JP4198545B2 - Permanent magnet type rotating electric machine and electric compressor using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a permanent magnet type rotating electric machine having a permanent magnet for a field in a rotor, and more particularly to a permanent magnet type rotating electric machine mounted on an air conditioner, a compressor of a refrigerator and a freezer.
[0002]
[Prior art]
Conventionally, in this type of permanent magnet type rotating electrical machine, various measures have been taken to reduce the armature reaction magnetic flux. For example, the outer periphery of the rotor core is made non-concentric with a convex shape with respect to the shaft, and a plurality of elongated holes (substantially rectangular slits) are provided in the rotor core above the permanent magnet so that the magnetic flux in the gap portion The density distribution is smoothed to reduce the harmonic magnetic flux (armature reaction magnetic flux).
[0003]
That is, in the permanent magnet type rotating electrical machine, a plurality of slits extending from the inner peripheral side of the rotor to the outer peripheral side are formed in the rotor core on the outer peripheral side of the permanent magnet, and the distance between adjacent slits is It has been proposed to arrange the outer peripheral side to be narrower than the inner peripheral side, and to arrange the slit symmetrically with respect to the magnetic pole center of the rotor core (for example, see Patent Document 1).
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-252840
[Problems to be solved by the invention]
In the above prior art, since the magnetic pole has a convex shape, the equivalent gap is increased, the armature current is increased to obtain a required output, and the harmonic magnetic flux is increased. In addition, a plurality of slits are formed to reduce the armature reaction magnetic flux, but if the slits are provided, the induced electromotive force waveform is also affected. In other words, the slits provided in the magnetic pole part of the rotor core have an optimum shape and arrangement.
[0006]
Furthermore, in order to reduce the noise of the permanent magnet type rotating electric machine, it is important to reduce the generated harmonic magnetic flux by bringing the current flowing through the armature winding close to a sine wave especially in the case of concentrated winding. Therefore, it is better to drive with a 180-degree energizing inverter, but the current flowing through the armature winding is the voltage applied to the permanent magnet type rotating electrical machine (output voltage of the inverter) and the induced electromotive force of the permanent magnet type rotating electrical machine. Since it flows by the differential voltage, even if the output voltage of the inverter is a sine wave, if the induced electromotive force waveform is not a sine wave, the armature current includes a harmonic component, and a harmonic magnetic flux is generated. Therefore, in order to reduce the harmonic magnetic flux, the induced electromotive force waveform may be approximated to a sine wave.
[0007]
In Patent Document 1, it is described that a slit is disposed. However, in order to reduce harmonics more efficiently without deteriorating the effective magnetic flux (fundamental wave magnetic flux) of the permanent magnet, which slit shape is selected. It is not considered whether to do so.
[0008]
An object of the present invention is a permanent magnet type rotating electrical machine that can solve the noise problem by reducing the harmonic magnetic flux sufficiently by bringing the induced electromotive force waveform close to a sine wave without impairing the effective magnetic flux (fundamental wave magnetic flux) of the permanent magnet. Is to provide.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is formed on a rotor core and a stator in which concentrated armature windings are provided so as to surround teeth in a plurality of slots formed on the stator core. In a permanent magnet type rotating electrical machine in which a rotor in which a permanent magnet is housed in a plurality of permanent magnet insertion holes is rotatably supported via a gap on the inner periphery of the stator, the rotor on the outer peripheral side of the permanent magnet A plurality of slits extending from the inner peripheral side of the rotor to the outer peripheral side are formed in the iron core, and the circumferential width of the plurality of slits provided in the rotor core gradually decreases from the inner peripheral side to the outer peripheral side of the rotor. The present invention proposes a permanent magnet type rotating electrical machine that is configured as described above.
[0010]
As described above, in the present invention, a plurality of slits are formed in the magnetic pole portion of the rotor core for concentrating the magnetic flux of the permanent magnet flowing into the stator on the d-axis side so as not to impair the effective magnetic flux (fundamental wave magnetic flux). The circumferential widths of the plurality of slits are gradually narrowed from the inner peripheral side to the outer peripheral side of the rotor core. Therefore, the magnetic flux interlinking with the armature winding approaches a sine wave, and the induced electromotive force also approaches the sine wave. Therefore, the harmonic magnetic flux is reduced, and a permanent magnet type rotating electrical machine with less noise problems can be provided.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. In each figure, the common code | symbol shows the same thing. Further, here, a 4-pole permanent magnet type rotating electric machine is shown, and the ratio of the number of poles of the rotor to the number of slots is set to 2: 3.
[0012]
(Embodiment 1)
FIG. 1 shows a radial cross-sectional shape of the first embodiment of the permanent magnet type rotating electrical machine according to the present invention, and FIG. 2 shows an enlarged view of the radial cross-sectional shape of the rotor of the first embodiment according to the present invention.
[0013]
In FIG. 1 and FIG. 2, the permanent magnet type rotating electrical machine 1 includes a stator 2 and a rotor 3.
[0014]
The stator 2 includes a stator core 6 including a tooth 4 and a core back 5, and concentrated winding armature windings 8 (three-phase windings) wound around the teeth 4 in slots 7 between the teeth 4. U-phase winding 8A, V-phase winding 8B, and W-phase winding 8C). Here, since the permanent magnet type rotating electrical machine 1 has 4 poles and 6 slots, the slot pitch is 120 degrees in electrical angle.
[0015]
The rotor 3 includes a shaft hole 15 in which a permanent magnet 14 is housed in a single-letter permanent magnet insertion hole 13 formed in the rotor core 12 and is fitted to a shaft (not shown). Here, assuming that the axis extending in the magnetic pole center direction of the rotor 3 is the d axis and the axis extending in the direction between the magnetic poles 90 degrees apart from the magnetic pole center direction by the electrical angle is the q axis, the pole is formed on the outer circumferential surface of the rotor core 12. By providing the concave portion 11 having a shape obtained by combining two substantially V-shapes cut in a straight line on the q-axis side therebetween, a magnetic pole core that serves to collect the magnetic flux of the permanent magnet 14 is formed. Here, the magnetic pole angle θ7, which is a concentric arc with the inner peripheral surface of the stator 2, is substantially equal to the slot pitch.
[0016]
Further, since the magnetic flux of the permanent magnet 14 that is gathered at the magnetic pole part of the rotor core 12 by the concave portion 11 is gathered further to the d-axis side, the slit 10 that moves from the inner peripheral side to the outer peripheral side at the magnetic pole part of the rotor core 12. Is provided. The slits 10 (consisting of 10a and 10b) are arranged symmetrically with respect to the d-axis and are provided to collect magnetic flux on the d-axis side so as not to impair the effective magnetic flux (fundamental wave magnetic flux). The outer circumferential side is made narrower than the inner circumferential side of the rotor core 12.
[0017]
Here, the circumferential width of the plurality of slits 10 a and 10 b provided in the rotor core 12 is L1, the circumferential width from the inner circumferential side of the rotor core 12 is L1, and the circumferential width from the outer circumferential side of the rotor core 12 L2, the circumferential length of the permanent magnet 14 is L3, and the length between the recesses 11 provided between the outer peripheral surfaces of the rotor core 12 is L4.
L1 / L2 = L3 / L4 (1)
They are arranged so that
[0018]
Further, the distance between the slit 10a and the slit 10b is narrower on the outer peripheral side (stator 2 side: θ1) than on the inner peripheral side (permanent magnet 14 side: θ2). Here, although the magnetic flux flowing into the stator 2 from between the slit 10a and the slit 10b can be made very large, the magnetic flux of the permanent magnet 14 flows into the stator 2 from the teeth 4, so the saturation at the teeth 4 portion is alleviated. Thus, it is better to effectively use the magnetic flux of the permanent magnet 14. Therefore, since the end of the tooth tip 25 is likely to be saturated, the distance (θ1) on the outer peripheral side (stator 2 side) between the slit 10a and the slit 10b is set to be equal to or less than the width of the tooth 4 (θ3 or less).
[0019]
Furthermore, in order to secure the magnetic flux flowing into the stator 2 side from the portion between the slit 10 and the end of the magnetic core (increasing the magnetic flux stepwise from the q-axis side toward the d-axis side), the slit 10a and the slit The distance (θ2) on the inner peripheral side (permanent magnet 14 side) between 10b is made smaller than the width (θ9) of the permanent magnet 14.
[0020]
By the way, in the permanent magnet type rotating electrical machine 1 for driving the compressor which is the subject of the present invention, noise often becomes a problem. Although the pulsation torque is a factor that increases the noise of the permanent magnet type rotating electrical machine 1, the pulsation torque can be simply increased by increasing the gap length and decreasing the magnetic flux density of the gap. However, if the gap length is widened and the magnetic flux density of the gap is reduced, the output is reduced by that amount, so that it is necessary to increase the physique to maintain the same output as a result. Therefore, in order to reduce the pulsation torque without reducing the magnetic flux of the permanent magnet 14 that contributes to the magnet torque, the harmonic component of the armature magnetic flux may be reduced.
[0021]
Therefore, it is preferable to drive with a 180-degree energizing inverter, but the current flowing through the armature winding 8 is the voltage applied to the permanent magnet type rotating electrical machine 1 (the output voltage of the inverter) and the induction of the permanent magnet type rotating electrical machine 1. Since the current flows due to the difference voltage of the power, even if the output voltage of the inverter is a sine wave, if the induced electromotive force waveform is not a sine wave, the armature current includes a harmonic component and a harmonic magnetic flux is generated. Therefore, in order to reduce the pulsation torque, the induced electromotive force waveform may be approximated to a sine wave.
[0022]
FIG. 3 shows the induced electromotive force waveform (a) and the harmonic analysis result (b) of Embodiment 1 according to the present invention. As shown in FIG. 3, the induced electromotive force waveform in the present invention is very close to a sine wave (5th order component: about 6.1%, 7th order component: about 1.9%), and the waveform distortion rate is About 7.2%.
[0023]
As described above, in the present invention, the permanent magnet 14 on the d-axis side is not damaged by the effective shape (fundamental wave flux) without damaging the effective magnetic flux (fundamental wave flux) by the outer peripheral shape of the rotor core 12 and the shape and arrangement of the slit 10 provided in the magnetic pole part of the rotor core 12. Therefore, the induced electromotive force waveform approaches a sine wave, the pulsating torque during operation is reduced, and noise can be reduced.
[0024]
Here, the magnetic pole angle θ7 (concentric arc) is substantially equal to the slot pitch (120 degrees), but the optimum value of θ7 varies depending on the shape and width of the teeth 4 and the optimum value is within the range of 90 to 120 degrees. is there.
[0025]
(Embodiment 2)
FIG. 4 is a cross-sectional view showing the rotor core shape of the second embodiment of the permanent magnet type rotating electrical machine according to the present invention.
[0026]
4 is different from FIG. 2 in that a slit 10c and a slit 10d are provided in addition to the slit 10a and the slit 10b in the magnetic pole portion of the rotor core 12. In FIG. The slits 10c and 10d are arranged symmetrically with respect to the d-axis, and in order to collect magnetic flux on the d-axis side while suppressing a decrease in effective magnetic flux (fundamental wave magnetic flux) due to magnetic saturation on the outer peripheral side of the rotor core 12. Since it is provided, the circumferential width of the slit 10 is narrower on the outer peripheral side than the inner peripheral side of the rotor core 12. Here, the circumferential width of the plurality of slits 10c provided in the rotor core 12 is L5, the circumferential width from the inner peripheral side of the rotor core 12 is L5, and the circumferential width from the outer peripheral side of the rotor core 12 is L6. When the length in the circumferential direction of the permanent magnet 14 is L3 and the length between the recesses 11 provided between the poles of the outer peripheral surface of the rotor core 12 is L4,
L5 / L6 = L3 / L4 (2)
They are arranged so that If comprised in this way, the magnetic flux of a permanent magnet will be reduced only a harmonic component further, and a fundamental wave magnetic flux will not be impaired.
[0027]
Further, the distance (θ5) on the outer peripheral side (stator 2 side) is made narrower than the distance (θ6) on the inner peripheral side (permanent magnet 14 side). In order to further secure the magnetic flux flowing into the stator 2 side from the portion between the slit 10 and the end of the magnetic core (increasing the magnetic flux stepwise as it approaches the d-axis side from the q-axis side), the slit 10c and the slit The distance (θ6) on the inner circumference side (permanent magnet 14 side) between 10d is set to be equal to or less than the width of the tooth 4 (θ3 or less).
[0028]
FIG. 5 shows an induced electromotive force waveform (a) and a harmonic analysis result (b) thereof according to the second embodiment of the present invention. As shown in FIG. 5, the induced electromotive force waveform is close to a sine wave (5th order component: about 4.3%, 7th order component: about 1.0%), and the waveform distortion rate is about 4.9%. It can be seen that the harmonic components are further reduced as compared with the first embodiment shown in FIG.
[0029]
Therefore, the second embodiment according to the present invention is based on the outer peripheral shape of the rotor core 12 and the shape and arrangement of the slit 10 provided in the magnetic pole part of the rotor core 12 so that the effective magnetic flux (fundamental wave flux) is not impaired. In addition, since the magnetic flux of the permanent magnet 14 can be collected, the induced electromotive force waveform also approaches a sine wave, so that it is needless to say that the same effects as those of the first embodiment shown in FIG. 2 can be obtained.
[0030]
(Embodiment 3)
FIG. 6 is a cross-sectional view showing the rotor core shape of the third embodiment of the permanent magnet type rotating electrical machine according to the present invention.
[0031]
6 differs from FIG. 2 in that the arrangement of the slits 10a and 10b is the same, but the permanent magnet insertion hole 13 formed in the rotor core 12 has a V-shape that is convex with respect to the axis of the rotor 3. In other words, a substantially V-shaped recess 16 that is linearly cut is formed on the side (q-axis) between the outer peripheral surfaces of the rotor core 12. Here, as shown in FIG. 2, the concave portion 16 is different in shape from the concave portion 11 formed by combining two substantially V-shapes, but is arranged in a convex V shape with respect to the axis of the rotor 3. Since the magnet angle θ9 of the permanent magnet 14 is substantially equal to the slot pitch (120 degrees), a magnetic pole core that serves to collect the magnetic flux of the permanent magnet 14 is formed in the same manner as the concave portion 11.
[0032]
Therefore, the effective magnetic flux (fundamental wave flux) is not impaired by the outer peripheral shape of the rotor core 12 and the shape and arrangement of the slit 10 provided in the magnetic pole part of the rotor core 12 in the third embodiment according to the present invention. Since the magnetic fluxes of the permanent magnets 14 are gathered, it goes without saying that the same effects as those of the first embodiment shown in FIG. 2 can be obtained.
[0033]
(Embodiment 4)
FIG. 7 is a cross-sectional view of Embodiment 4 of the permanent magnet type rotating electrical machine according to the present invention.
[0034]
In FIG. 7, the structure of the rotor 3 is the same as that of FIG. 1, but the structure of the stator 2 is different. 1 differs from FIG. 1 in that the center of the stator tooth tip 25 is concentric with the rotor core 12 and both ends of the tooth tip 25 are linear, that is, away from the rotor 3.
[0035]
In such a configuration, the stator 2 also has a structure in which the induced electromotive force waveform approximates a sine wave. Therefore, the induced electromotive force waveform further approaches the sine wave, and the harmonic component of the armature current is smaller than in the case of FIG. As a result, the harmonic magnetic flux decreases. Therefore, since the pulsation torque is also reduced, noise can be significantly reduced.
[0036]
(Embodiment 5)
FIG. 8 shows a cross-sectional structure of a compressor according to the present invention.
[0037]
The compressor is formed by meshing a spiral wrap 62 standing upright on the end plate 61 of the fixed scroll member 60 and a spiral wrap 65 standing upright on the end plate 64 of the orbiting scroll member 63. A compression operation is performed by rotating the shaft 72. Of the compression chambers 66 (66a, 66b,...) Formed by the fixed scroll member 60 and the orbiting scroll member 63, the compression chamber located on the outermost side is the scroll members 60 and 63 with the orbiting motion. The volume gradually decreases. When the compression chambers 66 a and 66 b reach the vicinity of the centers of the scroll members 60 and 63, the compressed gas in both the compression chambers 66 is discharged from a discharge port 67 communicating with the compression chamber 66. The discharged compressed gas passes through gas passages (not shown) provided in the fixed scroll member 60 and the frame 68 and reaches the compression container 69 below the frame 68, and a discharge pipe provided on the side wall of the compression container 69. 70 is discharged out of the compressor.
[0038]
Further, in the present compressor, the driving motor 1 is enclosed in the pressure vessel 69 and rotates at a rotational speed controlled by a separate inverter (not shown) to perform a compression operation. Here, the drive motor 1 is a permanent magnet type rotating electrical machine 1 including a stator 2 and a rotor 3. In FIG. 8, 8 is an armature winding, 12 is a rotor core, 73 is an oil reservoir, 74 is an oil hole, and 75 is a sliding bearing.
[0039]
As described above, when the permanent magnet type rotating electrical machine 1 is used as the drive motor 1 such as a compressor, the operation is controlled by the control device (inverter). As described above, the waveform of the armature current is determined by the voltage difference between the voltage (output voltage of the control device) applied to the permanent magnet type rotating electrical machine 1 and the induced electromotive force waveform of the permanent magnet type rotating electrical machine 1. The harmonic component of the armature current is reduced by bringing the induced electromotive force waveform close to a sine wave. However, if the permanent magnet type rotating electrical machine 1 is operated by a control device in which the waveform of the output voltage is a sine wave, the armature is further increased. The harmonic component of the current can be reduced. Therefore, if the permanent magnet type rotating electrical machine 1 shown in the present invention and the control device in which the waveform of the output voltage is a sine wave are combined, noise can be significantly reduced.
[0040]
【The invention's effect】
According to the present invention, the induced electromotive force waveform can be made a sine wave without impairing the effective magnetic flux (fundamental wave magnetic flux) of the permanent magnet. Therefore, it is possible to provide a permanent magnet type rotating electrical machine that can sufficiently reduce the harmonic magnetic flux and solve the noise problem.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a first embodiment of a permanent magnet type rotating electrical machine according to the present invention.
2 is a cross-sectional view showing the rotor core shape of FIG. 1. FIG.
FIG. 3 is a diagram showing the induced electromotive force waveform of FIG. 1 and its harmonic analysis results;
FIG. 4 is a cross-sectional view showing a rotor core shape of a second embodiment of a permanent magnet type rotating electrical machine according to the present invention.
5 is a diagram showing the induced electromotive force waveform of FIG. 4 and its harmonic analysis results;
FIG. 6 is a cross-sectional view showing a rotor core shape of a third embodiment of the permanent magnet type rotating electric machine according to the present invention.
FIG. 7 is a cross-sectional view of a fourth embodiment of a permanent magnet type rotating electric machine according to the present invention.
FIG. 8 is a diagram showing a cross-sectional structure of a compressor according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Permanent magnet type rotary electric machine (drive motor), 2 ... Stator, 3 ... Rotor, 4 ... Teeth, 5 ... Core back, 6 ... Stator iron core, 7 ... Slot, 8 ... Armature winding, 10 DESCRIPTION OF SYMBOLS ... Slit, 11 ... Recessed part, 12 ... Rotor core, 13 ... Permanent magnet insertion hole, 14 ... Permanent magnet, 15 ... Shaft hole, 16 ... Recessed part, 17 ... Long hole part (slit), 25 ... Tip part of teeth, 60 ... fixed scroll member, 61 ... end plate, 62 ... wrap, 63 ... orbiting scroll member, 64 ... end plate, 65 ... wrap, 66 ... compression chamber, 67 ... discharge port, 68 ... frame, 69 ... compression container, 70 ... Discharge pipe, 72 ... shaft, 73 ... oil sump, 74 ... oil hole, 75 ... slide bearing.

Claims (8)

A permanent magnet is inserted into a stator in which concentrated armature windings are provided so as to surround teeth in a plurality of slots formed in the stator core, and a plurality of permanent magnet insertion holes formed in the rotor core. In the permanent magnet type rotating electrical machine in which the housed rotor is rotatably supported through the gap on the inner periphery of the stator,
A plurality of slits extending from the inner peripheral side of the rotor to the outer peripheral side are formed in the rotor core on the outer peripheral side of the permanent magnet, and the circumferential width of the plurality of slits provided in the rotor core is set to the rotation The outer peripheral side is made narrower than the inner peripheral side of the core, and the distance between adjacent slits is arranged so that the outer peripheral side is narrower than the inner peripheral side of the rotor core, and is provided in the rotor core. The circumferential width of the plurality of slits is L1, the circumferential width that is the widest from the inner peripheral side of the rotor core, and the circumferential width that is the narrowest from the outer peripheral side of the rotor core, L2. When the circumferential length of the magnet is L3 and the distance between the concave portions provided between the poles of the outer peripheral surface of the rotor core is L4,
L1 / L2 = L3 / L4
A permanent magnet type rotating electrical machine characterized in that it is configured as follows. In the permanent magnet type rotating electrical machine according to claim 1,
A permanent magnet type rotating electrical machine, wherein a plurality of slits provided in the rotor core are arranged symmetrically with respect to a magnetic pole center of the rotor core . In the permanent magnet type rotating electrical machine according to claim 1 or 2,
A permanent magnet type rotating electrical machine , wherein concave portions are formed between the poles of the outer peripheral surface of the rotor core such that the magnetic pole angle of the rotor core is in an electrical angle range of 90 degrees to 120 degrees . In the permanent magnet type rotating electrical machine according to any one of claims 1 to 3,
When the permanent magnet's magnetic flux axis is d-axis and the axis orthogonal to the d-axis is q-axis, the distance between the slits provided closest to the q-axis is on the outer peripheral side of the rotor core, A permanent magnet type rotating electrical machine formed so as to be equal to or less than a teeth width of the stator core . The permanent magnet type rotating electrical machine according to any one of claims 1 to 4,
When the magnetic axis of the permanent magnet is the d-axis and the axis orthogonal to the d-axis is the q-axis, the distance between the slits provided closest to the q-axis is the inner peripheral side of the rotor core. The permanent magnet type rotating electrical machine is arranged so as to be narrower than the width of the permanent magnet. The permanent magnet type rotating electrical machine according to any one of claims 1 to 5,
The permanent magnet embedded in the rotor core has a single letter shape with respect to the axis of the rotor or a V shape that is convex with respect to the axis of the rotor. Magnet rotating electric machine. The permanent magnet type rotating electrical machine according to any one of claims 1 to 6,
A permanent magnet type wherein two or more types of gap surfaces having different gap lengths are formed on the inner peripheral surface of the teeth of the stator core so that the gap length of the end portion is larger than the central portion of the tip end of the teeth. Rotating electric machine. The compressor which used the permanent magnet type rotary electric machine of any one of Claim 1 thru | or 7 as a drive source .

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