Rotors for synchronous generators

Abstract

The invention relates to a rotor (100) for a synchronous generator, which has a plurality of salient poles (200) regularly arranged on the outer periphery of a rim (300), each pole comprising a coil having two external terminals, the external terminals being respectively referred to as a first terminal (201) and a second terminal (202), the poles being arranged so that two adjacent poles have their respective first terminals (201) or their respective second terminals (202) facing each other, the rotor further comprising at least a first connection (401) between the first terminals (201) and / or at least a second connection (402) between the second terminals, the rotor being characterized in that the first connection (401) and the second connection (402) comprise a plurality of elongated conductive plates, each conductive plate end (A, B) being fixed by a single fixing device on the facing terminals.

Description

Technical Field

[0001] The present invention relates to a rotor of a synchronous generator having a plurality of salient poles, each pole comprising a coil wound around a pole core, the salient poles being connected together so that each pole is circulated by the same excitation current.

[0002] In particular, the invention relates to a device for forming a connection between poles which has low sensitivity to mechanical and thermal stresses generated during rotation of the poles. Background Art

[0003] In a synchronous generator, a rotor is provided with salient poles, each pole comprising a coil wound around a pole core, the salient poles being arranged on the outer periphery of a rim.

[0004] The function of the coils is to generate a magnetic field when an exciting current circulates through them.

[0005] A closed circuit is created by connecting the coils using connecting means, so that the same excitation current circulates in all coils.

[0006] like Figure 1 As depicted in , this connection device 1 can be supported on the rim 2 of the rotor and connected on each side to two adjacent coil terminals 3. This construction is generally intended to be implemented in high-speed rotating synchronous generators.

[0007] However, this arrangement is not satisfactory.

[0008] In fact, during the rotation of the rotor, the poles are subjected to centrifugal forces which cause their relative displacement in the radial direction. These relative displacements induce local mechanical and thermal stresses in the connection device, thus affecting its mechanical integrity and eventually causing its failure.

[0009] Furthermore, the connection is very heavy, which increases the mechanical stress.

[0010] Alternatively, it is specifically proposed that, for a low speed synchronous generator, the connection means are not supported by the rim and are only attached to the terminals of the adjacent coils ( Figure 2 ).

[0011] This connection device generally comprises a metal plate 1 which is connected to terminals 3 at its two ends by means of a plurality of bolts.

[0012] However, this configuration is also unsatisfactory.

[0013] In fact, the relatively high stiffness of the attachments of the connecting means makes them very sensitive to the pole displacements in the longitudinal direction that occur when the rotor rotates.

[0014] The object of the present invention is therefore to provide a rotor having a connection which is less sensitive to mechanical and thermal stresses which may occur during the rotation of the rotor. Summary of the invention

[0015] The above objects are achieved by a rotor for a synchronous generator, which has a plurality of salient poles, which are regularly arranged on the outer periphery of the rim and separated by a space called pole interspace, each pole comprising a coil having two external terminals, which are respectively referred to as first terminals and second terminals, the poles being arranged so that two adjacent poles have their respective first terminals or their respective second terminals facing each other, and the rotor further comprising at least a first connection between the facing first terminals and / or at least a second connection between the facing second terminals.

[0016] The rotor is characterized in that at least one of the first connection and the second connection comprises a plurality of elongated conductive plates preferably not supported by the rim. Each of the ends of the elongated conductive plates is fixed to one of the facing first or second terminals and the other terminal respectively with a single fixing device.

[0017] According to one embodiment, at least one of the first connection and the second connection is flexible. Preferably, at least one of the plurality of elongated plates is flexible. The flexibility enables the connection to flex to accommodate changes in position of adjacent poles when the generator is in use.

[0018] According to one embodiment, at least one of the first connection and the second connection is resilient. Preferably, at least one of the plurality of elongated plates is resilient. When the state of the generator changes, for example when the generator is not in use, the connections are resilient so that they are not permanently deformed by movement of the poles.

[0019] The fixing means may be engaged by two mating holes formed on the end of the elongated conductive plate in question and on the terminal to which said end is fixed.

[0020] According to an embodiment, at least one of the first connection and the second connection is flexible.

[0021] According to one embodiment, at least one of the first connection and the second connection is resilient.

[0022] According to one embodiment, each fixing means comprises a single bolt.

[0023] According to one embodiment, the external terminal is present in the pole gap.

[0024] According to one embodiment, the external terminals are bent or folded so as to impart a convex shape to the elongated conductive plate.

[0025] According to one embodiment, the elongated conductive plate comprises a central section and fixed ends, the central section having a reduced width relative to a width of the fixed ends.

[0026] According to one embodiment, the two facing second terminals (the powered terminals) are connected to an excitation current source.

[0027] According to one embodiment, adjacent salient poles (200) have opposite magnetic polarities.

[0028] According to one embodiment, each elongated conductive plate is made of metal, advantageously copper or aluminium.

[0029] The invention also relates to a synchronous generator comprising a rotor according to the invention.

[0030] Embodiment 1. A rotor (100) for a synchronous generator, comprising a plurality of salient poles (200), the salient poles (200) being regularly arranged on the outer periphery of a rim (300) and separated by spaces called pole gaps, each pole comprising a coil having two external terminals, the two external terminals being respectively referred to as a first terminal (201) and a second terminal (202), the poles being arranged so that two adjacent poles have their respective first terminals (201) or their respective second terminals (202) facing each other, the rotor further comprising at least a first connection (401) between the facing first terminals (201) and / or at least a second connection (402) between the facing second terminals,

[0031] The rotor is characterized in that at least one of the first connection (401) and the second connection (402) comprises a plurality of elongated conductive plates, and each end portion (A, B) thereof is fixed to one and the other of the facing first or second terminals respectively by a fixing device.

[0032] Embodiment 2. A rotor according to embodiment 1, wherein at least one of the first connection and the second connection is flexible.

[0033] Embodiment 3. The rotor of Embodiment 1, wherein at least one of the first connection and the second connection is resilient.

[0034] Embodiment 4. A rotor according to any one of embodiments 1 to 3, wherein the fixing means is engaged by two fitting holes made on the end of the elongated conductive plate in question and on the terminal to which the end is fixed.

[0035] Embodiment 5. A rotor according to any one of embodiments 1 to 3, wherein each fixing device comprises a single bolt.

[0036] Embodiment 6. A rotor according to any one of Embodiment 1, wherein external terminals appear in the pole gap.

[0037] Embodiment 7. The rotor according to any one of Embodiments 1 to 3, wherein the external terminal is bent or folded so as to impart a convex shape to the elongated conductive plate.

[0038] Embodiment 8. A rotor according to any one of embodiments 1 to 3, wherein the elongated conductive plate comprises a central section (C) and fixed ends, the central section having a reduced width relative to the width of the fixed ends.

[0039] Embodiment 9. A rotor according to any one of embodiments 1 to 3, wherein two facing second terminals, the power terminals, are connected to an excitation current source.

[0040] Embodiment 10. A rotor according to any one of Embodiments 1 to 3, wherein adjacent salient poles (200) have opposite magnetic polarities.

[0041] Embodiment 11. A rotor according to any one of embodiments 1 to 3, wherein each elongated conductive plate is made of metal, advantageously copper or aluminium.

[0042] Embodiment 12. A synchronous generator comprising a rotor according to any one of Embodiments 1 to 3. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Other features and advantages will emerge from the following description of an embodiment of a rotor for a synchronous generator according to the invention given as a non-limiting example with reference to the accompanying drawings, in which:

[0044] - Figure 1 is a schematic diagram of a connection device supported on a rim, which is used for a high-speed rotor known in the prior art,

[0045] - Figure 2 is a schematic diagram of a connection device for a low-speed rotor known in the prior art,

[0046] - Figure 3 is a schematic diagram of a section of a rotor according to the invention,

[0047] - Figure 4 is a schematic diagram of a first connection according to the present invention,

[0048] - Figure 5 yes Figure 4 A schematic cross section of the first connection,

[0049] - Figure 6 yes Figure 4 A top view of the first connection. DETAILED DESCRIPTION

[0050] Figure 3 1 represents a rotor 100 for a synchronous generator according to the present invention.

[0051] Specifically, the rotor 100 includes a plurality of salient poles 200 that are regularly disposed on an outer circumference of the rim 300 .

[0052] Each salient pole 200 includes a coil that generates a magnetic field when an excitation current circulates through it.

[0053] Each coil includes two external terminals, namely first terminals 201 ( Figure 3 ,4,5,6 and the second terminal 202 ( Figure 3 ).

[0054] Specifically, two adjacent poles 200 are arranged so that their respective first terminals 201 or their respective second terminals 202 face each other.

[0055] In other words, two adjacent salient poles 200 are arranged to have opposite polarities.

[0056] Advantageously, the external terminal emerges from the pole in the pole gap.

[0057] The rotor 100 according to the present invention further comprises at least a first connection 401 between the first terminals 201 and / or at least a second connection 402 between the second terminals 202 ( Figure 3 ).

[0058] The first and second connections comprise a plurality of elongated conductive plates which are advantageously not supported by the rim.

[0059] In particular, each elongated conductive plate comprises a central section C and two end portions A and B, each end portion being fixed to one and the other of the facing terminals respectively by fixing means.

[0060] The first connection and / or the second connection may be flexible.

[0061] "Flexible" means that the connection can overcome some deformation when the forces generated from the rotation of the rotor are applied to them. Specifically, this means that the connection with dimensions and / or mechanical properties (such as Young's modulus) is adjusted so that it will not break when the forces generated from the rotation of the rotor are applied to them.

[0062] A skilled person having his general knowledge is able to select the most suitable materials and dimensions to provide a flexible first and or second connection that is compatible with the implementation in the context of the present invention.

[0063] Advantageously, the first connection and / or the second connection may be resilient.

[0064] "Resilience" means that the connections can overcome some deformation when forces from the rotation of the rotor are applied to them, but the deformation is limited to elastic. Specifically, this means that the connections have dimensions and / or mechanical properties (such as Young's modulus) that are adjusted so that they do not break when forces from the rotation of the rotor are applied to them.

[0065] A skilled person having his general knowledge is able to select the most suitable materials and dimensions to provide a resilient connection that is compatible with the embodiments in the context of the present invention.

[0066] Advantageously, the fixing means are engageable by means of two cooperating holes formed on the end of the elongated conductive plate in question and on the terminal to which said end is fixed.

[0067] For example, the fixing means may include, but are not limited to, bolt / nut assemblies, screws, rivets ( Figure 6 ).

[0068] Advantageously, each elongated conductive plate is made of metal, for example, copper or aluminum.

[0069] Considering a single fixing means (at each end) for attaching the elongated conductive plate to two facing terminals, such as a single bolt, improves the flexibility of the connection, which is therefore less sensitive to saliency displacements.

[0070] Furthermore, the fact that the connection between the facing terminals is ensured by a plurality of elongated conductive plates reduces overall the impact of the quality of said connection and therefore reduces the sensitivity to the stresses caused by the rotation of the rotor.

[0071] In a specific embodiment, the external terminal is bent or folded so as to impart a convex shape to the elongated conductive plate. Figure 5 ). This configuration further improves the flexibility of the connection means and thus reduces their sensitivity to relative displacements of the salient poles.

[0072] Advantageously, a central section C of the elongated conductive plate has a reduced width relative to the end portions A and B.

[0073] This reduced width makes it possible to form ventilation spaces between the elongated conductive plates. This ventilation limits the temperature increase due to the heating that occurs during the rotation of the rotor.

[0074] The rotor may also include a current source connected to the two second terminals 202 (the power terminals).

[0075] The invention also relates to a synchronous generator, in particular a synchronous hydrogen generator, comprising a rotor according to the invention.

Claims

1. A rotor (100) for a synchronous generator, comprising a plurality of salient poles (200), the salient poles (200) being regularly arranged on the outer periphery of a rim (300) and separated by spaces called pole gaps, each pole comprising a coil having two external terminals, the two external terminals being respectively called first terminals (201) and second terminals (202), the poles being arranged so that two adjacent poles have their respective first terminals (201) or their respective second terminals (202) facing each other, the rotor further comprising at least a first connection (401) between the facing first terminals (201) and / or at least a second connection (402) between the facing second terminals, The rotor is characterized in that at least one of the first connection (401) and the second connection (402) comprises a plurality of elongated conductive plates, and each end (A, B) of the elongated conductive plates is fixed to one and the other of the facing first or second terminals respectively with a single fixing device, the elongated conductive plates comprising a central section (C) and fixed ends, the central section having a reduced width relative to the width of the fixed ends.

2. The rotor according to claim 1, wherein: At least one of the first connection and the second connection is flexible.

3. The rotor according to claim 1, wherein: At least one of the first connection and the second connection is resilient.

4. The rotor according to any one of claims 1 to 3, wherein: Said single fixing means engages via two cooperating holes made on the end of the elongated conductive plate in question and on said terminal to which said end is fixed.

5. The rotor according to any one of claims 1 to 3, wherein: The single fixing means comprises a single bolt.

6. The rotor according to claim 1, wherein: External terminals appear in the interpolar gap.

7. A rotor according to any one of claims 1 to 3, wherein: The external terminal is bent or folded so as to impart a convex shape to the elongated conductive plate.

8. The rotor according to any one of claims 1 to 3, wherein: The two facing second terminals are connected to an excitation current source, and the two facing second terminals are power terminals.

9. The rotor according to any one of claims 1 to 3, wherein: Adjacent salient poles (200) have opposite magnetic polarities.

10. The rotor according to any one of claims 1 to 3, wherein: Each elongated conductive plate is made of metal, advantageously comprising copper or aluminium.

11. A synchronous generator comprising a rotor according to any one of claims 1 to 3.

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