Permanent magnet synchronous motor and its design method, gyro north finder

Abstract

The present invention relates to a permanent magnet synchronous motor, a design method thereof, and a gyro north finder. The permanent magnet synchronous motor includes a stator, which includes a stator core, an N-pole magnet, and an S-pole magnet. The N-pole magnet and the S-pole magnet are alternately arranged on the inner side of the stator core along the circumference of the stator core. The rotor includes a rotor core and a flexible circuit board winding. The rotor core and the stator core are concentrically arranged, with the rotor core located on the inner side of the stator core, and the flexible circuit board winding is arranged around the outer side of the rotor core. The flexible circuit board winding includes wiring layers stacked along the thickness direction of the flexible circuit board winding when it is unfolded. Each wiring layer includes a conductive block having a parallelogram-shaped planar shape. The short side of the conductive block is arranged along the length direction of the flexible circuit board winding when it is unfolded. The multiple conductive blocks are spaced and insulated along the length direction of the flexible circuit board winding when it is unfolded.

Description

Technical Field

[0001] The present disclosure relates to the field of electromechanical technology, and in particular to a permanent magnet synchronous motor and a design method thereof, and a gyro north finder. Background Art

[0002] As the driving component of a north-finder based on rotary modulation technology, the motor is a key component. Currently available commercial micromotors on the market are not large enough to meet the needs of miniaturized north-finders, so motor miniaturization has become a key design direction. Summary of the Invention

[0003] The present disclosure provides a permanent magnet synchronous motor and a design method thereof, and a gyro north finder to address deficiencies in related technologies.

[0004] According to a first aspect of an embodiment of the present disclosure, a permanent magnet synchronous motor is provided, comprising:

[0005] A stator, the stator comprising a stator core, an N-pole magnet and an S-pole magnet, wherein the N-pole magnet and the S-pole magnet are alternately arranged on an inner side of the stator core along a circumferential direction of the stator core;

[0006] A rotor, the rotor comprising a rotor core and a flexible circuit board winding, the rotor core and the stator core being concentrically arranged, the rotor core being located inside the stator core, and the flexible circuit board winding being arranged around the outside of the rotor core;

[0007] The flexible circuit board winding includes routing layers stacked along the thickness direction of the flexible circuit board winding when it is unfolded, each routing layer includes a conductive block with a parallelogram planar shape, the short side of the conductive block is arranged along the length direction of the flexible circuit board winding when it is unfolded, and multiple conductive blocks are spaced and insulated along the length direction of the flexible circuit board winding when it is unfolded.

[0008] Optionally, the long sides of the parallelogram are all inclined relative to the width direction of the flexible circuit board winding when it is unfolded;

[0009] The number of layers of the routing layers is even, and in the stacking direction of the routing layers, the long sides of the conductive blocks of the routing layers with odd numbers have the same inclination direction and equal inclination angles, and the long sides of the conductive blocks of the routing layers with even numbers have the same inclination direction and equal inclination angles;

[0010] The inclination direction of the long sides of the conductive blocks of the routing layers with even numbers is opposite to the inclination direction of the long sides of the conductive blocks of the routing layers with odd numbers.

[0011] Optionally, the flexible circuit board winding includes an nth routing layer and an n+1th routing layer, where n is an odd number; the nth routing layer includes a plurality of first conductive blocks, and the n+1th routing layer includes a plurality of second conductive blocks;

[0012] The plurality of second conductive blocks are divided into an overlapping area and a first protruding area, wherein the overlapping area is located below the nth wiring layer, and the protruding area is partially protruded relative to the nth wiring layer;

[0013] In the overlapped area and the nth wiring layer, the same phase current flows alternately through the first conductive block and the second conductive block;

[0014] The nth routing layer is provided with a second protruding area protruding relative to the n+1th routing layer, and the second protruding area is provided with 2m first conductive blocks, wherein the first m first conductive blocks correspond one-to-one to the m different-phase input currents, and the last m first conductive blocks correspond one-to-one to the m different-phase output currents, where m is the number of winding phases and is greater than 1;

[0015] Among the 2m second conductive blocks in the first protruding area, the wth second conductive block and the w+mth second conductive block are electrically connected, so that the same-phase currents are reversed in the length direction of the flexible circuit board winding when it is unfolded.

[0016] Optionally, the flexible circuit board winding further includes metallized vias, each of the metallized vias connecting a single first conductive block and a single second conductive block.

[0017] Optionally, the flexible circuit board winding is wound around the rotor core K times, where K is greater than or equal to 1;

[0018] The number of conductive blocks in the multiple routing layers of all flexible circuit board windings is equal.

[0019] Optionally, the rotor core comprises multiple layers of concentrically arranged annular silicon steel sheets; and / or,

[0020] The S-pole magnet and the N-pole magnet have the same planar shape and the same corresponding size parameters; the planar shape of the S-pole magnet includes a rectangle and an isosceles trapezoid, and the lower base of the isosceles trapezoid is connected to the long side of the rectangle.

[0021] Optionally, the corners of the S-pole magnet and the N-pole magnet are both provided with arc chamfers; and / or

[0022] The flexible circuit board winding is a two-phase winding.

[0023] According to a second aspect of an embodiment of the present disclosure, a gyro north finder is provided, comprising a permanent magnet synchronous motor as described in any one of the above embodiments.

[0024] According to a third aspect of an embodiment of the present disclosure, a design method for a permanent magnet synchronous motor is provided, which is applied to the permanent magnet synchronous motor according to any one of the above embodiments. The design method includes:

[0025] Determine the stator core outer diameter, rotor core inner diameter, and motor torque based on the size of components required to be assembled on the rotor core inner ring, the size of components assembled on the stator core outer ring, and the load capacity requirements of the permanent magnet synchronous motor;

[0026] Based on the motor size and performance requirements of the permanent magnet synchronous motor, determine whether it has brushes, the motor power supply waveform, the number of motor phases and the drive mode;

[0027] The magnetic flux density waveform distortion of the permanent magnet synchronous motor is used as the optimization objective function, and the outer diameter size of the stator core, the inner diameter size of the rotor core and the actual processing and manufacturing requirements are used as the constraints of the optimization parameters. Within the value range of the stator core thickness, the value range of the rotor core thickness, the value range of the air gap thickness, the value range of the winding thickness, the value range of the magnet shape and the value range of each magnet size parameter, the static magnetic field simulation is performed on the three-dimensional model of the permanent magnet synchronous motor, and the traversal optimization is performed to obtain the optimal solution of the stator core thickness, the optimal solution of the rotor core thickness, the optimal solution of the air gap thickness value, the optimal solution of the winding thickness, the optimal solution of the magnet shape and the optimal solution of each magnet size.

[0028] Optionally, also include:

[0029] Generate a flexible circuit board graphic with positioning lines based on the optimal solution for the winding thickness, the optimal solution for the rotor core thickness, and the winding parameters. The positioning lines are used to locate the position of the conductive blocks after the flexible circuit board winding is wound around the rotor core. The winding parameters include the number of conductive blocks per pole and per phase, the number of winding turns, the insulating gap between the conductive blocks, the axial margin of the conductive blocks, the circumferential margin of the conductive blocks, the inner diameter of the metallized vias, the outer diameter of the metallized vias, the center-to-center spacing of the metallized vias, the circumferential margin of the metallized vias, the axial margin of the inner diameter of the metallized vias, and the spacing angle of the positioning lines.

[0030] The flexible circuit board pattern is post-processed to obtain a flexible circuit board winding for processing, wherein the post-processing includes setting design rules, batch copper plating of conductive block patterns, adding mechanical layer outlines and design rule checking.

[0031] The technical solutions provided by the embodiments of the present disclosure may have the following beneficial effects:

[0032] It can be seen from the above embodiments that the design of the flexible circuit board winding in the present disclosure can be wound around the outside of the rotor core, with light weight, small volume, and is conducive to programmed design and mass production; based on the fact that the inner diameter of the stator core is larger than the outer diameter of the rotor core, more N-pole magnets and S-pole magnets can be embedded, thereby improving the magnetic flux density of the permanent magnet synchronous motor; the flexible circuit board winding can increase the conductive area by setting the conductive block with a parallelogram plane shape, thereby increasing the force area of ​​the flexible circuit board winding in the magnetic field, improving space utilization, and based on a permanent magnet synchronous motor of equal volume, it is beneficial to improve the motor torque of the permanent magnet synchronous motor, and under the condition of the same motor torque requirements, it is beneficial to achieve the miniaturization of the permanent magnet synchronous motor.

[0033] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0035] Figure 1 is a partial schematic diagram of a permanent magnet synchronous motor according to an exemplary embodiment.

[0036] Figure 2 It is a partial cross-sectional schematic diagram of a permanent magnet synchronous motor according to an exemplary embodiment.

[0037] Figure 3 The figure is a front view schematic diagram showing a flexible circuit board winding in an unfolded state according to an exemplary embodiment.

[0038] Figure 4 The figure is a schematic back view of a flexible circuit board winding in an unfolded state according to an exemplary embodiment.

[0039] Figure 5 The figure is a schematic diagram showing the current flow direction when a flexible circuit board winding is in an unfolded state according to an exemplary embodiment.

[0040] Figure 6 It is a schematic diagram showing the cooperation between an N-pole magnet and a stator core according to an exemplary embodiment.

[0041] Figure 7 The figure is a flow chart of a design method of a permanent magnet synchronous motor according to an exemplary embodiment.

[0042] Figure 8 The figure is a curve showing the relationship between the circumferential width of a magnet and the average magnetic flux density distortion of a flexible circuit board winding according to an exemplary embodiment.

[0043] Figure 9 The figure is a flow chart of another design method of a permanent magnet synchronous motor according to an exemplary embodiment. DETAILED DESCRIPTION

[0044] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

[0045] The terms used in this disclosure are for the purpose of describing specific embodiments only and are not intended to limit the disclosure. As used in this disclosure and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0046] It should be understood that although the terms first, second, third, etc. may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining."

[0047] Figure 1 is a partial schematic diagram of a permanent magnet synchronous motor according to an exemplary embodiment. Figure 2 FIG is a partial cross-sectional schematic diagram of a permanent magnet synchronous motor according to an exemplary embodiment. Figure 1 and Figure 2 As shown, the permanent magnet synchronous motor includes a stator and a rotor, wherein the stator includes a stator core 1, an N-pole magnet 3 and an S-pole magnet 4, and the rotor includes a rotor core 2 and a flexible circuit board winding 5. The rotor core 2 is concentrically arranged with the stator core 1, and the rotor core 2 is located on the inner side of the stator core 1. The N-pole magnets 3 and the S-pole magnets 4 are alternately arranged on the inner side of the stator core 1 along the circumference of the stator core 1, and the number of the N-pole magnets 3 and the S-pole magnets 4 are equal. Compared with the solution in the related art in which the magnets are arranged on the rotor and the windings are arranged on the stator, the inner diameter of the stator core 1 in the present disclosure is larger than the outer diameter of the rotor core 2, and more N-pole magnets 3 and S-pole magnets 4 can be embedded to improve the magnetic flux density. For example, if Figure 1 and Figure 2As shown, the stator core 1 is provided with multiple protrusions 11 on its inner side, with grooves formed between adjacent protrusions 11. Each groove accommodates a single north-pole magnet 3 or a single south-pole magnet 4. A flexible circuit board winding 5 is arranged around the outside of the rotor core 2. The design of the flexible circuit board winding 5 allows it to be wound around the outside of the rotor core, resulting in a lightweight and compact design, and facilitating programmable design and mass production.

[0048] The flexible circuit board winding 5 includes routing layers stacked along the thickness direction of the flexible circuit board winding 5 when unfolded. Each routing layer includes conductive blocks in a parallelogram-shaped planar shape, with the short sides of the conductive blocks arranged along the length direction of the flexible circuit board winding 5 when unfolded. The multiple conductive blocks are spaced and insulated along the length direction of the flexible circuit board winding 5 when unfolded. Based on this, the conductive blocks arranged in a parallelogram shape can increase the conductive area, thereby increasing the force-bearing area of ​​the flexible circuit board winding 5 in the magnetic field. Based on a permanent magnet synchronous motor of equal volume, this is beneficial for improving the motor torque of the permanent magnet synchronous motor and, under the condition of the same motor torque requirement, is beneficial for miniaturizing the permanent magnet synchronous motor. The number of conductive blocks in the multiple routing layers is equal.

[0049] The long sides of the parallelogram-shaped conductive blocks are tilted relative to the width of the flexible circuit board winding 5 when it is unfolded. The number of routing layers is even. In the stacking direction of the routing layers, the long sides of the conductive blocks of the odd-numbered routing layers have the same tilt direction and equal tilt angle, while the long sides of the conductive blocks of the even-numbered routing layers have the same tilt direction and equal tilt angle. The long sides of the conductive blocks of the even-numbered routing layers have the opposite tilt direction to the long sides of the conductive blocks of the odd-numbered routing layers. For example, if the flexible circuit board winding 5 includes four routing layers, the long sides of the first and third routing layers have the same tilt direction and equal tilt angle, the long sides of the second and fourth routing layers have the same tilt direction and equal tilt angle, and the long sides of the first and second routing layers have opposite tilt directions and equal tilt angle. This is conducive to achieving electrical connection between the first routing layer and the second routing layer, and electrical connection between the third routing layer and the fourth routing layer, thereby realizing oblique transmission of electrical signals.

[0050] For example, Figure 3 and Figure 4As shown, the flexible circuit board winding 5 includes an nth routing layer 51 and an n+1th routing layer 52, where n is an odd number. The nth routing layer 51 includes a plurality of first conductive blocks 511, and the n+1th routing layer 52 includes a plurality of second conductive blocks 521. The plurality of first conductive blocks 511 are arranged along the length direction of the flexible circuit board winding 5 when it is unfolded, and adjacent first conductive blocks 511 are spaced and insulated. The plurality of second conductive blocks 521 are arranged along the length direction of the flexible circuit board winding 5 when it is unfolded, and adjacent second conductive blocks 521 are spaced and insulated. Figure 3 and Figure 4 As shown, the plane shape of the first conductive block 511 is a parallelogram, the plane shape of the second conductive block 521 is also a parallelogram, and the short side of the parallelogram is arranged along the length direction of the flexible circuit board winding 5, that is, Figure 3 and Figure 4 Arranged in left and right directions.

[0051] In some embodiments, the long sides of the first conductive block 511 and the second conductive block 521 can be arranged parallel to the width direction of the flexible circuit board winding 5 when it is unfolded; in other embodiments, the long sides of the first conductive block 511 and the second conductive block 521 are arranged obliquely relative to the width direction of the flexible circuit board winding 5 when it is unfolded, and the oblique directions of the first conductive block 511 and the second conductive block 521 are opposite and the oblique angles are equal. Figure 5 As shown in FIG, the first conductive block 511 is tilted to the left relative to the width of the flexible circuit board winding 5 when it is unfolded, and the second conductive block 521 is tilted to the right relative to the width of the flexible circuit board winding 5 when it is unfolded. Based on this design, it is convenient to achieve electrical connection between the nth routing layer 51 and the (n+1)th routing layer 52, and it can transmit electrical signals at an angle.

[0052] For example, Figure 5 As shown, the plurality of second conductive blocks 521 can be divided into an overlapped area 522 and a first protruding area 523, wherein the overlapped area 522 is located below the nth wiring layer 51, and the first protruding area is partially protruded relative to the nth wiring layer; for example Figure 5In the figure, the first protruding area 523 is located in the lower right area. In the overlapping area 522 of the (n+1)th routing layer 52 and the nth routing layer 51, the same phase current alternately flows through the first conductive block 511 and the second conductive block 521. For example, the flexible circuit board winding 5 also includes metallized vias, each of which connects a single first conductive block 511 and a second conductive block 521, thereby enabling current transmission between the nth routing layer 51 and the n+1th routing layer 52. The nth routing layer 511 is provided with a second protruding area 512 that protrudes relative to the (n+1)th routing layer 521. The second protruding area 512 is provided with 2m first conductive blocks. The first m first conductive blocks 511 correspond one-to-one to the m different phases of the input current, where m is the number of winding phases and is greater than 1. The last m first conductive blocks 511 correspond one-to-one to the m different phases of the output current.

[0053] For example, Figure 5 As shown, assuming that the flexible circuit board winding 5 is a two-phase winding, for example, the flexible circuit board winding 5 carries a Sin-phase current and a Cos-phase current, with a phase difference of 90°. The current indicated by the red line is the Sin-phase current, and the current indicated by the green arrow is the Cos-phase current. From left to right, the Sin-phase current is input from the first first conductive block 511, then transmitted through the first second conductive block 521 to the fifth first conductive block 511, then through the fifth second conductive block 521 to the ninth first conductive block 511, and so on. Similarly, the Cos-phase current is output from the second first conductive block 511, then transmitted through the second second conductive block 521 to the sixth first conductive block 511, then through the sixth second conductive block 521 to the tenth first conductive block 511, and so on. This achieves the transmission of the first and second phase currents from left to right.

[0054] As can be seen from the above transmission method, some of the first conductive blocks 511 and the second conductive blocks 521 are not used to transmit current. Therefore, in order to improve the utilization rate, among the 2m second conductive blocks 521 in the first protruding area 523, the wth second conductive block 521 and the w+mth second conductive block 521 are electrically connected, so that the same-phase currents are reversed in the longitudinal direction when the flexible circuit board winding 5 is unfolded. Figure 5As shown in FIG, the first second conductive block 521 from right to left is electrically connected to the third second conductive block 521, allowing the Sin phase current to flow from right to left. The second second conductive block 521 from right to left is electrically connected to the fourth second conductive block 521, allowing the Cos phase current to flow from left to right. This allows each first conductive block 511 and each second conductive block 521 to be utilized to flow current, thereby improving utilization. Furthermore, the input terminals of the m phase currents are arranged side by side with the first m first conductive blocks 511 of the 2m first conductive blocks protruding from the nth routing layer 51 relative to the n+1th routing layer 52, and the output terminals of the m phase currents are arranged side by side with the last m first conductive blocks 511. This spatially places the input and output pads of the flexible circuit board winding 5 relatively close together, facilitating wiring and facilitating the input and output design of the flexible circuit board winding 5. Furthermore, the sequential arrangement of the input and output terminals of the m phase currents reduces the probability of short circuits compared to an alternating arrangement.

[0055] Of course, to avoid short-circuiting between the Sin phase current and the Cos phase current, the second second conductive block 521 and the fourth second conductive block 521 from right to left can be connected via a metal component provided on the (n+1)th routing layer 52, and the first second conductive block 521 and the third second conductive block 521 from right to left can be connected via a metalized via and a metal component provided on the (n)th routing layer 51. Alternatively, the second second conductive block 521 and the fourth second conductive block 521 from right to left can be connected via a metalized via and a metal component provided on the (n)th routing layer 51, and the first second conductive block 521 and the third second conductive block 521 from right to left can be connected via a metalized via and a metal component provided on the (n+1)th routing layer 52.

[0056] The above description is made using the nth routing layer 51 and the n+1th routing layer 52 as an example. In other embodiments, the same flexible circuit board winding 5 may also include the pth routing layer and the p+1th routing layer, where p=n+2. In this case, in order to achieve the flow of the current path, after the phase current flows back to the left side of the n+1th routing layer 52, it can be electrically connected to the protruding area on the left side of the pth routing layer through the second conductive block 521 of the n+1th routing layer 52, and then the circuit between the pth routing layer and the p+1th routing layer is connected with reference to the routing rules of the nth routing layer 51 and the n+1th routing layer 52. When the flexible circuit board winding 5 includes more layers of routing layers, the above embodiment can be referred to for implementation.

[0057] In each of the above embodiments, the flexible circuit board winding 5 is wound around the rotor core 2 in K turns, where K is greater than or equal to 1; in the radially outward direction of the rotor core, in the first to Kth turns, the number of first conductive blocks in each turn is equal to the number of second conductive blocks, and the number of first conductive blocks in each turn is equal to the number of motor phases × the number of pole pairs × 2 × the number of bars per phase per pole - the number of motor phases × the number of bars per phase per pole × 2.

[0058] In some embodiments, the rotor core 2 includes multiple layers of concentrically arranged annular silicon steel sheets, which helps reduce the motor's eddy current losses and, in turn, the motor's drag torque. In other words, by stacking multiple layers of annular silicon steel sheets to form the rotor core 2, the inner ring space of the rotor core 2 can be used to arrange motor components or configure mechanical or electrical components on the equipment side of the permanent magnet synchronous motor. This improves the compactness of the permanent magnet synchronous motor and the associated equipment side, and facilitates miniaturization of the permanent magnet synchronous motor.

[0059] In some embodiments, the S-pole magnet 4 and the N-pole magnet 3 have the same shape and corresponding size parameters; Figure 6 As shown, the cross-section of the S-pole magnet 4 includes a rectangle and an isosceles trapezoid, with the lower base of the isosceles trapezoid connecting to the long side of the rectangle. The S-pole magnet is symmetrical. The cross-sectional shape and dimensional parameters of the N-pole magnet are identical to those of the S-pole magnet 4. This structural design can reduce the magnetic flux density distortion of the permanent magnet synchronous motor. The corners of the S-pole magnet 4 and the N-pole magnet 3 are both chamfered to reduce scratching.

[0060] The present disclosure also provides a gyro north finder, comprising a permanent magnet synchronous motor as described in any of the aforementioned embodiments. The application of a permanent magnet synchronous motor using radial magnetic flux to a gyro north finder not only improves space utilization by utilizing the inner ring space of the rotor core 2 and reduces the motor size, thus meeting the requirements of a miniaturized gyro north finder, but also offers a simple motor structure, improved dynamic and static performance, and a direct drive configuration, eliminating the need for a speed reducer, saving space, and ensuring the motor's accuracy and reliability.

[0061] Based on the technical solution disclosed in the present invention, a design method for a permanent magnet synchronous motor is also provided, which is applied to the permanent magnet synchronous motor described in any of the above embodiments. Figure 7 As shown, the design method includes the following steps:

[0062] In step 701, the outer diameter of the stator core, the inner diameter of the rotor core, and the motor torque are determined based on the size of the components required to be assembled on the inner ring of the rotor core, the size of the components to be assembled on the outer ring of the stator core, and the load capacity requirements of the permanent magnet synchronous motor.

[0063] In step 702, whether there are brushes, the motor power supply waveform, the number of motor phases and the driving mode are determined based on the motor size and performance requirements of the permanent magnet synchronous motor.

[0064] In this embodiment, a permanent magnet synchronous motor is used in a gyro north finder as an example. To improve space utilization and considering the uncontrollable influence of the axial magnetic attraction of the disc motor on the bearing preload state, a radial flux structure is selected. Since the speed required by the gyro north finder is generally not high, the reducer requires a certain volume and there is a transmission gap problem, which reduces the accuracy and reliability of the motor, so a direct drive method is selected. Although the structure and control of the brushless DC motor are simple, there are friction problems, which increase system noise and reduce lifespan, so a brushless solution is selected. Common brushless direct current motors (BLDC) and permanent magnet synchronous motors (PMSM) are both brushless structures. They use sinusoidal power supply instead of the square wave power supply of the BLDC, eliminating torque ripple during commutation, making the operation more stable and having better static and dynamic characteristics. In addition, the permanent magnet synchronous motor can be powered by a DC power supply in terms of control, making it convenient to use.

[0065] Based on this, it was determined that a radial flux two-phase permanent magnet synchronous motor with a brushless structure, sinusoidal power supply, and direct drive was used. Permanent magnet synchronous motors are powered by sinusoidal current. Compared to brushless DC motors, they omit slip rings and brushes, resulting in a simpler structure and eliminating torque ripple during commutation. This results in smoother operation and improved reliability. Their compact size makes them widely applicable in miniaturized carrier scenarios.

[0066] In step 703, the magnetic flux density waveform distortion of the permanent magnet synchronous motor is used as the optimization objective function, and the outer diameter size of the stator core, the inner diameter size of the rotor core and the actual processing and manufacturing requirements are used as constraints of the optimization parameters. Within the value range of the stator core thickness, the value range of the rotor core thickness, the value range of the air gap thickness, the value range of the winding thickness, the value range of the magnet shape and the value range of each magnet size parameter, a static magnetic field simulation is performed on the three-dimensional model of the permanent magnet synchronous motor, and the optimal solution of the stator core thickness, the optimal solution of the rotor core thickness, the optimal solution of the air gap thickness value, the optimal solution of the winding thickness, the optimal solution of the magnet shape and the optimal solution of each magnet size are obtained through traversal optimization.

[0067] In the embodiments disclosed herein, due to the motor's inherent structure, the magnetic flux density waveform cannot achieve an ideal sinusoidal waveform. The various harmonics it contains cause torque fluctuations, resulting in motor noise and vibration, low motor efficiency, high power consumption, and reduced lifespan. Furthermore, torque fluctuations can affect subsequent high-precision motor control. This paper introduces distortion to quantitatively describe the maximum degree of distortion of the air gap magnetic flux density waveform relative to a standard sine wave.

[0068]

[0069] Among them, r is the calculated air gap flux density, s is the standard sine function value, A s is the amplitude of the standard sine wave. The smaller the maximum distortion, the closer the magnetic flux density waveform is to the sine wave. Therefore, the magnetic flux density waveform distortion can be used as the optimization objective function.

[0070] For example, actual processing and manufacturing requirements include: the thickness of the stator core 1 and the rotor core 2 must be as large as possible within the allowable range to prevent deformation during processing; the magnet thickness must be at least 1.2mm to ensure that the performance of the processed magnets meets the nominal performance; the depth of the magnet embedded in the stator core 1 must be at least half the magnet thickness to reduce magnetic leakage; the air gap thickness must be at least 0.3mm to prevent the air gap thickness from being too small due to processing errors. A too small air gap may cause friction between the stator core 1 and the rotor core 2, which is not conducive to motor heat dissipation; the stator core is made of DT4 material, and its magnetic flux density cannot exceed the threshold to prevent magnetic saturation and motor overheating. Of course, there may be other actual processing and manufacturing requirements, which will not be detailed here.

[0071] In this embodiment, multiple parameters such as stator core thickness, rotor core thickness, air gap thickness, winding thickness, magnet shape and various magnet size parameters can be optimized in sequence. When the optimal solution is obtained for the previous parameter, another parameter is optimized.

[0072] For example, taking magnet selection as Figure 6 Taking the structure shown in as an example, the optimized parameters of the magnet include the circumferential width L_width of the magnet, the radial thickness L_thick of the magnet, the thickness L_insert of the magnet embedded in the stator core, the circumferential width L_incW of the inclined plane, the radial thickness L_incT of the inclined plane, and the fillet radius at the corners. On the basis of setting the axial length, radial thickness, rotor core thickness, stator core thickness, air gap thickness, winding thickness, thickness of the magnet embedded in the stator core, radial thickness of the inclined plane, circumferential width of the inclined plane, and fillet radius, only the relationship between the circumferential width L_width of the magnet and the distortion of the average magnetic flux density of the winding is considered, as shown in the figure below: Figure 8As shown in the figure, the relationship between the two forms a V-shape, with the magnetic flux density distortion reaching a minimum within the simulation range, corresponding to a circumferential magnet width L_width of 3.18 mm. After determining the value of the magnet circumferential width L_width parameter, other shape parameters such as the radial thickness of the inclined surface, the circumferential width of the inclined surface, and the fillet radius were optimized to obtain the final three-dimensional structural parameters of the motor.

[0073] For another example, multiple possible combinations can be obtained within the parameter range of the stator core thickness, rotor core thickness, air gap thickness, winding thickness, magnet shape, magnet circumferential width L_width, magnet radial thickness L_thick, magnet thickness embedded in the core L_insert, inclined surface circumferential width L_incW, inclined surface radial thickness L_incT and fillet radius at corners, and the optimal value of each parameter can be obtained by traversing the multiple possible combinations.

[0074] In this technical solution, the permanent magnet synchronous motor is divided into a stator and a rotor for modular and standardized design. This not only allows the permanent magnet synchronous motor to be precisely customized according to needs, but also the programmed design method improves design efficiency and facilitates mass production.

[0075] In some other embodiments, Figure 9 As shown, the design method also includes steps 704 and 705. In step 704, a flexible circuit board pattern with positioning lines is generated based on the optimal winding thickness solution, the optimal rotor core thickness solution, and winding parameters. The positioning lines are used to locate the position of the conductive blocks after the flexible circuit board winding is wound around the rotor core. The winding parameters include the number of conductive blocks per pole and phase, the number of winding turns, the insulating gap between conductive blocks, the axial margin of conductive blocks, the circumferential margin of conductive blocks, the inner diameter of metalized vias, the outer diameter of metalized vias, the center spacing of metalized vias, the circumferential margin of metalized vias, the axial margin of metalized vias, and the spacing angle of the positioning lines. In step 705, the flexible circuit board pattern is post-processed to obtain a flexible circuit board winding for processing. The post-processing includes setting design rules, batch copper plating of the conductive block pattern, adding a mechanical layer outline, and design rule checking. The generation of flexible circuit board windings based on this programmatic design can greatly improve design efficiency. The axial direction in the above-mentioned dimension definitions refers to the axial direction of the rotor core 2 , and the circumferential direction refers to the circumferential direction of the rotor core 2 .

[0076] The flexible circuit board winding, manufactured using a multi-layer flexible PCB, can be wound around the rotor core. It offers advantages such as light weight, compact size, and ease of programmable design and mass production. To maximize the effective conductor area and reduce the complexity of the winding structure, a two-phase winding is employed with the conductive blocks arranged at an angle. To ensure alignment of each conductive block around the rotor core, alignment lines are designed on the surface of the flexible circuit board winding, with adjacent alignment lines spaced 360° apart.

[0077] Other embodiments of the present disclosure will readily occur to those skilled in the art after considering the specification and practicing the disclosure herein. This disclosure is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the present disclosure being indicated by the following claims.

[0078] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes can be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A permanent magnet synchronous motor, characterized in that: include: A stator, the stator comprising a stator core, an N-pole magnet and an S-pole magnet, wherein the N-pole magnet and the S-pole magnet are alternately arranged on an inner side of the stator core along a circumferential direction of the stator core; A rotor, the rotor comprising a rotor core and a flexible circuit board winding, the rotor core and the stator core being concentrically arranged, the rotor core being located inside the stator core, and the flexible circuit board winding being arranged around the outside of the rotor core; The flexible circuit board winding includes routing layers stacked along the thickness direction of the flexible circuit board winding when the flexible circuit board winding is unfolded, each routing layer includes a conductive block having a parallelogram-shaped planar shape, the short sides of the conductive block are arranged along the length direction of the flexible circuit board winding when the flexible circuit board winding is unfolded, and the multiple conductive blocks are spaced and insulated along the length direction of the flexible circuit board winding when the flexible circuit board winding is unfolded; The flexible circuit board winding includes an nth routing layer and an n+1th routing layer, where n is an odd number; the nth routing layer includes a plurality of first conductive blocks, and the n+1th routing layer includes a plurality of second conductive blocks; When the flexible circuit board winding is in an unfolded state, the plurality of second conductive blocks are divided into an overlapping area and a first protruding area, the overlapping area is located below the nth wiring layer, and the first protruding area is partially protruded relative to the nth wiring layer; In the overlapping area of ​​the (n+1)th routing layer and the (n)th routing layer, the same phase current alternately flows through the first conductive block and the second conductive block; The nth routing layer is provided with a second protruding area protruding relative to the n+1th routing layer, and the second protruding area is provided with 2m first conductive blocks, the first m first conductive blocks correspond one-to-one to the m different-phase input currents, and the last m first conductive blocks correspond one-to-one to the m different-phase output currents, where m is the number of winding phases and is greater than 1; Among the 2m second conductive blocks in the first protruding area, the wth second conductive block and the w+mth second conductive block are electrically connected, so that the same-phase currents are reversed in the length direction of the flexible circuit board winding when it is unfolded.

2. The permanent magnet synchronous motor according to claim 1, characterized in that: The long sides of the parallelogram are all inclined relative to the width direction of the flexible circuit board winding when it is unfolded; The number of layers of the routing layers is even, and in the stacking direction of the routing layers, the long sides of the conductive blocks of the routing layers with odd numbers have the same inclination direction and equal inclination angles, and the long sides of the conductive blocks of the routing layers with even numbers have the same inclination direction and equal inclination angles; The inclination direction of the long sides of the conductive blocks of the routing layers with even numbers is opposite to the inclination direction of the long sides of the conductive blocks of the routing layers with odd numbers.

3. The permanent magnet synchronous motor according to claim 1, characterized in that: The flexible circuit board winding further includes metallized vias, each of which connects a single first conductive block and a single second conductive block.

4. The permanent magnet synchronous motor according to claim 1, characterized in that: The flexible circuit board winding is wound around the rotor core K times, where K is greater than or equal to 1; The number of conductive blocks in the multiple routing layers of all flexible circuit board windings is equal.

5. The permanent magnet synchronous motor according to claim 1, characterized in that: The rotor core comprises multiple layers of concentrically arranged annular silicon steel sheets; and / or, The S-pole magnet and the N-pole magnet have the same planar shape and the same corresponding size parameters; the planar shape of the S-pole magnet includes a rectangle and an isosceles trapezoid, and the lower base of the isosceles trapezoid is connected to the long side of the rectangle.

6. The permanent magnet synchronous motor according to claim 1, characterized in that: The corners of the S-pole magnet and the N-pole magnet are both provided with arc chamfers; and / or The flexible circuit board winding is a two-phase winding.

7. A gyro north finder, characterized in that: The method comprises the permanent magnet synchronous motor according to any one of claims 1 to 6.

8. A design method for a permanent magnet synchronous motor, characterized in that: Applied to the permanent magnet synchronous motor according to any one of claims 1 to 6, the design method comprises: Determine the stator core outer diameter, rotor core inner diameter, and motor torque based on the size of components required to be assembled on the rotor core inner ring, the size of components assembled on the stator core outer ring, and the load capacity requirements of the permanent magnet synchronous motor; Based on the motor size and performance requirements of the permanent magnet synchronous motor, determine whether it has brushes, the motor power supply waveform, the number of motor phases and the drive mode; The magnetic flux density waveform distortion of the permanent magnet synchronous motor is used as the optimization objective function, and the outer diameter size of the stator core, the inner diameter size of the rotor core and the actual processing and manufacturing requirements are used as the constraints of the optimization parameters. Within the value range of the stator core thickness, the value range of the rotor core thickness, the value range of the air gap thickness, the value range of the winding thickness, the value range of the magnet shape and the value range of each magnet size parameter, the static magnetic field simulation is performed on the three-dimensional model of the permanent magnet synchronous motor, and the traversal optimization is performed to obtain the optimal solution of the stator core thickness, the optimal solution of the rotor core thickness, the optimal solution of the air gap thickness value, the optimal solution of the winding thickness, the optimal solution of the magnet shape and the optimal solution of each magnet size.

9. The method for designing a permanent magnet synchronous motor according to claim 8, further comprising: Generate a flexible circuit board graphic with positioning lines based on the optimal solution for the winding thickness, the optimal solution for the rotor core thickness, and the winding parameters. The positioning lines are used to locate the position of the conductive blocks after the flexible circuit board winding is wound around the rotor core. The winding parameters include the number of conductive blocks per pole and per phase, the number of winding turns, the insulating gap between the conductive blocks, the axial margin of the conductive blocks, the circumferential margin of the conductive blocks, the inner diameter of the metallized vias, the outer diameter of the metallized vias, the center-to-center spacing of the metallized vias, the circumferential margin of the metallized vias, the axial margin of the metallized vias, and the spacing angle of the positioning lines. The flexible circuit board pattern is post-processed to obtain a flexible circuit board winding for processing, wherein the post-processing includes setting design rules, batch copper plating of conductive block patterns, adding mechanical layer outlines and design rule checking.

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