JPH0417023B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotating field type cylindrical field station rotary electric machine, and particularly to improvements in the field winding thereof.

In so-called natural commutation non-commutator motors, which use the induced voltage of the synchronous motor to commutate the thyristor on the inverter side of the thyristor power converter, the leakage reactance of the armature circuit is reduced, and the thyristor It is well known that a damper winding must be provided on the field pole side in order to shorten the overlapping time of commutations. On the other hand, as a synchronous motor for conventional non-commutator motor equipment,
Salient-pole synchronous machines or cylindrical machines such as turbine generators are often used, but the former has a complicated magnetic pole structure, is time-consuming and expensive to manufacture, and cannot be manufactured at high speeds. There are other problems. Further, although the latter type is suitable for high speeds, it has drawbacks such as not being able to provide a sufficiently large number of brake windings, and being difficult to hold the rotor coil ends and being expensive.

By the way, as a type of synchronous motor, both the stator and rotor are equipped with three-phase windings, and during the starting period it functions as a wound induction motor, and near synchronous speed,
There is a so-called induction synchronous motor that is used as a synchronous motor by passing a direct current through a rotor side winding. In this induction synchronous motor, the rotor windings are arranged uniformly around the entire circumference, and the coil ends are made into a cylindrical shape by using two layers of winding, and the coil ends can be easily fixed by winding the binding wire. Therefore, it has the advantage that it is easy to manufacture and can be manufactured at high speed.

However, since it basically does not have a braking winding, it is necessary to use a part of the field winding to provide a braking effect. Depending on the way the wires are connected when winding, it may not be possible to have any braking effect at all, or
In addition, when trying to increase the braking effect, there are drawbacks such as a decrease in the field winding utilization rate, so synchronous motors are rarely used for other than special purposes, and non-commutator motors Currently, it is hardly used.

The present invention was made in view of the above-mentioned circumstances, and its purpose is to take advantage of the advantages that it is easy to manufacture and to manufacture a high-speed product, while also having a large braking effect and a method for using a winding as a field winding. An object of the present invention is to provide a cylindrical field pole rotating electrical machine suitable for a commutatorless motor device that can increase the utilization rate.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an axial sectional view of an iron core portion of a cylindrical field pole rotating electric machine having a field winding according to the present invention. In the figure, a rotor core 2 is fitted onto a rotating shaft 1, and field windings 3 are inserted into a number of axial grooves 2a provided on the outer periphery of the core 2.
And the axial coil end part is pinned 4,
4' is wound and fixed. Further, a stator core 6 is arranged around the rotor core 6 with a minute gap 5 in between, and the armature winding 7 is inserted into a large number of axial grooves 6a provided on the inner circumference of the core 6. It is stored.
Although not shown in the drawings, the provision of a stator core frame, a bearing, a bearing device, an exciter, a rotating rectifier, etc. in the case of a brushless excitation method is the same as in a normal synchronous machine.

Next, in the rotating electric machine having the above configuration, each coil of the field winding 3 housed in the core groove is wound in a hexagonal shape using an electric wire with a rectangular cross section, or an insulated electric wire with a small circular cross section is used. It is manufactured as a random winding winding, and is housed as a two-layer wave winding or a lap winding, and as a whole, it consists of three windings with a phase difference of 120 degrees in electrical angle from each other, as shown in Figure 2. Groups a, b, and c are connected in series, and the neutral points are tied together in the same way as the star-shaped connection of a normal three-phase AC winding, and the output terminals of winding groups b and c are connected in series. The point where they are connected so as to short-circuit them is one terminal of the field winding, and the output side terminal of winding group a is connected internally so as to be the other terminal of the field winding. Here, the winding group a and the winding groups b and c are not exactly the same, but have the following differences. In other words, the number of conductors connected in series between the terminals of each group (twice the number of turns) is set so that when group a is 100, groups b and c are twice as many as 200, and from each terminal The cross-sectional area of the conductor is b, c when group a is set as 100.
The group is composed of 1/2 of 50.

This relationship will be explained in more detail with reference to FIGS. 3a and 3b. FIG. 3a shows a cross-section inside the groove of a coil belonging to group a, and FIG. 3b shows a cross-section inside the groove of a coil belonging to groups b and c. In the figure, mutually insulated electric wires 3a are ground-insulated with an insulator 3b, housed in two layers in a core groove 2c of a rotor core 2, and fixed with a wedge 3c.
As can be seen by comparing Figure 3 a and b, a
The number of conductors in groups B and C is 8, while the number of conductors in groups B and C is 8, and the cross section of those in groups B and C is half that of group A.

As is clear from FIG. 2, the field winding having the above configuration is one example of use as a synchronous machine for a normal induction synchronous motor. This is the same as connecting two terminals of a three-phase star connection. It is well known that in such a connection, the short-circuited winding groups b and c have a damping effect on the horizontal axis component, and that the a winding group has a damping effect on the direct axis component in a circuit via an excitation power source. ing. However, in the above-mentioned conventional induction synchronous motor, a resistor must be connected to the field winding side as a wound conductor motor when starting, so the winding groups a, b, and c generate a balanced three-phase voltage. Therefore, the number and cross-sectional view of each series-connected conductor must be the same. Therefore, when used as the field winding of a synchronous machine as shown in Figure 2, the current flowing through the a winding group is b,
Since the current is divided by half into each C winding, the current density is halved if the cross-sectional area is the same, resulting in unbalanced heat distribution on the rotor surface. Also, the magnetomotive force created by the windings is 1/2 that of the a winding group,
Furthermore, since winding groups b and c have a phase difference of 120°, their combination is also 1/2 of that of winding group a, and the overall result is that of winding group a alone, together with the magnetomotive force of winding group a. It will only be 3/2 times as much. In other words, the three sets of windings can collectively obtain only 3/2 times as much magnetomotive force as one set of windings, so the utilization rate of the windings is 1/2.

On the other hand, since this configuration is intended for use as a commutatorless motor, the field winding is constantly excited by direct current, so there is no need to generate a balanced three-phase voltage as a three-phase winding. winding group a and b and c
The number of series conductors in the winding groups does not have to be equal. Basically, the ratio may be arbitrary, but it is usually set to a:b (or c)=1:2 in view of the ease of distributing grooves on the rotor and connecting the windings. As a result, a,
The magnetomotive forces created by winding groups b and c are all equal,
The resultant magnetomotive force is twice the magnetomotive force of one set, and
The utilization rate of the winding is 2/3, and it is possible to obtain a magnetomotive force that is 4/3 = 1.333 times that of the conventional one. Also, the cross-sectional area of each winding group is a:b(or c)=2:1
Therefore, the current density is the same and the heat distribution on the rotor surface is even and balanced.

In this way, in a cylindrical field pole rotating electric machine, the field winding 3 is housed as a two-layer coil in grooves evenly distributed around the circumference of the iron core, and these are arranged at an electrical angle from each other.
Three winding groups a, b, and c with a phase difference of 120° are connected in series, and the neutral points are connected so that the whole becomes a star shape, and the terminals of the first winding group a are connected in series. It is used as one terminal as the field winding 3, and the terminals of the second and third winding groups b and c are directly short-circuited internally, and then used as the other terminal of the field winding 3, and the above-mentioned The number of conductors connected in series between the terminals of the first winding group a is twice that of the second and third winding groups B and C, and A cylindrical field pole rotating electric machine characterized in that the conductor cross-sectional area of the second and third winding groups b and c is set to be half of the conductor cross-sectional area of the wire group a as viewed from the terminal.

Therefore, it is possible to obtain a field winding that increases the utilization rate of the winding so that it can obtain a sufficiently large magnetomotive force as an excitation winding while ensuring a sufficiently large braking effect, and this allows the overall motor to be made smaller. It is possible to achieve reduction in size and weight. In addition, since it is easier to manufacture and to fix the coil than the field winding of conventional saliency pole or turbo type motors, relatively high speed machines can be easily manufactured at extremely low cost.

Note that the present invention is not limited to the above embodiments.

As mentioned above, the number of series conductors in the a winding group and the b and c winding groups need not be equal. Also,
The phase difference between the a, b, and c winding groups does not necessarily have to be 120°; it is simply the phase difference between the a winding group and b winding group, and the phase difference between the a winding group and c winding group. It suffices if they are equal.

To be more specific, for example, as shown in Figure 4, as a normal three-phase winding, the number of grooves for each pole and each phase is 3.1.
In a device with 9 poles, if the number of grooves in winding group a is 5, and each of winding groups b and c is 2, then the number of conductors in one groove in winding group a is x ,b
And when that of winding group c is set to 2x, the ratio of the number of series conductors is a: b (or c) = 5x: 4x = 5: 4, and the ratio of magnetomotive force is a: b (or c) 5x: 4x ×1/2 = 5:2 (1/2 is the current ratio). On the other hand, the phase is 5.5 grooves apart from the center of the a winding group and the center of the b winding group or c winding group, so there is a difference of 180°/9 grooves×5.5 grooves=110°. Then, the total magnetomotive force is the vector sum of the magnetomotive forces of each winding group, so when we examine the component of the magnetomotive force of each winding group in the direction of the a winding group, we find that it is due to the a winding...5x The b winding is due... ...4x x 1/2 x sin20° = 0.68x Due to c winding ...4x x 1/2 x sin20° = 0.68x The total is 6.36.

On the other hand, when configured as a normal three-phase winding,
Since the magnetomotive force per equivalent is 3x, the magnetomotive force is 6.36x ÷ 3 = 2.12 times that, and the total magnetomotive force is also 2.12 ÷ 1.5 = 1.4 times, increasing the utilization rate as an excitation winding. On the other hand, the effect as a damper winding is sufficiently large and the heat distribution on the iron core is uniform.

In addition, the total magnetomotive force has increased by 2.12 ÷ 2 = 1.06 times compared to the example described above.
This slight increase means an increase in the degree of freedom at the design stage, which is extremely advantageous when performing optimal design. Furthermore, here, the number of grooves is small for convenience of explanation, but since there are many grooves in an actual machine, it is possible to take any combination according to the convenience of the design.

On the other hand, in the explanation of the above embodiment, if the cross-sectional area of the coil belonging to the a winding group is twice the cross-sectional area of the coils belonging to the b and c winding groups, the conductor strands are Although all the coils are described as having different cross-sectional areas, as shown in Figure 3b, the number of conductors housed in half of the groove is an even number, and those belonging to winding group a are divided into winding groups b and c. Twice the number of strands belonging to the coil may be arranged in parallel at the connection portion of the coil end.

Furthermore, in a multi-pole machine that can configure multiple parallel circuits, after completing the internal series connection of each circuit as coils with the same cross-sectional area and the same number of series conductors for the a, b, and c winding groups, It is also possible to change the connection at the connection between poles so that the winding group has twice as many parallel circuits as the other winding groups B and C. Furthermore, it goes without saying that the invention can also be applied to synchronous motors and generators that do not self-start.

As explained above, according to the present invention, a non-commutator that can have a large braking effect and increase the utilization rate of the winding as a field winding while taking advantage of the fact that it is easy to manufacture and can be manufactured at high speed. A highly reliable cylindrical field pole rotating electric machine suitable for electric motor equipment can be provided.

[Brief explanation of drawings]

Fig. 1 is an axial sectional view showing the vicinity of the core of a cylindrical field pole rotating electric machine, Fig. 2 is a schematic diagram showing the internal connection of the field winding according to the present invention, and Figs. FIG. 4 is a sectional view showing the state of the field winding, and is an explanatory diagram showing the distribution and phase relationship of the field winding on the circumference of the iron core. DESCRIPTION OF SYMBOLS 1...Rotating shaft, 2...Field core, 2a...Field core groove, 3...Field winding, 3a...Field winding conductor, 3b...Insulation of field winding, 3c... ... Wedge for fixing the field winding, 4... Bind for fixing the coil end of the field winding, 5... Iron core gap, 6... Stator core, 7... Stator winding.

Claims (1)

[Claims] 1. In a cylindrical field pole rotating electric machine, the field winding is housed as a two-layer coil in grooves evenly distributed around the circumference of the iron core, and these are arranged with a phase difference of 120 degrees in electrical angle. Connect them in series to form three groups of windings with and the terminals of the second and third winding groups are directly short-circuited internally and used as another terminal of the field winding, and a conductor is connected in series between the terminals of the first winding group. The number of the second and third winding groups is set to be twice that of the second and third winding groups, and the cross-sectional area of the conductor seen from the terminal of the first winding group is set to be twice that of the second and third winding groups. A rotating electric machine with cylindrical field poles, characterized in that the magnetic field is reduced to half. 2 While maintaining the ratio of the conductor cross-sectional areas of the first group, second group, and third group to 2:1,
The phase difference between the first group and the third group is set to any value other than 120° in electrical angle, and the number of series conductors connected between the terminals of the second group and the third group is equal. The cylindrical field pole rotating electric machine according to claim 1, wherein the number of grooves belonging to each group is adjusted so that the ratio to the number of conductors is any value other than twice.