JP6503540B2 - IPM motor and method of suppressing cogging torque thereof - Google Patents

Description

  The present invention relates to an IPM motor and a method for suppressing the cogging torque, and in particular, for suppressing the cogging torque by using a portion (for example, a through hole) having different reluctance having a reluctance different from that of the rotor. On new improvements.

In the case of a commonly used SPM (Surface Permanent Magnet) motor, a cogging torque can be reduced by appropriately designing the outer shape of the magnet before giving an example of this type of IPM motor conventionally used. Is realized.
On the other hand, as shown in Patent Documents 1 and 2, an IPM (Inter Permanent Magnet) motor is
(A) By appropriately arranging the magnets in the limited volume of the rotor, it is possible to pass more magnet flux to the stator.
(B) The gap can be designed to be narrow because it is not necessary to consider measures to prevent the scattering of magnets.
(C) A large torque can be obtained in a high rotation range by using the field weakening control.
(D) A wide dynamic characteristic can be obtained by the field weakening control.
(E) The eddy current loss of the magnet is small because the magnet is not directly exposed to the flux change of the armature current.
It has begun to be widely used in a wide range of fields due to its advantages.

Unexamined-Japanese-Patent No. 2010-154590 JP 2012-228174 A

Since the conventional IPM motor is configured as described above, the following problems exist.
That is, in the above-described IPM motor, as shown in FIGS. 8 to 10, the outer periphery of the rotor 2 provided on the rotating shaft 1 is formed with the same diameter because it is a perfect circle having an outer diameter of a predetermined radius As shown in FIGS. 9 and 10, the gap is constant at all positions where the magnets 4 of the rotor 2 and the respective projecting magnetic poles 6 (having the stator winding 6A) of the annular stator 5 correspond to circumferential surfaces. Since the gap is extremely small at the same time, many magnetic lines of force are formed and the magnetic flux density is high, so that so-called large cogging torque is generated when the rotor 2 rotates.

Therefore, although it is possible to obtain a large torque type motor as an advantage, the shape of the magnet controls the waveform of the magnetic flux flowing in the gap portion (set extremely narrow as shown) between the projecting magnetic pole 6 and the rotor 2 It is difficult to do this, and the cogging torque tends to be very large by reducing the gap as described above.
That is, although the IPM motor has various advantages over the SPM motor, it has hardly been used as a servomotor that requires positioning accuracy. The major reason is that the cogging torque is too large and the servo control is difficult.

  The present invention has been made to solve the problems as described above, and in particular, by appropriately arranging different portions (for example, through holes) of reluctance having a reluctance different from that of the rotor to the rotor. An object of the present invention is to provide an IPM motor which suppresses cogging torque and a method of suppressing the cogging torque.

An IPM motor according to the present invention comprises an annular stator provided with a plurality of projecting magnetic poles projecting inward at predetermined angular intervals and having a stator winding, and a rotor provided inside the annular stator via a rotation shaft. And a plurality of magnets provided in the rotor, and rotor pole portions formed on the rotor and corresponding to the respective magnets, wherein the rotor is rotated by excitation of the stator winding , In each of the rotor pole portions where the magnet of the rotor is not provided , the first and second portions of one or more magnetic resistances different in magnetic resistance from the rotor are formed, whereby the magnetism is achieved. first of different resistance in IPS motor the rotor cogging torque than no is the configuration that is suppressed second portion, said magnetoresistance Different first portions of circular, polygonal and elliptical or close to the rotor outer peripheral surface of the rotor with either the more the through-hole or recess of shape combining them, second that different said magnetoresistive, The portion is rectangular and the outer peripheral wall thereof is not straight but is arc-shaped along the outer peripheral surface of the rotor and is located between the first portions, and the first and second portions of the magnetic resistance are different from each other. The method for suppressing cogging torque of an IPM motor according to the present invention has a configuration in which the cogging torque of the IPM motor according to the present invention protrudes inward at a predetermined angular interval and has a stator winding. and annular stator having a plurality of protruding poles, a rotor which is provided through a rotating shaft inside the annular stator, and a plurality of magnets provided in the rotor, the rotor Is formed and a rotor pole portion corresponding to the respective magnets, to rotate the rotor by excitation of the stator windings, to each rotor pole section the magnet is not provided in the rotor, By forming one or a plurality of different first and second portions of reluctance different in reluctance from the rotor, the cogging is more than that of the rotor not having the first and second portions different in reluctance. In the method of suppressing cogging torque of an IPM motor in which generation of torque is suppressed, the first portion different in magnetic reluctance is a circle, a polygon and an ellipse, or any one of a through hole or a recess having a shape combining them. And the second portion of the magnetic reluctance , which is located near the rotor outer peripheral surface of the rotor , is rectangular and its outer peripheral wall is straight. And the first and second portions having different magnetic resistances are located inside the rotor outer peripheral surface of the rotor. It is a method that

The IPM motor and the method for suppressing the cogging torque according to the present invention are configured as described above, and therefore the following effects can be obtained.
That is, an annular stator provided with a plurality of projecting magnetic poles projecting inward at a predetermined angular interval and having a stator winding, a rotor provided inside the annular stator via a rotation shaft, and inside the rotor A plurality of magnets provided in the plurality of magnets, and in the IPM motor in which the rotor is rotated by excitation of the stator winding, the rotor and the magnet are magnetic in a region where the magnets of the rotor are not provided. This is shown in FIG. 11 by having a configuration in which generation of cogging torque is suppressed more than that of the rotor by forming one or a plurality of different parts of the magnetic resistance (for example, through holes) having different resistances. As described above, the cogging torque is suppressed and can be used as a servomotor, so that the large torque of the IPM motor can be used to It is possible the deployment of an IPM motor in the product areas that have not been. In addition, it becomes possible to control the suppression of the cogging torque even more. In addition, it is possible to finely adjust the cogging torque of each IPM motor by forming different parts of the magnetic reluctance (for example, through holes) into any of a circle, a polygon and an ellipse, or a shape combining them. .
Further, since the portions having different magnetic resistances are rectangular and the outer peripheral wall thereof is not straight but formed in an arc shape along the outer peripheral surface of the rotor, the volume as the rectangular can be increased as much as possible.

It is a top view which analyzes and shows an IPM motor by the present invention by a finite element method. It is a magnetic flux diagram of the IPM motor of FIG. It is explanatory drawing which shows the magnetic flux density of the IPM motor of FIG. It is an enlarged plan view which analyzes and shows an important section of other forms of Drawing 1 with a finite element method. It is an enlarged view which shows the principal part of FIG. FIG. 5 is a flux diagram of the IPM motor of FIG. 4; It is explanatory drawing which shows the magnetic flux density of the IPM motor of FIG. It is a top view which analyzes and shows the conventional IPM motor by a finite element method. FIG. 9 is a flux diagram of the IPM motor of FIG. 8; It is explanatory drawing which shows the magnetic flux density of the IPM motor of FIG. It is a characteristic view of the cogging torque of the IPM motor of a prior art and this invention.

  The present invention is to suppress cogging torque by using different parts of the magnetic resistance (for example, through holes) in the rotor.

The preferred embodiments of the IPM motor and its cogging torque suppression method according to the present invention will be described below with reference to the drawings.
The same or equivalent parts as in the conventional example will be described with the same reference numerals.
In FIG. 1, reference numeral 5 denotes a ring-shaped stator having a plurality of projecting magnetic poles 6 projecting inward at predetermined angular intervals and having a stator winding 6A. A rotor 2 provided on the shaft 1 is rotatably provided.

  A plurality of magnets 4 are embedded in the rotor 2 on the side of the rotary shaft 1 in the rotor 2, and an outer peripheral surface 2A consisting of the outer diameter of the rotor 2 and an inner peripheral surface consisting of the inner diameter of the annular stator 5 There is a slight gap between 5A and 5A, and the same gap 10A is formed around the entire circumference such that the rotor 2 can rotate.

In the region where the magnet 4 is not formed on the outer peripheral edge 2D of each rotor pole portion 2B of the rotor 2, a first portion (for example, a pair of magnetic resistances different in magnetic resistance from the rotor 2) A circular through hole) 20 is formed, and the different first portion 20 of this magnetic resistance is a circular round hole, but it may be, for example, a polygon and an ellipse not shown, or a shape combining them. It can also be done. Further, in addition to the configuration in which only the air hole is provided, the through hole 20 may be embedded with a groove or a recess, or a substance having a magnetic resistance different from that of the rotor 2. As shown in FIGS. 1 and 4, the rotor pole portion 2B corresponds to the magnet 4. Furthermore, the second portion 20A is located between the first portions 20, 20 as shown in FIG.

By using the through hole 20 (air hole) which is the first portion, the magnetic resistance of this portion is increased, the characteristics of the magnetic flux lines and the magnetic flux density shown in FIG. 11 are improved, and as a result, the cogging torque Will be improved as shown in FIG. Therefore, if it is possible to control the gap magnetic flux density in the gap magnetic flux density waveform and reduce the component of an integral multiple of the least common multiple of the number of magnet poles and the number of stator slots in the waveform of the force of one magnet attracting the stator , Logical cogging due to the shape of the motor is reduced. Therefore, the generation state of the cogging torque can be arbitrarily controlled by selecting the formation position in the rotor 2 of the first portions 20 having different magnetic resistances.

FIG. 4 is an enlarged view of an essential part showing another form of FIG. 1 described above, between the different first portions (for example, through holes) 20 of the respective magnetic resistances in the rotor pole portion 2B of the rotor 2 A more effective configuration can be obtained by forming the second portion 20A of different reluctance having a substantially rectangular shape different from that of FIG.

The outer peripheral wall 20Aa at a position close to the rotor outer peripheral surface 2a of the second portions 20A different in magnetic reluctance is not a straight line, and is formed in an arc shape parallel to the rotor outer peripheral surface 2a. The area is made large, and a larger volume can be secured than in the case of making it linear. The first and second portions 20 and 20A are formed inside the outer peripheral surface 2a and near the outer peripheral surface 2a.

Next, the summary of the IPM motor and the method for suppressing the cogging torque according to the present invention described above is as follows.
That is, an annular stator 5 having a plurality of projecting magnetic poles 6 projecting inward at predetermined angular intervals and having a stator winding 6A, and a rotor provided inside the annular stator 5 via the rotation shaft 1 2, a plurality of magnets 4 provided in the rotor 2, and rotor pole portions 2 B formed on the rotor 2 and corresponding to the magnets 4, the rotor 2 being excited by exciting the stator winding 6 A the then pivot, the said magnet 4 is not provided each rotor pole portions 2B of the rotor 2, the rotor 2 first magnetic reluctance of different different one or plurality of magnetoresistive and, first The formation of the two parts 20 and 20A suppresses the generation of cogging torque more than the rotor 2 which does not have the first and second parts 20 and 20A having different magnetic resistances. In I PM motor has a structure that is, the magnetoresistive different first portion 20 may be circular, polygonal and elliptical or of the rotor 2 along with their become more any combination of the through hole or recess of shape, close to the rotor outer peripheral face 2a, a second portion 20A having the different magnetic resistance, it becomes more rectangular, each with its outer peripheral wall 20Aa is formed in an arc shape along the rotor outer circumferential surface 2a not linear The first and second portions 20 and 20A, which are located between the first portions 20 and 20 and have different magnetic resistances, are located inside the rotor outer peripheral surface 2a of the rotor 2 , and the present invention In the IPM motor and the method of suppressing its cogging torque according to the present invention, an annular stay including a plurality of projecting magnetic poles 6 projecting inward at predetermined angular intervals and having a stator winding 6A And a plurality of magnets 4 provided in the rotor 2 and the rotor winding 2A, and the stator winding 6A is excited by the excitation of the stator winding 6A. the rotor 2 so as to rotate, wherein the said magnet 4 is not provided each rotor pole portions 2B of the rotor 2, the rotor 2 and the first magnetic resistance of different different one or more magnetoresistance , since the second portion 20, 20A are formed, the magnetoresistance of different first, the I PM motor cogging torque than without the rotor 2 and the second portion 20, 20A is that is suppressed the method suppressing the cogging torque, the magnetoresistive different first portion 20 may be circular, polygonal and elliptical or ne more either through hole or recess having a shape combining them, Close to the rotor 2 the rotor outer circumferential surface 2a with the second portion 20A of different magnetic resistance, it becomes more rectangular outer peripheral wall thereof 20Aa is formed in an arc shape along the rotor outer circumferential surface 2a not linear And the first and second portions 20 and 20A having different magnetic resistances located between the respective first portions 20 and 20 are located inside the rotor outer peripheral surface 2a of the rotor 2 .

  The IPM motor and the method for suppressing the cogging torque according to the present invention form a change in gap magnetic flux density in the circumferential direction by forming a different portion of magnetic reluctance which is a portion different from the reluctance of the rotor pole rotor of the rotor. Fine control can be performed to suppress and reduce cogging torque, and servo control of the IPM motor can be realized.

DESCRIPTION OF SYMBOLS 1 rotating shaft 2 rotor 2a rotor outer peripheral surface 2A outer peripheral surface 2B rotor pole part 2D outer periphery 4 magnet 5 ring shaped stator 5A inner peripheral surface 5E inner wall surface 6 protruding magnetic pole 6A stator winding 6B straight surface part 6C arc part 6Ba curved surface part 10 Gap part 10A Gap 20, 20A First and second parts of different magnetoresistance (through holes)

Claims (2)

An annular stator (5) provided with a plurality of projecting magnetic poles (6) projecting inward at predetermined angular intervals and having a stator winding (6A); and a rotating shaft (1) inside the annular stator (5) ), A plurality of magnets (4) provided in the rotor (2), and rotor poles formed on the rotor (2) corresponding to the respective magnets (4). A rotor (2B), the rotor (2) is rotated by excitation of the stator winding (6A), and each of the rotor poles is provided with the magnet (4) of the rotor (2). In a portion (2B), in a region other than between each magnet (4) and the rotor outer peripheral surface (2a), one or a plurality of magnetic resistances different in magnetic resistance from the rotor (2) And the second portion (20, 20A) is formed, so that the rotor (2) does not have the first and second portions (20, 20A) having different magnetic resistances. In the IPS motor having a configuration in which the occurrence of cogging torque is suppressed, the first portion (20) having a different magnetic resistance is any of a through hole or a recess having a circular shape, a polygonal shape, an elliptical shape, or a combination thereof. The second portion (20A) of the second magnetic reluctance portion is located near the rotor outer peripheral surface (2a) of the rotor (2) and has a rectangular shape, and the outer peripheral wall (20Aa) is not straight. The first and second portions (20, 20A) of the magnetic resistance which are formed in an arc shape along the rotor outer peripheral surface (2a) and located between the respective first portions (20, 20) IPM motor located inside the rotor outer peripheral surface (2a) of the rotor (2). An annular stator (5) provided with a plurality of projecting magnetic poles (6) projecting inward at predetermined angular intervals and having a stator winding (6A); and a rotating shaft (1) inside the annular stator (5) ), A plurality of magnets (4) provided in the rotor (2), and rotor poles formed on the rotor (2) corresponding to the respective magnets (4). A rotor (2B), the rotor (2) is rotated by excitation of the stator winding (6A), and each of the rotor poles is provided with the magnet (4) of the rotor (2). The first part of one or a plurality of magnetic resistances having different magnetic resistances from the rotor (2) in the region (2B) other than between the magnets (4) and the rotor outer peripheral surface (2a) By forming the second portion (20, 20A), the rotor (2) which does not have the first and second portions (20, 20A) having different magnetic resistances is more effective than the rotor (2). In the method of suppressing cogging torque of an IPM motor in which generation of a torque is suppressed, the first portion (20) having different magnetic resistances is a through hole or a recess having a circular shape, a polygonal shape, an elliptical shape, or a combination thereof. The second portion (20A) of any of the above and located near the rotor outer peripheral surface (2a) of the rotor (2) and different in magnetic resistance is rectangular and its outer peripheral wall (20Aa) is a straight line The first and second portions (20, 20A) having different magnetic resistances are formed in an arc shape along the rotor outer peripheral surface (2a) and located between the respective first portions (20, 20). A method for suppressing cogging torque of an IPM motor, characterized in that the method is located inside the rotor outer peripheral surface (2a) of the rotor (2).

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