Rotor and rotating electric machine

Abstract

A rotor (10) of a rotating electric machine is provided with: a shaft (11); a plurality of permanent magnets (12) provided to the outer circumference of the shaft (11) and disposed so as to be away from one another in the circumferential direction; and a rotor coil part (13) that is provided to the outer circumference of the permanent magnets (12), covers the plurality of permanent magnets (12), and has a plurality of rotor coils (3) each including two linear conductors (3a) that are disposed in the axial direction so as to be away from each other in the circumferential direction, and a connection conductor (3b) connecting between the linear conductors (3a). At least one of the two linear conductors (3a) is disposed radially outward of the permanent magnets (12). The rotor coil pitch (τ) is smaller than the pole pitch (W1).

Description

Technical Field

[0001] The present disclosure relates to a rotor of a rotating electric machine in which permanent magnets are provided on the outer peripheral portion of a rotor core, and to a rotating electric machine.

Background Art

[0002] Generally, in a rotating electric machine for high-speed rotation, when PWM (Pulse Width Modulation) control using an inverter is performed, harmonic fluxes of the carrier frequency component are generated, so eddy currents are generated in the rotor core and permanent magnets in the rotor, and the rotor generates heat. When the rotor generates heat, the temperature of the permanent magnet rises and demagnetization of the permanent magnet occurs.

[0003] In order to suppress heat generation in such a rotor, a rotor of a rotating electric machine in which a rotor core and a permanent magnet are surrounded by a highly conductive member having a higher conductivity than the rotor core and the permanent magnet has been proposed (for example, Patent Document 1). In such a rotor of a rotating electric machine, by causing the harmonic flux of the carrier frequency component generated in the stator to intersect with the highly conductive member, the harmonic flux reaching the permanent magnet is reduced, and demagnetization of the permanent magnet is suppressed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in Patent Document 1, while it is effective in suppressing eddy current losses (hereinafter abbreviated as carrier harmonic losses) caused by harmonics of the carrier frequency component, there is a problem that eddy current losses (hereinafter abbreviated as slot harmonic losses) caused by slot harmonics generated by the change in permeance at the slot opening of the stator occur in the highly conductive member.

[0006] Slot harmonic losses decrease as the gap between the stator and rotor increases. In high-speed rotating electric machines, the gap between the stator and rotor is set to be large, so slot harmonic losses are small compared to carrier harmonic losses. However, in order to achieve even higher speeds, it is necessary to further reduce the number of turns in the stator winding, which reduces the motor inductance and increases carrier harmonic losses. To reduce this, it is necessary to increase the thickness of the highly conductive material, but increasing the thickness reduces the gap, which increases the slot harmonic losses in the highly conductive material. Thus, in the configuration of Patent Document 1, which provides a highly conductive material, it was difficult to reduce both carrier harmonic losses and slot harmonic losses.

[0007] This disclosure is made in view of the above, and aims to provide a rotor for a rotating electric machine that can suppress carrier harmonic loss and slot harmonic loss and suppress demagnetization of permanent magnets. [Means for solving the problem]

[0008] To solve the above-mentioned problems and achieve the objective, the rotor of the rotating electric machine in this disclosure comprises a shaft, a plurality of permanent magnets provided on the outer circumference of the shaft and spaced apart from each other in the circumferential direction, a plurality of rotor coils each containing a plurality of rotor coils, each containing a plurality of permanent magnets, a plurality of permanent magnets, a plurality of straight conductors provided on the outer circumference of the permanent magnets and spaced apart in the circumferential direction and spaced apart in the axial direction, and a connecting conductor connecting the straight conductors, wherein at least one of the two straight conductors constituting the rotor coil is positioned radially outward from the permanent magnet. The rotor coil pitch, which is the circumferential angle between the two straight conductors of the coil constituting the rotor coil, is smaller than the pole pitch, which is the angle between adjacent permanent magnets. [Effects of the Invention]

[0009] The rotor of the rotating electric machine according to this disclosure has the effect of suppressing carrier harmonic losses and slot harmonic losses, and suppressing demagnetization of the permanent magnet. [Brief explanation of the drawing]

[0010] [Figure 1] Cross-sectional view showing the configuration of the rotating electric machine according to Embodiment 1 [Figure 2] Cross-sectional view showing the configuration of the rotating electric machine according to Embodiment 1 [Figure 3] Developed view of the rotor of the rotating electric machine according to Embodiment 1, shown in a linear arrangement. [Figure 4] This diagram shows how carrier harmonic fluxes link with the rotor of the comparative example. [Figure 5] This figure shows how carrier harmonic magnetic flux links with the rotor of Embodiment 1. [Figure 6] In Embodiment 1, the graph shows the relationship between the rotor coil pitch and the amount of magnetic flux due to slot harmonic flux. [Figure 7] Developed view of the rotor of the rotating electric machine according to Embodiment 2, shown in a linear arrangement. [Figure 8] In Embodiment 2, a graph showing the relationship between the adjacent coil pitch and the amount of magnetic flux due to slot harmonic flux. [Figure 9] Developed view of the rotor of the rotating electric machine according to Embodiment 3, shown in a linear arrangement. [Figure 10] In Embodiment 3, a graph showing the relationship between the coil skew angle and the amount of magnetic flux due to slot harmonic flux. [Modes for carrying out the invention]

[0011] The rotor and rotating electric machine according to the embodiment will be described in detail below with reference to the drawings.

[0012] Embodiment 1. Figure 1 is a cross-sectional view showing the configuration of the rotating electric machine 1 according to Embodiment 1. Figure 2 is a cross-sectional view showing the configuration of the rotating electric machine 1 according to Embodiment 1. Figure 2 is a cross-sectional view along the line II-II in Figure 1. In Figures 1 and 2, the rotating electric machine 1 has a rotor 10 and a stator 20. The stator 20 has a cylindrical shape that surrounds the rotor 10 with a gap 5. The rotor 10 and the stator 20 have a common axis A and are arranged coaxially. Also, in this example, as shown in Figure 2, the configurations of the rotor 10 and the stator 20 are symmetrical with respect to a perpendicular line B that is perpendicular to axis A at the center position of the stator 20 in the direction of axis A. Hereafter, the direction of axis A will be referred to as the axial direction, the direction of perpendicular line B will be referred to as the radial direction, and the direction perpendicular to the perpendicular line B with axis A as the center will be referred to as the circumferential direction.

[0013] The stator 20 has a cylindrical stator core 21 made of magnetic material and stator coils 25 provided on the stator core 21. The stator core 21 has a cylindrical back yoke 22 and a plurality of teeth 23 that protrude radially inward from the inner circumference of the back yoke 22. Each tooth 23 is spaced apart from each other in the circumferential direction of the rotating electric machine 1. Between each tooth 23, a slot 24 is formed, which is a space that is open radially inward of the stator 20. The stator coils 25 are wound around each tooth 23 and placed in each slot 24. In addition, as shown in Figure 2, the stator coils 25 have coil ends 25a that protrude from the stator core 21 in the direction along the axial direction. Current is supplied to the stator coils 25 by PWM control using an inverter (not shown). A rotating magnetic field is generated in the stator 20 by the supply of power to the stator coils 25.

[0014] The rotor 10 is rotatable about axis A. The rotor 10 also includes a shaft 11 as the rotor core, a plurality of permanent magnets 12 provided on the outer circumference of the shaft 11, a cylindrical rotor coil section 13 that surrounds the shaft 11 and the plurality of permanent magnets 12 together, and a sheet-like holding member 14 that surrounds the shaft 11, the plurality of permanent magnets 12 and the rotor coil section 13 together.

[0015] The shaft 11 is a cylindrical member having the axis A as its central axis. Further, the shaft 11 is made of a magnetic material.

[0016] The plurality of permanent magnets 12 are arranged at intervals in the circumferential direction of the rotor 10. In this example, four permanent magnets 12 are arranged at equal intervals in the circumferential direction of the rotor 10. Each permanent magnet 12 is a segment magnet having an arc-shaped cross section along the outer peripheral surface of the shaft 11. The angle formed by the pole center portions, which are the center points of the permanent magnets 12 adjacent to each other in the circumferential direction, is called the pole pitch W1. When the total number of the permanent magnets 12 is four, the pole pitch W1 (see FIG. 3) is 90 degrees. Also, a magnet-intermediate region 15 exists between the permanent magnets 12 adjacent to each other in the circumferential direction. The magnet-intermediate region 15 may be, for example, air, or an inter-pole member such as a resin material or an iron-based material may be provided. As the permanent magnet 12, for example, a rare-earth magnet or a ferrite magnet is used.

[0017] FIG. 3 is a developed view in which the rotor 10 of the rotating electric machine 1 according to Embodiment 1 is developed linearly. In FIG. 3, the rotor coil portion 13, the permanent magnet 12, and the shaft 11 of the rotor 10 are extracted. The rotor coil portion 13 is provided on the outer peripheral side of the permanent magnet 12 and is composed of a plurality of rotor coils 3. Each rotor coil 3 is composed of two straight conductors 3a arranged apart in the circumferential direction and extending in the axial direction, and a connection conductor 3b connecting between the straight conductors 3a, and forms a closed loop. The circumferential angle centered on the axis A between the two straight conductors 3a that constitute the rotor coil 3 and extend in the axial direction is called the rotor coil pitch τ.

[0018] In Embodiment 1, the rotor coil pitch τ is smaller than the aforementioned pole pitch W1. Also, at least one of the two straight conductors 3a that extend in the axial direction of each rotor coil 3 faces the outside of the permanent magnet 12 and is located radially outside the permanent magnet 12. The operation and effect of such a configuration will be described later.

[0019] Examples of materials that make up the rotor coil 3 include copper or aluminum. The rotor coil section 13 is integrally molded from, for example, a single bendable printed circuit board, and the rotor coil section 13 is an integral unit without being separated. However, as long as the rotor coil section 13 is an integral unit, it may be made of a material other than a printed circuit board.

[0020] The retaining member 14 overlaps the outer circumferential surface of the rotor coil section 13, covering the shaft 11, the multiple permanent magnets 12, and the rotor coil section 13 around the entire circumference of the rotor 10. This reinforces the rotor 10 and prevents the permanent magnets 12 from being scattered from the shaft 11 by centrifugal force when the rotor 10 rotates at high speed. The retaining member 14 is made of a non-magnetic, non-conductive material. Examples of materials used to make up the retaining member 14 include carbon fiber reinforced plastics (CFRP) and glass fiber reinforced plastics (GFRP).

[0021] Next, the procedure for assembling the rotor 10 will be described. After attaching multiple permanent magnets 12 to the outer circumference of the shaft 11, a cylindrical rotor coil section 13 is inserted around the shaft 11 and the outer circumference of the multiple permanent magnets 12. This covers the outer circumference of the multiple permanent magnets 12 with the rotor coil section 13. After this, a sheet-like retaining member 14 is wound around the shaft 11, the multiple permanent magnets 12, and the rotor coil section 13 from the radially outer side. This covers the outer circumference of the rotor coil section 13 with the retaining member 14, completing the rotor 10.

[0022] Next, the operation will be described. When current is supplied to the stator coil 25 from the inverter via PWM control, a rotating magnetic field is generated in the stator 20. When a rotating magnetic field is generated in the stator 20, the rotor 10 rotates around axis A. The current supplied to the stator coil 25 via PWM control contains carrier harmonic components due to the carrier frequency. When a current containing carrier harmonic components is supplied to the stator coil 25, in addition to the fundamental wave magnetic flux that contributes to torque, carrier harmonic magnetic flux due to the carrier harmonic components is also generated in the stator 20. Furthermore, the magnetic flux created by the stator coil 25 passes through the back yoke 22 and teeth 23 and links with the rotor 10. The inner diameter surface of the stator 20 has teeth 23 with high permeance and slots 24 with low permeance arranged intermittently, and when the rotor 10 rotates, the harmonic magnetic flux generated by the spatial fluctuation of permeance links with the rotor 10.

[0023] Next, the mechanism for suppressing carrier harmonic loss will be explained in comparison with the comparative example. Figure 4 shows how carrier harmonic flux links with the rotor 10 of the comparative example. In Figure 4, eddy currents C flowing from the back of the page to the front are indicated by a symbol with a black circle inside a white circle, and eddy currents C flowing from the front of the page to the back are indicated by a symbol with an × inside a white circle. Carrier harmonic flux is the harmonic flux of the carrier frequency component. In the comparative example, the straight conductors 3a of the rotor coil 3 of the rotor coil section 13 are arranged only in the intermagnet region 15 near the outer edge of each magnetic pole of the permanent magnet 12, and the straight conductors 3a of the rotor coil 3 of the rotor coil section 13 are not arranged radially outward from the permanent magnet 12.

[0024] The carrier harmonic flux P1 is a high-frequency carrier flux generated in the stator 20 and flowing into the rotor 10 from the pole center of the permanent magnet 12. When this carrier harmonic flux P1 links with the rotor coil section 13, eddy currents C are generated in the rotor coil section 13. When eddy currents C are generated in the rotor coil section 13, a magnetic flux P2 is generated due to the eddy currents C. The magnetic flux P2 due to the eddy currents C is generated in a direction that cancels out the carrier harmonic flux P1. As a result, the carrier harmonic flux P1 that links with the shaft 11 and the permanent magnet 12 is reduced, and the heat generated in the shaft 11 and the permanent magnet 12 is reduced. The rotor coil section 13 is heated due to the generation of eddy currents C, but because the conductivity of the rotor coil section 13 is higher than that of the permanent magnet 12, the heat generated in the rotor coil section 13 is smaller than the heat generated in the permanent magnet 12 when the carrier harmonic flux P1 links with the permanent magnet 12. This suppresses the overall heat generation of the rotor 10.

[0025] The carrier harmonic flux P3 is generated in the stator 20 and flows into the rotor 10 from the intermagnet region 15. In order to cancel out this carrier harmonic flux P3, eddy currents C must be generated in the rotor coil 3 located radially outside the permanent magnet 12. In the comparative example, since the straight conductors 3a of the rotor coil 3 of the rotor coil section 13 are located only in the intermagnet region 15, the carrier harmonic flux P3 flowing into the rotor 10 from the intermagnet region 15 cannot be canceled out. As a result, eddy currents C are generated in the interpole members and shaft 11 located in the intermagnet region 15 by the carrier harmonic flux P3, and the effect of reducing carrier harmonic loss is insufficient.

[0026] Figure 5 shows how carrier harmonic flux links with the rotor 10 in Embodiment 1. In Figure 5, eddy currents C flowing from the back to the front of the paper are indicated by a symbol with a black circle inside a white circle, and eddy currents C flowing from the front to the back of the paper are indicated by a symbol with an "x" inside a white circle. In Embodiment 1, since conductors are arranged not only in the intermagnet region 15 but also radially outside the permanent magnet 12, it has the effect of canceling out not only the carrier harmonic flux P1 flowing into the rotor 10 from the pole center but also the carrier harmonic flux P3 flowing into the rotor 10 from the intermagnet region 15, which is the inter-pole part, and a sufficient carrier harmonic loss reduction effect can be obtained.

[0027] Next, the mechanism for suppressing slot harmonic loss according to Embodiment 1 will be explained in comparison with a comparative example.

[0028] In the comparative example, when the number of poles of the permanent magnet 12 is P, the circumferential angle is θ, the rotational angular velocity is ω, and the time is t, the distribution of the magnetomotive force F due to the permanent magnet 12 is given by equation (1). F0 is the maximum value of the electromotive force F.

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[0029] Next, the permeance P consists of a component that does not change with respect to the circumferential position and a component that changes due to the slots 24 of the stator 20. If the number of slots is N, this is given by equation (2). P0 is the maximum value of the permeance P.

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[0030] The magnetic flux density B in gap 5 is the product of the magnetomotive force F and the permeance P, and is given by equation (3).

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[0031] In equation (3), the first term is the fundamental flux, and the second and third terms are the slot harmonic fluxes. Equation (3) is expressed in the stator coordinate system, and converting it to the rotor coordinate system results in equation (4).

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[0032] The fundamental wave flux in the first term does not vary over time in the rotor coordinate system and therefore does not contribute to eddy current generation. However, the slot harmonics in the second and third terms do vary over time in the rotor coordinate system. As a result, eddy currents flow in the rotor 10 to cancel out these time variations. If a conductive member is provided near the gap 5, very large eddy current losses occur.

[0033] Next, Embodiment 1 will be described. In Embodiment 1, the straight conductor 3a of the rotor coil 3 of the rotor coil section 13 is provided on the outside of the permanent magnet 12. Regarding the amount of magnetic flux linked to each rotor coil 3, the magnetic flux Φ due to the slot harmonic component in the second term of equation (4) is given by equation (5), where L is the axial length of the permanent magnet 12, and its amplitude depends on sin((N+P / 2)τ / 2).

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[0034] Similarly, the magnetic flux Φ due to the slot harmonic component in the third term of equation (4) is given by equation (6), and its amplitude depends on sin((NP / 2)τ / 2).

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[0035] Figure 6 is a graph showing the relationship between the rotor coil pitch τ and the amount of magnetic flux due to slot harmonic flux in Embodiment 1. Figure 6 shows the result of plotting both sin((N+P / 2)τ / 2) and sin((NP / 2)τ / 2) against the rotor coil pitch τ. In Figure 6, the number of poles P is 4 and the number of slots N is 24. Since the pole pitch is 90 degrees (=360 / 4), when the rotor coil pitch τ is the same as the pole pitch, both are 1, and there is no effect in reducing the slot harmonic flux. On the other hand, by making the rotor coil pitch τ smaller than the pole pitch (=90 degrees), both become less than 1. Since eddy current losses occur in the rotor coil 3 in accordance with fluctuations in the amount of magnetic flux linked to the rotor coil 3, by making the rotor coil pitch τ smaller than the pole pitch, the amount of magnetic flux linked to the rotor coil 3 can be reduced, and eddy current losses can be reduced.

[0036] Furthermore, according to equation (5), the rotor coil pitch τ1 at which the flux linkage due to the slot harmonic component in the second term of equation (4) is minimized is given by equation (7).

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[0037] Furthermore, according to equation (6), the rotor coil pitch τ2 at which the flux linkage due to the slot harmonic component in the third term of equation (4) is minimized is given by equation (8).

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[0038] Therefore, by setting the rotor coil pitch τ to τ2 < τ < τ1 as shown in equation (9), the effect of reducing eddy current losses due to slot harmonics can be further obtained.

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[0039] As described above, according to Embodiment 1, at least one of the two straight conductors 3a constituting the rotor coil 3 is positioned radially outward from the permanent magnet 12, and the rotor coil pitch τ is made smaller than the pole pitch W1. This reduces carrier harmonic losses in the permanent magnet 12 and also suppresses slot harmonic losses in the rotor coil 3. As a result, demagnetization of the permanent magnet 12 can be suppressed.

[0040] Embodiment 2. Figure 7 is an exploded view of the rotor 10 of the rotating electric machine 1 according to Embodiment 2, shown in a linear arrangement. In Embodiment 2, the rotor coil section 13 is composed of a plurality of rotor coil groups 13a, 13b, ... Figure 7 shows two rotor coil groups 13a and 13b. Each rotor coil group 13a and 13b is composed of a plurality of rotor coils 3 connected in series. Each rotor coil 3, similar to Embodiment 1, is composed of two straight conductors 3a extending in the axial direction and a connecting conductor 3b connecting the straight conductors 3a.

[0041] In Embodiment 2, similar to Embodiment 1, the rotor coil pitch τ of each rotor coil 3 is smaller than the pole pitch W1. In addition, at least one of the two straight conductors 3a extending in the axial direction of each rotor coil 3 is located radially outward from the permanent magnet 12.

[0042] Furthermore, in Embodiment 2, the circumferential center positions of the straight conductors 3a of each rotor coil 3 constituting a single rotor coil group 13a, 13b are arranged to be different from each other. The circumferential distance between adjacent rotor coils 3 constituting a single rotor coil group 13a, 13b is referred to as the adjacent coil pitch α. In each rotor coil group 13a, 13b, the end of one rotor coil 3 is connected to the beginning of the next rotor coil 3, the end of the next rotor coil 3 is connected to the beginning of the next rotor coil 3, and the end of the next rotor coil 3 is connected to the beginning of the next rotor coil 3. This connection of the end of one rotor coil 3 to the beginning of another rotor coil 3 is called a series connection. That is, the rotor coil groups 13a, 13b in Figure 7 are constructed by connecting multiple rotor coils 3 in series. With this configuration, the magnetic flux due to slot harmonics linked to each rotor coil 3 cancels each other out, and the eddy current loss due to slot harmonic magnetic flux generated in the rotor coil section 13 can be reduced.

[0043] The principle is explained below using mathematical formulas. If the adjacent coil pitch is α, then the total amount of magnetic flux due to the slot harmonic component in the second term of equation (4), which links the three rotor coils 3 of a single rotor coil group 13a, 13b, is Φ. all This is expressed as in equation (10).

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[0044] When equation (10) is calculated, the result is as shown in equation (11).

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[0045] Figure 8 is a graph showing the relationship between the adjacent coil pitch α and the amount of magnetic flux due to slot harmonic flux in Embodiment 2. Figure 8 shows the result of plotting both (1+2cos((N+P / 2)α))) / 3 in equation (11) and (1+2cos((NP / 2)α))) / 3 obtained by similarly calculating the slot harmonic component of the third term of equation (4) against the adjacent coil pitch α. When the adjacent coil pitch α=0, both are 1, and there is no effect in reducing the slot harmonic flux. On the other hand, by making the adjacent coil pitch α larger than 0, both become smaller than 1. Since eddy current losses occur in the rotor coil 3 according to the total amount of magnetic flux linked to the rotor coil groups 13a and 13b of the rotor coil section 13, the eddy current losses generated in the rotor coil section 13 can be reduced by making the adjacent coil pitch α larger than 0.

[0046] In Figure 7, three rotor coils 3 are connected to one rotor coil group 13a, 13b. However, if the rotor coil groups 13a, 13b are composed of two or more rotor coils 3, and the circumferential positions of each rotor coil 3 are different, that is, if the adjacent coil pitch α > 0, the effect of reducing eddy current losses due to slot harmonic magnetic flux generated in the rotor coil section 13 can be similarly obtained.

[0047] As described above, according to Embodiment 2, the rotor coil section 13 includes rotor coil groups 13a and 13b in which a plurality of rotor coils 3 are connected in series, and since the circumferential center positions of the plurality of rotor coils 3 constituting the rotor coil groups 13a and 13b are different from each other, the eddy current loss generated in the rotor coil section 13 can be further reduced.

[0048] Embodiment 3. Figure 9 is an unfolded view of the rotor 10 of the rotating electric machine 1 according to Embodiment 3, shown in a linear shape. The rotor coil section 13 of Embodiment 3 is provided on the outer circumference of the permanent magnet 12 and is composed of a plurality of rotor coils 3. In Figure 9, one of the rotor coils 3 of the rotor coil section 13 is shown extracted. Each rotor coil 3 is composed of two straight conductors 3a extending in the axial direction and a connecting conductor 3b connecting the straight conductors 3a.

[0049] In Embodiment 3, similar to Embodiment 1, the rotor coil pitch τ of each rotor coil 3 is smaller than the pole pitch W1. In addition, at least one of the two straight conductors 3a extending in the axial direction of each rotor coil 3 is located radially outward from the permanent magnet 12.

[0050] Furthermore, in Embodiment 3, the two straight conductors 3a are arranged at an inclination in the circumferential direction rather than parallel to the axial direction. Here, the angle of the straight conductors 3a with respect to the axial direction is called the coil skew angle β. By making the coil skew angle β greater than 0 degrees, the magnetic flux due to slot harmonics linked to the rotor coil 3 can be reduced, and the eddy current loss due to slot harmonic magnetic flux generated in the rotor coil section 13 can be reduced.

[0051] The principle will be explained below using mathematical formulas. The magnetic flux Φ due to the slot harmonic component in the second term of equation (4) is given by equation (12).

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[0052] Figure 10 is a graph showing the relationship between the coil skew angle β and the amount of magnetic flux due to slot harmonic flux in Embodiment 3. Figure 10 shows the result of plotting both sin((N+P / 2)β) / (N+P / 2)β in equation (12) and sin((NP / 2)β) / (NP / 2)β, which is similarly calculated using the slot harmonic component of the third term of equation (4), against the coil skew angle β. When the coil skew angle β = 0, both are 1, and there is no effect in reducing the slot harmonic flux. On the other hand, by making the coil skew angle β larger than 0, both become smaller than 1. Since eddy current losses occur in the rotor coil 3 according to the total amount of magnetic flux linked to the rotor coil 3, the eddy current losses generated in the rotor coil section 13 can be reduced by making the coil skew angle β larger than 0.

[0053] As described above, according to Embodiment 3, the straight conductors 3a constituting the rotor coil 3 are arranged to be inclined in the circumferential direction with respect to the axial direction, which further reduces the eddy current loss generated in the rotor coil section 13.

[0054] The configurations shown in the embodiments described above are merely examples of the content of this disclosure and can be combined with other known technologies, and parts of the configuration can be omitted or modified without departing from the gist of this disclosure. [Explanation of symbols]

[0055] 1 Rotor motor, 3 Rotor coil, 3a Straight conductor, 3b Connecting conductor, 5 Gap, 10 Rotor, 11 Shaft, 12 Permanent magnet, 13 Rotor coil section, 13a, 13b Rotor coil group, 14 Holding member, 15 Intermagnet region, 20 Stator, 21 Stator core, 22 Back yoke, 23 Teeth, 24 Slot, 25 Stator coil, 25a Coil end, W1 Pole pitch, α Adjacent coil pitch, β Coil skew angle, τ,τ1,τ2 Rotor coil pitch.

Claims

1. The shaft and A plurality of permanent magnets are provided on the outer circumference of the shaft and are spaced apart from each other in the circumferential direction, The rotor coil section comprises a plurality of rotor coils, each including two straight conductors provided on the outer circumference of the permanent magnet and arranged axially apart in the circumferential direction, and a connecting conductor connecting the straight conductors, and covering the plurality of permanent magnets. At least one of the two straight conductors constituting the rotor coil is positioned radially outward from the permanent magnet. The rotor coil pitch, which is the circumferential angle between the two straight conductors of the coils constituting the rotor coil, is smaller than the pole pitch, which is the angle between adjacent permanent magnets. A rotor for a rotating electric machine characterized by the following features.

2. The rotor coil section comprises a group of rotor coils in which a plurality of rotor coils are connected in series, and the circumferential center positions of the plurality of rotor coils constituting the rotor coil group are different from each other. The rotor of the rotating electric machine according to feature 1.

3. The straight conductors constituting the rotor coil are arranged to be inclined in the circumferential direction with respect to the axial direction. The rotor of the rotating electric machine according to feature 1.

4. The rotor coil section is formed on a single substrate. The rotor of the rotating electric machine according to feature 1.

5. A rotor of a rotating electric machine according to any one of claims 1 to 4, A stator surrounds the rotor with a gap between them, A rotating electric machine characterized by the following features.

6. When the number of slots in the stator is N, the number of poles is P, and the rotor coil pitch of the two straight conductors of the rotor coil is τ, then τ is given by the following equation [Math 1] satisfies The rotating electric machine according to feature 5.

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