A method for testing an AC magnetic modulation memory motor

Abstract

The present invention discloses a method for testing an AC magnetic modulation memory motor, comprising the following steps: S1, measuring the magnetization curve of the memory motor; S2, selecting n magnetization states of the memory motor according to the motor magnetization curve and actual needs, respectively denoted as MS i ; S3, according to the magnetization curve, it is preliminarily estimated that the magnetization state MS is guaranteed i The maximum d-axis demagnetization current that can be applied without demagnetization is denoted as I de _ i ; S4, get accurate demagnetization current I de_i ; S5, measure MS i MTPA trajectory under magnetization state. According to the characteristics of memory motor, the present invention provides the steps for perfecting the test of AC magnetic modulation memory motor, and provides guidance for the test of this type of motor; it can realize the measurement of memory motor magnetization curve, magnetization state selection, demagnetization characteristics under different magnetization states, and MTPA trajectory measurement, and provide support for the wide speed regulation operation of memory motor. It solves the problem of complex memory motor testing in the prior art.

Description

Technical Field

[0001] The invention belongs to the field of motor testing, and in particular relates to a method for testing an AC magnetic modulation type memory motor. Background Art

[0002] Compared with ordinary permanent magnet synchronous motors, memory machines (MM) have variable permanent magnet flux, which has attracted the attention and recognition of scholars at home and abroad. Usually, a direct axis (d-axis) pulse current is applied to change the magnetization state (MS) of the low coercive force permanent magnet inside, thereby changing the permanent magnet flux of the motor. Therefore, by adjusting the permanent magnet flux, wide speed regulation can be achieved, improving the overall efficiency of the motor operation.

[0003] However, the adjustable magnetization state of the memory motor brings a lot of trouble to the testing of its prototype. Problems such as demagnetization in the high magnetization state must be considered during the test. Therefore, a general method for testing AC magnetically adjustable memory motors is proposed, which specifically includes magnetization curve measurement, magnetization state selection, and maximum torque per ampere (MTPA) trajectory, which meets actual needs.

[0004] In view of the above problems, a testing method for AC magnetic modulation memory motor is designed. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide an AC magnetic modulation memory motor testing method, which solves the problem of complex memory motor testing in the prior art.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for testing an AC magnetic modulation memory motor comprises the following steps:

[0008] S1. Measure the magnetization curve of the memory motor;

[0009] S2. According to the motor magnetization curve and requirements, select n memory motor operation magnetization states, which are recorded as MS i , i=1,2,……,n;

[0010] S3. According to the magnetization curve, it is preliminarily estimated that under the magnetization state MS i The maximum d-axis demagnetization current that can be applied without demagnetization is denoted as I de _ i ;

[0011] S4, in magnetized state MS i, the rated q-axis current is applied, and the d-axis current is set to S3 to obtain the estimated demagnetization current I de _ i After running for a period of time, remove the dq axis current and measure the motor back EMF to determine whether the motor is demagnetized. If the motor is demagnetized, gradually reduce I de_i Repeat the measurement until the motor is not demagnetized and the accurate I de_i If the motor has not been demagnetized, gradually increase I de_i until the motor is about to be demagnetized; finally, the accurate demagnetization current I is obtained de_i ;

[0012] S5. When measuring MS i When the MTPA trajectory is in the magnetized state, the current vector I s The leading q-axis angle, that is, the current angle α, has a value range of 0 to α de , α de It is expressed as:

[0013]

[0014] Furthermore, S1 includes the following steps:

[0015] S1.1. Use the servo motor to drive the motor under test to rotate at a fixed speed n, and record the peak-to-peak value of the opposite potential V peak , calculate the current permanent magnet flux value:

[0016]

[0017] In the formula, ω e is the electrical angular velocity, p is the number of pole pairs;

[0018] S1.2, apply positive i d , increase its amplitude equally, and use the method of S1.1 to calculate the permanent magnet flux value. When i d Continue to increase, and stop when the permanent magnetic flux linkage does not change;

[0019] S1.3, then apply negative i d , increase its amplitude equally, and record the change of permanent magnetic flux linkage with i d The change curve of d Amplitude, when the permanent magnet flux decreases and approaches 0, stop measuring and get the demagnetization curve of the memory motor;

[0020] S1.4, then apply positive i d , increase its amplitude equally, and record the change of permanent magnetic flux linkage with i d The change curve of d Amplitude, when the permanent magnet flux increases and approaches 0, stop measuring and get the magnetization curve of the memory motor;

[0021] S1.5. By plotting the demagnetization curve and the magnetization curve together, we can get the magnetization curve.

[0022] Further, S2 includes the following steps:

[0023] S2.1, the permanent magnetic flux corresponding to the highest magnetization state of the magnetization curve is recorded as PMH, and the permanent magnetic flux corresponding to the lowest magnetization state is recorded as PML;

[0024] S2.2. According to the operation requirements, determine the number n of magnetization states to be selected. If the motor speed and torque operation range is expected to be wide, n≥5; if the magnetic modulation frequency is expected to be reduced, n≤3;

[0025] S2.3. Calculate each magnetization state MS i The corresponding permanent magnetic flux ψ PMi value:

[0026]

[0027] At the same time, the current values ​​required to switch between various magnetization states are recorded.

[0028] Furthermore, the demagnetization current I in S3 de_i , the specific explanation is as follows:

[0029] When the motor is in a high magnetization state, according to the demagnetization curve, when a small demagnetization current is applied, the permanent magnet flux linkage of the motor remains basically unchanged. However, when the amplitude of the applied demagnetization current gradually increases, the permanent magnet flux linkage begins to decrease. When the amplitude of the permanent magnet flux linkage is just reduced by Δψ PM When the current is recorded as the demagnetization current I in this magnetization state de_i , when the demagnetization current is greater than I de_i , it is considered that the motor is demagnetized.

[0030] Furthermore, the range of the MTPA current angle in S5 is limited to ensure that the amplitude of the d-axis component of the current vector is less than the demagnetization current I de_i , thus ensuring that the motor does not demagnetize.

[0031] Beneficial effects of the present invention:

[0032] 1. The AC magnetic modulation memory motor test method proposed in the present invention provides the steps for perfecting the test of the AC magnetic modulation memory motor according to the characteristics of the memory motor, and provides guidance for the test of this type of motor;

[0033] 2. The AC magnetic modulation memory motor test method proposed in the present invention can realize the measurement of the magnetization curve of the memory motor, the selection of the magnetization state, the demagnetization characteristics under different magnetization states, and the MTPA trajectory measurement, so as to provide support for the wide speed regulation operation of the memory motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0035] Figure 1 is an overall test flow chart of an embodiment of the present invention;

[0036] Figure 2 is a magnetization curve diagram of a memory motor according to an embodiment of the present invention;

[0037] Figure 3 is a magnetization curve diagram of a memory motor when three magnetization states are selected according to an embodiment of the present invention;

[0038] Figure 4 is a curve diagram of estimated value of demagnetization current in a high magnetization state according to an embodiment of the present invention;

[0039] Figure 5 Schematic diagram of MTPA current trajectory under demagnetization current limitation according to an embodiment of the present invention. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] like Figure 1 As shown, a method for testing an AC magnetic modulation memory motor specifically includes the following steps:

[0042] S1. Measure the magnetization curve of the memory motor;

[0043] S1.1. Use a servo motor to drive the motor under test to rotate at a fixed speed n (r / min) and record the peak-to-peak value of the opposite potential V peak (V), calculate the current permanent magnet flux value:

[0044]

[0045] In the formula, ω e is the electrical angular velocity, p is the number of pole pairs;

[0046] S1.2, apply positive i d , increase its amplitude equally, and use the method of S1.1 to calculate the permanent magnet flux value. When id Continue to increase, and stop when the change of permanent magnet flux is very small;

[0047] S1.3, then apply negative i d , increase its amplitude equally, and record the change of permanent magnetic flux linkage with i d The change curve of d Amplitude, when the permanent magnet flux decreases and approaches 0, stop measuring and get the demagnetization curve of the memory motor;

[0048] S1.4, then apply positive i d , increase its amplitude equally, and record the change of permanent magnetic flux linkage with i d The change curve of d Amplitude, when the permanent magnet flux increases and approaches 0, stop measuring and get the magnetization curve of the memory motor;

[0049] S1.5. By plotting the demagnetization curve and the magnetization curve together, we can get the magnetization curve.

[0050] S2. According to the motor magnetization curve and actual needs, select n memory motor operation magnetization states, respectively denoted as MS i , (i=1,2,...,n);

[0051] S2.1. The permanent magnetic flux corresponding to the highest magnetization state of the magnetization curve is recorded as PMH, and the permanent magnetic flux corresponding to the lowest magnetization state is recorded as PML, such as Figure 2 As shown;

[0052] S2.2. According to the operation requirements, determine the number n of magnetization states to be selected. If the motor speed and torque operation range is expected to be wide, a larger n (n≥5) can be selected; if the magnetic modulation frequency is expected to be reduced, a smaller n (n≤3) can be selected; Figure 3 As shown, the magnetization state selected when n = 3;

[0053] S2.3. Calculate each magnetization state MS i The corresponding permanent magnetic flux ψ PMi value:

[0054]

[0055] At the same time, the current values ​​required to switch between various magnetization states are recorded.

[0056] S3. According to the magnetization curve, it is preliminarily estimated that under the magnetization state MS i The maximum d-axis demagnetization current that can be applied without demagnetization is denoted as I de _ i ;

[0057] When the motor is in a high magnetization state, according to the demagnetization curve, when a small demagnetization current is applied, the permanent magnet flux linkage of the motor remains basically unchanged. However, when the amplitude of the applied demagnetization current gradually increases, the permanent magnet flux linkage begins to decrease. When the amplitude of the permanent magnet flux linkage is just reduced by Δψ PM When the current is recorded as the demagnetization current I in this magnetization state de_i , when the demagnetization current is greater than I de_i , it is believed that the motor is demagnetized. Figure 4 The demagnetization current I estimated from the magnetization curve at the highest magnetization state is given. de , corresponding to the position of the demagnetization point, at which the permanent magnetic flux is ψ PMH -Δψ PM ;

[0058] S4, in magnetized state MS i , the rated q-axis current is applied, and the d-axis current is set to S3 to obtain the estimated demagnetization current I de _ i After running for a period of time, remove the dq axis current and measure the motor back EMF to determine whether the motor is demagnetized. If the motor is demagnetized, gradually reduce I de_i Repeat the measurement until the motor is not demagnetized and the accurate I de_i If the motor has not been demagnetized, gradually increase I de_i until the motor is about to be demagnetized; finally, the accurate demagnetization current I is obtained de_i ;

[0059] The purpose of applying dq axis current at the same time is to determine the accurate value of demagnetization current under load. The value S3 preliminarily estimated using the magnetization curve has some deviation;

[0060] S5. When measuring MS i When the MTPA trajectory is in the magnetized state, the current vector I s The leading q-axis angle, that is, the current angle α, has a value range of 0 to α de , where α de It can be expressed as:

[0061]

[0062] The MTPA current angle value range is limited to ensure that the d-axis component of the current vector is smaller than the demagnetization current I de_i , thus ensuring that the motor does not demagnetize. Figure 5 As shown, in order to ensure that the MS i The state is not demagnetized, and the current angle is limited to 0 to α de During this time, the MTPA current trajectory is measured under this limitation.

[0063] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0064] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for testing an AC magnetic modulation memory motor, characterized in that: The specific steps include: S1. Measure the magnetization curve of the memory motor; S2. According to the motor magnetization curve and requirements, select n memory motor operation magnetization states, which are recorded as MS i , i=1,2,……,n; S3. According to the magnetization curve, it is preliminarily estimated that under the magnetization state MS i The maximum d-axis demagnetization current that can be applied without demagnetization is denoted as I de _ i ; S4, in magnetized state MS i , the rated q-axis current is applied, and the d-axis current is set to S3 to obtain the estimated demagnetization current I de _ i After running for a period of time, remove the dq axis current and measure the motor back EMF to determine whether the motor is demagnetized. If the motor is demagnetized, gradually reduce I de_i Repeat the measurement until the motor is not demagnetized and the accurate I de_i If the motor has not been demagnetized, gradually increase I de_i until the motor is about to be demagnetized; finally, the accurate demagnetization current I is obtained de_i ; S5. When measuring MS i When the MTPA trajectory is in the magnetized state, the current vector I s The leading q-axis angle, that is, the current angle α, has a value range of 0 to α de , α de It is expressed as:

2. The AC magnetic modulation memory motor testing method according to claim 1, characterized in that: S1 includes the following steps: S1.

1. Use the servo motor to drive the motor under test to rotate at a fixed speed n, and record the peak-to-peak value of the opposite potential V peak , calculate the current permanent magnet flux value: In the formula, ω e is the electrical angular velocity, p is the number of pole pairs; S1.2, apply positive value i d , increase its amplitude equally, and use the method of S1.1 to calculate the permanent magnet flux value. When i d Continue to increase, and stop when the permanent magnetic flux linkage does not change; S1.3, then apply negative value i d , increase its amplitude equally, and record the change of permanent magnetic flux linkage with i d The change curve of d Amplitude, when the permanent magnet flux decreases and approaches 0, stop measuring and get the demagnetization curve of the memory motor; S1.4, then apply positive i d , increase its amplitude equally, and record the change of permanent magnetic flux linkage with i d The change curve of d Amplitude, when the permanent magnet flux increases and approaches 0, stop measuring and get the magnetization curve of the memory motor; S1.

5. By plotting the demagnetization curve and the magnetization curve together, we can get the magnetization curve.

3. The AC magnetic modulation memory motor testing method according to claim 1, characterized in that: S2 includes the following steps: S2.1, the permanent magnetic flux corresponding to the highest magnetization state of the magnetization curve is recorded as PMH, and the permanent magnetic flux corresponding to the lowest magnetization state is recorded as PML; S2.

2. According to the operation requirements, determine the number n of magnetization states to be selected. If the motor speed and torque operation range is expected to be wide, n≥5; if the magnetic modulation frequency is expected to be reduced, n≤3; S2.

3. Calculate each magnetization state MS i The corresponding permanent magnetic flux ψ PMi value: At the same time, the current values ​​required to switch between various magnetization states are recorded.

4. The AC magnetic modulation memory motor testing method according to claim 1, characterized in that: Demagnetization current I in S3 de_i , the specific explanation is as follows: When the motor is in a high magnetization state, according to the demagnetization curve, when a small demagnetization current is applied, the permanent magnet flux linkage of the motor remains basically unchanged. However, when the amplitude of the applied demagnetization current gradually increases, the permanent magnet flux linkage begins to decrease. When the amplitude of the permanent magnet flux linkage is just reduced by Δψ PM When the current is recorded as the demagnetization current I in this magnetization state de_i , when the demagnetization current is greater than I de_i , it is considered that the motor is demagnetized.

5. The AC magnetic modulation memory motor testing method according to claim 1, characterized in that: The range of the MTPA current angle in S5 is limited to ensure that the d-axis component of the current vector is smaller than the demagnetization current I de_i , thus ensuring that the motor does not demagnetize.

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