JP2017169281A - Rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary electric machine that allows a magnetic flux of a permanent magnet to be varied with a structure at low cost.SOLUTION: A stator 10 has: an annular stator core 12; and an armature coil 11 toroidally wound between adjacent stator teeth 13. A rotor 20 has: first rotor teeth 212 opposing to the stator teeth 13 in a shaft direction of the stator core 12; second rotor teeth 212 opposing to the stator teeth 13 inward in a radial direction of the stator core 12; induction coils 215 wound around the first rotor teeth 212; a permanent magnet 223 arranged in the second rotor teeth 222; a magnetic path member 225 that guides part of a magnetic flux of the permanent magnet 223; and a variable field coil 226 provided in the magnetic path member 225. The stator core 12 has a slot 14 having the same shape as the shape of the first rotor teeth 212, between adjacent stator teeth 13.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 Literature 1 controls the input to the actuator in changing the relative positional relationship between the polarity of the permanent magnet of the first rotor and the polarity of the permanent magnet of the second rotor. The second rotor is controlled to be positioned in a predetermined state by the signal.

  In a state where the second rotor is moved to an arbitrary predetermined position separated from the first rotor in the rotation axis direction, the magnetic flux generated in the rotation axis direction can be blocked by the magnetoresistive layer provided on the stator core. it can. Thereby, the iron loss in the high-speed rotation area | region of a magnetic flux variable type rotary electric machine can be reduced.

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 comprising a stator having an armature coil and a rotor having a permanent magnet, wherein the stator is a plurality of coils arranged at predetermined intervals in the circumferential direction. An annular stator core having stator teeth, and an armature coil wound toroidally between adjacent stator teeth, wherein the rotor is formed on at least one surface in the axial direction of the stator core on the stator. A first rotor tooth facing the teeth, a second rotor tooth facing the stator teeth on the radially inner side of the stator core, and the first rotor teeth wound around the stator side. An induction coil that generates an induced current based on the generated magnetic flux, a permanent magnet disposed in the second rotor teeth, and the permanent magnet A magnetic path member arranged around a stone and guiding a part of the magnetic flux of the permanent magnet; and a magnetic path member provided in the magnetic path member and guided to the magnetic path member based on an induced current generated in the induction coil. The stator core has a groove having the same shape as that of the first rotor tooth between the adjacent stator teeth.

  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 partial cross-sectional perspective view of a rotating electrical machine according to an embodiment of the present invention. FIG. 2 is a perspective view of the stator of the rotating electrical machine according to the embodiment of the present invention. FIG. 3 is a plan view of the rotating electrical machine according to the embodiment of the present invention, and is a diagram showing the shapes and arrangement of the first rotor teeth and the stator teeth. FIG. 4 is a connection diagram of the induction coil, variable field coil, and rectifier circuit in the rotating electrical machine according to the embodiment of the present invention. FIG. 5 is a schematic diagram showing the amount of magnetic flux interlinked from the rotor to the stator when the rotor of the rotating electrical machine according to the embodiment of the present invention is rotating at a low speed. FIG. 6 is a schematic diagram showing the amount of magnetic flux interlinked from the rotor to the stator when the rotor of the rotating electrical machine according to the embodiment of the present invention is rotating at a high speed. FIG. 7 is a diagram showing the phase control of the armature current vector when the induction magnetic flux is generated by the variable field coil in the rotating electric machine according to the embodiment of the present invention. FIG. 8 is a diagram showing current phase characteristics of the induced electromotive force of the armature coil in the rotating electrical machine according to the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 8 are diagrams illustrating a rotating electrical machine according to an embodiment of the present invention.

  As shown in FIGS. 1 and 2, the rotating electrical machine 1 includes a stator 10 having a three-phase armature coil 11 of W phase, V phase, and U phase that generates magnetic flux when energized, and magnetic flux generated in the stator 10. And a rotor 20 that rotates by passage.

(Stator)
The stator 10 includes an annular stator core 12 made of a magnetic material having a high magnetic permeability, and an armature coil 11 wound around the stator core 12. The stator 10 is fixed in a state of being magnetically cut off to a motor case (not shown) via a connecting piece (not shown) made of a nonmagnetic material provided on the outer peripheral surface of the stator core 12. Thereby, generation | occurrence | production of the leakage magnetic flux etc. are suppressed, for example.

  As shown in FIGS. 2 and 3, the stator core 12 is formed with a plurality of stator teeth 13 protruding inward in the radial direction at predetermined intervals. Slots 14 that are groove-like spaces are formed between stator teeth 13 that are adjacent in the circumferential direction. The slot 14 constitutes a groove in the present invention. Here, the axial direction indicates a direction in which the rotating shaft 2 (see FIG. 5) of the rotor 20 extends. The radial direction is a direction orthogonal to the direction in which the rotating shaft 2 of the rotor 20 extends, and is indicated in the radial direction about the rotating shaft 2. The radially inward side indicates a side close to the rotating shaft 2 of the rotor 20 in the radial direction, and the radially outward side 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 slot 14 is formed in an isosceles trapezoidal shape when viewed from the axial direction of the rotating electrical machine 1. Specifically, the slot 14 is formed in an isosceles trapezoid shape that is convex outward in the radial direction, and the inner side in the radial direction is short and the outer side in the radial direction is long.

  The armature coil 11 is toroidally wound in a slot 14 formed between adjacent stator teeth 13 in 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 slot 14 by concentrated winding. The toroidal winding is a method in which the winding of the armature coil 11 is wound around the stator core 12 by rotating around the inner ring and the outer ring of the stator core 12 alternately.

  The armature coil 11 is a rectangular wire having a rectangular cross section, and is wound around the slot 14 in a toroidal winding state by edgewise winding. Edgewise winding is a method of winding a rectangular wire vertically with the short side of the rectangular wire facing the slot 14 inward and outward in the radial direction of the rotating electrical machine 1.

  Thereby, since the rectangular wires adjacent in the winding pitch direction are in surface contact with the long sides, the number of turns can be increased while maintaining the cross-sectional area corresponding to the current. For this reason, the space factor of the armature coil 11 can be improved, and the magnetomotive force of the stator 10 can be increased.

  The stator teeth 13 include a side surface portion 13 a that protrudes on one side and the other side in the axial direction of the stator core 12, and an inner surface portion 13 b that protrudes inward in the radial direction of the stator core 12. A first rotor tooth 212 (described later) is opposed to the side surface portion 13a of the stator tooth 13 in the axial direction. A second rotor tooth 222, which will be described later, faces the inner surface portion 13b of the stator tooth 13 in the radial direction.

  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.

  Specifically, the armature coils 11 are arranged on both sides in the circumferential direction of the stator teeth 13, and the pair of armature coils 11 includes a magnetic flux generated from one armature coil 11 and the other armature. The winding direction and energization direction are set so that the magnetic flux generated from the coil 11 is opposite in the circumferential direction.

  Thus, for example, when one armature coil 11 is in the V + phase and the other armature coil 11 is in the V− phase, the magnetic flux generated from the pair of armature coils 11 is sandwiched between the pair of armature coils 11. This occurs toward the stator teeth 13 so as to collide with the stator teeth 13. Then, the magnetic flux generated in the stator teeth 13 changes its direction in the direction orthogonal to the circumferential direction of the stator core 12 and travels from the stator teeth 13 to the rotor 20.

  A part of the magnetic flux directed to the rotor 20 passes through a rotor core 221 described later, and then proceeds to the stator teeth 13 sandwiched between the pair of armature coils 11 of the W + phase and the W− phase. Further, part of the magnetic flux directed toward the rotor 20 passes through a rotor core 221 described later, and then travels toward the stator teeth 13 sandwiched between the pair of armature coils 11 of the U + phase and the U− phase.

  Thus, on the surface where the stator teeth 13 and the rotor 20 face each other, a magnetic circuit for the magnetic flux (main magnetic flux) generated in the armature coil 11 is configured. The rotating electrical machine 1 rotates the rotor 20 with the surface where the stator teeth 13 and the rotor 20 face each other as a torque generation surface.

  Further, as described above, the stator 10 has the armature coil 11 in a toroidal winding and a concentrated winding. 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. That is, a harmonic component is superimposed on the magnetic flux generated in the stator 10. 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). In other words, the harmonic component is a second-order spatial harmonic when observed in a stationary coordinate system, and a third-order spatial harmonic when observed in a synchronous rotating coordinate system.

(Rotor)
As shown in FIG. 1, the rotor 20 includes a pair of axial gap rotors 210 arranged so as to sandwich the stator 10 in the axial direction, and a radial gap rotor 220 arranged on the radially inner side of the stator core 12. It consists of

  The pair of axial gap rotors 210 and radial gap rotors 220 are fixed so as to be integrally rotatable with respect to the rotating shaft 2 (see FIG. 5) so as to rotate in synchronization with each other. The pair of axial gap rotors 210 and the radial gap rotor 220 may be integrated.

  Each of the pair of axial gap rotors 210 includes a first rotor tooth 212 made of a magnetic material having a high magnetic permeability and an induction coil 215. The first rotor teeth 212 protrude in the axial direction toward the stator 10 side, and a plurality of first rotor teeth 212 are provided separately from each other at a predetermined interval in the circumferential direction. The first rotor teeth 212 have a role as a core around which the induction coil 215 is wound to form a magnetic path.

  The first rotor teeth 212 are fixed to the rotary shaft 2 (see FIG. 5) so as to be integrally rotatable via a fixing member (not shown) made of a nonmagnetic material such as resin. Thus, since the plurality of first rotor teeth 212 are not connected to each other by the back yoke, the plurality of first rotor teeth 212 are magnetically separated from each other. That is, the plurality of first rotor teeth 212 are configured in a so-called segment structure. For this reason, the main magnetic flux generated on the stator 10 side is not allowed to pass through the first rotor teeth 212, but only the harmonic component magnetic flux can be passed.

  Since the first rotor teeth 212 has a segment structure, the area where the magnetic flux links can be minimized. For this reason, generation | occurrence | production of the iron loss when a magnetic flux is linked to the 1st rotor teeth 212 from the stator 10 side can be reduced.

  In addition, since the first rotor teeth 212 has a segment structure, the first rotor teeth 212 forms a magnetic path of only the second-order spatial harmonics and does not form a magnetic path of the main magnetic flux. For this reason, generation | occurrence | production of the drag torque (brake torque) when the main magnetic flux passes between the stator teeth 13 and the side surface part 13a of the stator teeth 13 can be significantly reduced.

  Here, the ratio of the number of the side surface parts 13a of the stator teeth 13 and the number of the first rotor teeth 212 is 3: 2. Thereby, the second-order spatial harmonics can be most efficiently utilized as field energy.

  The first rotor teeth 212 are configured to face the stator teeth 13 on both sides in the axial direction of the stator core 12, that is, on one side and the other side in the axial direction of the stator core 12.

  An induction coil 215 is wound around the first rotor teeth 212 so as to form a layer in the axial direction. The induction coil 215 includes a winding coated with an insulating material.

  The induction coil 215 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 215. Thereby, the induction coil 215 induces an induced current.

  In the present embodiment, the first rotor teeth 212 are formed in an isosceles trapezoidal shape when viewed from the axial direction of the rotating electrical machine 1 (see FIG. 3). Specifically, the first rotor teeth 212 are formed in the shape of an isosceles trapezoid whose inner side in the radial direction is shorter than the outer side in the radial direction. The bottom) is short and the radially outer side (bottom bottom) is long.

  The stator core 12 has a slot 14 having the same shape as the first rotor teeth 212 between the side surface portions 13a of the adjacent stator teeth 13. That is, the first rotor teeth 212 is formed in the same isosceles trapezoid shape as the slot 14.

  For this reason, the shape of the side surface portion 13a of the stator teeth 13 is also a shape obtained by inverting the same isosceles trapezoid as that of the slot 14 in the radial direction, that is, a shape symmetrical to the slot 14 in the radial direction. The side surface portion 13a is formed in the shape of an isosceles trapezoid whose outer side in the radial direction is shorter than the inner side in the radial direction, and the outer side (upper base) in the radial direction is short. The inner side (bottom base) is long.

  Thereby, when the rotor 20 rotates and the side surface portion 13a and the first rotor teeth 212 pass each other in a face-to-face state, the side of the trapezoidal leg of the side surface portion 13a and the side of the trapezoidal leg of the first rotor teeth 212 However, they will pass each other in parallel. In other words, when the rotor 20 rotates, the trapezoidal first rotor teeth 212 are simultaneously and simultaneously overlapped with each other on the radially outer side and the inner side with respect to the trapezoidal side surface portion 13a of the stator teeth 13. It will pass each other. Thereby, the drag torque (brake torque) generated between the side surface portion 13a of the stator teeth 13 and the first rotor teeth 212 can be reduced to the minimum. Further, since the pulsation of the inductance is maximized, the amplitude of the second-order spatial harmonics linked to the first rotor teeth 212 can be maximized, and the induced electromotive force generated in the induction coil 215 can be increased.

  In the present embodiment, the first rotor teeth 212 and the slot 14 are both formed in a trapezoidal shape, but may be in the same shape as each other and are not limited to the trapezoidal shape.

  The radial gap rotor 220 includes a rotor core 221 made of a magnetic material having a high magnetic permeability and fixed so as to be integrally rotatable with respect to the rotating shaft 2 (see FIG. 5), a permanent magnet 223, and a magnetic path member 225.

  The rotor core 221 is formed with a plurality of second rotor teeth 222 projecting from the rotor core 221 outward in the radial direction at predetermined intervals along the circumferential direction of the rotor core 221.

  The second rotor teeth 222 are opposed to the stator teeth 13 on the radially inner side of the stator core 12. A permanent magnet 223 is disposed on the second rotor teeth 222.

  The permanent magnet 223 is composed of, for example, a neodymium magnet (Nd—Fe—B magnet), and is included in the second rotor teeth 222.

  The magnetic path member 225 guides a part of the magnetic flux of the permanent magnet 223 and is formed in an annular shape around the permanent magnet 223. Specifically, the magnetic path member 225 guides a magnetic flux that leaks in the axial direction of the rotor core 221 from the permanent magnet 223 out of the magnetic flux generated by the permanent magnet 223 (hereinafter, this magnetic flux is referred to as “leakage magnetic flux”). .

  The magnetic path member 225 includes an inner packet part 225 a included in the second rotor teeth 222 together with the permanent magnet 223, and an extending part 225 b extended from the second rotor teeth 222 so as to protrude in the axial direction of the rotor core 221. ing. In the magnetic path member 225, the extending portion 225b is formed in such a shape that a portion of the permanent magnet 223 located on the side surface 223a side in the axial direction extends from the second rotor tooth 222 in the axial direction.

  The inner packet part 225a is arranged on the inner side and the outer side in the radial direction of the permanent magnet 223 so as to sandwich the permanent magnet 223 in the radial direction. The inner packet part 225 a is configured to pass a magnetic flux interlinking from the permanent magnet 223 to the stator 10. The inner packet part 225a is formed of, for example, a dust core in which a fine powder of a ferromagnetic material is compressed and hardened.

  The extending portions 225b correspond to portions extending in the axial direction from the second rotor teeth 222 of the magnetic path member 225, and are provided on both sides of the second rotor teeth 222 in the axial direction via regions of high magnetic resistance. It has been.

  The extending portion 225b is formed in a U shape by a dust core in which a fine powder of a ferromagnetic material is compressed and hardened, for example. The extending portion 225b is disposed such that each end surface on the second rotor teeth 222 side faces the end surface in the axial direction of each inner packet portion 225a. Moreover, the extending | stretching part 225b is arrange | positioned so that the end surface of each inner packet part 225a in the both sides of an axial direction may be opposed.

  The extending portion 225b is configured as a separate body from the inner packet portion 225a, and is held by the rotor core 221 or other member via a connecting member (not shown). Thereby, the inner packet part 225 a and the extending part 225 b are separated in the axial direction of the rotor core 221.

  Further, a gap G (see FIG. 5) having a predetermined size is formed between the end surfaces on both sides in the axial direction of the inner packet part 225a and the end surface on the second rotor teeth 222 side of the extending part 225b. This gap G is formed as a high magnetic resistance region. The gap G is such that when a direct current is not supplied to the variable field coil 226 described later, the leakage magnetic flux of the permanent magnet 223 does not flow from the inclusion part 225a to the extension part 225b, or even if it flows, the gap G becomes very small. It is a size. Further, the gap G is set to such a size that leakage flux of the permanent magnet 223 flows from the inner packet part 225a to the extension part 225b when a direct current is supplied to the variable field coil 226 described later.

  A variable field coil 226 is wound around the extending portion 225b along the circumferential direction of the rotor core 221. The variable field coil 226 is a coil that functions so that the amount of leakage flux guided from the permanent magnet 223 to the magnetic path member 225 can be adjusted according to the magnitude of the induced current generated in the induction coil 215. That is, the variable field coil 226 short-circuits the inside of the magnetic path member 225 and guides the leakage magnetic flux of the permanent magnet 223 to the magnetic path member 225, thereby reducing the amount of magnetic flux of the permanent magnet 24 linked from the rotor 20 to the stator 10. Adjustable coil.

  The variable field coil 226 is wound around the extending portion 225b of the magnetic path member 225 so that the leakage flux of the permanent magnet 223 flows in a direction (direction indicated by an arrow in FIG. 6) guided by the magnetic path member 225. ing. More specifically, the variable field coil 226 induces a magnetic flux (hereinafter referred to as an “inductive magnetic flux”) that induces the leakage magnetic flux of the permanent magnet 223 in a direction in which the magnetic flux is short-circuited in the magnetic path member 225 (direction indicated by an arrow in FIG. Is wound around the extending portion 225b.

  Thereby, the variable field coil 226 generates an induced magnetic flux by being supplied with a direct current rectified by a rectifier circuit 30 to be described later, and as shown in FIG. 6, the magnetic path of the leakage magnetic flux of the permanent magnet 223 A short circuit in the member 225 is assisted. By adjusting the magnetic flux amount of the induced magnetic flux, the magnetic flux amount of the leakage magnetic flux of the permanent magnet 223 that short-circuits the magnetic path member 225 is adjusted.

  The amount of induced magnetic flux increases as the direct current supplied to the variable field coil 226 increases and the number of turns of the variable field coil 226 increases. The number of turns of the variable field coil 226 is set to the number of turns obtained experimentally in advance.

  The direct current supplied to the variable field coil 226 is varied according to the magnitude of the induced current generated in the induction coil 215. Thereby, the magnetic flux amount of the leakage magnetic flux of the permanent magnet 223 that short-circuits the magnetic path member 225 is adjusted according to the magnitude of the induced current generated in the induction coil 215. The induced current generated in the induction coil 215 increases as the rotational speed of the rotor 20 increases. Therefore, the magnetic flux amount of the leakage magnetic flux of the permanent magnet 223 that short-circuits the inside of the magnetic path member 225 increases as the rotor 20 rotational speed increases.

(Rectifier circuit)
The rotating electrical machine 1 also includes a rectifier circuit 30 that rectifies the induced current generated in the induction coil 215 and supplies the rectified current to the variable field coil 226.

  As shown in FIG. 4, the rectifier circuit 30 includes two diodes D1 and D2 as rectifier elements, and is a closed circuit in which the diodes D1 and D2 are connected to the two induction coils 215 and the two variable field coils 226. It is configured. The rectifier circuit 30 is provided on one side and the other side in the axial direction of the rotor 20 so as to correspond to the induction coil 215 and the variable field coil 226 on one side and the other side in the axial direction of the rotor 20, respectively.

  The two induction coils 215 in the rectifier circuit 30 are induction coils 215 adjacent in the circumferential direction of the axial gap rotor 210. The two variable field coils 226 are the variable field coils 226 that are adjacent to each other in the circumferential direction of the radial gap rotor 220.

  For example, the diodes D1 and D2 are provided in the axial gap rotor 210 or the radial gap rotor 220 in a state of being housed in a diode case (not shown). The diodes D1 and D2 may be mounted inside the axial gap rotor 210 or the radial gap rotor 220.

  In the rectifier circuit 30, the AC induced current generated in the two induction coils 215 is rectified by the diodes D 1 and D 2, and the rectified DC current is supplied to the two variable field coils 226 connected in series. Supplied as The two variable field coils 226 generate an induced magnetic flux when supplied with a direct current.

(Operation of rotating electrical machine)
Next, with reference to FIG.5 and FIG.6, the effect | action of the rotary electric machine 1 which concerns on this Embodiment is demonstrated.

  As described above, rotating electrical machine 1 according to the present embodiment is a permanent magnet type synchronous motor that includes permanent magnet 223 in rotor 20 and outputs torque using the magnetic flux of permanent magnet 223.

  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 passed to generate a magnetic flux in a direction that cancels the magnetic flux of the permanent magnet. For this reason, useless energy is consumed with respect to the output, resulting in 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.

  Further, when a neodymium magnet is used as the permanent magnet, an eddy current is generated in the permanent magnet due to the fluctuation of the external magnetic field by the 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 linked from the permanent magnet 223 to the stator 10 is adjusted by the action of the magnetic path member 225 and the variable field coil 226 described above without performing field weakening control. Possible 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 226 does not generate an induced magnetic flux or a minute amount even if it is generated. Therefore, the magnetic resistance is high in the gap G.

  As a result, as shown in FIG. 5, the leakage magnetic flux of the permanent magnet 223 does not short-circuit the magnetic path member 225. Thereby, all of the magnetic flux of the permanent magnet 223 is linked to the stator 10.

  Thus, when the rotational speed of the rotor 20 is low, the amount of magnetic flux interlinked from the permanent magnet 223 to the stator 10 can be increased compared to when the rotational speed of the rotor 20 is high.

(At high rotor speed)
On the other hand, when the rotational speed of the rotor 20 is high in the rotating electrical machine 1 according to the present embodiment, 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 20 increases.

  As a result, an induced current is induced in the induction coil 215 of the axial gap rotor 210, and the induced current is rectified by the rectifier circuit 30 and supplied to the variable field coil 226 as a direct current.

  The variable field coil 226 supplied with the direct current generates an induced magnetic flux in a direction in which the leakage magnetic flux of the permanent magnet 223 shorts the magnetic path member 225. Thereby, the magnetic resistance in the gap G decreases.

  As a result, as shown in FIG. 6, a part of the magnetic flux of the permanent magnet 223 short-circuits the magnetic path member 225 as a leakage magnetic flux. Thereby, the magnetic flux excluding the leakage magnetic flux among the magnetic fluxes of the permanent magnet 223 is linked to the stator 10. That is, the amount of magnetic flux interlinked from the permanent magnet 223 to the stator 10 is suppressed.

  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.

  Furthermore, 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.

  As described above, in the rotating electrical machine 1 according to the present embodiment, the amount of magnetic flux interlinked from the permanent magnet 223 to the stator 10 can be adjusted without performing field-weakening control. Therefore, when the rotational speed of the rotor 20 is high, the efficiency is improved. A decrease can be prevented. Further, the output can be improved when the rotational speed of the rotor 20 is low.

(Current phase control of armature coil)
In order to increase the leakage magnetic flux and further suppress the amount of magnetic flux linked to the stator 10 from the permanent magnet 223, as shown in FIG. 7, a vector of current supplied to the armature coil 11 (hereinafter referred to as the armature current). (Also referred to as a vector) is preferably retarded in the + d-axis direction.

  In FIG. 7, the direction of the magnetic pole of the permanent magnet 223 is defined as the d-axis, and the interval between the magnetic poles is defined as the q-axis. Further, the −d axis direction (the direction facing the magnetic pole of the permanent magnet 223) is the advance side (weakening field region), and the + d axis direction (the forward direction side of the permanent magnet 223 magnetic pole) is the retarding side (strong field). Area).

  As shown in FIG. 7, by retarding the phase of the armature current vector β in the + d-axis direction, the magnetic path member 225 can be short-circuited with more magnetic flux from the permanent magnet 223 as leakage flux. Thereby, the magnetic flux amount of the magnetic flux linked to the stator 10 from the permanent magnet 223 can be further suppressed.

  Further, by retarding the phase of the armature current vector β in the + d-axis direction, the magnetic flux from the stator 10 is linked in the forward direction with respect to the magnetic flux of the permanent magnet 223. For this reason, the demagnetization countermeasure of the permanent magnet 223 can be made easy, a low-cost magnet can be adopted, and the heat generation countermeasure of the magnet can be facilitated.

  In FIG. 8, the vertical axis represents the voltage across the armature coil 11, that is, the induced electromotive force in the reverse direction, and the horizontal axis represents the phase of the armature current vector β (referred to as current phase in the figure). In the phase shown on the horizontal axis, the right side from 0 is the advance side (−d axis direction, field weakening region), and the left side from 0 is the retarding side (+ d axis direction, field strengthening region). In FIG. 8, in the case of the configuration of the present invention in which a circuit including the induction coil 215 and the variable field coil 226 for controlling the leakage magnetic flux is provided (in the drawing, it is indicated that there is a rotor circuit), this circuit is The voltage between the terminals of the armature coil 11 in the case of a comparative example not provided (denoted as “no rotor circuit” in the figure) is shown. As shown in FIG. 8, when there is a rotor circuit, the voltage between terminals is lowered by retarding the phase of the armature current vector β in the + d-axis direction (left direction) compared to the case without the rotor circuit. Can do.

  As described above, according to the rotating electrical machine 1 of the present embodiment, an induction current is generated in the induction coil 215 of the axial gap rotor 210 based on the harmonic component superimposed on the magnetic flux generated on the stator 10 side. The induced current is rectified by the rectifier circuit 30 and supplied to the variable field coil 226. Thereby, the magnetic flux quantity of the leakage magnetic flux of the permanent magnet 223 which short-circuits the inside of the magnetic path member 225 can be adjusted.

  The harmonic component superimposed on the magnetic flux generated on the stator 10 side is obtained by supplying three-phase alternating current to the armature coil 11 that is toroidally wound and concentratedly wound on the stator 10. For this reason, in order to generate the direct current supplied to the variable field coil 226, a special device such as a DC / DC converter is not required.

  Thus, the rotating electrical machine 1 of the present embodiment adjusts the amount of magnetic flux interlinked from the permanent magnet 223 to the stator 10 with a simple configuration without using a special device such as a DC / DC converter. be able to. As a result, the rotating electrical machine 1 of the present embodiment can vary the magnetic flux of the permanent magnet 223 with a low-cost configuration.

  Further, since the stator core 12 has the slot 14 having the same shape as that of the first rotor teeth 212 between the adjacent stator teeth 13, the side surface portion 13 a of the stator teeth 13 and the first rotor teeth 212 when the rotor 20 rotates. The width in the circumferential direction of the area facing each other can be changed while maintaining the state where the outer side and the inner side in the radial direction are equal. Accordingly, the amount of magnetic flux interlinked on the outer side in the radial direction and the amount of magnetic flux interlinked on the inner side in the radial direction can be equalized, and thus occurrence of surface vibration can be prevented. Further, while preventing a decrease in torque due to a drag torque generated between the side surface portion 13a of the stator teeth 13 and the first rotor teeth 212, second-order spatial harmonics serving as energy for controlling leakage magnetic flux are changed to the stator. The variable field coil 226 of the rotor 20 can be supplied without contact from the 10 side. In addition, since the pulsation of the inductance is maximized, the amplitude of the second-order spatial harmonics linked to the first rotor teeth 212 can be maximized, and the induced electromotive force generated in the induction coil 215 can be increased. Become.

  The rotating electrical machine 1 can be suitably employed as, for example, a vehicle-mounted motor, a wind power generator, or a machine tool motor.

  In the present embodiment, the first rotor teeth 212 are provided so as to face both axial sides of the stator core 12. However, the present invention is not limited to this, and for example, the side surface on one axial side of the stator core 12 is provided. Alternatively, it may be provided to face the other side surface. That is, the first rotor teeth 212 may be configured to be provided only on one of the side surfaces on the one side and the other side surface in the axial direction of the stator core 12. In this case, the physique of the rotary electric machine 1 can be made smaller by adopting only the axial gap rotor 210 on one side in the axial direction.

  The rotating electrical machine 1 of the present embodiment can also be applied to a double rotor type rotating electrical machine that includes two rotors, an outer rotor and an inner rotor, on the inner side in the radial direction of the stator. In this case, the armature coil is concentratedly wound around the stator, but toroidal winding is not adopted. Further, in this double rotor type rotating electrical machine, an induction coil is disposed in the outer rotor, and a permanent magnet, a magnetic path member, and a variable field coil are disposed in the inner rotor. Note that the configurations of the outer rotor and the inner rotor described above may be reversed.

  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 Rotating electric machine 2 Rotating shaft 10 Stator 11 Armature coil 12 Stator core 13 Stator teeth 13a Side surface part 13b Inner surface part 14 Slot (groove part)
20 rotor 30 rectifier circuit 210 axial gap rotor 212 first rotor teeth 215 induction coil 220 radial gap rotor 221 rotor core 222 second rotor teeth 223 permanent magnet 225 magnetic path member 225a inner part 225b extending part 226 variable field coil D1, D2 diode

Claims (4)

A rotating electric machine comprising a stator having an armature coil and a rotor having a permanent magnet,
The stator is
An annular stator core having a plurality of stator teeth arranged at predetermined intervals in the circumferential direction;
An armature coil wound toroidally between the adjacent stator teeth,
The rotor is
A first rotor tooth facing the stator teeth on at least one surface in the axial direction of the stator core;
A second rotor tooth facing the stator teeth on the radially inner side of the stator core;
An induction coil wound around the first rotor teeth and generating an induced current based on magnetic flux generated on the stator side;
A permanent magnet disposed on the second rotor teeth;
A magnetic path member disposed around the permanent magnet and guiding a part of the magnetic flux of the permanent magnet;
A variable field coil provided on the magnetic path member and capable of adjusting a magnetic flux amount of a magnetic flux guided to the magnetic path member based on an induced current generated in the induction coil;
The stator core has a groove portion having the same shape as the first rotor teeth between the adjacent stator teeth.   The rotating electric machine according to claim 1, wherein the armature coil is toroidally wound in the groove portion of the stator.   The rotating electrical machine according to claim 1 or 2, wherein a plurality of the first rotor teeth are provided separately from each other at a predetermined interval in the circumferential direction.   4. The rotating electrical machine according to claim 1, wherein the rotor includes the first rotor teeth on both sides in the axial direction of the stator core. 5.

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