JP2016046978A - Concentrated winding permanent magnet synchronous motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concentrated winding permanent magnet synchronous motor capable of reducing cogging torque while keeping an induction voltage.SOLUTION: A stator 14 includes: large teeth 24 around which a coil 28 is wound; and small teeth 26 which are narrower than the large teeth 24 and around which the coil 28 is not wound. A stator magnetic pole pitch θ is set at an angle where a torque component of the large teeth is switched from a plus side to a minus side in any degree component among a plurality of degree components included in the cogging torque of the large teeth 24 and the small teeth 26.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a concentrated winding permanent magnet synchronous motor.

  Conventionally, a concentrated winding permanent magnet synchronous motor is a technology aimed at improving the winding coefficient. The widths of multiple teeth formed on the stator are made unequal alternately, and the winding is wound only on large wide teeth. A structure has been proposed (see, for example, Patent Document 1).

  This structure has a feature that a high winding coefficient can be ensured by widening the pitch of the large teeth around which the winding is wound up to 180 ° in electrical angle, but on the other hand, a plurality of teeth are arranged in the circumferential direction. There is a problem that the cogging torque increases because the magnetic energy change is not constant when the rotor rotates in the circumferential direction because the rotors are alternately arranged at different pitches.

  Further, as a method for reducing the cogging torque, it is known that the curvature of the tip surface of the teeth is made larger than the curvature of the magnetic poles of the rotor to smooth the change in magnetic energy (see, for example, Patent Document 2). . However, when the curvature of the tip surface of the teeth is made larger than the curvature of the magnetic poles of the rotor, the induced voltage tends to decrease.

JP 11-234990 A JP 2005-33941 A

  The present invention has been made in view of the above problems, and an object thereof is to provide a concentrated winding permanent magnet synchronous motor capable of reducing cogging torque while ensuring an induced voltage.

  In order to solve the above-described problem, the concentrated winding permanent magnet synchronous motor according to claim 1 includes a rotor in which a plurality of magnetic poles are arranged in a circumferential direction, a large tooth around which a winding is wound, and the large tooth. A small tooth with a small width and no winding wound thereon are alternately arranged in the circumferential direction, and the large teeth and the small teeth are opposed to the plurality of magnetic poles in the radial direction. The front surfaces of the plurality of magnetic poles in the large teeth and the small teeth, and the surfaces facing the large teeth and the small teeth in the plurality of magnetic poles are formed along the circumferential direction, Stator magnetic pole pitch θ which is an angle formed by a center line passing through the center of the slot located on one side of the large tooth and a center line passing through the center of the slot located on the other side of the one large tooth is One large tooth that is equal to or greater than an angle at which the torque component of the large tooth in any of the plurality of order components included in the cogging torque of the large teeth and the small teeth switches from the plus side to the minus side. Is set to be less than an angle formed by a center line passing through the center of the one small tooth located on one side of the one and a center line passing through the center of the other small tooth located on the other side of the one large tooth. ing.

  According to this concentrated winding permanent magnet synchronous motor, the tip surfaces of the large teeth and the small teeth and the opposing surfaces of the plurality of magnetic poles are formed along the circumferential direction of the rotor and the stator. Accordingly, since the entire tip surfaces of the large teeth and the small teeth can be disposed close to the plurality of magnetic poles, an induced voltage can be ensured.

  Further, the stator magnetic pole pitch θ is set to be equal to or larger than the angle at which the torque component of the large teeth in any one of the plurality of order components included in the cogging torque of the large teeth and the small teeth switches from the plus side to the minus side. Therefore, the cogging torque can be reduced.

  Note that, as described in claim 2, in the concentrated winding permanent magnet synchronous motor according to claim 1, the stator magnetic pole pitch θ may be set to 186 ° ≦ θ <240 ° in electrical angle.

  Further, as described in claim 3, in the concentrated winding permanent magnet synchronous motor according to claim 1 or 2, the stator magnetic pole pitch θ has a torque component of the large teeth in any one of the order components. You may set to the angle which switches from a plus side to a minus side.

  Further, as described in claim 4, in the concentrated winding permanent magnet synchronous motor according to any one of claims 1 to 3, the torque component of the large teeth in any one of the order components is a positive side. Even when the stator magnetic pole pitch θ is set to be equal to or greater than the angle that switches from the negative side to the negative side, the order component that is greater than zero among the plurality of order components does not affect the torque component of the small teeth on the positive side, A pseudo slot may be formed on the leading end surface of the large teeth so that the torque component of the large teeth on the negative side, which is in the opposite phase to the torque component of the small teeth, increases on the negative side.

  According to this concentrated winding permanent magnet synchronous motor, the torque component of the negative large tooth can be increased to the negative side without affecting the torque component of the positive small tooth. It is possible to cancel the torque component of the teeth and the torque component of the negative large tooth.

  Further, as described in claim 5, in the concentrated winding permanent magnet synchronous motor according to claim 4, the torque component of the large teeth in any one of the order components is greater than the angle at which the torque component switches from the plus side to the minus side. Even when the stator magnetic pole pitch θ is set, the torque component of the small teeth on the plus side and the torque component of the large teeth on the minus side cancel each other out of the plurality of order components. In addition, the shape and size of the pseudo slot may be set.

  According to this concentrated winding permanent magnet synchronous motor, since the torque component of the plus side small teeth and the torque component of the minus side large teeth cancel each other out of the plurality of order components, the cogging torque Can be more effectively reduced.

It is a figure which shows the concentrated winding permanent magnet synchronous motor which concerns on one Embodiment of this invention. It is the A section enlarged view of FIG. FIG. 6 is a diagram illustrating a relationship between a stator magnetic pole pitch θ and a cogging torque T. It is a figure which shows the relationship between stator magnetic pole pitch (theta) and cogging torque T, (A) is a 36th order component, (B) is a 72nd order component, (C) is a figure which shows a 108th order component. It is a figure which shows the relationship between the diameter d of a pseudo slot, and the cogging torque T. FIG. It is a figure which shows the relationship between the diameter d of a pseudo slot, and the cogging torque T. FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the motor 10 according to the present embodiment is a concentrated winding permanent magnet synchronous motor, and includes a rotor 12 and a stator 14.

  The rotor 12 includes a cylindrical yoke 16 and a plurality of magnets 18. The plurality of magnets 18 are each formed in an arc shape, and are fixed to the inner surface of the yoke 16. In each magnet 18, an N pole and an S pole are formed side by side in the radial direction of the rotor 12, whereby a plurality of magnetic poles 20 N and 20 S (N Poles and S poles) are alternately arranged in the circumferential direction of the rotor 12.

  The stator 14 is disposed coaxially with the rotor 12 inside the rotor 12, and has an annular main body 22 and a plurality of large teeth 24 and small teeth 26 formed radially on the outer periphery of the main body 22. . The large teeth 24 are wound with the winding 28 in a concentrated manner, and the small teeth 26 are not wound with the winding 28. The small teeth 26 are formed to be narrower than the large teeth 24.

  The large teeth 24 and the small teeth 26 are alternately arranged in the circumferential direction of the stator 14 (same as the circumferential direction of the rotor 12). The plurality of large teeth 24 are formed in the same shape and arranged at an equal pitch. Similarly, the plurality of small teeth 26 are formed in the same shape and arranged at an equal pitch. The large teeth 24 and the small teeth 26 face the plurality of magnetic poles 20N and 20S in the radial direction.

  The tip surfaces 24A, 26A on the side of the plurality of magnetic poles 20N, 20S in the large teeth 24 and the small teeth 26 and the surface 20A (inner surface) facing the large teeth 24 and the small teeth 26 in the plurality of magnetic poles 20N, 20S are rotors. 12 and the stator 14 are formed along the circumferential direction. That is, the tip surfaces 24A and 26A of the large teeth 24 and the small teeth 26 and the facing surfaces 20A of the plurality of magnetic poles 20N and 20S are formed with the same curvature.

  As an example, the motor 10 according to this embodiment has 12 poles and 18 slots, and the plurality of windings 28 are three-phase energized. That is, a current flows through the plurality of windings 28 with a phase difference of 120 ° in electrical angle.

  Further, an angle θ formed by a center line CL1 passing through the center of the slot 30 located on one side of the one large tooth 24 and a center line CL2 passing through the center of the slot 30 located on the other side of the one large tooth 24 is defined. When the stator magnetic pole pitch is used, the stator magnetic pole pitch θ is set as follows.

  That is, first, as shown in FIG. 3, the relationship between the stator magnetic pole pitch θ and the cogging torque T is obtained. The relationship between the stator magnetic pole pitch θ and the cogging torque T is calculated by, for example, computer software. In FIG. 3, the stator magnetic pole pitch θ is indicated by an electrical angle.

  Here, as an example, the stator magnetic pole pitch θ = 168 ° to 204 °. As shown in FIG. 3, the cogging torque T is reduced by increasing the stator magnetic pole pitch θ.

  The cogging torque T includes a plurality of order components. That is, the cogging torque T includes an n-order component that is a natural number n times the least common multiple R of the number P of magnetic poles and the number Q of slots between the large teeth and the small teeth. Since the motor 10 according to the present embodiment has, for example, 12 poles and 18 slots, the cogging torque T includes a 36th natural number n (n = 1, 2, 3,...) That is the least common multiple of 12 and 18. ) Double order components are included.

  In FIGS. 4A to 4C, as an example, when n = 1, 2, 3, that is, for the 36th-order component, the 72nd-order component, and the 108th-order component, the torque component of the large teeth and the small teeth The sum of torque components, the torque component of large teeth, and the torque component of small teeth are shown.

  As shown in FIGS. 4A to 4C, when 186 ° ≦ θ, the torque component of the large teeth in the 36th-order component, the 72nd-order component, and the 108th-order component is switched from the plus side to the minus side. For this reason, the torque component of the large teeth and the torque component of the small teeth are offset, and the total of the torque component of the large teeth and the torque component of the small teeth is reduced.

  In this embodiment, the angle (electrical angle 186 °) at which the torque component of the large teeth in the 36th-order component, the 72nd-order component, and the 108th-order component switches from the plus side to the minus side is set as the stator magnetic pole pitch θ.

  Thus, in the present embodiment, the stator magnetic pole pitch θ is such that the torque component of the large teeth in any one of the plurality of order components included in the cogging torque of the large teeth and the small teeth is changed from the plus side to the minus side. Set to the angle to switch.

  In FIG. 1, the center line CL3 passing through the center of one small tooth 26 located on one side of one large tooth 24 and the center of another small tooth 26 located on the other side of one large tooth 24 are shown. The angle θ1 formed with the passing center line CL4 is 240 ° in electrical angle.

  In the present embodiment, as described above, the stator magnetic pole pitch θ is more preferably an angle (in this case, 186 ° in electrical angle) at which the torque component of the large teeth in any order component switches from the plus side to the minus side. Although set, the angle θ1 formed by the center lines CL3 and CL4 may be set to less than 240 °. That is, in the present embodiment, the stator magnetic pole pitch θ can be arbitrarily set as an electrical angle of 186 ° ≦ θ <240 °.

  By the way, even when the stator magnetic pole pitch θ is set to be equal to or larger than the angle at which the torque component of the large teeth in any of the order components switches from the plus side to the minus side, the order greater than zero among the plurality of order components. Ingredients may be present.

  For example, as shown in FIG. 4A, in the 36th-order component, even when 186 ° ≦ θ is set, the cogging torque T is larger than zero. On the other hand, as shown in FIG. 4B, in the 72nd order component, the cogging torque T becomes zero (minimum) in the vicinity of θ = 195 °. Further, as shown in FIG. 4C, in the 108th-order component, the cogging torque T becomes zero (minimum) in the vicinity of θ = 189 °.

  Therefore, in the present embodiment, in order to reduce the above-described order component (in this case, the 36th-order component) greater than zero, as shown in FIG. 2, a pseudo slot 32 is formed on the front end surface 24A of each large tooth 24. Is done.

  As an example, the pseudo slot 32 is formed by a semicircular cutout, and is formed around the central axis of the large tooth 24. The diameter d of the pseudo slot 32 is set as follows. Hereinafter, a case where the stator magnetic pole pitch θ is set to 198 ° will be described as an example.

  First, as shown in FIG. 5, the relationship between the pseudo slot diameter d and the cogging torque T is obtained. The relationship between the pseudo slot diameter d and the cogging torque T is calculated by, for example, computer software. Here, as an example, the diameter d is 1.05 mm to 1.09 mm. When the diameter d increases from 1.05 mm to 1.07 mm, the cogging torque T decreases, and when the diameter d increases from 1.07 mm to 1.09 mm, the cogging torque T increases. Further, the cogging torque T is minimized at the diameter d = 1.07 mm.

  Further, as shown in FIG. 6, the relationship between the pseudo slot diameter d (0 ≦ d ≦ 1.07) and the cogging torque T is obtained. In FIG. 6, the cogging torque T of the large teeth and the small teeth, the torque component of the large teeth included in the 36th order component of the cogging torque T (hereinafter referred to as the 36th order torque component of the large teeth), and the small teeth A torque component (hereinafter referred to as a 36th-order torque component of small teeth) is shown. The relationship between the pseudo slot diameter d and the cogging torque T is also calculated by computer software, for example.

  As shown in FIG. 6, the 36th-order torque component of the small teeth is substantially constant even if the diameter d increases (does not affect the 36th-order torque component of the small teeth), whereas the 36th-order torque of the small teeth. The 36th-order torque component of the large teeth having the opposite phase to the component increases toward the minus side as the diameter d increases. This is because the pseudo slot 32 (see FIG. 2) becomes a partial magnetic resistance, and by increasing the diameter d of the pseudo slot 32, the 36th-order torque component of the large teeth is increased to the minus side.

  Then, at the diameter d = 1.07 mm of the pseudo slot 32, the value (absolute value) of the 36th-order torque component of the small teeth and the 36th-order torque component of the large teeth, which is the opposite phase, are substantially the same. If the value (absolute value) of the 36th-order torque component of the small teeth and the 36th-order torque component (absolute value) of the large teeth, which is the opposite phase, are approximately the same, the 36th-order torque component of the small teeth and the 36th-order torque component of the large teeth As a result, the cogging torque T is reduced.

  Therefore, in the present embodiment, the 36th-order torque component of the small teeth and the 36th-order torque of the large teeth that are in the opposite phase to each other so that the 36th-order torque component of the small teeth and the 36th-order torque component of the large teeth are offset. The diameter d of the pseudo slot 32 is set to 1.07 mm when the component values (absolute values) are substantially the same.

  As described above, in the present embodiment, even when the stator magnetic pole pitch θ is set to be equal to or larger than the angle at which the torque component of the large teeth in any one of the above-described order components switches from the plus side to the minus side, The order component greater than zero (in this case, the 36th order component) does not affect the torque component of the plus side small teeth, and the minus side torque component of the negative teeth, which is in the opposite phase to the torque component of the small teeth, is minus. The pseudo slot 32 is formed in the front end surface 24A of the large tooth 24 so as to increase to the side.

  Further, the diameter d of the pseudo slot 32 is such that even if the stator magnetic pole pitch θ is set to be greater than the angle at which the torque component of the large teeth in any one of the above-described order components switches from the plus side to the minus side, a plurality of order components In the order component greater than zero (in this case, the 36th-order component), the dimension is set such that the torque component of the plus side small teeth and the torque component of the minus side large teeth cancel each other.

  In the present embodiment, as described above, the diameter d of the pseudo slot 32 is more preferably set to a dimension in which the torque component of the plus side small teeth and the torque component of the minus side large teeth are offset. However, when the width of the distal end surface 24A of the large tooth 24 is d1, the diameter d of the pseudo slot 32 can be arbitrarily set such that 0 <d ≦ d1.

  Next, the operation and effect of this embodiment will be described.

  As described above in detail, in the motor 10 according to the present embodiment, the front end surfaces 24A and 26A of the large teeth 24 and the small teeth 26 and the opposing surfaces 20A (inner side surfaces) of the plurality of magnetic poles 20N and 20S are provided on the rotor 12. And it is formed along the circumferential direction of the stator 14. That is, the tip surfaces 24A and 26A of the large teeth 24 and the small teeth 26 and the facing surfaces 20A of the plurality of magnetic poles 20N and 20S are formed with the same curvature. Therefore, since the entire front end surfaces 24A and 26A of the large teeth 24 and the small teeth 26 can be disposed close to the plurality of magnetic poles 20N and 20S, an induced voltage can be ensured.

  The stator magnetic pole pitch θ is an angle at which the torque component of the large teeth in any one of the plurality of order components included in the cogging torque of the large teeth and the small teeth is switched from the plus side to the minus side (in this case, electric Since the angle is set to 186 ° or more, the cogging torque can be reduced.

  Furthermore, a semicircular pseudo slot 32 is formed on the front end surface 24 </ b> A of the large tooth 24. The diameter d of the pseudo slot 32 is the same as that of the plurality of order components even when the stator magnetic pole pitch θ is set to be greater than the angle at which the torque component of the large teeth in any of the above-described order components switches from the plus side to the minus side. In the order component greater than zero (in this case, the 36th order component), the dimension is set such that the torque component of the plus side small teeth and the torque component of the minus side large teeth cancel each other. Therefore, the cogging torque can be more effectively reduced.

  Next, a modification of this embodiment will be described.

  The motor 10 according to the present embodiment has 12 poles and 18 slots as an example, but may have other numbers of magnetic poles and slots. The number of slots is 3/2 times the number of magnetic poles.

  Further, in the present embodiment, the pseudo slot 32 is formed in a semicircular shape, and the diameter d of the pseudo slot 32 is set to a dimension in which the torque component of the small teeth and the torque component of the large teeth are offset. However, the shape and size of the pseudo slot 32 may be appropriately set so that the torque component of the small teeth and the torque component of the large teeth are offset.

  In the present embodiment, the motor 10 is an outer rotor type in which the rotor 12 is disposed on the radially outer side of the stator 14, but is an inner rotor type in which the rotor 12 is disposed on the radially inner side of the stator 14. May be.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and other various modifications can be made without departing from the spirit of the present invention. It is.

DESCRIPTION OF SYMBOLS 10 ... Motor, 12 ... Rotor, 14 ... Stator, 16 ... Yoke, 18 ... Magnet, 20N, 20S ... Magnetic pole, 20A ... Opposite surface, 22 ... Main part, 24 ... Large teeth, 26 ... Small teeth, 24A, 26A ... Tip surface, 28 ... winding, 30 ... slot, 32 ... pseudo slot

Claims (5)

A rotor in which a plurality of magnetic poles are arranged in the circumferential direction;
The large teeth around which the windings are wound and the small teeth whose width is narrower than that of the large teeth and the windings are not wound are alternately arranged in the circumferential direction, and the large teeth and the small teeth are A stator radially facing the plurality of magnetic poles;
With
The front surfaces of the plurality of magnetic poles in the large teeth and the small teeth, and the facing surfaces of the large teeth and the small teeth in the plurality of magnetic poles are formed along the circumferential direction,
A stator magnetic pole pitch θ that is an angle formed by a center line passing through the center of the slot located on one side of the one large tooth and a center line passing through the center of the slot located on the other side of the one large tooth. ,
One large tooth that is equal to or greater than an angle at which the torque component of the large tooth in any of the plurality of order components included in the cogging torque of the large teeth and the small teeth switches from the plus side to the minus side. Is set to be less than an angle formed by a center line passing through the center of the one small tooth located on one side of the one and a center line passing through the center of the other small tooth located on the other side of the one large tooth. ing,
Concentrated winding permanent magnet synchronous motor. The stator magnetic pole pitch θ is set to 186 ° ≦ θ <240 ° in electrical angle.
The concentrated winding permanent magnet synchronous motor according to claim 1. The stator magnetic pole pitch θ is set to the angle at which the torque component of the large teeth in any one of the order components is switched from the plus side to the minus side.
The concentrated winding permanent magnet synchronous motor according to claim 1 or 2. Even when the stator magnetic pole pitch θ is set to be equal to or greater than the angle at which the torque component of the large teeth in any one of the order components switches from the plus side to the minus side, the order component greater than zero among the plurality of order components. The tip of the large teeth is such that the torque component of the negative large teeth, which is in the opposite phase to the torque component of the small teeth, does not affect the torque component of the small teeth on the positive side, and increases to the negative side. A pseudo slot is formed on the surface,
The concentrated winding permanent magnet synchronous motor as described in any one of Claims 1-3. Even when the stator magnetic pole pitch θ is set to be equal to or greater than the angle at which the torque component of the large teeth in any one of the order components switches from the plus side to the minus side, the order component greater than zero among the plurality of order components. The shape and size of the pseudo slot are set so that the torque component of the small teeth on the plus side and the torque component of the large teeth on the minus side cancel each other.
The concentrated winding permanent magnet synchronous motor according to claim 4.