Demagnetization detection method and device for permanent magnet motors

Abstract

This application relates to the field of permanent magnet motor technology, and provides a method and apparatus for detecting demagnetization of a permanent magnet motor. The method includes: controlling the motor winding inductance of the permanent magnet motor to perform energy interaction; acquiring the excitation current component of the permanent magnet motor during energy interaction; acquiring the local d-axis inductance of the permanent magnet motor during energy interaction based on the excitation current component, its current amplitude, and the d-axis drive voltage of the permanent magnet motor; determining the state of the permanent magnet motor based on the d-axis inductance; wherein the current amplitude is determined based on the excitation current component and its current offset; the state includes a demagnetized state or a non-demagnetized state. The demagnetization detection method for permanent magnet motors provided in this application can realize the demagnetization detection of permanent magnet motors using existing hardware in the electronic control system, without the need for additional hardware, thus making the demagnetization detection of permanent magnet motors more convenient.

Description

Technical Field

[0001] This application relates to the field of permanent magnet motor technology, specifically to a method and apparatus for detecting demagnetization of a permanent magnet motor. Background Technology

[0002] The operating conditions of permanent magnet motors used in electric vehicles are typically characterized by high electromagnetic load, large demagnetizing magnetic field, high motor temperature, and harsh environment. These factors can easily lead to irreversible demagnetization of the permanent magnets in the rotor of the permanent magnet motor, resulting in a decrease in motor torque performance and efficiency. Therefore, to ensure the safe and reliable operation of permanent magnet motors, it is necessary to detect demagnetization faults.

[0003] In related technologies, demagnetization detection of permanent magnet motors involves using an additional voltage sampling circuit to detect the back electromotive force (EMF). The flux linkage amplitude is then calculated using the back EMF parameters and compared with a flux linkage threshold to determine whether the permanent magnet motor has a demagnetization fault. However, this detection method requires the addition of a voltage sampling circuit for back EMF detection, resulting in high costs and increased operational complexity for permanent magnet motor demagnetization detection. Summary of the Invention

[0004] This application aims to address at least one of the technical problems existing in the related art. To this end, this application proposes a demagnetization detection method for permanent magnet motors, which can realize the demagnetization detection of permanent magnet motors through the existing hardware of the electronic control system, without the need to add additional hardware, and makes the demagnetization detection of permanent magnet motors more convenient.

[0005] This application also proposes a demagnetization detection device for permanent magnet motors.

[0006] This application also proposes an electronic device.

[0007] This application also proposes a computer-readable storage medium.

[0008] This application also proposes a vehicle.

[0009] The demagnetization detection method for a permanent magnet motor according to the first aspect of this application includes:

[0010] The inductance of the motor winding of the permanent magnet motor is controlled to perform energy interaction, and the excitation current component of the permanent magnet motor is obtained when the inductance of the motor winding is performing energy interaction.

[0011] Based on the excitation current component, the current amplitude of the excitation current component, and the d-axis drive voltage of the permanent magnet motor, the local d-axis inductance of the permanent magnet motor during energy interaction in the motor winding inductance is obtained.

[0012] The state of the permanent magnet motor is determined based on the d-axis inductance.

[0013] The current amplitude is determined based on the excitation current component and the current offset of the excitation current component.

[0014] The state includes either a demagnetized state or a non-demagnetized state.

[0015] By controlling the inductance of the permanent magnet motor windings to exchange energy, high-frequency alternating current is generated on the DC bus. The excitation current component of the permanent magnet motor during this energy exchange is acquired. Based on this excitation current component, its amplitude, and the d-axis drive voltage of the permanent magnet motor, the local d-axis inductance is monitored. The change in d-axis inductance is then used to detect demagnetization of the permanent magnet motor. Since the d-axis inductance increases when the permanent magnets are in a demagnetized state, the change in d-axis inductance can effectively detect whether demagnetization has occurred. This allows for demagnetization detection of the permanent magnet motor using existing hardware within the electronic control system, eliminating the need for additional hardware and making demagnetization detection more convenient.

[0016] According to one embodiment of this application, it also includes:

[0017] When controlling the inductance of the motor windings of the permanent magnet motor to exchange energy, the permanent magnet motor is kept in a stationary state.

[0018] According to one embodiment of this application, controlling the permanent magnet motor to be in a stationary state includes:

[0019] The torque current component of the permanent magnet motor is controlled to be zero when the motor winding inductance interacts with energy, so that the permanent magnet motor is in a stationary state.

[0020] According to one embodiment of this application, the local d-axis inductance of the permanent magnet motor during energy interaction in the motor winding inductance is obtained based on the excitation current component, the current amplitude of the excitation current component, and the d-axis drive voltage of the permanent magnet motor, including:

[0021] According to U d (t)=i d (t)R m +(2πfL d )I d，ac cos(2πft), obtain the local d-axis inductance L of the permanent magnet motor when the motor winding inductance performs energy interaction. d ;

[0022] Among them, i d R represents the excitation current component. m L represents the internal resistance of the permanent magnet motor. dI represents the d-axis inductance. d，ac The amplitude of the current is represented by t, and t represents a certain moment.

[0023] According to one embodiment of this application, the excitation current component is the d-axis excitation current component of the rotor permanent magnet of the permanent magnet motor when the rotor permanent magnet is saturated.

[0024] According to one embodiment of this application, determining the state of the permanent magnet motor based on the d-axis inductance includes:

[0025] The d-axis inductance is compared with a preset inductance threshold to determine whether the d-axis inductance is greater than the preset inductance threshold.

[0026] If so, determine that the permanent magnet motor is in a demagnetized state;

[0027] Otherwise, the permanent magnet motor is determined to be in an undemagnetized state.

[0028] According to one embodiment of this application, the preset inductance threshold is the inductance of the d-axis when the rotor permanent magnet of the permanent magnet motor is saturated.

[0029] A demagnetization detection device for a permanent magnet motor according to a second aspect embodiment of this application includes:

[0030] The motor control module is used to control the energy interaction of the motor winding inductance of the permanent magnet motor and to obtain the excitation current component of the permanent magnet motor when the energy interaction occurs in the motor winding inductance.

[0031] The inductance acquisition module is used to acquire the local d-axis inductance of the permanent magnet motor when the motor winding inductance interacts with energy, based on the excitation current component, the current amplitude of the excitation current component, and the d-axis drive voltage of the permanent magnet motor.

[0032] A demagnetization detection module is used to determine the state of the permanent magnet motor based on the d-axis inductance.

[0033] The states include either a demagnetized state or a non-demagnetized state.

[0034] An electronic device according to a third aspect of this application includes a processor and a memory storing a computer program, wherein the processor executes the computer program to implement the demagnetization detection method for a permanent magnet motor as described in any of the above embodiments.

[0035] A computer-readable storage medium according to a fourth aspect of this application stores a computer program thereon, which, when executed by a processor, implements the demagnetization detection method for a permanent magnet motor as described in any of the above embodiments.

[0036] The vehicle according to the fifth aspect of this application includes the electronic equipment described in the above embodiments.

[0037] The above-described one or more technical solutions in the embodiments of this application have at least one of the following technical effects:

[0038] By controlling the inductance of the permanent magnet motor windings to exchange energy, high-frequency alternating current is generated on the DC bus. The excitation current component of the permanent magnet motor during this energy exchange is acquired. Based on this excitation current component, its amplitude, and the d-axis drive voltage of the permanent magnet motor, the local d-axis inductance is monitored. The change in d-axis inductance is then used to detect demagnetization of the permanent magnet motor. Since the d-axis inductance increases when the permanent magnets are in a demagnetized state, the change in d-axis inductance can effectively detect whether demagnetization has occurred. This allows for demagnetization detection of the permanent magnet motor using existing hardware within the electronic control system, eliminating the need for additional hardware and making demagnetization detection more convenient. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a flowchart illustrating the demagnetization detection method for a permanent magnet motor provided in an embodiment of this application;

[0041] Figure 2 This is a schematic diagram illustrating the principle of demagnetization fault detection provided in the embodiments of this application;

[0042] Figure 3 This is a schematic diagram of the excitation current components provided in the embodiments of this application;

[0043] Figure 4 This is a schematic diagram illustrating the effect of the degree of demagnetization of the permanent magnet on the d-axis inductance provided in the embodiments of this application;

[0044] Figure 5 This is a schematic diagram of the demagnetization detection device for a permanent magnet motor provided in an embodiment of this application;

[0045] Figure 6 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0047] The demagnetization detection method and apparatus for permanent magnet motors provided in this application will be described in detail and explained through several specific embodiments.

[0048] In one embodiment, a demagnetization detection method for a permanent magnet motor is provided. This method is applied to a controller for detecting the demagnetization of the permanent magnet motor. The controller can be a microcontroller, control chip, vehicle terminal, or server, etc. The server can be a standalone server or a server cluster composed of multiple servers. It can also be a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, CDN, and big data and artificial intelligence sampling point devices.

[0049] like Figure 1 As shown, the demagnetization detection method for a permanent magnet motor provided in this embodiment includes:

[0050] Step 101: Control the motor winding inductance of the permanent magnet motor to perform energy interaction, and obtain the excitation current component of the permanent magnet motor when the motor winding inductance performs energy interaction.

[0051] Step 102: Based on the excitation current component, the current amplitude of the excitation current component, and the d-axis drive voltage of the permanent magnet motor, obtain the local d-axis inductance of the permanent magnet motor when the motor winding inductance performs energy interaction.

[0052] Step 103: Determine the state of the permanent magnet motor based on the d-axis inductance;

[0053] The states include either a demagnetized state or a non-demagnetized state.

[0054] By controlling the inductance of the permanent magnet motor windings to exchange energy, high-frequency alternating current is generated on the DC bus. The excitation current component of the permanent magnet motor during this energy exchange is acquired. Based on this excitation current component, its amplitude, and the d-axis drive voltage of the permanent magnet motor, the local d-axis inductance is monitored. The change in d-axis inductance is then used to detect demagnetization of the permanent magnet motor. Since the d-axis inductance increases when the permanent magnets are in a demagnetized state, the change in d-axis inductance can effectively detect whether demagnetization has occurred. This allows for demagnetization detection of the permanent magnet motor using existing hardware within the electronic control system, eliminating the need for additional hardware and making demagnetization detection more convenient.

[0055] like Figure 2 As shown, the original electronic control system typically includes a circuit consisting of an IGBT and a permanent magnet motor. The controller can control at least one of the motor winding inductors L1-L3 of the permanent magnet motor to repeatedly perform energy storage and release interactions via the IGBT. When the motor winding inductors perform energy interactions, the excitation current component i of the permanent magnet motor is increased. d High-frequency changes are performed to generate high-frequency alternating current on the DC bus, while simultaneously acquiring the excitation current component i of the permanent magnet motor during energy interaction with the motor winding inductance. d .

[0056] When controlling the energy exchange through the inductance of the permanent magnet motor windings, the permanent magnet motor can be kept stationary. For example, controlling the output torque of the permanent magnet motor to 0 will keep it stationary and prevent vibration.

[0057] As for permanent magnet motors, their output electromagnetic torque T e With excitation current component i d and torque current component i q The relationship is:

[0058]

[0059] Where, n p L represents the extreme logarithm. d L represents the d-axis inductance. q ψ represents the q-axis inductance. f This indicates the flux linkage of the rotor permanent magnet.

[0060] As can be seen from the above relationships, to avoid vibration of the permanent magnet motor while performing demagnetization detection, i.e., to ensure the output torque is close to zero, the torque current component i can be controlled. q =0, thus avoiding the permanent magnet motor from generating torque, keeping the permanent magnet motor in a stationary state. Meanwhile, if Figure 3As shown, the excitation current component i controlling the permanent magnet auger d High-frequency changes generate high-frequency alternating current on the DC bus and acquire the excitation current component i. d .

[0061] After obtaining the excitation current component i d Afterwards, due to the excitation current component i d This includes DC bias current and AC current, namely:

[0062] i d (t)=I d0 +I d,ac sin(2πft)

[0063] Among them, i d0 I is the current offset. d，ac Let f be the current amplitude, f be the current frequency, and t be a certain moment.

[0064] Since the current offset and current frequency are known, the current amplitude of the excitation current component can be determined by the above formula.

[0065] After obtaining the current amplitude of the excitation current component, the excitation current component i can be used to determine the current amplitude. d Current amplitude I d，ac The d-axis drive voltage U of the permanent magnet motor d And the d-axis inductance L of the permanent magnet motor d The relationship between U d (t)=i d (t)R m +L d i' d (t)=i d (t)R m +(2πfL d )I d，ac cos(2πft) is used to obtain the d-axis inductance L of the permanent magnet motor. d .

[0066] Among them, R m This indicates the internal resistance of the permanent magnet motor.

[0067] When the permanent magnet motor is not stationary, the d-axis drive voltage U d Due to the torque of the permanent magnet motor, the d-axis inductance L obtained using the above relationship is affected. d There will be some error. However, when the permanent magnet motor is stationary, the above relationship can accurately determine the excitation current component i. d Current amplitude I d，ac d-axis drive voltage U d and d-axis inductance L dThe correspondence between them. Therefore, to make the subsequently obtained d-axis inductance more accurate and improve the accuracy of demagnetization detection, the inductance can be calculated further based on U when the permanent magnet motor is stationary. d (t)=i d (t)R m +(2πfL d )I d，ac cos(2πft) is used to obtain the d-axis inductance L of the permanent magnet motor. d .

[0068] After obtaining the d-axis inductance L of the permanent magnet motor d Then, the d-axis inductance L can be calculated. d Compare with the preset inductance threshold L d0 Compare the values. When the d-axis inductance L... d Greater than L d0 If the permanent magnet of the motor rotor has demagnetized, a fault is reported; if the d-axis inductance L d Less than or equal to L d0 If the demagnetization fault is not detected, the self-test will be successful.

[0069] To make the demagnetization detection of permanent magnet motors more accurate, the preset inductance threshold is the inductance L along the d-axis when the rotor permanent magnets of the permanent magnet motor are saturated. d0 In addition, the excitation current component I d This can be the d-axis excitation current component I when the rotor permanent magnet of a permanent magnet motor is saturated. d0 Therefore, we can first determine based on U. d,ac =(2πfL) d )I d，ac To obtain the driving voltage U d AC component amplitude U d,ac Then, using the AC component amplitude U d,ac and I d，ac This allows the detection of the excitation current component I. d The excitation current component I along the d-axis when the rotor permanent magnet of a permanent magnet motor is saturated. d0 At that time, the d-axis inductance of the permanent magnet motor

[0070]

[0071] Then, the d-axis inductance The inductance L along the d-axis of a permanent magnet motor when the rotor permanent magnet is saturated. d0 A comparison is performed to determine the state of the permanent magnet motor.

[0072] Among them, the excitation current component I of the d-axis when the rotor permanent magnet of the permanent magnet motor is saturated d0 And the d-axis inductance L of the permanent magnet rotor when the permanent magnet of the permanent magnet motor is saturated.d0 The value can be obtained based on the relationship between d-axis inductance and flux linkage: Pre-detection of I when the rotor permanent magnet is saturated d0 and the I d0 The corresponding d-axis inductance L d0 Then, the L d0 With d-axis inductance Comparison. For example... Figure 4 As shown, since the permanent magnet magnetic field of the permanent magnet motor is oriented in the positive direction of the d-axis, when a positive I is applied... d0 The current increases, and the d-axis magnetic field strengthens. With I... d0 As the current increases, the magnetic materials used in the stator and rotor of a permanent magnet motor, such as silicon steel sheets, easily become saturated, manifesting as a rapid decrease in localized inductance. On the other hand, after the permanent magnet demagnetizes, its magnetic field strength decreases. The more severe the demagnetization of the permanent magnet, the lower the magnetic field strength of the same current. d0 Under current bias, the saturation of the magnetic material decreases, and its local d-axis inductance I... d0 It will increase.

[0073] Therefore, by pre-determining a given I d0 Under bias conditions, the correspondence between the local inductance and flux linkage of the d-axis can be used to detect whether the permanent magnet of the motor rotor has demagnetized, based on the local d-axis inductance measured after power-on. This allows for timely detection of demagnetization of the permanent magnet motor upon power-on.

[0074] The demagnetization detection device for permanent magnet motors provided in this application is described below. The demagnetization detection device for permanent magnet motors described below can be referred to in correspondence with the demagnetization detection method for permanent magnet motors described above.

[0075] In one embodiment, such as Figure 5 As shown, a demagnetization detection device for a permanent magnet motor is provided, comprising:

[0076] The motor control module 210 is used to control the motor winding inductance of the permanent magnet motor to perform energy interaction and to obtain the excitation current component of the permanent magnet motor when the motor winding inductance performs energy interaction.

[0077] The inductance acquisition module 220 is used to acquire the local d-axis inductance of the permanent magnet motor when the motor winding inductance performs energy interaction based on the excitation current component, the current amplitude of the excitation current component and the d-axis drive voltage of the permanent magnet motor.

[0078] The demagnetization detection module 230 is used to determine the state of the permanent magnet motor based on the d-axis inductance.

[0079] The states include either a demagnetized state or a non-demagnetized state.

[0080] By controlling the inductance of the permanent magnet motor windings to exchange energy, high-frequency alternating current is generated on the DC bus. The excitation current component of the permanent magnet motor during this energy exchange is acquired. Based on this excitation current component, its amplitude, and the d-axis drive voltage of the permanent magnet motor, the local d-axis inductance is monitored. The change in d-axis inductance is then used to detect demagnetization of the permanent magnet motor. Since the d-axis inductance increases when the permanent magnets are in a demagnetized state, the change in d-axis inductance can effectively detect whether demagnetization has occurred. This allows for demagnetization detection of the permanent magnet motor using existing hardware within the electronic control system, eliminating the need for additional hardware and making demagnetization detection more convenient.

[0081] In one embodiment, the motor control module 210 is further configured to:

[0082] When controlling the inductance of the motor windings of the permanent magnet motor to exchange energy, the permanent magnet motor is kept in a stationary state.

[0083] In one embodiment, the motor control module 210 is specifically used for:

[0084] The torque current component of the permanent magnet motor is controlled to be zero when the motor winding inductance interacts with energy, so that the permanent magnet motor is in a stationary state.

[0085] In one embodiment, the inductance acquisition module 220 is specifically used for:

[0086] According to U d (t)=i d (t)R m +(2πfL d )I d，ac cos(2πft), obtain the local d-axis inductance L of the permanent magnet motor when the motor winding inductance performs energy interaction. d ;

[0087] Among them, i d R represents the excitation current component. m L represents the internal resistance of the permanent magnet motor. d I represents the d-axis inductance. d，ac The amplitude of the current is represented by t, and t represents a certain moment.

[0088] In one embodiment, the excitation current component is the d-axis excitation current component when the rotor permanent magnet of the permanent magnet motor is saturated.

[0089] In one embodiment, the demagnetization detection module 230 is specifically used for:

[0090] The d-axis inductance is compared with a preset inductance threshold to determine whether the d-axis inductance is greater than the preset inductance threshold.

[0091] If so, determine that the permanent magnet motor is in a demagnetized state;

[0092] Otherwise, the permanent magnet motor is determined to be in an undemagnetized state.

[0093] In one embodiment, the preset inductance threshold is the inductance of the d-axis when the rotor permanent magnet of the permanent magnet motor is saturated.

[0094] Figure 6 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 6 As shown, the electronic device may include: a processor 810, a communication interface 820, a memory 830, and a communication bus 840, wherein the processor 810, the communication interface 820, and the memory 830 communicate with each other via the communication bus 840. The processor 810 can call a computer program in the memory 830 to execute a demagnetization detection method for a permanent magnet motor, such as including:

[0095] The inductance of the motor winding of the permanent magnet motor is controlled to perform energy interaction, and the excitation current component of the permanent magnet motor is obtained when the inductance of the motor winding is performing energy interaction.

[0096] Based on the excitation current component, the current amplitude of the excitation current component, and the d-axis drive voltage of the permanent magnet motor, the local d-axis inductance of the permanent magnet motor during energy interaction in the motor winding inductance is obtained.

[0097] The state of the permanent magnet motor is determined based on the d-axis inductance.

[0098] The current amplitude is determined based on the excitation current component and the current offset of the excitation current component.

[0099] The state includes either a demagnetized state or a non-demagnetized state.

[0100] Furthermore, the logical instructions in the aforementioned memory 830 can be implemented as software functional units and, when sold or used as independent products, 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 a 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 includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of 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.

[0101] On the other hand, embodiments of this application also provide a storage medium, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the demagnetization detection method for permanent magnet motors provided in the above embodiments, for example including:

[0102] The inductance of the motor winding of the permanent magnet motor is controlled to perform energy interaction, and the excitation current component of the permanent magnet motor is obtained when the inductance of the motor winding is performing energy interaction.

[0103] Based on the excitation current component, the current amplitude of the excitation current component, and the d-axis drive voltage of the permanent magnet motor, the local d-axis inductance of the permanent magnet motor during energy interaction in the motor winding inductance is obtained.

[0104] The state of the permanent magnet motor is determined based on the d-axis inductance.

[0105] The current amplitude is determined based on the excitation current component and the current offset of the excitation current component.

[0106] The state includes either a demagnetized state or a non-demagnetized state.

[0107] On the other hand, embodiments of this application also provide a vehicle that includes electronic devices as described in the above embodiments.

[0108] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0109] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for detecting demagnetization of a permanent magnet motor, characterized in that, include: The inductance of the motor winding of the permanent magnet motor is controlled to perform energy interaction, and the excitation current component of the permanent magnet motor is obtained when the inductance of the motor winding is performing energy interaction. Based on the excitation current component, the current amplitude of the excitation current component, and the d-axis drive voltage of the permanent magnet motor, the local d-axis inductance of the permanent magnet motor during energy interaction in the motor winding inductance is obtained. The state of the permanent magnet motor is determined by comparing the d-axis inductance with a preset inductance threshold. The current amplitude is determined based on the excitation current component and the current offset of the excitation current component. The state includes a demagnetized state or a non-demagnetized state, and the preset inductance threshold is the inductance of the d-axis when the rotor permanent magnet of the permanent magnet motor is saturated. The excitation current component is the d-axis excitation current component when the rotor permanent magnet of the permanent magnet motor is saturated. Based on the excitation current component, the current amplitude of the excitation current component, and the d-axis drive voltage of the permanent magnet motor, the local d-axis inductance of the permanent magnet motor during energy interaction in the motor winding inductance is obtained, including: according to The local d-axis inductance of the permanent magnet motor under the action of the excitation current component is obtained when the motor winding inductance undergoes energy interaction. ; in, This represents the excitation current component. This indicates the internal resistance of the permanent magnet motor. This represents the d-axis inductance. The amplitude of the current is represented by t, and t represents a certain moment.

2. The demagnetization detection method for a permanent magnet motor according to claim 1, characterized in that, Also includes: When controlling the inductance of the motor windings of the permanent magnet motor to exchange energy, the permanent magnet motor is kept in a stationary state.

3. The demagnetization detection method for a permanent magnet motor according to claim 2, characterized in that, Controlling the permanent magnet motor to be in a stationary state includes: The torque current component of the permanent magnet motor is controlled to be zero when the motor winding inductance interacts with energy, so that the permanent magnet motor is in a stationary state.

4. The demagnetization detection method for a permanent magnet motor according to claim 1, characterized in that, The state of the permanent magnet motor is determined by comparing the d-axis inductance with a preset inductance threshold, including: The d-axis inductance is compared with a preset inductance threshold to determine whether the d-axis inductance is greater than the preset inductance threshold. If so, determine that the permanent magnet motor is in a demagnetized state; Otherwise, the permanent magnet motor is determined to be in an undemagnetized state.

5. A demagnetization detection device for a permanent magnet motor, characterized in that, include: The motor control module is used to control the energy interaction of the motor winding inductance of the permanent magnet motor and to obtain the excitation current component of the permanent magnet motor when the energy interaction occurs in the motor winding inductance. An inductance acquisition module is used to acquire the local d-axis inductance of the permanent magnet motor when the motor winding inductance interacts with energy, based on the excitation current component, the current amplitude of the excitation current component, and the d-axis drive voltage of the permanent magnet motor. The demagnetization detection module is used to compare the d-axis inductance with a preset inductance threshold to determine the state of the permanent magnet motor. The current amplitude is determined based on the excitation current component and the current offset of the excitation current component. The state includes a demagnetized state or a non-demagnetized state, and the preset inductance threshold is the inductance of the d-axis when the rotor permanent magnet of the permanent magnet motor is saturated. The excitation current component is the d-axis excitation current component when the rotor permanent magnet of the permanent magnet motor is saturated. The inductance acquisition module is specifically used for: according to The local d-axis inductance of the permanent magnet motor under the action of the excitation current component is obtained when the motor winding inductance undergoes energy interaction. ; in, This represents the excitation current component. This indicates the internal resistance of the permanent magnet motor. This represents the d-axis inductance. The amplitude of the current is represented by t, and t represents a certain moment.

6. An electronic device comprising a processor and a memory storing a computer program, characterized in that, When the processor executes the computer program, it implements the demagnetization detection method for the permanent magnet motor according to any one of claims 1 to 4.

7. A vehicle, characterized in that, Including the electronic device as described in claim 6.

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