TWI454020B - Permanent magnet synchronous motor - Google Patents

Description

Permanent magnet synchronous motor

The present invention relates to a permanent magnet type synchronous motor that suppresses torque ripple.

In the permanent magnet type synchronous motor in which a set of windings are collectively applied to each of the teeth, when the number of poles and the number of slots are appropriately selected, the cogging torque at the time of non-energization can be largely given. reduce. However, in this case, the torque ripple at the time of energization becomes a problem.

Such torque chopping is caused by distortion of the induced voltage. Therefore, in order to reduce the induced voltage harmonics, the magnet shape and the like are studied, and a design in which the gap magnetic flux density distribution is closer to a sinusoidal waveform is performed. Further, a technique of dividing a magnet and changing the magnetic flux density of the magnet to make the gap magnetic flux density close to a sinusoidal wave has been proposed (for example, see Patent Document 1).

(previous technical literature) (Patent Literature)

Patent Document 1: Japanese Patent Laid-Open Publication No. 2008-067561

However, there are problems in the prior art as described below.

In a motor with a smaller diameter, the diameter of the rotor also becomes smaller. Therefore, it is difficult to attach a segment magnet (single magnet). In the case of magnets, radial anisotropy is used. The case of a ring-shaped magnet or a highly anisotropic ring magnet. Here, since the extremely anisotropic ring magnet is relatively expensive compared to the radial anisotropic ring magnet, a radial anisotropic ring magnet or a segment magnet is often used in a motor having a small diameter.

When the segment magnet is attached, its shape is studied, whereby the gap magnetic flux density can be made close to a sine wave. In addition, when a highly anisotropic ring magnet is used, the gap magnetic flux density distribution is distributed in a sinusoidal shape because of a special orientation.

However, when a radial anisotropic ring magnet is used, in general, the gap magnetic flux density is a trapezoidal shape. Therefore, the distortion of the induced voltage becomes larger than that of the segment magnet or the extremely anisotropic ring magnet, and the torque ripple thereof also becomes large.

On the other hand, in the permanent magnet type synchronous motor, when the rotor magnet (rotator) is rotated by external driving when the winding is not energized, torque ripple generated between the stator core and the rotor occurs. Ingredients (cogging torque).

In general, the cogging torque is due to the mechanical rotation of the rotor, resulting in the number of slots of the stator and the number of pulsations of the least common multiple of the number of poles of the permanent magnet, and the magnitude of the cogging torque is inversely proportional to The number of pulsations. Therefore, in order to reduce the cogging torque of the motor, a combination is selected in which the number of slots of the stator and the minimum common multiple of the number of magnetic poles of the permanent magnet are increased.

In the motor of the combination of the larger and the smaller common multiple, there is a motor driven by a so-called three-phase power source having Z (Z series natural number) stators formed in an annular shape and having windings (coils) applied thereto, and With 2P pole (P A permanent magnet of a natural number, and the value of Z/(3 (phase) × 2P) becomes a motor of 2/5 or 2/7.

In the motor where the value of Z/(3 (phase) × 2P) is 2/5 or 2/7, theoretically, when the fundamental wave is set to once, the winding coefficient of the fifth and seventh harmonics is very Small 0.067. Therefore, when the fundamental wave frequency is set to 1f of the electrical angle, the 6f component of the torque ripple (torque chopping) at the time of energization hardly occurs. On the other hand, the 11th and 13th winding coefficients of the harmonics are higher at 0.933. Therefore, a 12f component of torque ripple (torque chopping) at the time of energization is generated.

The present invention has been made in order to solve the above problems, and an object of the invention is to provide a permanent magnet type synchronous motor in which a 12f component of a torque chopping can be depressed when a radial anisotropic ring magnet is used in a motor having a small diameter.

The permanent magnet type synchronous motor of the present invention has Z (Z series natural number) stators, is formed in a ring shape and is provided with windings; and 2P magnetic poles (P system natural number) permanent magnets, and Z/(3( The value of the phase × 2 P) is 2/5 or 2/7. In the permanent magnet synchronous motor, a radial anisotropic ring magnet is used as the permanent magnet, and there is no slot opening between the adjacent stator front end portions. When the front end width of the flange portion constituting the distal end portion of the stator is h and the root width is tw, the radial anisotropic annular magnet is in the relationship between the flat region of the magnetization waveform and the transition region: When the shape of the stator satisfies the condition of tw/h=1, the transition region is set and magnetized so that the ratio of the flat region of the single magnetic pole becomes 55% to 80%; the shape of the stator satisfies 1<tw/h<3. Flat condition with a single magnetic pole The migration region is set and magnetized in such a manner that the ratio of the domains becomes 55% to 90%; and when the shape of the stator satisfies the condition of 3 ≦tw/h, the ratio of the flat region of the single magnetic pole becomes 55% to 95%. The way to set up the migration area and make it magnetized.

Further, the permanent magnet type synchronous motor of the present invention has Z (Z series natural number) stators, is formed in a ring shape and is provided with windings, and 2P poles (P system natural number) permanent magnets, and Z/( The value of 3 (phase) × 2P) is 2/5 or 2/7. In the permanent magnet synchronous motor, a radial anisotropic ring magnet is used as a permanent magnet, and a groove is formed between the adjacent stator front end portions. In the opening portion, when the width of the front end of the flange portion constituting the distal end portion of the stator is h, the width of the root portion is tw, and the width of the groove opening portion is bg, the radial anisotropic ring magnet is magnetized. In the relationship between the flat region and the transition region: (1) When the relationship between the width bg of the groove opening portion and the width h of the tip end portion of the flange portion satisfies h/bg=1, the shape of the stator satisfies tw/h=1. In the case of the condition, the transition region is set and magnetized so that the ratio of the flat region of the single magnetic pole becomes 55% to 95%; when the shape of the stator satisfies the condition of 1<tw/h<3, the flat region of the single magnetic pole The ratio becomes 55% to 95% in a way to set the migration area and make it magnetized; and the shape of the stator satisfies 3≦tw/ In the case of h, the transition region is provided and magnetized so that the ratio of the flat region of the single magnetic pole is 55% to 80%; and (2) the relationship between the width bg of the groove opening portion and the width h of the tip end portion of the flange portion When 1<h/bg<3 is satisfied, when the shape of the stator satisfies the condition of tw/h=1, the transition region is set and magnetized so that the ratio of the flat region of the single magnetic pole becomes 55% to 80%; Stator shape When the condition of 1<tw/h<3 is satisfied, the transition region is set and magnetized so that the ratio of the flat region of the single magnetic pole becomes 55% to 95%; and when the shape of the stator satisfies the condition of 3 ≦tw/h The migration region is provided and magnetized so that the ratio of the flat region of the single magnetic pole becomes 55% to 95%; (3) the relationship between the width bg of the groove opening portion and the width h of the front end of the flange portion satisfies 3≦h /bg, when the shape of the stator satisfies the condition of tw/h=1, the transition region is set and magnetized so that the ratio of the flat region of the single magnetic pole becomes 55% to 90%; the shape of the stator satisfies 1< In the condition of tw/h<3, the migration region is set and magnetized so that the ratio of the flat region of the single magnetic pole becomes 55% to 95%; and when the shape of the stator satisfies the condition of 3 ≦tw/h, the single The migration region is set and magnetized in such a manner that the ratio of the flat regions of the magnetic poles is 55% to 95%.

According to the permanent magnet type synchronous motor of the present invention, in the relationship between the flat region of the magnetization waveform of the radial anisotropy ring magnet and the transition region, the ratio of the flat region is designed to a suitable value by the corresponding tooth shape to reduce the gap magnetic flux density. By distributing the harmonic components, it is possible to obtain a permanent magnet type synchronous motor capable of lowering the 12f component of the torque chopping when a radial anisotropic ring magnet is used for a motor having a small diameter.

Hereinafter, a preferred embodiment of the permanent magnet type synchronous motor according to the present invention will be described using a schematic diagram.

The present invention is a three-phase power-driven motor having: Z (Z-system natural number) stators formed in a circular shape and having windings (coils); And has a permanent magnet of 2P pole (P system natural number), and Z/(3 (phase) × 2P) has a value of 2/5 or 2/7, in which the magnetic susceptibility of the ring magnet is generated. The change, and the migration area is characterized as being able to suppress the 12f component of the torque chopping. Further, in the following embodiments, the case where the value of Z/(3 (phase) × 2P) is 2/5 is taken as an example, but it is verified that the same result can be obtained when the value is 2/7. And the same effect.

(First embodiment)

Fig. 1 is a cross-sectional view showing a cross section perpendicular to the axial direction of the permanent magnet type synchronous motor according to the first embodiment of the present invention, and shows a 10-pole 12-slot motor when Z = 12 and 2P = 10. Therefore, the value of Z/(3 (phase) × 2P) corresponds to 12/(3 × 10) = 2/5. The permanent magnet synchronous motor of the first embodiment includes a stator core 10, a rotor core 20, and a radial anisotropic ring magnet 30, and the stator core 10 has a plurality of teeth portions 11.

Fig. 2 is an enlarged view of the stator core 10 of the permanent magnet synchronous motor according to the first embodiment of the present invention, and corresponds to an enlarged view of the tooth portion 11 of Fig. 1 . In the 10 pole 12-slot motor shown in Fig. 1, as shown in Fig. 2, a shape having no void portion (so-called groove opening portion) is formed between adjacent tooth portions 11. Further, each of the tooth portions 11 has a flange portion 12 along the circumferential direction of the rotor core 20. The symbol "h" in the second figure shows the width of the front end of the flange portion 12, and the symbol "tw" indicates the convex portion. The width of the root portion of the rim portion 12.

In such a tooth shape, since there is no groove opening portion, the change in the permeance of the magnet is small. Therefore, the cogging effect caused by the pulsation amount of the least common multiple of the number of slots and the number of magnetic poles of the permanent magnet can be changed. The moment is depressed. However, on the other hand, the linearity of the torque is deteriorated when the magnetic flux is leaked between the grooves at the time of overload.

Fig. 3 is an enlarged view of the rotor core 20 of the permanent magnet type synchronous motor according to the first embodiment of the present invention, and shows the magnet orientation of the rotor. In addition, the radial anisotropy is annular, and the magnet 30 is a magnet having a plurality of pole numbers in one magnet. For the sake of convenience, the boundary between the pole and the pole is illustrated in FIG. 3, but in an actual object, The boundary between the pole and the pole as shown in Fig. 3 cannot be visually observed.

Fig. 4 is a view showing a magnetic flux density waveform when a radial anisotropic ring magnet 30 is used in the permanent magnet type synchronous motor according to the first embodiment of the present invention. Further, Fig. 5 is a view showing the relationship between the ratio of the flat area of the single magnetic pole of the first embodiment of the present invention to the ratio of the no-load induced voltage. Here, the "ratio of the flat region" on the horizontal axis corresponds to the ratio of the flat region A1 to the region A3 of the single magnetic pole.

In addition, the "ratio of the no-load induced voltage" of the vertical axis appears as a ratio when the maximum value of each of the no-load induced voltages when the ratio of the flat regions is changed to 100%. When the ratio of the flat region is set to the maximum, the ratio of the flat region on the horizontal axis is about 97%, and the horizontal axis is 97%, and the no-load induced voltage on the vertical axis shows 100% of the maximum value. .

The larger the ratio of the flat region A1 of the magnetic flux density waveform shown in the previous FIG. 4 (that is, the smaller the ratio of the migration region A2), the larger the load-free induced voltage becomes as shown in FIG. In motors of the same size, the higher the no-load induced voltage, the larger the output. Therefore, the migration area A2 The increase will cause the output of the motor to drop.

When the drop of the no-load induced voltage is suppressed to 10% or less (that is, the ratio of the no-load induced voltage is set to 90% or more in FIG. 5), the ratio of the flat region A1 must be 55% or more. Further, the relationship between the ratio of the no-load induced voltage with respect to the ratio of the flat region A1 shown in FIG. 5 does not depend on the shape of the flange portion 12 of the tooth portion 11, regardless of the width tw of the root portion relative to the previous display. The ratio of the width h of the tip end of the flange portion 12 of the tooth portion 11 in Fig. 2 is the same value.

Therefore, when the ratio of the width tw of the root portion to the width h of the tip end portion of the flange portion 12 of the tooth portion 11 is changed, the value of the component of the torque chopping 12f can be reduced. Fig. 6 is a graph showing the relationship between the ratio of the flat region of the magnetic flux density waveform of the single magnetic pole of the first embodiment of the present invention and the magnitude of the component of the torque chopping 12f.

This sixth figure shows three patterns which are changed with respect to the ratio of the width tw of the root portion to the width h of the front end of the flange portion 12 of the tooth portion 11 shown in the previous FIG. 2, the ratio of the flat region Relationship with the size of the 12f component of the torque chopping. Further, the three modes in which the ratio of the width tw of the root portion to the width h of the tip end of the flange portion 12 is changed are the following equations (1) to (3).

[Mode 1] tw/h=1(1)

[Mode 2] 1<tw/h<3(2)

[Mode 3] 3≦tw/h(3)

With respect to all of the modes 1 to 3, as shown in the previous fifth figure, when the "flat area ratio" of the horizontal axis is about 97%, the no-load induced voltage is maximum. Therefore, in the waveforms of the respective modes 1 to 3 of Fig. 6, the size is smaller when the ratio of the "torque chopping 12f component" to the "flat region" is about 97%. The range of the "ratio of the flat area" is as follows.

Range of "flat area ratio" in [Mode 1] = 55% to 80% (4)

Range of "flat area ratio" in [Mode 2] = 55% to 90% (5)

Range of "flat area ratio" in [Mode 3] = 55% to 95% (6)

In the mode 1, when the ratio of the "flat area ratio" is 85% to 95%, the "torque chopping 12f component" is about 97% of the "flat area ratio". The magnitude of the torque chopping 12f component is larger. Therefore, the effect of reducing the value of the component of the torque chopping 12f cannot be obtained, and the range of the "ratio of the flat region" for reducing the value of the component of the torque chopping 12f is as shown in the above formula (4). , from 55% to 80%.

On the other hand, in the mode 2, when the "ratio of the flat region" is 95%, the "torque chopping 12f component" is about 97% when the "ratio of the flat region" is about 97%. The size of 12f ingredients is roughly equal. Therefore, the effect of reducing the value of the component of the torque chopping 12f is small, and the range of the "ratio of the flat region" for reducing the value of the component of the torque chopping 12f is as described in the above formula (5). Shown, 55% to 90%.

In the mode 3, the "torque chopping 12f component size" in the range of the "flat region ratio" is 95% or less, and the "torque region ratio" is about 97%. The size of the chopping 12f component is smaller. Therefore, the range of the "ratio of the flat region" in order to reduce the value of the component of the torque chopping 12f is 55% to 95% as shown in the above formula (6).

Therefore, the shape of the flange portion 12 of the tooth portion 11 corresponds to the patterns 1 to 3 of the above-described respective formulas (1) to (3), in the range of the above respective formulas (4) to (6). By setting the "ratio of the flat area", it is possible to suppress the drop of the no-load induced voltage to 10% or less, and to reduce the 12f component of the torque chopping.

As described above, according to the first embodiment, the "ratio of the flat area" is set within an appropriate range in accordance with the shape of the flange portion of the tooth portion, whereby the radial difference is used even in a motor having a small diameter. In the case of a square ring magnet, the drop in the no-load induced voltage can be suppressed to 10% or less, and the 12f component of the torque chopping can be reduced.

(Second embodiment)

In the first embodiment, a case has been described in which a radial anisotropic ring magnet is used for a motor having a small diameter without a gap portion (so-called groove opening portion) between adjacent tooth portions 11. In contrast, in In the second embodiment, a case where a radial anisotropic ring magnet is used for a motor having a small diameter in a shape in which a gap portion (so-called groove opening portion 13) is provided between adjacent tooth portions 11 is described.

Fig. 7 is a cross-sectional view showing a cross section in the axial direction of the permanent magnet type synchronous motor according to the second embodiment of the present invention, and shows a 10-pole 12-slot motor when Z = 12 and 2P = 10. Therefore, the value of Z/(3 (phase) × 2P) corresponds to 12/(3 × 10) = 2/5. The permanent magnet synchronous motor of FIG. 7 includes a stator core 10, a rotor core 20, and a radial anisotropic ring magnet 30, and the stator core 10 has a plurality of teeth portions 11.

Fig. 8 is an enlarged view of the stator core 20 of the permanent magnet type synchronous motor according to the second embodiment of the present invention, and corresponds to an enlarged view of the tooth portion of Fig. 7. In the 10 pole 12-slot motor shown in Fig. 7, as shown in Fig. 8, a shape having a void portion (so-called groove opening portion 13) is formed between adjacent tooth portions 11. Further, each of the tooth portions 11 has a flange portion 12 along the circumferential direction of the rotor core 20. The symbol "h" in Fig. 8 indicates the width of the front end of the flange portion 12, and the symbol "tw" indicates the convex portion. The width of the root portion of the rim portion 12. In addition, the symbol "bg" in Fig. 8 shows the width of the opening portion 13.

In such a tooth shape, since the groove opening portion 13 is present, the change in the magnetic permeability of the magnet is larger than that in the second drawing of the first embodiment. Therefore, the cogging torque generated by the pulsation amount of the least common multiple of the number of slots and the number of magnetic poles of the permanent magnet is larger than that in the case of the tooth shape of the second embodiment of the first embodiment. However, on the other hand, the leakage magnetic flux between the slots drops during overload, and the previous first embodiment In the case of the tooth shape of the second figure of the state, the linearity of the torque is improved.

Fig. 9 is a view showing the relationship of the ratio of the no-load induced voltage to the ratio of the flat region of the single magnetic pole of the second embodiment of the present invention. Here, the "ratio of the flat region" on the horizontal axis corresponds to the ratio of the flat region A1 to the region A3 of the single magnetic pole. In the second embodiment, as in the first embodiment, the ratio of the flat region A1 of the magnetic flux density waveform is larger (that is, the ratio of the transition region A2 is smaller), as shown in Fig. 9, no load The induced voltage becomes larger.

Therefore, when the drop of the no-load induced voltage is suppressed to 10% or less (that is, the ratio of the no-load induced voltage is set to 90% or more in FIG. 9), the ratio of the flat region A1 must be 55% or more. Further, the relationship between the ratio of the no-load induced voltage with respect to the ratio of the flat region shown in the ninth graph does not depend on the shape of the flange portion 12 of the tooth portion 11, regardless of the width tw of the root portion relative to the previous display. In the figure 8, the ratio of the width h of the tip end of the flange portion 12 of the tooth portion 11 and the width bg of the groove opening portion have the same relationship.

Therefore, when the ratio of the width tw of the root portion to the width h of the front end of the flange portion 12 of the tooth portion 11 is described, the value of the component of the torque ripple 12f can be reduced. Further, in the second embodiment, the width bg of the groove opening portion 13 is included as a parameter in addition to the ratio of the width tw of the root portion of the tooth portion 11 to the width h of the tip end portion of the flange portion 12. Therefore, the value of h/bg is divided into the following three conditions, and the condition that the value of the torque chopping 12f component can be reduced is reviewed.

[Condition 1] h/bg=1(7)

[Condition 2] 1<h/bg<3(8)

[Condition 3] 3≦h/bg(9)

First, the case where h/bg=1 is set as shown in the above formula (7) is reviewed. Fig. 10 is a graph showing the ratio and torque of a flat region of a magnetic flux density waveform of a single magnetic pole when the tip end shape of the permanent magnet synchronous motor according to the second embodiment of the present invention is the condition 1 (h/bg = 1). A diagram of the size of the wave 12f component. In the tenth graph, the ratio of the flat regions of the respective modes of the mathematical expressions (1) to (3) is displayed in the same manner as in the sixth embodiment of the first embodiment, under the condition of h/bg=1. It is related to the magnitude of the component of the torque chopping 12f.

With respect to all of the modes 1 to 3, when the "flat area ratio" on the horizontal axis is about 97%, as shown in the previous FIG. 9, the no-load induced voltage is maximum. Therefore, in the waveforms of the mode 1 to the mode 3 in Fig. 10, the size is smaller when the ratio of the "torque chopping 12f component" to the "flat region" is about 97%. The range of the "ratio of the flat area" is as follows.

Range of "flat area ratio" in [Mode 1] = 55% to 95% (10)

Range of "flat area ratio" in [Mode 2] = 55% to 95% (11)

Range of "flat area ratio" in [Mode 3] = 55% to 80% (12)

In the modes 1 and 2, when the ratio of the "flat area" is 95% or less, the "torque chopping 12f component" is a torque of about 97% when the ratio of the flat region is about 97%. The size of the chopping 12f component is smaller. Therefore, the range of the "ratio of the flat region" in order to reduce the value of the component of the torque chopping 12f is 55% to 95% as shown in the above formulas (10) and (11).

On the other hand, in the mode 3, when the range of the "flat area ratio" is 85% to 95%, the "the magnitude of the torque chopping 12f component" is about 97% when the ratio of the "flat area" is about 97%. The magnitude of the component of the torque chopping 12f is large. Therefore, the effect of reducing the value of the component of the torque chopping 12f cannot be obtained, and the range of the "ratio of the flat region" for reducing the value of the component of the torque chopping 12f is as shown in the above formula (12). It is 55% to 80%.

Therefore, when h/bg=1, the shape of the flange portion 12 of the tooth portion 11 corresponds to the patterns 1 to 3 of the above-described different formulas (1) to (3), in each of the above (10th) In the range of the formula (12), the "ratio of the flat region" is set so that the drop of the no-load induced voltage can be suppressed to 10% or less, and the 12f component of the torque chopping can be reduced.

Next, the case where 1<h/bg<3 is set as shown in the above formula (8) is reviewed. 11 is a ratio of a flat region of a magnetic flux density waveform of a single magnetic pole when the tip end shape of the permanent magnet synchronous motor according to the second embodiment of the present invention is the condition 2 (1<h/bg<3), and turn The relationship between the size of the matrix 12f component. In the eleventh diagram, the flat regions of the respective modes of the mathematical expressions (1) to (3) are displayed under the condition of 1 < h/bg < 3 as in the sixth drawing of the first embodiment. The ratio is related to the magnitude of the component of the torque chopping 12f.

With respect to all of the modes 1 to 3, when the "flat area ratio" on the horizontal axis is about 97%, as shown in the previous FIG. 9, the no-load induced voltage is maximum. Therefore, in the waveforms of the mode 1 to the mode 3 in Fig. 11, the size is smaller when the ratio of the "torque chopping 12f component" to the "flat region" is about 97%. The range of the "ratio of the flat area" is as follows.

Range of "flat area ratio" in [Mode 1] = 55% to 80% (13)

Range of "flat area ratio" in [Mode 2] = 55% to 95% (14)

Range of "flat area ratio" in [Mode 3] = 55% to 95% (15)

In other words, in the mode 1, when the range of the "flat area ratio" is 85% to 95%, the "torque chopping 12f component size" is about 97% when the "flat area ratio" is about 97%. The size of the matrix wave 12f component is larger. Therefore, the effect of reducing the value of the component of the torque chopping 12f cannot be obtained, and the range of the "ratio of the flat region" for reducing the value of the component of the torque chopping 12f is as shown in the above formula (13). , from 55% to 80%.

On the other hand, in modes 2 and 3, the "ratio of the flat area" The "torque chopping 12f component size" in the range of 95% or less is smaller than the "torque chopping 12f component" when the ratio of the "flat region" is about 97%. Therefore, the range of the "ratio of the flat region" in order to reduce the value of the component of the torque chopping 12f is 55% to 95% as shown in the above formulas (14) and (15).

Therefore, when 1<h/bg<3, the shape of the flange portion 12 of the tooth portion 11 corresponds to the patterns 1 to 3 of the above-described different formulas (1) to (3), in each of the above-mentioned In the range of (13) to (15), the "ratio of the flat region" is set, whereby the drop in the no-load induced voltage can be suppressed to 10% or less, and the 12f component of the torque chopping can be reduced.

Next, the case where 3 ≦h/bg is set as shown in the above formula (9) is reviewed. Fig. 12 is a graph showing the ratio of the flat region of the magnetic flux density waveform of the single magnetic pole when the tip end shape of the permanent magnet synchronous motor according to the second embodiment of the present invention is the condition 3 (3 ≦ h/bg), and the torque. A diagram showing the size of the chopping 12f component. This Fig. 12 shows the ratio of the flat regions of the respective modes of the mathematical expressions (1) to (3) in the same manner as in the sixth drawing of the first embodiment, under the condition of 3 ≦h/bg. It is related to the magnitude of the component of the torque chopping 12f.

With respect to all of the modes 1 to 3, when the "flat area ratio" on the horizontal axis is about 97%, as shown in the previous FIG. 9, the no-load induced voltage is maximum. Therefore, in the waveforms of the mode 1 to the mode 3 in Fig. 12, when the "the ratio of the component of the torque chopping 12f" to the "flat region" is about 97%, the size is smaller. The range of the ratio of the flat area is as follows.

Range of "flat area ratio" in [Mode 1] = 55% to 90% (16)

Range of "flat area ratio" in [Mode 2] = 55% to 95% (17)

Range of "flat area ratio" in [Mode 3] = 55% to 95% (18)

In the mode 1, the "torque chopping 12f component" when the "flat area ratio" is 95% is "torque chopping 12f component" when the "ratio of the flat region" is about 97%. The size is larger. Therefore, the effect of reducing the value of the component of the torque chopping 12f cannot be obtained, and the range of the "ratio of the flat region" for reducing the value of the component of the torque chopping 12f is as shown in the above formula (16). , from 55% to 90%.

On the other hand, in the mode 3, when the "ratio of the flat region" is 95% or less, the "torque chopping 12f component" is a torque of about 97% when the ratio of the flat region is about 97%. The size of the chopping 12f component is smaller. Therefore, the range of the "ratio of the flat region" in order to reduce the value of the component of the torque chopping 12f is 55% to 95% as shown in the above equations (17) and (18).

Therefore, when 3 ≦h/bg is set, the shape of the flange portion 12 of the tooth portion 11 corresponds to the patterns 1 to 3 of the above-described different formulas (1) to (3), in each of the above (16th) In the range of the formula (18), the "ratio of the flat region" is set, whereby the drop in the no-load induced voltage can be suppressed to 10% or less, and the 12f component of the torque chopping can be reduced.

As described above, according to the second embodiment, even if there is a groove opening portion In this case, the "ratio of the flat area" is set within an appropriate range in accordance with the shape of the flange portion of the tooth portion and the shape of the groove opening portion, thereby using a radial anisotropic ring magnet even for a motor having a small diameter. At the same time, the drop of the no-load induced voltage can be suppressed to 10% or less, and the 12f component of the torque chopping can be reduced.

10‧‧‧ Stator core

11‧‧‧ teeth

12‧‧‧Flange

13‧‧‧ openings

20‧‧‧Rotor core

30‧‧‧ magnet

A1‧‧‧flat area

A2‧‧‧Migration area

A3‧‧‧Single pole region

Bg‧‧‧Width of the opening of the slot

H‧‧‧ width of the front end

Tw‧‧‧ width of the root

Fig. 1 is a cross-sectional view showing a cross section perpendicular to the axial direction of the permanent magnet type synchronous motor according to the first embodiment of the present invention.

Fig. 2 is an enlarged view of a stator core of a permanent magnet type synchronous motor according to the first embodiment of the present invention.

Fig. 3 is an enlarged view of a rotor core of the permanent magnet type synchronous motor according to the first embodiment of the present invention.

Fig. 4 is a view showing a magnetic flux density waveform when a radial anisotropic ring magnet 30 is used in the permanent magnet type synchronous motor according to the first embodiment of the present invention.

Fig. 5 is a graph showing the relationship between the ratio of the flat area of the single magnetic pole of the first embodiment of the present invention to the ratio of the no-load induced voltage.

Fig. 6 is a graph showing the relationship between the ratio of the flat region of the magnetic flux density waveform of the single magnetic pole of the first embodiment of the present invention and the magnitude of the component of the torque chopping 12f.

Fig. 7 is a cross-sectional view showing a cross section perpendicular to the axial direction of the permanent magnet type synchronous motor according to the second embodiment of the present invention.

Fig. 8 is an enlarged view of a stator core of a permanent magnet type synchronous motor according to a second embodiment of the present invention.

Fig. 9 is a graph showing the relationship of the ratio of the no-load induced voltage to the ratio of the flat region of the single magnetic pole of the second embodiment of the present invention.

Fig. 10 is a view showing a ratio of a flat region of a magnetic flux density waveform of a single magnetic pole when the tip end shape of the permanent magnet synchronous motor according to the second embodiment of the present invention is condition one (h/bg = 1), and torque A diagram showing the size of the chopping 12f component.

Fig. 11 is a view showing a ratio of a flat region of a magnetic flux density waveform of a single magnetic pole when the tip end shape of the permanent magnet synchronous motor according to the second embodiment of the present invention is the condition two (1 < h/bg < 3), and A diagram showing the relationship between the components of the torque chopping 12f.

Fig. 12 is a view showing a ratio of a flat region of a magnetic flux density waveform of a single magnetic pole when the tip end shape of the permanent magnet synchronous motor according to the second embodiment of the present invention is a condition three (3 ≦h/bg), and torque A diagram showing the size of the chopping 12f component.

10‧‧‧ Stator core

11‧‧‧ teeth

12‧‧‧Flange

H‧‧‧ width of the front end

Tw‧‧‧ width of the root

Claims (1)

A permanent magnet type synchronous motor having: Z (Z series natural number) stators formed in a ring shape and having windings; and 2P magnetic poles (P system natural number) permanent magnets, and Z/(3( The value of the phase × 2 P) is 2/5 or 2/7. In the permanent magnet synchronous motor, a radial anisotropic ring magnet is used as the permanent magnet, and a slot opening is formed between the adjacent stator front end portions. The radial anisotropy ring magnet is formed when the width of the front end of the flange portion constituting the distal end portion of the stator is h, the width of the root portion is tw, and the width of the groove opening portion is bg. In the relationship between the flat region of the magnetization waveform and the transition region: (1) when the relationship between the width bg of the groove opening portion and the width h of the tip end portion of the flange portion satisfies h/bg=1, the stator is When the shape satisfies the condition of tw/h=1, the migration region is set and magnetized so that the ratio of the flat region in the single magnetic pole becomes 55% to 95%; the shape of the stator satisfies 1<tw/h< In the case of 3, the ratio of the aforementioned flat regions in a single magnetic pole is 55% to 95%. The transition region is placed and magnetized; and when the shape of the stator satisfies the condition of 3 ≦tw/h, the migration region is set such that the ratio of the flat region in the single magnetic pole is 55% to 80%. (2) When the relationship between the width bg of the groove opening portion and the width h of the tip end portion of the flange portion satisfies 1<h/bg<3, When the shape of the stator satisfies the condition of tw/h=1, the migration region is provided and magnetized so that the ratio of the flat region in the single magnetic pole becomes 55% to 80%; the shape of the stator satisfies 1< In the case of tw/h<3, the migration region is provided and magnetized so that the ratio of the flat region in the single magnetic pole is 55% to 95%; and the shape of the stator satisfies the condition of 3 ≦tw/h. In the case where the ratio of the flat region in the single magnetic pole is 55% to 95%, the transition region is provided and magnetized; and (3) the width bg of the groove opening portion and the width h of the front end portion of the flange portion. When the relationship satisfies 3≦h/bg, when the shape of the stator satisfies the condition of tw/h=1, the transition region is set such that the ratio of the flat region in the single magnetic pole is 55% to 90%. The magnetization; when the shape of the stator satisfies the condition of 1<tw/h<3, the migration region is provided and magnetized so that the ratio of the flat region in the single magnetic pole is 55% to 95%; When the shape of the stator satisfies the condition of 3≦tw/h, The transition region is set to be magnetized in such a manner that the ratio of the flat region in one magnetic pole is 55% to 95%, and the 12f component of the torque ripple is reduced.