JPS607895B2 - Stator of rotating electric machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stator of a rotating electrical machine such as a turbine generator, and particularly to cooling of an end portion of the core thereof.

In general, a stator core of a rotating electric machine is constructed by laminating thin iron plates, and these are fixed to a stator frame by a stator iron holding plate. By the way, leakage magnetic flux due to field winding magnetomotive force and armature winding supermagnetic force exists in a complicated manner near the end of the stator core where the stator core holding plate is arranged. For this reason, eddy current loss occurs at the ends of the stator core, causing local overheating. In particular, at positions where the current phase of the coils inserted into the slots of the stator iron ○ changes, magnetic fluxes due to currents with different phases coexist, so leakage magnetic flux increases and harmonics are included in the magnetic flux waveform. As a result, hysteresis loss and eddy current loss occurring within the iron core are increasing, and temperature rise is also increasing. FIG. 1 shows the relationship between the circumferential position at which the current phase of the stator coil changes and the temperature rise in the circumferential direction at the end of the stator core.

A stator core 1 is provided with a slot 2, into which a coil 3 forming a stator winding is inserted.

A three-phase alternating current flows through the coil 3 inserted into this slot 2. In general, turbine generators are formed with two layers, upper and lower, and short-pitch winding is adopted, so the upper layer coil and the lower layer There are slots in which the current phases flowing through the coils are different, and these slots are distributed at regular intervals in the circumferential direction. By the way, the solid line A in Figure 1 is
This shows the temperature rise at the end of the stator core.
, et al., and t3, the temperature rise is larger than the other portions.

This is the circumferential direction t. , t2, etc., the phase of the current in the slot changes, magnetic fluxes due to currents with different phases coexist, and the loss generated in the core increases as described above. That is, in the case of circumferential position 5, U-phase and V-phase currents are flowing in the left slot, whereas V-phase current is flowing in both the upper and lower layers in the right slot.

It can be seen that the temperature rise at the end of the stator core increases due to the difference in the phase of the current in the slots. Recently, the temperature rise at the end of the stator core has almost reached its limit due to reductions in machine dimensions and increases in capacity.

Therefore, in order to increase the cooling effect of these parts, a method is being adopted in which the stator core press plate 4 is provided with a cooling medium passage through which a cooling medium, such as pure water or oil, is passed for direct cooling. Figure 2 shows the direct cooling method for the stator core holding plate.

This figure shows the end of the stator iron ○ viewed diagonally from above. A stator core 1 is provided with a slot 2, into which a coil 3 forming a stator winding is inserted. A stator core holding plate 4 is disposed at the end of the stator core 1 in the vertical direction, and a main supply pipe 6 is attached to the outer periphery of the stator core 1, which is fixed by a stator core clamping plate 5. A main discharge pipe 7 is arranged extending in the circumferential direction. The cooling medium reaches the stator core holding plate 4 through a suction pipe 8 connected to the main supply pipe 6, and flows through radial cooling medium passages (not shown) provided in the stator core holding plate 4. It returns via the stator core holding plate tip 4a.

Next, this cooling medium passes through the connecting pipe 10, reaches the adjacent stator core holding plate 4, passes sequentially through the cooling medium passages in the stator core holding plates 4 connected in series, and finally reaches the discharge pipe 9.
and reaches the main discharge pipe 7. Figure 3 shows the current phase (V
This figure shows the relationship between the W phase and W phase.

In the conventional system, a coil group a has only the V phase flowing through the coolant passage, and a coil group b has the V phase and W phase flowing through the coolant passage. The entire circumferential direction was divided into a plurality of parts regardless of changes in the internal phase current. For this reason, t
In order to eliminate the temperature rise in the circumferential direction as shown in Figure 1, it is necessary to increase the overall cooling flow rate. This was extremely uneconomical as it required conversion.

The purpose of the present invention is to provide a stator for a rotating electrical machine that can correct the temperature rise at the end of the stator core and economically eliminate the maximum point of temperature rise distributed in the circumferential direction. It is in.

To achieve this objective, the present invention focuses on the fact that the maximum temperature rise at the end of the stator core occurs at a point where the in-slot phase current phase is changing, and the stator core at this portion The flow resistance of the cooling medium passage provided in the holding plate is
The flow resistance of the cooling medium passages is made smaller than that of other parts of the cooling medium passage.

Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 4 shows an embodiment of the present invention.

The suction pipe and the discharge pipe connected to the main supply pipe 6 and the main discharge pipe 7 are connected to the suction pipe 8b,
A discharge pipe 9b is provided, and other parts are provided with a separate suction pipe 8a,
A flow path is formed by the discharge pipe 9a and the connecting pipe 1. FIG. 5 shows the relationship between the current phase of the cooling medium passage system and the coil in the slot according to the present invention. The current phases of the coils in the slots are coil group a with only V phase flowing, and coil group b with V phase and W phase flowing.
, and are divided into coil groups c containing only the W phase.

The suction pipe 8b and the discharge pipe 9b are provided in a portion where the phase current in the slot changes, and in other parts, a cooling medium passage is formed by the suction pipe 8a, the discharge pipe 9a, and the connecting pipe 1. Therefore, the portion located in the circumferential direction shown in FIG. Compared to the cooling medium passage formed by the pipe 8a, the discharge pipe 9a, etc., the flow path length is shorter, that is, the flow resistance is smaller, so the amount of cooling medium increases and the cooling effect in this part increases.

Therefore, the local temperature rise that occurs at the end of the stator core can be reduced by
This problem can be solved without significantly increasing the flow path dimensions or circulation pump capacity. In this case, the suction pipe 8b, the discharge pipe 9b, etc. may be made larger than the suction pipe 8a, the discharge pipe 9a, etc. in order to reduce the flow resistance of the coolant passage. Therefore, with this configuration, it is possible to eliminate the local temperature rise that occurs at the end of the stator core, as shown by the broken line B in FIG. As described above, according to the present invention, the maximum point of temperature rise at the end of the stator core can be easily and economically eliminated.

[Brief explanation of drawings]

Figure 1 is a characteristic diagram showing the relationship between the directional position of the stator coil while the current phase changes and the temperature rise along the circumferential direction of the stator core end, and Figure 2 is a characteristic diagram of the conventional stator core holding plate. FIG. 3 is an explanatory diagram showing the relationship between the flow path system of the cooling device shown in FIG. 2 and the coil current in the slot, and FIG. 4 is a perspective view showing the cooling device according to an embodiment of the present invention. FIG. 5 is a perspective view showing the cooling device for the D holding plate, and is an explanatory diagram showing the relationship between the flow path system of the cooling device shown in FIG. 4 and the coil current in the slot. 1... Stator core, 3... Stator coil, 4...
・Stator core holding plate, 6... Main supply pipe, 7...
...Main outlet pipe, 8a, 8b...Suction pipe, 9a,
9b...Discharge pipe. Younger brother Figure 2 Figure 2 Figure 4 Figure 5

Claims (1)

[Claims] 1. A stator core having a slot, a stator winding housed in the slot of the stator core and through which a multiphase alternating current flows, and a stator winding disposed at an axial end of the stator core. A stator core holding plate that is tightened and fixed and has a cooling medium passage through which a cooling medium flows; and a main discharge pipe that discharges the cooling medium from the cooling medium passage of the stator core holding plate, and the cooling medium passage is arranged radially between the slots in the stator core holding plate. In a stator of a rotating electric machine, in which a cooling medium is allowed to flow through the cooling medium passage to cool an end of the stator core, a slot is located at a position where the current phase of each coil constituting the stator winding changes. 1. A stator for a rotating electric machine, characterized in that the flow resistance of a coolant passage disposed between the two slots is smaller than that of a coolant passage disposed between other slots.