A high magnetic flux asymmetric magnetic barrier motor rotor structure

Abstract

The invention discloses a high-flux asymmetric magnetic barrier motor rotor structure, including a rotor body and a plurality of permanent magnet groups arranged on the rotor body; each permanent magnet group includes n layers of permanent magnet units from the inside to the outside in the radial direction, and each layer of permanent magnet units includes a middle section permanent magnet and side permanent magnets on both sides; the side permanent magnets are installed in the air slots on both sides of the middle section permanent magnets, and the air slot areas outside the side permanent magnets constitute air slot magnetic barriers; between two adjacent layers of permanent magnet units, the outside of the outermost layer of permanent magnet units, and the inside of the innermost layer of permanent magnet units are rotor magnetic grids; each air slot magnetic barrier is tapered with a thickness gradually decreasing from the inside to the outside; the rotor magnetic grid portion corresponding to the two adjacent layers of air slot magnetic barriers gradually widens from the inside to the outside. The invention can significantly reduce the difficulty of motor control and improve the stability of motor operation under the premise of improving the torque density of the motor, reducing torque pulsation, and improving the anti-demagnetization ability of the permanent magnet.

Description

Technical Field

[0001] The invention relates to the technical field of motor equipment, and in particular to a high magnetic flux asymmetric magnetic barrier motor rotor structure. Background Art

[0002] At present, the new energy electric drive industry mainly uses rare earth permanent magnet motors as drive motors, which have higher power density than other types of motors, that is, they can achieve the same output power in a smaller volume. However, in recent years, due to the large fluctuations in the cost of rare earth permanent magnets, permanent magnet-assisted synchronous reluctance motors that use cheaper ferrite permanent magnets instead of rare earth permanent magnets have become a popular research and development direction.

[0003] For example, Chinese patent document CN102769367A discloses a permanent magnet assisted synchronous reluctance motor, which is provided with multiple layers of permanent magnet slots and multiple layers of magnets. This makes the motor fully utilize the permanent magnet flux linkage, and the motor's ability to generate reluctance torque is also greatly improved, thereby achieving the purpose of improving the efficiency of the motor using ferrite permanent magnets.

[0004] A Chinese patent document with publication number CN215646411U discloses a permanent magnet assisted synchronous reluctance motor rotor, comprising: a rotor core, a plurality of magnetic barrier groups are arranged circumferentially of the rotor core, the magnetic barrier groups include at least 4 layers of magnetic barriers arranged in sequence along the radial direction of the rotor core, wherein, in the same magnetic barrier group, among the magnetic barriers from inside to outside along the radial direction of the rotor core, except for the outermost magnetic barrier, the innermost magnetic barrier and the magnetic barrier close to the outermost magnetic barrier are both provided with neodymium iron boron permanent magnets, and the remaining layers of magnetic barriers are all provided with ferrite permanent magnets.

[0005] Since ferrite has lower residual magnetism than rare earth permanent magnets, the torque density of permanent magnet assisted synchronous reluctance motor is usually lower than that of rare earth permanent magnets, which means that to achieve the same torque, the motor needs to be larger and heavier. If the design is unreasonable, the power density advantage of the permanent magnet motor itself will be lost. Therefore, improving the torque output of the motor under a certain volume is the most important issue in motor design. The torque composition of the permanent magnet assisted synchronous reluctance motor includes permanent magnet torque and reluctance torque. Therefore, it is necessary to design the rotor topology structure and reasonably arrange the magnetic circuit direction to maximize the combination of the two torque outputs to give full play to the output capacity of the motor.

[0006] In addition, there are usually two key points to pay attention to when using permanent magnet assisted synchronous reluctance motors with ferrite. The first is that the torque pulsation of this type of motor may be large, which will cause the motor to have large vibration noise, and the torque pulsation needs to be reduced through reasonable rotor topology design. Another key point is that the intrinsic coercive force of ferrite permanent magnets is lower than that of rare earth permanent magnets, which makes ferrites more susceptible to demagnetization, and the magnetic properties of permanent magnets are reduced, resulting in a decrease in the output performance of the motor.

[0007] The motor rotor structure designed by the applicant before highlights the reluctance torque of the motor, and the permanent magnet flux of the motor is low, and the back electromotive force is relatively low. However, the control difficulty of the motor with high reluctance torque is high, and the motor with high reluctance torque requires more copper wire windings, which is more expensive. Therefore, in order to reduce the control difficulty and cost, the existing motor rotor structure needs to be improved. Summary of the invention

[0008] The present invention provides a high-flux asymmetric magnetic barrier motor rotor structure, which can significantly reduce the difficulty of motor control, improve the stability of motor operation, and reduce manufacturing costs while improving the torque density of the motor, reducing torque pulsation, and improving the anti-demagnetization ability of permanent magnets.

[0009] A high magnetic flux asymmetric magnetic barrier motor rotor structure, comprising a rotor body and a plurality of permanent magnet groups uniformly arranged on the rotor body in a circumferential direction;

[0010] Each permanent magnet group includes n layers of permanent magnet units from the inside to the outside in the radial direction, and each layer of permanent magnet units includes a middle section permanent magnet of a rectangular structure and symmetrical side permanent magnets on both sides; the side permanent magnets are installed in air slots arranged on both sides of the middle section permanent magnet, and the air slot area outside the side permanent magnets constitutes an air slot magnetic barrier;

[0011] The rotor magnetic grids are located between two adjacent layers of permanent magnet units, on the outside of the outermost layer of permanent magnet units, and on the inside of the innermost layer of permanent magnet units; each air slot magnetic barrier is conical in shape with thickness gradually decreasing from the inside to the outside, and the air magnetic barriers on both sides corresponding to each layer of permanent magnet units are asymmetric; the rotor magnetic grid portion corresponding to the space between two adjacent layers of air slot magnetic barriers gradually widens from the inside to the outside.

[0012] The present invention reasonably arranges the position and structure of the air slot magnetic barrier in the design to reduce the torque pulsation of the motor and reduce the vibration noise when the motor is running. The design can improve the working point of the permanent magnet and enhance the anti-demagnetization ability of the permanent magnet to increase the reliability of the motor. At the same time, the middle section permanent magnet and the side permanent magnets on both sides are designed to cooperate with the corresponding air slot magnetic barriers, and as many permanent magnets as possible are used to enhance the permanent magnet torque of the motor, thereby increasing the torque density of the motor.

[0013] In the present invention, the middle section permanent magnet and the side permanent magnet can be made of ferrite permanent magnet or other types of permanent magnet.

[0014] In the present invention, the width ratio of the air slot magnetic barrier and the side permanent magnet can be adjusted. Specifically, in each layer of permanent magnet units, the width of the side permanent magnet is recorded as MWS, the sum of the widths of the side permanent magnet and the air slot magnetic barrier is recorded as LWS, and the ratio of MWS to LWS is recorded as the coefficient Kw. Except for the outermost layer of permanent magnet units, other layers must satisfy 0.3≤Kw≤0.9, and the coefficient Kw of the inner layer of permanent magnet units is greater than that of the outer layer. The arrangement of the side permanent magnets can effectively improve the permanent magnet flux linkage of the motor and enhance the permanent magnet torque output. The width ratio Kw can be adjusted, which can provide optimization space for a more reasonable magnetic circuit arrangement and find the optimal solution for motor output performance in different topologies.

[0015] Preferably, an arc segment parallel to the outer circle of the rotor body is provided outside the conical segment of the air slot magnetic barrier, and a rounded corner transition is provided between the conical segment and the arc segment. This arrangement can reduce the sudden change of air gap magnetic density at the outer circle, so as to optimize the design of torque pulsation.

[0016] The position of the air slot magnetic barrier on the outer circle of the rotor is adjustable. Preferably, in each layer of permanent magnet units, the thickness of the side permanent magnets is recorded as MTS, and the distances between the two side extension lines of the two side permanent magnets close to the symmetry center line and the outer arc center line of the corresponding air slot magnetic barrier are recorded as Ca and Cb respectively. The calculation coefficients ka=Ca / MTS, kb=Cb / MTS; the value range of ka and kb must be -1 to 2, and ka≠kb, that is, the air magnetic barriers on both sides are asymmetric.

[0017] Preferably, the center lines of two adjacent layers of side permanent magnets form an angle a with the center of the rotor body, and the angle a between each two layers is not equal. Reasonable permanent magnet distribution angle is conducive to making the air gap magnetic field more sinusoidal, thereby reducing torque pulsation.

[0018] Preferably, in each permanent magnet group, the middle permanent magnets in different layers are parallel to each other, and their placement direction is perpendicular to the symmetry center line; the side permanent magnets on the same side in different layers are parallel to each other, and their placement direction is parallel to the inter-pole center line. The permanent magnets are all rectangular, which is convenient for the production, processing and assembly of permanent magnets.

[0019] Preferably, the thickness of the middle segment permanent magnets and the side permanent magnets gradually increases from the outer layer to the inner layer, and the width gradually increases from the outer layer to the inner layer; or, the sum of the areas of the middle segment permanent magnets and the side permanent magnets of each layer gradually increases from the outer layer to the inner layer. Larger and thicker middle segment permanent magnets and side permanent magnets can make the magnetic flux φ provided by the inner layer of the rotor 内 Greater than the outer magnetic flux φ 外 , and the magnetic flux between the two layers (φ 内 -φ 外) is greater than 0, ensuring the magnetic flux saturation of the external magnetic bridge and the internal magnetic bridge between each layer of permanent magnets, ensuring that there is a suitable magnetic flux in each layer of the rotor magnetic grid, and then ensuring that the permanent magnet magnetic flux in the air gap tends to be sinusoidal, obtaining a more sinusoidal permanent magnet back EMF, thereby reducing the motor torque fluctuation, increasing the average torque of the motor, reducing the vibration noise of the motor, and improving the performance of the motor under light load conditions.

[0020] Preferably, in each permanent magnet group, the rotor magnetic grids between two adjacent layers of permanent magnet units have different thicknesses in different layers. This design keeps the magnetic density of the same layer of magnetic grids basically consistent, optimizes the magnetic flux linkage, and ensures torque output.

[0021] Preferably, in each permanent magnet group, an internal magnetic bridge is provided between the middle segment permanent magnets and the side permanent magnets in some permanent magnet units.

[0022] The external magnetic bridge is between the air slot magnetic barrier and the outer circumference of the rotor body, and the total thickness of the internal magnetic bridge + the external magnetic bridge of each layer gradually increases from the outside to the inside.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention increases the motor salient pole ratio and improves the reluctance torque by rationally arranging multiple layers of permanent magnets and designing the shape and size of the corresponding rotor magnetic grid and air slot magnetic barrier, and adds side permanent magnets on both sides of the middle section permanent magnet. By arranging more permanent magnets to increase the permanent magnet torque, the torque density of the motor is improved. At the same time, the difficulty of motor control is significantly reduced, the stability of motor operation is improved, and the manufacturing cost can be reduced.

[0025] 2. The present invention can significantly reduce torque pulsation and reduce the vibration noise of the motor through the reasonable arrangement of air slot magnetic barriers. The special design of air slot magnetic barriers can weaken the reverse magnetic field under high current, increase the anti-demagnetization ability of permanent magnets, and reduce the failure risk caused by motor demagnetization. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of a high magnetic flux asymmetric magnetic barrier motor rotor structure according to an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the dimensions of a high-flux asymmetric magnetic barrier motor rotor structure according to an embodiment of the present invention;

[0028] Figure 3 This is another size schematic diagram of a high magnetic flux asymmetric magnetic barrier motor rotor structure according to an embodiment of the present invention;

[0029] Figure 4 It is a partial schematic diagram of the air slot magnetic barrier in an embodiment of the present invention;

[0030] Figure 5 Schematic diagram of the dimensions of the air slot magnetic barrier in an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be pointed out that the embodiments described below are intended to facilitate the understanding of the present invention and do not have any limiting effect on the present invention.

[0032] The purpose of the present invention is to improve the salient pole ratio Lq / Ld of the motor to improve the reluctance torque of the motor through the topological design of the permanent magnet assisted synchronous reluctance motor rotor, and to increase the side permanent magnets on both sides of the middle section permanent magnet, and to increase the permanent magnet torque of the motor by using as many permanent magnets as possible, thereby increasing the torque density of the motor. In addition, the position and shape structure of the air magnetic barrier are reasonably arranged in the design to reduce the torque pulsation of the motor and reduce the vibration noise when the motor is running. At the same time, the design can improve the working point of the permanent magnet and improve the anti-demagnetization ability of the permanent magnet to increase the operating reliability of the motor.

[0033] like Figure 1 As shown, this example takes the rotor structure of a 4-pole permanent magnet assisted synchronous reluctance motor as an example, including a rotor body 1 and a plurality of permanent magnet groups uniformly arranged on the rotor body in the circumferential direction; each permanent magnet group includes 4 layers of permanent magnet units from the inside to the outside. Each layer of permanent magnet units includes a middle section permanent magnet of a rectangular structure and symmetrical side permanent magnets on both sides.

[0034] Specifically, in this embodiment, 4 layers of middle permanent magnets are provided, which are middle permanent magnets 111, 112, 113, and 114 from outside to inside. The side permanent magnets are installed in the air slots provided on both sides of the middle section permanent magnets, which are side permanent magnets 121, 122, 123, and 124 from outside to inside. The air slot area outside the side permanent magnets constitutes air slot magnetic barriers, which are air slot magnetic barriers 141, 142, 143, and 144 from outside to inside. The rotor magnetic grids are between two adjacent layers of permanent magnet units, the outer side of the outermost layer of permanent magnet units, and the inner side of the innermost layer of permanent magnet units, which are rotor magnetic grids 131, 132, 133, 134, and 135 from outside to inside.

[0035] like Figure 3As shown, the air slot magnetic barriers 141-144 are conical, and for each air slot magnetic barrier, its thickness gradually decreases from the inside to the outside, that is, BT2>BT1. Corresponding to the rotor magnetic grids 132-134 between the two layers of magnetic barriers, each rotor magnetic grid gradually widens from the inside to the outside, that is, GT2<GT1. The conical design can make the transition of the rotor magnetic barrier position smooth and prevent the output performance loss caused by the sudden change of the magnetic field. The thickness BT1 of the magnetic barrier close to the outer circle accounts for the smallest proportion, which can make the reasonable distribution of the air gap magnetic density at the outer circle of the rotor closer to the sine and reduce the torque pulsation. At the same time, the thickness BT1 of the magnetic barrier close to the outer circle is reduced, that is, the magnetic resistance between the layers is reduced, so that the magnetic resistance in the air slot magnetic barrier is smaller than the magnetic resistance at the side permanent magnet position, which is conducive to the d-axis reverse demagnetization magnetic field passing more from the air slot magnetic barrier position with smaller magnetic resistance, and less d-axis demagnetization magnetic field flows through the side permanent magnet, thereby improving the anti-demagnetization performance of the permanent magnet.

[0036] The width ratio of the air slot magnetic barrier and the side permanent magnet can be adjusted. Figure 3 As shown, in each layer of permanent magnet units, the actual width of the side permanent magnet is recorded as MWS, the sum of the widths of the side permanent magnet and the air slot magnetic barrier (i.e., the theoretical maximum width of the side permanent magnet) is recorded as LWS, and the ratio of MWS to LWS is recorded as the coefficient Kw. Except for the outermost layer of permanent magnet units, other layers must satisfy 0.3≤Kw≤0.9, and the coefficient Kw of the inner layer permanent magnet units is greater than that of the outer layer.

[0037] The arrangement of the side permanent magnets can effectively improve the permanent magnet flux linkage of the motor and the output of permanent magnet torque. Its width ratio Kw is adjustable, which can provide optimization space for a more reasonable magnetic circuit arrangement and find the optimal solution for motor output performance in different topologies. Combined with the selection of magnetic steel grades and working points of magnetic steel, different rotor topologies can achieve a balance between output performance and magnetic steel reliability.

[0038] The position of the air slot magnetic barrier on the outer circle can be adjusted. The present invention proposes a method for defining the air slot magnetic barrier, such as Figure 4 In the figure, the thickness of the second layer of the side permanent magnet 122 is MTS2, the extension lines 122a-e and 122b-e of the side permanent magnet 122 of this layer close to the symmetry center line 17, the outer arc center lines 142a-m and 142b-m of the air slot magnetic barrier 142, and the center lines 122a-m and 122b-m of the side permanent magnet. The distance between the extension line 122a-e and the outer arc center line 142a-m is C2a, and the distance between the extension line 122b-e and the outer arc center line 142b-m is C2b, then k2a=C2a / MTS2, k2b=C2b / MTS2, k2a and k2b are usually not equal. On the basis of ensuring GT1>GT2, the value range of ka and kb can be adjusted at will, and the value may be less than 0 or greater than 1, which means that the center line of the air slot magnetic barrier is outside the thickness range of the permanent magnet, such as Figure 5k4a in is less than 0. In this design, the k of each layer is not equal, and the ka and kb on both sides of the same layer are not equal, that is, the air magnetic barriers on both sides are asymmetric. The usual value range of ka and kb is -1 to 2, which makes the position arrangement of the air slot magnetic barrier have a large adjustment space, so that more solutions can be explored when optimizing the motor torque pulsation.

[0039] An arc segment parallel to the outer circle is arranged on the outer side of the air slot magnetic barrier, and the tapered segment and the arc segment are transitioned by fillets Ra and Rb.

[0040] The center lines of the two adjacent layers of side permanent magnets form an angle a with the center of the outer circle at the intersection point, such as Figure 3 As shown, the angle between the side permanent magnet 121 and the symmetry line 17 is a1, and the angle between the side permanent magnet 121 and the side permanent magnet 122 is a2. The angle a between each two layers of magnetic barriers is not equal, that is, a1≠a2≠a3≠a4. Reasonable permanent magnet distribution angle is conducive to the air gap magnetic field being more sinusoidal, thereby reducing torque pulsation.

[0041] like Figure 1 As shown, the middle section permanent magnets 111-114 are parallel to each other, and their placement direction is perpendicular to the center line 17. The side permanent magnets 121-124 on the same side are also parallel to each other, and their placement direction is parallel to the inter-pole center line 18.

[0042] like Figure 2 As shown, for the middle segment permanent magnets 111-114 and the side permanent magnets 121-124, the thickness of the permanent magnets gradually increases from the outside to the inside, that is, MT1≤MT2≤MT3≤MT4, MTS1≤MTS2≤MTS3≤MTS4, and the permanent magnet width MW1≤MW2≤MW3≤MW4, MWS1≤MWS2≤MWS3≤MWS4. The larger and thicker middle segment permanent magnets and side permanent magnets can make the magnetic flux φinside provided by the inner layer of the rotor larger than the magnetic flux φoutside of the outer layer, and the magnetic flux (φinside-φoutside) between the two layers is greater than 0, ensuring that the magnetic flux density of the external magnetic bridge and the internal magnetic bridge between each layer of permanent magnets is saturated, ensuring that there is a suitable magnetic flux in each layer of the rotor magnetic grid, and then ensuring that the permanent magnetic flux density in the air gap tends to be sinusoidal, obtaining a more sinusoidal permanent magnetic back electromotive force, thereby reducing the motor torque fluctuation, improving the average torque of the motor, reducing the vibration noise of the motor, and improving the performance of the motor under light load conditions.

[0043] The thickness of the rotor magnetic grids 131-135 between two layers of permanent magnets is not necessarily the same from the first layer to the nth layer, that is, MC1≠MC2≠MC3≠MC4≠MC5, MCS1≠MCS2≠MCS3≠MCS4≠MCS5.

[0044] like Figure 1As shown, in each permanent magnet group, an internal magnetic bridge is set between the middle segment permanent magnet and the side permanent magnet in some permanent magnet units, and the internal magnetic bridge can also be cancelled if the rotor strength allows. For example, there is no internal magnetic bridge between the middle segment permanent magnet 111 and the side permanent magnet 121, MG=0; internal magnetic bridges 162-164 are set between the middle segment permanent magnets 112-114 and the corresponding side permanent magnets 122-124, MG≠0.

[0045] External magnetic bridges 151 to 154 are located between the air slot magnetic barriers and the outer circumference of the rotor body. The total thickness of each layer of internal magnetic bridges + external magnetic bridges increases gradually from the outside to the inside.

[0046] The rotor structure designed by the present invention can support a multi-layer permanent magnet structure, and provide a multi-dimensional parametric design of the position and shape size of the middle section permanent magnet, the side permanent magnet, the rotor magnetic grid and the air slot magnetic barrier, providing a rich degree of freedom for the design to find a suitable solution, thereby improving the magnetic resistance torque ratio, increasing the torque output, and obtaining a lower torque pulsation. At the same time, the special design of the air slot magnetic barrier can well bear and weaken the reverse magnetic field under high current, reducing the risk of permanent magnet demagnetization.

[0047] The embodiments described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high flux asymmetric magnetic barrier motor rotor structure, characterized in that: It comprises a rotor body and a plurality of permanent magnet groups uniformly arranged on the rotor body in a circumferential direction; Each permanent magnet group includes n layers of permanent magnet units from the inside to the outside in the radial direction, and each layer of permanent magnet units includes a middle section permanent magnet of a rectangular structure and symmetrical side permanent magnets on both sides; the side permanent magnets are installed in air slots arranged on both sides of the middle section permanent magnet, and the air slot area outside the side permanent magnets constitutes an air slot magnetic barrier; The rotor magnetic grid is located between two adjacent layers of permanent magnet units, outside the outermost layer of permanent magnet units, and inside the innermost layer of permanent magnet units; each air slot magnetic barrier is tapered with a thickness gradually decreasing from the inside to the outside, and the air magnetic barriers on both sides corresponding to each layer of permanent magnet units are asymmetric; the rotor magnetic grid portion corresponding to the two adjacent layers of air slot magnetic barriers gradually widens from the inside to the outside; The outer side of the conical section of the air slot magnetic barrier is provided with an arc section parallel to the outer circle of the rotor body, and the conical section and the arc section are transitioned by a fillet; in each layer of permanent magnet units, the thickness of the side permanent magnet is recorded as MTS, and the distances between the two side extension lines of the two side permanent magnets close to the symmetry center line and the outer arc center line of the corresponding air slot magnetic barrier are recorded as Ca and Cb respectively, and the calculation coefficients ka=Ca / MTS, kb=Cb / MTS; the value range of ka and kb must be -1 to 2, and ka≠kb, that is, the air magnetic barriers on both sides are asymmetric; An angle a is formed between the center lines of two adjacent layers of side permanent magnets and the center of the rotor body, and the angle a between every two layers is not equal.

2. The high magnetic flux asymmetric magnetic barrier motor rotor structure according to claim 1, characterized in that: In each layer of permanent magnet units, the width of the side permanent magnet is recorded as MWS, the sum of the widths of the side permanent magnet and the air slot magnetic barrier is recorded as LWS, and the ratio of MWS to LWS is recorded as the coefficient Kw. Except for the outermost layer of permanent magnet units, other layers must satisfy 0.3≤Kw≤0.9, and the coefficient Kw of the inner layer permanent magnet unit is greater than that of the outer layer.

3. The high magnetic flux asymmetric magnetic barrier motor rotor structure according to claim 1, characterized in that: In each permanent magnet group, the middle permanent magnets in different layers are parallel to each other, and their placement direction is perpendicular to the symmetry center line; the side permanent magnets on the same side in different layers are parallel to each other, and their placement direction is parallel to the inter-pole center line.

4. The high magnetic flux asymmetric magnetic barrier motor rotor structure according to claim 1, characterized in that: The thickness of the middle section permanent magnet and the side permanent magnet gradually increases from the outer layer to the inner layer, and the width gradually increases from the outer layer to the inner layer; or, the sum of the areas of the middle section permanent magnet and the side permanent magnet of each layer gradually increases from the outer layer to the inner layer.

5. The high magnetic flux asymmetric magnetic barrier motor rotor structure according to claim 1, characterized in that: In each permanent magnet group, the rotor magnetic grids between two adjacent layers of permanent magnet units have different thicknesses in different layers.

6. The high magnetic flux asymmetric magnetic barrier motor rotor structure according to claim 1, characterized in that: In each permanent magnet group, an internal magnetic bridge is arranged between the middle section permanent magnet and the side permanent magnet in some permanent magnet units.

7. The high magnetic flux asymmetric magnetic barrier motor rotor structure according to claim 6, characterized in that: The external magnetic bridge is between the air slot magnetic barrier and the outer circumference of the rotor body, and the total thickness of the internal magnetic bridge + the external magnetic bridge of each layer gradually increases from the outside to the inside.

Images