Method, device and system for detecting state of permanent magnet in permanent magnet synchronous motor

Abstract

The present invention relates to the technical field of measuring magnetic variables, and proposes a method, device and system for detecting the state of a permanent magnet in a permanent magnet synchronous motor, including: obtaining the degree of power loss of the motor in each operating period according to the difference between the rotor speed data of the motor in each operating period and the rated speed data of the motor rotor; obtaining the degree of motor execution deviation of the motor in each operating period according to the periodic hysteresis and power loss degree between the motor shaft and the three-phase alternating current in each operating period; obtaining the degree of demagnetization performance of the motor in each operating period according to the degree of motor execution deviation and magnetic field uniformity in each operating period; obtaining the demagnetization state detection index of the motor permanent magnet according to the demagnetization state detection index of the motor; and performing state detection on the motor permanent magnet based on the demagnetization state detection index. The present invention improves the accuracy of the permanent magnet state detection result.

Description

Technical Field

[0001] The present invention relates to the technical field of measuring magnetic variables, and in particular to a method, device and system for detecting the state of a permanent magnet in a permanent magnet synchronous motor. Background Art

[0002] A permanent magnet synchronous motor is a motor that uses the interaction between the magnetic field generated by permanent magnets and the magnetic field generated by electric current to realize the operation of the motor. The core structure of the motor is a stator that generates a rotating magnetic field and a rotor that carries permanent magnets. A three-phase alternating current is passed into the stator to generate a rotating magnetic field. The rotating magnetic field and the magnetic field of the permanent magnet produce a magnetic force of repulsion and attraction. The permanent magnet drives the rotor to rotate under the action of the magnetic force, and then the electrical energy is converted into mechanical energy. In actual use, if the motor is in high temperature and high power operation for a long time, the permanent magnet will experience demagnetization, which increases the risk of the motor.

[0003] Traditional methods often use multi-pole magnetic ring measuring devices to detect the abnormal demagnetization state of the internal permanent magnets of permanent magnet synchronous motors when they are running. The demagnetization of permanent magnets will cause the permanent magnets to generate an uneven magnetic field. When the magnetic ring measuring device measures the uniformity of the magnetic field near the permanent magnets of the motor, the worse the magnetic field uniformity, the higher the degree of demagnetization of the permanent magnets. In actual scenarios, the unbalanced magnetic field generated by the demagnetization of permanent magnets will cause unbalanced magnetic force on the motor rotor, thereby generating vibration. The vibration will interfere with the uniformity of the magnetic field generated by the permanent magnet, resulting in inaccurate detection results of the demagnetization state of the permanent magnet reflected by the magnetic field uniformity directly read by the traditional magnetic ring. Summary of the invention

[0004] The present invention provides a method, device and system for detecting the state of a permanent magnet in a permanent magnet synchronous motor, so as to solve the problem that the magnetic field imbalance generated by the demagnetization of the permanent magnet in actual scenarios will cause the magnetic force on the motor rotor to be unbalanced, thereby generating vibration. The vibration will interfere with the uniformity of the magnetic field generated by the permanent magnet, resulting in inaccurate detection results of the demagnetization state of the permanent magnet reflected by the magnetic field uniformity directly read by the traditional magnetic ring. The technical solutions adopted are as follows:

[0005] The present invention proposes a method for detecting the state of a permanent magnet in a permanent magnet synchronous motor, the method comprising the following steps:

[0006] Acquire the rated speed data of the motor rotor, as well as the rotor vibration data and rotor speed data of the motor in several operating periods;

[0007] According to the change of the rotor vibration data of the motor in each operating period, the severity of the rotor vibration of the motor in each operating period is obtained; according to the difference between the rotor speed data of the motor in each operating period, the uniformity of the rotor speed of the motor in each operating period is obtained; according to the uniformity of the rotor speed and the severity of the rotor vibration of the motor in each operating period, the uniformity of the magnetic field of the motor in each operating period is obtained;

[0008] According to the difference between the rotor speed data of the motor in each operating period and the rated speed data of the motor rotor, the power loss degree of the motor in each operating period is obtained; all current cycle periods in each operating period are obtained; according to the rotor speed data of the motor in the current cycle period in each operating period, the periodic hysteresis between the motor shaft and the three-phase alternating current in each operating period is obtained; according to the periodic hysteresis and power loss degree of the motor shaft and the three-phase alternating current in each operating period, the motor execution deviation degree of the motor in each operating period is obtained; according to the motor execution deviation degree and magnetic field uniformity of the motor in each operating period, the demagnetization performance degree of the motor in each operating period is obtained; according to the demagnetization performance degree of the motor in different operating periods, the demagnetization state detection index of the motor permanent magnet is obtained;

[0009] The state of the permanent magnet of the motor is detected based on the demagnetization state detection index.

[0010] Preferably, the method of obtaining the vibration severity of the rotor of the motor in each operating period according to the change of the rotor vibration data of the motor in each operating period includes the following specific methods:

[0011] For the motor In the running period, the running period is used as the horizontal coordinate and the rotor vibration data is used as the vertical coordinate to construct a two-dimensional coordinate system. The rotor vibration data in the running period is input into the two-dimensional coordinate system to obtain the motor in the first Rotor vibration curve within a running period;

[0012] Put the motor in The normalized value of the product of the mean value of the rotor vibration data of all data points on the rotor vibration curve within the running period and the standard deviation of the rotor vibration data of all data points is used as the motor in the first The severity of rotor vibration during a certain operating period.

[0013] Preferably, the method of obtaining the uniformity of the rotor speed of the motor in each operating period according to the difference between the rotor speed data of the motor in each operating period includes the following specific methods:

[0014] For The first At this moment, the motor The first The rotor speed data at the moment is consistent with the motor speed at the The absolute value of the difference between the mean values ​​of the rotor speed data at all times in the operation period is recorded as The speed difference value at the moment; the motor is The inverse of the mean of the speed difference values ​​at all times in the running period is taken as the speed difference of the motor at the The uniformity of the rotor speed within a certain operating period.

[0015] Preferably, the method of obtaining the uniformity of the magnetic field of the motor in each operating period according to the uniformity of the rotor speed and the intensity of the rotor vibration in each operating period includes the following specific methods:

[0016] Put the motor in The inverse of the rotor vibration severity during the first operating period is related to the motor The normalized value of the product of the rotor speed uniformity within the running period is used as the motor The uniformity of the magnetic field during an operation period.

[0017] Preferably, the method of obtaining the power loss degree of the motor in each operating period according to the difference between the rotor speed data of the motor in each operating period and the rated speed data of the motor rotor includes the following specific methods:

[0018] Put the motor in The ratio between the mean value of the rotor speed data at all times in the running period and the rated speed data of the motor rotor is used as the ratio of the motor speed at the first The degree of power loss during an operating period.

[0019] Preferably, the step of obtaining the periodic hysteresis between the motor shaft and the three-phase alternating current in each operating period according to the rotor speed data in the current cycle period of the motor in each operating period includes the following specific methods:

[0020] For For any current cycle segment in the operation time segments, the product of the average value of the rotor speed data at all times in the any current cycle segment and the current cycle length of the motor is recorded as the rotation distance of the motor shaft in the any current cycle segment; the ratio of the rotation distance of the motor shaft in the any current cycle segment to the circumference of the motor shaft is recorded as the rotation period proportion of the motor shaft in the any current cycle segment;

[0021] The first The ratio of the average of the motor shaft rotation period proportions in all current cycle segments in the running time period to the motor current cycle length is used as the motor in the first The periodic lag between the shaft and the three-phase alternating current within an operating period.

[0022] Preferably, the motor execution deviation degree of the motor in each operating period is obtained according to the periodic hysteresis and power loss degree between the motor shaft and the three-phase alternating current in each operating period, and the specific method includes:

[0023] Put the motor in The periodic hysteresis between the shaft and the three-phase alternating current in the first operating period is The product of the power loss degree in the operation period is taken as the power loss of the motor in the first The degree of motor execution deviation within a running period.

[0024] Preferably, the method of obtaining the demagnetization state detection index of the permanent magnet of the motor according to the demagnetization performance degree of the motor in different operating periods includes the following specific methods:

[0025] The last running period is recorded as the real-time running period; all running periods except the real-time running period are recorded as the historical running period;

[0026] For any historical operation period, the absolute value of the difference between the serial number of the any historical operation period and the real-time operation period is recorded as the time difference of the any historical operation period; the normalized value of the product of the reciprocal of the time difference of the any historical operation period and the demagnetization performance degree of the any historical operation period is recorded as the demagnetization performance degree prediction factor of the any historical operation period; the average value of the demagnetization performance degree prediction factors of all historical operation periods is taken as the demagnetization performance prediction value of the motor;

[0027] The ratio of the demagnetization performance degree of the motor in the real-time operation period to the predicted value of the demagnetization performance of the motor is used as the demagnetization state detection index of the permanent magnet of the motor.

[0028] The present invention also proposes a permanent magnet state detection system for a permanent magnet synchronous motor, the system comprising a memory, a processor, and a computer program stored in the memory and running on the processor, and the processor implements the steps of the above method when executing the computer program.

[0029] The present invention also proposes a permanent magnet state detection device for a permanent magnet synchronous motor, the device comprising:

[0030] A motor data acquisition module, a demagnetization state detection index acquisition module and a permanent magnet state detection module. The motor data acquisition module is used to obtain the rated speed data of the motor rotor, as well as the rotor vibration data and rotor speed data of the motor in several operating time periods. The demagnetization state detection index acquisition module implements the steps of the above method by calling a computer program to obtain the demagnetization state detection index of the motor permanent magnet. The permanent magnet state detection performs state detection on the motor permanent magnet based on the demagnetization state detection index.

[0031] The beneficial effects of the present invention are as follows: the present invention obtains the power loss degree of the motor in each operating period according to the difference between the rotor speed data of the motor in each operating period and the rated speed data of the motor rotor; obtains all current cycle periods in each operating period; obtains the periodic hysteresis between the motor shaft and the three-phase alternating current in each operating period according to the rotor speed data of the motor in the current cycle period in each operating period; obtains the motor execution deviation degree of the motor in each operating period according to the periodic hysteresis and power loss degree of the motor shaft and the three-phase alternating current in each operating period; obtains the demagnetization performance degree of the motor in each operating period according to the motor execution deviation degree and magnetic field uniformity of the motor in each operating period; obtains the demagnetization state detection index of the permanent magnet of the motor according to the demagnetization performance degree of the motor in different operating periods;

[0032] The state of the motor permanent magnet is detected based on the demagnetization state detection index; by combining the vibration characteristics of the motor rotor and the motor parameter execution deviation, a more accurate demagnetization state detection index of the motor permanent magnet is obtained; thereby improving the accuracy of the permanent magnet state detection result. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0034] Figure 1 It is a flow chart of the steps of the method for detecting the state of a permanent magnet in a permanent magnet synchronous motor according to the present invention;

[0035] Figure 2 The present invention is a flow chart of characteristic relationships of a method for detecting a state of a permanent magnet in a permanent magnet synchronous motor. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] See also Figure 1 , which shows a flow chart of a method for detecting the state of a permanent magnet in a permanent magnet synchronous motor provided by an embodiment of the present invention, the method comprising the following steps:

[0038] Step S001: Acquire the rated speed data of the motor rotor, as well as the rotor vibration data and rotor speed data of the motor in several operating time periods.

[0039] It should be noted that permanent magnet synchronous motors are often used as electric motors in the fields of industrial control and automotive drive. Their internal core structure is a stator winding and a rotor. When the permanent magnet synchronous motor is running, a three-phase power supply inputs a three-phase alternating current to the stator winding through a transmission line. The three-phase alternating current forms a rotating magnetic field in the stator. The amplitude of the rotating magnetic field remains unchanged, and the direction of the magnetic field changes at a constant angular velocity. When the motor is running, the magnetic field of the permanent magnet itself and the rotating magnetic field generated by the three-phase current produce a repulsive and attracted effect. Then, the permanent magnet is rotated with the rotating magnetic field under the action of magnetic force, and then the permanent magnet drives the rotor to rotate, converting electrical energy into mechanical energy.

[0040] When the motor works in a high temperature and high power state for a long time, the permanent magnet may demagnetize. When the degree of demagnetization is too large, the conversion efficiency of the motor will be significantly reduced. Therefore, the demagnetization phenomenon of the permanent magnet of the motor needs to be detected. Since the demagnetization of the permanent magnet will destroy the uniformity of the surrounding magnetic field, the traditional method often collects the magnetic field uniformity near the permanent magnet of the motor through a multi-pole magnetic ring measuring device, and reflects the abnormal demagnetization state of the permanent magnet based on the read magnetic field uniformity. However, in actual scenarios, there is a large detection error in the permanent magnet state reflected only by the magnetic field uniformity directly read by the multi-pole magnetic ring measuring device. Therefore, this embodiment detects the abnormal demagnetization state of the permanent magnet in the permanent magnet synchronous motor in combination with the scenario characteristics.

[0041] Specifically, one hour is an operating period. Each time, the rotor vibration data in each operating period is obtained through the internal vibration sensor of the permanent magnet synchronous motor, and the rotor speed data in each operating period is obtained through the internal speed monitoring module of the motor. A total of 100 hours of data is collected; the rated speed data of the motor rotor is obtained through the equipment parameter information of the permanent magnet synchronous motor.

[0042] At this point, the rated speed data of the motor rotor, as well as the rotor vibration data and rotor speed data of the motor in several operating periods are obtained.

[0043] Step S002, according to the change of the rotor vibration data of the motor in each operating period, obtain the rotor vibration severity of the motor in each operating period; according to the difference between the rotor speed data of the motor in each operating period, obtain the rotor speed uniformity of the motor in each operating period; according to the rotor speed uniformity and the rotor vibration severity of the motor in each operating period, obtain the magnetic field uniformity of the motor in each operating period.

[0044] It should be noted that when the permanent magnet is demagnetized, the uniformity of its own magnetic field will be destroyed, which will lead to differences in the interaction forces between the permanent magnet regions with different magnetic properties and the rotating magnetic field. The difference in interaction forces causes an imbalance in the rotor force, which further causes the rotor to vibrate during rotation. Therefore, the vibration performance of the rotor in the permanent magnet synchronous motor reflects the uniformity of the permanent magnet's magnetic field.

[0045] Preferably, in one embodiment of the present invention, according to the change of the rotor vibration data of the motor in each operating period, a specific method for obtaining the severity of the rotor vibration of the motor in each operating period is as follows:

[0046] For the motor In the running period, the running period is used as the horizontal coordinate and the rotor vibration data is used as the vertical coordinate to construct a two-dimensional coordinate system. The rotor vibration data in the running period is input into the two-dimensional coordinate system to obtain the motor in the first Rotor vibration curve within a running period;

[0047] Put the motor in The normalized value of the product of the mean value of the rotor vibration data of all data points on the rotor vibration curve within the running period and the standard deviation of the rotor vibration data of all data points is used as the motor in the first The severity of rotor vibration during each operating period;

[0048] The specific formula is:

[0049]

[0050] In the formula, Indicates that the motor is The severity of rotor vibration during each operating period; Indicates that the motor is The mean value of the rotor vibration data of all data points on the rotor vibration curve within an operation period; Indicates that the motor is The standard deviation of the rotor vibration data of all data points on the rotor vibration curve within an operating period; represents the linear normalization function.

[0051] It should be noted that the motor The larger the mean value of the rotor vibration data in a running period, the greater the vibration amplitude. The larger the standard deviation of the rotor vibration data in a running period, the more it indicates that the motor The more severe the vibration is during the operation period.

[0052] Preferably, in one embodiment of the present invention, according to the difference between the rotor speed data of the motor in each operating period, a specific method for obtaining the uniformity of the rotor speed of the motor in each operating period is as follows:

[0053] For The first At this moment, the motor The first The rotor speed data at the moment is consistent with the motor speed at the The absolute value of the difference between the mean values ​​of the rotor speed data at all times in the operation period is recorded as The speed difference value at the moment; the motor is The inverse of the mean of the speed difference values ​​at all times in the running period is taken as the speed difference of the motor at the The uniformity of rotor speed within a certain operating period;

[0054] The specific formula is:

[0055]

[0056] In the formula, Indicates that the motor is The uniformity of rotor speed within a certain operating period; Indicates The number of all moments in a running period; Indicates that the motor is The first The rotor speed data at each moment; Indicates that the motor is The mean value of the rotor speed data at all times within an operating period; Indicates taking the absolute value.

[0057] Preferably, in one embodiment of the present invention, the motor The less severe the rotor vibration is during an operation period, the The greater the uniformity of the rotor speed in each operating period, the more uniform the magnetic field distribution near the permanent magnet of the motor is; then according to the uniformity of the rotor speed and the intensity of the rotor vibration in each operating period, the specific method for obtaining the uniformity of the magnetic field of the motor in each operating period is:

[0058] Put the motor in The inverse of the rotor vibration severity during the first operating period is related to the motor The normalized value of the product of the rotor speed uniformity within the running period is used as the motor The uniformity of the magnetic field during the operation period;

[0059] The specific formula is:

[0060]

[0061] In the formula, Indicates that the motor is The uniformity of the magnetic field during the operation period; Indicates that the motor is The uniformity of rotor speed within a certain operating period; Indicates that the motor is The severity of rotor vibration during each operating period; represents the linear normalization function.

[0062] At this point, the uniformity of the magnetic field of the motor in each operating period is obtained.

[0063] Step S003, according to the difference between the rotor speed data of the motor in each operating period and the rated speed data of the motor rotor, obtain the power loss degree of the motor in each operating period; obtain all current cycle periods in each operating period; according to the rotor speed data of the motor in the current cycle period in each operating period, obtain the periodic hysteresis between the motor shaft and the three-phase alternating current in each operating period; according to the periodic hysteresis and power loss degree between the motor shaft and the three-phase alternating current in each operating period, obtain the motor execution deviation degree of the motor in each operating period; according to the motor execution deviation degree and magnetic field uniformity of the motor in each operating period, obtain the demagnetization performance degree of the motor in each operating period; according to the demagnetization performance degree of the motor in different operating periods, obtain the demagnetization state detection index of the permanent magnet of the motor.

[0064] It should be noted that when the permanent magnet is demagnetized, the degradation of its magnetism causes the interaction force between the permanent magnet and the rotating magnetic field to weaken. At the same time, the vibration caused by demagnetization will cause redundant energy consumption, which in turn causes kinetic energy loss in the permanent magnet synchronous motor during operation. Therefore, the motor is operated at the rated three-phase alternating current, and the degree of motor power loss is obtained based on the difference between the actual speed and the rated speed of the motor. The degree of motor execution deviation is then obtained by combining the periodic lag between the shaft and the three-phase alternating current, and the degree of demagnetization of the permanent magnet is obtained by combining the uniformity of the magnetic field.

[0065] Preferably, in one embodiment of the present invention, if the average value of the rotor speed data of the motor in each operating period is compared with the rated speed of the motor, the slower the motor is, the more likely the permanent magnet is to be demagnetized, resulting in greater power loss of the motor; based on the difference between the rotor speed data of the motor in each operating period and the rated speed data of the motor rotor, the specific method for obtaining the power loss degree of the motor in each operating period is as follows:

[0066] Put the motor in The ratio between the mean value of the rotor speed data at all times in the running period and the rated speed data of the motor rotor is used as the ratio of the motor speed at the first The degree of power loss during an operating period.

[0067] Preferably, in one embodiment of the present invention, according to the rotor speed data of the motor in the current cycle segment in each operating period, the specific method for obtaining the period lag between the motor shaft and the three-phase alternating current in each operating period is:

[0068] Obtain the current cycle duration of the motor through the motor internal circuit current monitoring module;

[0069] The three-phase alternating current is The duration of all complete motor current cycles within a running period is recorded as The current cycle segment in the operation period;

[0070] For For any current cycle segment in the operation time segments, the product of the average value of the rotor speed data at all times in the any current cycle segment and the current cycle length of the motor is recorded as the rotation distance of the motor shaft in the any current cycle segment; the ratio of the rotation distance of the motor shaft in the any current cycle segment to the circumference of the motor shaft is recorded as the rotation period proportion of the motor shaft in the any current cycle segment;

[0071] The first The ratio of the average of the motor shaft rotation period proportions in all current cycle segments in the running time period to the motor current cycle length is used as the motor in the first The periodic hysteresis between the shaft and the three-phase alternating current within an operating period;

[0072] The specific formula is:

[0073]

[0074] In the formula, Indicates that the motor is The periodic hysteresis between the shaft and the three-phase alternating current within an operating period; Indicates The average value of the rotation period proportion of the motor shaft in all current cycle segments in an operation period; Indicates the duration of the motor's current cycle.

[0075] It should be noted that The greater the lag deviation between the average of the rotation period proportions of the motor shaft in all current cycle segments in an operating period and the current cycle length of the motor, the higher the demagnetization probability of the permanent magnet motor.

[0076] Preferably, in one embodiment of the present invention, if the motor The greater the power loss during an operation period, the greater the The greater the period hysteresis between the shaft and the three-phase alternating current in each operating period, the greater the motor execution deviation; then according to the period hysteresis between the shaft and the three-phase alternating current and the power loss degree of the motor in each operating period, the specific method for obtaining the motor execution deviation degree of the motor in each operating period is:

[0077] Put the motor in The periodic hysteresis between the shaft and the three-phase alternating current in the first operating period is The product of the power loss degree in the operation period is taken as the power loss of the motor in the first The degree of motor execution deviation within a running period.

[0078] Preferably, in one embodiment of the present invention, if the motor execution deviation degree is greater in a certain operation period, and the magnetic field uniformity degree of the motor in the operation period is smaller, it means that the permanent magnet demagnetization performance is more significant; according to the motor execution deviation degree and the magnetic field uniformity degree of the motor in each operation period, the specific method for obtaining the demagnetization performance degree of the motor in each operation period is:

[0079]

[0080] In the formula, Indicates that the motor is The degree of demagnetization performance during a period of operation; Indicates that the motor is The degree of motor execution deviation within a running period; Indicates that the motor is The uniformity of the magnetic field during the operation period; represents the linear normalization function.

[0081] Preferably, in one embodiment of the present invention, according to the demagnetization performance degree of the motor in different operating periods, the specific method for obtaining the demagnetization state detection index of the motor permanent magnet is:

[0082] The last running period is recorded as the real-time running period; all running periods except the real-time running period are recorded as the historical running period;

[0083] For any historical operation period, the absolute value of the difference between the serial number of the any historical operation period and the real-time operation period is recorded as the time difference of the any historical operation period; the normalized value of the product of the reciprocal of the time difference of the any historical operation period and the demagnetization performance degree of the any historical operation period is recorded as the demagnetization performance degree prediction factor of the any historical operation period; the average value of the demagnetization performance degree prediction factors of all historical operation periods is taken as the demagnetization performance prediction value of the motor;

[0084] The ratio of the demagnetization performance degree of the motor in the real-time operation period to the predicted value of the demagnetization performance of the motor is used as the demagnetization state detection index of the permanent magnet of the motor.

[0085] At this point, the demagnetization state detection index of the motor permanent magnet is obtained.

[0086] Step S004: performing state detection on the permanent magnets of the motor based on the demagnetization state detection index.

[0087] Preferably, in one embodiment of the present invention, the specific method for detecting the state of the permanent magnet of the motor based on the demagnetization state detection index is:

[0088] Preset two threshold parameters and , wherein this embodiment is based on and This example is described as an example, and this embodiment is not specifically limited. and Depends on the specific implementation situation;

[0089] If the demagnetization state detection index of the motor permanent magnet is greater than or equal to the threshold parameter , the running state of the motor permanent magnet is recorded as good; if the demagnetization state detection index of the motor permanent magnet is less than the threshold parameter , the operating status of the motor permanent magnet is recorded as abnormal, and the motor needs to be inspected and replaced.

[0090] See also Figure 2 , which shows a characteristic relationship flow chart of a method for detecting a state of a permanent magnet in a permanent magnet synchronous motor;

[0091] At this point, this embodiment is completed.

[0092] Another embodiment of the present invention provides a permanent magnet state detection system for a permanent magnet synchronous motor, the system comprising a memory, a processor, and a computer program stored in the memory and running on the processor, and when the processor executes the computer program, the above method steps S001 to S004 are implemented.

[0093] Another embodiment of the present invention provides a permanent magnet state detection device for a permanent magnet synchronous motor, the device comprising:

[0094] A motor data acquisition module, a demagnetization state detection index acquisition module and a permanent magnet state detection module. The motor data acquisition module is used to obtain the rated speed data of the motor rotor, as well as the rotor vibration data and rotor speed data of the motor in several operating time periods. The demagnetization state detection index acquisition module implements the above method steps S001 to S004 by calling a computer program to obtain the demagnetization state detection index of the motor permanent magnet. The permanent magnet state detection performs state detection on the motor permanent magnet based on the demagnetization state detection index.

[0095] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting the state of a permanent magnet in a permanent magnet synchronous motor, characterized in that: The method comprises the following steps: Acquire the rated speed data of the motor rotor, as well as the rotor vibration data and rotor speed data of the motor in several operating periods; According to the change of the rotor vibration data of the motor in each operating period, the severity of the rotor vibration of the motor in each operating period is obtained; according to the difference between the rotor speed data of the motor in each operating period, the uniformity of the rotor speed of the motor in each operating period is obtained; according to the uniformity of the rotor speed and the severity of the rotor vibration of the motor in each operating period, the uniformity of the magnetic field of the motor in each operating period is obtained; According to the difference between the rotor speed data of the motor in each operating period and the rated speed data of the motor rotor, the power loss degree of the motor in each operating period is obtained; all current cycle periods in each operating period are obtained; according to the rotor speed data of the motor in the current cycle period in each operating period, the periodic hysteresis between the motor shaft and the three-phase alternating current in each operating period is obtained; according to the periodic hysteresis and power loss degree of the motor shaft and the three-phase alternating current in each operating period, the motor execution deviation degree of the motor in each operating period is obtained; according to the motor execution deviation degree and magnetic field uniformity of the motor in each operating period, the demagnetization performance degree of the motor in each operating period is obtained; according to the demagnetization performance degree of the motor in different operating periods, the demagnetization state detection index of the motor permanent magnet is obtained; The state of the permanent magnet of the motor is detected based on the demagnetization state detection index.

2. The method for detecting the state of a permanent magnet in a permanent magnet synchronous motor according to claim 1, characterized in that: The specific method of obtaining the vibration severity of the rotor of the motor in each operating period according to the change of the rotor vibration data of the motor in each operating period is as follows: For the motor In the running period, the running period is used as the horizontal coordinate and the rotor vibration data is used as the vertical coordinate to construct a two-dimensional coordinate system. The rotor vibration data in the running period is input into the two-dimensional coordinate system to obtain the motor in the first Rotor vibration curve within a running period; Put the motor in The normalized value of the product of the mean value of the rotor vibration data of all data points on the rotor vibration curve within the running period and the standard deviation of the rotor vibration data of all data points is used as the motor in the first The severity of rotor vibration during a certain operating period.

3. The method for detecting the state of a permanent magnet in a permanent magnet synchronous motor according to claim 1, characterized in that: The specific method of obtaining the uniformity of the rotor speed of the motor in each operating period according to the difference between the rotor speed data of the motor in each operating period is as follows: For The first At this moment, the motor The first The rotor speed data at the moment is consistent with the motor speed at the The absolute value of the difference between the mean values ​​of the rotor speed data at all times in the operation period is recorded as The speed difference value at the moment; the motor is The inverse of the mean of the speed difference values ​​at all times in the running period is taken as the speed difference of the motor at the The uniformity of the rotor speed within a certain operating period.

4. The method for detecting the state of a permanent magnet in a permanent magnet synchronous motor according to claim 1, characterized in that: The specific method of obtaining the uniformity of the magnetic field of the motor in each operating period according to the uniformity of the rotor speed and the intensity of the rotor vibration of the motor in each operating period is as follows: Put the motor in The inverse of the rotor vibration severity during the first operating period is related to the motor The normalized value of the product of the rotor speed uniformity within the running period is used as the motor The uniformity of the magnetic field during an operation period.

5. The method for detecting the state of a permanent magnet in a permanent magnet synchronous motor according to claim 1, characterized in that: The specific method of obtaining the power loss degree of the motor in each operating period according to the difference between the rotor speed data of the motor in each operating period and the rated speed data of the motor rotor is as follows: Put the motor in The ratio between the mean value of the rotor speed data at all times in the running period and the rated speed data of the motor rotor is used as the ratio of the motor speed at the first The degree of power loss during an operating period.

6. The method for detecting the state of a permanent magnet in a permanent magnet synchronous motor according to claim 1, characterized in that: The specific method of obtaining the period hysteresis between the motor shaft and the three-phase alternating current in each operating period according to the rotor speed data in the current cycle period of the motor in each operating period is as follows: For For any current cycle segment in the operation time segments, the product of the average value of the rotor speed data at all times in the any current cycle segment and the current cycle length of the motor is recorded as the rotation distance of the motor shaft in the any current cycle segment; the ratio of the rotation distance of the motor shaft in the any current cycle segment to the circumference of the motor shaft is recorded as the rotation period proportion of the motor shaft in the any current cycle segment; The first The ratio of the average of the motor shaft rotation period proportions in all current cycle segments in the running time period to the motor current cycle length is used as the motor in the first The periodic lag between the shaft and the three-phase alternating current within an operating period.

7. The method for detecting the state of a permanent magnet in a permanent magnet synchronous motor according to claim 1, characterized in that: The specific method of obtaining the motor execution deviation degree of the motor in each operating period according to the period hysteresis and power loss degree of the motor shaft and the three-phase alternating current in each operating period is as follows: Put the motor in The periodic hysteresis between the shaft and the three-phase alternating current in the first operating period is The product of the power loss degree in the operation period is taken as the power loss of the motor in the first The degree of motor execution deviation within a running period.

8. The method for detecting the state of a permanent magnet in a permanent magnet synchronous motor according to claim 1, characterized in that: The specific method of obtaining the demagnetization state detection index of the permanent magnet of the motor according to the demagnetization performance degree of the motor in different operating periods includes: The last running period is recorded as the real-time running period; all running periods except the real-time running period are recorded as the historical running period; For any historical operation period, the absolute value of the difference between the serial number of the any historical operation period and the real-time operation period is recorded as the time difference of the any historical operation period; the normalized value of the product of the reciprocal of the time difference of the any historical operation period and the demagnetization performance degree of the any historical operation period is recorded as the demagnetization performance degree prediction factor of the any historical operation period; the average value of the demagnetization performance degree prediction factors of all historical operation periods is taken as the demagnetization performance prediction value of the motor; The ratio of the demagnetization performance degree of the motor in the real-time operation period to the predicted value of the demagnetization performance of the motor is used as the demagnetization state detection index of the permanent magnet of the motor.

9. A permanent magnet state detection system for a permanent magnet synchronous motor, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of the method for detecting the state of a permanent magnet in a permanent magnet synchronous motor as described in any one of claims 1 to 8 are implemented.

10. A permanent magnet state detection device for a permanent magnet synchronous motor, the device comprising: A motor data acquisition module, a demagnetization state detection index acquisition module and a permanent magnet state detection module, wherein the motor data acquisition module is used to acquire the rated speed data of the motor rotor, as well as the rotor vibration data and the rotor speed data of the motor in several operating time periods, and the demagnetization state detection index acquisition module implements the steps of the permanent magnet state detection method for a permanent magnet synchronous motor as described in any one of claims 1 to 8 by calling a computer program to obtain the demagnetization state detection index of the motor permanent magnet, and the permanent magnet state detection performs state detection on the motor permanent magnet based on the demagnetization state detection index.

Images