Rotary electric machine

Abstract

To provide a synchronous reluctance motor capable of reducing torque ripple while maintaining torque.SOLUTION: In the synchronous reluctance motor 1, the plurality of flux barriers 10 formed in the rotor core 8 include a first flux barrier disposed on the innermost diameter side of the rotor core 8, a second flux barrier disposed outside the first flux barrier in the radial direction of the rotor core 8, and a third flux barrier disposed outside the second flux barrier in the radial direction of the rotor core 8. The L1, the L2, and the L3 satisfy a relationship of L1 ≥ L2> L3, where L1 is a gap between the outer peripheral surface of the rotator 3 and an end of the first flux barrier, L3 is a gap between the outer peripheral surface of the rotator 3 and an end of the second flux barrier, and is a gap between the outer peripheral surface of the rotator 3 and an end of the third flux barrier. L2.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a rotating electric machine.

Background Art

[0002] As a highly efficient and resource-saving rotating electric machine, a synchronous reluctance motor that does not require windings or permanent magnets on the rotor is known. Generally, a synchronous reluctance motor is configured to include a rotor having a plurality of flux barriers serving as magnetic barriers, and a stator disposed around the rotor via an air gap. Ribs for maintaining the shape of the rotor are disposed between the outer diameter of the rotor and the ends of the flux barriers. With such a structure, the synchronous reluctance motor rotates in synchronization with the rotating magnetic field supplied from the stator by utilizing the magnetic salient pole property of the rotor generated by the flux barriers.

[0003] As prior arts regarding performance improvement of synchronous reluctance motors, for example, Patent Documents 1 and 2 are known. In Patent Document 1, regarding the dimensional relationship of ribs disposed between the ends of the flux barriers and the outer diameter of the rotor as a rotor structure capable of improving motor performance, it is described that "the distances L2 between both circumferential ends of each of the plurality of cavity portions 18 and the outer peripheral portion of the rotor core 9 are set to be substantially the same." Further, in Patent Document 2, regarding the dimensional relationship of ribs disposed between the ends of the flux barriers and the outer diameter of the rotor as a rotor structure capable of improving motor performance while maintaining mechanical strength, it is described that "it is preferable that the relationship of wo1 < wo2 < wo3 holds, but a part or all of them may be the same."

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

[0005] The conventional techniques disclosed in Patent Documents 1 and 2 have had the problem that it is difficult to reduce torque ripple in the low-speed, large-torque region.

[0006] In view of the above-mentioned problems of the conventional technology, an object of the present invention is to provide a synchronous reluctance motor that can reduce torque ripple while maintaining torque. [Means for solving the problem]

[0007] A rotating electric machine according to the present invention comprises a rotor having a rotor core on which a plurality of flux barriers are formed, and a stator arranged on the outer diameter side of the rotor with a predetermined gap therebetween, wherein the plurality of flux barriers each have a generally U-shape that is curved so that their circumferential center is located on the inner diameter side of both ends, and the plurality of flux barriers include a first flux barrier arranged on the innermost diameter side of the rotor core, a second flux barrier arranged radially outward of the rotor core than the first flux barrier, and a third flux barrier arranged radially outward of the rotor core than the second flux barrier, wherein when the distance between the outer peripheral surface of the rotor and an end of the first flux barrier is L1, the distance between the outer peripheral surface of the rotor and the end of the second flux barrier is L2, and the distance between the outer peripheral surface of the rotor and the end of the third flux barrier is L3, L1, L2, and L3 satisfy the relationship L1 ≧ L3 > L2. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a synchronous reluctance motor that can reduce torque ripple while maintaining torque.

[0009] Problems, configurations, and effects other than those described above will become clear from the following description of the embodiments. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing the configuration of a rotating electric machine according to a first embodiment of the present invention. [Figure 2] FIG. 10 is an explanatory diagram of the torque ripple reduction effect due to the thickness of the circumferential rib in the present invention. [Figure 3] FIG. 10 is a diagram showing an example of a torque waveform in a conventional rotor structure. [Figure 4] FIG. 10 is a diagram showing an example of a torque waveform in the rotor structure of the present invention. [Figure 5] FIG. 6 is a diagram showing the configuration of a rotating electric machine according to a second embodiment of the present invention. [Figure 6] FIG. 10 is a diagram showing the magnitude of torque when the distance between each flux barrier and the outer circumferential surface of the rotor is changed in the second embodiment of the present invention. [Figure 7] FIG. 10 is a diagram showing the magnitude of torque ripple when the distance between each flux barrier and the outer circumferential surface of the rotor is changed in the second embodiment of the present invention. [Figure 8] FIG. 10 is a diagram showing the configuration of a rotating electric machine according to a third embodiment of the present invention. [Figure 9] FIG. 10 is a diagram showing the configuration of a rotating electric machine according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and some omissions and simplifications have been made as appropriate for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0012] In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0013] (First embodiment) Fig. 1 is a diagram showing the configuration of a rotating electric machine according to a first embodiment of the present invention. Fig. 1 shows a cross-sectional view of one pole (1 / 6 circumference in this embodiment) of a synchronous reluctance motor 1 having multiple poles, as a diagram showing the configuration of the rotating electric machine of this embodiment. Note that, although explanation will be omitted below, the synchronous reluctance motor 1 of this embodiment has the same structure in parts other than those shown in Fig. 1.

[0014] As shown in FIG. 1, a synchronous reluctance motor 1 includes a stator 2 and a rotor 3. The stator 2 is disposed on the outer diameter side of the rotor 3 with a predetermined gap therebetween. The stator 2 has a stator core 4, and the inner peripheral surface of the stator core 4, i.e., the surface facing the rotor 3, is provided with a plurality of teeth 5 arranged at equal intervals in the circumferential direction. Slots 6 are formed between each of the teeth 5. Armature windings 7 for generating a rotating magnetic field are wound around each of the teeth 5 through these slots 6.

[0015] The rotor 3 includes a rotor core 8 and a shaft 9, and the rotor core 8 and shaft 9 rotate together. The rotor core 8 has a plurality of flux barriers 10 formed on each pole (every sixth of a circumference in this embodiment). Each flux barrier 10 has a curved, approximately U-shaped shape with its circumferential center positioned closer to the inner diameter than both ends, so that the magnetic flux lines in the d-axis direction take the shortest path. In addition, circumferential ribs 11 are provided between the ends of each flux barrier 10 and the outer circumferential surface of the rotor 3.

[0016] In this embodiment, the rotor core 8 is divided into multiple parts in the radial direction by the flux barriers 10, and the individual parts are referred to as rotor cores 8-A, 8-B, and 8-C, starting from the inner diameter side. The flux barrier 10 sandwiched between rotor core 8-A and rotor core 8-B and arranged on the innermost side of rotor core 8 is referred to as the first flux barrier, the flux barrier 10 sandwiched between rotor core 8-B and rotor core 8-C and arranged radially outward of the first flux barrier is referred to as the second flux barrier, and the flux barrier 10 sandwiched between rotor core 8-C and rotor core 8-D and arranged radially outward of the second flux barrier is referred to as the third flux barrier.

[0017] In this embodiment, the distance between the first flux barrier and the outer peripheral surface of the rotor 3, i.e., the width (thickness) of the circumferential ribs 11 at both ends of the first flux barrier, is defined as L1, the distance between the second flux barrier and the outer peripheral surface of the rotor 3, i.e., the width (thickness) of the circumferential ribs 11 at both ends of the second flux barrier, is defined as L2, and the distance between the third flux barrier and the outer peripheral surface of the rotor 3, i.e., the width (thickness) of the circumferential ribs 11 at both ends of the third flux barrier, is defined as L3. In this case, as shown in Fig. 1, the dimensional relationship between L1, L2, and L3 is configured to be L1 ≥ L3 > L2. This enables torque ripple to be reduced.

[0018] The reason why torque ripple can be reduced by satisfying the above dimensional relationship will be explained below with reference to FIGS. 2, 3 and 4.

[0019] FIG. 2 is an explanatory diagram of the torque ripple reduction effect due to the thickness of the circumferential ribs 11 of the present invention. FIG. 2 is an enlarged view of a portion of the rotor core 8 of FIG. 1 , showing the magnetic flux flow when the width of the circumferential ribs 11 of each flux barrier 10 is changed. Here, FIGS. 2(a) and 2(b) show the magnetic flux flow in a conventional rotor structure, and FIG. 2(c) shows the magnetic flux flow in the rotor structure of the first embodiment of the present invention. Specifically, FIG. 2(a) shows the magnetic flux flow when L1 = L2 = L3 as an example of a conventional rotor structure, and FIG. 2(b) shows the magnetic flux flow when L1 > L2 > L3 as another example of a conventional rotor structure. Furthermore, FIG. 2(c) shows the magnetic flux flow when the above-mentioned dimensional relationship L1 ≥ L3 > L2 is satisfied in the rotor structure of this embodiment. Note that the reference symbols 8-A to 8-D and L1 to L3 in Fig. 2 correspond to the rotor cores 8-A to 8-D and the widths (thicknesses) L1 to L3 of the circumferential ribs 11 in Fig. 1. The arrows in Fig. 2 indicate the flow of magnetic flux, and the difference in their thickness indicates the magnitude relationship of the magnetic flux density.

[0020] As shown in FIG. 2(a), for example, when L1 = L2 = L3, the widths of all circumferential ribs 11 are equal from the pole center (q axis) to the pole outer side (d axis). Therefore, leakage flux flows circumferentially along the outer circumferential surface of the rotor 3 from the circumferential rib 11 (width L3) of the third flux barrier, through the circumferential rib 11 (width L2) of the second flux barrier, to the circumferential rib 11 (width L1) of the first flux barrier. Also, as shown in FIG. 2(b), for example, when L1 > L2 > L3, the width of the circumferential rib 11 increases from the pole center (q axis) to the pole outer side (d axis). Therefore, in this case, as in the case of FIG. 2(a), leakage flux flows circumferentially along the outer circumferential surface of the rotor 3 from the circumferential rib 11 (width L3) of the third flux barrier, through the circumferential rib 11 (width L2) of the second flux barrier, to the circumferential rib 11 (width L1) of the first flux barrier.

[0021] On the other hand, in this embodiment, as shown in Fig. 2(c), due to the dimensional relationship L1 ≥ L3 > L2, the width of the circumferential rib 11 narrows midway from the pole center (q-axis) to the pole outer side (d-axis). Therefore, compared to the cases of Fig. 2(a) and Fig. 2(b), leakage flux is less likely to flow in the circumferential direction along the outer circumferential surface of the rotor 3. In other words, while leakage flux tends to flow in the circumferential direction from the pole center (q-axis) to the pole outer side (d-axis) in the structure of the conventional rotor core, the structure of the rotor core 8 of this embodiment can reduce leakage flux in the circumferential direction.

[0022] Fig. 3 shows an example of torque waveforms in a conventional rotor structure. Fig. 3 shows the magnitude of torque generated at each portion of rotor core 8 for each rotation angle in rotor 3 with the conventional structure shown in Figs. 2(a) and (b). Specifically, Fig. 3 shows torque waveform 31, which represents the sum of torques generated at rotor core 8-A and rotor core 8-B, torque waveform 32, which represents the sum of torques generated at rotor core 8-C and rotor core 8-D, and torque waveform 33, which represents the torque generated in rotor 3 as a whole.

[0023] Fig. 4 is a diagram showing an example of torque waveforms in the rotor structure of the present invention. Fig. 4 shows the magnitude of torque generated at each portion of rotor core 8 for each rotation angle in rotor 3 having the structure of this embodiment shown in Fig. 2(c). Specifically, as in Fig. 3, Fig. 4 also shows torque waveform 41 representing the sum of torque generated at rotor core 8-A and rotor core 8-B, torque waveform 42 representing the sum of torque generated at rotor core 8-C and rotor core 8-D, and torque waveform 43 representing the torque generated in rotor 3 as a whole.

[0024] In a rotor 3 of the conventional structure, as described in Fig. 2, leakage flux flows in the circumferential direction along the outer circumferential surface of the rotor 3, from the circumferential rib 11 (width L3) of the third flux barrier, through the circumferential rib 11 (width L2) of the second flux barrier, to the circumferential rib 11 (width L1) of the first flux barrier. Due to the influence of this leakage flux, a difference in amplitude occurs between torque waveform 31 and torque waveform 32, as shown in Fig. 3. As a result, the torque ripple across the entire rotor 3 becomes large, as shown in torque waveform 33.

[0025] On the other hand, in the rotor 3 having the structure of this embodiment, as explained in Fig. 2, leakage magnetic flux is less likely to flow in the circumferential direction along the outer circumferential surface of the rotor 3. As a result, the amplitudes of torque waveform 41 and torque waveform 42 become approximately equal, as shown in Fig. 4. Therefore, for the entire rotor 3, the torque ripple can be made smaller, as shown by torque waveform 43, than by torque waveform 33 in Fig. 3.

[0026] Specifically, in the rotor 3 having the structure of this embodiment, the widths of the circumferential ribs 11 of each flux barrier satisfy the dimensional relationship L1 ≥ L3 > L2. That is, because the width L2 of the circumferential rib 11 of the second flux barrier is the narrowest, leakage magnetic flux is less likely to flow from the circumferential rib 11 of the third flux barrier to the circumferential rib 11 of the first flux barrier. Furthermore, because the width L1 of the circumferential rib 11 of the first flux barrier is larger than the width L2 of the circumferential rib 11 of the second flux barrier, leakage magnetic flux at the circumferential rib 11 of the first flux barrier increases, and the d-axis magnetic flux flowing to the rotor core 8 decreases. As a result, the torque generated in the rotor core 8-B is relatively reduced, and the amplitude of the torque waveform 41 in FIG. 4 is smaller than that of the torque waveform 31 in FIG. 3. Meanwhile, the torque waveform 42 in FIG. 4 does not change significantly compared to the torque waveform 32 in FIG. 3. As a result, the amplitude of torque waveform 41 and the amplitude of torque waveform 42 become approximately equal, and these cancel each other out, reducing fluctuations in torque waveform 43 of the entire rotor, thereby enabling torque ripple to be reduced.

[0027] As described above, in this embodiment, the rotor 3 is structured so that the widths of the circumferential ribs 11 of each flux barrier 10 satisfy the dimensional relationship L1 ≥ L3 > L2, thereby changing the way leakage flux flows compared to conventional rotor structures. This changes the d-axis magnetic flux flowing through the rotor core 8, and makes it possible to balance the torque generated in each of the rotor cores 8-A, 8-B, 8-C, and 8-D separated by the flux barriers 10 across the entire rotor 3. As a result, torque ripple can be reduced.

[0028] (Second embodiment) Fig. 5 is a diagram showing the configuration of a rotating electric machine according to a second embodiment of the present invention. Like Fig. 1, Fig. 5 shows a cross-sectional view of one pole (1 / 6 circumference in this embodiment) of a synchronous reluctance motor 1A having multiple poles, as a diagram showing the configuration of the rotating electric machine of this embodiment. Note that, although explanation will be omitted below, the synchronous reluctance motor 1A of this embodiment has the same structure in parts other than those shown in Fig. 5.

[0029] 1 described in the first embodiment, in that a fourth flux barrier is further formed radially outside the third flux barrier in rotor core 8. Adding the fourth flux barrier increases the inductance difference between the d-axis and q-axis, thereby increasing torque.

[0030] In this embodiment, as in the first embodiment, the distances between the first to third flux barriers and the outer peripheral surface of the rotor 3 are defined as L1 to L3, respectively, and the distance between the fourth flux barrier and the outer peripheral surface of the rotor 3, i.e., the width (thickness) of the circumferential ribs 11 at both ends of the fourth flux barrier, is defined as L4. Note that, as in the first embodiment, this embodiment is also configured so that the dimensional relationship between L1, L2, and L3 satisfies L1≧L3>L2, which enables torque ripple to be reduced.

[0031] Furthermore, in this embodiment, the dimensional relationship between L1 to L4 is configured to be L1≧L3>L2>L4. In this way, by setting the value of L4 to the smallest value, it is possible to suppress an increase in leakage flux even if the number of divisions of rotor core 8 increases due to the addition of the fourth flux barrier.

[0032] The changes in torque and torque ripple due to the dimensional relationship of this embodiment will be described below with reference to FIGS.

[0033] 6 and 7 show the magnitude of torque and torque ripple of synchronous reluctance motor 1A in the second embodiment of the present invention when the values ​​of distances L1 to L3 between each flux barrier and the outer peripheral surface of rotor 3 are changed while maintaining the dimensional relationship L1≧L3>L2. The vertical axis of Fig. 6 represents torque, and the vertical axis of Fig. 7 represents torque ripple, and the horizontal axis of Fig. 6 and Fig. 7 represent the product of L1 / L2, the ratio of L1 to L2, and L3 / L2, the ratio of L3 to L2.

[0034] From Figure 6, it can be seen that the torque of synchronous reluctance motor 1A is maximized when the value of the product (L1 / L2) * (L3 / L2) shown on the horizontal axis is in the range of 2 to 4. Furthermore, from Figure 7, it can be seen that the torque ripple decreases as the value of the product (L1 / L2) * (L3 / L2) shown on the horizontal axis increases. Therefore, it can be seen that by setting the value of the product (L1 / L2) * (L3 / L2) to 2 or more, it is possible to maintain torque and reduce torque ripple at the same time. In other words, by setting the values ​​of L1 to L3 to satisfy the following relational expression (1), it is possible to maintain torque and reduce torque ripple at the same time. (L1*L3) / (L2) 2 ≧2 (1)

[0035] While the above describes the relationship between the values ​​of L1 to L3 and the torque and torque ripple in the synchronous reluctance motor 1A shown in Fig. 5, a similar relationship holds between the values ​​of L1 to L3 and the torque and torque ripple in the synchronous reluctance motor 1 of Fig. 1 described in the first embodiment. Therefore, by satisfying the above relational expression (1), it is possible to maintain torque and reduce torque ripple at the same time. The same applies to the third and fourth embodiments described below.

[0036] (Third embodiment) Fig. 8 is a diagram showing the configuration of a rotating electric machine according to a third embodiment of the present invention. As with Figs. 1 and 5, Fig. 8 shows a cross-sectional view of one pole (1 / 6 circumference in this embodiment) of a synchronous reluctance motor 1B having multiple poles, as a diagram showing the configuration of the rotating electric machine of this embodiment. Note that, although explanation will be omitted below, synchronous reluctance motor 1B of this embodiment has the same structure in parts other than those shown in Fig. 8.

[0037] 5 described in the second embodiment, in that a plurality of radial ribs 12 are further provided within each flux barrier 10 (first to fourth flux barriers). This prevents deformation of the rotor core 8 even when a strong centrifugal force is applied to the rotor core 8.

[0038] (Fourth embodiment) Fig. 9 is a diagram showing the configuration of a rotating electric machine according to a fourth embodiment of the present invention. As with Figs. 1, 5, and 8, Fig. 9 shows a cross-sectional view of one pole (1 / 6 circumference in this embodiment) of a synchronous reluctance motor 1C having multiple poles, as a diagram showing the configuration of the rotating electric machine of this embodiment. Note that, although explanation will be omitted below, the synchronous reluctance motor 1C of this embodiment has the same structure in parts other than those shown in Fig. 9.

[0039] The synchronous reluctance motor 1C of this embodiment differs from the synchronous reluctance motor 1 of FIG. 1 described in the first embodiment in that recesses 13 recessed toward the inner diameter are provided on the outer peripheral surface of the rotor 3 at positions facing both ends of each flux barrier 10 (first to third flux barriers). Even when the recesses 13 are provided by recessing the outer peripheral surface of the rotor 3 in this way, the distances L1 to L3 between the first to third flux barriers and the outer peripheral surface of the rotor 3 (the bottoms of the recesses 13) are set to satisfy the dimensional relationship L1 ≥ L3 > L2, as in the first embodiment. This achieves the same effects as those described in the first embodiment. Note that the recesses 13 may be filled with a non-magnetic material to fill the depressions on the outer peripheral surface of the rotor 3.

[0040] 9 shows an example in which a synchronous reluctance motor 1C of this embodiment is configured by providing recesses 13 at positions facing the ends of the first to third flux barriers in the synchronous reluctance motor 1 of FIG. 1 described in the first embodiment. However, recesses 13 may also be provided at positions facing the ends of the first to fourth flux barriers in the synchronous reluctance motor 1A of FIG. 5 described in the second embodiment or the synchronous reluctance motor 1B of FIG. 8 described in the third embodiment. In this case, as described in the second embodiment, the distances L1 to L4 between the first to fourth flux barriers and the outer peripheral surface of the rotor 3 (the bottoms of the recesses 13) are set to satisfy the dimensional relationship L1 ≥ L3 > L2 > L4, similar to the second embodiment.

[0041] According to the embodiment of the present invention described above, the following advantageous effects are achieved.

[0042] (1) Synchronous reluctance motors 1, 1A, 1B, and 1C, which are rotating electric machines, include a rotor 3 having a rotor core 8 on which multiple flux barriers 10 are formed, and a stator 2 arranged on the outer diameter side of the rotor 3 with a predetermined gap therebetween. Each of the multiple flux barriers 10 has a generally U-shaped curved shape with its circumferential center located closer to the inner diameter than both ends. The multiple flux barriers 10 also include a first flux barrier arranged on the innermost diameter side of the rotor core 8, a second flux barrier arranged further radially outward from the first flux barrier, and a third flux barrier arranged further radially outward from the second flux barrier. In these synchronous reluctance motors 1, 1A, 1B, and 1C, when the distance between the outer peripheral surface of the rotor 3 and the end of the first flux barrier is L1, the distance between the outer peripheral surface of the rotor 3 and the end of the second flux barrier is L2, and the distance between the outer peripheral surface of the rotor 3 and the end of the third flux barrier is L3, L1, L2, and L3 satisfy the relationship L1 ≥ L3 > L2. This makes it possible to provide synchronous reluctance motors 1, 1A, 1B, and 1C that can reduce torque ripple while maintaining torque.

[0043] (2) In the synchronous reluctance motors 1A and 1B, the plurality of flux barriers 10 further includes a fourth flux barrier that is disposed radially outward of the rotor 3 relative to the third flux barrier. This configuration makes it possible to further increase torque while reducing torque ripple.

[0044] (3) In the synchronous reluctance motors 1, 1A, 1B, and 1C, it is preferable that L1, L2, and L3 satisfy the above-mentioned relational expression (1). This makes it possible to maintain torque and reduce torque ripple at the same time.

[0045] (4) In synchronous reluctance motors 1A and 1B, when the distance between the outer circumferential surface of rotor 3 and the end of the fourth flux barrier is L4, it is preferable that L1, L2, L3, and L4 satisfy the relationship L1 ≥ L3 > L2 > L4. This makes it possible to suppress an increase in leakage flux and reduce torque ripple.

[0046] The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0047] Furthermore, the present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the invention. [Explanation of symbols]

[0048] 1, 1A, 1B, 1C... synchronous reluctance motor, 2... stator, 3... rotor, 4... stator core, 5... teeth, 6... slot, 7... armature winding, 8... rotor core, 9... shaft, 10... flux barrier, 11... circumferential rib, 12... radial rib, 13... recess

Claims

1. a rotor having a rotor core on which a plurality of flux barriers are formed; a stator disposed on the outer diameter side of the rotor via a predetermined gap, each of the plurality of flux barriers has a generally U-shaped curved shape such that a circumferential center thereof is located radially inward relative to both end portions; the plurality of flux barriers include a first flux barrier arranged on the innermost diameter side of the rotor core, a second flux barrier arranged radially outward of the rotor core than the first flux barrier, and a third flux barrier arranged radially outward of the rotor core than the second flux barrier, A rotating electric machine in which, when the distance between the outer peripheral surface of the rotor and the end of the first flux barrier is L1, the distance between the outer peripheral surface of the rotor and the end of the second flux barrier is L2, and the distance between the outer peripheral surface of the rotor and the end of the third flux barrier is L3, L1, L2, and L3 satisfy the relationship L1 ≧ L3 > L2.

2. 2. The rotating electric machine according to claim 1, The plurality of flux barriers further include a fourth flux barrier disposed radially outward of the rotor than the third flux barrier.

3. 2. The rotating electric machine according to claim 1, A rotating electric machine in which L1, L2, and L3 satisfy the following relational expressions: (L1*L3) / (L2) ２ ≧2

4. 3. The rotating electric machine according to claim 2, When the distance between the outer peripheral surface of the rotor and the end of the fourth flux barrier is L4, L1, L2, L3 and L4 satisfy the relationship L1≧L3>L2>L4.

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