Method for measuring eddy current loss of high-speed permanent magnet motor

Abstract

The application provides a kind of eddy current loss measurement method of high-speed permanent magnet motor, comprising: coaxial connection of source motor, power analyzer, measured motor;For the measured motor, configure the insulator rotor without sheath, accelerate the measured motor to rated speed V by source motor, measure the input power of measured motor by power analyzer, record as P1;For the measured motor, configure the insulator rotor with sheath, accelerate the motor to rated speed V by source motor when the measured motor is not excited, measure the input power of motor by power analyzer, record as P2;Subtract the input power P1 of measured motor measured in step two from the input power P2 of measured motor measured in step three, obtain the mechanical loss difference P3 of measured motor rotor in two states of with sheath and without sheath.The loss measurement method of the application can completely reproduce the actual operation of motor under rated operating condition, the required measurement condition is easy to meet, and the measurement result is accurate.

Description

Technical Field

[0001] The present invention relates to a method for measuring motor loss, and in particular to a method for measuring eddy current loss of a high-speed permanent magnet motor. Background Art

[0002] Compact, lightweight, high-speed, high-power motors have broad application prospects in military, medical, and mine rescue applications. They are also urgently needed for the development of high-power airborne power supplies, electric aircraft, and flywheel energy storage. High-speed permanent magnet motors offer the advantages of high energy density and efficiency, and their structural characteristics make them suitable for extremely high-speed operation. The high speed and power density of high-speed permanent magnet motors also lead to relatively large losses in the motor. The high-frequency magnetic field in the air gap directly generates eddy currents in the rotor, forming eddy current losses, which can cause rotor overheating. This is especially true in high-speed motors where the rotor is protected by a sheath with very low thermal conductivity. Rotor overheating can permanently demagnetize the magnets, shorten the bearing life, and damage the retaining sleeve. Therefore, accurately calculating rotor eddy current losses and taking measures to reduce them is crucial for protecting high-speed motors. Currently, commonly used theoretical calculation methods for rotor eddy current losses include analytical methods and finite element methods. However, experimental measurement of eddy current losses has always been a challenge, and current measurement methods suffer from large errors.

[0003] Chinese patent CN113447814A discloses a loss separation device and loss separation method for an ultra-high-speed permanent magnet motor. The device performs a rotor locked test and a rotorless test on an unloaded motor platform, and ensures that the experimental current amplitude and frequency are consistent with the rated operating conditions. The input power of the motor is measured twice. The patent believes that the difference between the two experimental input powers is the eddy current loss. The solution in the patent specifically performs a rotor locked test on an unloaded motor platform, ensures that the experimental current amplitude and frequency are consistent with the rated operating conditions, and measures the motor input power, which is recorded as Pa; performs a rotorless test on an unloaded motor platform, ensures that the experimental current amplitude and frequency are consistent with the rated operating conditions, and measures the motor input power, which is recorded as Pb; the difference between the two measured active powers, Pa-Pb, is the eddy current loss Pe of the rotor of the motor being measured. In theory, this method calculates all losses on the rotor except mechanical losses, but the theoretical error of the calculation result is large. On the one hand, when conducting rotorless tests on a motor under test, the motor must be operated at low voltage. Otherwise, the current will surge, which can easily damage the motor. Furthermore, the low voltage state of the motor causes the motor's magnetic flux density to be very low, and the eddy current losses measured in this state are inconsistent with those when the motor is operating at rated conditions. Furthermore, in motor rotor locked tests, the motor's operating state is inconsistent with the rated operating conditions, making it impossible to guarantee that the current amplitude and frequency under experimental conditions will be consistent with those under rated conditions.

[0004] The existing literature (Zhang M, Luo S, Liu X, et al. The eddy current loss segmentation model of permanent magnet for temperature analysis in high﹕speed permanent magnet motor[J]. IET Power Electronics, 2021, 14(1).) records a method of measuring rotor eddy current loss through a calorific value experimental method. The eddy current loss value is indirectly calculated by the influence of eddy current on the rotor temperature rise. This method cannot directly measure the eddy current loss, and a completely adiabatic environment cannot be achieved. At the same time, heat is a slow variable, and there is no repeatability accuracy through calorific value calculation, which will cause large differences in the experimental results obtained each time. If the calorific value calculation method is used in the calculation of eddy current loss of high-speed motor rotors, the error will be further increased. Summary of the Invention

[0005] In order to solve the above-mentioned problems existing in the prior art, the present application provides a method for measuring the eddy current loss of a high-speed permanent magnet motor. The method has low measurement condition requirements and a simple test process. It can fully reproduce the actual operation of the ultra-high-speed permanent magnet motor under rated working conditions, and accurately measure the mechanical loss and eddy current loss of the high-speed permanent magnet motor rotor while controlling costs.

[0006] Based on the above invention objectives, the present application provides a method for measuring eddy current loss of a high-speed permanent magnet motor, comprising the following steps:

[0007] Step 1: Connect the source motor, power analyzer, and the motor under test coaxially;

[0008] Step 2: The motor under test is equipped with an insulator rotor without a sheath. When the motor under test is not excited, the motor speed is accelerated to the rated speed V by the source motor. After stabilization, the input power of the motor under test at this time is measured by the power analyzer and recorded as P1.

[0009] Step 3: The motor under test is equipped with an insulator rotor with a sheath. When the motor under test is not excited, the motor under test is accelerated to the rated speed V by the source motor. After stabilization, the input power of the motor under test at this time is measured by the power analyzer and recorded as P2.

[0010] Step 4: Subtract the input power P1 of the motor under test measured in step 2 from the input power P2 of the motor under test measured in step 3 to obtain the mechanical loss difference P3 of the motor under test with and without a sheath.

[0011] Step 5: equip the motor under test with an insulator rotor with a sheath, apply excitation to the motor under test so that the motor under test operates under rated operating conditions, and accelerate the motor under test to the rated speed V through the source motor. After stabilization, measure the input power P4 of the motor under test at this time;

[0012] Step 6: equip the motor under test with an insulator rotor without a sheath, apply excitation to the motor under test so that the motor under test operates under rated operating conditions, and accelerate the motor under test to the rated speed V through the source motor. After stabilization, measure the input power P5 of the motor under test at this time;

[0013] Step 7: Subtract the input power P5 of the motor under test measured in step 6 from the input power P4 of the motor under test measured in step 5 to obtain the sum of the mechanical loss difference and eddy current loss P6 of the motor under test in the two states with and without the rotor sheath.

[0014] Step 8: Subtract the mechanical loss difference P3 of the rotor of the motor under test with and without a sheath in step 4 from the sum of the mechanical loss difference and eddy current loss P6 of the rotor of the motor under test with and without a sheath measured in step 7 to obtain the rotor eddy current loss P7 of the motor under test.

[0015] Furthermore, the source motor is set to be a high-speed permanent magnet synchronous motor.

[0016] Furthermore, the rated speed of the source motor is 80,000 r / min and the rated power is 13 kW.

[0017] Furthermore, the rated speed V of the motor under test is set to 80000 r / min.

[0018] Furthermore, the rotor sleeve of the motor under test is set to be a TC4 titanium alloy sleeve.

[0019] Furthermore, the unsheathed insulator rotor and the sheathed insulator rotor of the tested motor have the same structural parameters except whether they are sheathed.

[0020] Based on the above invention objectives, the present application also provides a method for measuring eddy current loss of a high-speed permanent magnet motor, comprising the following steps:

[0021] Step 1: Connect the source motor, power analyzer, and the motor under test coaxially;

[0022] Step 2: Obtain the mechanical loss calibration value of the motor under test at the rated speed V, recorded as P8;

[0023] Step 3: Excite the motor under test and accelerate the motor under test to the rated speed V through the source motor. Calculate the input power of the motor under test at this time and record it as P9.

[0024] Step 4: Remove the rotor and rotor cover of the motor under test, apply the same excitation as in step 3 to the motor under test, and calculate the input power of the motor under test at this time, which is recorded as P10;

[0025] Step 5: Subtract the input power P9 of the motor under test in step 3 from the input power P 10 And the mechanical loss calibration value P8 of the motor under test is used to obtain the rotor eddy current loss P of the motor under test. 11 , that is, P 11 =P9-P 10 -P8.

[0026] Furthermore, the rated speed V of the motor under test is set to 50000 r / min.

[0027] Furthermore, the rotor sleeve of the motor under test is set to be a TC4 titanium alloy sleeve.

[0028] Furthermore, the rotor of the motor under test is set to be an insulator rotor.

[0029] Compared with the prior art, the present invention has the following beneficial effects: by configuring the motor under test with a sheathed and a sheathless rotor and driving the motor under test to operate at the rated speed, the measurement conditions are easy to achieve; during measurement, the motor under test operates under rated conditions, which is harmless to the motor, and the eddy current loss of the motor under rated conditions can be accurately measured. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a flow chart of a measurement method according to an embodiment of the present invention.

[0031] Figure 2 This is a flow chart of another measurement method according to an embodiment of the present invention.

[0032] Figure 3 It is a schematic diagram of the installation structure of the measuring device according to an embodiment of the present invention.

[0033] Figure 4 It is a cross-sectional view of the measuring device when the insulator rotor is in a sheathed state according to an embodiment of the present invention.

[0034] Figure 5 4 is a cross-sectional view of a measuring device when the insulator rotor is in a sheathless state according to an embodiment of the present invention.

[0035] Explanation of the accompanying drawings: 1. source motor; 2. power analyzer; 3. motor under test; 31. insulator rotor; 32. sheath. DETAILED DESCRIPTION

[0036] In order to enable readers to better understand the design purpose of this method, the following specific embodiments are provided to enable readers to vividly understand the structure, structural composition, working principle and technical effects involved in this method. However, it should be noted that the following embodiments are not limitations on the technical solutions of this method. While analyzing and understanding the embodiments, those skilled in the art can combine existing knowledge to make a series of modifications and equivalent substitutions to the technical solutions provided by this method. The new technical solutions obtained by such modifications and equivalent substitutions are also included in this method.

[0037] Example 1:

[0038] like Figure 1 As shown, a method for measuring eddy current loss of a high-speed permanent magnet motor includes the following steps:

[0039] S101, the source motor 1, the power analyzer 2, and the measured motor 3 are coaxially connected; the connection structure between the source motor 1, the power analyzer 2 and the measured motor 3 is as follows Figure 3 As shown, the source motor 1 is used to drive the motor 3 under test, and the output shaft of the source motor 1 is connected to the insulator rotor 31 of the motor 3 under test through the power analyzer 2. The power analyzer 2 is used to measure the input power of the motor 3 under test. The motor 3 under test is a high-speed permanent magnet motor. The source motor is set to a high-speed permanent magnet synchronous motor. The rated speed of the source motor is 80,000 r / min and the rated power is 13 kW. The power analyzer adopts a high-precision, multi-channel LMG671 power analyzer.

[0040] S102, configure the insulator rotor 31 without a sheath 32 for the motor 3 under test, accelerate the speed of the motor 3 under test to the rated speed V through the source motor 1 when the motor 3 under test is not excited, and after it stabilizes, measure the input power of the motor 3 under test at this time through the power analyzer 2, which is recorded as P1.

[0041] S103, configure the insulator rotor 31 with a sheath 32 for the motor 3 under test, accelerate the speed of the motor 3 under test to the rated speed V through the source motor 1 when the motor 3 under test is not excited, and after it stabilizes, measure the input power of the motor 3 under test at this time through the power analyzer 2, which is recorded as P2.

[0042] S104 , subtracting the input power P1 of the motor 3 under test measured in step S102 from the input power P2 of the motor 3 under test measured in step S103 , to obtain a mechanical loss difference P3 between the rotor of the motor under test with and without a sheath.

[0043] S105, equipping the motor 3 with an insulator rotor 31 with a sheath 32, applying excitation to the motor 3 so that the motor 3 operates under rated conditions, and accelerating the motor 3 to a rated speed V by the motor 1. After stabilization, the input power P4 of the motor is measured.

[0044] S106, equipping the motor 3 with an unsheathed insulator rotor 31, applying excitation to the motor 3 so that the motor 3 operates under rated conditions, and accelerating the motor 3 to a rated speed V by the motor 1. After stabilization, the input power P5 of the motor 3 is measured.

[0045] S107, subtract the input power P5 of the motor 3 under test measured in step S106 from the input power P4 of the motor 3 under test measured in step S105, and obtain the sum of the mechanical loss difference and eddy current loss P6 of the motor 3 under test when the insulator rotor 31 has a sheath 32 and when it does not have a sheath.

[0046] S108, subtract the sum of the mechanical loss difference P3 of the rotor of the tested motor with and without a sheath in step S104 from the sum of the mechanical loss difference P6 of the rotor of the tested motor 3 with and without a sheath and the eddy current loss measured in step S107, to obtain the rotor eddy current loss P7 of the tested motor 3.

[0047] In a high-speed permanent magnet motor, it is difficult for the permanent magnet to withstand the huge centrifugal force when rotating at high speed and working for a long time. Protective measures must be taken for the permanent magnet. The two most commonly used protective measures are carbon fiber bundling permanent magnets and alloy protective sleeves on the permanent magnets. At the same time, the protective measures will increase the eddy current loss of space and time harmonics in the rotor, which brings great difficulties to the heat dissipation of the high-speed permanent magnet motor, resulting in excessive temperature rise of the motor rotor and irreversible demagnetization of the permanent magnet. Therefore, the eddy current loss in the high-speed permanent magnet motor mainly comes from the sleeve made of various materials such as alloy or carbon fiber. When the motor insulator rotor has no sleeve, the eddy current loss is very small and can be ignored. Moreover, eddy current loss will only be generated when the motor is excited. When no excitation is applied, there is no eddy current loss, only mechanical loss. Therefore, in this embodiment, the source motor 1 drives the motor 3 under test without Under the condition of excitation, the motor 3 under test is operated at the rated speed and the power analyzer is used to measure the two input powers of the motor 3 under test when it is with a sheath and when it is not with a sheath when there is no eddy current loss. The mechanical loss difference caused by the addition of the sheath 32 is separated by the difference between the two input powers. Then, under the condition of applying rated excitation, the two input powers when it is with a sheath and when it is not with a sheath are also measured respectively. The input power when the excitation is applied with the sheath contains both eddy current loss and mechanical loss difference caused by the sheath. The eddy current loss of the insulator rotor of the motor under test 3 caused by the addition of the sheath can be obtained by subtracting the mechanical loss difference caused by the sheath and the input power of the motor without the sheath from this input power. The eddy current loss of the high-speed permanent magnet motor rotor without a sheath is very small and can be ignored. Therefore, the eddy current loss caused by the motor rotor sheath can be equated with the eddy current loss of the motor under test 3.

[0048] As an implementation method, the rated speed V of the motor 3 under test is set to 80000 r / min.

[0049] As an implementation method, the rotor sheath 32 of the motor 3 under test is set to a TC4 titanium alloy sheath. Since the rotor of the ultra-high-speed motor will generate a large centrifugal force when it is running, a sheath made of carbon fiber or metal alloy material is generally used to protect the rotor. This embodiment takes the TC4 titanium alloy sheath as an example, and sheaths made of other materials can also be used.

[0050] As an implementation method, the structural parameters of the insulator rotor 31 without a sheath 32 and the insulator rotor 31 with a sheath 32 of the motor 3 under test are consistent except whether they have a sheath 32. In order to ensure the accuracy of the measurement results, the structural parameters of the insulator rotor 31 without a sheath 32 and the insulator rotor 31 with a sheath 32 of the motor 3 under test are consistent except whether they have a sheath 32.

[0051] In summary, compared with the prior art, this embodiment has the following beneficial effects:

[0052] (1) The measurement device of this embodiment can be built by simply connecting the source motor 1, the power analyzer 2, and the measured motor 3 coaxially. There are no other requirements for the experimental conditions and it is easy to implement. In addition, the measured motor 3 runs at the rated speed in each step, which is harmless to the motor. It can accurately reflect the rotor eddy current loss of the high-speed permanent magnet motor under rated working conditions.

[0053] (2) The measurement principle is based on the source of eddy current loss and eliminates other losses that may be generated during the operation of the motor through multiple measurements, which greatly improves the calculation accuracy of the motor's eddy current loss. It reduces the experimental error in the calculation of eddy current loss while significantly reducing the theoretical error.

[0054] (3) The problem of being unable to increase the voltage and low magnetic flux density due to the lack of a rotor core is solved. The actual operation of the high-speed motor under rated conditions can be fully reproduced, and the eddy current loss of the motor during actual operation can be accurately measured.

[0055] (4) While ensuring the calculation accuracy, the experimental conditions are easy to meet and the measurement repeatability is good.

[0056] (5) This solution directly measures eddy current loss through experimental methods, solving the problems of long calculation time and high resource consumption caused by the finite element method and large errors caused by the analytical method in model simplification.

[0057] Example 2

[0058] As another implementation of the present invention, Figure 2 As shown, a method for measuring eddy current loss of a high-speed permanent magnet motor includes the following steps:

[0059] S201, the source motor 1, the power analyzer 2, and the measured motor 3 are coaxially connected; the connection structure between the source motor 1, the power analyzer 2 and the measured motor 3 is as follows Figure 3 As shown, the source motor 1 is used to drive the motor 3 under test, and the output shaft of the source motor 1 is connected to the insulator rotor 31 of the motor 3 under test through the power analyzer 2. The power analyzer 2 is used to measure the input power of the motor 3 under test. The motor 3 under test is a high-speed permanent magnet motor. The source motor is set to a high-speed permanent magnet synchronous motor. The rated speed of the source motor is 80,000 r / min and the rated power is 13 kW. The power analyzer adopts a high-precision, multi-channel LMG671 power analyzer.

[0060] S202 , obtaining a mechanical loss calibration value of the motor 3 under test at a rated speed V, recorded as P8.

[0061] In step S203, motor 3 under test is excited and accelerated to a rated speed V by motor 1. The input power of motor 3 under test at this point is calculated and recorded as P9. The input power P9 is the sum of the motor's power and other losses under rated operating conditions, excluding rotor eddy current losses and mechanical losses.

[0062] S204 , remove the rotor and rotor cover 32 of the motor 3 under test, apply the same excitation as in step S203 to the motor 3 under test, and calculate the input power of the motor 3 under test at this time, which is recorded as P10.

[0063] S205 , subtract the input power P10 of the motor 3 under test in step S204 and the mechanical loss calibration value P8 of the motor 3 under test from the input power P9 of the motor 3 under test in step S203 to obtain the rotor eddy current loss P11 of the motor 3 under test, that is, P11 = P9 - P10 - P8.

[0064] In step S203, the rotor casing of the motor 3 under test is removed and excitation under rated operating conditions is applied to calculate the input power P9 of the motor 3 under test at this time. This input power is the input power of the motor 3 under test after removing the rotor mechanical loss and eddy current loss. The input power P9 is subtracted from the input power P10 of the motor 3 under test obtained in step S204 and then subtracted from the mechanical loss calibration value P8 at the rated speed V of the motor 3 under test to obtain the rotor eddy current loss P11 of the motor 3 under test.

[0065] As an implementation method, the rated speed V of the motor 3 under test is set to 50000 r / min.

[0066] As an implementation method, the rotor sheath 32 of the motor under test 3 is configured as a TC4 titanium alloy sheath 32. Because the rotor of an ultra-high-speed motor generates significant centrifugal force during operation, a sheath made of carbon fiber or metal alloy is typically used to protect the rotor. While this embodiment uses a TC4 titanium alloy sheath as an example, sheaths made of other materials may also be used.

[0067] As an implementation manner, the rotor of the motor 3 under test is set to be an insulator rotor 31.

[0068] This embodiment is a relatively convenient method for measuring the motor under test at a relatively low speed in Example 1, and its beneficial effects are as follows:

[0069] (1) The measurement device of this embodiment can be built by simply connecting the source motor 1, the power analyzer 2, and the measured motor 3 coaxially. There are no other requirements for the experimental conditions and it is easy to implement. In addition, the measured motor 3 runs at the rated speed in each step, which is harmless to the motor. It can accurately reflect the rotor eddy current loss of the high-speed permanent magnet motor under rated working conditions.

[0070] (2) The measurement principle is based on the source of eddy current loss and eliminates other losses that may be generated during the operation of the motor through multiple measurements, which greatly improves the calculation accuracy of the motor's eddy current loss. It reduces the experimental error in the calculation of eddy current loss while significantly reducing the theoretical error.

[0071] (3) While ensuring the calculation accuracy, the experimental conditions are easy to meet and the measurement repeatability is good.

[0072] (4) This solution directly measures eddy current loss through experimental methods, solving the problems of long calculation time and high resource consumption caused by the finite element method and large errors caused by the analytical method in model simplification.

[0073] To sum up, by configuring the motor 3 under test with a rotor with a sheath 32 and a rotor without a sheath 32 and driving the motor 3 under test to operate at the rated speed, the measurement conditions are easy to achieve; during measurement, the motor 3 under test operates under rated conditions, which is harmless to the motor, and the eddy current loss of the motor under rated conditions can be accurately measured.

[0074] It should be understood that for those skilled in the art, improvements or changes can be made based on the above description, and all such improvements and changes should fall within the scope of protection of the claims attached to the present invention. The drawings corresponding to the specific implementation plans exist in the form of auxiliary understanding, which can facilitate readers to fully understand the abstract higher-level concepts of the technical concepts involved in this method by understanding the specific and figurative lower-level concepts. When understanding the overall understanding of this method and comparing it with other technical solutions other than the technical solutions provided by this method, the appearance of the drawings should not be used as the only reference basis. After understanding the concept of this method, a series of deformations, equivalent substitutions, combinations of characteristic elements, deletions and reorganizations of non-essential technical characteristic elements, and reasonable additions and reorganizations of non-essential technical characteristic elements commonly used in the prior art should be understood as being included in the spirit of this method.

Claims

1. A method for measuring eddy current loss of a high-speed permanent magnet motor, characterized in that: The following steps are involved: Step 1: Connect the source motor, power analyzer, and the motor under test coaxially; Step 2: equip the motor under test with an insulator rotor without a sheath, accelerate the motor under test to a rated speed V by the source motor when the motor under test is not excited, and measure the input power of the motor under test at this time by the power analyzer after stabilization, which is recorded as P1; Step 3: equip the motor under test with an insulator rotor with a sheath, accelerate the motor under test to a rated speed V by the source motor when the motor under test is not excited, and measure the input power of the motor under test at this time by the power analyzer after stabilization, which is recorded as P2; Step 4: Subtract the input power P1 of the motor under test measured in step 2 from the input power P2 of the motor under test measured in step 3 to obtain the mechanical loss difference P3 of the motor under test with and without a sheath; Step 5: equip the motor under test with an insulator rotor with a sheath, apply excitation to the motor under test so that the motor under test operates under rated operating conditions, and accelerate the speed of the motor under test to the rated speed V by the source motor. After stabilization, measure the input power P4 of the motor under test at this time; Step 6: equip the motor under test with an insulator rotor without a sheath, apply excitation to the motor under test so that the motor under test operates under rated operating conditions, and accelerate the speed of the motor under test to the rated speed V by the source motor. After stabilization, measure the input power P5 of the motor under test at this time; Step 7: Subtract the input power P5 of the motor under test measured in step 6 from the input power P4 of the motor under test measured in step 5 to obtain the sum of the mechanical loss difference and eddy current loss of the motor under test when the rotor is covered and when it is not covered. Step 8: Subtract the mechanical loss difference P3 of the rotor of the motor under test with and without a sheath from the sum of the mechanical loss difference and eddy current loss P6 of the rotor of the motor under test with and without a sheath measured in step 7, to obtain the rotor eddy current loss P7 of the motor under test; The eddy current loss caused by the sheath is equivalent to the eddy current loss of the motor under test.

2. The method for measuring eddy current loss of a high-speed permanent magnet motor according to claim 1, wherein: The source motor is set as a high-speed permanent magnet synchronous motor.

3. The method for measuring eddy current loss of a high-speed permanent magnet motor according to claim 2, wherein: The rated speed of the source motor is 80,000 r / min and the rated power is 13 kW.

4. The method for measuring eddy current loss of a high-speed permanent magnet motor according to claim 1, wherein: The rated speed V of the motor under test is set to 80000 r / min.

5. The method for measuring eddy current loss of a high-speed permanent magnet motor according to claim 1, wherein: The rotor sleeve of the motor under test is set to be a TC4 titanium alloy sleeve.

6. The method for measuring eddy current loss of a high-speed permanent magnet motor according to claim 1, wherein: The unsheathed insulator rotor and the sheathed insulator rotor of the motor under test have the same structural parameters except whether they are sheathed.

7. A method for measuring eddy current loss of a high-speed permanent magnet motor, characterized in that: The following steps are involved: Step 1: Connect the source motor, power analyzer, and the motor under test coaxially; Step 2: Obtain a mechanical loss calibration value of the motor under test at a rated speed V, recorded as P8; Step 3: applying excitation to the motor under test and accelerating the motor under test to a rated speed V through the source motor, and calculating the input power of the motor under test at this time as P9; Step 4: Remove the rotor and rotor cover of the motor under test, apply the same excitation as in step 3 to the motor under test, and calculate the input power of the motor under test at this time, which is recorded as P 10 ; Step 5: Subtract the input power P9 of the motor under test in step 3 from the input power P 10 And the mechanical loss calibration value P8 of the motor under test is used to obtain the rotor eddy current loss P of the motor under test. 11 , that is, P 11 =P9-P 10 -P8; The eddy current loss caused by the sheath is equivalent to the eddy current loss of the motor under test.

8. The method for measuring eddy current loss of a high-speed permanent magnet motor according to claim 7, wherein: The rated speed V of the motor under test is set to 50000 r / min.

9. The method for measuring eddy current loss of a high-speed permanent magnet motor according to claim 7, wherein: The rotor sleeve of the motor under test is set to be a TC4 titanium alloy sleeve.

10. The method for measuring eddy current loss of a high-speed permanent magnet motor according to claim 7, wherein: The rotor of the motor under test is set as an insulator rotor.

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