High-speed magnetic suspension bearing loss test platform and test method

Abstract

The invention provides a high-speed magnetic suspension bearing loss test platform and test method, and belongs to the technical field of magnetic suspension bearing performance test. Comprising a vacuum chamber, a supporting unit, a driving unit, a magnetic suspension bearing unit and a measuring unit, the vacuum cabin is used for configuring a vacuum test environment; the supporting unit is used for bearing the driving unit, the magnetic suspension bearing unit and the measuring unit and sending the same into the vacuum cabin; the driving unit is arranged on the end face, away from the ground, of the supporting unit, the movable end of the driving unit is connected with the magnetic suspension bearing unit, and the driving unit is used for transmitting torque to the magnetic suspension bearing unit; and the measuring unit is arranged on the magnetic suspension bearing unit and is used for acquiring detection signals of the vacuum degree, the displacement, the temperature and the rotating speed and evaluating the loss condition of the magnetic suspension bearing unit through a built-in loss separation algorithm, and the loss condition comprises wind friction loss and iron loss and copper loss of an axial magnetic suspension bearing and two radial magnetic suspension bearings.

Description

Technical Field

[0001] This invention relates to the field of magnetic bearing performance testing technology, and in particular to a high-speed magnetic bearing loss testing platform and testing method. Background Technology

[0002] Magnetic bearings, as an advanced support technology characterized by non-contact, frictionless operation, high speed, and high precision, have shown great application potential in high-end equipment fields such as aerospace, high-speed motors, energy and power, and precision machine tools. However, during high-speed rotation, magnetic bearings themselves generate various power losses. These losses not only reduce system efficiency but also lead to bearing temperature rise, directly affecting the rotor's dynamic characteristics and the system's operational stability and reliability. Therefore, accurate measurement, analysis, and separation of the various losses in magnetic bearings are crucial prerequisites for bearing optimization design, performance evaluation, and engineering applications.

[0003] Existing magnetic levitation bearing loss testing methods and devices have many limitations and cannot meet the requirements of high-speed and high-precision testing. These limitations are mainly reflected in the following aspects: 1. The test conditions are singular and cannot simulate the real environment: Traditional tests are usually carried out under normal pressure, which cannot effectively separate and quantify the wind friction loss that dominates at high speed. This results in a significant distortion of the "total loss" measured under normal pressure, failing to accurately reflect the true loss characteristics of the bearing in closed or vacuum environments. Secondly, loss separation is difficult, and measurement accuracy is low. Commonly used copper loss measurements often rely on direct calculation using formulas, neglecting the high-frequency AC copper loss caused by the skin effect and proximity effect. Furthermore, the winding resistance changes with temperature, introducing substantial calculation errors. There is a lack of effective means to measure copper loss online during operation. Thirdly, the iron loss components of magnetic levitation bearings are complex, including rotor and stator iron losses, and are closely related to the bias magnetic field strength. Conventional methods struggle to effectively separate rotor and stator iron losses without shutting down the machine or altering the structure, and further subdivide axial and radial stator iron losses, failing to achieve precise separation of iron loss components. Fourthly, there is a lack of comprehensive testing platforms. Existing test benches have relatively limited functions, often focusing on measuring a single type of loss. There is a lack of a comprehensive experimental platform that integrates vacuum environment simulation and simultaneous monitoring of multiple environmental parameters, leading to cumbersome testing procedures, poor data correlation, and difficulty in comprehensively and systematically evaluating the loss performance of magnetic levitation bearings.

[0004] Therefore, it is essential to provide a high-speed magnetic levitation bearing loss test platform and testing method that can effectively separate and quantify the wind friction loss that dominates at high speeds by providing an adjustable vacuum environment, accurately reflect the real loss characteristics of the bearing in a closed or vacuum application environment, and facilitate the further separation of copper loss and iron loss from the total loss. Summary of the Invention

[0005] In view of this, the present invention proposes a comprehensive testing platform and testing method for high-speed magnetic levitation bearing loss, which can change the vacuum level of the component in which the magnetic levitation bearing under test is located and quantify the wind friction loss through the change in vacuum level.

[0006] On the one hand, the present invention provides a high-speed magnetic levitation bearing loss test platform, including a vacuum chamber, a support unit, a drive unit, a magnetic levitation bearing unit, and a measurement unit; Among them, the vacuum chamber is used to configure a vacuum test environment; A support unit is used to carry the drive unit, magnetic levitation bearing unit, and measurement unit, and to send them into the vacuum chamber; A drive unit is disposed on the end face of the support unit away from the ground. The movable end of the drive unit is connected to the magnetic levitation bearing unit and is used to transmit torque to the magnetic levitation bearing unit. The measurement unit, located in the magnetic levitation bearing unit, is used to acquire detection signals of vacuum degree, displacement, temperature and rotation speed, and also evaluates the wear status of the magnetic levitation bearing unit through a built-in loss separation algorithm.

[0007] Based on the above technical solutions, preferably, the vacuum chamber includes a compartment, one end of which is provided with a fixed door and the other end with a movable door, and the compartment is used to provide a vacuum environment.

[0008] Preferably, the support unit includes two slide rails, a test platform, and a foldable support leg. The two slide rails are arranged parallel and spaced apart in the cabin and extend along a direction parallel to the central axis of the cabin. A foldable support leg is provided at the end of the test platform away from the cabin to maintain the horizontal state of the test platform. Both the foldable support leg and the end of the test platform closer to the cabin are provided with pulleys, which are rolledly connected to the slide rails.

[0009] More preferably, the drive unit includes a motor mounting platform and a drive motor, with the motor mounting platform fixedly connected to the end face of the test bench away from the ground; the drive motor is mounted on the motor mounting platform and fixedly connected to the motor mounting platform.

[0010] More preferably, the magnetic levitation bearing unit includes a main shaft, an axial magnetic levitation bearing, two protective bearings, and two radial magnetic levitation bearings. The main shaft is connected to the output shaft of the drive motor. The axial magnetic levitation bearing is located on the side of the test bench away from the drive motor, and the central axis of the axial magnetic levitation bearing is collinear with the central axis of the main shaft. Two radial magnetic levitation bearings are spaced apart on the main shaft. The two protective bearings are respectively located on the outer side of the non-adjacent end faces of the two radial magnetic levitation bearings and are connected to the test bench. The central axes of the two radial magnetic levitation bearings and the central axes of the two protective bearings are all collinear with the central axis of the main shaft.

[0011] In a further preferred embodiment, the measuring unit includes a vacuum sensor, several displacement sensors, several temperature sensors, and a speed sensor; a vacuum sensor, a speed sensor, a displacement sensor, and several temperature sensors are configured at different positions on the side end face of the axial magnetic levitation bearing; several displacement sensors and several temperature sensors are configured in the circumferential direction of both radial magnetic levitation bearings.

[0012] On the other hand, the present invention also provides a testing method for a high-speed magnetic levitation bearing loss testing platform, comprising the following steps: S0: Configure the high-speed magnetic levitation bearing loss test platform as described above; vacuum sensors, speed sensors, one displacement sensor, and two temperature sensors are configured at different positions on one side end face of the axial magnetic levitation bearing, and one temperature sensor is configured on the other side end face, with the temperature sensor located at the winding of the axial magnetic levitation bearing; four displacement sensors and eight temperature sensors are configured at the circumferential windings of both radial magnetic levitation bearings; start the drive unit and maintain the air gap between the rotor and stator of the axial magnetic levitation bearing and the two radial magnetic levitation bearings at 10-50μm; the measurement unit has a built-in loss separation algorithm; S1: Obtain the total loss under normal pressure; at the target speed. n Below, the total loss is read directly using a dynamometer. P Including wind friction loss P w Iron loss of axial magnetic bearings and two radial magnetic bearings P Fe and copper loss P Cu ; S2: Measuring and separating wind friction loss; first, given atmospheric pressure and a fixed speed. n Total loss at 0 P 0, then the support unit, drive unit, magnetic levitation bearing unit, and measuring unit are sent into the vacuum chamber to change the vacuum level inside the chamber and obtain the result at a fixed rotation speed. n 0 and different vacuum levels p vi = p v1 , p v2 … p vm Total loss P 1, P 2, ..., P m Obtain the reduction in total loss Δ under various vacuum levels. P i Vacuum degree serial number i =1, 2, ..., m and wind friction loss under normal pressureP w0 Based on this, the wind friction loss under various vacuum levels is calculated. The change in total loss is used as the change in wind friction loss at a fixed speed. The change in wind friction loss is fitted with a power function to the vacuum level at a single speed. Then, the speed is changed, and the change in wind friction loss is fitted with a power function to the vacuum level at different speeds to construct an expression for wind friction loss at any speed and vacuum level. S3: Separate DC and AC copper losses; obtain the resistance of each winding of the axial magnetic levitation bearing and the two radial magnetic levitation bearings through heating tests. R tj The active power consumed by each winding is obtained as the total copper loss of each winding, and the effective values ​​of current and voltage for each winding are recorded. The copper loss of each winding includes DC copper loss and AC copper loss; based on the effective values ​​of current and resistance of each winding... R tj Calculate the DC copper loss of each winding; obtain the AC copper loss of each winding from the DC copper loss in the total copper loss of each winding. S4: Separate stator iron loss and rotor iron loss; total iron loss includes rotor iron loss and stator iron loss; by configuring different axial bias currents and radial bias currents, obtain the functions of axial bias current and rotor loss, and the functions of radial bias current and rotor loss under a certain vacuum degree and rotor speed, respectively calculate axial stator iron loss and radial electronic iron loss, add axial electronic iron loss and radial stator iron loss to obtain stator iron loss; subtract the wind friction loss, copper loss and stator iron loss under the current vacuum degree from the total loss under the current vacuum degree to obtain rotor iron loss.

[0013] Preferably, step S2 includes the following: S21: First, at a fixed rotational speed n 0 drives the spindle to run, measuring the total loss under normal pressure. P 0; then maintain a fixed rotation speed. n Keeping the vacuum level constant (0), varying the vacuum level and measuring different vacuum levels. p vi = p v1 , p v2 … p vm Total loss P 1, P 2, ..., P m At this point, the change in total loss is equal to the change in windage loss Δ. P i Fixed speed n Any vacuum degree below 0 p vi The wind friction loss at normal pressurep v0 Corresponding wind friction loss P w0 Subtract △ P i ; to obtain any vacuum degree p vi Wind friction loss and current vacuum level p vi Data pairs constructed from sequence values ​​( p vi , P w ( p vi By fitting the data, we can obtain the results at a fixed rotational speed. n The power function expression under 0; S22: Change the current rotational speed to obtain multiple different rotational speeds. n 1, n 2, ..., n k Repeat step S21 for each rotational speed. n k Each of these yields a corresponding power function expression. By rewriting the power function, we can obtain the wind speed loss under arbitrary vacuum and rotational speed. P w .

[0014] Preferably, in step S3, the resistance of each winding of the axial magnetic levitation bearing and the two radial magnetic levitation bearings is obtained through a heating test. R tj It uses an adjustable DC regulated power supply, a high-precision ammeter, and a high-precision voltmeter to measure the initial temperature. T Apply 10% of the rated current to any winding at 0°C and measure the initial resistance. R 0. Increase the winding current and ensure that the winding temperature change rate is less than 0.5℃ / minute, then record the winding temperature. T and the current voltage of the winding U and current I Calculate the resistance at the current temperature. R t Several temperature resistance data pairs were obtained at different winding temperatures. T , R t The resistance-temperature relationship of the current winding is obtained by fitting the data using the least squares method. Temperature and resistance data pairs are obtained for each winding and fitted using the least squares method to obtain the resistance-temperature relationship of each winding.

[0015] Preferably, in step S4, by configuring different axial and radial bias currents, the functions of axial bias current and rotor loss, and the functions of radial bias current and rotor loss, are obtained under a certain vacuum degree and rotor speed. The axial stator iron loss and radial electronic iron loss are then calculated respectively, and the stator iron loss is obtained by adding the axial electronic iron loss and the radial stator iron loss. This is done under the same rotational speed and the same vacuum degree, given different bias currents. i p The corresponding free deceleration test was conducted to obtain a set of data points ( i p1 , P r1 ), ( i p2 , P r2 ), ... ( i pn , P rn ), P r ={ p r1 , p r2 ... p rn} represents the corresponding total rotor loss, and the total rotor loss is fitted as a power function using data points. P r ( i p The expression for ) is given; then for the axial bias current. i pt and radial bias current i pa By fitting the equation in power function form, the functions of radial bias current with respect to rotor loss are obtained as follows: P r ( i pa and the function of axial bias current with respect to rotor losses. P r ( i pt Setting the radial bias current to 0, the total rotor loss is then obtained. P r ( i pa If =0), then the radial stator iron loss is: P AsFe = P r ( i p )- P r ( i pa=0); Let the axial bias current be 0, then the axial stator iron loss P TsFe = P r ( i p )- P r ( i pt =0); stator iron loss is obtained through addition. P sFe = P AsFe + P TsFe .

[0016] The present invention provides a high-speed magnetic levitation bearing loss testing platform and testing method, which has the following advantages compared with the prior art: 1. By placing a vacuum chamber and multiple temperature sensors on the test platform, the operating status of the bearing can be obtained more synchronously. The vacuum chamber effectively isolates the external environment, and the impact of wind friction loss can be quantified by the change in vacuum degree, thereby improving the measurement accuracy of wind friction loss.

[0017] 2. Further, through heating tests and resistance-temperature relationship fitting, not only DC copper loss was considered, but also AC copper loss caused by factors such as high-frequency harmonics was separated, which is particularly important for bearing design in high-frequency applications.

[0018] 3. By changing the bias current and observing its effect on rotor losses, the axial and radial stator iron losses are calculated separately, ultimately yielding the total stator iron loss and rotor iron loss. This method provides an effective means for a deeper understanding of the distribution of iron losses in magnetic levitation bearings. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a half-section front view of the equipment of the high-speed magnetic levitation bearing loss test platform and test method of the present invention. Figure 2 This is a schematic diagram of the vacuum chamber of a high-speed magnetic levitation bearing loss test platform and test method according to the present invention; Figure 3 This is a schematic diagram of the support unit of a high-speed magnetic levitation bearing loss test platform and test method according to the present invention; Figure 4 This is a schematic diagram of the combined state of the magnetic levitation bearing unit and the measurement unit in the high-speed magnetic levitation bearing loss test platform and test method of the present invention. Figure 5 This is a flowchart of the loss separation algorithm of a high-speed magnetic levitation bearing loss test platform and test method according to the present invention; Figure 6 is a flowchart of the measurement and fitting of wind friction loss of a high-speed magnetic levitation bearing loss test platform and test method of the present invention. Figure 7 This is a flowchart illustrating the measurement and separation of copper loss in a high-speed magnetic levitation bearing loss test platform and testing method according to the present invention. Figure 8 This is a flowchart illustrating the measurement and separation of iron loss in a high-speed magnetic levitation bearing loss test platform and testing method according to the present invention. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] Some methods and devices for testing the losses of magnetic levitation bearings have many limitations, making it difficult to meet the requirements of high-speed and high-precision testing. For example, the test conditions are singular and cannot simulate the real environment: traditional tests are usually carried out under normal pressure, which cannot effectively separate and quantify the wind friction loss that dominates at high speeds; commonly used copper loss measurements are mostly calculated directly using formulas, but they ignore the high-frequency AC copper loss caused by the skin effect and proximity effect, and the winding resistance changes with temperature, introducing a large calculation error; the iron loss components of magnetic levitation bearings are complex, including rotor iron loss and stator iron loss, and are closely related to the bias magnetic field strength. Conventional methods are difficult to effectively separate rotor iron loss and stator iron loss without stopping the machine or changing the structure; existing test benches have relatively simple functions, often focusing on the measurement of a certain type of loss, and lack a comprehensive experimental platform that integrates vacuum environment simulation and simultaneous monitoring of multiple environmental parameters.

[0023] In view of this, such as Figure 1 As shown, on one hand, the present invention provides a high-speed magnetic levitation bearing loss test platform, including a vacuum chamber, a support unit, a drive unit, a magnetic levitation bearing unit, and a measurement unit; The vacuum chamber is used to configure a vacuum test environment; the vacuum level inside the vacuum chamber is adjustable to simulate the effects of wind friction loss under different vacuum levels. A support unit is used to carry the drive unit, magnetic levitation bearing unit, and measurement unit, and to send them into the vacuum chamber; A drive unit is disposed on the end face of the support unit away from the ground. The movable end of the drive unit is connected to the magnetic levitation bearing unit and is used to transmit torque to the magnetic levitation bearing unit. The measurement unit, located in the magnetic levitation bearing unit, is used to acquire detection signals of vacuum degree, displacement, temperature and rotation speed, and also evaluates the wear status of the magnetic levitation bearing unit through a built-in loss separation algorithm.

[0024] The aforementioned high-speed magnetic levitation bearing loss test platform has a reasonable structure and high integration. It can be used for the performance verification of high-speed magnetic levitation bearings, and can reliably separate and calculate wind friction loss, copper loss and iron loss. It has high measurement accuracy and a wide range of applications.

[0025] like Figure 1 and Figure 2 As shown, the vacuum chamber includes a chamber 2, with a fixed door 1 at one end and a movable door 8 at the other end. The chamber 1 provides a vacuum environment. The chamber 2 is a cylindrical cavity structure. The fixed door 1 is bolted to the chamber 2 and has a connection port for connecting to a vacuum pump. The movable door 8 is movably connected to the chamber 2 via a cylindrical pin, forming an openable passage. In a preferred embodiment, symmetrical support legs are provided on both sides of the chamber 2 to maintain the stability of the chamber 2's attitude and position.

[0026] like Figure 3 As shown, the support unit includes two slide rails 3, a test bench 7, and foldable support legs 23. The two slide rails 3 are arranged parallel and spaced apart inside the chamber 2, extending along a direction parallel to the central axis of the chamber 2. The foldable support legs 23 are provided at the end of the test bench 7 away from the chamber to maintain the horizontal state of the test bench 7. Both the foldable support legs 23 and the end of the test bench 7 near the chamber are provided with pulleys 4, which are rolledly connected to the slide rails 3. The extending direction of the two slide rails 3 is parallel to the axis of the chamber 2.

[0027] Since the test bench 7 is always inserted into the chamber 2 at one end first, a foldable support leg 23 is only provided at one end. The foldable support leg 23 in the stored state can ensure that the test bench 7 is level. The pulley 4 is connected to the slide rail 3 in a rolling manner, which can ensure that the support unit can be smoothly put into or removed from the chamber 2.

[0028] Similarly, Figure 1 As shown, the drive unit includes a motor mounting platform 5 and a drive motor 6. The motor mounting platform 5 is fixedly connected to the end face of the test bench 7 that is away from the ground. The drive motor 6 is mounted on the motor mounting platform 5 and fixedly connected to it. The drive motor is used to drive the magnetic levitation bearing unit to rotate. The drive motor 6 and the motor mounting platform 5 are connected by bolts.

[0029] like Figure 4 As shown, the magnetic levitation bearing unit includes a main shaft 10, an axial magnetic levitation bearing 18, two protective bearings, and two radial magnetic levitation bearings. The main shaft 10 is connected to the output shaft of the drive motor 6. The axial magnetic levitation bearing 18 is located on the side of the test bench 7 away from the drive motor 6, and the central axis of the axial magnetic levitation bearing 18 is collinear with the central axis of the main shaft 10. Two radial magnetic levitation bearings are spaced apart on the main shaft 10, i.e. Figure 1 Marks 11 and 13 in the figure are the first radial magnetic levitation bearing and the second radial magnetic levitation bearing, respectively; the two protective bearings are the first protective bearing and the second protective bearing, namely marks 9 and 15 in the figure, which are respectively set on the outer side of the non-adjacent end faces of the two radial magnetic levitation bearings and connected to the test bench 7. The central axes of the two radial magnetic levitation bearings and the central axes of the two protective bearings are all collinear with the central axis of the main shaft 10.

[0030] The measurement unit includes a vacuum sensor 22, several displacement sensors, several temperature sensors, and a speed sensor 21. Vacuum sensors 22, speed sensors 21, one displacement sensor, and several temperature sensors are configured at different positions on the side end face of the axial magnetic bearing 18. Several displacement sensors and several temperature sensors are configured along the circumference of both radial magnetic bearings. In this embodiment, a total of nine displacement sensors, 19 temperature sensors, one vacuum sensor, and one speed sensor are configured to acquire relevant operating parameters of the axial magnetic bearing 18 and the two radial magnetic bearings, thereby providing data support for the loss separation algorithm.

[0031] In addition, such as Figure 5 As shown, the present invention also provides a testing method for a high-speed magnetic levitation bearing loss testing platform, comprising the following steps: S0: Configure the high-speed magnetic levitation bearing loss test platform described above; vacuum sensors 22, speed sensors 21, first displacement sensors 20, first temperature sensors 16, and second temperature sensors 18 are arranged at different positions on one side end face of the axial magnetic levitation bearing 18, and a third temperature sensor 19 is arranged on the other side end face. The temperature sensors are located at the winding of the axial magnetic levitation bearing 18; four second displacement sensors 14 and eight fourth temperature sensors 12 are arranged at the circumferential winding of the first radial magnetic levitation bearing 11; four second displacement sensors 14 and eight fourth temperature sensors 12 are also arranged at the circumferential winding of the second radial magnetic levitation bearing 13. Start the drive unit and maintain the air gap between the rotor and stator of the axial magnetic levitation bearing and the two radial magnetic levitation bearings at 10-50μm; the measurement unit has a built-in loss separation algorithm.

[0032] S1: Obtain the total loss under normal pressure; at the target speed. n Below, the total loss is read directly using a dynamometer.P Including wind friction loss P w Iron loss of axial magnetic bearings and two radial magnetic bearings P Fe and copper loss P Cu Total loss P Its composition is as follows: Total loss P The reading can be obtained directly from the dynamometer at the stator power supply.

[0033] S2: Measuring and separating wind friction loss; first, given atmospheric pressure and a fixed speed. n Total loss at 0 P 0, then the support unit, drive unit, magnetic levitation bearing unit, and measuring unit are sent into the vacuum chamber to change the vacuum level inside the chamber and obtain the result at a fixed rotation speed. n 0 and different vacuum levels p vi = p v1 , p v2 … p vm Total loss P 1, P 2, ..., P m Obtain the reduction in total loss Δ under various vacuum levels. P i , i =1, 2, ..., m and wind friction loss under normal pressure P w0 Based on this, wind friction loss is calculated at various vacuum levels. The change in total loss is used as the change in wind friction loss at a fixed speed. The change in wind friction loss is fitted with a power function to the vacuum level at a single speed. Then, the speed is changed, and the power function fitting is repeated for the change in wind friction loss and vacuum level at different speeds to construct an expression for wind friction loss at any speed and vacuum level.

[0034] Wind friction loss P w The main cause is that when the rotor rotates at high speed, it undergoes viscous friction with the surrounding air, which also generates eddies and wakes. The higher the speed, the more obvious the loss.

[0035] like Figure 6 As shown, step S2 includes the following: S21: First, at a fixed speed n 0 drives the spindle to run, measuring the total loss under normal pressure. P 0; then maintain a fixed rotation speed. nKeeping the vacuum level constant (0), varying the vacuum level and measuring different vacuum levels. p vi = p v1 , p v2 … p vm Total loss P 1, P 2, ..., P m subscript i The vacuum degree sequence number is used. At this point, the change in total loss equals the change in windage loss. A constant rotational speed is fitted. n Wind friction loss expression at 0 P w ( p vi , n 0).

[0036] Here, the vacuum gauge reading is observed when it remains essentially constant for half a minute, with fluctuations not exceeding 10 Pa. The maximum value is recorded as the current vacuum level. p v sequence values p v1 , p v2 , ..., p vm For example, 20000Pa, 10000Pa, 5000Pa, ...; obtain the total loss under the corresponding vacuum level. P 1, P 2, ..., P m Assuming normal pressure p v0 Corresponding wind friction loss P w0 =△ P max Since iron loss and copper loss remain essentially constant under constant rotational speed and magnetic field conditions, the reduction in total loss is equivalent to the reduction in windage loss Δ. P i = P 0- P i , P 0 represents a fixed rotational speed. n Total losses measured at 0 and normal pressure. P i The total loss is calculated under different vacuum levels. i =1,2,..., m At a fixed speed n Any vacuum degree below 0 p viThe expression for wind friction loss is as follows: P w ( p vi )= P w0 -△ P i ; to obtain any vacuum degree p vi Wind friction loss and current vacuum level p vi Data pairs constructed from sequence values ​​( p vi , P w ( p vi By fitting the data, we can obtain the results at a fixed rotational speed. n The expression for the power function under 0: P w ( p v， n 0)= K n0 ×( p v ) b , K n0 For the fitting coefficients, b This is the exponential term.

[0037] S22: Then change the speed, such as 80,000 rpm, 60,000 rpm, ... for each speed. n k A set of fitting coefficients was obtained for each. K nk The data pairs consisting of rotational speed and fitting coefficients ( n k , K nk Power function fitting is performed to construct the final expression for wind friction loss.

[0038] Change the current rotational speed and repeat step S21 to obtain multiple different rotational speeds. n 1, n 2, ..., n k The rotational speed here is obtained through a speed sensor. When the rotational speed reaches the target value and the fluctuation range does not exceed 5 rpm, the speed is considered stable. For each rotational speed... n k All can get the corresponding k Group fitting coefficients K nk and exponential terms b kTake the average of multiple exponential terms. , the fitting coefficient term K nk Rewritten as rotational speed n The power function is obtained K nk = K'•n c ; K’ For coefficient terms, c A general variable for the current rotational speed n The exponential term; combining the contents of steps S21 and S22, we obtain the final expression for wind friction loss: This expression allows us to obtain the windage loss at any vacuum level and rotational speed. P w This allows wind friction loss to be separated from total loss.

[0039] S3: Separate DC and AC copper losses; obtain the resistance of each winding of the axial magnetic levitation bearing and the two radial magnetic levitation bearings through heating tests. R tj The active power consumed by each winding is obtained as the total copper loss of each winding, and the effective values ​​of current and voltage for each winding are recorded. The copper loss of each winding includes DC copper loss and AC copper loss; based on the effective values ​​of current and resistance of each winding... R tj Calculate the DC copper loss of each winding; from the DC copper loss in the total copper loss of each winding, obtain the AC copper loss of each winding.

[0040] The heating test consisted of the following steps: using an adjustable DC regulated power supply, a high-precision ammeter, and a high-precision voltmeter, at the initial temperature... T At 0 degrees Celsius, at the initial temperature T When a very small DC current, such as 10% of the rated current, is applied to any winding at 0°C, the initial resistance at the reference temperature is measured as follows: R 0; then slowly increase the DC current, allowing the coil to heat up spontaneously through the Joule effect. To ensure safety, set the absolute upper limit of the winding temperature to 125℃; stop increasing the current when the temperature reaches 120℃. Ensure the winding temperature change rate is less than 0.5℃ / minute before measuring the winding temperature. T and the current voltage of the winding U and current I Calculate the resistance at the current temperature. R t = U / I Several temperature resistance data pairs were obtained at different winding temperatures. T , R tBy fitting the data using the least squares method, the resistance-temperature relationship of the current winding is obtained. ,in α is the temperature coefficient of resistance.

[0041] For other windings, repeat the above measurement process and fit similar resistance-temperature relationships. Then, write all the resistance-temperature relationships uniformly as follows: subscript j Indicates the first j One winding, T j , T 0j The first j The current temperature and reference temperature of each winding.

[0042] Measurement method of copper loss of magnetic levitation bearing: (1) Connect the positive and negative input terminals of the high voltage differential probe directly to the two leads of each winding. Clamp the current probe to one lead of the winding and ensure that the direction is correct; (2) Start the magnetic levitation bearing and drive unit to make the main shaft and the rotor of the magnetic levitation bearing reach the target speed and run stably; (3) Read and record the total active power consumed by each winding directly from the power analyzer. P total1 , P total2 … P total19 The total active power corresponds to the copper loss of each winding. P Cu1 , P Cu2 … P Cu19 Simultaneously record the effective current value of each winding. I 1. I 2、…、 I 19 RMS voltage U 1. U 2、…、 U 19 and temperature T 1. T 2、…、 T 19 The total copper loss of the axial magnetic bearing and the two radial magnetic bearings is P Cu = P dc + P ac = P Cu1 + P Cu2 +…+ PCu19 ; P dc , P ac These are DC copper loss and AC copper loss, respectively. AC copper loss refers to the additional power loss generated when a conductor carries alternating current, due to various physical effects that increase its actual resistance. The main causes include the skin effect and losses caused by high-frequency currents.

[0043] DC copper loss is calculated using the following formula: , I j The effective current value for each winding, R tj For the first j The resistance of each winding at the current temperature, after expansion, is as follows: DC copper loss AC copper loss This enables the separate measurement of DC copper loss and AC copper loss in copper loss.

[0044] S4: Separate stator iron loss and rotor iron loss; total iron loss includes rotor iron loss and stator iron loss; by configuring different axial bias currents and radial bias currents, obtain the functions of axial bias current and rotor loss, and the functions of radial bias current and rotor loss under a certain vacuum degree and rotor speed, respectively calculate axial stator iron loss and radial electronic iron loss, add axial electronic iron loss and radial stator iron loss to obtain stator iron loss; subtract the wind friction loss, copper loss and stator iron loss under the current vacuum degree from the total loss under the current vacuum degree to obtain rotor iron loss.

[0045] Specifically, by configuring different axial and radial bias currents, the functions of axial bias current and rotor loss, as well as the functions of radial bias current and rotor loss, are obtained under a certain vacuum degree and rotor speed. The axial stator iron loss and radial electronic iron loss are then calculated separately. The stator iron loss is obtained by adding the axial electronic iron loss and the radial stator iron loss, given at the same speed and vacuum degree with different bias currents. i p The corresponding free deceleration test was conducted to obtain a set of data points ( i p1 , P r1 ), ( i p2 , P r2 ), ... ( i pn , P rn ), P r ={ p r1 ,p r2 ... p rn} represents the corresponding total rotor loss, and the total rotor loss is fitted as a power function using data points. P r ( i p The expression for ) is given; then for the axial bias current. i pt and radial bias current i pa By fitting the equation in power function form, the functions of radial bias current with respect to rotor loss are obtained as follows: P r ( i pa and the function of axial bias current with respect to rotor losses. P r ( i pt Setting the radial bias current to 0, the total rotor loss is then obtained. P r ( i pa If =0), then the radial stator iron loss is: P AsFe = P r ( i p )- P r ( i pa =0); Let the axial bias current be 0, then the axial stator iron loss P TsFe = P r ( i p )- P r ( i pt =0); stator iron loss is obtained through addition. P sFe = P AsFe + P TsFe .

[0046] The specific analysis process is as follows: Iron loss is measured through a free deceleration test, under a vacuum degree of [missing information]. p v In an environment where the motor power is cut off, the time it takes for the rotor to decrease from one speed to another is recorded. At this point, the rotor's kinetic energy is converted into losses, and the total rotor loss is... , PFe For the iron loss of axial magnetic bearings and two radial magnetic bearings, P m For the losses of the drive motor; P w The wind friction loss under the current vacuum level is obtained through the final wind friction loss expression in step S2; the angular velocity of free deceleration. , n The average speed for free deceleration has a fluctuation range of <±5 rpm. Iron loss. P Fe Including rotor iron loss P rFe and stator iron loss P sFe , Among them, stator iron loss P sFe Including axial stator iron loss P TsFe and radial stator iron loss P AsFe , .

[0047] The iron loss of axial magnetic bearings and two radial magnetic bearings is caused by bias current. i p Theoretically, when the radial bias current is determined... i pa and axial bias current i pt When both are 0, the total rotor loss is Due to bias current i p Since magnetic levitation bearings cannot reach a zero-loss state during operation, it is necessary to set the total rotor loss under different radial and axial bias currents. P r The total rotor loss was obtained by fitting. The value of .

[0048] The specific fitting process is as follows: 1. Under the same rotational speed and vacuum level, the rotational speed fluctuation range is <±5 rpm, and the vacuum pressure change is <±10 Pa.

[0049] 2. Obtain a set of data points Subsequently, a power function of the bias current was fitted to the total rotor loss. , obtain parameters a , e and k For axial bias current i pt and radial bias current i paBy fitting the data, the function of axial bias current with respect to rotor losses is obtained. and the radial bias current as a function of rotor losses. , a t , a a For parameter items, e t , e a This is a bias term.

[0050] Let the radial bias current i pa The value is 0A, at which point the total rotor loss is 0A. Therefore, the radial stator iron loss is Set the axial bias current. i pt The value is 0A. At this point, the total rotor loss is 0A, so the axial stator iron loss is 0A. Therefore, the stator iron loss is .

[0051] Since the total loss has already been obtained P Current wind wear loss P w The total copper loss of the axial magnetic bearing and the two radial magnetic bearings. P Cu Stator iron loss P sFe In this case, the rotor's iron loss is This achieves the separation of stator iron losses and rotor iron losses.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-speed magnetic levitation bearing loss testing platform, characterized in that, It includes a vacuum chamber, a support unit, a drive unit, a magnetic levitation bearing unit, and a measurement unit; The vacuum chamber is used to configure a vacuum testing environment; The support unit is used to carry the drive unit, the magnetic levitation bearing unit, and the measuring unit, and to send them into the vacuum chamber; The drive unit is disposed on the end face of the support unit away from the ground, and the movable end of the drive unit is connected to the magnetic levitation bearing unit for transmitting torque to the magnetic levitation bearing unit. The measurement unit, located in the magnetic levitation bearing unit, is used to acquire detection signals of vacuum degree, displacement, temperature and rotation speed, and also evaluates the wear status of the magnetic levitation bearing unit through a built-in loss separation algorithm.

2. The high-speed magnetic levitation bearing loss test platform according to claim 1, characterized in that, The vacuum chamber includes a compartment, with a fixed door at one end and a movable door at the other end. The compartment is used to provide a vacuum environment.

3. The high-speed magnetic levitation bearing loss test platform according to claim 2, characterized in that, The support unit includes two slide rails, a test bench, and a foldable support leg. The two slide rails are arranged parallel to each other and spaced apart in the cabin, and extend along a direction parallel to the central axis of the cabin. The end of the test bench away from the cabin is provided with a foldable support leg to maintain the horizontal state of the test bench. Both the foldable support leg and the end of the test bench closer to the cabin are provided with pulleys, which are rolledly connected to the slide rails.

4. The high-speed magnetic levitation bearing loss test platform according to claim 3, characterized in that, The drive unit includes a motor mounting platform and a drive motor. The motor mounting platform is fixedly connected to the end face of the test bench away from the ground. The drive motor is mounted on the motor mounting platform and fixedly connected to the motor mounting platform.

5. The high-speed magnetic levitation bearing loss test platform according to claim 4, characterized in that, The magnetic levitation bearing unit includes a main shaft, an axial magnetic levitation bearing, two protective bearings, and two radial magnetic levitation bearings. The main shaft is connected to the output shaft of the drive motor. The axial magnetic levitation bearing is located on the side of the test bench away from the drive motor, and the central axis of the axial magnetic levitation bearing is collinear with the central axis of the main shaft. Two radial magnetic levitation bearings are spaced apart on the main shaft. The two protective bearings are respectively located on the outer side of the non-adjacent end faces of the two radial magnetic levitation bearings and are connected to the test bench. The central axes of the two radial magnetic levitation bearings and the central axes of the two protective bearings are all collinear with the central axis of the main shaft.

6. The high-speed magnetic levitation bearing loss test platform according to claim 5, characterized in that, The measuring unit includes a vacuum sensor, several displacement sensors, several temperature sensors, and a speed sensor; a vacuum sensor, a speed sensor, a displacement sensor, and several temperature sensors are arranged at different positions on the side end face of the axial magnetic levitation bearing; several displacement sensors and several temperature sensors are arranged in the circumferential direction of both radial magnetic levitation bearings.

7. A test method for a high-speed magnetic levitation bearing loss test platform, characterized in that, Includes the following steps: S0: Configure the high-speed magnetic levitation bearing loss test platform as described in claim 5 or 6; a vacuum sensor, a speed sensor, a displacement sensor, and two temperature sensors are configured at different positions on one side end face of the axial magnetic levitation bearing, and a temperature sensor is configured on the other side end face, with the temperature sensor located at the winding of the axial magnetic levitation bearing; four displacement sensors and eight temperature sensors are configured at the circumferential windings of the two radial magnetic levitation bearings; start the drive unit and maintain the air gap between the rotor and stator of the axial magnetic levitation bearing and the two radial magnetic levitation bearings at 10-50μm; the measurement unit has a built-in loss separation algorithm; S1: Obtain the total loss under normal pressure; at the target speed. n Below, the total loss is read directly using a dynamometer. P Including wind friction loss P w Iron loss of axial magnetic bearings and two radial magnetic bearings P Fe and copper loss P Cu ; S2: Measuring and separating wind friction loss; first, given atmospheric pressure and a fixed speed. n Total loss at 0 P 0, then the support unit, drive unit, magnetic levitation bearing unit, and measuring unit are sent into the vacuum chamber to change the vacuum level inside the chamber and obtain the result at a fixed rotation speed. n 0 and different vacuum levels p vi = p v1 , p v2 … p vm Total loss P 1, P 2, ..., P m Obtain the reduction in total loss Δ under various vacuum levels. P i Vacuum degree serial number i =1, 2, ..., m and wind friction loss under normal pressure P w0 Based on this, the wind friction loss under various vacuum levels is calculated. The change in total loss is used as the change in wind friction loss at a fixed speed. The change in wind friction loss is fitted with a power function to the vacuum level at a single speed. Then, the speed is changed, and the change in wind friction loss is fitted with a power function to the vacuum level at different speeds to construct an expression for wind friction loss at any speed and vacuum level. S3: Separate DC and AC copper losses; obtain the resistance of each winding of the axial magnetic bearing and the two radial magnetic bearings through heating tests. R tj The active power consumed by each winding is obtained as the total copper loss of each winding, and the effective values ​​of current and voltage for each winding are recorded. The copper loss of each winding includes DC copper loss and AC copper loss; based on the effective values ​​of current and resistance of each winding... R tj Calculate the DC copper loss of each winding; obtain the AC copper loss of each winding from the DC copper loss in the total copper loss of each winding. S4: Separate stator iron loss and rotor iron loss; total iron loss includes rotor iron loss and stator iron loss; by configuring different axial bias currents and radial bias currents, obtain the functions of axial bias current and rotor loss, and the functions of radial bias current and rotor loss under a certain vacuum degree and rotor speed, respectively calculate axial stator iron loss and radial electronic iron loss, add axial electronic iron loss and radial stator iron loss to obtain stator iron loss; subtract the wind friction loss, copper loss and stator iron loss under the current vacuum degree from the total loss under the current vacuum degree to obtain rotor iron loss.

8. The testing method for a high-speed magnetic levitation bearing loss testing platform according to claim 7, characterized in that, Step S2 includes the following: S21: First, at a fixed rotational speed n 0 drives the spindle to run, measuring the total loss under normal pressure. P 0; then maintain a fixed rotation speed. n Keeping the vacuum level constant (0), varying the vacuum level and measuring different vacuum levels. p vi = p v1 , p v2 … p vm Total loss P 1, P 2, ..., P m At this point, the change in total loss is equal to the change in windage loss Δ. P i Fixed speed n Any vacuum degree below 0 p vi The wind friction loss at normal pressure p v0 Corresponding wind friction loss P w0 Subtract △ P i ; to obtain any vacuum degree p vi Wind friction loss and current vacuum level p vi Data pairs constructed from sequence values ​​( p vi , P w ( p vi By fitting the data, we can obtain the results at a fixed rotational speed. n The power function expression under 0; S22: Change the current rotational speed to obtain multiple different rotational speeds. n 1, n 2, ..., n k Repeat step S21 for each rotational speed. n k Each of these yields a corresponding power function expression. By rewriting the power function, we can obtain the wind speed loss under arbitrary vacuum and rotational speed. P w .

9. The testing method for a high-speed magnetic levitation bearing loss testing platform according to claim 7, characterized in that, Step S3 involves obtaining the resistance of each winding of the axial magnetic levitation bearing and the two radial magnetic levitation bearings through a heating test. R tj It uses an adjustable DC regulated power supply, a high-precision ammeter, and a high-precision voltmeter to measure the initial temperature. T Apply 10% of the rated current to any winding at 0°C and measure the initial resistance. R 0. Increase the winding current and ensure that the winding temperature change rate is less than 0.5℃ / minute, then record the winding temperature. T and the current voltage of the winding U and current I Calculate the resistance at the current temperature. R t Several temperature resistance data pairs were obtained at different winding temperatures. T , R t The resistance-temperature relationship of the current winding is obtained by fitting the data using the least squares method. Temperature and resistance data pairs are obtained for each winding and fitted using the least squares method to obtain the resistance-temperature relationship of each winding.

10. The testing method for a high-speed magnetic levitation bearing loss testing platform according to claim 7, characterized in that, Step S4 describes obtaining the functions of axial bias current and rotor loss, as well as radial bias current and rotor loss, under a certain vacuum degree and rotor speed by configuring different axial and radial bias currents. The axial stator iron loss and radial electronic iron loss are then calculated, and the stator iron loss is obtained by adding the axial electronic iron loss and radial stator iron loss. This process is performed under the same rotational speed and vacuum degree, given different bias currents. i p The corresponding free deceleration test was conducted to obtain a set of data points ( i p1 , P r1 ), ( i p2 , P r2 ), ... ( i pn , P rn ), P r ={ p r1 , p r2 ... p rn } represents the corresponding total rotor loss, and the total rotor loss is fitted as a power function using data points. P r ( i p The expression for ) is given; then for the axial bias current. i pt and radial bias current i pa By fitting the equations in power function form, the functions of radial bias current with respect to rotor loss are obtained as follows: P r ( i pa and the function of axial bias current with respect to rotor losses. P r ( i pt Setting the radial bias current to 0, the total rotor loss is then obtained. P r ( i pa If =0), then the radial stator iron loss is: P AsFe = P r ( i p )- P r ( i pa =0); Let the axial bias current be 0, then the axial stator iron loss P TsFe = P r ( i p )- P r ( i pt =0); stator iron loss is obtained through addition. P sFe = P AsFe + P TsFe .

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