JP5244290B2 - Rotor structure of rotating electrical machine - Google Patents

Description

  The present invention relates to a rotor structure of a rotating electrical machine that includes a stator and a rotor that is rotatably provided through a stator and a gap and is configured by embedding a permanent magnet in a core.

2. Description of the Related Art Conventionally, a rotating electrical machine having a stator and a rotor that is rotatably provided through a stator and a gap and is configured by embedding a permanent magnet in a core is, for example, an IPM motor (magnet embedded synchronous motor). It is known (for example, see Patent Documents 1 to 4).
Japanese Patent Laid-Open No. 10-146031 JP 2002-209350 A Japanese Patent Laid-Open No. 10-285845 JP 2004-336999 A

  Among the conventional rotating electric machines described above, Patent Document 1, a technique for approximating the waveform of the induced voltage generated by a permanent magnet rotating electric machine to a sine wave, discloses a permanent magnet having a trapezoidal cross section in the figure. is there. Further, Patent Document 2 improves the shape of the core in which the permanent magnet is embedded to increase the magnetic flux density of the air gap, and at the same time, close the gap magnetic flux distribution to a sine wave to increase torque, reduce torque ripple, and reduce stator iron loss. There is an example disclosure. Further, in Patent Documents 3 and 4, a rotating electrical machine having low vibration, low noise, and high efficiency characteristics is obtained by optimizing the arrangement of a plurality of slits provided in the outer peripheral core of the permanent magnet.

  However, all of the above-described conventional techniques have a problem in that an increase in iron loss occurs when the field is weak with a large current as in the iron loss characteristic shown in FIG. It is thought that the iron loss increases at the time of field weakening at such a large current is caused by the magnetomotive force harmonic of the magnet, and if this can be eliminated, the iron loss can be greatly reduced. However, no effective means has been found yet.

  The object of the present invention is to eliminate the above-mentioned problems, eliminate the magnetomotive force harmonics of the magnet, and provide a rotor structure for a rotating electrical machine that does not increase iron loss even during field weakening with a large current. It is something to be offered.

A rotor structure of a rotating electrical machine according to the present invention is a rotor structure of a rotating electrical machine having a stator, and a rotor that is provided rotatably through a stator and a gap and is configured by embedding a permanent magnet in a core. The magnet structure according to each of claims 1 to 4 is provided with slits at positions near both ends of the magnet structure, and the outer periphery of the slit is inclined so as to approach the q-axis side. it is characterized in that it has been.

  In the present invention, in the cross-section, the magnet structure having a notch portion provided corresponding to the shape of the gap surface at both ends facing the outer periphery, and the positions corresponding to the notch portions at both ends of the magnet structure. and a slit provided in an open state on the q-axis side, so that the magnetic flux can circulate to the q-axis side, and higher-order components (3, 5, 7, 9 in the stator teeth by the magnetic flux). Next, the iron loss generated in the stator can be reduced without reducing torque. As a result, the magnetomotive force harmonics of the magnet can be eliminated, and a rotor structure of a rotating electrical machine with little or no increase in iron loss can be obtained even when the field is weakened with a large current.

  As a preferred example of the present invention, the magnet structure includes a rectangular magnet part having a rectangular parallelepiped cross section, and a trapezoidal magnet part having a cross section integrally provided on the outer periphery of the rectangular magnet part and projecting outward. , Is composed of. With this configuration, the iron loss is reduced and the magnet is arranged near the surface, so that the magnetic flux of the magnet is increased, and further, the d-axis inductance is reduced and the output is increased. Further, the corners of the press are reduced, and the cost can be reduced.

  Further, as a preferred example of the present invention, the magnet structure has a rectangular magnet section having a rectangular parallelepiped section, and a trapezoidal magnet section having a section convex toward the outside integrally provided on the outer periphery of the rectangular magnet section. And a barrier provided at both ends of the trapezoidal magnet portion. By configuring in this way, in addition to the effects described above, the barrier weakens the reverse magnetic field of the current, so that the demagnetization resistance performance of the magnet is improved.

  Furthermore, as a preferred example of the present invention, the magnet structure may include a rectangular magnet part having a rectangular parallelepiped cross section and barriers provided at both ends of the rectangular magnet part. By comprising in this way, in addition to the effect mentioned above, cost reduction can be achieved.

  Furthermore, as a preferable example of the present invention, the magnet structure may be composed of a magnet having a cross-sectional cross section and a larger curvature (= 1 / R) at both ends than at the center. With this configuration, the magnet is arranged closer to the rotor surface as in the above-described example, so that the magnetic flux of the magnet is improved and the torque / output is improved.

  Moreover, as a suitable example of this invention, there exists forming a slit toward an inner periphery from the opening part provided in the outer peripheral gap surface. By configuring in this way, in addition to the effects described above, the centrifugal force applied to the rotor surface is applied to the oblique portion, so that local stress due to bending is relieved, the anti-centrifugal properties are improved, and rotation is performed up to high rotation. It becomes possible.

  Furthermore, as a preferred example of the present invention, there is a method in which the slits are formed so as not to open from the both end portions of the magnet structure to the outer circumferential gap surface. By comprising in this way, this invention can be implemented more effectively.

  Furthermore, as a preferable example of the present invention, there is a case where the slit is formed from a long hole or a series of holes. By configuring in this way, the mechanical strength increases and the magnetic properties deteriorate due to work hardening around the hole, so that the rotor strength can be improved while having the same magnetic effect as the slit, up to high rotation It can be rotated.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

[Configuration of Rotating Electric Machine Targeted by the Present Invention]
FIG. 1 is a cross-sectional view for explaining an example of a rotating electrical machine that is an object of the rotor structure of the present invention. In addition, this example is a figure for demonstrating the structure of the whole rotary electric machine used as object, In this example, description of the part used as the characteristic of this invention is not performed. In the example shown in FIG. 1, a rotating electrical machine 1 that is an object of the present invention includes a stator 11, a stator 11, and a rotor 21 that is rotatably provided through a gap. The stator 11 is formed by winding a coil 13 around a plurality of teeth 12 that open to the gap surface. The rotor 21 is formed by embedding a plurality of permanent magnets 23 in the vicinity of the outer periphery of the core 22.

[Configurations Characterizing the Present Invention]
The feature of the present invention resides in that the shape of the permanent magnet 23 constituting the rotor 21 and the structure in the vicinity of the permanent magnet 23 are improved in the rotary electric machine 1 configured as described above. Hereinafter, the rotor structure of the rotating electrical machine of the present invention will be described in detail.

  The first feature of the present invention resides in the shape of the permanent magnet 23, which is a magnet structure having notches provided at both ends facing the outer periphery. FIGS. 2A to 2E are diagrams for explaining an example of a magnet structure in the rotor structure of the present invention.

In the example shown in FIG. 2A, the magnet structure 31 includes a rectangular magnet section 32 having a rectangular parallelepiped section, and a trapezoid whose section integrally provided on the outer periphery of the rectangular magnet section 32 is convex outward. And a magnet portion 33. In this example, the both ends of the trapezoidal magnet portion 33 constitute notches formed at both ends of the magnet structure 31. In the example shown in FIG. 2B, the magnet structure 31 is composed of a rectangular magnet section 32 having a rectangular parallelepiped section and a trapezoidal magnet having a section formed integrally with the outer periphery of the rectangular magnet section 32 and projecting outward. It is comprised from the part 33 and the barrier 34 which consists of the space | gap provided in the both ends of the trapezoid magnet part 33. FIG. In this example, the barriers 34 at both ends constitute notches formed at both ends of the magnet structure 31. In the example shown in FIG. 2C, the magnet structure 31 includes a rectangular magnet part 32 having a rectangular parallelepiped cross section and barriers 34 provided at both ends of the rectangular magnet part 32. In this example, the barriers 34 at both ends constitute notches formed at both ends of the magnet structure 31. In the example shown in FIG. 2D, the barrier 34 in the example shown in FIG. 2C is configured with a magnet 35, and the magnet 35 is configured integrally with the rectangular magnet portion 32. In this example, the magnets 35 at both ends constitute notches formed at both ends of the magnet structure 31. In the example shown in FIG. 2 (e), the magnet structure 31 is composed of a magnet 36 having a cross-sectional cross section and a larger curvature (= 1 / R) at both ends than at the center. In this example, the notch part formed in the both ends of the magnet structure 31 is comprised in the part with a large curvature of both ends.
In addition, the notch part should just have the long side part notched along the outer periphery of a rotor roughly.

  The second feature of the present invention is that a slit opened on the q-axis side is provided at a position corresponding to the notch at both ends of the magnet structure 31. FIGS. 3A and 3B are views for explaining an example of a magnet structure in the rotor structure of the present invention. In the example shown in FIG. 3A, the slit 41 is formed from the opening 42 provided in the outer peripheral gap surface toward the inner periphery. In the example shown in FIG. 3B, the slits 43 are formed so as not to open from the both end portions of the magnet structure 31 outward to the outer peripheral gap surface.

[Specific rotor structure of the present invention]
Next, a specific rotor structure of the present invention that can achieve iron loss reduction by combining the first feature (permanent magnet shape) and the second feature (slit) of the present invention described above will be described. 4 (a), 4 (b) to 7 (a), (b) are diagrams for explaining specific examples of the rotor structure of the present invention.

  In the examples shown in FIGS. 4A and 4B, the rectangular magnet portion 32 having a rectangular parallelepiped cross section and the rectangular magnet shown in FIG. 2B are used as the shape of the magnet structure 31 having the first characteristic. A magnet structure 31 comprising a trapezoidal magnet portion 33 whose section is integrally provided on the outer periphery of the portion 32 is convex outward, and a barrier 34 composed of a gap provided at both ends of the trapezoidal magnet portion 33. Used. As the second feature slit, the slit 41 shown in FIG. 3A is used in the example shown in FIG. 4A, while the slit shown in FIG. 3B is used in the example shown in FIG. 4B. 43 integrated with the barrier 34 is used.

  In the example shown in FIGS. 5A and 5B, as the shape of the magnet structure 31 having the first feature, a rectangular magnet section 32 having a rectangular parallelepiped section shown in FIG. A magnet structure 31 including a trapezoidal magnet portion 33 having a cross section integrally provided on the outer periphery of the magnet portion 32 and having a convex shape toward the outside is used. As the second feature slit, the slit 41 shown in FIG. 3A is used in the example shown in FIG. 5A, while the slit shown in FIG. 3B is used in the example shown in FIG. 5B. What provided 43 toward the outer peripheral side from the both ends of the magnet structure 31 is used.

  In the example shown in FIGS. 6A and 6B, as the shape of the magnet structure 31 having the first feature, a rectangular magnet section 32 having a rectangular parallelepiped section and a rectangular magnet shown in FIG. A magnet structure 31 including barriers 34 provided at both ends of the portion 32 is used. Further, as the second feature slit, the slit 41 shown in FIG. 3A is used in the example shown in FIG. 6A, while the slit shown in FIG. 3B is used in the example shown in FIG. 6B. 43 integrated with the barrier 34 is used.

  In the example shown in FIGS. 7A and 7B, the shape of the magnet structure 31 having the first feature is the same as shown in FIG. A magnet structure 31 composed of a large magnet 36 is used. As the second feature slit, the slit 41 shown in FIG. 3A is used in the example shown in FIG. 7A, while the slit shown in FIG. 3B is used in the example shown in FIG. 7B. What provided 43 toward the outer peripheral side from the both ends of the magnet structure 31 is used.

<About iron loss comparison of various shapes>
Next, the results of measuring the iron loss for a rotating electrical machine that actually has rotor structures of various shapes will be described. First, a rotor shown in FIGS. 8A to 8H is prepared as a rotor structure. Here, the example shown in FIG. 8A includes the outer slit 41, the magnet structure 31 including the rectangular magnet portion 32, the trapezoidal magnet portion 33, and the barrier 34 shown in FIG. 4A. Further, the example shown in FIG. 8B is configured by removing the slit 41 and the barrier 34 from the example shown in FIG. The example shown in FIG. 8C is configured by removing the slit 41 and leaving the barrier 34 from the example shown in FIG. The example shown in FIG. 8D is configured by removing the barrier 34 and leaving the slit 41 from the example shown in FIG. Further, in the example shown in FIG. 8E, the trapezoidal magnet portion 33 is removed from the magnet structure 31 in FIG. 8D, and the magnet structure 31 is configured by only the rectangular magnet portion 32. The example shown in FIG. 8 (f) is configured by adding barriers 34 having the same inclination on both ends of the magnet structure 31 in FIG. 8 (e). The example shown in FIG. 8G is configured by replacing the barrier 34 with a magnet in the example shown in FIG. The example shown in FIG. 8 (h) is configured as a trapezoidal magnet without the d-axis dent of the magnet structure 31 in the example shown in FIG. 8 (g).

With respect to the rotating electrical machine having the rotor structure shown in FIGS. 8A to 8H, the iron loss was measured under the following conditions.
(1) Driving conditions: Ia = 600 A, β = 80 deg, 8000 min ⁻¹
(2) Analysis method: sinusoidal current source magnetic field analysis by finite element method

FIG. 9 is a graph showing the iron loss rate in a rotating electrical machine having each rotor structure (FIGS. 8A to 8G). Here, the iron loss rate is obtained as iron loss rate = iron loss / output. Further, in FIG. 9, the reference numerals (a) to (g) correspond to FIGS. 8 (a) to (g). From the results shown in FIG. 9, the examples shown in FIGS. 8A, 8D, 8F, 8G, and 9H satisfying the rotor structure of the present invention are in any respect. It can be seen that the iron loss rate is significantly smaller than the examples of FIGS. 8B, 8C, and 8E that do not satisfy the structure.
FIG. 12 is a graph for comparing the iron loss in the example and the comparative example. In the example shown in FIG. 12, the relationship between the lead current phase angle β and the iron loss at a large current of 600 A and a small current of 200 A was examined for the present invention shape and the conventional shape. As can be seen from the results of FIG. 12, it can be seen that the increase in iron loss, which has conventionally occurred at a large current of 600 A, does not occur in the shape of the present invention.

<About the shapes of slits, barriers, etc.>
Next, a preferred example of the position of the slit 41, the position of the barrier 34, and the position of the rectangular magnet portion 32 in the rotor structure shown in FIG. As shown in FIG. 10, with respect to the upper part A of the barrier 34, the lower part B of the slit 41, the upper part C of the slit 41, and the thickness E of the magnet, the respective positions are swung to levels 1, 2, and 3 to form a rotor structure. FIG. 11 shows the change in the iron loss rate of the rotating electrical machine in a state of level 2 (intermediate between levels 1 and 3) except for the parameter of interest. From the results of FIG. 11, the level 1 for the upper part A of the barrier 34, the level 1 for the lower part B of the slit 41, the level 3 for the upper part C of the slit 41, and the level 1 for the magnet thickness E, respectively. It can be seen that the loss ratio is small.

<Summary of experimental results>
From the above, the following knowledge can be obtained.
(1) The slit contributes greatly to iron loss reduction.
(2) A wider angle between the slit and the barrier is effective in reducing iron loss. This can be considered because the effect of inducing the magnetic flux in the Q-axis direction is strengthened.
(3) Even if the barrier is removed and only the trapezoidal magnet is used, a sufficient iron loss reduction effect can be expected. Conversely, even when a rectangular magnet is used instead of a trapezoidal magnet, iron loss can be reduced by an appropriate barrier shape. Either the barrier or the trapezoidal part of the magnet can be used.

  In the above description, the skew with respect to the rotor has not been described. However, in addition to the above-described rotor structure of the present invention, a continuous skew structure or a step skew structure can be adopted. In the above-described rotor structure of the present invention, the magnetic flux is made sinusoidal in a two-dimensional cross section, and therefore the iron loss reduction effect does not deteriorate even if skewed. By skewing, it is possible to further improve cogging and torque ripple.

  According to the present invention, in the cross section, the magnet structure having notches provided at both ends facing the outer periphery, and opened to the q-axis side at positions corresponding to the notches at both ends of the magnet structure. By providing a rotor structure with a slit provided in a state, it is possible to eliminate magnetomotive force harmonics of the magnet, and to provide a rotating electrical machine that does not increase iron loss even during field weakening with a large current It can use suitably for the use to obtain.

It is a cross-sectional view for demonstrating an example of the rotary electric machine used as the object of the rotor structure of this invention. (A)-(e) is a figure for demonstrating an example of the magnet structure in the rotor structure of this invention, respectively. (A), (b) is a figure for demonstrating an example of the magnet structure in the rotor structure of this invention, respectively. (A), (b) is a figure for demonstrating a specific example of the rotor structure of this invention, respectively. (A), (b) is a figure for demonstrating the other specific example of the rotor structure of this invention, respectively. (A), (b) is a figure for demonstrating another specific example of the rotor structure of this invention, respectively. (A), (b) is a figure for demonstrating another specific example of the rotor structure of this invention, respectively. (A)-(h) is a figure which shows an example of the rotor structure which performs a characteristic comparison, respectively. It is a graph which shows the result of a characteristic comparison about Drawing 8 (a)-(h). It is a figure for demonstrating the suitable example of the slit in this invention, a barrier, and magnet thickness. It is a graph which shows the measurement result by FIG. It is a graph for comparing the iron loss in an Example and a comparative example. It is a graph for demonstrating the problem in the conventional rotary electric machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotating electric machine 11 Stator 12 Teeth 13 Coil 21 Rotor 22 Core 23 Permanent magnet 31 Magnet structure 32 Rectangular magnet part 33 Trapezoid magnet part 34 Barrier 35, 36 Magnet 41, 43 Slit 42 Opening part

Claims (7)

A rotor structure of a rotating electrical machine having a stator, and a rotor that is rotatably provided through a stator and a gap, and is configured by embedding a permanent magnet in a core, and a rectangular magnet section having a rectangular parallelepiped cross section And a magnet structure composed of a trapezoidal magnet portion whose cross section is integrally provided on the outer periphery of the rectangular magnet portion and outwardly convex, and a slit in the vicinity of both ends of the magnet structure. A rotor structure of a rotating electrical machine, wherein the outer peripheral side of the slit is provided to be inclined so as to approach the q-axis side . A rotor structure of a rotating electrical machine having a stator, and a rotor that is rotatably provided through a stator and a gap, and is configured by embedding a permanent magnet in a core, and a rectangular magnet section having a rectangular parallelepiped cross section And a magnet structure comprising a trapezoidal magnet part whose cross section is integrally provided on the outer periphery of the rectangular magnet part and a barrier provided at both ends of the trapezoidal magnet part, and a magnet structure A rotor structure for a rotating electrical machine, characterized in that a slit is provided at a position close to both ends of the body, and the outer peripheral side of the slit is inclined so as to approach the q-axis side . A rotor structure of a rotating electrical machine having a stator, and a rotor that is rotatably provided through a stator and a gap, and is configured by embedding a permanent magnet in a core, and a rectangular magnet section having a rectangular parallelepiped cross section And a magnet structure composed of barriers provided at both ends of the rectangular magnet portion, and slits at positions near the both ends of the magnet structure, and the outer periphery of the slit is inclined so as to approach the q-axis side rotor structure of a rotating electric machine thereby characterized in that provided is. A rotor structure of a rotating electrical machine having a stator and a rotor that is rotatably provided through a stator and a gap and is configured by embedding a permanent magnet in a core, and has a cross-sectional cross-sectional shape and ends of both ends. A magnet structure composed of magnets having a curvature (= 1 / R) larger than the center part, and slits at positions near both ends of the magnet structure, and the outer peripheral side of the slit is inclined so as to approach the q-axis side. A rotor structure of a rotating electrical machine characterized by being provided . 5. The rotor structure of a rotating electrical machine according to claim 1 , wherein the slit is formed toward an inner periphery from an opening provided in an outer peripheral gap surface. 5. The rotor of a rotating electrical machine according to claim 1 , wherein the slit is formed so as not to open to an outer peripheral gap surface from both ends of the magnet structure to the outside. Construction. The rotor structure of a rotating electrical machine according to any one of claims 1 to 6 , wherein the slit is formed from a long hole or a series of holes.

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