A rotary electrical machine

Abstract

A rotary electric motor (100) has: a stator (110) having a plurality of slots (112) for winding; and a rotor (120) having an even number of magnetic poles (122). The rotor (120) is rotatably engaged with the stator (110). Each of the magnetic poles (122) includes at least three magnets, wherein a first set (124) of at least two magnets is configured in a substantially V-shaped configuration and a second set (128) of at least one magnet is disposed between the first set (124) of magnets and an outer periphery (132) of the rotor (120). In addition, at least one flux barrier (126) is located between the first assembly (124) of the magnet and the outer periphery (132) of the rotor (120), and at least one flux barrier (130) is located between the second assembly (128) of the magnet and the outer periphery (132) of the rotor (120).

Description

[Technical Field]

[0001] This invention relates to a rotary electric motor. [Previous Technology]

[0002] A typical rotating electric machine consists of a stator and a rotor. Due to the relative motion between the rotor and the magnetic field generated by the stator, a back electromotive force (EMF) is produced. Due to mechanical limitations and design considerations of the rotor and stator, the back EMF does not perfectly match an ideal sinusoidal waveform and contains several harmonics. These harmonics cause additional heat in the machine.

[0003] The stator windings of rotating machines can be star-connected or delta-connected. However, in the case of a delta connection, the voltage waveform in the stator winding has higher levels of harmonics. These higher levels of harmonics cause circulating currents to form within the delta connection of the windings. Such circulating currents cause additional heat, thereby causing the machine to heat up beyond safe and operable levels. Therefore, considering the heat generated by harmonics present in the back electromotive force, the use of delta connections for stator windings is limited. Therefore, in order to adopt and utilize delta connections, it becomes necessary to minimize the harmonics in the back electromotive force to obtain a more sinusoidal waveform.

[0004] Furthermore, in the conventional rotor design of rotating machines, the torque characteristics exhibit increased ripple. This increased ripple generates cogging torque. When the cogging torque is high, the rotating machine experiences higher levels of obstruction during the forward and backward movement of the rotor. This also causes an undesirable waveform of the back electromotive force, in which the back electromotive force contains significant harmonics and the waveform is not purely sinusoidal.

[0005] The torque characteristics of conventional rotor designs, which exhibit increased ripple, also depend on the combination of magnets in the rotor of the rotating machine. Specifically, in the 6-pole and 36-slot variants of distributed winding combinations in rotating machines, torque ripple increases with the increase in machine significance. Significance is defined as a measurement of the difference in magnetic reluctance between the rotor and the stator surrounding the rotor's circumference. Higher significance has a detrimental effect on causing undesirable waveform torque ripple, and therefore, in this respect, it is not possible to use delta connections in the stator windings, thus limiting the rotating machine.

[0006] Another problem with the design of rotors in conventional rotating machines is that the permanent magnets used in the rotor are not common, that is, the permanent magnets required in different configurations such as V configuration or delta configuration are different. Therefore, different permanent magnets need to be produced for different configurations of permanent magnets in the rotor, which increases manufacturing and assembly costs.

[0007] In addition, the saturation of the laminated core is another common limitation in the rotor design of conventional rotating machines.

[0008] Therefore, this technology requires a rotary motor that can solve at least the aforementioned problems. [Summary of the Invention]

[0009] This invention relates to a rotating electric motor having: a stator having a plurality of slots for winding; and a rotor having an even number of magnetic poles. The rotor and stator are rotatably engaged. Each of the magnetic poles of the rotor has at least three magnets, wherein a first set of at least two magnets is configured in a substantially V-shaped configuration and a second set of at least one magnet is configured between the first set of magnets and the outer periphery of the rotor. Furthermore, at least one flux barrier is positioned between the first set of magnets and the outer periphery of the rotor, and at least one flux barrier is positioned between the second set of magnets and the outer periphery of the rotor.

[0010] In an embodiment of the present invention, the rotor has a plurality of recesses on its outer periphery.

[0011] In another embodiment of the present invention, each of the two magnets in the first set has a first end and a second end, wherein the first ends of each of the magnets in the first set are adjacent to each other.

[0012] In another embodiment of the invention, the first ends of each magnet in the first set are adjacent to each other with a gap between them.

[0013] In another embodiment of the present invention, the pole numbered n={2K+1,K≥0} has a first set of two magnets arranged in a substantially V-shaped configuration symmetrically along the central axis A-A' of the pole, a second set of one magnet disposed between the first set and the outer periphery of the rotor, and two flux barriers. Herein, the first end of each flux barrier is positioned at a first angle (θ1) from the second end of each magnet in the first set, and the second end of each flux barrier is positioned adjacent to the outer periphery of the rotor. Furthermore, the first end of each flux barrier is positioned at a third angle (θ3) from each end of the second set of one magnet, and the second end of each flux barrier is positioned adjacent to the outer periphery of the rotor.

[0014] In another embodiment of the present invention, the pole numbered n={2K,K≥1} has a first set of two magnets arranged in a substantially V-shaped configuration symmetrically along the central axis B-B' of the pole, a second set of one magnet disposed between the first set and the outer periphery of the rotor, and two flux barriers. Herein, the first end of each flux barrier is positioned at a second angle (θ2) from the second end of each magnet in the first set, and the second end of each flux barrier is positioned adjacent to the outer periphery of the rotor. Furthermore, the first end of each flux barrier is positioned at a fourth angle (θ4) from each end of the second set of one magnet, and the second end of each flux barrier is positioned adjacent to the outer periphery of the rotor.

[0015] In another embodiment of the present invention, the first angle (θ1) is greater than the second angle (θ2), and the third angle (θ3) is greater than the fourth angle (θ4).

[0016] In another embodiment of the invention, each of the recesses is adjacent to the second end of each flux barrier.

[0017] In another embodiment of the present invention, a first set of two magnets and a second set of magnets are configured together in a V-shape to form a triangular shape.

[0018] In another embodiment of the present invention, the number of magnetic poles is six, and the number of slots for winding is thirty-six.

Implementation Method

[0020] This invention relates to a rotary electric motor. Specifically, this invention relates to a rotary electric motor that reduces harmonics and torque ripple.

[0021] Figure 1 illustrates the rotor 120 of the rotary electric machine 100. As illustrated, in the figure, the rotor 120 has an even number of magnetic poles 122. Each of the magnetic poles 122 has a substantially similar external geometry. In the embodiment illustrated in Figure 1, the rotor has six poles 122A, 122B, 122C, 122D, 122E, and 122F. The rotor 120 of the rotary electric machine 100 is rotatably engaged with the stator 110 (as shown in Figure 2). The stator 110 of the rotary electric machine 100 has a plurality of slots 112 for winding coils (as shown in Figure 2). In an embodiment of the invention, the slots 112 of the stator 110 accommodate three pairs of coil windings (not shown), each pair being uniformly offset from each other by an angle and distributed equally along the stator 110 depending on the positioning of the slots 112. In an embodiment of the invention, the rotary motor 100 has thirty-six slots 112, wherein each slot 112 is offset from each other by an angle of 10 degrees.

[0022] As illustrated in FIG. 1, each of the magnetic poles 122 includes at least three magnets. Hereinafter, a first set 124 of at least two magnets 124A, 124B is configured in a substantially V-shaped configuration, and a second set 128 of at least one magnet 128A is disposed between the first set 124 of magnets and the outer periphery 132 of rotor 120. As further illustrated in FIG. 1, at least one flux barrier 126 is located between the first set 124 of magnets and the outer periphery 132 of rotor 120, and at least one flux barrier 130 is located between the second set 128 of magnets and the outer periphery 132 of rotor 120. As can be seen in FIG. 1, in an embodiment of the present invention, the first set 124 of the two magnets 124A, 124B (shown in FIG. 3) configured in a V-shape, together with the second set 128 of one magnet 128A, forms a triangular configuration. The voltage obtained in the delta configuration of the present invention is lower than the voltage in the star configuration of a conventional rotor design. However, the voltage increase in the delta configuration is achieved by increasing the number of rotations in the windings on the slots 112 of the stator 110. The increase in the number of rotations in the windings on the stator 110 is preferably higher than the higher strands in the star configuration used to obtain a sinusoidal voltage waveform.

[0023] FIG3 illustrates a portion of the rotor 120 of a rotary electric motor 100 according to an embodiment of the present invention, depicting two adjacent poles 122A, 122B in the rotor 120. Each magnet in a first set 124 of two magnets 124A, 124B has a first end 124A', 124B' (shown in FIG4 and 5) and a second end 124A'', 124B'' (shown in FIG4 and 5). Hereinafter, the first ends 124A', 124B' of each of the magnets in the first set 124 are adjacent to each other. In an embodiment of the present invention, the first ends 124A', 124B' of each magnet in the first set 124 are adjacent to each other with a gap between them.

[0024] Figure 4 illustrates the illustrative odd-numbered (n={2K+1,K≥0}) pole 122A of rotor 120. As illustrated in Figure 4 and mentioned in Figure 3, among the poles numbered (n={2K+1,K≥0}) 122A, 122C, 122E, i.e., the poles numbered 1, 3, 5, etc., the first set 124 of two magnets 124A and 124B is symmetrically arranged in a substantially V-shaped configuration along the central axis A-A' of the odd-numbered pole 122A, and the second set 128 of a magnet 128A is arranged between the first set 124 and the outer periphery 132 of rotor 120. Odd-numbered poles 122A, 122C, 122E (shown in Figure 1) further have two flux barriers 126, wherein the first ends 126A', 126B' of each of flux barriers 126A, 126B are positioned at a first angle θ1 with the second ends 124A'', 124B'' of each of the first sets 124, and the second ends 126A'', 126B'' of each of flux barriers 126A, 126B are positioned adjacent to the outer periphery 132 of the rotor 120. In an embodiment, the first ends 126A', 126B' of flux barriers 126A, 126B are curved to align with the magnets 124A, 124B of the first set 124 to which they are attached.

[0025] Odd-numbered poles 122A, 122C, 122E, etc., further have two flux barriers 130A and 130B, wherein the first end 130A' and 130B' of each of the flux barriers 130A and 130B are positioned at a third angle θ3 with each end 128A' and 128A'' of the second set 128 of a magnet 128A, and the second end 130A'' and 130B'' of each of the flux barriers 130A and 130B are positioned adjacent to the outer periphery 132 of the rotor 120.

[0026] Figure 5 illustrates the exemplary even-numbered (n={2K,K≥1}) pole 122B of rotor 120. As illustrated in Figures 3 and 5, in the poles numbered n={2K,K≥1} 122B, 122D, 122F, that is, the poles numbered 2, 4, 6, etc., the first set 124 of two magnets 124A and 124B is arranged symmetrically in a substantially V-shaped configuration along the central axis B-B' of the even-numbered pole 122B, and the second set 128 of a magnet 128A is arranged between the first set 124 and the outer periphery 132 of rotor 120. Even-numbered poles 122B, 122D, 122F, etc., further have two flux barriers 126A and 126B, wherein the first end 126A', 126B' of each of the flux barriers 126A and 126B is positioned at a second angle θ2 with the second end 124A'', 124B'' of each of the magnets 124A and 124B of the first set 124, and the second end 126A'', 126B'' of each of the flux barriers 126A and 126B is positioned adjacent to the outer periphery 132 of the rotor 120. The first end 126A', 126B' of the flux barriers 126A and 126B is curved, thereby aligning with the magnets 124A and 124B of the first set 124 to which they are attached.

[0027] The even-numbered poles 122B, 122D, 122F, etc., further have two flux barriers 130A and 130B, wherein the first end 130A' and 130B' of each of the flux barriers 130A and 130B are positioned at a fourth angle θ4 with each end 128A' and 128A'' of the second set 128 of the first magnet 128A, and the second end 130A'' and 130B'' of each of the flux barriers 130A and 130B are positioned adjacent to the outer periphery 132 of the rotor 120.

[0028] In an embodiment of the present invention, as mentioned in Figures 3, 4, and 5, the first angle θ1 is greater than the second angle θ2. That is, the angle between the first end 126A'126B' of each of the flux barriers 126A and 126B formed in the odd-numbered poles 122A, 122B, and 122E and the second end 124A''124B'' of each of the magnets 124A and 124B in the first set 124 is greater than the angle between the first end 126A'126B' of each of the flux barriers 126A and 126B formed in the even-numbered poles 122B, 122D, and 122F and the second end 124A and 124B of each of the magnets 124A and 124B in the first set 124. Furthermore, the third angle θ3 is greater than the fourth angle θ4, that is, the angle between the first ends 130A', 130B' of each of the flux barriers 130A, 130B formed in the odd-numbered poles 122A, 122C, 122E and the first ends 128A', 128A'' of each of the second set 128 of a magnet 128A is greater than the angle between the first ends 130A', 130B' of each of the flux barriers 130A, 130B formed in the even-numbered poles 122B, 122D, 122F and the first ends 128A', 128A'' of each of the second set 128 of a magnet 128A.

[0029] This alternating arrangement of magnets 124, 128 and flux barriers 126, 130 in the adjacent odd and even numbered poles 122 of rotor 120 improves the magnetic reluctance difference between rotor 120 and stator 110 surrounding the outer perimeter 132 of rotor 120, reducing its significance and thus improving the long-term use of magnets during operation. Furthermore, the alternating arrangement of magnets 124, 128 and flux barriers 126, 130 in the adjacent poles 122 of rotor 120 reduces distortion in the back electromotive force waveform, ultimately reducing harmonics in the waveform and generating a more sinusoidal voltage waveform and reducing torque ripple.

[0030] Furthermore, the magnets 124, 128 and flux barriers 126, 130 in the poles 122 of the rotor 120 are configured such that the flux barriers 126, 130 have curved profiles at their respective first ends 126A', 126B', 130A', 130B' and all flux barriers 126, 130 have curved edges at their first ends 126A', 126B', 130A', 130B' and second ends 126A'', 126B'', 130A'', 130B'' instead of conventional sharp edges, thereby reducing the chance of flux concentration at sharp edges and thus reducing the possibility of core saturation.

[0031] As further illustrated in Figure 3, similar magnets have crossed odd and even numbering poles 122 for a first set 124 of two magnets 124A and 124B and a second set 128 of one magnet 128A, thus eliminating the need to manufacture magnets separately for the first set 124 and the second set 128.

[0032] As illustrated in Figures 6 and 7, the rotor 120 has a plurality of recesses 134 on its outer periphery 132, thereby creating a non-uniform outer periphery 132 of the rotor 120. This non-uniform outer periphery 132 creates a non-uniform air gap between the rotor 120 and the stator 110. This non-uniform air gap causes the air gap MMF distribution to approach a sinusoidal shape, thus further enhancing the sinusoidal back EMF waveform. In an embodiment of the invention, each of the recesses 134 is adjacent to the second end 126A'', 126B'', 130A'', 130B'' of each flux barrier 126A, 126B, 130A, 130B. In an embodiment of the present invention, each pole 122 has four recesses corresponding to the second ends 126A'', 126B'' of the two flux barriers 126A, 126B of the first set 124 which combines two magnets 124A, 124B, and the second ends 130A'', 130B'' of the two flux barriers 130A, 130B'' of the second end 128A of a magnet 128A.

[0033] Advantageously, the configuration of the magnets and flux barriers at the rotor poles induces a near-sinusoidal back electromotive force curve, reducing harmonics and resulting heat generation, thus allowing delta connection for the stator windings. The advantage of using delta connection in the windings is higher reliability. If one of the three primary windings fails, the secondary will still generate full voltage across all three stages. The only requirement is that the remaining two stages must be able to carry the load.

[0034] Furthermore, the cogging torque in this invention decreases as its significance decreases, thereby reducing torque ripple and contributing to a more sinusoidal back electromotive force waveform.

[0035] Furthermore, since similar magnets are used for the first and second sets of poles, the requirement to manufacture individual permanent magnets is eliminated, thereby reducing manufacturing and assembly costs. In addition, the use of similar magnets in the rotor results in rotational symmetry of the rotor laminates, which simplifies the rotor stacking process. For example, in the case of asymmetric laminate geometry, the laminates can be stacked in only one method.

[0036] Although the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined by the following claims. [Simplified Explanation of the Diagram]

[0019] Examples of embodiments of the present invention will be illustrated in the accompanying drawings with reference to the embodiments of the invention. These drawings are intended to be illustrative and not restrictive. Although the invention is generally described in the context of these embodiments, it should be understood that the scope of the invention is not intended to be limited to these specific embodiments. [Figure 1] Illustrate the rotor of a rotary electric machine according to an embodiment of the present invention. [Figure 2] Illustrate a rotary electric machine having a stator according to an embodiment of the present invention. [Figure 3] Illustrate the adjacent poles of the rotor of a rotary electric machine according to an embodiment of the present invention. [Figure 4] Illustrate the exemplary odd-numbered poles of the rotor of a rotary electric machine according to an embodiment of the present invention. [Figure 5] Illustrate the exemplary even-numbered poles of the rotor of a rotary electric machine according to an embodiment of the present invention. [Figure 6] and [Figure 7] Illustrate a plurality of recesses of the rotor according to an embodiment of the present invention.

Claims

1. A rotary electric motor (100), comprising: A stator (110) having a plurality of slots (112) for winding; and a rotor (120) having an even number of magnetic poles (122) and rotatably engaging with the stator (110), each of the magnetic poles (122) comprising: at least three magnets, wherein a first set (124) of at least two of the at least three magnets is configured in a substantially V-shaped configuration and a second set (124) of at least three magnets comprises: 28) disposed between the first set (124) of the magnet and one of the outer peripheries (132) of the rotor (120); flux barrier, at least one of the flux barriers (126) being located between the first set (124) of the magnet and the outer periphery (132) of the rotor (120), and at least one of the flux barriers (130) being located between the second set (128) of the magnet and the outer periphery (132) of the rotor (120).

2. The rotary motor (100) of claim 1 includes a plurality of recesses (134) on the outer periphery (132) of the rotor (120).

3. The rotary motor (100) of claim 1, wherein each of the two magnets (124A, 124B) in the first set (124) comprises: A first end (124A', 124B') and a second end (124A'', 124B''), wherein the first end (124A', 124B') of each of the magnets (124A, 124B) in the first set (124) is adjacent to each other.

4. The rotary motor (100) of claim 3, wherein the first ends (124A', 124B') of each of the magnets (124A, 124B) in the first set (124) are adjacent to each other with a gap between them.

5. The rotary motor (100) of claim 3, wherein the magnetic pole (122) numbered n={2K+1,K≥0} includes a first set (124) of two magnets (124A, 124B) arranged in a substantially V-shaped configuration symmetrically along a central axis (A-A') of the magnetic pole (122), and a second set (128) of one magnet (128A) arranged between the first set (124) and the outer periphery (132) of the rotor (120).

6. The rotary motor (100) of claim 3, wherein a first end (126A', 126B') of each of two of the flux barriers (126A, 126B) is positioned at a first angle (θ1) with the second end (124A'', 124B'') of each of the magnets (124A, 124B) in the first set (124), and a second end (126A'', 126B'') of each of two of the flux barriers (126, 126B) is positioned adjacent to the outer periphery (132) of the rotor (120).

7. The rotary motor (100) of claim 1, wherein a first end (130A', 130B') of each of two of the flux barriers (130A, 130B) is positioned at a third angle (θ3) with each end (128A', 128A'') of the second set (128) of a magnet (128A), and a second end (130A'', 130B'') of each of the two flux barriers (130A, 130B) is positioned adjacent to the outer periphery (132) of the rotor (120).

8. The rotating electric motor (100) of claim 1, wherein the magnetic pole (122) numbered n={2K,K≥1} includes a first set (124) of two magnets (124A, 124B) arranged in a substantially V-shaped configuration symmetrically along a central axis (B-B') of the magnetic pole (122), and a second set (128) of one magnet (128A) arranged between the first set (124) and the outer periphery (132) of the rotor (120).

9. The rotary motor (100) of claim 6, wherein the first end (126A', 126B') of each of two of the flux barriers (126A, 126B) is positioned at a second angle (θ2) with the second end (124A'', 124B'') of each of the magnets (124A, 124B) in the first set (124), and the second end (126A'', 126B'') of each of the two of the flux barriers (126, 126B) is positioned adjacent to the outer periphery (132) of the rotor (120), wherein the first angle (θ1) is greater than the second angle (θ2).

10. The rotary motor (100) of claim 7, wherein the first end (130A', 130B') of each of two of the flux barriers (130A, 130B) is positioned at a fourth angle (θ4) with each end (128A', 128A'') of the second set (128) of a magnet (128A), and the second end (130A'', 130B'') of each of the two flux barriers (130A, 130B) is positioned adjacent to the outer periphery (132) of the rotor (120), wherein the third angle (θ3) is greater than the fourth angle (θ4).

11. The rotary motor (100) of any of claims 2, 6, 7, 9 and 10, wherein each of the recesses (134) is adjacent to the second end (126A'', 126B'', 130A'', 130B'') of each of the flux barriers (126A, 126B, 130A, 130B).

12. The rotary motor (100) of claim 5 or 8, wherein the first set (124) of the two magnets (124A, 124B) configured in a V-shape and the second set (128) of the magnet (128A) together form a triangular shape.

13. The rotary motor (100) of claim 1, wherein the number of magnetic poles (122) is six.

14. The rotary motor (100) of claim 1, wherein the number of slots (112) for the winding is thirty-six.

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