High-speed built-in permanent magnet rotor design method, system and equipment based on stress analysis model

Abstract

The invention belongs to the field of rotor design, particularly relates to a high-speed built-in permanent magnet rotor design method, system and equipment based on a stress analysis model, and aims to solve the problem that the structural strength and electromagnetic performance of a high-speed built-in permanent magnet synchronous motor rotor are difficult to collaboratively optimize in the prior art. The method comprises the steps of determining the axial length and the outer diameter of a rotor according to a motor torque demand and an assembly space, and ensuring that a critical rotating speed is higher than a target limit value through dynamic verification; decomposing the rotor into pole shoe, permanent magnet and slotting areas, calculating centrifugal force in different areas, and superposing to obtain a total load; establishing a corresponding stress boundary equation set for a non-magnetic bridge, single / combined magnetic bridge or sheath composite structure; and solving the equation set based on the target rotating speed, and synchronously optimizing the sheath thickness, the magnetic bridge width and the interference magnitude parameter by using the intersection point of the isorotation speed line and the electromagnetic-mechanical characteristic curve. The problem of contradiction between size parameters and performance in traditional design is solved, and calculation efficiency and precision are both considered.

Description

Technical Field

[0001] The present invention belongs to the field of rotor design, and in particular relates to a high-speed built-in permanent magnet rotor design method, system and equipment based on a stress analysis model. Background Art

[0002] In today's world of energy constraints and prominent environmental issues, energy conservation, emission reduction, and noise reduction have become key goals for future aircraft. Aviation electrification is one of the primary pathways to improving aircraft energy efficiency and reducing carbon emissions, with the development of multi-electric and all-electric aircraft a key trend in the aviation industry. Aviation motor systems are a crucial foundation for the electrification of aircraft. The use of high-speed motors allows for direct connection to higher-speed prime movers, simplifying or eliminating the need for large and complex mechanical transmissions, further improving system energy efficiency and power density.

[0003] High-speed interior permanent magnet synchronous motors (HIPMSMs) have high torque density and a wide constant power operating range due to their asymmetric d / q-axis magnetic circuits and a certain saliency, making them promising for aviation applications. However, the high surface linear velocity of the rotor, resulting in high centrifugal forces, and the structural integrity of the rotor have hindered their development.

[0004] High-speed interior permanent magnet synchronous motors (IPMS) utilize a magnetic bridge or a sheath wrapped around the rotor surface to enhance structural strength. The dimensions of the bridge and sheath are closely related to the maximum speed. Too small a size can compromise structural integrity. Furthermore, the bridge and sheath significantly impact the electromagnetic performance of high-speed permanent magnet synchronous motors, while oversizing them can degrade performance. Therefore, appropriate structural parameters significantly impact both the electromagnetic performance and structural strength of high-speed permanent magnet synchronous motors.

[0005] Analyzing rotor structural strength is a crucial step in the design of high-speed permanent magnet synchronous motors. Common analysis methods include the finite element method (FEM) and analytical methods. While FEM is not restricted by geometric shape and produces accurate results, it is computationally demanding, time-consuming, and inefficient. Analytical models, on the other hand, offer rapid calculation speed and a reasonable level of accuracy, making them suitable for rapid rotor strength analysis during the initial design phase. Establishing an analytical stress model for high-speed interior permanent magnet rotors, based on which rotor structural parameters are calculated to meet operating speed limits, enables rapid design of high-speed interior permanent magnet rotors.

[0006] Based on this, the present invention proposes a high-speed internal permanent magnet rotor design method, system and equipment based on a stress analysis model. Summary of the Invention

[0007] In order to solve the above-mentioned problem in the prior art, that is, the problem that the structural strength and electromagnetic performance of the high-speed built-in permanent magnet synchronous motor rotor are difficult to coordinately optimize in the prior art, the present invention provides a high-speed built-in permanent magnet rotor design method, system and equipment based on a stress analysis model.

[0008] In a first aspect of the present invention, a method for designing a high-speed interior permanent magnet rotor based on a stress analysis model is proposed. The method comprises:

[0009] Based on the torque requirements and assembly space constraints of the high-speed permanent magnet synchronous motor, the rotor axial length and outer diameter are calculated, and the rotor dynamic characteristics are verified until the critical speed is higher than the target limit speed;

[0010] The rotor is divided into pole shoes, permanent magnets and slotted areas, the centrifugal force of each area is calculated separately, and the total centrifugal force of the rotor is obtained by adding them together;

[0011] Establishing a corresponding set of stress boundary condition equations according to the rotor structure type and the total centrifugal force of the rotor, wherein the rotor structure includes any one of a structure without a magnetic bridge, a structure with only an annular magnetic bridge, a structure with only a normal magnetic bridge, a structure with a combination of a sheath and an annular magnetic bridge, and a structure with a combination of a sheath and a normal magnetic bridge;

[0012] According to the target limiting speed, the stress boundary condition equations are solved, and the optimized values ​​of the sheath thickness, magnetic bridge width and interference are determined through the intersection of the constant speed line and the relationship curve to complete the rotor parameter design.

[0013] Furthermore, the centrifugal force of each region is as follows:

[0014] The pole shoe is decomposed into an annular region, an arcuate region and a trapezoidal sub-region. The pole shoe infinitesimal element is selected and the centrifugal forces of the annular region, the arcuate region and the trapezoidal sub-region are calculated based on the core material density and the rotational angular velocity. The centrifugal forces are then added together as the centrifugal forces of the pole shoe region.

[0015] The mass of the permanent magnet is equivalent to the center of mass position, and the equivalent centrifugal force component is calculated based on the material density and cross-sectional area of ​​the permanent magnet as the permanent magnet centrifugal force;

[0016] The slotted area is equivalent to negative mass, and the centrifugal force in the slotted area is calculated based on the hollowed area and the rotation radius.

[0017] Furthermore, the corresponding stress boundary condition equations are established based on the non-magnetic bridge structure, and the method is as follows:

[0018]

[0019] F is the total centrifugal force of the rotor, R ou is the outer radius of the sheath, R o is the outer radius of the core, R sleis the sheath thickness, R is the radius, σ rs is the sheath radial stress, σ θs is the sheath tangential stress, σ smax is the maximum allowable stress of carbon fiber material, L e is the axial length of the rotor, and α is the angle between the vertices of the permanent magnets on both sides and the center of the circle.

[0020] Furthermore, the corresponding stress boundary condition equations are established based on the annular magnetic bridge structure only, and the method is as follows:

[0021]

[0022] Among them, R i is the inner radius of the annular magnetic bridge, d ou is the thickness of the annular magnetic bridge, R o is the outer radius of the core, σ rg is the radial stress of the magnetic bridge, R is the radius, σ rθ is the tangential stress of the magnetic bridge, σ gmax is the maximum allowable stress of silicon steel sheet material, and F is the total centrifugal force of the rotor.

[0023] Furthermore, the corresponding stress boundary condition equations are established based on the normal magnetic bridge structure only, and the method is as follows:

[0024] L e d in σ r =F;

[0025] Among them, d in Normal magnetic bridge width, σ r Normal magnetic bridge stress, L e is the axial length of the rotor, and F is the total centrifugal force of the rotor.

[0026] Furthermore, the corresponding stress boundary condition equations are established based on the combined structure of the sheath and the annular magnetic bridge. The method is as follows:

[0027]

[0028] Among them, R ou is the outer radius of the sheath, R o is the outer radius of the core, R sle is the sheath thickness, R is the radius, R i is the inner radius of the annular magnetic bridge, d ou is the thickness of the annular magnetic bridge, R o is the outer radius of the core, σ rs is the sheath radial stress, σ θs is the sheath tangential stress, σ θg is the tangential stress of silicon steel sheet material, σ gmax is the maximum allowable stress of silicon steel sheet material, σsmax is the maximum allowable stress of carbon fiber material, F is the total centrifugal force of the rotor, L e is the axial length of the rotor, α is the angle between the vertices of the permanent magnets on both sides and the center of the circle, σ rg is the radial stress of the magnetic bridge.

[0029] Furthermore, the corresponding stress boundary condition equations are established based on the combined structure of the sheath and the normal magnetic bridge. The method is as follows:

[0030]

[0031] Among them, R ou is the outer radius of the sheath, R o is the outer radius of the core, R sle is the sheath thickness, R is the radius, σ θs is the sheath tangential stress, σ rs is the sheath radial stress, L e is the axial length of the rotor, σ gmax is the maximum allowable stress of silicon steel sheet material, F is the total centrifugal force of the rotor, d in Normal magnetic bridge width.

[0032] A second aspect of the present invention provides a high-speed interior permanent magnet rotor design system based on a stress analysis model. The system comprises:

[0033] a rotor axial length and outer diameter calculation and verification module configured to calculate the rotor axial length and outer diameter based on the torque requirement and assembly space constraints of the high-speed permanent magnet synchronous motor, and to verify the rotor dynamic characteristics until the critical speed is higher than the target limit speed;

[0034] A total centrifugal force calculation module is configured to divide the rotor into pole shoes, permanent magnets, and slotted areas, calculate the centrifugal force of each area separately, and add them together to obtain the total centrifugal force of the rotor;

[0035] a stress boundary condition equation group construction module configured to establish a corresponding stress boundary condition equation group according to a rotor structure type in combination with a total centrifugal force of the rotor, wherein the rotor structure includes any one of a structure without a magnetic bridge, a structure with only an annular magnetic bridge, a structure with only a normal magnetic bridge, a structure with a combination of a sheath and an annular magnetic bridge, and a structure with a combination of a sheath and a normal magnetic bridge;

[0036] The rotor parameter design module is configured to solve the stress boundary condition equations according to the target limit speed, determine the optimized values ​​of the sheath thickness, magnetic bridge width and interference through the intersection of the constant speed line and the relationship curve, and complete the rotor parameter design.

[0037] A third aspect of the present invention provides an electronic device, comprising:

[0038] at least one processor; and

[0039] a memory communicatively connected to at least one of the processors; wherein,

[0040] The memory stores instructions that can be executed by the processor, and the instructions are used to be executed by the processor to implement the above-mentioned high-speed interior permanent magnet rotor design method based on the stress analysis model.

[0041] In a fourth aspect of the present invention, a computer-readable storage medium is proposed, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to be executed by the computer to implement the above-mentioned high-speed internal permanent magnet rotor design method based on the stress analysis model.

[0042] Beneficial effects of the present invention:

[0043] By establishing a stress analysis model covering key structural parameters such as the magnetic bridge and sleeve, and on the premise of meeting the critical speed constraint of the rotor dynamics, the optimal solution for the sleeve thickness, magnetic bridge width and interference fit is quickly determined based on the intersection of the constant speed line and the electromagnetic performance relationship curve. This not only ensures the structural integrity of the rotor under high-speed conditions, but also avoids problems such as permanent magnet magnetic circuit saturation and air gap magnetic field distortion caused by the excessive size of the magnetic bridge / sheath, thereby achieving a dynamic balance between electromagnetic performance and mechanical strength.

[0044] An analytical modeling method based on the regional centrifugal force superposition and stress boundary condition equations is adopted to replace the traditional iterative trial and error process relying on the finite element method, which significantly shortens the rotor parameter design cycle. At the same time, by introducing targeted boundary conditions for different rotor structure types (such as no magnetic bridge, sheath combined magnetic bridge, etc.), the model's adaptability to different topological structures is improved, ensuring the fit between the analytical results and the actual working conditions.

[0045] The parameter solution mechanism based on the stress analysis model can simultaneously optimize the mutually coupled mechanical parameters such as the sheath, magnetic bridge and interference fit, avoiding the performance degradation caused by isolated parameter adjustment in traditional step-by-step design. It is especially suitable for the compact rotor design requirements in high power density and high speed scenarios of aviation motors.

[0046] The proposed method is compatible with various rotor structure types (such as pure magnetic bridge, pure sheath or composite structure). By adjusting the boundary condition equations, it can adapt to different electromagnetic-mechanical constraint scenarios, providing theoretical support for the modular design and rapid iteration of high-speed built-in permanent magnet rotors. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Other features, objects and advantages of the present application will become more apparent upon reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0048] Figure 1 2. It is a schematic structural diagram of a high-speed internal permanent magnet rotor according to the first embodiment of the present invention;

[0049] Figure 2 1 is a schematic diagram of the pole piece area element in the first embodiment of the present invention;

[0050] Figure 3 1 is a schematic diagram of centrifugal force analysis of a permanent magnet in the first embodiment of the present invention;

[0051] Figure 4 2. This is a schematic structural diagram of a high-speed internal permanent magnet rotor without a magnetic bridge according to the first embodiment of the present invention;

[0052] Figure 5 Schematic diagram of the variation of the limiting speed of the bridgeless rotor in the first embodiment of the present invention;

[0053] Figure 6 This is a schematic diagram of the structure of a high-speed internal permanent magnet rotor with only annular magnetic bridges in the first embodiment of the present invention;

[0054] Figure 7 Schematic diagram of the variation of the limiting speed of the circumferential magnetic bridge rotor only in the first embodiment of the present invention;

[0055] Figure 8 This is a schematic diagram of the structure of a high-speed internal permanent magnet rotor with only a normal magnetic bridge in the first embodiment of the present invention;

[0056] Figure 9 Schematic diagram of the variation of the limit speed of the normal magnetic bridge rotor in the first embodiment of the present invention;

[0057] Figure 10 Schematic diagram of the structure of the permanent magnet rotor that cannot be built into the magnetic bridge at high speed in the first embodiment of the present invention;

[0058] Figure 11 Schematic diagram of the variation law of the rotor speed limit that cannot reach the magnetic bridge in the first embodiment of the present invention;

[0059] Figure 12 2. It is a schematic structural diagram of a high-speed internal permanent magnet rotor without annular magnetic bridge in the first embodiment of the present invention;

[0060] Figure 13 It is a schematic diagram of the variation law of the limiting speed of the rotor without annular magnetic bridge in the first embodiment of the present invention. DETAILED DESCRIPTION

[0061] The present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are intended only to illustrate the relevant invention and are not intended to limit the invention. It should also be noted that, for ease of description, only portions relevant to the relevant invention are shown in the accompanying drawings.

[0062] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0063] The first embodiment of the present invention provides a method for designing a high-speed interior permanent magnet rotor based on a stress analysis model, the method comprising:

[0064] Step S10, calculating the rotor axial length and outer diameter according to the torque requirement and assembly space constraint of the high-speed permanent magnet synchronous motor, and verifying the rotor dynamic characteristics until the critical speed is higher than the target limit speed;

[0065] Step S20, dividing the rotor into pole shoes, permanent magnets, and slotted areas, calculating the centrifugal force of each area separately, and adding them together to obtain the total centrifugal force of the rotor;

[0066] Step S30, establishing a corresponding stress boundary condition equation group according to the rotor structure type and the total centrifugal force of the rotor, wherein the rotor structure includes any one of a structure without a magnetic bridge, a structure with only a circumferential magnetic bridge, a structure with only a normal magnetic bridge, a structure with a combination of a sheath and a circumferential magnetic bridge, and a structure with a combination of a sheath and a normal magnetic bridge;

[0067] Step S40 , solving the stress boundary condition equations according to the target limit speed, determining the optimized values ​​of the sheath thickness, the magnetic bridge width and the interference through the intersection of the constant speed line and the relationship curve, and completing the rotor parameter design.

[0068] In order to more clearly illustrate the design method of a high-speed internal permanent magnet rotor based on a stress analysis model of the present invention, the following is combined with Figure 1 Each step in the embodiment of the present invention is described in detail, including step S10 to step S40, and each step is described in detail as follows:

[0069] Step S10, calculating the rotor axial length and outer diameter according to the torque requirement and assembly space constraint of the high-speed permanent magnet synchronous motor, and verifying the rotor dynamic characteristics until the critical speed is higher than the target limit speed;

[0070] In this embodiment, the rotor axial length and rotor outer diameter are designed based on the torque formula of the high-speed permanent magnet synchronous motor and the torque and assembly space requirements. The dynamic characteristics of the high-speed permanent magnet rotor are verified to calculate whether the critical speed meets the design requirements.

[0071] T=1.11εcosθk wd ηAB m D i 2 L e ;

[0072] Where, θ is the power factor angle, k wd is the winding coefficient, η is the motor efficiency, A is the line load density, which represents the number of ampere conductors per unit length of the armature circumference, and B m is the fundamental amplitude of magnetic flux density under rated working conditions. 1T is selected according to the saturation magnetic flux density of ferromagnetic materials. i is the inner diameter of the stator, L e is the effective axial length of the motor.

[0073] Step S20, dividing the rotor into pole shoes, permanent magnets, and slotted areas, calculating the centrifugal force of each area separately, and adding them together to obtain the total centrifugal force of the rotor;

[0074] The centrifugal force of each region is calculated as follows:

[0075] Select the pole shoe infinitesimal element and decompose it into an annular region, an arcuate region and a trapezoidal sub-region. Select the pole shoe infinitesimal element and calculate the centrifugal force of the annular region, the arcuate region and the trapezoidal sub-region based on the core material density and the rotation angular velocity, and add them together as the centrifugal force of the pole shoe region.

[0076] The mass of the permanent magnet is equivalent to the center of mass position, and the equivalent centrifugal force component is calculated based on the material density and cross-sectional area of ​​the permanent magnet as the permanent magnet centrifugal force;

[0077] The slotted area is equivalent to negative mass, and the centrifugal force in the slotted area is calculated based on the hollowed area and the rotation radius.

[0078] In this embodiment, the pole shoe is decomposed into an annular region, an arcuate region, and a trapezoidal sub-region. The pole shoe infinitesimal element is selected, and the centrifugal forces of the annular region, the arcuate region, and the trapezoidal sub-region are calculated based on the core material density and the rotational angular velocity. The centrifugal forces are then added together to form the centrifugal force of the pole shoe region. Specifically,

[0079] First, solve the centrifugal force of the rotor in the pole shoe area. Figure 2 As shown, let the density of the core material be ρ g , the motor axial length is L e , the infinitesimal mass dm is:

[0080] dm=ρ g L e ds=ρ g L e dxdy;

[0081] When the angular velocity of rotation is ω, the centrifugal force on the infinitesimal element is:

[0082]

[0083] according to Figure 1, the pole shoe is divided into an annular area G1, an arcuate area G2 and a trapezoidal area G3, and the centrifugal force in the y-axis direction acting on different areas of the pole shoe is calculated as shown in the formula, with different subscripts used to represent different areas of the pole shoe.

[0084]

[0085] Among them, b m is the length of the permanent magnet.

[0086] The centrifugal force in the rotor pole shoe area is F G :

[0087] F G =F G1 +F G2 +F G3 .

[0088] Among them, F G1 is the centrifugal force in the annular area, F G2 is the centrifugal force in the arcuate area, F G3 is the centrifugal force in the trapezoidal area.

[0089] In this embodiment, the mass of the permanent magnet is equivalent to the center of mass position, and the equivalent centrifugal force component is calculated based on the density and cross-sectional area of ​​the permanent magnet material as the permanent magnet centrifugal force;

[0090] The permanent magnets have a regular shape, so the equivalent center of mass method is used to solve for the centrifugal force. This method assigns the entire mass of the permanent magnets to the center of mass, and the centrifugal force is calculated from the centrifugal force acting at the center of mass. Based on the motor structure, the force acting on the permanent magnets is determined to be only the centrifugal force perpendicular to the length of the permanent magnets acting on the pole pieces, which contributes to the centrifugal force along the rotor's y-axis.

[0091] The coordinates of the permanent magnet's equivalent center of mass are (x m ,y m ), the density of permanent magnet material is ρ m , the cross-sectional area of ​​the permanent magnet is A m , then the centrifugal force F when the center of mass rotates at an angular velocity ω M for:

[0092]

[0093] In this embodiment, the slotted area is equivalent to negative mass for analysis. The area A of this part Δ and the radius of rotation r Δ As shown in the formula,

[0094]

[0095] Where y1 and y2 are the coordinates of the vertices of the hollowed-out part, and the centrifugal force F of the part when the rotation angular velocity is ω is calculated by the center of mass equivalent method. Δ for:

[0096] F Δ =-ρ Δ L e r Δ ω 2 A Δ ;

[0097] In summary, the centrifugal force F of the high-speed internal permanent magnet synchronous motor rotor is:

[0098] F=F G +F Mdy +F Δ .

[0099] Step S30, establishing a corresponding stress boundary condition equation group according to the rotor structure type and the total centrifugal force of the rotor, wherein the rotor structure includes any one of a structure without a magnetic bridge, a structure with only a circumferential magnetic bridge, a structure with only a normal magnetic bridge, a structure with a combination of a sheath and a circumferential magnetic bridge, and a structure with a combination of a sheath and a normal magnetic bridge;

[0100] In this embodiment, high-speed internal permanent magnet rotors are classified based on whether they use a magnetic bridge and a carbon fiber sheath, and the analysis methods are summarized for each. The magnetic bridge and sheath of the high-speed permanent magnet rotor can be equivalent to a uniformly stressed circular ring, so a thick-walled cylinder model can be used for calculation, and the stress satisfies:

[0101]

[0102]

[0103] Among them, σ r is the radial stress, σ θ is the tangential stress, E r is the elastic modulus of the material along the direction of the rotation radius, E θ is the tangential elastic modulus of the material, μ rθ and μ θr They represent the influence of radial strain on tangential strain and the influence of tangential strain on radial strain, respectively. ρ is the density of thick-walled cylinder material, r is the radius of calculation position, and k is the intermediate variable, which is defined as E θ With E r Take the square root of the ratio, C1 and C2 are the coefficients to be determined;

[0104] High-speed internal permanent magnet rotor structure without magnetic bridge Figure 4As shown in the figure, the centrifugal force of the rotor is borne only by the sleeve. The sleeve thickness and interference are designed so that the tangential stress on the inside reaches the maximum allowable stress of the carbon fiber material under extreme operating conditions. The outside of the sleeve is not subjected to compressive stress, and the centrifugal force of the rotor acts on the inside of the sleeve to generate radial stress. That is:

[0105]

[0106] Where F is the total centrifugal force of the rotor, R ou is the outer radius of the sheath, R o is the outer radius of the core, R sle is the sheath thickness, R is the radius, σ rs is the sheath radial stress, σ θs is the sheath tangential stress, σ smax is the maximum allowable stress of carbon fiber material, L e is the axial length of the rotor, α is the angle between the vertices of the permanent magnets on both sides and the center of the circle, and the above equations are solved to obtain the relationship between the sheath thickness and the limiting speed. The relationship curve is as follows: Figure 5 shown.

[0107] The high-speed internal permanent magnet rotor structure containing only annular magnetic bridges is as follows Figure 6 As shown in the figure, the centrifugal force of the rotor is borne by the annular magnetic bridge. The thickness of the magnetic bridge is designed so that the tangential stress on the inner side reaches the maximum allowable stress of the silicon steel sheet when running at the limit speed. The outer side of the magnetic bridge is not subjected to compressive stress. The centrifugal force of the rotor acts on the inner side of the magnetic bridge to generate radial stress, that is:

[0108]

[0109] Among them, R i is the inner radius of the annular magnetic bridge, d ou is the thickness of the annular magnetic bridge, R o is the outer radius of the core, σ rg is the radial stress of the magnetic bridge, R is the radius, σ rθ is the tangential stress of the magnetic bridge, σ gmax is the maximum allowable stress of silicon steel sheet material, F is the total centrifugal force of the rotor, solve the above equations to calculate the relationship between the motor limit speed and the magnetic bridge thickness, and draw the relationship curve as shown in Figure 7 shown.

[0110] High-speed internal permanent magnet rotor structure with only normal magnetic bridge Figure 8 As shown, the centrifugal force of the rotor acts on the normal magnetic bridge to generate tensile stress. The thickness of the magnetic bridge is designed so that the tensile stress reaches the maximum allowable tensile stress of the silicon steel sheet when running at the limit speed. The magnetic bridge stress and the rotor centrifugal force satisfy the formula, and the relationship between the magnetic bridge width and the limit speed is as follows: Figure 9 shown.

[0111] L a din σ r =F;

[0112] Among them, d in Normal magnetic bridge width, σ r Normal magnetic bridge stress, L e is the axial length of the rotor, and F is the total centrifugal force of the rotor.

[0113] The high-speed internal permanent magnet rotor that does not use a normal magnetic bridge uses a sleeve and an annular magnetic bridge to improve the structural strength. Figure 10 As shown, the centrifugal force of the rotor is shared by the sleeve and the annular magnetic bridge. The thickness and interference of the sleeve and magnetic bridge are designed so that the tangential stress on the inner side of the sleeve and the magnetic bridge reaches the maximum allowable tensile stress of the material during operation at the limit speed, the outer side of the sleeve is not subjected to radial stress, the sleeve and the annular magnetic bridge are in close contact, the compressive stress on the contact surface is equal, and the centrifugal force acts on the sleeve and the inner side of the normal magnetic bridge to generate compressive stress. Summarizing the above conditions, the formula is:

[0114]

[0115] Among them, R ou is the outer radius of the sheath, R o is the outer radius of the core, R sle is the sheath thickness, R is the radius, R i is the inner radius of the annular magnetic bridge, d ou is the thickness of the annular magnetic bridge, R o is the outer radius of the core, σ rs is the sheath radial stress, σ θs is the sheath tangential stress, σ θg is the tangential stress of silicon steel sheet material, σ gmax is the maximum allowable stress of silicon steel sheet material, σ smax is the maximum allowable stress of carbon fiber material, F is the total centrifugal force of the rotor, L e is the axial length of the rotor, α is the angle between the vertices of the permanent magnets on both sides and the center of the circle, σ rg is the radial stress of the magnetic bridge.

[0116] Solving the equations, we can get the relationship between the limiting speed, the sheath and the magnetic bridge thickness as follows: Figure 11 shown.

[0117] The high-speed internal permanent magnet rotor structure without the annular magnetic bridge is as follows: Figure 12 As shown, the centrifugal force of the rotor is shared by the sleeve and the normal magnetic bridge. The thickness of the sleeve and the magnetic bridge is designed so that the tangential stress on the inner side of the sleeve and the tensile stress on the normal magnetic bridge reach the maximum allowable value of the material when running at the limit speed, and the outer side of the sleeve is not subject to compressive stress. Combined with the force analysis, the following formula is obtained:

[0118]

[0119] Among them, R ou is the outer radius of the sheath, R o is the outer radius of the core, R sle is the sheath thickness, R is the radius, σ θs is the sheath tangential stress, σ rs is the sheath radial stress, L e is the axial length of the rotor, σ gmax is the maximum allowable stress of silicon steel sheet material, F is the total centrifugal force of the rotor, d in Normal magnetic bridge width.

[0120] Solving the above equations, we can get the relationship between the limiting speed, the sheath thickness and the magnetic bridge width as follows: Figure 13 shown.

[0121] Step S40 , solving the stress boundary condition equations according to the target limit speed, determining the optimized values ​​of the sheath thickness, the magnetic bridge width and the interference through the intersection of the constant speed line and the relationship curve, and completing the rotor parameter design.

[0122] In this embodiment, according to the desired high-speed permanent magnet rotor structure type and the target limit speed, the high-speed permanent magnet rotor structural parameters are designed directly based on the analysis results of step S30. The intersection of the constant speed line or constant speed surface and the relationship image is selected according to the relationship image. The structural parameters corresponding to the intersection are the design scheme that meets the structural integrity of the high-speed permanent magnet rotor.

[0123] Although the various steps in the above embodiment are described in the above-mentioned order, those skilled in the art will understand that in order to achieve the effect of this embodiment, different steps do not have to be executed in such an order. They can be executed simultaneously (in parallel) or in a reverse order. These simple changes are within the scope of protection of the present invention.

[0124] A second embodiment of the present invention provides a high-speed interior permanent magnet rotor design system based on a stress analysis model, based on a high-speed interior permanent magnet rotor design method based on a stress analysis model, and includes:

[0125] a rotor axial length and outer diameter calculation and verification module configured to calculate the rotor axial length and outer diameter based on the torque requirement and assembly space constraints of the high-speed permanent magnet synchronous motor, and to verify the rotor dynamic characteristics until the critical speed is higher than the target limit speed;

[0126] A total centrifugal force calculation module is configured to divide the rotor into pole shoes, permanent magnets, and slotted areas, calculate the centrifugal force of each area separately, and add them together to obtain the total centrifugal force of the rotor;

[0127] a stress boundary condition equation group construction module configured to establish a corresponding stress boundary condition equation group according to a rotor structure type in combination with a total centrifugal force of the rotor, wherein the rotor structure includes any one of a structure without a magnetic bridge, a structure with only an annular magnetic bridge, a structure with only a normal magnetic bridge, a structure with a combination of a sheath and an annular magnetic bridge, and a structure with a combination of a sheath and a normal magnetic bridge;

[0128] The rotor parameter design module is configured to solve the stress boundary condition equations based on the target limit speed, determine the optimized values ​​of the sheath thickness, magnetic bridge width, and interference fit through the intersection of the constant speed line and the relationship curve, and complete the rotor parameter design. Those skilled in the art will clearly understand that for the sake of convenience and brevity, the specific operating process and related description of the system described above can be referred to the corresponding process in the aforementioned method embodiment and will not be repeated here.

[0129] It should be noted that the above embodiment provides a high-speed internal permanent magnet rotor design system based on a stress analysis model, and only illustrates the division of the above functional modules. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the modules or steps in the embodiments of the present invention can be further decomposed or combined. For example, the modules in the above embodiments can be combined into one module or further divided into multiple sub-modules to complete all or part of the functions described above. The names of the modules and steps involved in the embodiments of the present invention are merely for the purpose of distinguishing the modules or steps and are not to be considered as improper limitations of the present invention.

[0130] An electronic device according to a third embodiment of the present invention includes:

[0131] at least one processor; and

[0132] a memory communicatively connected to at least one of the processors; wherein,

[0133] The memory stores instructions that can be executed by the processor, and the instructions are used to be executed by the processor to implement the above-mentioned high-speed interior permanent magnet rotor design method based on the stress analysis model.

[0134] A fourth embodiment of the present invention provides a computer-readable storage medium storing computer instructions, wherein the computer instructions are used to be executed by the computer to implement the above-mentioned high-speed interior permanent magnet rotor design method based on the stress analysis model.

[0135] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes and related instructions of the storage device and processing device described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0136] Those skilled in the art should be able to appreciate that, in conjunction with the modules and method steps of each example described in the embodiments disclosed herein, it is possible to implement them with electronic hardware, computer software, or a combination of the two, and the programs corresponding to the software modules and method steps can be placed in random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium known in the art. In order to clearly illustrate the interchangeability of electronic hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in electronic hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0137] The terms "first", "second", etc. are used to distinguish similar objects, rather than to describe or indicate a particular order or sequence.

[0138] The term "comprise" or any other similar term is intended to cover non-exclusive inclusion such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0139] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A high-speed interior permanent magnet rotor design method based on a stress analysis model, characterized in that: The method includes: Based on the torque requirements and assembly space constraints of the high-speed permanent magnet synchronous motor, the rotor axial length and outer diameter are calculated, and the rotor dynamic characteristics are verified until the critical speed is higher than the target limit speed; The rotor is divided into pole shoes, permanent magnets and slotted areas, the centrifugal force of each area is calculated separately, and the total centrifugal force of the rotor is obtained by adding them together; Establishing a corresponding set of stress boundary condition equations according to the rotor structure type and the total centrifugal force of the rotor, wherein the rotor structure includes any one of a structure without a magnetic bridge, a structure with only an annular magnetic bridge, a structure with only a normal magnetic bridge, a structure with a combination of a sheath and an annular magnetic bridge, and a structure with a combination of a sheath and a normal magnetic bridge; According to the target limiting speed, the stress boundary condition equations are solved, and the optimized values ​​of the sheath thickness, magnetic bridge width and interference are determined through the intersection of the constant speed line and the relationship curve to complete the rotor parameter design.

2. The method for designing a high-speed interior permanent magnet rotor based on a stress analysis model according to claim 1, characterized in that: The centrifugal force of each region is calculated as follows: The pole shoe is decomposed into an annular region, an arcuate region and a trapezoidal sub-region. The pole shoe infinitesimal element is selected and the centrifugal forces of the annular region, the arcuate region and the trapezoidal sub-region are calculated based on the core material density and the rotational angular velocity. The centrifugal forces are then added together as the centrifugal forces of the pole shoe region. The mass of the permanent magnet is equivalent to the center of mass position, and the equivalent centrifugal force component is calculated based on the material density and cross-sectional area of ​​the permanent magnet as the permanent magnet centrifugal force; The slotted area is equivalent to negative mass, and the centrifugal force in the slotted area is calculated based on the hollowed area and the rotation radius.

3. The method for designing a high-speed interior permanent magnet rotor based on a stress analysis model according to claim 1, wherein: The corresponding stress boundary condition equations are established based on the non-magnetic bridge structure as follows: Where F is the total centrifugal force of the rotor, R ou is the outer radius of the sheath, R o is the outer radius of the core, R sle is the sheath thickness, R is the radius, σ rs is the sheath radial stress, σ θs is the sheath tangential stress, σ smax is the maximum allowable stress of carbon fiber material, L e is the axial length of the rotor, and α is the angle between the vertices of the permanent magnets on both sides and the center of the circle.

4. The method for designing a high-speed interior permanent magnet rotor based on a stress analysis model according to claim 1, wherein: The corresponding stress boundary condition equations are established based on the annular magnetic bridge structure only. The method is as follows: Among them, R i is the inner radius of the annular magnetic bridge, d ou is the thickness of the annular magnetic bridge, R o is the outer radius of the core, σ rg is the radial stress of the magnetic bridge, R is the radius, σ rθ is the tangential stress of the magnetic bridge, σ gmax is the maximum allowable stress of silicon steel sheet material, and F is the total centrifugal force of the rotor.

5. The method for designing a high-speed interior permanent magnet rotor based on a stress analysis model according to claim 1, wherein: The corresponding stress boundary condition equations are established based on the normal magnetic bridge structure as follows: L e d in s r =F; Among them, d in Normal magnetic bridge width, σ r Normal magnetic bridge stress, L e is the axial length of the rotor, and F is the total centrifugal force of the rotor.

6. The method for designing a high-speed interior permanent magnet rotor based on a stress analysis model according to claim 1, characterized in that: Based on the combined structure of the sheath and the annular magnetic bridge, the corresponding stress boundary condition equations are established as follows: Among them, R ou is the outer radius of the sheath, R o is the outer radius of the core, R sle is the sheath thickness, R is the radius, R i is the inner radius of the annular magnetic bridge, d ou is the thickness of the annular magnetic bridge, R o is the outer radius of the core, σ rs is the sheath radial stress, σ θs is the sheath tangential stress, σ θg is the tangential stress of silicon steel sheet material, σ gmax is the maximum allowable stress of silicon steel sheet material, σ smax is the maximum allowable stress of carbon fiber material, F is the total centrifugal force of the rotor, L e is the axial length of the rotor, α is the angle between the vertices of the permanent magnets on both sides and the center of the circle, σ rg is the radial stress of the magnetic bridge.

7. The method for designing a high-speed interior permanent magnet rotor based on a stress analysis model according to claim 1, characterized in that: Based on the combined structure of the sheath and the normal magnetic bridge, the corresponding stress boundary condition equations are established as follows: Among them, R ou is the outer radius of the sheath, R o is the outer radius of the core, R sle is the sheath thickness, R is the radius, σ θs is the sheath tangential stress, σ rs is the sheath radial stress, L e is the axial length of the rotor, σ gmax is the maximum allowable stress of silicon steel sheet material, F is the total centrifugal force of the rotor, d in Normal magnetic bridge width.

8. A high-speed interior permanent magnet rotor design system based on a stress analysis model, based on the high-speed interior permanent magnet rotor design method based on a stress analysis model according to any one of claims 1 to 7, characterized in that: The system includes: a rotor axial length and outer diameter calculation and verification module configured to calculate the rotor axial length and outer diameter based on the torque requirement and assembly space constraints of the high-speed permanent magnet synchronous motor, and to verify the rotor dynamic characteristics until the critical speed is higher than the target limit speed; A total centrifugal force calculation module is configured to divide the rotor into pole shoes, permanent magnets, and slotted areas, calculate the centrifugal force of each area separately, and add them together to obtain the total centrifugal force of the rotor; a stress boundary condition equation group construction module configured to establish a corresponding stress boundary condition equation group according to a rotor structure type in combination with a total centrifugal force of the rotor, wherein the rotor structure includes any one of a structure without a magnetic bridge, a structure with only an annular magnetic bridge, a structure with only a normal magnetic bridge, a structure with a combination of a sheath and an annular magnetic bridge, and a structure with a combination of a sheath and a normal magnetic bridge; The rotor parameter design module is configured to solve the stress boundary condition equations according to the target limit speed, determine the optimized values ​​of the sheath thickness, magnetic bridge width and interference through the intersection of the constant speed line and the relationship curve, and complete the rotor parameter design.

9. An electronic device, characterized in that: include: at least one processor; as well as a memory communicatively connected to at least one of the processors; wherein, The memory stores instructions that can be executed by the processor, and the instructions are used to be executed by the processor to implement the high-speed interior permanent magnet rotor design method based on a stress analysis model as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, and the computer instructions are used to be executed by the computer to implement the high-speed interior permanent magnet rotor design method based on a stress analysis model according to any one of claims 1 to 7.

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