JPH0125312B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a superconducting generator, and more particularly to a superconducting generator having a laminated stator core.

A superconducting generator consists of a superconducting rotor, stator, etc., and conventional examples are shown in Figures 1 and 2.
As shown in the figure. The superconducting rotor 1 includes a superconducting field winding 2, a torque tube 3 that supports the superconducting field winding 2 from the inner diameter side, a damper 4 that protects the superconducting field winding 2 from transient magnetic fields on the stator side, and the like. Both shaft ends are supported by bearings (not shown). On the other hand, the stator is composed of an armature winding 5 and a stator core 6, and the armature winding 5 is connected to a cylindrical support 7 made of an insulator from the inner diameter side and an insulator 8 from the outer diameter side. It has been well supported. The stator core 6 usually has a thickness of 0.35~
0.5mm silicon steel plates are laminated in the axial direction.
It is formed by tightening and fixing it with an iron core holder 10, bolts 9, etc.

By the way, on the superconducting rotor 1 side of the superconducting generator configured in this way, a high magnetic field is generated by the superconducting field winding 2, and magnetic materials with problems of magnetic saturation cannot be used for the structure, so all non-magnetic materials are used. It has a so-called air-core structure made of wood. When viewed in an arbitrary axial cross section, the magnetic flux φ generated by the superconducting field winding 2 interlinks with the armature winding 5 disposed in a predetermined gap and induces a voltage in the stator. A closed circuit (see FIG. 2) as shown by the dotted line in the figure is formed between the stator core 6 and the superconducting rotor 1 through the core 6.

In this way, the superconducting rotor 1 has an air-core structure, so unlike a conventional generator with a so-called iron-core rotor that uses magnetic materials for its structure, the direction of the field current changes by 90 degrees, especially at the shaft end. Therefore, the magnetomotive force is small at the shaft end, and only interlinks with the superconducting field winding 2 itself and the armature winding 5, and does not enter the stator core 6 as shown by the magnetic flux φ indicated by the arrow in the figure. Magnetic flux increases. As a result, the magnetic flux φ incident on the stator core 6 is:
As shown in the distribution curve of the magnetic flux incident on the stator core according to the axial position in FIG. It tends to be a mountain-shaped distribution, with the maximum at the center and decreasing toward the ends of the shaft, and this has been confirmed experimentally.

Therefore, the magnetic flux density of the stator core 6 of the conventional structure is high only in the central part in the axial direction, and therefore the core loss in the central part increases and the temperature rises significantly. In addition, since the magnetic flux density decreases toward the shaft end of the stator core 6, the utilization rate of the magnetic flux of the stator core 6 decreases, which increases the weight of the stator core 6 and, in turn, increases the weight of the superconducting generator. There were flaws.

The present invention has been made in view of the above points,
The objective is to provide a superconducting generator having a stator core with reduced weight and iron loss.

That is, the present invention is characterized in that the stator core is formed of an iron core whose height in the radial direction increases toward the center in the axial direction.

The present invention will be explained below based on the illustrated embodiments. FIG. 4 shows an embodiment of the present invention. Note that parts that are the same as those in the conventional model are given the same reference numerals, and therefore their explanations will be omitted. In this embodiment, the stator core 6
was formed of iron cores 6, 6b, and 6a whose height in the radial direction increases from the ends toward the center. In other words, the stator core 6 has outer diameters 6a, 6b, and 6 whose outer diameters become smaller from the center to the end in the axial direction.
It was formed with a three-stage iron core. By doing this, the magnetic circuit cross section becomes larger toward the axial center of the stator core 6, allowing the magnetic flux to pass through it more easily, and the magnetic flux density distribution at the center can be relaxed. Since the magnetic flux density distribution is relaxed, iron loss is reduced and temperature rise is reduced. Further, since the radial dimension of the stator core 6 becomes smaller at the end where the magnetic flux density is lower, the utilization rate of the magnetic flux of the stator core 6 increases, and the weight of the stator core decreases. Furthermore, by changing the height of the core 6, the magnetic flux density in the axial direction of the core 6 can be made uniform, so the temperature distribution due to iron loss in the core 6 is also uniform, reducing the difference in thermal expansion and friction between the laminated cores. This will not damage the insulating varnish that is generally applied to the surface of the iron plates for the purpose of insulating them.

In this way, by increasing the radial height toward the axial center of the stator core 6,
A stator structure with high resistance to electromagnetic vibrations can be obtained. That is, generally superconducting rotor 1
The electromagnetic force generated by the interaction between the magnetic flux from the superconducting rotor 1 and the current in the armature winding 5 is larger as the magnetic flux of the superconducting rotor 1 approaches the center in the axial direction, so the electromagnetic force is also largest at the center in the axial direction. . However, as described above, since the height of the stator core 6 in the radial direction is increased toward the center in the axial direction, the stator core 6a closer to the center has greater rigidity against electromagnetic force.

Furthermore, when the armature winding 5 is a skew winding as in the present invention, the magnetic flux distribution due to the electromagnetic force current is similar to the magnetic flux distribution due to the superconducting rotor 1 described above, as described below. However, since the maximum mountain-shaped distribution occurs at the center in the axial direction, the effect of this embodiment is even more effective. As shown in FIG. 5, which is an expanded view of one phase of the skew-wound armature winding 5, the skew-wound armature winding 5 has coils 11a and 1 that constitute the armature winding 5.
The coil 1b is arranged diagonally with respect to the axial position, and the coil 11a on the stator core 6 side and the coil 11b on the superconducting rotor 1 side are twisted in opposite directions to form a turn. Since the current flows in the direction indicated by the arrow in the figure, the magnetic flux φa generated by this passes through the rhombic part 12 including the central part in the axial direction, and as a result of mutual cancellation at the end part 13, the magnetic flux due to the armature current As shown in the magnetic flux distribution curve according to the axial position in Figure 6, where the vertical axis is the magnetic flux distribution φa and the horizontal axis is the axial position, the distribution is maximum at the center in the axial direction, and reaches the end. The smaller the distribution becomes, the more it becomes a mountain-shaped distribution. Therefore, the closer to the center of the stator core 6 in the axial direction, the more the incident magnetic flux φa becomes.

Another embodiment of the invention is shown in FIG. In this embodiment, the height of the stator core 6 in the radial direction increases continuously from the ends toward the center. In other words, the stator core 6 is formed of an iron core 6a whose inner diameter is constant from the axial center part to a predetermined axial length, and an iron core 6b whose inner diameter is continuously increased from this point toward the end. did. By doing so, the following effects can be achieved. End core 6b
Since the inner diameter of the armature winding 5 increases continuously, the end of the armature winding 5 can be lifted in the outer diameter direction as shown in the figure, making it possible to connect the electrical and cooling systems to adjacent coils, etc. The work space required for electrical work will increase, making electrical work easier. Further, the required insulation distance between the stator core 6 and superconducting rotor 1 at ground potential and the armature winding 5 at high potential can be easily secured. Furthermore, since the inner diameter of the core 6b at the end of the stator core 6 increases continuously, the electric field concentration on the axial end of the stator core 6 can be alleviated.

FIG. 8 shows yet another embodiment of the invention. In this embodiment, the stator core 6 has cores 6d and 6 whose radial height increases from the end toward the center.
c, 6b and 6a. In other words, stator cores 6a, 6b, 6c, and 6d have an inner diameter that increases from the center to the end in the axial direction.
The inner diameter of only 6d of these cores is made to continuously increase toward the end. The axial length Lc of the stator core 6 thus formed was made larger than the axial length La of the armature winding 5 and the effective axial length Lf of the superconducting rotor 1. By doing so, as in the case of each of the above-described embodiments, the magnetic flux becomes easier to pass toward the center of the stator core 6 in the axial direction, and such effects can be achieved. In other words, the axial length of the stator core 6
Since Lc is larger than the axial length La of the armature winding 5 and the axial effective length Lf of the superconducting rotor 1, all of the magnetic flux generated in the armature winding 5 and the superconducting rotor 1 is transferred to the stator core. 6. Therefore, the magnetic flux incident at right angles to the stacking direction of the stator core 6d at the end near the core holder 10 (due to the circumferential current component generated at the ends of the armature winding 5 and the superconducting rotor 1) is transmitted to the stator core 6d. 6d are laminated, so that the current flows in the radial direction, thereby preventing eddy current loss at the axial ends of the stator core 6, and thereby preventing local heating.

In each of the above-mentioned embodiments, the radial height of the stator core is stepped or continuous from the end to the center in order to allow the magnetic flux to pass most easily through the axial center of the stator core. I tried to make it bigger. In this way, it is not only possible to change the shape symmetrically from the end portions to the center portion, but also to change it asymmetrically. Needless to say, even in this case, the same effects as in the above-mentioned embodiment can be obtained.

As described above, in the present invention, the stator core is formed of an iron core whose height in the radial direction increases toward the central part in the axial direction, so that the magnetic flux is most easily passed through the central part in the axial direction. The magnetic flux distribution of is relaxed,
The utilization factor for magnetic flux is increased and the weight and iron loss are reduced, making it possible to obtain a superconducting generator having a stator core with reduced weight and iron loss.

[Brief explanation of drawings]

Figure 1 is a longitudinal side view of a conventional superconducting generator, Figure 2 is a sectional view taken along line A-A in Figure 1, and Figure 3 is the axial position and core of the stator core of a conventional superconducting generator. FIG. 4 is a longitudinal sectional side view of an embodiment of the superconducting generator of the present invention.
FIG. 5 is an explanatory diagram explaining the effect of FIG. 4, FIG. 6 is a characteristic diagram showing the relationship between the axial position of the stator core of the superconducting generator of the present invention and the magnetic flux distribution due to the armature current, and FIG. The figure is a longitudinal sectional side view of another embodiment of the superconducting generator of the invention, and FIG. 8 is a longitudinal sectional side view of still another embodiment of the superconducting generator of the invention. 1...Superconducting rotor, 2...Superconducting field winding, 5...
Armature winding, 6, 6a, 6b, 6c, 6d... stator core.

Claims (1)

[Claims] 1. A superconducting rotor equipped with a superconducting field winding;
A superconducting power generator consisting of a skew-wound armature winding arranged on this superconducting rotor with a predetermined gap in between, and a stator core arranged around the outer periphery of this armature winding with an insulator in between. 1. A superconducting power generator, characterized in that the stator core is formed of a core whose height in the radial direction increases toward the center in the axial direction. 2. A superconducting rotor equipped with superconducting field windings,
A superconducting power generator consisting of a skew-wound armature winding arranged on this superconducting rotor with a predetermined gap in between, and a stator core arranged around the outer periphery of this armature winding with an insulator in between. In the machine, the stator core is formed of a core whose radial height increases toward the center in the axial direction, and the axial length thereof is larger than the axial length of the superconducting rotor and armature winding. A superconducting generator characterized by: