Method and module for detecting the state of a coupling device, and associated turbine engine and aircraft

Abstract

This method for controlling the operation of a coupling device (18) for a turbine engine (4) of an aircraft (2) comprises the steps of: - a first comparison (48) of the speed of rotation of an electric machine (16) which is determined with a profile of evolution with respect to time, the first comparison (48) being implemented to determine an operating deviation; - a second comparison (50) of the operating deviation with a detection threshold; and - according to the result of the second comparison step (50), an identification of the existence or absence of a failure (52) of the coupling device (18); the second comparison step (50) comprising the determination of the value of the detection threshold from at least one control parameter (P), the operating deviation and the rotational speed of the electric machine (16).

Description

[0001] DESCRIPTION

[0002] TITLE: Method and module for detecting the state of a coupling device, turbomachine and associated aircraft

[0003] Technical field

[0004] The invention relates to the detection of the operating state of a coupling device connecting two shafts together.

[0005] The invention relates more particularly to a module for controlling the operation of the coupling device, a turbomachine comprising a coupling device and such a module, an aircraft comprising such a turbomachine and a method for controlling the operation of the coupling device.

[0006] Previous techniques

[0007] An aircraft is generally equipped with a turbomachine comprising at least one rotating shaft, at least one gas turbine, at least one compressor and a combustion chamber.

[0008] The turbomachine may include an electric machine, for example with permanent magnets.

[0009] As long as the rotor of the electric machine turns, the magnets generate an electromotive force.

[0010] In a short circuit, the current generated by the electromotive force causes the loop in which the current flows to heat up, which is likely to cause a fire on board the aircraft.

[0011] It is known to add a coupling device connecting a rotor shaft of the electric machine to a drive shaft of the turbomachine to separate the drive shaft from the rotor shaft of the electric machine.

[0012] In order to ensure a high level of availability and operational reliability of the coupling device, it is necessary to periodically check its operation to ensure that upon a disconnection command, the coupling device disconnects the drive shaft and the rotor shaft. In particular, upon a disconnection instruction following the detection of a fault in the electrical machine, it is necessary to have confirmation of the disconnection of the coupling device. It is therefore necessary to have an adaptive verification method for the operating state of the coupling device.

[0013] Statement of the invention

[0014] The present invention aims to overcome all or part of these drawbacks.

[0015] The present invention relates to a method for controlling the operation of a coupling device for an aircraft turbomachine, the turbomachine comprising a rotary shaft and an electric machine, the coupling device being configured to connect a rotor shaft of the electric machine to the rotary shaft and having two operating states, a coupled state so as to secure the rotor shaft and the rotary shaft and a decoupled state so as to separate the rotor shaft and the rotary shaft, the method comprising the following steps: determining a control state of the coupling device; determining the rotational speed of the electric machine; determining the rotational speed of the rotary shaft;a first comparison of the rotational speed of the determined electrical machine with a time evolution profile of the rotational speed of the electrical machine determined from the rotational speed of the rotating shaft and the control state of the coupling device, the first comparison being implemented to determine an operating deviation; a second comparison of the operating deviation with a detection threshold; and according to the result of the second comparison step, an identification of the existence or absence of a failure of the coupling device; the second comparison step comprising the determination of the value of the detection threshold from at least one control parameter, the operating deviation and the rotational speed of the electrical machine.;

[0016] Determining the value of the detection threshold as a function of the control parameter, the operating deviation and the rotation speed of the electric machine makes it possible to take into account the operating conditions of the turbomachine in order to improve the detection of a failure of the coupling device.

[0017] Advantageously, the control parameter is chosen from the outside temperature, the altitude of the aircraft and a parameter representative of a type of failure of the electrical machine.

[0018] Optionally, the first comparison step includes a preliminary step of determining a chart of time evolution profiles of the rotation speed of the electrical machine as a function of the rotation speed of the rotating shaft and the control state of the coupling device.

[0019] Advantageously, the second comparison step comprises the calculation of the gradient of the operating deviation and a step of calculating the gradient of the time evolution profile prior to the second comparison step, the value of the detection threshold being determined from the control parameter, the gradient of the operating deviation, and the gradient of the rotation speed of the determined electrical machine.

[0020] Advantageously, the method comprises a step of delaying the result of the second comparison step.

[0021] Optionally, the method comprises, prior to the step of determining the rotation speed of the electric machine, a control of the electric machine in motor mode when the turbomachine is stopped.

[0022] Optionally, the method comprises a rotational locking of the rotary shaft when the electric machine is operating in motor mode. The present invention also relates to a module for controlling the operation of a coupling device for an aircraft turbomachine, the turbomachine comprising a rotary shaft and an electric machine, the coupling device being configured to connect a rotor shaft of the electric machine to the rotary shaft and having two operating states, a coupled state so as to secure the rotor shaft and the rotary shaft and a decoupled state so as to separate the rotor shaft and the rotary shaft, the module comprising: first determination means configured to determine a control state of the coupling device;second determination means configured to determine the rotational speed of the electrical machine, third determination means configured to determine the rotational speed of the rotating shaft; first comparison means configured to compare the rotational speed of the electrical machine with a time evolution profile of the rotational speed of the electrical machine determined from the rotational speed of the rotating shaft and the control state of the coupling device, the first comparison means being configured to determine an operating deviation; second comparison means configured to compare the operating deviation with a detection threshold; and means for determining a failure configured to identify the existence of a failure or an absence of failure of the coupling device according to the result delivered by the second comparison means;the second comparison means being further configured to determine the value of the detection threshold from at least one control parameter, the operating deviation and the rotation speed of the electrical machine.;

[0023] The present invention also relates to a turbomachine for an aircraft comprising a rotary shaft, an electric machine, and a coupling device configured to connect a rotor shaft of the electric machine to the rotary shaft and having two operating states, a coupled state so as to secure the rotor shaft and the rotary shaft and a decoupled state so as to separate the rotor shaft and the rotary shaft, the turbomachine comprising a control module as defined previously.

[0024] The present invention finally relates to an aircraft comprising a turbomachine as defined above.

[0025] Brief description of the drawings

[0026] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example and made with reference to the appended drawings in which:

[0027] [Fig 1] schematically illustrates an aircraft according to the invention;

[0028] [Fig 2] schematically illustrates a control module according to the invention; and

[0029] [Fig 3] schematically illustrates a method for controlling the operation of a coupling device of an aircraft turbomachine according to the invention.

[0030] Detailed description

[0031] Figure 1 schematically represents an aircraft 2 comprising a turbomachine 4, the aircraft 2 being for example an airplane, a helicopter or an airplane with vertical takeoff and landing.

[0032] The turbomachine 4 comprises at least one rotating shaft, here a rotating shaft 6 on which are mounted a fan 8, a compressor 10, a combustion chamber 12 and a turbine 14.

[0033] The turbomachine 4 comprises an electric machine 16 and a coupling device 18 connecting the rotor shaft of the electric machine 16 to the rotating shaft 6, for example via a gearbox having a predetermined transmission ratio. The coupling device 18 may, however, directly connect the rotor shaft of the electric machine 16 to the rotating shaft 6.

[0034] The electrical machine 16 comprises, for example, a permanent magnet synchronous machine associated with a power electronics converter or an electromagnet machine. The electrical machine 16 comprises a rotor shaft (not shown).

[0035] Alternatively, the electric machine 16 has a wound rotor.

[0036] The coupling device 18 comprises two operating states, namely a so-called “coupled” state in which the rotor shaft and the rotary shaft 6 are secured and a so-called “decoupled” state in which the rotor shaft and the rotary shaft 6 are detached.

[0037] The turbomachine 4 further comprises a control device 20 capable of controlling the coupling device 18 so that the coupling device 18 is in a coupled state or an uncoupled state.

[0038] The electrical machine 16 comprises a diagnostic sensor 22. For example, the diagnostic sensor 22 may be a temperature sensor capable of detecting overheating of the electrical machine 16, a force sensor capable of detecting a failure of bearings of the electrical machine 16, an electrical sensor capable of detecting a short circuit of the electrical machine 16, a pressure sensor or an oil level sensor.

[0039] Alternatively, the diagnostic sensor 22 can be considered as a set of different sensors chosen from the temperature sensor, the force sensor, the pressure sensor, the oil level sensor and the electrical sensor for example.

[0040] Furthermore, the turbomachine 4 comprises a temperature sensor 24 capable of measuring the temperature outside the turbomachine 4 and an altitude sensor 26 capable of measuring the altitude at which the turbomachine 4 is located.

[0041] The coupling device 18 is controlled by a control module 28.

[0042] This control module 28 comprises, as illustrated in FIG. 2, first means 30 for determining the control state of the coupling device 18, second means 32 for determining the rotation speed of the electrical machine 16, third means 34 for determining the rotation speed of the rotary shaft 6.

[0043] The first determination means 30 are for example electronically connected to the control device 20.

[0044] The second determination means 32 comprise, for example, a rotation speed sensor capable of measuring the rotation speed of the rotor shaft of the electrical machine 16.

[0045] The third determination means 34 comprise, for example, a rotation speed sensor capable of measuring the rotation speed of the rotating shaft 6.

[0046] The control module 28 further comprises first comparison means 36 configured to compare the rotation speed of the electrical machine 16 with a time evolution profile of the rotation speed of the electrical machine 16 determined from the rotation speed of the rotating shaft 6 and the control state of the coupling device 18. The first comparison means 36 are thus configured to determine an operating deviation.

[0047] These first comparison means 36 may comprise a software architecture intended to implement a comparison algorithm. Such first comparison means 36 may be in the form of logic circuits forming a comparator for example.

[0048] Second comparison means 38, for example in the form of a comparator or a software architecture integrating a second comparison algorithm, ensure the comparison between the operating deviation and a detection threshold.

[0049] The second comparison means 38 determine the value of the detection threshold from at least one control parameter P, the operating deviation and the rotation speed of the electrical machine 16.

[0050] The control module 28 comprises means for determining a failure 40, for example software means, configured to identify the existence or absence of a failure of the coupling device 18 according to the result delivered by the second comparison means 38. They are electronically connected to a warning light or to an alarm system, which may be audible, of the aircraft 2 to warn an operator of the failure. Optionally, the means for determining a failure 40 are capable of stopping the turbomachine 4 in the event of detection of a failure in the change of state of the coupling device 18, the electrical machine 16 no longer rotating when the turbomachine 4 is stopped.

[0051] Figure 3 schematically represents a method for controlling the operation of the coupling device 18.

[0052] It is assumed that the combustion chamber 12 generates hot gases driving the turbine 14.

[0053] During a step 42 of determining the control state of the coupling device 18, the first determination means 30 and the control device 20 determine a control state of the coupling device 18. The control state of the coupling device 18 is delivered in the form of a control instruction in the coupled state or in the decoupled state of the coupling device 18.

[0054] During a step 44 of determining the rotation speed of the electrical machine 16, a rotation speed sensor of the second determination means 32 measures the rotation speed of the rotor shaft of the electrical machine 16. The rotation speed of the electrical machine 16 is for example recorded in a memory of the second determination means 32.

[0055] In the following step 46, the rotational speed of the rotary shaft 6 is determined. A rotational speed sensor of the third determining means 34 measures the rotational speed of the rotary shaft 6. The measured rotational speed of the rotary shaft 6 is, for example, recorded in a memory of the third determining means 34.

[0056] Steps 42, 44 and 46 can be performed simultaneously or successively.

[0057] The first comparison means 36 then compare the rotation speed of the electrical machine 16 with a time evolution profile of the rotation speed of the electrical machine 16 determined from the rotation speed of the rotating shaft 6 and the control state of the coupling device 18 to determine an operating deviation (step 48).

[0058] The operating deviation is for example equal to the difference between the rotation speed of the electrical machine 16 and the time evolution profile. This difference can be an instantaneous difference or a sum of the difference between the determined rotation speed of the electrical machine 16 and the time evolution profile over a predetermined duration.

[0059] The time evolution profile comprises the evolution of the rotational speed of the rotating shaft 6 when the coupling device 18 is in a coupled state or the evolution of the rotational speed of the rotating shaft 6 when the coupling device 18 is in a decoupled state. It is obtained for example from a model of the coupling device 18 operating reliably or for example from a technical data sheet of the electric machine 16.

[0060] The time evolution profile is extracted from an abacus of time evolution profiles of the rotation speed of the electric machine 16.

[0061] The abacus is determined prior to the first comparison step as a function of the rotational speed of the rotating shaft 6 and the control state of the coupling device 18.

[0062] The time evolution profile chart allows you to quickly determine the time evolution profile used during the first comparison step 48.

[0063] In the following step 50, the second comparison means 38 compare the operating deviation with a detection threshold.

[0064] The detection threshold is variable and is determined from a control parameter P, the operating deviation and the rotation speed of the electrical machine 16.

[0065] The control parameter P comprises, for example, the temperature outside the aircraft 2 measured by the temperature sensor 24, the altitude of the aircraft 2 measured by the altitude sensor 26. The temperature outside the aircraft 2 makes it possible to determine the viscosity of the oil in the electrical machine 16 and / or the viscosity of the oil in the turbomachine 4.

[0066] When the viscosity of the cooling oil of the electric machine 16 is high, the electric machine 16 has a greater inertia. When the viscosity of the oil of the turbomachine 4 is high and the coupling device 18 is in a coupled state, the electric machine 16 has a greater inertia.

[0067] Taking into account the altitude of the aircraft 2 makes it possible to adjust the start-up time of the turbomachine 4.

[0068] The higher the altitude of aircraft 2, the longer the start-up time of turbomachine 4, for example 60 seconds at sea level to 120 seconds at high altitude.

[0069] The control parameter P may comprise a parameter representative of a type of failure of the electrical machine 16.

[0070] For example, when overheating of the electrical machine 16 is detected by the diagnostic sensor 22, the second comparison means 38 modify the threshold value to take into account the change in behavior of the electrical machine 16 as a result of the overheating. When the diagnostic sensor 22 detects a defective bearing of the electrical machine 16, the second comparison means 38 modify the threshold value to take into account the change in behavior of the electrical machine 16 as a result of the failure of the bearing. When the diagnostic sensor 22 detects a short circuit in the electrical machine 16, the second comparison means 38 modify the threshold value to take into account the change in behavior of the electrical machine 16.When the diagnostic sensor 22 detects an abnormal pressure or an abnormal oil level, the second comparison means 38 modify the threshold value to take into account the change in behavior of the electrical machine 16.

[0071] Of course, the parameter P can comprise several quantities among the outside temperature of the aircraft 2, the altitude of the aircraft 2 and the parameter representative of a type of failure. As a variant, the method comprises the calculation of the gradient (V) of the operating deviation and a step of calculating the gradient of the time evolution profile prior to the second comparison step 50, the value of the detection threshold being determined from the control parameter P, the gradient of the operating deviation, and the gradient of the time evolution profile of the rotation speed of the electrical machine 16.

[0072] The use of gradients allows rapid detection of behavioral deviation.

[0073] Depending on the result of step 50, a failure of the coupling device 18 can be detected (step 52). If, for example, the operating deviation is greater than the variable detection threshold, then the coupling device 18 is considered to be faulty. If the operating deviation is less than the detection threshold, then the coupling device 18 is considered to be functional.

[0074] During a time delay step 54, the result delivered by the second comparison means 38 is stored in a memory for a predetermined duration and steps 42, 44, 46, 48 and 50 are repeated, then the result delivered by the second comparison means 38 is compared with the result stored in the memory. If the two results are identical and representative of a failure, the failure determination means 40 signal the failure. Otherwise, the failure determination means 40 signal the absence of failure.

[0075] The control method is for example implemented following a change of state of the coupling device 18 to decouple the electrical machine 16 following a breakdown of the electrical machine 16, or when implementing an operating test of the coupling device 18 or to ensure that the coupling device 18 is still in the operating state controlled by the control device 20.

[0076] It is now assumed that the turbomachine 4 is stopped, the aircraft 2 being for example on the ground.

[0077] The method begins with a step 56 of controlling the electric machine 16 in motor mode so that the electric machine 16 uses electrical power to generate mechanical rotational power.

[0078] Preferably, the control device 20 drives the electric machine 16 in motor mode so that the electric machine 16 generates sufficient mechanical power to drive the rotor shaft of the electric machine 16 in rotation, but insufficient to drive the rotary shaft 6 in rotation.

[0079] Then we carry out steps 42, 44 and 46 described previously.

[0080] During the first comparison step 48, the rotational speed of the rotating shaft 6 is zero. The time evolution profile includes the rotational speed of the decoupled electrical machine 16.

[0081] The method continues at steps 50, 52, 54 as previously described.

[0082] When the control device 20 controls the electric machine 16 in motor mode so that the electric machine 16 generates sufficient mechanical power to drive the rotor shaft of the electric machine 16 in rotation and to drive the rotary shaft 6 in rotation, during a step 58 of blocking the rotation of the rotary shaft 6, a propeller brake is for example activated to prevent the rotation of the rotary shaft 6.

[0083] Then the process continues to step 56.

[0084] The blocking step 58 also makes it possible to prevent a misjudgment of the operating state of the coupling device 18 when the rotating shaft 6 is rotated by the wind “windmilling” in English.

[0085] Adjusting the value of the detection threshold according to the control parameter P, the operating deviation and the rotation speed of the electric machine 16 makes it possible to take into account the conditions of use of the turbomachine 4 in order to improve the detection of a failure of the coupling device 18.

Claims

CLAIMS 1. Method for controlling the operation of a coupling device (18) for a turbomachine (4) of an aircraft (2), the turbomachine (4) comprising a rotary shaft (6) and an electric machine (16), the coupling device (18) being configured to connect a rotor shaft of the electric machine (16) to the rotary shaft (6) and having two operating states, a coupled state so as to secure the rotor shaft and the rotary shaft (6) and a decoupled state so as to separate the rotor shaft and the rotary shaft (6), the method comprising the steps of: determining a control state of the coupling device (18) delivered in the form of a control instruction in the coupled state or in the decoupled state of the coupling device (18); determining the rotational speed of the electric machine (16); determining the rotational speed of the rotary shaft (6);a first comparison (48) of the rotational speed of the electrical machine (16) determined with a time evolution profile of the rotational speed of the electrical machine (16) determined from the rotational speed of the rotating shaft (6) and the control state of the coupling device (18), the first comparison (48) being implemented to determine an operating deviation; - a second comparison (50) of the operating deviation with a detection threshold; and according to the result of the second comparison step (50), an identification of the existence or absence of a failure (52) of the coupling device (18); characterized in that the second comparison step (50) comprises determining the value of the detection threshold at from at least one control parameter (P), the operating deviation and the rotation speed of the electric machine (16).

2. Method according to claim 1, in which the piloting parameter (P) is chosen from the outside temperature, the altitude of the aircraft (2) and a parameter representative of a type of failure of the electrical machine (16).

3. Method according to one of claims 1 and 2, in which the first comparison step (48) comprises a prior step of determining a chart of time evolution profiles of the rotation speed of the electrical machine (16) as a function of the rotation speed of the rotating shaft (6) and the control state of the coupling device (18).

4. Method according to any one of claims 1 to 3, in which the second comparison step (50) comprises the calculation of the gradient of the operating deviation and a step of calculating the gradient of the time evolution profile prior to the second comparison step (50), the value of the detection threshold being determined from the control parameter (P), the gradient of the operating deviation, and the gradient of the rotation speed of the determined electrical machine (16).

5. Method according to any one of claims 1 to 4, comprising a step of delaying (54) the result of the second comparison step (50).

6. Method according to any one of claims 1 to 5, comprising, prior to the step of determining (44) the rotation speed of the electric machine (16), a control of the electric machine (16) in engine mode when the turbomachine (4) is stopped.

7. Method according to claim 6, comprising a rotational blocking of the rotary shaft (6) when the electric machine (16) operates in motor mode.

8. Control module (28) for the operation of a coupling device (18) for a turbomachine (4) of an aircraft (2), the turbomachine (4) comprising a rotating shaft (6) and an electric machine (16), the coupling device (18) being configured to connecting a rotor shaft of the electrical machine (16) to the rotating shaft (6) and having two operating states, a coupled state so as to secure the rotor shaft and the rotating shaft (6) and a decoupled state so as to separate the rotor shaft and the rotating shaft (6), the module (28) comprising: first determination means (30) configured to determine a control state of the coupling device (18) delivered in the form of a control instruction in the coupled state or in the decoupled state of the coupling device (18); second determination means (32) configured to determine the rotational speed of the electrical machine (16), third determination means (34) configured to determine the rotational speed of the rotating shaft (6);first comparison means (36) configured to compare the rotational speed of the electrical machine (16) with a time evolution profile of the rotational speed of the electrical machine (16) determined from the rotational speed of the rotary shaft (6) and the control state of the coupling device (18), the first comparison means (36) being configured to determine an operating deviation; second comparison means (38) configured to compare the operating deviation with a detection threshold; and means for determining a failure (40) configured to identify the existence of a failure or an absence of failure of the coupling device (18) according to the result delivered by the second comparison means (36); characterized in that the second comparison means (36) are further configured to determine the value of the detection threshold at; from at least one control parameter (P), the operating deviation and the rotation speed of the electric machine (16).

9. Turbomachine (4) for aircraft (2) comprising a rotating shaft (6), an electric machine (16), and a coupling device (18) configured to connect a rotor shaft of the electric machine (16) to the rotating shaft (6) and having two operating states, a coupled state so as to secure the rotor shaft and the rotating shaft (6) and a decoupled state so as to separate the rotor shaft and the rotating shaft (6), characterized in that it comprises a control module (28) according to claim 8.

10. Aircraft (2) characterized in that it comprises a turbomachine (4) according to claim 9.

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