Control method for testing temperature rise of winding

Abstract

The invention provides a control method for testing the temperature rise of a winding, and the method comprises the steps: enabling a controller to control a tested permanent magnet motor to carry out no-load testing at a rated rotating speed when the tested permanent magnet motor is in an inorganic sealing state and an organic sealing state, and testing the input power P null input 1 and P null input 2 of the tested permanent magnet motor and the generated current I null 1 and I null 2; the copper loss P < empty copper loss >, the iron loss P < empty iron loss > and the mechanical loss P < friction > are calculated respectively; measuring the phase resistance R cold of the measured permanent magnet motor; the counter electromotive force E cold of the measured permanent magnet motor in the cold state is measured; a cold-state load test: testing the input power P cold-in, the output power P cold-out and the input current I cold when the tested permanent magnet motor works at a preset load under rated power, and a hot-state temperature rise test: adjusting the tested permanent magnet motor to run at the same output power as the tested permanent magnet motor in a cold state, recording the input power P heat-in, the output power P heat-out, the input current I heat and the counter electromotive force E heat of the tested permanent magnet motor in the thermal state; and T = T-T0 is calculated.

Description

Technical Field

[0001] This invention belongs to the field of permanent magnet motor technology, and in particular relates to a control method for testing the temperature rise of windings. Background Technology

[0002] Permanent magnet motors are widely used in many fields due to their high efficiency, high power, low maintenance requirements and good dynamic response characteristics.

[0003] For example, applications include industrial automation, new energy vehicles, wind power generation, home appliances, medical equipment, aerospace, agriculture, shipbuilding and marine engineering, compressors and pumps, etc. Temperature rise has always been a key research issue for permanent magnet motors.

[0004] Current methods for testing the temperature rise of permanent magnet motors include the resistance method and the thermocouple method. The thermocouple method requires embedding thermistors, thermocouples, or other devices that can detect the temperature rise of the windings in the permanent magnet motor windings. This method requires external lead-out detection wires and is not suitable for some products with high sealing requirements.

[0005] The resistance method is a method of measuring temperature rise based on the characteristic that the resistance of the copper wire in the winding increases synchronously with the increase in temperature. The resistance method requires measuring the cold-state resistance and the hot-state resistance, and then using the difference between these values ​​and the coefficient of resistance change with temperature rise to calculate the temperature rise of the winding.

[0006] However, the drawback of the resistance method for testing winding temperature rise is that the permanent magnet motor needs to be stopped before testing the hot resistance. After the motor stops, the heat source of the permanent magnet motor is no longer generating heat, and the motor is in a heat dissipation state. This results in a time lag when testing the hot resistance, and the actual measured value will be lower than the actual value.

[0007] Although the hot resistance was tested multiple times, such as once every predetermined time interval (e.g., once every few seconds), and multiple sets of data were collected to correct the hot resistance, the results were still somewhat inaccurate and could not be as close to the actual value as expected. Summary of the Invention

[0008] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a control method for testing the temperature rise of the winding, which calculates the temperature rise of the motor winding indirectly without adding extra workload, and the calculation result is accurate.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] A method for controlling the temperature rise of a test winding, comprising the following steps:

[0011] S1. The controller controls the permanent magnet motor under test to perform a no-load test at its rated speed without an mechanical seal, and tests the input power P of the permanent magnet motor under test. 空输入1 and the current I generated under no-load conditions 空1 ;

[0012] The controller controls the permanent magnet motor under test to perform a no-load test at its rated speed when it is sealed, and the input power P of the permanent magnet motor under test is tested. 空输入2 and the current I generated under no-load conditions 空 2;

[0013] According to the input power P 空输入1 The copper loss P of the permanent magnet motor under test 空铜损 Iron loss P 空铁损 The sum of, and P 空输入2 The copper loss P of the permanent magnet motor under test 空铜损 Iron loss P 空铁损 and mechanical loss P 摩擦 The sum of these values ​​is used to calculate the copper loss P. 空铜损 Iron loss P 空铁损 Friction and mechanical loss P;

[0014] S2. Measure the phase resistance R of the permanent magnet motor under static conditions. 冷 ;

[0015] S3. Drive the permanent magnet motor under test to rotate to a predetermined speed, and when the back electromotive force of the permanent magnet motor under test reaches a stable value, measure the back electromotive force E of the permanent magnet motor under test in the cold state. 冷 ;

[0016] S4. Cold Load Test: Tests the input power P of the permanent magnet motor under test when it operates at rated power and under a predetermined load. 冷入 Output power P 冷出 and input current I 冷 , where P 冷铁I =P 冷入 -P 冷出 -P 冷铜 -P 空铁损 -P 摩擦 ;

[0017] S5. Hot-state temperature rise test: Adjust the permanent magnet motor under test to operate at the same output power as the permanent magnet motor under test in the cold state in step S4, and monitor the temperature of the casing in real time. When the temperature change of the casing within a preset time is less than a preset value, record the input power P of the permanent magnet motor under test in the hot state at this time. 热入 Output power P 热出 Input current I 热 and the back electromotive force E in the hot state 热 ;

[0018] Among them, P 热铁 =P 空铁损 *E 冷 / E 热 ;P 热铁I =P 冷铁I *I 热 / I 冷 ;

[0019] P 热入 =P 热出 +P 热铜 +P 热铁I +P 热铁 P 冷出 =P 热出 ;

[0020] Calculate P 热铜 =P 热入 -P 冷出 -P 冷铁I *I 热 / I 冷 -P 空铁损 *E 冷 / E 热 -P 摩擦 ;

[0021] S6, according to R t =P 热铜 / I 热 2 =R 冷 [1+K(T-T0)], calculate △T=T-T0, where R t R is the resistance in the hot state. 冷 Let T be the cold resistance, K be the material constant, T be the hot temperature, and T0 be the cold temperature.

[0022] Preferably, in step S1, when the permanent magnet motor under test has no mechanical seal, a no-load test is performed at the rated speed, and the input power P... 空输入1 =P 空铁损 +P 空铜损1 P 摩擦 =0;

[0023] When the permanent magnet motor under test has an organic seal, a no-load test is performed on the permanent magnet motor under test at its rated speed, wherein P 空输入2 =P 空铁损 +P 空铜损2 +P 摩擦 ;

[0024] Calculate P 摩擦 =P 空输入2 -P 空输入1 -P 空铜损1 -P 空铜损2 , where P 空铜损1 =P 空铜损2=0, or P 空铜损1 =3I 空 1 2 R, I 空1 P represents the no-load current generated by the tested permanent magnet motor without an inorganic seal. 空铜损2 =3I 空2 2 R, I 空2 The current generated by the tested permanent magnet motor under no-load conditions when it is sealed.

[0025] Preferably, in step S1, the input power of the permanent magnet motor under test is tested using a power measuring instrument.

[0026] Preferably, in step S2, a multimeter is used to measure the phase resistance R of the permanent magnet motor under static conditions. 冷 .

[0027] Preferably, in step S4, the back electromotive force E of the permanent magnet motor is measured using a multimeter or power analyzer. 冷 .

[0028] Preferably, the predetermined rotational speed is 1000 r / min.

[0029] Preferably, the preset value is 1K.

[0030] Preferably, the preset time is at least 30 minutes;

[0031] Preferably, in step S5, a thermocouple is installed on the housing of the permanent magnet motor under test, and the thermocouple detects the temperature of the housing in real time.

[0032] Compared with the prior art, the present invention has the following advantages: the present invention does not require testing the hot resistance of the permanent magnet motor, thus avoiding the error caused by the cooling of the hot resistance after the motor stops.

[0033] All the tests in this invention are mandatory items in the performance testing of the permanent magnet motor being tested, and will not add extra workload.

[0034] Furthermore, there is no need to test the resistance of the permanent magnet motor separately when it is in hot operation. Based on the law of conservation of energy, the temperature rise of the winding can be obtained by analyzing the experimental data, resulting in more accurate test results. Attached Figure Description

[0035] Figure 1 This is a flowchart of the method for controlling the temperature rise of the test winding in this invention. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0038] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0039] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0040] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0041] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0042] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0043] like Figure 1 As shown, this embodiment provides a control method for testing the temperature rise of a winding. This control method calculates the temperature rise of the winding based on the conservation of energy, thus eliminating the need to measure the hot resistance.

[0044] When the permanent magnet motor in this embodiment is working, the input power = output power + loss. The loss is divided into copper loss generated after the winding is energized, iron loss in the stator core and mechanical loss. The mechanical loss is the friction loss of the motor's mechanical seal and bearings. The mechanical seal is a key component where leakage occurs between the rotating shaft and the motor end cover.

[0045] Copper loss can be calculated using the formula P = 3I. 2 R is calculated, where I is the motor phase current and R is the motor phase resistance.

[0046] The control methods for the temperature rise of the test winding mentioned above include:

[0047] S1. The controller controls the permanent magnet motor under test to perform a no-load test at its rated speed without an mechanical seal, and tests the input power P of the permanent magnet motor under test. 空输入1 and the current I generated under no-load conditions 空1 ;

[0048] The controller controls the permanent magnet motor under test to perform a no-load test at its rated speed when it is sealed, and the input power P of the permanent magnet motor under test is tested. 空输入2 and the current I generated under no-load conditions 空 2;

[0049] According to the input power P 空输入1 The copper loss P of the permanent magnet motor under test 空铜损 Iron loss P空铁损 The sum of, and P 空输入2 The copper loss P of the permanent magnet motor under test 空铜损 Iron loss P 空铁损 and mechanical loss P 摩擦 The sum of these values ​​is used to calculate the copper loss P. 空铜损 Iron loss P 空铁损 And mechanical wear P friction.

[0050] The rated speed is determined by the speed of the permanent magnet motor under the rated power, based on the design requirements.

[0051] Under no-load conditions, a small current will be generated to overcome the frictional torque. To make the data more accurate, the copper loss of the tested permanent magnet motor can be calculated using the copper loss calculation formula. When the current value is small, the copper loss of the tested permanent magnet motor can be ignored.

[0052] Iron loss and mechanical loss can be obtained from the no-load test data of the permanent magnet motor under test. Specifically, the no-load test is conducted when the motor is not under load and only has speed. The input power of the motor at this time is the sum of iron loss and mechanical loss caused by the permanent magnet.

[0053] If the permanent magnet motor under test has no mechanical seal, such as a mechanical seal or O-ring, which would cause frictional loss to the permanent magnet motor, the mechanical frictional loss caused by the bearing is very small. Therefore, the input power of the permanent magnet motor under test when it is unloaded is the iron loss.

[0054] That is, when the permanent magnet motor under test has no mechanical seal, a no-load test is performed once, and the input power P is... 空输入1 =P 空铁损 +P 空铜损1 P 摩擦 =0;

[0055] When the permanent magnet motor under test has an organic seal, the tests are performed separately for the permanent magnet motor with and without an inorganic seal. The P... 空输入2 =P 空铁损 +P 空铜损2 +P 摩擦 ;

[0056] P is calculated accordingly. 摩擦 =P 空输入2 -P 空输入1 -P 空铜损1 -P 空铜损2 , where P 空铜损1 =P 空铜损2 =0, or P 空铜损1 =3I 空1 2 R, I 空1 P represents the no-load current generated by the tested permanent magnet motor without an inorganic seal. 空铜损2 =3I空2 2 R, I 空2 The current generated by the tested permanent magnet motor under no-load conditions when it is sealed.

[0057] S2. Measure the phase resistance R of the permanent magnet motor under static conditions using a multimeter. 冷 ;

[0058] S3. Drive the permanent magnet motor under test to rotate to 1000 r / min using the drive motor, and measure the back electromotive force E of the permanent magnet motor under test in the cold state using a multimeter or power analyzer. 冷 .

[0059] At this speed, the back electromotive force of the permanent magnet motor under test is a constant.

[0060] S4. Cold Load Test: Tests the input power P of the permanent magnet motor under test when it operates at rated power and under a predetermined load. 冷入 Output power P 冷出 and input current I 冷 .

[0061] The input power P tested 冷入 and output power P 冷出 The difference is the sum of the loss values, which include copper loss P. 冷铜 and iron loss P 冷铁 When the tested permanent magnet motor operates under load, the iron loss generated includes both the input current and the permanent magnet.

[0062] Under cold load testing, the iron loss caused by current is P. 冷铁I Iron loss P caused by current 冷铁I With input current I 冷 The iron loss P generated by the permanent magnet is proportional to the iron loss P generated by the permanent magnet. 冷铁 The iron loss under no-load conditions is P. 空铁损 .

[0063] That is: P 冷入 =P 冷出 +P 冷铜 +P 冷铁I +P 空铁损 +P 摩擦 .

[0064] Output power P 冷出 It is a fixed value, P 冷铜 According to the copper loss calculation formula P 冷铜 =3I 冷 2 R is derived from the phase resistance R. 冷 and input current I 冷 This can be obtained during cold load testing. P 空铁损The input power P was obtained during no-load testing. 冷入 This can also be obtained in this test; therefore, P can be calculated. 冷铁I =P 冷入 -P 冷出 -P 冷铜 -P 空铁损 -P 摩擦 .

[0065] S5. Hot-state temperature rise test: The permanent magnet motor under test is adjusted to operate at the same output power as the permanent magnet motor under cold conditions. Thermocouples are attached to the surface of the motor housing to monitor the housing temperature in real time. When the temperature change of the housing within a preset time is less than a preset value, the temperature rise of the permanent magnet motor is considered to have stabilized. The input power P under hot conditions at this time is recorded. 热入 Output power P 热出 Input current I 热 and the back electromotive force E in the hot state 热 In this embodiment, the preset time is at least 30 minutes. More preferably, the preset time is 30 minutes. The preset value for temperature change is 1 K.

[0066] After the temperature rise stabilizes, a set of back EMFs is measured on the permanent magnet motor under test in the hot state. The back EMF at this time is the hot-state back EMF E. 热 .

[0067] Because the temperature of the permanent magnet motor under test rises after running for a certain period of time, in order to keep the output power the same as that under cold load testing, the current I must be greater than the current value under cold conditions. During hot temperature rise testing, the temperature of the permanent magnet inside the permanent magnet motor rises and the magnetism weakens. In order to maintain the same output power, the current value needs to be increased to maintain the balance between the two phases.

[0068] P 热入 =P 热出 +P 热铜 +P 热铁I +P 热铁 +P 摩擦 .

[0069] The above input power P 热入 and output power P 热出 This can be obtained during hot temperature rise testing.

[0070] Iron loss P generated by permanent magnet 热铁 It can be determined based on the cold back electromotive force E. 冷 The back electromotive force E in the hot state 热 The back electromotive force E in the hot state was obtained through proportional calculation. 热 and the back potential E in the cold state 冷 The value can be determined based on E. 热 and E 冷The loss P generated by the permanent magnet in the hot state is calculated proportionally. 热铁 E 热 E 冷 =P 空铁损 :P 热铁 Since the back electromotive force is caused by the rotor magnetic field, the magnetism generated by the permanent magnet changes linearly between the cold and hot states. Therefore, the iron loss generated by the permanent magnet can be linearly calculated. The linear relationship between the cold and hot states of the permanent magnet results in a remanence temperature coefficient of -0.11 / 1K.

[0071] P 热铁I It can be based on the cold input current I 冷 and hot input current I 热 It is obtained through proportional calculation, i.e., I 冷 :I 热 =P 冷铁I :P 热铁I That is, only thermal P. 热铜 unknown.

[0072] The copper P value is obtained from the calculation using the above formula. Combining this with the hot-state current value and the copper loss calculation formula, the hot-state resistance value R can be obtained. t =P 热铜 / I 热 2 In this embodiment, the cold state refers to the room temperature of the permanent magnet motor under test at the start of the test. The hot state refers to the permanent magnet motor under test operating at the same output power as the permanent magnet motor under test in the cold state in step S4, until the temperature change of the permanent magnet motor casing within a preset time is less than a preset value. Then, the operating state of the permanent magnet motor under test is the hot stable state.

[0073] S6, according to formula R t =R 冷 [1+K(T-T0)], where R t R is the resistance in the hot state. 冷 Let T be the cold resistance, K be the material constant (the coefficient by which the winding resistance is affected by temperature changes), T be the hot temperature, and T0 be the cold temperature. In the formula, all values ​​except T are known, so the winding temperature in the hot state can be calculated. The temperature rise is ΔT = T - T0.

[0074] The T0 mentioned above is the room temperature of the permanent magnet motor under test in its initial working state, which is measured when the permanent magnet motor starts working.

[0075] In this embodiment, it is not necessary to test the hot resistance of the permanent magnet motor, thus avoiding the test error caused by the temperature difference generated by the motor cooling after the motor stops.

[0076] All of the above tests are mandatory items in the performance testing of the permanent magnet motor being tested, and will not add extra workload.

[0077] Furthermore, there is no need to test the resistance of the permanent magnet motor separately when it is in hot operation. Based on the law of conservation of energy, the temperature rise of the winding can be obtained by analyzing the experimental data, resulting in more accurate test results.

[0078] In this embodiment, the order of steps S1-S5 can be adjusted.

[0079] In this embodiment, the temperature rise of the tested permanent magnet motor is calculated under both inorganic and organic seal conditions.

[0080] This embodiment describes the testing process for the permanent magnet motor under test when there is no inorganic seal:

[0081] Cold load test: P 冷输入 =P 冷输出 +P 冷铜 +P 冷铁I +P 冷铁 ;

[0082] Hot load test: P 热输入 =P 冷输出 +P 热铜 +P 热铁I +P 热铁 ;

[0083] P 冷输入 This refers to the input power during cold-state rated load testing.

[0084] P 冷输出 Rated output power;

[0085] P 冷铜 Copper loss during cold load testing;

[0086] P 冷铁I Iron loss caused by load current during cold load testing;

[0087] P 冷铁 The iron loss caused by the rotor permanent magnet under cold load is equivalent to the iron loss under no-load.

[0088] P 热输入 This refers to the input power during hot-state rated load testing.

[0089] P 热铜 Copper loss during hot load testing;

[0090] P 热铁I Iron loss caused by load current during hot load testing;

[0091] P热铁 Iron loss caused by the rotor permanent magnet under hot load;

[0092] P 冷铜 =3I 冷 2 R 冷 ;I 冷 For cold load current, R 冷 The resistance is in the cold phase.

[0093] According to the cold load test, P 冷输入 P 输出 P 冷铜 P 冷铁 As the results have been obtained, only P is present in the cold-state formula. 冷铁I Unknown, therefore P 冷铁I =P 冷输入 -P 输出 -P 冷铜 -P 冷铁 =P 冷输入 -P 输出 -3I 冷 2 R 冷 -P 冷 iron;

[0094] P 冷铁I The iron loss is caused by the load current, therefore the iron loss per unit current is P9 = P 冷铁I / Icold;

[0095] According to the hot load temperature rise test, when the temperature reaches a stable state, P 热输入 P 输出 Given that P 热铜 P is the number that needs to be calculated. 热铁I =P9*I 热 =P 冷铁I / I 冷 *I 热 I 热 P represents the current value when the temperature rise test under hot load stabilizes. 热铁 The iron loss, P, is caused by the rotor permanent magnet when the temperature rise test under hot load stabilizes. 热铁 =P 冷铁 / E 冷 *E 热 E 冷 It is the cold back potential, E 热 E is the hot back potential. 冷 E 热 All of this can be determined through testing.

[0096] According to the above P 热铜 =P 热输入 -P 输出 -P热铁I -P 热铁 =P 热输入 -P 输出 -P 冷铁I / I 冷 *I 热 -P 冷铁 / E 冷 *E 热 ;

[0097] Copper loss P in hot state 热铜 =3*I 热 2 *R t I 热 P 热铜 Given, solve R t .

[0098] R t =P 热铜 / 3 / I 热 2 ;

[0099] The winding temperature rise can be calculated using the resistance method temperature rise formula:

[0100] T-T0=(R t -R 冷 ) / R 冷 K.

[0101] In another embodiment, the testing process for the permanent magnet motor under test when it is organically sealed is given as follows:

[0102] The tested permanent magnet motor with an organic seal has an additional friction loss P caused by the mechanical seal compared to the state without an inorganic seal. 摩擦 The permanent magnet motor under test needs to overcome the frictional loss P generated by the mechanical seal. 摩擦 Only then can it function properly.

[0103] The frictional loss P caused by the mechanical seal can be obtained from the above no-load test. 摩擦 =P 空输入2 -P 空输入1 -P 空铜损1 -P 空铜损2 , where P 空铜损1 =P 空铜损2 =0, or P 空铜损1 =3I 空1 2 R, I 空1 P represents the no-load current generated by the tested permanent magnet motor without an inorganic seal. 空铜损2 =3I 空2 2 R, I 空2 The current generated by the tested permanent magnet motor under no-load conditions when it is sealed.

[0104] Cold state: P 冷输入 =P 冷输出 +P 冷铜 +P 冷铁I +P 冷铁 +P 摩擦 ;

[0105] Hot state: P 热输入 =P 冷输出 +P 热铜 +P 热铁I +P 热铁 +P 摩擦 ;

[0106] P 冷输入 This refers to the input power during cold-state rated load testing.

[0107] P 冷输出 Rated output power;

[0108] P 冷铜 Copper loss during cold load testing;

[0109] P 冷铁I Iron loss caused by load current during cold load testing;

[0110] P 冷铁 The iron loss caused by the rotor permanent magnet under cold load is equivalent to the iron loss under no-load.

[0111] P 热输入 This refers to the input power during hot-state rated load testing.

[0112] P 热铜 Copper loss during hot load testing;

[0113] P 热铁I Iron loss caused by load current during hot load testing;

[0114] P 热铁 Iron loss caused by the rotor permanent magnet under hot load;

[0115] P 冷铜 =3I 冷 2 R 冷 ;I 冷 For cold load current, R 冷 The resistance is in the cold phase.

[0116] According to the cold load test, P 冷输入 P 冷输出 P 冷铜 P 冷铁 As the results have been obtained, only P is present in the cold-state formula. 冷铁I Unknown, therefore P冷铁I =P 冷输入 -P 冷输出 -P 冷铜 -P 冷铁 =P 冷输入 -P 冷输出 -3I 冷 2 R 冷 -P 冷铁 -P 摩擦 ;

[0117] P 冷铁I The iron loss is caused by the load current, therefore the iron loss per unit current is P9 = P 冷铁I / I 冷 ;

[0118] According to the hot load temperature rise test, when the temperature reaches a stable state, P 热输入 P 冷输出 Given that P 热铜 P is the number that needs to be calculated. 热铁I =P9*I 热 =P 冷铁I / I 冷 *I 热 I 热 P represents the current value when the temperature rise test under hot load stabilizes. 热铁 The iron loss, P, is caused by the rotor permanent magnet when the temperature rise test under hot load stabilizes. 热铁 =P 冷铁 / E 冷 *E 热 E 冷 It is the cold back potential, E 热 E is the hot back potential. 冷 E 热 All of this can be determined through testing.

[0119] According to the above P 热铜 =P 热输入 -P 冷输出 -P 热铁I -P 热铁 -P 摩擦 =P 热输入 -P 冷输出 -P 冷铁I / I 冷 *I 热 -P 冷铁 / E 冷 *E 热 -P 摩擦 ;

[0120] Copper loss P in hot state 热铜 =3*I 热 2 *R tI 热 P 热铜 Given, solve R t .

[0121] R t =P 热铜 / 3 / I 热 2 R t ;

[0122] The winding temperature rise can be calculated using the resistance method temperature rise formula:

[0123] T-T0=(R t -R 冷 ) / R 冷 K;

[0124] The temperature rise test results for windings with mechanical seals are greater than those without because permanent magnet motors need to overcome the friction of the mechanical seal while simultaneously meeting the torque output of the load. The input power in the load test data with mechanical seals is greater than that without mechanical seals, which is consistent with the principle of energy conservation.

[0125] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for controlling the temperature rise of a test winding, characterized in that, Including the following steps: S1. The controller controls the permanent magnet motor under test to perform a no-load test at its rated speed without an mechanical seal, and tests the input power P of the permanent magnet motor under test. 空输入1 and the current I generated under no-load conditions 空1 ; The controller controls the permanent magnet motor under test to perform a no-load test at its rated speed when it is sealed, and the input power P of the permanent magnet motor under test is tested. 空输入2 and the current I generated under no-load conditions 空 2; According to the input power P 空输入1 The copper loss P of the permanent magnet motor under test 空铜损 Iron loss P 空铁损 The sum of, and P 空输入2 The copper loss P of the permanent magnet motor under test 空铜损 Iron loss P 空铁损 and mechanical loss P 摩擦 The sum of these values ​​is used to calculate the copper loss P. 空铜损 Iron loss P 空铁损 Friction and mechanical loss P; S2. Measure the phase resistance R of the permanent magnet motor under static conditions. 冷 ; S3. Drive the permanent magnet motor under test to rotate to a predetermined speed, and when the back electromotive force of the permanent magnet motor under test reaches a stable value, measure the back electromotive force E of the permanent magnet motor under test in the cold state. 冷 ; S4. Cold Load Test: Tests the input power P of the permanent magnet motor under test when it operates at rated power and a predetermined load. 冷入 Output power P 冷出 and input current I 冷 , where P 冷铁I =P 冷入 -P 冷出 -P 冷铜 -P 空铁损 -P 摩擦 ; S5. Hot-state temperature rise test: Adjust the permanent magnet motor under test to operate at the same output power as the permanent magnet motor under test in the cold state in step S4, and monitor the temperature of the casing in real time. When the temperature change of the casing within a preset time is less than a preset value, record the input power P of the permanent magnet motor under test in the hot state at this time. 热入 Output power P 热出 Input current I 热 and the back electromotive force E in the hot state 热 ; where, P 热铁 = P 空铁损 * E 冷 / E 热 ; P 热铁I = P 冷铁I * I 热 / I 冷 ; P 热入 =P 热出 +P 热铜 +P 热铁I +P 热铁 ,P 冷出 =P 热出 ; Calculate P 热铜 =P 热入 -P 冷出 -P 冷铁I *I 热 / I 冷 -P 空铁损 *E 冷 / E 热 -P 摩擦 ; S6, according to R t =P 热铜 / I 热 2 =R 冷 [1+K(T-T0)], calculate △T=T-T0, where R t R is the resistance in the hot state. 冷 Let T be the cold resistance, K be the material constant, T be the hot temperature, and T0 be the cold temperature.

2. The method for controlling the temperature rise of the test winding according to claim 1, characterized in that, In step S1, when the permanent magnet motor under test has no mechanical seal, a no-load test is performed at the rated speed, and the input power P... 空输入1 =P 空铁损 +P 空铜损1 P 摩擦 =0; When the permanent magnet motor under test has an organic seal, a no-load test is performed on the permanent magnet motor under test at its rated speed, wherein P 空输入2 =P 空铁损 +P 空铜损2 +P 摩擦 ; Calculate P 摩擦 =P 空输入2 -P 空输入1 -P 空铜损1 -P 空铜损2 , where P 空铜损1 =P 空铜损2 =0, or P 空铜损1 =3I 空1 2 R, I 空1 P represents the no-load current generated by the tested permanent magnet motor without an inorganic seal. 空铜损2 =3I 空2 2 R, I 空2 The current generated by the tested permanent magnet motor under no-load conditions when it is sealed.

3. The method for controlling the temperature rise of the test winding according to claim 1 or 2, characterized in that, In step S1, the input power of the permanent magnet motor under test is tested using a power measuring instrument.

4. The method for controlling the temperature rise of the test winding according to claim 1 or 2, characterized in that, In step S2, the phase resistance R of the permanent magnet motor under static conditions is measured using a multimeter. 冷 .

5. The method for controlling the temperature rise of the test winding according to claim 1 or 2, characterized in that, In step S4, the back electromotive force E of the permanent magnet motor is measured using a multimeter or power analyzer. 冷 .

6. The method for controlling the temperature rise of the test winding according to claim 1 or 2, characterized in that, The predetermined rotational speed is 1000 r / min.

7. The method for controlling the temperature rise of the test winding according to claim 1 or 2, characterized in that, The preset value is 1K.

8. The method for controlling the temperature rise of the test winding according to claim 1 or 2, characterized in that, The preset time is at least 30 minutes.

9. The method for controlling the temperature rise of the test winding according to claim 1 or 2, characterized in that, In step S5, a thermocouple is installed on the housing of the permanent magnet motor under test, and the thermocouple detects the temperature of the housing in real time.

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