Method and system for measuring alternating current loss of motor winding

Abstract

The invention discloses a motor winding alternating current loss measurement method and system, and relates to the technical field of motor winding loss measurement. The invention aims to solve the problem that the winding loss is difficult to simply and effectively measure under the condition that the hardware and software cost is not increased. A tested motor is simplified and equivalent to a stator winding and a stator iron core; and calculating the total power loss and the stator core loss of the tested motor based on the simplified motor structure, wherein the difference between the total power loss and the stator core loss is the motor winding alternating current loss. According to the method, the actual structure of the stator transposition winding is considered, the loss of the stator winding can be rapidly and accurately measured and calculated, process is easy to realize, and engineering application is facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of motor winding loss measurement. Background Art

[0002] The existing technology constantly pursues high power density of motors, hoping that the lower the loss of the motor, the higher the efficiency. The winding loss of the motor has become one of the key factors restricting development. In order to obtain the efficiency of the motor, it is necessary to obtain the loss source of each component. However, at present, it is difficult to simply and effectively measure the winding loss without increasing the cost of hardware and software, which brings certain difficulties to measuring the winding loss and improving the efficiency of the motor. Summary of the invention

[0003] The present invention aims to solve the problem that it is difficult to simply and effectively measure winding loss without increasing hardware and software costs, and now provides a method and system for measuring AC loss of motor windings.

[0004] A method for measuring AC loss of motor windings, comprising:

[0005] The motor under test is simplified and equivalent to the stator winding and stator core;

[0006] The total power loss and stator core loss of the motor under test are calculated based on the simplified motor structure. The difference between the total power loss and the stator core loss is the AC loss of the motor winding.

[0007] Furthermore, the calculation formula of the above total power loss is:

[0008]

[0009] Where P1 is the total power loss, u1(t) and i1(t) are the voltage and current of the stator winding respectively, and T is the electrical cycle period.

[0010] Furthermore, the voltage calculation formula of the stator winding is:

[0011] u1(t)=i1(t)(R1+X 1σ )-E1,

[0012] Among them, R1 and X 1σ are the resistance and leakage inductance of the stator winding respectively, and E1 is the back electromotive force of the stator winding.

[0013] Furthermore, the calculation formula of the stator core loss is:

[0014]

[0015] Among them, P Fe is the stator core loss, K his the hysteresis loss coefficient, K c is the eddy current loss coefficient, K e is the additional loss coefficient, f is the magnetic field frequency, B m is the magnetic density amplitude.

[0016] A system for measuring AC loss of motor windings, comprising:

[0017] The motor under test is simplified and equivalent to the unit of stator winding and stator core;

[0018] A unit for calculating the total power loss and stator core loss of the motor under test based on the simplified motor structure;

[0019] The total power loss and the stator core loss are subtracted to obtain the unit of AC loss of the motor winding.

[0020] Furthermore, the calculation formula of the above total power loss is:

[0021]

[0022] Where P1 is the total power loss, u1(t) and i1(t) are the voltage and current of the stator winding, respectively, and T is the electrical cycle period. 。

[0023] Furthermore, the voltage calculation formula of the stator winding is:

[0024] u1(t)=i1(t)(R1+X 1σ )-E1,

[0025] Among them, R1 and X 1σ are the resistance and leakage inductance of the stator winding respectively, and E1 is the back electromotive force of the stator winding.

[0026] Furthermore, the calculation formula of the stator core loss is:

[0027]

[0028] Among them, P Fe is the stator core loss, K h is the hysteresis loss coefficient, K c is the eddy current loss coefficient, K e is the additional loss coefficient, f is the magnetic field frequency, B m is the magnetic density amplitude.

[0029] The beneficial effects of the present invention are:

[0030] 1. The present invention proposes a transposed winding loss measurement system and method, which can simulate the real physical structure of the motor, take into account the actual structure of the stator transposed winding, and can realize fast and accurate measurement and calculation of stator winding loss, which is easy to realize process and convenient for engineering application.

[0031] 2. The simplified model calculation and measurement method is low-cost, and the results do not need to be tested under the condition of the whole machine. The error of the winding AC loss obtained is small, the calculation results are accurate and reliable, and have practical engineering significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a simplified schematic diagram of the motor model.

[0033] Figure 2 A schematic diagram comparing the AC loss calculation results and the measurement results provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The following will be combined with the accompanying 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, rather than 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 belong to the scope of protection of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0035] Specific implementation method 1: refer to Figure 1 and Figure 2 Specifically describing this embodiment, a method for measuring AC loss of a motor winding described in this embodiment includes:

[0036] Step Q1: The motor winding is the source of the winding AC loss. In this embodiment, the transposed winding motor is equivalent to a simplified model of the stator transposed winding. Figure 1 As shown, the simplified model includes a stator winding coil and a stator core.

[0037] Step Q2: Based on step Q1, a simplified and equivalent stator winding model is constructed, and an electromagnetic loss calculation model is constructed through basic electromagnetic principles to obtain the winding AC loss.

[0038] The voltage balance equation of the transposed winding is as follows:

[0039] u1(t)=i1(t)(R1+X 1σ )-E1,

[0040] Where, u1(t), i1(t), R1, X 1σThey are the voltage, current, resistance and leakage inductance of the stator transposed winding respectively; E1 is the reverse electromotive force of the winding, and the leakage inductance is ignored.

[0041] The total power loss P1 includes the winding copper loss P cu and stator core loss P Fe , whose expression is:

[0042]

[0043] Where T is the electrical cycle period.

[0044] Stator core loss P Fe for:

[0045]

[0046] In the formula, K h is the hysteresis loss coefficient, K c is the eddy current loss coefficient, K e is the additional loss coefficient, f is the magnetic field frequency, B m is the magnetic density amplitude.

[0047] Step Q3: Obtain winding loss based on the electromagnetic loss model.

[0048] AC loss P of the measured transposed winding cu It is expressed as:

[0049] P cu =P1-P Fe .

[0050] Specific implementation method 2: refer to Figure 1 and Figure 2 Specifically describing this embodiment, a motor winding AC loss measurement system described in this embodiment includes:

[0051] Measurement module: collects the total power loss, voltage and current of the measured transposed winding.

[0052] Model building module: Equivalent the transposed winding motor to a simplified model of the stator transposed winding. Figure 1 As shown, the simplified model includes a stator winding coil and a stator core. Based on the stator winding model, an electromagnetic loss calculation model is constructed through the basic electromagnetic principle.

[0053] Control module: It can adjust and control the motor under test to work at different frequencies, calculate the stator core loss, and then subtract the stator core loss from the total power loss to obtain the motor winding AC loss.

[0054] The voltage balance equation for the transposed winding is as follows:

[0055] u1(t)=i1(t)(R1+X 1σ )-E1,

[0056] Where, u1(t), i1(t), R1, X 1σ They are the voltage, current, resistance and leakage inductance of the stator transposed winding respectively; E1 is the reverse electromotive force of the winding, and the leakage inductance is ignored.

[0057] The total power loss P1 is expressed as:

[0058]

[0059] Where T is the electrical cycle period.

[0060] Stator core loss P Fe for:

[0061]

[0062] In the formula, K h is the hysteresis loss coefficient, K c is the eddy current loss coefficient, K e is the additional loss coefficient, f is the magnetic field frequency, B m is the magnetic density amplitude.

[0063] AC loss P of the measured transposed winding cu It is expressed as:

[0064] P cu =P1-P Fe .

[0065] Power module: Provides power to the measurement module, model building module, and control module.

[0066] Based on the comparison between the transposed winding loss test results and the results obtained by the present invention, the measured results of the AC loss are basically consistent with the calculated results in amplitude. The measured results are slightly larger than the calculated results. This is because the loss of the winding measured is not only the electromagnetic loss generated by the winding current, but also the loss generated by the stator core leakage and harmonics. Therefore, the measured loss not only has AC loss, but also contains a certain core loss. The calculated results only consider the electromagnetic loss of the winding, but in the transposed winding device, the AC loss of the winding accounts for the main part, with a maximum error of 8.2%. Therefore, through the comparison of the results, it can be seen that the AC loss results obtained by the present invention are basically consistent with the measurement results, achieving the expected effect.

[0067] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that the features described in conjunction with a single embodiment may be used in other described embodiments.

Claims

1. A method for measuring AC loss of motor windings, characterized in that: include: The motor under test is simplified and equivalent to the stator winding and stator core; The total power loss and stator core loss of the motor under test are calculated based on the simplified motor structure. The difference between the total power loss and the stator core loss is the AC loss of the motor winding.

2. The method for measuring AC loss of motor winding according to claim 1, characterized in that: The total power loss is calculated as: Where P1 is the total power loss, u1(t) and i1(t) are the voltage and current of the stator winding respectively, and T is the electrical cycle period.

3. The method for measuring AC loss of motor winding according to claim 2, characterized in that: The voltage calculation formula of the stator winding is: u1(t)=i1(t)(R1+X 1σ )-E1, Among them, R1 and X 1σ are the resistance and leakage inductance of the stator winding respectively, and E1 is the back electromotive force of the stator winding.

4. The method for measuring AC loss of motor winding according to claim 1, characterized in that: The calculation formula of the stator core loss is: Among them, P Fe is the stator core loss, K h is the hysteresis loss coefficient, K c is the eddy current loss coefficient, K e is the additional loss coefficient, f is the magnetic field frequency, B m is the magnetic density amplitude.

5. A system for measuring AC loss of motor windings, characterized in that: include: The motor under test is simplified and equivalent to the unit of stator winding and stator core; A unit for calculating the total power loss and stator core loss of the motor under test based on the simplified motor structure; The total power loss and the stator core loss are subtracted to obtain the unit of AC loss of the motor winding.

6. A motor winding AC loss measurement system according to claim 5, characterized in that: The total power loss is calculated as: Where P1 is the total power loss, u1(t) and i1(t) are the voltage and current of the stator winding respectively, and T is the electrical cycle period.

7. A motor winding AC loss measurement system according to claim 6, characterized in that: The voltage calculation formula of the stator winding is: u1(t)=i1(t)(R1+X 1σ )-E1, Among them, R1 and X 1σ are the resistance and leakage inductance of the stator winding respectively, and E1 is the back electromotive force of the stator winding.

8. The motor winding AC loss measurement system according to claim 5, characterized in that: The calculation formula of the stator core loss is: Among them, P Fe is the stator core loss, K h is the hysteresis loss coefficient, K c is the eddy current loss coefficient, K e is the additional loss coefficient, f is the magnetic field frequency, B m is the magnetic density amplitude.

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