JP2017204962A - Dynamo-electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dynamo-electric machine in which magnetic flux of permanent magnets can be varied by a low cost configuration.SOLUTION: In a dynamo-electric machine including a stator 10 and a rotor 20, the stator 10 has multiple stator teeth 13 around which an armature coil 11 is wound concentrically, and the rotor 20 has multiple permanent magnet pairs 22 arranged in V-shape spreading toward the stator side, a rotor magnetic pole 23 formed of the permanent magnet pairs 22 arranged in V-shape, an induction coil 24 arranged closer to the stator side than the permanent magnet pair 22, and a magnetic path 25 arranged closer to the rotating shaft side than the permanent magnet pair 22. A cavity 40 is formed between the rotor magnetic pole 23 and a magnetic path 25, and a variable field coil 30 capable of adjusting the amount of magnetic flux from the permanent magnet pair 22 interlinking with the magnetic path 25 via the cavity 40, based on an induction current generated in the induction coil 24, is provided in the magnetic path 25.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rotating electrical machine.

  As a rotating electrical machine that outputs torque using the magnetic flux of a permanent magnet, a rotating electrical machine that can vary the amount of effective magnetic flux generated by the permanent magnet is known. For example, Patent Document 1 discloses a rotating electric machine having a stator around which an armature winding is wound and a rotor that is rotatably provided through the stator and a gap. A structure is described in which field magnets having two different polarities are alternately arranged in the rotation direction, each being divided into a first rotor and a second rotor.

  From such a structure, the rotating electrical machine described in Patent Document 1 operates the second rotor in accordance with changes in torque and rotational speed, and the polarity of the permanent magnet of the first rotor and the permanent magnet of the second rotor. By changing the positional relationship with the polarity, the effective magnetic flux amount by the permanent magnet can be adjusted. At this time, the rotating electrical machine described in Patent Document 1 changes the positional relationship between the polarity of the permanent magnet of the first rotor and the polarity of the permanent magnet of the second rotor according to the control signal input to the actuator. Control is performed so that the two rotors are positioned in a predetermined state.

JP 2010-246196 A

  However, the rotating electrical machine described in Patent Document 1 requires an actuator and a control device for controlling the actuator in order to position the second rotor in a predetermined state as described above. Further, since the second rotor is mechanically moved so that the first rotor and the second rotor have a predetermined positional relationship, precise control is required. For this reason, the magnetic flux of the permanent magnet cannot be varied with a low-cost configuration.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a rotating electrical machine that can vary the magnetic flux of a permanent magnet with a low-cost configuration.

  In order to achieve the above object, the present invention provides a rotating electrical machine including a stator having an armature coil and a rotor that rotates about a rotating shaft, wherein the armature coil is concentratedly wound on the stator. The rotor is formed by a plurality of permanent magnet pairs arranged in a V shape spreading toward the stator side, and the permanent magnet pairs arranged in a V shape. A magnetic pole portion, an induction coil disposed closer to the stator than the permanent magnet pair, and a magnetic path portion disposed closer to the rotating shaft than the permanent magnet pair, and the rotor magnetic pole portion and the An air gap is formed between the magnetic path portion and the magnetic path portion from the permanent magnet pair to the magnetic path portion via the air gap based on an induced current generated in the induction coil. Adjustable flux amount of interlinkage magnetic flux Characterized in that a variable field coil is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the rotary electric machine which can vary the magnetic flux of a permanent magnet with a low-cost structure can be provided.

FIG. 1 is a cross-sectional view of the rotating electrical machine according to the first embodiment of the present invention cut along a plane orthogonal to the rotation axis. FIG. 2 is a diagram showing the magnetic flux density and magnetic flux lines of the second-order spatial harmonics generated in the rotating electrical machine according to the first embodiment of the present invention. FIG. 3 is a circuit diagram showing the connection between the induction coil and variable field coil and the diode in the rotating electrical machine according to the first embodiment of the present invention. FIG. 4 is a schematic diagram showing a path of magnetic flux when the rotor of the rotating electrical machine according to the first embodiment of the present invention is rotating at a low speed. FIG. 5 is a diagram showing the amount of magnetic flux when the rotor of the rotating electrical machine according to the first embodiment of the present invention is rotating at a low speed. FIG. 6 is a schematic diagram showing a path of magnetic flux when the rotor of the rotating electrical machine according to the first embodiment of the present invention is rotating at a high speed. FIG. 7 is a diagram showing the amount of magnetic flux when the rotor of the rotating electrical machine according to the first embodiment of the present invention is rotating at a high speed. FIG. 8 is a cross-sectional view of the rotating electrical machine according to the second embodiment of the present invention cut along a plane orthogonal to the rotation axis. FIG. 9 is a diagram showing the magnetic flux density and magnetic flux lines of the second-order spatial harmonics generated in the rotating electrical machine according to the second embodiment of the present invention. FIG. 10 is a schematic diagram showing a path of magnetic flux when the rotor of the rotating electrical machine according to the second embodiment of the present invention is rotating at a low speed. FIG. 11 is a diagram showing the amount of magnetic flux when the rotor of the rotating electrical machine according to the second embodiment of the present invention is rotating at a low speed. FIG. 12 is a schematic diagram showing a path of magnetic flux when the rotor of the rotating electrical machine according to the second embodiment of the present invention is rotating at a high speed. FIG. 13 is a diagram showing the amount of magnetic flux when the rotor of the rotating electrical machine according to the second embodiment of the present invention is rotating at a high speed. FIG. 14 is a cross-sectional view showing a magnetic flux that is short-circuited between the stator teeth.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 to FIG. 7 are diagrams for explaining a rotating electrical machine according to a first embodiment of the present invention.

  As shown in FIG. 1, a rotating electrical machine 1 rotates by passing a magnetic flux generated in the stator 10 having a three-phase armature coil 11 of W phase, V phase, and U phase that generate magnetic flux when energized. A rotor 20 that rotates about a shaft 2 and a rectifier circuit 50 (see FIG. 3) are provided.

(Stator)
The stator 10 is fixed to a motor case (not shown). The stator 10 includes an annular stator core 12 made of a magnetic material having a high magnetic permeability. A plurality of stator teeth 13 protruding inward in the radial direction are formed on the stator core 12 along the circumferential direction.

  Slots 14 that are groove-like spaces are formed between stator teeth 13 that are adjacent in the circumferential direction. A radial direction shows the direction orthogonal to the direction where the rotating shaft 2 of the rotor 20 extends | stretches. The inward side in the radial direction indicates a side close to the rotating shaft 2 of the rotor 20 in the radial direction. The outer side in the radial direction indicates a side far from the rotating shaft 2 of the rotor 20 in the radial direction. The circumferential direction indicates a circumferential direction around the rotation axis 2 of the rotor 20. The radial direction is shown in the radial direction around the rotation axis 2.

  In each slot 14 of the stator core 12, a three-phase armature coil 11 of W phase, V phase, and U phase is arranged along the circumferential direction of the stator core 12. Each of the W-phase, V-phase, and U-phase armature coils 11 is wound around the stator teeth 13 by concentrated winding.

  Thus, the stator 10 has a plurality of stator teeth 13 around which the armature coils 11 are concentratedly wound. The stator 10 generates a rotating magnetic field that rotates in the circumferential direction when a three-phase alternating current is supplied to the armature coil 11. Magnetic flux generated in the stator 10 (hereinafter, this magnetic flux is referred to as “main magnetic flux”) is linked to the rotor 20. Thereby, the stator 10 can rotate the rotor 20.

  As described above, the stator 10 has the armature coil 11 concentratedly wound around the stator teeth 13. For this reason, when three-phase alternating current is supplied to the armature coil 11, the stator 10 generates a harmonic rotating magnetic field that is asynchronous with the rotation of the rotor 20 in addition to the rotating magnetic field that rotates in synchronization with the rotation of the rotor 20. To do. This harmonic rotating magnetic field includes second-order spatial harmonics in the stationary coordinate system (third-order time harmonics in the synchronous rotating coordinate system). Therefore, the harmonic component is superimposed on the magnetic flux generated in the stator 10.

(Rotor)
The rotor 20 is disposed on the radially inner side of the stator core 12 so that the outer peripheral surface faces the inner peripheral surface of the stator core 12.

  The rotor 20 includes a rotor core 21, a plurality of permanent magnet pairs 22, a rotor magnetic pole portion 23, an induction coil 24, and a magnetic path portion 25. As will be described later, the rotor 20 has a reverse salient pole structure having a plurality of permanent magnet pairs 22 in which a pair of permanent magnets 22A and 22B are arranged in a V shape.

  In the reverse salient pole structure, the inductance in the d-axis direction (d-axis inductance Ld) passing between the pair of permanent magnets 22A and 22B passes between the pair of permanent magnets 22 adjacent in the circumferential direction. It has characteristics smaller than the magnetically orthogonal q-axis direction inductance (q-axis inductance Lq). Therefore, in the reverse salient pole structure, in addition to the magnet torque generated by the permanent magnet pair 22, a reluctance torque corresponding to the difference between the d-axis inductance Ld and the q-axis inductance Lq can be generated. Thereby, the torque density in the rotary electric machine 1 can be improved.

  The rotor core 21 is made of a magnetic material having a high magnetic permeability, and is fixed to the rotary shaft 2 of the rotor 20 so as to be integrally rotatable. The rotating shaft 2 is fixed to the inner peripheral surface of the rotor core 21 and extends in a direction perpendicular to the radial direction of the rotor core 21. In the following, the direction in which the rotating shaft 2 extends is referred to as the axial direction.

  A pair of through holes 21 </ b> A and 21 </ b> B that penetrates the rotor core 21 in the axial direction are formed on the radially outer side of the rotor core 21. The pair of through holes 21 </ b> A and 21 </ b> B are arranged in a V shape that widens toward the stator 10 side. A pair of through-holes 21 </ b> A and 21 </ b> B arranged in a V shape is provided at a plurality of locations along the circumferential direction of the rotor core 21 at predetermined intervals.

  A pair of permanent magnets 22 is fitted into the inner side in the radial direction of the pair of through holes 21A and 21B, or is fitted by press-fitting or bonding. Further, a space in which the induction coil 24 is disposed adjacent to the permanent magnet pair 22 is provided on the radially outer side of the pair of through holes 21A and 21B.

  The permanent magnet pair 22 is composed of a permanent magnet 22A and a permanent magnet 22B arranged in a V-shape that expands toward the stator 10 side. A plurality of pairs of permanent magnets 22 are arranged at predetermined intervals in the circumferential direction of the rotor core 21, with the pair of permanent magnets 22 </ b> A and 22 </ b> B as one set.

  The permanent magnets 22A and 22B are constituted by, for example, columnar neodymium magnets (Nd-Fe-B magnets). The permanent magnets 22A and 22B are fitted into a pair of through holes 21A and 21B arranged in a V shape.

  The permanent magnet 22A and the permanent magnet 22B are arranged so that the same polar surfaces face each other. Thereby, between the permanent magnet 22A and the permanent magnet 22B, the rotor magnetic pole part 23 having the same polarity as the opposing polar surface is formed. Thus, the rotor magnetic pole portion 23 is formed as an N-pole or S-pole magnetic pole depending on the polarity of the permanent magnet pair 22 arranged in a V shape.

  The pair of permanent magnets 22A and 22B are arranged such that the directions of the polar surfaces of the permanent magnet pairs 22 adjacent in the circumferential direction are opposite to each other. Thereby, the polarity of the rotor magnetic pole part 23 is reversed between the rotor magnetic pole parts 23 adjacent in the circumferential direction.

  In the present embodiment, the permanent magnet pair 22 arranged so that the polar faces of the N poles face each other is called “N pole permanent magnet pair 22”, and the permanent magnets arranged so that the polar faces of the S poles face each other. The magnet pair 22 is referred to as “S-pole permanent magnet pair 22”.

  The induction coil 24 is disposed on the stator 10 side of the permanent magnet pair 22 and adjacent to the permanent magnet pair 22. Specifically, the induction coil 24 is wound so as to surround the rotor magnetic pole portion 23 using a space provided on the radially outer side of the pair of through holes 21A and 21B.

  The induction coil 24 generates an induction current based on a harmonic component superimposed on the magnetic flux generated on the stator 10 side. Specifically, when a three-phase alternating current is supplied to the armature coil 11 and a rotating magnetic field is generated in the stator 10, the harmonic component magnetic flux generated on the stator 10 side is linked to the induction coil 24. Thereby, the induction coil 24 induces an induced current.

  FIG. 2 shows the magnetic flux density and magnetic flux lines of the second spatial harmonic generated on the stator 10 side. FIG. 2 shows that the magnetic flux density is higher in the portion where the interval between the magnetic flux lines is narrower.

  As shown in FIG. 2, most of the magnetic flux of the second-order spatial harmonic generated on the stator 10 side is linked to the radially outer side of the rotor core 21. Therefore, in the present embodiment, since the induction coil 24 is wound so as to surround the rotor magnetic pole portion 23 on the outer side in the radial direction of the rotor core 21, more magnetic flux of the second-order spatial harmonics is transferred to the induction coil. 24 can be interlaced.

  The induction coil 24 is wound around the rotor magnetic pole portion 23 so that the energization direction is the same as that of the variable field coil 30 arranged in the radial direction with the induction coil 24. For this reason, the direction of the magnetic flux generated in the induction coil 24 when the induced current flows through the induction coil 24 and the direction of the induced magnetic flux generated in the variable field coil 30 coincide. This prevents the magnetic flux generated in the induction coil 24 from acting against the induced magnetic flux generated in the variable field coil 30. The variable field coil 30 will be described later.

  As shown in FIG. 1, a pair of through holes 21 </ b> C and 21 </ b> D that penetrate the rotor core 21 in the axial direction are formed on the radially inner side of the rotor core 21. The pair of through holes 21 </ b> C and 21 </ b> D are provided at a plurality of locations at predetermined intervals along the circumferential direction of the rotor core 21. The variable field coil 30 is arranged in the pair of through holes 21C and 21D.

  The magnetic path portion 25 is arranged on the radially inner side, that is, on the rotating shaft 2 side, than the permanent magnet pair 22. Specifically, the magnetic path portion 25 is formed integrally with the rotor core 21 so as to protrude from the inner side in the radial direction of the rotor core 21 toward the outer side between the pair of through holes 21C and 21D. Has been.

  The magnetic path portion 25 guides a part of the magnetic flux of the permanent magnet pair 22 to be short-circuited between the permanent magnet pairs 22 adjacent in the circumferential direction. In the magnetic path portion 25, a part of the magnetic flux generated by the N-pole permanent magnet pair 22 is linked as a short-circuit magnetic flux. The short-circuit magnetic flux linked to the magnetic path portion 25 is guided to the S-pole permanent magnet pair 22. Thereby, a part of the magnetic flux generated in the permanent magnet pair 22 is short-circuited between the permanent magnet pairs 22 adjacent in the circumferential direction.

  The magnetic path portion 25 is disposed so as to extend in the radial direction on each d-axis between the pair of permanent magnets 22A and 22B. A variable field coil 30 is concentratedly wound around the magnetic path portion 25. The variable field coil 30 is wound around the magnetic path portion 25 using a pair of through holes 21 </ b> C and 21 </ b> D adjacent to the magnetic path portion 25.

  The variable field coil 30 is a coil that can adjust the amount of short-circuit magnetic flux linked to the magnetic path portion 25 from the permanent magnet pair 22 via the gap 40 according to the magnitude of the induced current generated in the induction coil 24. It is. The gap 40 will be described later.

  The variable field coil 30 is concentratedly wound around the magnetic path portion 25 so as to have an energization direction that generates an induced magnetic flux in a direction in which the magnetic flux is short-circuited between adjacent permanent magnet pairs 22. The adjacent permanent magnet pairs 22 are the permanent magnet pairs 22 that respectively form the rotor magnetic pole portions 23 adjacent in the circumferential direction.

  “The direction in which the magnetic flux is short-circuited between the adjacent permanent magnet pairs 22” means that the magnetic path portion 25 arranged on the radially inner side of the N-pole permanent magnet pair 22 is radially outward. In the magnetic path portion 25 that is directed from the inner side toward the inner side and is disposed on the inner side in the radial direction of the S-pole permanent magnet pair 22, the inner side in the radial direction is moved outward. The direction is heading.

  Thereby, when the direct current rectified by the rectifier circuit 50 is supplied, the variable field coil 30 generates an induced magnetic flux in a direction in which the magnetic flux is short-circuited between the adjacent permanent magnet pairs 22. .

  The amount of induction magnetic flux generated by the variable field coil 30 is adjusted according to the magnitude of the direct current supplied to the variable field coil 30. By adjusting the magnetic flux amount of the induced magnetic flux, the magnetic flux amount of the short-circuit magnetic flux between the adjacent permanent magnet pairs 22 is adjusted.

  The amount of the induced magnetic flux increases as the direct current supplied to the variable field coil 30 increases and the number of turns of the variable field coil 30 increases. The number of turns of the variable field coil 30 is set to the number of turns obtained experimentally in advance.

  The direct current supplied to the variable field coil 30 is adjusted according to the magnitude of the induced current generated in the induction coil 24. Thus, the magnetic flux amount of the short-circuit magnetic flux is adjusted according to the magnitude of the induced current generated in the induction coil 24. Further, the induced current generated in the induction coil 24 increases as the rotational speed of the rotor 20 increases. Therefore, the magnetic flux amount of the short-circuit magnetic flux increases as the rotational speed of the rotor 20 increases.

  A gap 40 having a predetermined size is formed between the rotor magnetic pole part 23 and the magnetic path part 25 as a high magnetic resistance region. When the direct current is not supplied to the variable field coil 30, the air gap 40 does not flow between the rotor magnetic pole portion 23 and the magnetic path portion 25, or a minute amount even if the magnetic flux of the permanent magnet pair 22 flows. It is such a size. The gap 40 is set to a size such that the magnetic flux of the permanent magnet pair 22 flows between the rotor magnetic pole portion 23 and the magnetic path portion 25 when a direct current is supplied to the variable field coil 30. Yes.

  The gap 40 is formed so as to penetrate the rotor core 21 in the axial direction. The air gap 40 is a space defined by the radially inner surface of the rotor magnetic pole portion 23 and the permanent magnet pair 22 and the radially outer surface of the magnetic path portion 25 and the variable field coil 30. It is.

  In the gap 40, a portion that protrudes outward in the radial direction from the inner peripheral surface in the radial direction of the pair of permanent magnets 22 between the pair of permanent magnets 22 </ b> A and 22 </ b> B extends from the inner side in the radial direction to the outer side. The taper is formed so that the width in the circumferential direction becomes smaller as it goes. In this embodiment, a trapezoidal shape is adopted as the tapered shape.

  Thus, the space | interval which arrange | positions the variable field coil 30 can be taken large because the space | gap 40 protrudes to the outer side of radial direction. As a result, the number of turns of the variable field coil 30 can be increased, and more induction magnetic flux can be generated. In addition, when the space for arranging the variable field coil 30 can be sufficiently secured, the tapered portion as described above may not be formed in the gap 40.

  The taper shape is not limited to a trapezoidal shape, but may be various shapes as long as the circumferential width decreases from the radially inward side to the outward side, such as a triangular shape, a semicircular shape, and a warhead shape. Shape can be adopted.

  In the present embodiment, the gap 40 is defined including the gap between the permanent magnet pair 22 and the variable field coil 30, but is defined by the rotor magnetic pole portion 23 and the magnetic path portion 25 without the gap. The space may be a gap 40.

  Further, a bridge portion that connects the rotor magnetic pole portion 23 and the magnetic path portion 25 may be formed between the rotor magnetic pole portion 23 and the magnetic path portion 25. In this case, the strength of the rotor core 21 can be increased. However, the circumferential width of the bridge portion is preferably narrow so that the magnetic flux of the permanent magnet pair 22 does not leak to the magnetic path portion 25 side through the bridge portion when the rotor rotates at a low speed.

(Rectifier circuit)
The rotating electrical machine 1 includes a rectifier circuit 50 that rectifies an alternating induced current induced by the induction coil 24 into a direct current and supplies the rectified current to the variable field coil 30.

  As shown in FIG. 3, the rectifier circuit 50 includes two diodes D1 and D2 as rectifier elements, and a closed circuit in which the diodes D1 and D2, the two induction coils 24, and the two variable field coils 30 are connected. It is configured as.

  The diodes D1 and D2 are provided on the rotor 20 in a state of being housed in a diode case (not shown), for example. The diodes D1 and D2 may be mounted inside the rotor 20.

  In the rectifier circuit 50, the AC induced current generated in the two induction coils 24 is rectified by the diodes D1 and D2, and the rectified DC current is applied to the two variable field coils 30 connected in series. Supplied as The two variable field coils 30 generate an induced magnetic flux when supplied with a direct current.

(Operation of rotating electrical machine)
Next, the operation of the rotating electrical machine 1 according to the present embodiment will be described with reference to FIGS.

  As described above, the rotating electrical machine 1 according to the present embodiment is a permanent magnet type synchronous motor that includes the permanent magnet pair 22 in the rotor 20 and outputs torque using the magnetic flux of the permanent magnet pair 22.

  In the conventional permanent magnet type synchronous motor, since the magnetic flux of the permanent magnet is constant, the counter electromotive force generated in the armature coil of the stator is increased by the magnetic flux of the permanent magnet as the rotational speed of the rotor increases. When the rotational speed of the rotor reaches a certain rotational speed, the counter electromotive force generated in the armature coil becomes equal to the power supply voltage of the permanent magnet type synchronous motor. As a result, no more current can flow through the permanent magnet type synchronous motor. As a result, the rotational speed of the rotor cannot be increased.

  Conventionally, in order to solve such problems, field weakening control has been performed in which a counter electromotive force generated in the armature coil is equivalently reduced by passing a current that cancels the magnetic flux generated by the permanent magnet through the armature coil of the stator.

  However, this field weakening control generates a magnetic flux that does not contribute to torque because a current is supplied to generate a magnetic flux in a direction that cancels the magnetic flux of the permanent magnet. This has led to a decrease in efficiency.

  Further, in the field weakening control, a harmonic magnetic flux is generated, and therefore the iron loss and electromagnetic vibration of the permanent magnet type synchronous motor may increase due to the harmonic magnetic flux. Further, in the field weakening control, since the magnetic flux in the direction opposite to the magnetic flux of the permanent magnet is generated to suppress the magnetic flux of the permanent magnet, irreversible demagnetization of the permanent magnet may occur. For this reason, it is necessary to use a permanent magnet having a relatively high coercive force, which increases costs.

  When a neodymium magnet is used as the permanent magnet, an eddy current is generated in the permanent magnet due to fluctuations in the external magnetic field by field weakening control, and the permanent magnet generates heat. This heat generation may cause irreversible demagnetization of the permanent magnet. Therefore, it is necessary to add a material such as a rare earth having high heat resistance to the permanent magnet. However, in this case, since the added material such as rare earth becomes an impurity for the permanent magnet, the original performance of the permanent magnet may not be exhibited.

  Therefore, in the rotating electrical machine 1 according to the present embodiment, the amount of magnetic flux interlinked from the permanent magnet pair 22 to the stator 10 by the action of the magnetic path portion 25 and the variable field coil 30 described above without performing field weakening control. Adjustable configuration. Thereby, the rotary electric machine 1 which concerns on this Embodiment can solve the problem by the field weakening control as mentioned above.

(When rotor is running at low speed)
In the rotating electrical machine 1 according to the present embodiment, when the rotational speed of the rotor 20 is low, the magnetic flux of the higher harmonic component is not generated in the stator 10 or is very small even if it is generated. For this reason, the variable field coil 30 does not generate the induced magnetic flux, or even if it generates a very small amount.

  Therefore, in the gap 40, the magnetic resistance is high. For this reason, the magnetic flux of the N-pole permanent magnet pair 22 does not interlink with the magnetic path portion 25 via the air gap 40 or only interlinks slightly. Therefore, the magnetic flux of the N-pole permanent magnet pair 22 is not short-circuited to the S-pole permanent magnet pair 22 or is slightly short-circuited. As a result, when the rotational speed of the rotor 20 is low, as shown in FIGS. 4 and 5, all or most of the magnetic flux of the permanent magnet pair 22 (indicated by white arrows in FIG. 4) is transferred to the stator 10. Interlink.

  Thus, when the rotational speed of the rotor 20 is low, the amount of magnetic flux interlinked from the permanent magnet pair 22 to the stator 10 can be increased compared to when the rotational speed of the rotor 20 described later is high.

(At high rotor speed)
In the rotating electrical machine 1 according to the present embodiment, when the rotational speed of the rotor 20 is high, a harmonic component magnetic flux is generated in the stator 10. The amount of the harmonic component magnetic flux increases as the rotational speed of the rotor 20 increases.

  When the magnetic flux of the harmonic component is linked to the induction coil 24, an induced current is induced in the induction coil 24 of the rotor 20, and the induced current is rectified by the rectifier circuit 50 (see FIG. 3) to be a direct current. Is supplied to the variable field coil 30.

  The variable field coil 30 to which the direct current is supplied generates an induced magnetic flux so that the magnetic flux is short-circuited between the adjacent permanent magnet pairs 22. Along with this, the magnetic resistance in the air gap 40 decreases.

  As described above, when the magnetic resistance in the gap 40 decreases, a part of the magnetic flux of the N-pole permanent magnet pair 22 is short-circuited as shown in FIGS. 6 and 7 (indicated by black arrows in FIG. 6). As shown in FIG. The short-circuit magnetic flux linked to the magnetic path portion 25 is short-circuited to the S-pole permanent magnet pair 22 via the magnetic path portion 25 and the rotor core 21. As a result, a magnetic flux having a magnetic flux amount excluding the magnetic flux amount of the short-circuit magnetic flux among the total magnetic flux amount of the permanent magnet pair 22 (shown by a white arrow in FIG. 6) is linked to the stator 10. That is, when the rotational speed of the rotor 20 is high, the amount of magnetic flux interlinked from the permanent magnet pair 22 to the stator 10 is suppressed compared to when the rotational speed of the rotor 20 is low.

  Therefore, even if the rotational speed of the rotor 20 is high, field-weakening control can be made unnecessary. For this reason, the iron loss and electromagnetic vibration resulting from the harmonic magnetic flux produced by field weakening control can be prevented.

  Further, since field weakening control is not required, it is not necessary to use a permanent magnet having a high coercive force, and it is not necessary to add a material such as a rare earth having a high heat resistance to the permanent magnet. Thereby, the cost of the rotary electric machine 1 can be reduced.

  Thus, in the rotating electrical machine 1 according to the present embodiment, the amount of magnetic flux interlinking from the permanent magnet pair 22 to the stator 10 can be adjusted without performing field-weakening control. Specifically, when the rotational speed of the rotor 20 is high, a decrease in efficiency can be prevented. Further, the output can be improved when the rotational speed of the rotor 20 is low.

  As described above, according to the rotating electrical machine 1 of the present embodiment, an induced current is generated by linking the harmonic component superimposed on the magnetic flux generated on the stator 10 side to the induction coil 24, and the induced current Is rectified by the rectifier circuit 50 and supplied to the variable field coil 30. Thereby, the magnetic flux amount of the short circuit magnetic flux which short-circuits between the permanent magnet pairs 22 adjacent to the circumferential direction can be adjusted.

  The harmonic component superimposed on the magnetic flux generated on the stator 10 side is obtained by supplying a three-phase alternating current to the armature coil 11 concentratedly wound on the stator 10. For this reason, in order to generate the direct current supplied to the variable field coil 30, no special device such as a DC / DC converter is required.

  As a result, the rotating electrical machine 1 according to the present embodiment adjusts the amount of magnetic flux interlinked from the permanent magnet pair 22 to the stator 10 with a simple configuration without using a special device such as a DC / DC converter. can do. As a result, the rotating electrical machine 1 of the present embodiment can vary the magnetic flux of the permanent magnet pair 22 with a low-cost configuration.

[Second Embodiment]
8 to 13 are diagrams for explaining a rotating electrical machine according to a second embodiment of the present invention.

  The rotating electrical machine 201 of the present embodiment is partially different from the rotating electrical machine 1 of the first embodiment in the configuration of the rotor, but the other configurations are the same. In the following, the same reference numerals are used for the same configurations of the first embodiment.

  As shown in FIG. 8, the rotating electrical machine 201 according to the present embodiment includes a stator 10, a rotor 220, and a rectifier circuit 50 (see FIG. 3).

  In the rotor 220 of the present embodiment, a through hole 21E that penetrates the rotor core 21 in the axial direction is formed between the pair of through holes 21A and the through holes 21B on the outer side in the radial direction of the rotor magnetic pole portion 23. Is formed.

  The through holes 21 </ b> E are formed in an elongated shape in the circumferential direction of the rotor core 21, and are provided at a plurality of locations at predetermined intervals along the circumferential direction of the rotor core 21. An auxiliary magnet 222, which will be described later, is fitted into the intermediate position in the circumferential direction of the through hole 21E, or is fitted by press fitting or adhesion.

  Further, flux barriers 250 are formed on both end sides in the circumferential direction of the through hole 21E so as to be adjacent to the auxiliary magnet 222 in the circumferential direction. The flux barrier 250 includes a space defined by the inner peripheral surface of the through-hole 21E and the circumferential side surface of the auxiliary magnet 222.

  The rotor 220 of the present embodiment includes an auxiliary magnet 222 in addition to the permanent magnet pair 22 as a permanent magnet that generates magnetic flux. The auxiliary magnet 222 is composed of, for example, a columnar neodymium magnet (Nd—Fe—B magnet). The auxiliary magnet 222 is fitted in the through hole 21E described above. Thus, the auxiliary magnet 222 is disposed on the radially outer side of the rotor magnetic pole portion 23.

  The auxiliary magnet 222 is disposed so that a polar surface having a polarity opposite to the polarity formed in the rotor magnetic pole portion 23 by the permanent magnet pair 22 faces the inner side in the radial direction. For example, with respect to the N-pole permanent magnet pair 22, the auxiliary magnet 222 is arranged so that the polar face of the S-pole faces inward in the radial direction.

  Thereby, the direction of the magnetic flux of the permanent magnet pair 22 and the direction of the magnetic flux of the auxiliary magnet 222 coincide. Therefore, the auxiliary magnet 222 does not hinder the flow of magnetic flux of the permanent magnet pair 22. In addition to the magnetic flux of the permanent magnet pair 22, the magnetic flux of the auxiliary magnet 222 can be linked to the stator 10.

  Further, in the rotor 220 of the present embodiment, a bridge portion 260 that connects the rotor magnetic pole portion 23 and the magnetic path portion 25 is formed on the d-axis between the rotor magnetic pole portion 23 and the magnetic path portion 25. Yes. Thereby, the strength of the rotor core 21 is increased. However, the circumferential width of the bridge portion 260 is set to a narrow width so that the magnetic flux of the permanent magnet pair 22 does not leak to the magnetic path portion 25 side via the bridge portion 260 when the rotor is rotating at a low speed. If the strength of the rotor core 21 can be ensured, the bridge portion 260 may not be provided.

  FIG. 9 shows the magnetic flux density and magnetic flux lines of the second-order spatial harmonics generated on the stator 10 side. FIG. 9 shows that the magnetic flux density is higher in the portion where the interval between the magnetic flux lines is narrower.

  As shown in FIG. 9, also in the present embodiment, most of the magnetic flux of the second-order spatial harmonics generated on the stator 10 side is linked to the outer side in the radial direction of the rotor core 21 of the rotor 220. . Therefore, also in the present embodiment, since the induction coil 24 is wound so as to surround the rotor magnetic pole portion 23 on the outer side in the radial direction of the rotor core 21, more magnetic flux of the second-order spatial harmonics is transferred to the induction coil. 24 can be interlaced.

(Operation of rotating electrical machine)
Next, the operation of the rotating electrical machine 201 according to the present embodiment will be described with reference to FIGS.

(When rotor is running at low speed)
In the rotating electrical machine 201 according to the present embodiment, when the rotational speed of the rotor 220 is low, a harmonic component magnetic flux is not generated in the stator 10, or a minute amount is generated even if it is generated. For this reason, the variable field coil 30 does not generate the induced magnetic flux, or even if it generates a very small amount.

  Therefore, in the gap 40, the magnetic resistance is high. For this reason, the magnetic flux of the N-pole permanent magnet pair 22 does not interlink with the magnetic path portion 25 via the air gap 40 or only interlinks slightly. Therefore, the magnetic flux of the N-pole permanent magnet pair 22 is not short-circuited to the S-pole permanent magnet pair 22 or is slightly short-circuited. As a result, when the rotational speed of the rotor 220 is low, as shown in FIGS. 10 and 11, all or most of the magnetic flux of the permanent magnet pair 22 (indicated by white arrows in FIG. 10) and the auxiliary magnet 222. The magnetic flux is interlinked with the stator 10.

  Thus, when the rotational speed of the rotor 220 is low, the amount of magnetic flux interlinked from the permanent magnet pair 22 to the stator 10 can be increased compared to when the rotational speed of the rotor 220 described later is high.

(At high rotor speed)
In the rotating electrical machine 201 according to the present embodiment, when the rotational speed of the rotor 220 is high, a magnetic flux of harmonic components is generated in the stator 10. The amount of the harmonic component magnetic flux increases as the rotational speed of the rotor 220 increases.

  The magnetic flux of this harmonic component is linked to the induction coil 24, so that an induced current is induced in the induction coil 24 of the rotor 220, and the induced current is rectified by the rectifier circuit 50 (see FIG. 3) to generate a direct current. Is supplied to the variable field coil 30.

  The variable field coil 30 to which the direct current is supplied generates an induced magnetic flux so that the magnetic flux is short-circuited between the adjacent permanent magnet pairs 22. Along with this, the magnetic resistance in the air gap 40 decreases.

  When the magnetic resistance in the air gap 40 decreases as described above, a part of the magnetic flux of the N-pole permanent magnet pair 22 is short-circuited as shown in FIGS. 12 and 13 (indicated by black arrows in FIG. 12). As shown in FIG. The short-circuit magnetic flux linked to the magnetic path portion 25 is short-circuited to the S-pole permanent magnet pair 22 via the magnetic path portion 25 and the rotor core 21. As a result, a magnetic flux (indicated by a white arrow in FIG. 12) obtained by adding the magnetic flux amount of the auxiliary magnet 222 to the magnetic flux amount excluding the short-circuit magnetic flux amount out of the total magnetic flux amount of the permanent magnet pair 22 is obtained. Link to 10. That is, when the rotational speed of the rotor 220 is high, the amount of magnetic flux interlinked from the permanent magnet pair 22 to the stator 10 is suppressed compared to when the rotational speed of the rotor 220 is low.

  Therefore, also in the rotating electrical machine 201 of the present embodiment, field weakening control can be made unnecessary, and iron loss and electromagnetic vibration due to harmonic magnetic flux generated by field weakening control can be prevented.

  Further, since field weakening control is not required, it is not necessary to use a permanent magnet having a high coercive force, and it is not necessary to add a material such as a rare earth having a high heat resistance to the permanent magnet. Thereby, the cost of the rotary electric machine 201 can be reduced.

  Thus, also in the rotating electrical machine 201 according to the present embodiment, the amount of magnetic flux interlinking from the permanent magnet pair 22 to the stator 10 can be adjusted without performing field-weakening control. Specifically, when the rotational speed of the rotor 220 is high, it is possible to prevent a decrease in efficiency. Further, when the rotational speed of the rotor 220 is low, the output can be improved.

(Operation of auxiliary magnet and flux barrier)
FIG. 14 shows a rotating electrical machine 301 that does not include the auxiliary magnet 222 and the flux barrier 250. The rotating electrical machine 301 is different from the rotating electrical machine 201 of the present embodiment in that the auxiliary magnet 222 and the flux barrier 250 are not included, but the other configurations are the same as the rotating electrical machine 201. About the same structure as the rotary electric machine 201, the same code | symbol as this Embodiment is used.

  As shown in FIG. 14, in the stator 10 in which the armature coil 11 is concentratedly wound, the magnetic poles of the adjacent stator teeth 13 may be opposite magnetic poles. In this case, as shown by an arrow A in FIG. 14 between adjacent stator teeth 13, a part of the main magnetic flux generated in the stator 10 is short-circuited via the rotor magnetic pole portion 23.

  The amount of magnetic flux that is short-circuited between adjacent stator teeth 13 differs between when the rotor is rotating at a low speed and when the rotor is rotating at a high speed. When the rotor is rotating at a low speed, the amount of magnetic flux interlinked from the permanent magnet pair 22 to the stator 10 is large. Therefore, the magnetic flux of the permanent magnet pair 22 acts to cancel the main magnetic flux that is short-circuited between the adjacent stator teeth 13. Thereby, at the time of rotor low rotation, the magnetic flux amount which short-circuits between the adjacent stator teeth 13 is suppressed.

  As described above, the amount of magnetic flux interlinked from the permanent magnet pair 22 to the stator 10 is reduced when the rotor is rotating at a high speed. Therefore, the amount of magnetic flux that is short-circuited between adjacent stator teeth 13 is increased compared to when the rotor is rotating at a low speed. To do.

  Here, in the armature coil 11, the magnetic flux of the permanent magnet pair 22 and the main magnetic flux that is short-circuited between the adjacent stator teeth 13 as described above are linked. The induced electromotive force generated in the armature coil 11 is obtained by time-differentiating Φ when the total number of magnetic fluxes linked to the armature coil 11 is “Φ”. That is, the induced electromotive force V generated in the armature coil 11 is “V = −dΦ / dt”.

  For this reason, if the amount of magnetic flux that is short-circuited between the adjacent stator teeth 13 increases even though the amount of magnetic flux of the permanent magnet pair 22 is reduced, the total number of magnetic fluxes linked to the armature coil 11 is calculated. It cannot be reduced.

  As a result, when the rotor is rotating at high speed, the induced electromotive force generated in the armature coil 11 is reduced even though the amount of magnetic flux of the permanent magnet pair 22 is reduced in order to reduce the induced electromotive force generated in the armature coil 11. Not happen.

  In the rotating electrical machine 201 according to the present embodiment, the auxiliary magnet 222 and the flux described above on the radially outer side of the rotor magnetic pole portion 23 so that the main magnetic flux is not short-circuited between the adjacent stator teeth 13 at the time of high rotor rotation. A barrier 250 was provided.

  The auxiliary magnet 222 and the flux barrier 250 function as a high magnetic resistance region when the rotor rotates at a high speed, thereby suppressing the main magnetic flux from being short-circuited between the adjacent stator teeth 13.

  As described above, according to the rotating electrical machine 201 of the present embodiment, an induced current is generated by interlinking the harmonic component superimposed on the magnetic flux generated on the stator 10 side with the induction coil 24, and the induced current Is rectified by the rectifier circuit 50 and supplied to the variable field coil 30. Thereby, the magnetic flux amount of the short circuit magnetic flux which short-circuits between the permanent magnet pairs 22 adjacent to the circumferential direction can be adjusted.

  The harmonic component superimposed on the magnetic flux generated on the stator 10 side is obtained by supplying a three-phase alternating current to the armature coil 11 concentratedly wound on the stator 10. For this reason, in order to generate the direct current supplied to the variable field coil 30, no special device such as a DC / DC converter is required.

  As a result, the rotating electrical machine 201 of the present embodiment adjusts the amount of magnetic flux interlinked from the permanent magnet pair 22 to the stator 10 with a simple configuration without using a special device such as a DC / DC converter. can do. As a result, the rotating electrical machine 201 of the present embodiment can vary the magnetic flux of the permanent magnet pair 22 with a low-cost configuration.

  Further, in the rotating electrical machine 201 of the present embodiment, since the auxiliary magnet 222 and the flux barrier 250 are provided on the radially outer side of the rotor magnetic pole portion 23, the main magnetic flux between the adjacent stator teeth 13 during high rotor rotation. Can be prevented from short-circuiting. Thereby, the total number of magnetic fluxes linked to the armature coil 11 at the time of high rotor rotation can be reduced. Therefore, the induced electromotive force generated in the armature coil 11 at the time of high rotor rotation can be reduced.

  The rotating electrical machines of the first and second embodiments described above can be suitably employed as, for example, an in-vehicle motor, a wind power generator, or a machine tool motor.

  In the first and second embodiments described above, the rotary electric machine is applied to a radial gap type rotary electric machine, but may be applied to an axial gap type rotary electric machine.

  In the rotating electrical machines of the first and second embodiments described above, the ratio of the number of slots 14 of the stator 10 to the number of rotor magnetic pole portions 23 of the rotor 20, that is, the slot combination of the stator 10 and the rotor 20 is “3: 2 ”, the combination of the number of slots 14 and the number of rotor magnetic pole portions 23 may be any combination.

  While embodiments of the invention have been disclosed, it will be apparent to those skilled in the art that changes may be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims.

DESCRIPTION OF SYMBOLS 1,201 Rotating electrical machine 2 Rotating shaft 10 Stator 11 Armature coil 13 Stator teeth 20, 220 Rotor 22 Permanent magnet pair 22A, 22B Permanent magnet 23 Rotor magnetic pole part 24 Inductive coil 25 Magnetic path part 30 Variable field coil 40 Gap 50 Rectification Circuit 222 Auxiliary magnet 250 Flux barrier 260 Bridge part D1, D2 Diode

Claims (5)

A rotating electrical machine comprising a stator having an armature coil and a rotor that rotates about a rotation axis,
The stator is
The armature coil has a plurality of stator teeth wound in a concentrated manner,
The rotor is
A plurality of permanent magnet pairs arranged in a V-shape extending toward the stator side;
A rotor magnetic pole portion formed by the pair of permanent magnets arranged in a V shape;
An induction coil disposed closer to the stator than the permanent magnet pair;
A magnetic path portion disposed closer to the rotating shaft than the permanent magnet pair,
A gap is formed between the rotor magnetic pole part and the magnetic path part,
The magnetic path portion has a variable field coil capable of adjusting a magnetic flux amount of a magnetic flux linked to the magnetic path portion from the permanent magnet pair via the gap based on an induced current generated in the induction coil. A rotating electric machine characterized by being provided.   The rotating electrical machine according to claim 1, wherein the induction coil is disposed adjacent to the permanent magnet pair.   3. The rotating electrical machine according to claim 1, wherein the magnetic path portion is arranged to extend in a radial direction on a d-axis between the pair of permanent magnets.   4. The bridge portion for connecting the rotor magnetic pole portion and the magnetic path portion is formed between the rotor magnetic pole portion and the magnetic path portion. 5. The rotating electrical machine according to item 1. The rotor includes an auxiliary magnet disposed on the radially outer side of the rotor magnetic pole portion,
In the rotor magnetic pole part, a flux barrier is formed so as to be adjacent to the auxiliary magnet in the circumferential direction,
The auxiliary magnet is arranged such that a polar surface having a polarity opposite to a polarity formed in the rotor magnetic pole portion by the permanent magnet pair faces an inner side in a radial direction. The rotating electrical machine according to any one of 4.

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