Motor rotors, reluctance motors and electric vehicles

Abstract

The present application provides a motor rotor, a reluctance motor and an electric vehicle. The motor rotor comprises a rotor core (1), the rotor core (1) comprises an inner ring portion (2) and an outer ring portion (3), the inner ring portion (2) is provided with a plurality of magnetic barrier groups along the circumferential direction, each magnetic barrier group comprises at least two inner magnetic flux barriers (4) arranged at intervals along the radial direction, an inner magnetic conduction channel (5) is formed between two adjacent inner magnetic flux barriers (4), the outer ring portion (3) is provided with a plurality of outer magnetic flux barriers (6) arranged at intervals along the circumferential direction, an outer magnetic conduction channel (7) extending along the radial direction is formed between adjacent outer magnetic flux barriers (6). According to the motor rotor of the present application, the air gap waveform of the reluctance motor can be changed, the waveform can be optimized, the sinusoidal degree can be increased, the motor efficiency can be improved, and the motor torque pulsation can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of motor equipment, and in particular to a motor rotor, a reluctance motor and an electric vehicle. Background Art

[0002] Motors are an important part of modern society. Every year, motor power consumption accounts for more than 30% of the electricity consumption of human society. High-efficiency permanent magnet synchronous motors require the use of rare resources, rare earth metals. It is difficult to achieve a significant breakthrough in the energy efficiency of asynchronous motors using conventional materials. The rotor of the permanent magnet assisted synchronous reluctance motor has multiple layers of magnetic barriers, in which ferrite magnets are placed. It has a high efficiency close to that of rare earth permanent magnet motors, and the cost is much lower than that of rare earth motors, which can solve this problem well.

[0003] The rotor of the permanent magnet assisted synchronous reluctance motor is composed of multiple rotor laminations. Each rotor lamination is provided with multiple layers of air slots, called magnetic barriers, in which certain permanent magnets are placed. There is a magnetic channel between every two layers of magnetic barriers. The magnetic field passes through the air gap through the magnetic channel on the outer circle of the rotor and then leads to the stator teeth. The quality of the air gap magnetic flux waveform depends to a large extent on the arrangement of the magnetic barriers. The difference in the sinusoidality of the air gap magnetic flux waveform will lead to large iron loss of the motor, reduced efficiency, and increased torque pulsation. Limited by the rotor space and processing difficulty, the number of magnetic barrier layers and the placement adjustment space of the permanent magnet assisted synchronous reluctance motor are not large, so it is difficult to effectively reduce iron loss, improve energy efficiency, and weaken torque pulsation. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present application is to provide a motor rotor, a reluctance motor and an electric vehicle, which can change the air gap waveform of the reluctance motor, optimize the waveform, increase the sinusoidality, improve the motor efficiency and reduce the motor torque pulsation.

[0005] In order to solve the above problems, the present application provides a motor rotor, including a rotor core, the rotor core including an inner ring portion and an outer ring portion, the inner ring portion is provided with a plurality of magnetic barrier groups along the circumferential direction, each magnetic barrier group includes at least two inner magnetic flux barriers arranged at intervals along the radial direction, an inner magnetic conductive channel is formed between two adjacent inner magnetic flux barriers, and the outer ring portion is provided with a plurality of outer magnetic flux barriers arranged at intervals along the circumferential direction, an outer magnetic conductive channel extending radially is formed between adjacent outer magnetic flux barriers.

[0006] Preferably, the number of outer flux barriers is greater than twice the number of inner flux barriers.

[0007] Preferably, the inner magnetic conductive channel and the outer magnetic conductive channel on the radial outside thereof extend in the same direction.

[0008] Preferably, a permanent magnet is disposed inside the inner magnetic flux barrier, and the inner magnetic conductive channel extends along the Q-axis direction.

[0009] Preferably, the outer magnetic conductive channel is parallel to the D-axis direction of the pole where it is located.

[0010] Preferably, a chamfered edge is provided on a side of the radial outer edge of the outer magnetic flux barrier close to the D axis.

[0011] Preferably, the angle between the center line of the outer magnetic flux barrier and the D axis is ω, where 0°≤ω≤20°.

[0012] Preferably, the number of layers of the outer magnetic flux barrier is C1, the number of layers of the inner magnetic flux barrier is C2, and the greatest common divisor of C1 and C2 GCD(C1, C2)=1.

[0013] Preferably, the inner magnetic flux barrier is V-shaped, and the permanent magnets are arranged in the two side grooves of the inner magnetic flux barrier; or, the inner magnetic flux barrier is flat-bottomed V-shaped, and the permanent magnets are arranged in the two side grooves of the inner magnetic flux barrier; or, the inner magnetic flux barrier is flat-bottomed V-shaped, and the permanent magnets are arranged in the bottom groove of the inner magnetic flux barrier; or, the inner magnetic flux barrier is U-shaped, and the permanent magnets are arranged in the two side grooves of the inner magnetic flux barrier; or, the inner magnetic flux barrier is U-shaped, and the permanent magnets are arranged in the bottom groove of the inner magnetic flux barrier.

[0014] According to another aspect of the present application, a reluctance motor is provided, comprising a motor rotor and a motor stator, wherein the motor rotor is the above-mentioned motor rotor.

[0015] Preferably, when the motor rotor includes a beveled edge, the motor stator includes a stator tooth shoe, the outlet width of the outer magnetic conductive channel is wd, and the inner circumferential wall width of the stator tooth shoe is wt, wherein 0.25wt≤wd≤0.4wt.

[0016] Preferably, the number of layers of the external magnetic flux barrier is C1, the number of stator teeth of the motor stator is Z, and the greatest common divisor of C1 and Z is GCD(Z, C1), where GCD(Z, C1)≤3.

[0017] According to another aspect of the present application, an electric vehicle is provided, comprising the above-mentioned motor rotor or the above-mentioned reluctance motor.

[0018] The motor rotor provided in the present application includes a rotor core, and the rotor core includes an inner ring part and an outer ring part. The inner ring part is provided with a plurality of magnetic barrier groups along the circumferential direction, and each magnetic barrier group includes at least two inner magnetic flux barriers spaced apart in the radial direction, and an inner magnetic conductive channel is formed between two adjacent inner magnetic flux barriers. The outer ring part is provided with a plurality of outer magnetic flux barriers spaced apart in the circumferential direction, and an outer magnetic conductive channel extending in the radial direction is formed between adjacent outer magnetic flux barriers. By dividing the rotor core into two regions, the inner ring part and the outer ring part, along the radial direction, the characteristic of the relatively large space of the outer circle of the rotor can be utilized to perform different structural designs for the magnetic conductive channels of the inner ring part and the outer ring part, and the magnetic flux barriers and the magnetic conductive channels of the outer ring part can be planned according to the structure of the magnetic flux barriers and the magnetic conductive channels of the inner ring part, so that the number of layers and the placement position of the magnetic flux barriers of the outer ring part can be optimized, thereby changing the air gap waveform, optimizing the waveform, increasing the sinusoidality, improving the motor efficiency, and reducing the torque pulsation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the structure of a motor rotor according to an embodiment of the present application;

[0020] Figure 2 This is a schematic diagram of the structure of the magnetic conductive channel of the motor rotor according to an embodiment of the present application;

[0021] Figure 3 A structural diagram of the external magnetic flux barrier of the motor rotor of an embodiment of the present application;

[0022] Figure 4 A schematic diagram of the structure of a motor rotor according to another embodiment of the present application;

[0023] Figure 5 This is a schematic structural diagram of a motor rotor according to another embodiment of the present application;

[0024] Figure 6 This is a dimensional structure diagram of the motor rotor of an embodiment of the present application;

[0025] Figure 7 A comparison diagram of air gap magnetic flux density of motor rotors with different numbers of external magnetic flux barrier layers according to an embodiment of the present application;

[0026] Figure 8 This is a diagram showing the influence of the number of outer magnetic flux barrier layers on the torque ripple of the motor rotor according to an embodiment of the present application;

[0027] Fig. 9 This is a diagram showing the influence of the turning angle of the external magnetic flux barrier of the motor rotor on the torque output according to an embodiment of the present application;

[0028] Fig.10 This is a curve chart showing the influence of the ratio of the tooth width of the motor rotor to the outlet width of the outer magnetic conductive channel on the torque pulsation of the embodiment of the present application.

[0029] The reference numerals are:

[0030] 1. Rotor core; 2. Inner ring; 3. Outer ring; 4. Inner magnetic flux barrier; 5. Inner magnetic channel; 6. Outer magnetic flux barrier; 7. Outer magnetic channel; 8. Bevel edge; 9. Permanent magnet; 10. Motor stator; 11. Stator tooth shoe. DETAILED DESCRIPTION

[0031] See also Figures 1 to 10 As shown, according to an embodiment of the present application, the motor rotor includes a rotor core 1, the rotor core 1 includes an inner ring portion 2 and an outer ring portion 3, the inner ring portion 2 is provided with a plurality of magnetic barrier groups along the circumferential direction, each magnetic barrier group includes at least two inner magnetic flux barriers 4 arranged at intervals along the radial direction, an inner magnetic conduction channel 5 is formed between two adjacent inner magnetic flux barriers 4, the outer ring portion 3 is provided with a plurality of outer magnetic flux barriers 6 arranged at intervals along the circumferential direction, and an outer magnetic conduction channel 7 extending in the radial direction is formed between adjacent outer magnetic flux barriers 6. The inner magnetic flux barriers 4 and the outer magnetic flux barriers 6 are arranged at intervals along the radial direction.

[0032] In this embodiment, the radial inner walls of each outer flux barrier 6 are located on the same circumference, the radial outer walls of each inner flux barrier 4 are located on the same circumference, and the circumferential diameter of the outer flux barrier 6 is greater than the circumferential diameter of the inner flux barrier 4.

[0033] The air gap magnetic flux waveform is determined by the synthesis of the rotor magnetic field and the stator magnetic field. For permanent magnet assisted synchronous reluctance motors, the number of stator teeth is usually greater than the number of rotor magnetic barrier layers. Therefore, the sinusoidality of the air gap magnetic field waveform is poor, the harmonic content is relatively high, the harmonic loss is large, and the torque pulsation is high. At the same time, the area facing the stator and rotor magnetic fields is small, and there is more leakage magnetic flux, resulting in low torque output and low efficiency.

[0034] The present application divides the rotor core 1 into two areas, an inner ring portion 2 and an outer ring portion 3, along the radial direction. By utilizing the relatively large space of the rotor outer circle, different structural designs can be made for the magnetic channels of the inner ring portion 2 and the outer ring portion 3. The magnetic flux barriers and magnetic channels of the outer ring portion 3 can be planned according to the structures of the magnetic flux barriers and magnetic channels of the inner ring portion 2. The number of layers and placement of the magnetic flux barriers of the outer ring portion 3 can be optimized, thereby overcoming the problem of too few rotor magnetic barrier layers in the prior art, and being able to more effectively change the air gap waveform, optimize the waveform, increase the sinusoidality, improve the motor efficiency, and reduce the torque pulsation.

[0035] Preferably, the number of external flux barriers 6 is greater than twice the number of internal flux barriers 4. In this embodiment, under the same pole, the number of external flux barriers 6 is the total number of external flux barriers 6 located under the pole, and the number of internal flux barriers 4 is the number of layers of internal flux barriers 4 arranged in the radial direction. Since external flux barriers 6 are arranged at both ends of each internal flux barrier 4, the number of external flux barriers 6 is greater than twice the number of internal flux barriers 4, which can ensure that the number of external flux barriers 6 at both ends of the internal flux barrier 4 is greater than the number of layers of the internal flux barrier 4, thereby utilizing the advantage of a larger number of external flux barriers 6 to optimize the air gap flux density at the intersection of the rotor magnetic field and the stator magnetic field, and at the same time changing the relationship between the number of stator slots and the number of rotor flux barrier layers, so as to achieve the purpose of optimizing the air gap flux density and reducing torque pulsation, such as Figure 8 shown.

[0036] For the external magnetic flux barriers 6, the number of layers of the external magnetic flux barriers 6 refers to the number of the external magnetic flux barriers 6 located on one side of the center line of the pole under the same pole.

[0037] The inner magnetic conductive channel 5 extends in the same direction as the outer magnetic conductive channel 7 on its radial outside, so that the extension directions of the inner and outer magnetic conductive channels can be more consistent while changing the waveform of the air gap between the stator and the rotor, thereby ensuring that the magnetic lines of force can pass through the air gap more quickly and effectively, reducing leakage flux and improving the working efficiency of the motor.

[0038] In this embodiment, a permanent magnet 9 is disposed in the inner magnetic flux barrier 4, and the inner magnetic conductive channel 5 extends along the Q axis. By disposing the permanent magnet 9, the permanent magnet 9 can be used to assist the reluctance motor, thereby improving the motor efficiency and power factor.

[0039] The permanent magnet assisted synchronous reluctance motor rotor of the present application is formed by stacking multiple rotor punchings, each rotor punching has multiple air slots punched out, called magnetic barriers, a certain amount of ferrite permanent magnets are placed in the magnetic barriers, and there are silicon steel sheets between every two layers of magnetic barriers, called magnetic channels, and magnetic channels and magnetic barriers always appear in pairs. Ferrite magnets are placed in the magnetic barriers of the rotor of the permanent magnet assisted synchronous reluctance motor to generate a rotor magnetic field, which passes along the direction of the magnetic channels, passes through the magnetic channels of the two arms, and finally passes through the magnetic channels of the outer circle of the rotor into the air gap.

[0040] Preferably, the outer magnetic conductive channel 7 is parallel to the D-axis direction of the pole where it is located, so that the magnetic field can smoothly enter or flow out of the motor rotor through the air gap, reduce the magnetic field flow resistance, improve the magnetic field flow efficiency, improve the motor working performance, and improve the motor output torque.

[0041] A chamfered edge 8 is provided on the radial outer edge of the outer flux barrier 6 near the D axis. The chamfered edge 8 can guide the intersection of the rotor magnetic field and the stator magnetic field, thereby effectively optimizing the torque pulsation and reducing the rotation noise of the motor.

[0042] The angle between the center line of the external magnetic flux barrier 6 and the D axis is ω, where 0°≤ω≤20°, thereby avoiding the excessive magnetic field flow resistance caused by the angle between the center line of the external magnetic flux barrier 6 and the D axis, thereby reducing the adverse effect of the external magnetic flux barrier 6 on the motor output torque.

[0043] The number of layers of the outer flux barrier 6 is C1, the number of layers of the inner flux barrier 4 is C2, and the greatest common divisor of C1 and C2 GCD(C1, C2)=1, which can increase the number of cycles of magnetic field alternation, reduce the alternating amplitude, further optimize the air gap magnetic density and torque pulsation, more effectively reduce the torque pulsation, and improve the motor torque output. In this embodiment, the number of layers of the inner flux barrier 4 is 4, and the number of layers of the outer flux barrier 6 is 7.

[0044] In one embodiment, the inner flux barrier 4 is V-shaped, and the permanent magnets 9 are disposed in two side grooves of the inner flux barrier 4 .

[0045] In another embodiment, the inner magnetic flux barrier 4 is in a flat-bottomed V-shape, and the permanent magnets 9 are disposed in two side grooves of the inner magnetic flux barrier 4 .

[0046] In another embodiment, the inner magnetic flux barrier 4 is in a flat-bottomed V-shape, and the permanent magnet 9 is disposed in a bottom groove of the inner magnetic flux barrier 4 .

[0047] In another embodiment, the inner magnetic flux barrier 4 is U-shaped, and the permanent magnets 9 are disposed in two side grooves of the inner magnetic flux barrier 4 .

[0048] In another embodiment, the inner magnetic flux barrier 4 is U-shaped, and the permanent magnet 9 is disposed in a bottom groove of the inner magnetic flux barrier 4 .

[0049] In another embodiment, the inner magnetic flux barrier 4 is in a flat-bottomed V-shape, and the permanent magnets 9 are disposed in both the bottom groove and the two side grooves of the inner magnetic flux barrier 4 .

[0050] In other embodiments, the inner magnetic flux barrier 4 may also be in an arc shape, and the permanent magnets 9 may be disposed at both ends of the inner magnetic flux barrier 4 or at the bottom of the inner magnetic flux barrier 4 .

[0051] In the present application, since the setting of the inner magnetic flux barrier 4 must meet certain structural requirements to ensure that the magnetic lines of force can smoothly enter and exit the motor rotor through the inner magnetic channels 5 between the adjacent inner magnetic flux barriers 4, the magnetic direction of the inner magnetic channels 5 is often not optimal. The magnetic lines of force will pass through a large angle turn in the process of flowing out of or entering the inner magnetic channels 5, which will not only reduce the torque output, but also increase the torque pulsation. By setting the outer magnetic flux barrier 6 on the outer ring portion 3, the setting direction of the outer magnetic flux barrier 6 can be independent of the setting direction of the inner magnetic flux barrier 4, so that the magnetic direction of the outer magnetic channel 7 is different from that of the inner magnetic channel 5, and then by adjusting the magnetic direction of the outer magnetic channel 7, the turning angle in the flow process of the magnetic lines of force can be reduced, the flow resistance of the magnetic lines of force can be reduced, the torque output of the motor can be improved, and the torque pulsation can be reduced.

[0052] The permanent magnet 9 is, for example, a ferrite permanent magnet or a neodymium iron boron permanent magnet.

[0053] According to an embodiment of the present application, the reluctance motor includes a motor rotor and a motor stator 10 , and the motor rotor is the motor rotor mentioned above.

[0054] Preferably, when the motor rotor includes a beveled edge 8, the motor stator 10 includes a stator tooth shoe 11, the outlet width of the outer magnetic channel 7 is wd, and the inner circumferential wall width of the stator tooth shoe 11 is wt, wherein 0.25wt≤wd≤0.4wt, so that the outlet width of the outer magnetic channel 7 can be more matched with the inner circumferential wall width of the stator tooth shoe 11, thereby more effectively optimizing the torque pulsation.

[0055] The number of layers of the external flux barrier 6 is C1, the number of stator teeth of the motor stator 10 is Z, and the greatest common divisor of C1 and Z is GCD(Z, C1), where GCD(Z, C1)≤3. At this time, the air gap flux density and torque pulsation optimization effect of the motor is better, such as Figure 7 shown.

[0056] According to an embodiment of the present application, an electric vehicle includes the above-mentioned motor rotor or the above-mentioned reluctance motor.

[0057] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0058] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A motor rotor, characterized in that: The invention comprises a rotor core (1), wherein the rotor core (1) comprises an inner ring portion (2) and an outer ring portion (3), wherein the inner ring portion (2) is provided with a plurality of magnetic barrier groups along the circumferential direction, each magnetic barrier group comprises at least two inner magnetic flux barriers (4) arranged at intervals along the radial direction, an inner magnetic conduction channel (5) is formed between two adjacent inner magnetic flux barriers (4), and the outer ring portion (3) is provided with a plurality of outer magnetic flux barriers (6) arranged at intervals along the circumferential direction, an outer magnetic conduction channel (7) extending along the radial direction is formed between adjacent outer magnetic flux barriers (6); The outer magnetic flux barriers (6) are arranged at both ends of each of the inner magnetic flux barriers (4); The inner magnetic conductive channel (5) and the outer magnetic conductive channel (7) on the radial outside thereof extend in the same direction; The inner magnetic conductive channel (5) extends along the Q-axis direction; The outer magnetic conductive channel (7) is parallel to the D-axis direction of the pole where it is located.

2. The motor rotor according to claim 1, characterized in that: The number of the outer flux barriers (6) is greater than twice the number of the inner flux barriers (4).

3. The motor rotor according to claim 1 or 2, characterized in that: A permanent magnet (9) is arranged inside the inner magnetic flux barrier (4).

4. The motor rotor according to claim 1, characterized in that: A chamfered edge (8) is provided on a side of the radial outer edge of the outer magnetic flux barrier (6) close to the D axis.

5. The motor rotor according to claim 1, characterized in that: The included angle between the center line of the outer magnetic flux barrier (6) and the D axis is ω, wherein 0°≤ω≤20°.

6. The motor rotor according to claim 1, characterized in that: The number of layers of the outer magnetic flux barrier (6) is C1, the number of layers of the inner magnetic flux barrier (4) is C2, and the greatest common divisor of C1 and C2 GCD(C1, C2)=1.

7. The motor rotor according to claim 3, characterized in that: The inner magnetic flux barrier (4) is V-shaped, and the permanent magnet (9) is arranged in two side grooves of the inner magnetic flux barrier (4); or, the inner magnetic flux barrier (4) is flat-bottomed V-shaped, and the permanent magnet (9) is arranged in two side grooves of the inner magnetic flux barrier (4); or, the inner magnetic flux barrier (4) is flat-bottomed V-shaped, and the permanent magnet (9) is arranged in the bottom groove of the inner magnetic flux barrier (4); or, the inner magnetic flux barrier (4) is U-shaped, and the permanent magnet (9) is arranged in two side grooves of the inner magnetic flux barrier (4); or, the inner magnetic flux barrier (4) is U-shaped, and the permanent magnet (9) is arranged in the bottom groove of the inner magnetic flux barrier (4).

8. A reluctance motor, comprising a motor rotor and a motor stator (10), characterized in that: The motor rotor is the motor rotor according to any one of claims 1 to 7.

9. The reluctance motor according to claim 8, characterized in that: When the motor rotor includes a beveled edge (8), the motor stator (10) includes a stator tooth shoe (11), the outlet width of the external magnetic conductive channel (7) is wd, and the inner peripheral wall width of the stator tooth shoe (11) is wt, wherein 0.25wt≤wd≤0.4wt.

10. The reluctance motor according to claim 8, characterized in that: The number of layers of the external magnetic flux barrier (6) is C1, the number of stator teeth of the motor stator (10) is Z, and the greatest common divisor of C1 and Z is GCD (Z, C1), wherein GCD (Z, C1) ≤ 3.

11. An electric vehicle, characterized in that: The invention comprises the motor rotor according to any one of claims 1 to 7 or the reluctance motor according to any one of claims 8 to 10.

Images