Switch machine based on servo drive and control method thereof

Abstract

The invention belongs to the technical field of rail transit, and discloses a switch machine based on servo drive and a control method thereof.The switch machine comprises a shell, a drive unit and a switching locking unit, and the drive unit and the switching locking unit are arranged in the shell; the driving unit comprises a first servo driver, a second servo driver, a permanent magnet synchronous motor and a motion conversion mechanism; the permanent magnet synchronous motor is fixed on the shell; the permanent magnet synchronous motor is in power supply and communication connection with the first servo driver and the second servo driver, the motion conversion mechanism is in transmission connection with the permanent magnet synchronous motor, and the motion conversion mechanism is further connected with the conversion locking unit; the first servo driver or the second servo driver is used for controlling the rotating speed, the torque and the start-stop position of the permanent magnet synchronous motor. According to the switch machine, the servo driver and the permanent magnet synchronous motor are adopted for providing power, parameters such as the rotating speed, the start-stop position and the torque of the permanent magnet synchronous motor are accurately controlled, and intelligent control over the switch machine is achieved.

Description

Technical Field

[0001] This invention belongs to the field of rail transit technology, and specifically relates to a servo-driven switch machine and its control method. Background Technology

[0002] As a crucial infrastructure component of railway track systems, switch machines primarily function to switch and lock turnouts, change the direction of turnout operation, and monitor the actual position of turnouts in real time. The stability and reliability of switch machine operation are critical prerequisites for ensuring railway traffic safety and improving railway transportation efficiency.

[0003] Existing switch machines generally use dedicated three-phase AC motors, with drive control achieved through forward and reverse drive circuits. This type of motor is an induction motor, widely used in the railway field. However, due to its inherent structural characteristics, this motor is difficult to control with high precision in torque, speed, and position, becoming a core bottleneck restricting the digital and intelligent upgrading of switch machine drive systems.

[0004] Furthermore, existing three-phase AC asynchronous motors lack overload self-adaptation capability. To address this issue, existing electric switch machines typically incorporate a friction coupler between the reducer and the ball screw. This coupler sets the maximum output force of the switch machine and provides overload protection for the motor. Specifically, during turnout switching, if abnormally increased turnout resistance occurs (e.g., the turnout is clamped by a foreign object), preventing the turnout from switching properly, the friction coupler can slip to prevent overload, thus preventing incorrect turnout locking or structural damage. However, traditional friction couplers employ a dry friction structure, whose friction performance is significantly affected by changes in external temperature and humidity, leading to abnormal fluctuations in friction conversion force. In extreme cases, corrosion can occur inside the friction coupler, ultimately causing a seizure fault and directly hindering normal turnout switching. Moreover, to ensure stable performance of the friction coupler, its parameters need to be adjusted periodically, significantly increasing railway maintenance workload and costs.

[0005] For multi-traction-point turnout systems, different traction points have varying requirements for the stroke parameters and rated switching force of the switch machine. Existing switch machines achieve their corresponding switching force by configuring a reducer at the motor end and using a fixed transmission ratio. To meet the stroke requirements of different traction points and the synchronization requirements between them, switch machines with different reduction ratios need to be configured for different traction points. Therefore, existing switch machines require the design of reducers with various reduction ratio specifications, which not only fails to achieve stepless speed regulation and ensures complete synchronous switching between multiple traction points, but also results in a complex array of switch machine models, increasing the difficulty of production, warehousing, and maintenance management.

[0006] In summary, existing switch machines have the following problems: they cannot achieve high-precision control of motor torque, speed and position, cannot achieve stepless speed regulation, cannot achieve complete synchronization, and have a wide variety of models, resulting in a large workload and high maintenance costs for railways. Summary of the Invention

[0007] To address the above problems, the present invention provides a servo-driven switch machine, including a housing, and a drive unit and a switching locking unit disposed within the housing; The drive unit includes a first servo driver, a second servo driver, a permanent magnet synchronous motor, and a motion conversion mechanism. The permanent magnet synchronous motor is fixed on the housing, and the first and second servo drivers are located inside the housing or beside the track. The permanent magnet synchronous motor and the first and second servo drivers are connected for power supply and communication. The motion conversion mechanism is connected to the permanent magnet synchronous motor for transmission and is also connected to the conversion locking unit. The first or second servo driver is used to control the speed, torque, and start / stop position of the permanent magnet synchronous motor.

[0008] Furthermore, the motion conversion mechanism includes a reducer, a ball screw, and transmission gears; The reducer is installed on the end face of the permanent magnet synchronous motor or built into the permanent magnet synchronous motor; the transmission gear is fixedly installed at one end of the ball screw, and the ball screw is connected to the reducer through the transmission gear. The ball screw is connected to the actuating rod of the conversion locking unit.

[0009] Furthermore, it also includes a display unit disposed within the housing, which is used to display the state of the switching locking unit.

[0010] Furthermore, both the first servo driver and the second servo driver include a speed regulation module and a current regulation module; The speed control module is used to dynamically adjust the output current to precisely control the speed of the permanent magnet synchronous motor; the current regulation module is used to regulate the output current and control the torque of the permanent magnet synchronous motor using the torque-current relationship.

[0011] The present invention also provides a control method for a servo-driven switch machine, used in the aforementioned servo-driven switch machine, comprising the following steps: After receiving the turnout switching command, the first servo driver or the second servo driver drives the permanent magnet synchronous motor to rotate. The motion conversion mechanism converts the rotational motion of the permanent magnet synchronous motor into linear motion, which in turn drives the switching and locking unit to complete the turnout switching and locking actions. The first servo driver or the second servo driver collects the position information of the permanent magnet synchronous motor in real time. When the position collected by the first servo driver or the second servo driver is consistent with the limit position, it is determined that the conversion is in place, and the first servo driver or the second servo driver drives the permanent magnet synchronous motor to stop rotating. During turnout switching, the first or second servo driver controls the speed, torque, and start / stop position of the permanent magnet synchronous motor.

[0012] Furthermore, the first servo driver or the second servo driver controls the speed of the permanent magnet synchronous motor, including the following steps: The first or second servo driver controls the soft start and soft stop of the permanent magnet synchronous motor. Depending on the different positions the switch machine has switched to, the output current is dynamically adjusted to control the permanent magnet synchronous motor to execute different speeds.

[0013] Furthermore, the first servo driver or the second servo driver controls the torque of the permanent magnet synchronous motor, including the following steps: The current of the permanent magnet synchronous motor is acquired by the first servo driver or the second servo driver, and the torque of the permanent magnet synchronous motor is controlled by adjusting the output current using the torque-current relationship. The first servo driver or the second servo driver has a maximum torque limit. The rated torque of the permanent magnet synchronous motor is set by the first servo driver or the second servo driver to control the maximum output force of the switch machine.

[0014] Furthermore, controlling the start and stop positions of the permanent magnet synchronous motor via a first servo driver or a second servo driver includes the following steps: When the switch machine is switched to the limit position, the first servo driver or the second servo driver records the limit position as a start / stop position reference, sets the limit position of the permanent magnet synchronous motor, and when the first servo driver or the second servo driver executes the operation command, it controls the start / stop of the permanent magnet synchronous motor at the limit position.

[0015] Furthermore, it also includes the following steps: The first servo driver and the second servo driver provide redundant drive for the permanent magnet synchronous motor. One servo driver is the primary drive, while the other servo driver is either hot or cold standby.

[0016] Furthermore, it also includes the following steps: The first and second servo drives collect their own status data. If a fault occurs, the fault information is uploaded and the system switches to the backup servo drive.

[0017] The beneficial effects of this invention are: 1. The switch machine of the present invention uses a servo driver and a permanent magnet synchronous motor to provide power. The speed, start and stop position, torque and other parameters of the permanent magnet synchronous motor can be precisely controlled by the servo driver to realize intelligent control of the switch machine.

[0018] 2. The permanent magnet synchronous motor and servo driver used in the switch machine of the present invention can control the maximum output force of the switch machine, and have their own overload protection function, eliminating the need for the friction coupling of the existing switch machine.

[0019] 3. The switch machine of the present invention sets the rated speed and torque of the motor through a servo driver. Different rated speeds and torques can be set for a single type of switch machine to meet the switching force requirements of switch machines at different traction points of the turnout. Furthermore, by utilizing the stepless speed regulation of the permanent magnet synchronous motor, the synchronicity of turnout switching can be better guaranteed.

[0020] 4. The switch machine of the present invention utilizes the start and stop position control of a permanent magnet synchronous motor and a servo driver to precisely control the switching position of the switch machine, monitor the position information of the switch machine in real time, and make reasonable configurations for different requirements of the switching stroke at different traction points.

[0021] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A schematic diagram of a servo-driven switch machine according to an embodiment of the present invention is shown; Figure 2 A schematic diagram of the structure of the drive unit according to an embodiment of the present invention is shown; Figure 3 A schematic flowchart of a control method for a servo-driven switch machine according to an embodiment of the present invention is shown.

[0024] In the diagram: 1. Housing; 2. Drive unit; 21. First servo driver; 22. Second servo driver; 23. Permanent magnet synchronous motor; 24. Reducer; 25. Ball screw; 26. Transmission gear; 3. Conversion locking unit; 4. Display unit. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] It should be noted that the terms "first," "second," etc., used in this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," "longitudinal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings.

[0027] This invention provides a servo-driven switch machine and its control method, which can precisely control parameters such as motor speed, position, and torque, and control the maximum output force of the switch machine, eliminating the need for existing friction couplings. By setting different rated torques and speeds, the rated switching force and speed of the switch machine can be adjusted to meet the switching force requirements of switch machines at different traction points of the turnout. This invention also enables stepless speed regulation of the motor, which can better ensure the synchronization of turnout switching. This invention can precisely control the switching position of the switch machine, monitor the position information of the switch machine in real time, realize digital intelligent control of the switch machine, and improve the reliability of the switch machine.

[0028] like Figure 1 As shown, a servo-driven switch machine includes a housing 1, and a drive unit 2, a switching locking unit 3, and an indication unit 4 disposed within the housing 1.

[0029] like Figure 2 As shown, the drive unit 2 includes a first servo driver 21, a second servo driver 22, a permanent magnet synchronous motor 23, and a motion conversion mechanism. The permanent magnet synchronous motor 23 is fixed on the housing 1. The first servo driver 21 and the second servo driver 22 can be installed inside the housing 1 or installed beside the track.

[0030] The permanent magnet synchronous motor 23 is electrically connected to the first servo driver 21 and the second servo driver 22 via power lines and communication lines. The first servo driver 21 and the second servo driver 22 provide drive power to the permanent magnet synchronous motor 23 and communicate position information with the permanent magnet synchronous motor 23. The motion conversion mechanism is connected to the permanent magnet synchronous motor 23 for transmission and is also connected to the conversion locking unit 3. The display unit 4 is disposed in the housing 1 and is used to display the state of the conversion locking unit 3.

[0031] When the turnout is switched, the first servo driver 21 or the second servo driver 22 drives the permanent magnet synchronous motor 23 to rotate, which drives the motion conversion mechanism to move. The motion conversion mechanism converts the rotational motion into linear motion, which pushes the switching and locking unit 3 to complete the turnout switching and locking action. After the switch is in place, it drives the display unit 4 to give an indication signal.

[0032] For example, the motion conversion mechanism includes a reducer 24, a ball screw 25, and a transmission gear 26. The reducer 24 is mounted on the end face of the permanent magnet synchronous motor 23 or built into the permanent magnet synchronous motor 23. The transmission gear 26 is fixedly set at one end of the ball screw 25. The ball screw 25 is connected to the reducer 24 through the transmission gear 26. The ball screw 25 is connected to the actuating rod of the conversion locking unit 3.

[0033] In this embodiment of the invention, a reducer 24 of a certain specification is added between the output end of the permanent magnet synchronous motor 23 and the ball screw 25 to improve the switching force of the switch machine.

[0034] To ensure the reliability of the servo drivers, this invention employs a first servo driver 21 and a second servo driver 22 to redundantly drive the permanent magnet synchronous motor 23. When the switch machine is operating normally, the first servo driver 21 controls the permanent magnet synchronous motor 23, while the second servo driver 22 is either in hot or cold standby mode. Furthermore, both the first and second servo drivers 21 and 22 have self-testing functions, collecting their own status data. If a fault occurs, the information is uploaded, and the system switches to the other servo driver.

[0035] The switch machine of the present invention is powered by a first servo driver 21, a second servo driver 22 and a permanent magnet synchronous motor 23. The speed, position and torque of the permanent magnet synchronous motor 23 can be precisely controlled by the first servo driver 21 or the second servo driver 22. The same switch machine can be reasonably configured according to different operating conditions.

[0036] For example, based on the operating conditions of the switch machine, the rated torque and other parameters of the permanent magnet synchronous motor 23 are set by the first servo driver 21 and the second servo driver 22 to control the maximum output force of the switch machine to meet the turnout installation requirements. At the same time, when the turnout resistance exceeds the maximum output force of the switch machine, the permanent magnet synchronous motor 23 can adapt to the overload by itself, and the existing friction coupling is no longer needed, thus avoiding the maintenance workload caused by friction coupling problems.

[0037] For example, the rated speed and torque of the permanent magnet synchronous motor 23 can be set by the first servo driver 21 and the second servo driver 22. By setting different rated torques and speeds for the permanent magnet synchronous motor 23, the same switch machine can adapt to the different rated switching force requirements of switch machines with different strokes. Furthermore, the stepless speed regulation of the permanent magnet synchronous motor 23 can better ensure the synchronization of turnout switching at different traction points. For example, three uniformly configured switch machines can have different rated torques and speeds of the permanent magnet synchronous motor 23 set by the first servo driver 21 and the second servo driver 22 according to the torque and speed requirements of different traction points, and can be installed on three-point traction turnouts.

[0038] For example, both the first servo driver 21 and the second servo driver 22 are equipped with a speed adjustment module. The first servo driver 21 or the second servo driver 22 dynamically adjusts the output current through the speed control module based on the feedback parameters from the permanent magnet synchronous motor 23, thereby precisely controlling the speed of the permanent magnet synchronous motor 23. The switch machine uses the servo driver to control the speed of the permanent magnet synchronous motor 23. The switch machine can be set to different speeds through the speed control of the servo driver to adapt to the speed requirements of different traction point switches, thus better ensuring the synchronicity of switch switching.

[0039] For example, both the first servo driver 21 and the second servo driver 22 are equipped with a current regulation module. The first servo driver 21 or the second servo driver 22 collects the three-phase current of the permanent magnet synchronous motor 23 and adjusts the output current through the current regulation module. The torque of the permanent magnet synchronous motor 23 is controlled by the torque-current relationship.

[0040] For example, the switch machine utilizes the position control of the permanent magnet synchronous motor 23 and the first servo driver 21 and the second servo driver 22 to precisely control the switching position of the switch machine and monitor its operation in real time. For instance, based on the requirements of different traction points for the switch machine's travel, the position of the permanent magnet synchronous motor 23 is precisely controlled by the first servo driver 21 and the second servo driver 22, thereby ensuring the accuracy of the switch machine's displacement and improving its safety and reliability.

[0041] During turnout switching, the first servo driver 21 and the second servo driver 22 receive instructions from the upper control system and drive the permanent magnet synchronous motor 23 to rotate forward / reverse. The permanent magnet synchronous motor 23 drives the reducer 24 to rotate synchronously, and drives the ball screw 25 to rotate through the transmission gear 26. The ball screw 25 converts the rotational motion into linear motion, which pushes the switching and locking unit 3 to complete the turnout switching and locking action. The first servo driver 21 and the second servo driver 22 collect the position information of the permanent magnet synchronous motor 23 in real time. When the position collected by the first servo driver 21 and the second servo driver 22 is consistent with the limit position, it is considered that the switch is in place, and the indication unit 4 gives an indication signal. The first servo driver 21 and the second servo driver 22 drive the permanent magnet synchronous motor 23 to stop rotating.

[0042] After the first servo drive 21 and the second servo drive 22 are first powered on or after a power outage and restart, they need to learn their limit positions. The upper control system sends a command to drive the first servo drive 21 or the second servo drive 22 and the permanent magnet synchronous motor 23 to execute a switching command, causing the switch machine to switch to the stall position. The first servo drive 21 or the second servo drive 22 records the current position as a reference for setting its limit position. The upper control system controls the first servo drive 21 or the second servo drive 22 and the permanent magnet synchronous motor 23 to execute forward and reverse commands once each, thus obtaining the limit positions of the switch machine when pulled in and extended.

[0043] To ensure the reliability of the servo drives, the permanent magnet synchronous motor 23 is redundantly driven by the first servo drive 21 and the second servo drive 22. The first servo drive 21 and the second servo drive 22 have self-testing functions. The first servo drive 21 and the second servo drive 22 collect their own status, and once fault information (voltage, current, temperature, etc. exceed the set value) occurs, the information is uploaded and a switch is initiated.

[0044] like Figure 3 As shown in the figure, this embodiment of the invention also provides a control method for a switch machine based on servo drive, including the following steps: S1. After receiving the turnout switching command from the upper control system, the first servo driver 21 or the second servo driver 22 drives the permanent magnet synchronous motor 23 to rotate forward / reverse. The motion conversion mechanism converts the rotational motion of the permanent magnet synchronous motor 23 into linear motion, pushing the switching and locking unit 3 to complete the turnout switching and locking action. The first servo driver 21 or the second servo driver 22 collects the position information of the permanent magnet synchronous motor 23 in real time. When the position collected by the first servo driver 21 or the second servo driver 22 is consistent with the limit position, it is determined that the switch is in place, and the indication unit 4 gives an indication signal. The first servo driver 21 or the second servo driver 22 drives the permanent magnet synchronous motor 23 to stop rotating.

[0045] S2. During the turnout switching process, the first servo driver 21 or the second servo driver 22 controls the speed, torque and start / stop position of the permanent magnet synchronous motor 23.

[0046] The first servo driver 21 or the second servo driver 22 controls the speed of the permanent magnet synchronous motor 23, including the following steps: the first servo driver 21 or the second servo driver 22 controls the soft start and soft stop of the permanent magnet synchronous motor 23, and controls the permanent magnet synchronous motor 23 to execute different speeds by dynamically adjusting the output current according to the different positions of the switch machine, so as to reduce the inertial impact of the rotation of the permanent magnet synchronous motor 23 and prevent the switch machine from rebounding and unlocking.

[0047] The first servo driver 21 or the second servo driver 22 controls the torque of the permanent magnet synchronous motor 23 by means of the following steps: acquiring the three-phase current of the permanent magnet synchronous motor 23 through the first servo driver 21 or the second servo driver 22, and controlling the torque of the permanent magnet synchronous motor 23 by adjusting the output current and using the torque-current relationship. The first servo driver 21 or the second servo driver 22 has a maximum torque limit. The rated torque of the permanent magnet synchronous motor 23 is set by the first servo driver 21 or the second servo driver 22 to control the maximum output force of the switch machine. It can also adapt to overload through the servo driver and the permanent magnet synchronous motor 23.

[0048] In this embodiment of the invention, the start and stop positions of the permanent magnet synchronous motor 23 are controlled by the first servo driver 21 or the second servo driver 22. The position control of the permanent magnet synchronous motor 23 and the servo driver can be used to achieve precise control of the switching position of the switch machine.

[0049] The servo driver in this embodiment of the invention adopts closed-loop control to precisely control the current, speed and position of the permanent magnet synchronous motor 23, thereby realizing digital intelligent control of the switch machine drive.

[0050] For example, the start and stop positions of the permanent magnet synchronous motor 23 can be controlled by the first servo driver 21 or the second servo driver 22 through self-learning of the servo driver, including the following steps: When the upper control system controls the switch machine to switch to the limit position (locked position), the first servo driver 21 or the second servo driver 22 records the limit position as a start / stop position reference and sets the limit position of the permanent magnet synchronous motor 23. When the first servo driver 21 or the second servo driver 22 executes the operation command, it controls the start / stop of the permanent magnet synchronous motor 23 at the limit position to achieve precise control of the switch machine's switching position, monitor the switch machine's position information in real time, and make reasonable configurations for different requirements of the switch stroke at different traction points.

[0051] After the first servo drive 21 and the second servo drive 22 are first powered on or after a power outage and restart, they need to learn their limit positions. The upper control system sends a command to the first servo drive 21 or the second servo drive 22, which drives the permanent magnet synchronous motor 23 to execute the switching command, switching the switch machine to the stall position. The first servo drive 21 or the second servo drive 22 records the limit position as a reference for the start and stop positions, and sets the limit position of the permanent magnet synchronous motor 23. The upper control system controls the servo drive and the permanent magnet synchronous motor 23 to execute forward and reverse commands once each, thus obtaining the limit positions of the switch machine when pulled in and extended.

[0052] S3. To ensure the reliability of the servo drive, a first servo drive 21 and a second servo drive 22 are used to redundantly drive the permanent magnet synchronous motor 23. One servo drive is the primary drive, and the other servo drive is either hot standby or cold standby.

[0053] S4. The first servo driver 21 and the second servo driver 22 have self-test functions. The first servo driver 21 and the second servo driver 22 collect their own status. Once a fault occurs (voltage, current, temperature, etc. exceed the set value), the fault information is uploaded and a backup servo driver is switched.

[0054] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A servo-driven switch machine, characterized in that, It includes a housing (1), and a drive unit (2) and a conversion locking unit (3) disposed within the housing (1); The drive unit (2) includes a first servo driver (21), a second servo driver (22), a permanent magnet synchronous motor (23), and a motion conversion mechanism. The permanent magnet synchronous motor (23) is fixed on the housing (1). The first servo driver (21) and the second servo driver (22) are disposed inside the housing (1) or beside the track. The permanent magnet synchronous motor (23) is connected to the first servo driver (21) and the second servo driver (22) for power supply and communication. The motion conversion mechanism is connected to the permanent magnet synchronous motor (23) for transmission. The motion conversion mechanism is also connected to the conversion locking unit (3). The first servo driver (21) or the second servo driver (22) is used to control the speed, torque and start / stop position of the permanent magnet synchronous motor (23).

2. The servo-driven switch machine according to claim 1, characterized in that, The motion conversion mechanism includes a reducer (24), a ball screw (25), and a transmission gear (26); The reducer (24) is installed on the end face of the permanent magnet synchronous motor (23) or built into the permanent magnet synchronous motor (23); the transmission gear (26) is fixedly installed at one end of the ball screw (25), the ball screw (25) is connected to the reducer (24) through the transmission gear (26), and the ball screw (25) is connected to the actuating rod of the conversion locking unit (3).

3. The servo-driven switch machine according to claim 1 or 2, characterized in that, It also includes a display unit (4), which is disposed inside the housing (1) and is used to display the state of the switching locking unit (3).

4. The servo-driven switch machine according to claim 1, characterized in that, Both the first servo driver (21) and the second servo driver (22) include a speed regulation module and a current regulation module; The speed control module is used to dynamically adjust the output current and precisely control the speed of the permanent magnet synchronous motor (23); the current regulation module is used to regulate the output current and control the torque of the permanent magnet synchronous motor (23) using the torque-current relationship.

5. A control method for a switch machine based on servo drive, characterized in that, The servo-driven switch machine according to any one of claims 1-4 comprises the following steps: After receiving the turnout conversion command, the first servo driver (21) or the second servo driver (22) drives the permanent magnet synchronous motor (23) to rotate. The motion conversion mechanism converts the rotational motion of the permanent magnet synchronous motor (23) into linear motion, and pushes the conversion locking unit (3) to complete the turnout conversion and locking action. The first servo driver (21) or the second servo driver (22) collects the position information of the permanent magnet synchronous motor (23) in real time. When the position collected by the first servo driver (21) or the second servo driver (22) is consistent with the limit position, it is determined that the conversion is in place, and the first servo driver (21) or the second servo driver (22) drives the permanent magnet synchronous motor (23) to stop rotating. During the turnout switching process, the first servo driver (21) or the second servo driver (22) controls the speed, torque and start / stop position of the permanent magnet synchronous motor (23).

6. The control method for a switch machine based on servo drive according to claim 5, characterized in that, The first servo driver (21) or the second servo driver (22) controls the speed of the permanent magnet synchronous motor (23), including the following steps: The first servo driver (21) or the second servo driver (22) controls the soft start and soft stop of the permanent magnet synchronous motor (23). Depending on the different positions the switch machine is switched to, the output current is dynamically adjusted to control the permanent magnet synchronous motor (23) to execute different speeds.

7. The control method for a switch machine based on servo drive according to claim 5, characterized in that, The first servo driver (21) or the second servo driver (22) controls the torque of the permanent magnet synchronous motor (23) by means of the following steps: The current of the permanent magnet synchronous motor (23) is collected by the first servo driver (21) or the second servo driver (22), and the torque of the permanent magnet synchronous motor (23) is controlled by adjusting the output current and utilizing the torque-current relationship. The first servo driver (21) or the second servo driver (22) has a maximum torque limit. The rated torque of the permanent magnet synchronous motor (23) is set by the first servo driver (21) or the second servo driver (22), thereby controlling the maximum output force of the switch machine.

8. The control method for a switch machine based on servo drive according to claim 5, characterized in that, The start and stop positions of the permanent magnet synchronous motor (23) are controlled by the first servo driver (21) or the second servo driver (22), including the following steps: When the switch machine is switched to the limit position, the first servo driver (21) or the second servo driver (22) records the limit position as a start / stop position reference and sets the limit position of the permanent magnet synchronous motor (23). When the first servo driver (21) or the second servo driver (22) executes the operation command, the permanent magnet synchronous motor (23) is started and stopped at the limit position.

9. The control method for a switch machine based on servo drive according to any one of claims 5-8, characterized in that, It also includes the following steps: The first servo driver (21) and the second servo driver (22) provide redundant drive for the permanent magnet synchronous motor (23), with one servo driver being the primary drive and the other servo driver being either hot or cold standby.

10. The control method for a switch machine based on servo drive according to claim 9, characterized in that, It also includes the following steps: The first servo driver (21) and the second servo driver (22) collect their own status. After a fault occurs, they upload the fault information and switch to the backup servo driver.

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