Method for calculating temperature rise of permanent magnet and conductor cylinder of eddy current damper based on electromagnetic-temperature field coupling

Abstract

The invention discloses a method for calculating temperature rise of a permanent magnet and a conductor cylinder of an eddy current damper based on electromagnetic-temperature field coupling. The method comprises the following steps: firstly, building an equivalent magnetic circuit model for an electromagnetic field of the eddy current damper; secondly, the running speed of the permanent magnet and the temperature of the conductor cylinder and the permanent magnet are associated with eddy-current loss in a multivariate mapping mode and serve as a heat source input basis of a temperature field; and finally, constructing an equivalent thermal network model of a temperature field, and calculating the temperature rise of the permanent magnet and the conductor cylinder. On the basis of an equivalent magnetic circuit method and an equivalent thermal network method, a calculation method considering temperature rise of a permanent magnet and a conductor cylinder of the eddy current damper under electromagnetic-temperature field coupling is provided, and eddy current loss in the conductor cylinder under different working conditions is corrected in a multivariate mapping mode; and a theoretical tool is provided for accurately predicting the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper and heat management.

Description

Technical Field

[0001] The present invention relates to the field of electromagnetic - temperature field coupling of eddy current dampers, and particularly to a calculation method for the temperature rise of permanent magnets and conductor cylinders of an eddy current damper based on electromagnetic - temperature field coupling. Background Art

[0002] With the wide application of electromagnetic braking technology, eddy current dampers, with their advantages of non - contact braking and fast dynamic response, are often used in engineering fields such as vehicle braking, vibration suppression, space docking, and transmission systems. However, in the design trend towards miniaturization, low cost, and high braking force, a series of heat - related problems caused by temperature rise, such as demagnetization of permanent magnets, increased resistivity of conductive materials, insulation effect, and thermal strain, have become increasingly prominent, seriously restricting the performance and reliability of the device. In response to the above problems, although the finite element method can accurately predict the temperature rise of permanent magnets and conductor cylinders, compared with the equivalent thermal network model, its calculation efficiency is low and it occupies a large amount of resources. The present invention constructs an electromagnetic - temperature field coupling model for predicting the temperature rise of permanent magnets and conductor cylinders of an eddy current damper based on an equivalent magnetic circuit model and an equivalent thermal network model, and through the method of multi - variable mapping, realizes the heat generation under dynamic conditions and the collaborative analysis of the temperature rise of permanent magnets and conductor cylinders, providing a theoretical tool for the design and thermal management of eddy current dampers. Summary of the Invention

[0003] The purpose of the present invention is to provide a calculation method of electromagnetic - temperature field coupling for predicting the temperature rise change of permanent magnets and conductor cylinders of an eddy current damper, providing a theoretical tool for the thermal design of eddy current dampers.

[0004] The technical solution for achieving the purpose of the present invention is as follows: A calculation method for the temperature rise of permanent magnets and conductor cylinders of an eddy current damper based on electromagnetic - temperature field coupling, comprising the following steps:

[0005] Step 1, according to the structure of the eddy current damper, construct an equivalent magnetic circuit model considering magnetic saturation effect, skin effect, and end effect, and derive the analytical formula of eddy current loss;

[0006] Step 2, on the basis of calculating the eddy current loss by the equivalent magnetic circuit model, through the method of multi - variable mapping, associate the moving speed of the permanent magnet, the temperatures of the permanent magnet and the conductor cylinder with the eddy current loss, and use it as the basis for inputting the heat source of the temperature field;

[0007] Step 3, treat the eddy current loss of the electromagnetic field as the heat source of the temperature field, combine the equivalent T - type thermal path and the Nusselt correlation formula to solve the conduction thermal resistance and the convection thermal resistance, thereby build an equivalent thermal network model, and calculate the temperature rise of the permanent magnet and the conductor cylinder.

[0008] A calculation system for the temperature rise of the permanent magnet and the conductor cylinder of an eddy current damper based on electromagnetic-thermal field coupling, implementing the calculation method for the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper based on electromagnetic-thermal field coupling, realizing the calculation of the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper based on electromagnetic-thermal field coupling, and respectively executing steps 1 to 3 in three modules.

[0009] A computer device includes a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, it implements the calculation method for the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper based on electromagnetic-thermal field coupling, and realizes the calculation of the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper based on electromagnetic-thermal field coupling.

[0010] A computer-readable storage medium stores a computer program. When the computer program is executed by a processor, it implements the calculation method for the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper based on electromagnetic-thermal field coupling, and realizes the calculation of the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper based on electromagnetic-thermal field coupling.

[0011] Compared with the existing technical solutions, the remarkable feature of the present invention is that on the basis of considering the magnetic saturation effect, skin effect, and end effect of the electromagnetic field, the influence of the operating speed and temperature of the permanent magnet on the remanent flux density of the permanent magnet and the conductivity of the conductor cylinder is further incorporated into the construction of the analytical model, and the operating speed of the permanent magnet, the temperature of the conductor cylinder, and the temperature of the permanent magnet are associated with the eddy current loss through a multi-variable mapping method, thereby building a calculation model for the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper based on electromagnetic-thermal field coupling, which can not only be used to predict the temperature rise changes of the permanent magnet and the conductor cylinder, but also quantitatively analyze the non-linear change law of the eddy current loss in the conductor cylinder with the temperature rise, providing a corresponding theoretical tool for the thermal design and magnetic-thermal coupling analysis of the eddy current damper. Brief Description of the Drawings

[0012] Figure 1 It is a flowchart of the calculation method for the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper based on electromagnetic-thermal field coupling.

[0013] Figure 2 It is a schematic diagram of the structure of the eddy current damper.

[0014] Figure 3 It is a local magnetic flux path diagram.

[0015] Figure 4 It is a local equivalent magnetic circuit diagram.

[0016] Figure 5 It is a schematic diagram of applying Ampere's circuital law to a single eddy current.

[0017] Figure 6 It is a flowchart for the iteration of relative permeability.

[0018] Figure 7 It is a schematic diagram of end leakage flux.

[0019] Figure 8 It is a complete equivalent magnetic circuit diagram.

[0020] Figure 9 It is a diagram for the equivalent T-shaped thermal path division of a ring-shaped component.

[0021] Figure 10 It is a diagram for the equivalent T-shaped thermal path division of a cylindrical component.

[0022] Figure 11 It is a diagram for the division of the convective heat transfer surface of an eddy current damper.

[0023] Figure 12 It is a diagram of the equivalent thermal network model of an eddy current damper.

[0024] Figure 13 It is a comparison diagram of the braking force of an eddy current damper within 20 m / s.

[0025] Figure 14 It is a comparison diagram of the temperature rise of a permanent magnet and a conductor cylinder within 600 seconds.

[0026] Figure 15 It is a comparison diagram of the temperature rise of a conductor cylinder within 4800 seconds. Specific implementation manners

[0027] The following further illustrates the solution of the present invention in conjunction with the accompanying drawings and embodiments.

[0028] As Figure 1 shown, it is a flowchart of a calculation method for the temperature rise of a permanent magnet and a conductor cylinder of an eddy current damper based on electromagnetic-thermal field coupling. The specific steps are as follows:

[0029] Step 1: Construction of the equivalent magnetic circuit model of the eddy current damper, and its modeling process is as follows:

[0030] As Figure 2The structural schematic diagram of the eddy current damper is shown. The eddy current damper can be divided into two parts: the mover and the stator. Among them, the stator part consists of a double-layer composite cylinder and two end caps at the top and bottom. The outer layer of the composite cylinder is the back iron cylinder, and the inner layer is the conductor cylinder. The mover part is composed of a moving rod, a guide ring, pole shoes, permanent magnets, and nuts, and is installed inside the composite cylinder. The moving rod drives the guide ring, pole shoes, permanent magnets, and nuts to form a relative motion with the stator. The pole shoes and permanent magnets form a magnetic group, and the two are arranged in a reciprocating and alternating manner. The permanent magnets are axially magnetized and the magnetism between adjacent permanent magnets is opposite. The pole shoes are used to convert the axial magnetic flux into radial magnetic flux, and the inner and outer diameters of the permanent magnets and pole shoes are the same. The guide ring and nuts are installed on the moving rod to play a role in assembly positioning. The guide ring, nut, moving rod, and end cap are all made of non-magnetic materials to ensure the stable electromagnetic performance of the damper;

[0031] Among them, the pole pitch is τ, the inner diameter of the permanent magnet is r1, the outer diameter of the permanent magnet is r2, the axial length of the permanent magnet is b, the axial length of the pole shoe is c, the thickness of the air gap is g, and the thickness of the conductor cylinder is h ct , the outer diameter of the conductor cylinder is r ct , the outer diameter of the back iron cylinder is r bt ;

[0032] Considering the periodicity of the magnetic group array, according to Figure 2 the magnetic flux loop distribution of the local magnetic group at the red dotted box in Figure 3 i.e., the local magnetic flux path diagram shown in Figure 4 , a local equivalent magnetic circuit diagram is built, as shown in Figure 3 ; among them,

[0033] the calculation methods of the magnetic resistance elements of each magnetic flux loop are as follows:

[0034]

[0035] r jx =(r2 - r1) / 5 + r1(11)

[0036] τ = b + c(12)In the formula, F pm is the magnetomotive force of the permanent magnet, R pm , R bt and R gmare the common reluctances of the permanent magnet, the back iron cylinder, the air gap, and the conductor cylinder respectively; R jx1 , R jx2 are the reluctances of the pole shoes in the magnetic flux circuits 1 and 2; R gl , R pb are the leakage magnetic reluctances of the pole shoes at the air gap; R l2 is the leakage magnetic reluctance between adjacent pole shoes; R g is the parallel magnetic reluctance of the leakage magnetic flux of the pole shoes at the air gap and the common magnetic reluctance of the air gap and the inner cylinder; B r is the residual magnetic flux density of the permanent magnet; u bt is the relative permeability of the back iron cylinder; r jx is the outer diameter of the pole shoe reluctance 1; u jx1 is the relative permeability of the pole shoe 1, u jx2 is the relative permeability of the pole shoe 2; u0 is the permeability of free space;

[0037] Applying Kirchhoff's magnetic circuit law, the relationships between the reluctances are obtained as follows:

[0038]

[0039] where Φ2 and Φ2 are the magnetic fluxes in different magnetic paths;

[0040] Solving for the amplitude of the magnetic flux density in the conductor cylinder under static conditions and fitting the magnetic flux density in its transition region with a linear function, the expression for the magnetic flux density in the conductor cylinder under static conditions is finally obtained as follows:

[0041]

[0042] where, B g is the amplitude of the magnetic flux density in the conductor cylinder under static conditions, B pm (x) is the magnetic flux density in the conductor cylinder under static conditions;

[0043] Selecting a single eddy current region and applying Ampere's circuital law, i.e., Figure 5 as shown, and combining with the actual thickness of the induced current, the following formula can be derived:

[0044]

[0045] where, J(x) is the induced current density, B z (x) is the effective magnetic flux density, B cs( x) is the induced magnetic flux density caused by the eddy current, v is the moving speed of the magnetic reluctance, σ c t is the electrical conductivity of the conductor, L cs is the thickness of the eddy current;

[0046] Solving the above formula, the general solution of the induced magnetic flux density in the conductor cylinder can be obtained as follows:

[0047]

[0048] The unknown coefficients k1, k2, and k3 can be solved according to the continuity boundary conditions and the main boundary conditions, where the continuity boundary conditions and the main boundary conditions are as follows:

[0049] B cs2 (x0) = 0 (21)

[0050]

[0051] To avoid the influence of the magnetic saturation effect on the relative permeability of the magnetic conductive material, the iterative process shown in Figure 6 is used to solve the relative permeability of the pole shoe and the back iron cylinder. The iterative process is summarized as follows:

[0052] First, given the reluctances R jx1 , R jx2 , R bt of the initial relative permeability, the reluctances of each part in the equivalent magnetic circuit model and the values of the magnetic fluxes Φ1 and Φ2 are calculated according to the given initial relative permeability, and the magnetic induction intensities of the reluctances R jx1 , R jx2 , R bt are calculated according to the following formula:

[0053]

[0054] In the formula, B jxi , Φ i , A jxi are the magnetic induction intensity, magnetic flux, and magnetic flux area of the pole shoe reluctance respectively; the subscript i is used to represent different pole shoe reluctances, and the value is 1 or 2; B bt , A bt are the magnetic induction intensity and magnetic flux area of the back iron cylinder reluctance respectively;

[0055] Secondly, the magnetic induction intensity B is substituted into the B-H curve for comparison, the corresponding magnetic field intensity H is found, and the relative permeability u r is solved. Its calculation method is as follows:

[0056]

[0057] In the formula, k is the iteration coefficient; d is the damping coefficient, and the general value is 0.1; u jxi is the relative permeability of different pole shoe reluctances; is the intermediate permeability of different pole shoe reluctances and back iron reluctances;

[0058] Finally, the calculated relative permeabilities u jxi and u btPut it into the judgment condition for statement judgment. If the requirements are met, the corresponding magnetic flux Φ will be output i and magnetic induction intensity B jxi 、B bt and relative magnetic permeability u jx1 、u jx2 、u bt ; Otherwise, continue to iterate until all iteration conditions are met. The judgment conditions are as follows:

[0059] |[u jxi (k) -u jxi (k-1) / u jxi (k-1) |≤ε (31)

[0060] |[u bt (k) -u bt (k-1) / u bt (k-1) |≤ε (32) In the formula, ε is the termination coefficient, and its value is 0.001;

[0061] Therefore, considering the magnetic saturation effect and skin effect, the expressions of the induced magnetic flux density, braking force, and eddy current loss of the conductor cylinder are as follows:

[0062]

[0063]

[0064] In the formula, V is the volume of the eddy current region under a single magnetic group, N jx is the number of pole shoes, F is the braking force, and P is the eddy current loss of the conductor cylinder;

[0065] As Figure 7 shown, in the process of constructing the above equivalent magnetic circuit model, in order to simplify the calculation, it is always assumed that the number of magnetic groups is infinite, ignoring the end leakage magnetic phenomenon caused by the limited number of actual magnetic groups. That is, compared with the above local magnetic flux path, there is an additional leakage magnetic path in the end magnetic group region that forms a closed loop after starting from the pole shoe, passing through the external air, conductor cylinder, back iron cylinder, and air gap. This newly added leakage magnetic path makes the magnetic flux distribution in the end region more complex; To accurately reflect the end leakage magnetic effect, it is necessary to construct a complete equivalent magnetic circuit diagram as Figure 8 shown to solve the end leakage magnetic and further derive the end effect correction coefficient to correct the braking force and eddy current loss. The end leakage magnetic calculation is as follows:

[0066]

[0067] R ge=R gl3 / / R gm / / R pb / / (0.5R gl1 )(38)In the formula, R gl3 is the end leakage flux, R ge is the total parallel reluctance of the end region reluctance, V lg3 R gl3 The average magnetic flux leakage volume;

[0068] Taking into account the symmetry of the magnetic flux loop in the complete equivalent magnetic circuit model, the following equation can be obtained:

[0069] Where, Φ 1，N and Φ 2，N are the magnetic flux of different magnetic flux circuits, R jx1,N and R jx2,N is the magnetic resistance of the pole shoes in different magnetic flux circuits, N is the number of permanent magnets;

[0070] By solving formula 39-41, the magnetic flux density B of the conductor tube in the end area can be obtained. g1 and B g2 , and then the expression of the end effect correction coefficient is deduced as follows:

[0071]

[0072] Where B g1 and B g2 is the end magnetic flux density, K e is the end effect correction factor.

[0073] The corrected expressions for braking force and eddy current loss are as follows:

[0074]

[0075] Where, F e is the corrected braking force, P e To correct the eddy current loss of the conductor tube.

[0076] By rewriting the above mathematical model into a calculation program in MATLAB, the eddy current loss and braking force inside the conductor tube can be easily calculated, which provides a heat source basis for subsequent temperature field modeling and analysis.

[0077] In step 2, based on the calculation of eddy current loss using the equivalent magnetic circuit model, the speed of the permanent magnet, the temperature of the permanent magnet and the conductor tube are correlated with the eddy current loss through multivariate mapping and used as the heat source input basis for the temperature field. The specific method is as follows:

[0078] Combined with the equivalent magnetic circuit model and the relationships between the remanent flux density of the permanent magnet and the conductivity of the conductor cylinder and temperature, calculate the eddy current loss of the conductor cylinder under different moving speeds of the permanent magnet and different combinations of the conductor cylinder temperature and the permanent magnet temperature. Taking the eddy current loss of the conductor cylinder at different moving speeds of the permanent magnet when both the permanent magnet and the conductor cylinder are at 20 °C as the reference, associate the eddy current loss with the moving speed of the permanent magnet, the conductor cylinder temperature, and the permanent magnet temperature through a multi - variable mapping method. Its general mapping relationship formula is shown in Formula 47;

[0079]

[0080] σ(T dt ) = σ0 + α(T dt - T0)(46)

[0081] P g = P[[ID=!6]] e (v)·f(T pm , T dt )(In Formula (47), α Br is the temperature coefficient of the remanent flux density of the permanent magnet, B r (T pm ) is the remanent flux density of the permanent magnet at temperature T pm , B r (T0) is the remanent flux density of the permanent magnet at temperature T0; σ(T dt ) is the conductivity of the conductor cylinder at temperature T dt , α is the temperature coefficient of the conductivity of the conductor cylinder, σ0 is the conductivity of the conductor cylinder at temperature T0; P e (v) is the eddy current loss of the conductor cylinder at different moving speeds of the permanent magnet when both the permanent magnet and the conductor cylinder are at 20 °C; P g is the eddy current loss in the conductor cylinder at any temperature of the permanent magnet and the conductor cylinder and at any moving speed of the permanent magnet, and f(T pm , T dt ) is the mapping relationship formula of the eddy current loss of the conductor cylinder at different permanent magnet temperatures and conductor cylinder temperatures.

[0082] In Step 3, treat the eddy current loss of the electromagnetic field as the heat source of the temperature field, solve the conduction thermal resistance and the convective thermal resistance by combining the equivalent T - type thermal circuit and the Nusselt correlation formula, and build an equivalent thermal network model, and then calculate the temperature rise of the permanent magnet and the conductor cylinder:

[0083] (1) Analysis of heat transfer paths

[0084] Combined with the geometric structure of the eddy current damper and the heat transfer methods of heat conduction and heat convection, there are the following three heat transfer paths from the conductor cylinder, which is the starting point of heat transfer of the eddy current damper, to the external environment, which is the end point of heat transfer:

[0085] 1). The heat energy generated by eddy current loss is transferred inside the conductor cylinder and the back iron cylinder in the form of heat conduction, and finally transferred to the environment by heat convection in the radial direction through the outer surface of the back iron cylinder;

[0086] 2). The heat energy generated by eddy current loss is transferred from the composite cylinder to the end cover axially by heat conduction, and transferred to the air in the cavity by convective heat transfer from the inner surface of the conductor cylinder in the radial direction, and transferred to the end cover by heat convection, and finally lost in the environment by heat convection;

[0087] 3). The heat energy generated by eddy current loss is transferred from the inner surface of the conductor cylinder to the guide ring by heat conduction and to the air in the cavity by heat convection. The air in the cavity is transferred to the nut, magnetic group, guide ring, and moving rod by convective heat transfer. After the nut, magnetic group, and guide ring are transferred to the moving rod by heat conduction, they are dissipated in the environment by forced convective heat transfer;

[0088] (2) Construction of equivalent thermal network model

[0089] There are two ways of heat transfer inside the eddy current damper. One is to consider the heat transfer between solids, and the other is to consider the heat convection between solids and air. Therefore, the equivalent thermal network model consists of four components: convective thermal resistance, conductive thermal resistance, heat capacity, and heat source. The input of the heat source part comes from the eddy current loss of the electromagnetic field;

[0090] According to the different structural materials of the eddy current damper, the equivalent thermal network model can be divided into the following regions: back iron cylinder region, conductor cylinder region, upper end cover region, lower end cover region, nut region, guide ring region, pole shoe region, permanent magnet region, moving rod region, air region in the cavity, external environment region; Connect the heat transfer nodes between the regions according to the above three heat transfer paths starting from the conductor cylinder as the heat transfer starting point of the eddy current damper and ending at the external environment as the heat transfer end point, and the temperature field of the eddy current damper can be transformed into an equivalent thermal network model; The composition method of the internal heat path and the calculation of the thermal resistance in each region are as follows:

[0091] The back iron cylinder, conductor cylinder, nut, guide ring, pole shoe, permanent magnet, and lower end cover are of circular geometric structures. Therefore, the heat conduction paths in the corresponding regions are represented by the equivalent T-shaped heat path. The equivalent T-shaped heat path is composed of the conductive thermal resistances R a1 、R a2 and R a3 representing the axial heat conduction inside the solid, and the conductive thermal resistances R r1 、R r2 and R r3 representing the radial heat conduction inside the solid, as well as the heat capacity C and the heat source P, that is, as shown in Figure 9 The connection method is as follows:

[0092] Thermal resistance R a3 and thermal resistance R r3 share a common node, which represents the bulk average temperature of the corresponding component, and the heat capacity C and heat source P of the corresponding component are also connected to this node. Thermal resistance R a3 and thermal resistance R r3 's other node is respectively shared with thermal resistance R a1 , thermal resistance R a2 , thermal resistance R r1 and thermal resistance R r2 . Thermal resistance R a1 's other node represents the average temperature of the left side surface of the toroidal component. Thermal resistance R a2 's other node represents the average temperature of the right side surface of the toroidal component. R r1 's other node represents the average temperature of the inner surface of the toroidal component. R r2 's other node represents the average temperature of the outer surface of the toroidal component;

[0093] The calculation method of the relevant thermal resistance is as follows:

[0094]

[0095] In the formula, r in and r out are the inner diameter and outer diameter of the ring; H is the thickness of the ring; k is the thermal conductivity;

[0096] The moving rod has a cylindrical geometric structure, and its heat conduction path consists of the conduction thermal resistance R a5 representing axial heat transfer and thermal resistance R a6 and the conduction thermal resistance R r7 representing radial heat transfer, as well as the heat capacity C and heat source P, that is, as shown in Figure 10 . The corresponding connection method is briefly described as follows: Heat source P, heat capacity C, thermal resistance R a5 , thermal resistance R a6 and thermal resistance R r7 share the node representing the bulk average temperature. The other node of thermal resistance R a5 represents the average temperature of the left side surface of the cylindrical component. The other node of thermal resistance R a6 represents the average temperature of the right side surface of the cylindrical component. The other node of thermal resistance R r7 represents the average temperature of the outer surface of the cylindrical component. The calculation method of the corresponding thermal resistance is as follows:

[0097]

[0098] In the formula, r is the radius of the cylinder; l is the length of the cylinder;

[0099] Since there are multiple through-holes on the upper end cover with their centers on the same circumference and equal radii, the through-hole area is equivalently treated as a circular ring. Thus, the heat transfer path in the upper end cover area consists of a circular-ring-shaped heat conduction path, a cylindrical heat conduction path, and a heat convection path for connecting the radial heat transfer between the two;

[0100] The heat capacity of the components in each area is calculated as follows:

[0101] C = C p m(55)

[0102] In the formula, m is the mass, with the unit of kg;

[0103] In the composition of the heat conduction paths in the above-mentioned areas, only the conductor cylinder and the back iron cylinder areas have heat sources, and the size of the heat source is the eddy current loss of the eddy current damper;

[0104] The heat transfer paths in the cavity air area and the external environment area consist of heat convection paths representing the convective heat transfer between the solid and the air. The calculation method of the convective heat resistance is as follows:

[0105]

[0106] In the formula, R con is the convective heat resistance, A con is the area of each convective heat transfer surface; h is the convective heat transfer coefficient;

[0107] To accurately calculate the convective heat resistance in the cavity air area and the external environment area, the convective heat transfer surfaces of the eddy current damper are divided and numbered, as shown in Figure 11 . At the same time, a dimensionless number is introduced and associated with the convective heat transfer coefficient to calculate the convective heat transfer coefficient of each convective heat transfer surface. The division and numbering of each convective heat transfer surface are as follows:

[0108] The outer surfaces of the back iron cylinder and the upper and lower end covers are marked as surface 1; the left axial surface of the upper end cover facing the external environment is marked as surface 3, the right axial surface facing the upper air cavity inside the conductor cylinder is marked as surface 4, the through-hole area in the upper end cover is equivalently treated as a ring with the same radius, the inner diameter surface of the ring is marked as surface 6, and the outer diameter surface of the ring is marked as surface 5; the right axial surface of the lower end cover facing the external environment is marked as surface 2, the left axial surface facing the lower air cavity inside the conductor cylinder is marked as surface 12, and the inner surface facing the moving rod is marked as surface 18; to ensure the moment correspondence of the eddy current losses of the magnetic group and the conductor cylinder in terms of spatial position, the inner surface of the conductor cylinder is divided into three parts, namely the inner surfaces 7 and 15 facing the upper and lower air cavities and the inner surface 21 at the air gap; the outer surface of the nut is marked as surface 11, and the left axial surface facing the upper air cavity is marked as surface 8; the left axial surface of the guide ring in the upper air cavity area is marked as surface 10, and the right axial surface facing the air gap is marked as surface 20; the right axial surface of the guide ring in the lower air cavity area is marked as surface 14, and the left axial surface facing the air gap is marked as surface 23; since the inner and outer diameters of the permanent magnet and the pole shoe are the same, the same marked surface is used for their outer surfaces, that is, the outer surface facing the air gap is marked as surface 22; the left axial surface of the moving rod facing the upper air cavity is marked as surface 9, the partial outer surface facing the lower air cavity is marked as surface 13, the partial outer surface facing the lower end cover is marked as surface 17, and the partial outer surface and the right axial surface facing the external environment are surface 19 and surface 16 respectively;

[0109] The calculation method of the dimensionless number is as follows:

[0110]

[0111] In the formula, N u is the Nusselt number; R e is the Reynolds number; P r is the Planck number; G r is the Grashof number; L is the characteristic length; ρ is the fluid density; v is the fluid velocity; μ is the dynamic viscosity of the fluid; g is the acceleration due to gravity; β is the coefficient of volume expansion of the fluid; θ is the temperature difference between the fluid and the solid on the convective heat transfer surface; λ is the thermal conductivity;

[0112] The calculation method of the convective heat transfer coefficient of each convective heat transfer surface is as follows:

[0113] Surface 1 is regarded as the natural convective heat transfer of a horizontally placed outer cylindrical wall surface, and the calculation method of its convective heat transfer coefficient is as follows:

[0114]

[0115]

[0116] In the formula, D is the cylinder diameter, that is, the outer diameter of the back iron cylinder.

[0117] The natural convection heat transfer between Surface 2 and Surface 3 is regarded as that under a vertical wall surface, and its convective heat transfer coefficient is calculated as follows:

[0118]

[0119] Surface 19 is calculated using the classical heat dissipation formula. The surface fluid velocity is the same as that of the moving rod, and the convective heat transfer coefficient is calculated as follows:

[0120]

[0121] In the formula, T f is the ambient temperature;

[0122] The forced convection heat transfer on Surfaces 4, 8 - 10, 12, 14, 16, 20, and 23 can be regarded as that on a vertical flat plate. Its convective heat transfer coefficient can be solved according to the Nusselt number, that is, Equation 57. The experimental correlation of the relevant Nusselt number is as follows:

[0123] N u =0.16R e 0.699 (66)

[0124] Surfaces 5 - 7, 11, 13, 15, 17, 18, 21, and 22 can be regarded as the flow in a concentric circular pipe, and the calculated value of R e is less than 2300, so it is laminar flow. Therefore, the Nusselt number can be calculated according to Table 1 below, and the corresponding convective heat transfer coefficient can be calculated in combination with Equation 57;

[0125] Table 1 Nusselt number selection table

[0126]

[0127] With the help of the lumped heat system module in the COMSOL simulation software, an equivalent thermal network model of the eddy current damper as shown Figure 12 is manually built according to the heat source, heat capacity, and thermal resistance solved by Equations 47 - 66, and then the temperature rises of the permanent magnet and the conductor cylinder can be calculated.

[0128] Note: The equivalent T - type thermal path method is only used to describe the heat conduction in the axial and radial directions inside the solid components and the corresponding thermal resistance. The heat capacity is an inherent property of the substance when absorbing or releasing heat and is part of the equivalent thermal network model. Because during the transient analysis process, heat will be temporarily stored in the material, resulting in the temperature not being able to respond instantaneously (similar to the charging and discharging of a capacitor in an electric circuit). This COMSOL software is only convenient for solving the equivalent thermal network model built by oneself and only serves as a calculator.

[0129] The present invention also provides a calculation system for the temperature rise of the permanent magnet and the conductor cylinder of an eddy current damper based on electromagnetic-thermal field coupling, which implements the calculation method for the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper based on electromagnetic-thermal field coupling, realizes the calculation of the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper based on electromagnetic-thermal field coupling, and respectively executes steps 1 to 3 in three modules.

[0130] A computer device includes a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the calculation method for the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper based on electromagnetic-thermal field coupling is implemented, and the calculation of the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper based on electromagnetic-thermal field coupling is realized.

[0131] A computer-readable storage medium stores a computer program thereon. When the computer program is executed by a processor, the calculation method for the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper based on electromagnetic-thermal field coupling is implemented, and the calculation of the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper based on electromagnetic-thermal field coupling is realized.

[0132] Embodiment

[0133] To verify the solution of the present invention, the following calculations are performed.

[0134] In this case, the equivalent magnetic circuit model of the electromagnetic field is rewritten into a calculation program suitable for running in MATLAB to solve the eddy current loss of the eddy current damper. At the same time, the eddy current loss results of multiple groups of permanent magnets at different operating speeds, different conductor cylinder temperatures, and permanent magnet temperature combinations are calculated, and the eddy current loss is correlated with the operating speed of the permanent magnet, the conductor cylinder temperature, and the permanent magnet temperature based on the method of multivariate mapping, which is used as the heat source input basis for the equivalent thermal network model. With the help of the lumped parameter thermal system module in the COMSOL simulation software, by inputting the corresponding conduction thermal resistance, convective thermal resistance, heat capacity, and heat source, an equivalent thermal network model of the eddy current damper is constructed and the temperature rise of the conductor cylinder and the permanent magnet is calculated. Figure 13 The figure shows the comparison diagram between the braking force results calculated by the equivalent magnetic circuit model within 20 m / s and the finite element data. It can be seen that the error of the eddy current resistance is within 5% within 0 - 5 m / s, and the error of the eddy current resistance is within 5% - 10% within 10 - 20 m / s. The overall normalized root mean square deviation is 5.22%, meeting the engineering error, which provides a heat source basis for the subsequent modeling analysis of the temperature field. Figure 14 The figure shows the comparison diagram between the temperature rise results of the conductor cylinder and the permanent magnet calculated by the equivalent thermal network model within 600 seconds and the finite element calculation results. The results show that the calculation results of the equivalent thermal network model are consistent with the finite element simulation results. Figure 15The figure shows the comparison between the temperature rise results of the conductor cylinder calculated by the equivalent thermal network model within 4800 seconds and the experimental data. It can be seen that the temperature rise trends of the two are consistent, the maximum temperature rise deviation is 1.84 °C, and the normalized root mean square deviation is 3.64%, meeting the engineering requirements. At the same time, the heat source decay rate in the conductor cylinder reaches 11.5% at 4800 seconds, verifying the necessity of the coupled modeling of the temperature field and the electromagnetic field. To sum up, this method can be used as a theoretical calculation tool for the thermal design of the eddy current damper.

Claims

1. A calculation method for the temperature rise of the permanent magnet and the conductor cylinder of an eddy current damper based on electromagnetic-temperature field coupling, characterized by the following steps: Step 1, according to the structure of the eddy current damper, construct an equivalent magnetic circuit model considering magnetic saturation effect, skin effect and end effect, and derive the analytical formula of eddy current loss; Step 2, on the basis of calculating the eddy current loss by the equivalent magnetic circuit model, through the method of multi-element mapping, associate the moving speed of the permanent magnet, the temperatures of the permanent magnet and the conductor cylinder with the eddy current loss, and use it as the heat source input basis of the temperature field; Step 3, treat the eddy current loss of the electromagnetic field as the heat source of the temperature field, combine the equivalent T-shaped thermal circuit and the Nusselt correlation formula to solve the conduction thermal resistance and the convection thermal resistance, thereby build an equivalent thermal network model to calculate the temperature rise of the permanent magnet and the conductor cylinder.

2. The calculation method for the temperature rise of the permanent magnet and the conductor cylinder of an eddy current damper based on electromagnetic-temperature field coupling according to claim 1, characterized in that in Step 1, according to the structure of the eddy current damper, construct an equivalent magnetic circuit model considering magnetic saturation effect, skin effect and end effect, and determine the analytical formula of eddy current loss. The specific method is as follows: (1) The basic structure of the eddy current damper The structure of the eddy current damper is divided into two parts: the mover and the stator, where The stator part consists of a double-layer composite cylinder and two end caps on the upper and lower sides. The outer layer of the composite cylinder is a back iron cylinder, and the inner layer is a conductor cylinder; The mover part consists of a moving rod, a guide ring, a pole shoe, a permanent magnet and a nut, and is installed inside the composite cylinder. The moving rod drives the guide ring, the pole shoe, the permanent magnet and the nut to form a relative motion with the stator; the pole shoe and the permanent magnet form a magnetic group, and the two are arranged in a reciprocating and alternating manner; the permanent magnet is axially magnetized and the magnetism between adjacent permanent magnets is opposite. The pole shoe is used to convert the axial magnetic flux into radial magnetic flux, and the inner and outer diameters of the permanent magnet and the pole shoe are the same; the guide ring and the nut are installed on the moving rod to play the role of assembly positioning; The guide ring, the nut, the moving rod and the end cap are all made of non-magnetic materials to ensure the stable electromagnetic performance of the damper; (2) The structural parameters of the eddy current damper The pole pitch is τ, the inner diameter of the permanent magnet is r1, the outer diameter of the permanent magnet is r2, the axial length of the permanent magnet is b, the axial length of the pole shoe is c, the thickness of the air gap is g, and the thickness of the conductor cylinder is h ct , the outer diameter of the conductor cylinder is r ct , the outer diameter of the back iron cylinder is r bt ; (3) Construction of the local equivalent magnetic circuit model Considering the symmetry of the geometric structure of the eddy current damper, based on the magnetic flux loop path of any magnetic group in the middle region, construct a local equivalent magnetic circuit model, including the following two magnetic flux loops: The main magnetic flux path starts from the permanent magnet, passes through the pole shoe, the air gap, the conductor cylinder and the back iron cylinder in sequence, and then returns to the permanent magnet to form a closed loop 1; The leakage magnetic flux path exists between adjacent pole shoes and in the air gap and conductor cylinder regions: between adjacent pole shoes, part of the leakage magnetic flux starts from the pole shoe, passes through the moving rod and then returns to the pole shoe to form a closed loop 2; in the air gap and conductor cylinder regions, the leakage magnetic flux starts from the pole shoe, passes through the air gap and the conductor cylinder, and forms a local closed loop in the closed loop 1; The magnetic resistance elements of each magnetic flux loop are calculated as follows: r jx =(r2 - r1) / 5 + r1 (11) τ = b + c (12) In the formula, F pm is the magnetomotive force of the permanent magnet, R pm , R bt and R gm are respectively the magnetic resistance of the permanent magnet, the magnetic resistance of the back iron cylinder, the common magnetic resistance of the air gap and the conductor cylinder; R jx1 , R jx2 are the magnetic resistances of the pole shoe on the magnetic flux circuit 1 and the magnetic flux circuit 2; R gl1 , R pb are the magnetic resistances of the leakage magnetic flux of the pole shoe at the air gap; R l2 is the magnetic resistance of the leakage magnetic flux of the pole shoe at the moving rod; R g is the parallel magnetic resistance of the leakage magnetic flux of the pole shoe at the air gap and the common magnetic resistance of the air gap and the inner cylinder; B r is the remanent magnetic flux density of the permanent magnet; u bt is the relative magnetic permeability of the back iron cylinder; r jx is the outer diameter of the magnetic resistance 1 of the pole shoe; u jx1 is the relative magnetic permeability of the pole shoe 1, u jx2 is the relative magnetic permeability of the pole shoe 2; u0 is the permeability of free space; Using Kirchhoff's magnetic circuit law, the relationship between magnetic resistances is obtained as follows: Where Φ2 and Φ2 are the magnetic fluxes in different magnetic paths; Solve the amplitude of the magnetic flux density in the conductor cylinder under static conditions, and perform a linear function fitting on the magnetic flux density in its transition region. Finally, the magnetic flux density expression of the conductor cylinder under static conditions is as follows: where B g is the amplitude of the magnetic flux density of the conductor cylinder under static conditions, and B pm (x) is the magnetic flux density of the conductor cylinder under static conditions; (4) Solving the induced magnetic flux density, braking force, and eddy current loss of the conductor cylinder under transient conditions According to the principle of electromagnetic induction, the braking force in the conductor cylinder is generated by the interaction between the induced magnetic field excited by the eddy current and the main magnetic field generated by the permanent magnet. Therefore, in the local equivalent magnetic circuit model, a single eddy current is selected, combined with the actual thickness of the induced current, and the Ampere's circuital law is applied to obtain: Wherein, J(x) is the induced current density, B z (x) is the effective magnetic flux density, B cs( x) is the induced magnetic flux density caused by eddy current, v is the moving speed of the reluctance, σ ct is the conductivity of the conductor, L cs is the thickness of the eddy current; By solving, the general solution of the induced magnetic flux density in the conductor cylinder is as follows: The unknown coefficients k1, k2, and k3 are solved according to the continuity boundary condition and the main boundary condition, where the continuity boundary condition and the main boundary condition are as follows: B cs2 (x0) = 0(21) To avoid the influence of the magnetic saturation effect on the relative magnetic permeability of the magnetic conductive material, an iterative calculation method is used to solve the relative magnetic permeability of the pole shoe and the back iron cylinder, and its iterative calculation process is as follows: First, given the magnetoresistance R jx1 , R jx2 , R bt 's initial relative permeability, calculate the magnetoresistance magnitudes of each part in the equivalent magnetic circuit model and the values of magnetic fluxes Φ1 and Φ2 according to the given initial relative permeability, and calculate the magnetic induction intensities of magnetoresistances R jx1 , R jx2 , R bt according to the following formula; In the formula, B jxi , Φ i , A jxi are the magnetic induction intensity, magnetic flux and magnetic flux area of the pole shoe magnetic resistance respectively; the subscript i is used to represent different pole shoe magnetic resistances and takes the value of 1 or 2; B bt , A bt are the magnetic induction intensity and magnetic flux area of the back iron cylinder magnetic resistance respectively; Secondly, substitute the magnetic induction intensity B into the B-H curve for comparison, find the corresponding magnetic field intensity H, and solve for the relative permeability μ r , and its calculation method is as follows: where k is the iteration coefficient; d is the damping coefficient; u jxi is the relative permeability of different pole shoe reluctances; is the intermediate permeability of different pole shoe reluctances and back iron reluctances; Finally, put the calculated relative permeability μ jxi and μ bt into the judgment condition for statement judgment. If the requirements are met, output the corresponding magnetic flux Φ i and magnetic induction intensity B jxi 、B bt and relative permeability μ jx1 、μ jx2 、μ bt ; otherwise, continue to iterate until all iteration conditions are met. The judgment conditions are as follows: |[u jxi (k) -u jxi (k-1) / u jxi (k-1) |≤ε (31) |[u bt (k) -u bt (k-1) / u bt (k-1) |≤ε (32) In the formula, ε is the termination coefficient; Therefore, the expressions for the induced magnetic flux density, braking force, and eddy current loss of the conductor cylinder considering the magnetic saturation effect and the skin effect are as follows: Wherein, V is the volume of the eddy current region under a single magnetic group, N jx is the number of pole shoes, F is the braking force, and P is the eddy current loss of the conductor cylinder; (5) End effect correction In practical applications, the number of magnetic groups is limited, and the end leakage magnetic phenomenon cannot be ignored. To accurately reflect the end leakage magnetic effect, a complete equivalent magnetic circuit model is constructed to solve the end leakage magnetic flux and further derive the end effect correction coefficient to correct the braking force and eddy current loss. The calculation of the end leakage magnetic resistance is as follows: R ge =R gl3 / / R gm / / R pb / / (0.5R gl1 )(38)In the formula, R gl3 is the end leakage magnetic resistance, R ge is the total parallel reluctance of the end region reluctance, V lg3 R gl3 The average magnetic flux leakage volume; Considering the symmetry of the magnetic flux loop in the complete equivalent magnetic circuit model, we get: Where Φ 1，N and Φ 2，N are the magnetic fluxes of different magnetic flux circuits respectively, R jx1,N and R jx2,N are the pole shoe magnetic resistances in different magnetic flux circuits, and N is the number of permanent magnets; By solving equations 39 - 41, the magnitude of the magnetic flux density B of the conductor cylinder in the end region is obtained g1 and B g2 , and then the expression of the end effect correction factor is derived as follows: where B g1 and B g2 are the end flux densities, and K e is the end effect correction factor; The expressions for the corrected braking force and eddy current loss are as follows: Where F e is the corrected braking force, and P e is the corrected eddy current loss of the conductor cylinder.

3. The calculation method for the temperature rise of the permanent magnet and the conductor cylinder of an eddy current damper based on electromagnetic-temperature field coupling according to claim 1, characterized in that in step 2, on the basis of calculating the eddy current loss in the equivalent magnetic circuit model, through the method of multi-element mapping, the motion speed of the permanent magnet, the temperatures of the permanent magnet and the conductor cylinder are associated with the eddy current loss and used as the heat source input basis for the temperature field. The specific method is: Combined with the equivalent magnetic circuit model, and the relationship between the residual magnetic flux density of the permanent magnet and the conductivity of the conductor cylinder and temperature, calculate the eddy current loss of the conductor cylinder under different motion speeds of the permanent magnet and different combinations of the temperatures of the conductor cylinder and the permanent magnet. Taking the eddy current loss of the conductor cylinder at 20 °C for both the permanent magnet and the conductor cylinder and different motion speeds of the permanent magnet as the reference, through the method of multi-element mapping, the eddy current loss is associated with the motion speed of the permanent magnet, the temperature of the conductor cylinder, and the temperature of the permanent magnet. Its general mapping relationship formula is shown in formula 47; σ(T dt ) = σ0 + α(T dt - T0)(46)P g = P e (v)·f(T pm , T dt )(47) In the formula, α Br is the temperature coefficient of the residual magnetic flux density of the permanent magnet, B r (T pm ) is the residual magnetic flux density of the permanent magnet at temperature T pm ; B r (T0) is the residual magnetic flux density of the permanent magnet at temperature T0; σ(T dt ) is the conductivity of the conductor cylinder at temperature T dt ; α is the temperature coefficient of the conductivity of the conductor cylinder, and σ0 is the conductivity of the conductor cylinder at temperature T0; P e (v) is the eddy current loss of the conductor cylinder at different moving speeds of the permanent magnet when the temperatures of both the permanent magnet and the conductor cylinder are 20°C; P g is the eddy current loss of the conductor cylinder at any temperature of the permanent magnet and the conductor cylinder and at any moving speed of the permanent magnet, and f(T pm , T dt ) is the mapping relationship formula of the eddy current loss of the conductor cylinder at different temperatures of the permanent magnet and the conductor cylinder.

4. The calculation method for the temperature rise of the permanent magnet and the conductor cylinder of an eddy current damper based on electromagnetic-temperature field coupling according to claim 1, characterized in that in step 3, the eddy current loss of the electromagnetic field is treated as the heat source of the temperature field, combined with the equivalent T-shaped thermal circuit and the Nusselt correlation formula to solve the conduction thermal resistance and the convection thermal resistance, and an equivalent thermal network model is built to further calculate the temperature rise of the permanent magnet and the conductor cylinder: (1) Heat transfer path analysis Combined with the geometric structure of the eddy current damper and the heat transfer methods of heat conduction and heat convection, there are the following three heat transfer paths from the conductor cylinder as the starting point of heat transfer of the eddy current damper to the external environment as the end point of heat transfer: 1). The heat energy generated by eddy current loss is transferred inside the conductor cylinder and the back iron cylinder in the form of heat conduction, and finally transferred to the environment in the form of heat convection through the outer surface of the back iron cylinder in the radial direction; 2). The heat energy generated by eddy current loss is transferred from the composite cylinder to the end cover axially through heat conduction, and transferred to the air in the cavity from the inner surface of the conductor cylinder through convective heat transfer, and transferred to the end cover in the form of heat convection, and finally dissipated in the environment through heat convection; 3). The heat energy generated by eddy current loss is transferred from the inner surface of the conductor cylinder to the guide ring by heat conduction and to the air in the cavity by heat convection. The air in the cavity is transferred to the nut, magnetic group, guide ring, and moving rod through convective heat transfer. After the nut, magnetic group, and guide ring are transferred to the moving rod by heat conduction, they are dissipated in the environment by forced convective heat transfer; (2) Construction of equivalent thermal network model The heat transfer methods inside the eddy current damper are divided into two types. One is to consider the heat transfer between solids, and the other is to consider the heat convection between solids and air. Therefore, the equivalent thermal network model consists of four components: convective thermal resistance, conductive thermal resistance, heat capacity, and heat source. The input of the heat source part comes from the eddy current loss of the electromagnetic field; According to the different structural materials of the eddy current damper, the equivalent thermal network model is divided into the following regions: back iron cylinder region, conductor cylinder region, upper end cover region, lower end cover region, nut region, guide ring region, pole shoe region, permanent magnet region, moving rod region, air region in the cavity, external environment region; Connect the heat transfer nodes between the corresponding regions according to the above three heat transfer paths starting from the conductor cylinder as the heat transfer starting point of the eddy current damper to the external environment as the heat transfer end point, that is, convert the temperature field of the eddy current damper into an equivalent thermal network model; The composition method of the internal heat path of each region and the calculation of thermal resistance are as follows: The back iron cylinder, conductor cylinder, nut, guide ring, pole shoe, permanent magnet, and lower end cover have a circular geometric structure. Therefore, the heat conduction paths in the corresponding regions are represented by an equivalent T-shaped thermal circuit, which consists of conduction thermal resistances R a1 、R a2 and R a3 representing axial heat conduction inside the solid, conduction thermal resistances R r1 、R r2 and R r3 representing radial heat conduction inside the solid, as well as heat capacity C and heat source P. Their connection is as follows: Thermal resistance R a3 and thermal resistance R r3 share a common node, which represents the bulk average temperature of the corresponding component and to which the heat capacity and heat source of the corresponding component are also connected. The other node of thermal resistance R a3 and thermal resistance R r3 is shared with thermal resistances R a1 , R a2 , R r1 and R r2 respectively. The other node of thermal resistance R a1 represents the average temperature of the left side surface of the annular component, the other node of thermal resistance R a2 represents the average temperature of the right side surface of the annular component, the other node of R r1 represents the average temperature of the inner surface of the annular component, and the other node of R r2 represents the average temperature of the outer surface of the annular component; The calculation methods of relevant thermal resistances are as follows: where r in and r out are the inner diameter and outer diameter of the ring; H is the thickness of the ring; k is the thermal conductivity; The motion rod has a cylindrical geometric structure, and its heat conduction path consists of a conduction thermal resistance R representing axial heat transfer a5 and a thermal resistance R a6 and a conduction thermal resistance R r7 as well as a heat capacity C and a heat source P. The corresponding connection methods are briefly described as follows: The thermal resistance R a5 , the thermal resistance R a6 and the thermal resistance R r7 share the node representing the bulk average temperature. Another node of the thermal resistance R a5 represents the average temperature of the left side surface of the cylindrical component, another node of the thermal resistance R a6 represents the average temperature of the right side surface of the cylindrical component, and another node of the thermal resistance R r7 represents the average temperature of the outer surface of the cylindrical component. The calculation methods of the corresponding thermal resistances are as follows: In the formula, r is the radius of the cylinder; l is the length of the cylinder; Since there are multiple through holes on the upper end cover with the same center on the same circumference and equal radii, the through hole region is equivalently treated as a ring. Then, the heat transfer path of the upper end cover region consists of a ring-shaped heat conduction path, a cylindrical heat conduction path, and a heat convection path for connecting the radial heat transfer of the two; The heat capacity calculations of the components in each region are as follows: C=C p In the formula m(55), m is the mass in kg; In the composition of the heat conduction paths of the above regions, only the conductor cylinder region and the back iron cylinder region have heat sources, and the size of the heat source is the size of the eddy current loss of the eddy current damper; The heat transfer paths of the air region in the cavity and the external environment region are composed of heat convection paths representing the convective heat transfer between solids and air. The calculation method of its convective thermal resistance is as follows: wherein, R con is the convective thermal resistance, A con is the area of each convective heat transfer surface; h is the convective heat transfer coefficient; To accurately calculate the convective thermal resistance in the air region in the cavity and the external environment region, divide and number the convective heat transfer surfaces of the eddy current damper, and at the same time introduce a dimensionless number related to the convective heat transfer coefficient to calculate the convective heat transfer coefficient of each convective heat transfer surface. The division and numbering of each convective heat transfer surface are as follows: The outer surfaces of the back iron cylinder and the upper and lower end covers are marked as surface 1; the left axial surface of the upper end cover facing the external environment is marked as surface 3, the right axial surface facing the upper air cavity inside the conductor cylinder is marked as surface 4, the through-hole area in the upper end cover is equivalently treated as a circular ring with the same radius, the inner diameter surface of the circular ring is marked as surface 6, and the outer diameter surface of the circular ring is marked as surface 5; the right axial surface of the lower end cover facing the external environment is marked as surface 2, the left axial surface facing the lower air cavity inside the conductor cylinder is marked as surface 12, and the inner surface facing the moving rod is marked as surface 18; to ensure the momentary correspondence of the eddy current losses of the magnetic group and the conductor cylinder in terms of spatial position, the inner surface of the conductor cylinder is divided into three parts, namely the inner surfaces 7 and 15 facing the upper and lower air cavities and the inner surface 21 at the air gap; the outer surface of the nut is marked as surface 11, and the left axial surface facing the upper air cavity is marked as surface 8; the left axial surface of the guide ring in the upper air cavity area is marked as surface 10, and the right axial surface facing the air gap is marked as surface 20; the right axial surface of the guide ring in the lower air cavity area is marked as surface 14, and the left axial surface facing the air gap is marked as surface 23; since the inner and outer diameters of the permanent magnet and the pole shoe are the same, their outer surfaces are represented by the same marked surface, that is, the outer surface facing the air gap is marked as surface 22; the left axial surface of the moving rod facing the upper air cavity is marked as surface 9, a part of the outer surface facing the lower air cavity is marked as surface 13, a part of the outer surface facing the lower end cover is marked as surface 17, and the part of the outer surface and the right axial surface facing the external environment are surface 19 and surface 16 respectively. The calculation method of the dimensionless number is as follows: Where, N u is the Nusselt number; R e is the Reynolds number; P r is the Prandtl number; G r is the Grashof number; L is the characteristic length; ρ is the fluid density; v is the fluid flow velocity; μ is the dynamic viscosity of the fluid; g is the acceleration due to gravity; β is the coefficient of volume expansion of the fluid; θ is the temperature difference between the fluid and the solid on the convective heat transfer surface; λ is the thermal conductivity; The convective heat transfer coefficients of each convective heat transfer surface are calculated as follows: Surface 1 is regarded as the natural convective heat transfer of a horizontally placed outer cylindrical wall surface, and the calculation method of its convective heat transfer coefficient is as follows: In the formula, D is the cylinder diameter, that is, the outer diameter of the back iron cylinder; Surfaces 2 and 3 are regarded as the natural convective heat transfer under a vertical wall surface, and their convective heat transfer coefficients are calculated as follows: Surface 19 is calculated using the classical heat dissipation formula, and the surface fluid velocity is the same as the velocity of the moving rod. The convective heat transfer coefficient is calculated as follows: where T f is the ambient temperature; Surfaces 4, 8 - 10, 12, 14, 16, 20, 23 are the forced convective heat transfer on a vertical flat plate, and their convective heat transfer coefficients can be solved according to the Nusselt number, that is, formula 57. The experimental correlations of the relevant Nusselt numbers are as follows: N u = 0.16R e 0.699 (65) Surfaces 5-7, 11, 13, 15, 17, 18, 21, 22 are concentric annular pipe flows, and the R e calculated value is less than 2300, so it is laminar flow. Therefore, the Nusselt number can be calculated according to Table 1 below, and the corresponding convective heat transfer coefficient can be calculated in combination with Equation 57; Table 1 Nusselt number selection table With the help of the lumped heat system module in the COMSOL simulation software, manually build the equivalent thermal network model of the eddy current damper according to the heat source, heat capacity, and thermal resistance solved by formulas 47 - 66, and the temperature rise of the permanent magnet and the conductor cylinder can be calculated.

5. A calculation system for the temperature rise of the permanent magnet and the conductor cylinder of an eddy current damper based on electromagnetic-temperature field coupling, characterized in that, Implement the calculation method for the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper based on electromagnetic - temperature field coupling described in any one of claims 1 - 6, and realize the calculation of the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper based on electromagnetic - temperature field coupling. Execute steps 1 to 3 in three modules respectively.

6. A computer device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, it implements the calculation method for the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper based on electromagnetic-temperature field coupling according to any one of claims 1-6, and realizes the calculation of the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper based on electromagnetic-temperature field coupling.

7. A computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the calculation method for the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper based on electromagnetic-temperature field coupling according to any one of claims 1-6, and realizes the calculation of the temperature rise of the permanent magnet and the conductor cylinder of the eddy current damper based on electromagnetic-temperature field coupling.

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