine whether the real-time traction force exceeds the maximum traction force threshold, and sends a torque limiting command to the motor controller when the real-time traction force exceeds the maximum traction force threshold.

[0061] The system also includes: a human-machine interface for setting the target traction speed of the guide rope; and a communication interface for receiving traction speed commands sent by an external control system.

[0062] In summary, this application has the following significant beneficial effects.

[0063] (1) High control precision: Through the three-level closed loop of "speed-current-force", high-precision control of traction speed is achieved.

[0064] (2) High safety: By monitoring the traction force in real time and limiting the torque, it effectively prevents equipment damage and safety accidents caused by overload. At the same time, by dynamically generating the maximum traction force threshold, it avoids overload damage.

[0065] (3) Good construction continuity: During the force limiting process, the speed stability is prioritized to avoid sudden shutdown, thus ensuring the continuity and efficiency of construction.

[0066] (4) High stability: It achieves coordinated control of "constant speed" and "limited force", and the two work together to make the equipment operation more stable and reliable. In addition, by introducing an anti-integral saturation strategy and an expansion state observer, this invention effectively suppresses system oscillations caused by large inertia conditions, ensuring the smooth operation of the entire tensioning system.

[0067] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0068] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A high-precision constant speed and force limiting coordinated control method for a motor-driven traction machine, characterized in that, The high-precision constant speed and force limiting coordinated control method for the motor-driven traction machine includes: The main control unit calculates the target rotational speed of the traction drum based on the target value of the traction speed of the guide rope and the radius of the traction drum, and converts the target rotational speed of the traction drum into the target rotational speed of the permanent magnet synchronous motor according to the speed ratio of the reducer before sending it to the motor controller. The motor controller performs speed-current dual closed-loop control. It collects the real-time speed of the permanent magnet synchronous motor through the rotary transformer embedded in the permanent magnet synchronous motor, and collects the three-phase current of the permanent magnet synchronous motor through the current sensor embedded in the motor controller. The q-axis current is calculated through coordinate transformation. The error between the real-time speed of the permanent magnet synchronous motor and the target speed of the permanent magnet synchronous motor is calculated and input to the speed outer loop PI regulator to generate the q-axis current command. The main control unit obtains the real-time speed and q-axis current of the permanent magnet synchronous motor from the motor controller, and calculates the real-time output torque and real-time traction force of the permanent magnet synchronous motor based on the motor dynamics model. The main control unit estimates the sum of friction torque and external disturbance torque online through a third-order extended state observer and dynamically generates the maximum traction force threshold. The main control unit determines whether the real-time traction force exceeds the maximum traction force threshold; If so, the main control unit sends a torque limiting command to the motor controller, and the motor controller clamps the q-axis current command to the safe upper limit value, while freezing the integral term accumulation of the current inner loop PI regulator; when the real-time traction force is lower than the maximum traction force threshold, the motor controller releases the clamping limit of the q-axis current command and resumes the normal accumulation of the integral term. If not, the motor controller continues to execute complete speed-current dual closed-loop control.

2. The high-precision constant speed and force limiting coordinated control method for a motor-driven traction machine according to claim 1, characterized in that, The state equation of the third-order extended state observer is: ； In the formula, , and For observer state variables; , and The first derivative of the observer's state variable with respect to time; , and The observer gain coefficient; This refers to the real-time output torque of the permanent magnet synchronous motor. This refers to the real-time rotational speed of the permanent magnet synchronous motor. The total moment of inertia of the system; The third-order extended state observer sums the frictional torque and the external disturbance torque. Estimated as an expansion state T interference = · .

3. The high-precision constant speed and force limiting coordinated control method for a motor-driven traction machine according to claim 1, characterized in that, The expression for the motor dynamics model is: ； In the formula, F For real-time traction force; This refers to the real-time output torque of the permanent magnet synchronous motor. The total moment of inertia of the system; The rate of change of speed of the permanent magnet synchronous motor; It is the sum of friction torque and external disturbance torque; i The speed ratio of the reducer; r The radius of the traction drum.

4. The high-precision constant speed and force limiting coordinated control method for a motor-driven traction machine according to claim 1, characterized in that, The formula for calculating the maximum traction force threshold is: ； In the formula, The maximum traction force threshold; This is the safety margin coefficient, with a value range of [1.1, 1.5]. This is the exponentially smoothed value of the traction force. The calculation formula is: ； In the formula, The real-time traction force for the current control cycle; α This is a smoothing coefficient, with a value range of [0.7, 0.99]. This is the exponentially smoothed value from the previous control period.

5. The high-precision constant speed and force limiting coordinated control method for a motor-driven traction machine according to claim 1, characterized in that, The formula for calculating the upper limit of safety is as follows: ； In the formula, This is the upper limit of safety. The maximum traction force threshold; r The radius of the traction drum; is the torque constant of the permanent magnet synchronous motor; i This refers to the speed ratio of the reducer.

6. The high-precision constant speed and force limiting coordinated control method for a motor-driven traction machine according to claim 1, characterized in that, The formula for calculating the real-time output torque of the permanent magnet synchronous motor based on the motor dynamics model is as follows: ； In the formula, This refers to the real-time output torque of the permanent magnet synchronous motor. is the torque constant of the permanent magnet synchronous motor; This represents the q-axis current of the permanent magnet synchronous motor.

7. The high-precision constant speed and force limiting coordinated control method for a motor-driven traction machine according to claim 1, characterized in that, The integral term accumulation of the inner loop PI regulator of the frozen current is specifically as follows: when a torque limiting command is detected, the motor controller suspends the updating of the integral term, keeping the integral term unchanged at its current value until the limiting is lifted.

8. A high-precision constant speed and force limiting coordinated control system for a motor-driven traction machine, characterized in that, The high-precision constant speed and force limiting coordinated control system for the motor-driven traction machine includes: A rotary transformer, mounted on the shaft of a permanent magnet synchronous motor, is used to collect the real-time speed of the permanent magnet synchronous motor. The current sensor, integrated into the motor controller, is used to collect the three-phase current of the permanent magnet synchronous motor. The main control unit, acting as a host computer, communicates with the motor controller via the CAN bus. It calculates the target rotational speed of the traction drum based on the target traction speed of the guide rope and the radius of the traction drum. Then, it converts the target rotational speed of the traction drum into the target rotational speed of the permanent magnet synchronous motor (PMSM) based on the speed ratio of the reducer and sends this conversion to the PMSM. It obtains the real-time rotational speed and q-axis current of the PMSM from the motor controller and calculates the real-time output torque and real-time traction force of the PMSM based on the motor dynamics model. It estimates the sum of friction torque and external disturbance torque online using a third-order extended state observer and dynamically generates a maximum traction force threshold. It determines whether the real-time traction force exceeds the maximum traction force threshold. When the real-time traction force exceeds the maximum traction force threshold, it sends a torque limiting command to the motor controller. The motor controller performs speed-current dual closed-loop control. It calculates the q-axis current through coordinate transformation, calculates the error between the real-time speed of the permanent magnet synchronous motor and the target speed of the permanent magnet synchronous motor, and inputs the speed outer loop PI regulator to generate the q-axis current command. When the real-time traction force exceeds the maximum traction force threshold, it receives a torque limiting command from the main control unit, clamps the q-axis current command to the safe upper limit, and freezes the integral term accumulation of the current inner loop PI regulator. When the real-time traction force is lower than the maximum traction force threshold, the motor controller releases the clamping limit of the q-axis current command, restores the normal accumulation of the integral term, and continues to execute the complete speed-current dual closed-loop control.

9. The high-precision constant speed and force limiting coordinated control system for a motor-driven traction machine according to claim 8, characterized in that, The main control unit includes: The traction force calculation module is used to calculate the real-time output torque and real-time traction force of the permanent magnet synchronous motor based on the motor dynamics model. The state observer module is used to estimate the sum of friction torque and external disturbance torque online through a third-order extended state observer, and dynamically generate the maximum traction force threshold. The force limiting judgment module is used to determine whether the real-time traction force exceeds the maximum traction force threshold, and sends a torque limiting command to the motor controller when the real-time traction force exceeds the maximum traction force threshold.

10. The high-precision constant speed and force limiting coordinated control system for a motor-driven traction machine according to claim 8, characterized in that, The high-precision constant speed and force limiting coordinated control system of the motor-driven traction machine also includes: a human-machine interface for setting the target value of the traction speed of the guide rope; and a communication interface for receiving traction speed commands sent by an external control system.

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