gas turbine

Abstract

The objective is to provide a gas turbine that prevents the need for a large-scale design due to the structure required to obtain rotational speed. [Solution] The gas turbine includes an AC generator 7 which includes a rotor, a rotating shaft connected to the rotor so as to rotate integrally with the rotor, a rotor which rotates integrally with the rotating shaft and includes permanent magnets, and a stator; a main power line E connected to the AC generator through which the current generated by the AC generator flows; a detection power line 110 connected to the main power line; and a rotation speed calculation device 120 connected to the detection power line which calculates the rotation speed of the rotating shaft based on the behavior of the voltage or current generated by the AC generator.

Description

Technical Field

[0001] The present disclosure relates to a gas turbine.

Background Art

[0002] Patent Document 1 discloses an automatic inspection device for a rotational speed detection device of a gas turbine engine for driving a generator. The automatic inspection device compares the rotational speed of the gas turbine engine detected by the rotational speed detection device with a rotational speed conversion value obtained from the generated voltage frequency of the generator detected by the frequency detection device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, the rotational speed of a gas turbine engine is detected using a rotational speed detection device. The rotational speed detection device includes mechanical, optical, magnetic, etc., but all have limitations on the heat-resistant temperature. Therefore, when incorporating the rotational speed detection device into a gas turbine engine, it is necessary to sufficiently distance the rotational speed detection device from the heat generation source so that the temperature of the rotational speed detection device does not exceed the heat-resistant temperature due to the generated heat of the gas turbine engine, which may lead to an increase in the size of the gas turbine engine.

[0005] One aspect of the present disclosure aims to provide a gas turbine that prevents an increase in size due to the structure for obtaining the rotational speed.

Means for Solving the Problems

[0006] A gas turbine according to one aspect of the present disclosure includes an AC generator comprising a rotor, a rotating shaft connected to the rotor so as to rotate integrally with the rotor, a rotor that rotates integrally with the rotating shaft and includes permanent magnets, and a stator; a main power line connected to the AC generator through which the current generated by the AC generator flows; a detection power line connected to the main power line; and a rotational speed calculation device connected to the detection power line, which calculates the rotational speed of the rotating shaft based on the behavior of the voltage or current generated by the AC generator. [Effects of the Invention]

[0007] According to one aspect of this disclosure, it is possible to prevent the device from becoming larger due to the structure for acquiring the rotational speed. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a cross-sectional view showing an example of the configuration of a gas turbine according to an embodiment. [Figure 2] Figure 2 is an enlarged cross-sectional view showing the structure from the low-pressure side compressor to the high-pressure side compressor in Figure 1. [Figure 3] Figure 3 is a block diagram showing an example of the electrical configuration of the rotational speed detection system and generator according to the embodiment. [Figure 4] Figure 4 shows an example of the voltage waveform of AC power before and after rectification by a power converter. [Modes for carrying out the invention]

[0009] Illustrative embodiments of the present disclosure are described below with reference to the drawings. The embodiments described below are all comprehensive or specific examples. Components in the following embodiments that are not described in the independent claim representing the highest-level concept are described as optional components. The figures in the accompanying drawings are schematic and not necessarily strictly illustrative. In each figure, substantially identical components are denoted by the same reference numerals, and redundant descriptions may be omitted or simplified.

[0010] In the following explanation, axial direction X refers to the direction in which the axis L of the rotation shaft 2 of the gas turbine 1 extends. Furthermore, "front" refers to the side of the gas turbine 1 from which air is introduced from the outside in axial direction X, and "rear" refers to the side of the gas turbine 1 from which exhaust gas is discharged in axial direction X. Axial direction X is the front-to-back direction of the gas turbine 1.

[0011] Figure 1 is a cross-sectional view showing an example of the configuration of a gas turbine 1 according to an embodiment. As shown in Figure 1, in this embodiment, the gas turbine 1 is a twin-shaft gas turbine. The gas turbine 1 is used as an engine for aircraft such as unmanned aerial vehicles, but the application of the gas turbine 1 is not limited to aircraft. The gas turbine 1 can be used as a turbofan engine.

[0012] The gas turbine 1 comprises a rotating shaft 2, a fan 3, a compressor 4, a combustor 5, a turbine 6, a generator 7, and a casing 8 which is the housing. The fan 3 is connected to the front of the rotating shaft 2 and rotates together with the rotating shaft 2. The compressor 4, combustor 5, and turbine 6 are arranged in this order from front to rear along the rotating shaft 2. The casing 8 houses all or part of the rotating shaft 2, fan 3, compressor 4, combustor 5, turbine 6, and generator 7.

[0013] In this embodiment, the rotating shaft 2 includes a low-pressure shaft 2A and a high-pressure shaft 2B extending in the axial direction X. The high-pressure shaft 2B is arranged on the same axis as the low-pressure shaft 2A and is rotatable relative to the low-pressure shaft 2A. The high-pressure shaft 2B is a tubular hollow shaft. The low-pressure shaft 2A is inserted into the hollow space of the high-pressure shaft 2B and penetrates the hollow space. The low-pressure shaft 2A is longer in the front-rear direction than the high-pressure shaft 2B, and the front end 2Aa and rear end 2Ab of the low-pressure shaft 2A are exposed to the outside from the front end 2Ba and rear end 2Bb of the high-pressure shaft 2B, respectively. The front end 2Aa of the low-pressure shaft 2A is connected to the fan 3.

[0014] The compressor 4 includes a low-pressure side compressor 4A and a high-pressure side compressor 4B located behind the low-pressure side compressor 4A. The low-pressure side compressor 4A is an axial flow compressor and includes rotor blades connected to rotate integrally with the low-pressure shaft 2A. In this embodiment, the low-pressure side compressor 4A includes two rotor blades aligned in the axial direction X. The connection between the two rotor blades of the low-pressure side compressor 4A and the low-pressure shaft 2A is located between the front end 2Aa of the low-pressure shaft 2A and the front end 2Ba of the high-pressure shaft 2B. In this embodiment, the two rotor blades of the low-pressure side compressor 4A are connected to the front end 2Aa of the low-pressure shaft 2A together with the fan 3, although they may be connected to the low-pressure shaft 2A at a different position from the fan 3, further rearward from the front end 2Aa.

[0015] The high-pressure side compressor 4B is a centrifugal compressor and includes a rotor connected to the high-pressure shaft 2B so as to rotate integrally with it. In this embodiment, the high-pressure side compressor 4B includes one rotor. The connection between the rotor of the high-pressure side compressor 4B and the high-pressure shaft 2B is located in front of the combustor 5. The types of low-pressure side compressor 4A and high-pressure side compressor 4B are not limited to axial flow compressors and centrifugal compressors. A diffuser 12 is arranged on the outer circumference of the high-pressure side compressor 4B to send the air flowing out of the high-pressure side compressor 4B to the rear. Behind the diffuser 12 is the combustor 5. The combustor 5 is a back-flow type combustor.

[0016] The turbine 6 includes a high-pressure side turbine 6B and a low-pressure side turbine 6A located behind the high-pressure side turbine 6B. The low-pressure shaft 2A mechanically connects the low-pressure side compressor 4A to the low-pressure side turbine 6A. The high-pressure shaft 2B mechanically connects the high-pressure side compressor 4B to the high-pressure side turbine 6B. The low-pressure side turbine 6A includes rotor blades connected to the low-pressure shaft 2A to rotate integrally with it. In this embodiment, the low-pressure side turbine 6A includes two rotor blades aligned in the axial direction X. The connection between the two rotor blades of the low-pressure side turbine 6A and the low-pressure shaft 2A is located between the rear end 2Bb of the high-pressure shaft 2B and the rear end 2Ab of the low-pressure shaft 2A. The low-pressure side turbine 6A can rotate the low-pressure side compressor 4A and the fan 3 via the low-pressure shaft 2A.

[0017] The high-pressure turbine 6B includes a rotor blade connected to rotate integrally with the high-pressure shaft 2B. In this embodiment, the high-pressure turbine 6B includes one rotor blade. The connection portion between the rotor blade of the high-pressure turbine 6B and the high-pressure shaft 2B is located between the high-pressure compressor 4B and the rear end portion 2Bb of the high-pressure shaft 2B. The high-pressure turbine 6B can rotate the high-pressure compressor 4B via the high-pressure shaft 2B.

[0018] The casing 8 includes a cylindrical outer shell 8A and an inner shell 8B arranged concentrically with each other. The inner shell 8B houses the compressor 4, the combustor 5, the turbine 6, and the generator 7. A cylindrical bypass flow path B is formed between the inner shell 8B and the outer shell 8A.

[0019] The gas turbine 1 includes a first cylinder body 9 extending in the axial direction X from the fan 3 to the high-pressure compressor 4B inside the inner shell 8B. The outer diameter and the inner diameter of the first cylinder body 9 are reduced from the front to the rear. The first cylinder body 9 defines a part of a compressed air flow path R from the low-pressure compressor 4A toward the high-pressure compressor 4B between the first cylinder body 9 and the inner shell 8B. The outer peripheral surface of the first cylinder body 9 faces the compressed air flow path R. The generator 7 is arranged inside the first cylinder body 9. The first cylinder body 9 is connected to the inner shell 8B by a plurality of struts 9A and supported by the inner shell 8B. The rotor blades of the low-pressure compressor 4A and the rotor blades of the high-pressure compressor 4B are located in the compressed air flow path R.

[0020] The gas turbine 1 includes a second cylinder body 10 extending in the axial direction X from the high-pressure turbine 6B to the low-pressure turbine 6A inside the inner shell 8B. The second cylinder body 10 defines at least a part of a gas flow path G extending rearward from the combustor 5 between the second cylinder body 10 and the inner shell 8B inside the inner shell 8B. The outer peripheral surface of the second cylinder body 10 faces the gas flow path G.The second cylinder body 10 is connected to the inner shell 8B via a plurality of struts 10A etc. and supported by the inner shell 8B. The gas flow path G merges with the bypass flow path B behind the low-pressure turbine 6A. The rotor blades of the low-pressure turbine 6A and the rotor blades of the high-pressure turbine 6B are located in the gas flow path G.

[0021] The gas turbine 1 includes a strut housing 11. Part or all of the strut housing 11 is housed in the outer casing 8A. The strut housing 11 is located in front of the high-pressure compressor 4B. In the present embodiment, the strut housing 11 is located between the generator 7 and the high-pressure compressor 4B in the axial direction X. The strut housing 11 extends in the axial diameter direction, which is the radial direction of the axis L, from the first cylinder 9 to the outer casing 8A. The strut housing 11 is connected to the outer casing 8A, the inner casing 8B, and the first cylinder 9, and connects the outer casing 8A, the inner casing 8B, and the first cylinder 9 to each other.

[0022] The strut housing 11 includes an outer casing portion 11a, an inner casing portion 11b, a cylinder portion 11c, and a plurality of struts 11d. The outer casing portion 11a is connected to the outer casing 8A and forms part of the outer casing 8A. The outer casing portion 11a has a cylindrical shape extending in the circumferential direction around the axis L, similar to the outer casing 8A. The inner casing portion 11b is connected to the inner casing 8B and forms part of the inner casing 8B. The inner casing portion 11b has a cylindrical shape extending in the circumferential direction, similar to the inner casing 8B. The cylinder portion 11c is connected to the first cylinder 9 and forms part of the first cylinder 9. The cylinder portion 11c has a cylindrical shape extending in the circumferential direction, similar to the first cylinder 9. The plurality of struts 11d extend radially in the axial diameter direction from the cylinder portion 11c through the inner casing portion 11b to the outer casing portion 11a. Each of the plurality of struts 11d connects the outer casing portion 11a, the inner casing portion 11b, and the cylinder portion 11c to each other.

[0023] A portion of the air drawn in by fan 3 flows through bypass channel B and is discharged to the rear. The remaining air drawn in by fan 3 flows through compressed air channel R and enters the low-pressure compressor 4A. The air passes sequentially through the low-pressure compressor 4A and the high-pressure compressor 4B within the compressed air channel R and enters the combustor 5 via the diffuser 12. The combustion gas discharged from the outlet of the combustor 5 passes through the nozzle unit 13 and enters the gas channel G. The combustion gas passes sequentially through the high-pressure turbine 6B and the low-pressure turbine 6A within the gas channel G and is discharged to the rear. The combustion gas discharged from gas channel G merges with the air discharged from bypass channel B, is accelerated by the air, and is discharged to the outside of the casing 8.

[0024] The high-pressure side turbine 6B rotates under the influence of the high-temperature, high-pressure combustion gas flow immediately after it flows out of the combustor 5. The low-pressure side turbine 6A rotates under the influence of the combustion gas flow that has been cooled and depressurized as it passes through the high-pressure side turbine 6B. For this reason, the high-pressure side turbine 6B rotates at a higher rotational speed than the low-pressure side turbine 6A. Furthermore, the high-pressure side compressor 4B, which is rotated by the high-pressure side turbine 6B, rotates at a higher rotational speed than the low-pressure side compressor 4A, which is rotated by the low-pressure side turbine 6A. Rotational speed refers to the number of rotations per unit time. The air flowing through the compressed air passage R is pressurized by the low-pressure side compressor 4A, and then pressurized to an even higher pressure by the high-pressure side compressor 4B before flowing into the combustor 5. Because the high-pressure side compressor 4B is affected by the heat generated in the combustor 5, it is exposed to a higher temperature and pressure environment than the low-pressure side compressor 4A.

[0025] Figure 2 is an enlarged cross-sectional view showing the structure from the low-pressure side compressor 4A to the high-pressure side compressor 4B in Figure 1. As shown in Figure 2, the generator 7 generates electricity when the generator shaft 7A of the generator 7 is driven by the rotational driving force of the rotating shaft 2. In this embodiment, the generator shaft 7A is located coaxially with the low-pressure shaft 2A and the high-pressure shaft 2B. The generator 7 may also have a starter function that rotates the rotating shaft 2 when the gas turbine 1 is started. In this case, the generator 7 is a motor generator. The generator 7 is located inside the first cylinder 9 and in front of the high-pressure side compressor 4B. In this embodiment, the generator 7 is located between the low-pressure side compressor 4A and the high-pressure side compressor 4B.

[0026] The generator 7 includes a generator shaft 7A, a rotor 7B that rotates integrally with the generator shaft 7A, a stator 7C located around the rotor 7B, and a generator housing 7D. The generator shaft 7A and rotor 7B are located inside the stator 7C. The generator shaft 7A is a tubular hollow shaft extending in the axial direction X. The low-pressure shaft 2A is inserted into and penetrates the hollow space of the generator shaft 7A. The front end 2Ba of the high-pressure shaft 2B is inserted into the hollow space of the generator shaft 7A. The rear end 7Ab of the generator shaft 7A is connected to the front end 2Ba of the high-pressure shaft 2B to transmit rotational forces around axis L. The generator shaft 7A rotates together with the high-pressure shaft 2B around axis L.

[0027] In this embodiment, the rear end portion 7Ab of the generator shaft 7A and the front end portion 2Ba of the high-voltage shaft 2B are spline-connected. The inner circumferential surface of the rear end portion 7Ab of the generator shaft 7A includes a plurality of grooves spaced apart in the circumferential direction and extending in the axial direction X, which function as an internal spline. The outer circumferential surface of the front end portion 2Ba of the high-voltage shaft 2B includes a plurality of band-shaped projections spaced apart in the circumferential direction and extending in the axial direction X, which function as an external spline.

[0028] The rotor 7B is a cylindrical body having an internal space extending in the axial direction X. The generator shaft 7A is inserted into and passes through the internal space of the rotor 7B. The rotor 7B is coupled to the generator shaft 7A and rotates together with the generator shaft 7A around the axis L. The rotor 7B contains permanent magnets, and the stator 7C contains windings. The rotor 7B is surrounded by the stator 7C. In this embodiment, the generator 7 is a permanent magnet type AC generator.

[0029] Examples of permanent magnets may include non-rare-earth metal magnets, ferrite magnets, and rare-earth magnets. The generator 7 is located near the high-pressure side compressor 4B and is affected by the high-temperature environment of the high-pressure side compressor 4B. The high-pressure side compressor 4B is located near the combustor 5 and is therefore in a high-temperature environment. For this reason, in this embodiment, the permanent magnet is a neodymium magnet or a cobalt magnet. Neodymium magnets are one type of non-rare-earth metal magnet. Neodymium magnets generate the strongest magnetic force among existing permanent magnets. Neodymium magnets can generate sufficient magnetic force even in the high-temperature environment that the generator 7 is subjected to, improving the power generation capacity and durability of the generator 7. Cobalt magnets, also called samarium-cobalt magnets, are one type of rare-earth magnet. Cobalt magnets have high heat resistance and thermal stability. Cobalt magnets can generate sufficient magnetic force even in the high-temperature environment that the generator 7 is subjected to, improving the power generation capacity and durability of the generator 7.

[0030] The generator housing 7D houses the rotor 7B and the stator 7C. The generator housing 7D covers the rotor 7B and the stator 7C from at least the outside in the radial direction. The generator housing 7D may also cover the rotor 7B and the stator 7C from both sides in the axial direction X.

[0031] As shown in Figure 1, the gas turbine 1 comprises a plurality of bearings 20A, 20B, and 20C, and bearing housings 30A and 30B that support the plurality of bearings 20A, 20B, and 20C. In this embodiment, the plurality of bearings 20A, 20B, and 20C are radial bearings, for example, radial ball bearings or radial roller bearings.

[0032] The first bearing housing 30A extends axially X within the first cylindrical body 9 between the fan 3 and the high-pressure side compressor 4B. The first bearing housing 30A extends circumferentially and surrounds a portion of the bearing 20A, a portion of the bearing 20B, and the generator 7 from the radially outer side. The first bearing housing 30A is connected to the first cylindrical body 9 by a plurality of struts and is supported by the first cylindrical body 9. The rear of the first bearing housing 30A is connected to the cylindrical portion 11c of the strut housing 11.

[0033] The second bearing housing 30B is located aft of the first bearing housing 30A in the axial direction X. Inside the second cylinder 10, the second bearing housing 30B extends axially X between the high-pressure side turbine 6B and the low-pressure side turbine 6A. The second bearing housing 30B surrounds a portion of the bearing 20A and a portion of the bearing 20B from the radially outer side. The second bearing housing 30B is connected to the second cylinder 10 by a plurality of struts and is supported by the second cylinder 10.

[0034] Multiple bearings 20A are located at the front and rear of the low-pressure shaft 2A and rotatably support the low-pressure shaft 2A from the radially outer side. Multiple bearings 20B are located at the front and rear of the high-pressure shaft 2B and rotatably support the high-pressure shaft 2B from the radially outer side. The bearings 20A at the front of the low-pressure shaft 2A and the bearings 20B at the front of the high-pressure shaft 2B are fixed to the inner surface of the first bearing housing 30A and supported by the first bearing housing 30A from the radially outer side.

[0035] Multiple bearings 20C are located at the front and rear of the generator shaft 7A and rotatably support the generator shaft 7A from the radially outer side. The multiple bearings 20C are fixed to the inner surface of the generator housing 7D and supported by the generator housing 7D from the radially outer side. The generator housing 7D is fixed to the first bearing housing 30A and supported by the first bearing housing 30A in the axial X direction and the radial direction.

[0036] The stator 7C is located around the rotor 7B and includes a cylindrical core 7Ca containing a magnetic material. The core 7Ca has a plurality of teeth arranged in an annular pattern on its inner surface, spaced apart from each other in the circumferential direction of the core 7Ca. The stator 7C also includes a conductive winding 7Cb that is wound around the plurality of teeth.

[0037] The conductors extending from the windings 7Cb of multiple teeth are bundled in front of or behind the stator 7C, and in this embodiment, they are bundled in front. Conductors of the same phase are connected and bundled together. The generator 7 generates AC power of multiple phases, and in this embodiment, it is a three-phase AC generator that generates three-phase AC power. For this reason, the conductors corresponding to the U phase, V phase, and W phase are bundled into three conductor bundles 7Cc. The three conductor bundles 7Cc are covered with an electrical insulating material.

[0038] The three wire bundles 7Cc extend circumferentially within the generator housing 7D, then penetrate the walls of the generator housing 7D and are brought out to the outside of the generator housing 7D and into the first cylindrical body 9. In this embodiment, the three wire bundles 7Cc extend circumferentially near the front end wall of the generator housing 7D. In this embodiment, each wire bundle 7Cc is processed to have a cable structure in the process of reaching the outside of the generator housing 7D. The three wire bundles 7Cc are part of the main power line E.

[0039] The ends of the three wire bundles 7Cc are physically and electrically connected to the generator connector 7F. The generator connector 7F is located outside the generator housing 7D and inside the first cylinder 9. Inside the first cylinder 9, the generator connector 7F is mechanically and electrically connected to the first external connector 51 of the external wire 50 that extends from the outside to the inside of the gas turbine 1. The external wire 50 includes three cables 52, each corresponding to and electrically connected to the three wire bundles 7Cc. The generator connector 7F, the first external connector 51, and the cables 52 are part of the main wire E.

[0040] The strut housing 11 includes a hollow passage 11e that extends through the strut housing 11. The hollow passage 11e extends through the outer shell portion 11a, the inner shell portion 11b, the cylindrical portion 11c, and the strut 11d. The hollow passage 11e communicates with the internal space of the first bearing housing 30A through a wire hole 30Ab that penetrates the wall of the first bearing housing 30A.

[0041] The three cables 52 extend outside the outer shell portion 11a through the hollow passage 11e. The external wire 50 includes a relay connector 53 located in the middle of the three cables 52 and a second external connector 54 connected to the ends of the three cables 52 outside the outer shell portion 11a. For example, the second external connector 54 may be electrically connected to an electric auxiliary device provided with the gas turbine 1 that consumes power. Examples of electric auxiliary devices may include a fuel pump that supplies fuel to the combustor 5, a fuel heater that raises the temperature of the fuel, and measuring instruments. The relay connector 53 is located where the hollow passage 11e penetrates the outer shell portion 11a and is fixed to the outer shell portion 11a. The relay connector 53 and the second external connector 54 are part of the main wire E.

[0042] Figure 3 is a block diagram showing an example of the electrical configuration of the rotational speed detection system 100 and the generator 7 according to an embodiment. As shown in Figure 3, the gas turbine 1 includes a rotational speed detection system 100 for detecting the rotational speed of the generator shaft 7A of the generator 7, and a control device 200 for controlling the gas turbine 1. The control device 200 controls the electric auxiliary equipment of the gas turbine 1. The control device 200 includes a processing circuit including a processor and memory.

[0043] In the following, the U-phase conductor bundle 7Cc may be referred to as "conductor bundle 7Cu," the V-phase conductor bundle 7Cc as "conductor bundle 7Cv," and the W-phase conductor bundle 7Cc as "conductor bundle 7Cw." The U-phase cable 52 may be referred to as "cable 52u," the V-phase cable 52 as "cable 52v," and the W-phase cable 52 as "cable 52w." When conductor bundles 7Cu, 7Cv, and 7Cw are not distinguished, "conductor bundle 7Cc" is used. When cables 52u, 52v, and 52w are not distinguished, "cable 52" is used.

[0044] The rotational speed detection system 100 includes a detection wire 110 and a rotational speed calculation device 120. The detection wire 110 includes detection wires 110u and 110v corresponding to the U-phase and V-phase, respectively, of the power generated by the generator 7. In this embodiment, however not limited, the detection wire 110 also includes a detection wire 110w corresponding to the W-phase of the power generated by the generator 7. The detection wire 110u is electrically connected to the conductor bundle 7Cu and the cable 52u. The detection wire 110v is electrically connected to the conductor bundle 7Cv and the cable 52v. The detection wire 110w is electrically connected to the conductor bundle 7Cw and the cable 52w.

[0045] The rotational speed calculation device 120 is signal-connected to the control device 200 and outputs the calculation result to the control device 200. The rotational speed calculation device 120 is electrically connected to the detection wire 110. Based on the behavior of the voltage or current generated by the generator 7, which is acquired via the detection wire 110, the rotational speed calculation device 120 calculates the rotational speed of the generator shaft 7A and detects the rotational speed of the high-voltage shaft 2B based on the rotational speed of the generator shaft 7A.

[0046] In this embodiment, the rotational speed calculation device 120 includes a first rotational speed calculation device 120A that calculates the rotational speed of the generator shaft 7A based on the behavior of the voltage generated by the generator 7, and a second rotational speed calculation device 120B that calculates the rotational speed of the generator shaft 7A based on the behavior of the current generated by the generator 7. The rotational speed detection system 100 includes a current-voltage converter 140 that assists the calculation of the second rotational speed calculation device 120B.

[0047] The first rotational speed calculation unit 120A is electrically connected to the detection wires 110u and 110v. The second rotational speed calculation unit 120B is electrically connected to the detection wire 110w via the current-voltage converter 140. The current-voltage converter 140 is electrically connected to the detection wire 110w. The current-voltage converter 140 and the second rotational speed calculation unit 120B are electrically or signally connected to each other by the detection wires 110a and 110b.

[0048] In this embodiment, the rotational speed of the generator shaft 7A is the same as the rotational speed of the high-voltage shaft 2B. In this specification and claims, “rotational speed” is expressed as “rotational speed.” Rotational speed may be expressed as angular velocity or the number of rotations per unit time. For example, the unit time may be 1 minute.

[0049] The first rotational speed calculation device 120A acquires the voltage behavior between the detection wires 110u and 110v, and calculates the rotational speed of the generator shaft 7A based on the acquired voltage behavior. The first rotational speed calculation device 120A calculates the period of one or more voltage waveforms from the voltage behavior, and calculates the rotational speed of the rotor 7B, i.e., the rotational speed of the generator shaft 7A, from the periods of one or more voltage waveforms. When the first rotational speed calculation device 120A calculates the rotational speed of the rotor 7B from multiple periods of multiple voltage waveforms, it may calculate the rotational speed of the rotor 7B based on statistical values ​​of the multiple periods. Examples of statistical values ​​may include the mean, maximum, minimum, mode, and median.

[0050] For example, the first rotational speed calculation device 120A calculates the number of zero-crossings per unit time in the voltage waveform where the voltage value becomes 0, and calculates the period of one or more voltage waveforms based on this number. The first rotational speed calculation device 120A may also calculate the number of zero-crossings per unit time using a combination of the time required for the three zero-crossings that constitute the period of one voltage waveform and the number of zero-crossings (3), or a combination of the time required for the multiple zero-crossings that constitute multiple periods of multiple voltage waveforms and the number of zero-crossings. The first rotational speed calculation device 120A may use a voltage value other than 0 as a reference value for calculating the period of the voltage waveform. In this case, the first rotational speed calculation device 120A may calculate the number of times per unit time in the voltage waveform where the voltage value becomes the reference value, and calculate the period of one or more voltage waveforms based on this number. Such a first rotational speed calculation device 120A may include a V / F (voltage / frequency) converter circuit that takes a voltage signal as an input signal and the frequency signal of the voltage signal as an output signal.

[0051] The second rotational speed calculation device 120B acquires the behavior of the current flowing through the detection wire 110w and calculates the rotational speed of the generator shaft 7A based on the acquired current behavior. The second rotational speed calculation device 120B receives a voltage signal converted from the current flowing through the detection wire 110w from the current-to-voltage converter 140. The current-to-voltage converter 140 converts the current flowing through the detection wire 110w into a voltage signal. The current-to-voltage converter 140 converts the current into a voltage by detecting the induced voltage generated by a change in the magnetic field created by the current. For example, the current-to-voltage converter 140 may include a coil around which the detection wire 110w is wound, and the induced voltage generated in the coil by the current flowing through the detection wire 110w may be applied to the detection wires 110a and 110b. Alternatively, the current-to-voltage converter 140 may include a magnetic sensor that detects the strength and direction of the magnetic field created by the current flowing through the detection wire 110w. The current-voltage converter 140 may pass the detection signal from the magnetic sensor through the detection wires 110a and 110b, or it may convert the detection signal into a voltage signal and apply the voltage signal to the detection wires 110a and 110b.

[0052] The second rotational speed calculation device 120B calculates the period of one or more voltage waveforms from the voltage behavior indicated by the voltage signals of the detection wires 110a and 110b, and calculates the rotational speed of the rotor 7B, i.e., the rotational speed of the generator shaft 7A, from the period of one or more voltage waveforms. The second rotational speed calculation device 120B may calculate the rotational speed of the rotor 7B using the same calculation method as described for the first rotational speed calculation device 120A. Such a second rotational speed calculation device 120B may include a V / F (voltage / frequency) converter circuit that takes a voltage signal as an input signal and the frequency signal of the voltage signal as an output signal.

[0053] The rotational speed calculation units 120A and 120B include processing circuits, including a processor and memory. Examples of processors in the rotational speed calculation units 120A and 120B may include a CPU (Central Processing Unit), a DSP (Digital Signal Processor), ASICs (Application-Specific Integrated Circuits), and FPGAs (Field Programmable Gate Arrays). The rotational speed calculation units 120A and 120B process the output signals of the circuits to generate a digital or analog signal indicating the rotational speed of the high-pressure shaft 2B and output it to the control device 200. The control device 200 controls the rotational speeds of the low-pressure shaft 2A and the high-pressure shaft 2B by controlling the operation of electric auxiliary equipment, such as the fuel pump and fuel heater, based on the digital or analog signal. Examples of processors in the control device 200 may include the same ones as those in the rotational speed calculation units 120A and 120B.

[0054] The gas turbine 1 includes a power converter 60 that is electrically connected to cables 52u, 52v, and 52w. In this embodiment, conversion connectors 62 at the ends of the three cables 61 extending from the power converter 60 are mechanically and electrically connected to a second external connector 54. Hereinafter, the U-phase cable 61 may be referred to as "cable 61u", the V-phase cable 61 as "cable 61v", and the W-phase cable 61 as "cable 61w". When cables 61u, 61v, and 61w are not distinguished, "cable 61" is used. The cables 61 and the conversion connectors 62 are part of the main power line E.

[0055] The power converter 60 converts the three-phase AC power generated by the generator 7 into DC power. The power converter 60 rectifies the AC voltage and converts it into DC voltage. In this embodiment, the rectification performed by the power converter 60 is full-wave rectification, but is not limited to this. For example, the rectification performed by the power converter 60 may be half-wave rectification or pulse width modulation (PWM). The power converter 60 is also called an AC-DC converter. The power converter 60 includes a transformer-type or switching-type power conversion circuit. The power converter 60 may include a full-wave rectifier circuit, a half-wave rectifier circuit, or a PWM circuit. The power converter 60 supplies the converted DC power to electric auxiliary equipment and the like.

[0056] The power converter 60 rectifies the negative voltage portion of the input voltage into a positive voltage using full-wave rectification control. As a result, the voltages in cables 61u, 61v, and 61w are filtered, and noise contained in the positive and negative voltage portions of the voltage is removed. Similarly, the power converter 60 performs filtering to remove noise contained in the positive and negative current portions of the input current using full-wave rectification control. Filtered voltage signals and current signals can be input to the first rotational speed calculation device 120A and the current-voltage converter 140 via detection wires 110u, 110v, and 110w. The second rotational speed calculation device 120B can receive a voltage signal converted from the filtered current signal. The input voltage signal may be a de-noised signal.

[0057] The detection wire 110u is connected to the conductor bundle 7Cu, cable 52u, cable 61u, generator connector 7F, first external connector 51, intermediate connector 53, second external connector 54, or conversion connector 62. The detection wire 110v is connected to the conductor bundle 7Cv, cable 52v, cable 61v, generator connector 7F, first external connector 51, intermediate connector 53, second external connector 54, or conversion connector 62. The detection wire 110w is connected to the conductor bundle 7Cw, cable 52w, cable 61w, generator connector 7F, first external connector 51, intermediate connector 53, second external connector 54, or conversion connector 62. In this embodiment, the detection wires 110u, 110v, and 110w are connected to cables 61u, 61v, and 61w, respectively, at the conversion connector 62. The detection wires 110u, 110v, and 110w, as well as the rotational speed calculation devices 120A and 120B, are located outside the outer casing 8A. Cable 61u is one of the first wires, cable 61v is one of the second wires, and cable 61w is one of the third wires.

[0058] In this embodiment, the rotational speed detection system 100 includes transformers 130A and 130B. Transformers 130A and 130B are connected to the detection wire 110 between the connection point between the detection wire 110 and the cable 61 and the rotational speed calculation devices 120A and 120B. In this embodiment, transformers 130A and 130B are interposed in the detection wire 110. The first transformer 130A is connected to the detection wires 110u and 110v. The second transformer 130B is connected to the detection wires 110a and 110b, but is not limited to this configuration.

[0059] The first transformer 130A changes the voltage of the power input via the detection wires 110u and 110v, and supplies the voltage-changed power to the first rotational speed calculation unit 120A. The power input to the first transformer 130A is the power generated by the generator 7. The second transformer 130B changes the voltage of the power input from the current-voltage converter 140 via the detection wires 110a and 110b, and supplies the voltage-changed power to the second rotational speed calculation unit 120B. The power input to the second transformer 130B is the power converted by the current-voltage converter 140. Transformers 130A and 130B are located outside the outer shell 8A.

[0060] In this embodiment, a small generator is used as the generator 7 in order to miniaturize and lighten the gas turbine 1. Although the output power required for the generator 7 is high, the output current of the small generator 7 is low, so the output voltage of the generator 7 is set high. To protect the rotational speed calculation devices 120A and 120B from high voltage, the transformers 130A and 130B also function as step-down devices. Each of the transformers 130A and 130B steps down the voltage of the input power to a voltage range suitable for the rotational speed calculation devices 120A and 120B, and outputs the stepped-down power to the rotational speed calculation devices 120A and 120B. Each of the transformers 130A and 130B as step-down devices may include, for example, a voltage divider circuit including two impedance elements. Examples of impedance elements include resistors, inductors, and capacitors. For example, the rotational speed calculation devices 120A and 120B calculate the rotational speed of the generator shaft 7A from the voltage waveform after voltage division.

[0061] In this embodiment, the generator 7 generates AC power corresponding to low voltage electricity. Low voltage electricity corresponds to a voltage of 600V or less. For example, the output voltage of the generator 7 may be set within the range of 500V to 600V. For example, the voltage range suitable for the rotational speed calculation devices 120A and 120B may be set within the range of 5V to 10V.

[0062] On the other hand, if, for example, the output voltage of the generator 7 is low and falls below the voltage range suitable for the rotational speed calculation devices 120A and 120B, the transformers 130A and 130B may function as boosters. Each of the transformers 130A and 130B boosts the voltage of the input power to within the voltage range suitable for the rotational speed calculation devices 120A and 120B, and outputs the boosted power to the rotational speed calculation devices 120A and 120B. The transformers 130A and 130B, as boosters, may include a boost circuit that includes a transformer.

[0063] The amplitude of the voltage generated by the generator 7 according to this embodiment may be proportional to the rotational speed of the generator shaft 7A. Therefore, in the very low rotational speed range, the voltage generated by the generator 7 may be low and fall below the voltage range suitable for the rotational speed calculation devices 120A and 120B. In such situations, the transformers 130A and 130B may be configured to function as boosters. For example, the transformers 130A and 130B may be configured to function as both boosters and buckers depending on the situation.

[0064] An example of the rotational speed detection operation by the rotational speed calculation device 120 will be explained. As shown in Figure 1, when the mixed gas of air and fuel is burned in the combustor 5, combustion gas is generated, and the combustion gas passes backward through the gas passage G while sequentially rotating the high-pressure side turbine 6B and the low-pressure side turbine 6A. The high-pressure side turbine 6B rotates the high-pressure side compressor 4B and the generator shaft 7A via the high-pressure shaft 2B.

[0065] As shown in Figure 2, in the generator 7, the rotor 7B rotates integrally with the generator shaft 7A, generating induced current and induced voltage in the windings of the stator 7C. The generator 7 outputs AC power due to the induced current and induced voltage to the wire bundles 7Cu, 7Cv, and 7Cw. In this embodiment, since the rotor 7B includes permanent magnets, the generator 7 automatically generates AC power by the rotation of the rotor 7B, even if no power is supplied to the generator 7 for power generation. Therefore, the generator 7 generates AC power even when the rotational speed of the high-voltage shaft 2B is low, before reaching the idle speed of the gas turbine 1.

[0066] For example, if the structure of the generator 7 is such that the rotor 7B does not contain permanent magnets, then when no power is supplied to the generator 7 for power generation, even if the rotor 7B rotates, the magnetic flux passing through the windings does not change, and therefore the generator 7 does not generate power. Examples of generator structures that do not contain permanent magnets in the rotor 7B may include induction motors, wound-field motors, and reluctance motors.

[0067] As shown in Figure 3, when the generator 7 outputs AC power to the wire bundles 7Cu, 7Cv, and 7Cw, the power converter 60 full-wave rectifies the AC voltage of the input AC power to convert the AC power to DC power, and outputs the converted DC power to the motor auxiliary equipment, etc.

[0068] The first transformer 130A receives AC power rectified by the power converter 60 via detection wires 110u and 110v. The current-voltage converter 140 receives AC power rectified by the power converter 60 via detection wire 110w. An example of the voltage waveforms of the input power to the first transformer 130A and the current-voltage converter 140 is shown in Figure 5. As shown in Figure 5, the voltage waveform V2 of the AC power rectified by the power converter 60, represented by a solid line, is a waveform from which noise components have been removed from the unrectified voltage waveform V1, represented by a dashed line. The current waveform of the AC power rectified by the power converter 60 also shows a waveform from which noise components have been removed. The first transformer 130A steps down the AC power input via detection wires 110u and 110v and outputs it to the first rotational speed calculation device 120A. The current-to-voltage converter 140 converts the AC power input via the detection wire 110w into a voltage and outputs it to the second transformer 130B. The second transformer 130B steps down the input AC voltage and outputs it to the second rotational speed calculation device 120B.

[0069] The amplitude of the AC power voltage waveform input to the rotational speed calculation devices 120A and 120B is smaller than the amplitude of the voltage waveform V2 shown in Figure 5, and the period of the AC power voltage waveform input to the rotational speed calculation devices 120A and 120B is the same as the period of the voltage waveform V2 shown in Figure 5. The first rotational speed calculation device 120A calculates the rotational speed of the generator shaft 7A from the voltage waveform between the detection wires 110u and 110v. The second rotational speed calculation device 120B calculates the rotational speed of the generator shaft 7A from the voltage waveform between the detection wires 110a and 110b. Both rotational speed calculation devices 120A and 120B may perform the rotational speed calculation, and the second rotational speed calculation device 120B may perform the rotational speed calculation if the first rotational speed calculation device 120A cannot obtain a result for calculating the rotational speed. If the second rotational speed calculation device 120B is unable to obtain a rotational speed calculation result, the first rotational speed calculation device 120A may perform the rotational speed calculation. Regardless of the configuration of the rotational speed calculation devices 120A and 120B, even if an abnormality occurs in any of the detection wires 110u, 110v, and 110w, the rotational speed calculation result of the generator shaft 7A can be obtained.

[0070] While exemplary embodiments of the present disclosure have been described above, the disclosure is not limited to these embodiments. That is, various modifications and improvements are possible within the scope of the disclosure. For example, embodiments that have been modified in various ways, and forms constructed by combining components from different embodiments, are also included within the scope of the disclosure.

[0071] For example, in the gas turbine 1 according to this embodiment, the rotational speed calculation device 120 includes rotational speed calculation devices 120A and 120B as independent devices, but may also include them as an integrated device. Either or both of the rotational speed calculation devices 120A and 120B may be included in the control device 200 as part of the device or part of the function of the control device 200.

[0072] In the gas turbine 1 according to this embodiment, the power converter 60 is configured to perform full-wave rectification by including a full-wave rectifier circuit, but the configuration of the power converter 60 is not limited to this. For example, the power converter 60 may be configured to perform full-wave rectification by including a PWM circuit. In this case, the power converter 60 can perform rectification similar to full-wave rectification by processing the signal without switching the PWM circuit.

[0073] The rotational speed calculation device 120 according to this embodiment is electrically connected to three main power lines E via three detection wires 110 and calculates the rotational speed of the generator shaft 7A based on the behavior of the voltage or current of the three main power lines E, but the configuration of the rotational speed calculation device 120 is not limited to this. The rotational speed calculation device 120 may be electrically connected to one main power line E via one detection wire 110 and calculate the rotational speed of the generator shaft 7A based on the behavior of the current of one main power line E. The rotational speed calculation device 120 may be electrically connected to two main power lines E via two detection wires 110 and calculate the rotational speed of the generator shaft 7A based on the behavior of the voltage between the two main power lines E. If the number of main power lines E of the generator 7 is four or more, the rotational speed calculation device 120 may be electrically connected to four or more main power lines E via four or more detection wires 110 and calculate the rotational speed of the generator shaft 7A based on the behavior of the voltage or current of four or more main power lines E.

[0074] In the gas turbine 1 according to this embodiment, the first rotational speed calculation device 120A is electrically connected to the U-phase detection wire 110u and the V-phase detection wire 110v, and the second rotational speed calculation device 120B is electrically connected to the W-phase detection wire 110w. However, the combination of detection wires to which the rotational speed calculation devices 120A and 120B are connected is not limited to the above. The first rotational speed calculation device 120A may be connected to the detection wires 110u and 110w, and the second rotational speed calculation device 120B may be electrically connected to the detection wire 110v. The first rotational speed calculation device 120A may be connected to the detection wires 110v and 110w, and the second rotational speed calculation device 120B may be electrically connected to the detection wire 110u.

[0075] In the gas turbine 1 according to this embodiment, the detection wire 110, the rotational speed calculation device 120, the transformers 130A and 130B, and the current-voltage converter 140 are located outside the outer shell 8A. However, at least a portion of the detection wire 110, the rotational speed calculation device 120, the transformers 130A and 130B, and the current-voltage converter 140 may be located inside the outer shell 8A. For example, the connection between the detection wire 110 and the main wire E may be located inside the outer shell 8A. In this case, the detection wire 110 may be arranged along the same route as the main wire E inside the outer shell 8A. As a result, the detection wire 110 is protected by the bearing housing 30A and the strut housing 11, just like the main wire E.

[0076] The strut through which the main power line E and the detection power line 110 pass is not limited to strut 11d of the strut housing 11 located between the generator 7 and the high-pressure side compressor 4B. For example, the strut through which the main power line E and the detection power line 110 pass may be a strut other than strut 11d. The gas turbine 1 may include such struts at a location between the low-pressure side compressor 4A and the generator 7, at the location of the generator 7, at the location of the second bearing housing 30B, or in front of or behind the second bearing housing 30B.

[0077] The gas turbine 1 according to this embodiment includes a generator connector 7F, a first external connector 51, a relay connector 53, a second external connector 54, and a conversion connector 62 in the middle of the main power line E, but the configuration of the main power line E is not limited thereto, and one or more of the generator connector 7F, the first external connector 51, the relay connector 53, the second external connector 54, and the conversion connector 62 may be omitted.

[0078] In the gas turbine 1 according to this embodiment, the generator 7 has an inner rotor type structure in which the rotor 7B is located inside the stator 7C, but it may also have an outer rotor type structure in which the rotor surrounds the stator. Even in such a structure, the rotor including permanent magnets can be connected to rotate integrally with the hollow generator shaft 7A.

[0079] The gas turbine 1 according to this embodiment is a twin-shaft gas turbine in which the rotating shaft 2 includes two shafts, a low-pressure shaft 2A and a high-pressure shaft 2B. However, it may also be a single-shaft gas turbine in which the rotating shaft 2 includes only one shaft. In this case, the single-shaft gas turbine may have a structure in which a part or all of the inner circumferential surface of the generator shaft 7A engages with a part of the outer circumferential surface of the rotating shaft 2, or a structure in which a part or all of the outer circumferential surface of the generator shaft 7A engages with a part of the inner circumferential surface of the rotating shaft 2. Alternatively, the generator shaft 7A and the rotating shaft 2 may be a single continuous shaft.

[0080] The structure of the gas turbine 1 according to this embodiment is such that the front end 2Ba of the high-pressure shaft 2B is inserted into the internal space of the rear end 7Ab of the generator shaft 7A, but is not limited thereto. For example, the gas turbine 1 may have a structure in which the rear end 7Ab of the generator shaft 7A is inserted into the internal space of the front end 2Ba of the high-pressure shaft 2B. For example, the high-pressure shaft 2B and the generator shaft 7A may be a single continuous shaft. The components of the generator 7 may then be assembled to this shaft.

[0081] Examples of each aspect of the technology of the present disclosure are as follows: A gas turbine according to the first aspect of the present disclosure includes an AC generator including a rotor, a rotating shaft connected to rotate integrally with the rotor, a rotor that rotates integrally with the rotating shaft and includes permanent magnets, and a stator; a main power line connected to the AC generator through which the current generated by the AC generator flows; a detection power line connected to the main power line; and a rotational speed calculation device connected to the detection power line, which calculates the rotational speed of the rotating shaft based on the behavior of the voltage or current generated by the AC generator.

[0082] According to the first embodiment, the rotational speed of the rotor blades can be detected by the rotational speed of the rotor of the AC generator. The rotational speed of the rotor of the AC generator is related to the frequency of the power generated by the AC generator. Therefore, the rotational speed of the rotor blades can be detected based on the behavior of the voltage or current of the power generated by the AC generator. Thus, the AC generator also serves as a structure for detecting the rotational speed of the rotor blades. Furthermore, since the rotational speed calculation device is connected to the main power line via a detection wire, there is a high degree of freedom in the placement of the rotational speed calculation device. Therefore, the rotational speed calculation device can be placed in a position that does not affect the structure of the gas turbine. Thus, the increase in size of the gas turbine due to the structure for obtaining the rotational speed of the gas turbine is prevented.

[0083] A gas turbine according to a second aspect of the present disclosure may include a housing that accommodates the rotor blades, the rotating shaft, and the AC generator, in addition to the gas turbine according to the first aspect, and the rotational speed calculation device may be located outside the housing.

[0084] According to the second embodiment, since the rotational speed calculation device is located on the outside of the housing, it is possible to prevent the gas turbine from becoming larger due to the rotational speed calculation device.

[0085] A gas turbine according to a third aspect of this disclosure may include a power converter connected to the main power line and performing full-wave rectification, in the gas turbine according to the first or second aspect, wherein the detection wire may be configured to be connected to the main power line between the AC generator and the power converter.

[0086] According to the third embodiment, the power converter rectifies both the positive and negative waves of the alternating current output from the AC generator. The behavior of the current or voltage rectified by the power converter makes frequency detection easy and accurate. Therefore, it is possible to obtain the rotational speed of the rotor blades accurately.

[0087] A gas turbine according to a fourth aspect of this disclosure may be configured such that, in the gas turbine according to a third aspect, it includes a housing that accommodates the rotor blades, the rotor shaft, and the AC generator, and the power converter is located outside the housing.

[0088] According to the fourth embodiment, since the power converter is located on the outside of the housing, it is possible to prevent the gas turbine from becoming larger due to the power converter.

[0089] A gas turbine according to a fifth aspect of the present disclosure may be a gas turbine according to any one of the first to fourth aspects, wherein the main power line includes a first power line, a second power line, and a third power line having different phases from each other, the detection power line is connected to the first power line, the second power line, and the third power line, and the rotational speed calculation device may be configured to calculate the rotational speed of the rotating shaft based on the behavior of the voltage between the first power line and the second power line generated by the AC generator, or the behavior of the current in the third power line generated by the AC generator.

[0090] According to the fifth embodiment, the rotational speed calculation device can calculate the rotational speed of the rotating shaft from either the voltage between the first and second wires or the current in the third wire. For example, even if the voltage between the first and second wires cannot be detected, the rotational speed calculation device can calculate the rotational speed of the rotating shaft from the behavior of the current in the third wire, and even if the current in the third wire cannot be detected, it can calculate the rotational speed of the rotating shaft from the behavior of the voltage between the first and second wires. Therefore, redundancy in the rotational speed calculation process is possible.

[0091] A gas turbine according to the sixth aspect of this disclosure may be configured in any one of the first to fifth aspects to include a transformer connected to the detection wire between the connection portion of the main wire and the detection wire and the rotational speed calculation device, the transformer which transforms the power generated by the AC generator and supplies it to the rotational speed calculation device.

[0092] According to the sixth embodiment, the output voltage of the AC generator can be changed without improving the capabilities of the rotational speed calculation device. Since the voltage of a permanent magnet AC generator is proportional to the rotational speed, for example, in the very low rotational speed range, the output voltage of the AC generator may be low. By boosting the output voltage with a transformer, the rotational speed calculation device can calculate the rotational speed based on the behavior of the output voltage. On the other hand, in the high rotational speed range, the output voltage of the AC generator may be high. By lowering the output voltage with a transformer, it is possible to prevent failure of the rotational speed calculation device due to overvoltage.

[0093] A gas turbine according to a seventh aspect of this disclosure may be configured such that, in the gas turbine according to a sixth aspect, it includes a housing that accommodates the rotor blades, the rotor shaft, and the AC generator, and the transformer is located outside the housing.

[0094] According to the seventh embodiment, since the transformer is located on the outside of the housing, it is possible to prevent the gas turbine from becoming larger due to the transformer.

[0095] A gas turbine according to the eighth aspect of this disclosure may be configured such that, in a gas turbine according to any one of the first to seventh aspects, the permanent magnet is a cobalt magnet or a neodymium magnet.

[0096] In the eighth embodiment, neodymium magnets generate the strongest magnetic force among existing permanent magnets, and therefore can generate sufficient magnetic force even in high-temperature environments. Cobalt magnets have high heat resistance and thermal stability, and therefore can generate sufficient magnetic force even in high-temperature environments. Thus, the heat resistance of AC generators can be improved.

[0097] A gas turbine according to the ninth aspect of this disclosure is a gas turbine according to any one of the first to eighth aspects, comprising: an air passage through which air introduced into the gas turbine flows; a low-pressure compressor located in the air passage and pressurizing the air flowing through the air passage; a high-pressure compressor located downstream of the low-pressure compressor in the air passage and pressurizing the air flowing through the air passage; a combustor for burning a mixture of air and fuel supplied by the high-pressure compressor; a gas passage through which combustion gas discharged from the combustor flows; and a gas passage located in the gas passage and flowing through the gas passage The system may be configured to include a high-pressure side turbine rotated by a fuel gas, a low-pressure side turbine located downstream of the high-pressure side turbine in the gas flow path and rotated by the fuel gas flowing through the gas flow path, a cylindrical high-pressure shaft connecting the high-pressure side compressor and the high-pressure side turbine to rotate together, and a low-pressure shaft inserted relatively rotatably into the high-pressure shaft and connecting the low-pressure side compressor and the low-pressure side turbine to rotate together, wherein the rotor blades are the high-pressure side compressor or the high-pressure side turbine, and the rotating shaft is the high-pressure shaft.

[0098] According to the ninth embodiment, the rotor of the AC generator is rotated by the high-pressure side turbine. The rotational speed of the high-pressure side turbine is higher than that of the low-pressure side turbine. The temperature of the high-pressure side turbine is higher than that of the low-pressure side turbine. When a rotation sensor is installed to detect the rotational speed of the high-speed and high-temperature high-pressure side turbine, the gas turbine may become larger due to the need for a larger structure for the rotation sensor, which requires heat resistance, and the constraints on the position of the rotation sensor. Since the rotational speed of the high-pressure side turbine is detected via the AC generator, the gas turbine does not need to be made larger.

[0099] A gas turbine according to a tenth aspect of the present disclosure may be configured such that, in the gas turbine according to a ninth aspect, the high-pressure shaft, the high-pressure side compressor, and the high-pressure side turbine are located between the low-pressure side compressor and the low-pressure side turbine in the longitudinal direction which is the axial direction of the gas turbine, the high-pressure side turbine is located between the high-pressure side compressor and the low-pressure side turbine in the longitudinal direction, and the rotor is located between the low-pressure side compressor and the high-pressure side compressor in the longitudinal direction.

[0100] According to the tenth embodiment, the low-pressure compressor, rotor, high-pressure compressor, high-pressure turbine, and low-pressure turbine are arranged axially in this order. This makes it possible to reduce the size of the gas turbine in the axial direction.

[0101] The functions of the elements disclosed herein may be implemented using one or more circuits or processing circuits, including general-purpose processors, special-purpose processors, integrated circuits, ASICs, FPGAs, and / or conventional circuits. The functions of the elements disclosed herein may be implemented using one or more circuits or processing circuits, including a combination of general-purpose processors, special-purpose processors, integrated circuits, ASICs, FPGAs, and conventional circuits. One or more circuits or processing circuits may be programmed using one or more programs stored together or individually in one or more memories, or otherwise configured to perform the disclosed functions. A processor is considered a processing circuit or circuit because it includes transistors and other circuits. A processor may be a programmed processor that executes programs stored in memory. In this disclosure, a circuit, unit, or means is hardware that performs the enumerated functions alone or in combination with each other, or hardware programmed to perform the enumerated functions alone or in combination with each other. Hardware may be any hardware disclosed herein that is programmed or configured to perform the enumerated functions. Computer programs, including computer instructions, are stored in memory. Computer instructions provide logic and routines that enable hardware to perform the methods disclosed herein. Hardware includes, for example, processing circuits or circuits. Computer programs may be implemented in known formats on computer-readable storage media, computer program products, memory devices, recording media such as CD-ROMs or DVDs, and / or in the memory of FPGAs or ASICs.

[0102] All ordinal numbers, quantities, and other figures used herein are illustrative to illustrate the technology of this disclosure, and this disclosure is not limited to such illustrative figures. The connections between components are illustrative to illustrate the technology of this disclosure, and the connections that realize the functions of this disclosure are not limited to these.

[0103] This disclosure can be implemented in various ways without departing from the scope of its essential features, and the scope of this disclosure is defined more by the appended claims than by the description in the specification; therefore, exemplary embodiments and modifications are illustrative and not limiting. All modifications within the claims and their scope, or equivalents within the claims and their scope, are intended to be encompassed by the claims. [Explanation of symbols]

[0104] 1 Gas turbine, 2 Rotating shaft, 2A Low-pressure shaft, 2B High-pressure shaft, 4 Compressor, 4A Low-pressure compressor, 4B High-pressure compressor, 5 Combustor, 6 Turbine, 6A Low-pressure turbine, 6B High-pressure turbine, 7 Generator, 7A Generator shaft, 7B Rotor, 7C Stator, 7Cc, 7Cu, 7Cv, 7Cw Wire bundle (main lines), 8 Casing, 52, 52u, 52v, 52w Cable (main lines), 60 Power converter, 61, 61u, 61v, 61w Cable (main lines), 110, 110u, 110v, 110w Detection wire, 120, 120A, 120B Rotation speed calculation device, 130 Transformer, E Main lines, G Gas flow path (air flow path).

Claims

1. A gas turbine, Rotary blades and A rotating shaft connected to the aforementioned rotor blade so as to rotate integrally with it, An AC generator comprising a rotor that rotates integrally with the aforementioned rotating shaft and includes a permanent magnet, and a stator, An outer housing housing the rotor blade, the rotating shaft, and the AC generator, An inner housing located inside the outer housing and containing the AC generator on the inside, the inner housing defining an air passage on the outside through which air introduced to the gas turbine flows, A strut connecting the outer housing and the inner housing, A main power line connected to the AC generator, extending through the strut to the outside of the outer housing, through which the current generated by the AC generator flows, comprising a first wire, a second wire, and a third wire, each having different phases from the other. A power converter connected to the first, second, and third electric wires, which performs full-wave rectification, A detection wire connected to the first wire, the second wire, and the third wire inside the outer housing and between the AC generator and the power converter, the detection wire extending through the strut, A rotational speed calculation device located outside the outer housing and connected to the detection wire, configured to perform a first calculation that calculates the rotational speed of the rotating shaft based on the behavior of the line voltage between the first wire and the second wire generated by the AC generator, and a second calculation that calculates the rotational speed of the rotating shaft based on the behavior of the current in the third wire generated by the AC generator, A transformer connected to the detection wire between the connection portion between the first and second wires and the detection wire and the rotational speed calculation device, the transformer transforms the power generated by the AC generator and supplies it to the rotational speed calculation device, The rotational speed calculation device is configured to calculate, in the first calculation, the number of zero-crossings per unit time in the voltage waveform of the line voltage where the voltage value becomes 0, and to calculate the rotational speed of the rotating shaft based on the number of occurrences, or The rotational speed calculation device includes a V / F (voltage / frequency) converter circuit that takes the voltage signal of the line voltage as an input signal and the frequency signal of the voltage signal as an output signal, and in the first calculation, it is configured to calculate the rotational speed of the rotating shaft based on the frequency signal output by the V / F converter circuit. Gas turbine.

2. The power converter is located on the outside of the outer housing, The gas turbine according to claim 1.

3. The transformer is located on the outside of the outer housing, The gas turbine according to claim 1.

4. The aforementioned permanent magnet is a cobalt magnet or a neodymium magnet. The gas turbine according to claim 1.

5. The air passage and A low-pressure side compressor located in the aforementioned air passage and pressurizing the air flowing through the aforementioned air passage, A high-pressure compressor located downstream of the low-pressure compressor in the aforementioned air passage and pressurizing the air flowing through the air passage, A combustor that burns the mixture of air and fuel supplied by the high-pressure compressor, A gas passage through which combustion gas discharged from the aforementioned combustor flows, A high-pressure side turbine located in the aforementioned gas flow path and rotated by the fuel gas flowing through the aforementioned gas flow path, A low-pressure side turbine is located downstream of the high-pressure side turbine in the gas flow path and is rotated by the fuel gas flowing through the gas flow path, A cylindrical high-pressure shaft connects the high-pressure side compressor and the high-pressure side turbine so that they rotate as a single unit, It includes a low-pressure shaft that is rotatably inserted into the high-pressure shaft and connects the low-pressure side compressor and the low-pressure side turbine so as to rotate together, The rotor blade is the high-pressure side compressor or the high-pressure side turbine, The aforementioned rotating shaft is the high-pressure shaft. The gas turbine according to claim 1.

6. The high-pressure shaft, the high-pressure side compressor, and the high-pressure side turbine are located between the low-pressure side compressor and the low-pressure side turbine in the longitudinal direction which is the axial direction of the gas turbine. The high-pressure side turbine is located between the high-pressure side compressor and the low-pressure side turbine in the longitudinal direction. The rotor is located between the low-pressure compressor and the high-pressure compressor in the front-rear direction. The gas turbine according to claim 5.

7. The rotational speed calculation device is configured to obtain the rotational speed of the rotating shaft by performing both the first calculation and the second calculation, or to obtain the rotational speed of the rotating shaft by selectively performing either the first calculation or the second calculation. A gas turbine according to any one of claims 1 to 6.

Images