Device and method for testing demagnetization resistance of permanent magnet motor

Abstract

The invention relates to the technical field of motor performance evaluation, in particular to a device and method for testing the demagnetization resistance of a permanent magnet motor, and the device comprises a driving mechanism, a tested motor, a computer module, and a demagnetization module. The computer module can obtain the back electromotive force when the detected motor is in an open circuit state, and the demagnetization module can demagnetize a permanent magnet of the detected motor. According to the device, the problem that the actual rotating speed of the tested motor is not equal to the set rotating speed is solved in the mode that the driving mechanism drives the tested motor to rotate passively, the problem that the reverse electromotive force test is not accurate due to the inaccurate rotating speed is solved, obtained demagnetization data are more accurate, and the device is not simple in calculation simulation and is easy to popularize. In addition, the demagnetization rate can be truly detected and can be more accurately reflected.

Description

Technical Field

[0001] The present invention relates to the technical field of motor performance evaluation, and in particular to a device and method for testing the anti-demagnetization ability of a permanent magnet motor. Background Art

[0002] With the development of new energy vehicles, the advancement of industrial automation, and the country's emphasis on and call for energy conservation and emission reduction, the application of permanent magnet motors has become more and more extensive, gradually becoming a development trend in the motor industry.

[0003] The advantages of permanent magnet motors mainly come from the permanent magnetic field established by permanent magnets. However, the strength of the permanent magnetic field is affected by factors such as the performance of the permanent magnets themselves, the temperature of the permanent magnets during operation, overload current, harmonic shock, winding short circuit or phase loss. When the permanent magnets are irreversibly demagnetized due to the above factors, the permanent magnet motor will have problems such as reduced performance and reduced output power. In severe cases, abnormal heating, burning and fire may occur, and even endanger property and life safety. Therefore, it is necessary to test and evaluate the anti-demagnetization ability of permanent magnet motors to avoid the above situations.

[0004] Traditionally, the evaluation of anti-demagnetization capability is usually done through computer simulation. The calculated data is only a theoretical value and has a large error compared to the actual value. Summary of the invention

[0005] The purpose of the present invention is to solve one of the problems pointed out in the background technology, and to propose a permanent magnet motor anti-demagnetization ability testing device and method.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A permanent magnet motor anti-demagnetization ability testing device comprises a driving mechanism, a motor to be tested, a computer module and a demagnetization module. The power output end of the driving mechanism is transmission-connected to the rotating part of the motor to be tested. The computer module can obtain the reverse electromotive force when the motor to be tested is open-circuited. The demagnetization module can demagnetize the permanent magnet of the motor to be tested.

[0008] The testing equipment comprises a sealed door and an experimental chamber, wherein the sealed door and the experimental chamber can form an environmental simulation chamber, wherein the motor under test is located in the environmental simulation chamber, and wherein the environmental simulation chamber can at least change the ambient temperature of the motor under test during testing.

[0009] The demagnetization module includes a power supply, and the power supply can provide a direct current to the winding of the motor under test when the motor under test runs at a low speed.

[0010] The computer module can obtain current data supplied by the power supply to the winding of the motor under test.

[0011] The computer module can obtain resistance data of the motor under test.

[0012] The computer module includes a computer, a current acquisition unit, a voltage acquisition unit, and a resistance acquisition unit. The current acquisition unit can obtain the current data passed from the power supply to the winding of the motor under test and feed the current data back to the computer. The voltage acquisition unit can obtain the reverse electromotive force when the motor under test is open-circuited and feed the reverse electromotive force back to the computer. The resistance acquisition unit can obtain the resistance data of the motor under test and feed the resistance data back to the computer.

[0013] The environmental simulation chamber can simulate an environmental temperature of -50°C to +165°C;

[0014] And / or the driving mechanism and the motor under test are connected via a transmission mechanism;

[0015] And / or the experimental cabin is installed on a guide rail.

[0016] A method for testing the anti-demagnetization ability of a permanent magnet motor comprises the testing device described above, and the testing method comprises the following steps:

[0017] s1: Open the circuit of the motor under test, drive the motor under test to rotate to a first speed through the driving mechanism, obtain the voltage data of the motor under test through the voltage acquisition unit and feed it back to the computer, and record the voltage data at this time as the initial back electromotive force E0;

[0018] s2: The motor under test is driven to rotate to the second speed through the driving mechanism, and at the same time, a direct current is supplied to the winding of the motor under test through the power supply to perform the first demagnetization, and the current data I1 is recorded at the same time;

[0019] s3: The motor under test is driven to rotate to the first speed again by the driving mechanism, and the voltage data of the motor under test is obtained by the voltage acquisition unit and fed back to the computer, and the voltage data at this time is recorded as the real-time back electromotive force E1;

[0020] S4: gradually increase the current data, repeat steps S2 and S3 to obtain the current data I 1、2……n， At the same time, obtain the real-time back electromotive force E 1、2……n , calculate the demagnetization rate D by computer 1、2……m =(E0-E 1、2……n ) / E0; until the demagnetization rate Dm reaches the required value.

[0021] Before step s1, step a1 needs to be performed to set the temperature of the environmental simulation chamber. After waiting for a period of time, the resistance of the motor under test is obtained through the resistance acquisition unit and recorded as the initial resistance.

[0022] A2 needs to be performed between step s2 and step s3: after step s2 is completed, the power supply is disconnected, the driving mechanism is stopped, and the resistance of the motor under test is obtained through the resistance acquisition unit and recorded as the real-time resistance. When the real-time resistance is equal to the initial resistance, step s3 is performed;

[0023] s5: Generate the demagnetization rate curve of the motor under different current data at the set temperature of the environmental simulation chamber through computer.

[0024] The first rotation speed is greater than 100 rpm, and the second rotation speed is less than 1 rpm.

[0025] The present invention proposes a permanent magnet motor anti-demagnetization ability testing device and method, which have the beneficial effects of: the device eliminates the problem of the actual speed of the motor being tested being unequal to the set speed by driving the motor being tested to passively rotate through a driving mechanism, eliminates the problem of inaccurate reverse electromotive force test caused by inaccurate speed, and makes the obtained demagnetization data more accurate. In addition, the device is not a simple calculation simulation, but a real detection, and reflects the demagnetization rate more accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The three-dimensional structure of the present invention is shown in FIG. Figure 1 ;

[0027] Figure 2 The three-dimensional structure of the present invention is shown in FIG. Figure 2 ;

[0028] Figure 3 It is a schematic diagram of the electrical connection structure of the present invention;

[0029] Figure 4 The demagnetization rate curves of the motor under different currents tested by the present invention.

[0030] In the figure: current acquisition unit 1, voltage acquisition unit 2, resistance acquisition unit 3, computer 4, drive mechanism 5, test platform 6, speed change mechanism 7, mounting bracket 8, motor under test 9, sealed door 10, experimental cabin 11, guide rail 12. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0032] Reference Figure 1-Figure 4A permanent magnet motor anti-demagnetization ability testing device includes a driving mechanism 5, a motor under test 9, a computer module, and a demagnetization module. The power output end of the driving mechanism 5 is transmission-connected to the rotating part of the motor under test 9. The computer module can obtain the reverse electromotive force when the motor under test 9 is open-circuited. The demagnetization module can demagnetize the permanent magnet of the motor under test 9.

[0033] When the device is tested, the test motor 9 is opened, and the drive mechanism 5 drives the tested motor 9 to rotate passively. The reverse electromotive force of the tested motor 9 when the circuit is open is calculated by the computer module, and the demagnetization rate is determined by the reverse electromotive force data. The demagnetization and reverse electromotive force calculation are repeated, and the test is terminated when the demagnetization data finally reaches the required value.

[0034] The device eliminates the problem that the actual speed of the motor under test is not equal to the set speed by driving the motor under test to passively rotate through a driving mechanism, eliminates the problem of inaccurate reverse electromotive force test caused by inaccurate speed, and makes the demagnetization data obtained more accurate. In addition, the device is not a simple calculation simulation, but a real detection, which more accurately reflects the demagnetization rate.

[0035] The driving mechanism 5 of the device can use a driving motor, such as a servo motor, to drive the motor under test through a high-precision servo motor to reduce the problem of inaccurate back electromotive force testing caused by speed fluctuations of the motor under test, making the demagnetization data obtained more accurate.

[0036] refer to Figure 1-Figure 3 The test equipment includes a sealed door 10 and an experimental chamber 11. The sealed door 10 and the experimental chamber 11 can form an environmental simulation chamber. The motor 9 under test is located in the environmental simulation chamber. The environmental simulation chamber can at least change the ambient temperature of the motor 9 under test during the test.

[0037] The device simulates the operating environment temperature of the motor 9 under test through an environmental simulation chamber, and more accurately reflects the temperature of the actual operating environment. The present invention can simulate a working environment of -50°C to +165°C, so the real anti-demagnetization ability of the motor when running in various extreme environments can be tested.

[0038] As an embodiment, the demagnetization module includes a power supply, which can provide a DC current to the winding of the motor 9 under test when the motor 9 under test is running at a low speed. By applying a DC current to the winding of the motor under test through the power supply, the direction of the magnetic field generated at low speed is opposite to the direction of the magnetic field of the permanent magnet, thereby achieving a demagnetization effect.

[0039] The computer module can obtain the current data of the power supply supplied to the winding of the motor 9 under test, gradually increase the demagnetization current, record the current data each time, and determine the relationship between the current data and the demagnetization rate.

[0040] The computer module can obtain the resistance data of the motor under test 9. By testing the resistance of the motor under test, the temperature of the permanent magnet inside the motor under test is determined to eliminate the influence of the uncertainty of the actual temperature of the permanent magnet on the test result. For example, during demagnetization, the temperature of the motor under test will rise. If the back electromotive force is detected directly, the measured back electromotive force data will be inaccurate.

[0041] The computer module includes a computer, a current acquisition unit 1, a voltage acquisition unit 2, and a resistance acquisition unit 3. The current acquisition unit 1 can obtain the current data of the power supply entering the winding of the motor 9 under test, and feed the current data back to the computer. The voltage acquisition unit 2 can obtain the reverse electromotive force when the motor 9 under test is open-circuited, and feed the reverse electromotive force back to the computer. The resistance acquisition unit 3 can obtain the resistance data of the motor 9 under test, and feed the resistance data back to the computer.

[0042] The device determines the actual temperature of the motor 9 under test by detecting resistance, thereby avoiding the problem that the actual temperature of the motor 9 under test does not match the ambient temperature, improving the test accuracy, applying a demagnetization magnetic field through a power supply, and recording each current data and reverse electromotive force, so that the two form a demagnetization curve.

[0043] This device simulates various extreme temperature environments and truly measures the actual demagnetization rate of the permanent magnet motor under different demagnetization currents in actual use.

[0044] And / or the driving mechanism 5 and the motor 9 under test are connected to each other through a speed change mechanism 7, so as to control the speed of the motor 9 under test;

[0045] And / or the experimental cabin 11 is installed on the guide rail 12 to facilitate opening and closing of the environmental simulation cabin.

[0046] The driving mechanism 5 , the speed changing mechanism 7 , the mounting bracket 8 , and the motor to be tested 9 of the device are all mounted on the test platform 6 .

[0047] A method for testing the anti-demagnetization ability of a permanent magnet motor includes the above-mentioned testing device, and the testing method includes the following steps:

[0048] a1. Set the temperature of the environment simulation chamber, wait for a period of time, and obtain the resistance of the motor 9 under test through the resistance acquisition unit 3, which is recorded as the initial resistance;

[0049] s1: open the circuit of the motor 9 under test, and drive the motor 9 under test to rotate to a first speed through the driving mechanism 5. The first speed is greater than 100 rpm, for example, 200 rpm. The speed is determined according to the speed of the actual use environment of the motor, and is generally slightly greater than the speed of the actual use environment. The voltage data of the motor 9 under test is obtained through the voltage acquisition unit 2 and fed back to the computer 4. The voltage data at this time is recorded as the initial back electromotive force E0;

[0050] s2: The motor 9 under test is driven to rotate to the second speed through the driving mechanism 5, and at the same time, direct current is supplied to the winding of the motor 9 under test through the power supply to perform the first demagnetization, and the current data I1 is recorded at the same time; the power supply used in this method is a steady current source, which needs to be able to stably output the current required for the test under a load of 0 to 100Ω.

[0051] a2: After step s2 is completed, the power supply is disconnected, the driving mechanism 5 is stopped, and the resistance of the motor 9 under test is obtained through the resistance acquisition unit 3, which is recorded as the real-time resistance. When the real-time resistance is equal to the initial resistance, the subsequent steps are performed;

[0052] s3: The motor 9 under test is driven by the driving mechanism 5 to rotate again to the first speed, wherein the second speed is less than 1 rpm, for example, 0.1 rpm, and the voltage data of the motor 9 under test is obtained by the voltage acquisition unit 2 and fed back to the computer 4, and the voltage data at this time is recorded as the real-time back electromotive force E1;

[0053] S4: gradually increase the current data, repeat steps S2, A2, S3, and obtain the current data I 1、2……n， At the same time, obtain the real-time back electromotive force E 1、2……n , the demagnetization rate D is calculated by computer 4 1、2……m =(E0-E 1、2……n ) / E0; until the demagnetization rate Dm reaches the required value;

[0054] s5: Generate the demagnetization rate curve of the motor under different current data at the set temperature of the environmental simulation chamber through computer.

[0055] refer to Figure 3 , Figure 4 The present invention establishes a complete environmental simulation unit to simulate the actual temperature working environment, so as to test the anti-demagnetization ability of the motor under test in the actual use environment; the present invention can effectively determine whether the permanent magnet of the motor under test has recovered to the initial temperature, that is, by testing the resistance of the motor under test, to determine the temperature of the permanent magnet inside the motor under test, so as to eliminate the influence of the uncertainty of the actual temperature of the permanent magnet on the test result; the method uses a private service motor with high control accuracy as the driving motor, and its speed fluctuation is ≤0.01%, so as to ensure the accuracy of the test result and avoid the influence of the speed fluctuation on the test result, realize the anti-demagnetization ability of the permanent magnet of the motor under test at different temperatures and different demagnetization magnetic fields, and provide a complete and quantitative evaluation method.

[0056] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technical solution, conception, and design obtained by equivalent replacement or modification of the technical solution and inventive concept of the present invention by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A permanent magnet motor anti-demagnetization ability testing device, characterized in that: The invention comprises a driving mechanism (5), a motor to be tested (9), a computer module and a demagnetization module. The power output end of the driving mechanism (5) is drivingly connected to the rotating part of the motor to be tested (9). The computer module can obtain the reverse electromotive force when the motor to be tested (9) is open-circuited. The demagnetization module can demagnetize the permanent magnet of the motor to be tested (9).

2. A permanent magnet motor anti-demagnetization ability testing device according to claim 1, characterized in that: The test equipment comprises a sealed door (10) and a test chamber (11); the sealed door (10) and the test chamber (11) can form an environmental simulation chamber; the motor under test (9) is located in the environmental simulation chamber; and the environmental simulation chamber can at least change the ambient temperature of the motor under test (9) during testing.

3. A permanent magnet motor anti-demagnetization ability testing device according to claim 2, characterized in that: The demagnetization module comprises a power supply, and the power supply can provide a direct current to the winding of the motor (9) under test when the motor (9) under test is running at a low speed.

4. The permanent magnet motor anti-demagnetization ability testing device according to claim 3 is characterized in that: The computer module is capable of acquiring current data supplied by the power supply to the winding of the motor (9) under test; And / or the power supply is a constant current source.

5. A permanent magnet motor anti-demagnetization ability testing device according to claim 4, characterized in that: The computer module is capable of acquiring resistance data of the motor (9) under test.

6. A permanent magnet motor anti-demagnetization ability testing device according to claim 5, characterized in that: The computer module comprises a computer, a current acquisition unit (1), a voltage acquisition unit (2), and a resistance acquisition unit (3); the current acquisition unit (1) can acquire current data passed from a power supply to a winding of a motor (9) under test, and feed the current data back to the computer; the voltage acquisition unit (2) can acquire reverse electromotive force when the motor (9) under test is open-circuited, and feed the reverse electromotive force back to the computer; and the resistance acquisition unit (3) can acquire resistance data of the motor (9) under test, and feed the resistance data back to the computer.

7. A permanent magnet motor anti-demagnetization ability testing device according to any one of claims 2 to 6, characterized in that: The environmental simulation chamber can simulate an environmental temperature of -50°C to +165°C; and / or the driving mechanism (5) and the motor (9) to be tested are connected in transmission via a speed changing mechanism (7); And / or the experimental cabin (11) is installed on the guide rail (12).

8. A method for testing the anti-demagnetization ability of a permanent magnet motor, characterized in that: The test device according to any one of claims 1 to 7, wherein the test method comprises the following steps: s1: the motor under test (9) is opened, the motor under test (9) is driven to rotate to a first speed by the driving mechanism (5), the voltage data of the motor under test (9) is acquired by the voltage acquisition unit (2) and fed back to the computer (4), and the voltage data at this time is recorded as the initial back electromotive force E0; s2: driving the motor (9) under test to rotate to a second speed through the driving mechanism (5), and simultaneously supplying direct current to the winding of the motor (9) under test through the power supply to perform the first demagnetization, and simultaneously recording the current data I1; s3: driving the motor (9) under test to rotate to the first speed again through the driving mechanism (5), acquiring voltage data of the motor (9) under test through the voltage acquisition unit (2) and feeding it back to the computer (4), and recording the voltage data at this time as the real-time back electromotive force E1; S4: gradually increase the current data, repeat steps S2 and S3 to obtain the current data I 1、2……n， At the same time, obtain the real-time back electromotive force E 1、2……n , calculate the demagnetization rate D through computer (4) 1、2……m =(E0-E 1、2……n ) / E0; until the demagnetization rate Dm reaches the required value.

9. A permanent magnet motor anti-demagnetization ability testing device and method according to claim 8, characterized in that: Before step s1, step a1 needs to be performed, the temperature of the environment simulation chamber is set, and after waiting for a period of time, the resistance of the motor (9) under test is obtained through the resistance acquisition unit (3), which is recorded as the initial resistance; A2 needs to be performed between step s2 and step s3: after step s2 is completed, the power supply is disconnected, the operation of the driving mechanism (5) is stopped, and the resistance of the motor (9) under test is obtained through the resistance acquisition unit (3), which is recorded as the real-time resistance. When the real-time resistance is equal to the initial resistance, step s3 is performed; s5: Generate the demagnetization rate curve of the motor under different current data at the set temperature of the environmental simulation chamber through computer.

10. A permanent magnet motor anti-demagnetization ability testing device and method according to claim 9, characterized in that: The first rotation speed is greater than 100 rpm, and the second rotation speed is less than 1 rpm.

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