A high-performance, high-speed surface-mount permanent magnet synchronous motor with sinusoidal segmentation of permanent magnets

Abstract

The present invention discloses a high-performance, high-speed, surface-mounted permanent magnet synchronous motor with sinusoidal segmentation of permanent magnets. The stator core portion of the motor comprises an amorphous alloy portion and a silicon steel portion. The low high-frequency loss characteristics of the amorphous alloy and the high saturation magnetic density of silicon steel are utilized to reduce the high-frequency loss of the stator core portion while ensuring that the magnetic density in the amorphous alloy material does not exceed the saturation magnetic density of the amorphous alloy. A stepped arc-shaped notch is provided on the outer surface portion corresponding to each magnetic pole of the rotor core, and a group of segmented permanent magnets are installed in the stepped arc-shaped notch. The central permanent magnet is the thickest and the thickness on both sides gradually decreases in a sinusoidal arrangement, so that the air gap magnetic flux density corresponding to each magnetic pole decreases sequentially from the pole symmetry axis outward, making the air gap magnetic density closer to a sine wave, effectively reducing high-frequency harmonics, reducing the total harmonic content of the air gap magnetic density and the radial electromagnetic force density of the air gap, and thereby reducing the torque pulsation and vibration noise of the motor.

Description

Technical Field

[0001] The present invention relates to the technical field of permanent magnet synchronous motors, and in particular to a high-performance, high-speed surface-mounted permanent magnet synchronous motor with sinusoidal segmented permanent magnets. Background Art

[0002] High-speed surface-mounted permanent magnet synchronous motors are an important specialty motor. Current research on high-speed motors focuses on maximizing operating speeds to increase power density. Compared to motors operating at normal speeds, increasing rotor speeds leads to increasingly stringent requirements for torque ripple and vibration noise. High-speed operation introduces higher-frequency harmonics into the stator and rotor cores, leading to a sharp increase in stator core losses and high-frequency eddy current losses in the rotor core. This not only increases the stator and rotor temperature rise, reducing mechanical strength, but also significantly increases the risk of permanent magnet demagnetization. Excessive localized temperature rise can also reduce the rotor's ultimate stress.

[0003] Because the permanent magnets are located on the rotor surface, high-speed surface-mounted permanent magnet synchronous motors (SPMSMs) utilize their permanent magnets to the fullest extent, resulting in greater torque output and a wider constant-torque speed range. However, the low magnetic field weakening capability of SPMSMs narrows their constant-power speed range. The interaction between the stator slots and the rotor permanent magnetic field generates cogging torque and torque pulsation. Large cogging torque and torque pulsation can affect the smooth operation of electric vehicles, especially at high speeds. High torque pulsation increases wear on the rotor core and bearings, reducing the service life of the SPMSM. Furthermore, cogging torque and torque pulsation can cause significant vibration and noise, seriously impacting the comfort of electric vehicles.

[0004] Patent CN115694014A proposes a motor rotor core segmentation and a motor rotor with a rotor core assembly. This approach reduces cogging torque and torque pulsation by skewing the rotor segments. The rotor is divided into five segments, each offset by an angle. The thickness of the rotor segment laminations at both ends is less than that of the three middle rotor segments. By utilizing the phase difference between the permanent magnet segments, the cogging torque and electromagnetic torque waveforms compensate for each other, reducing cogging torque and torque pulsation. However, the manufacturing process is complex, and the mechanical strength of the connection between the rotor segments is weak. During high-speed operation, the rotor segments are prone to slippage. Patent CN110649722A proposes a motor with an integrated amorphous alloy and silicon steel stator core. The stators are made of amorphous alloy and silicon steel, and the two stators are coaxially connected. The amorphous alloy stator has extremely low high-frequency loss, which can effectively reduce the iron loss of the motor during high-speed operation, thereby improving high-speed operation efficiency. However, the magnetic permeability and saturation flux density of amorphous alloy materials are lower than those of silicon steel, which limits the improvement of torque. At the same time, stator flux saturation will bring about large torque pulsation and radial electromagnetic force, generating vibration noise, affecting the ride comfort of electric vehicles.

[0005] In summary, when a traditional high-speed surface-mounted permanent magnet synchronous motor runs at high speed, the high-frequency current excites high-frequency magnetic flux in the stator core, resulting in large high-frequency losses in the stator core, causing the temperature rise of the motor to be too high when running at high speed; at the same time, when a traditional high-speed surface-mounted permanent magnet synchronous motor runs at high speed, the high-frequency harmonic content in the air gap magnetic flux is large and the distortion is serious, thereby generating a large radial electromagnetic force density in the stator core, and the torque pulsation and vibration noise are relatively serious. Summary of the Invention

[0006] To address the deficiencies of the prior art, the present invention provides a high-performance, high-speed, surface-mount permanent magnet synchronous motor with sinusoidal segmentation of permanent magnets. The motor utilizes a method of combining amorphous alloy and silicon steel materials to manufacture the stator structure of the high-performance, high-speed surface-mount permanent magnet synchronous motor. By utilizing the extremely low high-frequency loss of amorphous alloys and the high magnetic permeability and high saturation magnetic flux density of silicon steel, the high-speed motor's stator high-frequency loss is reduced, thereby improving efficiency under high-speed operation. At the same time, a stepped arc-shaped notch is provided on the outer surface portion corresponding to each magnetic pole of the rotor core, and a group of segmented permanent magnets are installed in the stepped arc-shaped notch. The central permanent magnet has the largest thickness, and the thickness gradually decreases on both sides in a sinusoidal arrangement. This arrangement allows the air gap magnetic flux density corresponding to each magnetic pole to decrease outward from the pole symmetry axis, making the air gap magnetic flux density closer to a sine wave, reducing the total harmonic content of the air gap magnetic flux density and the radial electromagnetic force density of the air gap, thereby reducing torque pulsation and vibration noise.

[0007] The technical solution adopted by the present invention to solve the technical problem is: designing a high-performance, high-speed, surface-mounted permanent magnet synchronous motor with sinusoidal segmentation of permanent magnets, characterized in that the motor includes a stator core portion, windings, a rotor core, a rotating shaft, permanent magnets, and a sheath; the stator core portion includes an amorphous alloy portion and a silicon steel portion, the amorphous alloy portion comprising an annular stator yoke made of laminated and bonded amorphous alloy material and N first stator teeth connected to the inner side of the annular stator yoke, and the silicon steel portion comprising N second stator teeth made of laminated and bonded silicon steel, the end faces of the first stator teeth matching the dimensions of the top end faces of the second stator teeth, and the two being fixed together by bonding to form N stator teeth; windings are wound around the N stator teeth;

[0008] The rotor core is located inside the stator core, and the two have the same width and are positioned opposite each other. An identical stepped arc-shaped notch is provided on the outer surface corresponding to each magnetic pole of the annular rotor core. The middle notch of the stepped arc-shaped notch has the greatest depth, and the two sides are symmetrical, with the step position of the stepped arc-shaped notch gradually decreasing from the two sides to the middle. A group of permanent magnets matching the notch are provided in each stepped arc-shaped notch, and the outer peripheral end surfaces of the permanent magnets in all stepped arc-shaped notches form a ring. Adjacent permanent magnets and the permanent magnets and the rotor core are fixed by bonding. A sheath is mounted on the outer peripheral end surfaces of all permanent magnets, so that all permanent magnets and the rotor core are fixed as a whole. The rotor core is fixed to the rotating shaft through its central through hole.

[0009] Each permanent magnet in a group of permanent magnets within each stepped arc-shaped gap has the same width, the magnetization direction of each permanent magnet is perpendicular to its outer peripheral end face, and the permanent magnets in each group of permanent magnets are arranged alternately with north poles and south poles along the circumferential direction of the rotor core. The arrangement of the permanent magnets in different groups is the same;

[0010] An air gap is left between the end faces of the stator teeth of the stator core and the sheath; the sheath on the peripheral end face of the permanent magnet is made of non-magnetic conductive material.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: the stator core part of the motor designed by the present invention includes an amorphous alloy part and a silicon steel part, and utilizes the characteristics of low high-frequency loss of amorphous alloy and the advantage of high saturation magnetic density of silicon steel to reduce the high-frequency loss of the stator core part while ensuring that the magnetic density in the amorphous alloy material does not exceed the saturation magnetic density of the amorphous alloy; a stepped arc-shaped notch is provided on the outer surface part corresponding to each magnetic pole of the rotor core, and a group of segmented permanent magnets are installed in the stepped arc-shaped notch, and the central permanent magnet has the largest thickness and the thickness on both sides gradually decreases in a sinusoidal arrangement, so that the air gap magnetic flux density corresponding to each magnetic pole decreases from the pole symmetry axis outward in sequence, making the air gap magnetic density closer to a sine wave, effectively reducing high-frequency harmonics, reducing the total harmonic content of the air gap magnetic density and the radial electromagnetic force density of the air gap, and thereby reducing the torque pulsation and vibration noise of the high-speed permanent magnet synchronous motor during high-speed operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a principle simulation diagram of an embodiment of the present invention's high-performance, high-speed, surface-mounted permanent magnet synchronous motor with sinusoidal segmentation.

[0013] Figure 2 A schematic diagram of the assembly of a rotor core and permanent magnets of an embodiment of a high-performance, high-speed, surface-mounted permanent magnet synchronous motor with sinusoidal segmentation of the present invention.

[0014] Figure 3A schematic diagram of the assembly of the rotor core and permanent magnets of another embodiment of a high-performance, high-speed, surface-mounted permanent magnet synchronous motor with sinusoidal segmentation of the present invention.

[0015] Figure 4 The figure shows a schematic diagram comparing the air gap flux density waveforms of a traditional high-speed surface-mount permanent magnet synchronous motor (curve A) and the motor of the present invention when the permanent magnet is sinusoidally divided into 3 segments (curve B), the permanent magnet is sinusoidally divided into 5 segments (curve C), the permanent magnet is sinusoidally divided into 7 segments (curve D), and the permanent magnet is sinusoidally divided into 9 segments (curve E).

[0016] Figure 5 The figure shows a comparative diagram of harmonic analysis of the air gap flux density waveforms of a conventional high-speed surface-mount permanent magnet synchronous motor (curve A) and the motor of the present invention when the permanent magnet is sinusoidally divided into 3 segments (curve B), the permanent magnet is sinusoidally divided into 5 segments (curve C), the permanent magnet is sinusoidally divided into 7 segments (curve D), and the permanent magnet is sinusoidally divided into 9 segments (curve E).

[0017] Figure 6 The figure shows a schematic comparison of the back electromotive force waveforms of a traditional high-speed surface-mount permanent magnet synchronous motor (curve A) and the motor of the present invention when the permanent magnet is sinusoidally divided into 3 segments (curve B), the permanent magnet is sinusoidally divided into 5 segments (curve C), the permanent magnet is sinusoidally divided into 7 segments (curve D), and the permanent magnet is sinusoidally divided into 9 segments (curve E).

[0018] Figure 7 The figure shows a comparative diagram of the harmonic analysis of the back electromotive force waveforms of a conventional high-speed surface-mount permanent magnet synchronous motor (curve A) and the motor of the present invention when the permanent magnet is sinusoidally divided into 3 segments (curve B), the permanent magnet is sinusoidally divided into 5 segments (curve C), the permanent magnet is sinusoidally divided into 7 segments (curve D), and the permanent magnet is sinusoidally divided into 9 segments (curve E).

[0019] Figure 8 The figure shows a schematic diagram comparing the cogging torque of a traditional high-speed surface-mount permanent magnet synchronous motor (curve A) and the motor of the present invention when the permanent magnet is sinusoidally divided into 3 segments (curve B), the permanent magnet is sinusoidally divided into 5 segments (curve C), the permanent magnet is sinusoidally divided into 7 segments (curve D), and the permanent magnet is sinusoidally divided into 9 segments (curve E).

[0020] Figure 9 Schematic diagram showing the peak-to-peak value of the cogging torque (curve A) of the motor of the present invention at different numbers of permanent magnet segments and the torque ripple (curve B) at different numbers of permanent magnet segments.

[0021] Figure 10 The figure shows a comparison of the maximum vibrations of a conventional high-speed surface-mount permanent magnet synchronous motor (curve A) and a motor of the present invention with sinusoidal permanent magnets divided into 7 segments (curve B) at 0-5000 Hz.

[0022] Figure 11The figure shows a comparison of the maximum sound pressure levels at a distance of 50 mm from the stator surface between 0-5000 Hz for a conventional high-speed surface-mounted permanent magnet synchronous motor (curve A) and a motor of the present invention with sinusoidal permanent magnets divided into 7 segments (curve B). DETAILED DESCRIPTION

[0023] The accompanying drawings referenced in the present invention should be understood as exemplary examples within the scope of the claims of the present invention, and are intended to provide guidance to those skilled in the art for implementing corresponding technical solutions, rather than to limit the present invention. The present invention will be further described below with reference to the accompanying drawings.

[0024] The present invention provides a high-performance, high-speed, surface-mounted permanent magnet synchronous motor (hereinafter referred to as a motor) with sinusoidal segmentation of permanent magnets. The motor comprises a stator core portion, windings, a rotor core, a rotating shaft, permanent magnets, and a sheath. The stator core portion comprises an amorphous alloy portion and a silicon steel portion. The amorphous alloy portion comprises an annular stator yoke made of laminated and bonded amorphous alloy materials and comprises N first stator teeth connected to the inner side surface of the annular stator yoke. The silicon steel portion comprises N second stator teeth made of laminated and bonded silicon steel. The end faces of the first stator teeth match the dimensions of the top end faces of the second stator teeth, and the two are fixed together by bonding to form N stator teeth. Windings are wound around the N stator teeth.

[0025] The rotor core is located inside the stator core, and the two have the same width (i.e., length along the axial direction) and are positioned opposite each other. An identical stepped arc-shaped notch is provided on the outer surface corresponding to each magnetic pole of the annular rotor core. The middle notch of the stepped arc-shaped notch has the greatest depth, and the two sides are symmetrical, with the step position of the stepped arc-shaped notch gradually decreasing from both sides to the middle. A group of matching permanent magnets is provided in each stepped arc-shaped notch, and the outer peripheral end surfaces of the permanent magnets in all stepped arc-shaped notches form a ring. Adjacent permanent magnets and the permanent magnets and the rotor core are fixed by bonding. A sheath is mounted on the outer peripheral end surfaces of all permanent magnets, so that all permanent magnets and the rotor core are fixed as a whole. The rotor core is fixed to the rotating shaft through its center through-hole.

[0026] The thickness of each permanent magnet in a group of permanent magnets within each stepped arc-shaped gap is not less than 2 mm, and the widths are the same. The magnetization direction of each permanent magnet is perpendicular to its outer peripheral end face (i.e., along the radial direction of the rotor core), and the permanent magnets in each group of permanent magnets are arranged alternately with N poles and S poles along the circumferential direction of the rotor core. The arrangement of the permanent magnets in different groups is the same.

[0027] An air gap is left between the end face of the stator teeth of the stator core part and the sheath, and the air gap is between 0.5mm and 0.8mm.

[0028] The sheath on the peripheral end surface of the permanent magnet is a fiber binding belt sheath made of non-magnetic carbon fiber material.

[0029] The innovation of the present invention lies in the stator core and rotor core structures. Conventional high-speed surface-mounted permanent magnet synchronous motors use only silicon steel for their stator cores, which produces high-frequency magnetic flux during high-speed operation, resulting in significant losses in the stator core. The present invention, however, employs a high-performance, high-speed surface-mounted permanent magnet synchronous motor with sinusoidal segmentation, using amorphous alloy materials for the stator yoke and the associated stator teeth, and silicon steel for the stator tooth tips and the associated stator teeth. This utilizes the extremely low high-frequency losses of amorphous alloys and the high magnetic permeability and saturation flux density of silicon steel to reduce motor losses while ensuring that the flux density of each stator core component does not exceed the saturation flux density. The permanent magnets of traditional high-speed surface-mounted permanent magnet synchronous motors are placed on the rotor surface without segmentation, and the air gap magnetic flux waveform is close to a square wave, which will generate large torque pulsation and vibration noise when running at high speed. The high-performance high-speed surface-mounted permanent magnet synchronous motor with sinusoidal segmentation of permanent magnets of the present invention divides the permanent magnet under each pole into several segments, and the thickness decreases from the center of the pole outward, thereby increasing the sinusoidalization of the air gap magnetic flux and reducing the torque pulsation and vibration noise when the motor runs at high speed.

[0030] Example 1

[0031] This embodiment provides a high-performance, high-speed, surface-mount permanent magnet synchronous motor with sinusoidal segmentation of permanent magnets. Figure 1-2 The motor includes a stator core portion, a three-phase symmetrical winding 3, a rotor core 6, a rotating shaft 11, a permanent magnet, and a sheath 4; the stator core portion includes an amorphous alloy portion 1 and a silicon steel portion 2, the amorphous alloy portion 1 is an annular stator yoke made of amorphous alloy material laminated and bonded, and 12 first stator teeth connected to the inner side of the annular stator yoke, the silicon steel portion 2 is 12 second stator teeth made of silicon steel laminated and bonded, the end face of the first stator tooth matches the size of the top end face of the second stator tooth and the two are fixed together by bonding to form 12 stator teeth; the 12 stator teeth are wound with a three-phase symmetrical winding 3, which can generate a rotating magnetic field, and the magnetic field interacts with the rotor core 6 to generate torque;

[0032] The rotor core 6 is located inside the stator core, and the two have the same width (i.e., length along the axial direction) and are positioned opposite each other; four pairs of magnetic poles are provided on the rotor core 6, and an identical stepped arc-shaped notch is opened on the outer surface corresponding to each magnetic pole of the annular rotor core 6; the middle notch of the stepped arc-shaped notch has the largest notch depth, and the two sides are symmetrical, and the step position of the stepped arc-shaped notch gradually decreases from the two sides to the middle.

[0033] The central notch of the stepped arcuate notch is flanked by three steps. Each notch houses a matching set of permanent magnets. The outer periphery of the permanent magnets within each notch forms a ring. Adjacent permanent magnets and the rotor core 6 are secured together by bonding. A sheath is fitted over the outer periphery of all permanent magnets, securing them to the rotor core as a single unit. The rotor core 6 is secured to the rotating shaft 11 via its central through-hole, allowing it to rotate synchronously with the shaft 11.

[0034] A group of permanent magnets arranged in a stepped arc-shaped gap includes 7 permanent magnets, that is, the permanent magnets are sinusoidally divided into 7 segments, specifically a central permanent magnet 7 of a sinusoidally segmented permanent magnet, a second permanent magnet 8 of a sinusoidally segmented permanent magnet, a third permanent magnet 9 of a sinusoidally segmented permanent magnet, and a fourth permanent magnet 10 of a sinusoidally segmented permanent magnet.

[0035] The width of each permanent magnet is the same as the width of the stepped arc-shaped notch on the outer surface of the rotor. The central permanent magnet 7 of the sinusoidal permanent magnet segment is placed in the middle notch. The second permanent magnets 8 of the two sinusoidal permanent magnet segments are respectively placed on both sides of the central permanent magnet 7 of the sinusoidal permanent magnet segment. The third permanent magnets 9 of the two sinusoidal permanent magnet segments are respectively placed on both sides of the second permanent magnet 8 of the sinusoidal permanent magnet segment. The fourth permanent magnets 10 of the two sinusoidal permanent magnet segments are respectively placed on both sides of the third permanent magnet 9 of the sinusoidal permanent magnet segment. This structure makes the air gap magnetic density wave of the motor closer to a sine wave, and the torque pulsation and vibration noise are lower during high-speed operation.

[0036] The thickness of the permanent magnets in each group of permanent magnets in the stepped arc-shaped notch is not less than 2 mm, the magnetization direction of each permanent magnet is perpendicular to its outer peripheral end face (i.e., along the radial direction of the rotor core), and the permanent magnets in each group of permanent magnets have their N poles and S poles arranged alternately along the circumferential direction of the rotor core, and the arrangement of the permanent magnets in different groups is the same.

[0037] An air gap 5 is left between the end face of the stator teeth of the stator core and the sheath, and the air gap 5 is between 0.5 mm and 0.8 mm.

[0038] In this embodiment, the rotor core has four pairs of magnetic poles, and the permanent magnet on each magnetic pole is sinusoidally divided into seven segments. The width of each segment of the permanent magnet is the same. The fiber binding belt sheath is wrapped around the outside of the permanent magnet to fix it. The thickness of the fourth segment of the permanent magnet 10 of the sinusoidal segmentation is greater than 2 mm.

[0039] Example 2

[0040] This embodiment provides a high-performance, high-speed, surface-mounted permanent magnet synchronous motor with sinusoidally segmented permanent magnets. The structures of the various parts of the motor in this embodiment are the same as those in Example 1, except that a group of permanent magnets under each magnetic pole of the rotor core 12 in this embodiment includes 5 permanent magnets, that is, the permanent magnets are sinusoidally divided into 5 segments. Correspondingly, two steps are provided on both sides of the middle gap of the stepped arc-shaped gap of the rotor core 12.

[0041] like Figure 3 This is a schematic diagram of the assembly of the rotor core and the permanent magnet. The rotor part includes a sheath 4, a rotor core 12, a central permanent magnet 13 of a sinusoidal segment of the permanent magnet, a second permanent magnet 14 of the sinusoidal segment of the permanent magnet, a third permanent magnet 15 of the sinusoidal segment of the permanent magnet, and a rotating shaft 11.

[0042] The rotor core 12 is provided with four pairs of magnetic poles, and an identical stepped arc-shaped notch is opened on the outer surface corresponding to each magnetic pole of the annular rotor core 12; the middle notch of the stepped arc-shaped notch is the deepest, and the two sides are symmetrical, and the step position of the stepped arc-shaped notch gradually decreases from the two sides to the middle.

[0043] Two steps are provided on either side of the central notch of the stepped arc-shaped notch. Each stepped arc-shaped notch houses a set of matching permanent magnets. The outer peripheral end faces of the permanent magnets within all stepped arc-shaped notches form a ring. Adjacent permanent magnets and the permanent magnets to the rotor core 12 are secured together by bonding. A sheath is fitted over the outer peripheral end faces of all permanent magnets, securing them to the rotor core as a single unit. The rotor core 12 is secured to the rotating shaft 11 through its central through-hole, allowing it to rotate synchronously with the rotating shaft 11.

[0044] A group of permanent magnets arranged in a stepped arc-shaped gap includes 5 permanent magnets, that is, the permanent magnets are sinusoidally divided into 5 segments, specifically a central permanent magnet 13 of a sinusoidally segmented permanent magnet, a second permanent magnet 14 of two sinusoidally segmented permanent magnets, and a third permanent magnet 15 of two sinusoidally segmented permanent magnets.

[0045] The width of the permanent magnet is the same as the width of the stepped arc-shaped notch on the outer surface of the rotor core. The central permanent magnet 13 of the sinusoidal permanent magnet segment is placed in the middle notch. The second permanent magnets 14 of the two sinusoidal permanent magnet segments are respectively placed on both sides of the central permanent magnet 13 of the sinusoidal permanent magnet segment. The third permanent magnets 15 of the two sinusoidal permanent magnet segments are respectively placed on both sides of the second permanent magnet 14 of the sinusoidal permanent magnet segment.

[0046] The rotor core has four pairs of magnetic poles. The permanent magnet of each pole is sinusoidally divided into five segments. The width of each segment of the permanent magnet is the same. The fiber binding belt sheath is wrapped around the outside of the permanent magnet to fix it. The thickness of the third segment of the sinusoidal permanent magnet 15 is greater than 2 mm.

[0047] Example 3

[0048] This embodiment provides a high-performance, high-speed, surface-mounted permanent magnet synchronous motor with sinusoidally segmented permanent magnets. The structures of the various parts of the motor in this embodiment are the same as those in Example 1. The rotor core has four pairs of magnetic poles, and an identical stepped arc-shaped notch is opened on the outer surface corresponding to each magnetic pole of the annular rotor core. The difference is that in this embodiment, a group of permanent magnets under each magnetic pole of the rotor core includes nine permanent magnets, that is, the permanent magnets are sinusoidally divided into nine segments, and correspondingly, four steps are provided on both sides of the middle notch of the stepped arc-shaped notch of the rotor core.

[0049] Example 4

[0050] This embodiment provides a high-performance, high-speed, surface-mounted permanent magnet synchronous motor with sinusoidally segmented permanent magnets. The structures of the various parts of the motor in this embodiment are the same as those in Example 1. The rotor core has four pairs of magnetic poles, and an identical stepped arc-shaped notch is opened on the outer surface corresponding to each magnetic pole of the annular rotor core. The difference is that in this embodiment, a group of permanent magnets under each magnetic pole of the rotor core includes three permanent magnets, that is, the permanent magnets are sinusoidally divided into three segments, and correspondingly, a step is provided on each side of the middle notch of the stepped arc-shaped notch of the rotor core.

[0051] Performance tests were performed on the motors in Examples 1 to 4, and a conventional high-speed surface-mount permanent magnet synchronous motor was used as a reference.

[0052] Figure 4 and Figure 5 A schematic diagram comparing the air gap flux waveform and harmonic analysis results of a conventional high-speed surface-mount permanent magnet synchronous motor (i.e., permanent magnets of uniform thickness, represented by curve A) and the motor of the present invention is shown when the permanent magnets are sinusoidally divided into 3 segments (curve B), 5 segments (curve C), 7 segments (curve D), and 9 segments (curve E). It can be clearly seen from the figure that increasing the number of sinusoidal segments of the permanent magnets can improve the sinusoidality of the air gap flux waveform and reduce the total harmonic distortion of the air gap flux.

[0053] Figure 6 and Figure 7 A schematic diagram comparing the back-electromotive force waveforms and harmonic analysis results of a conventional high-speed surface-mount permanent magnet synchronous motor (i.e., permanent magnets of uniform thickness, represented by curve A) and the motor of the present invention is shown when the permanent magnets are sinusoidally divided into 3 segments (curve B), 5 segments (curve C), 7 segments (curve D), and 9 segments (curve E). It can be clearly seen from the figure that increasing the number of sinusoidal segments of the permanent magnets can improve the sinusoidality of the back-electromotive force waveform and reduce the total harmonic distortion of the back-electromotive force.

[0054] Figure 8 A schematic diagram comparing the cogging torque of a conventional high-speed surface-mount permanent magnet synchronous motor (i.e., permanent magnets of uniform thickness, shown as Curve A) and the motor of the present invention is shown when the permanent magnets are sinusoidally divided into 3 segments (Curve B), 5 segments (Curve C), 7 segments (Curve D), and 9 segments (Curve E). Figure 9 A schematic diagram of the peak-to-peak value of the cogging torque (curve A) under different numbers of permanent magnet segments and the torque ripple (curve B) under different numbers of permanent magnet segments is shown; it can be clearly seen from the figure that increasing the number of sinusoidal permanent magnet segments can reduce the cogging torque and torque ripple under high-speed operation.

[0055] Figure 10 and Figure 11 A schematic diagram comparing the maximum vibration acceleration and the maximum sound pressure level at 540 mm from the motor surface of a motor with unsegmented permanent magnets (i.e., permanent magnets of equal thickness, curve A) and the motor in Example 1 (curve B) at different frequencies is shown; it can be clearly seen from the figure that the present invention can significantly reduce vibration noise.

[0056] The present invention only relates to the core components of the motor. The arrangement of the stator core part and the rotating shaft and the motor housing is not within the scope of protection of the present invention. As an installation method, the stator core part is fixed to the inside of the motor base of the motor housing by an insulating "U"-shaped clip or bonding. The rotating shaft is arranged on the end covers on both sides of the motor base through bushings. The end covers are fixedly connected to the motor base. The end covers provide support for the rotating shaft without affecting its rotation.

[0057] Any matters not described in the present invention are applicable to the prior art.

Claims

1. A high-performance, high-speed, surface-mount permanent magnet synchronous motor with sinusoidal segmentation of permanent magnets, characterized in that: The motor includes a stator core, windings, a rotor core, a rotating shaft, permanent magnets, and a sheath. The stator core includes an amorphous alloy portion and a silicon steel portion. The amorphous alloy portion comprises an annular stator yoke made of laminated and bonded amorphous alloy material and N first stator teeth connected to the inner side of the annular stator yoke. The silicon steel portion comprises N second stator teeth made of laminated and bonded silicon steel. The end faces of the first stator teeth match the dimensions of the top end faces of the second stator teeth, and the two are fixed together by bonding to form N stator teeth. Windings are wound around the N stator teeth. The rotor core is located inside the stator core, and the two have the same width and are positioned opposite each other. An identical stepped arc-shaped notch is provided on the outer surface corresponding to each magnetic pole of the annular rotor core. The middle notch of the stepped arc-shaped notch has the greatest depth, and the two sides are symmetrical, with the step position of the stepped arc-shaped notch gradually decreasing from the two sides to the middle. A group of permanent magnets matching the notch are provided in each stepped arc-shaped notch, and the outer peripheral end surfaces of the permanent magnets in all stepped arc-shaped notches form a ring. Adjacent permanent magnets and the permanent magnets and the rotor core are fixed by bonding. A sheath is mounted on the outer peripheral end surfaces of all permanent magnets, so that all permanent magnets and the rotor core are fixed as a whole. The rotor core is fixed to the rotating shaft through its central through hole. Each permanent magnet in a group of permanent magnets within each stepped arc-shaped gap has the same width, the magnetization direction of each permanent magnet is perpendicular to its outer peripheral end face, and the permanent magnets in each group of permanent magnets are arranged alternately with north poles and south poles along the circumferential direction of the rotor core. The arrangement of the permanent magnets in different groups is the same; An air gap is left between the end faces of the stator teeth of the stator core and the sheath; the sheath on the peripheral end face of the permanent magnet is made of non-magnetic conductive material.

2. A high-performance, high-speed, surface-mounted permanent magnet synchronous motor with sinusoidal segmentation of permanent magnets according to claim 1, characterized in that: There are three-phase symmetrical windings wound on the N stator teeth.

3. The high-performance, high-speed surface-mounted permanent magnet synchronous motor with sinusoidal segmentation of permanent magnets according to claim 1, characterized in that: The air gap is between 0.5 mm and 0.8 mm.

4. The high-performance, high-speed, surface-mounted permanent magnet synchronous motor with sinusoidal segmentation of permanent magnets according to claim 1, characterized in that: The sheath is made of carbon fiber material.

5. The high-performance, high-speed surface-mounted permanent magnet synchronous motor with sinusoidal segmentation of permanent magnets according to claim 1, characterized in that: There are four pairs of magnetic poles on the rotor core.

6. The high-performance, high-speed, surface-mounted permanent magnet synchronous motor with sinusoidal segmentation of permanent magnets according to claim 5, characterized in that: An identical stepped arc-shaped gap is provided on the outer surface corresponding to each magnetic pole of the annular rotor core; three steps are provided on both sides of the middle gap of the stepped arc-shaped gap; a group of permanent magnets provided in a stepped arc-shaped gap includes 7 permanent magnets.

7. The high-performance, high-speed surface-mounted permanent magnet synchronous motor with sinusoidal segmentation of permanent magnets according to claim 5, characterized in that: An identical stepped arc-shaped gap is provided on the outer surface corresponding to each magnetic pole of the annular rotor core; two steps are provided on both sides of the middle gap of the stepped arc-shaped gap; a group of permanent magnets provided in a stepped arc-shaped gap includes five permanent magnets.

8. The high-performance, high-speed, surface-mounted permanent magnet synchronous motor with sinusoidal segmentation of permanent magnets according to claim 5, characterized in that: An identical stepped arc-shaped gap is provided on the outer surface corresponding to each magnetic pole of the annular rotor core; four steps are provided on both sides of the middle gap of the stepped arc-shaped gap; a group of permanent magnets provided in a stepped arc-shaped gap includes 9 permanent magnets.

9. A high-performance, high-speed, surface-mounted permanent magnet synchronous motor with sinusoidal segmentation of permanent magnets according to any one of claims 1, 6, 7, and 8, characterized in that: The thickness of each permanent magnet in a group of permanent magnets in each stepped arc-shaped gap is not less than 2 mm.

Images