Methods, devices, and storage media for simulating vehicle motor temperature

Abstract

This application discloses a method, apparatus, and storage medium for simulating vehicle motor temperature, belonging to the field of vehicle motor development technology. The method includes: acquiring a physical model and boundary conditions of the motor, wherein the physical model is a volume mesh model; determining a mathematical model based on the physical model of the motor; applying the boundary conditions and the mathematical model to the physical model of the motor to solve for the motor cooling flow field and the motor temperature field; wherein the solid wall temperature and near-wall fluid temperature in the heat transfer conservation equation between the fluid and solid in the mathematical model are real-time measured values. This method can simultaneously obtain the motor cooling flow field and the motor temperature field, simplifying the calculation process, shortening the acquisition time of the motor cooling flow field and the motor temperature field, and more accurately reflecting the motor temperature situation.

Description

Technical Field

[0001] This application relates to the field of vehicle motor development technology, and in particular to a method, apparatus and storage medium for simulating vehicle motor temperature. Background Technology

[0002] As the core power component of vehicles, electric motors are developing towards higher power density, miniaturization, and integration, but they also face problems such as a sharp increase in heat generation and insufficient effective heat dissipation space. To explore the changes in motor temperature, simulation studies on motor temperature have emerged.

[0003] In related technologies, motor temperature simulation typically involves constructing a motor model, simulating a separate flow field, and then substituting the heat transfer boundary as input into a finite element model to calculate the finite element temperature field. However, existing technologies require iterative calculations between two different models to obtain accurate flow and temperature field results, making the calculation process cumbersome and time-consuming. Summary of the Invention

[0004] In view of this, this application provides a method, apparatus and storage medium for simulating vehicle motor temperature, which simplifies the calculation process, shortens the acquisition time of motor cooling flow field and motor temperature field, and can more accurately reflect the temperature of the motor.

[0005] Specifically, the following technical solutions are included:

[0006] In a first aspect, embodiments of this application provide a method for simulating the temperature of a vehicle motor, the method comprising:

[0007] Obtain the physical model and boundary conditions of the motor, wherein the physical model is a volume mesh model;

[0008] Based on the physical model of the motor, a mathematical model is determined;

[0009] The boundary conditions and the mathematical model are applied to the physical model of the motor to solve for the motor cooling flow field and the motor temperature field.

[0010] In the mathematical model, the solid wall temperature and the near-wall fluid temperature in the heat transfer conservation equation between the fluid and the solid are both measured in real time.

[0011] In some embodiments, the mathematical model includes the volume fraction conservation equation, the continuity equation, the momentum equation, the energy conservation equation, the energy transfer control equation within the solid, and the heat transfer conservation equation between the fluid and the solid.

[0012] The formula for calculating the volume fraction conservation equation is as follows:

[0013]

[0014] In the formula: n represents the number of fluid phases; α i This represents the volume fraction;

[0015] The formula for calculating the continuity equation is as follows:

[0016]

[0017] In the formula: ρ i This represents density, v i It represents speed, m ij This represents the mass transfer rate from fluid phase i to fluid phase j, m ji This represents the mass transfer rate from fluid phase j to fluid phase i. This represents the fluid mass source term, where V represents volume, t represents time, and A represents area.

[0018] The formula for calculating the momentum equation is as follows:

[0019]

[0020] In the formula: p represents pressure, g represents the gravitational vector, and F i F i t These represent molecular stress and turbulent stress, respectively. i This represents the interphase momentum transfer per unit volume, (F int ) i It represents cohesion. This represents the fluid momentum source term, v i v j This represents the velocity corresponding to fluid phases i and j;

[0021] The formula for calculating the energy conservation equation is as follows:

[0022]

[0023] In the formula: E i H represents the total energy. i This represents the total enthalpy, k. eff T represents the thermal conductivity. i D represents temperature. i This represents the viscous stress tensor, b i This represents the volume force vector, Q. ij This represents the interphase heat transfer rate. S represents the heat transfer rate from the interface between different fluid phases to fluid phase i. u This represents the fluid heat source term, h.i (T ij This indicates the interface temperature T. ij Enthalpy of the lower fluid phase i;

[0024] The calculation formula for the energy transfer control equation within the solid is as follows:

[0025]

[0026] In the formula: ρ represents the density of the solid, C p This represents specific heat, and T represents temperature. This represents the heat flux vector, v s S represents the solid convection velocity. u This represents the solid heat source term;

[0027] The heat transfer conservation equation between the fluid and the solid is as follows:

[0028]

[0029] In the formula: λ represents the thermal conductivity of the solid, T represents the temperature of the solid, n represents the thickness of the solid, and h represents the convective heat transfer coefficient. w T represents the surface temperature of the solid. f This indicates the fluid temperature near the wall.

[0030] In some embodiments, before obtaining the physical model of the motor, the method further includes:

[0031] Obtain the assembly model of the motor;

[0032] The assembly model of the motor is grouped and meshed to obtain a mesh model;

[0033] The physical model of the motor is obtained by dividing the computational domain and volume mesh of the surface mesh model. The computational domain includes a solid domain, a fluid domain and a rotating fluid domain. The rotating fluid domain has a rotation center, a rotation direction and a rotation speed.

[0034] In some embodiments, determining the mathematical model based on the physical model of the motor includes:

[0035] Based on the physical model of the motor, a mathematical model is determined that corresponds one-to-one with the computational domain in the physical model of the motor.

[0036] In some embodiments, the boundary conditions include motor performance data, motor loss data, material properties of each component of the motor, and cooling flow rate of the motor.

[0037] In some embodiments, the boundary conditions include equivalent thermal resistance data, which is obtained by converting insulation data.

[0038] The insulation data includes insulation class, pure copper slot fill factor, silicon steel sheet stacking coefficient, paint thickness, insulating paper thickness, and welding coating thickness and width.

[0039] In some embodiments, the equivalent thermal resistance data includes stator / rotor core data, stator slot data, and end winding data.

[0040] The stator / rotor core data includes the core's axial equivalent thermal conductivity, and the formula for calculating the core's axial equivalent thermal conductivity is as follows:

[0041]

[0042] In the formula: λ T K represents the axial equivalent thermal conductivity of the core. Fe This represents the core stacking factor, δ. Fe δ0 represents the thickness of the core laminations, λ1 represents the thermal conductivity of the silicon steel sheet in the core, and λ0 represents the thermal conductivity of the insulating medium between the core laminations.

[0043] The stator slot data includes the thermal conductivity of the equivalent insulation layer, and the formula for calculating the thermal conductivity of the equivalent insulation layer is as follows:

[0044]

[0045] In the formula: λ q λ represents the thermal conductivity of the equivalent insulating layer. i This represents the thermal conductivity, δ. i This represents the thickness, and n represents the number of insulation categories;

[0046] The end winding data includes structural thermal resistance, which comprises a first structural thermal resistance and a second structural thermal resistance. The first structural thermal resistance is the material thermal resistance of the enamel coating, and the second structural thermal resistance is the material thermal resistance of the enamel coating and the coating layer.

[0047] The formula for calculating the thermal resistance of the first structure is:

[0048]

[0049] In the formula: R1 represents the thermal resistance of the first structure, δ1 represents the material thickness of the paint, and λ1 represents the thermal conductivity of the paint material.

[0050] The formula for calculating the thermal resistance of the second structure is:

[0051]

[0052] In the formula: R2 represents the thermal resistance of the second structure, ΔR represents the thermal resistance of the coating material, δ2 represents the material thickness of the coating, and λ2 represents the thermal conductivity of the coating material.

[0053] Secondly, embodiments of this application provide a device for simulating the temperature of a vehicle motor, the device comprising:

[0054] The acquisition module is used to acquire the physical model and boundary conditions of the motor, wherein the physical model is a volume mesh model;

[0055] A mathematical model determination module is used to determine a mathematical model based on the physical model of the motor;

[0056] The solution module is used to apply the boundary conditions and the mathematical model to the physical model of the motor to solve for the motor cooling flow field and the motor temperature field.

[0057] In the mathematical model, the solid wall temperature and the near-wall fluid temperature in the heat transfer conservation equation between the fluid and the solid are both measured in real time.

[0058] In some embodiments, the mathematical model includes the volume fraction conservation equation, the continuity equation, the momentum equation, the energy conservation equation, the energy transfer control equation within the solid, and the heat transfer conservation equation between the fluid and the solid.

[0059] The formula for calculating the volume fraction conservation equation is as follows:

[0060]

[0061] In the formula: n represents the number of fluid phases; α i This represents the volume fraction;

[0062] The formula for calculating the continuity equation is as follows:

[0063]

[0064] In the formula: ρ i This represents density, v i It represents speed, m ij This represents the mass transfer rate from fluid phase i to fluid phase j, m ji This represents the mass transfer rate from fluid phase j to fluid phase i. This represents the fluid mass source term, where V represents volume, t represents time, and A represents area.

[0065] The formula for calculating the momentum equation is as follows:

[0066]

[0067] In the formula: p represents pressure, g represents the gravitational vector, and F i F i t These represent molecular stress and turbulent stress, respectively. i This represents the interphase momentum transfer per unit volume, (F int ) i It represents cohesion. This represents the fluid momentum source term, v i v j This represents the velocity corresponding to fluid phases i and j;

[0068] The formula for calculating the energy conservation equation is as follows:

[0069]

[0070] In the formula: E i H represents the total energy. i This represents the total enthalpy, k. eff T represents the thermal conductivity. i D represents temperature. i This represents the viscous stress tensor, b i This represents the volume force vector, Q. ij This represents the interphase heat transfer rate. S represents the heat transfer rate from the interface between different fluid phases to fluid phase i. u This represents the fluid heat source term, h. i (T ij This indicates the interface temperature T. ij Enthalpy of the lower fluid phase i;

[0071] The calculation formula for the energy transfer control equation within the solid is as follows:

[0072]

[0073] In the formula: ρ represents the density of the solid, C p This represents specific heat, and T represents temperature. This represents the heat flux vector, v s S represents the solid convection velocity. u This represents the solid heat source term;

[0074] The heat transfer conservation equation between the fluid and the solid is as follows:

[0075]

[0076] In the formula: λ represents the thermal conductivity of the solid, T represents the temperature of the solid, n represents the thickness of the solid, and h represents the convective heat transfer coefficient. w T represents the surface temperature of the solid. f This indicates the fluid temperature near the wall.

[0077] Thirdly, embodiments of this application provide a storage medium that, when instructions in the storage medium are executed by a processor of an electronic device, enables the electronic device to perform the vehicle motor temperature simulation method described in the first aspect above.

[0078] The vehicle motor temperature simulation method provided in this application obtains the physical model and boundary conditions of the motor, determines a mathematical model based on the physical model, and then applies the boundary conditions and mathematical model to the physical model of the motor. Simultaneously, it solves for the motor cooling flow field and motor temperature field, simplifying the calculation process and shortening the time required to obtain these fields. Furthermore, since the solid wall temperature and near-wall fluid temperature within the heat transfer conservation equation between the fluid and solid in the mathematical model are measured in real time, the interaction between the solid temperature and the fluid boundary can be considered in real time during the model's solution process. This allows the obtained motor cooling flow field and motor temperature field to more accurately reflect the motor's temperature condition. Attached Figure Description

[0079] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0080] Figure 1 A flowchart illustrating a method for simulating vehicle motor temperature as provided in this application embodiment;

[0081] Figure 2 A flowchart illustrating another method for simulating vehicle motor temperature provided in this application embodiment;

[0082] Figure 3(a) is a schematic diagram of the motor temperature field provided in an embodiment of this application;

[0083] Figure 3(b) is a schematic diagram of the motor temperature field provided in an embodiment of this application;

[0084] Figure 4 This is a schematic diagram of the motor cooling flow field provided in an embodiment of this application;

[0085] Figure 5 This application provides a structural block diagram of a vehicle motor temperature simulation device. Detailed Implementation

[0086] 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, 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.

[0087] Currently, under the dual pressure of energy security and environmental issues, my country is vigorously promoting the transformation of its automotive industry, with various OEMs launching new energy vehicle models. As the core component of new energy vehicle power, the electric motor is further developing towards higher power density, miniaturization, and integration. This has also brought about problems such as a sharp increase in internal heat generation and insufficient effective heat dissipation space. Therefore, motor cooling has become a key aspect of motor technology development, necessitating precise and efficient motor cooling design analysis.

[0088] Common methods for analyzing motor cooling include the thermal network method and the weakly coupled finite element method. The thermal network method establishes a one-dimensional equivalent thermal network of the motor to analyze the thermal resistance distribution of the motor system and perform one-dimensional temperature rise analysis. However, it cannot accurately characterize the three-dimensional temperature field distribution of the motor components. The weakly coupled finite element method constructs a motor model, simulates a separate flow field, and then substitutes the heat transfer boundary as input into the finite element model to calculate the finite element temperature field. However, this method requires iterative calculations using two different models to obtain accurate flow and temperature field results, making the calculation process cumbersome and time-consuming.

[0089] To address the problem that related technologies involve cumbersome and time-consuming calculations when simulating motor temperature, this application provides a method for simulating vehicle motor temperature that can simultaneously obtain the motor cooling flow field and the motor temperature field. The calculation process is simple, quick, and can more accurately reflect the motor's temperature condition.

[0090] Figure 1 A flowchart illustrating a method for simulating vehicle motor temperature according to an embodiment of this application. See also... Figure 1 The method includes:

[0091] 101. Obtain the physical model and boundary conditions of the motor, where the physical model is a volume mesh model.

[0092] 102. Based on the physical model of the motor, determine the mathematical model.

[0093] 103. By applying the boundary conditions and mathematical model to the physical model of the motor, the cooling flow field and temperature field of the motor are obtained.

[0094] In the mathematical model, the solid wall temperature and the near-wall fluid temperature in the heat transfer conservation equation between the fluid and the solid are both measured in real time.

[0095] The vehicle motor temperature simulation method provided in this application obtains the physical model and boundary conditions of the motor, determines a mathematical model based on the physical model, and then applies the boundary conditions and mathematical model to the physical model of the motor. Simultaneously, it solves for the motor cooling flow field and motor temperature field, simplifying the calculation process and shortening the time required to obtain these fields. Furthermore, since the solid wall temperature and near-wall fluid temperature within the heat transfer conservation equation between the fluid and solid in the mathematical model are measured in real time, the interaction between the solid temperature and the fluid boundary can be considered in real time during the model's solution process. This allows the obtained motor cooling flow field and motor temperature field to more accurately reflect the motor's temperature condition.

[0096] In some embodiments, the mathematical model includes the volume fraction conservation equation, the continuity equation, the momentum equation, the energy conservation equation, the energy transfer control equation within the solid, and the heat transfer conservation equation between the fluid and the solid.

[0097] The formula for calculating the volume fraction conservation equation is as follows:

[0098]

[0099] In the formula: n represents the number of fluid phases; α i This represents the volume fraction;

[0100] The formula for calculating the continuity equation is:

[0101]

[0102] In the formula: ρ i This represents density, v i It represents speed, m ij This represents the mass transfer rate from fluid phase i to fluid phase j, m ji This represents the mass transfer rate from fluid phase j to fluid phase i. This represents the fluid mass source term, where V represents volume, t represents time, and A represents area.

[0103] The formula for calculating the momentum equation is:

[0104]

[0105] In the formula: p represents pressure, g represents the gravitational vector, and F i F i tThese represent molecular stress and turbulent stress, respectively. i This represents the interphase momentum transfer per unit volume, (F int ) i It represents cohesion. This represents the fluid momentum source term, v i v j This represents the velocity corresponding to fluid phases i and j;

[0106] The formula for calculating the energy conservation equation is:

[0107]

[0108] In the formula: E i H represents the total energy. i This represents the total enthalpy, k. eff T represents the thermal conductivity. i D represents temperature. i This represents the viscous stress tensor, b i This represents the volume force vector, Q. ij This represents the interphase heat transfer rate. S represents the heat transfer rate from the interface between different fluid phases to fluid phase i. u This represents the fluid heat source term, h. i (T ij This indicates the interface temperature T. ij Enthalpy of the lower fluid phase i;

[0109] The formula for calculating the governing equation for energy transfer in a solid is as follows:

[0110]

[0111] In the formula: ρ represents the density of the solid, C p This represents specific heat, and T represents temperature. This represents the heat flux vector, v s S represents the solid convection velocity. u This represents the solid heat source term;

[0112] The heat transfer conservation equation between fluid and solid is:

[0113]

[0114] In the formula: λ represents the thermal conductivity of the solid, T represents the temperature of the solid, n represents the thickness of the solid, and h represents the convective heat transfer coefficient. w T represents the surface temperature of the solid. f This indicates the fluid temperature near the wall.

[0115] In some embodiments, before obtaining the physical model of the motor, the method further includes:

[0116] Obtain the assembly model of the motor;

[0117] The assembly model of the motor is grouped and meshed to obtain a mesh model;

[0118] The computational domain is divided into a face mesh model and a volume mesh to obtain the physical model of the motor. The computational domain includes a solid domain, a fluid domain, and a rotating fluid domain. The rotating fluid domain has a rotation center, rotation direction, and rotation speed.

[0119] In some embodiments, a mathematical model is determined based on the physical model of the motor, including:

[0120] Based on the physical model of the motor, a mathematical model is determined that corresponds one-to-one with the computational domain in the physical model of the motor.

[0121] In some embodiments, the boundary conditions include motor performance data, motor loss data, material properties of each component of the motor, and cooling flow rate of the motor.

[0122] In some embodiments, the boundary conditions include equivalent thermal resistance data, which is obtained by converting insulation data.

[0123] The insulation data includes insulation class, pure copper slot fill factor, silicon steel sheet stacking coefficient, paint thickness, insulating paper thickness, and welding coating thickness and width.

[0124] In some embodiments, the equivalent thermal resistance data includes stator / rotor core data, stator slot data, and end winding data.

[0125] The stator / rotor core data includes the core's axial equivalent thermal conductivity, and the formula for calculating the core's axial equivalent thermal conductivity is as follows:

[0126]

[0127] In the formula: λ T K represents the axial equivalent thermal conductivity of the iron core. Fe This represents the core stacking factor, δ. Fe δ0 represents the thickness of the core laminations, λ1 represents the thermal conductivity of the silicon steel sheet in the core, and λ0 represents the thermal conductivity of the insulating medium between the core laminations.

[0128] The stator slot data includes the thermal conductivity of the equivalent insulation layer. The formula for calculating the thermal conductivity of the equivalent insulation layer is:

[0129]

[0130] In the formula: λq λ represents the thermal conductivity of the equivalent insulating layer. i This represents the thermal conductivity, δ. i This represents the thickness, and n represents the number of insulation categories;

[0131] The end winding data includes structural thermal resistance, which comprises a first structural thermal resistance and a second structural thermal resistance. The first structural thermal resistance is the material thermal resistance of the enamel coating, and the second structural thermal resistance is the material thermal resistance of both the enamel coating and the coating layer.

[0132] The formula for calculating the thermal resistance of the first structure is:

[0133]

[0134] In the formula: R1 represents the thermal resistance of the first structure, δ1 represents the material thickness of the paint, and λ1 represents the thermal conductivity of the paint material.

[0135] The formula for calculating the thermal resistance of the second structure is:

[0136]

[0137] In the formula: R2 represents the thermal resistance of the second structure, ΔR represents the thermal resistance of the coating material, δ2 represents the material thickness of the coating, and λ2 represents the thermal conductivity of the coating material.

[0138] Figure 2 A flowchart illustrating another method for simulating vehicle motor temperature provided in this application embodiment. See also... Figure 2 The method includes:

[0139] 201. Obtain the physical model of the motor.

[0140] To construct a 3D model for simulating motor temperature acquisition, a physical model of the motor must first be obtained based on its physical structure.

[0141] In this embodiment of the application, the physical model can be a three-dimensional volume mesh model.

[0142] Before this step, the physical model of the motor can be obtained through the following steps: (1) Obtain the assembly model of the motor; wherein, the assembly model of the motor may include the motor body, oil pipe, housing and end cover, etc., wherein the motor body includes stator, rotor, coil winding, magnet, rotor shaft and rotor balance disc, and the assembly model of the motor can be an assembly model based on the coordinates of the whole vehicle. (2) Group and mesh the assembly model of the motor to obtain a surface mesh model; the division of the surface mesh model prepares for the subsequent volume mesh division and simulation calculation. The grouping here refers to grouping the various components in the motor assembly model according to material properties, component type and boundary type, which is conducive to setting appropriate mesh size for each component. (3) Divide the computational domain and volume mesh of the face mesh model to obtain the physical model of the motor. The computational domain includes a solid domain, a fluid domain and a rotating fluid domain. The rotating fluid domain has a rotation center, rotation direction and speed. This step can divide the computational domain of the face mesh model according to the material properties of the components and generate the interface. Then, different volume mesh size parameters are set based on different groups. Boundary layer mesh is added to the fluid domain and no boundary layer mesh is added to the solid domain. The volume mesh is then divided to obtain the physical model of the motor.

[0143] 202, Obtain boundary conditions.

[0144] In order to set the boundary conditions, the boundary conditions required for the simulation need to be obtained before the motor temperature simulation.

[0145] In some embodiments, the boundary conditions include motor performance data, motor loss data, material properties of each component of the motor, and cooling flow rate of the motor.

[0146] In some embodiments, in addition to motor performance data, motor loss data, material properties of various components of the motor, and cooling flow rate of the motor, the boundary conditions may also include equivalent thermal resistance data, wherein the equivalent thermal resistance data is obtained by converting insulation data, and the insulation data may include insulation class, pure copper slot fill factor, silicon steel sheet stacking factor, paint thickness, insulating paper thickness, and welding coating thickness and width.

[0147] Since the current simulation model cannot reflect the insulation data of the motor, and therefore cannot reflect the heat transfer capacity between the various media in the motor, by adding an equivalent thermal resistance condition to the boundary conditions, the influence of the insulation structure on temperature can be reflected in the subsequent simulation calculations, so that the obtained temperature field can more comprehensively characterize the factors affecting the heat dissipation of the motor.

[0148] In some embodiments, the equivalent thermal resistance data includes stator / rotor core data, stator slot data, and end winding data.

[0149] The stator / rotor core data includes the core's axial equivalent thermal conductivity, and the formula for calculating the core's axial equivalent thermal conductivity is as follows:

[0150]

[0151] In the formula: λ T K represents the axial equivalent thermal conductivity of the iron core. Fe This represents the core stacking factor, δ. Fe δ represents the thickness of the core laminations, δ0 represents the thickness of the insulating medium between the core laminations, λ1 represents the thermal conductivity of the silicon steel sheet in the core, and λ0 represents the thermal conductivity of the insulating medium between the core laminations.

[0152] Since the stator / rotor core is composed of multiple layers of laminated sheets bonded together by an insulating medium, its thermal conductivity is anisotropic. Therefore, the axial equivalent thermal conductivity of the core can be calculated by combining the thermal conductivity of the silicon steel sheets and the insulating medium with the lamination coefficient.

[0153] The stator slot data includes the thermal conductivity of the equivalent insulation layer. The formula for calculating the thermal conductivity of the equivalent insulation layer is:

[0154]

[0155] In the formula: λ q λ represents the thermal conductivity of the equivalent insulating layer. i This represents the thermal conductivity, δ. i This represents the thickness, and n represents the number of insulation categories.

[0156] Since the stator slot mainly consists of four components: bare copper, enamel, insulating paper, and impregnation varnish, and each insulation structure is very thin, the insulation structure of the stator slot can be considered as an equivalent insulation layer for calculation.

[0157] The end winding data includes structural thermal resistance, which comprises a first structural thermal resistance and a second structural thermal resistance. The first structural thermal resistance is the material thermal resistance of the enamel coating, and the second structural thermal resistance is the material thermal resistance of both the enamel coating and the coating layer.

[0158] The formula for calculating the thermal resistance of the first structure is:

[0159]

[0160] In the formula: R1 represents the thermal resistance of the first structure, δ1 represents the material thickness of the paint, and λ1 represents the thermal conductivity of the paint material.

[0161] The formula for calculating the thermal resistance of the second structure is:

[0162]

[0163] In the formula: R2 represents the thermal resistance of the second structure, ΔR represents the thermal resistance of the coating material, δ2 represents the material thickness of the coating, and λ2 represents the thermal conductivity of the coating material.

[0164] Since the end winding mainly consists of bare copper and enamel, and the soldering area is also coated with a cover varnish, the equivalent thermal resistance data for the non-soldering area can be calculated by considering only one layer of enamel, while the equivalent thermal resistance data for the soldering area can be calculated by considering one layer of enamel plus one layer of cover varnish.

[0165] 203. Based on the physical model of the motor, determine the mathematical model.

[0166] When dividing the computational domain, the physical model of the motor is divided into a solid domain, a fluid domain, and a rotating fluid domain based on the material properties of the motor. Different computational domains require different mathematical models for mathematical simulation. Therefore, it is necessary to determine the mathematical model corresponding to the physical model of the motor based on the established physical model.

[0167] To ensure the accuracy of the simulation results, it is understood that the determined mathematical model is a mathematical model that corresponds one-to-one with the computational domain in the physical model of the motor.

[0168] In some embodiments, the mathematical model includes the volume fraction conservation equation, the continuity equation, the momentum equation, the energy conservation equation, the energy transfer control equation within the solid, and the heat transfer conservation equation between the fluid and the solid.

[0169] The formula for calculating the volume fraction conservation equation is as follows:

[0170]

[0171] In the formula: n represents the number of fluid phases; α i This represents the volume fraction;

[0172] The formula for calculating the continuity equation is:

[0173]

[0174] In the formula: ρ i This represents density, v i It represents speed, m ij This represents the mass transfer rate from fluid phase i to fluid phase j, m ji This represents the mass transfer rate from fluid phase j to fluid phase i. This represents the fluid mass source term, where V represents volume, t represents time, and A represents area.

[0175] The formula for calculating the momentum equation is:

[0176]

[0177] In the formula: p represents pressure, g represents the gravitational vector, and F i F i t These represent molecular stress and turbulent stress, respectively. i This represents the interphase momentum transfer per unit volume, (F int ) i It represents cohesion. This represents the fluid momentum source term, v i v j This represents the velocity corresponding to fluid phases i and j;

[0178] The formula for calculating the energy conservation equation is:

[0179]

[0180] In the formula: E i H represents the total energy. i This represents the total enthalpy, k. eff T represents the thermal conductivity. i D represents temperature. i This represents the viscous stress tensor, b i This represents the volume force vector, Q. ij This represents the interphase heat transfer rate. S represents the heat transfer rate from the interface between different fluid phases to fluid phase i. u This represents the fluid heat source term, h. i (T ij This indicates the interface temperature T. ij Enthalpy of the lower fluid phase i;

[0181] The formula for calculating the governing equation for energy transfer in a solid is as follows:

[0182]

[0183] In the formula: ρ represents the density of the solid, C p This represents specific heat, and T represents temperature. This represents the heat flux vector, v s S represents the solid convection velocity. u This represents the solid heat source term;

[0184] The heat transfer conservation equation between fluid and solid is:

[0185]

[0186] In the formula: λ represents the thermal conductivity of the solid, T represents the temperature of the solid, n represents the thickness of the solid, and h represents the convective heat transfer coefficient. w T represents the surface temperature of the solid. f This indicates the fluid temperature near the wall.

[0187] It should be noted that heat transfer between fluids and solids is based on the law of conservation of energy. After energy balance, the heat exchange per unit area should be equal, and the heat exchange at the interface between solids and fluids conforms to the third type of thermal boundary.

[0188] In existing technologies, due to the conservation equation of heat transfer between fluid and solid, the solid wall temperature T... w and near-wall fluid temperature T f All values ​​are preset, therefore, iterative calculations using two different models are required to obtain accurate flow and temperature field results. In this embodiment, the solid wall temperature T within the heat transfer conservation equation between the fluid and solid is used instead of preset values. w and near-wall fluid temperature T f All values ​​are measured in real time, which allows for direct iteration within the formula without the need for multiple substitution calculations between different models, resulting in shorter computation time and improved computational efficiency.

[0189] 204. By applying the boundary conditions and mathematical model to the physical model of the motor, the cooling flow field and temperature field of the motor are obtained.

[0190] Since the physical model of a motor can only reflect the structure of the motor, when mathematical simulation calculations are required based on the motor structure, the boundary conditions and the mathematical model corresponding to each computational domain need to be applied to the physical model of the motor. Through calculation and solution, the motor cooling flow field and the motor temperature field can be obtained.

[0191] The motor cooling flow field is simulated using the Volume-Of-Fluid (VOF) method to represent two-phase flow. Since current motor cooling methods are mainly oil-cooled, which involves two cooling media, oil and gas, the two phases are oil and ideal gas, respectively, when the motor cooling flow field is calculated using VOF to simulate two-phase flow.

[0192] When adding calculation boundaries, the fluid domain inlet is added as a boundary in the form of cooling oil flow rate, with the cooling oil volume fraction set to 1 and the ideal gas volume fraction set to 0; the fluid domain outlet is added as a boundary in the form of pressure. Motor loss data is added as heat to the solid domain containing the stator / rotor, windings, and magnets, and corresponding equivalent thermal resistance data is added to the winding interfaces (stator slots, end windings).

[0193] Based on the above steps, the motor cooling flow field and the motor temperature field can be obtained simultaneously. Figures 3(a) and 3(b) are schematic diagrams of the motor temperature field provided in the embodiments of this application. Figure 4 This is a schematic diagram of the motor cooling flow field provided in the embodiments of this application. As can be seen from the figures, Figures 3(a) and 3(b) can intuitively reflect the temperature distribution trend and the maximum temperature value of each component in the motor. The temperature field distribution trend can be used to analyze the uniformity and rationality of the temperature field, and the maximum temperature value can be used to assess whether the component temperature meets the design limit requirements. Figure 4 It can directly reflect the distribution of cooling oil on the windings, as well as the cooling capacity at different locations and the overall cooling uniformity. At the same time, by combining the flow field and the temperature field, on the one hand, the cooling capacity of the cooling scheme can be evaluated by the distribution of cooling oil, and on the other hand, the temperature field distribution of each component of the motor can further reflect the weak areas of the cooling scheme design, thereby guiding the optimization of the motor cooling scheme design.

[0194] In summary, the vehicle motor temperature simulation method provided in this application obtains the physical model and boundary conditions of the motor, determines a mathematical model based on the physical model, and then applies the boundary conditions and mathematical model to the physical model of the motor. Simultaneously, it solves for the motor cooling flow field and the motor temperature field, simplifying the calculation process and shortening the time required to obtain these fields. Furthermore, the vehicle motor temperature simulation method provided in this application allows for the simultaneous simulation of the motor cooling flow field and three-dimensional temperature field in a computer virtual environment during the digital prototype development stage. This provides a more comprehensive characterization of the factors influencing motor heat dissipation, enabling accurate assessment of the temperature field levels of various motor components and the feasibility of cooling solutions. Simultaneously, it allows for optimization of cooling solution design based on the temperature field results until development requirements are met, improving R&D efficiency.

[0195] Figure 5 This is a structural block diagram of a vehicle motor temperature simulation device provided in an embodiment of this application. See also... Figure 5 The device includes:

[0196] The first acquisition module 501 is used to acquire the physical model and boundary conditions of the motor, wherein the physical model is a volume mesh model;

[0197] Mathematical model determination module 502 is used to determine the mathematical model based on the physical model of the motor;

[0198] The solver module 503 is used to apply boundary conditions and mathematical models to the physical model of the motor to solve for the motor cooling flow field and the motor temperature field.

[0199] In the mathematical model, the solid wall temperature and the near-wall fluid temperature in the heat transfer conservation equation between the fluid and the solid are both measured in real time.

[0200] In some embodiments, the mathematical model includes the volume fraction conservation equation, the continuity equation, the momentum equation, the energy conservation equation, the energy transfer control equation within the solid, and the heat transfer conservation equation between the fluid and the solid.

[0201] The formula for calculating the volume fraction conservation equation is as follows:

[0202]

[0203] In the formula: n represents the number of fluid phases; α i This represents the volume fraction;

[0204] The formula for calculating the continuity equation is:

[0205]

[0206] In the formula: ρ i This represents density, v i It represents speed, m ij This represents the mass transfer rate from fluid phase i to fluid phase j, m ji This represents the mass transfer rate from fluid phase j to fluid phase i. This represents the fluid mass source term, where V represents volume, t represents time, and A represents area.

[0207] The formula for calculating the momentum equation is:

[0208]

[0209] In the formula: p represents pressure, g represents the gravitational vector, and F i F i t These represent molecular stress and turbulent stress, respectively. i This represents the interphase momentum transfer per unit volume, (F int ) i It represents cohesion. This represents the fluid momentum source term, v i v j This represents the velocity corresponding to fluid phases i and j;

[0210] The formula for calculating the energy conservation equation is:

[0211]

[0212] In the formula: E i H represents the total energy. i This represents the total enthalpy, k. eff T represents the thermal conductivity. i D represents temperature.i This represents the viscous stress tensor, b i This represents the volume force vector, Q. ij This represents the interphase heat transfer rate. S represents the heat transfer rate from the interface between different fluid phases to fluid phase i. u This represents the fluid heat source term, h. i (T ij This indicates the interface temperature T. ij Enthalpy of the lower fluid phase i;

[0213] The formula for calculating the governing equation for energy transfer in a solid is as follows:

[0214]

[0215] In the formula: ρ represents the density of the solid, C p This represents specific heat, and T represents temperature. This represents the heat flux vector, v s S represents the solid convection velocity. u This represents the solid heat source term;

[0216] The heat transfer conservation equation between fluid and solid is:

[0217]

[0218] In the formula: λ represents the thermal conductivity of the solid, T represents the temperature of the solid, n represents the thickness of the solid, and h represents the convective heat transfer coefficient. w T represents the surface temperature of the solid. f This indicates the fluid temperature near the wall.

[0219] In some embodiments, the device further includes:

[0220] The second acquisition module is used to acquire the assembly model of the motor;

[0221] The surface mesh model module is used to group and mesh the assembly model of the motor to obtain the surface mesh model;

[0222] The physical model module is used to divide the computational domain into surface meshes and volume meshes to obtain the physical model of the motor. The computational domain includes a solid domain, a fluid domain, and a rotating fluid domain. The rotating fluid domain has a rotation center, rotation direction, and rotation speed.

[0223] In some embodiments, the determining module includes:

[0224] Based on the physical model of the motor, a mathematical model is determined that corresponds one-to-one with the computational domain in the physical model of the motor.

[0225] In some embodiments, the boundary conditions include motor performance data, motor loss data, material properties of each component of the motor, and cooling flow rate of the motor.

[0226] In some embodiments, the boundary conditions include equivalent thermal resistance data, wherein the equivalent thermal resistance data is obtained by converting insulation data, wherein the insulation data includes insulation class, pure copper slot fill factor, silicon steel sheet stacking factor, paint thickness, insulating paper thickness, and welding coating thickness and width.

[0227] In some embodiments, the equivalent thermal resistance data includes stator / rotor core data, stator slot data, and end winding data.

[0228] The stator / rotor core data includes the core's axial equivalent thermal conductivity, and the formula for calculating the core's axial equivalent thermal conductivity is as follows:

[0229]

[0230] In the formula: λ T K represents the axial equivalent thermal conductivity of the iron core. Fe This represents the core stacking factor, δ. Fe δ0 represents the thickness of the core laminations, λ1 represents the thermal conductivity of the silicon steel sheet in the core, and λ0 represents the thermal conductivity of the insulating medium between the core laminations.

[0231] The stator slot data includes the thermal conductivity of the equivalent insulation layer. The formula for calculating the thermal conductivity of the equivalent insulation layer is:

[0232]

[0233] In the formula: λ q λ represents the thermal conductivity of the equivalent insulating layer. i This represents the thermal conductivity, δ. i This represents the thickness, and n represents the number of insulation categories;

[0234] The end winding data includes structural thermal resistance, which comprises a first structural thermal resistance and a second structural thermal resistance. The first structural thermal resistance is the material thermal resistance of the enamel coating, and the second structural thermal resistance is the material thermal resistance of both the enamel coating and the coating layer.

[0235] The formula for calculating the thermal resistance of the first structure is:

[0236]

[0237] In the formula: R1 represents the thermal resistance of the first structure, δ1 represents the material thickness of the paint, and λ1 represents the thermal conductivity of the paint material.

[0238] The formula for calculating the thermal resistance of the second structure is:

[0239]

[0240] In the formula: R2 represents the thermal resistance of the second structure, ΔR represents the thermal resistance of the coating material, δ2 represents the material thickness of the coating, and λ2 represents the thermal conductivity of the coating material.

[0241] It should be noted that the vehicle motor temperature simulation device provided in the above embodiments is only illustrated by the division of the functional modules described above. In actual applications, the functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. Furthermore, the vehicle motor temperature simulation device and the vehicle motor temperature simulation method embodiments provided in the above embodiments belong to the same concept, and their specific implementation process can be found in the method embodiments, which will not be repeated here.

[0242] The vehicle motor temperature simulation device provided in this application obtains the physical model and boundary conditions of the motor, determines the mathematical model based on the physical model of the motor, and then applies the boundary conditions and mathematical model to the physical model of the motor. At the same time, the motor cooling flow field and motor temperature field are solved, which simplifies the calculation process and shortens the time for obtaining the motor cooling flow field and motor temperature field.

[0243] In an exemplary embodiment, a computer-readable storage medium is also provided, such as a memory including program code that can be executed by a processor in an electronic device to perform the vehicle motor temperature simulation method in the above embodiments. For example, the computer-readable storage medium may be a read-only memory (ROM), a random access memory (RAM), a compact disc read-only memory (CD-ROM), magnetic tape, floppy disk, and optical data storage device, etc.

[0244] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only.

[0245] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A method of simulating temperature of an electric machine of a vehicle, characterized by, The method comprises: acquiring a physical model and boundary conditions of the motor, wherein the physical model is a volume mesh model; determining a mathematical model based on the physical model of the motor; applying the boundary conditions and the mathematical model to the physical model of the motor to obtain a motor cooling flow field and a motor temperature field by solving; wherein the solid wall surface temperature in the heat transfer conservation equation between the fluid and the solid in the mathematical model and the near-wall fluid temperature are real-time measured values; the mathematical model comprises a volume fraction conservation equation, a continuity equation, a momentum equation, an energy conservation equation, a solid internal energy transmission control equation and a heat transfer conservation equation between the fluid and the solid, wherein the calculation formula of the volume fraction conservation equation is: wherein: n represents the number of fluid phases; φ represents the volume fraction; the calculation formula of the continuity equation is: wherein: denotes the density, denotes the velocity, denotes the mass transfer rate from the fluid phase to the fluid phase , denotes the mass transfer rate from the fluid phase to the fluid phase , denotes the fluid mass source term, denotes the volume, denotes the time, denotes the area; the calculation formula of the momentum equation is: wherein: represents the pressure, represents the gravity vector, , represent the molecular and turbulent stresses, respectively, represents the interphase momentum transfer per unit volume, represents the cohesive force, represents the fluid momentum source term, , represents the fluid phase , corresponding velocity; the calculation formula of the energy conservation equation is: where: represents the total energy, represents the total enthalpy, represents the thermal conductivity, represents the temperature, represents the viscous stress tensor, represents the body force vector, represents the interfacial heat transfer rate, represents the interfacial heat transfer rate between different fluid phases, represents the interfacial heat transfer rate between different fluid phases, represents the fluid heat source term, represents the enthalpy of the fluid phase at the interfacial temperature, represents the enthalpy of the fluid phase at the interfacial temperature, represents the enthalpy of the fluid phase at the interfacial temperature. the calculation formula of the solid internal energy transmission control equation is: wherein: represents the solid density, represents the specific heat, represents the temperature, represents the heat flux vector, represents the solid convection velocity, represents the solid heat source term; the heat transfer conservation equation between the fluid and the solid is: wherein: represents the solid thermal conductivity, represents the solid temperature, represents the solid thickness, represents the convective heat transfer coefficient, represents the solid wall temperature, represents the near-wall fluid temperature.

2. The method of simulating temperature of a vehicle electric machine according to claim 1, wherein, Before the acquiring the physical model of the motor, the method further comprises: acquiring an assembly model of the motor; grouping and surface mesh dividing the assembly model of the motor to obtain a surface mesh model; segmenting a calculation domain and volume mesh dividing the surface mesh model to obtain the physical model of the motor, wherein the calculation domain comprises a solid domain, a fluid domain and a rotating fluid domain, and the rotating fluid domain has a rotating center, a rotating direction and a rotating speed.

3. The method of simulating temperature of a vehicle electric machine according to claim 2, wherein, The determining a mathematical model based on the physical model of the motor comprises: determining a mathematical model corresponding to the calculation domain in the physical model of the motor based on the physical model of the motor.

4. The method of simulating temperature of a vehicle electric machine according to claim 1, wherein, The boundary conditions comprise motor performance data, motor loss data, material properties of each component of the motor and cooling flow rate of the motor.

5. The method of simulating temperature of a vehicle electric machine according to claim 1, wherein, The boundary conditions comprise equivalent thermal resistance data, which is obtained by converting insulation data, wherein the insulation data comprises insulation grade, pure copper slot fullness, silicon steel sheet stacking coefficient, paint thickness, insulation paper thickness, welding paint thickness and width.

6. The method of simulating temperature of a vehicle electric machine according to claim 5, wherein, The equivalent thermal resistance data comprises stator / rotor core data, stator slot data and end winding data, wherein the stator / rotor core data comprises an axial equivalent thermal conductivity of the core, and the calculation formula of the axial equivalent thermal conductivity of the core is: In the formula: represents the axial equivalent thermal conductivity of the core, represents the lamination factor of the core, represents the core lamination thickness, represents the inter-lamination insulation medium thickness of the core, represents the thermal conductivity of the core silicon steel sheet, represents the thermal conductivity of the inter-lamination insulation medium of the core; the stator slot data comprises a thermal conductivity of an equivalent insulation layer, and the calculation formula of the thermal conductivity of the equivalent insulation layer is: In the formula: represents the thermal conductivity of the equivalent insulation layer, represents the thermal conductivity, represents the thickness, and n represents the number of insulation categories. the end winding data comprises a structural thermal resistance, and the structural thermal resistance comprises a first structural thermal resistance and a second structural thermal resistance, wherein the first structural thermal resistance is a material thermal resistance of paint, and the second structural thermal resistance is a material thermal resistance of paint and coating, the calculation formula of the first structural thermal resistance is: In the formula: represents the first structure thermal resistance, represents the material thickness of the paint skin, represents the material thermal conductivity of the paint skin; the calculation formula of the second structural thermal resistance is: In the formula: represents the second structure thermal resistance, represents the material thermal resistance of the coating layer, represents the material thickness of the coating layer, represents the material thermal conductivity of the coating layer.

7. An apparatus for simulating temperature of a vehicle electric machine, characterized by The device comprises: a first acquiring module configured to acquire a physical model and boundary conditions of the motor, wherein the physical model is a volume mesh model; a mathematical model determining module configured to determine a mathematical model based on the physical model of the motor; a solving module configured to apply the boundary conditions and the mathematical model to the physical model of the motor to obtain a motor cooling flow field and a motor temperature field by solving. The wall surface temperature of the solid and the near-wall surface fluid temperature in the heat transfer conservation equation between the fluid and the solid in the mathematical model are real-time measured values; the mathematical model comprises a volume fraction conservation equation, a continuity equation, a momentum equation, an energy conservation equation, a solid internal energy transfer control equation and a heat transfer conservation equation between the fluid and the solid, The calculation formula of the volume fraction conservation equation is: wherein: n represents the number of fluid phases; φ represents the volume fraction; The calculation formula of the continuity equation is: wherein: denotes the density, denotes the velocity, denotes the mass transfer rate from the fluid phase to the fluid phase , denotes the mass transfer rate from the fluid phase to the fluid phase , denotes the fluid mass source term, denotes the volume, denotes the time, denotes the area; The calculation formula of the momentum equation is: wherein: represents the pressure, represents the gravity vector, , respectively represent the molecular stress and the turbulent stress, represents the interphase momentum transfer per unit volume, represents the cohesive force, represents the fluid momentum source term, , represents the fluid phase , the corresponding velocity; The calculation formula of the energy conservation equation is: wherein: represents the total energy, represents the total enthalpy, represents the thermal conductivity, represents the temperature, represents the viscous stress tensor, represents the volume force vector, represents the interfacial heat transfer rate, represents the heat transfer rate from the interface to the fluid phase , represents the fluid heat source term, represents the enthalpy of the fluid phase at the interface temperature ; The calculation formula of the solid internal energy transfer control equation is: where: represents the solid density, represents the specific heat, represents the temperature, represents the heat flux vector, represents the solid convection velocity, represents the solid heat source term; The heat transfer conservation equation between the fluid and the solid is: wherein: represents the solid thermal conductivity, represents the solid temperature, represents the solid thickness, represents the convective heat transfer coefficient, represents the solid wall temperature, represents the near-wall fluid temperature.

8. A storage medium, characterized by When the instructions in the storage medium are executed by the processor of the electronic device, the electronic device can execute the simulation method of the vehicle motor temperature as claimed in any one of claims 1 to 6.

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