JP2000125511A - Cooler of dynamo-electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cope with high output and ripples in output by raising and adjusting the cooling capacity of a rotor. SOLUTION: A heat exchanger is constituted, being divided into a heat exchanger 12a for cooling of a rotor and a heat exchanger 12b for cooling a stator. In the case of stator, the calorific value is larger than that of the rotor, but the tolerable temperature can be any temperature as long as it is not higher than the heat resistance temperature of insulating material. In the case of the rotor, the calorific value is less than that of the stator, but it is better for the air temperature at the outlet of the heat exchanger to be as low as as possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling apparatus for a gas-cooled rotary electric machine having a large capacity.

[0002]

2. Description of the Related Art A rotor of a gas direct cooling type rotary electric machine has an axially formed coil slot in which a plurality of rotor windings or coils are arranged. These coil slots are arranged at intervals on the outer peripheral surface of the rotor main body on both sides of the magnetic pole portion of the rotor main body, and a plurality of coils constituting the same magnetic pole are arranged concentrically around the magnetic pole. These coils are formed by stacking multiple turns of coil conductors in the radial direction.
An insulating layer is provided between turns. When the coil is energized from the outside, an electromagnetic field required for each magnetic pole is generated. This coil is firmly fixed with a wedge inside the coil slot in the rotor so that the coil is not skipped in the radial direction of the coil by the strong centrifugal force due to the rotation of the rotor. It is fixed by a cylindrical retaining ring provided so as to be in contact with the part.

When electricity is supplied to the coil, Joule heat is generated in the coil conductor. A material having high heat resistance such as mica is used for the insulating layer of the coil.
A temperature rise of 0 degrees is the limit. Further, the thermal expansion of the coil conductor due to the temperature rise gives a large distortion to the coil and the rotor, which may cause rotational vibration.

Therefore, as described in US Pat. No. 5,652,469, a cooling gas sucked by a fan from the inside of the machine flows to a heat exchanger, and after heat exchange, is divided into a stator and a rotor to cool each part. Then, the cooling gas that has merged in the machine is sucked by the fan and returns to the heat exchanger again. In this cooling method, the cooling gas having a low temperature immediately after passing through the heat exchanger is directly guided to the stator and the rotor, so that the cooling efficiency is high.

[0005]

However, the above prior art has the following problems.

First, the cooling of the field coil of the rotor is more important than the stator in terms of output performance. That is, if the cooling of the field coil of the rotor is insufficient, the field current decreases due to the temperature rise and the magnetomotive force decreases, so that the output current from the stator significantly decreases. However, if the performance of the heat exchanger is directly improved to the cooling performance required for the field coil, the overall air temperature after the heat exchange decreases, but the cooling performance for the stator becomes more than necessary,
It is not preferable in terms of space and cost of the heat exchanger.

Secondly, no means for adjusting the cooling performance with respect to changes in output current, in other words, fluctuations in the amount of heat generated is taken into consideration.

A first object of the present invention is to provide a cooling device for a rotating electric machine that efficiently cools a rotor of the rotating electric machine.

A second object of the present invention is to provide a cooling device for a rotating electric machine having means for adjusting the cooling performance according to the output.

[0010]

A first object of the present invention is to provide a rotor, a stator for outputting electric power, a fan fixed to the rotor, and a cooling gas sucked from the fan to a heat exchanger. In a cooling device for a rotating electrical machine including a guiding duct and a duct for guiding a cooling gas from the heat exchanger to the stator and the rotor, this is achieved by separately providing the stator and the rotor heat exchanger. Is done.

The heat exchanger is achieved by exchanging heat with a cooling gas and a cooling liquid introduced from a cooling tower.

[0012] The second object is to provide a rotor, a stator for outputting electric power, a fan fixed to the rotor, a duct for guiding cooling gas sucked from the fan to a heat exchanger, and a heat exchanger. A cooling device for a rotating electrical machine including a duct for guiding a cooling gas from an exchanger to the stator and the rotor, by including a flow rate adjusting means for the cooling liquid for adjusting a heat exchange amount of the heat exchanger. Achieved.

[0013]

FIG. 1 is a conceptual diagram of a gas turbine generator. The gas turbine generator transmits the rotation output of the gas turbine motor 101 to the generator 102 via the rotating shaft 103. FIG. 2 shows a schematic structure of the air-cooled generator. FIG. 2 is a schematic cross-sectional structural view of a closed-type air-cooled generator having a heat exchanger and circulating air inside the generator.

The rotor 1 is rotatably supported by a bearing 3 in a stator 2. On the rotor 1, a plurality of coils 4 constituting the same magnetic pole are fixed concentrically around the magnetic pole. The centrifugal force acting on the coil 4 is firmly supported in the axial direction by coil slots formed at intervals on the outer peripheral surface of the rotor, and in the circumferential direction of the rotor end by the retaining ring 5.

A fan 6 is arranged between the retaining ring 5 and the bearing 3, and the air inside the machine is sucked by the rotation of the rotor 1, and the air is sent from the return duct 11 to the heat exchanger 12. The air whose temperature has been lowered by heat exchange is diverted to the stator duct 13 and the rotor duct 14.

The air from the stator duct 13 flows to the stator 2 and the space 10 on both sides of the stator 2 (the flow of air is indicated by an arrow 7). On the other hand, air from the rotor duct 14 flows into the space between the coil 4 at the end of the rotor 1 and the axis of the rotor 1 (arrow 8), and after cooling the coil 4, a gap between the rotor 1 and the stator 2 called an air gap 9 is formed. Is discharged. The air that has joined from the stator and the rotor is
And is returned to the return duct 11 again.

In this cooling system, the low-temperature air coming out of the heat exchanger 12 is heated by the stator 2 and the rotor 1 serving as heat-generating parts.
Cooling efficiency is high because it is led directly to On the other hand, it is advantageous that the coil 4 is cooled as much as possible in terms of output. That is, if the cooling of the field coil is insufficient, the field current decreases due to the temperature rise and the magnetomotive force decreases, so that the output current from the stator significantly decreases. In other words, the cooling of the field coil is more important than the stator in terms of output performance.

However, if the performance of the heat exchanger 12 is directly improved to the cooling performance required for the coil 4, the air temperature after the heat exchange certainly drops, but the cooling performance for the stator 2 becomes more than necessary. However, it is not preferable in terms of space and cost of the heat exchanger.

Therefore, as shown in FIG. 3, the heat exchanger 12 is divided into a rotor cooling heat exchanger 12a and a stator cooling heat exchanger 12b. That is, an appropriate heat exchanger is determined from the calorific value of each of the rotor and the stator and the necessary heat exchanger outlet air temperature. In the case of the stator, the calorific value is larger than that of the rotor, but the allowable temperature may be lower than the heat resistant temperature of the insulating material. On the other hand, in the case of the rotor, the calorific value is smaller than that of the stator, but the air temperature at the outlet of the heat exchanger is preferably as low as possible.

In this cooling system, the heat generated inside the machine is collected in the return duct 11 via the cooling air, so that the heat is separately diverted to the rotor cooling heat exchanger 12a and the stator cooling heat exchanger 12b. Since the stator generates more heat than the rotor, the air volume needs to be distributed more to the stator cooling heat exchanger 12b. The heat exchanger 12 for cooling the rotor
Although the distribution of the air volume to a must be reduced, it is performed by means such as increasing the flow rate of the cooling liquid in the heat exchanger tube or supplying a low liquid temperature in order to lower the outlet air temperature as much as possible. In addition,
In the case of the rotating electric machine of the present invention, the operation is performed with the rotation speed of the rotor 1, in other words, the rotation speed of the fan 6, constant, so that the air volume becomes substantially constant.
The air volume required for the heat exchanger 2a and the stator cooling heat exchanger 12b may be set in advance by means such as pressure loss adjustment.

As the coolant in the heat exchanger, seawater is used when the rotating electric machine of the present invention is installed in a coastal area. That is, as shown in FIG. 4, the seawater 15 is sent into the pipe of the heat exchanger 12 by the pump 16 and returns to the seawater 15 again after the heat exchange. Seawater is inexhaustible and is preferable in that it is inexpensive. However, since the water temperature fluctuates depending on the climate, for example, in summer when the power load increases, the seawater temperature also increases, so that the performance of the heat exchanger deteriorates. There is a problem that it is not possible to cope with an increase in power load due to insufficient cooling of the power supply.

Therefore, a cooling tower 17 is separately provided as shown in FIG. By doing so, it becomes possible to stabilize the cooling performance of the heat exchanger and to cope with fluctuations in the power load without being affected by fluctuations in the seawater temperature. It is also effective when a rotary electric machine is installed and operated at a location other than the coastal area. Although not shown, seawater may be supplied to the cooling liquid in the pipe of the heat exchanger for cooling the stator 12b, and the cooling tower 17 may be supplied to the cooling liquid in the pipe of the heat exchanger for cooling the rotor 12a.

On the other hand, the output of the rotating electric machine is continuously 100%
Rather, it is usually used below. However, as described above, there is a case where the operation is temporarily performed at an output of 100% or more. In this case, naturally, it is necessary to temporarily increase the cooling performance of the stator and the rotor. Therefore, as shown in FIG. 6, the seawater 15 and the cooling tower 17 are used together as the cooling liquid in the pipe of the heat exchanger 12. That is, during normal operation, only the seawater 15 is used and the cooling tower 17 is not used.
On the other hand, when a load of 100% is required, the flow rate control valve 18 is actuated by sensing the signal or the temperature rise of the rotor and the stator, the coolant is supplied from the cooling tower 17, and the heat exchanger 12 is operated. To temporarily increase the cooling performance.

By adopting such a configuration, a rotor capable of coping with load variations can be obtained by simply adding a cooling tower 17 and a flow control valve 18 to a conventional cooling liquid supply pipe from seawater 15.
The cooling device for the stator can be realized at a reduced cost.

[0025]

As described above, according to the present invention, a cooling device for a rotating electric machine that efficiently cools the rotor of the rotating electric machine can be obtained. Further, a cooling device for a rotating electric machine having a means for adjusting the cooling performance according to the output can be obtained at low cost.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating the configuration of a gas turbine generator according to the present invention.

FIG. 2 is a diagram illustrating a conventional cooling device for a rotating electric machine.

FIG. 3 is an explanatory diagram showing one embodiment of the present invention.

FIG. 4 is a system diagram of a conventional cooling device for a rotating electric machine.

FIG. 5 is a system diagram showing an embodiment of the present invention.

FIG. 6 is a system diagram showing another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... rotor, 2 ... stator, 3 ... bearing, 4 ... coil, 5
... Retaining ring, 6 ... Fan, 7,8 ... Arrow, 9 ...
Air gap, 10 ... space, 11 ... return duct, 12 ...
Heat exchanger, 12a: Heat exchanger for cooling the rotor, 12b: Heat exchanger for cooling the stator, 13: Stator duct, 14:
Rotor duct, 15 seawater, 16 pump, 17 cooling tower, 18 flow control valve, 101 gas turbine motor,
102: generator, 103: rotating shaft.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigekazu Kieda 502, Kandate-cho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. (72) Inventor Akiyoshi Iida 502, Kandachi-cho, Tsuchiura-shi, Ibaraki F-term in Machinery Research Laboratory, Hitachi, Ltd. RR33 RR37 RR42 RR43 RR46 RR53 RR67 RR70 RR73

Claims (1)

[Claims] 1. A rotor, a stator for outputting electric power, a fan fixed to the rotor, a duct for guiding cooling gas sucked from the fan to a heat exchanger, and the stator from the heat exchanger. What is claimed is: 1. A cooling apparatus for a rotating electric machine, comprising: a stator and a duct for guiding a cooling gas to the rotor, wherein the stator and the rotor heat exchangers are separately provided.