JP4039074B2 - Synchronous motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in torque performance, a longer life, and an improvement in workability of winding work, particularly in a synchronous motor.
[0002]
[Prior art]
In conventional synchronous motors, the number of slots in the stator core and the number of permanent magnet magnetic poles in the rotor are generally 12 slots, 8 poles, 9 slots, 8 poles, and the like.
[0003]
However, in the case of 12 slots and 8 poles, the magnetic pole width of one magnetic pole tooth and the pitch of the permanent magnet magnetic poles are separated from each other, so that the winding coefficient is reduced and the motor efficiency is lowered. The generation order of the cogging torque determined by the least common multiple of the number of magnetic poles is as small as 24, and the cogging torque is increased.
[0004]
In the case of 9 slots and 8 poles, the winding currents of the U, V, and W phases flowing through the magnetic teeth are not the same at each time point, so the combined attractive force in the radial direction is not zero, and a magnetic attractive force is always generated in the rotor. As a result, the bearings such as ball bearings are subject to eccentric force in the radial direction, shortening the bearing life, and the phase of the induced voltage generated in each magnetic tooth is different, so the parallel winding of the stator winding There was a problem that the wire diameter of the winding could not be increased and workability was poor.
[0005]
[Problems to be solved by the invention]
On the other hand, in direct drive motors that directly drive loads without using a speed reducer in elevator motors or robot motors, a large torque is required. Many optimizations of the number of slots and the number of rotor magnetic poles have been proposed (see, for example, Japanese Patent Laid-Open No. 2000-201462). The number n of magnetic pole teeth is set to 18 × (1 + Z), and the number m of permanent magnet magnetic poles is set to 16 × (1 + Z) (where Z is an integer of 1 or more), thereby reducing cogging torque and winding. The line coefficient is improved.
[0006]
However, while the magnetic pole teeth are 18 and the permanent magnet magnetic poles are 16, the greatest common divisor between the magnetic teeth number n and the permanent magnet magnetic pole number m is 4 because the greatest common divisor 2 is multiplied by at least 2 (1 + Z). Thus, the least common multiple is smaller than that of the greatest common divisor of 2 or 3, and the generation order of cogging torque is also reduced.
[0007]
In other words, the cogging torque did not decrease so much despite the large number of magnetic teeth and the number of permanent magnet magnetic poles.
[0008]
Therefore, when the motor described above is used in an application that is used in a low-speed rotation region such as an elevator drive device, it is desired to reduce it as much as possible because torque ripple including cogging torque becomes a vibration source.
[0009]
The present invention solves such a conventional problem, and an object of the present invention is to provide a synchronous motor with a small cogging torque, a high magnetic flux utilization factor, a long bearing life of the motor, and an easy winding operation. And
[0010]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a magnetic core teeth and S stator cores that are circumferentially arranged at approximately equal intervals, a concentrated winding on each of the magnetic pole teeth, and three-phase Y A stator winding that is connected, and a rotor having P permanent magnet magnetic poles that have a gap in the circumferential direction and the N and S poles arranged alternately at substantially equal intervals, and the stator winding. Assuming that the number of parallel circuits of Y-connection of wires is 2, the number S of magnetic pole slots is 18, and the number P of permanent magnet magnetic poles is 20, three consecutive ones of 18 magnetic teeth are set as one phase. the sequentially arranged, the set of stator windings, in which the winding direction of the even-numbered pole tooth is wound such that the winding direction opposite to the odd pole tooth.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
In order to solve the above-described problem, the synchronous motor according to claim 1 is concentrated on the magnetic pole teeth and the stator core having S slots arranged in a circumferential manner at approximately equal intervals, and on each of the magnetic pole teeth. A stator winding wound and three-phase Y-connected, and a rotor having P permanent magnet magnetic poles having a gap in the circumferential direction with the magnetic pole teeth and having N and S poles alternately arranged at substantially equal intervals; When the number of parallel circuits of the Y connection of the stator winding is 2, the number S of the magnetic pole slots is 18, and the number P of the permanent magnet magnetic poles is 20, three consecutive ones of the 18 magnetic teeth 3 phase was sequentially arranged as a phase set, the set of stator windings, the winding direction of the even-numbered pole tooth is wound such that the winding direction opposite to the odd pole tooth Is.
[0012]
The synchronous motor of the mounting serial to claim 2, a parallel circuit number of Y-connection of the stator winding 2, the number S of the pole slot 30, when the number P of the permanent magnet magnetic pole 32, 30 Of three magnetic teeth are arranged in sequence, and one set of stator windings is wound around the odd-numbered magnetic teeth. Wrapped in the opposite direction.
[0013]
Further, in the synchronous motor according to claim 3, when the number of parallel circuits of the Y connection of the stator winding is 2, the number S of the magnetic pole slots is 42, and the number P of the permanent magnet magnetic poles is 44, 7 consecutive magnetic pole teeth are arranged as a single phase, and three phases are sequentially arranged. In the one set of stator windings, the winding direction to the even-numbered magnetic teeth is the winding direction to the odd-numbered magnetic teeth. is obtained by winding such that the opposite and.
[0014]
By setting in this way, the magnetic flux utilization factor (winding coefficient) can be increased. In addition, since the least common multiple of the number of magnetic pole slots and the number of permanent magnet magnetic poles can be increased (the generation order of cogging torque is increased), the cogging torque can be reduced.
[0015]
When the number of parallel circuits is 2, the direction of the winding currents of the U, V, and W phases wound around the opposing magnetic teeth is set symmetrically, so the combined attractive force in the radial direction becomes 0, and the rotor is magnetically The suction force does not work. Therefore, the bearing life is not adversely affected, and a long-life synchronous motor can be obtained .
[0016]
In addition, by setting the number of Y-connected parallel circuits to 2, there is no need to use a thick copper wire for the stator winding, and the proportion of the winding in the slot of the magnetic teeth (winding space factor) is improved. To do. Further, in one set of stator windings, winding is performed so that the winding direction of the even-numbered magnetic teeth is opposite to the winding direction of the odd-numbered magnetic teeth, so that continuous winding is possible. The workability of work and line processing is improved, and the man-hour can be reduced.
[0017]
【Example】
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0018]
Example 1
In the first embodiment, S = {3 × (2n + 1) × N}, P = {3 × (2n + 1) +1} × N, where n = 1 and N = 2 (the number of magnetic pole slots S = 18, permanent magnet magnetic poles) A number P = 20) synchronous motor will be described.
[0019]
In FIG. 1, reference numeral 1 denotes a stator, which includes 18 magnetic pole teeth 1a divided at equal intervals in the circumferential direction. Reference numeral 2 denotes a rotor, which includes a permanent magnet 2a. The outer peripheral surface of the permanent magnet 2a is magnetized so as to alternately have N and S poles at equal intervals.
[0020]
In the stator 1, slots 1b are formed between adjacent magnetic teeth 1a, and windings (not shown) in which the magnetic teeth 1a are wound in a concentrated manner are accommodated in the spaces of the slots 1b.
[0021]
U, V, and W represent the three phases of the stator winding, and the U, V, and W phases are sequentially arranged with three consecutive magnetic pole teeth as one set. In order to increase the magnetic utilization rate, the windings at the opposite positions are set in phase and the current direction is the same. For this reason, winding is performed such that the winding direction of the second winding of the three consecutive magnetic teeth is opposite to the winding direction of the first and third windings (the bar on the letter indicates the winding) It shows that the winding direction is reverse).
[0022]
As a result, the directions of the winding currents of the U, V, and W phases wound around the opposing magnetic teeth can be made symmetric, so that the combined attractive force in the radial direction becomes zero, and the magnetic attractive force does not act on the rotor, resulting in a bearing life. There is no adverse effect, and a long-life synchronous motor can be obtained.
[0023]
In addition, since the number of parallel circuits is two, there is no need to use a thick copper wire for the stator winding, the winding work can be facilitated and the winding space factor can be improved. Man-hours can be reduced.
[0024]
Furthermore, if three consecutive magnetic pole teeth are formed without being divided for each magnetic pole tooth, one set of stator windings can be continuously wound without being cut halfway. This reduces the number of man-hours for the wiring process.
[0025]
A connection diagram of the wound three-phase winding is shown in FIG. 2. Three consecutive windings are set as one set, and two sets facing each other are connected in parallel to form U, V, and W phases. Is Y-connected.
[0026]
Here, the synchronous motor of the present invention (the number of magnetic pole slots S = 18, the number of permanent magnet magnetic poles P = 20) and the conventional motor (S = 12, P = 8 and S = 9, P = 8) are combined with a stator. The results of comparing the cogging torque and induced voltage of the motor analyzed with the same inner diameter and outer diameter, permanent magnet inner diameter and outer diameter, and magnet material, and the cogging torque order and winding coefficient as substitute characteristics Table 1 shows.
[0027]
[Table 1]
[0028]
The cogging torque order is the least common multiple of the magnetic pole slot number S and the permanent magnet magnetic pole number P, the cogging torque is inversely proportional to the least common multiple of the cogging torque order, and the result of the winding coefficient (flux utilization factor) is the value of the induced voltage. As shown, the larger the value of the induced voltage, the higher the winding space factor and the more efficiently the magnetic flux of the permanent magnet is used. In other words, a large torque can be generated efficiently.
[0029]
In the analysis values, the cogging torque of the synchronous motor of the present invention is the smallest, the induced voltage is large, and good results are obtained.
[0030]
(Example 2)
In the second embodiment, among S = {3 × (2n + 1) × N}, P = {3 × (2n + 1) +1} × N, (n = 1, 2, 3, N = 2, 3), n = The description will focus on a synchronous motor at 1, N = 3.
[0031]
In FIG. 3, the stator 31 is provided with 27 magnetic pole teeth 31a and slots 31b at equal intervals in the circumferential direction, and the rotor 32 has N and S poles alternately on the outer peripheral surface of the permanent magnet 32a at equal intervals. 30 poles are magnetized. Here, the description will focus on the number of parallel circuits different from the first embodiment.
[0032]
Similarly to the first embodiment, U, V, and W are repeatedly arranged three times with one set of three consecutive magnetic teeth. In the second embodiment, in order to increase the magnetic utilization factor, the winding at the mechanical angle of 120 ° is set to have the same phase and the same current direction, so the second winding of the three consecutive magnetic pole teeth. Is wound so that the winding direction is opposite to the winding direction of the first and third windings. For the connection of the wound three-phase winding, one set of three consecutive windings and three sets separated by 120 ° in mechanical angle are connected in parallel to form U, V, and W phases. Connect the wires (Fig. 4).
[0033]
Here, substitution in each combination in the range of S = {3 × (2n + 1) × N}, P = {3 × (2n + 1) +1} × N, (n = 1, 2, 3, N = 2, 3) Table 2 shows a comparison list of cogging torque orders and winding coefficients as characteristics.
[0034]
[Table 2]
[0035]
As can be seen from Table 2, the winding coefficient is not related to the number of parallel circuits in the formula of the present invention, and depends on the value of n. If the set value of n is increased, the winding coefficient is improved. . Further, the cogging torque order increases in proportion to the number of parallel circuits, and the cogging torque can be reduced.
[0036]
In addition, although Example 1 and Example 2 demonstrated the case where the number N of parallel circuits when n = 1 was 2 and 3, when n = 2 in S = {3 × (2n + 1) × N} In order to increase the magnetic utilization rate, five consecutive magnetic teeth are set as one set, and the winding direction of the even-numbered winding of the five consecutive magnetic teeth is opposite to the winding direction of the odd-numbered winding. What is necessary is just to wind. When n = 3, winding is performed so that the winding direction of the even-numbered windings of the seven consecutive magnetic pole teeth is opposite to the winding direction of the odd-numbered windings. At this time, the magnetic pole teeth may be divided for each set (3, 5 or 7) of magnetic pole teeth.
[0037]
When the number of parallel circuits is 2, two in-phase pairs of magnetic pole teeth facing each other are connected in parallel. When the number of parallel circuits is 3, three sets of in-phase with a mechanical angle of 120 ° are connected in parallel. V and W phases may be used, and three phases may be Y-connected (the number of sets of consecutive magnetic teeth only changes from 3 to 5 or 7 and is not shown).
[0038]
By the way, in the case of the number of magnetic pole slots = 36 and the number of permanent magnet magnetic poles = 32 disclosed in the prior art (Japanese Patent Laid-Open No. 2000-201462), the order of the cogging torque is 288, and the structure of the present invention is relatively close. Compared with, the number of permanent magnet magnetic poles is 32, which is the same, and although the number of magnetic pole slots is as small as 30, the cogging torque order is as large as 480, and it can be seen that the cogging torque can be reduced.
[0039]
Further, when setting the number of magnetic pole teeth, the number of permanent magnet magnetic poles, and the number of parallel circuits of the present invention, they are appropriately selected according to the required external dimensions and characteristics of the motor. For example, the number of magnetic teeth is narrowed down from the required motor outer diameter, and the winding coefficient and cogging torque (the least common multiple of the magnetic teeth and permanent magnet magnetic poles = cogging torque order) are considered based on the rotational speed used and the magnitude of the desired torque. To set. Rather than setting the number N of parallel circuits from 2 to 3, fixing the number N of parallel circuits to 2 and setting n one larger can improve both the winding coefficient (magnetic utilization factor) and the cogging torque. Note that the winding diameter to be used is considered in determining the number of parallel circuits.
[0040]
【The invention's effect】
As is clear from the above-described embodiment, according to the present invention, the number of parallel circuits of the Y connection of the stator winding is set to 2, and the number of magnetic teeth and the number of permanent magnet magnetic poles are set to a specific relationship, thereby cogging. The torque order can be increased and the cogging torque can be reduced.
[0041]
Also, U and connect the even-numbered and a plurality of sets of in-phase with the odd winding direction reversed one phase pair of windings continues with the parallel, V, W-phase city, 3 phase is Y connection Thus, the magnetic flux utilization factor can be increased. Further, since the radial attractive force applied to the rotor during rotation can be balanced, the bearing life is not adversely affected, and a long-life synchronous motor can be obtained.
[0042]
In addition, since the number of parallel circuits of the three-phase winding is set to 2, it is not necessary to use a thick copper wire as the winding, so that the workability of the winding is improved and the work man-hour can be reduced. Moreover, the winding space factor can be improved.
[0043]
Furthermore, it is possible to more effectively reduce the cogging torque by the number of parallel circuits 2.
[0044]
Thus, a synchronous motor with a small cogging torque, a high magnetic flux utilization factor, a long bearing life of the motor, and an easy winding work can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part of an electric motor according to a first embodiment of the present invention. FIG. 2 is a connection diagram of the electric motor according to a first embodiment of the present invention. ] Connection diagram in Example 2 of the present invention [Explanation of symbols]
1,31 Stator 1a, 31a Magnetic teeth 1b, 31b Slot 2, 32 Rotor 2a, 32a Permanent magnet

Claims (3)

A stator core having S magnetic pole teeth and S slots arranged circumferentially at approximately equal intervals, a stator winding concentratedly wound on each of the magnetic pole teeth and three-phase Y-connected, and the magnetic pole teeth And a rotor having P permanent magnet magnetic poles having a gap in the circumferential direction and alternately arranged N and S poles at substantially equal intervals, and the number of parallel circuits of Y connection of the stator windings is 2, When the number S of slots is 18 and the number P of permanent magnet magnetic poles is 20, three of the 18 magnetic teeth are consecutively arranged as one set, and the three phases are sequentially arranged. The line is a synchronous motor wound so that the winding direction of the even-numbered magnetic teeth is opposite to the winding direction of the odd-numbered magnetic teeth . When the number of parallel circuits of the Y connection of the stator winding is 2, the number S of the magnetic pole slots is 30, and the number P of the permanent magnet magnetic poles is 32, one set of five consecutive ones of the 30 magnetic pole teeth. 3 phase was sequentially arranged as, the set of stator windings, 請 Motomeko 1 winding direction of the even-numbered pole tooth is wound such that the winding direction opposite to the odd pole tooth The synchronous motor described in 1. When the number of parallel circuits of the Y connection of the stator winding is 2, the number S of the magnetic pole slots is 42, and the number P of the permanent magnet magnetic poles is 44, 7 consecutive ones of 42 magnetic teeth are set in one phase. 3 phase was sequentially arranged as, the set of stator windings, 請 Motomeko 1 winding direction of the even-numbered pole tooth is wound such that the winding direction opposite to the odd pole tooth The synchronous motor described in 1.