Winding end portion media enhancement process to improve motor operating life

Abstract

This invention relates to various applications of materials not included in other categories and to the field of functional composite media technology. It discloses a method for enhancing the dielectric reinforcement of winding ends to improve the service life of a motor. The method includes: incorporating nanoparticles and a latent polar diluent into a resin to obtain a reinforcing medium; placing a substrate in a sealed chamber to eliminate air gaps; injecting the medium and applying gradient pressure and a pulsating sound field; heating the impregnated substrate to the boiling point of the diluent; utilizing the surface tension gradient to drive the nanoparticles to migrate and accumulate at the phase interface; and heating to solidify and construct a charge-blocking network. This invention utilizes the Marangoni micro-convection mechanism to overcome the curing steric hindrance, enabling the functional components to be directionally reconstructed in a strong electric field region, suppressing corona discharge and blocking the evolution of electrical trees, thereby improving the reliability of the insulation system under alternating stress over a wide temperature range.

Description

Technical Field

[0001] This invention belongs to the field of various applications of materials not included in other categories and the field of functional composite media technology, and particularly relates to a method for improving the dielectric reinforcement treatment of winding ends to enhance the service life of motors. Background Technology

[0002] Currently, high-voltage motor winding ends typically employ a composite reinforcing medium composed of a thermosetting resin matrix and inorganic fillers. This medium is filled into the winding gaps through a vacuum pressure impregnation process. The dielectric strength of the medium and the polarization characteristics of the filler are used to increase the corona initiation voltage, thereby suppressing partial discharge. With the increasing demand for high-altitude rail transit and aerospace electrical systems, motors operate in low-pressure environments at 5000 meters and in a wide temperature range of -40℃ to 55℃. During operation, the winding ends are subjected to high electric field distortion and intense alternating thermal stress. Existing technologies focus on the static control of macroscopic pressure during the impregnation molding stage, neglecting the thermodynamic response of the internal components of the composite medium within the curing window.

[0003] To address the aforementioned shortcomings, the industry has attempted to extend the impregnation time or increase the injection molding pressure. However, such methods struggle to overcome the physical constraints imposed by the viscosity surge on component spatial reconstruction. For instance, Chinese invention patent CN102690496B discloses a nano-modified epoxy vacuum pressure impregnation resin and its preparation method. It employs high-shear dispersion and grinding processes to achieve macroscopic uniform dispersion of nanoparticles in the resin matrix, thereby improving thermal conductivity and corona resistance. However, in actual operation, winding end insulation failure begins at the interface between the conductor and the insulating medium. The uniformly dispersed system constructed by mechanical external force is limited in its curing process after entering the micropores of the winding by the viscosity surge caused by resin crosslinking. Functional components are frozen in situ within the bulk phase and cannot migrate to the interface region with strong electric field distortion. The globally uniform and locally random component distribution makes it difficult to construct a charge blocking network at the critical phase interface, and the impact of interface stress generated by curing shrinkage on the structural stability of the insulation layer is not considered.

[0004] Therefore, the technical problem to be solved by this invention is to regulate the micro-hydrodynamic behavior of composite media before gelation, develop an application material processing scheme with adaptive reconstruction characteristics to drive the directional aggregation of functional components and synergistically compensate for interfacial shrinkage stress, and improve the robustness of the insulation system under extreme conditions. Summary of the Invention

[0005] This invention aims to solve the problems of uncontrollable component distribution during the curing window of existing insulating media and the decline in insulation reliability caused by the accumulation of phase interface stress.

[0006] In this technical solution, a method for improving the service life of a motor by enhancing the dielectric at the winding ends includes the following steps:

[0007] In step S101, under a vacuum environment with a pressure below 50 Pa, surface fluorinated nanoparticles with a molar fraction of 3.0% to 8.0% and a latent polar diluent with a mass fraction of 1.5% to 3.0% are incorporated into the matrix resin, and the composite reinforcing medium is obtained by shear mixing; wherein, the atmospheric pressure boiling point temperature of the latent polar diluent is lower than the initial gel temperature of the matrix resin.

[0008] Step S102: Place the porous electromagnetic substrate to be treated in a sealed chamber, and alternately establish the first negative pressure limit value and the second micro negative pressure recovery value to expel the adsorbed gas inside the micropores of the porous electromagnetic substrate.

[0009] Step S103: Inject composite reinforcing medium into the sealed chamber, apply gradient pressure sequence and low-frequency pulsating sound field with a frequency of 20Hz to 50Hz to drive the composite reinforcing medium to penetrate into the deep micropores of the porous electromagnetic substrate.

[0010] Step S104: Excess liquid phase is drained, and the porous electromagnetic substrate that has been impregnated is subjected to a two-stage programmed temperature rise: the substrate is heated to the boiling point temperature range of the latent polar diluent at a first heating rate and maintained at a constant temperature. The latent polar diluent vaporizes at the phase interface of the porous electromagnetic substrate, generating a surface tension gradient from the phase interface to the center of the matrix resin, driving the surface fluorinated nanoparticles to migrate to the phase interface and accumulate. The substrate is then heated to the crosslinking temperature plateau of the matrix resin at a second heating rate. The crosslinking reaction of the matrix resin is used to anchor the surface fluorinated nanoparticles at the phase interface, constructing a space charge blocking network at the phase interface.

[0011] Preferably, in step S101, the surface fluorinated nanoparticles include silicon carbide nanoparticles or alumina nanoparticles that have undergone plasma fluorination treatment; the average particle size of the surface fluorinated nanoparticles is 20 nm to 50 nm, and the atomic ratio of fluorine to oxygen on the surface of the surface fluorinated nanoparticles is not less than 0.8.

[0012] Preferably, in step S103, the sound pressure level of the low-frequency pulsating sound field is 100dB to 120dB, which is used to break the transient flocculation structure of the surface fluorinated nanoparticles inside the matrix resin.

[0013] Preferably, in step S103, the gradient pressure sequence includes at least three pressure gradients increasing from 1.0 kPa to 600 kPa, and the duration of each pressure gradient is 30 min to 60 min.

[0014] Preferably, in step S104, the first heating rate is 1.0℃ / min to 2.0℃ / min; and the isothermal maintenance time in the boiling point temperature range is 20min to 40min.

[0015] Preferably, in step S101, the latent polar diluent includes propylene carbonate or dimethyl phthalate; and the surface tension value of the latent polar diluent at 25°C is lower than that of the matrix resin.

[0016] Preferably, the space charge retardation network produced in step S104 has a deep trap energy level density at the phase interface that is not lower than .

[0017] Preferably, after step S103 and before step S104, the method further includes: using dry nitrogen to remove liquid from the surface of the porous electromagnetic substrate, so that the composite reinforcing medium is retained inside the micropores of the porous electromagnetic substrate.

[0018] Preferably, after step S104 is completed, the method further includes: decreasing the temperature at a constant cooling rate to the glass transition temperature range of the composite reinforcing medium and maintaining a relaxation plateau to eliminate microscopic interfacial thermal stress at the phase interface.

[0019] Compared with existing technologies, the winding end dielectric reinforcement treatment method of the present invention for improving the service life of motors has the following advantages:

[0020] 1. In the dielectric reinforcement treatment at the winding end, by introducing a latent polar component with a boiling point matching the gel temperature of the matrix resin into the composite reinforcement medium, the surface tension gradient induced by the local phase change generated at the winding interface during the heating process is utilized to transform the originally quasi-static heat conduction process into an active material transport path at the microscale. This Marangoni micro-convection mechanism based on thermodynamics effectively overcomes the spatial steric hindrance constraint on the migration of functional components caused by the viscosity surge during the cross-linking and curing stage of thermosetting media. This allows fluorinated nanoparticles with surface polarity to directionally aggregate and anchor at the insulating phase interface where the electric field distribution is relatively concentrated before the matrix resin completely loses its fluidity, thus constructing a space charge retardation network with a high depth trap density at the microscale.

[0021] 2. By relying on the deep coupling between the polar induction effect of surface fluorinated nanoparticles and the microscopic convection mechanism generated by heating, the functional components inside the insulating medium are autonomously reconstructed from a uniform distribution to a directional gradient distribution, expanding the application boundaries of multiphase functional composite materials in extreme alternating stress environments. This self-assembly process of component distribution, based on the ability of the winding end insulation system to actively capture and dissipate injected charges, significantly improves the corona initiation voltage at the winding end in high-altitude and low-pressure environments at 5000 meters. From the perspective of the intrinsic properties of materials, it blocks the evolution path of electrical trees caused by partial discharge and reduces the risk of penetrating electrical aging of high-voltage equipment under extreme wide-temperature alternating stress.

[0022] 3. By employing a nonlinearly increasing gradient pressure sequence combined with a low-frequency pulsating sound field in a specific frequency band, the capillary resistance of the deep micropores in the winding is overcome, while the transient flocculation structure of nanoparticles is broken in situ using sound wave energy. This fluid dynamics control strategy ensures that the high-viscosity composite medium and its internal functional filler penetrate into the insulation layer simultaneously, eliminating the component mismatch caused by powder interception in the traditional impregnation process, ensuring the dense filling of the micro air gaps at the winding ends without blind spots, and enhancing the interfacial wettability between the composite medium and the winding conductor and insulating paper. Attached Figure Description

[0023] Figure 1 This is a logic diagram of the medium enhancement processing for interface-oriented reconstruction in this invention;

[0024] Figure 2 This is the execution architecture diagram of the media processing system under multi-field coupling of the present invention. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0026] It should be noted that all directional and positional terms used in this invention, such as: up, down, left, right, front, back, vertical, horizontal, inner, outer, top, bottom, transverse, longitudinal, center, etc., are only used to explain the relative positional relationship and connection between components in a specific state (as shown in the accompanying drawings). They are only for the convenience of describing this invention and do not require that this invention be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention. In addition, the descriptions of "first," "second," etc., in this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0027] In the description of this invention, unless otherwise explicitly specified and limited, the terms installation, connection, and linking should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0028] In the description of this specification, references to the terms "an embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example, and the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0029] A method for improving the service life of a motor by reinforcing the dielectric at the winding ends includes the following steps:

[0030] In step S101, under a vacuum environment with a pressure lower than 50 Pa, surface fluorinated nanoparticles with a molar fraction of 3.0% to 8.0% and a latent polar diluent with a mass fraction of 1.5% to 3.0% are incorporated into the matrix resin, and the composite reinforcing medium is obtained by shear mixing; wherein, the atmospheric pressure boiling point temperature of the latent polar diluent is lower than the initial gel temperature of the matrix resin.

[0031] Step S102: Place the porous electromagnetic substrate to be treated in a sealed chamber, and alternately establish the first negative pressure limit value and the second micro negative pressure recovery value to expel the adsorbed gas inside the micropores of the porous electromagnetic substrate.

[0032] Step S103: Inject composite reinforcing medium into the sealed chamber, apply gradient pressure sequence and low-frequency pulsating sound field with a frequency of 20Hz to 50Hz to drive the composite reinforcing medium to penetrate into the deep micropores of the porous electromagnetic substrate.

[0033] Step S104: Excess liquid phase is drained, and the porous electromagnetic substrate that has been impregnated is subjected to a two-stage programmed temperature rise: the substrate is heated to the boiling point temperature range of the latent polar diluent at a first heating rate and maintained at a constant temperature. The latent polar diluent vaporizes at the phase interface of the porous electromagnetic substrate, generating a surface tension gradient from the phase interface to the center of the matrix resin, driving the surface fluorinated nanoparticles to migrate to the phase interface and accumulate. The substrate is then heated to the crosslinking temperature plateau of the matrix resin at a second heating rate. The crosslinking reaction of the matrix resin is used to anchor the surface fluorinated nanoparticles at the phase interface, constructing a space charge blocking network at the phase interface.

[0034] Preferably, in step S101, the surface fluorinated nanoparticles include silicon carbide nanoparticles or alumina nanoparticles that have undergone plasma fluorination treatment; the average particle size of the surface fluorinated nanoparticles is 20 nm to 50 nm, and the atomic ratio of fluorine to oxygen on the surface of the surface fluorinated nanoparticles is not less than 0.8.

[0035] Preferably, in step S103, the sound pressure level of the low-frequency pulsating sound field is 100dB to 120dB, which is used to break the transient flocculation structure of the surface fluorinated nanoparticles inside the matrix resin.

[0036] Preferably, in step S103, the gradient pressure sequence includes at least three pressure gradients increasing from 1.0 kPa to 600 kPa, and the duration of each pressure gradient is 30 min to 60 min.

[0037] Preferably, in step S104, the first heating rate is 1.0℃ / min to 2.0℃ / min; and the isothermal maintenance time in the boiling point temperature range is 20min to 40min.

[0038] Preferably, in step S101, the latent polar diluent includes propylene carbonate or dimethyl phthalate; and the surface tension value of the latent polar diluent at 25°C is lower than that of the matrix resin.

[0039] Preferably, the space charge retardation network produced in step S104 has a deep trap energy level density at the phase interface that is not lower than .

[0040] Preferably, after step S103 and before step S104, the method further includes: using dry nitrogen to remove liquid from the surface of the porous electromagnetic substrate, so that the composite reinforcing medium is retained inside the micropores of the porous electromagnetic substrate.

[0041] Preferably, after step S104 is completed, the method further includes: decreasing the temperature at a constant cooling rate to the glass transition temperature range of the composite reinforcing medium and maintaining a relaxation plateau to eliminate microscopic interfacial thermal stress at the phase interface.

[0042] Example 1: In a specific application of the present invention, the winding end dielectric reinforcement treatment method for improving the service life of a motor is used in a special motor operating environment with an altitude of 5000m and an ambient temperature fluctuation range of -40℃ to 55℃. In this environment, the air density is low, easily inducing corona discharge. This method suppresses electric field distortion at the winding end by reshaping the intrinsic electrical properties of the insulating dielectric. The specific steps for obtaining the composite reinforced dielectric include: […]. A high-grade resin matrix is ​​placed in a vacuum container at a pressure below 50 Pa. Surface-fluorinated nanoparticles with a molar fraction of 3.0% to 8.0% and a latent polar diluent with a mass fraction of 1.5% to 3.0% are added. The mixture is stirred for 45 minutes using a high-speed shear stirrer at 2500 rpm to form a uniform dispersion of the surface-fluorinated nanoparticles in the liquid matrix. The latent polar diluent has a normal-pressure boiling point temperature below [insert value here]. The initial gelation temperature of the graded resin matrix.

[0043] The ends of the motor windings to be processed are placed in a sealed chamber as porous electromagnetic substrates, and the first negative pressure limit value is alternately established by an air extraction system. With the second micro negative pressure recovery value To expel residual gas adsorbed inside the micropores of the winding insulation cladding; among which, 10 Pa The value is 500 Pa. When determining the specific values ​​of the alternating negative pressure parameters, the control system pre-extracts the apparent design porosity of the insulating cladding in the batch to be processed and calls upon the empirical spectrum of fluid exhaust resistance. Through integral calculation, the system is able to overcome the minimum limiting vacuum required to withstand the maximum capillary gas holding capacity of the cladding structure. A baseline is established, and the absolute value of the small positive pressure difference required to induce reverse airflow scouring and expansion of the residual gas inside the pores is superimposed on this baseline as... The amplitude is restored, thereby enabling dynamic adaptive conversion of the exhaust threshold value for electromagnetic substrates with arbitrary differential configurations.

[0044] A composite reinforcing medium was injected into the sealed chamber, and a three-level gradient pressure sequence increasing from 1.0 kPa to 600 kPa was applied. A sound pressure level of 110 dB and a frequency of [missing information] were then initiated. This is a 35Hz pulsating sound field generator. It utilizes the dynamics of sound field waves to overcome capillary resistance within the gaps, driving the medium to fill the deep gaps at the winding ends. After draining excess liquid medium, a two-stage programmed temperature-curing process is performed on the impregnated winding ends: controlling the Joule heating of the winding conductors, with a first heating rate... Heating the winding ends to the boiling point temperature range of the latent polar diluent and maintaining the temperature for a specified time. At this temperature node, the latent polar diluent at the interface between the winding conductor and the insulating medium undergoes localized vaporization, creating a region with low surface tension within the micropores, pointing from the interface to the resin center. Based on the Marangoni thermocapillary convection generated by the surface tension gradient, micro-flow occurs within the liquid resin matrix, pointing from the bulk center to the interface, driving the fluorinated nanoparticles on the surface to migrate directionally towards the winding insulation boundary and accumulate. The speed is 2.0℃ / min. For 30 minutes, because the intrinsic surface tension of the latent polar diluent is lower than that of the F-grade matrix resin, when it preferentially heats up and vaporizes at the conductor phase interface where the temperature gradient is highest, the low surface tension components in the liquid phase around the phase interface are subsequently locally and rapidly depleted. This causes the surface tension of the remaining liquid phase in the micro-region of the insulating boundary to anomalously jump to the maximum value of the macroscopic system. This induces the Marangoni intrinsic driving force of the fluid spontaneously contracting strongly towards the high surface tension region at the microscopic thermodynamic dimension. This means that the bulk fluid carrying polar nanoparticles can only physically carry out continuous directional convection filling towards the conductor phase interface against the normal temperature gradient, at the second heating rate. Heat to Crosslinking curing temperature plateau and holding time of grade resin matrix This completes the curing and locking of the insulation network; among which The speed is 5.0℃ / min. The curing time is 120 minutes. The winding ends after curing have high density of deep trap charge capture sites at the insulation phase interface. At an altitude of 5000m, they can capture and suppress the migration of space charge, increase the corona initiation voltage and block the evolution path of electrical trees, so that the motor insulation system can maintain operational stability under wide temperature range cyclic stress.

[0045] Example 2: In a special motor insulation performance verification scenario at an altitude of 5000m, the effectiveness of the winding end dielectric reinforcement treatment method for improving motor service life was verified in a physical experimental platform equipped with pressure compensation, acoustic field coupling, and precise temperature control functions. The pressure in the sealed chamber was monitored in real time by a pressure sensor and automatically adjusted within the range of 0kPa to 1000kPa. Simultaneously, a discharge monitoring unit with a sampling frequency of 100MHz and a resolution better than 0.01kV recorded transient corona signals. To recreate the industrial electromagnetic environment, Gaussian white noise with a signal-to-noise ratio of 20dB was superimposed on the acquisition system to determine the acoustic field frequency. When determining the optimal values, a balance must be struck between the activation efficiency of the microrheological properties of the composite reinforcing medium and its ability to maintain the mechanical strength of the winding insulation cladding. When the particle size of the surface fluorinated nanoparticles in the composite reinforcing medium is between 50 nm and 100 nm, sufficient perturbation shear stress is required to break the van der Waals flocculation between the particles. The value should tend towards the lower limit of the range to enhance the cavitation effect of the sound field; in the current simulation conditions, Set to 30Hz; where, The sound field frequency is used as the reference, and the control sample group 1 uses unprocessed samples. The average corona initiation voltage of the resin matrix was measured to be 2.48 kV under a low pressure environment of 53.0 kPa, and dense discharge pulses caused by micro-air gap breakdown were recorded in the waveform monitoring.

[0046] Control group 2 in Only 5.5% surface-fluorinated nanoparticles were incorporated into the resin matrix, without the addition of latent polar diluents or the use of a programmed temperature-rise curing method based on Marangoni thermocapillary convection. Measured data showed that, due to the lack of interfacial directional migration driving force, the uniformity of nanoparticle distribution deep within the winding ends was low, and local electric field distortion weakened the dielectric's withstand voltage. The corona initiation voltage was only 3.05 kV, compared to control sample group three. A latent polar diluent with a mass fraction of 2.2% was incorporated into a high-grade resin matrix, without the addition of nanoparticles. Under the same programmed temperature curing sequence, although the density of the dielectric filling was improved, the corona initiation voltage was 2.82 kV due to the lack of a space charge retardation network. The experimental group treated using the complete method of this invention, through the synergistic effect of surface fluorinated nanoparticles with a molar fraction of 5.5% and latent polar diluent with a mass fraction of 2.2%, achieved complete penetration of the composite reinforcing medium into the micropores of the porous electromagnetic substrate under a gradient pressure sequence and a pulsating sound field with a frequency of 30 Hz. During the curing stage, the Marangoni thermal capillary convection generated by the vaporization of the diluent at the phase interface drove the surface fluorinated nanoparticles to construct a charge retardation layer in situ at the winding insulation boundary. Measured data showed that the experimental group's electrical... The corona initiation voltage was increased to 4.92 kV, representing a 98.39% improvement compared to control group one. Monitoring the residual current flowing through the electrode system revealed that the space charge migration rate decreased by more than 75.3% under Gaussian white noise interference. To verify the rationality of the parameter boundaries, an out-of-range control group four was established, increasing the molar fraction of surface fluorinated nanoparticles to 10.5%. At this point, the initial kinetic viscosity of the composite reinforcing medium increased from 2.5 Pa·s to 13.8 Pa·s, resulting in a 40.2% decrease in the permeability of the medium in the deep layers of the winding end under the same gradient pressure sequence, and particle agglomeration. The corona initiation voltage dropped back to 3.32 kV. This inflection point demonstrates that the molar fraction range of 3.0% to 8.0% is an optimized working window that balances process flowability and dielectric enhancement effect.

[0047] For the mass fraction of the latent polar diluent, an out-of-range control group 5 was established, with its content set at 4.5%. Experimental records showed that excessively high concentrations of diluent generated excessive internal pressure during localized vaporization, leading to the formation of pores with diameters of 10μm to 50μm inside the cured insulation layer, and a drop in corona initiation voltage to 2.65kV. This phenomenon confirms that a mass fraction within the range of 1.5% to 3.0% can induce Marangoni micro-convection without compromising the compactness of the physical structure. Through correlation analysis of the above-mentioned gradient altitude variables and performance indicators, this method consistently maintained the corona initiation voltage within a safe range above 4.5kV as the altitude increased from 1000m to 5000m. These experimental results verify the physical mechanism of constructing a space charge retardation network by inducing interface reconstruction through latent components, demonstrating definite engineering value in improving the end-winding life of high-altitude motors.

[0048] Example 3: When the system faces the challenge of penetration testing due to the insulation cladding thickness exceeding 5mm at the motor winding ends and the overlap rate of single-layer mica tape greater than 50%, a method for improving the service life of the motor by enhancing the dielectric at the winding ends is proposed. This method eliminates the non-uniformity of component distribution by establishing a sound field energy compensation mechanism and an interface driving force calibration procedure. The permeation damping of the composite reinforcing medium within the microscopic gaps of the porous electromagnetic substrate exhibits a non-linear increase with depth, which helps determine the sound pressure level. The system obtains the acoustic attenuation coefficient of the winding end to be processed under the preset impregnation pressure based on the set value. And according to the formula To determine the sound pressure level output from the sealed chamber; among which, For the set output sound pressure level, This is the minimum sound pressure level reference value required for medium seepage. The sound attenuation coefficient is... The characteristic depth of the insulation cladding at the winding end is measured when processing a 6.2mm thick motor stator winding. 2.4dB / mm, selected The calculated sound pressure level setting is 110 dB, which is 95 dB. This sound pressure level is used to compensate for the sound energy loss in the deep porous structure, driving the composite reinforcing medium to overcome capillary resistance and penetrate to the deepest part of the winding cladding under a pulsating sound field of 35 Hz. This basic calculation equation mainly plays a controlling role as the steady-state boundary condition in the initial stage of impregnation. During the dynamic pressure drop penetration cycle, the apparent acoustic impedance will increase exponentially and nonlinearly due to the gradual filling of the insulation pores and the cross-linking of the resin. The control terminal synchronously receives the in-situ sound attenuation ratio signal of the medium fed back by the transducer monitoring the side wall of the sealed chamber. On the basis of maintaining the above linear static compensation value, an additional proportionally amplified acoustic gain constant is calculated to offset the energy drop of the hidden penetration force caused by the nonlinear phase transition.

[0049] During the programmed temperature rise curing stage, to ensure the directional migration of surface fluorinated nanoparticles, the system employs a temperature control method based on viscosity-to-tension ratio, which involves monitoring... Dynamic viscosity of grade resin matrix at the boiling point temperature of latent polar diluent To adjust the first heating rate Surface tension gradient generated by localized vaporization The Marangoni driving force generated must be greater than that generated by The determined viscous frictional resistance, The calculation formula is as follows: ,in, The first heating rate, The system proportionality constant, For surface tension gradient, This refers to the dynamic viscosity of the liquid resin at its boiling point temperature. The average characteristic particle size of the nanoparticles is determined using this physical logic when a modified resin system with a viscosity of 1.2 Pa·s and a characteristic particle size of 80 nm is used. The temperature rise rate is 1.8℃ / min. By controlling heat exchange, the migration rate of surface fluorinated nanoparticles to the winding insulation boundary is ensured to be higher than the viscosity increase rate caused by resin cross-linking. When applying this temperature rise control formula, a one-dimensional spatial reference coordinate system is established along the normal direction perpendicular to the conductor insulation interface. The first-order spatial derivative component of surface tension that is absolutely parallel to the normal axis in the three-dimensional micro-tension vector field is extracted, its multi-dimensional properties are stripped off, and it is forcibly established as the only scalar calculation benchmark in the control formula. By completely eliminating useless dissipative convection vectors parallel to the cross-sectional direction of the insulation layer in the control loop, a deterministic dimensionality reduction rule is established to accurately map the multi-dimensional composite tension field to a single temperature rise rate control command.

[0050] After curing, a dense, layered barrier structure forms at the mica interface at the winding ends. This physical barrier, constructed through thermodynamic matching, enhances the deep-trap charge trapping capability at the phase interface. Test results show that after withstanding 1000 thermal cycling shocks with a temperature difference range of 95°C, the corona initiation voltage fluctuation rate at this location is less than 3.5%, confirming that the interface reconstruction mechanism achieved through acoustic field compensation and tension gradient matching possesses engineering stability under extreme structural constraints. The deep-trap energy level density formed at the insulation interface by the combined action of surface fluorinated nanoparticles and latent polar diluents is... Upgraded to By restricting the transport of space charge at the underlying physical structure level, the insulation service life of the motor windings at an altitude of 5000m meets the design specifications. The absolute value of the deep trap energy level density of the insulation is accurately derived using a high-voltage thermally stimulated depolarization current tester. After the cut-out cured insulation sample is saturated and induced to inject space charge in a constant high-temperature electrostatic field environment, it is immediately transferred to a vacuum liquid nitrogen freezing system to lock the internal trap structure. Subsequently, linear program heating is implemented with a specific temperature compensation step size, and a high-resolution depolarization transient release current spectrum is recorded. The half-peak width parameter and characteristic decay relaxation time constant of the main peak curve of the spectrum are extracted. Finally, the analysis is performed using a pre-set surface isothermal potential decay integral formula. The inverse operation yielded the exact value of the continuous energy level density integral, which characterizes the microscopic physical binding strength of space charge. The calculation logic of the preset surface isothermal potential decay integral analytical formula is as follows: The control terminal first converts the current-time change curve in the depolarization transient release current spectrum into a trap charge release rate function. Using the product of the Boltzmann constant and the real-time absolute temperature as the denominator of the energy level, the product of the logarithmic rate of change of the release current and the characteristic decay relaxation time constant is integrated in the time dimension to calculate the total charge trapped under different thermal activation energies. Then, it is divided by the product of the saturated injection volume of the sample and the basic charge to finally calculate the absolute value of the continuously distributed deep trap energy level density.

[0051] Example 4: In cases involving different batches In the manufacturing of motor stators combining high-grade resin matrix and latent polar diluent, the winding end dielectric reinforcement treatment method to improve motor service life determines process control parameters through physical property benchmark calibration; differential scanning calorimetry is used to determine the effect of latent polar diluent on... Apparent boiling point temperature in grade resin matrix The dynamic surface tension of the latent polar diluent under different temperature gradients was measured using the pendant drop method, thereby calculating the mapping correlation function between temperature and surface tension. ;in, The apparent boiling point temperature. For surface tension, This is the real-time temperature.

[0052] When the impregnation equipment experiences system deviations due to differences in heater thermal response time or temperature sensor placement, this method determines the system proportionality constant using a capillary rise calibration procedure. The numerical values ​​were obtained by placing a test capillary filled with a composite reinforced medium in a controlled temperature field and monitoring the migration front displacement of the fluorinated nanoparticles on the surface under Marangoni micro-convection-driven conditions. By fitting the measured displacement sequence with the analytical solution of the fluid dynamics, the position can be locked. The values ​​of are used to fit and quantize the physical model of material transport in the fluid dynamics interface, and the basic relationships containing all physical variables are called. The calculation extracts the spatial temperature difference measured by the miniature thermocouple sensors arranged in an array along the axial direction of the test capillary, and correlates it with a pre-calibrated mapping function. The surface tension gradient is obtained by multiplying the characteristic derivatives of the surface tension. The mathematical formula involves related parameters covering the dynamic viscosity of the fluid within the test temperature range. And the entire migration time period of the calibration experiment was recorded. For a high-viscosity mixed resin system that is macroscopically opaque and exhibits optical scattering attenuation, a broadband ultrasonic transducer assembly is linearly and equidistantly arrayed along the wall of the test capillary. By continuously sending and receiving high-frequency ultrasonic probes to scan the acoustic impedance transition interface boundary of the fluid phase within the tube, the strong reflected echo flight time delay signal generated by the concentrated leading edge region rich in heavy inorganic particles is continuously converted into definite microscopic spatial relative physical displacement coordinates. These coordinates are then directly loaded into the calculation unit as the measured migration leading edge displacement Lm parameter in the aforementioned derivation algorithm. A unique proportionality coefficient benchmark is obtained through the parameter calculation steps to ensure the first heating rate. The set value compensates for the effective driving force loss caused by the tortuosity of the channels in the micropores of the porous electromagnetic substrate; the nanoparticle concentration distribution range in the thickness direction of the prepared winding end insulation layer is less than 5.0% of the batch fluctuation.

[0053] Example 5: In the scenario of motor stator manufacturing where process adaptation is required for different batches of porous electromagnetic substrates, a winding end dielectric reinforcement treatment method is proposed to improve the service life of the motor. The permeation parameters of the composite reinforcement medium are determined through acoustic characteristic scanning and rheological reference calibration procedures. An ultrasonic transducer is used to perform multi-point transmission measurements at the winding end to be treated under a sealed chamber pressure environment, recording the acoustic energy at the receiving end as a function of transmission depth. The attenuation data resulting from the increase is used to obtain the sound attenuation coefficient through mathematical fitting. Based on the numerical values, test acoustic waves with frequencies ranging from 20Hz to 50Hz and sound pressure levels ranging from 100dB to 120dB were applied to the composite reinforcing medium. The local fluctuation amplitude of the liquid phase system at the inlet of the porous structure was monitored to verify the relationship. Minimum sound pressure level reference value Adaptability to the rheological properties of a specific batch of materials; among which, The characteristic depth of the insulation cladding at the winding end. The sound attenuation coefficient is... For the set output sound pressure level, This is the minimum sound pressure level reference value required for medium seepage.

[0054] against This method investigates viscosity fluctuations in the resin matrix and its latent polar diluent. It employs an interface dynamic response calibration method to determine the control threshold during the programmed temperature-curing stage. A microfluidic testing unit with heating capabilities is used to simulate the microscopic gaps in the windings, and the viscosity of the composite reinforcement medium is recorded at the first heating rate. The bulk concentration of fluorinated nanoparticles migrating to the interface under the influence of the convection front formed at the interface is calculated, and the system proportionality constant is locked. This is then fed back into the industrial production sequence, causing the surface tension gradient generated by localized vaporization to... The generated Marangoni driving force can overcome viscous frictional resistance in resin systems of different viscosities, and the nanoparticle concentration difference distribution in the thickness direction of the prepared stator winding end insulation layer is less than 5.0%.

[0055] Example 6: In a motor stator manufacturing scenario involving batches of surface-fluorinated nanoparticles with different specific surface area distributions, a winding end dielectric reinforcement treatment method to improve motor service life determines the ratio stability of the composite reinforcement medium through an interface adhesion work calibration procedure, and uses a contact angle measuring device to determine the wetting angle between a specific batch of surface-fluorinated nanoparticles and the F-grade resin matrix. According to the formula The interfacial adhesion work was calculated. The value was determined by adjusting the incorporation ratio of surface fluorinated nanoparticles. Maintain at to The optimized range between these parameters ensures that the Marangoni driving force generated in the subsequent curing stage is sufficient to overcome the wetting resistance of the particle surface and induce directional migration. For interfacial adhesion work, - The surface tension of the F-grade resin matrix, - The wetting angle is obtained from the test.

[0056] When performing venting operations on the ends of stator windings with complex curvature distribution and tight interlayer overlap, this method determines the number of venting cycles by monitoring the pressure recovery rate. The pressure sensor was used to record the recovery value of the sealed chamber under the second slight negative pressure. Pressure recovery rate during the maintenance phase And compare it with the preset vacuum gap ratio benchmark. Higher than If the pressure reaches a certain level (Pa / s), an additional exhaust cycle is automatically triggered until the residual gas volume in the system meets the dense filling requirements of the composite reinforcement medium, thereby eliminating the local electric field concentration phenomenon caused by residual micro-gaps in high-altitude environments. The local temperature rise trend of the prepared stator winding end insulation system tends to stabilize under 5000m altitude conditions, verifying the engineering guarantee role of the pre-calibration procedure for the integrity of the insulation structure. This refers to the number of exhaust gas recirculation cycles. This refers to the rate of pressure recovery.

[0057] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit of this application and the scope of protection of this invention, and all of these forms are within the protection scope of this application.

Claims

1. A method for improving the service life of a motor by strengthening the dielectric at the winding ends, characterized in that, Includes the following steps: In step S101, under a vacuum environment with a pressure lower than 50 Pa, surface fluorinated nanoparticles with a molar fraction of 3.0% to 8.0% and a latent polar diluent with a mass fraction of 1.5% to 3.0% are incorporated into the matrix resin, and the composite reinforcing medium is obtained by shear mixing; wherein, the atmospheric pressure boiling point temperature of the latent polar diluent is lower than the initial gel temperature of the matrix resin. Step S102: Place the porous electromagnetic substrate to be treated in a sealed chamber, and alternately establish the first negative pressure limit value and the second micro negative pressure recovery value to expel the adsorbed gas inside the micropores of the porous electromagnetic substrate. Step S103: Inject composite reinforcing medium into the sealed chamber, apply gradient pressure sequence and low-frequency pulsating sound field with a frequency of 20Hz to 50Hz to drive the composite reinforcing medium to penetrate into the deep micropores of the porous electromagnetic substrate. Step S104: Excess liquid phase is drained, and the porous electromagnetic substrate that has been impregnated is subjected to a two-stage programmed temperature rise: the substrate is heated to the boiling point temperature range of the latent polar diluent at a first heating rate and maintained at a constant temperature. The latent polar diluent vaporizes at the phase interface of the porous electromagnetic substrate, generating a surface tension gradient from the phase interface to the center of the matrix resin, driving the surface fluorinated nanoparticles to migrate to the phase interface and accumulate. The substrate is then heated to the crosslinking temperature plateau of the matrix resin at a second heating rate. The crosslinking reaction of the matrix resin is used to anchor the surface fluorinated nanoparticles at the phase interface, constructing a space charge blocking network at the phase interface.

2. The method for improving the service life of a motor by enhancing the dielectric at the winding ends according to claim 1, characterized in that, In step S101, the surface fluorinated nanoparticles include silicon carbide nanoparticles or alumina nanoparticles that have undergone plasma fluorination treatment; the average particle size of the surface fluorinated nanoparticles is 20 nm to 50 nm, and the atomic ratio of fluorine to oxygen on the surface of the surface fluorinated nanoparticles is not less than 0.

8.

3. The method for improving the service life of a motor by enhancing the dielectric at the winding ends according to claim 1, characterized in that, In step S103, the sound pressure level of the low-frequency pulsating sound field is 100dB to 120dB, which is used to break the transient flocculation structure of the surface fluorinated nanoparticles inside the matrix resin.

4. The method for improving the service life of a motor by enhancing the dielectric at the winding ends according to claim 1, characterized in that, In step S103, the gradient pressure sequence includes at least three pressure gradients increasing from 1.0 kPa to 600 kPa, and the duration of each pressure gradient is 30 min to 60 min.

5. The method for improving the service life of a motor by enhancing the dielectric at the winding ends according to claim 1, characterized in that, In step S104, the first heating rate is 1.0℃ / min to 2.0℃ / min; the isothermal maintenance time in the boiling point temperature range is 20min to 40min.

6. The method for improving the service life of a motor by enhancing the dielectric at the winding ends according to claim 1, characterized in that, In step S101, the latent polar diluent includes propylene carbonate or dimethyl phthalate; and the surface tension value of the latent polar diluent at 25°C is lower than that of the matrix resin.

7. The method for improving the service life of a motor by enhancing the dielectric at the winding ends according to claim 1, characterized in that, The space charge retardation network produced in step S104 has a deep trap energy level density at the phase interface that is not lower than .

8. The method for improving the service life of a motor by enhancing the dielectric at the winding ends according to claim 1, characterized in that, After step S103 and before step S104, the method further includes: using dry nitrogen to remove liquid from the surface of the porous electromagnetic substrate, so that the composite reinforcing medium is retained inside the micropores of the porous electromagnetic substrate.

9. The method for improving the service life of a motor by enhancing the dielectric at the winding ends according to claim 1, characterized in that, After step S104 is completed, the method further includes: reducing the temperature at a constant cooling rate to the glass transition temperature range of the composite reinforced medium and maintaining the relaxation plateau to eliminate the microscopic interfacial thermal stress at the phase interface.

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