High-altitude eVTOL motor composite heat dissipation control method and system

Abstract

The present application relates to the technical field of electric vertical take-off and landing aircraft, specifically to a high-altitude eVTOL motor composite heat dissipation control method and system. Through real-time collection of high-altitude air pressure gradient and shear wind speed, three-stage progressive filtering is performed to generate a heat load spectrum line, then through degradation mapping, spatial interference correction and heat flow superposition, a temperature rise offset compensation matrix is generated, and through an equivalent thermal resistance conversion program, a dynamic thermal path topology vector is obtained, finally the vector is converted into a cooling medium micro-flow pre-feed instruction and a phase change energy storage phase interface trigger instruction, which realizes accurate prediction and compensation of the thermal inertia of each propulsion motor in a high-altitude non-uniform flow field environment, reduces the energy consumption of the auxiliary heat dissipation system, and effectively delays the performance degradation rate of the insulation material at high altitude and low air pressure.

Description

Technical Field

[0001] This invention relates to the field of electric vertical takeoff and landing (eVTOL) aircraft technology, specifically to a composite heat dissipation control method and system for a high-altitude eVTOL motor. Background Technology

[0002] With the rapid development of urban air mobility, electric vertical takeoff and landing (eVTOL) aircraft have attracted widespread attention due to their zero emissions, low noise, and maneuverability. However, when eVTOLs operate in high-altitude areas, the thermal management of their propulsion motors faces severe challenges that are drastically different from those in low-altitude plains. The significantly reduced air density at high altitudes leads to a sharp decline in the forced convection heat transfer capacity between the motors and the air. Traditional air-cooling or simple liquid-cooling solutions struggle to maintain the rated heat dissipation flux due to the drift of the convection reference. Simultaneously, during hovering or transitional flight phases, the aerodynamic interference between multiple rotors in eVTOLs is extremely complex. The downwash and vortices generated by adjacent rotors couple and superimpose under low Reynolds number conditions at high altitudes, forming an asymmetric wake interference field. This non-uniform external flow field causes the incoming wind speed and local pressure gradient on the surface of each motor casing to exhibit dynamic and non-linear distribution characteristics, further exacerbating the risk of uneven heat dissipation.

[0003] Mainstream control methods for thermal management of aircraft motors often rely on preset ambient temperature-power mapping models or simple speed feedback regulation. These methods are typically calibrated based on standard sea-level atmospheric conditions or empirical data from low altitudes, failing to adequately consider the thermal time constant drift caused by sudden pressure drops at high altitudes and the degradation of electromagnetic winding insulation performance in thin air. Furthermore, the electromagnetic loss distribution of eVTOL motors under varying operating conditions is strongly correlated with rotor position and thrust distribution strategies, especially at high altitudes where higher speeds are often required to maintain lift motor speeds, leading to more pronounced nonlinear characteristics of winding copper and iron losses. Current technology lacks a method to comprehensively quantify and feed forward the thermal coupling relationship between external thin-air aerodynamic disturbances, internal electromagnetic loss transients, and the casing thermal capacitance, and then feed this information to the cooling actuator. Therefore, a thermal management strategy is urgently needed that can accurately calculate the topological changes of each motor's specific thermal path and perform dynamic feedforward-feedback composite control of the micro-flow rate of the cooling medium and the phase change energy storage interface to address the problems of insufficient heat dissipation, excessive energy consumption, and insulation life degradation in high-altitude eVTOL motors. Summary of the Invention

[0004] To overcome the problems of existing technologies being unable to adapt to the convection drift of thin air at high altitudes and the interference of complex rotor wakes, resulting in low heat dissipation control accuracy, high energy consumption, and difficulty in suppressing the rate of increase of thermodynamic entropy of insulating materials, this invention provides a composite heat dissipation control method and system for high-altitude eVTOL motors. This method achieves accurate prediction and compensation of the thermal inertia of each propulsion motor in a non-uniform flow field environment at high altitudes, effectively slowing down the performance degradation rate of insulating materials under low air pressure at high altitudes while reducing the energy consumption of the auxiliary heat dissipation system.

[0005] The technical solution of this application specifically includes: According to one aspect of this application, a composite heat dissipation control method for a high-altitude eVTOL motor is provided, comprising: The raw signals under high-altitude flight conditions are acquired in real time, and the raw signals are decoupled by a three-level progressive filtering layer. The results of the three-level filtering are superimposed to generate independent initial thermal load spectra of each motor. Based on the initial heat load spectrum, three-layer logic calculations are performed sequentially: heat load degradation mapping, spatial interference correction, and heat flux density superposition, outputting a temperature rise offset compensation matrix specific to each motor. The equivalent thermal resistance conversion program is started for the temperature rise offset compensation matrix. The equivalent thermal resistance conversion program is executed in the progressive order of stator yoke circumferential thermal diffusion identification, air gap equivalent thermal conductivity dynamic reconstruction, and casing and environment thermal capacity coupling mapping. The equivalent thermal resistance conversion program obtains the dynamic thermal path topology vector that reflects the current thermal time constant difference of each motor. The dynamic thermal path topology vector is converted into a duty cycle feedforward control command for the cooling medium micro-flow regulating valve and a phase interface shift trigger control command for the phase change energy storage unit according to the thermal equilibrium state space mapping relationship. The heat dissipation actuator is driven to act according to the control command. The partial discharge initiation voltage and the rate of change of the surface temperature of the winding insulation layer are monitored in the high-altitude, thin air environment. If the rate of change exceeds the safety entropy increase threshold derived from the temperature rise offset compensation matrix, the equivalent thermal conductivity of the air gap is corrected in reverse, and the process is repeated to suppress the rate of increase of the thermodynamic entropy of the insulation material.

[0006] As a further option of the method of the present invention, the decoupling process of the three-stage progressive filter layer includes: The first-stage filtering layer uses an adaptive high-pass filter built based on the international standard atmospheric model to remove the convective reference drift caused by the sudden drop in atmospheric density due to altitude changes. The second-level filtering layer constructs a narrowband bandpass filter bank based on the blade passage frequency and second harmonic frequency of adjacent rotors. Combined with wavelet packet transform time-frequency decomposition, it separates the asymmetric aerodynamic interference components generated by the wake interference of adjacent rotors and defines the vorticity amplitude characteristic to characterize the intensity of wake interference. The third-level filtering layer processes the total electromagnetic loss power obtained from the equivalent circuit model of the motor through Kalman filtering, and extracts the transient characteristics of the internal electromagnetic loss of the motor under the current differential thrust distribution strategy.

[0007] As a further option of the method of the present invention, the generation of the initial spectral lines of the thermal load includes: The signal after the first stage of filtering, representing the convection reference correction, the asymmetric aerodynamic interference component of the second stage of filtering output, and the electromagnetic loss transient characteristics of the third stage of filtering output are respectively mapped to the comparable interval through a normalization function; Based on the current flight phase and the motor operating point, fusion weights that meet the normalization conditions are dynamically allocated, and a weighted superposition is used to generate a fusion weight for the first... The initial spectral line of the heat load of the trolley motor as a function of time is expressed as: In the formula, Indicates the first TE Connectivity at all times Initial spectral value of heat load; , , These are the signals output from the first, second, and third stages of filtering, respectively. , , For standardized functions; , , It is to satisfy The dynamic weighting coefficients.

[0008] As a further option of the method of the present invention, the formation of the temperature rise offset compensation matrix includes: The heat load degradation mapping layer defines a degradation coefficient that characterizes the degree of decline in convective heat transfer capacity. The calculation formula is: In the formula, It is a function of the current effective Nusselt number based on the heat load spectral line; The rated Nusselt number under sea-level reference conditions, and the attenuation coefficient. The value range is between [0,1], and the average value of the overall motor attenuation coefficient and the variance reflecting the surface non-uniformity are statistically analyzed; The spatial interference correction layer introduces an asymmetric wake interference angle constructed from the second-stage filter vorticity amplitude and the phase difference between rotors. Based on the correction function containing vorticity amplitude, asymmetric wake interference angle and calibration coefficient, the average attenuation coefficient is spatially compensated to obtain the spatially corrected heat dissipation capacity attenuation coefficient. The heat flux density superposition layer uses the spatially corrected heat dissipation capacity attenuation coefficient as a spatial modulation function, and performs nonlinear convolution operation with the winding heat flux density distribution allocated according to the prior spatial weight of the finite element model to generate a temperature rise offset compensation matrix.

[0009] As a further option of the method of the present invention, the circumferential thermal diffusion identification step of the stator yoke is as follows: The submatrix corresponding to the geometric region of the stator yoke is extracted from the temperature rise offset compensation matrix, and the temperature gradient distribution of the submatrix along the circumferential direction is calculated by the discrete gradient operator based on the central difference method. A circumferential thermal diffusivity factor is defined, which is inversely proportional to the root mean square of the circumferential gradient magnitude. It is calculated by taking the root mean square of the gradient magnitude over the entire circumference and is used to quantify the non-uniformity of heat accumulation in the yoke caused by external asymmetric heat dissipation.

[0010] As a further option of the method of the present invention, the dynamic reconstruction step of the equivalent thermal conductivity of the air gap includes: The Knudsen number, which characterizes the rarefaction of a gas, is determined by the ratio of the mean free path of air molecules to the characteristic length of the air gap. In response to the decrease in air pressure at high altitudes leading to an increase in the Knudsen number and entry into the transition flow region, a modified interpolation formula is used to dynamically reconstruct the equivalent thermal conductivity of the air gap, expressed as: In the formula, The equivalent thermal conductivity of the air gap is... The standard thermal conductivity of air at the current temperature; It is a Prandtl number; This is a comprehensive coefficient. Knudsen number, defined as the mean free path of air molecules With air gap characteristic length The ratio of .

[0011] As a further option of the method of the present invention, the thermal capacity coupling mapping step between the casing and the environment is as follows: Calculate the effective heat capacity of the external air, which is determined by the product of air density, specific heat capacity at constant pressure, and effective heat transfer volume. The effective heat capacity of the external air is equal to the product of air density, specific heat capacity at constant pressure, and effective heat transfer volume. Based on the connection between the equivalent heat capacity of the motor housing and the effective heat capacity of the external air through a thermal resistance network, the dominant thermal time constant of the i-th motor is calculated, and the expression is: In the formula, The thermal time constant, This is the equivalent heat capacity of the motor housing; The effective heat capacity of the outside air; The total equivalent thermal resistance from the winding to the environment; The dynamic thermal path topology vector is generated by combining the circumferential thermal diffusivity, the air gap equivalent thermal conductivity, the total equivalent thermal resistance, and the dominant thermal time constant.

[0012] As a further option of the method of the present invention, the step of converting the dynamic thermal path topology vector into a duty cycle feedforward control command for the cooling medium micro-flow regulating valve according to the thermal equilibrium state space mapping relationship includes: Using the thermal time constant and total equivalent thermal resistance in the dynamic thermal path topology vector as indexes, the optimal control multidimensional lookup table constructed offline with the goal of minimizing the total energy consumption of the auxiliary heat dissipation system is queried to obtain the duty cycle feedforward value of the micro-flow regulating valve. In response to the predicted decrease in thermal time constant, the duty cycle of the micro-flow regulating valve in the cooling circuit is increased in advance to increase the flow rate of coolant to the corresponding motor in order to suppress temperature spikes.

[0013] As a further option of the method of the present invention, the step of converting the dynamic thermal path topology vector into a phase interface shift trigger control command of the phase change energy storage unit according to the thermal equilibrium state space mapping relationship includes: When a positive heat flux peak is predicted based on the dynamic thermal path topology vector, a positive current signal is output to drive the micro thermoelectric cooler close to the encapsulation wall of the phase change material to work in heating mode, causing the solid-liquid interface to move towards the solid region to absorb the latent heat of fusion. When the predicted heat load decreases, the output reverse current signal causes the liquid-solid interface to move towards the liquid region to release latent heat, and the phase interface moving rate is approximately proportional to the applied current density.

[0014] As a further option of the method of the present invention, the monitoring of the partial discharge initiation voltage in a high-altitude, thin-air environment includes: The weak electromagnetic pulse signal generated by partial discharge is captured by an ultra-high frequency antenna or high frequency current transformer installed in the high-voltage junction box or winding end of the motor. Based on the amplitude, phase distribution, and pulse repetition rate of the captured signal, combined with the current air pressure and motor voltage, the partial discharge initiation voltage is estimated online, and the insulation safety margin is obtained by comparing it with the current peak value of the motor phase voltage.

[0015] As a further option of the method of the present invention, the step of reversely correcting the equivalent thermal conductivity of the air gap if the rate of change exceeds the safety entropy increase threshold derived from the temperature rise offset compensation matrix includes: The rate of temperature change on the surface of the winding insulation layer was measured using a distributed fiber optic grating temperature sensor array. The safe entropy increase threshold is calculated based on a material aging kinetic model, using the following formula: In the formula, For the safety entropy increase threshold, The activation energy of insulating materials; Boltzmann's constant; For reference temperature; The maximum operating temperature allowed by the insulation class; The safety factor function has values ​​in the range [0,1], derived from the temperature rise offset compensation matrix. The maximum temperature rise prediction value is dynamically adjusted. When the absolute value of the measured temperature change rate exceeds the safe entropy increase threshold, the equivalent thermal conductivity of the air gap is multiplied by a correction factor of less than 1 and fed back to the equivalent thermal resistance conversion program for re-execution, so as to forcibly enhance the cooling response and suppress the rate of increase of the thermodynamic entropy of the insulating material within the safe threshold.

[0016] Another aspect of this application provides a high-altitude eVTOL motor composite heat dissipation control system, the system comprising: The multi-physics signal acquisition and decoupling module is used to acquire raw signals in real time under high-altitude flight conditions, decouple the raw signals by a three-level progressive filtering layer, and superimpose the three-level filtering results to generate independent initial thermal load spectra of each motor. The temperature rise offset compensation matrix generation module is used to perform three-level logic calculations based on the initial heat load spectrum, including heat load degradation mapping, spatial interference correction, and heat flux density superposition, and output the temperature rise offset compensation matrix specific to each motor. The dynamic thermal path topology vector acquisition module is used to start the equivalent thermal resistance conversion program for the temperature rise offset compensation matrix. The equivalent thermal resistance conversion program is executed in the progressive order of stator yoke circumferential thermal diffusion identification, air gap equivalent thermal conductivity dynamic reconstruction, and casing and environment thermal capacity coupling mapping. The dynamic thermal path topology vector reflecting the current thermal time constant difference of each motor is obtained through the equivalent thermal resistance conversion program. The feedforward control command generation and execution module is used to convert the dynamic thermal path topology vector into the duty cycle feedforward control command of the cooling medium micro-flow regulating valve and the phase interface shift trigger control command of the phase change energy storage unit according to the thermal equilibrium state space mapping relationship, and drive the heat dissipation actuator to act according to the control command. The insulation condition monitoring and feedback correction module is used to monitor the partial discharge initiation voltage and the temperature change rate of the winding insulation layer surface in a high-altitude, thin air environment. If the change rate exceeds the safety entropy increase threshold derived from the temperature rise offset compensation matrix, the equivalent thermal conductivity of the air gap is corrected in reverse, and the process is re-executed to suppress the rate of increase of the thermodynamic entropy of the insulation material.

[0017] The beneficial effects of this application are as follows: Addressing the shortcomings of traditional sea-level empirical models in handling the severe uneven heat dissipation caused by reference drift in the thin air convection at high altitudes and asymmetric wake interference, this invention completely eliminates thermal characterization distortion caused by the coupling of sudden environmental changes and complex operating conditions through multi-physics field three-level progressive filtering decoupling and dynamic thermal path topology reconstruction. It accurately maps multidimensional non-uniform heat flow into feedforward control commands for the duty cycle of micro-flow regulating valves and the shift of the phase change energy storage phase interface, achieving advanced suppression of temperature spikes with low energy consumption. At the same time, it innovatively couples picocoulomb-level partial discharge monitoring with a temperature change rate safety threshold based on the thermodynamic entropy increase principle for closed-loop feedback correction, breaking through the limitation of existing technologies in lacking active defense against insulation degradation at high altitudes. Ultimately, it achieves high-precision, extremely low-energy consumption, and active protection of insulation life in the heat dissipation control of high-altitude eVTOL propulsion motors. Attached Figure Description

[0018] Figure 1 A schematic diagram of the overall heat dissipation control method for high-altitude eVTOL motors; Figure 2 S100 flowchart of composite heat dissipation control method for high-altitude eVTOL motor; Figure 3 S200 flowchart of composite heat dissipation control method for high-altitude eVTOL motor; Figure 4 S300 flowchart of composite heat dissipation control method for high-altitude eVTOL motor; Figure 5 S400 flowchart of composite heat dissipation control method for high-altitude eVTOL motor; Figure 6 S500 flowchart of composite heat dissipation control method for high-altitude eVTOL motor; Figure 7 , Figure 8 , Figure 9 , Figure 10 , Figure 11 and Figure 12 This is a diagram of the operating interface of the high-altitude eVTOL motor composite heat dissipation control system. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] The core theoretical foundation of this invention is based on the theory of rarefied gas dynamics, the theory of thermal resistance networks in heat transfer, and the theory of nonlinear system identification. By combining the correlation of rarefied air convection heat transfer to verify the physical laws of the thermal boundary layer, and by identifying and subdividing the aerodynamic interference distortion region based on the topological structure and continuity principle of the rotor wake vortex field, the local thermal resistance mapping function is constrained using the Lipschitz condition, and the principle of thermodynamic entropy increase is introduced for safety verification. Ultimately, a complete method is formed, from multi-physics field signal decoupling, spatial heat flow nonlinear compensation, dynamic thermal path topology reconstruction to feedforward-feedback composite control command generation, achieving high-precision, low-energy consumption, and active protection of insulation life in the heat dissipation control of high-altitude eVTOL propulsion motors.

[0021] The specific embodiments of the present invention will be described in detail below.

[0022] Example 1: Please see Figure 1 , Figure 1 This diagram illustrates an overall flowchart of a composite heat dissipation control method for a high-altitude eVTOL motor according to an embodiment of the present invention. The method includes: S100: Multi-physics field signal acquisition and three-level progressive filtering decoupling in high-altitude, thin environment to generate initial thermal load spectrum; S200: Based on the three-layer logic calculation of the heat load spectrum, a temperature rise offset compensation matrix is ​​generated; S300: The equivalent thermal resistance conversion program is executed to obtain the dynamic thermal path topology vector; S400: Feedforward control command generation and execution based on thermal equilibrium state space mapping; S500: Insulation status monitoring and feedback correction based on safety entropy increase threshold.

[0023] The specific plan is as follows: The S100 decouples the raw signals collected in real time by miniature barometric sensors, hot-wire anemometers, and infrared radiometers deployed around each propulsion motor during eVTOL flight through a three-stage progressive filtering layer. The first-stage filtering layer removes the convective reference drift caused by the sudden drop in atmospheric density due to altitude changes; the second-stage filtering layer separates the asymmetric aerodynamic interference components generated by the wake interference of adjacent rotors; and the third-stage filtering layer extracts the transient characteristics of the electromagnetic losses inside the motors under the current differential thrust distribution strategy. The results of the three-stage filtering are superimposed to generate independent initial thermal load spectra for each motor, thereby eliminating the distortion in thermal load characterization caused by environmental interference and operating condition coupling.

[0024] Please refer to Figure 2 , Figure 2 This paper presents a detailed flowchart of S100 in an exemplary high-altitude eVTOL motor composite heat dissipation control method of this application. S100 specifically includes: S110: In this embodiment, when the eVTOL aircraft enters the high-altitude flight envelope, the multi-source sensor array deployed on each propulsion motor nacelle structure is activated and enters the high-frequency synchronous sampling mode.

[0025] In one possible implementation of this embodiment, the step of synchronous real-time acquisition includes: S111: Miniature dynamic air pressure sensors arranged in a circumferential array on the casing of each propulsion motor, which collect instantaneous static pressure in real time and calculate the original air pressure gradient through spatial difference.

[0026] S112: Hot-wire anemometer probes are arranged on the windward and sidewind sides of the motor nacelle. After introducing a rarefied gas correction coefficient, the corrected incoming flow shear velocity is obtained.

[0027] S113: A thermopile-type radiative heat flux sensor installed on the non-wind-facing area of ​​the inner wall of the motor nacelle, which obtains the background radiative heat flux after cold junction compensation and ambient temperature correction.

[0028] S120: In this embodiment, the first-stage filtering layer is specifically designed to remove the slow and significant drift of the convective heat transfer baseline caused by changes in atmospheric density due to variations in flight altitude. If this drift is not removed, the minute features of subsequent aerodynamic interference and electromagnetic losses will be submerged in the trend of environmental changes, leading to feature extraction failure.

[0029] In one possible implementation of this embodiment, the step of stripping the convection reference drift includes: S121: Obtain current flight altitude from the aircraft's atmospheric data computer. and atmospheric static temperature The ratio of the current air density to the standard sea-level density is calculated based on the international standard atmospheric model. The baseline rate of change of the convective heat transfer coefficient due to density changes is then calculated using the density ratio from the standard atmospheric model and empirical heat transfer correlations.

[0030] S122: Based on the baseline rate of change of the convective heat transfer coefficient calculated in S121, a digital high-pass filter with a variable cutoff frequency is constructed. When the aircraft is in a rapid climb or descent phase, and the density changes drastically, the cutoff frequency is appropriately increased to prevent filter saturation. When in the cruise phase, and the density changes gradually, the cutoff frequency is reduced to an extremely low value. The original air pressure gradient and incoming shear wind speed collected in S110 are passed through the above adaptive high-pass filter to output the first-stage filtered signal after filtering out the gradual trend of atmospheric density change.

[0031] S123: The collected background radiative heat flow is processed in the same way. The radiation reference drift caused by the above-mentioned ambient temperature change is also removed by the first-stage high-pass filter, so that the radiative heat flow signal retains only the fast-changing component related to the temperature change of the motor itself.

[0032] S130: In this embodiment, the second-stage filtering layer separates signals to address the complex near-field aerodynamic interference unique to eVTOL. In a multi-rotor configuration, the downwash and tip vortices generated by adjacent rotors spatially superimpose and interfere with each other, resulting in strong unsteady and asymmetric characteristics in the airflow passing over the target motor housing. The purpose of this step is to separate the specific frequency band interference component caused by wake interference from the signal filtered by the first stage.

[0033] In one possible implementation of this embodiment, the step of separating the asymmetric aerodynamic disturbance components includes: S131: The system obtains the real-time rotational speed and number of blades for each rotor from the flight controller. Rotor speed is... The number of blades is indicated by... This indicates that the blade passage frequency of each rotor and its second harmonic frequency are calculated using the rotor speed and the number of blades. Based on the blade passage frequencies and their second harmonic frequencies of all adjacent rotors, a set of narrowband bandpass filters with center frequencies of the aforementioned frequencies is designed.

[0034] S132: Wavelet packet transform is used to perform time-frequency decomposition on the pressure gradient and incoming shear wind speed after the first-stage filtering. The signal is decomposed into several sub-frequency bands.

[0035] S133: For each decomposed sub-band, by analyzing the phase difference of the same sub-band signals on different motor nacelles, the propagation direction and velocity of the wake vortex structure in space are inferred. Reconstructing the signals of each sub-band yields the asymmetric aerodynamic interference components in the time domain. Simultaneously, a vorticity amplitude characteristic quantity is defined, using... This characteristic quantity is obtained by taking the square root of the weighted square of the energy of each relevant sub-band. The weighting coefficients of each sub-band are pre-calibrated based on the contribution of each band to heat dissipation. (Vortex amplitude) It quantitatively characterizes the severity of wake interference; the larger the value, the stronger the wake disturbance at the current location of the motor, and the more significant the impact on heat dissipation.

[0036] S140: In this embodiment, the third-stage filter layer focuses on the electromagnetic heat source characteristics inside the motor. During high-altitude flight, in order to maintain lift or perform maneuvers, the flight control system adjusts the thrust distribution of each motor in real time, causing rapid changes in current and magnetic field, resulting in transient fluctuations in copper and iron losses.

[0037] In one possible implementation of this embodiment, the step of extracting transient electromagnetic loss features includes: S141: The instantaneous values ​​of the three-phase current, rotor electrical angle, and speed are read in real time from the electronic speed controller of each motor via the data bus. The instantaneous copper loss power is obtained at the current moment based on the motor's equivalent circuit model. The instantaneous iron loss power is obtained by looking up a table based on the speed and a pre-calibrated iron loss model. The total electromagnetic power loss is the sum of the copper loss power and the iron loss power.

[0038] S142: The total electromagnetic loss power calculated in S141 is used for prediction and update iteration steps of Kalman filtering to obtain a smooth loss power estimate and its rate of change. The above results are the transient characteristics of electromagnetic loss.

[0039] S150: In this embodiment, the signals after the above three-stage filtering are organically superimposed to generate an initial spectrum unique to each motor that can truly reflect its current thermal load status and potential.

[0040] In one possible implementation of this embodiment, the step of generating the initial spectral lines of the thermal load includes: S151: The signal after the first-stage filtering, representing the convection reference correction, the asymmetric aerodynamic interference component of the second-stage filtering output, and the electromagnetic loss transient characteristics of the third-stage filtering output are standardized to map their value ranges to comparable intervals.

[0041] S152: Dynamically allocate fusion weights based on the current flight phase and motor operating point. Generate an initial thermal load spectrum through weighted superposition; this initial thermal load spectrum is specific to the [flight phase / stage]. The expression for a curve of the trolley motor changing with time is: In the formula, Indicates the first TE Connectivity at all times Initial spectral value of heat load; , , These are the signals output from the first, second, and third stages of filtering, respectively. , , For standardized functions; , , It is to satisfy The dynamic weighting coefficients.

[0042] In a composite heat dissipation control method for high-altitude eVTOL motors, S200 is based on the initial independent thermal load spectra of each motor generated by S100. The system sequentially performs three-layer calculations: thermal load degradation mapping, spatial interference correction, and heat flux density superposition. Finally, it outputs a multi-dimensional temperature rise offset compensation matrix, which is used to accurately describe the non-uniform heat dissipation compensation requirements of each motor due to differences in spatial location and operating status.

[0043] Please refer to Figure 3 , Figure 3 This application illustrates a detailed flowchart of step S200 in an exemplary composite heat dissipation control method for a high-altitude eVTOL motor. Step S200 includes: S210: In this embodiment, the heat load degradation mapping step will convert the dimensionless heat load spectrum output by S150. It can be converted into a specific physical quantity, namely a coefficient that characterizes the degree of attenuation of convective heat transfer capacity relative to the rated state at sea level.

[0044] In one possible implementation of this embodiment, the step of heat load degradation mapping includes: S211: Establish from The mapping relationship to the convective heat transfer attenuation rate. In high-altitude, thin-water environments, the weakening of convective heat transfer is directly reflected in the decrease in the Nusselt number. The attenuation coefficient is defined using... The calculation formula is as follows: In the formula, It is a function of the current effective Nusselt number of the heat load spectral line, and usually appears as an S-shaped curve that decreases monotonically as the heat load spectral line increases; The rated Nusselt number under sea-level reference conditions, and the attenuation coefficient. The value of is in the range [0,1]. When it is close to 1, it indicates that the current heat dissipation capacity is close to the rated level at sea level; when When the value approaches 0, it indicates that the heat dissipation capacity is almost completely lost.

[0045] S212: For the first The attenuation coefficient values ​​calculated from all discrete measuring points on the surface of the motor are spatially statistically analyzed to obtain a scalar average value representing the overall convective heat transfer degradation of the motor, and a variance reflecting surface non-uniformity. The average value will serve as the basic input for subsequent steps, while the variance will serve as an auxiliary indicator for judging the degree of heat dissipation non-uniformity.

[0046] S220: In this embodiment, the spatial interference correction step performs a secondary correction on the average attenuation coefficient obtained in S210 to reflect the unique effects of the motor at different installation positions on the arm or fuselage caused by the interference of adjacent rotor wakes.

[0047] In one possible implementation of this embodiment, the spatial interference correction step includes: S221: Vortex amplitude output using the second-stage filter of S130 Using the phase difference information between each rotor, a vector characterizing the direction and intensity of the asymmetric wake impact is constructed. The asymmetric wake interference angle is defined using... The asymmetric wake interference angle is defined as the angle between the wake impact direction vector and the normal vector to the motor housing surface. The closer to zero degrees, the more directly the wake impacts the motor, which is beneficial for heat dissipation. Interference angle. The closer to or greater than 90°, the more likely the wake is to brush against or move away from the motor, which is detrimental to heat dissipation.

[0048] S222: Computational space-corrected heat dissipation capacity attenuation coefficient The calculation formula is as follows: In the formula, The first one obtained for S212 The average attenuation coefficient of the motor; The vorticity amplitude calculated for S133; It is an asymmetric wake interference angle; It is a positive calibration coefficient.

[0049] S230: In this embodiment, the heat flux density superposition step is the final step of the three-layer calculation, which couples the previously obtained heat dissipation capacity attenuation coefficient with the actual heat flux generated inside the motor. The purpose of the above calculation is to simulate the process of heat conduction and accumulation inside the solid components of the motor under non-uniform heat dissipation conditions, and finally output a matrix that can predict the temperature rise offset of different parts.

[0050] In one possible implementation of this embodiment, the step of superimposing heat flux densities includes: S231: Based on the prior knowledge of the finite element model of the motor, the total electromagnetic loss power calculated in S140 is distributed to each discrete node of the motor stator winding according to the preset spatial weights to obtain the heat flux density distribution.

[0051] S232: The heat dissipation capacity attenuation coefficient calculated from S220 As a spatial modulation function, it is nonlinearly convolved with the heat flux density distribution. The result of the convolution operation is the [missing information - likely a specific function or method]. The temperature rise offset compensation matrix of the TE Connectivity generator is used. express.

[0052] In a composite heat dissipation control method for a high-altitude eVTOL motor, the temperature rise offset compensation matrix output by S300 to S200 is used. The equivalent thermal resistance conversion program is initiated. The program executes in a progressive order: stator yoke circumferential thermal diffusion identification, dynamic reconstruction of air gap equivalent thermal conductivity, and thermal capacity coupling mapping between the casing and the environment. Ultimately, it obtains a dynamic thermal path topology vector that reflects the current thermal time constant differences of each motor, providing an accurate thermal inertia model for control command generation.

[0053] Please refer to Figure 4 , Figure 4 This application illustrates a detailed flowchart of step S300 in an exemplary composite heat dissipation control method for a high-altitude eVTOL motor. Step S300 includes: S310: In this embodiment, the stator yoke is the main channel for heat conduction from the windings to the housing inside the motor. Due to the asymmetry of external aerodynamic interference, the heat diffusion capacity varies at different circumferential positions of the stator yoke. This step aims to identify and quantify these differences.

[0054] In one possible implementation of this embodiment, the step of identifying circumferential thermal diffusion in the stator yoke includes: S311: From the temperature rise offset compensation matrix The submatrix corresponding to the geometric region of the stator yoke is extracted. The gradient distribution of the submatrix along the circumferential direction is calculated using a discrete gradient operator based on the central difference method. The magnitude of the gradient directly reflects the non-uniformity of heat accumulation in the yoke due to external asymmetric heat dissipation.

[0055] S312: Since heat flux density is directly proportional to the temperature gradient, the thermal resistance to circumferential thermal diffusion is inversely proportional to the magnitude of the circumferential gradient. Define a circumferential thermal diffusivity factor, using... This means that it is calculated by taking the root mean square of the gradient magnitude over the entire circumference.

[0056] S320: In this embodiment, the air gap between the motor stator and rotor is a key thermal resistance element in the thermal circuit. At high altitudes, the air density in the air gap decreases, and its thermal conductivity changes significantly, so the sea level constant can no longer be used as a substitute.

[0057] In one possible implementation of this embodiment, the step of dynamically reconstructing the equivalent thermal conductivity of the air gap includes: S321: The equivalent thermal conductivity of the air gap is closely related to the rarefaction of the gas, and is characterized by the Knudsen number. It is expressed as the mean free path of air molecules. With air gap characteristic length The ratio, i.e. Molecular mean free path It is inversely proportional to air pressure and directly proportional to temperature, and can be obtained from formulas in gas dynamics theory. Air gap characteristic length. This refers to the distance between the stator and rotor. At high altitudes, air pressure decreases. Enlargement, leading to It increases significantly, entering the transition flow region or even the free molecular flow region.

[0058] S322: In the transition flow region, the equivalent thermal conductivity of the gas deviates significantly from the theoretical value for the continuous medium. A modified interpolation formula is used for dynamic reconstruction, and the equivalent thermal conductivity of the air gap is calculated using... The calculation formula is as follows: In the formula, The standard thermal conductivity of air at the current temperature; It is a Prandtl number; This is a comprehensive coefficient, related to the thermal adaptability coefficient and specific heat capacity ratio.

[0059] S330: In this embodiment, the final step is to establish a dynamic thermal coupling relationship between the motor housing heat capacity and the changing external environment. The external environment not only affects the heat dissipation thermal resistance, but also the effective heat capacity involved in heat exchange.

[0060] In one possible implementation of this embodiment, the step of thermal capacity coupling mapping between the casing and the environment includes: S331: Calculate the effective heat capacity of the external air. The effective heat capacity of the external air is equal to the product of the air density, the specific heat capacity at constant pressure, and the effective heat transfer volume.

[0061] S332: Establish a thermal capacity coupling model between the motor housing and the environment, connecting the thermal capacity of the motor housing with the effective thermal capacity of the external air through a thermal resistance network. The current dominant thermal time constant is used... The calculation formula is as follows: In the formula, This is the equivalent heat capacity of the motor housing; The effective heat capacity of the external air calculated for S331; This represents the total equivalent thermal resistance from winding to ambient after considering the results of S310 and S320. Thermal time constant. It reflects the first The core indicator of a TECH appliance's heating or cooling rate. When A smaller value means the system has low thermal inertia, responds quickly to thermal disturbances, and requires a faster cooling response. When When the temperature is large, the system has high thermal inertia and the temperature rise changes gradually.

[0062] S340: In this embodiment, the parameters that characterize the properties of each link in the thermal circuit obtained from the aforementioned steps are set into a structured vector.

[0063] In one possible implementation of this embodiment, the step of generating the dynamic thermal path topology vector includes: S341: Circumferential thermal diffusivity Air gap equivalent thermal conductivity Total equivalent thermal resistance Dominant thermal time constant Other auxiliary parameters are combined in a predetermined order to form the first The dynamic thermal path topology vector of the TE Connectivity generator is used express.

[0064] In a composite heat dissipation control method for a high-altitude eVTOL motor, S400 uses the dynamic thermal path topology vector generated by S300. As input, the preset thermal equilibrium state space mapping relationship is used to convert it into feedforward control commands that can directly drive the action of the heat dissipation actuator.

[0065] Please refer to Figure 5 , Figure 5 This application illustrates a detailed flowchart of S400 in an exemplary high-altitude eVTOL motor composite heat dissipation control method. S400 includes: S410: In this embodiment, during the offline phase, a system identification and optimization algorithm has been used to establish the thermal path topology vector. The state-space mapping relationship from the optimal heat dissipation control command.

[0066] In one possible implementation of this embodiment, the state space mapping step includes: S411: The control objective is to minimize the total energy consumption of the auxiliary cooling system while satisfying the temperature constraints of each motor. The state variable is the dynamic thermal path topology vector. The control variables include the duty cycle of the cooling medium flow regulating valve and the phase interface shift trigger signal of the phase change energy storage unit.

[0067] S412: Solving the above state-space optimal control problem yields a multidimensional lookup table. The lookup table uses the thermal path topology vector... Key elements, especially the thermal time constant Total equivalent thermal resistance Use the index to output the corresponding feedforward control command.

[0068] S420: In this embodiment, for the liquid cooling circuit of each motor, the system outputs a feedforward duty cycle command according to the lookup table. The above command actively adjusts the coolant flow rate before the temperature sensor detects the temperature rise.

[0069] In one possible implementation of this embodiment, the steps of the duty cycle feedforward instruction include: S421: During online operation, based on the real-time calculated thermal path topology vector Query the lookup table established by S412 to obtain the first... Duty cycle feedforward value of the micro-flow regulating valve in the cooling circuit of the trolley motor.

[0070] S422: The control unit generates a pulse width modulation signal to drive a high-speed solenoid valve or proportional valve to operate with the queried duty cycle, precisely controlling the flow direction. Coolant flow rate of the motor. When the motor's thermal time constant is predicted. A smaller duty cycle means that when the temperature rises rapidly, the duty cycle increases earlier, increasing the cooling flow and thus effectively suppressing temperature spikes.

[0071] S430: In this embodiment, for the transient operating conditions of the eVTOL motor with short-term high torque and high loss, the phase change energy storage unit is used to smooth out heat flux peaks. This step actively controls the migration speed of the solid-liquid interface of the phase change material through control commands to control the composite heat dissipation of the high-altitude eVTOL motor.

[0072] In one possible implementation of this embodiment, the steps of phase interface shift control include: S431: The phase interface shift trigger signal is a weak current signal with variable amplitude and polarity. When based on the thermal circuit topology vector... When a positive heat flux spike is predicted, such as when a rapid ramp command is issued, a positive current signal is output to drive a miniature thermoelectric cooler close to the encapsulation wall of the phase change material into heating mode. This causes the solid-liquid interface to shift towards the solid state, absorbing a large amount of latent heat of fusion, thus achieving the peak-shaving effect of the heat flux spike. Conversely, when a decrease in heat load is predicted, a reverse current is output to cause the liquid-solid interface to shift towards the liquid state, releasing latent heat.

[0073] S432: The control unit outputs the corresponding analog voltage or digital command according to the lookup table, driving the constant current source circuit to generate the required microcurrent, which is then applied to the trigger electrode of the phase change energy storage unit. The phase interface migration rate of the phase change material is approximately proportional to the applied current density; by controlling the current magnitude, precise feedforward control of the latent heat absorption or release rate can be achieved.

[0074] In a composite heat dissipation control method for high-altitude eVTOL motors, the S500 is specifically designed to address the insulation degradation problem that is prone to occur in high-altitude, low-pressure environments. It monitors the partial discharge initiation voltage and the rate of change of the winding insulation surface temperature, and performs safety assessments and feedback corrections based on the principle of thermodynamic entropy increase.

[0075] Please refer to Figure 6 , Figure 6 This application illustrates a detailed flowchart of S500 in an exemplary high-altitude eVTOL motor composite heat dissipation control method. S500 includes: S510: In this embodiment, according to Paschen's law, the gas breakdown voltage is the product of the air pressure and the electrode spacing. At high altitudes and low air pressure, the partial discharge initiation voltage of the air is significantly reduced, making the motor winding insulation more susceptible to electrical erosion.

[0076] In one possible implementation of this embodiment, the step of monitoring the partial discharge initiation voltage includes: S511: An ultra-high frequency antenna or high-frequency current transformer is installed near the high-voltage junction box or winding end of each motor to capture weak electromagnetic pulse signals generated by partial discharge. These sensors have high sensitivity and wide bandwidth characteristics, capable of detecting weak discharges at the picocoulomb level.

[0077] S512: By analyzing the amplitude, phase distribution, and pulse repetition rate of the sensor signal, and combining this with the current air pressure and motor voltage, the partial discharge initiation voltage under the current operating condition is estimated online. The estimated value is compared with the current peak value of the motor phase voltage to obtain the insulation safety margin. When the safety margin is lower than the preset value, a warning signal is issued.

[0078] S520: In this embodiment, simply monitoring temperature is insufficient to assess the aging rate of insulation. According to the principle of thermodynamic entropy increase, material aging is a process in which the disorder of its internal microstructure increases, and this process is closely related to temperature and the rate of temperature change.

[0079] In one possible implementation of this embodiment, the step of calculating the security entropy increase threshold includes: S521: Utilizing a distributed fiber Bragg grating temperature sensor array embedded at the end of the stator winding, this sensor measures the rate of temperature change on the surface of the insulation layer with high spatial resolution and a high sampling rate. This indicates that fiber Bragg grating sensors have the advantages of being resistant to electromagnetic interference, small in size, and easy to embed.

[0080] S522: Based on the material aging kinetics model and the heat resistance grade of the insulation material, define a temperature rise offset compensation matrix. The safety entropy increase threshold of the coupled system is used The calculation formula is as follows: In the formula, The activation energy of insulating materials; Boltzmann's constant; For reference temperature; The maximum operating temperature allowed by the insulation class; The safety factor function is a function whose value ranges from [0,1], and is derived from the temperature rise offset compensation matrix. The maximum predicted temperature rise is dynamically adjusted. When the predicted additional temperature rise is large, The threshold for safe entropy increase was lowered. More stringent, meaning the upper limit for the allowable rate of temperature change is reduced.

[0081] S530: In this embodiment, the measured temperature change rate will be... With the security entropy increase threshold derived from S520 By making comparisons, a protection logic is formed.

[0082] In one possible implementation of this embodiment, the judgment and correction steps include: S531: Calculate the absolute value of the temperature change rate at each temperature measurement point in real time and compare it with the safety entropy increase threshold for that point. A comparison is made. If the absolute value of the temperature change rate is greater than the safe entropy increase threshold, it is determined that the rate of increase of the thermodynamic entropy of the insulation material at that location is too fast, posing a risk of accelerated aging.

[0083] S532: When an over-threshold event occurs, execute the reverse correction logic. The equivalent thermal conductivity of the air gap calculated in S320 is then used. Multiply by a correction factor less than 1 The heat dissipation model is artificially made to believe that the environment's thermal conductivity is worse than it actually is, thereby triggering a stronger cooling response.

[0084] S533: The corrected equivalent thermal conductivity of the air gap is fed back to step S300, triggering the re-execution of the equivalent thermal resistance conversion procedure that started in S320. Because the equivalent thermal conductivity of the air gap is artificially reduced, the recalculated dynamic thermal path topology vector... This will indicate a more severe heat dissipation situation, thereby generating a larger cooling flow command or a stronger phase change cooling command through S400, forcibly reducing the winding temperature and its rate of change, suppressing the rate of increase of the thermodynamic entropy of the insulation material within a safe threshold, and achieving the purpose of actively extending the insulation life.

[0085] In summary, this method, based on rarefied gas dynamics, heat transfer, and nonlinear system identification theory, achieves precise feedforward-feedback composite control of the eVTOL multi-motor cooling system in high-altitude environments. It decouples environmental and internal heat source characteristics through three-stage progressive filtering, constructs a precise thermal offset compensation matrix through degradation mapping, spatial interference, and heat flow superposition, obtains the dynamic thermal path topology vector through progressive equivalent thermal resistance conversion, and finally maps it to feedforward control commands for micro-flow cooling and phase change energy storage. Simultaneously, it uses the thermodynamic entropy increase threshold as the trigger condition for safety closed-loop correction. This method significantly improves the control accuracy, response speed, and proactive insulation life protection of the propulsion motor in high-altitude eVTOLs, demonstrating outstanding value for aerospace engineering applications.

[0086] Example 2: This invention was deployed and validated during high-altitude flight tests of a six-rotor manned eVTOL technology demonstrator. The demonstrator has a maximum takeoff weight of 2500 kg and is equipped with six independent propulsion motor units, each with a peak power of 180 kW and a rated power of 120 kW. The cooling system employs a liquid-cooled circulation integrated into the arm structure, with each liquid cooler equipped with a micro-flow regulating valve. Paraffin / graphite composite phase-change energy storage modules are integrated into the stator windings of each motor. The test site was located at a plateau airport at an altitude of 4200 m, with an ambient air pressure approximately 60% of that at sea level and an atmospheric density approximately 64% of that at sea level.

[0087] I. Implementation and Configuration; Each motor nacelle is equipped with 8 miniature dynamic barometric pressure sensors (circumferentially spaced at 45° intervals), 2 constant-temperature hot-wire anemometers, 2 thermopile-type radiative heat flux sensors, 1 ultra-high frequency partial discharge sensor, and 6 fiber Bragg grating temperature sensors. The sampling frequency is 1000Hz. The flight control computer has two built-in FPGAs, with an algorithm execution cycle of 10ms. The liquid cooling flow rate is adjustable from 0.5L / min to 8L / min, and the phase change trigger voltage range is -100mA to +100mA. Algorithm parameters: The range is 0.001Hz to 0.05Hz. , mm, eV, eV / K, K, K.

[0088] II. Experimental Procedure; After completing baseline calibration at a plain airport at an altitude of 500m, the demonstrator aircraft was transferred to a plateau airport at 4200m for testing under four operating conditions. Condition 1: Ground hovering, 80% maximum continuous power (96kW) for 10 minutes. Condition 2: Vertical climb, climbing at 5m / s to an altitude of 500m, with single-unit power instantaneously increasing from 96kW to 150kW. Condition 3: Low-speed forward flight, flying at 60 indicated airspeed along a 2000m rectangular route. Condition 4: Briefly limiting the cooling flow to motor #6 in Condition 3 to verify the S500 protection mechanism. The control group used traditional PID constant temperature control without enabling the phase change active triggering function.

[0089] III. Experimental Results and Analysis; 1. Comparison of hovering thermal management performance under operating condition 1; The highest winding temperature at the end of the 10-minute hovering period is shown in Table 1.

[0090] Table 1 shows a comparison of the highest temperatures (°C) of the 4200m hovering winding. The method of this invention accurately identifies motors No. 2 and No. 4 as being in the low-pressure wake region through spatial interference correction and increases the cooling flow in advance, resulting in a 9.8°C reduction in the average maximum temperature and a 79% reduction in the standard deviation.

[0091] 2. Transient response during vertical climb in operating condition 2; In the control group, the temperature of motor winding No. 4 rose by 21.5℃ to 175.3℃ within 10 seconds. Under the control of the method of this invention, the temperature peak was only 12.8℃ (maximum 152.9℃). The phase change trigger command was activated within 10ms after the ramp command, outputting an 80mA current, absorbing approximately 85kJ of latent heat of fusion within 5 seconds, and the peak value suppression reached 40.5%.

[0092] 3. Heat dissipation distribution in low-speed forward flight mode 3; Table 2 shows the average values ​​of key parameters for each motor before the 4200m flight. Motors No. 2, No. 4, and No. 6 , When the flow rate drops below 0.4, the system will reduce the flow duty cycle. Increased to above 0.85, effectively compensating for deteriorated heat dissipation.

[0093] 4. Verification of insulation protection mechanism under operating condition 4; Limit the flow of motor No. 6 The temperature change rate decreased from 0.85 to 0.60 over 30 seconds. Increased to 1.15K / s. Safe entropy increase threshold. for: ; because The system triggers a reverse correction within 15ms. Multiply by 0.95, It recovers to 0.87 within 0.5 seconds, and within 10 seconds. It dropped to 0.61 K / s.

[0094] Table 3 Parameters before and after protection mechanism triggering 5. Energy consumption statistics; Throughout the entire flight test envelope, the energy consumption of the auxiliary heat dissipation method of this invention accounted for 2.81% of the total battery output, compared to 3.92% in the control group, resulting in energy savings of approximately 28.3%.

[0095] IV. Conclusion; This embodiment verifies the effectiveness of the method of the present invention in a real high-altitude flight environment: (1) the hot spot temperature of the motor is reduced by 9.8℃, and the standard deviation of the multi-motor temperature is reduced by 79%; (2) the transient temperature peak suppression reaches 40.5%; (3) the safety entropy increase protection mechanism responds within 15ms, effectively suppressing the accelerated aging of insulation; (4) the auxiliary heat dissipation system saves 28.3% energy. The present invention provides a high-precision, high-efficiency, and high-reliability solution for the thermal management of eVTOL motors at high altitudes.

[0096] Example 3: A high-altitude eVTOL motor composite heat dissipation control system, with an interface as shown in the figure. Figure 7 , Figure 8 , Figure 9 , Figure 10 , Figure 11 and Figure 12 As shown, it contains six interfaces, including: Thermal load spectrum interface: Through three-level progressive filtering, the rarefied environment and aerodynamic interference are decoupled to generate independent initial thermal load spectra for each motor.

[0097] Temperature rise compensation interface: Based on heat load degradation mapping and spatial interference correction, a multidimensional temperature rise offset compensation matrix is ​​output.

[0098] Thermal topology interface: Execute the equivalent thermal resistance conversion program to obtain the dynamic thermal topology vector that reflects the differences in thermal inertia of each motor.

[0099] Feedforward command interface: The thermal path topology vector is mapped to feedforward control commands for cooling flow and phase change energy storage to achieve advanced heat dissipation response.

[0100] Entropy increase safety interface: Monitors partial discharge and insulation temperature change rate, and triggers reverse correction based on entropy increase threshold to actively extend insulation life.

[0101] State Mapping Interface: Displays the thermal equilibrium state space lookup table mapping relationship, supporting real-time retrieval and reconstruction of the optimal feedforward gain.

[0102] The system includes: The multi-physics signal acquisition and decoupling module is used to acquire raw signals in real time under high-altitude flight conditions, decouple the raw signals by a three-level progressive filtering layer, and superimpose the three-level filtering results to generate independent initial thermal load spectra of each motor. The temperature rise offset compensation matrix generation module is used to perform three-level logic calculations based on the initial heat load spectrum, including heat load degradation mapping, spatial interference correction, and heat flux density superposition, and output the temperature rise offset compensation matrix specific to each motor. The dynamic thermal path topology vector acquisition module is used to start the equivalent thermal resistance conversion program for the temperature rise offset compensation matrix. The equivalent thermal resistance conversion program is executed in the progressive order of stator yoke circumferential thermal diffusion identification, air gap equivalent thermal conductivity dynamic reconstruction, and casing and environment thermal capacity coupling mapping. The dynamic thermal path topology vector reflecting the current thermal time constant difference of each motor is obtained through the equivalent thermal resistance conversion program. The feedforward control command generation and execution module is used to convert the dynamic thermal path topology vector into the duty cycle feedforward control command of the cooling medium micro-flow regulating valve and the phase interface shift trigger control command of the phase change energy storage unit according to the thermal equilibrium state space mapping relationship, and drive the heat dissipation actuator to act according to the control command. The insulation condition monitoring and feedback correction module is used to monitor the partial discharge initiation voltage and the temperature change rate of the winding insulation layer surface in a high-altitude, thin air environment. If the change rate exceeds the safety entropy increase threshold derived from the temperature rise offset compensation matrix, the equivalent thermal conductivity of the air gap is corrected in reverse, and the process is re-executed to suppress the rate of increase of the thermodynamic entropy of the insulation material.

[0103] Those skilled in the art will understand that the embodiments of this application are provided as methods, systems, or computer program products. Therefore, this application takes the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application takes the form of a computer program product implemented on one or more computer storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer program code. The solutions in the embodiments of this application are implemented using various computer languages, exemplified by the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0104] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, as well as combinations of blocks in the flowchart illustrations and / or block diagrams, are implemented by computer program instructions. These computer program instructions are provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart illustrations and / or block diagrams.

[0105] These computer program instructions are also stored in a computer read-memory that can direct a computer or other programmed data processing device to operate in a particular manner, such that the instructions stored in the computer read-memory produce an article of manufacture including instruction means that implement the functions specified in the flowchart or multiple flowcharts and / or block diagram blocks or multiple block diagrams.

[0106] These computer program instructions are also loaded onto a computer or other programming data processing device to cause a series of operational steps to be performed on the computer or other programming device to produce a computer-implemented process, such that the instructions, which execute on the computer or other programming device, provide steps for implementing the functions specified in the flowchart flow or multiple flows and / or the block diagram blocks or multiple blocks.

[0107] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0108] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A composite heat dissipation control method for a high-altitude eVTOL motor, characterized in that, include: The raw signals under high-altitude flight conditions are acquired in real time, and the raw signals are decoupled by a three-level progressive filtering layer. The results of the three-level filtering are superimposed to generate independent initial thermal load spectra of each motor. Based on the initial heat load spectrum, three-layer logic calculations are performed sequentially: heat load degradation mapping, spatial interference correction, and heat flux density superposition, outputting a temperature rise offset compensation matrix specific to each motor. The equivalent thermal resistance conversion program is started for the temperature rise offset compensation matrix. The equivalent thermal resistance conversion program is executed in the progressive order of stator yoke circumferential thermal diffusion identification, air gap equivalent thermal conductivity dynamic reconstruction, and casing and environment thermal capacity coupling mapping. The equivalent thermal resistance conversion program obtains the dynamic thermal path topology vector that reflects the current thermal time constant difference of each motor. The dynamic thermal path topology vector is converted into a duty cycle feedforward control command for the cooling medium micro-flow regulating valve and a phase interface shift trigger control command for the phase change energy storage unit according to the thermal equilibrium state space mapping relationship. The heat dissipation actuator is driven to act according to the control command. The partial discharge initiation voltage and the rate of change of the surface temperature of the winding insulation layer are monitored in the high-altitude, thin air environment. If the rate of change exceeds the safety entropy increase threshold derived from the temperature rise offset compensation matrix, the equivalent thermal conductivity of the air gap is corrected in reverse, and the process is repeated to suppress the rate of increase of the thermodynamic entropy of the insulation material.

2. The high-altitude eVTOL motor composite heat dissipation control method according to claim 1, characterized in that, The decoupling process of the three-stage progressive filter layer includes: The first-stage filtering layer uses an adaptive high-pass filter built based on the international standard atmospheric model to remove the convective reference drift caused by the sudden drop in atmospheric density due to altitude changes. The second-level filtering layer constructs a narrowband bandpass filter bank based on the blade passage frequency and second harmonic frequency of adjacent rotors. Combined with wavelet packet transform time-frequency decomposition, it separates the asymmetric aerodynamic interference components generated by the wake interference of adjacent rotors and defines the vorticity amplitude characteristic to characterize the intensity of wake interference. The third-level filtering layer processes the total electromagnetic loss power obtained from the equivalent circuit model of the motor through Kalman filtering, and extracts the transient characteristics of the internal electromagnetic loss of the motor under the current differential thrust distribution strategy.

3. The high-altitude eVTOL motor composite heat dissipation control method according to claim 2, characterized in that, The generation of the initial spectral lines for the heat load includes: The signal after the first stage of filtering, representing the convection reference correction, the asymmetric aerodynamic interference component of the second stage of filtering output, and the electromagnetic loss transient characteristics of the third stage of filtering output are respectively mapped to the comparable interval through a normalization function; Based on the current flight phase and the motor operating point, fusion weights that meet the normalization conditions are dynamically allocated, and a weighted superposition is used to generate a fusion weight for the first... The initial spectral line of the heat load of the trolley motor as a function of time is expressed as: In the formula, Indicates the first TE Connectivity at all times Initial spectral value of heat load; , , These are the signals output from the first, second, and third stages of filtering, respectively. , , For standardized functions; , , It is to satisfy The dynamic weighting coefficients.

4. The high-altitude eVTOL motor composite heat dissipation control method according to claim 3, characterized in that, The temperature rise offset compensation matrix is ​​formed by: The heat load degradation mapping layer defines a degradation coefficient that characterizes the degree of decline in convective heat transfer capacity. The calculation formula is: In the formula, It is a function of the current effective Nusselt number based on the heat load spectral line; The rated Nusselt number under sea-level reference conditions, and the attenuation coefficient. The value range is between [0,1], and the average value of the overall motor attenuation coefficient and the variance reflecting the surface non-uniformity are statistically analyzed; The spatial interference correction layer introduces an asymmetric wake interference angle constructed from the second-stage filter vorticity amplitude and the phase difference between rotors. Based on the correction function containing vorticity amplitude, asymmetric wake interference angle and calibration coefficient, the average attenuation coefficient is spatially compensated to obtain the spatially corrected heat dissipation capacity attenuation coefficient. The heat flux density superposition layer uses the spatially corrected heat dissipation capacity attenuation coefficient as a spatial modulation function, and performs nonlinear convolution operation with the winding heat flux density distribution allocated according to the prior spatial weight of the finite element model to generate a temperature rise offset compensation matrix.

5. The high-altitude eVTOL motor composite heat dissipation control method according to claim 1, characterized in that, The stator yoke circumferential thermal diffusion identification step is as follows: The submatrix corresponding to the geometric region of the stator yoke is extracted from the temperature rise offset compensation matrix, and the temperature gradient distribution of the submatrix along the circumferential direction is calculated by the discrete gradient operator based on the central difference method. A circumferential thermal diffusivity factor is defined, which is inversely proportional to the root mean square of the circumferential gradient magnitude. It is calculated by taking the root mean square of the gradient magnitude over the entire circumference and is used to quantify the non-uniformity of heat accumulation in the yoke caused by external asymmetric heat dissipation.

6. The high-altitude eVTOL motor composite heat dissipation control method according to claim 5, characterized in that, The dynamic reconstruction step of the equivalent thermal conductivity of the air gap includes: The Knudsen number, which characterizes the rarefaction of a gas, is determined by the ratio of the mean free path of air molecules to the characteristic length of the air gap. In response to the decrease in air pressure at high altitudes leading to an increase in the Knudsen number and entry into the transition flow region, a modified interpolation formula is used to dynamically reconstruct the equivalent thermal conductivity of the air gap, expressed as: In the formula, The equivalent thermal conductivity of the air gap is... The standard thermal conductivity of air at the current temperature; It is a Prandtl number; This is a comprehensive coefficient. Knudsen number, defined as the mean free path of air molecules With air gap characteristic length The ratio of .

7. The high-altitude eVTOL motor composite heat dissipation control method according to claim 6, characterized in that, The thermal capacity coupling mapping steps between the casing and the environment are as follows: Calculate the effective heat capacity of the external air, which is determined by the product of air density, specific heat capacity at constant pressure, and effective heat transfer volume. The effective heat capacity of the external air is equal to the product of air density, specific heat capacity at constant pressure, and effective heat transfer volume. Based on the connection between the equivalent heat capacity of the motor housing and the effective heat capacity of the external air through a thermal resistance network, the dominant thermal time constant of the i-th motor is calculated, and the expression is: In the formula, The thermal time constant, This is the equivalent heat capacity of the motor housing; The effective heat capacity of the outside air; The total equivalent thermal resistance from the winding to the environment; The dynamic thermal path topology vector is generated by combining the circumferential thermal diffusivity, the air gap equivalent thermal conductivity, the total equivalent thermal resistance, and the dominant thermal time constant.

8. The high-altitude eVTOL motor composite heat dissipation control method according to claim 1, characterized in that, The process of converting the dynamic thermal path topology vector into a duty cycle feedforward control command for a micro-flow regulating valve of the cooling medium according to the thermal equilibrium state space mapping relationship includes: Using the thermal time constant and total equivalent thermal resistance in the dynamic thermal path topology vector as indexes, the optimal control multidimensional lookup table constructed offline with the goal of minimizing the total energy consumption of the auxiliary heat dissipation system is queried to obtain the duty cycle feedforward value of the micro-flow regulating valve. In response to the predicted decrease in thermal time constant, the duty cycle of the micro-flow regulating valve in the cooling circuit is increased in advance to increase the flow rate of coolant to the corresponding motor in order to suppress temperature spikes.

9. The high-altitude eVTOL motor composite heat dissipation control method according to claim 1, characterized in that, The process of converting the dynamic thermal path topology vector into a phase interface shift trigger control command for the phase change energy storage unit according to the thermal equilibrium state spatial mapping relationship includes: When a positive heat flux peak is predicted based on the dynamic thermal path topology vector, a positive current signal is output to drive the micro thermoelectric cooler close to the encapsulation wall of the phase change material to work in heating mode, causing the solid-liquid interface to move towards the solid region to absorb the latent heat of fusion. When the predicted heat load decreases, the output reverse current signal causes the liquid-solid interface to move towards the liquid region to release latent heat, and the phase interface moving rate is approximately proportional to the applied current density.

10. The high-altitude eVTOL motor composite heat dissipation control method according to claim 1, characterized in that, The monitoring of partial discharge initiation voltage in high-altitude, thin-air environments includes: The weak electromagnetic pulse signal generated by partial discharge is captured by an ultra-high frequency antenna or high frequency current transformer installed in the high-voltage junction box or winding end of the motor. Based on the amplitude, phase distribution, and pulse repetition rate of the captured signal, combined with the current air pressure and motor voltage, the partial discharge initiation voltage is estimated online, and the insulation safety margin is obtained by comparing it with the current peak value of the motor phase voltage.

11. The high-altitude eVTOL motor composite heat dissipation control method according to claim 1, characterized in that, If the rate of change exceeds the safety entropy increase threshold derived from the temperature rise offset compensation matrix, the equivalent thermal conductivity of the air gap is corrected in reverse, including: The rate of temperature change on the surface of the winding insulation layer was measured using a distributed fiber optic grating temperature sensor array. The safe entropy increase threshold is calculated based on a material aging kinetic model, using the following formula: In the formula, For the safety entropy increase threshold, The activation energy of insulating materials; Boltzmann's constant; For reference temperature; The maximum operating temperature allowed by the insulation class; The safety factor function has values ​​in the range [0,1], derived from the temperature rise offset compensation matrix. The maximum temperature rise prediction value is dynamically adjusted. When the absolute value of the measured temperature change rate exceeds the safe entropy increase threshold, the equivalent thermal conductivity of the air gap is multiplied by a correction factor of less than 1 and fed back to the equivalent thermal resistance conversion program for re-execution, so as to forcibly enhance the cooling response and suppress the rate of increase of the thermodynamic entropy of the insulating material within the safe threshold.

12. The high-altitude eVTOL motor composite heat dissipation control system according to any one of claims 1-11, characterized in that the system include: The multi-physics signal acquisition and decoupling module is used to acquire raw signals in real time under high-altitude flight conditions, decouple the raw signals by a three-level progressive filtering layer, and superimpose the three-level filtering results to generate independent initial thermal load spectra of each motor. The temperature rise offset compensation matrix generation module is used to perform three-level logic calculations based on the initial heat load spectrum, including heat load degradation mapping, spatial interference correction, and heat flux density superposition, and output the temperature rise offset compensation matrix specific to each motor. The dynamic thermal path topology vector acquisition module is used to start the equivalent thermal resistance conversion program for the temperature rise offset compensation matrix. The equivalent thermal resistance conversion program is executed in the progressive order of stator yoke circumferential thermal diffusion identification, air gap equivalent thermal conductivity dynamic reconstruction, and casing and environment thermal capacity coupling mapping. The dynamic thermal path topology vector reflecting the current thermal time constant difference of each motor is obtained through the equivalent thermal resistance conversion program. The feedforward control command generation and execution module is used to convert the dynamic thermal path topology vector into the duty cycle feedforward control command of the cooling medium micro-flow regulating valve and the phase interface shift trigger control command of the phase change energy storage unit according to the thermal equilibrium state space mapping relationship, and drive the heat dissipation actuator to act according to the control command. The insulation condition monitoring and feedback correction module is used to monitor the partial discharge initiation voltage and the temperature change rate of the winding insulation layer surface in a high-altitude, thin air environment. If the change rate exceeds the safety entropy increase threshold derived from the temperature rise offset compensation matrix, the equivalent thermal conductivity of the air gap is corrected in reverse, and the process is re-executed to suppress the rate of increase of the thermodynamic entropy of the insulation material.

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