JP3428769B2 - Synchronous motor rotor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor magnetic piece formed of a high magnetic permeability material and having a magnetic reluctance distribution in the circumferential direction, and a rotor magnetic pole is formed in a low magnetic reluctance portion so that the rotor magnetic pole is formed in a rotating magnetic field. The present invention relates to a rotor of a synchronous motor that rotates around a rotation axis.

[0002]

2. Description of the Related Art As shown in FIG. 15, a conventional two-pole synchronous motor has U-phase windings UP, UN, V-phase windings VP, VN,
A rotating magnetic field is formed in the stator 27 by the three-phase alternating current such as the W-phase windings WP and WN, and the salient-pole rotor 53 is rotated about the rotation axis.

FIG. 14 shows a circuit configuration of a control circuit for controlling a synchronous motor (see Japanese Patent Laid-Open No. 60-96190). In this synchronous motor, the position detector 54 detects the position of the rotor 53, and the position signal D of the rotor 53 is detected.
Based on S, the magnitude of the current flowing through the stator 27 is servo-controlled.

The speed detection circuit 56 produces a speed signal SD based on the position signal DS. The speed signal SD is matched with the target speed command SI, and the adder 51 obtains the speed deviation ES. The speed deviation ES is subjected to compensation calculation such as proportionality / integration / derivation by the speed control means 57 to obtain a torque command T.

The armature current command circuit 58 has a torque command T
And three-phase armature current commands SAIU, SAIV, SA based on the rotor rotation angle RP from the rotor position detection circuit 55.
IW is output. Each armature current command SAIU, SAI
V and SAIW are represented by SAIU = SA × COS (RP) SAIV = SA × COS (RP + 120 °) SAIW = SA × COS (RP + 240 °), where SA is the amplitude.

These armature current commands SAIU, SAI
Three-phase field current commands SFIU, SFIV, SFIW are added to V and SAIW in adders 72, 73, 74, and three-phase current commands SIU, SIV, SIW are output to the current control circuit 60. Field current command SFIU, SFI
V and SFIW are created and output by the field command current circuit 59 based on the rotor rotation angle RP from the rotor position detection circuit 55 and the speed signal SD. The field current command SFIU, SFIV, SFIW is the field current command SF
Then, SFIU = SF × SIN (RP) SFIV = SF × SIN (RP + 120 °) SFIW = SF × SIN (RP + 240 °)

The current control circuit 60 uses a three-phase current command SI.
U, SIV, SIW are power-amplified, and drive currents IU, IV, IW are supplied to the three-phase windings U, V, W of the synchronous motor.

During operation, the components of the three-phase field current command always operate so as to form a field magnetic flux in the magnetic pole direction of the rotor, and the components of the three-phase armature current command are orthogonal to and intersect this magnetic flux. Flow to. At this time, according to Fleming's law, F =
A force proportional to the vector product of B × I × L is generated, and a motor rotation torque is obtained. Here, B is a vector of the field magnetic flux density, I is a vector having a value proportional to the amplitude SA of the armature current command, and L is the effective winding portion of the three-phase winding of the synchronous motor that intersects with the magnetic flux. It is a value proportional to the total extension. The rotation torque has a value proportional to a value obtained by multiplying the cosine of the direction of the vector product F and the rotation direction.

By such an operation, forward and reverse torque can be freely obtained, and precise speed control of the synchronous motor can be realized.

Generally, in various electric motors, the occurrence of pulsating torque in which the electric motor rotating torque periodically pulsates often poses a problem. For example, when a synchronous motor having a pulsating torque is used for the feed shaft of a machine tool, it becomes difficult to keep the cutting force of the tool constant. As a result, undulation occurs on the surface of the work piece and accuracy is impaired.

In order to reduce this pulsating torque, in a permanent magnet type synchronous motor in which a permanent magnet is used for the rotor, the rotor is equally divided into a plurality of rotor blocks in the rotation axis direction, and each rotor block is arranged in the rotation direction. They were coupled in the direction of the rotation axis with a constant central angle shifted (Japanese Patent Laid-Open No. 4-211).
No. 330). The pulsating torque is canceled by the deviation of the constant center angle.

[0012]

In a permanent magnet type synchronous motor using permanent magnets in the rotor magnetic poles, each part of the permanent magnet has a magnetomotive force, and the magnetic flux is less biased. As a result, as described above, it is possible to easily reduce the pulsating torque only by coupling the plurality of rotor blocks by shifting them by a constant center angle in the rotation direction.

However, in the case of a reluctance synchronous motor in which the rotor is made of a high magnetic permeability material and the magnetic poles are formed by the field current, the magnetic flux crosses between the rotor blocks in the direction of the rotation axis and the magnetic resistance is low. Since it is biased to one side, the waveform of the pulsating torque generated in each rotor block differs. As a result, the pulsating torque cannot be canceled even if the rotor blocks are coupled while being displaced by a constant central angle in the rotational direction.

The present invention has been made under the above circumstances, and an object thereof is to provide a rotor of a synchronous motor capable of reducing pulsating torque with a simple structure.

[0015]

In order to achieve the above object, a first aspect of the present invention is to laminate rotor pieces made of a high magnetic permeability material and having a magnetic resistance distribution in the circumferential direction, to obtain a low magnetic resistance. In a rotor of a reluctance synchronous motor that forms a rotor magnetic pole in a portion and rotates around a rotation axis in a rotating magnetic field, the rotor is divided into a plurality of rotor blocks in the rotation axis direction, and each rotor block has a pulsating torque in the rotation direction . 1/2 cycle
Which are coupled to each other in the direction of the rotation axis with a constant center angle offset, and between the rotor blocks made of the high magnetic permeability material, a magnetic insulating member for preventing the magnetic flux from flowing to the rotor blocks having a low magnetic resistance is sandwiched and fixed. It is characterized by

According to a second aspect of the present invention, rotor pieces made of a material having a high magnetic permeability and having a magnetic resistance distribution in the circumferential direction are laminated, and a rotor magnetic pole is formed in a low magnetic resistance portion to form a rotating shaft in a rotating magnetic field. In a rotor of a reluctance synchronous motor rotating around, a basic magnetic pole arranged at a uniform center angle corresponding to the number of poles of a rotor magnetic pole, and a constant center corresponding to 1/2 cycle of pulsating torque from the uniform center angle. It is arranged at a position shifted in the direction of rotation by an angle , the same number as the basic magnetic poles, and
It is characterized in that it is provided with offset magnetic poles arranged to each other .

[0017] A third invention is laminated rotor segment having a magnetoresistive circumferentially distributed consists of high magnetic permeability material, the rotational shaft in a rotating magnetic field to form a rotor pole in the low reluctance portion In a rotor of a reluctance synchronous motor that rotates around, a basic magnetic pole having a predetermined width and a predetermined width
The width of the constant center angle corresponding to 1/2 cycle of the pulsating torque is
Characterized by having increased magnetic poles .

[0018] The fourth invention is the rotor according to claim 1, wherein the reluctance synchronous motor, characterized in that it is combined with the skewed rotor blocks to the rotation axis.

[0019]

According to the first aspect of the present invention, the pulsating torques generated in the rotor block are offset from each other, and as a result, the pulsating torque is reduced. Since the magnetic insulating member is interposed between the rotor blocks, the magnetic flux of the rotor block does not escape to another rotor block having a small magnetic resistance. Therefore,
The pulsating torque is reliably reduced.

Further, according to the second aspect of the invention, since the offset magnetic pole is arranged at a position deviated from the uniform central angle corresponding to the number of poles of the rotor magnetic pole by a constant central angle, the pulsating torque is generated between the offset magnetic pole and the basic magnetic pole. Cancel each other out. Therefore, the pulsating torque is reduced.

Further, according to the third aspect of the invention, since the width of a part of the rotor magnetic poles is increased in the rotational direction, the pulsating torque is canceled out between this magnetic pole and the other magnetic poles, and the pulsating torque is reduced. .

Furthermore, according to the fourth aspect, the pulsating torques generated in the rotor block are offset from each other, and as a result, the pulsating torque is reduced. Since the magnetic insulating member is interposed between the rotor blocks, the magnetic flux of the rotor block does not escape to another rotor block having a small magnetic resistance. Therefore, the pulsating torque is reliably reduced.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows the overall construction of a four-pole rotor according to the first embodiment of the present invention. This rotor is divided into a plurality of rotor blocks 102 and 103 in the rotation axis direction.
Each rotor block is formed by laminating rotor pieces made of a high magnetic permeability material and having a magnetic resistance distribution in the circumferential direction. The rotor blocks 102 and 103 are coupled in the rotational axis direction with a constant center angle 104 displaced in the rotational direction. A magnetic insulating member 121 is sandwiched and fixed between the rotor blocks.

If the constant central angle 104 between the rotor blocks 102 and 103 is set to 1/2 of the cycle of the pulsating torque generated by the harmonics, the pulsating torques generated by the rotor blocks cancel each other out to minimize the pulsating torque. You can keep it to the limit. For example, as shown in FIG. 2, the torque generated in the rotor block 102 shows a pulsation like a solid line 105 according to the rotation angle of the rotor, and the torque generated in the rotor block 103 deviated by a certain center angle is like a solid line 106. Shows pulsation. As a result, the pulsating torque is canceled out, and a substantially constant total torque 107 is obtained.
Moreover, the magnetic insulating member 121 prevents the magnetic flux from flowing between the rotor blocks 102 and 103, so that the magnetic flux does not move to the portion having a low magnetic resistance by moving in the rotation axis direction. Since the rotor is formed by laminating rotor pieces, the rotor can be easily divided in the rotation axis direction.

FIG. 3 shows a piece 105 of a four-pole rotor of a synchronous motor having particularly low pulsating torque. This piece 10
5 is formed by pressing a disc-shaped high magnetic permeability material. A plurality of subdivided magnetic paths 107 extending from the magnetic pole 101 to the magnetic pole 101 are formed in the element piece 105 symmetrically with respect to two diameter lines 106 that are orthogonal to each other. Between the adjacent magnetic paths 107, the magnetic insulating portion 108 is made of air or a material having a large magnetic resistance. Each magnetic path 107 has a connecting portion 1 near the center from the magnetic pole 101 to the magnetic pole 101.
No. 09 is produced, but this structure is effective for securing the strength of the rotor structure and making the magnetic flux distribution in the outer peripheral portion of the rotor uniform. According to such a rotor structure, it is possible to generate a field distribution close to a sine wave, which is difficult to obtain with an extreme rotor salient pole structure, and therefore a relatively small pulsating torque characteristic is exhibited.

4 to 7 show a rotor of a synchronous motor according to a second embodiment of the present invention, which can reduce the pulsating torque due to two harmonics. In the second embodiment, as shown in FIG.
As shown in, the rotor is evenly divided into four rotor blocks 112 to 115 in the rotation axis direction. As shown in FIG. 5, the two rotor blocks 112 and 113 have a constant center angle 11 corresponding to a half cycle of the first harmonic in the rotation direction.
Cancel block 1 that is coupled to each other with a shift of 6
Make up 17. Similarly, the other two rotor blocks 1
As shown in FIG. 6, 14 and 115 are coupled to each other while being offset from each other by a constant central angle 116 that corresponds to a half cycle of the first harmonic, and form a cancel block 118. Finally, as shown in FIG. 7, the cancel blocks 117 and 118 are moved relative to the rotational direction by 1 / second of the second harmonic.
They are coupled by shifting by a constant center angle 119 corresponding to two cycles. With such a configuration, the pulsating torque due to the two harmonics is reduced, and the electric motor rotating torque is kept substantially constant.
The magnetic insulating member 1 is provided between the rotor blocks 112 to 115.
Reference numeral 21 blocks the flow of magnetic flux between the rotor blocks. In this way, the pulsating torque due to a plurality of harmonics can also be reduced by increasing the number of divisions of the cancel block and combining them.

FIG. 8 shows a four-pole rotor according to the third embodiment of the present invention. In the third embodiment, the basic magnetic poles 133 and 134 are arranged with a uniform central angle (90 degrees in this case) corresponding to the number of rotor poles, and a constant central angle 136 from the central angle.
It is characterized by comprising offset magnetic poles 131 and 132 arranged at offset positions.

Assuming that the magnetic poles of the rotor are arranged at equal center angles corresponding to the number of rotor poles, the amplitude, frequency, and phase of the pulsating torque generated by the magnetic poles of the rotor are the same. Here, as shown in FIG. 8, when the deviation magnetic poles 131 and 132 are provided at positions deviated in the rotational direction by a constant center angle 136 corresponding to 1/2 cycle of the pulsation torque, the pulsation torque and the basic magnetic pole of the deviation magnetic poles 131 and 132 are provided. 133,
The pulsating torques of 134 cancel each other out, and the total torque is kept substantially constant.

FIG. 9 shows a four-pole rotor according to the fourth embodiment of the present invention. This four-pole rotor 141 has a rotor magnetic pole 1
It is characterized in that the widths of 45 and 146 are increased by a constant center angle 149. In this case, the constant center angle 149
Corresponds to 1/2 cycle of the pulsating torque, that is, 1/2 cycle of the slot pitch.

Generally, the slots 143 of the stator 142 are
The pulsating torque due to the magnetic resistance difference between the tooth 144 and the tooth 144 is caused by the reversal of the magnetic resistance difference force when the magnetic pole end of the rotor 141 passes through the center of the slot 143 of the stator 142 and the tooth 144. According to the configuration of the fourth embodiment, when the magnetic resistance difference forces of the magnetic poles 145 and 146 and the magnetic poles 147 and 148 are reversed, they act to cancel each other, so that the sum generation torque is kept substantially constant.

10 to 13 show a four-pole rotor according to the fifth embodiment of the present invention. A technique for reducing the pulsating torque including two harmonics by arbitrarily combining the pulsating torque reducing technique shown in the first to third embodiments and the conventional technique for skewing the rotating shaft to reduce the pulsating torque. This is an example.

As shown in FIG. 10, the rotor is equally divided into a plurality of rotor blocks 151 and 152. Subsequently, as shown in FIGS. 11 and 12, each rotor block 15
1, 152 are skewed by an angle 153 corresponding to one cycle of the first harmonic. Finally, as shown in FIG. 13, the skewed rotor blocks 151 and 152 are moved to the second direction in the rotation direction.
They are coupled to each other with a constant center angle 154 corresponding to a half cycle of the higher harmonic wave. Rotor blocks 151, 152
A magnetic insulating member 155 is sandwiched between them. The pulsating torque due to the two harmonics is reduced, and the sum generation torque is kept substantially constant. Similar to the first embodiment described above, the pulsating torque due to a plurality of harmonics is also reduced by combining the cancel blocks. Even if the stator is skewed instead of the rotor, the pulsating torque can be similarly reduced.

In the above embodiments, a four-pole rotor has been described, but the present invention can be similarly applied to other than four-pole rotors. Also, the three-phase AC motor was explained,
It is also possible to apply the present invention to a polyphase AC motor.

[0035]

As described above, according to the first aspect of the present invention, the pulsating torques generated in the rotor blocks cancel each other out, and as a result, the pulsating torque is reduced. Since the magnetic insulating member is interposed between the rotor blocks, the magnetic flux of the rotor block does not escape to another rotor block having a small magnetic resistance. Therefore, the pulsating torque is reliably reduced with a simple structure.

Further, according to the second aspect of the invention, since the offset magnetic pole is arranged at a position deviated from the uniform central angle corresponding to the number of poles of the rotor magnetic pole by a constant central angle, the pulsating torque is generated between the offset magnetic pole and the basic magnetic pole. Cancel each other out. Therefore, the pulsating torque is reduced with a simple structure.

Further, according to the third aspect of the invention, since the width of a part of the rotor magnetic poles is increased in the rotational direction, the pulsating torque is canceled out between this magnetic pole and the other magnetic poles, and the pulsating torque is simplified with a simple structure. Is reduced.

Furthermore, according to the fourth aspect of the present invention, the pulsating torques generated in the rotor block are offset from each other, and as a result, the pulsating torque is reduced. Since the magnetic insulating member is interposed between the rotor blocks, the magnetic flux of the rotor block does not escape to another rotor block having a small magnetic resistance. Therefore, the pulsating torque is reliably reduced with a simple structure.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a rotor of a synchronous motor according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a rotor rotation angle of a synchronous motor and generated torque.

FIG. 3 is a diagram showing a rotor element of a 4-pole rotor of a synchronous motor.

FIG. 4 is a diagram showing a rotor block that constitutes a rotor of a synchronous motor according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a cancel block including a rotor block.

FIG. 6 is a diagram showing a cancel block composed of a rotor block.

FIG. 7 is a diagram showing a rotor configured by combining cancel blocks.

FIG. 8 is a diagram showing a rotor of a synchronous motor according to a third embodiment of the present invention.

FIG. 9 is a diagram showing a rotor and a stator of a synchronous motor according to a fourth embodiment of the present invention.

FIG. 10 is a diagram showing a rotor block that constitutes a rotor of a synchronous motor according to a fifth embodiment of the present invention.

FIG. 11 is a diagram showing a skew block including a rotor block.

FIG. 12 is a diagram showing a skew block including a rotor block.

FIG. 13 is a diagram showing a rotor configured by combining skew blocks.

FIG. 14 is a circuit configuration diagram showing a control circuit of a synchronous motor.

FIG. 15 is a diagram showing a rotor of a synchronous motor according to a conventional technique.

[Explanation of symbols]

101 magnetic poles, 102, 103 rotor blocks, 10
5 rotor element, 121 magnetic insulating member, 141 rotor, 142 stator.

Continuation of front page (56) Reference JP 61-161985 (JP, A) JP 54-1113812 (JP, A) JP 6-153428 (JP, A) JP 1-318579 (JP , A) Actual Development Sho 63-191864 (JP, U) Japanese Patent Sho 30-3878 (JP, B1) Actual Public Sho 49-21525 (JP, Y1) (58) Fields investigated (Int.Cl. ⁷ , DB) Name) H02K 19/10 H02K 1/24 H02K 15/02 H02P 7/05

Claims (4)

(57) [Claims] 1. A rotor element composed of a high-permeability material and having a magnetic resistance distribution in the circumferential direction is laminated, and a rotor magnetic pole is formed in a low magnetic resistance portion to rotate around a rotation axis in a rotating magnetic field. In a reluctance synchronous motor rotor, the rotor is divided into a plurality of rotor blocks in the rotation axis direction,
The rotor blocks are coupled in the rotational axis direction with a constant center angle corresponding to 1/2 cycle of the pulsating torque in the rotational direction, and the rotor blocks having a high magnetic permeability have low magnetic resistance. A rotor for a synchronous motor, characterized in that a magnetic insulating member that blocks the flow of magnetic flux to and from is fixed. 2. A rotor element composed of a material having a high magnetic permeability and having a magnetic resistance distribution in the circumferential direction is laminated, and a rotor magnetic pole is formed in a low magnetic resistance portion to rotate around a rotation axis in a rotating magnetic field. a rotor for a reluctance synchronous motor, the basic magnetic poles arranged in equal center angle corresponding to the number of poles of the rotor poles, a constant central angle by the rotation direction corresponding to 1/2 period of the pulsation torque from the equal central angle disposed offset position, the
A rotor for a synchronous motor, comprising: the same number of basic magnetic poles and offset magnetic poles arranged alternately with the basic magnetic poles . 3. A rotor element composed of a high magnetic permeability material and having a magnetic resistance distribution in a circumferential direction is laminated, and a rotor magnetic pole is formed in a low magnetic resistance portion to rotate around a rotation axis in a rotating magnetic field. In a rotor of a reluctance synchronous motor, a basic magnetic pole having a predetermined width and a magnetic pole having a width increased by a constant center angle corresponding to 1/2 cycle of pulsating torque from the predetermined width are provided. Rotor. 4. The rotor of claim 1, 2 or <br/> according to any one of the three reluctance synchronous motor, synchronous motor, characterized in that it is combined with the skewed rotor blocks to the rotation axis Rotor.