A dual shaft excited motor hybrid ventilation cooling system

Abstract

This invention provides a hybrid ventilation and cooling system for a dual-shaft excitation motor. The system includes a stator core, a stator radial ventilation groove, an annular circumferential air gap baffle, a stepped cross-section secondary slot ventilation duct, a double radial straight air duct, an alternating radial air duct, and an air gap. A stator radial ventilation groove is formed between two stacked segments of the stator core. An annular circumferential air gap baffle is installed within the radial ventilation groove in the high-temperature region of the stator winding. On the side with the circumferential air gap baffle, the corresponding rotor secondary slot has a stepped cross-section secondary slot ventilation duct. The radial ventilation groove is a double radial straight air duct, and the radial ventilation groove is an alternating radial air duct. The circumferential air gap baffle allows hydrogen gas from the double radial straight air duct to directly enter the stator radial ventilation groove. The stepped cross-section secondary slot ventilation duct and the double radial straight air duct increase the uniformity of airflow distribution, reduce wind resistance, and lower rotor temperature; the rectangular cross-section secondary slot ventilation duct and the alternating radial air duct also make the axial temperature distribution of the rotor more uniform.

Description

Technical Field

[0001] This invention relates to the field of motor rotor cooling technology, and in particular to a hybrid ventilation cooling system for a dual-shaft excitation motor. Background Technology

[0002] As the installed capacity of large generators continues to increase, their electromagnetic and thermal loads also increase, resulting in high winding and core temperatures that severely impact the lifespan and safety of the generator-condenser. Therefore, to reduce the temperature of the stator and rotor windings and core, corresponding cooling systems for large generators have been proposed, such as water-hydrogen-hydrogen cooling systems. The principle is that the stator windings consist of solid and hollow strands; water flows through the hollow strands, while hydrogen is filled inside the generator-condenser. To further reduce the rotor winding temperature, secondary slots are created in the rotor core, and radial ventilation grooves are opened inside the rotor windings to allow hydrogen to pass through, thus lowering the rotor winding temperature and reducing the risk of overheating.

[0003] However, because hydrogen cools the rotor windings through the rotor radial ventilation channels, the flow of the hydrogen exiting the channels is affected by rotation, centrifugal force, and turbulent conditions. Therefore, its entry into the stator radial ventilation channels is not linear or regular. Furthermore, water flowing axially through one end of the stator winding nose absorbs heat and exits from the other end. Throughout this process, the water temperature continuously rises until it reaches the outlet. Consequently, the stator winding temperature is highest near the water outlet, resulting in an uneven axial temperature distribution. This can easily cause thermal stress, leading to bending of the hollow strands, insulation aging, and potentially serious accidents. Summary of the Invention

[0004] The embodiments of the present invention provide a hybrid ventilation and cooling system for a dual-shaft excitation motor to effectively reduce the stator and rotor temperatures of the generator and ensure the safe and reliable operation of a large-capacity generator.

[0005] To achieve the above objectives, the present invention adopts the following technical solution.

[0006] A hybrid ventilation and cooling system for a dual-shaft excitation motor includes:

[0007] Stator core (1), stator radial ventilation groove (2), stepped cross-section secondary slot ventilation duct (3), double radial straight air duct (4), rectangular cross-section secondary slot ventilation duct (5), alternating radial air duct (6), air gap (7) and annular circumferential air gap baffle (8);

[0008] The annular circumferential air gap baffle (8) is installed in the stator radial ventilation groove (2). The thickness of the annular circumferential air gap baffle (8) is 1 / 4 of the width of the ventilation groove, and the width is 1 / 2 of the length of the air gap. The annular circumferential air gap baffle (8) is set in the radial ventilation groove of the stator high temperature zone. The number of the annular circumferential air gap baffle (8) is 1 / 2 of the number of stator radial ventilation grooves.

[0009] The stator radial ventilation groove (2) is located between two adjacent stator core (1) stack segments, and the air gap (7) is located between the stator and the rotor;

[0010] The stepped cross-section auxiliary slot ventilation duct (3) is located at the corresponding position of the high temperature zone of the stator. The inlet of the stepped cross-section auxiliary slot ventilation duct (3) is stepped, that is, the area near the shaft is small and the area near the bottom of the slot is large. The stepped cross-sectional area remains unchanged from the end of the rotor to the center of the rotor.

[0011] The dual radial straight air duct (4) consists of two long rectangular ventilation ducts inside the rotor winding, located at the corresponding position in the high temperature zone of the stator. The bottom of the dual radial straight air duct (4) is connected to the stepped cross-section secondary slot (3), and the upper part of the dual radial straight air duct (4) is connected to the slot wedge ventilation duct.

[0012] The rectangular cross-section auxiliary slot ventilation duct (5) is located at the corresponding position in the low temperature zone of the stator, and the inlet of the rectangular cross-section auxiliary slot ventilation duct (5) is rectangular in shape. The rectangular cross-sectional area remains unchanged from the rotor end to the rotor center.

[0013] The alternating radial air duct (6) is located at the corresponding position of the stator low temperature zone. The bottom of the alternating radial air duct (6) is connected to the rectangular cross-section sub-slot (5). The upper part of the alternating radial air duct (6) is connected to the slot wedge ventilation duct (6-3). The alternating radial air duct (6) is formed by alternating arrangement of single radial straight air duct (6-2) and double radial straight air duct (6-1).

[0014] Preferably, the annular circumferential air gap partition (8) is made of thermally conductive, non-conductive and non-magnetic material and is welded onto the stator core (1) stack segment.

[0015] Preferably, the number of steps in the stepped shape is at least 1.

[0016] Preferably, the minimum number of single radial straight air ducts (6-2) and double radial straight air ducts (6-1) in the alternating radial air ducts (6) is 2.

[0017] Preferably, the radial heights of the single radial straight air duct (6-2) and the double radial straight air duct (6-1) are different, and their circumferential widths are different.

[0018] As can be seen from the technical solutions provided by the embodiments of the present invention above, the embodiments of the present invention provide a hybrid ventilation and cooling system for a dual-shaft excitation motor, which ensures the hydrogen flow rate in the stator radial ventilation groove, cools the stator winding, and makes the stator winding temperature as uniform as possible along the axial direction; at the same time, it improves the uniformity of flow distribution in the rotor radial ventilation groove, reduces the axial thermal imbalance of the rotor winding, and ultimately reduces the stator and rotor temperatures of the generator, ensuring the safe and reliable operation of a large-capacity generator.

[0019] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of the invention. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A schematic diagram of the axial-radial section of a ventilation and cooling system for a dual-shaft excitation motor provided in an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of a circumferential air gap baffle for a ventilation and cooling system of a dual-shaft excitation motor provided in an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of a stepped cross-section secondary groove and a double radial straight air duct in a ventilation and cooling system for a dual-shaft excitation motor, provided in an embodiment of the present invention.

[0024] Figure 4 This is a circumferential-radial schematic diagram of a rectangular cross-section secondary slot and alternating radial air duct of a dual-shaft excitation motor ventilation and cooling system provided in an embodiment of the present invention. Detailed Implementation

[0025] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0026] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or couplings. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.

[0027] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0028] To facilitate understanding of the embodiments of the present invention, the following will provide further explanation and description with reference to the accompanying drawings and several specific embodiments. These embodiments do not constitute a limitation on the embodiments of the present invention.

[0029] The structure of a ventilation and cooling system for a dual-shaft excitation motor provided in this embodiment of the invention is as follows: Figure 1 As shown, the structure includes: stator core 1, stator radial ventilation groove 2, stepped cross-section secondary slot ventilation duct 3, double radial straight air duct 4, rectangular cross-section secondary slot ventilation duct 5, alternating radial air duct 6, air gap 7, and annular circumferential air gap baffle 8.

[0030] A schematic diagram of the circumferential air gap baffle of a ventilation and cooling system for a dual-shaft excitation motor provided in this embodiment of the invention is shown below. Figure 2 As shown. A circular circumferential air gap baffle 8 is installed within the stator radial ventilation groove 2, and the thickness of the circular circumferential air gap baffle 8 is 1 / 4 of the width of the ventilation groove, and its width is 1 / 2 of the air gap length. The circular circumferential air gap baffle 8 is located within the radial ventilation groove in the high-temperature zone of the stator, and the number of circular circumferential air gap baffles 8 is 1 / 2 of the number of stator radial ventilation grooves.

[0031] The stator radial ventilation groove 2 is located between two adjacent stator core stack segments 1, and the air gap 7 is located between the stator and the rotor.

[0032] A schematic diagram of the stepped cross-section secondary groove and the double radial straight air duct of the ventilation and cooling system for a dual-shaft excitation motor provided in this embodiment of the invention is shown below. Figure 3 As shown. The stepped cross-section auxiliary slot ventilation duct 3 is located at the corresponding position in the high temperature zone of the stator. The inlet of the stepped cross-section auxiliary slot ventilation duct 3 is stepped, that is, the area is small near the rotating shaft and large near the bottom of the slot; the stepped cross-sectional area remains unchanged from the rotor end to the rotor center.

[0033] The dual radial straight air duct 4 consists of two long rectangular ventilation ducts inside the rotor winding, located at the corresponding position in the high temperature zone of the stator. The bottom of the dual radial straight air duct 4 is connected to the stepped cross-section secondary slot 3, and the top is connected to the slot wedge ventilation duct.

[0034] A rectangular cross-section secondary slot and alternating radial air duct circumferential-radial schematic diagram of a ventilation and cooling system for a dual-shaft excitation motor provided in this embodiment of the invention is shown below. Figure 4 As shown. The rectangular cross-section auxiliary slot ventilation duct 5 is located at the corresponding position in the low temperature zone of the stator. The inlet of the rectangular cross-section auxiliary slot ventilation duct 5 is rectangular in shape; the rectangular cross-sectional area remains unchanged from the rotor end to the rotor center.

[0035] The alternating radial air duct 6 is located at the corresponding position in the low temperature zone of the stator. The bottom of the alternating radial air duct 6 is connected to the rectangular cross-section sub-slot 5, and the top is connected to the slot wedge ventilation duct 6-3. The alternating radial air duct 6 is formed by alternating single radial straight air duct 6-2 and double radial straight air duct 6-1.

[0036] The annular circumferential air gap partition 8 is made of thermally conductive, non-conductive, and non-magnetic material and is welded onto the stator core 1 stack segment.

[0037] The stepped shape has at least one step, which can be preferably set.

[0038] The minimum number of single radial straight air ducts 6-2 and double radial straight air ducts 6-1 in the alternating radial air ducts 6 is 2, which can be preferably configured.

[0039] The radial heights and circumferential widths of the single radial straight air duct 6-2 and the double radial straight air duct 6-1 are not equal, and can be configured in a preferred manner.

[0040] In summary, this invention provides a ventilation and cooling system for a dual-shaft excitation motor, which can reduce the temperature of the stator and rotor while ensuring a uniform axial temperature distribution between them. Compared to traditional steam turbine generator stators, this invention adds an annular circumferential air gap baffle in the high-temperature region of the stator. This allows hydrogen gas from the dual radial straight air ducts to directly enter the stator radial ventilation grooves without hydrogen cross-flow, thus ensuring a more uniform axial temperature distribution in the stator windings.

[0041] Compared with the traditional rotor structure, the dual-shaft excitation motor ventilation and cooling system of the present invention adopts two cooling structures for the rotor: stepped cross-section secondary slots and double radial straight air ducts, and rectangular cross-section secondary slots and alternating radial air ducts. This improves the uniformity of rotor airflow distribution, effectively reduces the axial temperature of the rotor winding conductors, and avoids the problem of local overheating of the rotor winding conductors.

[0042] Compared with the traditional structure, the ventilation and cooling system of the dual-shaft excitation motor of the present invention adds a circular circumferential air gap baffle, alternating radial air ducts, and stepped cross-section secondary slot ventilation ducts. This allows hydrogen gas from the dual radial straight air ducts to directly enter the stator radial ventilation grooves, thereby making the stator winding temperature distribution as uniform as possible along the axial direction. It also improves the uniformity of rotor air volume distribution, effectively reduces the axial temperature of the rotor winding conductors, and avoids the problem of local overheating of the rotor winding conductors.

[0043] The circumferential air gap baffle allows hydrogen from the dual radial straight air ducts to directly enter the stator radial ventilation grooves without hydrogen cross-flow, thus ensuring a more uniform axial temperature distribution in the stator windings. The stepped cross-section secondary slot ventilation duct and the dual radial straight air ducts increase the uniformity of airflow distribution, reduce air resistance, and lower rotor temperature; the rectangular cross-section secondary slot ventilation duct and alternating radial air ducts also improve the uniformity of airflow distribution, resulting in a more uniform axial temperature distribution in the rotor.

[0044] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of one embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing the present invention.

[0045] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of the present invention.

[0046] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for apparatus or system embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The apparatus and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0047] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A hybrid ventilation and cooling system for a dual-shaft excitation motor, characterized in that, include: Stator core (1), stator radial ventilation groove (2), stepped cross-section secondary slot ventilation duct (3), double radial straight air duct (4), rectangular cross-section secondary slot ventilation duct (5), alternating radial air duct (6), air gap (7) and annular circumferential air gap baffle (8); The annular circumferential air gap baffle (8) is installed in the stator radial ventilation groove (2). The thickness of the annular circumferential air gap baffle (8) is 1 / 4 of the width of the ventilation groove, and the width is 1 / 2 of the length of the air gap. The annular circumferential air gap baffle (8) is set in the radial ventilation groove of the stator high temperature zone. The number of the annular circumferential air gap baffle (8) is 1 / 2 of the number of stator radial ventilation grooves. The stator radial ventilation groove (2) is located between two adjacent stator core (1) stack segments, and the air gap (7) is located between the stator and the rotor; The stepped cross-section auxiliary slot ventilation duct (3) is located at the corresponding position of the high temperature zone of the stator. The inlet of the stepped cross-section auxiliary slot ventilation duct (3) is stepped, that is, the area near the shaft is small and the area near the bottom of the slot is large. The stepped cross-sectional area remains unchanged from the end of the rotor to the center of the rotor. The dual radial straight air duct (4) consists of two long rectangular ventilation ducts inside the rotor winding, located at the corresponding position in the high temperature zone of the stator. The bottom of the dual radial straight air duct (4) is connected to the stepped cross-section auxiliary slot ventilation duct (3), and the upper part of the dual radial straight air duct (4) is connected to the slot wedge ventilation duct. The rectangular cross-section auxiliary slot ventilation duct (5) is located at the corresponding position in the low-temperature zone of the stator. The inlet of the rectangular cross-section auxiliary slot ventilation duct (5) is rectangular in shape, and the rectangular cross-sectional area remains unchanged from the rotor end to the rotor center. The alternating radial air duct (6) is located at the corresponding position of the stator low temperature zone. The bottom of the alternating radial air duct (6) is connected to the rectangular cross-section secondary slot ventilation duct (5). The upper part of the alternating radial air duct (6) is connected to the slot wedge ventilation duct (6-3). The alternating radial air duct (6) is formed by alternating arrangement of single radial straight air duct (6-2) and double radial straight air duct.

2. The system according to claim 1, characterized in that, The annular circumferential air gap partition (8) is made of thermally conductive, non-conductive and non-magnetic material and is welded onto the stator core (1) stack segment.

3. The system according to claim 1, characterized in that, The number of steps in the stepped shape is at least 1.

4. The system according to claim 1, characterized in that, The minimum number of single radial straight air ducts (6-2) and double radial straight air ducts (6-1) in the alternating radial air ducts (6) is 2.

5. The system according to claim 1, characterized in that, The radial heights of the single-radial straight air duct (6-2) and the double-radial straight air duct (6-1) are not equal, and their circumferential widths are not equal.

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