JP5802487B2 - Permanent magnet rotating electric machine - Google Patents

Description

  Embodiments described herein relate generally to a permanent magnet type rotating electrical machine.

  Currently, a permanent magnet (hereinafter referred to as a variable magnetic magnet) in which the product of the coercive force and the magnetization direction thickness is small, and a permanent magnet (hereinafter referred to as a variable magnet magnetic force) in which the product of the coercive force and the magnetization direction thickness is greater than the variable magnet magnetic force There is a permanent magnet type rotating electric machine using a fixed magnetic force magnet). In such a permanent magnet type rotating electric machine, the flux linkage of the variable magnetic force magnet is irreversibly changed by the magnetic field generated by the magnetizing current. Therefore, the total flux linkage, which is the sum of the flux linkage of the variable magnetic magnet and the flux linkage of the fixed magnetic magnet, is variable by adjusting the amount and direction of the flux linkage of the variable magnet. . Magnetizing the variable magnetic magnet so as to generate an interlinkage magnetic flux in the same direction as the interlinkage magnetic flux of the fixed magnetic magnet is called magnetizing. On the contrary, demagnetization means that the variable magnetic magnet is magnetized so as to generate an interlinkage magnetic flux in a direction opposite to the interlinkage magnetic flux of the fixed magnetic magnet. Such a permanent magnet type rotating electric machine enables variable speed operation in a wide range from high speed to low speed to high speed.

JP 2006-280195 A JP 2008-48514 A JP 2010-124608 A

Design and control of embedded magnet synchronous motor, Yoji Takeda et al., Ohm

  In such a permanent magnet type rotating electrical machine, it is preferable that the waveform of the magnetic flux density distribution has a substantially sinusoidal shape when the gap magnetic flux density distribution between the rotor and the stator in one magnetic pole is viewed. The reason is that when the harmonic component of the magnetic flux density distribution increases, the iron loss of the rotor core and the stator core increases, and the output efficiency of the permanent magnet type rotating electrical machine decreases.

  However, when the variable magnetic force magnet is arranged in the center of the magnetic pole, the magnetic flux density in the vicinity of the magnetic pole center increases or decreases as the variable magnetic force magnet increases or decreases. When the magnetic flux density near the center of the magnetic pole decreases, the waveform of the magnetic flux density distribution changes from a substantially sine wave shape to a substantially rectangular wave shape. That is, the harmonic component of the magnetic flux density distribution increases. As a result, the iron loss generated in the stator core and the rotor core increases.

  An object of the present invention is to provide a permanent magnet type rotating electrical machine that can increase and decrease the gap magnetic flux density distribution between a rotor and a stator when a variable magnetic force magnet is increased or decreased.

  According to the embodiment, the permanent magnet type rotating electrical machine has a stator and a rotor. The stator has armature windings. The rotor has a rotor core, a first permanent magnet, and a second permanent magnet. The first permanent magnet is embedded in the rotor core. The second permanent magnet is disposed on both sides of the first permanent magnet, the amount of magnetic flux irreversibly changes due to a change in magnetization state due to a magnetic field formed by energizing the armature winding. Yes. The rotor core has a magnetic path in which the magnetic flux of the second permanent magnet is short-circuited, and an outer peripheral bridge having a width at which the magnetic flux density of the magnetic path is not saturated in the rotor core is located in the vicinity of the second permanent magnet. Have.

FIG. 3 is a developed cross-sectional view of one magnetic pole in the permanent magnet type rotating electrical machine according to the first embodiment. The figure which shows the flow of the magnetic flux at the time of magnetizing of the variable magnetic force magnet in the permanent magnet type rotary electric machine which concerns on 1st Embodiment. The figure which shows the flow of the magnetic flux at the time of demagnetization of the variable magnetic force magnet in the permanent-magnet-type rotary electric machine of 1st Embodiment. The expanded sectional view for 1 pole of the magnetic pole in the permanent magnet type rotary electric machine which concerns on 2nd Embodiment. The expanded sectional view for 1 pole of the magnetic pole in the permanent magnet type rotary electric machine which concerns on 3rd Embodiment.

Hereinafter, embodiments will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a developed cross-sectional view of one pole of a permanent magnet type rotating electrical machine 1 according to the first embodiment. The central axis direction of the magnetic pole 2 is the q axis, and the central axis direction between the magnetic poles is the d axis. The permanent magnet type rotating electrical machine 1 includes a stator 10 and a rotor 20. The stator 10 has a cylindrical shape and is arranged on the outer periphery of the rotor 20 through an air gap. The rotor 20 has a cylindrical shape and is arranged coaxially with the stator 10.

  The stator 10 has a stator core 101 and an armature winding 102. In the stator core 101, a plurality of armature windings 102 are embedded in the circumferential direction. When the three-phase alternating current is used, the armature winding 102 is wound in the order of U phase-V phase-W phase in the circumferential direction. The rotor 20 includes a rotor core 201, a fixed magnetic magnet 202, variable magnet magnetic forces 203 and 204, and short-circuit coils 205a and 205b. The rotor core 201 is configured by laminating silicon steel plates. The rotor core 201 has insertion holes 2011, 2012, and 2013 in the axial direction. The insertion hole 2011 is provided at the center of the magnetic pole 2. The insertion holes 2012 and 2013 are provided on both sides of the insertion hole 2011.

  The fixed magnetic magnet 202 is embedded in the insertion hole 2011 so that the magnetization direction is the q-axis direction. The variable magnetic force magnet 203 is embedded in the insertion hole 2012 so that the magnetization direction is the d-axis direction. The variable magnetic force magnet 204 is embedded in the insertion hole 2013 so that the magnetization direction is the d-axis direction. The variable magnetic magnets 203 and 204 are subjected to a magnetic field formed by a pulsed magnetizing current that is passed through the armature winding 102 for an extremely short time, and the magnetization direction changes irreversibly. The fixed magnetic magnet 202 and the variable magnetic magnets 203 and 204 embedded in the rotor core 201 as described above constitute a parallel circuit on the magnetic circuit and form the magnetic pole 2. Although FIG. 1 shows only the magnetic pole 2, the rotor core 201 has a plurality of magnetic poles formed in the circumferential direction. Since the other magnetic poles are formed in the same manner as the magnetic pole 2, the description thereof is omitted.

  Further, the rotor core 201 has outer bridges 2014 and 2015 between the insertion hole 2012 and the outer periphery of the rotor core 201 and between the insertion hole 2013 and the outer periphery of the rotor core 201, respectively. The outer peripheral bridge 2014 is a magnetic path that is provided in the vicinity of the end of the magnetic pole 2 (d-axis) and the magnetic fluxes of the fixed magnetic magnet 202 and the variable magnetic magnet 203 are short-circuited. Similarly, the outer peripheral bridge 2015 is provided in the vicinity of the end of the magnetic pole 2 and is a magnetic path in which the magnetic fluxes of the fixed magnetic magnet 202 and the variable magnetic magnet 204 are short-circuited. The operation of the outer peripheral bridges 2014 and 2015 will be described later.

  The short-circuit coils 205 a and 205 b are arranged in the axial direction of the rotor core 201 using the left and right gaps of the fixed magnetic magnet 202 in the insertion hole 2011. The short-circuit coils 205 a and 205 b are connected to each other and are wound around the rotor core 201 so as to surround the fixed magnetic magnet 202. The short-circuit coils 205a and 205b are conductive members. In place of the short-circuit coils 205a and 205b, a conductive plate through which eddy current flows may be used.

  The operation of the short-circuit coils 205a and 205b will be described. The short-circuiting coils 205a and 205b generate a short-circuit current due to a magnetic field generated by the magnetizing current that flows through the armature winding 102. The short-circuit coils 205a and 205b generate a magnetic field by a short-circuit current. In the fixed magnetic magnet 202, the direction of the magnetic flux generated in the short-circuit coils 205a and 205b is opposite to the direction of the magnetic flux generated in the armature winding 102. Therefore, in the fixed magnetic force magnet 202, the magnetic flux generated in the armature winding 102 is canceled by the magnetic flux generated in the short-circuit coils 205a and 205b. Therefore, the magnetic flux of the fixed magnetic magnet 202 hardly increases or decreases. In the variable magnetic magnets 203 and 204, the direction of the magnetic flux generated by the short-circuit coils 205 a and 205 b is the same as the direction of the magnetic flux generated by the armature winding 102. Therefore, in the variable magnetic force magnets 203 and 204, the magnetic flux generated in the armature winding 102 is strengthened by the magnetic flux generated in the short-circuit coils 205a and 205b. Therefore, the variable magnetic force magnets 203 and 204 are magnetized with a small magnetization current.

  That is, the short-circuit coils 205a and 205b act so as to concentrate the magnetic field generated in the armature winding 102 on the variable magnetic force magnets 203 and 204. In the first embodiment, an example in which the rotor 20 is provided with the short-circuit coils 205a and 205b will be described. However, the rotor 20 may not be provided with the short-circuit coils 205a and 205b. .

  According to the above configuration, the permanent magnet type rotating electrical machine 1 is magnetized by the magnetic field generated by the magnetizing current that is supplied to the armature winding 102 by the variable magnetic force magnets 203 and 204, so that the interlinkage magnetic flux amount of the fixed magnetic force magnet 202 is increased. The total amount of flux linkage that is the sum of the flux linkages of the variable magnetic magnets 203 and 204 can be adjusted over a wide range.

  In the low speed region, the variable magnetic magnets 203 and 204 are magnetized so that the interlinkage magnetic flux is in the same direction as the interlinkage magnetic flux of the fixed magnetic magnet 202. In particular, during the initial operation in the low speed region, the variable magnetic force magnets 203 and 204 are magnetized so that the linkage flux becomes the maximum amount, and thus the total linkage flux amount is maximized. Therefore, the torque and output of the permanent magnet type rotating electrical machine 1 are maximized.

  In the middle / high speed range, the variable magnetic magnets 203 and 204 are magnetized so that the flux linkage is smaller than that in the low speed zone, or the flux linkage is opposite to the flux linkage of the fixed magnetic magnet 202. Therefore, the total flux linkage is reduced more than the amount in the low speed region. Therefore, the rotation speed of the rotating electric machine of the permanent magnet type rotating electric machine 1 is increased.

  Next, the operation of the outer peripheral bridges 2014 and 2015 will be described. FIG. 2 is a cross-sectional view showing the flow of magnetic flux in the gap between the rotor 20 and the stator 10 when the variable magnetic force magnets 203 and 204 are magnetized. FIG. 3 is a cross-sectional view showing the flow of magnetic flux in the gap between the rotor 20 and the stator 10 when the variable magnetic force magnets 203 and 204 are demagnetized. The outer bridge 2014 has a width that does not saturate the magnetic flux density. The same applies to the outer bridge 2015. The magnetic flux of the fixed magnetic magnet 202 flows through the outer peripheral bridge 2014 and returns more easily to the fixed magnetic magnet 202 near the outer peripheral bridge 2014 than from the outer peripheral side of the rotor core 201 to the stator core 101. The magnetic flux of the variable magnetic force magnet 203 also flows through the outer peripheral bridge 2015 and returns to the variable magnetic force magnet 203 near the outer peripheral bridge 2014 rather than flowing from the outer peripheral side of the rotor core 201 to the stator core 101. Similarly, the magnetic flux of the fixed magnetic force magnet 202 flows through the outer peripheral bridge 2015 and returns to the fixed magnetic force magnet 202 in the vicinity of the outer peripheral bridge 2015 rather than flowing from the outer peripheral side of the rotor core 201 to the stator core 101. The magnetic flux of the variable magnetic force magnet 204 also flows through the outer peripheral bridge 2015 and returns to the variable magnetic force magnet 204 near the outer peripheral bridge 2015 rather than flowing from the outer peripheral side of the rotor core 201 to the stator core 101. That is, since the magnetic fluxes of the fixed magnetic magnet 202 and the variable magnetic magnets 203 and 204 are confined in the rotor core 201, the interlinkage magnetic flux at both ends of the magnetic pole 2 is reduced. Therefore, when looking at the gap magnetic flux density distribution between the rotor 20 and the stator 10 for one magnetic pole, the waveform of the gap magnetic flux density distribution at the time of magnetizing and demagnetizing the variable magnetic force magnets 203 and 204 is Also approaches a substantially sinusoidal shape with the peak at the center of the magnetic pole. If a gap magnetic flux density distribution harmonic component is included, the iron loss increases due to the harmonic component. Therefore, bringing the gap magnetic flux density distribution waveform closer to a substantially sinusoidal shape is more effective at the time of increasing the magnetic flux than at the time of demagnetizing.

  According to the first embodiment, since the gap magnetic flux density distribution at the time of magnetizing and demagnetizing the variable magnetic force magnets 203 and 204 can be increased or decreased in a substantially sinusoidal shape, it is generated inside the permanent magnet type rotating electrical machine 1 by the magnetic flux density harmonics. Therefore, it is possible to provide the permanent magnet type rotating electrical machine 1 that can reduce the iron loss and that is highly reliable and highly efficient.

(Second Embodiment)
FIG. 4 is a developed cross-sectional view of one magnetic pole of the permanent magnet type rotating electrical machine 1 according to the second embodiment. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In the insertion hole 2012, a variable magnetic magnet 206 and a fixed magnetic magnet 207 are stacked (in series) so as to have the same magnetization direction. In the insertion hole 2013, a variable magnetic magnet 208 and a fixed magnetic magnet 209 are laminated (in series) so that the magnetization directions are the same. The variable magnetic force magnet 206 is disposed on the outer peripheral side of the rotor core 201 in the magnetization direction with respect to the fixed magnetic force magnet 207, but may be disposed opposite to the fixed magnetic force magnet 207. The variable magnetic magnet 206 and the fixed magnetic magnet 207 may be arranged side by side in the direction perpendicular to the magnetization. The same applies to the arrangement of the variable magnetic magnet 208 and the fixed magnetic magnet 209. FIG. 4 shows only the magnetic pole 2, but the rotor core 201 has a plurality of magnetic poles formed in the circumferential direction. Since the other magnetic poles are formed in the same manner as the magnetic pole 2, the description thereof is omitted. The permanent magnet type rotating electrical machine 1 according to the second embodiment has the same effects as those of the first embodiment.

(Third embodiment)
FIG. 5 is a developed cross-sectional view of one pole of the magnetic pole of the permanent magnet type rotating electrical machine 1 in the third embodiment. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. The rotor core 201 has insertion holes 2016 and 2017 in the axial direction. The insertion holes 2016 and 2017 are provided in the rotor core 201 in a V shape from the center of the magnetic pole 2 of the rotor core 201 toward the outer peripheral side on both sides centered on the magnetic pole 2.

  In the insertion hole 2016, the fixed magnetic magnet 210 is disposed on the center side of the magnetic pole 2. Furthermore, in the insertion hole 2016, the variable magnetic magnet 211 and the fixed magnetic magnet 212 are laminated on the outer peripheral side of the stator core 201 so that the magnetization directions are the same. The variable magnetic magnet 211 is arranged on the outer peripheral side of the rotor core 201 in the magnetization direction with respect to the fixed magnetic magnet 212, but may be arranged opposite to the stator magnetic magnet 212. The variable magnetic magnet 211 and the fixed magnetic magnet 212 may be arranged side by side in the direction perpendicular to the magnetization. Further, a variable magnetic force magnet may be disposed instead of the fixed magnetic force magnet 212.

  Similarly, in the insertion hole 2017, the fixed magnetic force magnet 213 is disposed on the center side of the magnetic pole 2. In the insertion hole 2017, the variable magnetic magnet 214 and the fixed magnetic magnet 215 are laminated on the outer peripheral side of the stator core 201 so that the magnetization directions are the same.

  The variable magnetic force magnet 214 is disposed on the outer peripheral side of the rotor core 201 in the magnetization direction with respect to the fixed magnetic force magnet 215, but may be disposed opposite to the stator magnetic force magnet 215. The variable magnetic magnet 214 and the fixed magnetic magnet 215 may be arranged side by side in the direction perpendicular to the magnetization. In addition, a variable magnetic force magnet may be arranged instead of the fixed magnetic force magnet 214.

  In the insertion hole 2016, the short-circuit coil 216 a is disposed between the fixed magnetic magnet 210 and the variable magnetic magnet 211 and in the axial direction of the rotor core 201. In the insertion hole 2017, the short-circuit coil 216 b is disposed between the fixed magnetic magnet 213 and the variable magnetic magnet 214 and in the axial direction of the rotor core 201. The short-circuit coil 216a and the short-circuit coil 216b are connected to each other. The short-circuit coils 216a and 216b operate in the same manner as the short-circuit coils 205a and 205b, and thus the description thereof is omitted.

  Although FIG. 5 shows only the magnetic pole 2, the rotor core 201 has a plurality of magnetic poles formed in the circumferential direction. Since the other magnetic poles are formed in the same manner as the magnetic pole 2, the description thereof is omitted. The permanent magnet type rotating electrical machine 1 according to the third embodiment has the same effects as those of the first embodiment.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Permanent magnet type rotary electric machine, 2 ... Magnetic pole, 10 ... Stator, 20 ... Rotor, 101 ... Stator iron core, 102 ... Armature winding, 201 ... Rotor iron core, 202 ... Fixed magnetic magnet, 203 ... Variable Magnetic magnet 204, Variable magnetic magnet 205a Short circuit coil 205b Short coil 206 Variable magnetic magnet 207 Fixed magnetic magnet 208 Variable magnetic magnet 209 Fixed magnetic magnet 210 Fixed magnetic magnet 211 ... variable magnetic magnet, 212 ... fixed magnetic magnet, 213 ... fixed magnetic magnet, 214 ... variable magnetic magnet, 215 ... fixed magnetic magnet, 216a ... short circuit coil, 216b ... short circuit coil, 2011 ... insertion hole, 2012 ... insertion hole, 2013 ... insertion hole, 2014 ... outer periphery bridge, 2015 ... outer periphery bridge, 2016 ... insertion hole, 2017 ... insertion hole.

Claims (4)

A stator having armature windings;
The amount of magnetic flux changes irreversibly by changing the magnetization state by a magnetic field formed by energizing the rotor core, the first permanent magnet embedded in the rotor core, and the armature winding, the permanent magnet rotating electrical machine to have a rotor and a second permanent magnet disposed on opposite sides of said first permanent magnet,
The rotor core has a magnetic flux of the second permanent magnets has a magnetic path short-circuiting through the outer peripheral bridge width outer peripheral bridge the second of the magnetic flux density of the magnetic path is not saturated in the rotor core possess near permanent magnet, close the magnetic flux density distribution in the gap of the said rotor and the stator by changing the magnetization state of the second permanent magnet in a substantially sinusoidal magnetic flux amount of the second permanent magnet Even if irreversibly changes, the amplitude of the magnetic flux density distribution is increased or decreased while maintaining a substantially sinusoidal shape ,
Permanent magnet type rotating electric machine.   The permanent magnet rotating electrical machine according to claim 1, wherein the first permanent magnet has a product of a coercive force and a magnetization direction thickness larger than that of the second permanent magnet.   The permanent magnet type rotating electrical machine according to claim 2, wherein the first permanent magnet is disposed in the vicinity of the center of the magnetic pole.   The rotor is disposed in the vicinity of the second permanent magnet, and is opposite to a magnetic field formed by energizing the armature winding by a current generated by a magnetic field formed by energizing the armature winding. The permanent magnet type rotating electrical machine according to claim 3, further comprising a conductive member that generates a magnetic field in a direction.

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