Electrically-driven locked-rotor protection system, method and device, electronic equipment and storage medium

Abstract

The embodiment of the invention provides an electric drive locked-rotor protection system, method and device, electronic equipment and a storage medium, and relates to the technical field of electric drive control. The system comprises at least two paths of phase current sensors which are used for carrying out current sampling in a locked-rotor working condition or when a stator temperature sensor fails, so as to limit the maximum phase current of each phase within the maximum continuous locked-rotor phase current; and the at least one stator temperature sensor is used for measuring the temperature of the stator, and synchronously using the slope starting locked-rotor power limiting strategy and the stator temperature sampling over-temperature power limiting strategy in the locked-rotor working condition and when the at least one stator temperature sensor is normal, so as to assist the motor stator to perform temperature protection. The maximum continuous locked-rotor phase current protection strategy and the phase current sampling auxiliary stator temperature protection strategy are adopted, the electric driving capacity is exerted as far as possible, the thermal runaway and demagnetization risks easily occurring in the locked-rotor working condition are avoided, the robustness is enhanced, and the problems that an existing protection method is poor in robustness and needs shutdown protection are solved.

Description

Technical Field

[0001] The present application relates to the field of electric drive control technology, and more specifically, to an electric drive stall protection system, method, device, electronic device and storage medium. Background Art

[0002] When the three-phase electric drive is working normally, the three-phase current is a sinusoidal wave that changes alternately, so the internal heat of the electric drive is uniform. The motor stator temperature sensor is an NTC resistor placed in the motor stator coil, usually with one or two circuits. When the electric drive is in a stalled rotor condition (including a ramp-starting stalled rotor condition and a static AHF active heating condition), the current may be concentrated in a single-phase circuit that is not monitored by a temperature sensor, resulting in internal heat accumulation and a risk of demagnetization. In order to protect the stalled rotor condition, the system can only be derated in advance, sacrificing some performance, and the robustness is poor; when the stator temperature sensor fails, the system can only be shut down for protection, otherwise there is a risk of thermal runaway. Summary of the invention

[0003] The purpose of the embodiments of the present application is to provide an electric drive stall protection system, method, device, electronic device and storage medium. Under a stall condition, the maximum continuous stall phase current protection is adopted. When the rotor is stalled and at least one stator temperature sensor is normal, the phase current sampling is adopted to assist the stator temperature protection strategy, so as to maximize the electric drive capability, avoid the risks of thermal runaway and demagnetization that are prone to occur in the stall condition, enhance robustness, and solve the problem that the existing protection method has poor robustness and requires shutdown protection.

[0004] The embodiment of the present application provides an electric drive stall protection system, the system comprising a permanent magnet synchronous motor, and further comprising:

[0005] Phase current sensors, at least two of which are respectively arranged at any two phases of the U phase, V phase and W phase of the permanent magnet synchronous motor, for current sampling in a stalled rotor condition or when the stator temperature sensor fails, so as to limit the maximum phase current of each phase to within the maximum continuous stalled rotor phase current, and assist the motor stator in temperature protection;

[0006] At least one stator temperature sensor is arranged on one side of the U-phase coil, the V-phase coil or the W-phase coil to measure the stator temperature. In the stall condition and when at least one stator temperature sensor is normal, the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy are used simultaneously to assist the motor stator in temperature protection.

[0007] In the above implementation process, the maximum phase current of each phase is limited to the maximum continuous stall phase current to avoid the risk of thermal runaway or demagnetization due to further temperature increase. In order to maximize the electric drive capability and avoid thermal runaway problems, the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy can also be used simultaneously to enhance robustness, thus solving the problem that the existing protection methods have poor robustness and require shutdown protection.

[0008] Furthermore, the torque is limited by taking the minimum value of the power coefficient in the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy.

[0009] In the above implementation process, power limiting protection is performed by limiting the torque by using the minimum value of the power coefficient in the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy. This can fully utilize the maximum capacity of the electric drive itself and limit the risks of thermal runaway and demagnetization that are prone to occur in stall conditions.

[0010] The present application also provides an electric drive stall protection method, which is applied to an electric drive stall protection system. The method includes:

[0011] In the case of a stall condition or stator temperature sensor failure, the phase current sensor is used to sample the current and limit the maximum phase current of each phase to within the maximum continuous stall phase current to assist the motor stator in temperature protection.

[0012] In a stalled rotor condition and when at least one stator temperature sensor is normal, the ramp-up stalled rotor power limiting strategy and the stator temperature sampling over-temperature power limiting strategy are used simultaneously to assist the motor stator in temperature protection.

[0013] In the above implementation process, the maximum phase current of each phase is limited to the maximum continuous stall phase current to avoid the risk of thermal runaway or demagnetization due to further temperature increase. In order to maximize the electric drive capability and avoid thermal runaway problems, the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy can also be used simultaneously to enhance robustness, thus solving the problem that the existing protection methods have poor robustness and require shutdown protection.

[0014] Furthermore, limiting the maximum phase current of each phase to within the maximum continuous locked-rotor phase current includes:

[0015] Under the locked-rotor condition, the maximum phase current when the stator temperature reaches dynamic equilibrium is 285A, and the absolute value of the maximum continuous locked-rotor phase current is 285A, limiting the maximum phase current of each phase to within 285A.

[0016] In the above implementation process, the maximum phase current of each phase is limited to within 285A, and the temperature sensor-free stall protection is realized.

[0017] Furthermore, the slope starting stall power limiting strategy includes:

[0018] If the stator temperature sensor is set in the U phase, the ratio of the U phase current to the maximum phase current obtained by three-phase sampling is between 0 and 0.25, and the limiting power factor is set to 25%;

[0019] If the ratio of the U phase current to the maximum phase current is between 0.25 and 0.5, the limiting power factor is set to 50%;

[0020] If the ratio of the U phase current to the maximum phase current is between 0.5 and 0.75, the limiting power factor is set at 75%;

[0021] If the ratio of the U phase current to the maximum phase current is between 0.75 and 1, the limiting power factor is set to 100%.

[0022] In the above implementation process, the power limiting coefficient can be determined according to the ratio of the U-phase current to the maximum phase current.

[0023] Furthermore, the synchronous use of the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy includes:

[0024] The torque is limited by taking the minimum value of the power coefficient in the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy.

[0025] In the above implementation process, the power coefficients of the two strategies take small values, which can enable the electric drive to exert its maximum capacity without overheating.

[0026] The present application also provides an electric drive stall protection device, the device comprising:

[0027] The current limiting module is used to use the phase current sensor to perform current sampling in the case of a stall condition or stator temperature sensor failure, and to limit the maximum phase current of each phase to within the maximum continuous stall phase current to assist the motor stator in temperature protection.

[0028] The power limiting module is used to synchronously use the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy in a stalled rotor condition and when at least one stator temperature sensor is normal, so as to assist the motor stator in temperature protection.

[0029] In the above implementation process, the maximum phase current of each phase is limited to the maximum continuous stall phase current to avoid the risk of thermal runaway or demagnetization due to further temperature increase. In order to maximize the electric drive capability and avoid thermal runaway problems, the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy can also be used simultaneously to enhance robustness, thus solving the problem that the existing protection methods have poor robustness and require shutdown protection.

[0030] Furthermore, the power limiting module includes:

[0031] The power coefficient minimization module is used to take the minimum value of the power coefficient in the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy to limit the torque.

[0032] In the above implementation process, the power coefficients of the two strategies take small values, which can enable the electric drive to exert its maximum capacity without overheating.

[0033] An embodiment of the present application further provides an electronic device, which includes a memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to execute the above-mentioned electric drive stall protection method.

[0034] An embodiment of the present application further provides a readable storage medium, wherein the readable storage medium stores computer program instructions, and when the computer program instructions are read and executed by a processor, the above-mentioned electric drive stall protection method is executed. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 A flow chart of an electric drive stall protection method provided in an embodiment of the present application;

[0037] Figure 2 A maximum continuous stall phase current protection flow chart provided in an embodiment of the present application;

[0038] Figure 3 A flow chart of the phase current sampling assisted stator temperature protection strategy provided in an embodiment of the present application;

[0039] Figure 4 A structural block diagram of an electric drive stall protection device provided in an embodiment of the present application;

[0040] Figure 5 A structural block diagram of another electric drive stall protection device provided in an embodiment of the present application.

[0041] icon:

[0042] 100-current limiting module; 200-power limiting module; 201-power factor small module. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0044] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0045] Please see Figure 1 , Figure 1 An electric drive stall protection system provided in an embodiment of the present application includes a permanent magnet synchronous motor and further includes:

[0046] Phase current sensors, at least two of which are respectively arranged at any two phases of the U phase, V phase and W phase of the permanent magnet synchronous motor, for current sampling in a stalled rotor condition or when the stator temperature sensor fails, so as to limit the maximum phase current of each phase to within the maximum continuous stalled rotor phase current, and assist the motor stator in temperature protection;

[0047] At least one stator temperature sensor is arranged on one side of the U-phase coil, the V-phase coil or the W-phase coil to measure the stator temperature. In the stall condition and when at least one stator temperature sensor is normal, the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy are used simultaneously to assist the motor stator in temperature protection.

[0048] Among them, the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy are used simultaneously. Specifically, the torque can be limited by taking the minimum value of the power coefficient in the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy.

[0049] As for the number of sensors, due to the characteristics of the three-phase motor circuit, when there are only two phase current sensors, the third phase can be estimated based on the sum of the three-phase currents being 0. Therefore, there can be two or three phase current sensors. In the case of a stall condition or a stator temperature sensor failure, the sampling parameters of the three-phase current sensor can be used to provide auxiliary temperature protection for the motor.

[0050] The premise of this solution is that the phase current sensor is in normal working condition. The fault detection of temperature sensor and phase current sensor is generally judged by detecting whether the sampling value is within the normal range. It belongs to the prior art and is not described in detail in this application.

[0051] The main sources of heat loss in permanent magnet synchronous motors are mechanical loss, core loss and stator winding loss. The heat loss of controller power devices mainly includes conduction loss and switching loss. Except for mechanical loss, the other losses are positively correlated with current. When the motor is in a stalled rotor condition (including ramp-starting stall and static active heating conditions), the current in the three-phase circuit is approximately direct current. Since it is relatively complicated to directly calculate the loss, the maximum current that a single-phase circuit can withstand can be investigated based on the maximum ambient temperature, maximum water temperature, and maximum cooling flow rate of the vehicle design. Under this condition, the maximum phase current when the stator temperature reaches dynamic equilibrium is the maximum phase current for continuous stalling.

[0052] The present application also provides an electric drive stall protection method, which is applied to the above-mentioned electric drive stall protection system. Figure 1 FIG. 1 is a flow chart of an electric drive stall protection method, which specifically includes the following steps:

[0053] Step S100: When the motor is in a locked-rotor condition or the stator temperature sensor fails, the phase current sensor is used to perform current sampling, and the maximum phase current of each phase is limited to within the maximum continuous locked-rotor phase current to assist the motor stator in temperature protection;

[0054] Step S200: In a stalled rotor condition and when at least one stator temperature sensor is normal, the ramp-starting stalled rotor power limiting strategy and the stator temperature sampling over-temperature power limiting strategy are used simultaneously to assist the motor stator in temperature protection.

[0055] As one of the embodiments, under the locked-rotor condition, the maximum phase current when the stator temperature reaches dynamic equilibrium is 285A, and the absolute value of the maximum continuous locked-rotor phase current is 285A, and the maximum phase current of each phase is limited to within 285A.

[0056] As shown in Table 1, the phase current and three-phase stator temperature data of a permanent magnet synchronous motor at different stall angles under stalled static active heating conditions are shown.

[0057]

[0058]

[0059] Table 1 Stator temperature at different angles of locked-rotor heating

[0060] The electric drive has two stator temperature sensors, one close to the U phase and the other close to the V phase. The stator temperature fed back by the software is the maximum value of the two stator temperature sensors. When the stall angle is 60° or 240°, the W phase current reaches its maximum value and the W phase stator temperature reaches 155 degrees. At this time, the software monitoring of the two stator temperature sensors is only 93 degrees, and the temperature difference reaches 62 degrees. If the temperature rises further, the electric drive is at risk of thermal runaway or demagnetization. Under the same cooling conditions, the data shows that the current and temperature are positively correlated. The stator derating protection temperature of the motor is tentatively set to 155 degrees. Therefore, the protection strategy can be set as the absolute value of the phase current cannot be greater than 285A (the cooling flow request needs to be in accordance with the maximum flow request). 285A is the maximum continuous stall phase current. Figure 2 The figure shows the maximum continuous stall phase current protection flow chart.

[0061] The power limiting strategy for stalling at hill start includes:

[0062] If the stator temperature sensor is set in the U phase, the ratio of the U phase current to the maximum phase current obtained by three-phase sampling is between 0 and 0.25, and the limiting power factor is set to 25%;

[0063] If the ratio of the U phase current to the maximum phase current is between 0.25 and 0.5, the limiting power factor is set to 50%;

[0064] If the ratio of the U phase current to the maximum phase current is between 0.5 and 0.75, the limiting power factor is set at 75%;

[0065] If the ratio of the U phase current to the maximum phase current is between 0.75 and 1, the limiting power factor is set to 100%.

[0066] The ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy are used simultaneously, including:

[0067] The torque is limited by taking the minimum value of the power coefficient in the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy.

[0068] For example, in order to maximize the electric drive capability and avoid thermal runaway problems, in addition to finding out the maximum continuous stall phase current, the ratio of the stator temperature sensor and its corresponding phase current sampling value to the maximum phase current sampled by the three-way phase current sensor can also be used for judgment. For example, a permanent magnet synchronous electric drive stator has a temperature sensor located close to the U phase coil. The maximum phase current sampled by the three-way phase current sensor is set as Imax, and the ramp-start stall power limiting strategy is set as follows: when the U phase current / Imax is between 0 and 0.25, the power factor is set to 25%, when it is between 0.25 and 0.5, it is set to 50%, when it is between 0.5 and 0.75, it is set to 75%, and when it is between 0.75 and 1, it is set to 100% (the specific range and power limiting factor vary according to different electric drives, and need to be tested through bench stall test. For the power limiting factor, no limitation is made here). The ramp-start stall power limiting strategy needs to be used simultaneously with the stator temperature sampling over-temperature power limiting strategy (power limiting is performed when the stator temperature reaches the threshold, and no limitation is made on the specific power limiting coefficient). The power coefficients of the two take the smaller value, such as Figure 3 The figure shows the flow chart of the phase current sampling assisted stator temperature protection strategy. When the stator temperature sensor fails, the maximum continuous stall current is used for protection to ensure that the vehicle will not experience stator demagnetization and thermal runaway.

[0069] In specific applications, if the electric drive is in a stalled condition and at least one motor stator temperature sensor is normal, the ramp-starting stalled-rotor power limiting strategy and the stator temperature sampling over-temperature power limiting strategy can be used simultaneously to enable the electric drive to achieve maximum capacity without overheating.

[0070] The stator locked rotor phase current protection strategy can accurately identify the distribution of the locked rotor current under the locked rotor condition, and perform power limiting protection according to the test results pre-tested on the bench test. The stator temperature sampling over-temperature power limiting strategy can ignore the temperature protection of the locked rotor condition and perform protection according to the uniform heating of the motor stator. The power coefficient of the two strategies takes the smaller value. In this way, the maximum capacity of the electric drive itself can be fully utilized, and the risk of thermal runaway and demagnetization that is prone to occur in the locked rotor condition can be limited.

[0071] In another application scenario, when all motor stator temperature sensors fail, the maximum phase current of each phase can be limited to the maximum continuous stall phase current, thereby reducing the fault level.

[0072] If the cooling system is working normally at this time, and the stator heat loss is uniform when the motor is running in non-locked rotor conditions, the vehicle can be allowed to run at reduced power and the instrument alarm can be issued. If the stator temperature sensor fails and the heat is severe in the locked rotor condition, the current motor temperature status cannot be determined. Generally, it is necessary to shut down the motor for protection and tow the vehicle to an after-sales point for repair. This method can be used to limit the phase current to no more than the maximum continuous locked rotor phase current when the motor is in a locked rotor condition, and realize locked rotor protection without a temperature sensor, so that customers can safely go to the after-sales point for repairs by themselves.

[0073] The present application also provides an electric drive stall protection device, which is applied to the above-mentioned electric drive stall protection method, such as Figure 4 The figure is a structural block diagram of an electric drive stall protection device, which includes but is not limited to:

[0074] The current limiting module 100 is used to use the phase current sensor to perform current sampling in a stalled rotor condition or when the stator temperature sensor fails, and to limit the maximum phase current of each phase to within the maximum continuous stalled rotor phase current to assist the motor stator in temperature protection.

[0075] The power limiting module 200 is used to synchronously use the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy in a stalled rotor condition and when at least one stator temperature sensor is normal, so as to assist the motor stator in temperature protection.

[0076] like Figure 5 FIG. 2 is a structural block diagram of another electric drive stall protection device, wherein the power limiting module 200 includes:

[0077] The power coefficient minimization module 201 is used to obtain the minimum value of the power coefficient in the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy to limit the torque.

[0078] The specific implementation process has been specifically described in the method embodiment and will not be repeated here.

[0079] An embodiment of the present application further provides an electronic device, which includes a memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to execute the above-mentioned electric drive stall protection method.

[0080] An embodiment of the present application further provides a readable storage medium, wherein the readable storage medium stores computer program instructions, and when the computer program instructions are read and executed by a processor, the above-mentioned electric drive stall protection method is executed.

[0081] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0082] In addition, the functional modules in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0083] If the functions are implemented in the form of software function modules 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 the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0084] The above description is only an embodiment of the present application and is not intended to limit the scope of protection of the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0085] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0086] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

Claims

1. An electric drive stall protection system, characterized in that: The system includes a permanent magnet synchronous motor, and further includes: Phase current sensors, at least two of which are respectively arranged at any two phases of the U phase, V phase and W phase of the permanent magnet synchronous motor, for current sampling in a stalled rotor condition or when the stator temperature sensor fails, so as to limit the maximum phase current of each phase to within the maximum continuous stalled rotor phase current, and assist the motor stator in temperature protection; At least one stator temperature sensor is arranged on one side of the U-phase coil, the V-phase coil or the W-phase coil to measure the stator temperature. In the stall condition and when at least one stator temperature sensor is normal, the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy are used simultaneously to assist the motor stator in temperature protection.

2. The electric drive stall protection system according to claim 1, characterized in that: The torque is limited by taking the minimum value of the power coefficient in the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy.

3. An electric drive stall protection method, characterized in that: Applied to the electric drive stall protection system according to any one of claims 1-2, the method comprising: In the case of a stall condition or stator temperature sensor failure, the phase current sensor is used to sample the current and limit the maximum phase current of each phase to within the maximum continuous stall phase current to assist the motor stator in temperature protection. In a stalled rotor condition and when at least one stator temperature sensor is normal, the ramp-up stalled rotor power limiting strategy and the stator temperature sampling over-temperature power limiting strategy are used simultaneously to assist the motor stator in temperature protection.

4. The electric drive stall protection method according to claim 3, characterized in that: The limiting of the maximum phase current of each phase to within the maximum continuous stall phase current includes: Under the locked-rotor condition, the maximum phase current when the stator temperature reaches dynamic equilibrium is 285A, and the absolute value of the maximum continuous locked-rotor phase current is 285A, limiting the maximum phase current of each phase to within 285A.

5. The electric drive stall protection method according to claim 3, characterized in that: The ramp-start stall power limiting strategy includes: If the stator temperature sensor is set in the U phase, the ratio of the U phase current to the maximum phase current obtained by three-phase sampling is between 0 and 0.25, and the limiting power factor is set to 25%; If the ratio of the U phase current to the maximum phase current is between 0.25 and 0.5, the limiting power factor is set to 50%; If the ratio of the U phase current to the maximum phase current is between 0.5 and 0.75, the limiting power factor is set at 75%; If the ratio of the U phase current to the maximum phase current is between 0.75 and 1, the limiting power factor is set to 100%.

6. The electric drive stall protection method according to claim 3, characterized in that: The synchronous use of the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy includes: The torque is limited by taking the minimum value of the power coefficient in the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy.

7. An electric drive stall protection device, characterized in that: The device comprises: The current limiting module is used to use the phase current sensor to perform current sampling in the case of a stall condition or stator temperature sensor failure, and to limit the maximum phase current of each phase to within the maximum continuous stall phase current to assist the motor stator in temperature protection; The power limiting module is used to synchronously use the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy in a stalled rotor condition and when at least one stator temperature sensor is normal, so as to assist the motor stator in temperature protection.

8. The electric drive stall protection device according to claim 7, characterized in that: The power limiting module comprises: The power coefficient minimization module is used to take the minimum value of the power coefficient in the ramp-start stall power limiting strategy and the stator temperature sampling over-temperature power limiting strategy to limit the torque.

9. An electronic device, characterized in that: The electronic device comprises a memory and a processor, the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to execute the electric drive stall protection method according to any one of claims 3 to 6.

10. A readable storage medium, characterized in that: The readable storage medium stores computer program instructions, and when the computer program instructions are read and executed by a processor, the electric drive stall protection method according to any one of claims 3 to 6 is executed.

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