Demagnetization detection method, device and electronic equipment for permanent magnet synchronous motor for elevator

Abstract

The present application relates to a demagnetization detection method, device and electronic equipment for a permanent magnet synchronous motor for an elevator, wherein the demagnetization detection method comprises: obtaining the actual torque data and actual angle data of the target elevator permanent magnet synchronous motor when rotating at no load through a torque sensor and an angle sensor respectively; determining the actual tooth slot torque angle spectrum according to the actual torque data and the actual angle data, and calculating the zero-centered standard deviation value of the actual tooth slot torque angle spectrum; judging whether the target elevator permanent magnet synchronous motor has irreversible demagnetization according to the zero-centered standard deviation value of the actual tooth slot torque angle spectrum and the target zero-centered standard deviation value. It can be completely implemented in a small machine room, and there is no need to disassemble the electrodes. It is a non-invasive detection method that can be used for demagnetization detection of elevator motors, solving the problem that the current demagnetization detection method of permanent magnet synchronous motors is not suitable for demagnetization detection of elevator motors.

Description

Technical Field

[0001] The present application relates to the field of elevator detection, and in particular to a demagnetization detection method, device and electronic equipment for a permanent magnet synchronous motor for an elevator. Background Art

[0002] At present, the methods used for demagnetization detection of permanent magnet synchronous motors mainly include direct measurement method and demagnetization detection method based on electrical signals. In the direct measurement method, the rotor of the motor to be tested is separated from the main machine, and the surface of the permanent magnet magnetic steel is directly measured by a Gauss meter (Tesla meter) to determine whether it is demagnetized. In the demagnetization detection method based on electrical signals, when the motor has a demagnetization fault, the magnetic field energy of the motor decreases. If a local demagnetization fault occurs in the motor, the asymmetry of the circuit will cause fault harmonics. If a uniform demagnetization fault occurs in the motor, the motor's various values ​​will change, affecting the steady-state operation of the motor. The motor's three-phase voltage, three-phase current, no-load back electromotive force, vibration, noise, temperature and other signals will change. Demagnetization detection is performed by monitoring various electrical signals. For example, the reverse drag method detects the no-load back electromotive force, and the three-phase current data of the motor is collected to determine whether demagnetization has occurred.

[0003] First, the direct measurement method requires the motor to be disassembled, which is a lot of work and is not conducive to the on-site inspection of the elevator by special equipment inspectors in the narrow motor room, thus reducing the efficiency of the inspection. The reverse drag method measures the change in the no-load back EMF amplitude, which requires the use of a motor of the same size as the motor under test for dragging. The elevator traction machine is large in size and the elevator room is small, making it difficult to implement.

[0004] Therefore, the current permanent magnet synchronous motor demagnetization detection method is not suitable for demagnetization detection of elevator motors. Summary of the invention

[0005] The present invention provides a demagnetization detection method, device and electronic equipment for a permanent magnet synchronous motor for an elevator to solve the problem that the current demagnetization detection method for a permanent magnet synchronous motor is not suitable for demagnetization detection of an elevator motor.

[0006] In a first aspect, the present invention provides a demagnetization detection method for a permanent magnet synchronous motor for an elevator, comprising:

[0007] The actual torque data and the actual angle data of the permanent magnet synchronous motor of the target elevator when rotating without load are obtained through the torque sensor and the angle sensor respectively;

[0008] Determine an actual cogging torque angle spectrum according to the actual torque data and the actual angle data, and calculate a zero-centered standard deviation value of the actual cogging torque angle spectrum;

[0009] According to the zero-centered standard deviation value of the actual cogging torque angle spectrum and the target zero-centered standard deviation value, it is determined whether the target elevator permanent magnet synchronous motor has irreversible demagnetization.

[0010] In a second aspect, the present invention provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor is configured to run the computer program to execute the demagnetization detection method for a permanent magnet synchronous motor for an elevator as described in the first aspect.

[0011] In a third aspect, the present invention provides a demagnetization detection device for a permanent magnet synchronous motor for an elevator, comprising a demagnetization detection device and the electronic device described in the second aspect;

[0012] The demagnetization detection device comprises:

[0013] A shaft adapter plate, used for being coaxially mounted on a traction sheave driven by a permanent magnet synchronous motor of a target elevator during demagnetization detection;

[0014] A hydraulic support rod, used for lifting the steel wire rope mounted on the traction wheel during demagnetization detection so that the steel wire rope does not contact the traction wheel;

[0015] An angle sensor is installed inside the belt shaft adapter plate and is used to measure the angle of the belt shaft adapter plate;

[0016] A torque sensor has one end coaxially connected to the belt shaft adapter disc and the other end coaxially connected to the driving device, and is used to measure the torque of the belt shaft adapter disc.

[0017] Compared with the related art, the present invention mainly determines whether the target elevator permanent magnet synchronous motor has irreversible demagnetization by the zero-centered standard deviation of the actual tooth slot torque angle spectrum of the target elevator permanent magnet synchronous motor. In this detection process, basically only a small torque sensor and angle sensor are needed to realize data collection, which can be completely realized in a small machine room, and there is no need to disassemble the motor. It is a non-invasive detection method that can be used for demagnetization detection of elevator motors, solving the problem that the current permanent magnet synchronous motor demagnetization detection method is not suitable for demagnetization detection of elevator motors.

[0018] Details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a flow chart of a demagnetization detection method for a permanent magnet synchronous motor for an elevator in an embodiment of the present invention;

[0020] Figure 2is a schematic diagram of the structure of a demagnetization detection device in some embodiments of the present invention;

[0021] Figure 3 is a schematic diagram of the interior of a shaft adapter disk in some embodiments of the present invention;

[0022] Figure 4 It is the cogging torque angle spectrum of the permanent magnet synchronous motor for elevators at different demagnetization (loss of magnetism) ratios;

[0023] Figure 5 is a flow chart of a demagnetization detection method for a permanent magnet synchronous motor for an elevator in some embodiments of the present invention;

[0024] Figure 6 It is the waveform of the cogging torque angle domain under healthy state;

[0025] Figure 7 is the frequency domain spectrum of the cogging torque under healthy conditions;

[0026] Figure 8 This is the waveform of the cogging torque angle domain under uniform demagnetization of 25%;

[0027] Fig. 9 This is the frequency domain spectrum of the cogging torque with uniform demagnetization of 25%;

[0028] Fig.10 This is the waveform of the cogging torque angle domain under 25% local demagnetization;

[0029] Fig.11 This is the frequency domain spectrum of the cogging torque when the local demagnetization is 25%;

[0030] Fig.12 This is the waveform of the cogging torque angle domain under 50% uniform demagnetization;

[0031] Fig.13 This is the frequency domain spectrum of the cogging torque with uniform demagnetization of 50%;

[0032] Fig.14 This is the waveform of the cogging torque angle domain under 50% local demagnetization;

[0033] Fig.15 It is the frequency domain spectrum of the cogging torque with 50% local demagnetization;

[0034] Fig.16 This is the finite element simulation analysis result of the motor structure. DETAILED DESCRIPTION

[0035] In order to more clearly understand the purpose, technical solutions and advantages of the present application, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments.

[0036] Unless otherwise defined, the technical terms or scientific terms involved in this application shall have the general meaning understood by people with general skills in the technical field to which this application belongs. The words "one", "a", "the", "these" and the like in this application do not indicate a quantitative limitation, and they may be singular or plural. The terms "include", "comprise", "have" and any variants thereof involved in this application are intended to cover non-exclusive inclusions; for example, a process, method and system, product or device comprising a series of steps or modules (units) is not limited to the listed steps or modules (units), but may include unlisted steps or modules (units), or may include other steps or modules (units) inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "multiple" involved in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there may be three relationships, for example, "A and / or B" may mean: A exists alone, A and B exist at the same time, and B exists alone. Generally, the character " / " indicates that the objects associated with each other are in an "or" relationship. The terms "first", "second", "third", etc. in this application are only used to distinguish similar objects and do not represent a specific ordering of the objects.

[0037] In an embodiment of the present invention, a demagnetization detection method for a permanent magnet synchronous motor for an elevator is provided. Figure 1 As shown, the process includes the following steps:

[0038] Step S110, obtaining actual torque data and actual angle data of the target elevator permanent magnet synchronous motor when rotating at no load through a torque sensor and an angle sensor respectively.

[0039] The target elevator permanent magnet synchronous motor is the elevator permanent magnet synchronous motor to be tested, and its actual torque data and actual angle data can be obtained through a demagnetization detection device containing a torque sensor and an angle sensor. The torque sensor and the angle sensor can be installed on the traction wheel driven by the target elevator permanent magnet synchronous motor. When the traction wheel rotates without load, different data can be obtained through the two sensors.

[0040] Reference Figure 2 and Figure 3In one embodiment, the demagnetization detection device includes: a belt shaft adapter plate 2, a hydraulic support rod and an angle sensor 7 and a torque sensor 4. The torque sensor 4 is connected to the belt shaft adapter plate 2 through a coupling 3, and the other end of the torque sensor 4 is connected to a driving device 5. The belt shaft adapter plate 2 is installed on the traction wheel, and the traction wheel is driven by the elevator permanent magnet synchronous traction machine 1. The torque sensor 4 can be supported by a telescopic sensor support stand 6.

[0041] The belt shaft adapter disc is used to be coaxially installed on the traction wheel driven by the permanent magnet synchronous motor of the target elevator during demagnetization detection; the hydraulic support rod is used to lift the wire rope installed on the traction wheel during demagnetization detection so that it does not contact the traction wheel; the angle sensor is installed inside the belt shaft adapter disc, and is used to measure the angle of the belt shaft adapter disc; one end of the torque sensor is coaxially connected to the belt shaft torque disc, and the other end is coaxially connected to the driving device, and is used to measure the torque of the belt shaft adapter disc.

[0042] During the detection process, on the one hand, the belt shaft adapter is coaxially installed on the traction wheel, and the two can be relatively fixed by bolts to achieve synchronous rotation of the two. Therefore, the angle of the traction wheel and the belt shaft adapter is the same, and the torque of the two is the same. The angle sensor can obtain the angle of the traction wheel by measuring the angle of the belt shaft adapter, and the torque sensor can obtain the torque of the traction wheel by measuring the torque of the belt shaft adapter. In order to achieve the no-load rotation of the traction wheel, the wire rope on the traction wheel can be lifted by the hydraulic support rod so that the wire rope does not contact the traction wheel. Of course, other methods or devices can also be used to make the wire rope and the traction wheel not contact. Among them, based on the working principle of the torque sensor, it can be known that the torque sensor has a measuring shaft, one end of the measuring shaft is connected to the object to be measured (the shaft on the belt shaft adapter can be connected through a coupling), and the other end of the measuring shaft is connected to the driving device. The driving transposition drives the object to be measured to rotate after measurement, and the torque sensor can measure the torque of the object to be measured when it rotates. Low-speed and high-torque electric drills, small motors, etc. can be used.

[0043] The above demagnetization detection device can be used to obtain the actual torque data and actual angle data of the target elevator permanent magnet synchronous motor when it rotates without load. Moreover, the device has a simple structure and a small size, and can be used in a small space. At the same time, it can be seen from the above description that the present invention does not require the elevator permanent magnet synchronous motor to be disassembled, and is a non-invasive detection method.

[0044] Step S120, determining the actual cogging torque angle spectrum according to the actual torque data and the actual angle data, and calculating the zero-centered standard deviation value of the actual cogging torque angle spectrum.

[0045] The cogging torque angle spectrum represents the relationship between torque data and angle data, and the actual cogging torque angle spectrum of the target elevator permanent magnet synchronous motor represents the actual torque of the target elevator permanent magnet synchronous motor at different angles. After determining the actual cogging torque angle spectrum, the zero-centered standard deviation value of the actual cogging torque angle spectrum can be calculated.

[0046] It should be noted that, in order to ensure the accuracy of subsequent data processing, the actual cogging torque angle spectrum should have at least 24 cogging torque cycles, so the torque sensor and the angle sensor need to continuously collect data so that the actual cogging torque angle spectrum has at least 24 cogging torque cycles. For example, the angle range corresponding to each cogging torque cycle can be calculated in advance, so as to determine the minimum angle that the traction wheel should rotate (the product of the angle range corresponding to each cogging torque cycle and the number of cycles).

[0047] In some of the embodiments, a conventional zero-centered standard deviation value calculation method may be used to calculate the zero-centered standard deviation value of the actual cogging torque angle spectrum.

[0048] In other embodiments, an optimized zero-centered standard deviation calculation method may be used to calculate the zero-centered standard deviation of the actual cogging torque angle spectrum.

[0049] Specifically, the optimized zero-centered standard deviation calculation method includes:

[0050] Step S121, calculating the centralization offset value of the actual cogging torque angle spectrum :

[0051]

[0052] Step S122, sampling the actual cogging torque angle spectrum to obtain the actual cogging torque at different angles, and performing zero-centering processing on the actual cogging torque at each angle:

[0053]

[0054] Step S123, calculating the zero-centered standard deviation value σ of the actual cogging torque angle spectrum:

[0055]

[0056] in, Represents the average of the peak values ​​of each cycle of the actual cogging torque angle spectrum, Represents the average of the valley values ​​of each cycle of the actual tooth slot torque angle spectrum, u i represents the actual cogging torque at the i-th angle after zero centering, xi represents the actual cogging torque at the i-th angle before zero centering, n Indicates the total number of angles sampled.

[0057] Generally speaking, the fluctuation center of the cogging torque angle spectrum is 0N·m. Since there may be errors in the measurement process, the fluctuation center of the cogging torque angle spectrum is not 0N·m. Therefore, it is necessary to perform a center shift on the actual cogging torque angle spectrum to eliminate the error so that the fluctuation center of the actual cogging torque angle spectrum is 0N·m. The above-mentioned optimized method for calculating the zero-centered standard deviation value is to first perform a center shift on the actual cogging torque angle spectrum (steps S121 and S122), and use the offset actual cogging torque angle to calculate the zero-centered standard deviation value (step S123).

[0058] The actual tooth slot torque angle spectrum is sampled, including:

[0059] Calculate the target sampling step size :

[0060]

[0061] in, Lm represents the least common multiple function, Z Indicates the number of stator slots of the target elevator permanent magnet synchronous motor, P Indicates the number of pole pairs of the target elevator permanent magnet synchronous motor.

[0062] The actual cogging torque angle spectrum is sampled according to the target sampling step size.

[0063] The above specifically introduces a sampling method of the actual cogging torque angle spectrum. The sampling step length is mainly determined according to the number of stator slots and the number of pole pairs of the target elevator permanent magnet synchronous motor.

[0064] Step S130, judging whether the target elevator permanent magnet synchronous motor has irreversible demagnetization according to the zero-centered standard deviation value of the actual cogging torque angle spectrum and the target zero-centered standard deviation value.

[0065] In some of the embodiments, the target zero-centered standard deviation value is a preset value. Usually, when the elevator permanent magnet synchronous motor is healthy and not demagnetized, the zero-centered standard deviation value of its cogging torque angle spectrum can be measured in advance or simulated. When the elevator permanent magnet synchronous motor is demagnetized, the zero-centered standard deviation value of its cogging torque angle spectrum will decay. Therefore, when the zero-centered standard deviation value of the cogging torque angle spectrum decays to a certain extent, it can be determined that the corresponding elevator permanent magnet synchronous motor has irreversible demagnetization. For example, 80% (or 85%, 75%, etc.) of the zero-centered standard deviation value of the cogging torque angle spectrum of the target elevator permanent magnet synchronous motor in a healthy state can be used as a preset value.

[0066] In other embodiments, the target zero-centered standard deviation value is a zero-centered standard deviation critical value for whether the target elevator permanent magnet synchronous motor has irreversible demagnetization. In this embodiment, the zero-centered standard deviation critical value of the cogging torque angle spectrum when the target elevator permanent magnet synchronous motor produces irreversible demagnetization can also be directly obtained in advance through simulation experiments.

[0067] As described above, the definition of the target zero-centered standard deviation value in different embodiments is described. There are also different embodiments for how to use the target zero-centered standard deviation value to perform demagnetization judgment.

[0068] In some embodiments, step S130 specifically includes:

[0069] When the zero-centered standard deviation value of the actual tooth slot torque angle spectrum is less than the target zero-centered standard deviation value, it is determined that the target elevator permanent magnet synchronous motor has irreversible demagnetization.

[0070] In this embodiment, the zero-centered standard deviation value of the actual cogging torque angle spectrum is directly compared with the target zero-centered standard deviation value.

[0071] In some other embodiments thereof, step S130 specifically includes:

[0072] A first ratio and a second ratio are calculated, the first ratio being the ratio of the zero-centered standard deviation value of the actual tooth slot torque angle spectrum to the zero-centered standard deviation factory value, and the second ratio being the ratio of the target zero-centered standard deviation value to the zero-centered standard deviation factory value. When the first ratio is less than the second ratio, it is determined that irreversible demagnetization exists in the target elevator permanent magnet synchronous motor.

[0073] In this embodiment, the zero-centered standard deviation factory value is the zero-centered standard deviation value of the cogging torque angle spectrum of the target elevator permanent magnet synchronous motor when it is healthy and not demagnetized. When the first ratio is less than the second ratio, it means that the zero-centered standard deviation value of the actual cogging torque angle spectrum is less than the target zero-centered standard deviation value.

[0074] It can be seen from the above description that the present invention mainly determines whether the target elevator permanent magnet synchronous motor has irreversible demagnetization by the zero-centered standard deviation value of the actual tooth slot torque angle spectrum of the target elevator permanent magnet synchronous motor. In this detection process, basically only a small torque sensor and angle sensor are needed to realize data collection, which can be completely realized in a small machine room, and there is no need to disassemble the motor. It is a non-invasive detection method that can be used for demagnetization detection of elevator motors, solving the problem that the current permanent magnet synchronous motor demagnetization detection method is not suitable for demagnetization detection of elevator motors.

[0075] In some of the embodiments, the demagnetization detection method for a permanent magnet synchronous motor for an elevator further includes:

[0076] Step S140, performing fast Fourier transform on the actual cogging torque angle spectrum to obtain the actual cogging torque frequency spectrum;

[0077] Step S150: When the main harmonic distortion rate of the actual cogging torque spectrum is less than the target threshold, it is determined that the target elevator permanent magnet synchronous motor is partially irreversibly demagnetized; otherwise, it is determined that the target elevator permanent magnet synchronous motor is uniformly irreversibly demagnetized.

[0078] In the above embodiment, it is not only possible to determine whether the target elevator permanent magnet synchronous motor is irreversibly demagnetized. It is also possible to further determine the type of irreversible demagnetization. First, the actual cogging torque angle spectrum is converted into the actual cogging torque spectrum by fast Fourier transform, and then the main harmonics of the actual cogging torque spectrum are determined and the distortion rate is calculated. Generally speaking, the main harmonic distortion rate of the actual cogging torque spectrum when the target elevator permanent magnet synchronous motor produces uniform demagnetization is basically the same as the main harmonic distortion rate of the actual cogging torque spectrum of the target elevator permanent magnet synchronous motor when it is healthy, while the main harmonic distortion rate of the actual cogging torque spectrum when the target elevator permanent magnet synchronous motor produces partial demagnetization is significantly reduced, so a target threshold can be set to distinguish the main harmonic distortion rate under different circumstances. First, the main harmonic distortion rate of the actual cogging torque spectrum of the target elevator permanent magnet synchronous motor when it is healthy (factory) can be obtained by pre-testing or simulating, and then the main harmonic distortion rate is appropriately reduced as the target threshold, such as by 10% or 15%.

[0079] In some of the embodiments, the demagnetization detection method for a permanent magnet synchronous motor for an elevator further includes:

[0080] Step S160, calculating the absolute average value of the actual cogging torque angle spectrum.

[0081] Step S170: When the target elevator permanent magnet synchronous motor is partially irreversibly demagnetized, the absolute average value of the actual cogging torque angle spectrum is substituted into the first function to obtain the demagnetization ratio of the target elevator permanent magnet synchronous motor.

[0082] Step S180: When the target elevator permanent magnet synchronous motor is uniformly irreversibly demagnetized, the absolute average value of the actual cogging torque angle spectrum is substituted into the second function to obtain the demagnetization ratio of the target elevator permanent magnet synchronous motor.

[0083] Among them, the first function is used to characterize the relationship between the demagnetization ratio of the target elevator permanent magnet synchronous motor under local irreversible demagnetization and the absolute average value of its cogging torque angle spectrum, and the second function is used to characterize the relationship between the demagnetization ratio of the target elevator permanent magnet synchronous motor under uniform irreversible demagnetization and the absolute average value of its cogging torque angle spectrum.

[0084] In this embodiment, on the basis of determining the demagnetization type of the target elevator permanent magnet synchronous motor, the demagnetization ratio of the target elevator permanent magnet synchronous motor can be further determined.

[0085] Specifically, when the elevator permanent magnet synchronous motor is demagnetized, the absolute average value of its cogging torque angle spectrum will decrease, and the decrease amplitude is positively correlated with the demagnetization ratio, but the specific relationship between the decrease amplitude and the demagnetization ratio is related to the demagnetization type. For any elevator permanent magnet synchronous motor, the functional relationship between the decrease amplitude of the cogging torque angle spectrum of the elevator permanent magnet synchronous motor under different demagnetization types (the difference between the healthy absolute average value and the actual absolute average value) and the demagnetization ratio can be obtained in advance through simulation. Since the healthy value of the cogging torque angle spectrum is known, the functional relationship can also be transformed into: the functional relationship between the actual absolute average value of the cogging torque angle spectrum of the elevator permanent magnet synchronous motor under different demagnetization types and the demagnetization ratio, which are the first function and the second function, respectively.

[0086] Therefore, after determining the demagnetization type of the target elevator permanent magnet synchronous motor, the absolute average value of the actual tooth slot torque angle spectrum can be substituted into the corresponding function, and the demagnetization ratio of the target elevator permanent magnet synchronous motor can be obtained.

[0087] An embodiment of the present invention further provides an electronic device, including a memory and a processor, wherein a computer program is stored in the memory, and the processor is configured to run the computer program to execute the demagnetization detection method for a permanent magnet synchronous motor for an elevator provided by the present invention.

[0088] In an embodiment of the present invention, a demagnetization detection device for a permanent magnet synchronous motor for an elevator is also provided, comprising a demagnetization detection device and an electronic device provided by the present invention;

[0089] Demagnetization testing equipment includes:

[0090] The shaft adapter plate is used for being coaxially mounted on a traction wheel driven by a permanent magnet synchronous motor of a target elevator during demagnetization detection.

[0091] The hydraulic support rod is used to lift the wire rope assembled on the traction sheave so that it does not contact the traction sheave during demagnetization detection.

[0092] An angle sensor is installed inside the shaft adapter and is used to measure the angle of the shaft adapter.

[0093] The torque sensor has one end coaxially connected to the shaft torque disk and the other end coaxially connected to the driving device, and is used to measure the torque of the shaft adapter disk.

[0094] As described above, at least one embodiment of each part of the demagnetization detection method for a permanent magnet synchronous motor for an elevator provided by the present invention has been described respectively. It should be noted that the various parts of the demagnetization detection method for a permanent magnet synchronous motor for an elevator can be combined using different embodiments to form different embodiments of the demagnetization detection method for a permanent magnet synchronous motor for an elevator. In addition, different descriptions can also be used for the same feature.

[0095] As a signal unique to permanent magnet motors, cogging torque is the alternating reluctance torque generated by the interaction between the permanent magnet poles and the slotted armature core when the winding is not energized. It is caused by the tangential component of the interaction force between the permanent magnet poles and the armature teeth. It is defined as the negative derivative of the magnetic field energy W of the permanent magnet motor with respect to the relative position angle a of the stator and rotor when the permanent magnet motor is not energized:

[0096]

[0097] When an irreversible demagnetization fault occurs in a permanent magnet synchronous motor, the magnetic flux density B of the permanent magnet motor magnet decreases, causing the motor magnetic field energy W to decrease. Since the cogging torque is only related to the motor magnetic field energy and the relative position angle of the stator and rotor, and the stator is fixed, the magnetic lines of force always tend to take the path of small magnetic resistance, always trying to pull the rotor to the position with the smallest magnetic resistance, so the motor rotor always tends to stop at a fixed position. Therefore, the torque is periodic and fluctuates around 0N·m. The amplitude of the fluctuation is related to the design parameters of each motor. The cogging torque is generally 1-3% of the rated torque. Since the permanent magnet synchronous motor for elevators is a low-speed, high-torque motor with a rated torque of usually above 400N·m, the corresponding cogging torque amplitude is also large, which can be measured by a torque sensor.

[0098] When the permanent magnet motor is demagnetized, the magnetic field energy of the motor will inevitably decrease, and the fluctuation amplitude of the cogging torque will inevitably decrease. At this time, by detecting the fluctuation coefficient of the cogging torque amplitude within one week of the permanent magnet motor, the magnetic field energy of the motor can be estimated, thereby determining whether a demagnetization fault has occurred. The figure below shows the fluctuation of the cogging torque under different demagnetization conditions.

[0099] Reference Figure 4 , which shows the fluctuation of the cogging torque under different demagnetization conditions.

[0100] Moreover, the cogging torque is detected when the motor is not powered, which can greatly reduce the interference of the most common circuit faults such as turn-to-turn short circuit on demagnetization detection and improve the accuracy of detection.

[0101] Reference Figure 5 In some embodiments, a demagnetization detection method for a permanent magnet synchronous motor for an elevator includes:

[0102] 1. Install the signal acquisition device to collect the angle spectrum of the cogging torque of the permanent magnet synchronous motor rotating at a constant speed without load.

[0103] The angle spectrum of the cogging torque of the permanent magnet synchronous motor refers to the value of the cogging torque received by the torque and angle sensor, which changes in real time with the angle when the permanent magnet synchronous motor rotates at a constant speed.

[0104] The fundamental period of the cogging torque is a formula for the cogging torque that is related to the number of stator slots Z and the number of motor pole pairs P. The fundamental period of the cogging torque is T=Lcm(Z, 2P), where Lcm is the lowest common multiple. The length of the fundamental period of the cogging torque within one cycle (corresponding to the mechanical angle) is h=360 / T ( / °).

[0105] The signal acquisition device includes:

[0106] The torque sensor and angle sensor are used to collect the angle spectrum of the tooth torque of the permanent magnet synchronous motor when it rotates at a constant speed. The angle sensor is built into the shaft adapter.

[0107] The hydraulic support rod is used to raise the position of the traction sheave wire rope to make it leave the traction sheave, so as to facilitate the detection of the running status of the motor when it is no-load.

[0108] With shaft adapter plate, bolted to the end face of the traction sheave.

[0109] Coupling, connecting the adapter plate shaft and the torque sensor.

[0110] Telescopic support stand to keep the torque sensor level with the shaft adapter plate axis.

[0111] The tester connects the driving device to the output shaft on the other side of the torque sensor and drags the slow motor to rotate at a constant speed (a low-speed, high-torque hand drill, a torque lever, or a low-speed, high-torque motor can all be used as the driving device).

[0112] First, the inspector cuts off the power to the motor and stops it from running; releases the pressure rod that fixes the wire rope on the traction machine, and installs the wire rope supported and fixed by hydraulic rods on both sides of the traction wheel (the wire rope does not need to be removed as long as it does not affect the rotation of the motor); removes the bolts on the end face of the motor traction wheel, installs the shaft adapter plate (with built-in angle sensor) to the end face of the traction wheel, and rigidly connects it with bolts; installs the torque sensor on the telescopic stand, and adjusts the stand height to be level with the adapter plate shaft; connects the adapter plate shaft to the torque sensor with a coupling; loosens the traction machine brake arm, and the inspector uses the drive device to drive the other end of the sensor to make the motor rotate slowly and evenly.

[0113] 2. Perform zero-centered data processing on the angle spectrum of the acquired cogging torque, select N fundamental periods of the cogging torque (N ≥ 24), and calculate the zero-centered standard deviation σ1 of the angle spectrum of the N cogging torque periods.

[0114] Zero centering means recording continuous samples in the angle domain x i The discrete data sequence obtained after sampling x i , i=1, 2, ..., n, realize the centering of the fluctuation axis with zero as the center. Because the original characteristic of the cogging torque is to fluctuate back and forth at the position of the center axis of 0N·m, the measurement error and other factors during data collection cause it to be not in the center position. The data needs to be processed. This can be done by eliminating outliers (the 3σ principle can be used) and centralizing the data. The centralization offset value for:

[0115]

[0116] in, is the mean value of the peak amplitude in each cogging torque cycle in the collected cogging torque angle spectrum, is the mean value of the amplitude of the trough in each cogging torque cycle in the collected cogging torque angle spectrum. ,for:

[0117]

[0118] Calculate the processed signal u i The standard deviation is the zero-centered standard deviation of the cogging torque:

[0119]

[0120] According to the original standard deviation formula, the standard deviation calculation formula is modified to adapt to the signal detection of the cogging torque. Its characteristic is that it reflects the fluctuation degree of a set of data about the cogging torque amplitude 0N·m. In particular, the periodic fluctuation amplitude of the cogging torque will gradually decrease with the deepening of the demagnetization of the permanent magnet. The demagnetization condition of the motor can be judged by observing the change of the zero-centered standard deviation σ after detection.

[0121] The specific steps for obtaining the angle spectrum of the cogging torque are as follows:

[0122] The collected torque value is processed by the torque sensor, and an angle sensor is installed at one end of the shaft to obtain the angle information during the rotation process.

[0123] Since the torque measured by the torque sensor also includes friction torque and hysteresis torque, the cogging torque of the tested motor is T c =T-(T F +T H ), where T c is the cogging torque; T is the measured torque of the device; T F is the friction torque; T H is the hysteresis torque.

[0124] The calculation method of friction torque and hysteresis torque is: , where m is the number of sampling points, is the sum of all measured torques. The cogging torque is: .

[0125] The collected signal is sent to the analog-to-digital converter (ADC), which converts the voltage signal collected by the sensor into a digital signal. The ADC converts the continuous voltage into a discrete digital value through sampling and quantization. A sampling and holding circuit is set during the collection process to store the collected torque signal and angle signal, and record the cogging torque detection value (cogging torque angle spectrum) corresponding to each angle position.

[0126] The specific sampling steps of the angle spectrum of the cogging torque are as follows:

[0127] To improve the detection accuracy, the sampling step size is set according to the number of stator slots of the tested motor. , in degrees (°), where Z is the number of stator slots of the tested motor, and P is the number of motor pole pairs. The larger the least common multiple, the smaller the sampling step interval. The cogging torque value corresponding to each point is determined by this, and the angle spectrum of the cogging torque rotating at a uniform speed is selected. Multiple cogging torque fundamental wave periods N are selected. To ensure the accuracy, N is as large as possible (N≥24), and it is processed into data.

[0128] 3. The ratio of the calculated zero-centered standard deviation σ1 to the zero-centered standard deviation σ0 of the motor when it leaves the factory is taken as the fault characteristic value k1.

[0129] 4. Detect the zeroing center standard deviation σ when the motor loses its magnetism S (σ Security threshold The ratio of the zero-centered standard deviation σ0 at the time of leaving the factory is used as the fault characteristic safety threshold k s (k Security threshold Abbreviation).

[0130] 5. When k s <k1<1, it is judged that the magnetic field energy of the permanent magnet of the motor rotor is still within the normal range. s When the permanent magnet synchronous motor is detected, it is judged that a demagnetization fault has occurred and the motor needs to be shut down for maintenance.

[0131] 6. Zero-centered cogging torque angle domain data u(i) Input to the fast Fourier transform (FFT) to perform angular domain Fourier transform to obtain its frequency domain spectrum, and set the basic frequency of the sampling signal to:

[0132]

[0133] To select the end angle of the fundamental cycle angle domain of the cogging torque, It is used to select the starting angle of the fundamental cycle angle domain of the cogging torque.

[0134] The harmonics of the frequency domain spectrum after observing the fast Fourier transform are H = f d i ( i =1,2,3…) is called the main harmonic. H major .

[0135] 7. Calculate the main harmonic distortion rate of the cogging torque frequency domain spectrum during this measurement:

[0136]

[0137] Let the main harmonic distortion rate of the motor in a healthy state be THD0; if 90%THD0>THD i , then the demagnetization of the motor at this time is partial demagnetization; if not, then the demagnetization of the motor at this time is uniform demagnetization.

[0138] Since the waveform of the motor cogging torque decreases according to the original waveform law when uniform demagnetization occurs, the waveform becomes distorted compared to the original waveform when local demagnetization occurs.

[0139] Reference Figure 6 and Figure 7 . Figure 6 is the waveform of the cogging torque angle domain under healthy conditions, Figure 7 This is the frequency domain spectrum of the cogging torque in a healthy state. At this time, the main harmonic distortion rate is THD0=79.61%.

[0140] Reference Figure 8 and Fig. 9 . Figure 8 This is the waveform of the cogging torque angle domain under uniform demagnetization of 25%. Fig. 9 The frequency domain spectrum of the cogging torque with uniform demagnetization of 25% is shown in the figure. The main harmonic distortion rate at this time is THD. i =79%.

[0141] Reference Fig.10 and Fig.11 . Fig.10This is the waveform of the cogging torque angle domain under 25% local demagnetization. Fig.11 This is the frequency domain spectrum of the cogging torque with a partial demagnetization of 25%. The main harmonic distortion rate at this time is THD i =52.03%.

[0142] Reference Fig.12 and Fig.13 . Fig.12 This is the waveform of the cogging torque angle domain under 50% uniform demagnetization. Fig.13 The frequency domain spectrum of the cogging torque with uniform demagnetization of 50% is shown in Figure 1. The main harmonic distortion rate at this time is THD. i =79.7%.

[0143] Reference Fig.14 and Fig.15 . Fig.14 This is the waveform of the cogging torque angle domain under 50% local demagnetization. Fig.15 This is the frequency domain spectrum of the cogging torque when the local demagnetization is 50%. The main harmonic distortion rate at this time is THD i =46.88%.

[0144] The main harmonic distortion rate of the cogging torque frequency domain spectrum refers to the distortion of the original cogging torque angle spectrum waveform caused by local demagnetization, that is, when a single permanent magnet is demagnetized. Slight local demagnetization has little effect on permanent magnet synchronous motors for elevators (multi-pole, generally more than 28 poles), but when a demagnetization fault occurs (serious local demagnetization occurs), the cogging torque angle spectrum waveform will be distorted, and its frequency domain spectrum will show that in addition to the main harmonics, secondary harmonics with other harmonic contents are generated. In the case of uniform demagnetization, the angle spectrum waveform of the cogging torque will decrease according to the original waveform law, and its frequency domain spectrum will show that the harmonic content of the frequency domain spectrum is basically consistent with that in the healthy state. At this time, the main harmonic distortion rate THD of the cogging torque frequency domain spectrum is calculated i It is possible to distinguish between uniform demagnetization and local demagnetization when a demagnetization fault occurs.

[0145] 8. Through simulation or simulation experiments, the absolute average value of the cogging torque angle spectrum of the tested motor under different degrees of uniform demagnetization and partial demagnetization is obtained:

[0146]

[0147] Perform least squares fitting to obtain the fitting function and , are the first function and the second function respectively. The function represents the relationship between the absolute average value of the cogging torque angle spectrum and the demagnetization ratio. Substituting the absolute average value of the cogging torque angle spectrum into the corresponding function, the demagnetization ratio of the elevator permanent magnet synchronous motor can be obtained.

[0148] Fitting the function by least squares The estimation of the degree of motor demagnetization refers to the fact that the absolute average value S of the cogging torque angle domain is inconsistent when the motor is uniformly demagnetized and partially demagnetized. Through simulation and simulation experiments, the decrease value of the motor when it is uniformly demagnetized and partially demagnetized can be obtained, and the least squares fitting can be performed. After distinguishing uniform demagnetization and partial demagnetization, the absolute average value S of the cogging torque angle spectrum at this time can be substituted into Determine the degree of demagnetization.

[0149] Demagnetization failure refers to the situation where the performance of the motor during normal operation is affected due to the demagnetization of the permanent magnet, reaching the level of irreversible demagnetization. Generally, it means that when the motor is working at the normal operating temperature, the residual magnetism Br of the motor permanent magnet is lower than the inflection point of its demagnetization curve, which is irreversible demagnetization and requires immediate shutdown for maintenance. The magnetic field energy of each motor when a demagnetization failure occurs is related to the performance of the permanent magnet brand used in each motor.

[0150] For example, refer to Fig.16 , perform finite element simulation analysis on the motor structure, set the healthy state, 25%, 50%, 75% uniform and local demagnetization faults. The following table shows the structural parameters of a permanent magnet synchronous motor for an elevator:

[0151] Table 1 Motor parameters

[0152]

[0153] At this time, the demagnetization is local demagnetization. Since the degree of local demagnetization decreases linearly, the least squares fitting is performed on the curve of local demagnetization. The fitting function is: ,in Substitute the absolute average value S of the tooth slot torque angle spectrum detected at this time into In the above example, the degree of demagnetization at this time can be uniquely determined.

[0154] Since the demagnetization fault phenomenon of the permanent magnet synchronous motor for elevators is a long-term process in daily use, in this embodiment, the host computer module is used to record and store the detection data according to the detection time, display the tooth slot torque angle spectrum, display the spectrum table after FFT conversion, display the zero-centered standard deviation, and display the fault threshold. Specifically, the fault characteristic values ​​detected multiple times for each device can be retained, such as: , ..., display the number of each device being tested, display the test date of each device along with the demagnetization fault characteristic value k 1，2，3 …changing waveform diagram, to implement long-term monitoring of the motor’s demagnetization status.

[0155] Based on the above embodiments, the present invention further provides a detection device for demagnetization of a permanent magnet synchronous motor for an elevator. In some embodiments, the detection device for demagnetization of a permanent magnet synchronous motor for an elevator comprises: a signal acquisition device, an analog-to-digital converter, a data processing module and a host computer.

[0156] The signal acquisition device includes:

[0157] The torque sensor and angle sensor are used to collect the angle spectrum of the tooth torque of the permanent magnet synchronous motor when it rotates at a constant speed. The angle sensor is built into the shaft adapter.

[0158] The hydraulic support rod is used to raise the position of the traction sheave wire rope to make it leave the traction sheave, so as to facilitate the detection of the running status of the motor when it is no-load.

[0159] With shaft adapter plate, bolted to the end face of the traction sheave.

[0160] Coupling, connecting the adapter plate shaft and the torque sensor.

[0161] Telescopic support stand to keep the torque sensor level with the shaft adapter plate axis.

[0162] The tester connects the driving device to the output shaft on the other side of the torque sensor and drags the slow motor to rotate at a constant speed (a low-speed, high-torque hand drill, a torque lever, or a low-speed, high-torque motor can all be used as the driving device).

[0163] Analog-to-digital converter: The collected signal is sent to the analog-to-digital converter (ADC), which converts the voltage signal collected by the sensor into a digital signal. The ADC converts the continuous voltage into a discrete digital value through sampling and quantization.

[0164] Data processing module: Set up a sampling and holding circuit during the acquisition process, store the acquired torque signal and angle signal, and record the cogging torque detection value corresponding to each angle position. Zero-center the acquired cogging torque angle spectrum, calculate the zero-center standard deviation σ1 and the demagnetization fault characteristic value k1, and when the fault characteristic value k1 is less than the fault characteristic safety threshold k s , then the motor has an irreversible demagnetization fault. The collected discrete signal data is input into the fast Fourier transform (FFT) for angle domain Fourier transform to obtain the frequency domain spectrum of the cogging torque. The main harmonic distortion rate THD of the frequency domain spectrum of the cogging torque is calculated based on the frequency domain data. i , to distinguish between uniform demagnetization and local demagnetization. This module is used to execute the demagnetization detection method of the permanent magnet synchronous motor for elevator provided by the present invention.

[0165] Host computer: used to record and store test data by test time, set a test number for each device, display the cogging torque angle spectrum waveform of each device at each test by date, display the frequency domain spectrum after fast Fourier transform (FFT), display the zero-centered standard deviation, and display the fault threshold. Display the test date of each device along with the demagnetization fault characteristic value k 1，2，3 …changing waveform. Detection result page: Output alarm signal when the fault threshold is lower than the fault threshold, and disassembly maintenance is required; according to the main harmonic distortion rate THD of the cogging torque frequency domain spectrum i , distinguish between uniform demagnetization and local demagnetization; if the fault threshold is not reached, the data will be stored according to the detection time; past data query function, all data are saved uniformly according to the detection number; data comparison function, can display the differences in multiple detection data results by time.

[0166] In summary, the demagnetization detection method and device for a permanent magnet synchronous motor for an elevator in the above embodiments have the following technical effects:

[0167] 1. The angle spectrum signal of the cogging torque is used to detect the demagnetization of the motor, which reduces the influence of motor circuit failure on demagnetization detection and improves the accuracy of demagnetization detection.

[0168] 2. The zero-centered standard deviation σ is used to quantify the fluctuation amplitude of the tooth slot torque angle spectrum. By comparing it with the zero-centered standard deviation during health and irreversible demagnetization, the fault characteristic threshold k is proposed. s , to qualitatively distinguish whether the motor has irreversible demagnetization.

[0169] 3. Use the main harmonic distortion rate converted from the angle spectrum of the cogging torque to the frequency domain spectrum. When the motor has irreversible demagnetization, the fault categories of local demagnetization and uniform demagnetization are distinguished based on the characteristics of uniform demagnetization and local demagnetization (the main harmonic distortion rate of uniform demagnetization is basically consistent with that of the healthy state, and the main harmonic distortion rate of local demagnetization is quite different from that of the healthy state).

[0170] 4. Use least squares fitting function To estimate the degree of motor demagnetization, when the motor demagnetization is clear, a least square fitting function is established according to the different demagnetization degrees of the motor. By substituting the measured value, the degree of motor demagnetization can be quantitatively estimated.

[0171] 5. The signal acquisition device enables special equipment inspectors to perform on-site non-invasive inspection of motor traction machines, and reduces the workload of disassembling the machine for inspection in traditional direct measurement methods, thereby improving the efficiency of inspection.

[0172] 6. Use the host computer detection system to classify the different types of elevator traction machines and record the detection data in categories, and save the detection data of each motor of each type separately. Not only the results of this detection are output, but also the waveform of the fault characteristic value of the elevator traction machine with the past detection date and the frequency domain distribution diagram after the angular domain Fourier transform are displayed to compare the data and realize long-term monitoring of the motor.

[0173] It should be understood that the specific embodiments described herein are only used to explain the application, rather than to limit it. Based on the embodiments provided in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of this application.

[0174] Obviously, the drawings are only some examples or embodiments of the present application. For ordinary technicians in the field, the present application can also be applied to other similar situations based on these drawings without creative work. In addition, it is understandable that although the work done in this development process may be complicated and lengthy, for ordinary technicians in the field, certain changes in design, manufacturing or production based on the technical content disclosed in this application are only conventional technical means and should not be regarded as insufficient content disclosed in this application.

Claims

1. A demagnetization detection method for a permanent magnet synchronous motor for an elevator, characterized in that: include: The actual torque data and the actual angle data of the permanent magnet synchronous motor of the target elevator when rotating without load are obtained through the torque sensor and the angle sensor respectively; determining an actual cogging torque angle spectrum according to the actual torque data and the actual angle data; Calculate the centering offset value of the actual cogging torque angle spectrum : The actual cogging torque angle spectrum is sampled to obtain the actual cogging torque at different angles, and the actual cogging torque at each angle is zero-centered: Calculate the zero-centered standard deviation of the actual cogging torque angle spectrum : in, Represents the average of the peak values ​​of each cycle of the actual cogging torque angle spectrum, Represents the average of the valley values ​​of each cycle of the actual tooth slot torque angle spectrum, u i represents the actual cogging torque at the i-th angle after zero centering, x i represents the actual cogging torque at the i-th angle before zero centering; When the zero-centered standard deviation value of the actual cogging torque angle spectrum is less than the target zero-centered standard deviation value, it is determined that the target elevator permanent magnet synchronous motor has irreversible demagnetization; or, a first ratio and a second ratio are calculated, the first ratio is the ratio of the zero-centered standard deviation value of the actual cogging torque angle spectrum to the factory value of the zero-centered standard deviation, and the second ratio is the ratio of the target zero-centered standard deviation value to the factory value of the zero-centered standard deviation. When the first ratio is less than the second ratio, it is determined that the target elevator permanent magnet synchronous motor has irreversible demagnetization.

2. The demagnetization detection method for a permanent magnet synchronous motor for an elevator according to claim 1, characterized in that: The target zero-centered standard deviation value is a preset value; Alternatively, the target zero-centered standard deviation value is a zero-centered standard deviation critical value of whether the target elevator permanent magnet synchronous motor has irreversible demagnetization.

3. The demagnetization detection method for a permanent magnet synchronous motor for an elevator according to claim 1, characterized in that: Sampling the actual cogging torque angle spectrum includes: Calculate the target sampling step size : in, Lm represents the least common multiple function, Z Indicates the number of stator slots of the target elevator permanent magnet synchronous motor, P Indicates the number of pole pairs of the target elevator permanent magnet synchronous motor; The actual cogging torque angle spectrum is sampled according to the target sampling step size.

4. The demagnetization detection method for a permanent magnet synchronous motor for an elevator according to claim 1, characterized in that: The actual cogging torque angle spectrum has at least 24 cogging torque periods.

5. The demagnetization detection method for a permanent magnet synchronous motor for an elevator according to claim 1, characterized in that: When the target elevator permanent magnet synchronous motor has irreversible demagnetization, the method further includes: Performing a fast Fourier transform on the actual cogging torque angle spectrum to obtain an actual cogging torque frequency spectrum; When the main harmonic distortion rate of the actual cogging torque spectrum is less than the target threshold, it is determined that the target elevator permanent magnet synchronous motor is partially irreversibly demagnetized; otherwise, it is determined that the target elevator permanent magnet synchronous motor is uniformly irreversibly demagnetized.

6. The demagnetization detection method for a permanent magnet synchronous motor for an elevator according to claim 5, characterized in that: When the target elevator permanent magnet synchronous motor has irreversible demagnetization, the method further includes: Calculating an absolute average value of the actual cogging torque angle spectrum; When the target elevator permanent magnet synchronous motor is partially irreversibly demagnetized, substituting the absolute average value of the actual cogging torque angle spectrum into the first function to obtain the demagnetization ratio of the target elevator permanent magnet synchronous motor; When the target elevator permanent magnet synchronous motor is uniformly irreversibly demagnetized, substituting the absolute average value of the actual cogging torque angle spectrum into the second function to obtain the demagnetization ratio of the target elevator permanent magnet synchronous motor; Among them, the first function is used to characterize the relationship between the demagnetization ratio of the target elevator permanent magnet synchronous motor under local irreversible demagnetization and the absolute average value of its cogging torque angle spectrum, and the second function is used to characterize the relationship between the demagnetization ratio of the target elevator permanent magnet synchronous motor under uniform irreversible demagnetization and the absolute average value of its cogging torque angle spectrum.

7. An electronic device comprising a memory and a processor, characterized in that: A computer program is stored in the memory, and the processor is configured to run the computer program to execute the demagnetization detection method for a permanent magnet synchronous motor for an elevator according to any one of claims 1 to 5.

8. A demagnetization detection device for a permanent magnet synchronous motor for an elevator, characterized in that: comprising a demagnetization detection device and an electronic device as claimed in claim 7; The demagnetization detection device comprises: A shaft adapter plate, used for being coaxially mounted on a traction sheave driven by a permanent magnet synchronous motor of a target elevator during demagnetization detection; A hydraulic support rod, used to lift the steel wire rope mounted on the traction wheel during demagnetization detection so that the steel wire rope does not contact the traction wheel; An angle sensor is installed inside the belt shaft adapter plate and is used to measure the angle of the belt shaft adapter plate; A torque sensor has one end coaxially connected to the belt shaft adapter disc and the other end coaxially connected to the driving device, and is used to measure the torque of the belt shaft adapter disc.

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