A method and device for solving the thermal resistance network of a cylindrical linear motor for Stirling

Abstract

The present invention discloses a method and device for solving the thermal resistance network of a cylindrical linear motor for Stirling. The method comprises: obtaining a convection heat dissipation area and a heat conduction path between various components according to the motor structure; fitting a curve showing changes in thermal parameters in the motor with temperature to obtain a first curve set; the thermal parameters include thermal parameters of a fluid in the motor and thermal parameters of various components; obtaining initial thermal parameters based on an initial temperature distribution in the motor in combination with the first curve set; obtaining the conduction thermal resistance of each component according to the initial thermal parameters; obtaining the convection thermal resistance between the surface of each component and the fluid in the motor according to the initial thermal parameters and the convection heat dissipation area; obtaining a motor thermal resistance network according to the conduction thermal resistance, the convection thermal resistance, the convection heat dissipation area and the heat conduction path, and taking into account the loss of heat source components; iteratively solving the motor thermal resistance network, and updating the values ​​of the thermal parameters in the motor thermal resistance network according to the temperature of each node solved each time, until a termination condition is met, thereby obtaining the temperature of each node in the motor thermal resistance network.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a method and device for solving a thermal resistance network of a cylindrical linear motor for Stirling use. Background Art

[0002] Among analytical methods for calculating motor thermal models, the thermal resistance network method (TRM) is widely used for motor temperature rise assessment due to its relatively simple model construction, short computation time, and high efficiency. By abstracting complex physical structures into nodes and thermal resistance paths, the TRM intuitively reflects the primary heat transfer processes, providing a convenient tool for design analysis.

[0003] However, traditional thermal resistance network methods typically treat thermal parameters such as density and thermal conductivity as fixed, ignoring their linear and nonlinear temperature-dependent characteristics. Stirling generators experience dramatic temperature fluctuations, and the thermal parameters of key components such as metal materials, insulation materials, and permanent magnets exhibit significant temperature-dependent characteristics. Traditional thermal resistance network models, which use constant parameter values, are unable to capture these temperature-dependent characteristics of key components within the motor. This results in a deviation between the calculated temperature distribution and the actual temperature under actual motor operating conditions, limiting the accuracy of the predictions and the practical value of the model.

[0004] Therefore, in the face of application scenarios such as Stirling generators that require high temperature prediction accuracy and have obvious material temperature change characteristics, it is urgent to develop a motor temperature rise assessment method that considers the law of material thermal parameters changing with temperature while retaining the advantages of the thermal resistance network method in terms of efficiency and simplicity, so as to solve the technical problem of how to improve the calculation accuracy of the thermal resistance network node temperature while reducing the calculation cost. Summary of the Invention

[0005] The present invention provides a method and device for solving the thermal resistance network of a cylindrical linear motor for Stirling use, which are used to solve the technical problem of how to improve the calculation accuracy of the node temperature of the thermal resistance network while reducing the calculation cost.

[0006] To achieve the above object, the present invention provides a method for solving the thermal resistance network of a cylindrical linear motor for Stirling use, comprising:

[0007] Determining the convection heat dissipation area of ​​the motor and the heat conduction paths between the components based on the motor structure; fitting a curve showing changes in thermal parameters within the motor with temperature to obtain a first curve set; the thermal parameters include thermal parameters of the fluid within the motor and of the components;

[0008] Initial thermal parameters are obtained based on the initial temperature distribution within the motor in combination with the first curve set; conductive thermal resistance of each component is obtained based on the initial thermal parameters; convection thermal resistance between the surface of each component and the fluid within the motor is obtained based on the initial thermal parameters and the convection heat dissipation area; and a motor thermal resistance network is obtained based on the conductive thermal resistance, the convection thermal resistance, the convection heat dissipation area, and the heat conduction path, taking into account losses in heat source components.

[0009] The motor thermal resistance network is solved iteratively, and the values ​​of the thermal parameters in the motor thermal resistance network are updated according to the temperature of each node solved each time until the preset termination condition is met, and the temperature of each node in the motor thermal resistance network is obtained.

[0010] Preferably, obtaining the convection heat dissipation area of ​​the motor and the heat conduction path between the components according to the motor structure includes:

[0011] The structures of the Stirling generator and the cylindrical linear motor are obtained; simplified modeling is performed based on the structures of the Stirling generator and the cylindrical linear motor to obtain a first model.

[0012] According to the first model, the thermal resistance network solution area, heat source components and non-heat source components in the motor are analyzed. Based on the first model, the non-heat source components are modeled using a classical thermal resistance network, and the heat source components are modeled using a T-type thermal resistance network to obtain the second model. The thermal resistance network solution area includes the linear motor, the area between the linear motor and the Stirling generator casing, and the area between the linear motor and the cold end.

[0013] The heat conduction between the components in the motor is analyzed according to the second model to obtain the heat conduction paths between the components.

[0014] Preferably, the simplified modeling includes:

[0015] An initial model is built according to the structures of the Stirling generator and the cylindrical linear motor; the initial model is simplified to obtain a first model.

[0016] The simplification process includes: deleting threaded holes and screws; eliminating the influence of threaded holes and screws on heat transfer; deleting gaps between components that are smaller than the preset value and treating them as direct contact; eliminating heat transfer in the gaps between components; deleting the fillets and chamfers of each component; and processing the surface of each component to be flat and without depressions.

[0017] Preferably, fitting the curve of the thermal parameters of the motor changing with temperature to obtain the first curve set includes:

[0018] Obtain linear and nonlinear temperature variation curves of the thermal parameters of the fluid and each component in the Stirling generator; the thermal parameters of each component include the thermal conductivity of each component, and the thermal parameters of the fluid include the dynamic viscosity and thermal conductivity of the fluid;

[0019] The influence of temperature on thermal parameters is analyzed according to the linear and nonlinear temperature change curves, and the corresponding temperature change curves are fitted to obtain a first curve set.

[0020] Preferably, obtaining the conductive thermal resistance of each component according to the initial thermal parameters; obtaining the convective thermal resistance between the surface of each component and the fluid in the motor according to the initial thermal parameters and the convective heat dissipation area includes:

[0021] The components in the second model are split into three shapes: concentric tubes, rectangles, and trapezoids to obtain the third model.

[0022] The reference temperature node of each component in the third model is set as a body node; the conduction thermal resistance of each component is obtained according to the third model combined with the thermal conductivity of each component in the initial thermal parameters;

[0023] The convection heat dissipation area is divided into a preset number of sub-areas; a fluid node is set for each sub-area, all convection thermal resistances in the sub-area are connected to the fluid node, and the fluid node is used as the reference temperature node of the sub-area; the convection heat dissipation coefficient of each sub-area is obtained based on the dynamic viscosity and thermal conductivity of the fluid in the initial thermal parameters; and the convection thermal resistance between the surface of each component and the fluid in the motor is obtained based on the third model and the convection heat dissipation coefficient of each sub-area.

[0024] The sub-areas include the contact areas between the walls on both sides of the linear motor air gap and the fluid in the air gap, the contact areas between the stator end face and the fluid, the contact areas between the mover end face and the fluid, and the contact areas between the linear motor housing surface and the fluid.

[0025] Preferably, the motor thermal resistance network is obtained based on the conductive thermal resistance, the convective thermal resistance, the convective heat dissipation area, and the heat conduction path and taking into account the loss of the heat source components, including:

[0026] The body nodes of the heat source components are used as heat source nodes to calculate the losses of the heat source components in the motor.

[0027] The heat source component loss is input into the body node of the heat source component; the heat source component loss includes the motor internal winding copper loss, stator iron loss and permanent magnet eddy current loss.

[0028] The corresponding conduction thermal resistance and convection thermal resistance are connected according to the heat conduction path and the convection heat dissipation area to obtain the motor thermal resistance network.

[0029] Preferably, solving the motor thermal resistance network includes:

[0030] The nodes of the motor thermal resistance network include body nodes and surface nodes; body nodes represent the average temperature of the components; body nodes and surface nodes are connected by conduction thermal resistance; in the motor thermal resistance network, any two adjacent nodes are connected by thermal resistance, forming independent heat flow transfer branches; the thermal resistance of all heat flow transfer branches is calculated to obtain a thermal resistance matrix; the elements in the thermal resistance matrix correspond to the thermal resistance value of each node. The motor thermal resistance network is solved according to the first calculation formula, which includes:

[0031] ;

[0032] in, C represents the thermal resistance network heat capacity matrix; T represents the temperature matrix; t Indicates time; G Represents the thermal resistance matrix of the thermal resistance network. The elements in the thermal resistance matrix are G Thermal resistance of each heat flow branch R The reciprocal of P represents the heat source matrix of the thermal resistance network; T n Indicates the n The temperature of each node; C n Indicates the n The heat capacity of each node; n Indicates the total number of thermal resistance network nodes; Indicates the n Node and i The thermal conductivity between nodes is the reciprocal of thermal resistance; P n Indicates the n The loss of a node. When the corresponding component has no loss, the node loss is 0; and The superscript " ” means to find the transpose.

[0033] Preferably, solving the motor thermal resistance network according to the first calculation formula further includes:

[0034] The hot end temperature boundary in the thermal resistance network is replaced by a compensation temperature boundary, which includes the temperature of the fluid in the compression chamber of the Stirling generator.

[0035] Preferably, the motor thermal resistance network is iteratively solved, and the values ​​of the thermal parameters in the motor thermal resistance network are updated according to the temperature of each node solved each time until a preset termination condition is met. The temperature of each node in the motor thermal resistance network is obtained, including:

[0036] Eliminate the transient temperature rise of the Stirling generator and the linear motor, and eliminate the time-varying temperature characteristics caused by the heat capacity; set the heat capacity matrix to zero; solve the motor thermal resistance network according to the first calculation formula to obtain the steady-state temperature of the motor thermal resistance network.

[0037] The density and thermal conductivity of the thermal parameters of each component are updated according to the steady-state temperature combined with the first curve set to obtain real-time thermal parameters; the conduction thermal resistance and convection thermal resistance in the motor thermal resistance network are updated according to the real-time thermal parameters.

[0038] The motor thermal resistance network is iteratively solved according to the first calculation formula. The iterative calculation is terminated after reaching a maximum preset number of iterations or the maximum temperature difference between two iterations is less than a preset threshold, and the temperature of each node in the motor thermal resistance network is obtained.

[0039] The present invention also provides a thermal resistance network solving device for a cylindrical linear motor for Stirling use, which is used in the method of the present invention. The device includes a first module, a second module, a third module and a fourth module.

[0040] The first module is used to obtain the convection heat dissipation area of ​​the motor and the heat conduction path between various components according to the motor structure;

[0041] The second module is used to fit the curve of the thermal parameters in the motor changing with temperature to obtain a first curve set; the thermal parameters include thermal parameters of the fluid and various components in the motor; the initial thermal parameters are obtained based on the initial temperature distribution in the motor and the first curve set;

[0042] The third module is used to obtain the conduction thermal resistance of each component based on the initial thermal parameters; obtain the convection thermal resistance between the surface of each component and the fluid in the motor based on the initial thermal parameters and the convection heat dissipation area; and obtain the motor thermal resistance network based on the conduction thermal resistance, convection thermal resistance, convection heat dissipation area, and heat conduction path, taking into account the loss of heat source components.

[0043] The fourth module is used to iteratively solve the motor thermal resistance network and update the values ​​of the thermal parameters in the motor thermal resistance network according to the temperature of each node solved each time until the preset termination condition is met, thereby obtaining the temperature of each node in the motor thermal resistance network.

[0044] The present invention has the following beneficial effects:

[0045] The thermal resistance network solution method for the cylindrical linear motor for Stirling of the present invention, by establishing the thermal resistance network model of Stirling generator and cylindrical linear motor, fitting the temperature curve of the thermal parameters of the component materials, converting the thermal resistance into a function of temperature, and then updating the thermal resistance of the component by iterative calculation, realizes a more accurate temperature evaluation on the basis of the traditional thermal resistance network. On the basis of the traditional thermal resistance network method, the influence of the material temperature change characteristics on the temperature rise is taken into account, and the material thermal parameters and thermal resistance can be updated in the solution process, avoiding the problem that the result deviates from the actual working condition as the temperature rises when solving the constant material parameters. It not only has the solution speed of the traditional thermal resistance network, but also realizes a more accurate temperature rise evaluation of the Stirling generator and linear motor. By fitting the linear and nonlinear temperature change curves of the material, updating the material thermal parameters and thermal resistance in iterative calculation, avoiding the problem that the temperature prediction deviates from the actual working condition caused by the inability of the traditional thermal resistance network to estimate the parameter temperature change, and combining the hybrid modeling mode of the T-type thermal resistance network and the classical thermal resistance network, different modeling methods are adopted according to whether there is a heat source, which can ensure the accurate temperature rise evaluation of the heat source component and reduce the number of thermal resistance network nodes. The method of the present invention reduces the calculation cost and improves the calculation accuracy of the temperature of the thermal resistance network node.

[0046] The thermal resistance network solving device for the cylindrical linear motor for Stirling use of the present invention is used in the method of the present invention and has the same beneficial effects as the method of the present invention.

[0047] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0049] Figure 1 It is a schematic cross-sectional structural diagram of a moving-magnetic free-piston Stirling generator according to a preferred embodiment of the present invention.

[0050] Figure 2 It is a schematic cross-sectional structural diagram of a moving coil free piston Stirling generator according to a preferred embodiment of the present invention.

[0051] Figure 3 It is a schematic diagram of a method flow of a preferred embodiment of the present invention.

[0052] Figure 4 It is a schematic diagram of modeling of a heat source-free component in a preferred embodiment of the present invention.

[0053] Figure 5 It is a schematic diagram of modeling of a heat source component in a preferred embodiment of the present invention.

[0054] Figure 6 Schematic diagram of the concentric tube area of ​​a preferred embodiment of the present invention.

[0055] Figure 7 Schematic diagram of a rectangular area according to a preferred embodiment of the present invention.

[0056] Figure 8 It is a schematic diagram of the axial modeling of the outer stator of a preferred embodiment of the present invention.

[0057] Figure 9 It is a schematic diagram of circumferential modeling of the outer stator of a preferred embodiment of the present invention.

[0058] Figure 10 Schematic diagram of a trapezoidal region according to a preferred embodiment of the present invention.

[0059] Figure 11 It is a schematic diagram of segmented modeling of the windings of a moving magnet linear motor according to a preferred embodiment of the present invention.

[0060] Figure 12 It is a schematic diagram of the convection heat dissipation area of ​​the moving-magnet Stirling generator in a preferred embodiment of the present invention.

[0061] Figure 13 It is a schematic diagram of the convection heat dissipation area of ​​the moving coil Stirling generator in a preferred embodiment of the present invention.

[0062] Figure 14 Schematic diagram of the overall thermal resistance network model of the moving-magnet Stirling generator according to the preferred embodiment of the present invention.

[0063] Figure 15 Schematic diagram of the overall thermal resistance network model of the moving-coil Stirling generator according to a preferred embodiment of the present invention.

[0064] Figure 16 1 is a schematic diagram of the finite element simulation results of the temperature field of the moving-magnet Stirling generator according to the preferred embodiment of the present invention.

[0065] Figure 17 Schematic diagram of the finite element simulation results of the temperature field of the moving-coil Stirling generator according to the preferred embodiment of the present invention. DETAILED DESCRIPTION

[0066] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered by the claims.

[0067] In the preferred embodiment of the present invention, a moving magnet free piston Stirling generator and a moving coil free piston Stirling generator are used as examples for analysis. The two types of free piston Stirling generators and cylindrical linear motors mentioned above are only some of the preferred embodiments of the present invention.

[0068] See also Figure 1 The moving magnet free piston Stirling generator uses a single-phase dual-stator moving magnet cylindrical linear motor as the power generation component. Figure 1 Among them, A1 is the hot end of the Stirling generator, A2 is the cold end of the Stirling generator, A3 is the gas distribution piston, A4 is the regenerator, A5 is the cylinder, A6 is the wear-resistant lubrication ring, A7 is the cylinder fixing frame, A8 is the power piston, A9 is the moving magnet cylindrical linear motor, A10 is the power piston connecting frame, A11 is the power piston leaf spring, A12 is the gas distribution piston leaf spring gasket, A13 is the gas distribution piston leaf spring, A14 is the voice coil motor fixing ring, A15 is the gas distribution piston rod, A16 is the voice coil motor connecting frame, A17 is the voice coil motor, A18 is the Stirling generator casing, and A19 is the Stirling generator base. In the moving magnet cylindrical linear motor, A91 is the inner and outer stator connecting frame, A92 is the outer stator of the motor, A93 is the motor winding, A94 is the motor casing, A95 is the inner stator of the motor, A96 is the permanent magnet of the motor, and A97 is the motor mover.

[0069] See also Figure 2 The moving coil free piston Stirling generator uses a single-phase dual permanent magnet moving coil cylindrical linear motor as the power generation component. Figure 2 In the figure, B1 is the hot end of the Stirling generator, B2 is the cold end of the Stirling generator, B3 is the valve piston, B4 is the regenerator, B5 is the cylinder, B6 is the 7-pin terminal, B7 is the power piston, B8 is the 1-pin terminal, B9 is the moving coil cylindrical linear motor, B10 is the power piston connector, B11 is the cylinder connector, B12 is the counterweight copper ring, B13 is the power piston leaf spring connector, B14 is the power piston leaf spring, B15 is the displacement sensor, B16 is the valve piston leaf spring washer, B17 is the valve piston leaf spring, B18 is the valve piston rod, B19 is the Stirling generator housing, and B20 is the Stirling generator base. In the moving coil cylindrical linear motor, B91 is the moving coil motor U-shaped stator, B92 is the permanent magnet connector, B93 is the permanent magnet, B94 is the motor winding, and B95 is the motor mover.

[0070] See also Figure 3 In a preferred embodiment of the present invention, a method for solving the thermal resistance network of a Stirling cylindrical linear motor is provided, comprising:

[0071] S1. Determine the convection heat dissipation area of ​​the motor and the heat conduction path between the components based on the motor structure. S1 specifically includes:

[0072] Obtain the structures of the Stirling generator and cylindrical linear motor; simplify modeling based on these structures to obtain the first model. Analyze the first model to determine the thermal resistance network solution region within the motor, as well as components with and without heat sources. Based on the first model, a classic thermal resistance network is used to model components without heat sources, and a T-type thermal resistance network is used to model components with heat sources, resulting in the second model. The thermal resistance network solution region includes the linear motor, the region between the linear motor and the Stirling generator housing, and the region between the linear motor and the cold end. The second model analyzes heat conduction between the motor components to determine the heat conduction paths between them.

[0073] In a preferred embodiment of the present invention, simplified modeling includes:

[0074] An initial model was constructed based on the structure of the Stirling generator and the cylindrical linear motor; the initial model was simplified to obtain the first model; the simplification process included: deleting threaded holes and screws; eliminating the influence of threaded holes and screws on heat transfer; deleting gaps between components that were less than a preset value and regarded them as direct contact; eliminating heat transfer through gaps between components; deleting fillets and chamfers of each component; and treating the surface of each component to be flat and free of depressions.

[0075] In the preferred embodiment of the present invention, see Figure 4 For components without heat sources, their temperature distribution is generally not of concern, and a classic thermal resistance network is used for modeling to achieve the purpose of reducing the overall network nodes. P and heat capacity C The temperature of the body node represents the average temperature of the component and is connected to the surface node through the conduction thermal resistance. The conduction thermal resistance is used to calculate the heat transfer inside each solid component or between solid components. Figure 4 middle, R x1 、 R x2 is the radial thermal resistance, R y1 、 R y2 is the circumferential thermal resistance, R z1 、 R z2 is the axial thermal resistance.

[0076] In the preferred embodiment of the present invention, see Figure 5 For heat source components, the temperature calculation determines the accuracy of the overall calculation results, and a more complex but accurate T-type thermal resistance network is required for modeling. This network adds a negative compensation thermal resistance to the classic thermal resistance network used for components without heat sources. Figure 5 middle,R x3 、 R y3 、 R z3 To compensate for the increased thermal resistance.

[0077] exist Figures 4 and 5 middle, T 1 to T 6 represents the node temperature. In the thermal resistance network modeling of the preferred embodiment of the present invention, the thermal resistance in the orange rectangle represents the conduction thermal resistance, and the thermal resistance in the white rectangle represents the compensation thermal resistance.

[0078] In a preferred embodiment of the present invention, the calculation area for the moving magnet motor is A2, A5, A6, A7, A8, A9, A11, A18, and the helium areas between these components. For the moving magnet linear motor, A92, A93, A95, and A96 are heat sources, and the remaining components are considered to be heat-free. For the moving coil motor, the calculation area is B2, B5, B7, B9, B10, B11, B12, B13, B14, and B19, and the helium areas between these components. For the moving coil linear motor, B91, B93, and B94 are heat sources, and the remaining components are considered to be heat-free.

[0079] S2. Fitting a curve showing changes in thermal parameters within the motor with temperature to obtain a first curve set; the thermal parameters include thermal parameters of the fluid and components within the motor; and obtaining initial thermal parameters based on an initial temperature distribution within the motor in combination with the first curve set.

[0080] In a preferred embodiment of the present invention, the curve of the thermal parameters of the motor changing with temperature is fitted to obtain the first curve set including:

[0081] Obtain linear and nonlinear temperature variation curves of the thermal parameters of the fluid and each component in the Stirling generator; the thermal parameters of each component include the thermal conductivity of each component, and the thermal parameters of the fluid include the dynamic viscosity and thermal conductivity of the fluid;

[0082] The influence of temperature on thermal parameters is analyzed according to the linear and nonlinear temperature change curves, and the corresponding temperature change curves are fitted to obtain a first curve set.

[0083] In a preferred embodiment of the present invention, the thermal conductivity of each component within the Stirling generator, as well as the dynamic viscosity and thermal conductivity of the fluid, varies with temperature. As the motor temperature increases, the thermal resistance of the corresponding components and fluid also changes. This results in a thermal resistance network calculated with a constant thermal resistance, resulting in node temperatures that do not match the actual motor operating temperature. Therefore, the present invention converts the previously constant thermal resistance into a dynamic thermal resistance that varies with temperature by fitting the temperature-dependent curves of the thermal conductivity of each component and the dynamic viscosity and thermal conductivity of the fluid.

[0084] In a preferred embodiment of the present invention, different parameters are used to dynamically update the conductive thermal resistance and the convective thermal resistance. For the conductive thermal resistance, the change of the thermal conductivity of the material with temperature is taken into account; for the convective thermal resistance, the change of the dynamic viscosity and thermal conductivity with temperature is taken into account.

[0085] In a preferred embodiment of the present invention, the fitting curve of the dynamic viscosity of the fluid with temperature includes:

[0086] ;

[0087] in, Indicates the dynamic viscosity of the fluid. The fluid inside the Stirling generator is 2Mpa helium.

[0088] In the embodiment of the present invention, the residual thermal parameter fitting curve formulas of the materials and fluids of the two types of Stirling generator components are shown in Table 1. Since the embodiment only considers the steady-state temperature rise, the material specific heat capacity is not listed in the table, where T Indicates the temperature of the reference temperature node in units of K The density of the fluid (helium) is used in the subsequent calculation of the convection heat dissipation coefficient.

[0089] Table 1 Thermal parameters of materials of various components inside the Stirling generator

[0090] ;

[0091] S3. Obtain the conduction thermal resistance of each component based on the initial thermal parameters; obtain the convection thermal resistance between the surface of each component and the fluid in the motor based on the initial thermal parameters and the convection heat dissipation area. S3 specifically includes:

[0092] The components in the second model are split into three shapes: concentric tubes, rectangles, and trapezoids to obtain the third model.

[0093] The reference temperature node of each component in the third model is set as a body node; and the conduction thermal resistance of each component is obtained according to the third model combined with the thermal conductivity of each component in the initial thermal parameters.

[0094] The convection heat dissipation area is divided into a preset number of sub-areas; a fluid node is set for each sub-area, all convection thermal resistances in the sub-area are connected to the fluid node, and the fluid node is used as the reference temperature node of the sub-area; the convection heat dissipation coefficient of each sub-area is obtained based on the dynamic viscosity and thermal conductivity of the fluid in the initial thermal parameters; and the convection thermal resistance between the surface of each component and the fluid in the motor is obtained based on the third model and the convection heat dissipation coefficient of each sub-area.

[0095] The sub-areas include the contact areas between the walls on both sides of the linear motor air gap and the fluid in the air gap, the contact areas between the stator end face and the fluid, the contact areas between the mover end face and the fluid, and the contact areas between the linear motor housing surface and the fluid.

[0096] In conventional thermal resistance network methods, fluid temperature is often used as a constant value to characterize convective heat dissipation. Fluid temperature acts as a fixed temperature source in the thermal network, to which convective thermal resistances are connected. Clearly, conventional thermal resistance network methods fail to account for differences in convective heat dissipation caused by differences in fluid temperature across different regions. Therefore, in a preferred embodiment of the present invention, the heat dissipation region is divided into subregions, and a fluid node is assigned to each subregion to characterize the average fluid temperature of each subregion. All convective thermal resistances within the same region are connected to this node, with this node serving as the reference temperature node for the subregion.

[0097] In a preferred embodiment of the present invention, since both the Stirling generator and the linear motor are symmetrical structures, the shapes of the components in the thermal resistance network solution area can be simplified and equivalent, being considered as a combination of concentric circular tubes, rectangles, and trapezoids. This reduces the complex component heat transfer problem to the heat transfer of simple shapes. For components of different shapes, only the thermal conductivity of the material used is considered, and the corresponding calculation formula is used to calculate the conduction thermal resistance, specifically including:

[0098] (1) Concentric tube area

[0099] See also Figure 6 The concentric tube area is axially symmetrical as a whole, and its circumferential heat transfer can be ignored. Only the radial and axial heat transfer are considered, and its conduction thermal resistance includes:

[0100] ;

[0101] ;

[0102] ;

[0103] in, 、 is the radial thermal resistance, is the radial compensation thermal resistance, 、 is the circumferential thermal resistance, is the circumferential compensation thermal resistance, 、 is the axial thermal resistance, is the axial compensation thermal resistance. is the circumferential angle. For the concentric tube area, its value is taken as 2p, and the circumferential thermal resistance is ignored. is the thermal conductivity in the corresponding direction. It is the inner and outer diameters and circumferential length of the circular tube.

[0104] In an embodiment of the present invention, the moving magnet linear motors A91, A93, A94, A95, A96, and A97, the moving coil Stirling generators B91, B92, B93, B94, and B95, and the corresponding components of the Stirling generators can all be regarded as concentric circular tube areas.

[0105] (2) Rectangular area

[0106] See also Figure 7 For Stirling generators, irregular components are usually divided into multiple rectangular areas, and then the conduction thermal resistance in each rectangular area is calculated separately. Finally, the thermal resistances are connected to form a thermal resistance network of the irregular component. In an embodiment of the present invention, the outer stator of the dynamic magnet linear motor is regarded as a plurality of rectangular areas spliced ​​together. Since a certain amount of iron loss will be generated in the outer stator during the movement, a T-type thermal resistance network can be used for modeling in each rectangular area. At the same time, considering that the outer stator is evenly distributed along the circumference, the temperature distribution of each stator must be the same. All the outer stator thermal resistances can be connected in parallel, that is, the transferred heat flow is calculated using the thermal resistance of a single stator, and the thermal resistance in each direction is 1 / 12 of the original. For modeling of the outer stator of the dynamic magnet linear motor, see Figures 8 and 9 .in, Figure 8 This is a schematic diagram of the axial modeling of the outer stator. Figure 9 This is a schematic diagram of the circumferential modeling of the outer stator. The conduction thermal resistance in the rectangular area includes:

[0107] ;

[0108] in, is the heat flow conduction length, is the thermal resistance along the direction of heat flow conduction, is the compensation thermal resistance along the direction of heat flow conduction; is the area perpendicular to the heat flow conduction direction. It should be noted that the outer stator is stacked along the circumferential direction, and the corresponding Directional thermal conductivity varies.

[0109] (3) Trapezoidal area

[0110] See also Figure 10For Stirling generators, the radial heat transfer paths and loss values ​​of some annular components are different, resulting in uneven circumferential temperature distribution. For these components, they are usually divided into multiple trapezoidal areas, the conduction thermal resistance in each area is calculated, and then the components are connected one by one through the circumferential thermal resistance, and finally a thermal resistance network of the annular area is formed. In an embodiment of the present invention, the heat transfer paths of the inner winding of the outer stator of the dynamic magnet Stirling generator and the winding between the outer stators are significantly different. The winding between the outer stators is divided into trapezoidal areas, and the inner winding of the outer stator can be regarded as a rectangular area for calculation. The obtained thermal resistances of each part are connected along the circumference, and are also connected in parallel in the same way as the outer stator of the rectangular area. For the segmented modeling of the winding of the dynamic magnet linear motor, see. Figure 11 The conduction thermal resistance of the trapezoidal area includes:

[0111] ;

[0112] ;

[0113] ;

[0114] in, and is the upper and lower side lengths and height of the trapezoid.

[0115] In a preferred embodiment of the present invention, the convection heat dissipation coefficient is calculated as follows:

[0116] ;

[0117] ;

[0118] ;

[0119] in, is the Reynolds number; is the fluid density, which is 2 MPa helium density in the Stirling generator; is the average velocity of the fluid flow; is the characteristic length at the calculation position; is the fluid dynamic viscosity; is the Grashof number; is the Prandtl number; is the Nusselt number, and the Reynolds number , Grashov number and Prandtl number Combined with the empirical formula to solve the problem; is the thermal conductivity of the fluid; is the fluid convection heat dissipation coefficient.

[0120] Convection thermal resistance includes:

[0121] ;

[0122] in, is the convection thermal resistance; is the area of ​​each convection heat dissipation contact surface; is the convection heat dissipation coefficient.

[0123] S4. Calculate the motor thermal resistance network based on the conduction thermal resistance, convection thermal resistance, convection heat dissipation area, and heat conduction path, taking into account the loss of heat source components. S4 specifically includes:

[0124] The body nodes of the heat source components are used as heat source nodes to calculate the losses of the heat source components in the motor.

[0125] The heat source component loss is input into the body node of the heat source component; the heat source component loss includes the motor internal winding copper loss, stator iron loss and permanent magnet eddy current loss.

[0126] The corresponding conduction thermal resistance and convection thermal resistance are connected according to the heat conduction path and the convection heat dissipation area to obtain the motor thermal resistance network.

[0127] In a preferred embodiment of the present invention, the interior of the Stirling generator is filled with 2Mpa helium. As the linear motor rotor moves, convection heat dissipation continuously occurs on the contact surface between the linear motor and the fluid. For the interior of the Stirling generator, the convection thermal resistance of the linear motor air gap, stator end face, rotor moving surface, and linear motor housing is calculated. For the exterior of the Stirling generator, only the natural convection heat dissipation between the Stirling generator housing and the outside world is considered. In the embodiment of the present invention, the convection calculation area of ​​the two types of motors is shown in FIG. Figures 12 to 13 ,in Figure 12 This is the convection heat dissipation area of ​​the moving magnet Stirling generator. Figure 13 It is the convection heat dissipation area of ​​the moving coil Stirling generator.

[0128] For the convection calculation area inside the Stirling generator, each contact surface transfers heat to the preset fluid node through the convection thermal resistance. Assuming that the air gap temperature is equal everywhere, the internal flow velocity distribution of the Stirling generator is calculated by CFD simulation software, and the convection heat dissipation coefficient of each area of ​​the two types of motors is obtained by combining the convection heat dissipation coefficient calculation formula, see Table 2 and Table 3. For the external area of ​​the Stirling generator, it is regarded as natural convection heat dissipation, and the convection heat dissipation coefficient is set to 15W / m 2 ℃, the external environment temperature is 22℃.

[0129] Table 2 Calculation results of convection heat dissipation coefficient of moving-magnet Stirling generator

[0130] ;

[0131] Table 3 Calculation results of convection heat dissipation coefficient of moving coil Stirling generator

[0132] ;

[0133] In the embodiment of the present invention, the thermal resistance network models of the two types of Stirling generators and linear motors are shown in Figures 14 and 15 See also Figure 14 For the moving-magnet Stirling generator and linear motor, the network has a total of 128 nodes, of which nodes 16, 19, 24, and 27 are inner stator nodes, nodes 37, 44, 50, and 56 are permanent magnet nodes, nodes 87, 94, 98, 112, 115, and 119 are outer stator nodes, nodes 105, 108, and 127 are winding nodes, and nodes 1, 63, 66, and 124 are temperature nodes, corresponding to temperatures of 55°C, 30°C, 22°C, and 22°C. Figure 15 ,For the moving-coil Stirling generator and linear motor, the network has a total of 164 nodes, of which nodes 40, 44, 47, 50, 84, 87, 96, 99, 106, and 109 are U-shaped stator nodes, nodes 56, 63, 68, and 71 are winding nodes, nodes 90, 93, 102, and 112 are permanent magnet nodes, and the temperatures of the temperature nodes 1, 128, and 164 are 55°C, 22°C, and 30°C, respectively.

[0134] In a preferred embodiment of the present invention, two types of linear motor two-dimensional models are built using the electromagnetic field simulation software ANSYS Electronics Desktop 2022R1 to calculate the winding copper loss, stator iron loss, and permanent magnet eddy current loss. The values ​​are shown in Table 4.

[0135] Table 4 Loss values ​​and nodes of each component of Stirling generator

[0136] ;

[0137] S5. Iteratively solve the motor thermal resistance network and update the values ​​of thermal parameters in the motor thermal resistance network according to the temperature of each node solved each time until the preset termination condition is met, thereby obtaining the temperature of each node in the motor thermal resistance network.

[0138] In a preferred embodiment of the present invention, solving the motor thermal resistance network includes:

[0139] The motor thermal resistance network includes body nodes and surface nodes; body nodes represent the average temperature of the components; body nodes and surface nodes are connected by conduction thermal resistance; in the motor thermal resistance network, any two adjacent nodes are connected to each other through thermal resistance, forming independent heat flow transfer branches; the thermal resistance of all heat flow transfer branches is calculated to obtain a thermal resistance matrix; the elements in the thermal resistance matrix correspond to the thermal resistance value of each node.

[0140] Solve the motor thermal resistance network according to the first calculation formula, which includes:

[0141] ;

[0142] in, C represents the thermal resistance network heat capacity matrix; T represents the temperature matrix; t Indicates time; G Represents the thermal resistance matrix of the thermal resistance network. The elements in the thermal resistance matrix are G Thermal resistance of each heat flow branch R The reciprocal of P represents the heat source matrix of the thermal resistance network; T n Indicates the n The temperature of each node; C n Indicates the n The heat capacity of each node; n Indicates the total number of thermal resistance network nodes; Indicates the n Node and i The thermal conductivity between nodes is the reciprocal of thermal resistance; P n Indicates the n The loss of a node. When the corresponding component has no loss, the node loss is 0; and The superscript " ” means to find the transpose.

[0143] In a preferred embodiment of the present invention, when solving the motor thermal resistance network according to the first calculation formula, Indicates the temperature of any node in the thermal resistance network, i.e. the quantity to be solved. In actual solution, the temperature of some nodes can be determined in advance by measurement or assumption. These nodes are called the temperature boundary of the thermal resistance network and will affect the final solution result. m Corresponding temperature T m When the matrix is ​​known, the matrix T and P middle m Set the row elements to zero and transform the matrix C and matrix G middle m Line and m Set the column elements to zero and then add the diagonal elements of the two matrices C m and Set it to 1, and then calculate the temperature of the remaining nodes according to the first calculation formula.

[0144] In a preferred embodiment of the present invention, the temperature boundaries of the thermal resistance network include the ambient temperature, the cold end, and the compensation temperature boundary. These temperature boundaries are added to the thermal resistance network in the form of temperature sources. The ambient temperature is 22°C and the cold end temperature is 30°C. In order to further improve the accuracy of the thermal resistance network, the present invention proposes a compensation temperature boundary in the thermal network to replace the hot end temperature as the temperature boundary, and uses the actual measured fluid temperature in the compression chamber of the Stirling generator as the temperature value of the compensation temperature boundary to reduce the prediction error between the thermal resistance network and the actual motor operating temperature. In an embodiment of the present invention, the temperature value of the compensation temperature boundary is 55°C.

[0145] In a preferred embodiment of the present invention, S5 specifically includes:

[0146] Eliminate the transient temperature rise of the Stirling generator and the linear motor, and eliminate the time-varying temperature characteristics caused by the heat capacity; set the heat capacity matrix to zero; solve the motor thermal resistance network according to the first calculation formula to obtain the steady-state temperature of the motor thermal resistance network.

[0147] The density and thermal conductivity of the thermal parameters of each component are updated according to the steady-state temperature combined with the first curve set to obtain real-time thermal parameters; the conduction thermal resistance and convection thermal resistance in the motor thermal resistance network are updated according to the real-time thermal parameters.

[0148] In a preferred embodiment of the present invention, the specific heat capacity is regarded as 0 during the thermal network solution process.

[0149] The motor thermal resistance network is iteratively solved according to the first calculation formula. The iterative calculation is terminated after reaching a maximum preset number of iterations or the maximum temperature difference between two iterations is less than a preset threshold, and the temperature of each node in the motor thermal resistance network is obtained.

[0150] The thermal resistance network solution method for the cylindrical linear motor for Stirling of the present invention, by establishing the thermal resistance network model of Stirling generator and cylindrical linear motor, fitting the temperature curve of the thermal parameters of the component materials, converting the thermal resistance into a function of temperature, and then updating the thermal resistance of the component by iterative calculation, realizes a more accurate temperature evaluation on the basis of the traditional thermal resistance network. On the basis of the traditional thermal resistance network method, the influence of the material temperature change characteristics on the temperature rise is taken into account, and the material thermal parameters and thermal resistance can be updated in the solution process, avoiding the problem that the result deviates from the actual working condition as the temperature rises when solving the constant material parameters. It not only has the solution speed of the traditional thermal resistance network, but also realizes a more accurate temperature rise evaluation of the Stirling generator and linear motor. By fitting the linear and nonlinear temperature change curves of the material, updating the material thermal parameters and thermal resistance in iterative calculation, avoiding the problem that the temperature prediction deviates from the actual working condition caused by the inability of the traditional thermal resistance network to estimate the parameter temperature change, and combining the hybrid modeling mode of the T-type thermal resistance network and the classical thermal resistance network, different modeling methods are adopted according to whether there is a heat source, which can ensure the accurate temperature rise evaluation of the heat source component and reduce the number of thermal resistance network nodes. The method of the present invention reduces the calculation cost and improves the calculation accuracy of the temperature of the thermal resistance network node.

[0151] In a preferred embodiment of the present invention, a thermal resistance network solving device for a cylindrical linear motor for Stirling is also provided, which is used in the method of the present invention. The device includes a first module, a second module, a third module and a fourth module.

[0152] The first module is used to obtain the convection heat dissipation area of ​​the motor and the heat conduction path between various components according to the motor structure;

[0153] The second module is used to fit the curve of the thermal parameters in the motor changing with temperature to obtain a first curve set; the thermal parameters include thermal parameters of the fluid and various components in the motor; the initial thermal parameters are obtained based on the initial temperature distribution in the motor and the first curve set;

[0154] The third module is used to obtain the conduction thermal resistance of each component based on the initial thermal parameters; obtain the convection thermal resistance between the surface of each component and the fluid in the motor based on the initial thermal parameters and the convection heat dissipation area; and obtain the motor thermal resistance network based on the conduction thermal resistance, convection thermal resistance, convection heat dissipation area, and heat conduction path, taking into account the loss of heat source components.

[0155] The fourth module is used to iteratively solve the motor thermal resistance network and update the values ​​of the thermal parameters in the motor thermal resistance network according to the temperature of each node solved each time until the preset termination condition is met, thereby obtaining the temperature of each node in the motor thermal resistance network.

[0156] The thermal resistance network solving device for the cylindrical linear motor for Stirling use of the present invention is used in the method of the present invention and has the same beneficial effects as the method of the present invention.

[0157] Verification part:

[0158] In the embodiment of the present invention, the maximum number of iterations is set to 20 times, the threshold is set to 1°C, and the node temperature of the thermal resistance network is obtained through iterative calculation. In order to further illustrate the advantages of the present invention, the thermal resistance network results obtained by the method of the present invention are compared with conventional methods and simulations. The conventional method does not consider the changes in the thermal parameters of the component material with temperature, and the thermal resistance network is not updated during the solution process, which is equivalent to the node temperature obtained by the method of the present invention only performing one calculation. At the same time, in order to prove the correctness of the method of the present invention, the obtained component node temperature is compared with the motor temperature obtained by finite element simulation. The simulated temperatures of the two types of Stirling generators and linear motors are shown in Fig. Figures 16 and 17 ,in, Figure 16 is the finite element simulation result of the temperature field of the moving magnet Stirling generator, Figure 17 The finite element simulation results for the temperature field of a moving-coil Stirling generator are shown in Tables 5 and 6. The node temperatures of some nodes in the thermal resistance network are compared.

[0159] As can be seen from the table, after using the method of the present invention, the temperature results of each node are closer to the simulation values. The maximum errors for the moving magnet motor and the moving coil motor are 2.3°C and 2.4°C, respectively, which are significantly improved compared to the accuracy of conventional methods. Among them, node 108 in Table 5 and nodes 56 and 68 in Table 6 are all winding nodes. Among all electromagnetic heat source components, the copper loss value of the winding is the highest, causing its temperature to be higher than that of other components. In the components in the surrounding area, the heat generated by the winding is continuously transferred to these components, resulting in a rapid temperature rise even though the loss value is relatively small, causing significant changes in the thermal parameters of the material. Conventional methods cannot describe this material temperature change characteristic, and the final values ​​obtained are significantly different from the simulation. As can be seen in the table, the maximum temperature difference between the conventional method and the simulation results can reach 8.08°C, which is clearly inconsistent with the actual operating conditions. These results show that the thermal resistance network proposed by the present invention, which takes into account the temperature change characteristics of the material, improves the accuracy of temperature rise assessment compared to traditional thermal resistance networks and can better reflect the temperature rise of the motor during actual operation.

[0160] Table 5 Comparison of thermal resistance network temperature of moving-magnet Stirling generator

[0161] ;

[0162] Table 6 Comparison of thermal resistance network temperature of moving coil Stirling generator

[0163] ;

[0164] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for solving the thermal resistance network of a Stirling cylindrical linear motor, characterized in that: include: Determining the convection heat dissipation area of ​​the motor and the heat conduction paths between the components based on the motor structure; fitting a curve showing changes in thermal parameters within the motor with temperature to obtain a first curve set; the thermal parameters include thermal parameters of the fluid within the motor and of the components; Initial thermal parameters are obtained based on the initial temperature distribution within the motor in combination with the first curve set; conductive thermal resistance of each component is obtained based on the initial thermal parameters; convection thermal resistance between the surface of each component and the fluid within the motor is obtained based on the initial thermal parameters and the convection heat dissipation area; and a motor thermal resistance network is obtained based on the conductive thermal resistance, the convection thermal resistance, the convection heat dissipation area, and the heat conduction path, taking into account losses in heat source components. Iteratively solving the motor thermal resistance network and updating the values ​​of thermal parameters in the motor thermal resistance network according to the temperature of each node solved each time until a preset termination condition is met, thereby obtaining the temperature of each node in the motor thermal resistance network; The method of obtaining the convection heat dissipation area of ​​the motor and the heat conduction paths between the components according to the motor structure includes: Obtaining the structures of the Stirling generator and the cylindrical linear motor; performing simplified modeling based on the structures of the Stirling generator and the cylindrical linear motor to obtain a first model; An analysis is performed based on the first model to obtain a thermal resistance network solution region, components with heat sources, and components without heat sources within the motor; based on the first model, a classical thermal resistance network is used to model the components without heat sources, and a T-type thermal resistance network is used to model the components with heat sources, thereby obtaining a second model; the thermal resistance network solution region includes the linear motor, the region between the linear motor and the Stirling generator housing, and the region between the linear motor and the cold end; The heat conduction conditions between the components in the motor are analyzed according to the second model to obtain the heat conduction paths between the components.

2. The method for solving the thermal resistance network of a cylindrical linear motor for Stirling use according to claim 1, characterized in that: The simplified modeling includes: Building an initial model based on the structures of the Stirling generator and the cylindrical linear motor; simplifying the initial model to obtain the first model; The simplification process includes: deleting threaded holes and screws; eliminating the influence of threaded holes and screws on heat transfer; deleting gaps between components that are smaller than a preset value and treating them as direct contact; eliminating heat transfer in the gaps between components; deleting fillets and chamfers of each component; and processing the surface of each component to be flat and free of depressions.

3. The method for solving the thermal resistance network of a cylindrical linear motor for Stirling use according to claim 2, characterized in that: The first curve set obtained by fitting the curve of the thermal parameters of the motor changing with temperature includes: Obtaining linear and nonlinear temperature variation curves of thermal parameters of the fluid and each component in the Stirling generator; the thermal parameters of each component include the thermal conductivity of each component, and the thermal parameters of the fluid include the dynamic viscosity and thermal conductivity of the fluid; The influence of temperature on the thermal parameters is analyzed according to the linear and nonlinear temperature change curves, and the corresponding temperature change curves are fitted to obtain the first curve set.

4. The method for solving the thermal resistance network of a cylindrical linear motor for Stirling use according to claim 3, characterized in that: Obtaining the conduction thermal resistance of each component according to the initial thermal parameters; The convective thermal resistance between the surface of each component and the fluid in the motor is obtained according to the initial thermal parameters and the convective heat dissipation area, including: The components in the second model are split into three shapes: concentric tubes, rectangles, and trapezoids to obtain a third model; Setting the reference temperature node of each component in the third model as a body node; obtaining the conduction thermal resistance of each component according to the third model combined with the thermal conductivity of each component in the initial thermal parameters; The convection heat dissipation area is divided into a preset number of sub-areas; a fluid node is set for each sub-area, all convection thermal resistances in the sub-area are connected to the fluid node, and the fluid node is used as a reference temperature node for the sub-area; the convection heat dissipation coefficient of each sub-area is obtained based on the dynamic viscosity and thermal conductivity of the fluid in the initial thermal parameters; and the convection thermal resistance between the surface of each component and the fluid in the motor is obtained based on the third model and the convection heat dissipation coefficient of each sub-area; The sub-areas include the contact areas between the walls on both sides of the linear motor air gap and the fluid in the air gap, the contact areas between the stator end face and the fluid, the contact areas between the mover end face and the fluid, and the contact areas between the linear motor housing surface and the fluid.

5. The method for solving the thermal resistance network of a cylindrical linear motor for Stirling use according to claim 4, characterized in that: The motor thermal resistance network is obtained based on the conductive thermal resistance, the convection thermal resistance, the convection heat dissipation area, and the heat conduction path, and taking into account the loss of heat source components. The network includes: The body nodes of the heat source components are used as heat source nodes to calculate the losses of the heat source components in the motor; Inputting the heat source component loss into the body node of the heat source component; the heat source component loss includes the motor internal winding copper loss, stator iron loss and permanent magnet eddy current loss; The corresponding conductive thermal resistance and convection thermal resistance are connected according to the heat conduction path and the convection heat dissipation area to obtain the motor thermal resistance network.

6. The method for solving the thermal resistance network of a cylindrical linear motor for Stirling use according to claim 5, characterized in that: Solving the motor thermal resistance network includes: The nodes of the motor thermal resistance network include body nodes and surface nodes; the motor thermal resistance network is solved according to a first calculation formula, and the first calculation formula includes: ； in, represents the thermal resistance network heat capacity matrix; represents the temperature matrix; Indicates time; Represents the thermal resistance matrix of the thermal resistance network. The elements in the thermal resistance matrix are Thermal resistance of each heat flow branch The reciprocal of represents the heat source matrix of the thermal resistance network; Indicates the The temperature of each node; Indicates the The heat capacity of each node; Indicates the total number of thermal resistance network nodes; Indicates the Node and The thermal conductivity between nodes is the reciprocal of thermal resistance; Indicates the The loss of a node. When the corresponding component has no loss, the node loss is 0; and The superscript " ” means to find the transpose.

7. The method for solving the thermal resistance network of a cylindrical linear motor for Stirling use according to claim 6, characterized in that: Solving the motor thermal resistance network according to the first calculation formula also includes: The hot end temperature boundary in the thermal resistance network is replaced by a compensation temperature boundary, wherein the compensation temperature boundary includes the temperature of the fluid in the compression chamber of the Stirling generator.

8. The method for solving the thermal resistance network of a cylindrical linear motor for Stirling use according to claim 7, characterized in that: Iteratively solving the motor thermal resistance network and updating the values ​​of thermal parameters in the motor thermal resistance network according to the temperature of each node solved each time until a preset termination condition is met. The temperature of each node in the motor thermal resistance network is obtained, including: Eliminating the transient temperature rise of the Stirling generator and the linear motor, and eliminating the time-varying temperature characteristics caused by the heat capacity; setting the heat capacity matrix to zero; solving the motor thermal resistance network according to the first calculation formula to obtain the steady-state temperature of the motor thermal resistance network; updating the density and thermal conductivity of the thermal parameters of each component according to the steady-state temperature in combination with the first curve set to obtain real-time thermal parameters; updating the conduction thermal resistance and convection thermal resistance in the motor thermal resistance network according to the real-time thermal parameters; The motor thermal resistance network is iteratively solved according to the first calculation formula, and the iterative calculation is terminated after a maximum preset number of iterations is reached or the maximum temperature difference between two iterations is less than a preset threshold to obtain the temperature of each node in the motor thermal resistance network.

9. A thermal resistance network solving device for a cylindrical linear motor for Stirling use, used in the method according to any one of claims 1 to 8, characterized in that: The device includes a first module, a second module, a third module and a fourth module; The first module is used to obtain the convection heat dissipation area of ​​the motor and the heat conduction path between various components according to the motor structure; The second module is used to fit the curve of the thermal parameters in the motor changing with temperature to obtain a first curve set; the thermal parameters include thermal parameters of the fluid and various components in the motor; the initial thermal parameters are obtained based on the initial temperature distribution in the motor and the first curve set; The third module is used to obtain the conductive thermal resistance of each component based on the initial thermal parameters; obtain the convective thermal resistance between the surface of each component and the fluid in the motor based on the initial thermal parameters and the convective heat dissipation area; and obtain the motor thermal resistance network based on the conductive thermal resistance, the convective thermal resistance, the convective heat dissipation area, and the heat conduction path, taking into account the loss of the heat source component; The fourth module is used to iteratively solve the motor thermal resistance network and update the values ​​of thermal parameters in the motor thermal resistance network according to the temperature of each node solved each time until a preset termination condition is met, thereby obtaining the temperature of each node in the motor thermal resistance network.

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