A method for designing a motor rotor lamination and a motor rotor lamination

Abstract

The application relates to the technical field of motors, in particular to a motor rotor punching sheet design method and a motor rotor punching sheet. The motor rotor punching sheet design method comprises the following steps: S1, setting the number m of modulation hollow structures on the motor rotor punching sheet; S2, setting a first slope value k and a second slope value -k; S3, determining the expression of a plurality of first inclined lines and the expression of a plurality of second inclined lines; S4, solving the numerical value; S5, converting the numerical value from the electrical period radian to the mechanical radian according to the motor pole number; S6, judging whether the width of the modulation hollow structure under the corresponding mechanical radian satisfies the punching requirement; if yes, the next step is performed; S7, judging whether the magnetic field harmonic of the motor rotor composed of the motor rotor punching sheet satisfies the requirement; if yes, the design is completed. The motor rotor punching sheet design method can improve the air gap magnetic flux density sinusoidal degree of the motor rotor punching sheet, thereby facilitating the motor to realize high efficiency, low fluctuation and low electromagnetic noise.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric machines, in particular to a design method of an electric machine rotor punching sheet and an electric machine rotor punching sheet. BACKGROUND

[0002] With the development of new energy technology, electric machines are more and more widely used in vehicles. Electric machines are the core of new energy vehicles, and the performance of electric machines determines the performance of vehicles.

[0003] In order to further improve the efficiency level of the electric machine and reduce the electromagnetic noise level of the electric machine, the air gap magnetic density of the electric machine needs to be improved to be more sinusoidal, thereby reducing the iron loss and electromagnetic excitation force and improving the competitiveness of the electric machine. However, in the prior art, the sinusoidal degree of the air gap magnetic density of the electric machine rotor punching sheet is poor, the air gap harmonic content is high, the no-load back EMF harmonic content is high, and the electric machine has problems such as large core loss, large fluctuation, large electromagnetic noise, and poor control stability.

[0004] Therefore, a design method of an electric machine rotor punching sheet and an electric machine rotor punching sheet are needed to solve the above technical problems. SUMMARY

[0005] The purpose of the present application is to provide a design method of an electric machine rotor punching sheet and an electric machine rotor punching sheet, which can improve the sinusoidal degree of the air gap magnetic density of the electric machine rotor punching sheet, realize low air gap magnetic density harmonic content, i.e. low no-load back EMF harmonic content, thereby facilitating the electric machine to realize high efficiency, low fluctuation, and low electromagnetic noise.

[0006] To achieve this purpose, the present application adopts the following technical solutions:

[0007] A design method of an electric machine rotor punching sheet, comprising the following steps:

[0008] S1, setting the number m of modulation hollow structures opened on the electric machine rotor punching sheet;

[0009] S2, setting the first slope value k of the first inclined line and the second slope value -k of the second inclined line in the triangular carrier curve;

[0010] S3, determining the expression of a plurality of first inclined lines with the first slope value k, and determining the expression of a plurality of second inclined lines with the second slope value -k;

[0011] S4, solving the numerical solution by combining the unit sinusoidal curve with the expression of the first inclined line and the expression of the second inclined line;

[0012] S5, converting the numerical solution from electric period radian to mechanical radian according to the number of poles of the electric machine;

[0013] S6. Determine whether the width of the modulated hollow structure under the corresponding mechanical curvature meets the stamping requirements. If yes, proceed to the next step.

[0014] S7. Determine whether the magnetic field harmonics of the motor rotor composed of the motor rotor laminations meet the requirements; if they do, the design is complete.

[0015] As an optional design method for motor rotor laminations, in step S7, if the magnetic field harmonics do not meet the requirements, the process returns to step S1.

[0016] As an optional design method for motor rotor laminations, the amplitude of the triangular carrier curve is greater than the amplitude of the unit sine curve.

[0017] As an optional design method for motor rotor laminations, if the stamping requirements are not met in step S6, the process returns to step S2.

[0018] As an optional design method for motor rotor laminations, in step S1, the modulation hollow structure includes an odd number of modulation hollow holes, which are spaced apart on the motor rotor laminations along the circumferential direction.

[0019] As an optional design method for motor rotor laminations, the distance from the modulation hollow hole to the inner annular surface of the motor rotor lamination is greater than the distance from the modulation hollow hole to the outer annular surface of the motor rotor lamination.

[0020] As an optional design method for motor rotor laminations, in step S1, the modulation hollow structure includes an odd number of modulation hollow slots, which are spaced apart along the circumference of the motor rotor laminations at the edges of the motor rotor laminations.

[0021] An electric motor rotor lamination is designed and manufactured using the electric motor rotor lamination design method described above.

[0022] As an optional solution for motor rotor laminations, the motor rotor laminations include: a motor rotor core, multiple permanent magnets and a modulated hollow structure. Multiple mounting slots are spaced apart on the motor rotor core, and the multiple mounting slots are arranged in a one-to-one correspondence with the multiple permanent magnets. The modulated hollow structure is formed on the motor rotor core.

[0023] As an optional solution for motor rotor laminations, the mounting slot is in the shape of an "I", a "V" or a double "I".

[0024] The beneficial effects of this invention are:

[0025] The present invention provides a design method for motor rotor laminations. First, the number *m* of modulation hollow structures to be formed on the motor rotor laminations is set. Then, the slope value of the triangular carrier curve is set, and expressions for the first and second slopes are constructed. These expressions are then combined with a unit sine curve to obtain a numerical solution. The numerical solution is converted into mechanical radians corresponding to the number of motor poles. The width of the modulation hollow structures is designed based on the mechanical radians. If the modulation hollow structures meet the stamping requirements, and the magnetic field harmonics of the motor rotor composed of the motor rotor laminations meet the requirements, the design is complete. The motor rotor laminations designed in this way satisfy the requirements for forming modulation hollow structures. Furthermore, by utilizing the modulation hollow structures, the air gap magnetic flux density shape of the motor rotor is improved, making the air gap harmonics sinusoidal and exhibiting low harmonic content. This facilitates the motor to achieve high efficiency, low fluctuation, and low electromagnetic noise.

[0026] The present invention provides a motor rotor lamination with multiple mounting slots spaced apart on the motor rotor core. Each mounting slot corresponds to a permanent magnet, and a modulated hollow structure is formed on the motor rotor core. By forming the modulated hollow structure, the air gap magnetic flux density shape of the motor rotor is improved, making the air gap harmonics sinusoidal and exhibiting low harmonic content. This facilitates the motor to achieve high efficiency, low fluctuation, and low electromagnetic noise. (See attached figures.)

[0027] Figure 1 This is a flowchart of a design method for a motor rotor lamination according to the present invention;

[0028] Figure 2 This is a schematic diagram of a motor rotor lamination according to the present invention;

[0029] Figure 3 This is a schematic diagram of another type of motor rotor lamination according to the present invention;

[0030] Figure 4 This is a diagram illustrating the design principle of a modulation hollow structure for a motor rotor lamination according to the present invention.

[0031] In the picture:

[0032] 1. Motor rotor core; 2. Permanent magnet; 3. Modulation hollow hole; 4. Modulation hollow slot; 5. Sine curve; 6. Triangular carrier curve; 7. Duty cycle curve. Detailed Implementation

[0033] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings, not all of them.

[0034] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0035] In the present application, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "upper", "above" and "on" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "lower", "below" and "under" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0036] With the development of new energy technology, the application of electric machines in vehicles is becoming more and more extensive. The electric machine is the core of the energy vehicle, and the performance of the electric machine determines the performance of the vehicle.

[0037] In order to further improve the efficiency level of the electric machine and reduce the electromagnetic noise level of the electric machine, the air gap magnetic density of the electric machine needs to be improved to be more sinusoidal, thereby reducing the iron loss and electromagnetic excitation force and improving the competitiveness of the electric machine. However, in the prior art, the sinusoidal degree of the air gap magnetic density of the rotor lamination of the electric machine is poor, the air gap harmonic content is high, and the no-load back electromotive force harmonic content is high, which leads to problems such as large electric machine core loss, large fluctuation, large electromagnetic noise, and poor control stability.

[0038] In order to solve the above problems, the sinusoidal degree of the air gap magnetic density of the rotor lamination of the electric machine can be improved, and the air gap magnetic density harmonic content, i.e. the no-load back electromotive force harmonic content, is low, thereby facilitating the electric machine to realize high efficiency, low fluctuation and low electromagnetic noise. As shown in Figures 1-4 The present application provides a design method of an electric machine rotor lamination. The design method of the electric machine rotor lamination comprises the following steps:

[0039] S1, setting the number m of the modulation hollow structure opened on the electric machine rotor lamination;

[0040] S2, setting the first slope value k of the first inclined line and the second slope value -k of the second inclined line in the triangular carrier curve 6;

[0041] S3, determining the expression of the plurality of first inclined lines with the first slope value k, and determining the expression of the plurality of second inclined lines with the second slope value -k;

[0042] S4, solving the numerical solution by taking the expression of the unit sinusoidal curve 5 and the expression of the first inclined line and the expression of the second inclined line together;

[0043] S5, converting the numerical solution from the electrical cycle radian to the mechanical radian according to the number of motor poles;

[0044] S6, judging whether the width of the modulation hollow structure corresponding to the mechanical radian meets the stamping requirement, and if so, proceeding to the next step;

[0045] S7, judging whether the magnetic field harmonic of the motor rotor composed of the motor rotor punching sheet meets the requirement; if so, the design is completed.

[0046] The motor rotor punching sheet designed in the above manner meets the requirement of opening the modulation hollow structure on one hand, and improves the air gap magnetic flux density shape of the motor rotor by using the modulation hollow structure, makes the air gap harmonic sinusoidal, has the characteristics of low harmonic content, thereby facilitating the motor to realize high efficiency, low fluctuation and low electromagnetic noise.

[0047] As an optional scheme of the design method of the motor rotor punching sheet, in step S7, if the magnetic field harmonic does not meet the requirement, return to step S1. Specifically, after the design is completed, the simulation software is used to simulate the design result, the motor rotor is assembled in the simulation software, and then the magnetic field harmonic of the motor rotor composed of the motor rotor punching sheet is judged, so that the design result can be known before manufacturing, the result can be verified in advance, and the processing failure leading to non-use is avoided. If the magnetic field harmonic of the motor rotor meets the requirement, actual processing is performed for verification, and if it does not meet the requirement, it is proved that the number m of the modulation hollow structure opened on the motor rotor punching sheet is problematic, and the design is re-designed.

[0048] As an optional scheme of the design method of the motor rotor punching sheet, the amplitude of the triangular carrier curve 6 is greater than the amplitude of the unit sinusoidal curve 5. Specifically, in the embodiment, the amplitude of the sinusoidal curve 5 is 1, by making the amplitude of the triangular carrier curve 6 greater than the amplitude of the unit sinusoidal curve 5, it can be ensured that the numerical solution of the triangular carrier curve 6 and the sinusoidal curve 5 at the amplitude of the sinusoidal curve 5 can be solved, thereby improving the sinusoidal degree of the air gap magnetic flux density of the motor rotor punching sheet.

[0049] As an optional scheme of the design method of the motor rotor punching sheet, in step S6, if the stamping requirement is not met, return to step S2. In the above manner, it can be avoided that the design is problematic so as to be unable to be processed, by adjusting the first slope value k of the first inclined line and the second slope value -k of the second inclined line, the width of the modulation hollow structure can be changed, thereby making the designed motor rotor punching sheet processable.

[0050] As an alternative to the design method of the motor rotor lamination, in step S1, the modulated hollow structure includes an odd number of modulated hollow holes 3, which are arranged on the motor rotor lamination at intervals along the circumference of the motor rotor lamination. Specifically, in this embodiment, the distance from the modulated hollow hole 3 to the inner ring surface of the motor rotor lamination is greater than the distance from the modulated hollow hole 3 to the outer ring surface of the motor rotor lamination. By improving the air gap flux density shape of the motor rotor with the modulated hollow hole 3, the air gap harmonics are sinusoidal, with the characteristic of low harmonic content, thereby facilitating the motor to achieve high efficiency, low fluctuation, and low electromagnetic noise. Moreover, the modulated hollow hole 3 is easy to process on the motor rotor lamination. However, this processing method may affect the strength of the motor rotor lamination. In order to ensure the strength of the motor rotor lamination, epoxy resin or other non-magnetic materials such as plastic can be filled in the modulated hollow hole 3.

[0051] As an alternative to the design method of the motor rotor lamination, in step S1, the modulated hollow structure includes an odd number of modulated hollow slots 4, which are arranged at the edge of the motor rotor lamination at intervals along the circumference of the motor rotor lamination. By improving the air gap flux density shape of the motor rotor with the modulated hollow slot 4, the air gap harmonics are sinusoidal, with the characteristic of low harmonic content, thereby facilitating the motor to achieve high efficiency, low fluctuation, and low electromagnetic noise. Moreover, the modulated hollow slot 4 is easy to process on the motor rotor lamination, and will not excessively affect the strength of the motor rotor lamination.

[0052] Specifically, as shown in FIG. 6, Figure 4 wherein 5 is a unit sinusoidal curve with an amplitude of 1, 6 is a triangular carrier curve, and 7 is a duty cycle curve after modulation. Assuming that the motor pole number is 2p, and the number of modulated hollow structures corresponding to each pole is m. A Cartesian coordinate system is established with the starting point of the sinusoidal curve 5 as the origin, and the function of the sinusoidal curve 5 is y=sinx. It is easy to know that the intersection of the triangular carrier curve 6 and the x-axis is π / 2m, 3π / 2m, 5π / 2m, 7π / 2m…61, 63, 65, 67…are a family of straight lines that are constantly translated to the right by π / m and have a slope of -k (assuming k>0), and 62, 64, 66…are a family of straight lines that are constantly translated to the right by π / m and have a slope of k.

[0053] It is easy to know that the equation of the 61, 63, 65, 67…straight line family is:

[0054]

[0055] It is easy to know that the equation of the 62, 64, 66…straight line family is:

[0056]

[0057] It is necessary to ensure that the amplitude of the triangular carrier curve 6 is greater than the unit sinusoidal curve 5, so it is necessary to ensure that k>2m / π.

[0058] The respective transcendental equations are composed of the above straight lines and the sinusoidal curves 5, and the numerical solutions of the respective transcendental equations are obtained by numerical solving software, i.e., x1, x2, x3…

[0059] Since the number of poles of the motor is 2p, the mechanical radian under each pole corresponding to x1, x2, x3… is x1 / p, x2 / p, x3 / p…

[0060] Further, for the first type of rotor topology, the modulation hollow hole 3 corresponds to the width of R3x1 / p, R3(x3 / p-x2 / p), R3(x5 / p-x4 / p), R3(x7 / p-x6 / p)… The gap of the motor rotor core 1 corresponds to the width of R3(x2 / p-x1 / p), R3(x4 / p-x3 / p), R3(x6 / p-x5 / p)…, wherein R3 is the radius corresponding to the side of the edge of the modulation hollow hole 3 away from the motor rotor lamination.

[0061] Further, for the second type of rotor topology, the modulation hollow slot 4 corresponds to the width of R4x1 / p, R4(x3 / p-x2 / p), R4(x5 / p-x4 / p), R4(x7 / p-x6 / p)… The gap of the motor rotor core 1 corresponds to the width of R4(x2 / p-x1 / p), R4(x4 / p-x3 / p), R4(x6 / p-x5 / p)…, wherein R4 is the radius corresponding to the bottom of the modulation hollow slot 4.

[0062] In order to ensure the stampability of the rotor lamination, the value of k needs to be adjusted continuously to ensure that the above gaps are greater than the minimum stampable gap.

[0063] The embodiment also provides a motor rotor lamination designed and manufactured by the design method of the motor rotor lamination as described above. The motor rotor lamination includes a motor rotor core 1, a plurality of permanent magnets 2, and a modulation hollow structure. A plurality of installation slots are arranged on the motor rotor core 1 in a spaced manner, and the plurality of installation slots are arranged in one-to-one correspondence with the plurality of permanent magnets 2. The modulation hollow structure is arranged on the motor rotor core 1. The installation slots are arranged to facilitate the installation of the motor rotor core 1. The modulation hollow structure can be a modulation hollow hole 3 or a modulation hollow slot 4. It is worth noting that the modulation hollow hole 3 or the modulation hollow slot 4 is odd. The modulation hollow structure is arranged to improve the air gap flux density shape of the motor rotor, make the air gap harmonic sinusoidal, and have the characteristics of low harmonic content, thereby facilitating the motor to achieve high efficiency, low fluctuation, and low electromagnetic noise.

[0064] As an alternative to the motor rotor lamination, the mounting slot is in the shape of a "I", a "V" or a double "I". In other embodiments, the structure of the mounting slot can also be a "V" plus a "I", a double "V", without being limited too much here. By providing the mounting slot, the installation of the motor rotor core 1 is facilitated.

[0065] Obviously, the above-mentioned embodiments of the present application are merely examples for clearly explaining the present application, and are not intended to limit the embodiments of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, it is not necessary and impossible to exhaust all the embodiments. Any modification, equivalent replacement and improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A method of designing an electrical machine rotor lamination, characterized by, The method comprises the following steps: S1, setting the number m of modulation hollow structures on the motor rotor lamination; S2, setting the first slope value k of the first slope line and the second slope value -k of the second slope line in the triangular carrier curve (6); S3, determining the expression of the first slope line with the first slope value k and the expression of the second slope line with the second slope value -k; S4, solving the numerical value with the unit sinusoidal curve (5) and the expressions of the first slope line and the second slope line; S5, converting the numerical value from electrical cycle radian to mechanical radian according to the number of motor poles; S6, judging whether the width of the modulation hollow structure corresponding to the mechanical radian meets the stamping requirement, and if yes, proceeding to the next step; S7, judging whether the magnetic field harmonic of the motor rotor composed of the motor rotor lamination meets the requirement, and if yes, the design is completed; In the step S1, the modulation hollow structure comprises an odd number of modulation hollow holes (3) which are arranged on the motor rotor lamination at intervals along the circumference of the motor rotor lamination; or the modulation hollow structure comprises an odd number of modulation hollow grooves (4) which are arranged at the edge of the motor rotor lamination at intervals along the circumference of the motor rotor lamination. The unit sinusoidal curve (5) is taken as the origin to establish a Cartesian coordinate system, the first slope line is a family of straight lines which are translated to the right by π / m and have a slope k, and the second slope line is a family of straight lines which are translated to the right by π / m and have a slope -k, wherein k>0.

2. A method of designing a motor rotor lamination according to claim 1, wherein, In the step S7, if the magnetic field harmonic does not meet the requirement, the step S1 is returned to.

3. The method of designing a motor rotor lamination as recited in claim 1 wherein, The amplitude of the triangular carrier curve (6) is greater than that of the unit sinusoidal curve (5).

4. The method of designing an electrical machine rotor lamination according to claim 1, characterized in that, In the step S6, if the stamping requirement is not met, the step S2 is returned to.

5. The method of designing an electrical machine rotor lamination as claimed in claim 1, wherein, The distance from the modulation hollow hole (3) to the inner ring surface of the motor rotor lamination is greater than the distance from the modulation hollow hole (3) to the outer ring surface of the motor rotor lamination.

6. An electrical machine rotor lamination, characterized by The motor rotor lamination is manufactured by using the design method of any one of claims 1-5.

7. An electrical machine rotor lamination according to claim 6, characterized in that The motor rotor lamination comprises a motor rotor core (1), a plurality of permanent magnets (2) and a modulation hollow structure, the motor rotor core (1) is provided with a plurality of installation grooves at intervals, the plurality of installation grooves are arranged in one-to-one correspondence with the plurality of permanent magnets (2), and the modulation hollow structure is arranged on the motor rotor core (1).

8. An electrical machine rotor lamination according to claim 7, characterized in that The installation groove is in the shape of "I", "V" or double "I".

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