Permanent magnet synchronous motor rotor demagnetization detection method, device, apparatus and storage medium

Abstract

The application belongs to the technical field of new energy electric drive systems, and particularly relates to a permanent magnet synchronous motor rotor demagnetization detection method, equipment, a device and a storage medium. A permanent magnet synchronous motor rotor demagnetization detection method is applied to permanent magnet synchronous motor rotor demagnetization detection equipment. The equipment comprises a motor controller, a first detection module and a second detection module. The first detection module is used for performing demagnetization detection when the motor is working. The second detection module is used for performing demagnetization detection when the motor is in a non-working state. The method comprises the following steps: the motor controller communicates with a to-be-detected motor, and obtains a working state of the to-be-detected motor; according to the working state of the to-be-detected motor, the first detection module or the second detection module is selected to perform demagnetization detection on the to-be-detected motor, and a detection result is obtained; the detection result is judged to determine whether the rotor of the to-be-detected motor is demagnetized. The permanent magnet synchronous motor can be timely detected and recognized whether it is demagnetized in a normal running or parking state of the permanent magnet synchronous motor start, so that unexpected vehicle driving abnormalities and driving safety risks caused by the driving abnormalities can be avoided.

Description

Technical Field

[0001] This invention belongs to the field of new energy electric drive system technology, specifically relating to a method, equipment, device and storage medium for detecting rotor demagnetization of permanent magnet synchronous motors. Background Technology

[0002] Permanent magnet synchronous motors are widely used in the field of electric vehicles. When a permanent magnet synchronous motor is working, the rotor heats up due to hysteresis loss, eddy current loss and other reasons. When the rotor temperature exceeds the allowable temperature limit of the rotor permanent magnet material for a certain period of time, the rotor permanent magnet material will demagnetize, resulting in a reduction in the motor output torque, which seriously affects the driving performance of electric vehicles and may even cause safety risks. Therefore, it is necessary to detect and identify whether the permanent magnet synchronous motor is demagnetized in a timely manner, so as to avoid unexpected vehicle driving abnormalities and driving safety risks.

[0003] However, because the rotor of a permanent magnet synchronous motor rotates at high speed during operation, it is difficult to install sensors on the motor rotor. Therefore, the rotor of the permanent magnet synchronous motor used in electric vehicles is not demagnetized or protected in the whole vehicle, which poses a driving risk to the whole vehicle. Summary of the Invention

[0004] The purpose of this invention is to provide a method, equipment, device, and storage medium for detecting demagnetization of a permanent magnet synchronous motor rotor. This method can detect and identify whether a permanent magnet synchronous motor in a car is demagnetized in a timely manner, whether the motor is running normally or parked, thereby avoiding unexpected vehicle driving abnormalities and the resulting driving safety risks.

[0005] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, embodiments of this application provide a method for detecting demagnetization of a permanent magnet synchronous motor rotor, applied to a permanent magnet synchronous motor rotor demagnetization detection device. The device includes a motor controller, a first detection module, and a second detection module. The first detection module is used to perform demagnetization detection when the motor is operating, and the second detection module is used to perform demagnetization detection when the motor is not operating. The method includes:

[0007] The motor controller communicates with the motor under test to obtain the operating status of the motor under test;

[0008] Based on the operating state of the motor under test, select either the first detection module or the second detection module to perform demagnetization detection on the motor under test and obtain the detection result;

[0009] The test results are evaluated to determine whether the rotor of the motor under test has demagnetized.

[0010] In conjunction with the first aspect, in some optional embodiments, the motor controller communicates with the motor under test to obtain the operating status of the motor under test, including:

[0011] When the motor under test is working normally, the motor operation flag bit of the motor controller is the first reading;

[0012] When the motor under test is not working, the motor operation flag bit of the motor controller is the second reading.

[0013] In conjunction with the first aspect, in some optional implementations, depending on the operating state of the motor under test, a first detection module or a second detection module is selected to perform demagnetization detection on the motor under test to obtain detection results, including:

[0014] When the motor operation flag is at the first reading, the first detection module is selected to perform demagnetization detection on the motor under test and obtain the detection result.

[0015] When the motor operation flag is the second reading, the second detection module is selected to perform demagnetization detection on the motor under test and obtain the detection result.

[0016] In conjunction with the first aspect, in some optional implementations, the first detection module is selected to perform demagnetization detection on the motor under test, including:

[0017] The first detection module collects the actual DC power of the motor under test, the motor speed and torque when the motor is running normally, and calculates the requested DC power of the motor under test according to the preset efficiency MAP calibration table of the motor system.

[0018] The power deviation ΔP between the actual DC power and the requested DC power is calculated.

[0019] In conjunction with the first aspect, in some optional implementations, a second detection module is selected to perform demagnetization detection on the motor under test, including:

[0020] The second detection module includes a three-phase stator coil circuit with power supply. When the second detection module performs detection, the motor under test is connected in series with the circuit under test and runs. The second detection module collects the requested demagnetization detection current in the circuit and the internal resistance of the power battery in the circuit. Based on the requested demagnetization detection current and the internal resistance of the battery, the module queries a preset first calibration table to obtain the current intermediate parameters.

[0021] The second detection module collects the dynamic voltage across the power battery in the circuit, and based on the dynamic voltage, queries a preset second calibration table to obtain the coefficient α corresponding to the dynamic voltage.

[0022] The actual demagnetization detection current is calculated based on the intermediate current parameter and the coefficient α.

[0023] The current deviation ΔI between the actual demagnetization detection current and the requested demagnetization detection current is calculated.

[0024] In conjunction with the first aspect, in some optional implementations, the detection result is judged to determine whether the rotor of the motor under test is demagnetized, including:

[0025] When the first detection module performs the detection, the power deviation ΔP is compared with the preset power deviation threshold P0.

[0026] If the power deviation ΔP exceeds the power deviation threshold P0, the rotor of the motor under test is determined to be demagnetized; if the power deviation ΔP does not exceed the power deviation threshold P0, the rotor of the motor under test is determined to be undemagnetized.

[0027] In conjunction with the first aspect, in some optional implementations, the detection result is judged to determine whether the rotor of the motor under test is demagnetized, including:

[0028] When the detection is performed by the second detection module, the current deviation ΔI is compared with the preset current deviation threshold I0;

[0029] If the circuit deviation ΔI exceeds the current deviation threshold I0, the rotor of the motor under test is determined to be demagnetized; if the current deviation ΔI does not exceed the current deviation threshold I0, the rotor of the motor under test is determined to be undemagnetized.

[0030] Secondly, this application also provides a permanent magnet synchronous motor rotor demagnetization detection device, applied to a permanent magnet synchronous motor rotor demagnetization detection equipment. The equipment includes a motor controller, a first detection module, and a second detection module. The first detection module is used to perform demagnetization detection when the motor is working, and the second detection module is used to perform demagnetization detection when the motor is not working. The device includes:

[0031] Selection unit: Used to select the first detection module or the second detection module to perform demagnetization detection on the motor under test according to the working status of the motor under test;

[0032] Detection unit: Used to control the first detection module or the second detection module to perform demagnetization detection on the motor under test.

[0033] Thirdly, this application also provides a permanent magnet synchronous motor rotor demagnetization detection device, including a motor controller, a first detection module, a second detection module, and a storage module. The first detection module is used to perform demagnetization detection when the motor is working, and the second detection module is used to perform demagnetization detection when the motor is not working. The storage module stores a computer program. When the computer program is executed by the first detection module or the second detection module, the permanent magnet synchronous motor rotor demagnetization detection device performs the above-described method.

[0034] Fourthly, embodiments of this application also provide a computer-readable storage medium storing a computer program that, when run on a computer, causes the computer to perform the methods described above.

[0035] The invention employing the above technical solution has the following advantages:

[0036] The operating status of the motor under test is determined by the motor controller. When the motor is running normally, the first detection module detects the power deviation ΔP between the actual DC power and the requested DC power. This deviation ΔP is compared with a preset power deviation threshold P0 to determine if the motor is demagnetized. When the motor is stopped, the second detection module connects the motor to an external circuit and detects the current deviation ΔI between the actual demagnetization detection current and the requested demagnetization detection current. This deviation ΔI is compared with a preset current deviation threshold I0 to determine if the motor is demagnetized. This system can promptly detect and identify demagnetization of the permanent magnet synchronous motor during both normal operation and shutdown, thereby avoiding unexpected vehicle driving abnormalities and the resulting driving safety risks. Attached Figure Description

[0037] The present invention can be further illustrated by the non-limiting embodiments given in the accompanying drawings;

[0038] Figure 1 A block diagram of a permanent magnet synchronous motor rotor demagnetization detection device provided in an embodiment of this application.

[0039] Figure 2 This is a flowchart illustrating the demagnetization detection method for a permanent magnet synchronous motor rotor provided in an embodiment of this application.

[0040] Figure 3 A block diagram of a permanent magnet synchronous motor rotor demagnetization detection device provided in an embodiment of this application.

[0041] Icons: 10. Demagnetization detection equipment for permanent magnet synchronous motor rotor; 11. Motor controller; 12. First detection module; 13. Second detection module; 200. Demagnetization detection device for permanent magnet synchronous motor rotor; 210. Selection unit; 220. Detection unit. Detailed Implementation

[0042] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that similar or identical parts are referred to by the same reference numerals in the drawings or description. Implementations not shown or described in the drawings are forms known to those skilled in the art. In addition, directional terms mentioned in the embodiments, such as "up," "down," "top," "bottom," "left," "right," "front," and "back," are only for reference to the directions in the drawings and are not intended to limit the scope of protection of the present invention.

[0043] like Figure 1 As shown, this application embodiment provides a permanent magnet synchronous motor rotor demagnetization detection device 10. The permanent magnet synchronous motor rotor demagnetization detection device 10 may include a motor controller 11, a first detection module 12, a second detection module 13, and a storage module. The first detection module 12 is used to perform demagnetization detection when the motor is working, and the second detection module 13 is used to perform demagnetization detection when the motor is not working.

[0044] In this embodiment, the operating state of the motor under test is first determined by the motor controller 11. When the motor is operating normally, the first detection module 12 detects the power deviation ΔP between the actual DC power and the requested DC power. The power deviation ΔP is compared with a preset power deviation threshold P0 to determine if the motor under test has demagnetized. When the motor is stopped, the second detection module 13 connects the motor to an external circuit and detects the current deviation ΔI between the actual demagnetization detection current and the requested demagnetization detection current. The current deviation ΔI is compared with a preset current deviation threshold I0 to determine if the motor under test has demagnetized. This system can promptly detect and identify whether the permanent magnet synchronous motor is demagnetized, whether it is running normally or stopped, thereby avoiding unexpected vehicle driving abnormalities and the resulting driving safety risks.

[0045] The storage module stores a computer program. When the computer program is executed by the motor controller 11, the first detection module 12, or the second detection module 13, the permanent magnet synchronous motor rotor demagnetization detection device 10 is able to perform the corresponding steps in the following permanent magnet synchronous motor rotor demagnetization detection method.

[0046] like Figure 2 As shown, this application also provides a method for detecting the demagnetization of a permanent magnet synchronous motor rotor. The method for detecting the demagnetization of a permanent magnet synchronous motor rotor may include the following steps:

[0047] Step 110: The motor controller 11 communicates with the motor under test to obtain the operating status of the motor under test;

[0048] Step 120: Based on the working state of the motor under test, select the first detection module 12 or the second detection module 13 to perform demagnetization detection on the motor under test and obtain the detection result;

[0049] Step 130: Determine whether the rotor of the motor under test has demagnetized based on the test results.

[0050] In this embodiment, the motor controller 11 communicates with the motor under test via a bus signal to obtain the operating status of the motor under test. When the motor under test is running normally, the first detection module 12 detects the power deviation ΔP between the actual DC power and the requested DC power to determine whether the motor under test is demagnetized. When the motor under test is stopped, the second detection module 13 connects the motor under test to an external circuit and detects the current deviation ΔI between the actual demagnetization detection current and the requested demagnetization detection current to determine whether the motor under test is demagnetized.

[0051] As an optional implementation, the motor controller 11 communicates with the motor under test to obtain the operating status of the motor under test, including:

[0052] When the motor under test is working normally, the motor operation flag bit of the motor controller 11 is the first reading;

[0053] When the motor under test is not working, the motor operation flag bit of the motor controller 11 is the second value.

[0054] In this embodiment, the motor controller 11 communicates with the motor under test via a bus signal. When the motor under test is working normally, the motor operation flag bit of the motor controller 11 shows a first value; when the motor under test is not working, the motor operation flag bit of the motor controller 11 shows a second value.

[0055] As an optional implementation, depending on the operating state of the motor under test, either the first detection module 12 or the second detection module 13 is selected to perform demagnetization detection on the motor under test, and the detection results are obtained, including:

[0056] When the motor operation flag is at the first reading, the first detection module 12 is selected to perform demagnetization detection on the motor under test and obtain the detection result.

[0057] When the motor operation flag is the second reading, the second detection module 13 is selected to perform demagnetization detection on the motor under test and obtain the detection result.

[0058] In this embodiment, when the motor under test is working normally, the first detection module 12 is selected to perform demagnetization detection on the motor under test; when the motor under test is not working, the second detection module 13 is selected to perform demagnetization detection on the motor under test.

[0059] As an optional implementation, the first detection module 12 is selected to perform demagnetization detection on the motor under test, including:

[0060] The first detection module 12 collects the actual DC power of the motor under test, the motor speed and torque when the motor is running normally, and calculates the requested DC power of the motor under test according to the preset efficiency MAP calibration table of the motor system.

[0061] The power deviation ΔP between the actual DC power and the requested DC power is calculated.

[0062] In this embodiment, the required DC power of the motor under test is obtained by consulting the efficiency MAP calibration table of the motor system using the motor speed and torque during normal operation. The absolute value of the difference between the actual DC power and the required DC power is the power deviation ΔP.

[0063] As an optional implementation, the detection results are judged to determine whether the rotor of the motor under test has demagnetized, including:

[0064] When the first detection module 12 performs detection, the power deviation ΔP is compared with the preset power deviation threshold P0;

[0065] If the power deviation ΔP exceeds the power deviation threshold P0, the rotor of the motor under test is determined to be demagnetized; if the power deviation ΔP does not exceed the power deviation threshold P0, the rotor of the motor under test is determined to be undemagnetized.

[0066] As an optional implementation, the second detection module 13 is selected to perform demagnetization detection on the motor under test, including:

[0067] The second detection module 13 includes a three-phase stator coil circuit with power supply. When the second detection module 13 performs detection, the motor under test is connected in series in the circuit under test and runs. The second detection module 13 collects the requested demagnetization detection current in the circuit and the internal resistance of the power battery in the circuit. Based on the requested demagnetization detection current and the internal resistance of the battery, the module queries a preset first calibration table to obtain the current intermediate parameters.

[0068] The second detection module 13 collects the dynamic voltage across the power battery in the circuit, and obtains the coefficient α corresponding to the dynamic voltage by querying a preset second calibration table based on the dynamic voltage.

[0069] The actual demagnetization detection current is calculated based on the intermediate current parameter and the coefficient α.

[0070] The current deviation ΔI between the actual demagnetization detection current and the requested demagnetization detection current is calculated.

[0071] In this embodiment, the first calibration table is an IR chart, with the horizontal axis representing the requested heating current value and the vertical axis representing the battery internal resistance. At the battery's rated voltage U... N Next, an intermediate current parameter calibration test was conducted to obtain all the heating current request values ​​and intermediate current parameter values ​​under the battery internal resistance combination listed in the table.

[0072] The second calibration table shows the effect of battery dynamic voltage on pulse current, obtained through calibration tests. This is done when the battery voltage is U... x Below, the battery bus current is set to the rated current, and the battery internal resistance is set to the nominal resistance R. N The shaft current is calibrated, and U is obtained through calculation. x The corresponding coefficient α x .

[0073] Understandably, the three-phase stator coil circuit with power supply consists of a power battery, a power switch, and the three-phase stator coil, forming a demagnetization detection circuit. When the power switch connected to the three-phase stator coil is turned on, a current related to the stator inductance and the on-time will be generated, and energy will be stored in the stator inductor. When the power switch is turned off, the current stored in the stator inductor will flow back to the power battery through the freewheeling diode. Through the alternation of these two moments, a pulse current can be generated across the power battery. This allows the second detection module 13 to collect the requested demagnetization detection current, the battery's internal resistance, and the dynamic voltage across the battery from the acquisition circuit. The intermediate current parameters and coefficient α are obtained by looking up the first and second calibration tables, respectively, and the actual demagnetization detection current is calculated.

[0074] Actual demagnetization detection current = intermediate current parameter * α

[0075] The absolute value of the difference between the actual demagnetization detection current and the requested demagnetization detection current is used to calculate the current deviation ΔI.

[0076] As an optional implementation, the detection results are judged to determine whether the rotor of the motor under test has demagnetized, including:

[0077] When detection is performed by the second detection module 13, the current deviation ΔI is compared with the preset current deviation threshold I0;

[0078] If the circuit deviation ΔI exceeds the current deviation threshold I0, the rotor of the motor under test is determined to be demagnetized; if the current deviation ΔI does not exceed the current deviation threshold I0, the rotor of the motor under test is determined to be undemagnetized.

[0079] like Figure 3 As shown, this application also provides a permanent magnet synchronous motor rotor demagnetization detection device 200. The permanent magnet synchronous motor rotor demagnetization detection device 200 includes at least one software function module that can be stored in a storage module or embedded in the operating system (OS) of the permanent magnet synchronous motor rotor demagnetization detection device 10 in the form of software or firmware. The motor controller 11, the first detection module 12, and the second detection module 13 are used to execute executable modules stored in the storage module, such as the software function modules and computer programs included in the permanent magnet synchronous motor rotor demagnetization detection device 200.

[0080] The permanent magnet synchronous motor rotor demagnetization detection device 200 includes a selection unit 210 and a detection unit 220. The functions of each unit are as follows:

[0081] Selection unit 210: used to select the first detection module 12 or the second detection module 13 to perform demagnetization detection on the motor under test according to the working status of the motor under test;

[0082] Detection unit 220: used to control the first detection module 12 or the second detection module 13 to perform demagnetization detection on the motor under test.

[0083] In this embodiment, the storage module can be, but is not limited to, random access memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, etc. In this embodiment, the storage module can be used to store the operating state of the motor under test, a preset motor system efficiency MAP calibration table, the calculated power deviation ΔP, a preset first calibration table, a preset second calibration table, the calculated current deviation ΔI, a preset power deviation threshold P0, and a preset current deviation threshold I0, etc. Of course, the storage module can also be used to store a program, which the processing module executes upon receiving an execution instruction.

[0084] Understandable, Figure 1 The permanent magnet synchronous motor rotor demagnetization detection device 10 shown is only a schematic diagram. The permanent magnet synchronous motor rotor demagnetization detection device 10 may also include components that are more... Figure 1 More components are shown. Figure 1 The components shown can be implemented using hardware, software, or a combination thereof.

[0085] It should be noted that those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process of the permanent magnet synchronous motor rotor demagnetization detection device 10 and the permanent magnet synchronous motor rotor demagnetization detection apparatus 200 described above can be referred to the corresponding process of each step in the aforementioned method, and will not be elaborated further here.

[0086] This application also provides a computer-readable storage medium. The computer-readable storage medium stores a computer program that, when executed on a computer, causes the computer to perform the braking control method as described in the above embodiments.

[0087] Based on the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by hardware or by using software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of this application can be embodied in the form of a software product. The software product can be stored in a non-volatile storage medium (such as CD-ROM, USB flash drive, mobile hard drive, etc.) and includes several instructions to cause a computer device (such as a personal computer, braking device, or network device, etc.) to execute the methods described in the various implementation scenarios of this application.

[0088] In summary, this application provides a method, apparatus, device, and storage medium for detecting rotor demagnetization of a permanent magnet synchronous motor. In this solution, the motor controller 11 determines the operating state of the motor under test. When the motor is operating normally, the first detection module 12 detects the power deviation ΔP between the actual DC power and the requested DC power. The power deviation ΔP is compared with a preset power deviation threshold P0 to determine if the motor is demagnetized. When the motor is stopped, the second detection module 13 connects the motor to an external circuit and detects the current deviation ΔI between the actual demagnetization detection current and the requested demagnetization detection current. The current deviation ΔI is compared with a preset current deviation threshold I0 to determine if the motor is demagnetized. This method can promptly detect and identify whether the permanent magnet synchronous motor is demagnetized, whether it is running normally or stopped, thereby avoiding unexpected vehicle driving abnormalities and the resulting driving safety risks.

[0089] In the embodiments provided in this application, it should be understood that the disclosed apparatus, systems, and methods can also be implemented in other ways. The apparatus, systems, and methods embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code, which includes one or more executable instructions for implementing a specified logical function. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions. Furthermore, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0090] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for detecting rotor demagnetization in a permanent magnet synchronous motor, characterized in that: A demagnetization detection device for permanent magnet synchronous motor rotors is provided. The device includes a motor controller, a first detection module, and a second detection module. The first detection module performs demagnetization detection when the motor is operating, and the second detection module performs demagnetization detection when the motor is not operating. The method includes: The motor controller communicates with the motor under test to obtain the operating status of the motor under test; Based on the operating state of the motor under test, select either the first detection module or the second detection module to perform demagnetization detection on the motor under test and obtain the detection result; The test results are evaluated to determine whether the rotor of the motor under test has demagnetized. Selecting the first detection module to perform demagnetization detection on the motor under test includes: The first detection module collects the actual DC power of the motor under test, the motor speed and torque when the motor is running normally, and calculates the requested DC power of the motor under test according to the preset efficiency MAP calibration table of the motor system. The power deviation ΔP between the actual DC power and the requested DC power is calculated. Selecting the second detection module to perform demagnetization detection on the motor under test includes: The second detection module includes a three-phase stator coil circuit with power supply. When the second detection module performs detection, the motor under test is connected in series with the three-phase stator coil circuit and runs. The second detection module collects the requested demagnetization detection current in the circuit and the internal resistance of the power battery in the circuit. Based on the requested demagnetization detection current and the internal resistance of the battery, the module queries a preset first calibration table to obtain the current intermediate parameters. The second detection module collects the dynamic voltage across the power battery in the circuit, and based on the dynamic voltage, queries a preset second calibration table to obtain the coefficient α corresponding to the dynamic voltage. The actual demagnetization detection current is calculated based on the intermediate current parameter and the coefficient α. The current deviation ΔI between the actual demagnetization detection current and the requested demagnetization detection current is calculated. The test results are evaluated to determine whether the rotor of the motor under test has demagnetized, including: When the first detection module performs the detection, the power deviation ΔP is compared with the preset power deviation threshold P0. If the power deviation ΔP exceeds the power deviation threshold P0, the rotor of the motor under test is determined to be demagnetized; if the power deviation ΔP does not exceed the power deviation threshold P0, the rotor of the motor under test is determined to be undemagnetized. When the detection is performed by the second detection module, the current deviation ΔI is compared with the preset current deviation threshold I0; If the current deviation ΔI exceeds the current deviation threshold I0, the rotor of the motor under test is determined to be demagnetized; if the current deviation ΔI does not exceed the current deviation threshold I0, the rotor of the motor under test is determined to be undemagnetized.

2. The method for detecting rotor demagnetization of a permanent magnet synchronous motor according to claim 1, characterized in that: The motor controller communicates with the motor under test to obtain the operating status of the motor under test, including: When the motor under test is working normally, the motor operation flag bit of the motor controller is the first reading; When the motor under test is not working, the motor operation flag bit of the motor controller is the second reading.

3. The method for detecting rotor demagnetization of a permanent magnet synchronous motor according to claim 2, characterized in that: Based on the operating state of the motor under test, either the first detection module or the second detection module is selected to perform demagnetization detection on the motor under test, and the detection results are obtained, including: When the motor operation flag is at the first reading, the first detection module is selected to perform demagnetization detection on the motor under test and obtain the detection result. When the motor operation flag is the second reading, the second detection module is selected to perform demagnetization detection on the motor under test and obtain the detection result.

4. A device for detecting rotor demagnetization of a permanent magnet synchronous motor, characterized in that: A demagnetization detection device for permanent magnet synchronous motor rotors is provided. The device includes a motor controller, a first detection module, and a second detection module. The first detection module performs demagnetization detection when the motor is operating, and the second detection module performs demagnetization detection when the motor is not operating. The device includes: Selection unit: used to select the first detection module or the second detection module to perform demagnetization detection on the motor under test according to the working status of the motor under test; Detection unit: used to control the first detection module or the second detection module to perform demagnetization detection on the motor under test; Selecting the first detection module to perform demagnetization detection on the motor under test includes: The first detection module collects the actual DC power of the motor under test, the motor speed and torque when the motor is running normally, and calculates the requested DC power of the motor under test according to the preset efficiency MAP calibration table of the motor system. The power deviation ΔP between the actual DC power and the requested DC power is calculated. Selecting the second detection module to perform demagnetization detection on the motor under test includes: The second detection module includes a three-phase stator coil circuit with power supply. When the second detection module performs detection, the motor under test is connected in series with the three-phase stator coil circuit and runs. The second detection module collects the requested demagnetization detection current in the circuit and the internal resistance of the power battery in the circuit. Based on the requested demagnetization detection current and the internal resistance of the battery, the module queries a preset first calibration table to obtain the current intermediate parameters. The second detection module collects the dynamic voltage across the power battery in the circuit, and based on the dynamic voltage, queries a preset second calibration table to obtain the coefficient α corresponding to the dynamic voltage. The actual demagnetization detection current is calculated based on the intermediate current parameter and the coefficient α. The current deviation ΔI between the actual demagnetization detection current and the requested demagnetization detection current is calculated. The test results are evaluated to determine whether the rotor of the motor under test has demagnetized, including: When the first detection module performs the detection, the power deviation ΔP is compared with the preset power deviation threshold P0. If the power deviation ΔP exceeds the power deviation threshold P0, the rotor of the motor under test is determined to be demagnetized; if the power deviation ΔP does not exceed the power deviation threshold P0, the rotor of the motor under test is determined to be undemagnetized. When the detection is performed by the second detection module, the current deviation ΔI is compared with the preset current deviation threshold I0; If the current deviation ΔI exceeds the current deviation threshold I0, the rotor of the motor under test is determined to be demagnetized; if the current deviation ΔI does not exceed the current deviation threshold I0, the rotor of the motor under test is determined to be undemagnetized.

5. A permanent magnet synchronous motor rotor demagnetization detection device, characterized in that: The device includes a motor controller, a first detection module, a second detection module, and a storage module. The first detection module is used to perform demagnetization detection when the motor is working, and the second detection module is used to perform demagnetization detection when the motor is not working. The storage module stores a computer program. When the computer program is executed by the first detection module or the second detection module, the permanent magnet synchronous motor rotor demagnetization detection device performs the method as described in any one of claims 1-3.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when run on a computer, causes the computer to perform the method as described in any one of claims 1-3.

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