JP6661960B2 - Self-starting permanent magnet motor - Google Patents

Description

  The present invention relates to a self-starting permanent magnet type electric motor including a stator on which an exciting coil is wound, and a rotor which is rotatably opposed to the stator with a predetermined gap.

One type of motor that has become widespread as an AC motor is a cage-type three-phase induction motor.
The cage-type three-phase induction motor applies a three-phase alternating current to the stator windings to generate a rotating magnetic field, thereby forming a secondary conductor consisting of a metal bar and a metal end ring placed on the rotor. The electric motor generates an induced current and generates torque by an interaction between the induced current and the rotating magnetic field.
One of the features of the squirrel-cage three-phase induction motor is that it can be started only by directly connecting to an AC power supply without performing control by an inverter.

  On the other hand, in recent years, permanent magnet type electric motors that have become widespread in response to demands for higher efficiency and smaller size are composed of a rotating magnetic field generated by applying a three-phase alternating current to a stator winding and a permanent magnet generated from the rotor. This is an electric motor mainly using magnet torque generated by interaction with magnetic flux. Permanent magnet motors have the characteristics of higher efficiency and smaller size than squirrel-cage three-phase induction motors, but can generate torque only at synchronous speed, so they must be started unless controlled by an inverter. Can not.

As a method for solving such a problem of the permanent magnet electric motor, a self-starting permanent magnet electric motor is known as described in Patent Document 1 and the like.
The self-starting type permanent magnet electric motor disclosed in Patent Literature 1 has a plurality of slots in a rotor and a conductive bar disposed in a slot, for example, for an interior permanent magnet type electric motor of an embedded magnet type. This motor is also provided with a function as an induction motor by being connected to an end ring.
The self-starting type permanent magnet electric motor disclosed in Patent Document 1 operates as an induction motor utilizing the interaction between the induced current and the rotating magnetic field during asynchronous operation from the time of starting to the time of being pulled into the synchronous speed. After that, it acts as a permanent magnet type electric motor using magnet torque. Therefore, there is a feature that self-starting is possible without using an inverter and high-efficiency operation is possible at a synchronous speed.

JP 2009-153356 A

By the way, the self-starting permanent magnet electric motor disclosed in Patent Document 1 has a conductive bar and a conductive end ring which are unnecessary when operating at a synchronous speed. Since an eddy current flows due to the magnetic flux, there is a problem that the efficiency is not as high as that of a normal permanent magnet motor when operating at a synchronous speed.
It also has slots, conductive bars, and conductive end rings required for the rotor of the cage type three-phase induction motor, and also has the permanent magnets required for the rotor of the permanent magnet type motor. Therefore, when viewed as a single motor, the number of parts and the number of manufacturing steps are larger than those of the cage type three-phase induction motor or the permanent magnet type motor, which causes an increase in cost.
Therefore, the present invention has been made to solve this conventional problem, and an object of the present invention is to achieve high efficiency with a small size, and to reduce the number of parts and the number of manufacturing steps to reduce the cost. It is an object of the present invention to provide a self-starting permanent magnet type electric motor which can be used.

  In order to achieve the above object, a self-starting permanent magnet electric motor according to one aspect of the present invention includes a stator on which an exciting coil is wound, and a stator and a predetermined gap provided to face and rotate freely. The rotor comprises a cylindrical rotor core, a plurality of rotor cores provided at predetermined circumferential intervals on the outer diameter side of the rotor core, and extending in the rotational axis direction. Bar slots, a plurality of conductive permanent magnet bars made of conductive permanent magnets embedded in the plurality of bar slots, and a pair of end rings connected to both ends of the plurality of conductive permanent magnet bars. , Is provided.

  ADVANTAGE OF THE INVENTION According to the self-starting type permanent magnet electric motor which concerns on this invention, while being compact and realizing high efficiency, the number of parts and the number of manufacturing steps are small, and cost reduction can be achieved.

It is a sectional view showing the schematic structure of the self-starting permanent magnet type electric motor concerning a 1st embodiment concerning the present invention. It is a figure showing the outline of the conductive permanent magnet bar and end ring which constitute the self-starting permanent magnet type electric motor concerning the present invention. It is a figure showing the rotor which constitutes the self-starting permanent magnet type electric motor of a 1st embodiment concerning the present invention. It is a figure showing a rotor which constitutes a self-starting permanent magnet type electric motor of a 2nd embodiment concerning the present invention. It is a figure showing a rotor which constitutes a self-starting permanent magnet type electric motor of a 3rd embodiment concerning the present invention. It is the figure which expanded and showed the upper right side of the rotor in FIG. It is a graph which shows the magnetomotive force waveform in the self-starting permanent-magnet type electric motor of 3rd Embodiment concerning this invention compared with a conventional apparatus. It is a figure showing a rotor which constitutes a self-starting permanent magnet type electric motor of a 4th embodiment concerning the present invention. FIG. 9 is an enlarged view of the upper right side of the rotor in FIG. 8.

Next, first to third embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the plane dimension, the ratio of the thickness of each layer, and the like are different from actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. In addition, it goes without saying that parts having different dimensional relationships and ratios are included between the drawings.
The first to third embodiments described below exemplify an apparatus and a method for embodying the technical idea of the present invention. The shape, structure, arrangement, etc. are not specified as follows. The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims.

[Self-Starting Permanent Magnet Motor of First Embodiment]
FIG. 1 shows a self-starting permanent magnet motor 1 according to a first embodiment of the present invention. The self-starting permanent magnet motor 1 is a 4-pole, 24-slot interior magnet synchronous motor. It should be noted that the present invention is not limited at all by the number of poles, the number of slots, the dimensions of other parts, and the like.
As shown in FIG. 1, a self-starting permanent magnet electric motor 1 includes a cylindrical frame 2, a stator 10 disposed on the inner peripheral side of the cylindrical frame 2, and an inner peripheral side of the stator 10. And a rotator 20 that is rotatably arranged opposite to and separated by a predetermined gap G.
The stator 10 includes a cylindrical stator core 11, and 24 slots 12 and 24 magnetic pole teeth 13 formed at equal intervals in the circumferential direction on the inner peripheral surface side of the stator core 11. I have. An excitation coil 14 wound in the slot 12 is wound around each magnetic pole tooth 13.

As shown in FIGS. 1 and 3, the rotor 20 has a cylindrical rotor core 21 formed by laminating non-oriented electromagnetic steel sheets, and four magnet slots formed on the inner diameter side of the rotor core 21. 22, four permanent magnets 23 embedded in the magnet slots 22, a plurality of bar slots 24 formed at equal intervals in the circumferential direction on the outer diameter side of the rotor core 21, and embedded in the plurality of bar slots 24. And a plurality of conductive bars 25.
The rotor 20 is rotated by the rotation shaft 3 fitted and fixed to the center of the rotor core 21.
The four magnet slots 22 are formed in the inner diameter side of the rotor core 21 so as to penetrate to both ends in the axial direction, and are elongated rectangular holes extending linearly. In these magnet slots 22, permanent magnets 23 having a rectangular cross section having a size smaller than the size of each magnet slot 22 are embedded and fixed by an adhesive or the like. By embedding the permanent magnets 23 in these four magnet slots 22, four magnetic poles 26 are provided.

As the material of the permanent magnet 23, a neodymium sintered magnet, a ferrite magnet, an alnico magnet, or the like is used.
The plurality of conductive bars 25 disposed inside the plurality of bar slots 24 formed on the outer diameter side of the rotor core 21 are connected at one end of the plurality of conductive bars 25 as shown in FIG. One end-side conductive end ring 27 and the other end-side conductive end ring 28 connected to the other ends of the plurality of conductive bars 25 constitute a cage conductor 29.
The plurality of bar slots 24 formed at equal intervals in the circumferential direction on the outer diameter side of the rotor core 21 are formed to penetrate to both ends of the rotor core 21 in the axial direction. , A plurality of bar slots 24 are inserted therein, and one end side conductive end ring 27 connected to one end of the plurality of bar slots 24 is connected to the other end side conductive end ring 28 connected to the other end of the plurality of bar slots 24. Is disposed at the other axial end of the rotor core 21.

Here, the plurality of conductive bars 25 are formed of permanent magnets (hereinafter, referred to as conductive permanent magnet bars 25). The N and S poles of the plurality of conductive permanent magnet bars 25 are magnetized so that the magnetic flux density of each of the permanent magnets 23 constituting the four magnetic poles 26 increases. As a material of the conductive permanent magnet bar 25, an alnico magnet is used.
As the material of the one end side conductive end ring 27 and the other end side conductive end ring 28 constituting the cage conductor 29, a material having high conductivity such as copper or aluminum is used.
The bar slot according to the present invention corresponds to the bar slot 24, the conductive permanent magnet bar according to the present invention corresponds to the conductive permanent magnet bar 25, and the pair of end rings according to the present invention The magnet slot according to the present invention corresponds to the magnet slot 22, and the permanent magnet according to the present invention corresponds to the permanent magnet 23, corresponding to the conductive end ring 27 and the other end side conductive end ring 28.

Next, the operation of the self-starting permanent magnet electric motor 1 according to the first embodiment will be described.
When the self-starting permanent magnet motor 1 is started, AC power is applied to the exciting coil 14 of the stator 10. The exciting coil 14 to which the current is applied generates a rotating magnetic field due to the magnetomotive force. Thereby, torque is generated by interaction with the induction current generated in the cage conductor 29 of the rotor 20, and the rotor 20 rotates as an induction motor.
When the rotor 20 is accelerated to near the synchronous speed of the rotating magnetic field of the stator 10, the magnetomotive force generated by the permanent magnets 23 constituting the four magnetic poles 26 of the rotor 20 causes the exciting coil 14 of the stator 10 to rotate. Is generated by the rotating magnetic field at the synchronous speed generated by the motor and generates torque, and the rotor 20 rotates as a synchronous machine.

Next, the operation and effect of the self-starting permanent magnet motor 1 of the first embodiment will be described.
The plurality of conductive permanent magnet bars 25 constituting the cage-shaped conductor 29 function as secondary conductors through which an induced current flows when the self-starting permanent magnet motor 1 starts, and the synchronous speed of the self-starting permanent magnet motor 1 increases. During the operation of, torque is generated by the magnetic flux generated by itself.
Therefore, when the self-starting type permanent magnet type electric motor 1 is operated at the synchronous speed, the torque of the self-starting type permanent magnet type electric motor 1 is increased by the torque of the magnetic flux generated by the plurality of conductive permanent magnet bars 25. When the same torque is required as in the case of the self-starting permanent magnet motor, the size of the self-starting permanent magnet motor 1 can be reduced, and the efficiency can be increased by reducing the current.
Further, the torque of the self-starting permanent magnet motor 1 can be increased by the magnetic flux generated by the plurality of conductive permanent magnet bars 25 without increasing the number of permanent magnets 23 embedded in the rotor core 21. In addition, the number of parts and manufacturing steps are reduced, and the manufacturing cost of the self-starting permanent magnet motor 1 can be reduced.

[Self-Starting Permanent Magnet Motor of Second Embodiment]
Next, FIG. 4 shows a rotor 30 constituting a self-starting permanent magnet type electric motor according to a second embodiment of the present invention.
The same components as those shown in FIGS. 1 to 3 are denoted by the same reference numerals, and description thereof is omitted.
The rotor 30 according to the second embodiment includes a cylindrical rotor core 21 formed by laminating non-oriented electromagnetic steel sheets, a rotating shaft 3 fitted and fixed to the center of the rotor core 21, A plurality of bar slots 24 formed at equal intervals in the circumferential direction on the outer diameter side of the daughter core 21; a plurality of conductive permanent magnet bars 25 disposed inside the plurality of bar slots 24; One end side conductive end ring 27 and the other end side conductive end ring 28 which are connected to one end and the other end of the magnet bar 25 and constitute a cage conductor 29 are provided.

However, the rotor 30 of the second embodiment does not have the magnetic poles 26 (the magnet slots 22 and the permanent magnets 23 embedded in the magnet slots 22) of the rotor 20 of the first embodiment.
When the self-starting permanent magnet type electric motor is started, AC power is applied to the exciting coil 14 of the stator 10. The exciting coil 14 to which the current is applied generates a rotating magnetic field due to the magnetomotive force. Thereby, torque is generated by interaction with the induction current generated in the cage conductor 29 of the rotor 30, and the rotor 30 rotates as an induction motor.
When the rotor 30 is accelerated to near the synchronous speed of the rotating magnetic field of the stator 10, the magnetomotive force generated by the plurality of conductive permanent magnet bars 25 forming the cage conductor 29 causes the exciting coil of the stator 10 to rotate. The rotor 20 is rotated as a synchronous machine by generating a torque by being drawn into the rotating magnetic field of the synchronous speed generated by the rotor 14.

In the second embodiment, the plurality of conductive permanent magnet bars 25 constituting the cage type conductor 29 function as secondary conductors through which an induced current flows when the self-starting permanent magnet type electric motor starts, and the self-starting permanent magnet type When the motor operates at the synchronous speed, torque is generated by the magnetic flux generated by itself.
Therefore, the self-starting permanent magnet electric motor including the rotor 30 of the second embodiment is the same as the magnetic pole 26 (the magnet slot 22 and the permanent magnet embedded in the magnet slot 22) used in the rotor 20 of the first embodiment. Since there is no magnet 23), the number of parts and the number of manufacturing steps are further reduced, and the manufacturing cost can be reduced.

[Self-Starting Permanent Magnet Motor of Third Embodiment]
Next, FIGS. 5 to 7 show a rotor 40 constituting a self-starting permanent magnet electric motor according to a third embodiment of the present invention.
The rotor 40 includes a cylindrical rotor core 21 formed by laminating non-directional electromagnetic steel sheets, a rotation shaft 3 fitted and fixed to the center of the rotor core 21, and an inner diameter of the rotor core 21. Four permanent magnets 23 embedded in these magnet slots 22, a plurality of bar slots 24 formed at equal intervals in the circumferential direction on the outer diameter side of the rotor core 21, A plurality of conductive permanent magnet bars 41, 42, 43, 44 arranged inside the plurality of bar slots 24 are connected to one end and the other end of the plurality of conductive permanent magnet bars 41, 42, 43, 44. , A cage-shaped conductor 29 is provided with one end side conductive end ring 27 and the other end side conductive end ring 28.

In FIG. 5, the central axes of the four permanent magnets 23 constituting the four magnetic poles 26 are d-axes, and the axis separated by an electrical angle of 90 ° from these d-axes is the q-axis.
The conductive permanent magnet bar 41 is buried in the bar slot 24 closest to the d-axis, the conductive permanent magnet bar 44 is buried in the bar slot 24 closest to the q-axis, and the bar slot between the d-axis and the q-axis. 24, conductive permanent magnet bars 42, 43 are embedded.
In FIG. 5, it is not shown that the conductive permanent magnet bars 41, 42, 43, and 44 are embedded in all the bar slots 24, but the conductive permanent magnets are provided in the bar slots 24 closest to the d-axis. The bar 41 is embedded, and the conductive permanent magnet bars 42, 43, 44 are embedded toward the bar slot 24 closest to the d-axis.

The conductive permanent magnet bar 41 is formed by laminating a conductive permanent magnet 41a of the same material, such as an alnico magnet, and a conductive nonmagnetic member 41b, such as copper or aluminum, in the cross-sectional direction. The other conductive permanent magnet bars 42, 43, 44 also include conductive permanent magnets 42a, 43a, 44a stacked in the cross-sectional direction, and conductive non-magnetic members 42b, 43b, 44b. .
The sectional ratio of the permanent magnet 41a to the non-magnetic member 41b of the conductive permanent magnet bar 41 closest to the d-axis (the sectional area of the permanent magnet 41a / the sectional area of the non-magnetic member 41b) is S1, and the conductive permanent magnet bar The sectional ratio of the permanent magnet 21a to the nonmagnetic member 43b of the conductive permanent magnet bar 43 is designated as S3, the sectional ratio of the permanent magnet 43a to the nonmagnetic member 43b of the conductive permanent magnet bar 43 is designated as S2, and the conductive permanent magnet bar 44 closest to the q-axis. Assuming that the sectional ratio of the conductive permanent magnet 44a to the nonmagnetic member 44b is S4, the sectional ratio of the conductive permanent magnet bars 41, 42, 43, and 44 from the d axis to the q axis decreases monotonically ( S1>S2>S3> S4).

In this way, the amount of magnet magnetic flux generated in the bar slot 24 monotonously decreases in the order from the bar slot 24 closest to the d-axis to the bar slot 24 closest to the q-axis.
5 and 6, the conductive permanent magnet bars 41, 42, 43, and 44 embedded in the bar slot 24 on the upper right outer periphery have been described. However, the d-axis and q-axis bar slots other than the upper right outer periphery are described. The conductive permanent magnet bar embedded in 24 has the same configuration.

FIG. 7 (a) shows an advantage that the magnetic flux amount generated in the bar slot 24 monotonously decreases in the order from the bar slot 24 closest to the d-axis to the bar slot 24 closest to the q-axis. ) And (b).
FIG. 7A shows that a plurality of conductive permanent magnet bars are not embedded in the circumferential direction on the outer diameter side of the rotor core 21 (in FIG. 5, the conductive permanent magnet bars 41, 42, 43, and 44 are embedded). 7 is a graph showing a magnetomotive force waveform of a rotor. FIG. 7B is a graph showing a magnetomotive force waveform of the rotor 40 shown in FIG.
7A and 7B, the angle θ is a rotation angle in the circumferential direction with reference to a predetermined position in the circumferential direction of the rotor 40.
First, a rotor having a magnetomotive force waveform shown in FIG. 7A generates a magnetic flux from a permanent magnet 23 embedded in a magnet slot 22 as shown in FIG. Is a rectangular wave shape indicated by the symbol A.

  On the other hand, when the amount of magnetic flux generated in the bar slot 24 is monotonously decreased in the order from the bar slot 24 closest to the d-axis to the bar slot 24 closest to the q-axis, the permanent magnet 23 Magnetic flux is generated not only from the conductive permanent magnet bars 41, 42, 43, and 44, but also the waveform of the magnetomotive force generated by the magnetic flux from the permanent magnet 23 and the conductive permanent magnet bars 41, 42, 43, and 44 is shown in FIG. As shown in FIG. 7 (b), the magnetic flux of the conductive permanent magnet bars 41, 42, 43, and 44 forms on the upper side and both sides of the rectangular wave shape indicated by the symbol A generated by the magnetic flux of the permanent magnet 23, and is indicated by the symbol B. The shape becomes a shape obtained by adding a gradually decreasing step-like waveform or a gradually increasing step-like waveform indicated by reference symbol C.

That is, the waveform of the magnetomotive force generated by the magnetic flux from the permanent magnet 23 and the conductive permanent magnet bars 41, 42, 43, and 44 approaches a sine wave shape.
As described above, when the waveform of the magnetomotive force generated by the magnetic flux from the permanent magnet 23 and the conductive permanent magnet bars 41, 42, 43, and 44 approaches a sine wave shape, the fundamental component of the magnetomotive force increases and the harmonics increase. The components decrease. An increase in the fundamental wave component increases the torque, and a decrease in the harmonic wave component reduces the cogging torque and the torque ripple.
Therefore, as in the third embodiment, the amount of magnet magnetic flux generated in the bar slot 24 monotonously decreases in the order from the bar slot 24 closest to the d-axis to the bar slot 24 closest to the q-axis. In addition, it is possible to increase the torque and sufficiently reduce the cogging torque and the torque ripple.

Further, even when the self-starting permanent magnet type electric motor of the third embodiment is operated at the synchronous speed, the self-starting type permanent magnet type motor is controlled by the magnetic flux generated by the plurality of conductive permanent magnet bars 41, 42, 43, 44. Since the torque of the motor increases, when the same torque is required as in the case of the conventional self-starting permanent magnet motor, the size of the self-starting permanent magnet motor can be reduced and the current can be reduced. High efficiency can be achieved.
Furthermore, the magnetic flux generated by the plurality of conductive permanent magnet bars 41, 42, 43, 44 increases the torque of the self-starting permanent magnet motor without increasing the number of permanent magnets 23 embedded in the rotor core 21. Therefore, the number of parts and the manufacturing process can be reduced, and the manufacturing cost of the self-starting permanent magnet electric motor can be reduced.

[Self-Starting Permanent Magnet Motor of Fourth Embodiment]
Next, FIGS. 8 and 9 show a rotor 50 constituting a self-starting permanent magnet electric motor according to a fourth embodiment of the present invention.
The rotor 50 according to the fourth embodiment includes a cylindrical rotor core 21, a rotating shaft 3, four magnet slots 22, four permanent magnets 23 embedded in these magnet slots 22, and a rotor core 21. , A plurality of bar slots 24 formed at equal intervals in the circumferential direction on the outer diameter side, a plurality of conductive permanent magnet bars 51, 52, 53, 54 disposed inside the plurality of bar slots 24; One end-side conductive end ring 27 and the other end-side conductive end ring 28 are connected to one end and the other end of the conductive permanent magnet bars 51, 52, 53, 54 and constitute the cage conductor 29.

A conductive permanent magnet bar 51 is buried in the bar slot 24 closest to the d-axis, a conductive permanent magnet bar 54 is buried in the bar slot 24 closest to the q-axis, and a bar slot 24 between the d-axis and the q-axis. The conductive permanent magnet bars 52 and 53 are embedded.
In FIG. 8, it is not shown that the conductive permanent magnet bars 51, 52, 53, and 54 are embedded in all the bar slots 24, but the conductive permanent magnets are provided in the bar slots 24 closest to the d-axis. The bar 51 is embedded, and the conductive permanent magnet bars 52, 53, 54 are embedded toward the bar slot 24 closest to the q axis.

The conductive permanent magnet bar 51 embedded in the bar slot 24 closest to the d-axis is a conductive permanent magnet having a large residual magnetic flux density B1.
The conductive permanent magnet bar 54 embedded in the bar slot 24 closest to the q-axis is a conductive permanent magnet having a small residual magnetic flux density B4.
Further, the residual magnetic flux densities B2 and B3 of the conductive permanent magnet bars 52 and 53 embedded between the conductive permanent magnet bar 51 and the conductive permanent magnet bar 54 and the residual magnetic flux of the conductive permanent magnet bars 51 and 54 are different. The relationship with the densities B1 and B4 is B1>B2>B3> B4.

As described above, in the fourth embodiment, the residual magnetic flux density of the conductive permanent magnet bar embedded in the plurality of bar slots 24 is changed from the conductive permanent magnet bar 51 closest to the d-axis to the conductive permanent magnet bar closest to the q-axis. It decreases monotonously in the order of the permanent magnet bar 54.
5 and FIG. 6, the conductive permanent magnet bars 51, 52, 53, and 54 embedded in the bar slot 24 on the upper right outer periphery have been described. However, the d-axis and q-axis bar slots other than the upper right outer periphery are described. The conductive permanent magnet bar embedded in 24 has the same configuration.

As described above, the residual magnetic flux density of the conductive permanent magnet bar is monotonously reduced from the conductive permanent magnet bar 51 closest to the d-axis to the conductive permanent magnet bar 54 closest to the q-axis. Thus, similarly to the third embodiment, it is possible to realize an increase in torque and a sufficient reduction in cogging torque and torque ripple.
That is, as shown in FIG. 7A, the magnetomotive force waveform when a plurality of conductive permanent magnet bars are not embedded in the circumferential direction on the outer diameter side of the rotor core 21 is embedded in the magnet slot 22. A magnetic flux is generated from the permanent magnet 23, and the waveform of the magnetomotive force generated by the magnetic flux has a rectangular wave shape indicated by the symbol A.

  On the other hand, the residual magnetic flux density of the conductive permanent magnet bar is monotonously decreased in the order from the conductive permanent magnet bar 51 closest to the d-axis to the conductive permanent magnet bar 54 closest to the q-axis. In this case, the magnetic flux is generated not only from the permanent magnet 23 but also from the conductive permanent magnet bars 51, 52, 53, 54, and the magnetic flux is generated from the permanent magnet 23 and the conductive permanent magnet bars 51, 52, 53, 54. As shown in FIG. 7B, the waveform of the magnetomotive force is on the upper side and both sides of the rectangular wave shape indicated by the reference symbol A generated by the magnetic flux of the permanent magnet 23, and the conductive permanent magnet bars 51, 52, 53, A shape is obtained by adding a gradually decreasing step-shaped waveform indicated by reference symbol B or a gradually increasing step-shaped waveform indicated by reference symbol C created by the magnetic flux 54.

That is, the waveform of the magnetomotive force generated by the magnetic flux from the permanent magnet 23 and the conductive permanent magnet bars 51, 52, 53, 54 approaches a sine wave shape.
As described above, when the waveform of the magnetomotive force generated by the magnetic fluxes from the permanent magnet 23 and the conductive permanent magnet bars 51, 52, 53, and 54 approaches a sine wave shape, the fundamental component of the magnetomotive force increases and the harmonics increase. The components decrease. An increase in the fundamental wave component increases the torque, and a decrease in the harmonic wave component reduces the cogging torque and the torque ripple.
Therefore, as in the fourth embodiment, the residual magnetic flux density of the conductive permanent magnet bar decreases monotonically from the conductive permanent magnet bar 51 closest to the d-axis to the conductive permanent magnet bar 54 closest to the q-axis. By doing so, it is possible to realize an increase in torque and a sufficient reduction in cogging torque and torque ripple.

Also, when the self-starting permanent magnet type electric motor of the fourth embodiment is operated at the synchronous speed, the self-starting type permanent magnet type motor is operated by the magnetic flux generated by the plurality of conductive permanent magnet bars 51, 52, 53, 54. Since the torque of the motor increases, when the same torque is required as in the case of the conventional self-starting permanent magnet motor, the size of the self-starting permanent magnet motor can be reduced and the current can be reduced. High efficiency can be achieved.
Furthermore, the torque of the self-starting permanent magnet motor is increased by the magnetic flux generated by the plurality of conductive permanent magnet bars 51, 52, 53, 54 without increasing the number of permanent magnets 23 embedded in the rotor core 21. Therefore, the number of parts and the manufacturing process can be reduced, and the manufacturing cost of the self-starting permanent magnet electric motor can be reduced.
The embodiments of the present invention have been described above, but the present invention is not limited thereto, and various changes and improvements can be made.

REFERENCE SIGNS LIST 1 self-starting permanent magnet motor 2 frame 3 rotating shaft 10 stator 20 rotor 11 stator core 12 slot 13 magnetic pole teeth 14 exciting coil 21 rotor core 22 magnet slot 23 permanent magnet 24 bar slot 25 conductive permanent magnet bar 26 magnetic pole 27 one end side conductive end ring 28 the other end side conductive end ring 29 cage conductor 30 rotor 40 rotors 41, 42, 43, 44 conductive permanent magnet bars 41a, 42a, 43a, 44a conductive permanent magnets Magnets 41b, 42b, 43b, 44b Conductive non-magnetic member 50 Rotors 51, 52, 53, 54 Conductive permanent magnet bar G Air gap

Claims (5)

A stator wound with an exciting coil;
Comprising a stator and a rotor rotatably arranged facing each other with a predetermined gap,
The rotor,
A cylindrical rotor core,
A plurality of bar slots provided on the outer diameter side of the rotor core at predetermined intervals in a circumferential direction and extending in a rotation axis direction;
A plurality of conductive permanent magnet bars comprising conductive permanent magnets embedded in these plurality of bar slots,
And a pair of end rings connected to both ends of the plurality of conductive permanent magnet bars. A plurality of magnet slots provided on the inner diameter side of the rotor core at predetermined intervals in a circumferential direction, and extending in the rotation axis direction;
The self-starting permanent magnet motor according to claim 1, further comprising: a plurality of permanent magnets embedded in the plurality of magnet slots. Assuming that the central axis of the permanent magnet for each magnetic pole formed by the plurality of permanent magnets is a d-axis, and an axis separated by an electrical angle of 90 ° from the d-axis is a q-axis,
The magnetic flux generated in the plurality of bar slots monotonously decreases in the order from the bar slot closest to the d-axis to the bar slot closest to the q-axis. Self-starting type permanent magnet motor. Assuming that the central axis of the permanent magnet for each magnetic pole formed by the plurality of permanent magnets is a d-axis, and an axis separated by an electrical angle of 90 ° from the d-axis is a q-axis,
The residual magnetic flux densities of the plurality of conductive permanent magnet bars are monotonously reduced in order from the conductive permanent magnet bar closest to the d-axis to the conductive permanent magnet bar closest to the q-axis. The self-starting permanent magnet electric motor according to claim 2, characterized in that:   The self-starting type permanent magnet electric motor according to any one of claims 1 to 4, wherein an alnico magnet is used as a material of the plurality of conductive permanent magnet bars.

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