Rail transit drive safety isolation device, system and method

Abstract

This invention relates to the field of traction electric drive systems for rail transit trains, and more specifically, to a rail transit transmission safety isolation device, system, and method. The rail transit transmission safety isolation device provided by this invention is installed on the torque transmission path between the traction motor and the wheelset, and includes a spline, a sliding sleeve, a drive motor, a lead screw mechanism, and a position detection switch: the spline is used to connect to the output shaft of the traction motor, and the sliding sleeve is used to connect to the input shaft of the wheelset. The establishment or decoupling of the mechanical transmission connection between the traction motor and the wheelset is achieved by the axial movement of the sliding sleeve along the spline; the position detection switch is used to detect the connection or decoupling status of the spline and the sliding sleeve. This invention, by integrating a mechanical transmission safety isolation device on the torque transmission path between the traction motor and the wheelset, achieves rapid switching of the mechanical transmission chain under fault conditions, thus replacing electrical isolation with physical isolation and improving the safety and reliability of the traction system.

Description

Technical Field

[0001] This invention relates to the field of rail transit train traction electric drive system technology, and more specifically, to a rail transit transmission safety isolation device, a traction electric drive system, and a rail transit transmission safety isolation control method. Background Technology

[0002] With the rapid development of rail transit equipment, increasingly higher requirements are being placed on the equipment's safety, reliability, and efficiency. Permanent magnet synchronous motors (PMSMs), due to their high efficiency and high power density, have become an important development direction for rail transit traction electric drive systems. However, the inherent no-load back EMF characteristic of PMSMs poses certain safety risks to the system. When an inter-turn or phase-to-phase short circuit occurs inside the PMSM, abnormally high voltage is generated, which may cause reverse breakdown of front-end power devices such as the IGBT modules and capacitors in the converter, and even lead to serious accidents such as arcing and fire.

[0003] Therefore, permanent magnet traction systems need to consider electrical isolation under motor failure conditions. Currently, the mainstream solution achieves this through electrical isolation, employing a dual diagnostic protection approach combining software and hardware. The core of this approach lies in installing isolation contactors in the three-phase output circuit.

[0004] However, existing technologies have the following shortcomings: under extreme fault conditions, isolating contactors cannot achieve complete fault isolation; more importantly, the isolating contactor itself may also fail, in which case it not only fails to provide isolation protection but may also cause the fault to escalate, endangering train operation safety. Therefore, simply relying on electrical isolation methods cannot fundamentally solve the problem of safe isolation after a permanent magnet motor failure.

[0005] Therefore, a technical solution is needed to achieve mechanical isolation between the permanent magnet motor and the transmission system through physical means to make up for the lack of electrical isolation, and to ensure that the torque transmission path between the faulty motor and the wheelset can be reliably and completely disconnected under extreme fault conditions, thereby ensuring the safety of train operation. Summary of the Invention

[0006] The purpose of this invention is to provide a safety isolation device for rail transit transmission, a matching traction electric transmission system, and a corresponding control method to solve the problem that existing permanent magnet traction systems are difficult to reliably isolate faults under extreme fault conditions and pose safety risks.

[0007] To achieve the above objectives, the present invention provides a safety isolation device for rail transit transmission, installed on the torque transmission path between the traction motor and the wheelset, comprising a spline, a sliding sleeve, a drive motor, a lead screw mechanism, and a position detection switch. The spline is used to connect with the output shaft of the traction motor, and the sliding sleeve is used to connect with the input shaft of the wheelset. The spline and the sliding sleeve are slidably engaged. The mechanical transmission connection between the traction motor and the wheelset is established or decoupled by the movement of the sliding sleeve along the axial direction of the spline. The drive motor is connected to the lead screw mechanism, and the lead screw mechanism is connected to the sliding sleeve, for driving the sliding sleeve to move; The position detection switch is used to detect the connection or decoupling status of the spline and the sliding sleeve.

[0008] In some embodiments, the torque transmission path includes the traction motor and the coupling, the coupling and the gearbox, the wheel axle and the gearbox, or the traction motor and the wheel axle.

[0009] In some embodiments, the drive motor is powered by AC380V, AC220V, AC110V or DC24V power supply.

[0010] In some embodiments, the spline and the sliding sleeve are mechanically limited by a groove connection to prevent miscoupling of the mechanical transmission connection during vehicle operation.

[0011] In some embodiments, the position detection switch is a contact pressure switch or a non-contact photoelectric switch, disposed on opposite sides of the spline, and is used to provide a switching signal to the traction control unit to characterize the connection state, decoupling state, neutral state, or invalid state.

[0012] In some embodiments, the rail transit transmission safety isolation device further includes a reset mechanism configured to reset manually or automatically after a fault is cleared, so as to restore the mechanical transmission connection between the traction motor and the wheelset.

[0013] To achieve the above objectives, the present invention also proposes a traction electric drive system, including a traction control unit, a traction motor, a transmission mechanism, and the aforementioned rail transit transmission safety isolation device. The traction control unit is connected to the traction motor and is used to control the operation of the traction motor, monitor system faults, and control the operation of the rail transit transmission safety isolation device. The traction motor is connected to the rail transit transmission safety isolation device and is used to output power; The transmission mechanism is connected to the rail transit transmission safety isolation device and is used to transmit power to the wheelset; The rail transit transmission safety isolation device is connected between the traction motor and the transmission mechanism; The traction control unit is configured to implement a fault classification protection strategy: based on the severity level of the traction system fault, it controls the rail transit transmission safety isolation device to perform corresponding actions.

[0014] In some embodiments, the fault classification protection strategy includes: When the fault severity level is minor, the rail transit transmission safety isolation device is kept connected and only reports the fault. When the fault severity level is medium, the rail transit transmission safety isolation device is reset and the fault status is re-detected. When the fault severity level is a severe fault, the rail transit transmission safety isolation device is controlled to perform a mechanical decoupling action.

[0015] In some embodiments, the traction motor is a permanent magnet motor; The traction control unit is also configured to: For a two-phase short-circuit fault in a permanent magnet motor, the control first switches to a three-phase short circuit before executing the mechanical decoupling action of the rail transit transmission safety isolation device. For three-phase short circuit or inter-turn short circuit faults in permanent magnet motors, the mechanical decoupling action of the rail transit transmission safety isolation device is executed after the train stops and the fault is reconfirmed.

[0016] In some embodiments, the traction control unit is further configured to execute exception handling logic: If no connection status feedback is received within a preset time after issuing the reconnection command, the drive motor is powered off and reversed to the neutral position. Then, the reconnection command is issued again, and the traction motor is driven to rotate at a predetermined speed.

[0017] In some embodiments, the traction control unit is further configured with power-on self-test logic: Each time the train is powered on, the control system of the rail transit transmission safety isolation device sequentially performs connection status detection, decoupling action and connection restoration action to complete the full process verification; If any step is abnormal, the system will try again a preset number of times. If the problem persists, a self-test fault alarm will be output.

[0018] To achieve the above objectives, this invention proposes a safety isolation control method for rail transit transmission, applied to the aforementioned traction electric transmission system, comprising the following steps: After the train is powered on, the traction control unit controls the rail transit transmission safety isolation device to perform a power-on self-test, completing the full-process verification of connection status detection, decoupling action and reconnection action; The traction control unit monitors the fault status of the traction system and the position status of the rail transit transmission safety isolation device in real time. Based on the severity level of the traction system fault, a fault classification protection strategy is implemented to control the rail transit transmission safety isolation device to perform corresponding actions; After the fault is cleared, the traction control unit resets the rail transit transmission safety isolation device, restoring the mechanical transmission connection between the traction motor and the wheelset.

[0019] This invention provides a rail transit transmission safety isolation device, a matching traction electric transmission system, and a corresponding control method. By integrating a mechanical transmission safety isolation device into the torque transmission path between the traction motor and the wheelset, it enables rapid switching of the mechanical transmission chain under fault conditions, thereby achieving the goal of replacing electrical isolation with physical isolation and improving the safety and reliability of the traction system. Attached Figure Description

[0020] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always denote the same features, wherein: Figure 1 A schematic diagram illustrating the system composition principle of a rail transit transmission safety isolation device according to an embodiment of the present invention is disclosed; Figure 2 A schematic diagram showing the first and second installation positions of a rail transit transmission safety isolation device according to an embodiment of the present invention is provided. Figure 3 A schematic diagram showing the third installation position of a rail transit transmission safety isolation device according to an embodiment of the present invention is provided. Figure 4 A schematic diagram showing the fourth installation position of a rail transit transmission safety isolation device according to an embodiment of the present invention is provided. Figure 5 A schematic diagram of a typical main circuit of a traditional traction electric drive system is shown. Figure 6 A typical main circuit diagram of a traction electric drive system according to an embodiment of the present invention is disclosed. Figure 7 A fault diagnosis and protection logic diagram of a traction electric drive system according to an embodiment of the present invention is disclosed; Figure 8 A logic diagram of the decoupling process of a rail transit transmission safety isolation device according to an embodiment of the present invention is disclosed; Figure 9 A logic diagram of the reconnection process of a rail transit transmission safety isolation device according to an embodiment of the present invention is disclosed; Figure 10 A logic diagram for handling abnormal situations during the decoupling process of a rail transit transmission safety isolation device according to an embodiment of the present invention is disclosed. Figure 11 A logic diagram for handling abnormal situations during the reconnection process of a rail transit transmission safety isolation device according to an embodiment of the present invention is disclosed.

[0021] The meanings of the labels in the figures are as follows: 100 Rail Transit Transmission Safety Isolation Device; 11 First installation position; 12 Second installation position; 13 Third installation position; 14 Fourth installation position; 101 splines; 102 Sliding Sleeve; 103 drive motor; 104 lead screw mechanism; 105 position detection switch; 106 casing; 110 power input shaft; 120 power take-off shaft; 210 permanent magnet motor; 211 motor output shaft; 220 gearbox; 221 gearbox input shaft; 222 gearbox output shaft; 230 wheels; 231 wheel axle; 240 coupling; 50 traction converter; 51 pre-charge circuit; 52 Current Sensor; 53 Reactors; 541 First capacitor; 542 Second Capacitor; 55 chopper circuit; 561 First Inverter Module; 562 Second Inverter Module; 57 Three-phase isolated output contactor. Detailed Implementation

[0022] 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 and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0023] This invention relates to the field of traction electric drive system technology for rail transit trains, specifically to a safety-guided transmission safety isolation device, a traction electric drive system equipped with the device, and a corresponding control method.

[0024] To address the problem that traditional solutions struggle to reliably isolate serious faults such as inter-turn short circuits and phase-to-phase short circuits in permanent magnet motors, this invention proposes a safety-guided transmission safety isolation device. This device is installed on the torque transmission path between the traction motor and the wheelset. Under fault conditions, it can disconnect the mechanical transmission connection between the traction motor and the wheel axle. In the event of serious electrical faults in the traction motor or traction converter, or major faults in the transmission system, it achieves physical isolation of the transmission chain. After the fault is cleared, it can be automatically or manually reset, ensuring efficient and safe train operation.

[0025] Figure 1 A schematic diagram of a rail transit transmission safety isolation device according to an embodiment of the present invention is disclosed, such as... Figure 1 As shown, the rail transit transmission safety isolation device 100 proposed in this invention is installed on the torque transmission path between the traction motor and the wheelset. It includes a spline 101, a sliding sleeve 102, a drive motor 103, a lead screw mechanism 104, and a position detection switch 105. The components work together to achieve the connection and decoupling of the power transmission. The specific structure and function are as follows: The spline 101 and the sliding sleeve 102 cooperate with each other through a slidable meshing structure to establish or decouple the mechanical transmission connection between the traction motor and the wheelset. The spline 101 is fixedly connected to the output shaft (i.e., power input shaft 110) of the traction motor, and the sliding sleeve 102 is fixedly connected to the input shaft (i.e., power output shaft 120) of the wheelset. The sliding sleeve 102 can slide along the axial direction of the spline 101 to achieve engagement or disengagement, thereby switching the transmission link between the traction motor and the wheelset on or off.

[0026] The drive motor 103 is connected to the lead screw mechanism 104. The power output by the drive motor 103 is converted into linear motion through the lead screw mechanism 104, which is used to drive the sliding sleeve 102 to move axially along the spline 101, thereby controlling the meshing state of the spline 101 and the sliding sleeve 102, and realizing the establishment or decoupling of the transmission connection. The position detection switch 105 is used to detect the connection or decoupling status of the spline 101 and the sliding sleeve 102 in real time, and feeds back the detected status signal to the traction control unit (TCU) to provide a basis for issuing commands to the traction control unit.

[0027] The rail transit transmission safety isolation device 100 is a lead screw actuator driven by the drive motor 103. The components are highly integrated and can form a miniaturized drive system. It can fit into the compact installation space of the rail transit bogie without making major modifications to the original structure of the bogie, and is highly practical.

[0028] In this embodiment, the traction motor can be a permanent magnet motor 210, and the wheelset can be a wheel 230.

[0029] The torque transmission path is the power transmission path between the permanent magnet motor 210 and the wheel 230 (wheelset), which may specifically include: between the permanent magnet motor 210 and the coupling 240, between the coupling 240 and the gearbox 220, between the permanent magnet motor 210 and the gearbox 220, or between the permanent magnet motor 210 and the wheel 230.

[0030] The rail transit transmission safety isolation device 100 can be integrated into any of the above-mentioned torque transmission positions according to actual installation requirements. The device is usually integrated into the train bogie. During the installation process, the original transmission architecture of the train is not changed. It can be directly adapted to the traction transmission system of existing rail transit trains, reducing the cost of modification.

[0031] Figure 2 A schematic diagram illustrating the first and second installation positions of a rail transit transmission safety isolation device according to an embodiment of the present invention is shown, as follows: Figure 2 As shown, the first installation position 11 is set between the motor output shaft 211 of the permanent magnet motor 210 and the coupling 240. At this time, the rail transit transmission safety isolation device 100 is connected in series on the transmission chain between the permanent magnet motor 210 and the coupling 240 to control the power on / off control between the two. The second installation position 12 is set between the coupling 240 and the gearbox input shaft 221 of the gearbox 220. The rail transit transmission safety isolation device 100 is connected in series on the transmission chain between the coupling 240 and the gearbox 220 to realize the power on / off control between the two.

[0032] Figure 3 A schematic diagram illustrating the third installation position of a rail transit transmission safety isolation device according to an embodiment of the present invention is shown, as follows. Figure 3 As shown, the third installation position 13 is set between the gearbox output shaft 222 of the gearbox 220 and the wheel axle 231 of the wheel 230. The rail transit transmission safety isolation device 100 is connected in series on the transmission chain between the gearbox 220 and the wheel 230, directly controlling the transmission and decoupling of the power output from the gearbox 220 to the wheel 230.

[0033] Figure 4 A schematic diagram illustrating the fourth installation position of a rail transit transmission safety isolation device according to an embodiment of the present invention is shown, as follows. Figure 4 As shown, the fourth installation position 14 is set between the motor output shaft 211 of the permanent magnet motor 210 and the wheel axle 231 of the wheel 230. The rail transit transmission safety isolation device 100 is directly connected in series between the permanent magnet motor 210 and the wheel 230, bypassing the intermediate transmission components, and realizing direct control of the power transmission between the permanent magnet motor 210 and the wheel 230, adapting to different traction system layout requirements.

[0034] In some embodiments, the drive motor is powered by AC380V, AC220V, AC110V or DC24V power supply, which can flexibly adapt to different power supply circuits on the train, without the need for additional dedicated power supply equipment, thus improving the versatility of the device.

[0035] In some embodiments, the lead screw mechanism 104 is a planetary roller lead screw, which has a self-locking characteristic. When the drive motor 103 stops rotating, the planetary roller lead screw can achieve self-locking, thereby fixing the position of the sliding sleeve 102 and preventing the sliding sleeve 102 from being displaced due to external forces such as vibration and impact during train operation.

[0036] Preferably, during normal vehicle operation, the rail transit transmission safety isolation device 100, through the self-locking characteristics of the planetary roller screw, combined with the mechanical limiting structure of the spline 101 and the sliding sleeve 102, forms a double anti-maloperation protection, which can effectively avoid miscoupling of the mechanical transmission connection during operation, ensure the stability and safety of the train traction transmission, and eliminate the driving safety hazards caused by miscoupling.

[0037] In some embodiments, the spline 101 and the sliding sleeve 102 form a mechanical limiting structure through a groove fit. Specifically, a limiting groove can be provided on the spline 101, and a limiting protrusion adapted to the limiting groove can be provided on the sliding sleeve 102. When the spline 101 and the sliding sleeve 102 are fully engaged (connected state) or fully separated (decoupled state), the limiting protrusion is engaged in the limiting groove to achieve mechanical limiting. This is used to prevent relative displacement between the spline 101 and the sliding sleeve 102 due to vibration and impact during vehicle operation, thereby avoiding miscoupling of the mechanical transmission connection. The structural limiting further improves the stability and safety of the transmission connection.

[0038] In some embodiments, the position detection switch 105 is a contact pressure switch or a non-contact photoelectric switch, symmetrically arranged on opposite sides of the spline 101, corresponding to the connection position and decoupling position of the spline 101 respectively, and is used to provide the traction control unit (TCU) with a switch signal characterizing the connection state, decoupling state, neutral state or invalid state of the rail transit transmission safety isolation device 100, so as to ensure that the traction control unit can accurately grasp the working status of the device in real time.

[0039] For example, the position detection switch 105 is symmetrically arranged on the left and right sides of the spline 101, with one side corresponding to the connection position A and the other side corresponding to the decoupling position B. The traction control unit (TCU) monitors the high and low level signals of the switch quantity at the connection position A and the decoupling position B in real time. A high level (1) indicates that the spline 101 is in the corresponding position, and a low level (0) indicates that it is not in the corresponding position. For example, a high level at the connection position A indicates that the spline 101 and the sliding sleeve 102 are in a connected state, and a high level at the decoupling position B indicates that the spline 101 and the sliding sleeve 102 are in a decoupling state.

[0040] The working status of the rail transit transmission safety isolation device 100 can be clearly distinguished by the signal combination of the two position detection switches 105.

[0041] Based on the status signals (1 or 0) of the A and B position detection switches 105, the four working states of the rail transit transmission safety isolation device 100 can be specifically represented as follows: The connection state (transmission engagement) is (1, 0): the switch signal A of the position detection switch 105 is 1 and the switch signal B is 0, indicating that the spline 101 and the sliding sleeve 102 are fully engaged and in the connection position. The power of the permanent magnet motor 210 can be transmitted to the wheel 230 through the spline 101 and the sliding sleeve 102. The decoupling state (transmission isolation) is (0, 1): the switching signal A of the position detection switch 105 is 0 and the switching signal B is 1, indicating that the spline 101 and the sliding sleeve 102 are completely separated and in the decoupling position. The power transmission between the permanent magnet motor 210 and the gearbox 220 or the wheel 230 is interrupted and the power is not connected. In neutral (during the decoupling and restoration of the transmission connection), the signal is (0, 0): the switching signal A of the position detection switch 105 is 0, and the switching signal B is 0, indicating that the spline 101 and the sliding sleeve 102 are in the middle position, neither fully engaged nor fully disengaged, and are in the process of decoupling or restoring the transmission connection. The invalid state (device malfunction) is (1,1): the position detection switch 105 has switch A=1 and switch B=1, which means that both position detection switches 105 detect valid signals at the same time. This is an abnormal state, indicating that the position detection switch 105 or the device itself has malfunctioned.

[0042] The traction control unit (TCU) can identify the above four states in real time. When an invalid state (1, 1) is detected, an alarm signal is immediately output to remind the staff to troubleshoot the fault in time, ensure the reliability of the device status monitoring, and avoid the device from malfunctioning due to the fault.

[0043] In some embodiments, the rail transit transmission safety isolation device 100 further includes a reset mechanism, which is configured to perform a reset operation manually or automatically after the fault is cleared, so as to quickly restore the meshing state of the spline 101 and the sliding sleeve 102, thereby restoring the mechanical transmission connection between the permanent magnet motor 210 and the wheel 230, and ensuring that the train can quickly resume normal operation.

[0044] Optionally, the rail transit transmission safety isolation device 100 preferably has an automatic recovery function, which can automatically complete the reset operation under the control of the traction control unit (TCU); it can also be equipped with a manual recovery function, so that when the automatic reset fails or under special conditions, the staff can manually operate the reset mechanism to complete the device reset, further improving the reliability and emergency response capability of the device, and can be used to quickly rebuild the mechanical transmission connection between the permanent magnet motor 210 and the wheel 230 after the fault is eliminated, shortening the train downtime.

[0045] This rail transit transmission safety isolation device 100 can automatically disconnect the power connection between the motor output shaft 211 of the permanent magnet motor 210 and the wheel axle 231 of the wheel 230 under extreme fault conditions, thereby achieving physical isolation of the faulty permanent magnet motor 210 and preventing the fault from escalating. After the fault is cleared, the device can be reset automatically or manually to quickly rebuild the mechanical transmission link and ensure that the train resumes normal operation.

[0046] This device can completely solve the technical problem that the three-phase isolation contactor of the permanent magnet traction system is difficult to effectively disconnect and reliably isolate faults under extreme fault conditions. After the permanent magnet motor is quickly decoupled, the motor shaft no longer rotates with the wheel, blocking the continuous back electromotive force generated by the permanent magnet motor as a power source from the source, avoiding major safety risks such as overvoltage, arcing, and fire, and greatly improving the operational availability of the traction system in fault scenarios.

[0047] Figure 5 A typical main circuit diagram of a traditional traction electric drive system is shown, such as... Figure 5 As shown, the main circuit of this system uses DC 1500V as the DC input. The traction converter 50 is sequentially configured with a pre-charge circuit 51, a current sensor 52, a reactor 53, a first capacitor 541, a second capacitor 542, a chopper circuit 55, a first inverter module 561, and a second inverter module 562. Each inverter module is equipped with a three-phase isolation output contactor 57 on its three-phase AC output side. The rear end of the contactor is connected to the traction motors PM1 to PM4, respectively. Traditional permanent magnet traction systems use three-phase isolation output contactors at the main circuit output end to achieve electrical isolation under fault conditions, aiming to block the safety risks caused by the back EMF of the permanent magnet motor. However, the contactor has inherent defects such as insufficient breaking capacity and inability to effectively isolate faults under extreme fault conditions.

[0048] Figure 6 A typical main circuit diagram of a traction electric drive system according to an embodiment of the present invention is disclosed, such as... Figure 6As shown, by adopting the rail transit transmission safety isolation device 100 of the present invention, the three-phase isolation output contactor 57 can be eliminated from the main circuit of the traction system. The three-phase AC outputs of the first inverter module 561 and the second inverter module 562 are directly connected to the traction motors PM1~PM4, replacing the traditional electrical isolation method with the mechanical physical isolation of the device. This solution eliminates the three-phase isolation output contactor while retaining the core components of the main circuit such as the pre-charging circuit 51, reactor 53, and inverter module, simplifying the circuit structure, eliminating the hidden danger of contactor disconnection failure, and blocking the continuous back electromotive force generated by the permanent magnet motor as a power source from the source, avoiding safety risks such as overvoltage, arcing, and fire, and significantly improving the protection capability and operational reliability of the traction system under various fault scenarios.

[0049] Based on the above-mentioned rail transit transmission safety isolation device 100, the present invention also provides a traction electric transmission system, including a traction control unit (TCU), a traction motor, a transmission mechanism, and the rail transit transmission safety isolation device 100 as described in any of the foregoing embodiments.

[0050] The traction control unit is connected to the traction motor and is used to control the operation of the traction motor, monitor system faults, and control the operation of the rail transit transmission safety isolation device 100. The traction motor is connected to the rail transit transmission safety isolation device 100 and is used to output power; preferably, the traction motor is a permanent magnet motor 210. The transmission mechanism is connected to the rail transit transmission safety isolation device 100 and is used to transmit power to the wheelset (such as wheel 230); the transmission mechanism may include components such as coupling 240 and gearbox 220; The rail transit transmission safety isolation device 100 is connected on the torque transmission path between the traction motor and the transmission mechanism, serving as a physical connection and disconnection node of the power link. To achieve precise protection in fault scenarios, the traction control unit is configured to execute a fault classification protection strategy, controlling the rail transit transmission safety isolation device 100 to perform corresponding actions according to the degree of fault in the traction system.

[0051] Figure 7 A fault diagnosis and protection logic diagram of a traction electric drive system according to an embodiment of the present invention is disclosed, such as... Figure 7As shown, this invention proposes a targeted fault classification protection strategy, categorizing train traction system faults into three types: minor, moderate, and severe. Based on the severity of each fault, the rail transit transmission safety isolation device 100 is controlled to either remain inactive, activate during a stop, or activate rapidly during operation. The rail transit transmission safety isolation device 100 can efficiently cooperate with the control system of the traction electric transmission system. After the control system issues corresponding commands, it monitors the fault status in real time, achieving hierarchical fault protection and ensuring accurate and effective fault protection.

[0052] The fault classification protection strategy includes: when the fault severity level is a minor fault, controlling the rail transit transmission safety isolation device to remain connected and only reporting the fault; when the fault severity level is a medium fault, controlling the rail transit transmission safety isolation device to reset and re-detect the fault status; when the fault severity level is a severe fault, controlling the rail transit transmission safety isolation device to perform a mechanical decoupling action.

[0053] like Figure 7 As shown, after the train is powered on, the first step is to determine whether the rail transit transmission safety isolation device 100 is in normal condition. If the device is abnormal, the fault is reported to the TCU or the Train Control and Monitor System (TCMS), and ground personnel are alerted to perform maintenance. If the device is normal, the system enters the traction system fault diagnosis and early warning stage. The TCU identifies the severity and type of the fault in real time and determines whether it is a serious fault.

[0054] If the fault is minor in the traction system or a moderate fault unrelated to the permanent magnet motor, the rail transit transmission safety isolation device 100 will not activate, but will only upload the fault information to the TCU or vehicle control system, reminding the train to stop and inspect. Minor faults can be defined as "automatically recoverable faults," requiring no manual intervention and serving only as a warning; moderate faults can be defined as "resetable faults," which can be reset automatically or manually to re-detect the fault status. When the TCU detects an automatically recoverable fault, it will automatically clear the fault if the conditions are met, and resume operation after the fault is cleared; when a resetable fault is detected, it can accept a fault clearing command transmitted via the TCMS.

[0055] If the traction system has a serious fault, the fault type needs to be further identified. A serious fault is defined as an "unresettable fault," which usually requires manual troubleshooting and remedial measures. When an unresettable fault occurs, if power-on reset fails to clear it, the inverter and motor power output must be disconnected, and disconnecting the inverter should not affect the normal operation of inverters in other vehicles.

[0056] For the special cases of the permanent magnet motor 210: If a two-phase short circuit fault occurs in the permanent magnet motor, which is highly dangerous, the motor needs to be controlled to switch to a three-phase short circuit state first. Then, the TCU issues a decoupling command, and the device performs mechanical decoupling to prevent the fault from escalating. If other serious faults such as a three-phase short circuit or inter-turn short circuit occur in the permanent magnet motor, the train is stopped and the motor is re-checked for a serious fault. If a serious fault is confirmed, the TCU issues a decoupling command, and the device performs mechanical decoupling. This strategy can both prevent the two-phase short circuit fault of the permanent magnet motor from worsening and prevent the device from malfunctioning in unnecessary fault scenarios, effectively improving the availability and reliability of the system.

[0057] After the TCU issues a decoupling command, the device executes the decoupling logic. During execution, it needs to determine whether decoupling is complete and whether the status is decoupling (0, 1). If decoupling is complete and the status is correct, the fault is eliminated, the train runs normally, and guidance is provided for decommissioning or returning to the destination. If decoupling is incomplete, the TCU reissues the decoupling command and checks the number of executions. If the number of executions does not exceed a preset threshold (n times), decoupling is re-executed; if the number of executions exceeds n times, the device is deemed to have a decoupling anomaly and is reported to the TCU or vehicle control system.

[0058] If the device itself fails and a two-phase or three-phase short circuit occurs in the motor, the system, prioritizing safety, will default to the device being in a connected state to prevent the fault from escalating further due to an incorrect device status.

[0059] In the above process, the traction control unit controls the power supply voltage and positive / negative output of the drive motor 103, combined with a high-level control signal input (drive decoupling command / reconnection command, DC24V / 110V signal) to issue drive decoupling and reconnection commands. Specifically, controlling the drive motor 103 to rotate forward completes decoupling, and rotating in reverse completes reconnection. The traction control unit ensures that the actuator motor runs smoothly during execution and delays power-off operation for a period of time after recognizing the decoupling or reconnection completion signal to reduce energy consumption.

[0060] During train operation, the TCU monitors the device status in real time and simultaneously detects and predicts faults in the traction system. The decoupling process of the rail transit transmission safety isolation device 100 is only executed when a specific fault requiring power isolation occurs. Furthermore, considering the inherent characteristics of the permanent magnet motor rotor magnetic field, this invention further analyzes fault modes such as permanent magnet demagnetization and motor insulation failure to formulate layered and graded protection measures, preventing faults from affecting train operation. Supported by research on the failure mechanisms of core components, application of fault data analysis, fault simulation, and accelerated life testing, a life prediction model is constructed to achieve fault early warning and prediction.

[0061] It should be noted that reconnection refers to the process of switching the power transmission between the motor and gearbox 220 or wheel 230 from an interrupted state to a connected state. During reconnection, the TCU controls the drive motor 103 to rotate slowly at a constant speed (e.g., 5~20 r / min, which can be set according to actual needs), so that the rail transit transmission safety isolation device 100 is in the connected state. The TCU supplies power to the motor when controlling it to operate, and does not require power supply when it is in other states. It can also identify motor faults, provide protection, and issue alarms. During normal train operation, the rail transit transmission safety isolation device 100 can operate as needed, or it can perform transmission decoupling when the train is at "zero speed" (i.e., the train is stationary, and the speed is 0 km / h). Reconnection operation is usually performed when the motor has no torque and the train speed is 0 km / h, or it can be manually operated to reconnect the mechanical connection.

[0062] Figure 8 A logic diagram illustrating the decoupling process of a rail transit transmission safety isolation device 100 according to an embodiment of the present invention is disclosed, as follows: Figure 8 As shown, the decoupling process specifically includes the following steps: Device status self-check: After the decoupling process is started, a device self-check is first performed to verify whether the device is in a normal state. If the device has a fault (e.g., position detection switch 105 is malfunctioning or drive motor 103 is abnormal), it will directly report to the TCU or vehicle control system and end the process; if the status is normal, it will proceed to the next step to confirm the initial status.

[0063] Initial state confirmation: Confirm whether the device is currently in a connected state, i.e., whether the signal of position detection switch 105 is (1, 0), indicating that spline 101 and sleeve 102 are fully engaged. If the device is not in a connected state, report to the TCU or vehicle control system and end the process; if it is confirmed to be in a connected state, proceed to the next step to perform decoupling action.

[0064] Decoupling action execution: The TCU issues a decoupling command, controls the drive motor 103 to rotate forward, drives the sliding sleeve 102 to move axially along the spline 101, and the rail transit transmission safety isolation device 100 begins to execute the decoupling action.

[0065] During the decoupling process, the system monitors the action time in real time. If the action duration exceeds the preset threshold N seconds, the system determines that the device decoupling is abnormal and reports it to the TCU or vehicle control system; if the timeout does not occur, the system checks whether the device state has switched to the decoupling state, i.e., whether the signal of the position detection switch 105 is (0, 1).

[0066] If a decoupling status signal is detected, the decoupling process is confirmed to be complete, the decoupling command is revoked, and the drive motor 103 stops working. If no decoupling status signal is detected, the device is determined to be decoupling abnormally. When the device decoupling fails, the TCU reissues the decoupling command and accumulates the number of retries. If the number of retries does not exceed the preset threshold n, the decoupling action is executed again (the motor can be reversed for 0.1 seconds to reset, and then forward rotation can be attempted). If the number of retries exceeds n, the device is determined to be faulty (e.g., position detection switch 105 or drive motor 103 fails), the TCU or vehicle control system is notified, and the process ends.

[0067] It should be noted that the threshold n is usually determined based on field tests to ensure that both decoupling and connection can be completed smoothly.

[0068] After the control system issues the corresponding command, it monitors the working status of the device in real time. This device works efficiently with the control system of the traction electric drive system to achieve hierarchical fault protection, ensuring accurate and effective fault protection.

[0069] Figure 9 A logic diagram of the reconnection process of a rail transit transmission safety isolation device according to an embodiment of the present invention is disclosed, such as... Figure 9 As shown, the connection restoration process specifically includes the following steps: Device status self-check: After the reconnection process is started, a device self-check is performed first to verify whether the device is in normal condition. If the device has a fault (e.g., position detection switch 105 is malfunctioning or drive motor 103 is abnormal), it will directly report to the TCU or vehicle control system and end the process; if the status is normal, it will proceed to the next step to confirm the initial status.

[0070] Initial State Confirmation: Confirm whether the device is currently in a decoupled state, i.e., whether the signal of position detection switch 105 is (0, 1), indicating that spline 101 and sleeve 102 are completely disengaged. If the device is in an abnormal state and is not in a decoupled state, report to the TCU or vehicle control system and end the process; if it is confirmed to be in a decoupled state, proceed to the next step to perform the reconnection action.

[0071] Reconnection restoration action execution: The TCU issues a reconnection restoration command, controls the drive motor 103 to reverse, drives the sliding sleeve 102 to move axially along the spline 101, and the rail transit transmission safety isolation device 100 begins to perform the connection action.

[0072] During the reconnection process, the system monitors the action time in real time. If the action duration exceeds a preset threshold of N seconds, the system determines that the device connection restoration is abnormal and reports it to the TCU or vehicle control system; if the timeout does not occur, the system checks whether the device status has switched to the connected state, i.e., whether the signal of the position detection switch 105 is (1, 0).

[0073] If a connection status signal is detected, the connection restoration process is confirmed to be complete, the connection restoration command is cancelled, and the drive motor 103 stops working. If no connection status signal is detected, the device connection restoration is determined to be abnormal.

[0074] When the device connection fails to recover, the TCU reissues the connection recovery command and accumulates the number of retries. If the number of retries does not exceed the preset threshold n, the connection action is executed again (the motor can be rotated forward for 0.1 seconds to reset, and then reversed to try again); if the number of retries exceeds n, the device is determined to be faulty (e.g., position detection switch 105 or drive motor 103 fails), the TCU or vehicle control system is notified, and the process ends.

[0075] It should be noted that the threshold n is usually determined based on field tests to ensure that both decoupling and connection can be completed smoothly.

[0076] In some embodiments, the traction control unit is further configured to execute abnormal handling logic: if no connection status feedback is received within a preset time after issuing a connection restoration command, the drive motor 103 is powered off and reversed to the neutral position, and then the connection restoration command is reissued, and the traction motor is driven to rotate at a predetermined speed to improve the connection success rate.

[0077] Figure 10 A logic diagram for handling abnormal situations during the decoupling process of a rail transit transmission safety isolation device according to an embodiment of the present invention is disclosed, such as... Figure 10 As shown, this process is used to handle timeouts or state anomalies that occur during decoupling. The specific steps are as follows: First, the device is currently in a connected state. If an abnormal connection is detected (e.g., both position detection switches 105 are simultaneously 1 or simultaneously 0), a device fault is directly reported and the process ends. If a normal connection is detected, i.e., the position detection switch 105 signal is (1,0), the TCU issues a decoupling command to control the drive motor 103 to rotate forward. The system begins monitoring the decoupling process and checks whether it enters the decoupling state (0,1) within a preset time N seconds. If (0,1) is successfully detected within N seconds, the decoupling is completed normally, the drive motor 103 is de-energized, and the process ends.

[0078] If no decoupling state is detected after N seconds, an exception handling procedure is triggered: first, the motor is reversed to reset, then it is rotated forward to attempt re-decoupling, while accumulating the number of retries. Next, it is determined whether the number of retries has exceeded a preset threshold of n times: if it has not exceeded n times, the above retry and reset operation continues; if it has exceeded n times, it is determined to be a device malfunction, and the TCU or vehicle control system is notified, and the process ends.

[0079] Figure 11A logic diagram for handling abnormal situations during the reconnection process of a rail transit transmission safety isolation device according to an embodiment of the present invention is disclosed, such as... Figure 11 As shown, this process is used to handle timeouts or status anomalies that occur during connection recovery. The specific steps are as follows: First, the device is currently in a decoupled state. If an abnormal decoupling state is detected (e.g., both position detection switches 105 are simultaneously 1 or simultaneously 0), a device fault is directly reported and the process ends. If a normal decoupling state is detected, i.e., the position detection switch 105 signal is (0,1), the TCU issues a reconnection command, controlling the drive motor 103 to reverse. The system begins monitoring the reconnection process and checks whether it enters a connected state (1,0) within a preset time N seconds. If (1,0) is successfully detected within N seconds, the reconnection is successfully completed, the drive motor 103 is de-energized, and the process ends.

[0080] If no connection is detected after N seconds, an error handling process is triggered: first, the motor is controlled to rotate forward to reset, then reversed to attempt reconnection. The traction motor is driven to rotate slowly at a certain speed (adjustable) to assist the spline 101 and the sliding sleeve 102 in alignment and engagement, improving the connection success rate, while accumulating the number of retries. Next, it is determined whether the number of retries has exceeded the preset threshold n times: if it has not exceeded n times, the above retry and reset operation continues; if it has exceeded n times, it is determined to be a device malfunction, and the TCU or vehicle control system is reported, and the process ends.

[0081] It should be noted that if the attempt fails after multiple retries, it can be determined that the position detection switch 105 or the drive motor 103 has failed, causing a feedback transmission isolation device malfunction to the TCU or the train control system TCMS. Thresholds N and n are usually determined based on field tests to ensure successful decoupling and connection.

[0082] Figure 10 and Figure 11 The abnormal handling logic effectively solves the problem of action failure caused by mechanical jamming, misalignment and other reasons through power failure reset, forward and reverse adaptive adjustment and limited retry mechanism, thereby improving the reliability and self-recovery capability of the rail transit transmission safety isolation device 100.

[0083] In some embodiments, the traction control unit is further configured with power-on self-test logic: Each time the train is powered on, the control system of the rail transit transmission safety isolation device sequentially performs connection status detection, decoupling action and connection restoration action to complete the full process verification; If any step is abnormal, the system will try again a preset number of times. If the problem persists, a self-test fault alarm will be output.

[0084] For example, the train performs a power-on self-test before leaving the depot each day. Each time power is applied, the entire process of "connection status detection—decoupling—neutral—reconnection restoration—connection status detection" is actively executed. After this process is completed, the device's drive motor 103 is de-energized, the transmission structure remains connected, and the train's traction system operates normally. During the self-test, if any step is abnormal, and the abnormality persists after n attempts, the corresponding fault is reported to the TCU or the train control system TCMS, prompting ground personnel to conduct a pre-departure inspection.

[0085] An exemplary power-on self-test logic includes the following steps: The current status of the rail transit transmission safety isolation device 100 is detected. If it is in the "connected position", that is, the position detection switch 105 signal is (1,0), then the TCU issues a decoupling command. The rail transit transmission safety isolation device 100 performs a decoupling action. After detecting the "decoupling position" within a preset time, that is, after the position detection switch 105 signal is (0,1), it issues a reconnection command. The rail transit transmission safety isolation device 100 performs a connection action, detects the "connection position" within a preset time, confirms that the self-check is completed, and can depart normally; If any step is abnormal, the step should be retried; if it is still abnormal after n attempts, a fault should be reported and a pre-shipment check should be performed. At the same time, the system should be able to identify self-test abnormalities and issue an alarm.

[0086] It should be noted that the threshold n is usually determined based on field tests to ensure that both decoupling and connection can be completed smoothly.

[0087] Based on the above-described traction electric drive system, the present invention also provides a rail transit transmission safety isolation control method, applied to the traction electric drive system described in any of the foregoing embodiments, comprising the following steps: After the train is powered on, the traction control unit (TCU) controls the rail transit transmission safety isolation device 100 to perform a power-on self-test, completing the full-process verification of connection status detection, decoupling action and reconnection action; The traction control unit monitors the fault status of the traction system and the position status of the rail transit transmission safety isolation device 100 (i.e., the signal combination of the position detection switch 105) in real time. Based on the severity level of the traction system fault, a fault classification protection strategy is implemented, and the rail transit transmission safety isolation device 100 is controlled to perform corresponding maintaining connection, reset, or mechanical decoupling actions. After the fault is cleared, the traction control unit controls the rail transit transmission safety isolation device 100 to reset, restoring the mechanical transmission connection between the traction motor and the wheelset.

[0088] During train operation, the traction control unit monitors system faults and device status in real time, and only performs decoupling actions in fault scenarios that require power isolation, thereby achieving precise and effective fault protection and comprehensively improving the operational safety and reliability of the permanent magnet traction system for rail transit.

[0089] Although the methods described above are illustrated and depicted as a series of actions for the sake of simplicity, it should be understood and appreciated that these methods are not limited by the order of the actions, as some actions may occur in a different order and / or concurrently with other actions from the illustrations and descriptions herein or not illustrated and described herein but which may be understood by those skilled in the art, according to one or more embodiments.

[0090] This invention provides a rail transit transmission safety isolation device, a matching traction electric transmission system, and a corresponding control method. By integrating a mechanical transmission safety isolation device into the torque transmission path between the traction motor and the gearbox, and between the gearbox and the wheel axle, the device can quickly disconnect the mechanical transmission link under extreme fault conditions, isolate the faulty permanent magnet motor, and quickly reset after the fault is cleared, ensuring the continuous safe operation of the train. Under fault conditions, the permanent magnet motor shaft can be quickly decoupled from the wheel set and no longer rotates with the wheel, avoiding the safety risks caused by back electromotive force from the source. This completely solves the problem of traditional three-phase isolation contactors failing under extreme conditions. At the same time, through a hierarchical fault protection strategy, it avoids device malfunction and comprehensively improves the safety, reliability, and availability of the rail transit permanent magnet traction system under fault scenarios.

[0091] The present invention provides a safety isolation device for rail transit transmission, a matching traction electric transmission system, and a corresponding control method, which have the following beneficial effects: 1) The mechanical output of the permanent magnet motor can be quickly disconnected, so that the motor no longer rotates with the wheel, thereby avoiding the generation of back EMF. This completely solves the problem that the three-phase isolation contactor is difficult to effectively disconnect and cannot reliably achieve fault isolation under extreme fault conditions. It effectively blocks the safety risks such as overvoltage, arcing, and fire caused by the continuous back EMF when the permanent magnet motor is used as a power source, and significantly improves the availability of the traction system under various fault scenarios. 2) The main circuit of the permanent magnet traction system can eliminate the three-phase isolation output contactor, and replace the traditional electrical isolation with mechanical physical isolation, which simplifies the circuit structure while avoiding the risk of electrical isolation failure; 3) This device works efficiently with the control system of the traction electric drive system to achieve hierarchical fault protection and ensure accurate and effective fault isolation; 4) For typical faults (such as two-phase short circuit, three-phase short circuit, etc.), it can effectively prevent the two-phase short circuit fault of permanent magnet motor from escalating, and avoid misdiagnosis of minor faults or serious faults such as three-phase short circuit, inter-turn short circuit, etc., which may lead to device malfunction, thereby improving system availability and reliability. 5) In the event of a fault in the device itself, the system adopts a safety-oriented protection strategy, which defaults to the device being in a connected state to prevent the fault from escalating further due to the device's incorrect state, and to ensure that the train can be safely handled in a timely manner.

[0092] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not specifically singular and may include plural forms. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0093] Those skilled in the art will further appreciate that the various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments disclosed herein can be implemented as electronic hardware, computer software, or a combination of both. To clearly illustrate this interchangeability between hardware and software, the various illustrative components, blocks, modules, circuits, and steps are described above in a generalized manner in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in different ways for each specific application, but such implementation decisions should not be construed as departing from the scope of the invention.

Claims

1. A safety isolation device for rail transit transmission, characterized in that, Installed on the torque transmission path between the traction motor and the wheelset, including splines, sliding sleeves, drive motors, lead screw mechanisms, and position detection switches: The spline is used to connect with the output shaft of the traction motor, and the sliding sleeve is used to connect with the input shaft of the wheelset. The spline and the sliding sleeve are slidably engaged. The mechanical transmission connection between the traction motor and the wheelset is established or decoupled by the movement of the sliding sleeve along the axial direction of the spline. The drive motor is connected to the lead screw mechanism, and the lead screw mechanism is connected to the sliding sleeve, for driving the sliding sleeve to move; The position detection switch is used to detect the connection or decoupling status of the spline and the sliding sleeve.

2. The rail transit transmission safety isolation device according to claim 1, characterized in that, The torque transmission path includes the traction motor and coupling, the coupling and gearbox, the wheel axle and gearbox, or the traction motor and wheel axle.

3. The rail transit transmission safety isolation device according to claim 1, characterized in that, The lead screw mechanism is a planetary roller lead screw, and the planetary roller lead screw achieves self-locking when the drive motor stops rotating.

4. The rail transit transmission safety isolation device according to claim 1, characterized in that, The spline and the sliding sleeve are mechanically limited by a groove to prevent miscoupling of the mechanical transmission connection during vehicle operation.

5. The rail transit transmission safety isolation device according to claim 1, characterized in that, The position detection switch is a contact pressure switch or a non-contact photoelectric switch, and is disposed on opposite sides of the spline to provide a switch signal characterizing the connection state, decoupling state, neutral state, or invalid state.

6. The rail transit transmission safety isolation device according to any one of claims 1 to 5, characterized in that, It also includes a reset mechanism configured to restore the mechanical transmission connection between the traction motor and the wheelset by resetting manually or automatically after the fault has been cleared.

7. A traction electric drive system, characterized in that, It includes a traction control unit, a traction motor, a transmission mechanism, and a rail transit transmission safety isolation device as described in any one of claims 1 to 6; The traction control unit is connected to the traction motor and is used to control the operation of the traction motor, monitor system faults, and control the operation of the rail transit transmission safety isolation device. The traction motor is connected to the rail transit transmission safety isolation device and is used to output power; The transmission mechanism is connected to the rail transit transmission safety isolation device and is used to transmit power to the wheelset; The rail transit transmission safety isolation device is connected between the traction motor and the transmission mechanism; The traction control unit is configured to implement a fault classification protection strategy: based on the fault level of the traction system, it controls the rail transit transmission safety isolation device to perform corresponding actions.

8. The traction electric drive system according to claim 7, characterized in that, The fault classification protection strategy includes: When the fault severity level is minor, the rail transit transmission safety isolation device is kept connected and only reports the fault. When the fault severity level is medium, the rail transit transmission safety isolation device is reset and the fault status is re-detected. When the fault severity level is a severe fault, the rail transit transmission safety isolation device is controlled to perform a mechanical decoupling action.

9. The traction electric drive system according to claim 7, characterized in that, The traction motor is a permanent magnet motor; The traction control unit is also configured to: For a two-phase short-circuit fault in a permanent magnet motor, the control first switches to a three-phase short circuit before executing the mechanical decoupling action of the rail transit transmission safety isolation device. For three-phase short circuit or inter-turn short circuit faults in permanent magnet motors, the mechanical decoupling action of the rail transit transmission safety isolation device is executed after the train stops and the fault is reconfirmed.

10. The traction electric drive system according to claim 7, characterized in that, The traction control unit is also configured to execute exception handling logic: If no connection status feedback is received within a preset time after issuing the reconnection command, the drive motor is powered off and reversed to the neutral position. Then, the reconnection command is issued again, and the traction motor is driven to rotate at a predetermined speed.

11. The traction electric drive system according to claim 7, characterized in that, The traction control unit is also configured with power-on self-test logic: Each time the train is powered on, the control system of the rail transit transmission safety isolation device sequentially performs connection status detection, decoupling action and connection restoration action to complete the full process verification; If any step is abnormal, the system will try again a preset number of times. If the problem persists, a self-test fault alarm will be output.

12. A method for safety isolation control of rail transit transmission, applied to the traction electric transmission system according to any one of claims 7 to 11, characterized in that, Includes the following steps: After the train is powered on, the traction control unit controls the rail transit transmission safety isolation device to perform a power-on self-test, completing the full-process verification of connection status detection, decoupling action and reconnection action; The traction control unit monitors the fault status of the traction system and the position status of the rail transit transmission safety isolation device in real time. Based on the severity level of the traction system fault, a fault classification protection strategy is implemented to control the rail transit transmission safety isolation device to perform corresponding actions; After the fault is cleared, the traction control unit resets the rail transit transmission safety isolation device, restoring the mechanical transmission connection between the traction motor and the wheelset.

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