Optimization method for conductor size and stator slot height of flat wire motor based on electromagnetic thermal coupling analysis

Abstract

The invention discloses a flat wire motor conductor size and stator slot height optimization method based on electromagnetic thermal coupling analysis. The method comprises the following steps: establishing a motor electromagnetic field and temperature field simplified model, parameterizing motor basic data, and setting an optimization interval of the conductor size and the stator slot height; calculating stator winding loss through iterative electromagnetic field simulation by taking the average torque as a constraint condition, inputting alternating current loss as a heat source into a temperature field for simulation, and updating material parameters until the temperature is converged; and finally, selecting a scheme with the minimum alternating current loss as an optimization result. According to the method, the calculation efficiency is improved through equivalent conductor model simplified analysis and convergence tolerance setting, multi-parameter collaborative optimization is achieved through the genetic algorithm, temperature distribution under the actual working condition can be accurately predicted, alternating current loss is effectively reduced, and an efficient and reliable optimization means is provided for design of the high-speed permanent magnet synchronous motor.

Description

Technical Field

[0001] The present invention belongs to the technical field of optimized design of flat wire motor windings, and relates to an optimization method for the conductor size and stator slot height of a flat wire motor based on electromagnetic-thermal coupling analysis. Background Art

[0002] With the rapid development of electric vehicle technology and the pursuit of high efficiency, high torque, and high speed performance, permanent magnet synchronous motors have become the first choice for electric vehicle traction motors due to their low iron loss and high power density. Among them, flat wire permanent magnet synchronous motors have attracted much attention due to their superior electromagnetic performance, high power density, and NVH improvement. However, with the development of motors towards high power density and high speed, the AC losses of the stator windings and the resulting temperature rise have increased significantly, seriously affecting the operating efficiency and performance. Therefore, the optimized design of the stator windings is particularly important. Existing optimized design methods mostly rely on the finite element method, with high computational complexity and low iteration efficiency, making it difficult to balance engineering applications and performance optimization. Summary of the Invention

[0003] Object of the Invention: The object of the present invention is to provide an optimization method for the conductor size and stator slot height of a flat wire motor based on electromagnetic-thermal coupling analysis, aiming to reduce the AC losses of the flat wire motor and improve the working efficiency of the flat wire motor on the premise of ensuring the average torque of the flat wire motor remains unchanged.

[0004] Technical Solution: The optimization method for the conductor size and stator slot height of a flat wire motor based on electromagnetic-thermal coupling analysis according to the present invention includes the following steps:

[0005] (1) Establish a parametric electromagnetic field simplified model and a temperature field simplified model of the flat wire motor and set the initial temperature;

[0006] (2) Conduct electromagnetic field simulation to calculate the AC losses of the stator windings, stator iron losses, rotor iron losses, and average torque of the flat wire motor;

[0007] (3) Use the AC losses of the stator windings, stator iron losses, and rotor iron losses of the flat wire motor as the heat source input for the temperature field simplified model of the flat wire motor, and use a static solver to perform temperature field simulation on the temperature field simplified model of the flat wire motor to calculate the temperature of the flat wire motor;

[0008] (4) According to the temperature of the flat wire motor in step (3), reset the material properties of the electromagnetic materials of the flat wire motor in the parametric electromagnetic field simplified model of the flat wire motor;

[0009] (5) Repeat steps (2) to (4) until the temperature of the flat wire motor converges;

[0010] (6) Set the dimensions of the stator conductors and the stator slot height of the flat wire motor as optimization variables, determine their optimization intervals, and at the same time set the minimum AC loss of the flat wire motor as the optimization goal and the unchanged average torque as the constraint condition;

[0011] (7) Conduct optimization to obtain the optimal values of the stator conductor dimensions and the stator slot height of the flat wire motor.

[0012] Furthermore, in step (1), draw the 2D models of the stator, rotor, winding and other components of the flat wire motor to be optimized in Ansys Maxwell, and set the geometric dimensions and material properties of the components as parameters. Add winding current or voltage excitation, set the boundary conditions of the solution region, and perform mesh division according to specific conditions to complete the establishment of the parametric electromagnetic field simplified model of the flat wire motor. At the same time, draw the 3D model of the flat wire motor in Ansys Thermal. The 3D model includes the flat wire motor body and its heat dissipation system. Set the material properties of each component, the forced heat dissipation coefficient of the main heat dissipation components and other parameters, and perform mesh division according to specific conditions to complete the establishment of the temperature field simplified model of the flat wire motor.

[0013] Furthermore, in step (2), the AC loss of the stator winding is calculated by the analytical method, and its calculation formula is as follows:

[0014] P AC =K AC P DC

[0015] Among them, P AC is the winding AC loss, P DC is the DC resistance loss, K AC is the AC loss coefficient, and its calculation formula is:

[0016]

[0017] Among them, l refers to the l-th layer of the stator winding, N is the number of conductor turns above the l-th layer, is the ampere-turns above the l-th layer, N l is the number of parallel conductors in the l-th layer, I is the current in the conductors of the l-th layer, C I (η) and C II The calculation formulas of (η) are:

[0018]

[0019] Among them, η is the characteristic height of the conductor, ε l is the filling factor of the l-th layer of the conductor, δ is the skin depth, h " is the conductor height, h $ is the conductor width, w lis the stator slot width, σ is the conductor conductivity, ω ) is the current angular frequency, μ + is the magnetic permeability in vacuum.

[0020] Furthermore, in step (3), the heat source type adopts internal heat generation, and the formula for its parameter size is:

[0021]

[0022] where P , is the internal heat generation parameter size of the heat source, P is the power of the heat source element, and V is the volume of the heat source element.

[0023] Furthermore, in step (4), the calculation formulas for the key electromagnetic material parameters of the flat wire motor are as follows:

[0024] The calculation formula for the conductivity of the stator winding material is:

[0025] σ(T) = σ + [1 + α(T - T + )]

[0026] where σ(T) is the conductivity at temperature T, σ + is the conductivity at the reference temperature, α is the temperature coefficient of the stator winding material, and T + is the reference temperature;

[0027] The calculation formula for the remanent magnetic flux density is:

[0028] Br(T) = Br + [1 + α 45 (T - T + )]

[0029] where Br(T) is the remanent magnetic flux density at temperature T, Br + is the remanent magnetic flux density at the reference temperature, α 45 is the remanent magnetic temperature coefficient, and T + is the reference temperature;

[0030] The calculation formula for the intrinsic coercive force is:

[0031] Hc(T) = Hc + [1 + α 7" (T - T + )]

[0032] where Hc(T) is the remanent magnetic flux density at temperature T, Hc + is the remanent magnetic flux density at the reference temperature, α 7" is the intrinsic coercive force temperature coefficient, and T + is the reference temperature.

[0033] Further, in step (5), the tolerance for the convergence of the flat wire motor temperature is set to 0.5%.

[0034] Further, the response surface method is adopted. According to the Latin hypercube sampling design method, the average torque and AC losses under parameter combinations of different conductor sizes and stator slot heights are recorded. A response surface model of the simplified electromagnetic field model of the flat wire motor is established, and the genetic algorithm optimization function in Ansys Maxwell software is used to globally optimize the conductor size and stator slot height of the flat wire motor. The basic mathematical expression of the response surface model is as follows:

[0035]

[0036] where y is the estimated value of the target response, β + 、β ； 、β ；； 、β ；j are all regression coefficients, m is the number of variables, x ； represents the i-th variable, x j represents the j-th variable, and ε is the error.

[0037] The system corresponding to the method includes

[0038] A simplified model establishment and initialization unit, which is used to establish a parameterized electromagnetic field simplified model and a temperature field simplified model of the flat wire motor, and set the initial temperature;

[0039] An electromagnetic field simulation unit, which is used to perform electromagnetic field simulation and calculate the AC losses, stator iron losses, rotor iron losses and average torque of the flat wire motor stator winding;

[0040] A temperature field simulation unit, which is used to use the AC losses, stator iron losses and rotor iron losses of the flat wire motor stator winding as the heat source input of the temperature field simplified model of the flat wire motor, use a static solver to perform temperature field simulation on the temperature field simplified model of the flat wire motor, and calculate the temperature of the flat wire motor; according to the temperature of the flat wire motor, reset the material properties of the electromagnetic materials of the flat wire motor in the parameterized electromagnetic field simplified model of the flat wire motor; repeat the electromagnetic field simulation and temperature field simulation to make the temperature of the flat wire motor converge;

[0041] An optimization variable, optimization target and constraint condition setting unit, which is used to set the stator conductor size and stator slot height of the flat wire motor as optimization variables, determine their optimization intervals, and at the same time set the minimum AC loss of the flat wire motor as the optimization target and the unchanged average torque as the constraint condition;

[0042] A scheme optimization unit, which is used to obtain the optimal values of the stator conductor size and stator slot height of the flat wire motor.

[0043] The electronic device according to the present invention includes a memory and a processor, wherein:

[0044] A memory for storing a computer program capable of running on a processor;

[0045] A processor for performing the steps of the optimization method of the conductor size and stator slot height of the flat wire motor based on electromagnetic-thermal coupling analysis when running the computer program.

[0046] The computer-readable storage medium of the present invention stores computer instructions, which are used to perform the steps of the optimization method of the conductor size and stator slot height of the flat wire motor based on electromagnetic-thermal coupling analysis when the computer instructions are called.

[0047] The computer program product of the present invention includes a computer program or instructions, and when the computer program or instructions are executed by a processor, the steps of the optimization method of the conductor size and stator slot height of the flat wire motor based on electromagnetic-thermal coupling analysis are implemented.

[0048] Beneficial effects: Compared with the prior art, the remarkable technical effects of the present invention are as follows: By combining the simplified finite element model analysis method with the analytical method, the AC loss and stator-rotor iron loss of the flat wire motor are obtained, and then they are set as the heat sources of the temperature field finite element model for electromagnetic-thermal field coupling analysis, and based on this, the conductor size of the stator winding and the stator slot height of the flat wire motor are optimized. This method can accurately calculate the temperature under the actual working conditions of the flat wire motor and effectively reduce the AC loss of the flat wire motor, thereby improving the working efficiency of the flat wire motor and providing a certain reference for the optimized design of the stator winding of the flat wire motor. Description of the Drawings

[0049] Figure 1 is a flowchart of the optimization method of the conductor size and stator slot height of the flat wire motor based on electromagnetic-thermal coupling analysis;

[0050] Figure 2 is a quarter model diagram of the simplified electromagnetic field model of the flat wire motor;

[0051] Figure 3 is a simplified model diagram of the temperature field of the flat wire motor;

[0052] Figure 4 is a waveform diagram of the stator and rotor iron losses of the flat wire motor under rated operation;

[0053] Figure 5 is a waveform diagram of the electromagnetic torque of the flat wire motor under rated operation;

[0054] Figure 6 is a fitting surface of the average torque and conductor size of the flat wire motor under rated operation;

[0055] Figure 7 is a corresponding curve of the average torque and stator slot height of the flat wire motor under rated operation;

[0056] Figure 8 It is a quarter model diagram of the optimized simplified electromagnetic field model of the flat wire motor;

[0057] Figure 9 It is a comparison diagram of the electromagnetic torque waveforms of the flat wire motor before and after optimization during rated operation;

[0058] Figure 10 It is a comparison diagram of the AC losses of the flat wire motor before and after optimization at different speeds;

[0059] Figure 11 It is a comparison diagram of the stator and rotor iron losses of the flat wire motor before and after optimization at different speeds. Specific implementation manner

[0060] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0061] Through the coupled simulation of the electromagnetic field and the temperature field, combined with genetic algorithm optimization, the present invention reduces the AC loss of the stator winding and improves the efficiency of the flat wire motor on the premise of ensuring the same average torque of the flat wire motor. The specific steps include: establishing a parametric electromagnetic field of the flat wire motor and a simplified model of the temperature field of the flat wire motor; performing electromagnetic field simulation to calculate the AC loss, stator iron loss, rotor iron loss and electromagnetic torque of the flat wire motor; using the AC loss, stator iron loss and rotor iron loss of the flat wire motor stator winding as the heat source of the simplified model of the flat wire motor temperature field, using a static solver to perform temperature field simulation on the simplified model of the flat wire motor temperature field, and calculating the temperature of the flat wire motor; repeating the iteration until the temperature converges to obtain the steady-state operating temperature of the flat wire motor; setting optimization variables, optimization objectives and constraint conditions; obtaining the optimal solution of the optimization variables. The present invention simplifies the analysis through an equivalent conductor model, sets a convergence tolerance (0.5%) to improve the calculation efficiency, and realizes multi-parameter collaborative optimization by combining the response surface method and the genetic algorithm, can accurately predict the temperature distribution under actual working conditions, effectively reduce the AC loss, and provide an efficient and reliable optimization method for the design of the flat wire motor.

[0062] As Figure 1 shown, the optimization method of the conductor size and stator slot height of the flat wire motor based on electromagnetic-thermal coupling analysis according to the present invention is described in detail in the following implementation steps:

[0063] (1) Establish a parametric simplified electromagnetic field model of the flat wire motor and a simplified temperature field model of the flat wire motor and set the initial temperature;

[0064] In this embodiment, a 2D model of the stator, rotor, winding and other components of the flat wire motor to be optimized is drawn in Ansys Maxwell, and the geometric dimensions and material properties of the components are set as parameters. Add winding current excitation and set the boundary conditions of the solution region.

[0065] Mesh generation is carried out according to specific conditions, specifically: the mesh length is used as the mesh characteristic size for mesh generation to complete the establishment of the parametric electromagnetic field simplified model of the flat wire motor.

[0066] At the same time, a 3D model of the flat wire motor is drawn in Ansys Thermal. The 3D model includes the flat wire motor body and its water-cooled heat dissipation system. To simplify the model and reduce the simulation time, the conductors in the stator winding part of the flat wire motor are replaced by a single equivalent conductor. Parameters such as the material properties of each component and the forced heat dissipation coefficient of the main heat dissipation components are set. Among them, the stator winding material is set as copper, the flat wire motor housing and the spiral water channel material are set as aluminum, the stator and rotor materials of the flat wire motor are set as 27sw1400 silicon steel sheets, and the permanent magnet material is set as N52 magnet steel.

[0067] Mesh generation is carried out according to specific conditions to complete the establishment of the simplified temperature field model of the flat wire motor.

[0068] As Figure 2 shown is a quarter model diagram of the established simplified electromagnetic field model of the flat wire motor, Figure 3 shown is the diagram of the established simplified temperature field model of the flat wire motor.

[0069] In this example, the initial temperature is set to 20 °C, and the corresponding material properties are the values at 20 °C.

[0070] The basic parameters of the motor are shown in Table 1;

[0071] Table 1 Basic parameters of the flat wire motor

[0072] Name Value Stator Outer Diameter (mm) 90.0 Stator Inner Diameter (mm) 63.8 Rotor Outer Diameter (mm) 62.8 Rotor Inner Diameter (mm) 26.5 Air Gap Width (mm) 1.0 Number of Stator Slots 48 Number of Poles 4 Stator Slot Dimensions (mm×mm) 13.06×4.41 Number of Conductors per Slot 7 Conductor Dimensions (mm×mm) 1.37×4.13 Axial Length (mm) 80 Rated Speed (rpm) 6000

[0073] (2) Conduct electromagnetic field simulation to calculate the AC loss, stator iron loss, rotor iron loss and average torque of the stator winding of the flat wire motor. Among them, the stator iron loss, rotor iron loss and electromagnetic torque of the flat wire motor are as Figure 4 and Figure 5 shown. The AC loss of the stator winding is calculated by the analytical method, and its calculation formula is as follows:

[0074] P AC =K AC P DC (1)

[0075] Among them, P AC is the AC loss of the stator winding, P DC is the DC resistance loss, and K AC is the AC loss coefficient, and its calculation formula is:

[0076]

[0077] Among them, l is the l-th layer of the specified sub-winding, N is the number of turns of the conductor above the l-th layer, is the number of ampere-turns above the l-th layer, N l is the number of parallel conductors in the l-th layer, I is the current in the conductor of the l-th layer, C I (η) and C II (η) are two polynomial coefficients of the AC loss coefficient, and the calculation formula is:

[0078]

[0079] Among them, η is the characteristic height of the conductor, ε l is the filling factor of the l-th layer of the conductor, δ is the skin depth, h " is the height of the conductor, h $ is the width of the conductor, w l is the width of the stator slot, σ is the conductivity of the conductor, ω ) is the angular frequency of the current, μ + is the magnetic permeability in vacuum.

[0080] After calculation, when the winding current density is 26.5 A / mm 2 , and the initial temperature is 20 °C, the stator iron loss of the flat wire motor is 295 W, while the rotor iron loss is about 13.4 W. At the same time, the electromagnetic torque is 159 Nm, and the AC loss of the stator winding is 3.1 kW.

[0081] (3) Take the AC loss of the stator winding, stator iron loss and rotor iron loss of the flat wire motor as the heat source input of the simplified temperature field model of the flat wire motor, use the static solver to perform temperature field simulation on the simplified temperature field model of the flat wire motor, and calculate the temperature of the flat wire motor;

[0082] The heat source type adopts internal heat generation, and its parameter size formula is:

[0083]

[0084] Among them, P , is the parameter size of the internal heat generation of the heat source, P is the power of the heat source element, and V is the volume of the heat source element.

[0085] The calculated parameter size of the internal heat generation of the heat source is shown in Table 2.

[0086] Table 2 Parameter of Internal Heat Generation of Heat Source

[0087]

[0088]

[0089] (4) Reset the material properties of the electromagnetic materials of the flat wire motor in the simplified parametric electromagnetic field model of the flat wire motor according to the temperature of the flat wire motor in step (3). The electromagnetic material parameters of the flat wire motor include the conductivity of the stator winding material, the remanent magnetic induction intensity and the intrinsic coercive force of the permanent magnet;

[0090] The conductivity calculation formula of the stator winding material is:

[0091] σ(T) = σ + [1 + α(T - T + )] (9)

[0092] where σ(T) is the conductivity of the stator winding material when the stator winding temperature is T, σ + is the conductivity of the stator winding material at the reference temperature, α is the temperature coefficient of the stator winding material, and T + is the reference temperature;

[0093] In this embodiment, copper is selected as the stator winding material. Then the conductivity calculation formula of copper is:

[0094] σ CK (T) = σ CK+ [1 + α CK (T - T + )] (10)

[0095] where σ CK (T) is the conductivity of copper when the stator winding temperature is T, σ CK+ is the conductivity of copper at the reference temperature, α CK is the temperature coefficient of copper, and T + is the reference temperature.

[0096] The calculation formula for the remanent magnetic induction intensity is:

[0097] Br(T) = Br + [1 + α 45 (T - T + )] (11)

[0098] where Br(T) is the remanent magnetic induction intensity of the permanent magnet at temperature T, Br + is the remanent magnetic induction intensity at the reference temperature, α 45 is the remanent magnetic temperature coefficient, and T + is the reference temperature.

[0099] The calculation formula for the intrinsic coercive force is:

[0100] Hc(T) = Hc + [1 + α 7" (T - T + )] (12)

[0101] Among them, Hc(T) is the intrinsic coercivity of the permanent magnet at temperature T, and Hc + is the intrinsic coercivity of the permanent magnet at the reference temperature, and α 7" is the temperature coefficient of the intrinsic coercivity, and T + is the reference temperature.

[0102] (5) Repeat steps (2) to (4) to make the temperature of the flat wire motor converge.

[0103] The temperature convergence tolerance of the flat wire motor is set to 0.5%.

[0104] After multiple iterations, the average temperature of some components of the flat wire motor is shown in Table 3.

[0105] Table 3 Average Temperature of Some Components of the Flat Wire Motor

[0106]

[0107]

[0108] (6) Set the stator conductor size and stator slot height of the flat wire motor as optimization variables, determine their optimization intervals, and at the same time set the minimum AC loss of the stator winding of the flat wire motor as the optimization goal and the constant average torque as the constraint condition.

[0109] In principle, the setting of the optimization interval should not exceed the geometric limit range of the corresponding components. The larger the included range, the more comprehensive the optimization range.

[0110] (7) Conduct optimization to obtain the optimal values of the stator conductor size and stator slot height of the flat wire motor;

[0111] In the embodiment of the present invention, the response surface method is adopted. According to the Latin hypercube sampling design method, the average torque and AC loss are recorded under the parameter combinations of different conductor sizes and stator slot heights, the relationship between the constraint conditions and the optimization variables is obtained, the response surface model of the simplified electromagnetic field model of the flat wire motor is established, and the genetic algorithm optimization function in Ansys Maxwell software is used to globally optimize the conductor size and stator slot height of the flat wire motor; as Figure 6 and Figure 7 shown, the specific mathematical expression of the average torque is:

[0112] T5 = 159.73207 - 3.34143×h " - 2.48464×h $ + 2.37250×w l + 0.09019×h " ×

[0113] h $ - 0.30988×h" ×w l -0.13464×h $ ×w l +0.19191×h " 2 +0.26526×h $ 2 -0.36072×w l 2 +ε + (13)

[0114] where T5 is the average torque, h " is the conductor height, h $ is the conductor width, w l is the stator slot height, ε + is the error.

[0115] The basic mathematical expression of the response surface model is:

[0116]

[0117] where y is the estimated value of the target response, β + , β ； , β ；； , β ；j are all regression coefficients, m is the number of variables, x ； represents the i-th variable, x j represents the j-th variable, x is a set of m-dimensional vectors, and ε is the error.

[0118] Use the genetic algorithm optimization function in Ansys Maxwell software to perform global optimization based on the response surface model to find the conductor size and stator slot height with the minimum AC loss of the stator winding. The results are shown in Table 3.

[0119] Table 3 Optimization variable ranges and magnitudes

[0120]

[0121]

[0122] Adopt this scheme, the electromagnetic field model of the flat wire motor after optimization is as Figure 8 shown, and the electromagnetic torque, winding AC loss, and stator and rotor iron losses of the flat wire motor before and after optimization are compared. As Figures 9 to 11As shown, it can be found that the electromagnetic torque and stator-rotor iron losses of the flat wire motor remain basically unchanged before and after optimization. For the AC losses of the winding, at lower speeds, the reduction in the AC losses of the optimized winding is relatively large. However, when the speed increases, the reduction amplitude gradually decreases, and when the speed is 9500 rpm, the AC losses before and after optimization are basically the same. After comparison, under rated operating conditions, the AC losses after optimization are reduced by 2.78% compared to before optimization. This indicates that the optimization scheme can effectively reduce the AC losses of the winding, thereby reducing the temperature rise of the flat wire motor.

[0123] The system corresponding to the method includes

[0124] A simplified model establishment and initialization unit, which is used to establish a parameterized electromagnetic field simplified model and a temperature field simplified model of the flat wire motor, and set the initial temperature;

[0125] An electromagnetic field simulation unit, which is used to perform electromagnetic field simulation, and calculate the AC losses of the stator winding, stator iron loss, rotor iron loss and average torque of the flat wire motor;

[0126] A temperature field simulation unit, which is used to use the AC losses of the stator winding, stator iron loss and rotor iron loss of the flat wire motor as the heat source input of the temperature field simplified model of the flat wire motor, and use a static solver to perform temperature field simulation on the temperature field simplified model of the flat wire motor to calculate the temperature of the flat wire motor; according to the temperature of the flat wire motor, reset the material properties of the electromagnetic materials of the flat wire motor in the parameterized electromagnetic field simplified model of the flat wire motor; repeat the electromagnetic field simulation and temperature field simulation to make the temperature of the flat wire motor converge;

[0127] An optimization variable, optimization objective and constraint condition setting unit, which is used to set the stator conductor size and stator slot height of the flat wire motor as optimization variables, determine their optimization intervals, and at the same time set the minimum AC loss of the flat wire motor as the optimization objective and the unchanged average torque as the constraint condition;

[0128] A scheme optimization unit, which is used to obtain the optimal values of the stator conductor size and stator slot height of the flat wire motor.

[0129] The electronic device of the present invention includes a memory and a processor, wherein:

[0130] The memory is used to store a computer program that can run on the processor;

[0131] The processor is used to execute the steps of the optimization method for the conductor size and stator slot height of the flat wire motor based on electromagnetic-thermal coupling analysis when running the computer program.

[0132] The computer-readable storage medium of the present invention stores computer instructions, which are used to execute the steps of the optimization method for the conductor size and stator slot height of the flat wire motor based on electromagnetic-thermal coupling analysis when the computer instructions are called.

[0133] The computer program product of the present invention includes a computer program or instructions, and when the computer program or instructions are executed by a processor, the steps of the optimization method for the conductor size and stator slot height of the flat wire motor based on electromagnetic-thermal coupling analysis are implemented.

Claims

1. An optimization method for the conductor size and stator slot height of a flat wire motor based on electromagnetic-thermal coupling analysis, characterized in that: It includes the following steps: (1) Establish a simplified parametric electromagnetic field model and a simplified temperature field model of the flat wire motor and set the initial temperature; (2) Conduct electromagnetic field simulation to calculate the AC loss of the stator winding, stator iron loss, rotor iron loss and average torque of the flat wire motor; (3) Use the AC loss of the stator winding, stator iron loss and rotor iron loss of the flat wire motor as the heat source input of the simplified temperature field model of the flat wire motor. Use a static solver to perform temperature field simulation on the simplified temperature field model of the flat wire motor and calculate the temperature of the flat wire motor; (4) According to the temperature of the flat wire motor in step (3), reset the material properties of the electromagnetic materials of the flat wire motor in the simplified parametric electromagnetic field model of the flat wire motor; (5) Repeat steps (2) to (4) until the motor temperature converges; (6) Set the stator conductor size and stator slot height of the flat wire motor as optimization variables, determine their optimization intervals, and at the same time set the minimum AC loss of the stator winding of the flat wire motor as the optimization goal and the unchanged average torque as the constraint condition; (7) Perform optimization to obtain the optimal values of the stator conductor size and stator slot height of the flat wire motor.

2. The optimization method for the conductor size and stator slot height of a flat wire motor based on electromagnetic-thermal coupling analysis according to claim 1, characterized in that: In step (1), draw the 2D model of each component of the flat wire motor to be optimized in Ansys Maxwell, and set the component geometric dimensions and their material properties as parameters; add winding current or voltage excitation, set the boundary conditions of the solution area, and perform mesh division according to specific conditions to complete the establishment of the simplified parametric electromagnetic field model of the flat wire motor; at the same time, draw the 3D model of the flat wire motor in Ansys Thermal. The 3D model includes the flat wire motor body and its heat dissipation system. Set the material properties of each component and the forced heat dissipation coefficient of the main heat dissipation components, and perform mesh division according to specific conditions to complete the establishment of the simplified temperature field model of the flat wire motor.

3. An optimization method for the conductor size and stator slot height of a flat wire motor based on electromagnetic-thermal coupling analysis according to claim 1, characterized in that: In step (2), the AC loss of the stator winding is calculated by the analytical method, and its calculation formula is as follows: P AC = K AC P DC Among them, P AC is the AC loss of the stator winding, and P DC is the DC resistance loss. K AC is the AC loss coefficient, and its calculation formula is: where l is the l-th layer of the specified sub-winding, N is the number of turns of the conductor above the l-th layer, is the ampere-turns above the l-th layer, N l is the number of parallel conductors in the l-th layer, I is the current in the conductor of the l-th layer, C I (η) and C II (η) are calculated as follows: Among them, η is the characteristic height of the conductor, ε l is the filling factor of the l-th layer of the conductor, δ is the skin depth, h c is the height of the conductor, h w is the width of the conductor, w l is the width of the stator slot, σ is the conductivity of the conductor, ω e is the angular frequency of the current, and μ0 is the magnetic permeability in vacuum.

4. An optimization method for the conductor size and stator slot height of a flat wire motor based on electromagnetic-thermal coupling analysis according to claim 1, characterized in that: In step (3), the heat source type is internal heat generation, and its parameter size formula is: where P v is the magnitude of the internal heat generation parameter of the heat source, P is the power of the heat source element, and V is the volume of the heat source element.

5. An optimization method for the conductor size and stator slot height of a flat wire motor based on electromagnetic-thermal coupling analysis according to claim 1, characterized in that: In step (4), the calculation formula of the electromagnetic material parameters of the flat wire motor is as follows: The calculation formula of the conductivity of the stator winding material is: σ(T) = σ0[1 + α(T - T0)] where σ(T) is the conductivity at temperature T, σ0 is the conductivity at the reference temperature, α is the temperature coefficient of the stator winding material, and T0 is the reference temperature; The calculation formula of the remanent magnetic induction intensity is: Br(T) = Br0[1 + α Br (T - T0)] Among them, Br(T) is the remanent magnetic flux density at temperature T, Br0 is the remanent magnetic flux density at the reference temperature, α Br is the temperature coefficient of remanence, and T0 is the reference temperature; The calculation formula of the intrinsic coercive force is: Hc(T) = Hc0[1 + α Hc (T - T0)] Among them, Hc(T) is the intrinsic coercivity of the permanent magnet at temperature T, Hc0 is the intrinsic coercivity of the permanent magnet at the reference temperature, α Hc is the temperature coefficient of the intrinsic coercivity, and T0 is the reference temperature.

6. The optimization method for the conductor size and stator slot height of a flat wire motor based on electromagnetic-thermal coupling analysis according to claim 1, characterized in that: Adopt the response surface method. According to the Latin hypercube sampling design method, record the average torque and AC loss under the parameter combinations of different conductor sizes and stator slot heights, establish the response surface model of the simplified electromagnetic field model of the flat wire motor, and use the genetic algorithm optimization function in Ansys Maxwell software to globally optimize the conductor size and stator slot height of the flat wire motor; where the basic mathematical expression of the response surface model is: where y is the estimated value of the target response, β0, β i , β ii , β ij are all regression coefficients, m is the number of variables, x i represents the i-th variable, x j represents the j-th variable, and ε is the error.

7. An optimization system for the conductor size and stator slot height of a flat wire motor based on electromagnetic-thermal coupling analysis, characterized in that, including a simplified model establishment and initialization unit for establishing a simplified parametric electromagnetic field model and a simplified temperature field model of the flat wire motor and setting the initial temperature; An electromagnetic field simulation unit, which is used to perform electromagnetic field simulation, calculate the AC loss of the stator winding of the flat wire motor, stator iron loss, rotor iron loss and average torque; A temperature field simulation unit, which is used to use the AC loss of the stator winding of the flat wire motor, stator iron loss and rotor iron loss as the heat source input of the simplified temperature field model of the flat wire motor, use a static solver to perform temperature field simulation on the simplified temperature field model of the flat wire motor, and calculate the temperature of the flat wire motor; according to the temperature of the flat wire motor, reset the material properties of the electromagnetic materials of the flat wire motor in the parameterized electromagnetic field simplified model of the flat wire motor; repeat the electromagnetic field simulation and temperature field simulation to make the temperature of the flat wire motor converge; An optimization variable, optimization objective and constraint condition setting unit, which is used to set the stator conductor size and stator slot height of the flat wire motor as optimization variables, determine their optimization intervals, and at the same time set the minimum AC loss of the flat wire motor as the optimization objective and the unchanged average torque as the constraint condition; A scheme optimization unit, which is used to obtain the optimal values of the stator conductor size and stator slot height of the flat wire motor.

8. An electronic device, characterized in that, It includes a memory and a processor, wherein: The memory is used to store a computer program that can run on the processor; The processor is used to execute the steps of the optimization method for the conductor size and stator slot height of the flat wire motor based on electromagnetic-thermal coupling analysis according to any one of claims 1-6 when running the computer program.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions, which are used to execute the steps of the optimization method for the conductor size and stator slot height of the flat wire motor based on electromagnetic-thermal coupling analysis according to any one of claims 1-6 when the computer instructions are called.

10. A computer program product, characterized in that, It includes a computer program or instruction, and when the computer program or instruction is executed by the processor, it realizes the steps of the optimization method for the conductor size and stator slot height of the flat wire motor based on electromagnetic-thermal coupling analysis according to any one of claims 1-6.

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