JP2007166798A - Dynamo-electric machine, compressor, blower, and air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve efficiency by induced voltage, in a double armature motor excellent in downsizing and high efficiency. <P>SOLUTION: This motor is the so-called double armature motor which is equipped with a rotor 100, an inner stator 200 where an armature coil 201 is wound, and an outer stator 300 where an armature coil 301 is wound. The ratio of the number Pn of pole pairs of an inner stator 200 to the number Pg of pole pairs of an outer stator 300 is selected to be equal to the ratio of magnitude of the field magnetic flux interlinked to the armature coil 301 to the magnitude Φn of the field magnetic flux interlinked to the armature coil 201. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a structure of a rotating electrical machine and a control method thereof.

  In order to reduce the size of a rotating electrical machine, for example, an electric motor and increase efficiency, it is desirable to generate a field magnetic flux with a permanent magnet. Taking an electric motor as an example, a permanent magnet excitation motor is desirable from the viewpoint of miniaturization and high efficiency.

  The generated torque of the permanent magnet excitation motor is proportional to the number of turns of the armature winding, the current flowing through the armature winding, and the field magnetic flux linked to the armature winding. The larger the electric motor, the larger the surface area of the permanent magnet, and the larger the sectional area of the armature winding itself (hereinafter referred to as “line sectional area”). The field magnetic flux can be increased as the surface area of the permanent magnet increases. The larger the wire cross-sectional area, the lower the electrical resistance of the armature winding and the lower the copper loss. Therefore, an increase in generated torque (or efficiency when the same torque is generated) and a reduction in size of the motor are in a trade-off relationship.

  As a structure excellent in miniaturization and high efficiency, a so-called double amateur motor is known. This is an electric motor in which one field element is provided with a pair of armatures facing each other from opposite sides. Patent Documents 1 and 2 below disclose a cylindrical double amateur motor. Patent Document 2 discloses a technique in which permanent magnets are separately provided on the inner and outer peripheral sides as field elements, and the current phase is controlled by the respective inverters, which is reduced in size and generated while reducing torque ripple. It is intended to improve torque.

  The torque generated in a double amateur motor is the torque that acts between the outer armature and the field element (hereinafter referred to as “outer torque”) and the torque that acts between the inner armature and the field element. (Hereinafter referred to as “inner peripheral side torque”). Whether it is the outer peripheral torque or the inner peripheral torque, the number of turns of the armature winding of the corresponding armature, the current flowing therethrough, and the linkage to this are the same as the torque generated in a normal motor. It is proportional to the product of field magnetic flux.

  Non-patent document 1 below introduces general indices of permanent magnet excitation synchronous motors. If the motors have the same cooling conditions and the same dimensions, the allowable loss Wc can be considered to be substantially the same from the relationship between the temperature rise and the heat dissipation. The torque T and the allowable loss Wc are in the relationship of the expression (1), and the coefficient Km is called a motor constant.

  T = Wc · √Km (1)

  That is, when the allowable loss Wc is constant, the torque T increases as the motor constant Km increases. Therefore, the motor constant Km can be used as an index value of the allowable torque (usually continuous rated torque).

  The motor constant Km can be expressed by equation (2). Here, the number p of pole pairs, the maximum winding flux linkage Φ, the space factor fs, the total cross sectional area St of the winding slot, the specific resistance ρ of the winding, and the average length l of the unit coil were introduced. The current waveform was a sine wave, and it was assumed that the magnetic flux alternated in a sine wave shape. In addition, the loss of the electric motor is considered by omitting the iron loss because the copper loss is most, especially when the electric motor is small.

  Km = (1/2) pΦ√ (fsSt / ρl) (2)

  Therefore, in order to increase the motor efficiency per volume of the motor, it is necessary to increase the motor constant Km, and the following policies are effective from the equation (2).

(i) Increase winding space factor fs
(ii) Shorten the average length l of the unit coil
(iii) Reduce the specific resistance ρ of the winding
(iv) Increase the maximum winding flux linkage Φ
(v) Increase the number of pole pairs p
(vi) Increase the total cross-sectional area St of the winding slot.

  Therefore, since the double armature motor is provided with two armatures, it is advantageous from the viewpoint of the policy (vi).

JP 2002-335658 A JP 2002-369467 A Kazuo Onishi, “Torque Evaluation of Permanent Magnet Motor and Examination of Optimal Structure”, IEEJ Transactions D, Industrial Application Division, 1995, Vol. 115, No. 7, pp. 930-935 Research Committee on Performance Improvement of Special-Use-Oriented Reluctance Torque Applied Motor, “Improvement of Performance of Special-Use-Oriented Reluctance Torque Applied Motor”, IEEJ Technical Report No. 920, March 2003

  However, the double amateur motor has a problem that the magnetic resistance increases and the operating point of the permanent magnet decreases. This is because the two armatures face each other from the opposite side to the field element, so there are two gaps between the field element and the armature, commonly referred to as the air gap, and they are the field magnetic flux. This is because they are connected in series as a magnetic resistance against the.

  The above-described decrease in operating point in a double amateur motor leads to a decrease in field magnetic flux interlinking with the armature as compared with a motor provided with only one armature. In other words, it is disadvantageous from the viewpoint of the above policy (iv).

  In the technique disclosed in Patent Document 2, since the permanent magnets are provided in the inner and outer two layers, there is a possibility that the problem of the decrease in the operating point can be compensated. However, there are also factors that hinder downsizing, such as an increase in the amount of permanent magnets used and an increase in the thickness of the field element.

  The present invention has been made in view of the above problems, and an object of the present invention is to further improve the performance of a double amateur rotating electrical machine excellent in miniaturization and high efficiency.

  As an example of the purpose, there is an improvement in efficiency due to an induced voltage of the electric motor.

  A first aspect of the rotating electrical machine according to the present invention is a rotor having a field magnet (102) that has a cylindrical shape including an outer peripheral surface (101a) and an inner peripheral surface (101b) and supplies a field magnetic flux. (100), facing the rotor from the inner peripheral surface side, facing the inner stator (200) around which the armature winding (201) is wound, and facing the rotor from the outer peripheral surface side And an outer stator (300) around which the armature winding (301) is wound. The ratio of the number of pole pairs (Pn) of the inner circumference side stator to the number of pole pairs (Pg) of the outer circumference side stator and the field magnetic flux interlinking with the armature winding of the outer circumference side stator. And the ratio of the field magnetic flux magnitude (Φn) linked to the armature winding of the inner peripheral side stator are selected to be equal.

  A second aspect of the rotating electrical machine according to the present invention is the first aspect, wherein the number of pole pairs (Pn) of the inner peripheral side stator (200) and the number of pole pairs of the outer peripheral side stator (300) ( Pg) is equal to the magnitude (Φ0n) of the field magnetic flux linked per turn of the armature winding of the inner peripheral side stator and per turn of the armature winding of the outer side stator. The field magnetic flux magnitude (Φ0g) interlinked with the outer peripheral stator, the number of turns (Tg) of the armature winding of the outer stator, and the armature winding of the inner stator. The ratio with the winding number (Tn) is selected to be equal.

  The compressor according to the present invention employs the rotating electric machine as an electric motor, and compresses the refrigerant by the electric motor.

  The blower according to the present invention employs the rotating electric machine as an electric motor and blows air using the electric motor.

  The air conditioner according to the present invention includes at least one of the compressor and the blower.

  The rotor moves at the same mechanical angular velocity with respect to both the outer peripheral side stator and the inner peripheral side stator. Therefore, the field flux interlinked with the armature winding of the inner side stator changes in proportion to the number of pole pairs of the inner side stator, and the field flux interlinked with the armature winding of the outer side stator. Changes in proportion to the number of pole pairs of the outer stator. According to the first aspect of the rotating electrical machine according to the present invention, the magnitude of the field magnetic flux interlinking with the armature winding and the changing speed thereof are equal between the inner peripheral side stator and the outer peripheral side stator. In any stator, the induced voltage at no load can be made equal.

  According to the second aspect of the rotating electrical machine according to the present invention, in the two stators having the same number of pole pairs, the magnitudes of the field magnetic fluxes linked to the respective armature windings are set equal. The induced voltage at no load in each stator can be made equal.

  The rotating electrical machine according to the present invention can be employed as an electric motor, and can be applied to a compressor and a blower. The compressor and blower can be applied to an air conditioner.

First embodiment.
FIG. 1 is a cross-sectional view illustrating the structure of a double amateur electric motor according to a first embodiment of the present invention, and shows a cross section perpendicular to a rotation axis Q. The electric motor includes a rotor 100, an inner peripheral side stator 200, and an outer peripheral side stator 300. The rotor 100 rotates about the rotation axis Q with respect to the inner peripheral side stator 200 and the outer peripheral side stator 300.

  The rotor 100 is a field element, and has a field magnet 102 and a magnetic body 103 that generate a field magnetic flux. The rotor 100 has a cylindrical shape including an outer peripheral surface 101a and an inner peripheral surface 101b. Since the extending direction of the cylindrical shape is parallel to the rotation axis Q, both the outer peripheral surface 101a and the inner peripheral surface 101b appear as circles in FIG.

  The field magnet 102 switches its polarity alternately in the circumferential direction with respect to the outer circumferential surface 101a and directs its magnetic pole surface. The same applies to the inner peripheral surface 101b.

  The inner peripheral side stator 200 is an armature that faces the rotor 100 from the inner peripheral surface 101b side. The outer peripheral side stator 300 is an armature that faces the rotor 100 from the outer peripheral surface 101a side. Armature windings 201 and 301 are wound around the inner periphery side stator 200 and the outer periphery side stator 300, respectively.

  More specifically, the inner peripheral side stator 200 has a tooth portion 202, and an armature winding 201 is wound around the tooth portion 202. The tip of the tooth portion 202 on the rotor 100 side extends in the circumferential direction. Similarly, the outer peripheral side stator 300 has a tooth portion 302, and an armature winding 301 is wound around the tooth portion 302. The tip of the tooth portion 302 on the rotor 100 side extends in the circumferential direction.

  Thus, in the double amateur motor, the motor constant Km can be increased by increasing the total cross-sectional area of the winding slot, which is the region where the armature winding is disposed.

  Here, as the structure of the rotor 100, a so-called permanent magnet embedded type in which a field magnet 102 is embedded in a magnetic body 103 is illustrated. Therefore, a structure in which the outer peripheral surface 101 a and the inner peripheral surface 101 b are defined by the magnetic body 103 is illustrated. However, if the field magnetic flux generated from the field magnet 102 is linked to the inner peripheral side stator 200 and the outer peripheral side stator 300, the field magnet 102 is either one of the outer peripheral surface 101a and the inner peripheral surface 101b. It may be a permanent magnet surface type that defines Alternatively, the field magnet 102 may be configured as a ring magnet that is magnetized so that a magnetic pole appears in the radial direction and the polarity of the magnetic pole is alternately switched in the circumferential direction without providing the magnetic body 103.

  Further, in FIG. 1, a four-pole six-slot motor is illustrated, but other pole numbers and slot numbers can be applied.

  When the motor is unloaded and the rotor 100 rotates at the electrical angular velocities ωen and ωeg with respect to the inner peripheral side stator 200 and the outer peripheral side stator 300, they are induced in the armature windings 201 and 301, respectively. The voltages (no-load induced voltages) Vn and Vg are expressed as follows by introducing the field magnetic flux magnitudes Φn and Φg linked to the armature windings 201 and 301, respectively.

  Vn = ωen · Φn, Vg = ωeg · Φg (3)

  The rotor 100 moves at the same mechanical angular velocity with respect to both the inner peripheral side stator 200 and the outer peripheral side stator 300, and the number of poles for the field magnetic flux is also the same. The field magnetic flux interlinked with the armature winding 201 changes in proportion to the number of pole pairs of the inner peripheral side stator 200, and the field magnetic flux interlinked with the armature winding 301 is the number of pole pairs of the outer peripheral side stator 300. Changes in proportion to

  Therefore, when the number of pole pairs Pn of the inner peripheral side stator 200 and the number of pole pairs Pg of the outer peripheral side stator 300 are introduced, Expression (3) is expressed as Expression (4).

  Vn∝Pn · Φn, Vg∝Pg · Φg (4)

  Therefore, if the ratio between the number of pole pairs Pn and the number of pole pairs Pg is set equal to the ratio between the field magnetic flux magnitude Φg and the field magnetic flux magnitude Φn, the armature windings 201 and 301 are linked. The magnitude of the field magnetic flux is equal to the changing speed. The no-load induced voltages Vn and Vg can be set equal.

  As described above, in the double amateur motor, it is desirable that the no-load induced voltage is set equal in the two armatures, in particular, because the no-load rotation speed can be optimized. The reason for this will be described below.

  Even if the two armatures are driven by different power sources, for example, an inverter power source, the upper limit values of the voltages that can be output by the two power sources are equal to each other due to the reduction in production cost and the ease of production. If the no-load induced voltage in one armature is larger than that in the other armature, when the no-load induced voltage in one armature reaches the upper limit of the power supply voltage, the no-load induced in the other armature Although the induced voltage is small, it cannot be rotated at a higher speed. However, if the no-load induced voltages in the two armatures are equal, such a situation does not occur and the number of revolutions at no load can be maximized.

  The above is an explanation when there is no load, and when the armature winding is actually energized, in addition to this no-load induced voltage, an induced voltage for self-inductance for energizing the armature winding is superimposed. Become. However, since the ratio is extremely small compared with the no-load induced voltage, the above effect can be substantially obtained even when the field magnetic flux size and the number of pole pairs are selected in the above manner.

  In the configuration shown in FIG. 1, the number of pole pairs Pn of the inner side stator 200 and the number of pole pairs Pg of the outer side stator 300 are both 3, and are equal to each other. In this case, the ratio between the field magnetic flux magnitude Φ0n linked per turn of the armature winding 201 and the field magnetic flux magnitude Φ0g linked per turn of the armature winding 301. May be selected to be equal to the ratio between the number of turns Tg of the armature winding 301 and the number of turns Tn of the armature winding 201. This is because the following equation is established and the magnitudes Φn and Φg of the field magnetic flux linked to the armature windings 201 and 301 are equal.

  Φn = Tn · Φ0n, Φg = Tg · Φ0g (5)

  FIG. 2 is a cross-sectional view illustrating the structure of the double amateur motor according to the first embodiment of the present invention, and the number of pole pairs Pn and Pg are 3 and 6, respectively. Therefore, in this case, the ratio Φg / Φn of the magnitude of the field magnetic flux may be selected as 1/2 based on the equation (4).

  However, when the number of turns Tn and Tg is a positive integer and the magnitude of the field magnetic flux is difficult to strictly control, the expressions (4) and (5) may be established only approximately.

  3 and 4 are circuit diagrams illustrating an aspect in which the armature windings 201 and 301 are connected. Here, the case where the armature winding 201 is configured by three-phase coils 201U, 201V, and 201W, and the armature winding 301 is configured by three-phase coils 301U, 301V, and 301W, respectively.

  As described above, when the currents In and Ig are set to be equal, as shown in FIG. 3, the coil 201U has a coil 301U, the coil 201V has a coil 301V, and the coil 201W has a neutral point N. And each phase power supply.

  On the other hand, as shown in FIG. 4, the coil 201U may be connected in parallel to the coil 301U, the coil 201V may be connected to the coil 301V, and the coil 201W may be connected to the coil 301W.

  Further, the winding manner of the armature windings 201 and 301 may be concentrated winding or distributed winding. The winding mode may be different between the armature windings 201 and 301.

  The technique according to the present invention can be applied to, for example, a compressor that compresses a refrigerant by the electric motor and an electric motor that is employed in a blower that blows air by the electric motor. At least one of the compressor and the blower can be mounted on the air conditioner. Particularly, in-vehicle air conditioners are required to be downsized, and the present invention greatly contributes to this.

It is sectional drawing which illustrates the structure of the electric motor concerning embodiment of this invention. It is sectional drawing which illustrates the other structure of the electric motor concerning embodiment of this invention. It is a circuit diagram which illustrates the aspect in which an armature winding is connected. It is a circuit diagram which illustrates the aspect in which an armature winding is connected.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Rotor 101a Outer peripheral surface 101b Inner peripheral surface 200 Inner peripheral side stator 201, 301 Armature winding 300 Outer peripheral side stator

Claims (5)

A rotor (100) having a cylindrical shape including an outer peripheral surface (101a) and an inner peripheral surface (101b) and having a field magnet (102) for supplying a field magnetic flux;
An inner circumferential stator (200) around which the armature winding (201) is wound, facing the rotor from the inner circumferential surface side;
An outer peripheral stator (300) around which the armature winding (301) is wound, facing the rotor from the outer peripheral surface side;
The ratio of the number of pole pairs (Pn) of the inner circumference side stator and the number of pole pairs (Pg) of the outer circumference side stator, and the magnitude of the field magnetic flux interlinking with the armature winding of the outer circumference side stator The rotary electric machine is characterized in that the ratio between the thickness (Φg) and the magnitude of the field magnetic flux (Φn) interlinked with the armature winding of the inner peripheral side stator is selected to be equal. The number of pole pairs (Pn) of the inner circumference side stator (200) is equal to the number of pole pairs (Pg) of the outer circumference side stator (300),
The field magnetic flux magnitude (Φ0n) interlinked per turn of the armature winding of the inner peripheral side stator and the field interlinked per turn of the armature winding of the outer peripheral side stator The ratio to the magnitude (Φ0g) of the magnetic flux, the number of turns (Tg) of the armature winding of the outer peripheral side stator, and the number of turns (Tn) of the armature winding of the inner peripheral side stator The rotating electrical machine according to claim 1, wherein the ratio is selected to be equal.   The compressor which employ | adopts the rotary electric machine as described in any one of Claim 1 or Claim 2 as an electric motor, and compresses a refrigerant | coolant with the said electric motor.   A blower that employs the rotating electric machine according to claim 1 as an electric motor and blows air using the electric motor. An air conditioner equipped with at least one of the compressor according to claim 3 and the blower according to claim 4.

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