Redundant fault protection device, method and system for permanent magnet traction system and medium

Abstract

The invention discloses a redundant fault protection device, method and system for a permanent magnet traction system and a medium, relates to the field of rail transit traction systems, and provides the redundant fault protection device for the permanent magnet traction system in order to solve the problem that reliability and safety are insufficient when counter electromotive force generated by a permanent magnet traction motor is isolated through an isolation contactor at present. And counter potential isolation control of two-stage redundancy is realized through the excitation fuse and the isolation contactor. In addition, the excitation fuses and the isolation contactors are disposed in separate contactor boxes. When the isolation contactor generates electric arc or even is on fire due to overlarge current of the traction converter, the fire behavior can be effectively controlled within a certain range through the isolator box, and the safety of a train traction system is further guaranteed. Moreover, the excitation fuse can achieve the controllable rapid protection of a TCU signal based on the characteristics of the fuse. The possibility that the isolation contactor is on fire due to large current can be reduced, and the safety of a train traction system is further improved.

Description

Technical Field

[0001] This application relates to the field of rail transit traction systems, and in particular to a redundancy fault protection device, method, system and medium for a permanent magnet traction system. Background Technology

[0002] Permanent magnet traction systems, as the development direction of next-generation high-speed trains and high-power AC drive locomotive traction systems, are a focal point of rail transit vehicle technology. However, their application currently faces many challenges. For example, when the permanent magnet traction motor is not powered but the rotor continues to rotate, it generates back electromotive force (EMF). This back EMF increases the difficulty of system control and protection measures.

[0003] Therefore, a common practice is to install an isolating contactor between the traction converter and the permanent magnet traction motor to isolate the back EMF generated by the permanent magnet traction motor. However, this solution cannot effectively isolate the back EMF if the isolating contactor itself malfunctions, or if a short circuit within the traction converter causes excessive current, preventing the contactor from disconnecting. Furthermore, disconnecting the contactor while it is energized or when there is a short circuit within the converter can easily generate an electric arc. Especially when the permanent magnet traction motor continuously generates a back EMF, there is a risk of the isolating contactor catching fire, affecting the safety of the traction converter, the permanent magnet traction motor, and the entire vehicle.

[0004] Therefore, those skilled in the art urgently need a redundant fault protection device for permanent magnet traction systems to solve the problem of insufficient reliability and safety of the back EMF generated by the permanent magnet traction motor currently isolated by an isolating contactor. Summary of the Invention

[0005] The purpose of this application is to provide a redundant fault protection device, method, system and medium for permanent magnet traction systems, so as to solve the problem of insufficient reliability and safety of the back EMF generated by permanent magnet traction motors currently isolated by isolating contactors.

[0006] To address the aforementioned technical problems, this application provides a redundant fault protection device for a permanent magnet traction system, comprising: an isolation contactor, an excitation fuse, a contactor box, a current detection unit, and a control unit;

[0007] The isolating contactor and the excitation fuse are disposed in the contactor box, and the isolating contactor and the excitation fuse are connected in series between the traction converter and the permanent magnet traction motor.

[0008] The current detection unit is connected to the three-phase output terminal of the inverter in the traction converter and is used to detect the three-phase current.

[0009] The control unit is connected to the current detection unit, the isolation contactor, and the excitation fuse, and is used to control the on / off state of the isolation contactor and the excitation fuse according to the three-phase current.

[0010] In one optional embodiment, it further includes: a fire detection unit;

[0011] The fire detection unit is installed inside the contactor box and connected to the control unit, and is used to detect whether a fire has started inside the contactor box;

[0012] The control unit is also configured to: when the fire detection unit detects a fire in the contactor box, control the isolating contactor and the excitation fuse to turn off.

[0013] In one optional embodiment, the fire detection unit includes: a heat-sensing cable and a smoke detector;

[0014] The temperature-sensing cable is used to detect the temperature inside the contactor box;

[0015] The smoke detector is used to detect the smoke concentration inside the contactor box;

[0016] The control unit is also used to determine whether a fire has started inside the contactor box based on the temperature detected by the temperature sensing cable and the smoke concentration detected by the smoke detector.

[0017] In one optional embodiment, the current detection unit is the output current sensor in the traction converter, and the control unit is the traction control unit in the traction converter;

[0018] The traction control unit is connected via a hard wire to the isolating contactor and the excitation fuse located in the contactor box.

[0019] In one alternative embodiment, the inner and outer surfaces of the contactor box are provided with fire-resistant layers.

[0020] In one alternative embodiment, the contactor box is positioned close to the permanent magnet traction motor.

[0021] In one optional embodiment, the number of permanent magnet traction motors is multiple;

[0022] There are multiple contactor boxes, each corresponding to a permanent magnet traction motor; each contactor box is located close to the bogie where the corresponding permanent magnet traction motor is located.

[0023] To solve the above-mentioned technical problems, this application also provides a method for redundancy fault protection of a permanent magnet traction system, which is applied to the permanent magnet traction system redundancy fault protection device as described above.

[0024] The methods include:

[0025] Determine if the isolating contactor is experiencing a failure to disconnect;

[0026] If this occurs, the three-phase current output from the inverter in the traction converter is obtained;

[0027] If the three-phase currents meet the fault conditions, the control excitation fuse will be opened.

[0028] In one optional embodiment, determining whether the isolating contactor has a failure to disconnect includes:

[0029] Send a disconnect command to the isolation contactor;

[0030] If no status information is received from the isolating contactor within a preset time, or if the received status information does not indicate that the isolating contactor is in an open state, then it is determined that the isolating contactor has a failure to disconnect.

[0031] In an optional embodiment, when the three-phase currents meet the fault conditions, the method further includes:

[0032] The inverter is locked down, and a stop inspection request is sent to the train control unit.

[0033] In an optional embodiment, after acquiring the three-phase current output from the inverter in the traction converter, the method further includes:

[0034] If the three-phase current does not meet the fault conditions, the inverter is controlled to be locked and a fault information that the contactor cannot be disconnected is reported to the train control unit.

[0035] In an optional embodiment, the permanent magnet traction system redundancy fault protection device further includes: a temperature sensing cable and a smoke detector; the temperature sensing cable is used to detect the temperature inside the contactor box; the smoke detector is used to detect the smoke concentration inside the contactor box.

[0036] The method also includes:

[0037] When a fire is determined to have occurred inside the contactor box based on the temperature detected by the temperature sensing cable or the smoke concentration detected by the smoke detector, the system controls the disconnection of the isolating contactor and the excitation fuse, controls the inverter to be locked, and sends a stop inspection request to the train control unit.

[0038] To solve the above-mentioned technical problems, this application also provides a redundancy fault protection system for a permanent magnet traction system, which is applied to the redundancy fault protection device for the permanent magnet traction system as described above.

[0039] The system includes:

[0040] The detection module is used to determine whether the isolating contactor has a failure to disconnect.

[0041] The acquisition module is used to acquire the three-phase current output by the inverter in the traction converter if the condition is met.

[0042] The protection module is used to control the excitation fuse to open if the three-phase current meets the fault conditions.

[0043] To address the aforementioned technical problems, this application also provides a redundant fault protection system for a permanent magnet traction system, comprising:

[0044] Memory, used to store computer programs;

[0045] A processor is used to implement the steps of the permanent magnet traction system redundancy fault protection method as described above when executing the computer program.

[0046] To address the aforementioned technical problems, this application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the redundancy fault protection method for a permanent magnet traction system as described above.

[0047] This application provides a redundant fault protection device for a permanent magnet traction system, comprising an isolating contactor, a pyrofuse, a contactor box, a current detection unit, and a control unit. The isolating contactor and the pyrofuse are connected in series between the traction converter and the permanent magnet traction motor. The isolating contactor also provides back EMF isolation. The pyrofuse, as a redundant device of the isolating contactor, can disconnect the path between the traction converter and the permanent magnet traction motor when the isolating contactor cannot be disconnected, thereby achieving back EMF isolation. Therefore, this application achieves a redundant design for back EMF isolation based on the pyrofuse, ensuring effective isolation of back EMF even when the isolating contactor cannot be disconnected. Furthermore, the isolating contactor and pyrofuse in this device are independently located within the contactor box, separate from the traction converter. This ensures that even if the isolating contactor arcs and catches fire under special circumstances, the fire can be contained within the contactor box, preventing damage to critical equipment such as the traction converter and the permanent magnet traction motor, further improving train operation safety.

[0048] Furthermore, this device selects an excitation fuse as a redundant device for the isolating contactor. On one hand, excitation fuses are low-cost and small in size, and the implemented redundancy design does not significantly increase the cost of the back EMF isolation scheme or the space occupied by the train. On the other hand, although the excitation fuse is mainly controlled by the control unit, as a type of fuse, it possesses the characteristics of a fuse and can provide overcurrent protection. Therefore, when the isolating contactor disconnects while energized or when there is a short circuit inside the converter, the fuse will melt due to the large current in the circuit, promptly and effectively ensuring the connection between the traction converter and the permanent magnet traction motor is broken, avoiding further losses caused by back EMF.

[0049] The redundancy fault protection method, system, and computer-readable storage medium for permanent magnet traction systems provided in this application correspond to the aforementioned device and have the same effect. Attached Figure Description

[0050] To more clearly illustrate the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 This is a structural diagram of a redundancy fault protection device for a permanent magnet traction system provided in an embodiment of the present invention;

[0052] Figure 2 A circuit diagram of a redundancy fault protection device for a permanent magnet traction system provided in an embodiment of the present invention;

[0053] Figure 3 A circuit schematic diagram of a control unit and a contactor box communicating via a network, provided for an embodiment of the present invention;

[0054] Figure 4 A circuit diagram of multiple inverters and a permanent magnet traction motor provided for an embodiment of the present invention;

[0055] Figure 5 A flowchart of a redundancy fault protection method for a permanent magnet traction system provided in an embodiment of the present invention;

[0056] Among them, 10 is the contactor box, 11 is the isolating contactor, 12 is the excitation fuse, 13 is the temperature sensing cable, 14 is the smoke detector, 20 is the traction converter, 21 is the current detection unit, 22 is the control unit, 23 is the inverter, and 30 is the permanent magnet traction motor. Detailed Implementation

[0057] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this application.

[0058] The core of this application is to provide a redundancy fault protection device, method, system, and medium for a permanent magnet traction system.

[0059] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0060] The rotor of a permanent magnet traction motor uses permanent magnets. Therefore, even when the permanent magnet traction motor is not powered but the rotor is still rotating, the permanent magnets can still generate alternating magnetic flux. At this time, even if the power supply is disconnected in time, the stator windings of the permanent magnet traction motor can still induce a back electromotive force (EMF) and cannot be turned off. The appearance of the back EMF increases the difficulty of system control and protection measures, and must be addressed.

[0061] In related technologies, back EMF is mainly isolated by installing an isolation contactor between the traction converter and the permanent magnet traction motor. When back EMF is generated, the isolation contactor is controlled to disconnect the path between the traction converter and the permanent magnet traction motor, thus isolating the back EMF at its source and preventing it from affecting the rest of the train traction system.

[0062] However, the above solution relies excessively on the isolating contactor. When the isolating contactor malfunctions and fails to shut off, it cannot effectively isolate the back EMF. For example, the isolating contactor itself may malfunction and fail to disconnect. Alternatively, a short circuit within the traction converter causing excessive current may also prevent the isolating contactor from disconnecting. Furthermore, disconnecting the isolating contactor while it is energized, or disconnecting it when there is a short circuit within the traction converter causing excessive current, can easily generate an electric arc. Especially when the permanent magnet traction motor continuously generates a back EMF, the continuously generated arc can easily pose a fire risk. In particular, since the isolating contactor, as a device for isolating the back EMF between the permanent magnet traction motor and the traction converter, is usually integrated into the traction converter in practical applications, the arc generated by the isolating contactor can easily cause the traction converter to catch fire, leading to serious losses and safety problems.

[0063] To address the aforementioned problems, this application provides a redundant fault protection device for a permanent magnet traction system. For example... Figure 1 As shown, it includes: an isolating contactor, an excitation fuse (Pyrofuse), a contactor box, a current detection unit, and a control unit.

[0064] The isolating contactor and the excitation fuse are housed within the contactor box and connected in series between the traction converter and the permanent magnet traction motor. The current detection unit is connected to the three-phase output terminals of the inverter in the traction converter to detect the three-phase current. The control unit is connected to the current detection unit, the isolating contactor, and the excitation fuse to control the on / off state of the isolating contactor and the excitation fuse based on the three-phase current.

[0065] Regarding the aforementioned isolating contactor, this embodiment does not limit its specific type, model, specifications, or other specific implementation methods. Similarly, this embodiment does not limit the control scheme used to achieve back EMF isolation for the isolating contactor. Since related technologies achieve back EMF isolation through isolating contactors, there must exist a control scheme for achieving back EMF isolation with isolating contactors, and this control scheme can be used to implement the control of the isolating contactor in this embodiment.

[0066] Pyrofuse, a type of fuse, possesses the general characteristics of a fuse. For example, it melts when the current flowing through it exceeds the fusing current, thus breaking the circuit. However, pyrofuse offers "precise protection." Unlike the passive protection of traditional fuses that "blow when the current exceeds a threshold," pyrofuse is an actively triggered device. Through software triggering and logical judgment, it can dynamically decide whether to trigger protection. This effectively resolves the contradiction between operating current and protection current, achieving precise control by "analyzing and determining whether to disconnect protection based on actual conditions." For example, in a train traction system scenario, the surge current during rapid vehicle acceleration will not trigger protection; however, in the event of a collision, short circuit, or receiving a control signal from the control unit, it will generate high-pressure gas through an internal igniter upon receiving the control signal, physically breaking the circuit to achieve protection disconnection. This "breaking when it should break, and not breaking when it shouldn't" characteristic resolves the contradiction of traditional fuses that are either "falsely triggered or not timely enough." In addition, the activated fuse can be reset after the protection is triggered, unlike traditional fuses such as regular fuses which cannot be reset after blowing.

[0067] Regarding the control of the excitation fuse, on the one hand, one of the core functions of the excitation fuse in this device is to serve as a redundant setting for the isolating contactor. Therefore, under normal conditions (i.e., when the isolating contactor and related controls are functioning normally), the excitation fuse can maintain synchronous on / off states with the isolating contactor. That is, the control devices or control signals originally used to control the isolating contactor also produce the same control effect on the excitation fuse.

[0068] On the other hand, this embodiment also includes a current detection unit and a control unit. The current detection unit detects the three-phase current output by the inverter in the traction converter. As explained in the above-mentioned technical section, besides the inability of the isolation contactor to effectively isolate back EMF due to its own fault, another major factor is that the traction converter may have a short circuit point causing excessive current, leading to the isolation contactor attempting to disconnect while energized. However, this energized disconnection may fail to complete. Therefore, this device uses a current detection unit to detect the three-phase current output by the inverter in the traction converter; the control unit then determines whether the current is excessive based on the three-phase current. When the current is excessive, the isolation contactor may fail to disconnect. In this case, the back EMF can be isolated by controlling the excitation fuse to open.

[0069] Furthermore, although the control unit controls the excitation fuse to open when it determines that the three-phase current is too high, its purpose is to ensure back EMF isolation even if the isolating contactor cannot disconnect. However, an excessive three-phase current does not necessarily mean that the isolating contactor cannot disconnect normally. Moreover, the isolating contactor and the excitation fuse are connected in series, making them redundant switching devices. Therefore, to avoid potential malfunctions of the excitation fuse, the isolating contactor also needs to be switched off synchronously. Additionally, when the three-phase current is too high, the circuit also needs to be cut off for the protection of the circuit and downstream devices (permanent magnet traction motor). In this case, redundant disconnection control through the isolating contactor and the excitation fuse further ensures safety.

[0070] This embodiment does not impose any restrictions on the specific implementation of the current detection unit and the control unit. The current detection unit can be implemented using a current acquisition circuit, a current sensor, or a hardware solution that indirectly acquires current by acquiring voltage. The control unit can be implemented using control devices such as a microcontroller unit (MCU), and this embodiment does not impose any restrictions on this.

[0071] However, this application provides an optional embodiment:

[0072] The aforementioned current detection unit is the output current sensor in the traction converter, and the control unit is the traction control unit in the traction converter. The traction control unit is connected via a hard wire to the isolating contactor and the excitation fuse located in the contactor box.

[0073] In other words, the implementation scheme provided in this embodiment reuses the output current sensor in the traction converter as the current detection unit in this device, and reuses the traction control unit (TCU) in the traction converter as the control unit in this device. This achieves the effect of avoiding the need for additional components, reducing the cost, space occupation, and wiring difficulty of this device, thus avoiding adverse factors affecting actual implementation.

[0074] like Figure 2 As shown, in current train traction systems, current sensors are installed in the traction converter. Figure 2 The current sensor (CV) in the inverter detects the three-phase current at the three-phase output terminals, i.e., the output current sensor. It works in conjunction with the train's TCU to achieve traction control. Furthermore, since the current detection unit and control unit are existing components in the traction converter in this embodiment, while the isolation contactor and excitation fuse are located in the contactor box, this embodiment uses hard wiring to establish a communication connection between the control unit and the isolation contactor and excitation fuse to ensure the transmission of control signals, thus enabling effective control of the isolation contactor and excitation fuse by the control unit.

[0075] However, it should be noted that the above is only one possible embodiment. Current train TCUs typically also support network communication. Therefore, as... Figure 3 As shown, the TCU can also achieve effective control by communicating with the isolating contactor and the excitation fuse located in the contactor box via a network control system. In addition, by adding corresponding communication units, the TCU can also communicate with the isolating contactor and the excitation fuse through other wired or wireless communication methods; this embodiment does not impose any limitations on this.

[0076] On the other hand, regarding the contactor box, its purpose is to physically isolate the contactor, excitation fuse, and other components in the train traction system. Furthermore, its primary purpose is to prevent the fire from spreading to other components in the train traction system should the isolating contactor catch fire. In addition, the contactor box also protects the components within it. Therefore, contactor boxes can be made of high-temperature resistant and high-strength materials such as stainless steel and aluminum alloy.

[0077] Furthermore, to improve the fire resistance of the contactor box, this embodiment also provides an optional implementation: the inner and outer surfaces of the contactor box are provided with fire-resistant layers.

[0078] It should be noted that this embodiment does not limit the specific implementation of the fireproof layer. For example, the fireproof layer can be achieved by attaching fire-retardant material to the surface of the contactor box or by spraying fire-retardant paint to form a fire-retardant paint layer. The fireproof layer further improves the fire resistance of the contactor box. It ensures that when the isolating contactor inside the contactor box catches fire due to continuous arcing, the fire will not affect important components such as the traction converter and permanent magnet traction motor, ensuring train safety and preventing losses. Furthermore, this embodiment provides a double-layer fireproof layer for the contactor box, both inside and out, which further enhances the fire resistance.

[0079] Furthermore, this embodiment does not impose restrictions on the location of the contactor box. Since the isolating contactor and excitation fuse in the contactor box are connected in series between the traction converter and the permanent magnet traction motor, the contactor box should also be physically located between the traction converter and the permanent magnet traction motor to avoid unnecessary wiring. However, this embodiment further provides an optional setting scheme for the physical location of the contactor box: the contactor box is located close to the permanent magnet traction motor.

[0080] It should be noted that although the isolating contactor and excitation fuse in this device are connected in series between the traction converter and the permanent magnet traction motor in terms of circuit connection, their physical location is within the contactor, not integrated into the traction converter or permanent magnet traction motor. Therefore, when implementing the circuit connection, a portion of the cable needs to be led out from the traction converter and permanent magnet traction motor. As explained above, one of the core purposes of the isolating contactor and excitation fuse is to isolate the back EMF at its source, i.e., the permanent magnet traction motor side. If the cable leading from the permanent magnet traction motor connects to the isolating contactor and excitation fuse, this portion of the cable is also included in the "source" range. Therefore, to avoid the expansion of the back EMF range, this embodiment places the contactor box close to the permanent magnet traction motor, minimizing the length of the connecting cable between them, thereby reducing the expansion range of the back EMF and ensuring the isolation effect.

[0081] Furthermore, this application does not limit the specific number of devices such as isolating contactors, excitation fuses, current detection units, and control units. It is clear from the above that isolating contactors and excitation fuses specifically achieve back EMF isolation by disconnecting the three-phase output of the inverter in the traction converter from the permanent magnet traction motor. Therefore, each isolating contactor and excitation fuse corresponds one-to-one with a permanent magnet traction motor. That is, for each permanent magnet traction motor, a corresponding set of isolating contactors and excitation fuses should be installed. In the train traction system scenario, permanent magnet traction motors are typically mounted on bogies and correspond one-to-one with each bogie. Simultaneously, because the isolating contactors and excitation fuses are housed in contactor boxes; the contactor boxes prevent the spread of fire to other devices in the event of a fire in the isolating contactor; and different sets of isolating contactors and excitation fuses are used to achieve back EMF isolation between different inverters and permanent magnet traction motors; therefore, different sets of isolating contactors and excitation fuses should be housed in different contactor boxes.

[0082] That is, this embodiment provides an optional implementation scheme, such as... Figure 4 As shown: there are multiple permanent magnet traction motors; there are multiple contactor boxes, each corresponding to a permanent magnet traction motor; each contactor box is located close to the bogie where the corresponding permanent magnet traction motor is located.

[0083] It should be noted that, Figure 4 The diagram shows only one possible scenario. The traction converter includes two sets of rectifiers (4QS) and inverters (INV), each connected to a different permanent magnet traction motor. In this case, two contactor boxes should be installed, each containing an isolation contactor and an excitation fuse to isolate the back EMF generated by the corresponding permanent magnet traction motor.

[0084] Furthermore, regarding the current detection unit and control unit, as in one optional embodiment described above, the current detection unit can reuse the existing output current sensor in the traction converter. The output current sensor is a current sensor located at the three-phase output terminal of the inverter to detect the three-phase current of the inverter. The TCU requires the detection of the three-phase current for each inverter. Therefore, for each inverter in the traction converter, there will be a corresponding set of output current sensors, i.e., one current detection unit as described above. However, for the simple task of receiving the current value obtained by the current detection unit and performing a simple judgment, commonly used control devices such as MCUs or the aforementioned reusable TCUs support the execution of multiple tasks. Therefore, the control unit does not need to be configured to correspond one-to-one with each inverter; as long as the control requirements are met, only one control unit is needed.

[0085] For example, such as Figure 4This illustrates one possible scenario. Each of the three-phase output terminals of both inverters is equipped with a set of output current sensors, serving as the aforementioned current detection units. That is, the number of current detection units corresponds to the number of inverters. Only one control unit, implemented using a multiplexed TCU, is needed, communicating with each current detection unit and the isolation contactors and excitation fuses in each contactor box.

[0086] Furthermore, this application also provides an optional embodiment. The above-mentioned device further includes: a fire detection unit. The fire detection unit is disposed inside the contactor box and connected to the control unit, and is used to detect whether a fire has occurred inside the contactor box. The control unit is also used to: control the isolating contactor and the excitation fuse to turn off when the fire detection unit detects a fire inside the contactor box.

[0087] By installing a fire detection unit inside the contactor box, the system can detect whether a fire has occurred inside the box. When a fire breaks out inside the contactor box, the connection between the traction converter and the permanent magnet traction motor can be disconnected through a two-stage redundant controllable structure consisting of a controllable isolating contactor and an excitation fuse, preventing any impact on the safety of the traction converter and the permanent magnet traction motor. It is particularly important to note that the fire protection scheme provided in this embodiment is an active detection and active protection scheme. This is different from the passive fire protection scheme in the above embodiment, which uses a high-temperature resistant material for the contactor box and has fire-resistant layers applied to the inner and outer surfaces of the contactor box. These are two non-conflicting and complementary fire protection schemes. When the active fire protection scheme provided in this embodiment is implemented together with the passive fire protection scheme provided in the above embodiment, the safety hazards caused by a fire in the isolating contactor can be further avoided.

[0088] It is readily apparent that several mature technologies already exist in the field of fire detection. Fire detection can be achieved by detecting temperature, smoke concentration, specific wavelengths of light produced by flames, or specific gases produced by flames. Therefore, the specific implementation of the fire detection unit in this embodiment should be determined based on the fire detection method employed. This embodiment does not impose any limitations on this, and a suitable fire detection scheme can be freely selected according to actual needs.

[0089] However, to further illustrate this device, this application also provides an optional embodiment. For example... Figure 2 As shown, the fire detection unit includes a temperature sensing cable and a smoke detector. The temperature sensing cable is used to detect the temperature inside the contactor box. The smoke detector is used to detect the smoke concentration inside the contactor box. The control unit is also used to determine whether a fire has occurred inside the contactor box based on the temperature detected by the temperature sensing cable and the smoke concentration detected by the smoke detector.

[0090] As described above, this embodiment achieves a composite fire detection solution by using two fire detection methods based on different detection principles and approaches: a heat-sensing cable and a smoke detector. This results in more comprehensive and accurate fire detection, leading to better fire detection performance.

[0091] In summary, the redundant fault protection device for a permanent magnet traction system provided in this application achieves two-stage redundant back-EMF isolation control through an excitation fuse and an isolating contactor. Even when the isolating contactor malfunctions and cannot disconnect, isolation can still be ensured by the excitation fuse. Furthermore, the excitation fuse and isolating contactor are independent of the traction converter and permanent magnet traction motor, housed in a separate contactor box. Due to the protection of the contactor box, external environmental influences on the excitation fuse and isolating contactor can be avoided. On the other hand, if the isolating contactor arcs or even catches fire due to excessive current from the traction converter, the isolating box can effectively control the fire within a certain range, preventing it from spreading to the traction converter, permanent magnet traction motor, or even other equipment on the train, further ensuring the safety of the train traction system and the entire train. Moreover, in addition to achieving redundant back-EMF isolation, the excitation fuse, based on its fuse characteristics, can also provide overcurrent protection. This helps reduce the probability of the isolating contactor catching fire due to high current, further improving the safety of the train traction system.

[0092] In the above embodiments, a redundancy fault protection device for a permanent magnet traction system has been described in detail. This application also provides an embodiment corresponding to a redundancy fault protection method for a permanent magnet traction system. A redundancy fault protection method for a permanent magnet traction system, applied to the redundancy fault protection device for a permanent magnet traction system as provided in the above embodiments, includes:

[0093] S11: Determine if the isolating contactor is experiencing a failure to disconnect.

[0094] S12: If it occurs, obtain the three-phase current output by the inverter in the traction converter.

[0095] S13: If the three-phase current meets the fault conditions, the control excitation fuse will be disconnected.

[0096] Specifically, regarding step S11, the inability of the isolating contactor to disconnect means that the isolating contactor cannot properly disconnect the circuit. This state can be detected by software or hardware. In software mode, after the control unit issues a disconnect command to the isolating contactor, the isolating contactor should return its current state, which should be a disconnected state. If the control unit fails to receive this status feedback as expected, it can be considered that the isolating contactor has an inability to disconnect. In hardware mode, an inability to disconnect means that there is a circuit between the two ends of the isolating contactor, and an electrical signal can be transmitted from one end to the other. Therefore, the inability to disconnect can be detected by detecting the signals at both ends of the isolating contactor. This embodiment does not limit the specific inability to disconnect detection scheme used, but provides a preferred scheme. Step S11 specifically includes:

[0097] S111: Send a disconnect command to the isolating contactor.

[0098] S112: If no status information is received from the isolating contactor within the preset time, or if the received status information does not indicate that the isolating contactor is in the open state, then it is determined that the isolating contactor has a failure to disconnect.

[0099] In this embodiment, the specific duration of the preset time is not limited and can be determined according to the actual situation.

[0100] Therefore, this embodiment provides a software-based fault detection scheme for an isolating contactor that cannot be disconnected. After issuing a disconnect command to the isolating contactor, it determines whether no status information is received from the isolating contactor within a certain period, or whether the received status information does not indicate that the isolating contactor is in an open state. If either of these two situations occurs, it indicates that the isolating contactor has a fault that prevents it from disconnecting, and in this case, the isolating contactor cannot properly perform its function of isolating back EMF. The fault detection scheme provided in this embodiment is simple to implement and requires no additional hardware circuitry. Especially when the control unit reuses the original TCU, the TCU already has a control strategy for the isolating controller, making it easy to determine the response of the isolating controller.

[0101] Furthermore, regarding step S12, when it is determined that the isolating contactor has a failure to disconnect, a scheme is implemented to further determine whether it is necessary to control the excitation fuse to disconnect for protection by detecting the three-phase current status output by the traction converter. Specifically, as in step S13, this corresponds to the control logic when it is determined from the three-phase current status that it is necessary to control the excitation fuse to disconnect.

[0102] On the one hand, regarding how to determine whether the fuse needs to be tripped based on the three-phase current state, as shown in step S12 above, it is determined by whether the three-phase current meets the fault conditions. These fault conditions can be determined based on the current characteristics reflected in the three-phase output current of the traction converter when any one or more faults occur in the train traction system that require disconnecting the path between the traction converter and the permanent magnet traction motor. This embodiment does not impose any limitations on this. However, this embodiment also provides an optional implementation scheme:

[0103] As illustrated in the embodiments of the above-described device section, a major factor leading to the disconnection failure of the isolating contactor is a short circuit in the traction converter, resulting in excessive output current. Since the location of the short circuit in the traction converter is uncertain, directly detecting its presence is difficult. Therefore, the presence of this condition can be determined by detecting the magnitude of the three-phase output current of the traction converter. Based on this, the specific fault conditions described above are as follows:

[0104] If any one of the three-phase currents Iu, Iv, and Iw satisfies the condition that its effective value is greater than the corresponding threshold value I0. The specific value of the threshold value I0 is not limited in this embodiment, and the threshold values ​​I0 for different phase currents can be the same or different.

[0105] On the other hand, step S13 corresponds to the control logic when the three-phase current meets the fault conditions. That is, by turning off the excitation fuse, isolation between the traction converter and the permanent magnet traction motor is ensured, preventing further escalation of the fault. It should be noted that although turning off the excitation fuse can achieve back-EMF isolation, and the scenario corresponding to step S13 is the same as the situation determined in step S11 where the isolating contactor fails to open, the failure detection is implemented through software. In this case, the isolating contactor may open, but a problem with the status feedback could lead to the detection of a failure to open. That is, the isolating contactor's opening function may be normal, but communication or other issues could cause it to be detected as having a failure to open. In this situation, controlling the isolating contactor to open can achieve redundant protection together with the excitation fuse.

[0106] Furthermore, when a fault condition corresponding to step S13 occurs, this embodiment also provides an optional implementation scheme. The above method further includes: controlling the inverter to lock down and sending a stop inspection request to the train central control unit.

[0107] As described above, when the isolating contactor fails to disconnect and the three-phase current output by the traction converter is determined to be excessive based on the three-phase current and fault conditions, it indicates that not only the isolating contactor but also the traction converter has experienced a serious fault. Therefore, the protection control logic provided in this embodiment controls the inverter in the traction converter to block, prohibiting further output of three-phase current and reducing subsequent risks. Furthermore, a stop inspection request is sent to the train control unit, promptly reminding train maintenance personnel to stop, investigate the cause of the fault, and troubleshoot it. Especially when the control unit reuses the TCU to implement and execute this method, the TCU and the train control unit already have a usable communication connection, requiring no additional configuration.

[0108] Furthermore, when the isolating contactor fails to disconnect but the three-phase current does not meet the fault conditions, this embodiment also provides a suitable alternative solution. The above method further includes:

[0109] S14: If the three-phase current does not meet the fault conditions, the inverter is locked and a fault message indicating that the contactor cannot be disconnected is reported to the train control unit.

[0110] As described above, when the isolating contactor fails to disconnect but the three-phase current does not meet the fault conditions, although there is an anomaly in the train traction system, it is less severe than the situation corresponding to step S13. The main issue is that the isolating contactor with the disconnection failure cannot effectively isolate the back EMF generated by the permanent magnet traction motor. In this case, the traction converter is easily affected by the back EMF, leading to difficult-to-solve control problems. Therefore, this embodiment, upon determining that this situation has occurred, controls the inverter in the traction converter to be blocked, prohibiting the continued output of three-phase current and reducing subsequent risks. It also reports the contactor disconnection failure information to the train central control unit, alerting maintenance personnel to this situation. However, it should be noted that this differs from the situation requiring a stop for inspection as described in step S13. This embodiment addresses a less severe fault situation, only requiring the blocking of the output of the inverter with the faulty isolating contactor, preventing the corresponding permanent magnet traction motor from providing traction. However, this does not affect the operation of other inverters and other permanent magnet traction motors, so the train can continue to run.

[0111] On the other hand, as can be seen from the embodiments of the above-mentioned device, in addition to using the three-phase current output by the inverter as the control basis for the isolation contactor and the excitation fuse, in some embodiments, the device also includes a fire detection unit. Further, the fire detection unit may be composed of a heat-sensing cable and a smoke detector. In this case, based on the detection of whether a fire has occurred in the contactor box, this embodiment also provides a further control scheme. The above method also includes:

[0112] S20: When a fire is determined to be inside the contactor box based on the temperature detected by the temperature sensing cable or the smoke concentration detected by the smoke detector, the control isolating contactor and excitation fuse are disconnected, the control inverter is blocked, and a stop inspection request is sent to the train central control unit.

[0113] In other words, this embodiment provides a protection and control scheme for a fire occurring inside the isolator box. The temperature inside the isolator box is detected by a temperature-sensing cable installed in the box, and the smoke concentration is detected by a smoke detector installed in the box, thus comprehensively determining whether a fire has occurred inside the contactor box. When a fire is detected inside the isolator box based on either detection source, the isolating contactor and excitation fuse are promptly disconnected, the inverter is locked, and the electrical connection between the traction converter and the permanent magnet traction motor is severed to ensure the safety of the train traction system. Simultaneously, fire, as a serious abnormal situation, poses a risk of spreading to other components in the train or even the entire train. In this case, it is necessary to promptly request a stop and inspection from the train's central control unit to troubleshoot the fault and ensure the safe operation of the train.

[0114] Furthermore, when the implementation scheme provided in this embodiment is applied, combined with steps S11-S13 of the method described above, comprehensive protection based on three different dimensions—the on / off state of the isolation contactor, the current state, and the fire state—can be achieved, ensuring the safe and reliable operation of the train traction system. At this time, this embodiment also provides a control flow that integrates the above embodiments, such as... Figure 5 As shown:

[0115] First, the TCU acquires in real time the current signals collected by each current sensor in the traction converter, the closed / open status signals of the isolating contactor, and the fire signal output by the heat-sensing cable / smoke detector when a fire is detected. Then, since fire protection is the first priority, it first determines whether a fire signal indicating the presence of a fire has been received from the heat-sensing cable / smoke detector. If so, the inverter is blocked, the isolating contactor and the excitation fuse are disconnected, and a train stop inspection is requested. If not, it further determines whether the isolating contactor has a failure to disconnect. If no failure to disconnect occurs, the train is in normal condition and continues to run. If a failure to disconnect occurs, it further determines whether the three-phase current meets the fault condition (i.e., any phase current is greater than the threshold value I0). If it does, the fault is relatively serious, requiring the inverter to be blocked, the isolating contactor and the excitation fuse to disconnect, and a train stop inspection to be requested. If the condition is not met, it indicates that only the isolating contactor has a failure to disconnect, the corresponding inverter is blocked, the other inverters and permanent magnet traction motors operate normally, and the train continues to run.

[0116] The above embodiments have described in detail a method for redundancy fault protection of a permanent magnet traction system. This application also provides an embodiment of a corresponding redundancy fault protection system for a permanent magnet traction system. It should be noted that this application describes the system-related embodiments from two perspectives: one based on functional modules and the other based on hardware.

[0117] From the perspective of functional modules, this embodiment provides a redundancy fault protection system for a permanent magnet traction system, including:

[0118] The detection module is used to determine whether the isolating contactor has a failure to disconnect.

[0119] The acquisition module is used to acquire the three-phase current output by the inverter in the traction converter if the condition is met.

[0120] The protection module is used to control the excitation fuse to open if the three-phase current meets the fault conditions.

[0121] Since the embodiments of the system part correspond to the embodiments of the method part, please refer to the description of the embodiments of the method part for the embodiments of the system part, and they will not be repeated here.

[0122] Another embodiment of this application provides a redundancy fault protection system for a permanent magnet traction system, including: a memory for storing computer programs;

[0123] A processor is used to execute a computer program to implement the steps of a redundancy fault protection method for a permanent magnet traction system as described in the above embodiments.

[0124] The redundant fault protection system for a permanent magnet traction system provided in this embodiment may include, but is not limited to, TCU, MCU, CPU, etc.

[0125] The processor may include one or more processing cores, such as a quad-core processor or an octa-core processor. The processor can be implemented using at least one of the following hardware forms: Digital Signal Processor (DSP), Field-Programmable Gate Array (FPGA), or Programmable Logic Array (PLA). The processor may also include a main processor and coprocessors. The main processor, also known as the Central Processing Unit (CPU), is used to process data in the wake-up state; the coprocessors are low-power processors used to process data in the standby state. In some embodiments, the processor may integrate a Graphics Processing Unit (GPU), which is responsible for rendering and drawing the content to be displayed on the screen. In some embodiments, the processor may also include an Artificial Intelligence (AI) processor, which handles computational operations related to machine learning.

[0126] The memory may include one or more computer-readable storage media, which may be non-transitory. The memory may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices or flash memory devices. In this embodiment, the memory is used to store at least the following computer program, which, after being loaded and executed by a processor, is capable of implementing the relevant steps of a permanent magnet traction system redundancy fault protection method disclosed in any of the foregoing embodiments. In addition, the resources stored in the memory may also include an operating system and data, and the storage method may be temporary or permanent storage. The operating system may include Windows, Unix, Linux, etc. The data may include, but is not limited to, a permanent magnet traction system redundancy fault protection method.

[0127] In some embodiments, a permanent magnet traction system redundancy fault protection system may further include a display screen, input / output interfaces, communication interfaces, a power supply, and a communication bus.

[0128] Those skilled in the art will understand that the above-described structure does not constitute a limitation on a permanent magnet traction system redundancy fault protection system, and may include more or fewer components than described above.

[0129] This application provides a redundancy fault protection system for a permanent magnet traction system, including a memory and a processor. When the processor executes a program stored in the memory, it can implement the following method: a redundancy fault protection method for a permanent magnet traction system.

[0130] Finally, this application also provides an embodiment corresponding to a computer-readable storage medium. The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps described in the above method embodiments.

[0131] It is understood that if the methods in the above embodiments are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and executes all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0132] The foregoing provides a detailed description of a redundancy fault protection device, method, system, and medium for a permanent magnet traction system. The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to in the method section. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of this application.

[0133] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A redundant fault protection device for a permanent magnet traction system, characterized in that, The device comprises: an isolation contactor, an excitation fuse, a contactor box, a current detection unit and a control unit; the isolation contactor and the excitation fuse are arranged in the contactor box, and are connected in series between a traction converter and a permanent magnet traction motor; the current detection unit is connected with three-phase output terminals of an inverter in the traction converter, and is used for detecting three-phase currents; the control unit is connected with the current detection unit, the isolation contactor and the excitation fuse, and is used for controlling on-off of the isolation contactor and the excitation fuse according to the three-phase currents.

2. The permanent magnet traction system redundant fault protection device of claim 1, wherein, Further comprising: a fire detection unit; the fire detection unit is arranged in the contactor box, and is connected with the control unit, and is used for detecting whether a fire occurs in the contactor box; the control unit is further used for controlling the isolation contactor and the excitation fuse to be turned off when the fire detection unit detects that a fire occurs in the contactor box.

3. The permanent magnet traction system redundant fault protection device of claim 2, wherein, the fire detection unit comprises a temperature sensing cable and a smoke detector; the temperature sensing cable is used for detecting a temperature in the contactor box; the smoke detector is used for detecting a smoke concentration in the contactor box; the control unit is further used for determining whether a fire occurs in the contactor box according to the temperature detected by the temperature sensing cable and the smoke concentration detected by the smoke detector.

4. The permanent magnet traction system redundant fault protection device of claim 1, wherein, the current detection unit is an output current sensor in the traction converter, and the control unit is a traction control unit in the traction converter; the traction control unit is connected with the isolation contactor and the excitation fuse arranged in the contactor box through a hard wire.

5. The permanent magnet traction system redundant fault protection device of claim 1, wherein, inner and outer surfaces of the contactor box are provided with a fireproof layer.

6. The redundant fault protection device for a permanent magnet traction system of any one of claims 1 to 5, characterized in that the contactor box is arranged close to the permanent magnet traction motor.

7. The permanent magnet traction system redundant fault protection device of claim 6, wherein, the number of the permanent magnet traction motors is multiple; the number of the contactor boxes is multiple, and corresponds to the permanent magnet traction motors one by one; each contactor box is arranged close to a bogie where the corresponding permanent magnet traction motor is arranged.

8. A method of permanent magnet traction system redundant fault protection, characterized by, applied to the permanent magnet traction system redundancy fault protection device in claim 1; the method comprises: determining whether a breakage failure occurs in the isolation contactor; if the breakage failure occurs, obtaining three-phase currents output by an inverter in a traction converter; if the three-phase currents meet a fault condition, controlling an excitation fuse to be turned off.

9. The permanent magnet traction system redundant fault protection method of claim 8, wherein, the determination of whether the breakage failure occurs in the isolation contactor comprises: sending an off instruction to the isolation contactor; if state information fed back by the isolation contactor is not received within a preset time, or the state information does not represent that the isolation contactor is in an off state, it is determined that the breakage failure occurs in the isolation contactor.

10. The permanent magnet traction system redundant fault protection method of claim 8, wherein, when the three-phase currents meet the fault condition, further comprising: controlling the inverter to be locked, and sending a stop inspection application to a train control unit.

11. The permanent magnet traction system redundant fault protection method of claim 10, wherein, after the three-phase currents output by the inverter in the traction converter are obtained, further comprising: if the three-phase currents do not meet the fault condition, controlling the inverter to be locked, and reporting a contactor breakage failure information to the train control unit.

12. The redundant fault protection method for a permanent magnet traction system according to any one of claims 8 to 11, characterized in that, The permanent magnet traction system redundancy fault protection device further comprises a temperature sensing cable and a smoke detector; the temperature sensing cable is used to detect the temperature in the contactor box; the smoke detector is used to detect the smoke concentration in the contactor box; The method further comprises: When it is determined that a fire occurs in the contactor box according to the temperature detected by the temperature sensing cable or the smoke concentration detected by the smoke detector, the isolation contactor and the energizing fuse are controlled to be opened, the inverter is blocked, and a stop inspection application is sent to a train control unit.

13. A permanent magnet traction system redundant fault protection system, characterized by, The permanent magnet traction system redundancy fault protection device according to claim 1; The system comprises: A detection module is configured to determine whether the isolation contactor has a failure of not being able to be opened; An acquisition module is configured to acquire three-phase currents output by inverters in the traction converter if the failure occurs; A protection module is configured to control the energizing fuse to be opened if the three-phase currents satisfy a fault condition.

14. A permanent magnet traction system redundant fault protection system, characterized by, It comprises: A memory is configured to store a computer program; A processor is configured to implement the steps of the permanent magnet traction system redundancy fault protection method according to any one of claims 8 to 12 when executing the computer program.

15. A computer-readable storage medium, characterized in that, A computer program is stored on the computer readable storage medium, and the computer program is executed by the processor to implement the steps of the permanent magnet traction system redundancy fault protection method according to any one of claims 8 to 12.

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