Method and system for suppressing wind friction loss of high-voltage magnetic suspension motor

Abstract

The invention relates to a wind friction loss suppression method for a high-voltage magnetic suspension motor, and the method comprises the steps: collecting three-phase input voltage, current, active power and reactive power, correcting the copper loss in real time, and calculating the constant loss Pcon of the motor; measuring a wind friction torque Tfw and a mechanical friction torque Tme in a normal pressure and vacuum environment, and converting wind friction loss Pfw and mechanical friction loss Pme; the no-load iron loss PFe is calculated through the formula PFe = Pcon-Pfw-Pme; and based on a coupling correlation curve of PFe and Pfw, the suspension air gap length delta of the magnetic suspension bearing and the axial speed v of cooling air are adjusted, and wind friction loss is restrained. Through the integrated suppression method, wind friction loss and mechanical friction loss are accurately separated, the loss evaluation accuracy is improved, the suspension air gap length, the rotor surface roughness and the cooling air speed are cooperatively optimized, systematic suppression of the wind friction loss is achieved, the loss and temperature rise are remarkably reduced, the operation efficiency and reliability of the motor are improved, and the method has engineering application value.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of magnetic levitation motors, in particular to a high-voltage magnetic levitation motor wind friction loss suppression method and system. BACKGROUND

[0002] High-voltage magnetic levitation motors have become an important development direction of modern high-end equipment power systems due to their outstanding characteristics of non-contact support, high-speed capability, high power density, high efficiency, and almost maintenance-free. The voltage range of high-voltage magnetic levitation motors is usually between 1kV and 6kV, which covers a variety of high-power application scenarios. In the field of aerospace, it is widely used in flywheel energy storage, turbomolecular pumps, and aircraft engine starting and generating systems, significantly improving the energy utilization efficiency and reliability of the system; in industrial automation, high-speed centrifugal compressors, CNC machine tool spindles, and other equipment achieve more stable and accurate operation with the help of magnetic levitation motors; in emerging energy conversion systems such as new energy power generation, energy storage systems, and hydrogen energy equipment, high-voltage magnetic levitation motors also show great application potential. Since the rotor is suspended in the air gap during operation, mechanical friction of traditional bearings is avoided, and theoretically, it can achieve infinite life operation, which further promotes its popularity in high-reliability scenarios.

[0003] However, as the motor continues to develop towards higher power density and higher speed, especially with the increasing voltage level, the electromagnetic, thermal, and fluid multi-physical field coupling effects inside the motor become more and more significant, and the wind friction loss problem is increasingly prominent. Wind friction loss is mainly caused by the viscous shear effect between the high-speed rotating rotor and the surrounding cooling gas (usually air or hydrogen), which is proportional to the third power or even higher power of the rotor surface speed, so it grows exponentially under super-speed working conditions. This loss not only directly converts into heat, causing the rotor body temperature to rise sharply, but also can trigger a chain reaction of thermal deformation, material performance degradation, and even magnetic suspension system instability. Especially in a high-pressure sealed environment, the increased gas density further exacerbates the gas friction effect, while the limited heat dissipation channel makes it difficult to effectively remove heat, forming a vicious cycle of "high loss-high temperature rise-low reliability". Therefore, how to effectively identify, accurately measure, and systematically suppress wind friction loss has become a core technical problem that needs to be broken through in the current high-voltage magnetic levitation motor design and control, and is directly related to whether the motor can achieve long-term, efficient, and safe stable operation.

[0004] From the perspective of control strategy, most current methods rely on empirical formulas or simple feedback mechanisms, lacking precise perception of operating state and dynamic response capability. When the motor is in complex working conditions such as variable speed, variable load or environmental temperature fluctuation, it is difficult for such control strategies to adjust parameters in real time to maintain optimal operating state, resulting in unstable wind friction loss suppression effect and poor adaptability. A kind of magnetic suspension blower and magnetic suspension compressor (publication number CN119042144A) mentions the influence of air duct area on wind friction loss. When St is too large, the performance will be reduced and the wind friction loss will be increased.

[0005] Although some research has made some progress in the suppression of wind friction loss, the overall technology still faces core challenges such as systematic deficiencies and poor dynamic adaptability. Specifically, existing methods focus on local optimization of a single factor, lack comprehensive consideration of the coupling relationship between motor structure, thermal management and control system, and are difficult to achieve global optimal control of wind friction loss. At the same time, due to the lack of high-precision loss separation measurement technology, wind friction loss and mechanical friction loss are often difficult to accurately distinguish, which directly affects the accuracy of loss evaluation and further weakens the effectiveness and credibility of the suppression strategy. SUMMARY

[0006] The purpose of the present application is to overcome the deficiencies of the prior art and provide a high-voltage magnetic suspension motor wind friction loss suppression method and system, which breaks through the limitations of traditional single-point optimization and achieves comprehensive suppression of wind friction loss.

[0007] The purpose of the present application is achieved by the following technical solutions:

[0008] A high-voltage magnetic suspension motor wind friction loss suppression method, comprising the following steps:

[0009] Collecting three-phase input voltage, current, active power and reactive power, and correcting copper loss in real time according to motor phase number, line resistance and temperature coefficient to calculate motor constant loss Pcon;

[0010] Using active magnetic suspension bearing to non-contact sleeve the power output shaft of the test driving device on the rotor, measuring the wind friction torque Tfw and the corresponding speed n in the normal pressure air environment, and converting to obtain the wind friction loss Pfw;

[0011] Switching the cabin to an environment with a vacuum degree better than 10-2P a , keeping the same speed n, measuring the mechanical friction torque Tme and converting to obtain the mechanical friction loss Pme;

[0012] According to the law of conservation of energy, the no-load iron loss PFe of the high-voltage magnetic suspension motor is calculated by the formula PFe=Pcon-Pfw-Pme;

[0013] Based on the coupling correlation curve of PFe and Pfw, the suspension air gap length δ of the magnetic suspension bearing and the axial speed v of the cooling wind are adjusted to suppress the wind friction loss.

[0014] The method accurately separates the wind friction loss and the mechanical friction loss by comparing tests in normal pressure and high vacuum environments, combined with high-precision torque and speed measurement; calculates the no-load iron loss by energy conservation, and establishes the coupling relationship between the iron loss and the wind friction loss; on this basis, the suspension air gap, the rotor surface roughness and the cooling wind speed are adjusted to realize precise suppression of the wind friction loss.

[0015] As a preferred mode, in a normal pressure environment, the net torque Tfw required by the motor output is recorded, and the real-time speed n of the rotor is measured by using an optical encoder, and the wind friction loss is calculated by the formula Pfw=2π·Tfw·n / 60.

[0016] As a preferred mode, under the same speed n, the rotor is placed in a vacuum chamber to exclude air resistance, and the residual mechanical friction torque Tme is measured, and the mechanical friction loss is obtained by the formula Pme=2π·Tme·n / 60.

[0017] As a preferred mode, under the same supply voltage, frequency and winding temperature conditions, the measured motor constant loss Pcon is deducted from the measured wind friction loss Pfw and mechanical friction loss Pme, and the formula PFe=Pcon-Pfw-Pme is used to obtain the no-load iron loss of the high-pressure magnetic suspension motor as the reference value for the subsequent suppression strategy.

[0018] As a preferred mode, in the range of 3mm≤δ≤8mm, the suspension position of the magnetic suspension bearing is changed, the trend of the wind friction loss decreasing exponentially with the increase of δ is monitored, and the optimal δ value is selected to achieve the maximum loss reduction.

[0019] As a preferred mode, the roughness Ra of the outer surface of the rotor is adjusted, a carbon fiber sleeve treated by multiple mirror polishing processes is applied to the outer surface of the rotor, so that the surface roughness Ra is controlled in the range of 0.4μm≤Ra≤1.6μm, and an online roughness detector is used to monitor the change of Ra, and the polishing is performed again if necessary to maintain low wind friction loss.

[0020] As a preferred mode, by arranging a variable frequency axial flow fan at the inlet of the cooling wind, the axial speed v of the cooling wind is adjusted in the range of 8m / s≤v≤25m / s, and when v exceeds 25m / s, the system automatically reduces the speed of the fan to suppress the increase of loss.

[0021] As a preferred mode, the no-load iron loss-voltage characteristic curve is drawn, and the test points are selected in the voltage interval of 0.8UN to 1.2UN with a step of 0.05UN, and the least squares fitting curve provides a basis for adaptive suppression of wind friction loss under different voltages.

[0022] As a preferred mode, the ratio of the no-load iron loss PFe and the wind friction loss Pfw is calculated in real time, and when the ratio is lower than 3, the system automatically adjusts the air gap δ or the axial speed v of the cooling wind until the ratio returns to the safe interval of 3-5.

[0023] A wind friction loss suppression system of a high-voltage magnetic suspension motor comprises:

[0024] An active magnetic suspension bearing is used to realize the contactless suspension of the rotor and provide an adjustable air gap δ.

[0025] A vacuum-normal pressure switchable cabin body.

[0026] A wind friction test module is used to measure the wind friction loss under normal pressure.

[0027] A mechanical friction test module is used to measure the mechanical friction loss under vacuum.

[0028] A data acquisition module is used to synchronously acquire three-phase voltage, current, active power, torque and speed.

[0029] A control module is used to calculate the no-load iron loss based on the law of conservation of energy, and output the adjustment instructions of the air gap δ and the cooling wind speed v according to the coupling relationship between the no-load iron loss and the wind friction loss, so as to realize the wind friction loss suppression.

[0030] The beneficial effects of the present application are: the present application effectively solves the core problems of lack of systematic optimization and poor dynamic adaptability in the prior art by constructing an integrated suppression method of measurement, coupling analysis and multi-parameter collaborative control. By comparing and measuring under normal pressure and high vacuum environment, the wind friction loss and the mechanical friction loss are accurately separated, the accuracy of loss evaluation is significantly improved, and the control deviation caused by the coupling of traditional methods is overcome; on this basis, based on the coupling relationship between the no-load iron loss and the wind friction loss, the suspension air gap length, the rotor surface roughness and the cooling wind speed are collaboratively optimized, the limitation of single structure optimization is broken through, and the systematic suppression of wind friction loss is realized. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0032] Figure 1 It is a flowchart of a wind friction loss suppression method of a high-voltage magnetic suspension motor.

[0033] Figure 2 It is a schematic diagram of the process of obtaining a constant loss Pcon of the motor. Detailed Implementation

[0034] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0035] 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 a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present 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.

[0036] like Figure 1 As shown, a method for suppressing wind friction loss in a high-voltage magnetic levitation motor includes the following steps:

[0037] Under no-load and stable stator winding temperature conditions, the high-voltage magnetic levitation motor synchronously collects the three-phase input voltage, current, active power and reactive power of the motor through a precision power analyzer (high-precision measuring equipment can provide very accurate electrical parameter data), and corrects the copper loss in real time based on the number of motor phases, line resistance and temperature coefficient, and calculates the constant loss Pcon of the motor.

[0038] The steps for calculating the constant loss Pcon of the motor (see...) Figure 2 ):

[0039] A1: Acquiring electrical parameters

[0040] Synchronously acquire the three-phase input voltage V of the motor line (Verify if the motor is operating at rated voltage), Three-phase input current I line Active power P in and reactive power Q in (Reactive power is very important for evaluating the power factor of a motor and the quality of the power grid, and it is also very important for comprehensively assessing the operating status of a motor and optimizing its operating conditions.)

[0041] A2: Calculate copper losses. Number of motor phases: Assume the motor is three-phase (m=3); Line resistance: Measured or known line resistance R. line Temperature coefficient: The temperature coefficient α of copper Cu ≈0.00393℃ -1Winding temperature: measure the actual temperature of the winding θ; Reference temperature: select a reference temperature θ0(such as 20℃ or 75℃); Correction resistance: correct the wire resistance to the reference temperature:

[0042]

[0043] Phase current effective value: calculate the effective value of each phase current I ph :

[0044]

[0045] Calculate copper loss P cu :

[0046]

[0047] A3: Calculate constant loss:

[0048] Input active power: the active power P measured by the power analyzer in ;

[0049] Constant loss: deduct the copper loss from the input active power to get the constant loss P con :

[0050] P con =P in -P cu

[0051] No-load condition ensures that the motor has no external mechanical load, so that the influence of mechanical load on motor loss can be excluded, so that the measured loss is mainly from the electrical loss inside the motor. The stable temperature rise of the stator winding indicates that the motor has entered steady-state operation, and the temperature no longer changes, which means that the thermal balance of the motor has been established, and the measured loss value is more stable and reliable.

[0052] The rotor is non-contactly sleeved on the power output shaft of the test driving device by using the active magnetic suspension bearing, and the wind friction torque Tfw and the corresponding speed n are measured by using the high-frequency response torque sensor and the laser tachometer in the normal pressure air environment, and the wind friction loss Pfw is converted to get;

[0053] The test driving device drives the rotor of the motor to rotate by providing power, so that it reaches the required test speed. The high-frequency response torque sensor is usually called dynamic torque sensor or high-precision torque sensor, which is used to measure the torque on the rotating shaft in real time. The laser tachometer is also called laser speed sensor or laser speed meter, which is a non-contact measuring device used to measure the speed of rotating objects.

[0054] Switch the chamber to an environment with a vacuum better than 10-2Pa, keep the same rotation speed n, measure the mechanical friction torque Tme and convert it to mechanical friction loss Pme;

[0055] According to the law of conservation of energy, the no-load iron loss PFe of the high-voltage magnetic suspension motor is calculated by the formula PFe = Pcon-Pfw-Pme;

[0056] Based on the coupling correlation curve of PFe and Pfw (by simulating or experimentally scanning the parameter combinations of δ, Ra, n, v, etc., and recording the corresponding PFe and Pfw values, the coupling curve can be drawn), adjust the suspension air gap length δ of the magnetic suspension bearing and the axial speed v of the cooling wind to suppress the wind friction loss. For example, the wind friction loss can be reduced by at least 20% at the rated speed.

[0057] Select the key parameters that affect PFe and Pfw, including:

[0058] Air gap length (δ): The air gap length has a significant impact on both wind friction loss and iron loss.

[0059] Rotor surface roughness (Ra): Roughness affects wind friction loss.

[0060] Rotation speed (n): Rotation speed affects both wind friction loss and iron loss.

[0061] Cooling wind speed (v): Cooling wind speed directly affects wind friction loss.

[0062] Data collection: Through simulation or experiment, scan the combinations of the above parameters, and record the corresponding PFe and Pfw values. The specific steps are as follows:

[0063] S1: Set parameter ranges:

[0064] Air gap length δ: from 3mm to 8mm;

[0065] Rotor surface roughness Ra: from 0.4μm to 1.6μm;

[0066] Rotation speed n: from 9,000r / min to 27,000r / min;

[0067] Cooling wind speed v: from 8m / s to 25m / s.

[0068] S2: Simulation or experiment:

[0069] Use finite element analysis software (such as ANSYS Maxwell) or experimental equipment to set different parameter combinations.

[0070] For each parameter combination, record the corresponding PFe and Pfw values.

[0071] The collected data is arranged in table form, such as:

[0072] Table 1 Data Record Table

[0073] Parameter combination δ (mm) Ra (pm) n (r / min) v (m / s) PFe (W) Pfw (W) 1 3 0.4 9,000 8 1000 200 2 3 0.4 12,000 8 1200 300 3 3 0.4 15,000 8 1500 400 … … … … … … … N 8 1.6 27,000 25 2000 800

[0074] S3: Use data fitting tools (such as MATLAB, Origin, etc.) to process the collected data, and draw the coupling correlation curve of PFe and Pfw.

[0075] By simulating or experimentally scanning parameter combinations, record the corresponding PFe and Pfw values, and draw the coupling correlation curve of PFe and Pfw. This process involves parameter selection, data collection, data recording and curve fitting, etc. The final curve can be used for optimizing motor design and real-time monitoring, improving motor efficiency and reliability.

[0076] In a preferred embodiment, in a normal pressure environment, the net torque Tfw required by the motor is recorded, and the real-time speed n of the rotor is measured by using an optical encoder, and the wind friction loss is calculated by the formula Pfw=2π·Tfw·n / 60.

[0077] In a normal pressure environment, we first use a high-precision torque sensor to record the net torque Tfw output by the motor. This net torque is the actual torque output by the motor to overcome air resistance. At the same time, we use an optical encoder to measure the real-time speed n of the rotor. The optical encoder is a non-contact measurement device that accurately calculates the number of revolutions per minute of the rotor by detecting the markings on the rotor. With these two key parameters, we can calculate the wind friction loss. Wind friction loss refers to the power consumed by the rotor in the air due to air resistance. This power is proportional to the torque and speed, that is, the greater the torque or the higher the speed, the greater the wind friction loss. By substituting the torque and speed into the formula, we can get the specific value of the wind friction loss. This process is not only accurate, but also can reflect the wind friction loss of the motor in different working conditions in real time, providing important data support for subsequent optimization and control.

[0078] In a preferred embodiment, at the same speed n, the rotor is placed in a vacuum chamber to eliminate air resistance, and a high-precision torque meter is used to measure the residual mechanical friction torque Tme, and the mechanical friction loss is obtained by the formula Pme=2π·Tme·n / 60, ensuring that the separation accuracy is better than ±2%.

[0079] To accurately measure the mechanical friction loss, we adopted a clever method to exclude the interference of wind friction loss. First, in a normal pressure environment, the motor rotor will produce a certain wind friction loss due to air resistance, which will mask the true mechanical friction loss. In order to accurately separate the mechanical friction loss, we put the rotor into a vacuum chamber and control the vacuum degree to better than 10-2P a . This can almost completely eliminate the influence of air resistance. In a vacuum environment, the rotation of the rotor is almost not hindered by air resistance, and the torque measured at this time is mainly derived from mechanical friction. We use a high-precision torque meter to measure this residual mechanical friction torque Tme. Without the interference of wind friction loss, this measurement can more accurately reflect the true situation of mechanical friction. By combining this torque value with the rotor speed n, we can calculate the mechanical friction loss Pme. This method can ensure the separation accuracy of the measurement to better than ±2%, thus providing reliable data support for the accurate evaluation of motor loss.

[0080] In a preferred embodiment, under the same supply voltage, frequency and winding temperature conditions, the motor constant loss Pcon measured by the power analyzer is deducted from the measured wind friction loss Pfw and mechanical friction loss Pme, and the formula PFe=Pcon-Pfw-Pme is used to obtain the no-load iron loss of the high-voltage magnetic suspension motor as the reference value for the subsequent suppression strategy.

[0081] In order to accurately obtain the no-load iron loss of the high-voltage magnetic suspension motor, we adopted a systematic measurement and calculation method. First, under the premise of ensuring that the key operating parameters such as the supply voltage, frequency and winding temperature of the motor remain consistent, the total input power of the motor is measured using a precision power analyzer, thereby obtaining the constant loss Pcon of the motor. This constant loss encompasses all types of losses of the motor in the no-load state, including iron loss, copper loss and mechanical loss, etc. However, our goal is to extract the no-load iron loss PFe alone in order to provide an accurate reference value for the subsequent loss suppression strategy. In order to achieve this goal, we need to eliminate the wind friction loss Pfw and mechanical friction loss Pme, which have been accurately measured through experiments, from Pcon. In this way, we can accurately calculate the no-load iron loss PFe, providing key data support for subsequent optimization and control strategies. This method not only improves the accuracy of the measurement, but also ensures the reliability and repeatability of the data, laying a solid foundation for further improvement of motor performance.

[0082] In a preferred embodiment, within the range of 3mm≤δ≤8mm, the suspension position of the magnetic suspension bearing is changed in real time using a precision displacement stage driven by a stepper motor, the trend of the wind friction loss decreasing exponentially with the increase of δ is monitored, and the optimal δ value is selected to achieve the maximum loss reduction.

[0083] To effectively reduce the wind friction loss of high-voltage magnetic suspension motor, we adjust the suspension air gap length δ of the magnetic suspension bearing. Specifically, within the range of 3mm to 8mm, we use a precision displacement table driven by a stepper motor to adjust the suspension position of the magnetic suspension bearing in real time. During the adjustment process, we continuously monitor the changes in wind friction loss. Through experimental observation, we found that as the air gap length δ gradually increases, the wind friction loss shows an exponential decline. This means that as the air gap length increases, the friction between the rotor and the cooling wind decreases significantly, thereby reducing the wind friction loss. Based on this phenomenon, we find the optimal air gap length δ value that can maximize the reduction of wind friction loss through multiple experiments and data analysis. By setting the air gap, we effectively suppress the wind friction loss.

[0084] In a preferred embodiment, the rotor outer surface roughness Ra is adjusted, a carbon fiber sleeve treated by multiple mirror polishing processes is applied to the rotor outer surface, the surface roughness Ra is controlled within 0.4μm≤Ra≤1.6μm, and an online roughness detector is used to monitor the Ra changes, and the polishing is performed as necessary to maintain low wind friction loss.

[0085] To effectively reduce the wind friction loss of high-voltage magnetic suspension motor, we adopt a special surface treatment method. First, a layer of carbon fiber sleeve is installed on the outer surface of the rotor, which is treated by multiple mirror polishing processes to ensure its high surface smoothness. Through fine polishing process, we strictly control the surface roughness Ra of the sleeve within 0.4μm to 1.6μm, which can ensure the surface of the rotor to be smooth enough to reduce wind friction loss, and also will not increase the manufacturing cost or affect other performance due to excessive polishing. In order to ensure that the surface roughness always remains within the ideal range, an online roughness detector can be used for real-time monitoring. Once the Ra exceeds the set range, the carbon fiber sleeve is further polished to maintain low wind friction loss. Through this dynamic monitoring and adjustment mechanism, we can ensure that the motor always maintains the best surface state during operation, thereby effectively reducing the wind friction loss and improving the operating efficiency and reliability of the motor.

[0086] In a preferred embodiment, by arranging a variable frequency axial flow fan at the cooling wind inlet, the PLC closed-loop control system adjusts the cooling wind axial speed v within 8m / s≤v≤25m / s, and when v exceeds 25m / s, the system automatically reduces the fan speed to suppress the increase in loss.

[0087] To effectively control the cooling air speed of high-voltage magnetic levitation motors and optimize wind friction loss, a variable frequency axial fan and a PLC closed-loop control system are used. First, a variable frequency axial fan is installed at the cooling air inlet. This fan can adjust the air speed by changing the frequency, allowing flexible control of the axial speed v of the cooling air. To ensure that the air speed is always within the optimal range, an adjustment interval of 8 m / s to 25 m / s is set. This ensures sufficient cooling effect without increasing unnecessary energy consumption and wind friction loss due to excessive air speed.

[0088] Next, the fan is precisely controlled through a PLC closed-loop control system. The PLC system monitors the cooling air speed in real time. Once it detects that the air speed v exceeds 25 m / s, the system automatically reduces the fan speed to bring the air speed back within the set reasonable range. This automatic adjustment mechanism effectively suppresses the increase in loss caused by excessive air speed, while ensuring that the motor operates under efficient and stable cooling conditions. Through this intelligent control method, not only can the cooling efficiency of the motor be optimized, but also the additional loss caused by improper cooling air speed can be reduced, thereby improving the overall operating efficiency and reliability of the motor.

[0089] In a preferred embodiment, a no-load iron loss-voltage characteristic curve is drawn, and test points are selected at 0.05UN intervals within the 0.8UN to 1.2UN voltage range. The least squares method is used to fit the curve to provide a basis for adaptive suppression of wind friction loss at different voltages.

[0090] To better optimize the wind friction loss of high-voltage magnetic levitation motors at different voltages, a systematic testing and analysis method is used to draw the characteristic curve between no-load iron loss and voltage. Specifically, within the range of 80% to 120% of the motor's rated voltage UN, i.e., from 0.8UN to 1.2UN, a series of test points are selected at 0.05UN intervals. This is to obtain enough data points to accurately depict the trend of no-load iron loss with voltage.

[0091] At each selected voltage test point, the no-load iron loss of the motor is measured. These measurement data are like a series of coordinate points distributed on the two-dimensional plane formed by voltage and no-load iron loss. To extract a continuous curve that can describe the overall trend from these discrete data points, the least squares method is used for curve fitting. The least squares method is a mathematical method that calculates the sum of the squares of the perpendicular distances from all data points to the fitted curve, and minimizes this sum to find the curve that best represents the trend of these data points.

[0092] The fitted no-load iron loss-voltage characteristic curve provides a very valuable reference for us. This curve clearly shows the variation of the motor's no-load iron loss at different voltage levels. Based on this curve, we can provide scientific basis for the adaptive suppression strategy of wind friction loss at different voltages. In short, this curve is like a compass, helping us to accurately adjust and optimize the suppression measures of wind friction loss during the operation of the motor according to the actual voltage situation, so as to ensure that the motor can maintain high efficiency and stable operation under various working conditions.

[0093] In a preferred embodiment, in order to further optimize the wind friction loss suppression effect of the high-voltage magnetic suspension motor, an adaptive adjustment mechanism based on the dynamic response characteristics of the rotor is introduced. During the operation of the motor, the vibration frequency f and the vibration amplitude A of the rotor are monitored in real time. The vibration frequency f represents the number of vibrations of the rotor per unit time, with the unit being hertz (Hz); the vibration amplitude A represents the maximum deviation of the rotor vibration, with the unit being millimeters (mm). By analyzing the vibration characteristics of the rotor, it can be judged whether the motor is in a stable state and whether there is a potential wind friction loss anomaly. Based on the dynamic response characteristics of the rotor, the adaptive adjustment formula is used to optimize the wind friction loss suppression strategy:

[0094]

[0095] Where Δv represents the adjustment amount of the cooling air axial velocity, with units of meters per second (m / s); k is the adjustment coefficient, whose value is pre-set according to the specific parameters and operating conditions of the motor, and the value range can be 40-60. 1000 is a unit conversion constant, used to convert mm to m. When the rotor vibration amplitude A increases or the vibration frequency f decreases, it indicates that the motor may have an abnormally increased risk of wind friction loss. At this time, the adjustment amount Δv of the cooling air axial velocity is calculated according to the above formula, and the cooling air speed is increased accordingly to enhance the cooling effect and reduce the rotor temperature, thereby reducing the wind friction loss. At the same time, combined with the adjustment of the air gap length δ, the operating state of the motor is further optimized. The adjustment principle of the suspension air gap length δ: The winding current of the active magnetic suspension bearing can change the position of the rotor geometric center in real time, allowing δ to be adjusted steplessly between 3-8 mm; the displacement sensor feeds back the current δ value to the control module at high speed, forming a displacement and current closed loop to ensure that the adjustment is both fast and free of mechanical contact wear. The operating optimization principle: The control module has a loss-δ monotonically decreasing curve, and when it is detected that the wind friction loss is still on the falling edge, δ is slightly increased; once the curve enters the flat area, the current δ is locked, allowing the motor to balance between low wind friction loss and controllable bearing power consumption. Through this adaptive adjustment mechanism based on the dynamic response characteristics of the rotor, the system can more accurately respond to various complex operating conditions during motor operation, dynamically adjust the cooling air speed and air gap length, achieve efficient suppression of wind friction loss, and further improve the operating efficiency and stability of the high-voltage magnetic suspension motor.

[0096] In a preferred embodiment, the ratio η = PFe / Pfw of the no-load iron loss PFe and the wind friction loss Pfw is calculated in real time. When η is lower than 3, the system automatically adjusts the air gap δ or the cooling air axial velocity v until η returns to the safe interval of 3-5.

[0097] The system takes η = PFe / Pfw as the "steering wheel". When η < 3, it means that the iron loss is too small and the wind friction is too much, so δ is first enlarged, and if the temperature is still safe, v is slightly reduced to further reduce the wind resistance. When η > 5, it means that the iron loss is too much, so δ is first reduced slightly and v is increased to remove the extra heat until η returns to the interval of 3-5. The ratio η of the no-load iron loss PFe and the wind friction loss Pfw is monitored and calculated in real time. By continuously tracking this ratio, we can accurately grasp the loss situation of the motor under different operating conditions. When the value of η is lower than 3, it indicates that the wind friction loss is relatively high, which may adversely affect the efficiency of the motor. At this time, the system will automatically start the adjustment mechanism to optimize the operating state of the motor by adjusting the air gap length δ of the magnetic suspension bearing or changing the axial velocity v of the cooling air. This automatic adjustment process will continue until the value of η returns to the safe interval of 3 to 5. This safe interval can ensure the efficient operation of the motor and avoid performance degradation due to excessive loss.

[0098] In a preferred embodiment, all tests and operating conditions should be powered by a consistent power supply, including input line voltage fluctuations not exceeding ±1%, frequency fluctuations not exceeding ±0.1 Hz, and three-phase imbalance not exceeding 1%. A combination of regulated frequency power supply and UPS uninterruptible power supply ensures data repeatability and effectiveness of the suppression strategy.

[0099] To ensure the accuracy and stability of high-voltage magnetic suspension motor tests and operating conditions, all tests and operating conditions must be powered by a consistent power supply. Specifically, the input line voltage fluctuation should be controlled within ±1%, the frequency fluctuation should not exceed ±0.1 Hz, and the three-phase imbalance should not exceed 1%. These strict standards are to ensure that the motor can obtain consistent power input under different test and operating conditions, thus ensuring data repeatability and reliability.

[0100] To meet these requirements, we use a combination of regulated frequency power supply and UPS uninterruptible power supply. Regulated frequency power supply can effectively stabilize voltage and frequency, ensuring the stability and consistency of power output. UPS uninterruptible power supply can quickly provide stable power support in the event of instantaneous power failure or voltage fluctuation, ensuring the continuity and stability of motor operation. Through this double protection, we not only ensure that the motor obtains high-quality power supply during testing and operation, but also provide a solid foundation for subsequent loss suppression strategies, thus ensuring the effectiveness and repeatability of these strategies. This rigorous power management measure is the key to ensuring the smooth progress of motor performance testing and optimization work.

[0101] A high-voltage magnetic suspension motor wind friction loss suppression system, comprising:

[0102] A high-voltage magnetic suspension motor body, in this embodiment, its rated line voltage ≥ 6kV;

[0103] Active magnetic suspension bearing, used to realize the non-contact suspension of the rotor and provide adjustable air gap δ;

[0104] Vacuum-ambient switchable cabin, equipped with test drive shaft, vacuum pump and sealing valve inside; test drive shaft is a key component for supporting and driving the motor rotor to rotate. It connects the motor rotor and test equipment to ensure the rotor can rotate stably during testing and can withstand the required speed and torque. The vacuum pump is used to create a vacuum environment in the test cabin. The sealing valve is used to control the air pressure and vacuum degree in the test cabin.

[0105] Wind friction test module, containing high-frequency response torque sensor and laser tachometer, used to measure wind friction loss under normal pressure; high-frequency response torque sensor is used to measure the torque output by the motor in real time. It can quickly respond to changes in torque, suitable for dynamic testing environment. Laser tachometer is used to measure the real-time speed of the motor rotor. It is a non-contact measuring device that does not cause wear to the rotor.

[0106] Mechanical friction test module, containing high-precision torque meter, used to measure mechanical friction loss under vacuum; high-precision torque meter is used to measure mechanical friction torque in vacuum environment. It can provide high-precision torque measurement data to ensure the reliability of the measurement results. High-precision torque meter is usually based on strain gauge or torque sensor principle. It calculates the size of the torque by measuring the strain or torque change on the shaft.

[0107] Data acquisition module, synchronously acquires three-phase voltage, current, active power, torque and speed;

[0108] Control module, based on the law of conservation of energy to calculate no-load iron loss, and according to the coupling relationship between no-load iron loss and wind friction loss, output adjustment instructions of air gap δ and cooling wind speed v, realize wind friction loss closed loop suppression.

[0109] The system aims to effectively suppress the wind friction loss of high-voltage magnetic levitation motor, its core components and working principle are as follows:

[0110] First of all, the system contains a high-voltage magnetic levitation motor, whose rated line voltage is not less than 6kV, which is the basic equipment for system operation. The motor is equipped with active magnetic bearing, which can realize the non-contact suspension of the rotor and can adjust the size of the air gap δ. This adjustable air gap is the key because it directly affects the size of the wind friction loss, by accurately controlling the air gap, the running efficiency of the motor can be optimized.

[0111] The system also contains a vacuum-normal pressure switchable cabin, which is equipped with test drive shaft, vacuum pump and sealing valve inside. The role of this cabin is to create a vacuum environment when needed to exclude air resistance, so as to accurately measure the mechanical friction loss. Under normal pressure environment, the wind friction test module starts to work, which contains high-frequency response torque sensor and laser tachometer, used to accurately measure wind friction loss. While in vacuum environment, mechanical friction test module uses high-precision torque meter to measure mechanical friction loss. The combination of these two modules ensures the accuracy of loss measurement.

[0112] The data acquisition module synchronously acquires three-phase voltage, current, active power, torque and speed, etc. These data are the basis for the system to carry out accurate control, which provides necessary information for subsequent calculation and adjustment.

[0113] Finally, the control module is the "brain" of the system. It calculates the no-load iron loss based on the law of conservation of energy, and outputs the instructions to adjust the air gap δ and the cooling wind speed v according to the coupling relationship between the no-load iron loss and the wind friction loss. This closed-loop control system can monitor and adjust in real time to ensure that the wind friction loss is always in the optimal state. In this way, the system not only improves the operating efficiency of the motor, but also enhances its stability and reliability.

[0114] In a preferred embodiment, the wind friction test module obtains the wind friction torque Tfw in real time through the torque sensor, combines the rotational speed n, and calculates the wind friction loss according to the formula Pfw = 2π·Tfw·n / 60; the mechanical friction test module measures the mechanical friction torque Tme in a vacuum environment through the torque meter, combines the rotational speed n, and obtains the mechanical friction loss according to the formula Pme = 2π·Tme·n / 60.

[0115] During the test process of the high-voltage magnetic levitation motor, the wind friction test module and the mechanical friction test module are used to measure the wind friction loss and the mechanical friction loss, respectively. The working principles and functions of these two modules are closely related, and they jointly provide key data for the performance evaluation of the motor.

[0116] First, the wind friction test module monitors the wind friction torque Tfw of the motor in the normal pressure environment in real time through the high-precision torque sensor. This torque is the additional torque generated by the air resistance when the motor rotor rotates in the air. At the same time, the laser tachometer accurately measures the real-time rotational speed n of the rotor. Through these two parameters, we can calculate the wind friction loss Pfw. Wind friction loss refers to the power consumed by the motor to overcome air resistance, which is one of the important indicators of motor operating efficiency.

[0117] Next, the mechanical friction test module works in a vacuum environment. In a vacuum environment, air resistance is completely excluded, and the rotor rotates only under the influence of mechanical friction. Through the high-precision torque meter, we measure the mechanical friction torque Tme generated by the friction between the motor rotor and the bearing. Similarly, the laser tachometer measures the real-time rotational speed n of the rotor. Through these two parameters, we can calculate the mechanical friction loss Pme. Mechanical friction loss refers to the loss generated by the friction between the internal mechanical components of the motor, which is also an important factor affecting the efficiency of the motor.

[0118] The measurement results of these two modules not only help us accurately separate the wind friction loss and the mechanical friction loss, but also provide a scientific basis for subsequent optimization and control strategies. By comparing the changes in wind friction loss and mechanical friction loss under different conditions, we can find the best operating parameters to improve the operating efficiency and reliability of the motor. This step-by-step measurement and analysis method ensures that we can comprehensively and accurately evaluate the performance of the motor, providing strong support for the efficient operation of the high-voltage magnetic levitation motor.

[0119] In a preferred embodiment, the control module has built-in no-load iron loss calculation logic that updates the no-load iron loss in real time according to the formula PFe = Pcon - Pfw - Pme, and takes the ratio η of the no-load iron loss to the wind friction loss as the closed-loop control input. The active magnetic suspension bearing automatically adjusts the air gap length δ between 3mm and 8mm under the instruction of the control module and feeds back in real time through the displacement sensor, ensuring that the wind friction loss is continuously suppressed.

[0120] In the wind friction loss suppression system of the high-voltage magnetic suspension motor, the control module plays a core role, which ensures that the motor always maintains high efficiency during operation. The control module has a built-in no-load iron loss calculation method, which can accurately calculate the no-load iron loss PFe of the motor according to real-time data. Specifically, it updates the value of no-load iron loss by deducting wind friction loss Pfw and mechanical friction loss Pme from the constant loss Pcon of the motor. This process is like a dynamic balancing process, ensuring that we can always accurately grasp the iron loss of the motor under different working conditions.

[0121] In order to further optimize the operation efficiency of the motor, the control module also takes the ratio η of the no-load iron loss to the wind friction loss as the input signal of the closed-loop control. This ratio η is a key performance indicator that reflects the relationship between the iron loss and the wind friction loss of the motor during operation. By monitoring this ratio in real time, the control module can intelligently adjust the operating parameters of the motor to achieve the best performance state.

[0122] In actual operation, the active magnetic suspension bearing automatically adjusts the air gap length δ according to the instruction of the control module. The adjustment range of the air gap length is set between 3mm and 8mm, which is carefully designed to ensure stable operation of the motor and effectively reduce the wind friction loss. At the same time, the system is equipped with a high-precision displacement sensor to feedback the changes of the air gap length in real time. This real-time feedback mechanism ensures the adjustment accuracy of the air gap length, so that the wind friction loss can be continuously suppressed.

[0123] Through this intelligent closed-loop control strategy, the system can dynamically adjust the air gap length according to the actual operation of the motor, so as to effectively suppress the wind friction loss. This method not only improves the operation efficiency of the motor, but also enhances the stability and reliability of the system, providing a strong guarantee for the efficient operation of the high-voltage magnetic suspension motor.

[0124] In summary, the application constructs a complete wind friction loss inhibition system through four steps of normal pressure-vacuum double working condition test, energy conservation separation loss, coupling curve solidification and ratio closed loop regulation. The system monitors the ratio of no-load iron loss and wind friction loss η in real time: when η is lower than 3, it is determined that the wind friction ratio is too high, the air gap δ is first slightly increased to weaken the shear effect of the rotor and air, and / or the cooling wind speed v is appropriately reduced to reduce the wind friction loss; when η is higher than 5, the δ is reversely slightly reduced and / or the v is increased to inhibit the iron loss and prevent overheating. The linkage adjustment of air gap and wind speed is executed by the closed loop of active magnetic suspension bearing and variable frequency fan, forming millisecond level response, ensuring that the motor always runs at the loss-cooling balance point in the full speed and full load range, and realizing the ultimate goal of high efficiency, reliable and long service life operation of high voltage magnetic suspension motor.

[0125] Although the preferred embodiments of the application have been described, those skilled in the art who understand the basic inventive concept can make additional changes and modifications to the embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the application. The above description is only the preferred embodiment of the application and is not intended to limit the application. It should be noted that any modification, equivalent replacement and improvement made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A method for suppressing windage loss of a high-voltage magnetic levitation motor, characterized by, The method comprises the following steps: Collecting three-phase input voltage, current, active power and reactive power, and correcting copper loss in real time according to motor phase number, line resistance and temperature coefficient to obtain motor constant loss Pcon; The rotor is non-contactly sleeved on the power output shaft of the test driving device by using the active magnetic suspension bearing, the wind friction torque Tfw and the corresponding rotating speed n are measured in the normal pressure air environment, and the wind friction loss Pfw is converted and obtained; Switching the chamber to an environment with a vacuum better than 10"2P a Keeping the same rotation speed n, the mechanical friction torque Tmeis measured and converted into mechanical friction loss Pme; The no-load iron loss PFe of the high-voltage magnetic suspension motor is calculated through the formula PFe=Pcon-Pfw-Pme; Based on the coupling correlation curve of PFe and Pfw, the suspension air gap length δ of the magnetic suspension bearing and the axial speed v of the cooling wind are adjusted to suppress the wind friction loss.

2. The method of claim 1, wherein the method further comprises: In the normal pressure environment, the net torque Tfw required by the motor is recorded, and the real-time rotating speed n of the rotor is measured by using the photoelectric encoder, and the wind friction loss is calculated through the formula Pfw=2π·Tfw·n / 60.

3. The method of claim 1 or 2, wherein the method further comprises: In the same rotating speed n, the rotor is placed in the vacuum chamber to eliminate air resistance, the residual mechanical friction torque Tme is measured, and the mechanical friction loss is obtained through the formula Pme=2π·Tme·n / 60.

4. The method of claim 1-3, wherein, Under the same power supply voltage, frequency and winding temperature conditions, the motor constant loss Pcon is deducted from the measured wind friction loss Pfw and mechanical friction loss Pme, and the no-load iron loss of the high-voltage magnetic suspension motor is obtained by using the formula PFe=Pcon-Pfw-Pme as the reference value for the subsequent suppression strategy.

5. The method of claim 1, wherein the method further comprises: In the range of 3mm≤δ≤8mm, the suspension position of the magnetic suspension bearing is changed, the trend of the wind friction loss decreasing exponentially with the increase of δ is monitored, and the optimal δ value is selected to realize the maximum loss reduction.

6. The method of claim 1 or 5, wherein, The rotor outer surface roughness Ra is adjusted, the carbon fiber sleeve treated by multi-pass mirror polishing process is applied to the rotor outer surface, the surface roughness Ra is controlled in the range of 0.4μm≤Ra≤1.6μm, and the online roughness detector is used to monitor the Ra change, and the polishing is performed again if necessary to maintain the low wind friction loss.

7. The method of claim 1, wherein the method further comprises: The cooling wind axial speed v is adjusted in the range of 8m / s≤v≤25m / s by arranging the variable frequency axial flow fan at the cooling wind inlet, and the fan rotating speed is automatically reduced when v exceeds 25m / s to suppress the loss increase.

8. The method of claim 1, wherein the method further comprises: The no-load iron loss-voltage characteristic curve is drawn, the test points are selected in the voltage interval of 0.8UN to 1.2UN with a step of 0.05UN, and the least square method is used to fit the curve to provide a basis for adaptive suppression of wind friction loss under different voltages.

9. The method of claim 1, wherein the method further comprises: The ratio η=PFe / Pfw of the no-load iron loss PFe and the wind friction loss Pfw is calculated in real time, and when η is lower than 3, the system automatically adjusts the air gap δ or the cooling wind axial speed v until η returns to the safe interval of 3-5.

10. A high voltage maglev motor windage loss suppression system, characterized in that, It comprises: An active magnetic suspension bearing for realizing non-contact suspension of the rotor and providing an adjustable air gap δ; A vacuum-normal pressure switchable cabin; A wind friction test module for measuring the wind friction loss in normal pressure; A mechanical friction test module for measuring the mechanical friction loss in vacuum; A data acquisition module for synchronously collecting three-phase voltage, current, active power, torque and rotating speed; The control module calculates the no-load iron loss based on the law of conservation of energy, and outputs the adjustment instruction of the air gap δ and the cooling wind speed v according to the coupling relationship between the no-load iron loss and the wind friction loss, so as to realize the wind friction loss suppression.

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