Permanent magnet synchronous motor and method for manufacturing stator of permanent magnet synchronous motor

Abstract

The present disclosure relates to a permanent magnet synchronous motor, the permanent magnet comprises a rotor and a stator, the rotor comprises a first permanent magnet and a second permanent magnet, the first permanent magnet is configured as a cylinder and is integrally formed, ten spacing grooves are arranged in the first permanent magnet along the circumferential direction, and the second permanent magnet is configured as a cylinder. The first permanent magnets are arranged at intervals, the second permanent magnets are arranged in the interval grooves, the rotor is provided with ten magnetic poles which are alternately changed, the interval grooves are used for accommodating a magnetic field applying device in the orienting and magnetizing process, so that the first permanent magnets obtain permanent magnetism, and the stator is constructed as a hollow cylinder. The stator is provided with twelve groove parts in the circumferential direction, the groove parts are used for containing stator windings, tooth parts are formed between every two adjacent groove parts, tooth boots are formed at the ends of the tooth parts, and notches are formed between every two adjacent tooth boots. In addition, the invention also relates to a method for manufacturing the stator of the permanent magnet synchronous motor.

Description

Technical Field

[0001] The present disclosure relates to a permanent magnet synchronous motor and a method for manufacturing a stator of the permanent magnet synchronous motor. Background Art

[0002] A permanent magnet synchronous motor consists of a rotor and a stator. In the prior art, the rotor is usually composed of a magnetizer and a permanent magnet. The magnetizer is usually made of a stack of stamped silicon steel sheets. When non-oriented silicon steel sheets are used, the magnetization depth of the magnetizer is not deep enough. When oriented silicon steel sheets are used, the magnetization of the magnetizer will be uneven due to the specific orientation of the silicon steel sheets. In addition, the magnetizer itself is non-magnetic, which results in a waste of rotor space for the magnetizer, resulting in insufficient utilization of the rotor space and an inability to maximize the magnetic flux of the rotor. Permanent magnets can be attached to the surface of the magnetizer or embedded inside the magnetizer. In order to obtain greater magnetism and magnetic flux, permanent magnets are usually made of rare earth materials, such as neodymium iron boron. Rare earth materials are very expensive, so the cost of such a rotor is very high, and the diameter of a rotor with such a permanent magnet is not suitable for being designed too large.

[0003] To increase motor power, given a given rotor diameter and magnetic flux, the common approach is to increase the number of coils in the stator, for example by increasing the stator's cross-sectional area and slot fill ratio. This leads to higher copper and silicon steel sheet usage, resulting in higher stator costs.

[0004] In order to reduce the cost of permanent magnet synchronous motors and at the same time improve the efficiency of permanent magnet synchronous motors and make them comply with the energy efficiency levels promoted by the country, it is necessary to design a new type of permanent magnet synchronous motor. Summary of the Invention

[0005] The present disclosure provides a permanent magnet synchronous motor that has lower manufacturing costs than conventional permanent magnet synchronous motors and has very high power and energy efficiency levels. The synchronous motor according to the present disclosure can therefore be more easily and cost-effectively applied in various devices and applications.

[0006] The present disclosure provides a permanent magnet synchronous motor, wherein the permanent magnet includes a rotor and a stator, wherein the rotor includes a first permanent magnet and a second permanent magnet, the first permanent magnet is constructed as a cylinder and is integrally formed, ten spacing slots are arranged in the circumferential direction inside the first permanent magnet, the second permanent magnet is arranged in the spacing slots, and the rotor has ten alternating magnetic poles, wherein the spacing slots are used to accommodate a magnetic field application device during the orientation and magnetization process so that the first permanent magnet obtains permanent magnetism, wherein the stator is constructed as a hollow cylinder, and twelve slots are arranged in the circumferential direction of the stator, the slots are used to accommodate stator windings, a tooth portion is formed between two adjacent slot portions, a tooth shoe is formed at the end of the tooth portion, and a notch is formed between adjacent tooth shoes.

[0007] In an embodiment according to the present disclosure, the first permanent magnet is made of plastic ferrite.

[0008] In an embodiment according to the present disclosure, the second permanent magnet is made of one or more of ferrite, neodymium iron boron, samarium iron nitrogen, and samarium cobalt.

[0009] In an embodiment according to the present disclosure, a ratio of an outer diameter to an inner diameter of the stator is in a range of 1.34 to 1.53.

[0010] In an embodiment of the present disclosure, the stator is divided into a plurality of stator sub-sections along the center lines of the slots, each stator sub-section has one tooth portion, and the cross section of the stator sub-section is an arc-shaped I-section.

[0011] In an embodiment according to the present disclosure, a width of the notch is in the range of 0.6 to 2 mm.

[0012] In an embodiment according to the present disclosure, a ratio of an outer diameter arc length of the stator sub-portion to an arc length of the tooth shoe is in a range of 1.42 to 1.60.

[0013] In an embodiment according to the present disclosure, a ratio of an inter-pole arc length between adjacent poles of the rotor to an outer diameter arc length between adjacent slot portions of the stator is in a range of 0.77 to 0.90.

[0014] In an embodiment according to the present disclosure, a ratio of an arc length of a tooth shoe of the stator to an arc length between poles of adjacent poles of the rotor is in a range of 0.78 to 0.81.

[0015] In an embodiment according to the present disclosure, the groove portion is designed as a pear-shaped groove or a flat-bottomed groove.

[0016] The present disclosure also provides a method for manufacturing the stator of the motor in the above embodiment, wherein the stator is divided into a plurality of stator sub-sections along the center lines of each of the slot portions, each stator sub-section has a tooth portion, and the cross-section of the stator sub-section is an I-shape with a curvature; the method comprises: arranging the stator sub-sections in a straight line; arranging stator conductors between the stator sub-sections; and connecting the stator sub-sections into the stator.

[0017] In the prior art, the permanent magnets in the rotor are usually made of rare earth materials with high magnetic energy product, such as neodymium iron boron. Rare earth materials are national strategic resources and have a very high price, which results in a high cost for permanent magnets made of rare earth materials. In addition, when the size or volume of the permanent magnet made of rare earth is large, the permanent magnet cannot be magnetized very deeply, resulting in its magnetism being concentrated on the surface of the permanent magnet. For the above two reasons, traditional rotors are not designed to be too large. In the case of permanent magnets made of rare earth, an oversized rotor is expensive on the one hand and wastes expensive rare earth materials on the other hand. According to the first permanent magnet in the rotor of the motor of the present disclosure, it can provide a magnetic field and magnetic flux, so the second permanent magnet can be manufactured using less rare earth material, or the second permanent magnet can also be made of sintered ferrite. In either case, the rotor of the motor according to the present disclosure has a lower cost.

[0018] The permanent magnet synchronous motor according to the present disclosure has a larger rotor diameter than conventional permanent magnet synchronous motors. Given a given overall motor diameter, the permanent magnet synchronous motor according to the present disclosure has a thinner stator. Therefore, the size of the rotor and stator of the permanent magnet synchronous motor according to the present disclosure differs significantly from that of conventional permanent magnet synchronous motors. Because the rotor of the permanent magnet synchronous motor according to the present disclosure has a larger diameter, the overlap area between the rotor and stator is larger, which improves the motor's power density and torque. The thinner stator of the permanent magnet synchronous motor according to the present disclosure reduces the amount of silicon steel sheets used and the amount of wire, i.e., copper, used in the stator, further reducing the motor's manufacturing cost. The smaller difference between the stator's inner and outer diameters shortens the magnetic circuit in the stator and reduces magnetic losses, thereby improving the motor's power and efficiency. Furthermore, the stator of the permanent magnet synchronous motor according to the present disclosure has a narrower slot, which reduces the gap between the tooth shoes and increases the overlap area between the rotor and stator, thereby improving the motor's power density and torque. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] To more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some exemplary embodiments of the present disclosure, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0020] Figure 1 shows a schematic cross-sectional view of a permanent magnet synchronous motor according to an embodiment of the present disclosure,

[0021] Figure 2 FIG1 shows an exploded perspective view of a rotor of a permanent magnet synchronous motor according to an embodiment of the present disclosure.

[0022] Figure 3 shows a schematic cross-sectional view of a stator of a permanent magnet synchronous motor according to an embodiment of the present disclosure,

[0023] Figure 4 shows a schematic cross-sectional view of a rotor of a permanent magnet synchronous motor according to an embodiment of the present disclosure,

[0024] Figure 5 A schematic diagram of a magnetic circuit of a rotor of a permanent magnet synchronous motor according to an embodiment of the present disclosure is shown.

[0025] Figure 6 shows a partial schematic diagram of the magnetic circuit of the permanent magnet synchronous motor according to an embodiment of the present disclosure,

[0026] Figure 7 shows a schematic diagram of stator subsections arranged in a straight line according to an embodiment of the present disclosure,

[0027] Figure 8 A schematic diagram showing a linear arrangement of stator subsections after stator conductors are arranged according to an embodiment of the present disclosure, and

[0028] Figure 9 A schematic diagram of a stator formed by joining stator subsections according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the technical solution of the present disclosure clearer, the technical solution of the embodiment of the present disclosure will be clearly and completely described below in conjunction with the drawings of the specific embodiments of the present disclosure. The same figure marks in the drawings represent the same parts. It should be noted that the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0030] Compared to the embodiments shown in the drawings, feasible embodiments within the scope of protection of the present disclosure may have fewer components, additional components not shown in the drawings, different components, differently arranged components, or differently connected components, etc. In addition, two or more components in the drawings may be implemented in a single component, or a single component shown in the drawings may be implemented as multiple separate components.

[0031] Figure 1 A schematic cross-sectional view of a permanent magnet synchronous motor 100 according to an embodiment of the present disclosure is shown. The permanent magnet synchronous motor 100 includes a rotor 110 and a stator 120. The rotor 110 has five pairs of magnetic poles (ten poles) and provides a constant magnetic field. Stator windings are arranged in the slots of the stator 120, and twelve slots are provided in the present disclosure. Three-phase alternating current or more-phase alternating current is applied to the stator winding to generate a rotating magnetic field. The rotating magnetic field of the stator interacts with the magnetic field of the rotor and generates torque on the rotor and causes the rotor to rotate at a synchronous speed.

[0032] When the motor size or stator diameter is constant, in order to improve the power and torque of the motor, the number of rotor poles and the number of stator slots can be increased. However, the number of rotor poles and the number of stator slots cannot be increased indefinitely. The optimal motor power and torque correspond to a specific number of rotor poles, the number of stator slots, and the ratio of the number of stator slots to the number of rotor poles. For example, when the number of rotor poles is too large or the ratio of the number of stator slots to the number of rotor poles is too small, the surface area of each rotor pole is too small and will negatively affect the back electromotive force and the motor torque. When the number of stator slots is too large, the space of each stator slot will be too small and the number of coil turns will be reduced. This will also negatively affect the back electromotive force and the motor torque. According to the experience of the inventors of the present disclosure, when the stator diameter is less than or equal to 175 mm, the permanent magnet synchronous motor 100 adopts a ten-pole twelve-slot design to achieve optimal performance.

[0033] The rotor 110 includes a first permanent magnet 111 and a second permanent magnet 112 . Figure 2 FIG. 1 shows an exploded perspective view of the rotor 110 of the permanent magnet synchronous motor according to an embodiment of the present disclosure. Figure 2The shape, structure, and assembly relationship of the first permanent magnet 111 and the second permanent magnet 112 can be more clearly seen in the figure. The first permanent magnet 111 is constructed as a cylinder and is integrally formed. In the present disclosure, the first permanent magnet 111 is constructed as a cylinder, in particular, it is understood that the outer contour of the first permanent magnet 111 is a cylinder. In the present disclosure, the first permanent magnet 111 is constructed as a cylinder, in particular, it is understood that the outer contour of the first permanent magnet 111 is a cylinder. In an embodiment according to the present disclosure, the outer circumferential surface of the first permanent magnet 111 can be, for example, a closed surface to achieve better structural strength. Ten spacing grooves 113 are arranged circumferentially inside the first permanent magnet 111, and the first permanent magnet 111 is divided into ten first permanent magnet sub-sections by the spacing grooves. In an embodiment according to the present disclosure, the spacing grooves 113 pass through the first permanent magnet 111 in the longitudinal direction, that is, in the axial direction of the first permanent magnet 111. The second permanent magnets 112 are respectively arranged in the ten spacing slots 113, and in particular are inserted into the spacing slots 113. The rotor 110 has ten alternating magnetic poles, that is, alternating N poles and S poles, as shown in FIG. Figure 1 The spacing groove 113 is configured to accommodate a magnetic field applying device during the orientation process so that the first permanent magnet 111 obtains a deeper orientation, and is also configured to accommodate another magnetic field applying device during the magnetization process so that the first permanent magnet 111 obtains a stronger permanent magnetism.

[0034] In an embodiment of the present disclosure, the first permanent magnet 111 of the rotor 110 can be made of a material with a low magnetic energy product, such as plastic ferrite. Plastic ferrite is a mixture of ferrite and nylon. During the injection molding process of the plastic ferrite into the first permanent magnet 111, a magnetic field application device, i.e., a strong magnetic orientation device, is placed in the spacing slots 113 of the first permanent magnet 111 to orient the first permanent magnet 111. After orientation, the small magnetic poles in the first permanent magnet 111 are aligned in the desired magnetic field direction. This results in a stronger magnetism for the magnetized first permanent magnet 111. During the magnetization process, a magnetic field application device, i.e., a strong magnetic magnetization device, is placed in the spacing slots 113 of the first permanent magnet 111 to magnetize the first permanent magnet 111, thereby imparting permanent magnetism to the first permanent magnet 111. The provision of the spacing slots 113 allows the first permanent magnet 111 to achieve a deep magnetization depth and magnetization depth. Furthermore, plastic ferrite has a lower density than silicon steel, which reduces the weight of rotors made from it, thereby improving the power and energy efficiency of motors. Furthermore, plastic ferrite has a higher resistivity than silicon steel, so rotors made from plastic ferrite can effectively reduce eddy current losses compared to rotors made from silicon steel.

[0035] The stator 120 is constructed as a hollow cylinder. This is particularly understood to mean that the outer contour of the stator 120 is a hollow cylinder. In the present disclosure, the stator 120 is constructed as a hollow cylinder, in particular, it is understood that the outer contour of the stator 120 is a hollow cylinder. The stator 120 is arranged with twelve slots 121 in the circumferential direction. The slots 121 respectively have radially inward slots 1211. The slots 121 are used to accommodate stator windings, and the stator windings are used to generate a rotating magnetic field. In an embodiment according to the present disclosure, a tooth portion 122 is formed between two adjacent slot portions 121, and a tooth shoe 1221 is formed at the end of the tooth portion 122. A slot 1211 is respectively formed between adjacent tooth shoes 1221. In an embodiment according to the present disclosure, the slot portion 121 can be designed as a pear-shaped slot or a flat-bottomed slot, for example.

[0036] In the prior art, the traditional permanent magnet rotor in a permanent magnet synchronous motor consists of a permanent magnet and a magnetizer. The permanent magnet is made of rare earth material, and the magnetizer is made of stacked silicon steel sheets. The permanent magnet can be attached to the surface of the magnetizer to form a surface-mounted rotor, or the permanent magnet can be inserted into the magnetizer to form an embedded rotor. The disadvantage of this rotor is that the magnetizer itself takes up space in the rotor but does not provide magnetic flux; it only serves to guide the magnet. In addition, the process of stamping silicon steel sheets is complex and the cost of silicon steel sheets is high. Compared to the prior art, the rotor of the motor according to the present disclosure uses a first permanent magnet instead of a magnetizer. The first permanent magnet can itself provide magnetic force, and its magnetic permeability is much higher than that of the silicon steel sheet magnetizer. Therefore, the rotor of the motor according to the present disclosure has a higher power density. In addition, the first permanent magnet according to the present disclosure can be injection molded from a plastic magnetic material and can therefore be easily produced through an integrated molding process. Compared to the process of stamping and stacking silicon steel sheets, the integrated molding process of the first permanent magnet is simple, efficient, precise, and low-cost.

[0037] In the prior art, the permanent magnets in the rotor are usually made of rare earth materials with high magnetic energy product, such as neodymium iron boron. Rare earth materials are national strategic resources and have a very high price, which results in a high cost for permanent magnets made of rare earth materials. In addition, when the size or volume of the permanent magnet made of rare earth is large, the permanent magnet cannot be magnetized very deeply, resulting in its magnetism being concentrated on the surface of the permanent magnet. For the above two reasons, traditional rotors are not designed to be too large. In the case of permanent magnets made of rare earth, an oversized rotor is expensive on the one hand and wastes expensive rare earth materials on the other hand. According to the first permanent magnet in the rotor of the motor of the present disclosure, it can provide a magnetic field and magnetic flux, so the second permanent magnet can be manufactured using less rare earth material, or the second permanent magnet can also be made of sintered ferrite. In either case, the rotor of the motor according to the present disclosure has a lower cost.

[0038] In general, the rotor of the permanent magnet synchronous motor according to the present disclosure is mainly made of ferrite, without using silicon steel sheets, using only a small amount of rare earth materials or not using any rare earth materials at all. The rotor of the motor according to the present disclosure can also provide the same magnetic flux as a traditional permanent magnet rotor.

[0039] Plastic ferrite is a material with low magnetic energy product. When the rotor according to the present invention provides the same magnetic flux as a traditional permanent magnet rotor, the rotor of the motor according to the present invention has a larger diameter. In practical applications, permanent magnet synchronous motors usually have standard sizes to facilitate application in different devices and scenarios. This standard size is reflected in a specific radius size or a specific shaft center height of the permanent magnet synchronous motor as a whole. Therefore, when the radius of the motor as a whole is constant and the radius of the rotor is larger, the outer diameter of the stator remains unchanged and the inner diameter of the stator becomes larger. In other words, the stator of the permanent magnet synchronous motor according to the present invention becomes thinner. Figure 3 FIG1 shows a schematic cross-sectional view of the stator 120 of the permanent magnet synchronous motor 100 according to an embodiment of the present disclosure. Figure 3 , specifically shows the outer diameter D of the stator 120 and the inner diameter d of the stator 120. In an embodiment according to the present disclosure, the ratio of the outer diameter to the inner diameter of the stator 120 (D / d) is in the range of 1.34 to 1.53. This ratio varies within the above range as the motor size, such as the stator diameter, changes. Compared with the stator of the synchronous motor according to the present disclosure, the stator of a conventional permanent magnet synchronous motor, i.e., a permanent magnet synchronous motor in which the permanent magnets in the rotor are made of rare earth materials, has a thicker size, and its outer diameter to inner diameter ratio (D / d) is in the range of 2.10 to 2.25. Based on the thinner stator design, the stator of the permanent magnet synchronous motor according to the present disclosure uses less silicon steel sheets, and the amount of stator coils is reduced, i.e., the amount of copper used is reduced. This further reduces the cost of manufacturing the permanent magnet synchronous motor according to the present disclosure.

[0040] In the embodiment of the present disclosure, the stator 120 can be divided into a plurality of stator sub-sections 310 along the center line of each slot portion 121. Each stator sub-section 310 has one tooth portion 122. The cross section of the stator sub-section 310 is an arc-shaped "I" shape. Figure 3. In other words, the cross-section of the stator 120 is annular, and the stator 120 is divided into a plurality of sector ring segments along the center lines of each slot portion 121. In this embodiment, the stator 120 is divided into twelve sector ring segments, i.e., twelve stator sub-sections 310. Since there is a tooth portion 122 and a tooth shoe 1221 in each sector ring segment, the cross-section of the sector ring segment is an arc-shaped "I". The ratio of the outer diameter arc length to the inner diameter arc length of the stator sub-section 310 or the sector ring segment is equal to the ratio of the outer diameter to the inner diameter of the stator 120. In the embodiment of the present disclosure, the ratio of the outer diameter arc length to the inner diameter arc length of the stator sub-section 310 is in the range of 1.34 to 1.53.

[0041] Slots 1211 are formed between adjacent tooth shoes 1221. In embodiments of the present disclosure, the width H of slots 1211 can be, for example, in the range of 0.6 to 2 mm. The width H of slots 1211 increases, for example, as the stator outer diameter increases. Compared to slots in conventional permanent magnet synchronous motor stators in the prior art, the slot width in embodiments of the present disclosure is significantly smaller, even smaller than the diameter or side length of the stator conductor arranged in the slot.

[0042] In an embodiment of the present disclosure, based on a very small slot width, the ratio of the outer diameter arc length L of the stator subsection 310 to the tooth shoe arc length k (L / k) can be, for example, in the range of 1.42 to 1.60. This ratio varies within the above range as the motor size, such as the stator diameter, changes. Compared to the stator of the synchronous motor according to the present disclosure, the stator of a conventional permanent magnet synchronous motor, i.e., a permanent magnet synchronous motor in which the permanent magnets in the rotor are made of rare earth materials, has a thicker stator and a larger slot width. Therefore, the ratio of the outer diameter arc length of the stator subsection to the tooth shoe arc length (L / k) thereof is in the range of 2.50 to 3.30.

[0043] This very small slot width reduces the gap between adjacent tooth shoes. This reduces stator magnetic flux leakage, thereby reducing motor losses and improving motor power and efficiency. This very small slot width also increases the overlap area between the arcuate surface of the stator tooth shoe and the circumferential surface of the rotor, thereby increasing the motor's power density and torque.

[0044] The large overlap area between the arc surface of the tooth shoe of the stator tooth portion and the circumferential surface of the rotor can be reflected, for example, by the ratio of the arc length between adjacent poles of the rotor to the arc length of the outer diameter of the stator portion, or by the ratio of the arc length between adjacent poles of the rotor to the arc length of the tooth shoe. Figure 4FIG. 1 is a schematic cross-sectional view of a rotor 110 of a permanent magnet synchronous motor 100 according to an embodiment of the present disclosure. The interpole arc length J between adjacent poles of the rotor 110 can be, for example, the arc length from the S pole to the adjacent N pole on the outer circumference of the rotor, or the outer diameter arc length between the second permanent magnets 112, where the arc lengths are equal.

[0045] In an embodiment according to the present disclosure, the ratio (J / L) of the interpole arc length J between adjacent poles of the rotor 110 to the outer diameter arc length L between adjacent slots 121 of the stator 120 (i.e., the outer diameter arc length L of the stator subsection 310) can be, for example, in the range of 0.77 to 0.90. This ratio varies within the aforementioned range as the motor size, such as the stator diameter, changes. Compared to the stator of the synchronous motor according to the present disclosure, the stator of a conventional permanent magnet synchronous motor, i.e., a permanent magnet synchronous motor in which the permanent magnets in the rotor are made of rare earth materials, has a thicker stator and a larger slot width. Therefore, the ratio (J / L) of the interpole arc length J between adjacent poles of the rotor to the outer diameter arc length L between adjacent slots 121 of the stator 120 is in the range of 0.52 to 0.55.

[0046] In an embodiment according to the present disclosure, the ratio (k / J) of the arc length k of the tooth shoe of the stator 120 to the arc length J between the poles of the adjacent poles of the rotor 110 can be, for example, in the range of 0.78 to 0.81. This ratio varies within the above range as the motor size, such as the stator diameter, changes. Compared with the stator of the synchronous motor according to the present disclosure, the stator of a conventional permanent magnet synchronous motor, i.e., a permanent magnet synchronous motor in which the permanent magnets in the rotor are made of rare earth materials, has a thicker size and a larger slot width. Therefore, the ratio (k / J) of the arc length k of the tooth shoe of the stator to the arc length J between the poles of the adjacent poles of the rotor is in the range of 0.56 to 0.73.

[0047] The permanent magnet synchronous motor according to the present disclosure has a larger rotor diameter than conventional permanent magnet synchronous motors. Given a given overall motor diameter, the permanent magnet synchronous motor according to the present disclosure has a thinner stator. Therefore, the size of the rotor and stator of the permanent magnet synchronous motor according to the present disclosure differs significantly from that of conventional permanent magnet synchronous motors. Because the rotor of the permanent magnet synchronous motor according to the present disclosure has a larger diameter, the overlap area between the rotor and stator is larger, which improves the motor's power density and torque. The thinner stator of the permanent magnet synchronous motor according to the present disclosure reduces the amount of silicon steel sheets used and the amount of wire, i.e., copper, used in the stator, further reducing the motor's manufacturing cost. The smaller difference between the stator's inner and outer diameters shortens the magnetic circuit in the stator and reduces magnetic losses, thereby improving the motor's power and efficiency. Furthermore, the stator of the permanent magnet synchronous motor according to the present disclosure has a narrower slot, which reduces the gap between the tooth shoes and increases the overlap area between the rotor and stator, thereby improving the motor's power density and torque.

[0048] In general, the permanent magnet synchronous motor disclosed herein reduces the use of rare earth elements, copper, and silicon steel sheets, while also offering lower manufacturing costs. However, due to its structure, the synchronous motor disclosed herein can achieve very high power and energy efficiency levels. Therefore, the synchronous motor disclosed herein can be more easily and cost-effectively applied in a variety of equipment and applications.

[0049] Figure 5 A schematic diagram of the magnetic circuit of the rotor 110 of the permanent magnet synchronous motor 100 according to an embodiment of the present disclosure is shown. The rotor 110 has alternating N poles and S poles and forms a rotor with a pole pair number of 5 (10 poles). Inside the rotor 110, the first permanent magnet sub-portion corresponding to the S pole has a magnetic field direction extending radially inward, and the first permanent magnet sub-portion corresponding to the N pole has a magnetic field direction extending radially outward. Between adjacent S poles and N poles, the magnetic field starts from the S pole, transitions through the second permanent magnet in the shortest path and reaches the N pole, and the magnetic field in the second permanent magnet extends in the circumferential direction. Figure 5 1 . The second permanent magnets 511, 512, and 513 are shown in FIG. The magnetic field direction of the second permanent magnet 513 extends along the circumferential direction of the rotor 110 and is opposite to the magnetic field direction of the adjacent second permanent magnet 512. On both sides of the second permanent magnet 512 are the first permanent magnet sub-sections 521 and 522, and on both sides of the second permanent magnet 513 are the first permanent magnet sub-sections 522 and 523. Figure 5As can be seen in the figure, the magnetic field originates from the south pole corresponding to the first permanent magnet sub-section 522 and extends inward in the radial direction of the first permanent magnet 111 within the first permanent magnet sub-section 522. The magnetic field then splits, with one portion bending through the second permanent magnet 512 and the other portion bending through the second permanent magnet 513. The magnetic field extends counterclockwise along the circumferential direction of the rotor 110 within the second permanent magnet 512. After passing through the second permanent magnet 512, the magnetic field bends and extends outward in the radial direction of the first permanent magnet 111 through the first permanent magnet sub-section 521, reaching the north pole corresponding to the first permanent magnet sub-section 521. The magnetic field extends clockwise along the circumferential direction of the rotor 110 within the second permanent magnet 513. After passing through the second permanent magnet 513, the magnetic field bends and extends outward in the radial direction of the first permanent magnet 111 through the first permanent magnet sub-section 523, reaching the north pole corresponding to the first permanent magnet sub-section 523. Based on the above description of the directions and orientations of the magnetic fields in the first permanent magnet sub-portions 521 , 522 and 523 and the second permanent magnets 512 and 513 , the directions and orientations of the magnetic fields in the other first permanent magnet sub-portions and second permanent magnets can be understood by comparison.

[0050] Figure 6 FIG. 1 is a partial schematic diagram of a magnetic circuit of a permanent magnet synchronous motor 100 according to an embodiment of the present disclosure. Figure 6Figure 2 shows the closed magnetic circuit formed by the magnetic field in the rotor 110 and stator 120. For example, the magnetic field originates from the first permanent magnet subsection 521 of the rotor 110 and extends radially outward within the first permanent magnet subsection 521. This magnetic field passes through the air gap and slot gap between the rotor 110 and stator 120 and reaches the tooth shoe of the stator 120. Specifically, the majority of the magnetic field passes through the air gap and reaches the tooth shoe 6121, while a smaller portion passes through the air gap and reaches the tooth shoe 6221, passing through the slot 6121 and also reaching the tooth shoe 6211. The magnetic field then extends radially outward within the corresponding tooth 621 and reaches the stator yoke 620. The stator yoke 620 is formed at the outermost periphery of the stator 120 and is a hollow cylinder. The stator yoke 620 is used to guide the magnetic field or magnetic flux through and form a closed magnetic circuit. After reaching the stator yoke 620, a portion of the magnetic field bends and extends clockwise to reach the tooth 622. This portion of the magnetic field extends radially inward within the tooth 622, reaching the tooth shoe 6221, and then passes through the air gap and the slot 6131 of the slot 613 to reach the first permanent magnet sub-segment 522 of the rotor 110. In other words, this portion of the magnetic field extends clockwise around the slot 612. Another portion of the magnetic field bends and extends counterclockwise to the tooth 623. This portion of the magnetic field extends radially inward within the tooth 623, reaching the tooth shoe 6231, and then passes through the air gap to reach the first permanent magnet sub-segment 524 of the rotor 110. In other words, this other portion of the magnetic field extends counterclockwise around the slot 611. The magnetic field direction and magnetic path extension of the stator 120 around the other slots can be compared with the magnetic field direction and magnetic path extension of the stator 120 around the slots 612 and 611. The magnetic path of the stator 120, together with the magnetic path of the rotor 110, forms a closed magnetic path. The rotating magnetic field of the stator 120 interacts with the magnetic field of the rotor 110 and generates torque on the rotor 110 and causes the rotor 110 to rotate at a synchronous speed.

[0051] Compared to conventional slots in conventional permanent magnet synchronous motors, the slot width of the stator slots in the permanent magnet synchronous motor according to the present disclosure is significantly smaller, even smaller than the diameter or side length of the stator conductors arranged in the slots. To arrange the stator coils or stator conductors in the slots, a new method for manufacturing the motor stator is required. This method includes: arranging the stator subsections in a straight line; arranging the stator conductors between the stator subsections; and joining the stator subsections to form the stator. Figure 7 、 Figure 8 and Figure 9 Together, a method for producing a stator for an electric machine is shown.

[0052] Figure 7 FIG. 7 is a schematic diagram of a linearly arranged stator subsection 710 according to an embodiment of the present disclosure. The linearly arranged stator subsection 710 constitutes a straight bar stator 700 . Figure 7 The twelve stator subsections 710 shown in FIG can be wound into a circle and welded to form a hollow cylindrical stator with twelve slots. When the stator subsections 710 are arranged in a straight line, the width of the slots 721 is very large and it is very easy to arrange the stator conductors in the slots 720. Figure 8 FIG. 1 shows a schematic diagram of a linearly arranged stator subsection 710 after arranging the stator conductors 730 according to an embodiment of the present disclosure. Figure 8 As shown in FIG, the stator conductor 730 can be arranged in the slot portion 720 through the notch 721. After the stator conductor 730 is arranged in the slot portion 720, the individual stator subsections 710 are circled and joined, for example, welded, to form a hollow cylindrical stator. Figure 9 FIG. 1 shows a schematic diagram of a stator 900 formed by joining stator subsections according to an embodiment of the present disclosure. Figure 9 As can be seen in the figure, the resulting stator 900 has a very small slot width H. This slot width H is significantly smaller than the width or diameter of the stator conductor. This very small slot width reduces the gap between adjacent tooth shoes. This reduces stator magnetic flux leakage, thereby reducing motor losses and improving motor power and efficiency. This very small slot width also increases the overlap area between the arcuate surfaces of the stator tooth shoes and the circumferential surface of the rotor, thereby increasing the motor's power density and torque. In embodiments according to the present disclosure, the slot width H can, for example, be in the range of 0.6 to 2 mm, and the slot width H increases, for example, with increasing stator outer diameter. For example, when the stator outer diameter is 78 mm, the slot width is preferably 0.6 mm; when the stator outer diameter is 90 mm, the slot width is preferably 1.2 mm; when the stator outer diameter is 110 mm, the slot width is preferably 1.5 mm; and when the stator outer diameter is 175 mm, the slot width is preferably 2 mm. Under these preferred conditions, the motor stator can meet the mold strength requirements during stator punching, and the motor with such a stator can achieve the best efficiency, the lowest noise, and the highest torque.

[0053] In this document, unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by persons of ordinary skill in the field to which the present disclosure belongs. The words "first", "second" and similar terms used in the patent application specification and claims of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "a" do not necessarily indicate a quantity limitation. Words such as "include" or "comprising" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0054] The exemplary implementation schemes proposed in the present disclosure are described in detail above with reference to preferred embodiments. However, it will be understood by those skilled in the art that, without departing from the concept of the present disclosure, various modifications and variations can be made to the above-mentioned specific embodiments, and various technical features and structures proposed in the present disclosure can be combined in various ways without exceeding the scope of protection of the present disclosure, which is determined by the appended claims.

Claims

1. A permanent magnet synchronous motor comprising a rotor and a stator, in, The rotor includes a first permanent magnet and a second permanent magnet. The first permanent magnet is configured as a cylinder and is integrally formed. Ten spacing slots are arranged in the circumferential direction inside the first permanent magnet. The second permanent magnet is arranged in the spacing slots. The rotor has ten alternating magnetic poles. The spacing groove is used to accommodate a magnetic field applying device during the orientation and magnetization process, so that the first permanent magnet obtains permanent magnetism. The stator is constructed as a hollow cylinder, and twelve slots are arranged in the circumferential direction. The slots are used to accommodate stator windings, a tooth portion is formed between two adjacent slots, a tooth shoe is formed at the end of the tooth portion, and a slot is formed between adjacent tooth shoes.

2. The motor according to claim 1, wherein The first permanent magnet is made of plastic ferrite.

3. The motor according to claim 1, wherein The second permanent magnet is made of one or more of ferrite, neodymium iron boron, samarium iron nitrogen and samarium cobalt.

4. The motor according to claim 1, wherein A ratio of an outer diameter to an inner diameter of the stator is in a range of 1.34 to 1.

53.

5. The motor according to claim 1, wherein The stator is divided into a plurality of stator sub-sections along the center lines of the slots. Each stator sub-section has one tooth portion. The cross section of the stator sub-section is an I-shape with a curvature.

6. The motor according to claim 1, wherein The width of the notch is in the range of 0.6 to 2 mm.

7. The motor according to claim 5, wherein A ratio of an outer diameter arc length of the stator subsection to an arc length of the tooth shoe is in a range of 1.42 to 1.

60.

8. The motor according to claim 1, wherein A ratio of an inter-pole arc length between adjacent poles of the rotor to an outer diameter arc length between adjacent slot portions of the stator is in a range of 0.77 to 0.

90.

9. The motor according to claim 1, wherein A ratio of an arc length of a tooth shoe of the stator to an arc length between adjacent poles of the rotor is in a range of 0.78 to 0.

81.

10. The motor according to claim 1, wherein The groove portion is designed as a pear-shaped groove or a flat-bottomed groove.

11. A method for producing a stator for an electric machine according to any one of the preceding claims, wherein: The stator is divided into a plurality of stator sub-sections along the center lines of the slots, each stator sub-section has one tooth portion, and the cross section of the stator sub-section is an I-shape with a curvature; The method comprises: arranging the stator subsections in a straight line; arranging stator conductors between the stator subsections; and The stator subsections are joined to form the stator.

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