Permanent magnet synchronous motor current state monitoring method based on digital twinning

Abstract

The invention relates to the technical field of permanent magnet synchronous motor current, and discloses a permanent magnet synchronous motor current state monitoring method based on digital twinning. According to the method, the phase current of the motor and the direct-current side current of the motor are collected, whether the phase current of the motor and the direct-current side current of the motor exceed overload values or not is judged, and under the condition that the overload values are not exceeded, a window epsilon is slid; the step length theta of the sliding window is used for calculating the collected phase current of the motor and the DC side current of the motor and the current fluctuation coefficient to obtain the current fluctuation coefficient of the permanent magnet synchronous motor, so that it is ensured that an abnormal value is difficult to equalize, and the calculation accuracy is ensured; and then comprehensive calculation is carried out based on the wiring loosening deflection angle and the leakage voltage of the permanent magnet synchronous motor wiring, an environment evaluation coefficient is finally obtained, the environment evaluation coefficient and the current fluctuation coefficient of the permanent magnet synchronous motor are combined to comprehensively obtain current state data, and the current condition of the permanent magnet synchronous motor can be visually expressed. And a data basis is provided for maintenance.

Description

Technical Field

[0001] The present invention relates to the field of permanent magnet synchronous motor current technology, and in particular to a permanent magnet synchronous motor current state monitoring method based on digital twin. Background Art

[0002] In recent years, electric drones have developed rapidly and are widely used in the fields of military, public security, agriculture, aerial photography, etc. At present, most drones are driven by permanent magnet synchronous motors. Permanent magnet synchronous motors have significant advantages such as simple structure, reliable operation, small size, small mass, low loss, high efficiency, and flexible and diverse shapes and sizes of motors. Their application areas are almost all over the fields of aerospace, national defense, industrial and agricultural production and daily life. However, after the motor has been running for several years, under the action of the temperature field, especially under the temperature change cycle caused by the start and stop of the unit, the gap will gradually increase along the longitudinal direction of the wire rod, thereby causing the performance of the generator itself to decline. When the operating voltage exceeds the starting discharge voltage of the insulation, partial discharge occurs. The thermal, mechanical and chemical effects caused by partial discharge gradually intensify, leading to fire or leakage; Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] In view of the shortcomings of the prior art, the present invention provides a permanent magnet synchronous motor current state monitoring method based on digital twin, which has the advantages of accurately evaluating the motor current state and solves the above-mentioned technical problems.

[0005] (II) Technical solution

[0006] To achieve the above object, the present invention provides the following technical solution: a method for monitoring the current state of a permanent magnet synchronous motor based on digital twin, comprising the following steps:

[0007] Step 1: Collect the phase current of the motor and the DC side current of the motor;

[0008] Step 2: Determine whether the phase current of the motor and the DC side current of the motor exceed the overload value. If so, determine whether overload protection is required. If overload protection is required, power off. If overload protection is not required, execute step 3.

[0009] Step 3: Calculate the current fluctuation coefficient according to the phase current of the motor and the DC side current of the motor collected in step 1 to obtain the current fluctuation coefficient of the permanent magnet synchronous motor;

[0010] Step 4: Collect the working environment data of the permanent magnet synchronous motor;

[0011] Step 5: Calculate the current state data based on the working environment data in step 4 and the current fluctuation coefficient of the permanent magnet synchronous motor.

[0012] As a preferred technical solution of the present invention, the specific expressions of the phase current of the motor and the DC side current of the motor collected in step 1 are as follows:

[0013]

[0014] Among them, DJDL represents the motor current dataset, They represent the motor A-phase current of the permanent magnet synchronous motor at the 1st sampling moment, ..., the motor A-phase current of the permanent magnet synchronous motor at the jth sampling moment, ..., the motor A-phase current of the permanent magnet synchronous motor at the Jth sampling moment, respectively. They represent the motor B-phase current of the permanent magnet synchronous motor at the 1st sampling moment, …, the motor B-phase current of the permanent magnet synchronous motor at the jth sampling moment, …, the motor B-phase current of the permanent magnet synchronous motor at the Jth sampling moment, respectively. They represent the motor C-phase current of the permanent magnet synchronous motor at the 1st sampling moment, ..., the motor C-phase current of the permanent magnet synchronous motor at the jth sampling moment, ..., the motor C-phase current of the permanent magnet synchronous motor at the Jth sampling moment, respectively. They respectively represent the motor DC side current of the permanent magnet synchronous motor after passing through the rectifier at the 1st sampling moment,…, the motor DC side current of the permanent magnet synchronous motor after passing through the rectifier at the jth sampling moment,…, and the motor DC side current of the permanent magnet synchronous motor after passing through the rectifier at the Jth sampling moment.

[0015] As a preferred technical solution of the present invention, the specific expression for determining whether overload protection is required in step 2 is as follows:

[0016]

[0017] Among them, ΔI α represents the comparison value of the ath current, represents the ath current in 1 to J sampling moments, a represents the index of the current type, and a=A, B, C, Z, and δ represents the overload safety threshold.

[0018] As a preferred technical solution of the present invention, the specific steps of calculating the current fluctuation coefficient in step 3 according to the phase current of the motor and the DC side current of the motor collected in step 1 are as follows:

[0019] Step 3.1: Establish a sliding window ∈ based on J sampling moments, and the step size of the sliding window is θ, and θ<∈;

[0020] Step 3.2: Substitute the phase current of the motor collected in step 1 into the current fluctuation coefficient calculation function with a sliding window ∈ and a step size θ of the sliding window to obtain the phase current fluctuation coefficient, and substitute the DC side current of the motor collected in step 1 into the current fluctuation coefficient calculation function to obtain the DC side current fluctuation coefficient;

[0021] Step 3.3: Based on the phase current fluctuation coefficient calculated in step 3.2, the DC side current fluctuation coefficient is calculated to obtain the permanent magnet synchronous motor current fluctuation coefficient.

[0022] As a preferred technical solution of the present invention, the specific expression of the current fluctuation coefficient calculation function is as follows:

[0023]

[0024] in, represents the maximum value of all values ​​calculated for each sliding window in the interval j∈[1,J], ∈ represents the sliding window, represents the a-type current at the J-th sampling moment, Indicates that a represents the index of the current type, and a=A, B, C, Z, represents the sum of all values ​​calculated in a sliding window, |*| represents the absolute value, DLBD a Indicates the current fluctuation coefficient of type a current.

[0025] As a preferred technical solution of the present invention, the specific expression of the permanent magnet synchronous motor current fluctuation coefficient obtained by comprehensively calculating the DC side current fluctuation coefficient calculated based on the phase current fluctuation coefficient calculated in step 3.2 is as follows:

[0026]

[0027] Among them, DLBD a represents the current fluctuation coefficient of type a current, ZHDLBD represents the current fluctuation coefficient of permanent magnet synchronous motor, ∑DLBD a It represents the sum of the current fluctuation coefficients of all types of current.

[0028] As a preferred technical solution of the present invention, the specific expression for collecting the working environment data of the permanent magnet synchronous motor in step 4 is as follows:

[0029]

[0030] Among them, JX1,…,JX m ,…,JX MU1,…,U2 respectively represent the loose connection angle of the first sampling point of the permanent magnet synchronous motor connection,…, the loose connection angle of the mth sampling point of the permanent magnet synchronous motor connection,…, the loose connection angle of the Mth sampling point of the permanent magnet synchronous motor connection, m ,…,U M They respectively represent the leakage voltage of the 1st sampling point of the permanent magnet synchronous motor connection, ..., the leakage voltage of the mth sampling point of the permanent magnet synchronous motor connection, ..., the leakage voltage of the Mth sampling point of the permanent magnet synchronous motor connection.

[0031] As a preferred technical solution of the present invention, the step 5 combines the working environment data in step 4 to calculate and combines the power supply fluctuation coefficient to obtain the current state data, including the following steps:

[0032] Step 5.1: Perform comprehensive calculation based on the loose connection angle and leakage voltage of the permanent magnet synchronous motor connection to finally obtain the environmental assessment coefficient;

[0033] Step 5.2: Combine the environmental assessment coefficient and the permanent magnet synchronous motor current fluctuation coefficient to obtain the current state data.

[0034] As a preferred technical solution of the present invention, in step 5.1, a comprehensive calculation is performed based on the loose connection angle and leakage voltage of the permanent magnet synchronous motor connection, and the specific expression of the environmental assessment coefficient is finally obtained as follows:

[0035] HJPG=max{sin(JX m )}+max{f(U m )}

[0036]

[0037] Among them, f(U m ) represents the leakage judgment function, sin(JX m ) represents the sine value of the loose connection angle, HJPG represents the environmental assessment coefficient, max{f(U m )} represents the maximum value among all leakage judgment functions, max{sin(JX m )} represents the maximum value of the sine value of all loose connection angles.

[0038] As a preferred technical solution of the present invention, the specific expression of the current state data obtained by combining the environmental assessment coefficient and the permanent magnet synchronous motor current fluctuation coefficient in step 5.2 is as follows:

[0039] DLZT=e HJPG+ZHDLBD -1

[0040] Among them, DLZT represents current state data, e represents natural constant, HJPG represents environmental assessment coefficient, and ZHDLBD represents permanent magnet synchronous motor current fluctuation coefficient.

[0041] Compared with the prior art, the present invention provides a permanent magnet synchronous motor current state monitoring method based on digital twin, which has the following beneficial effects:

[0042] The present invention collects the phase current and the DC side current of the motor and determines whether the phase current and the DC side current of the motor exceed the overload value. When the overload value is not exceeded, the current fluctuation coefficient of the collected phase current and the DC side current of the motor is calculated with a sliding window ∈ and a step size θ of the sliding window to obtain the current fluctuation coefficient of the permanent magnet synchronous motor, thereby ensuring that abnormal values ​​are difficult to be averaged and the accuracy of the calculation is ensured. Afterwards, a comprehensive calculation is performed based on the loose connection angle and the leakage voltage of the permanent magnet synchronous motor connection to finally obtain the environmental assessment coefficient. The current state data is obtained by combining the environmental assessment coefficient and the current fluctuation coefficient of the permanent magnet synchronous motor, thereby being able to intuitively describe the current situation of the permanent magnet synchronous motor and providing a data basis for maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0044] 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.

[0045] See also Figure 1 , a permanent magnet synchronous motor current state monitoring method based on digital twin, comprising the following steps:

[0046] Step 1: Collect the phase current of the motor and the DC side current of the motor;

[0047] The specific expressions of the motor phase current and the motor DC side current collected in step 1 are as follows:

[0048]

[0049] Among them, DJDL represents the motor current dataset, They represent the motor A-phase current of the permanent magnet synchronous motor at the 1st sampling moment, ..., the motor A-phase current of the permanent magnet synchronous motor at the jth sampling moment, ..., the motor A-phase current of the permanent magnet synchronous motor at the Jth sampling moment, respectively. They represent the motor B-phase current of the permanent magnet synchronous motor at the 1st sampling moment, …, the motor B-phase current of the permanent magnet synchronous motor at the jth sampling moment, …, the motor B-phase current of the permanent magnet synchronous motor at the Jth sampling moment, respectively. They represent the motor C-phase current of the permanent magnet synchronous motor at the 1st sampling moment, ..., the motor C-phase current of the permanent magnet synchronous motor at the jth sampling moment, ..., the motor C-phase current of the permanent magnet synchronous motor at the Jth sampling moment, respectively. They respectively represent the motor DC side current of the permanent magnet synchronous motor after passing through the rectifier at the 1st sampling moment,…, the motor DC side current of the permanent magnet synchronous motor after passing through the rectifier at the jth sampling moment,…, and the motor DC side current of the permanent magnet synchronous motor after passing through the rectifier at the Jth sampling moment.

[0050] Step 2: Determine whether the phase current of the motor and the DC side current of the motor exceed the overload value. If so, determine whether overload protection is required. If overload protection is required, power off. If overload protection is not required, execute step 3.

[0051] The specific expression for judging whether overload protection is required in step 2 is as follows:

[0052]

[0053] Among them, ΔI α represents the comparison value of the ath current, represents the ath current in 1 to J sampling moments, a represents the index of the current type, and a=A, B, C, Z, δ represents the overload safety threshold;

[0054] Step 3: Calculate the current fluctuation coefficient according to the phase current of the motor and the DC side current of the motor collected in step 1 to obtain the current fluctuation coefficient of the permanent magnet synchronous motor;

[0055] Step 3 The specific steps of calculating the current fluctuation coefficient based on the motor phase current and the DC side current of the motor collected in step 1 are as follows:

[0056] Step 3.1: Establish a sliding window ∈ based on J sampling moments, and the step size of the sliding window is θ, and θ<∈;

[0057] Step 3.2: Substitute the phase current of the motor collected in step 1 into the current fluctuation coefficient calculation function with a sliding window ∈ and a step size θ of the sliding window to obtain the phase current fluctuation coefficient. Substitute the DC side current of the motor collected in step 1 into the current fluctuation coefficient calculation function to obtain the DC side current fluctuation coefficient. The specific expression of the current fluctuation coefficient calculation function is as follows:

[0058]

[0059] in, represents the maximum value of all values ​​calculated for each sliding window in the interval j∈[1,J], ∈ represents the sliding window, represents the a-type current at the J-th sampling moment, Indicates that a represents the index of the current type, and a=A, B, C, Z, represents the sum of all values ​​calculated in a sliding window, |*| represents the absolute value, DLBD a Indicates the current fluctuation coefficient of type a current;

[0060] Step 3.3: Based on the phase current fluctuation coefficient calculated in step 3.2, the DC side current fluctuation coefficient is calculated to obtain the permanent magnet synchronous motor current fluctuation coefficient;

[0061] Step 3.3 Based on the phase current fluctuation coefficient calculated in step 3.2, the DC side current fluctuation coefficient is calculated and the specific expression of the permanent magnet synchronous motor current fluctuation coefficient is obtained by comprehensive calculation as follows:

[0062]

[0063] Among them, DLBD a represents the current fluctuation coefficient of type a current, ZHDLBD represents the current fluctuation coefficient of permanent magnet synchronous motor, ∑DLBD a It means summing the current fluctuation coefficients of all types of current;

[0064] Step 4: Collect the working environment data of the permanent magnet synchronous motor;

[0065] The specific expression for collecting the working environment data of the permanent magnet synchronous motor in step 4 is as follows:

[0066]

[0067] Among them, JX1,…,JX m ,…,JX M U1,…,U2 respectively represent the loose connection angle of the first sampling point of the permanent magnet synchronous motor connection,…, the loose connection angle of the mth sampling point of the permanent magnet synchronous motor connection,…, the loose connection angle of the Mth sampling point of the permanent magnet synchronous motor connection, m ,…,U M Respectively represent the leakage voltage of the 1st sampling point of the permanent magnet synchronous motor connection, ..., the leakage voltage of the mth sampling point of the permanent magnet synchronous motor connection, ..., the leakage voltage of the Mth sampling point of the permanent magnet synchronous motor connection;

[0068] Step 5: Calculate the current state data by combining the working environment data in step 4 and the current fluctuation coefficient of the permanent magnet synchronous motor. Step 5 includes the following steps:

[0069] Step 5.1: Perform comprehensive calculation based on the loose connection angle and leakage voltage of the permanent magnet synchronous motor connection to finally obtain the environmental assessment coefficient;

[0070] In step 5.1, the loose wiring angle and leakage voltage of the permanent magnet synchronous motor are comprehensively calculated, and the specific expression of the environmental assessment coefficient is finally obtained as follows:

[0071] HJPG=max{sin(JX m )}+max{f(U m )}

[0072]

[0073] Among them, f(U m ) represents the leakage judgment function, sin(JX m ) represents the sine value of the loose connection angle, HJPG represents the environmental assessment coefficient, max{F(U m )} represents the maximum value among all leakage judgment functions, max{sin(JX m )} represents the maximum value of the sine value of all loose connection angles;

[0074] Step 5.2: Combining the environmental assessment coefficient and the permanent magnet synchronous motor current fluctuation coefficient to obtain the current state data;

[0075] In step 5.2, the specific expression of the current state data obtained by combining the environmental assessment coefficient and the permanent magnet synchronous motor current fluctuation coefficient is as follows:

[0076] DLZT=e HJPG+ZHDLBD -1

[0077] Among them, DLZT represents current state data, e represents natural constant, HJPG represents environmental assessment coefficient, and ZHDLBD represents permanent magnet synchronous motor current fluctuation coefficient.

[0078] Example

[0079] The phase current of the motor and the DC side current of the motor collected in step 1 are shown in Table 1 below, with a sliding window ∈=5, a sliding step length θ=1, and a safety threshold δ=20;

[0080] Table 1 Experimental data of motor phase current and motor DC side current

[0081]

[0082] At this time, the calculation is based on the first five A phase currents. At this time DLBD A =max{0.2,0.22,0.24},DLBD B =max{0.2,0.22,0.24},DLBD C =max{0.56,0.58,0.6},DLBD C =max{0,0,0};

[0083]

[0084] Work environment dataset HJPG=max{sin(JX m )}+max{f(U m )}=sin(15°)+1=0.259+1=1.259

[0085] At this time, the current state data DLZT=e is obtained by combining the environmental assessment coefficient and the permanent magnet synchronous motor current fluctuation coefficient. HJPG+ZHDLBD -1=3.6136, so the accurate current status can be obtained. The lower the score, the higher the safety. When the value is greater than e-1, it means leakage and other conditions. When it is less than e-1, it means abnormal current and loose wiring.

[0086] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for monitoring the current state of a permanent magnet synchronous motor based on digital twins, characterized in that: The following steps are involved: Step 1: Collect the phase current of the motor and the DC side current of the motor; Step 2: Determine whether the phase current of the motor and the DC side current of the motor exceed the overload value. If so, determine whether overload protection is required. If overload protection is required, power off. If overload protection is not required, execute step 3. Step 3: Calculate the current fluctuation coefficient according to the phase current of the motor and the DC side current of the motor collected in step 1 to obtain the current fluctuation coefficient of the permanent magnet synchronous motor; Step 4: Collect the working environment data of the permanent magnet synchronous motor; Step 5: Calculate the current state data based on the working environment data in step 4 and the current fluctuation coefficient of the permanent magnet synchronous motor.

2. According to a method for monitoring the current state of a permanent magnet synchronous motor based on digital twinning according to claim 1, it is characterized in that: The specific expressions of the motor phase current and the motor DC side current collected in step 1 are as follows: Among them, DJDL represents the motor current dataset, They represent the motor A-phase current of the permanent magnet synchronous motor at the 1st sampling moment, ..., the motor A-phase current of the permanent magnet synchronous motor at the jth sampling moment, ..., the motor A-phase current of the permanent magnet synchronous motor at the Jth sampling moment, respectively. They represent the motor B-phase current of the permanent magnet synchronous motor at the 1st sampling moment, …, the motor B-phase current of the permanent magnet synchronous motor at the jth sampling moment, …, the motor B-phase current of the permanent magnet synchronous motor at the Jth sampling moment, respectively. They represent the motor C-phase current of the permanent magnet synchronous motor at the 1st sampling moment, ..., the motor C-phase current of the permanent magnet synchronous motor at the jth sampling moment, ..., the motor C-phase current of the permanent magnet synchronous motor at the Jth sampling moment, respectively. They respectively represent the motor DC side current of the permanent magnet synchronous motor after passing through the rectifier at the 1st sampling moment,…, the motor DC side current of the permanent magnet synchronous motor after passing through the rectifier at the jth sampling moment,…, and the motor DC side current of the permanent magnet synchronous motor after passing through the rectifier at the Jth sampling moment.

3. The method for monitoring the current state of a permanent magnet synchronous motor based on digital twin according to claim 2 is characterized in that: The specific expression for determining whether overload protection is required in step 2 is as follows: Among them, ΔI a represents the comparison value of the ath current, represents the ath current in 1 to J sampling moments, a represents the index of the current type, and a=A, B, C, Z, and δ represents the overload safety threshold.

4. The method for monitoring the current state of a permanent magnet synchronous motor based on digital twin according to claim 2 is characterized in that: The specific steps of calculating the current fluctuation coefficient in step 3 according to the phase current of the motor and the DC side current of the motor collected in step 1 are as follows: Step 3.1: Establish a sliding window ∈ based on J sampling moments, and the step size of the sliding window is θ, and θ<∈; Step 3.2: Substitute the phase current of the motor collected in step 1 into the current fluctuation coefficient calculation function with a sliding window ∈ and a step size θ of the sliding window to obtain the phase current fluctuation coefficient, and substitute the DC side current of the motor collected in step 1 into the current fluctuation coefficient calculation function to obtain the DC side current fluctuation coefficient; Step 3.3: Based on the phase current fluctuation coefficient calculated in step 3.2, the DC side current fluctuation coefficient is calculated to obtain the permanent magnet synchronous motor current fluctuation coefficient.

5. The method for monitoring the current state of a permanent magnet synchronous motor based on digital twin according to claim 4 is characterized in that: The specific expression of the current fluctuation coefficient calculation function is as follows: in, represents the maximum value of all values ​​calculated for each sliding window in the interval j∈[1,J], ∈ represents the sliding window, represents the a-type current at the J-th sampling moment, Indicates that a represents the index of the current type, and a=A, B, C, Z, represents the sum of all values ​​calculated in a sliding window, |*| represents the absolute value, DLBD a Indicates the current fluctuation coefficient of type a current.

6. The method for monitoring the current state of a permanent magnet synchronous motor based on digital twin according to claim 5 is characterized in that: The specific expression of the permanent magnet synchronous motor current fluctuation coefficient obtained by comprehensive calculation of the DC side current fluctuation coefficient calculated based on the phase current fluctuation coefficient calculated in step 3.2 is as follows: Among them, DLBD a represents the current fluctuation coefficient of type a current, ZHDLBD represents the current fluctuation coefficient of permanent magnet synchronous motor, ∑DLBD a It represents the sum of the current fluctuation coefficients of all types of current.

7. The method for monitoring the current state of a permanent magnet synchronous motor based on digital twin according to claim 4 is characterized in that: The specific expression for collecting the working environment data of the permanent magnet synchronous motor in step 4 is as follows: Among them, JX1,…,JX m ,…,JX M U1,…,U2 respectively represent the loose connection angle of the first sampling point of the permanent magnet synchronous motor connection,…, the loose connection angle of the mth sampling point of the permanent magnet synchronous motor connection,…, the loose connection angle of the Mth sampling point of the permanent magnet synchronous motor connection, m ,…,U M They respectively represent the leakage voltage of the 1st sampling point of the permanent magnet synchronous motor connection, ..., the leakage voltage of the mth sampling point of the permanent magnet synchronous motor connection, ..., the leakage voltage of the Mth sampling point of the permanent magnet synchronous motor connection.

8. The method for monitoring the current state of a permanent magnet synchronous motor based on digital twin according to claim 7 is characterized in that: The step 5 combines the working environment data in step 4 to calculate and combine the power supply fluctuation coefficient to obtain the current state data, including the following steps: Step 5.1: Perform comprehensive calculation based on the loose connection angle and leakage voltage of the permanent magnet synchronous motor connection to finally obtain the environmental assessment coefficient; Step 5.2: Combine the environmental assessment coefficient and the permanent magnet synchronous motor current fluctuation coefficient to obtain the current state data.

9. The method for monitoring the current state of a permanent magnet synchronous motor based on digital twin according to claim 8, characterized in that: In step 5.1, a comprehensive calculation is performed based on the loose connection angle and leakage voltage of the permanent magnet synchronous motor connection, and the specific expression of the environmental assessment coefficient is finally obtained as follows: HJPG=max{sin(JX m )}+max{f(U m )} Among them, f(U m ) represents the leakage judgment function, sin(JX m ) represents the sine value of the loose connection angle, hJPG represents the environmental assessment coefficient, max{f(U m )} represents the maximum value among all leakage judgment functions, max{sin(JX m )} represents the maximum value of the sine value of all loose connection angles.

10. The method for monitoring the current state of a permanent magnet synchronous motor based on digital twin according to claim 9, characterized in that: The specific expression of the current state data obtained by combining the environmental assessment coefficient and the permanent magnet synchronous motor current fluctuation coefficient in step 5.2 is as follows: DLZT=e HJPG+ZHDLBD -1 Among them, DLZT represents current state data, e represents natural constant, HJPG represents environmental assessment coefficient, and ZHDLBD represents permanent magnet synchronous motor current fluctuation coefficient.

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