JP2000217290A - Electric motor - Google Patents

Abstract

(57) [Summary] [PROBLEMS] In an electric motor, a periodic excitation force generated by imbalance of an air gap (air gap) is suppressed to reduce vibration,
Reduce noise. SOLUTION: An electric motor is configured such that a winding having at least the same polarity is wound around a stator disposed outside a rotor having a magnet, at least for each phase, relative to the stator, thereby forming a predetermined number of phases. . Of the four-pole windings, the same-polarity windings are connected in parallel for each phase, and the parallel windings are connected in series to form a one-phase winding. For U phase, winding Ua and winding Uc
Are connected in parallel, the winding Ub and the winding Ud are connected in parallel, the winding circuits are connected in series, one end of this series circuit is connected to the lead terminal U, and the other end is connected to the neutral point. N1 and the V-phase windings Va, Vb, Vc, Vd and the W-phase windings Wa, Wb, Wc, Wd are connected in the same manner as the U-phase, and the motor windings are connected in a star connection system. Connecting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stator winding technique for a motor such as a brushless DC motor used in an air conditioner or the like, and more particularly, to noise and vibration suppression by connecting windings of each phase. The present invention relates to an electric motor.

[0002]

2. Description of the Related Art In an electric motor, a rotor 2 having a magnet is disposed inside a stator 1 as shown in FIG. 3 is a shaft. Further, the magnets of the rotor 2 are omitted because various shapes are already proposed.

The electric motor is a three-phase four-pole motor, and a stator (for example, 24 slots; groove) 1 has a winding (coil) U
Four windings are formed at a six-slot pitch for each phase, V phase and W phase.

The U-phase is wound around four windings Ua, Ub, Uc, Ud, and the V-phase is windings Va, Vb, Vc, Uc, which are three slots shifted from the U-phase windings Ua, Ub, Uc, Ud. V is wound, and the W phase is wound by windings Wa, Wb, Wc and Wd shifted from the V phase Va, Vb, Vc and Vd by three slots.

As shown by the solid arrows in FIG. 8, for U-phase windings Ua, Ub, Uc, and Ud, Ua and Uc are wound in the same direction (assuming the same polarity), and Ub and Ud are wound in the same direction. Then, Ua, Uc and Ub, Ud are wound in opposite directions (different poles). V-phase windings Va, Vb, Vc,
The windings Wa, Wb, Wc, Wd of the Vd and W phases are wound in the same direction. FIG. 8 corresponds to FIG. 7, and the numbers in the figure are slot numbers.

[0008] As shown in FIGS. 8 and 9, a star (star-shaped) connection system is adopted for the connection of the windings of each phase. In the case of this electric motor (hermetic motor), each phase is connected to each other. The windings are connected in series, one end of which is U-phase,
V-phase and W-phase lead terminals U, V, W are connected to each other, and the other end is connected to a neutral point N.

When the electric motor is driven by an inverter system, that is, when the winding of each phase is energized, for example, U → W, V → W, V → U, W → U, W → V, U → If the operation is repeated in the order of V, a rotating magnetic field is generated, and a rotating force is generated in the electric motor.

[0008]

By the way, in the electric motor, a periodic excitation force is generated due to the eccentricity of the windings of the rotor 2 and the stator 1, that is, the imbalance of the air gap (air gap). Excitation force generates motor noise and vibration.

For example, when a small air gap or a large air gap is generated due to the axial deviation of the shaft 3 of the rotor 2, the current I flowing through the windings in the magnetic poles of the small portion and the permanent magnet of the rotor 2 The force acting between the magnetic flux and the current I flowing through the winding at the large magnetic pole
And the force acting between the permanent magnet of the rotor 2 and the magnetic flux. Moreover, it fluctuates both temporally and spatially. As a result,
Exciting forces act on the stator 1 and the rotor 2 in directions opposite to each other, and this causes vibration and noise.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to suppress a periodic excitation force generated due to an imbalance of a gap (air gap), and to suppress vibration and noise. An object of the present invention is to provide an electric motor as described above.

[0011]

In order to achieve the above object, in the electric motor of the present invention, a stator disposed outside a rotor having a magnet has at least a 2P pole (P; positive; In the electric motor, the windings forming the integers are wound in parallel, and the windings having the polar position relationship facing each other among the windings forming each phase are connected in parallel. I have.

According to the present invention, a predetermined number of phases are formed on a stator disposed outside a rotor having a magnet by winding a winding having the same polarity at least for each phase relative to the stator. In the electric motor, the windings having the same polarity are connected in parallel for each phase among the windings constituting the 2P poles (P; positive integer) of each phase, and the parallel windings are connected in series. It is characterized in that the coils are connected to form a one-phase winding, and the winding of each phase is wound in parallel with the stator and connected in parallel.

According to the present invention, a predetermined number of phases are formed on a stator disposed outside a rotor having a magnet by winding windings having the same polarity at least for each phase relative to the stator. 2P pole of each phase (P; positive integer)
Of the windings that constitute the above, all the windings for each phase are connected in parallel to form a single-phase winding, and the winding for each phase is wound relative to the stator. It is characterized by being connected in parallel.

It is preferable that the windings of each phase wound around the stator are connected in a star connection system or a delta connection system.

[0015] Further, the stator is suitable as a rotor of a brushless DC motor and / or a reluctance motor.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to FIGS. In the figure,
7 to 9 are denoted by the same reference numerals, and redundant description will be omitted. See also FIG. 7 for stator windings.

In the electric motor of the present invention, for example, the windings (coils) of the respective phases shown in FIG. It is noted that the current of the winding (the winding connected in parallel) changes (to a value other than の of the conduction current I), and the exciting force due to air gap unbalance or the like is suppressed.

Therefore, as shown in FIGS. 1 and 2,
The stator of the motor has windings (coils) of 2P poles (P = 2; positive integer) wound around each phase as in FIG.
Phase windings Ua, Ub, Uc, Ud, V phase windings Va, V
b, Vc, Vd and W-phase windings Wa, Wb, Wc, W
Among the windings d, the windings at opposite positions for each phase are connected in parallel, and the windings connected in parallel are connected in series to form a single-phase winding.

For the U-phase winding, the winding Ua and the winding U
c, and the windings Ub and Ud are connected in parallel, and the windings Ua and Uc connected in parallel with these windings Ub and Uc are connected in parallel.
and d are connected in series.

Similarly, for the V-phase winding, the winding Va
And the winding Vc, and the winding Vb and the winding Vd are connected in parallel, and the windings Va and Vc connected in parallel and the windings Vb and Vd connected in parallel are connected in series.

For the W-phase winding, winding Wa and winding W
c, and the winding Wb and the winding Wd are connected in parallel, and the windings Wa and Wc connected in parallel with these windings Wb and Wd are connected in parallel.
and d are connected in series.

In the case of the star (star) connection method, the other terminals of the windings Ua and Uc connected in parallel are connected to the U-phase lead terminals U.
The other terminals of the windings Ub and Ud connected in parallel are connected to the neutral point N1.
Then, the other terminals of the windings Va and Vc connected in parallel are connected to the V-phase lead terminal V. Further, the windings Vb,
The other terminal of Vd is connected to the neutral point N1, and the windings Wa, W
The other terminal c is connected to the W-phase lead terminal W, and the other terminals of the parallel-connected windings Wb and Wd are connected to the neutral point N1.

Here, when the total resistance value of each phase in the conventional example is 4r (when the resistance value of each winding is r), the resistance value of each winding in the present invention is set to 4r, so that the conventional method can be used. The same characteristics as the electric motor can be obtained.

When the current flowing through the motor winding is I, the motor voltage V is E + IR. E is a back electromotive force generated in the motor winding, and R is a resistance value of the motor winding.

Therefore, if the current flowing through the windings Ua, Uc connected in parallel is I, a current of I / 2 flows through each winding Ua, Uc, while the back electromotive force E is generated by the magnet of the rotor 2. Then, Eu + (I / 2) · 4r is established in each of the windings Ua and Uc. Eu is a back electromotive force.

The back electromotive force is not only proportional to the rotation speed of the rotor 2 but also varies depending on the size of the air gap. Therefore, if the rotor 2 is unbalanced (is eccentric), for example, if the air gap on the winding Ua side is larger than the air gap on the winding Uc side, the winding Ua at the larger portion
Is smaller than the back electromotive force Eub generated in the winding Uc at a small portion. Then, the winding U
Regarding a and Uc, Eua + Ia · 2r = Eub + Ib
2r holds. In this equation, since Eua <Eub, Ia> Ib, and Ia> I / 2, Ib
<I / 2.

The foregoing also applies to other parallel connected windings of the same phase and to parallel connected windings of other phases.

As described above, when the currents flowing through the windings Ua and Uc connected in parallel are different, the torque proportional to the product of the current and the magnetic flux changes. In other words, the torque increases on the winding Ua side (a place where the air gap is large), while the torque decreases on the winding Uc side (a place where the air gap is small). In other words, the force acting between the current flowing through the winding Ua and the magnetic flux generated by the magnet of the rotor 2 increases, acting to correct the imbalance of the rotor 2 and reducing the periodic excitation force. Reduce motor noise and vibration.

Also, regarding the reluctance, which is the imaginary part of the impedance of the winding, the influence of the magnetic flux generated by the windings Ua and Uc on the magnetic flux generated by the magnet of the rotor 2 is averaged, and the balance of the force generated by the difference in the reluctance is improved. It contributes to the suppression of motor noise and vibration.

In this embodiment, the windings Ua, Ua
Although c has been described, the same effect is produced for other parallel-connected windings, and therefore, description thereof will be omitted.
Further, the same effect can be obtained even if a portion having a large air gap and a portion having a small air gap are between the windings.

FIGS. 3 and 4 are a schematic motor equivalent circuit diagram and a schematic winding schematic diagram for explaining another embodiment of the present invention. In the drawings, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description will be omitted.

In the motor of this embodiment, the U-phase winding U
a, Ub, Uc, Ud are all connected in parallel. One of these terminals is connected to the U-phase lead terminal U, and the other terminal is connected to the neutral point N2.

The same connection is made for the V phase and the W phase. That is, the windings Va, Vb, Vc, and Vd are all connected in parallel. One terminal is connected to the V-phase lead terminal V, and the other terminal is connected to the neutral point N2. The windings Wa, Wb, Wc, Wd are all connected in parallel. One terminal is connected to the W-phase lead terminal W, and the other terminal is connected to the neutral point N2.

Here, when the total resistance value of each phase in the conventional example is 4r (when the resistance value of each winding is r), the resistance value of each winding in the present invention is set to 16r, and the conventional resistance is set to 16r. The same characteristics as the electric motor can be obtained. As described above, the windings Ua, Ub,
If the current flowing through the resistance circuits of Uc and Ud is I, a current of I / 4 flows through each of the windings Ua, Ub, Uc and Ud, while the back electromotive force E is generated by the magnet of the rotor 2.
Occurs, and Eu + (I / 4) · 16r is established in each of the windings Ua, Ub, Uc, and Ud.

The back electromotive force varies not only in proportion to the rotation speed of the rotor 2 but also in accordance with the size of the air gap. Therefore, similarly to the above-described embodiment, if the rotor 2 is unbalanced (is eccentric), for example, if the air gap on the winding Ub side is larger than the air gap on the winding Ud side, the large portion Back electromotive force Eu generated in winding Ub
b is smaller than the back electromotive force Eud generated in the winding Ud at a small location. Then, regarding the windings Ub and Ud, Eu
b + Ib · 4r = Eud + Id · 4r is established. In this equation, since Eub <Eud, Ib> I
d, that is, Ib> I / 2 and Id <I / 2.

The foregoing also applies to in-phase parallel connected windings and other phase parallel connected windings.

As described above, for example, the winding U connected in parallel
When the currents flowing through b and Ud are different, the torque proportional to the product of the current and the magnetic flux changes. In other words, the torque increases on the winding Ub side (a location where the air gap is large), while the torque decreases on the winding Ud side (a location where the air gap is small). In other words, the force acting between the current flowing through the winding Ub and the magnetic flux generated by the magnet of the rotor 2 increases, acting to correct the imbalance of the rotor 2 and reducing the periodic excitation force. , Reduce motor noise and vibration.

Also, regarding the reluctance, which is the imaginary part of the impedance of the winding, the influence of the magnetic flux by the windings Ub and Ud on the magnetic flux by the magnet of the rotor 2 is averaged, and the balance of the force generated by the difference in the reluctance is balanced. It contributes to the suppression of motor noise and vibration.

In this embodiment, the windings Ub, Ub
Although d has been described, the same effect occurs in the in-phase parallel-connected winding and the other-phase parallel-connected winding.
The description is omitted. In addition, the above-described effect is exhibited even when a portion where the air gap is large and a portion where the air gap is small are between the windings.

FIGS. 5 and 6 are schematic motor equivalent circuit diagrams showing modifications of the above-described embodiment and other embodiments. In the drawings, the same portions as those in FIGS. 2 and 3 are denoted by the same reference numerals, and redundant description will be omitted.

FIG. 5 is a winding circuit diagram employing a delta connection system instead of the star connection system shown in FIG. 2, and FIG. 6 is a winding circuit diagram employing a delta connection system instead of the star connection system shown in FIG. It is a line circuit diagram. It should be noted that it is already known that the same drive control as in the star connection method can be performed even in the delta connection method, and it is clear that the same effects as in the above-described embodiment and other embodiments can be exhibited. Therefore, description of the connection relation and the like will be omitted.

Furthermore, if the above-described rotor is applied to a brushless DC motor or a reluctance motor as a compressor motor of an air conditioner, for example, if it is used as a compressor motor of an air conditioner, the connection of windings is made. In this case, the performance of the air conditioner can be improved (particularly, vibration and noise can be reduced) without increasing the cost.

[0043]

As described above, according to the first aspect of the present invention, the stator arranged outside the rotor having the magnet has at least 2P poles (P; positive; In the electric motor in which the windings constituting the integers are wound, among the windings constituting each phase, the windings having a relative positional relationship for each phase are connected in parallel, so that the rotor is eccentric. However, even if a portion having a large air gap and a portion having a small air gap occur (even if an air gap becomes unbalanced), the current of the winding changes depending on the size of the air gap. Therefore, not only does the torque proportional to the product of the current and the magnetic flux change, but also the torque at a location where the air gap is large increases, and the periodic excitation force generated due to the imbalance of the air gap (air gap) can be suppressed. .
Further, since the reluctance is balanced, there is an effect that motor vibration and noise can be suppressed.

According to the second aspect of the present invention, at least one winding having the same polarity for each phase is wound around the stator disposed outside the rotor having the magnet, relative to the stator.
In a motor having a predetermined number of phases, 2P of each phase
Of the windings constituting the pole (P; positive integer), the windings of the same polarity are connected in parallel for each phase, and the parallel windings are connected in series to form a one-phase winding. Since the winding of each phase is wound in parallel with the stator and connected in parallel, even if the rotor is eccentric and large and small air gaps are generated ( Even if air gap imbalance occurs), the current of the winding changes depending on the size of the air gap. Therefore, not only does the torque proportional to the product of the current and the magnetic flux change, but also the torque at the location where the air gap is large increases, and the periodic excitation force generated due to the imbalance of the air gap (air gap) can be suppressed. . In addition, since the reluctance is balanced, motor vibration and noise can be suppressed. Further, for example, in the case of a three-phase four-pole motor, if the resistance of each winding is set to 4r (four times the previous winding r), the effect that the characteristics of the electric motor need not be changed can be obtained.

According to the third aspect of the present invention, at least one winding having the same polarity for each phase is wound around the stator disposed outside the rotor having the magnet, relative to the stator.
In a motor having a predetermined number of phases, 2P of each phase
Of the windings constituting the poles (P: positive integer), all windings are connected in parallel for each phase to form a single-phase winding, and the winding for each phase is relative to the stator. Since the wound windings are connected in parallel, even if the rotor is eccentric and large and small air gaps occur (even if air gap imbalance occurs), the air The current of the winding changes depending on the size of the gap. Accordingly, not only does the torque proportional to the product of the current and the magnetic flux change, but also the torque at a location where the air gap is large increases, and the periodic excitation force generated due to the imbalance of the air gap (air gap) is suppressed. be able to. Further, since the reluctance is balanced, motor vibration and noise can be suppressed. Further, in the case of a three-phase four-pole motor, for example, if the resistance of each winding is set to 16r (16 times that of the previous winding r), there is an effect that the characteristics of the electric motor do not change.

According to the invention set forth in claim 4, according to claim 1,
In 2 or 3, each phase winding wound around the stator is connected by a star connection method or a delta connection method, so that the conventional connection method is adopted in addition to the effects of claim 1, 2, or 3. To control the energization.

According to the invention set forth in claim 5, claim 1,
In 2, 3, or 4, the stator is a brushless DC
Since it is incorporated in a motor and / or a reluctance motor, in addition to the effects of claims 1, 2, 3 or 4, if it is used as, for example, a compressor motor of an air conditioner, the cost can be increased without increasing the cost. The performance of the harmony device can be improved (particularly, vibration and noise can be reduced).

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention and is a schematic diagram for explaining winding connection of an electric motor.

FIG. 2 is a schematic motor equivalent circuit diagram for explaining the electric motor shown in FIG.

FIG. 3 is a schematic motor equivalent circuit diagram of an electric motor illustrating another embodiment of the present invention.

FIG. 4 is a schematic diagram of a winding explaining the electric motor shown in FIG. 3;

FIG. 5 is a schematic diagram of a winding explaining a modification of the embodiment shown in FIGS. 1 and 2;

FIG. 6 is a schematic diagram of a winding explaining a modification of the embodiment shown in FIGS. 3 and 4;

FIG. 7 is a schematic plan view for explaining a conventional electric motor.

FIG. 8 is a schematic diagram of a winding of the electric motor shown in FIG. 7;

FIG. 9 is a schematic motor equivalent circuit diagram of the electric motor shown in FIG. 7;

[Explanation of symbols]

 1 Stator 2 Rotor N, N1, N2 Neutral point U Lead terminal (U-phase) Ua, Ub, Uc, Ud Winding (U-phase coil) V Lead terminal (V-phase) Va, Vb, Vc , Vd winding (V-phase coil) W Lead terminal (W-phase) Wa, Wb, Wc, Wd winding (W-phase coil)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Satoshi Tsukamoto 1116, Suenaga, Takatsu-ku, Kawasaki-shi, Kanagawa F-term in Fujitsu General Limited (Reference) 5H019 AA06 DD04 DD09 DD10 EE14 5H603 AA01 BB01 BB10 BB12 CA01 CA05 CB05 CB23 CC04 CC11 CD05 CE01 CE13

Claims (5)

[Claims] An electric motor in which a stator disposed outside a rotor having a magnet is wound with a winding constituting at least a 2P pole (P: positive integer) for each phase.
An electric motor characterized in that, among windings constituting each phase, windings having a pole position relationship facing each other are connected in parallel. 2. A predetermined number of phases are formed on a stator disposed outside a rotor having a magnet by winding a winding having the same polarity at least for each phase relative to the stator. In the electric motor, among the windings constituting the 2P poles (P; positive integer) of each phase, the windings of the same polarity are connected in parallel for each phase, and the parallel windings are connected in series. A single-phase winding, and a winding connected to the stator with respect to the winding for each phase is connected in parallel. 3. A predetermined number of phases are formed on a stator arranged outside a rotor having a magnet by winding a winding having the same polarity at least for each phase relative to the stator. In the electric motor, among the windings constituting the 2P poles (P; positive integer) of each phase, all the windings are connected in parallel for each phase to form a single-phase winding, and the winding for each phase is formed. An electric motor, wherein windings wound relative to the stator with respect to wires are connected in parallel. 4. The electric motor according to claim 1, wherein the windings of the respective phases wound on the stator are connected in a star connection system or a delta connection system. 5. The electric motor according to claim 1, wherein said stator is incorporated in a brushless DC motor and / or a reluctance motor.