A method for calculating braking distance of an eddy current brake

Abstract

The application provides a braking distance calculation method of an eddy current brake, and belongs to the field of eddy current brake design. The method solves the problem that a traditional analytic model cannot accurately calculate train braking distance. The method comprises the following steps: an analytic model of an eddy current brake is established, and a braking force characteristic curve of the eddy current brake is calculated; based on the primary length of the eddy current brake and the initial speed of a train, a braking dynamics equation in the process that a primary of the eddy current brake enters a secondary conductor plate is obtained, and the initial speed at the time of entering a complete braking process is calculated; the braking distance of the train under the action of the eddy current brake in the complete braking process is calculated; and the braking distance in the entering process and the braking distance in the complete braking process are added to obtain the total braking distance. The method is mainly used in the field of high-speed train braking.

Description

Technical Field

[0001] This invention belongs to the field of eddy current brake design, and in particular relates to a method for calculating the braking distance of an eddy current brake. Background Technology

[0002] Eddy current brakes, as a non-contact braking device, have broad application prospects in high-speed train braking. Their basic structure includes a primary excitation source and a secondary conductor. Eddy currents are generated through the relative motion between the two, thus forming braking force. Compared with traditional viscous or viscoelastic dampers, eddy current brakes have no mechanical contact between the primary and secondary conductors during braking, which does not affect the system's dynamic response or material properties. They also offer significant advantages such as low noise, convenient maintenance, long lifespan, flexible control, high reliability, and environmental friendliness. In practical applications, the primary conductor of the eddy current brake is typically installed on the train, while the secondary conductor is laid on the track. When the train moves, the primary and secondary conductors undergo relative displacement, generating braking force to achieve deceleration. This characteristic makes eddy current brakes particularly suitable for scenarios requiring rapid and smooth braking, such as high-speed railways or maglev systems.

[0003] Currently, analytical modeling research on eddy current brakes is quite common. Its core is based on establishing a hierarchical model using Maxwell's equations, deriving the braking force characteristic curve by calculating the general solution and boundary conditions of the vector magnetic potential, and further using it to predict braking distance. This type of analytical model can provide theoretical guidance for the design and optimization of eddy current brakes. However, existing analytical models typically assume that the primary winding of the eddy current brake is always fully covered by the secondary conductor plate. This may hold true in rail trains because the rails can serve as continuous secondary conductors, but it has significant limitations in some practical applications such as maglev trains. For cost reasons, the secondary conductor plate of maglev systems is often only laid in specific sections such as stations and emergency stopping areas, rather than covering the entire track. Therefore, the primary winding of the eddy current brake undergoes an "entry" process in the initial braking phase: initially, the primary winding is completely uncovered by the secondary conductor and does not generate braking force; as the train moves forward, the primary winding is gradually partially covered by the secondary conductor, and the braking force increases nonlinearly from zero; only after the primary winding is completely covered by the secondary conductor does the braking force reach a stable state and change with speed.

[0004] The deficiency in existing technologies lies in their analytical models' failure to consider the impact of the aforementioned "entry" process on braking force. For example, in traditional methods, braking force calculations are directly based on the full coverage assumption, neglecting the gradual change in braking force during the initial partial coverage phase. This leads to significant discrepancies between the calculated braking distance and the actual value. Specifically, during the "entry" process, the braking force does not reach its maximum instantaneous value but increases gradually with time and displacement, and may even experience slight acceleration in the initial stage due to the attraction between the back iron and the primary iron core. Existing models cannot capture this nonlinear dynamic, thus overestimating or underestimating the actual value when calculating the braking distance. Taking maglev trains as an example, if only an analytical model with the full coverage assumption is used, the calculation error of the braking distance may be as high as 10% or more, which not only affects the control accuracy of the braking system but may also pose a risk to the safe operation of the train. Summary of the Invention

[0005] In view of this, the present invention aims to propose a method for calculating the braking distance of an eddy current brake, so as to solve the problem that traditional analytical models cannot accurately calculate the braking distance of trains.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a method for calculating the braking distance of an eddy current brake, the method comprising: Step S1: Establish an analytical model of the eddy current brake and calculate the braking force characteristic curve of the eddy current brake; Step S2: Based on the primary length of the eddy current brake and the initial velocity of the train, obtain the braking dynamics equation of the primary eddy current brake entering the secondary conductor plate, and calculate the initial velocity at the moment of entering the full braking process. Step S3: Calculate the braking distance of the train under the action of the eddy current brake during the full braking process; Step S4: Add the braking distance of the entry process to the braking distance of the complete braking process to obtain the total braking distance.

[0007] Furthermore, a preferred embodiment is proposed, wherein step S1 includes: Based on Maxwell's equations, a layered model of the eddy current brake is constructed, which includes a primary core region, a permanent magnet region, an air gap region, a conductor plate region, and a back iron region. List the general solution form of the vector magnetic potential of each region, and solve for the undetermined coefficients by using boundary conditions; Calculation of eddy current braking force based on Maxwell's stress equation The formula is:

[0008] in, l For the primary core width, p For extreme logarithms, air permeability, For polar moments, and This represents the magnetic flux density component in the air gap region.

[0009] Furthermore, a preferred approach is proposed, wherein the general solution of the vector magnetic potential of each region in the hierarchical model is as follows: Primary core area:

[0010]

[0011] in, It is the vector magnetic potential in the primary iron core. C 1 and D 1 is an undetermined coefficient. k It is the space wavenumber. for y Axis coordinate values; Permanent magnet region:

[0012] in, It is the vector magnetic potential in the permanent magnet region. and These are undetermined coefficients. B ry For the remanence of permanent magnets x The fundamental amplitude of the directional distribution waveform; Air gap region:

[0013] in, It is the vector magnetic potential in the air gap region. and These are undetermined coefficients; Conductor plate area:

[0014]

[0015]

[0016] in, It is the vector magnetic potential in the conductor plate region. and For undetermined coefficients, μ c The relative permeability of the conductor plate, σ c The conductivity of the conductor plate, v The relative velocity between the primary and secondary windings of the eddy current brake. Let j be the power value of the general solution equation, and j be the imaginary unit. An angle is a complex vector. Back iron area:

[0017] in, It is the vector magnetic potential in the back iron region. and These are undetermined coefficients.

[0018] Furthermore, a preferred embodiment is proposed, wherein the boundary conditions include: The magnetic flux density and magnetic field strength at the interface between the primary iron core and the permanent magnet are continuous; The magnetic flux density and magnetic field strength at the interface between the permanent magnet and the air gap are continuous; The magnetic flux density and magnetic field strength at the junction of the air gap and the conductor plate are continuous; The magnetic flux density and magnetic field strength at the junction of the conductor plate and the back iron are continuous; The magnetic flux density on the upper surface of the primary core and the lower surface of the back iron is zero.

[0019] Furthermore, a preferred embodiment is proposed, wherein the braking dynamics equation for the entry process is based on the assumption that the braking force increases linearly with time, and is expressed as:

[0020] in, a 1 refers to the train's deceleration during entry. v 0 is the initial velocity of the train. m It's about train quality. t max This is the moment when the primary core is completely inserted into the secondary conductor plate. F max The braking force amplitude is, v max For speed.

[0021] Furthermore, a preferred method is proposed, wherein the train decelerates during the entry process. a The calculation of 1 introduces a correction factor. β To compensate for the attraction effect between the back iron and the primary iron core, the formula is: ,

[0022] Where b is the linear slope of braking force versus speed. This is the equivalent slope.

[0023] Furthermore, a preferred method is proposed, in which the braking force during the complete braking process is obtained by polynomial fitting of the velocity function:

[0024] in, , , , and represents the coefficients of polynomials of various orders.

[0025] Furthermore, a preferred method is proposed, in which the braking distance of the complete braking process is calculated by integration: .

[0026] Based on the same inventive concept, the present invention also proposes a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the processor runs the computer program stored in the memory, the processor executes a braking distance calculation method for an eddy current brake according to any of the preceding claims.

[0027] Based on the same inventive concept, the present invention also proposes a computer-readable storage medium storing a computer program, which, when executed by a processor, performs the steps of a braking distance calculation method for an eddy current brake as described in any of the above-mentioned embodiments.

[0028] Compared with the prior art, the beneficial effects of the present invention are: This invention breaks away from the simplistic approach of traditional analytical models that treat the braking process as a single steady state. By constructing a segmented, coupled dynamic analysis framework, it decomposes the braking distance calculation into two stages: the entry process and the full braking process. It also introduces the synergistic effect of two types of techniques: first, a precise quantification method for braking force based on a layered electromagnetic field model; and second, a transient dynamic correction mechanism for non-full-coverage scenarios. These two techniques are not simply superimposed but form an organic whole through parameter transfer and coupling with physical effects. For example, the braking force slope parameter output by the analytical model is dynamically applied to the dynamic equations of the entry stage, while the initial velocity calculated in this stage serves as the input condition for the integral calculation in the full braking stage, forming a closed-loop feedback that collectively improves accuracy.

[0029] Traditional methods rely solely on Maxwell's equations to establish steady-state braking force models, assuming the primary conductor is always fully covered by the secondary conductor. This fails to reflect the gradual braking force characteristics caused by the segmented laying of the secondary conductor plate in scenarios such as maglev trains. This invention identifies the start and end points of the entry phase—the moment when the primary conductor is fully covered—by analyzing the real-time relationship between the primary conductor length and train speed. Based on the linear growth assumption, a time-domain braking force variation model is established, addressing the theoretical blind spot that traditional methods cannot handle in partially covered phases. An empirical coefficient β is introduced into the entry phase dynamics model to correct the abnormally positive braking force caused by the attraction between the back iron and the primary core—i.e., the transient acceleration effect—and avoid its interference with deceleration accumulation. This compensation mechanism, combined with the linear assumption, simplifies calculations while preserving key physical effects. The complex braking force-velocity relationship output by the analytical model is transformed into a polynomial function, preserving the accuracy of electromagnetic field theory while achieving a continuous description of the variable deceleration process through integral operations, avoiding the error accumulation of traditional piecewise approximation methods.

[0030] This invention significantly improves the accuracy of braking distance prediction without substantially increasing computational complexity. Data shows that, under the same number of pole pairs and initial velocity, the results of this invention are in high agreement with the finite element method. For example, with 3 pole pairs and a velocity of 1 m / s, the error between the proposed result (522.4 mm) and the finite element result (523.3 mm) is only 0.17%, while the traditional method, which ignores the entry process, has an error exceeding 10%. This effect verifies the effectiveness of the synergy between the analytical model, dynamic correction, and integral calculation, highlighting the technical superiority of this invention. Attached Figure Description

[0031] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a flowchart of a braking distance calculation method for an eddy current brake according to the present invention; Figure 2 This is a schematic diagram of the basic structure of the eddy current brake described in this invention; Figure 3 This is a schematic diagram of a layered model of the eddy current brake described in this invention; Figure 4 This is a graph showing the change in braking force during the braking process described in this invention. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other, and the described embodiments are only some embodiments of the present invention, not all embodiments.

[0033] Implementation Method 1, see Figure 1 This embodiment describes a method for calculating the braking distance of an eddy current brake. The method includes: Step S1: Establish an analytical model of the eddy current brake and calculate the braking force characteristic curve of the eddy current brake; Step S2: Based on the primary length of the eddy current brake and the initial velocity of the train, obtain the braking dynamics equation of the primary eddy current brake entering the secondary conductor plate, and calculate the initial velocity at the moment of entering the full braking process. Step S3: Calculate the braking distance of the train under the action of the eddy current brake during the full braking process; Step S4: Add the braking distance of the entry process to the braking distance of the complete braking process to obtain the total braking distance.

[0034] Step S1 in this embodiment includes: Based on Maxwell's equations, a layered model of the eddy current brake is constructed, which includes a primary core region, a permanent magnet region, an air gap region, a conductor plate region, and a back iron region. List the general solution form of the vector magnetic potential of each region, and solve for the undetermined coefficients by using boundary conditions; Calculation of eddy current braking force based on Maxwell's stress equation The formula is:

[0035] in, l For the primary core width, p For extreme logarithms, air permeability, For polar moments, and This represents the magnetic flux density component in the air gap region.

[0036] By using a hierarchical model based on Maxwell's equations and Maxwell's stress equations, the braking force generated by the air gap magnetic field is quantitatively calculated, avoiding errors caused by empirical formulas or approximation methods.

[0037] The general solution form of the vector magnetic potential of each region in the layered model described in this embodiment is: Primary core area:

[0038]

[0039] in, It is the vector magnetic potential in the primary iron core. C 1 and D 1 is an undetermined coefficient.k It is the space wavenumber. for y Axis coordinate values; Permanent magnet region:

[0040] in, It is the vector magnetic potential in the permanent magnet region. and These are undetermined coefficients. B ry For the remanence of permanent magnets x The fundamental amplitude of the directional distribution waveform; Air gap region:

[0041] in, It is the vector magnetic potential in the air gap region. and These are undetermined coefficients; Conductor plate area:

[0042]

[0043]

[0044] in, It is the vector magnetic potential in the conductor plate region. and These are undetermined coefficients. μ c The relative permeability of the conductor plate, σ c The conductivity of the conductor plate, v The relative velocity between the primary and secondary windings of the eddy current brake. Let j be the power value of the general solution equation, and j be the imaginary unit. An angle is a complex vector. Back iron area:

[0045] in, It is the vector magnetic potential in the back iron region. and These are undetermined coefficients.

[0046] Through mathematical expression, the electromagnetic field distribution along the entire path from the permanent magnet to the back iron is characterized. In particular, the introduction of complex parameters of relative velocity and material properties in the conductor plate region effectively reflects the frequency dependence of the eddy current effect. This general solution form ensures that the model can adapt to different speed conditions and material parameters, improving the universality of the method and the computational stability under complex electromagnetic-motion coupling fields.

[0047] The boundary conditions described in this embodiment include: The magnetic flux density and magnetic field strength at the interface between the primary iron core and the permanent magnet are continuous; The magnetic flux density and magnetic field strength at the interface between the permanent magnet and the air gap are continuous; The magnetic flux density and magnetic field strength at the junction of the air gap and the conductor plate are continuous; The magnetic flux density and magnetic field strength at the junction of the conductor plate and the back iron are continuous; The magnetic flux density on the upper surface of the primary core and the lower surface of the back iron is zero.

[0048] By setting continuous boundary conditions for magnetic flux density and magnetic field strength, the physical self-consistency and closure of the entire electromagnetic field model are ensured, effectively eliminating model solution errors caused by incomplete boundary assumptions and improving the reliability of braking force calculation.

[0049] The braking dynamics equation for the entry process described in this embodiment is based on the assumption that the braking force increases linearly with time, and is expressed as:

[0050] in, a 1 refers to the train's deceleration during entry. v 0 is the initial velocity of the train. m It's about train quality. t max This is the moment when the primary core is completely inserted into the secondary conductor plate. F max For braking force amplitude, v max For speed.

[0051] A dynamic equation based on the linear assumption is proposed for the "entry" process. This simplification greatly reduces the mathematical complexity and computational resource consumption of the dynamic analysis in this stage without losing the braking force growth.

[0052] The train deceleration during the entry process described in this embodiment a The calculation of 1 introduces a correction factor. β To compensate for the attraction effect between the back iron and the primary core, the formula is: ,

[0053] Where b is the linear slope of braking force versus speed. This is the equivalent slope.

[0054] In this embodiment, the braking force during the full braking process is obtained by fitting the velocity function using a polynomial:

[0055] in, , , , and represents the coefficients of polynomials of various orders.

[0056] In this embodiment, the braking distance during the full braking process is calculated by integration: .

[0057] Implementation Method 2, see below Figures 2 to 4 This embodiment describes a complete implementation of the braking distance calculation method for an eddy current brake described in Embodiment 1. Specifically: A method for calculating the braking distance of an eddy current brake, the method comprising the following steps: Step 1: Establish an analytical model of the eddy current brake and calculate the braking force characteristic curve of the eddy current brake; The basic structure of an eddy current brake is as follows: Figure 2 As shown, its hierarchical model is as follows: Figure 3 As shown, the layered model includes a primary core region, a permanent magnet region, an air gap region, a conductor plate region, and a back iron region; Based on Maxwell's equations, the general solution for the vector magnetic potential in each region is as follows: Area 1: Primary Iron Core (1) (2) In the formula, A 1 represents the vector magnetic potential in region 1 (primary core). C 1 and D 1 represents the undetermined coefficients. k It is the space wavenumber. τ It is the polar moment.

[0058] Area 2: Permanent Magnet (3) In the formula, B ry For the remanence of permanent magnets x The fundamental amplitude of the directional distribution waveform.

[0059] Region 3: Air gap (4) Area 4: Conductor Plate (5) (6) (7) In the formula, μ c The relative permeability of the conductor plate, μ 0 represents the permeability of air. σ c The conductivity of the conductor plate, v The relative velocity between the primary and secondary windings of the eddy current brake.

[0060] Area 5: Back Iron (8) according to Figure 2 The hierarchical model in the text can be defined by the following boundary conditions: (9) (10) (11) (12) (13) (14) In the formula, g The length of the air gap. h m Length is the magnetization direction of the permanent magnet. h j Primary core thickness, u r The relative permeability of the primary core and the back iron is denoted as . u m and u c These are the relative permeabilities of the permanent magnet and the conductor plate, respectively. h b The thickness of the backing iron.

[0061] Using the above boundary conditions, all undetermined coefficients can be obtained. After solving for the undetermined coefficients, the eddy current braking force can be calculated using Maxwell's stress equations, as shown in the following formula: (15) In the formula, l For the primary core width, p It is an extreme logarithm.

[0062] Step 2: Obtain the braking dynamics equations during the "entry" process using the initial length of the eddy current brake and the initial velocity of the train, and calculate the initial velocity at the moment of entering the full braking process. The entire braking process of the eddy current brake is analyzed based on the finite element results, such as... Figure 4 As shown, the braking force gradually increases during the "entry" process; it reaches its maximum after the primary core has completely entered the secondary conductor plate; subsequently, as the speed decreases, the braking force gradually decreases to zero.

[0063] Assuming the braking force increases linearly with time during the "entry" process, and setting the moment when the primary core is fully inserted into the secondary conductor plate as... t max Braking force amplitude is F max The speed is v max Therefore, the following dynamic equations can be derived: (16) (17) In the formula, a 1 represents the train's deceleration during the "entry" process. v 0 is the initial velocity of the train. m Regarding the train's mass, since the "entry" process is brief, we assume the train's braking force and speed have a linear relationship, and its slope is... b . b The amplitude can be calculated using formula (15). Figure 4 As can be seen, at the very beginning of the "entry" process, the braking force is positive, which is equivalent to applying a pulling force to the train, causing it to accelerate. This is due to the attraction between the back iron and the primary iron core. To account for this phenomenon, a coefficient is introduced here. β .

[0064] (18) Based on experience β It is 0.7, and will b Substitute it into (17).

[0065] The calculation can be performed using formulas (16) and (17). v max , that is, the initial velocity at the moment of entering the full braking process.

[0066] Step 3: Calculate the braking distance of the train under the action of the eddy current brake during the full braking process.

[0067] During full braking, the change in braking force of the eddy current brake over time can be calculated using formula (15). To facilitate the presentation of the train's dynamic equations, formula (15) is fitted with a polynomial to obtain the curve of braking force versus speed.

[0068] (19) (20) (twenty one) Step 4: Add the braking distances during the train's "entry" process and the full braking process to obtain the final train braking distance.

[0069] (twenty two) The accuracy of the calculated braking distance was verified using the finite element method.

[0070] The parameter settings for the eddy current brake are shown in Table 1.

[0071] Table 1 Design parameters of eddy current brake

[0072] Table 2 presents the calculation results of braking distance using the method proposed in this invention, the finite element method, and without considering the "entry" process. It can be seen that the method proposed in this invention significantly improves the accuracy of braking force calculation, confirming the effectiveness and accuracy of the proposed method.

[0073] Table 2 Braking distance calculation results

[0074] Implementation Method 3: A computer device according to this implementation method includes a memory and a processor. The memory stores a computer program. When the processor runs the computer program stored in the memory, the processor executes a braking distance calculation method for an eddy current brake according to any one of Implementation Method 1 to Implementation Method 2.

[0075] Implementation Method 4: A computer-readable storage medium according to this implementation method stores a computer program, which, when executed by a processor, performs the steps of a braking distance calculation method for an eddy current brake as described in any one of Implementation Methods 1 to 2.

[0076] Those skilled in the art will understand that embodiments of this disclosure can be provided as methods, systems, or computer program products. Therefore, this disclosure can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this disclosure can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0077] This disclosure is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create a machine for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 The computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0078] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure and not to limit its protection scope. Although this disclosure has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading this disclosure, they can still make various changes, modifications or equivalent substitutions to the specific implementation of the invention, but these changes, modifications or equivalent substitutions are all within the protection scope of the published pending claims.

Claims

1. A method for calculating the braking distance of an eddy current brake, characterized in that, The method includes: Step S1: Establish an analytical model of the eddy current brake and calculate the braking force characteristic curve of the eddy current brake; Step S2: Based on the primary length of the eddy current brake and the initial velocity of the train, obtain the braking dynamics equation of the primary eddy current brake entering the secondary conductor plate, and calculate the initial velocity at the moment of entering the full braking process. Step S3: Calculate the braking distance of the train under the action of the eddy current brake during the full braking process; Step S4: Add the braking distance of the entry process to the braking distance of the complete braking process to obtain the total braking distance.

2. The method for calculating the braking distance of an eddy current brake according to claim 1, characterized in that, Step S1 includes: Based on Maxwell's equations, a layered model of the eddy current brake is constructed, which includes a primary core region, a permanent magnet region, an air gap region, a conductor plate region, and a back iron region. List the general solution form of the vector magnetic potential of each region, and solve for the undetermined coefficients by using boundary conditions; Calculation of eddy current braking force based on Maxwell's stress equation The formula is: in, l For the primary core width, p For extreme logarithms, air permeability, For polar moments, and This represents the magnetic flux density component in the air gap region.

3. The method for calculating the braking distance of an eddy current brake according to claim 2, characterized in that, The general solution form of the vector magnetic potential of each region in the layered model is: Primary core area: in, It is the vector magnetic potential in the primary iron core. C 1 and D 1 is an undetermined coefficient. k It is the space wavenumber. for y Axis coordinate values; Permanent magnet region: in, It is the vector magnetic potential in the permanent magnet region. and These are undetermined coefficients. B ry For the remanence of permanent magnets x The fundamental amplitude of the directional distribution waveform; Air gap region: in, It is the vector magnetic potential in the air gap region. and These are undetermined coefficients; Conductor plate area: in, It is the vector magnetic potential in the conductor plate region. and These are undetermined coefficients. μ c The relative permeability of the conductor plate, σ c The conductivity of the conductor plate, v The relative velocity between the primary and secondary windings of the eddy current brake. Let j be the power value of the general solution equation, and j be the imaginary unit. An angle is a complex vector. Back iron area: in, It is the vector magnetic potential in the back iron region. and These are undetermined coefficients.

4. The method for calculating the braking distance of an eddy current brake according to claim 2, characterized in that, The boundary conditions include: The magnetic flux density and magnetic field strength at the interface between the primary iron core and the permanent magnet are continuous; The magnetic flux density and magnetic field strength at the interface between the permanent magnet and the air gap are continuous; The magnetic flux density and magnetic field strength at the junction of the air gap and the conductor plate are continuous; The magnetic flux density and magnetic field strength at the junction of the conductor plate and the back iron are continuous; The magnetic flux density on the upper surface of the primary core and the lower surface of the back iron is zero.

5. The method for calculating the braking distance of an eddy current brake according to claim 3, characterized in that, The braking dynamics equation for the entry process is based on the assumption that the braking force increases linearly with time, and is expressed as: in, a 1 refers to the train's deceleration during entry. v 0 is the initial velocity of the train. m It's about train quality. t max This is the moment when the primary core is completely inserted into the secondary conductor plate. F max For braking force amplitude, v max For speed.

6. The method for calculating the braking distance of an eddy current brake according to claim 5, characterized in that, The train deceleration during the entry process a The calculation of 1 introduces a correction factor. β To compensate for the attraction effect between the back iron and the primary iron core, the formula is: ， Where b is the linear slope of braking force versus speed. This is the equivalent slope.

7. The method for calculating the braking distance of an eddy current brake according to claim 5, characterized in that, The braking force during the complete braking process is obtained by fitting the velocity function using a polynomial: in, , , , and represents the coefficients of polynomials of various orders.

8. The method for calculating the braking distance of an eddy current brake according to claim 7, characterized in that, The braking distance during the complete braking process is calculated by integration: 。 9. A computer device, characterized in that: It includes a memory and a processor, wherein the memory stores a computer program, and when the processor runs the computer program stored in the memory, the processor executes a braking distance calculation method for an eddy current brake according to any one of claims 1-8.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, performs the steps of a braking distance calculation method for an eddy current brake as described in any one of claims 1-8.

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