A device and method for separating electromagnetic characteristics of a motor

Abstract

The application relates to a motor electromagnetic characteristic separation device and method, which comprises a sound insulation box, a test tool arranged in the sound insulation box and used for mounting a motor to be tested, a sound signal processing unit arranged outside the sound insulation box and used for acquiring noise sound pressure level data, a vibration signal processing unit arranged outside the sound insulation box and used for acquiring vibration signal processing results, and a data processing unit used for carrying out electromagnetic noise characteristic separation according to the noise sound pressure level data and / or electromagnetic vibration characteristic separation according to the vibration signal processing results. The application can avoid excessive energy leakage in the sound insulation box, signal loss and sound pressure data pollution caused by external additional excitation forces, meanwhile, after power-off of the motor, the motor can collect sufficient signal data; when the motor electromagnetic noise characteristic separation is carried out, the alignment slicing, data processing, matrix calculation and visualized result output of data before and after power-off can be automatically realized.

Description

Technical Field

[0001] This invention relates to the field of electric motors, and more particularly to a device and method for separating the electromagnetic characteristics of an electric motor. Background Technology

[0002] In existing technologies, when conducting noise tests on motors, the motor is usually placed inside a soundproof structure. After the motor is driven to rotate, a microphone and vibration sensor are used to detect the noise and vibration signals.

[0003] However, when implementing the above scheme, it is necessary to use a traction motor to drive the motor under test to rotate, which introduces unnecessary additional excitation force. The excitation force will generate new characteristic noise, so it is impossible to separate the characteristics of electromagnetic and mechanical noise of the motor under test itself. At the same time, it is necessary to increase the space for placing the traction motor stand, the integrated testing system, the power supply and drive control system. In addition, the traction motor needs to have an interface in the sound insulation structure to connect with the motor under test. Energy will leak through this interface, causing sound signal pollution.

[0004] Furthermore, precision machinery such as Stirling refrigerators utilizes miniature motors, which are often designed as separate units installed within the product. The motors and other components generate noise during operation. Testing the noise of the entire machine alone cannot pinpoint the noise from individual components, making it impossible to accurately identify and separate the mechanical and electromagnetic noise of the motor. Using a sudden power-off method for noise detection of these miniature motors is also problematic because the rotor's shutdown time after power loss is brief (typically less than 50ms for coreless motors, usually less than 10ms, characterized by the electromechanical time constant), resulting in insufficient signal data acquisition and inaccurate feature recognition. Summary of the Invention

[0005] The purpose of this invention is to provide a device and method for separating electromagnetic features of a motor. This device features a simple structure, low implementation cost, and small footprint, thereby avoiding excessive energy leakage within the soundproof enclosure that could cause signal loss, and eliminating sound pressure data pollution caused by external excitation forces. Furthermore, by improving the rotational inertia of the shaft, the motor can continue to operate for a certain period after power failure, ensuring sufficient data acquisition and high resolution. During the separation of electromagnetic noise enhancements in the motor, the device can automatically perform data alignment and slicing before and after power failure, data processing, matrix calculation, and visualization output, providing an effective and targeted testing and evaluation method for motor fault diagnosis and vibration reduction / noise optimization.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] On the one hand, an electromagnetic feature separation device for an electric motor is provided, comprising:

[0008] Soundproof box;

[0009] The test fixture, which is located inside the soundproof box, is used to install the motor to be tested;

[0010] An acoustic signal processing unit, located outside the soundproof enclosure, is used to process the noise signal generated when the motor under test is working in order to obtain noise sound pressure level data.

[0011] A vibration signal processing unit is located outside the soundproof box and is used to process the vibration signal generated when the motor under test is working in order to obtain the vibration signal processing result.

[0012] And a data processing unit, which is connected to the acoustic signal processing unit and / or the vibration signal processing unit, for performing electromagnetic noise feature separation based on the noise sound pressure level data, and / or performing electromagnetic vibration feature separation based on the vibration signal processing results.

[0013] Preferably, the test fixture includes:

[0014] A cylindrical body having an internal receiving space, and having a first open end and a second open end;

[0015] A rotating shaft has a rotating shaft body and a first rotating shaft extension end and a second rotating shaft extension end corresponding to the two ends of the rotating shaft body. The rotating shaft body is housed in the internal accommodating space of the cylindrical body. The first rotating shaft extension end extends toward the first open end, and the second rotating shaft extension end extends toward the second open end.

[0016] An end cap, which is connected to the cylindrical body, is used to close the second opening end and has an end cap receiving groove for accommodating the extension end of the second rotating shaft.

[0017] The rotor of the motor under test is connected to the outer peripheral surface of the first shaft extension end and extends axially into the first open end. The stator of the motor under test extends axially into the first open end and is connected to the cylindrical body.

[0018] Preferably, the moment of inertia of the rotating shaft satisfies the following condition:

[0019] J = (Tmax / 1000) * t / (ω * 1000)

[0020] Where J is the moment of inertia; Tmax is the stall torque of the motor under test; t is the electromechanical time constant of the motor under test; and ω is the no-load angular velocity of the motor under test.

[0021] Preferably, the test fixture further includes: an installation component connected to the cylindrical body, used to connect the entire test fixture to the frame.

[0022] Preferably, the test fixture further includes: a bearing mounting component, which is disposed within the internal accommodating space and connected to the inner wall of the cylindrical body, and the bearing mounting component has a bearing chamber;

[0023] The first bearing is installed in the bearing chamber and is sleeved on the outer circumferential surface of the extension end of the first shaft;

[0024] And a second bearing, which is installed in the end cover receiving groove and sleeved on the outer peripheral surface of the extension end of the second shaft.

[0025] Preferably, the test fixture further includes a spring, which is sleeved on the outer circumferential surface of the first rotating shaft extension end, and its two ends respectively abut against the first bearing and the shoulder of the first rotating shaft extension end.

[0026] Preferably, the inner and / or outer walls of the soundproof box are connected with soundproofing material.

[0027] On the other hand, a method for separating the electromagnetic features of an electric motor is also provided, which includes the following steps:

[0028] The motor to be tested is assembled onto the test fixture, and the frame connected to the test fixture is placed inside the soundproof box.

[0029] The motor control unit supplies power to the stator of the motor under test, and drives the rotor of the motor to start rotating through the magnetic field. At the same time, the sound signal acquisition unit and / or vibration signal acquisition unit are turned on to collect noise and vibration signals respectively.

[0030] After the speed of the motor under test accelerates from 0 to the maximum speed, the motor under test operates at the maximum speed for a predetermined time, the power to the motor under test is cut off, and the speed of the motor under test decelerates from the maximum speed to 0. The sound signal acquisition unit and / or vibration signal acquisition unit stop signal acquisition when the speed of the motor under test is 0.

[0031] The noise signal is processed to obtain noise sound pressure level data, and / or the vibration signal is processed to obtain vibration signal processing results;

[0032] Electromagnetic noise feature separation is performed based on the noise sound pressure level data, and / or electromagnetic vibration feature separation is performed based on the vibration signal processing results.

[0033] Preferably, the electromagnetic noise feature separation based on the noise sound pressure level data includes the following steps:

[0034] The noise sound pressure level data is imported and stored in matrix form.

[0035] Separate the sound pressure level data matrix A for the acceleration phase and the sound pressure level data matrix B for the deceleration phase from the noise sound pressure level data;

[0036] Both the acceleration phase sound pressure level data matrix A and the deceleration phase sound pressure level data matrix B are preprocessed to ensure that the dimensions and directions of the preprocessed acceleration phase sound pressure level data matrix A and deceleration phase sound pressure level data matrix B are consistent.

[0037] The sound pressure level data in the preprocessed acceleration phase sound pressure level data matrix A and deceleration phase sound pressure level data matrix B are respectively reverse calculated and restored to the acceleration phase sound pressure level data matrix A' and deceleration phase sound pressure level data matrix B'.

[0038] Subtract the sound pressure data matrix A' from the sound pressure data matrix B' from the sound pressure data matrix B' during the acceleration phase to obtain the sound pressure difference matrix C;

[0039] The values ​​less than 0 in the sound pressure difference matrix C are assigned very small positive numbers, and the sound pressure is converted into a sound pressure level. This sound pressure level data is the electromagnetic noise characteristic of the motor.

[0040] Preferably, the electromagnetic vibration feature separation based on the vibration signal processing results includes the following steps:

[0041] The vibration signal processing results are imported and stored in matrix form.

[0042] The vibration data matrix D for the acceleration phase and the vibration data matrix E for the deceleration phase are separated from the vibration signal processing results.

[0043] Both the acceleration phase vibration data matrix D and the deceleration phase vibration data matrix E are preprocessed to ensure that the dimensions and directions of the preprocessed acceleration phase vibration data matrix D and deceleration phase vibration data matrix E are consistent.

[0044] Subtract the vibration data matrix D of the acceleration phase after data preprocessing and the vibration data matrix E of the deceleration phase after data preprocessing to obtain the vibration data difference matrix F;

[0045] Assigning extremely small positive numbers to the values ​​less than 0 in the vibration data difference matrix F, the vibration signal processing result in the vibration data difference matrix F is the electromagnetic vibration characteristic of the motor.

[0046] In summary, the present invention has the following advantages compared with the prior art:

[0047] The motor electromagnetic noise feature separation device of the present invention has a simple structure, low implementation cost, and small footprint. The equipment installation and testing process is quicker and simpler. The motor under test, sound signal acquisition unit, and vibration signal acquisition unit inside the soundproof box can transmit signals to the motor control unit, sound signal processing unit, and vibration signal processing unit outside the soundproof box through wired / wireless connection. When connected by wire, only a small through hole for the cable to pass through is required on the soundproof box. There is no need to open a large hole structure, thereby avoiding excessive energy leakage inside the soundproof box and causing signal loss.

[0048] Meanwhile, there is no need to support the motor under test through the motor support equipment set outside the box or the large through holes opened on the soundproof box, thus eliminating the sound pressure data pollution caused by external excitation force; and by improving the rotational inertia of the shaft, the motor can still run for a certain period of time under inertia after the power is cut off, so as to ensure that there is enough signal acquisition data and the resolution is high enough.

[0049] When separating the electromagnetic noise and electromagnetic vibration characteristics of a motor, it can automatically perform data alignment and slicing before and after power failure (i.e., separation of data during acceleration and deceleration), data processing, matrix calculation, and visualization output, providing an effective and targeted testing and evaluation method for motor fault diagnosis and vibration and noise reduction optimization. Attached Figure Description

[0050] Figure 1 This is an overall structural diagram of the motor electromagnetic feature separation device in this invention.

[0051] Figure 2 This is an assembly diagram of the frame and testing fixture in this invention.

[0052] Figure 3 This is a cross-sectional view of the test fixture and the motor under test assembled in this invention.

[0053] Figure 4 This is a structural diagram of the test fixture and the motor under test assembled in this invention.

[0054] Figure 5 This is a flowchart of the steps in the method for separating the electromagnetic features of a motor in this invention.

[0055] Figure 6 This is a flowchart of the steps for obtaining the sound pressure difference matrix in this invention.

[0056] Figure 7 This is a waterfall plot of the electromagnetic noise characteristics of the motor generated from sound pressure level data in this invention.

[0057] Figure 8 This is a flowchart of the steps for obtaining the vibration data difference matrix in this invention.

[0058] Figure 9 This is a waterfall plot of the electromagnetic noise characteristics of the motor generated by vibration signal processing in this invention. Detailed Implementation

[0059] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0060] Example 1

[0061] The noise of an electric motor during operation typically includes electromagnetic noise and mechanical noise. Mechanical noise further includes bearing noise, friction noise, and wind noise. When a motor is suddenly de-energized while in operation, the phase wires of the motor are momentarily disconnected. The motor rotor gradually stops rotating according to the law of inertia until it comes to a complete stop. This process eliminates all electromagnetic excitation forces and reduces the natural frequency response of the motor stator. Furthermore, by analyzing the changes in the electromagnetic characteristics of the motor before and after the power outage, targeted fault location and optimization analysis can be performed on the motor.

[0062] like Figure 1-2 As shown, this embodiment provides a motor electromagnetic feature separation device, wherein the electromagnetic features include electromagnetic noise features and electromagnetic vibration features. Based on this, the motor electromagnetic feature separation device includes:

[0063] The soundproof box 1 has soundproofing material 110 connected to its inner and / or outer walls to prevent external sound signals from entering the soundproof box 1 and affecting the internal motor noise detection.

[0064] The frame 2 is placed inside the soundproof box 1;

[0065] Test fixture 3, which is connected to the frame 2 and is located inside the soundproof box 1, is used to install the motor 100 to be tested;

[0066] The motor control unit 4 is located outside the soundproof box 1 and is wired / wirelessly connected to the motor under test 100 inside the soundproof box 1. It is used to control the operation of the motor under test 100, including starting, stopping, and speed adjustment of the motor under test 100. In this embodiment, the motor control unit 4 is connected to the motor under test 100 through a motor cable 41 (e.g., a three-phase motor cable). One end of the motor cable 41 is connected to the motor control unit 4, and the other end extends into the soundproof box 1 through a wiring through-hole and is electrically connected to the motor under test 100 inside. In addition, the motor control unit 4 and the motor under test 100 can also interact with each other wirelessly, which can also realize the control of the operation of the motor under test 100.

[0067] The sound signal acquisition unit 5 is located inside the soundproof box 1 and is used to acquire the noise signal generated by the motor 100 under test when it is working. In this embodiment, the sound signal acquisition device 5 includes a microphone or different types of sound pressure sensors, and the distance between the sound signal acquisition unit 5 and the motor 100 under test meets the requirements of relevant standards such as GB / T10069.1-2006 "Methods and Limits for Noise Measurement of Rotating Electrical Machines - Part 1" and GB / T 17248.4-1998 "Noise Emitted by Acoustic Machines and Equipment, Sound Pressure Levels Emitted at Operating Positions and Other Designated Positions Determined by Sound Power Level".

[0068] An acoustic signal processing unit 6 is disposed outside the soundproof box 1 and is wired / wirelessly connected to the acoustic signal acquisition unit 5 inside the soundproof box 1. It is used to receive the noise signal and process the noise signal to obtain noise sound pressure level data. In this embodiment, the acoustic signal processing unit 6 is electrically connected to the acoustic signal acquisition device 5 inside the soundproof box 1 through an acoustic signal transmission cable 61. Alternatively, the acoustic signal processing unit 6 and the acoustic signal acquisition device 5 can also interact with each other wirelessly, as long as they can complete the acoustic signal transmission.

[0069] The vibration signal acquisition unit 7 is connected to the test fixture 3 and is used to acquire the vibration signal generated when the motor under test 100 is working. In this embodiment, the vibration signal acquisition unit 7 includes various vibration signal sensors that can realize vibration signal acquisition, and the vibration signal acquisition unit 7 is preferably attached to the axial end face of the test fixture 3.

[0070] A vibration signal processing unit 8 is disposed outside the soundproof box 1 and is wired / wirelessly connected to the vibration signal acquisition unit 7 inside the soundproof box 1. It receives the vibration signal and processes the vibration signal to obtain a vibration signal processing result, which includes one or more of the following: displacement, displacement velocity, and acceleration generated by the vibration. In this embodiment, the vibration signal processing unit 8 is electrically connected to the vibration signal acquisition unit 7 inside the soundproof box 1 via a vibration signal transmission cable 81. Alternatively, the vibration signal processing unit 8 and the vibration signal acquisition unit 7 can also interact wirelessly, as long as they can complete the vibration signal transmission and processing.

[0071] And a data processing unit 9, which is connected to the acoustic signal processing unit 6 and / or the vibration signal processing unit 8, for receiving noise sound pressure level data and / or vibration signal processing results, and performing electromagnetic noise feature separation based on the noise sound pressure level data, and / or performing electromagnetic vibration feature separation based on the vibration signal processing results.

[0072] Furthermore, such as Figure 3 As shown, the test fixture 3 includes:

[0073] The cylindrical body 31 has an internal receiving space 311 and a first opening end 312 and a second opening end 313; in this embodiment, the inner diameter of the first opening end 312 is smaller than the inner diameter of the second opening end 313.

[0074] The rotating shaft has a rotating shaft body 323 and a first rotating shaft extension end 321 and a second rotating shaft extension end 322 correspondingly connected to the two ends of the rotating shaft body 323. The rotating shaft body 321 is accommodated in the internal accommodating space 311 of the cylindrical body 31. The first rotating shaft extension end 321 extends toward the first opening end 312 and is located in the internal accommodating space 311, or extends to the outside of the first opening end 312. Similarly, the second rotating shaft extension end 322 extends toward the second opening end 313 and is located in the internal accommodating space 311, or extends to the outside of the second opening end 313. In this embodiment, the rotating shaft body 321, the first rotating shaft extension end 321 and the second rotating shaft extension end 322 can be integrally formed.

[0075] End cap 33, which is connected to the cylindrical body 31 by end cap fastener 332, etc., is used to close the second opening end 313, and has an end cap receiving groove 331 for accommodating the second rotating shaft extension end 322.

[0076] And the mounting component 34, which connects to the cylindrical body 31, is used to connect the test fixture 3 as a whole to the frame 2. For example, in this embodiment, the mounting component 34 can be a ring-shaped or hook-shaped structure. After the rope 341 passes through the ring-shaped or hook-shaped mounting component 34, it is connected to the frame 2, thereby realizing the hoisting of the test fixture 3 as a whole.

[0077] The rotor 101 of the motor under test 100 is connected to the outer peripheral surface of the first shaft extension end 321 and extends axially into the first opening end 312. At the same time, the rotor 101 is locked by the rotor locking member 103, so that the rotor 101 and the first shaft extension end 321 can rotate synchronously.

[0078] The stator 102 of the motor under test 100 extends axially into the first open end 312 and is connected to the cylindrical body 31 in the circumferential direction by stator fasteners 104 such as screws.

[0079] The rotor 101, stator 102, first open end 312, second open end 313, shaft body 321, first shaft extension end 321, second shaft extension end 322, cylindrical body 31, and end cap 33 are coaxially arranged.

[0080] Furthermore, the moment of inertia of the rotating shaft 32 satisfies the following condition:

[0081] J = (Tmax / 1000) * t / (ω * 1000)

[0082] Where J is the moment of inertia; Tmax is the stall torque of the motor under test; t is the electromechanical time constant of the motor under test; and ω is the no-load angular velocity of the motor under test.

[0083] When using the sudden power-off method to detect and separate the electromagnetic characteristics of micro motors, due to the small moment of inertia of micro motors, the motor will stop rotating within a very short time (a few milliseconds to tens of milliseconds) after the power is cut off, caused by the consumption of cogging torque and system damping. This results in the signal acquisition unit being unable to collect enough data. However, in this embodiment, the moment of inertia of the rotating shaft 32 is improved accordingly, so that the motor can still run for several seconds to tens of seconds under the action of inertia after the power is cut off, so as to ensure that there is enough signal acquisition data and the resolution is high enough.

[0084] The working process of the motor electromagnetic feature separation device in this embodiment is as follows:

[0085] The rotor 101 and stator 102 of the motor under test 100 are both assembled into the first open end 312 and locked and fixed respectively by the rotor locking member 103 and the stator fastener 104.

[0086] The test fixture 3, which is equipped with the motor to be tested 100, is connected to the frame 2 via rope 341, and then the frame 2 with the test fixture 3 is placed inside the soundproof box 1.

[0087] Under the control of the motor control unit 4, the motor power supply 10 supplies power to the stator 102 of the motor under test 100 to generate an alternating magnetic field, which in turn drives the rotor 101 to rotate, so that the motor under test 100 is in working state; at the same time, the sound signal acquisition unit 5 and / or vibration signal acquisition unit 7 are turned on to collect noise signals and / or vibration signals respectively.

[0088] After the motor under test 100 has been working for a predetermined time, the motor under test 100 is powered off until it completely stops rotating, at which point the sound signal acquisition unit 5 and / or the vibration signal acquisition unit 7 stop acquiring signals.

[0089] The acoustic signal processing unit 6 processes the noise signal to obtain noise sound pressure level data, and / or the vibration signal processing unit 8 processes the vibration signal to obtain vibration signal processing results.

[0090] The data processing unit 9 performs electromagnetic noise feature separation based on the noise sound pressure level data, and / or performs electromagnetic vibration feature separation based on the vibration signal processing results.

[0091] Therefore, the motor electromagnetic feature separation device in this embodiment has a simple structure, low implementation cost, and small footprint. The equipment installation and testing process is also quicker and simpler, making it particularly suitable for products such as Stirling refrigerators that use split-type motors. At the same time, the motor under test, sound signal acquisition unit, and vibration signal acquisition unit inside the soundproof box can transmit signals to the external motor control unit, sound signal processing unit, and vibration signal processing unit through wired / wireless connections. When using wired connections, only a small through hole needs to be opened on the soundproof box for the cable to pass through, without the need for a large perforated structure. This avoids excessive energy leakage inside the soundproof box, which could cause signal loss.

[0092] Furthermore, the motor under test is assembled onto the test fixture and is connected to the frame inside the soundproof box. This eliminates the need for motor support equipment outside the box or large through holes in the soundproof box to support the motor under test, thus preventing sound pressure data pollution caused by external vibration forces.

[0093] Example 2:

[0094] The only difference between this embodiment and Embodiment 1 is that the test fixture 3 further includes:

[0095] A bearing mounting component 11 is disposed within the internal accommodating space 311 and connected to the inner wall surface of the cylindrical body 31, and the bearing mounting component 11 has a bearing chamber 111; in this embodiment, the bearing mounting component 11 can be integrally formed with the cylindrical body 31, and the first rotating shaft extension end 321 passes through the bearing mounting component 11.

[0096] The first bearing 12 is installed in the bearing chamber 111 and is sleeved on the outer peripheral surface of the first shaft extension end 321;

[0097] The second bearing 13 is installed in the end cover receiving groove 331 and is sleeved on the outer peripheral surface of the second shaft extension end 322;

[0098] A spring 14 is sleeved on the outer circumferential surface of the first rotating shaft extension end 321, and its two ends respectively abut against the first bearing 12 and the shoulder 3211 of the first rotating shaft extension end 321.

[0099] In this embodiment, one or both of the first bearing 12 and the second bearing 13 are deep groove ball bearings, which can support both ends of the rotating shaft 21 to ensure rotational stability, while the springs buffer the axial impact on the rotating shaft.

[0100] Example 3:

[0101] This embodiment provides a method for separating the electromagnetic features of a motor as described in Embodiment 1 or 2, such as... Figure 5 As shown, it includes the following steps:

[0102] S1. Assemble the motor 100 to be tested onto the test fixture 3, and place the frame 2 connected to the test fixture 3 inside the soundproof box 1.

[0103] S2. Under the control of the motor control unit 4, the motor power supply 10 supplies power to the stator 102 of the motor under test 100 to generate an alternating magnetic field, which in turn drives the rotor 101 to start rotating. At the same time, the sound signal acquisition unit 5 and / or the vibration signal acquisition unit 7 are turned on to collect noise signals and vibration signals respectively.

[0104] S3. After the speed of the motor under test 100 accelerates from 0 to the maximum speed, the motor under test 100 operates at the maximum speed for a predetermined time. Then, the power to the motor under test 100 is cut off until the speed of the motor under test 100 decelerates from the maximum speed to 0. The sound signal acquisition unit 5 and / or the vibration signal acquisition unit 7 stop signal acquisition when the speed of the motor under test 100 is 0. The predetermined time can be determined according to factors such as the type of the motor under test 100 and the moment of inertia of the shaft. In this embodiment, it can be 1-20 seconds.

[0105] S4. The noise signal is processed by the sound signal processing unit 6 to obtain noise sound pressure level data, and / or the vibration signal is processed by the vibration signal processing unit 8 to obtain vibration signal processing results.

[0106] S5. The data processing unit 9 performs electromagnetic noise feature separation based on the noise sound pressure level data, and / or performs electromagnetic vibration feature separation based on the vibration signal processing results.

[0107] Among them, such as Figure 6 As shown, the data processing unit 9 performs electromagnetic noise feature separation based on the noise sound pressure level data, including the following steps:

[0108] S51. Import the noise sound pressure level data; in this embodiment, the noise sound pressure level data can be stored and displayed in matrix form, for example, with noise frequency and time as the x and y axes respectively, and sound pressure level data (unit dB) as the z axis, i.e. Figure 7 As shown, “A”, “B” and “uniform velocity point” are all sound pressure level data;

[0109] S52. Separate the sound pressure level data matrix A for the acceleration phase and the sound pressure level data matrix B for the deceleration phase from the noise sound pressure level data; wherein, the acceleration phase refers to the phase in which the speed of the motor under test 100 accelerates from 0 to the maximum speed, and the deceleration phase refers to the phase in which the speed of the motor under test 100 decelerates from the maximum speed to 0; the phase in which the motor under test 100 operates at the maximum speed for a predetermined time is the uniform speed phase, and there is no need to use the sound pressure level data in this uniform speed phase for electromagnetic noise separation;

[0110] S53. Perform data preprocessing on both the acceleration phase sound pressure level data matrix A and the deceleration phase sound pressure level data matrix B, so that the dimensions and directions of the preprocessed acceleration phase sound pressure level data matrix A and deceleration phase sound pressure level data matrix B are consistent.

[0111] Specifically, the preprocessing of the sound pressure level data matrix A during the acceleration phase includes:

[0112] A portion of the sound pressure level data is removed from the acceleration phase sound pressure level data matrix A to make the dimensions of the acceleration phase sound pressure level data matrix A and the deceleration phase sound pressure level data matrix B consistent. In this embodiment, the sound pressure level data removal can be done randomly or by removing one row every n rows, so that the dimensions of the acceleration phase sound pressure level data matrix A and the deceleration phase sound pressure level data matrix B are consistent (including the same number of rows and columns). For example, ... Figure 6 As shown, both are 5 rows × 8 columns matrices;

[0113] Data preprocessing for the sound pressure level data matrix B during the deceleration phase includes:

[0114] Rotate the sound pressure level data matrix B during the deceleration phase 180° clockwise;

[0115] The deceleration phase sound pressure level data matrix B, which has completed clockwise rotation, is flipped left and right once to make the pre-processed acceleration phase sound pressure level data matrix A and deceleration phase sound pressure level data matrix B have the same direction on the time axis.

[0116] S54. The sound pressure level data in the preprocessed acceleration phase sound pressure level data matrix A and deceleration phase sound pressure level data matrix B are respectively reverse-calculated back to the acceleration phase sound pressure level data matrix A' and deceleration phase sound pressure level data matrix B'. Since sound pressure level data cannot be used for matrix operations, the sound pressure level needs to be reverse-calculated back to sound pressure according to Lp = 20 * lg(p / p0), where Lp is the sound pressure level, P is the sound pressure, p0 is the reference sound pressure, and 2 × 10⁻⁶. -5 The power of (Pa);

[0117] S55. Subtract the sound pressure data matrix A' from the acceleration phase and the sound pressure data matrix B' from the deceleration phase to obtain the sound pressure difference matrix C.

[0118] S56. Assign extremely small positive numbers to the values ​​less than 0 in the sound pressure difference matrix C, and then convert the sound pressure into a sound pressure level according to Lp = 20*lg(p / p0). This sound pressure level data is the electromagnetic noise characteristic of the motor. Furthermore, the electromagnetic noise characteristic of the motor can be displayed visually, for example, in this embodiment, a waterfall plot of the motor electromagnetic noise characteristic (i.e.,...) can be used. Figure 7 The electromagnetic noise characteristics of the motor are displayed in the form of a "waterfall diagram of the separated motor electromagnetic noise characteristics".

[0119] Furthermore, the data processing unit 9 performs electromagnetic vibration feature separation based on the vibration signal processing results, including the following steps:

[0120] S51' Import a vibration signal processing result (i.e., one of displacement, displacement velocity, or acceleration); in this embodiment, the vibration signal processing result can be stored and displayed in matrix form, for example, with vibration frequency and time as the x and y axes, respectively, and acceleration (unit: m / s²) as the matrix. 2 ) is the z-axis, i.e. Figure 7 As shown, “D”, “E”, and “uniform velocity point” are all acceleration data;

[0121] S42' Separate the acceleration phase vibration data matrix D and the deceleration phase vibration data matrix E from the vibration signal processing results; wherein, the meanings of the acceleration phase, deceleration phase and constant speed phase are the same as in step S52, and will not be repeated here;

[0122] S43'. Perform data preprocessing on both the acceleration phase vibration data matrix D and the deceleration phase vibration data matrix E to ensure that the dimensions and directions of the preprocessed acceleration phase vibration data matrix D and deceleration phase vibration data matrix E are consistent.

[0123] Specifically, the data preprocessing for the vibration data matrix D during the acceleration phase includes:

[0124] To eliminate some vibration signal processing results from the acceleration phase vibration data matrix D, the dimensions of acceleration phase vibration data matrix D and deceleration phase vibration data matrix E are made consistent. In this embodiment, random elimination or elimination of one row every n rows can be used to eliminate the vibration signal processing results data, ensuring that the dimensions of the acceleration phase vibration data matrix D and deceleration phase vibration data matrix E are consistent (including the same number of rows and columns). For example... Figure 8 As shown, both are 5 rows × 8 columns matrices;

[0125] Data preprocessing for the vibration data matrix E during the deceleration phase includes:

[0126] Rotate the vibration data matrix E during the deceleration phase 180° clockwise.

[0127] The vibration data matrix E of the deceleration phase, which has completed clockwise rotation, is flipped left and right once so that the pre-processed vibration data matrix D of the acceleration phase and the vibration data matrix E of the deceleration phase are aligned on the time axis.

[0128] S44' Subtract the vibration data matrix D of the acceleration phase after data preprocessing and the vibration data matrix E of the deceleration phase after data preprocessing to obtain the vibration data difference matrix F;

[0129] S45' Assign extremely small positive numbers to the values ​​less than 0 in the vibration data difference matrix F. The vibration signal processing result in the vibration data difference matrix F is the electromagnetic vibration characteristic of the motor. Furthermore, the electromagnetic vibration characteristic of the motor can be displayed visually, for example, in this embodiment, a waterfall plot of the electromagnetic vibration characteristic of the motor (i.e.,...) can be used. Figure 9 The electromagnetic vibration characteristics of the motor are displayed in the form of a "waterfall diagram of the separated motor electromagnetic vibration characteristics".

[0130] In summary, the motor electromagnetic noise feature separation device of this invention has a simple structure, low implementation cost, and small footprint. The equipment installation and testing process is also quicker and simpler, making it particularly suitable for products using split-type motors, such as Stirling refrigerators. At the same time, the motor under test, sound signal acquisition unit, and vibration signal acquisition unit inside the soundproof box can transmit signals to the external motor control unit, sound signal processing unit, and vibration signal processing unit via wired / wireless connection. When using wired connection, only a small through hole needs to be made on the soundproof box for the cable to pass through, without the need for a large perforated structure, thereby avoiding excessive energy leakage inside the soundproof box and causing signal loss.

[0131] Furthermore, the motor under test is assembled onto the test fixture and is integrally connected to the frame inside the soundproof box. This eliminates the need for motor support equipment outside the box or large through holes in the soundproof box to support the motor under test, thus preventing sound pressure data pollution caused by external vibration forces. At the same time, through corresponding improvements to the rotational inertia of the shaft, this invention allows the motor to continue running for a certain period of time under inertia after power failure, ensuring sufficient signal acquisition data and high resolution.

[0132] When separating the electromagnetic noise and electromagnetic vibration characteristics of a motor, it can automatically perform data alignment and slicing before and after power failure (i.e., separation of data during acceleration and deceleration), data processing, matrix calculation, and visualization output, providing an effective and targeted testing and evaluation method for motor fault diagnosis and vibration and noise reduction optimization.

[0133] 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 spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for separating electromagnetic characteristics of an electric motor, characterized in that, include: Soundproof box; The test fixture, which is located inside the soundproof box, is used to install the motor to be tested; An acoustic signal processing unit, located outside the soundproof enclosure, is used to process the noise signal generated when the motor under test is working in order to obtain noise sound pressure level data. A vibration signal processing unit is located outside the soundproof box and is used to process the vibration signal generated when the motor under test is working in order to obtain the vibration signal processing result. And a data processing unit, which is connected to the acoustic signal processing unit and / or the vibration signal processing unit, for performing electromagnetic noise feature separation based on the noise sound pressure level data, and / or performing electromagnetic vibration feature separation based on the vibration signal processing results; The test fixture includes: A cylindrical body having an internal receiving space, and having a first open end and a second open end; A rotating shaft has a rotating shaft body and a first rotating shaft extension end and a second rotating shaft extension end corresponding to the two ends of the rotating shaft body. The rotating shaft body is housed in the internal accommodating space of the cylindrical body. The first rotating shaft extension end extends toward the first open end, and the second rotating shaft extension end extends toward the second open end. The moment of inertia of the shaft satisfies the following condition: J=(Tmax / 1000) t / (ω 1000); Where J is the moment of inertia; Tmax is the stall torque of the motor under test; t is the electromechanical time constant of the motor under test; and ω is the no-load angular velocity of the motor under test.

2. The motor electromagnetic feature separation device as described in claim 1, characterized in that, The testing fixture also includes: An end cap, which is connected to the cylindrical body, is used to close the second opening end and has an end cap receiving groove for accommodating the extension end of the second rotating shaft. The rotor of the motor under test is connected to the outer peripheral surface of the first shaft extension end and extends axially into the first open end. The stator of the motor under test extends axially into the first open end and is connected to the cylindrical body.

3. The motor electromagnetic feature separation device as described in claim 1, characterized in that, The testing fixture also includes: The mounting component connects to the cylindrical body and is used to connect the entire test fixture to the frame.

4. The motor electromagnetic feature separation device as described in claim 2, characterized in that, The testing fixture also includes: A bearing mounting component is disposed within the internal accommodating space and connected to the inner wall of the cylindrical body, and the bearing mounting component has a bearing chamber. The first bearing is installed in the bearing chamber and is sleeved on the outer circumferential surface of the extension end of the first shaft; And a second bearing, which is installed in the end cover receiving groove and sleeved on the outer peripheral surface of the extension end of the second shaft.

5. The motor electromagnetic feature separation device as described in claim 4, characterized in that, The testing fixture also includes: A spring is sleeved on the outer circumferential surface of the extension end of the first rotating shaft, and its two ends respectively abut against the first bearing and the shoulder of the extension end of the first rotating shaft.

6. The motor electromagnetic feature separation device as described in claim 1, characterized in that, The inner and / or outer walls of the soundproof box are connected with soundproofing material.

7. A method for separating electromagnetic features of a motor implemented by the motor electromagnetic feature separation device according to any one of claims 1-6, characterized in that, The steps include the following: The motor to be tested is assembled onto the test fixture, and the frame connected to the test fixture is placed inside the soundproof box. The motor control unit supplies power to the stator of the motor under test, and drives the rotor of the motor to start rotating through the magnetic field. At the same time, the sound signal acquisition unit and / or vibration signal acquisition unit are turned on to collect noise and vibration signals respectively. After the speed of the motor under test accelerates from 0 to the maximum speed, the motor under test operates at the maximum speed for a predetermined time, the power to the motor under test is cut off, and the speed of the motor under test decelerates from the maximum speed to 0. The sound signal acquisition unit and / or vibration signal acquisition unit stop signal acquisition when the speed of the motor under test is 0. The noise signal is processed to obtain noise sound pressure level data, and / or the vibration signal is processed to obtain vibration signal processing results; Electromagnetic noise feature separation is performed based on the noise sound pressure level data, and / or electromagnetic vibration feature separation is performed based on the vibration signal processing results.

8. The method for separating electromagnetic features of a motor as described in claim 7, characterized in that, Electromagnetic noise feature separation is performed based on the noise sound pressure level data, including the following steps: The noise sound pressure level data is imported and stored in matrix form. Separate the sound pressure level data matrix A for the acceleration phase and the sound pressure level data matrix B for the deceleration phase from the noise sound pressure level data; Both the acceleration phase sound pressure level data matrix A and the deceleration phase sound pressure level data matrix B are preprocessed to ensure that the dimensions and directions of the preprocessed acceleration phase sound pressure level data matrix A and deceleration phase sound pressure level data matrix B are consistent. The sound pressure level data in the preprocessed acceleration phase sound pressure level data matrix A and deceleration phase sound pressure level data matrix B are respectively reverse calculated and restored to the acceleration phase sound pressure level data matrix A' and deceleration phase sound pressure level data matrix B'. Subtract the sound pressure data matrix A' from the sound pressure data matrix B' from the sound pressure data matrix B' during the acceleration phase to obtain the sound pressure difference matrix C; The values ​​less than 0 in the sound pressure difference matrix C are assigned very small positive numbers, and the sound pressure is converted into a sound pressure level. This sound pressure level data is the electromagnetic noise characteristic of the motor.

9. The method for separating electromagnetic features of a motor as described in claim 7, characterized in that, Electromagnetic vibration feature separation is performed based on the vibration signal processing results, including the following steps: The vibration signal processing results are imported and stored in matrix form. The vibration data matrix D for the acceleration phase and the vibration data matrix E for the deceleration phase are separated from the vibration signal processing results. Both the acceleration phase vibration data matrix D and the deceleration phase vibration data matrix E are preprocessed to ensure that the dimensions and directions of the preprocessed acceleration phase vibration data matrix D and deceleration phase vibration data matrix E are consistent. Subtract the preprocessed vibration data matrix D from the preprocessed vibration data matrix E of the acceleration phase to obtain the vibration data difference matrix F. Assigning extremely small positive numbers to the values ​​less than 0 in the vibration data difference matrix F, the vibration signal processing result in the vibration data difference matrix F is the electromagnetic vibration characteristic of the motor.

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