JP2006304546A - Permanent magnet reluctance type rotary electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a permanent magnet reluctance type rotary electric machine which reduces a maximum value of an induced voltage waveform and a torque ripple generated by a rotary electric machine. <P>SOLUTION: The permanent magnet reluctance type rotary electric machine includes a stator 1 having an armature coil 4, a rotor 2 rotatably provided inside the stator 1 and having a rotor core 7a, and a permanent magnet 12 arranged in the rotor core 7a so that a magnetic flux from the armature coil 4 passing between magnetic poles 14 of the core adjacent to the rotor 2 may be negated. The rotor 2 is divided into two parts in a rotating shaft direction, and the divided rotors 2 are shifted and arranged in a circumferential direction. Supposing that an angle formed by a magnetic pole center of the core 7a of one divided rotor and the magnetic pole center of the core 7a of the other divided rotor with a rotating shaft is a skew angle θ, the skew angle θ is 13°<θ<31°. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a permanent magnet type reluctance type rotating electrical machine, and more particularly to a structure for reducing induced voltage and torque pulsation generated from the rotating electrical machine.

  2. Description of the Related Art Conventionally, a permanent magnet motor using a permanent magnet as a field magnet is known as a high-efficiency motor used for driving a vehicle such as a hybrid vehicle or an electric vehicle. As a typical permanent magnet motor, a surface magnet type permanent magnet motor in which a permanent magnet is attached to the outer periphery of a rotor core and an embedded type permanent magnet motor in which a permanent magnet is embedded in the rotor core are known.

  Further, as a high-output motor excellent in variable characteristics, a permanent magnet type reluctance type rotating electrical machine using both reluctance torque and magnet torque is known (for example, Patent Document 1). An embedded permanent magnet motor and a permanent magnet type reluctance type rotating electrical machine are suitable for variable speed driving such as vehicle driving.

  In particular, the permanent magnet type reluctance type rotating electrical machine uses a reluctance torque that can obtain a torque equal to or higher than the magnet torque, together with the magnet torque. It is driven by magnet torque, and is driven mainly by reluctance torque during high-speed rotation. Therefore, high output and wide variable speed operation is possible.

  FIG. 8 is a circumferential sectional view of a conventional permanent magnet type reluctance type rotating electrical machine. As shown in FIG. 8, the stator 1 of this permanent magnet type reluctance type rotating electrical machine has a stator core 3 and an armature winding 4, and a rotor 2 is provided inside the stator 1. . The rotor 2 includes a magnet embedding hole 13 formed in a substantially V shape in the circumferential direction and a permanent magnet 12 disposed in the magnet embedding hole 13, and has a magnetic pole formed by the permanent magnet 12 and an iron core magnetic pole 14. is doing. Further, in the rotor core 7 of the conventional permanent magnet type reluctance type rotating electrical machine shown in FIG. 8, a triangular hole 100 which is a nonmagnetic portion is formed between the magnetic pole 14 of the iron core and the magnetic pole 14 of another adjacent iron core. Has been.

  However, in a motor using such a permanent magnet, an induced voltage is generated in the rotating electrical machine when the rotor 2 is rotated by an external force. Due to this induced voltage, an overvoltage is applied to the energizing circuit or the control circuit, which may destroy the energizing circuit or the control circuit. Therefore, a motor using a permanent magnet needs to be designed so that the induced voltage is less than the withstand voltage of the energization circuit and the control circuit.

Therefore, an embedded permanent magnet motor is disclosed in which the induced voltage waveform is approximated to a sine wave in order to suppress the induced voltage of the permanent magnet motor (Patent Document 2). FIG. 9 is a circumferential sectional view showing one pole pair of an embedded permanent magnet motor (three-phase eight poles, 48 slots) in which the induced voltage waveform is approximated to a sine wave. As shown in FIG. 9, this embedded permanent magnet motor is arranged with a stator 101 having an armature winding 104 and a gap 109 in the stator 101, and a plurality of permanent magnets 112 are embedded in the circumferential direction. And the rotor 102. This embedded permanent magnet motor approximates the waveform of the induced voltage to a sine wave by adjusting the side of the permanent magnet 112 on the stator 101 side, that is, the angle φ formed by the outer peripheral surface width with respect to the axis. It suppresses the peak value. FIG. 10 shows an induced voltage waveform when the permanent magnet width angle φ is 24, 26, and 28 degrees. As shown in FIG. 10, when the permanent magnet width angle φ is 26 degrees, the induced voltage waveform is shown in FIG. The peak value becomes smaller.
JP-A-11-136912 Japanese Patent Laid-Open No. 10-146031

  However, when the conventional permanent magnet type reluctance type rotating electrical machine shown in FIG. 8 is used, for example, for driving a vehicle such as a hybrid vehicle, it is further reduced in size, increased in torque and output in order to improve the driving performance of the vehicle. Is required. In order to achieve miniaturization and high output, high-speed rotation of a rotating electrical machine is necessary. However, the induced voltage generated from the rotating electrical machine increases as the rotational speed increases.

  In addition, in a hybrid vehicle or the like, there is a great restriction on the drive unit space, and a flat type rotating electric machine having a very small axial dimension is required, so that the axial dimension of the armature winding 4 can be reduced. A winding type rotating electrical machine is used. However, in the concentrated winding method, the induced voltage generated by the permanent magnet magnetic flux is greatly distorted and the maximum value of the induced voltage waveform is higher than that of the normally used distributed winding method. Furthermore, the concentrated winding method has a large torque pulsation, and the torque is not effectively utilized. Therefore, the output is reduced, and electromagnetic vibration and noise are generated.

  Therefore, in the conventional permanent magnet type reluctance type rotating electric machine shown in FIG. 8, there is a possibility that the energization circuit or the control circuit may be destroyed by the overvoltage caused by the induced voltage, and therefore the induced voltage needs to be further reduced. However, the peak value of the induced voltage waveform cannot be sufficiently suppressed only by approximating the induced voltage waveform to a sine wave as in the embedded permanent magnet motor shown in FIG. In addition, there is a problem that torque pulsation cannot be reduced.

  An object of the present invention is to provide a permanent magnet type reluctance type rotating electrical machine that can reduce the maximum value and torque pulsation of an induced voltage waveform to be generated, and can be reduced in size, high speed rotation, high torque, low vibration and low noise. There is.

  The present invention employs the following means in order to solve the above problems. According to a first aspect of the present invention, there is provided a stator having an armature winding, a rotor provided rotatably inside the stator, and having a rotor iron core, and passing between the magnetic poles of the iron core adjacent to the rotor. A permanent magnet type reluctance type rotating electrical machine including a permanent magnet disposed in the rotor core so as to cancel the magnetic flux from the armature winding, wherein the rotor is divided into two in the rotation axis direction. The divided rotors are arranged shifted in the circumferential direction, and the angle formed by the magnetic pole center of one of the divided rotor cores and the magnetic pole center of the other divided rotor core is skewed with respect to the rotation axis. When the angle θ is set, the skew angle θ is 13 degrees <θ <31 degrees.

  According to a second aspect of the present invention, in the permanent magnet reluctance type rotating electric machine according to the first aspect, the stator has a stator tooth that is a convex portion protruding to the inner surface, and the center of the magnetic poles of two adjacent iron cores. The angle γ formed by the width of the tip of the inner diameter surface of the stator teeth with respect to the rotation axis with respect to the angle β formed by the line with respect to the rotation axis is 0.56 × β <γ <0.65 × β It is characterized by being.

  According to a third aspect of the present invention, in the permanent magnet type reluctance type rotating electrical machine according to the first or second aspect, the width w of the permanent magnet is in relation to the number of poles P of the rotor and the outer diameter Dr of the rotor. (1.5 × Dr) / (2 × P) <w <(2.2 × Dr) / (2 × P).

  According to a fourth aspect of the present invention, in the permanent magnet type reluctance type rotating electric machine according to any one of the first to third aspects, a space between magnetic poles of the adjacent iron cores is filled with an iron core. .

  According to a fifth aspect of the present invention, in the permanent magnet reluctance type rotating electric machine according to any one of the first to fourth aspects, the stator has a stator slot that houses the armature winding, The number of stator slots is ½ of a predetermined number of stator slots per pole per phase.

  According to a sixth aspect of the present invention, in the permanent magnet type reluctance type rotating electric machine according to any one of the first to fifth aspects, the armature winding is configured by concentrated winding.

  According to the first aspect of the present invention, the rotor is divided into two in the direction of the rotation axis, the divided rotors are arranged shifted in the circumferential direction, and are divided from the magnetic pole center of one of the divided rotor cores. The angle formed by the magnetic pole center of the other rotor core with respect to the rotation axis is the skew angle θ, and the skew angle θ is set to 13 degrees <θ <31 degrees. Therefore, the induction generated from the permanent magnet type reluctance type rotating electrical machine The maximum value of the voltage waveform and the torque pulsation can be reduced, and the rotating electrical machine can be reduced in size, rotated at a high speed, increased in torque, reduced in vibration and noise.

  According to the invention of claim 2, the angle γ formed by the width of the tip of the inner diameter surface of the stator teeth with respect to the rotation axis is set to the angle β formed by the center line of the magnetic poles of two adjacent iron cores with respect to the rotation axis On the other hand, since 0.56 × β <γ <0.65 × β, the torque pulsation can be further reduced.

  According to the invention of claim 3, the width w of the permanent magnet is set to (1.5 × Dr) / (2 × P) <w <(with respect to the number of poles P of the rotor and the outer diameter Dr of the rotor. Since 2.2 × Dr) / (2 × P), it is possible to further reduce the maximum value of the generated induced voltage waveform and torque pulsation.

  According to the invention of claim 4, since the space between the magnetic poles of adjacent iron cores is filled with the iron core, the maximum value of the generated induced voltage waveform can be further reduced.

  According to the invention of claim 5, since the number of stator slots is halved with respect to a predetermined number of stator slots per one phase, the maximum value of the generated induced voltage waveform and torque pulsation are further reduced. Can be reduced.

  According to the invention of claim 6, since the armature winding is constituted by concentrated winding, the permanent magnet type reluctance rotating electric machine can be miniaturized.

  Hereinafter, a permanent magnet type reluctance type rotating electrical machine according to an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the same or equivalent parts as those of the permanent magnet type reluctance rotating electric machine described in the background art section will be described using the same reference numerals as those used in the background art section.

  FIG. 1 is a circumferential sectional view of a permanent magnet type reluctance type rotating electrical machine according to a first embodiment of the present invention, FIG. 2 is an enlarged view of FIG. 1, and FIG. 3 is a rotor 2 of the first embodiment of the present invention. FIG. As shown in FIG. 1, the permanent magnet type reluctance type rotating electrical machine according to the first embodiment of the present invention includes a stator 1 and a rotor 2 that is rotatably arranged with a gap 9 (FIG. 2) inside the stator 1. It consists of and.

  The stator 1 has a stator core 3 and an armature winding 4. The stator core 3 is composed of a laminated structure of electromagnetic steel plates, and a stator slot 5 that houses an armature winding 4 and a stator tooth 6 that is a protruding portion that faces the rotor 2 on the inner peripheral side thereof. have.

  The rotor 2 includes a rotor core 7a and a rotor shaft 8 that is a rotation shaft. The rotor core 7a has a laminated structure of electromagnetic steel plates. A permanent magnet embedded hole 13 is formed in the rotor core 7a in a substantially V shape in the circumferential direction of the core. The permanent magnet embedded hole 13 is provided with a permanent magnet 12 magnetized in such a direction as to cancel the magnetic flux from the armature winding 4 passing between the magnetic poles 14 of the adjacent iron cores, and in the circumferential direction around the rotation axis. The easy magnetization direction (iron core magnetic pole 14) and the hard magnetization direction (between magnetic poles) are alternately formed. That is, in the magnetic pole 14 of the iron core, the permanent magnet 12 is magnetized in substantially the same direction, and between the magnetic poles, it is magnetized in a direction in which magnetic fluxes are added together. Thus, the rotor 2 having magnetic irregularities in the circumferential direction rotates around the rotor shaft 8 by the rotating magnetic field generated by the current flowing through the armature winding 4.

  Further, as shown in FIG. 3, the rotor 2 is divided into two in the direction of the rotation axis, and the divided rotor cores 7a are arranged so as to be shifted by an angle θ in the circumferential direction. An angle θ formed by the center of the magnetic pole 14 of one divided rotor core 7a and the center of the magnetic pole 14 of the other divided rotor core 7a with respect to the rotation axis is a skew angle θ of the rotor 2. By changing the skew angle θ, the maximum value of the induced voltage waveform and the torque pulsation change. FIG. 4 shows the relationship between the maximum value (pu) of the induced voltage waveform and the torque pulsation (pu) with respect to the rotor skew angle θ (degrees) of the permanent magnet type reluctance type rotating electrical machine of this embodiment. Note that the vertical axis of FIG. 4 is a converted value in which the value of torque pulsation when the skew angle is 13 degrees and 31 degrees is 1 (pu) (hereinafter, such converted value is expressed in the unit pu). As shown in FIG. 4, it can be seen that the maximum value of the induced voltage waveform is small when the skew angle θ is between 13 degrees and 32 degrees, and particularly shows a minimum value near 28 degrees. It can be seen that the torque pulsation is small when the skew angle θ is between 13 degrees and 31 degrees, and particularly shows a minimum value around 24 degrees.

  Therefore, the maximum value of the induced voltage waveform and the torque pulsation can be reduced by setting the skew angle θ to 13 degrees to 31 degrees. In this embodiment, as an example, the skew angle θ is set to 25 degrees in consideration of both the maximum value of the induced voltage waveform and the value of torque pulsation.

  Further, the rotor 2 has iron core magnetic poles 14 formed at equal intervals in the circumferential direction of the rotor iron core 7a, and the ratio between the interval between the magnetic poles 14 of the two adjacent iron cores and the width of the stator teeth is changed. Torque pulsation changes. That is, as shown in FIG. 2, the angle formed by the center line of the magnetic poles 14 of two adjacent iron cores with respect to the rotation axis (hereinafter referred to as the magnetic pole pitch angle) is β, and the width of the tip of the inner diameter surface of the stator tooth 6 is When the angle formed with respect to the rotation axis (hereinafter, stator teeth width angle) is γ, the torque pulsation is changed by changing the stator teeth width center angle coefficient γ / β, which is the ratio thereof. FIG. 5 shows the relationship of the torque pulsation (pu) to the stator tooth width center angle coefficient γ / β (pu) of the permanent magnet type reluctance type rotating electrical machine of the present embodiment. As shown in FIG. 5, the torque pulsation is such that the stator teeth width center angle coefficient γ / β decreases between 0.56 (pu) and 0.65 (pu), and the stator teeth width center angle coefficient γ It can be seen that the minimum value is exhibited when / β is 0.58 (pu).

  Therefore, the torque pulsation can be reduced by setting the stator teeth width angle γ to 0.56 × β to 0.65 × β, and the torque pulsation can be minimized by setting it to 0.58 × β. Can be a value. In this embodiment, as an example, the stator teeth width angle γ is set to 0.58 × β.

  Further, the maximum value of the induced voltage waveform and the torque pulsation change by changing the width w of the permanent magnet 12 with respect to the number of poles P of the rotor 2 and the outer diameter Dr of the rotor 2. FIG. 6 shows the relationship between the maximum value (pu) of the induced voltage waveform and the torque pulsation (pu) with respect to the permanent magnet width coefficient w × 2 × P / Dr (pu) of the permanent magnet type reluctance type rotating electrical machine of this example. Is. As shown in FIG. 6, the maximum value of the induced voltage waveform and the torque pulsation are such that the permanent magnet width coefficient w × 2 × P / Dr is small between 1.5 (pu) and 2.2 (pu). I understand.

  Therefore, by setting the permanent magnet width w to 1.5 × Dr / (2 × P) to 2.2 × Dr / (2 × P), an induced voltage waveform is obtained without impairing the torque characteristics and efficiency of the rotating electrical machine. The maximum value and torque pulsation can be reduced. In this embodiment, as an example, the permanent magnet width w is 1.8 × Dr / (2 × P).

  Further, the rotor core 7a of the permanent magnet type reluctance type rotating electrical machine of the present invention is formed with a triangular hole 100 formed in the rotor core 7 of the conventional permanent magnet type reluctance type rotating electrical machine shown in FIG. Instead, the space between the magnetic poles 14 of adjacent iron cores is filled with the iron core.

  The number of stator slots 5 of the present invention is fixed so that the number of stator slots per one phase is 36 when the number of poles P is 12, so that the number of stator slots per phase is 36. The child slot 5 was set to 18. The armature winding 4 is formed by concentrated winding.

  FIG. 7 shows an induced voltage waveform generated by the permanent magnet magnetic flux of the permanent magnet type reluctance type rotating electrical machine according to the first embodiment of the present invention configured as described above. The horizontal axis represents the electrical angle (degrees), and the vertical axis represents the induced voltage (pu). As shown in FIG. 7, the conventional induced voltage waveform includes harmonic order components, and the maximum value of the induced voltage waveform is a large value. Further, the induced voltage waveform of the conventional permanent magnet motor that approximates the induced voltage waveform to a sine wave has a large maximum value although the harmonic order component is suppressed. On the other hand, in the induced voltage waveform of the present embodiment, odd-order harmonic order components such as third order, fifth order, and seventh order are suppressed and the vicinity of the maximum value of the waveform is smoothed. That is, the induced voltage waveform of the present invention has an electrical angle of 0 to 50 degrees, 0 (pu) to 1 (pu), an electrical angle of 50 to 130 degrees, 1 (pu), and an electrical angle of 130 to 180 degrees. It can be seen that the trapezoidal shape changes from 1 (pu) to 0 (pu), and the maximum value of the induced voltage is greatly reduced.

  As described above, in the permanent magnet type reluctance type rotating electric machine according to the present embodiment, the skew angle θ of the magnetic pole 14 of the iron core is set to 25 degrees, so that the induced voltage waveform of the rotating electric machine is not impaired without damaging the torque characteristics and efficiency of the rotating electric machine. The harmonic component can be canceled out to obtain a trapezoidal induced voltage waveform, and the maximum value of the induced voltage generated in the rotating electrical machine can be greatly reduced. Furthermore, torque pulsation can be reduced, and the rotating electrical machine can be reduced in size, rotated at high speed, increased in torque, and reduced in vibration and noise.

  Further, since the stator teeth width angle γ is set to 0.58 × β with respect to the magnetic pole pitch angle β, the torque pulsation can be further reduced.

  Further, since the permanent magnet width w is 1.8 × Dr / (2 × P) with respect to the number P of the rotor and the outer diameter Dr of the rotor, the maximum value of the induced voltage waveform and the torque pulsation are further increased. Can be reduced.

  Further, the rotor core 7a is not formed with the triangular hole 100 formed in the rotor core 7 of the conventional permanent magnet type reluctance type rotating electric machine shown in FIG. Since it is filled with the iron core, the maximum value of the induced voltage waveform can be further reduced, and an induced voltage waveform closer to a trapezoid can be obtained.

  In addition, since the number of poles P is 12 and the number of stator slots 5 is 18 so that the number of stator slots 5 is ½ of the number of stator slots per pole per phase, the induced voltage The maximum value of the waveform and torque pulsation can be further reduced.

  Further, since the armature winding 4 is constituted by concentrated winding, it can be miniaturized and can be used as a flat type rotating electric machine.

  Therefore, by reducing the induced voltage, the rotating electric machine can be operated without destroying the energization circuit or the control circuit with the overvoltage, and the reliability is improved. In addition, since the withstand voltage of the energization circuit or control circuit that is set according to the value of the induced voltage can be set to a low value, the energization circuit or control circuit can be configured at low cost, greatly reducing costs. can do. Furthermore, torque pulsation can be greatly reduced, so that the torque generated by the rotating electrical machine can be utilized to the maximum, and the rotating electrical machine can be increased in torque, output, and efficiency, and also caused by torque pulsation. Electromagnetic vibration and noise are reduced and reliability and quietness can be significantly improved.

  In this embodiment, the rotor skew angle θ is 25 degrees, the stator teeth width angle γ is 0.58 × β, and the permanent magnet width w is 1.8 × Dr / (2 × P). The invention is not limited to this, the rotor skew angle θ is 13 degrees <θ <31 degrees, the stator teeth width angle γ is 0.56 × β <γ <0.65 × β, and the permanent magnet width. Even if w is set to a value within the range of 1.5 × Dr / (2 × P) <w <2.2 × Dr / (2 × P), the same effect can be obtained.

  Further, in the present embodiment, the rotor 2 is divided into two parts, but it may be divided into a plurality of parts and arranged at regular intervals in the circumferential direction.

  The present invention can be applied to various electric machines as a small-sized, high-output, high-efficiency rotating electrical machine.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circumferential sectional view of a permanent magnet type reluctance type rotating electrical machine according to a first embodiment of the present invention. It is an enlarged view of FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is an external appearance perspective view of the rotor of the permanent magnet type reluctance type rotary electric machine which concerns on Example 1 of this invention. It is the figure which showed the relationship between the rotor skew angle of the permanent magnet type reluctance type rotary electric machine which concerns on Example 1 of this invention, the maximum value of an induced voltage waveform, and torque pulsation. It is the figure which showed the relationship between the stator teeth width center angle coefficient of the permanent magnet type | mold reluctance type rotary electric machine which concerns on Example 1 of this invention, and torque pulsation. It is the figure which showed the relationship between the permanent magnet width coefficient of the permanent magnet type | mold reluctance type rotary electric machine which concerns on Example 1 of this invention, the maximum value of an induced voltage waveform, and torque pulsation. It is the figure which showed the induced voltage waveform of the permanent-magnet-type reluctance type rotary electric machine which concerns on Example 1 of this invention. It is a circumferential direction sectional view of the conventional permanent magnet type reluctance type rotating electrical machine. It is the circumferential direction sectional view showing one pole pair of the conventional interior permanent magnet motor. It is the figure which showed the induced voltage waveform of the conventional embedded permanent magnet motor.

Explanation of symbols

1, 101 Stator 2, 102 Rotor 3 Stator core 4, 104 Armature winding 5 Stator slot 6 Stator teeth 7 Rotor core 8 Rotor shaft 9, 109 Gap 12, 112 Permanent magnet 13 Permanent magnet embedded Hole 14 Iron core magnetic pole 100 Triangular hole

Claims (6)

A stator having armature windings;
A rotor rotatably provided inside the stator and having a rotor core;
A permanent magnet disposed in the rotor core so as to cancel the magnetic flux from the armature winding passing between the magnetic poles of adjacent iron cores of the rotor;
A permanent magnet type reluctance type rotating electrical machine with
The rotor is divided into two in the direction of the rotation axis, and the divided rotors are arranged so as to be shifted in the circumferential direction. The magnetic pole center of one of the divided rotor cores and the magnetic pole center of the other divided rotor core And the angle formed with respect to the rotation axis is the skew angle θ,
The skew angle θ is
A permanent magnet type reluctance type rotating electrical machine characterized in that 13 degrees <θ <31 degrees. The stator has a stator tooth that is a convex portion protruding from the inner surface, and the inner diameter surface of the stator tooth with respect to an angle β formed by the center line of the magnetic poles of two adjacent iron cores with respect to the rotation axis The angle γ formed by the width of the tip with respect to the rotation axis is
0.56 × β <γ <0.65 × β
The permanent magnet type reluctance type rotating electrical machine according to claim 1, wherein: The width w of the permanent magnet is such that the number of poles P of the rotor and the outer diameter Dr of the rotor are
(1.5 × Dr) / (2 × P) <w <(2.2 × Dr) / (2 × P)
The permanent magnet type reluctance type rotating electrical machine according to claim 1 or 2, wherein   The permanent magnet type reluctance type rotating electrical machine according to any one of claims 1 to 3, wherein a space between magnetic poles of adjacent iron cores is filled with an iron core.   The stator has a stator slot for accommodating the armature winding, and the number of stator slots is ½ of a predetermined number of stator slots per one phase and one pole. The permanent magnet type reluctance type rotating electrical machine according to any one of claims 1 to 4. The permanent magnet type reluctance rotating electric machine according to any one of claims 1 to 5, wherein the armature winding is constituted by concentrated winding.

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