JPH0622390B2 - Commutatorless motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a small commutatorless electric motor used for electric equipment and the like.

(B) Prior art Generally, a commutatorless motor is shown in FIG.
No. 2836), the stator (1) is composed of teeth (2), (3), and (4) formed into three salient poles,
Each tooth is provided with three-phase stator windings (5), (6) and (7) consisting of U-phase, V-phase and W-phase. Further, a rotor (8) magnetized with two poles is provided at the center, and further, teeth (2) and teeth (3), teeth (3) and teeth (4),
Between the teeth (4) and the teeth (2), there are three Hall elements (9), (1) for position detection that detect the rotational position of the rotor (8).
0) and (11) (or position detecting means such as a search coil) are provided.

Incidentally, FIG. 2 shows a conventional example in which the rotor (12) is magnetized to have four poles, and the same components as those in FIG. 1 are designated by the same reference numerals.

In the above conventional example, first, the rotor (8) or (1
Three Hall elements (9), (10), and (11) were provided inside the electric motor to detect the rotational position of 2). Therefore, Hall elements (9), (10), (1
1), the stator windings (5), (6), (7) and the external lead wire were many in the connection portion, and the connection structure of the wiring was complicated. When the Hall elements (9), (10), (11) are not mounted properly, a detection error occurs with respect to the rotational position of the rotor (8) or (12), and the stator winding (5). , (6),
The energization switching timing of (7) is disturbed, and unnecessary acceleration / deceleration occurs during one rotation of the rotor, which deteriorates the operating efficiency and characteristics of the electric motor and causes vibration and noise due to acceleration / deceleration. .

Further, the Hall elements (9), (10), (11) are generally weak to heat, and there is a problem that this type of electric motor (for example, a compressor) cannot be used in a high temperature atmosphere, which deteriorates the versatility of the electric motor. There was a problem to do.

Further, in order to solve the above-mentioned problems, position detecting means such as Hall elements (9), (10), (11) are not provided, and three phases are always provided so that one phase is always de-energized during operation. An attempt was made to control the energization of the stator winding, and to sequentially switch the energization to the stator winding with a gate signal based on the change of the induced voltage in the non-energized stator winding. When used in a non-commutator motor with the structure shown in FIGS. 1 and 2 (however, the Hall element is removed), when the rotation speed decreases at low speed or due to a sudden overload, it is induced with the decrease in rotation speed. There is a problem that the voltage becomes low and the control device malfunctions, causing abnormalities such as step-out and lock.

Further, in such a commutatorless motor having the structure shown in FIGS. 1 and 2, when such energization control is performed, the stator windings (5), (6), ( Only two phases of 7) are always energized, and the rotating magnetic field generated in the rotor (8) or (12) is always within 180 degrees of the outer circumference of the rotor (8) or (12). Concentrate on. Therefore, the magnetic attraction force to the outer circumference of the rotor (8) or (12) is deviated to generate vibration and noise, and the weight due to the deviation is concentrated on a part of the bearing, and the life of the bearing is shortened. There was a problem. This problem is particularly noticeable in electric motors with high output such as fan motors.

(C) Purpose In view of the above points, the non-commutator motor according to the present invention, when controlling the energization switching to the stator winding by using the induced voltage generated in the non-energized stator winding, the rotor. The purpose is to increase the induced voltage during low speed rotation and to prevent bias of the rotating magnetic field generated from the stator.

(D) Configuration The present invention relates to a non-commutator motor having a rotor having a permanent magnet, a plurality of teeth for applying a rotating magnetic field to the rotor, and a three-phase stator winding wound around each tooth. , Combine the energization combinations of the stator windings so that there is always one non-energized phase, and energize the stator windings based on the induced voltage generated in the non-energized stator windings when the rotor rotates. And the number of teeth is set to 3 × n (n is an integer of 2 or more), and the stator winding has a different phase between adjacent teeth and is capable of full-wave energization. It should be connected.

Further, the plurality of teeth are configured as convex poles and the number of teeth is configured as 6 or 9.

(E) Embodiment An embodiment of the present invention will now be described with reference to FIGS. 3 to 6. In FIG. 3, (13) represents the teeth (14) to (19) of the six salient poles. Each of the teeth (14) to (19) is provided with stator windings (20) to (25) at 60 degree intervals.
Reference numeral (26) is a rotor which is magnetized to have four poles and has a rotation shaft provided at the center thereof.

FIG. 4 shows another embodiment in which the rotor (27) is magnetized to have eight poles, and the same components as those in FIG. 3 are designated by the same reference numerals.

Further, the stator windings (20) to (25) are star-connected as shown in FIG. 5 to form U-phase, V-phase and W-phase. As shown in FIG. 6, the currents to the respective phases are alternately flown to form a so-called full-wave energization system. Further, the stator windings (20) to (25) are connected so that the adjacent teeth have different polarities (different phases) during energization, and the facing and facing teeth have the same polarities (same phase).

Incidentally, (28) is a controller for generating a gate signal based on the change of the induced voltage generated in the non-energized stator winding to turn ON / OFF the switching elements (29) to (34). By controlling the switching element, FIG. 6 (U),
Energization control to the patterns U phase, V phase, and W phase as shown in (V) and (W) is performed.

In the non-commutator motor configured as described above, the stator has a pattern as shown in FIGS. 6 (U), (V), and (W), that is, a pattern in which only two of the three phases are always energized. Even if the energization of the winding is controlled, the number of teeth is set to 3 × n (n is an integer of 2 or more), and the phases of the teeth (14) to (19) are different from each other. Since it is configured, the distribution of the rotating magnetic field (magnetic attraction force) can be dispersed on the outer circumference of the rotor without deviation.

Further, the number of teeth is set to 3 × n (n is an integer of 2 or more),
By reducing the cross-sectional area of each tooth as compared with the conventional technique of three teeth as compared with the conventional technique, the number of windings of the stator winding in each tooth can be increased, and the induced voltage can be greatly extracted. . Therefore, a large induced voltage can be obtained even when the rotor rotates at a low speed, and it is possible to prevent malfunction of the control device and occurrence of abnormalities such as step-out and lock.

Further, if the number of teeth of the stator winding is set to 6 or 9, the wiring between the stator windings and the lead wires can be reduced as compared with an electric motor having 12 or more teeth, and the manufacturing process can be simplified, and the number of teeth can be reduced. Number 6
If the number of teeth is set to 9 or 9, an inexpensive and efficient electric motor can be obtained as compared with the case where the number of teeth is 12 or more, and the laminated thickness of the stator can be reduced to make the motor thinner. Since the teeth are convex poles, the winding of the stator winding can be easily automated and the manufacturing process can be further simplified.

Furthermore, by connecting the stator windings in a star connection (three-phase full-wave connection), the utilization ratio of the stator windings is higher than in the case where the stator windings are energized by half-wave, and the operating efficiency of the motor can be increased. it can. In particular, in a motor having a large output such as a fan motor, the improvement of operating efficiency can be effectively shown.

Hereinafter, an example of the energization control of the stator winding when the induced voltage is used (an example of the operation of the controller (28)) will be described with reference to FIGS. 5 and 6. The controller (28) turns on a non-energized stator winding, for example, switching elements (29) and (33).
The switching elements (30), (31), (32),
(34) is turned off and a current is passed from the U phase to the V phase (stator windings (20), (23), (22), (25)
The stator windings (21), (2
The induced voltage generated between the terminal (W) of 4) and the neutral point (N) changes as shown in FIG. 6 (w) (only the induced voltage changes when not energized). In this change in the induced voltage, the time (t) at which the voltage becomes zero, especially after the energization of the stator windings (21) and (24) is cut off (the switching element (34) is changed from ON to OFF) The switching elements (31) and (33) are turned on after a lapse of (t) time from the time when the induced voltage becomes zero, and the switching elements (29), (30), (32) and (34) are turned on. OFF
Then, a current is passed from the W phase to the V phase. At the same time, an induced voltage is used between the terminals (U) of the stator windings (20) and (23) and the neutral point (N) to perform switching elements (2) in the same manner as above.
9) to (34) are switched to the next state. Similarly, based on the induced voltages (FIGS. 6 (u), (v), (w)) generated in the non-energized stator winding, the values of FIG. 6 (U), (V), (W) are sequentially Rotate the rotor (2
6) or (27) is rotated.

(F) Effects As described above, the present invention does not include a rotor having a permanent magnet, a plurality of teeth that give a rotating magnetic field to the rotor, and a three-phase stator winding wound around each tooth. In a commutator motor, the energizing combination of the stator winding is always 1
The number of teeth is set to 3 × n based on the induced voltage generated in the non-energized stator winding when the rotor rotates.
(N is an integer of 2 or more) and the stator windings are connected in three phases so that adjacent teeth have different phases and full-wave energization is possible. By dividing the three-phase stator winding into multiple teeth, it is possible to prevent the magnetic attraction force from deviating to the rotor, reducing noise and extending the life of the bearing.

In addition, the induced voltage generated in the non-energized stator winding is U phase, V
Since it is used for switching between phase and W-phase energization, detection means (Hall element etc.) for detecting the rotational position of the rotor is not required, the electric motor can be downsized, the manufacturing process can be simplified, and the place where the electric motor is used. Thus, the regulation conditions such as temperature can be relaxed, and the versatility of this non-commutator motor can be improved.

Further, since the tooth width per one becomes smaller as the number of teeth of the stator increases, and the number of windings of the stator winding can be increased accordingly, a larger induced voltage can be taken out as compared with the conventional case. Therefore, a stable gate signal can be obtained even when the rotation speed is reduced at a low speed or when the load is rapidly increased, and the energization of the stator winding can be reliably controlled.

If each stator winding is star-connected in each phase of U, V, and W, a neutral point can be directly provided in the stator winding of the motor, so that an accurate change in induced voltage must be detected. Therefore, it is possible to accurately control the energization of the stator winding.

[Brief description of drawings]

1 and 2 are schematic views of a stator showing a conventional non-commutator motor, FIGS. 3 and 4 are schematic views of a stator showing an embodiment of the present invention, and FIG. 5 is a schematic view of the present invention. Schematic diagram showing the control device used in the electric motor, FIGS. 6 (U), (V), (W) are U,
Waveform diagram showing the energized state of each phase of V, W, the same figure (u),
(V) and (w) are waveform charts showing the induced voltage generated when the U, V, and W phases are not energized. (13) …… stator, (14) to (19) …… teeth,
(20) to (25) ... Stator winding.

Claims (2)

[Claims] 1. A non-commutator motor having a rotor having a permanent magnet, a plurality of teeth for applying a rotating magnetic field to the rotor, and a three-phase stator winding wound around each tooth. The energization combination of the child windings is combined so that one phase is always non-energized, and the energization combination of the stator windings is switched based on the induced voltage generated in the non-energized stator winding during rotation of the rotor. And the number of teeth is 3 × n (n is an integer of 2 or more), and the stator windings are three-phase connected so that adjacent teeth have different phases and full-wave energization is possible. A non-commutator motor characterized by the following. 2. The non-commutator motor according to claim 1, wherein the plurality of teeth are convex poles and the number of teeth is 6 or 9.