Method for controlling a hybrid turbine engine

Abstract

The invention relates to a method for controlling a hybrid turbine engine, comprising: - a first control (110) to determine an electric torque setpoint, comprising determining a fuel flow rate setpoint (ΔWF) on the basis of a fuel flow rate command (WFcons) and a maximum fuel flow rate (WFmax), and determining (113) a first correction quantity (TRQ_correc), and - a second control (120) to determine a preliminary setpoint (TRQ), comprising: o detecting (122) an intention to accelerate the speed, on the basis of the difference between a current speed and a turbine engine speed command, and o determining (121) the preliminary setpoint (TRQ) on the basis of real-time data (124), characterized in that the first control comprises determining (130) the electric torque setpoint on the basis of the preliminary setpoint (TRQ) and the first correction quantity (TRQ_correc).

Description

[0001] Description

[0002] Title of the invention: Method for controlling a hybrid turbomachine

[0003] Technical Field

[0004] The present invention relates to the general field of turbomachinery, and more particularly to the control of a turbomachine comprising an electric motor during its acceleration.

[0005] Previous technique

[0006] Climate change is a major concern for many legislative and regulatory bodies worldwide. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by different countries. In particular, an ambitious standard applies to both new types of aircraft and those already in service, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively working for several years now to contribute to the fight against climate change.

[0007] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into account the factors impacting all phases of design and development in order to obtain less energy-intensive and more environmentally friendly aeronautical components and products, whose integration and use in civil aviation have moderate environmental consequences, with the aim of improving the energy efficiency of aircraft.

[0008] Consequently, the Applicant is constantly working to reduce its negative climate impact by employing environmentally sound methods and processes for development and manufacturing that minimize greenhouse gas emissions to the absolute minimum possible in order to reduce the environmental footprint of its activities. This sustained research and development work focuses on new generations of aircraft engines, aircraft weight reduction, particularly through the use of lighter materials and onboard equipment, the development of electric propulsion technologies, and, as essential complements to technological progress, aviation biofuels.

[0009] Electric or hybrid electric / thermal propulsion for conventional aircraft (CTOL), short takeoff and landing (STOL), and vertical takeoff and landing (VTOL) aircraft is achieved using one or more electric assist motors. The conventional architecture of electric propulsion systems consists of a direct current (DC) power source connected via power harnesses to a power electronics and control unit, which is itself connected via power harnesses to the electric assist motor, typically powered by alternating current (AC). This motor is then connected to a means of transmitting electrical power to the hybrid turbomachine. This provides supplemental electrical power to the turbomachine during the various operating phases of the aircraft (such as start-up or acceleration).

[0010] Traditionally, the electric torque supplied by the electric motor to the turbomachine is modulated only when the turbomachine is constrained by its operability limits (maximum and minimum fuel flow rates, also called stops, to protect the high-pressure compressor of the turbomachine from pumping during acceleration or to protect the combustion chamber and the low-pressure compressor of the turbomachine from extinction during deceleration).The architecture for regulating the hybridization rate of the turbomachine, i.e. the proportion of electrical power supplied by the electric motor compared to the proportion of mechanical power supplied by the high-pressure body, is based on single-variable controllers that work in parallel by mixing fuel and electrical torque in order to be able to supplement the power supply on the shaft of the high-pressure body and continue to follow the trajectory of the target speed (especially in acceleration), when the compressor of the high-pressure body reaches its limits of operability.

[0011] This control architecture has the advantage of minimizing the use of the electric assist motor based on an operability limit criterion. Thus, hybrid solutions exist to assist the turbomachine's acceleration by injecting electric torque only when the high-pressure compressor reaches its operability limits, in order to follow the turbomachine's acceleration trajectory. This optimizes battery cycles and energy consumption.

[0012] However, when the electrical torque setpoint is made in a closed loop, it is established with a delay compared to the optimum of an open-loop law; and an open-loop electrical assistance would have the disadvantage of assisting the turbomachine all the time, whether or not it is at the limit (i.e., at the limit of operability) to follow the acceleration trajectory.

[0013] It is therefore desirable to have a new method of controlling the hybridization of a turbomachine, allowing it to be assisted in real time and only when reaching the end stop during acceleration, in a more optimal way than existing open-loop control strategies of the torque setpoint.

[0014] Description of the invention

[0015] To this end, the invention relates to a method for controlling a turbomachine configured to propel an aircraft and comprising a high-pressure body, a low-pressure body, and an electric motor, the high-pressure body comprising at least one shaft and the electric motor being configured to inject an electrical torque onto the shaft of the high-pressure body, the control method being implemented by a computer and comprising:

[0016] - the implementation of a first electrical torque regulation loop to determine an electrical torque setpoint, said first loop comprising a determination of a fuel flow setpoint as a function of a fuel flow control dependent on a control lever position and a maximum fuel flow, and comprising a determination of a first correction value, and

[0017] - the implementation of a second electrical torque control loop in order to determine a preliminary electrical torque setpoint comprising: o a detection of an intention to accelerate the turbomachine speed as a function of a difference between a current speed and a turbomachine speed command, and o a determination of the preliminary electrical torque setpoint as a function of real-time data from the turbomachine, the method being characterized in that the implementation of the first control loop includes the determination of the electrical torque setpoint as a function of the preliminary electrical torque setpoint and the first electrical torque correction quantity.

[0018] Thanks to the control method according to the invention, the electrical torque setpoint is determined based on the first correction variable, which takes into account the fuel flow setpoint, and the preliminary electrical torque setpoint, which takes into account that the turbomachine is in acceleration mode. A first advantage is that the turbomachine can be assisted during acceleration by injecting torque from an electric motor, while optimizing the amount of torque injected from the perspective of electrical consumption and battery cycles. A second advantage is that the assistance provided by the electric motor's torque injection does not disrupt the fuel loop.

[0019] According to a particular feature of the invention, the implementation of the second electrical torque regulation loop includes a zeroing of the preliminary electrical torque setpoint implemented in the event of detection of an intention to accelerate the speed of the turbomachine.

[0020] According to another particular feature of the invention, the implementation of the first electric torque control loop includes detecting a fuel setpoint limit that defines the maximum fuel flow rate. According to another particular feature of the invention, the implementation of the first electric torque control loop includes integrating the preliminary electric torque setpoint to determine the final electric torque setpoint.

[0021] According to another particular feature of the invention, the control method includes the implementation of a third electrical torque control loop in order to determine an intermediate electrical torque setpoint as a function of a difference between a measurement of a turbomachine exhaust gas temperature and a maximum turbomachine exhaust gas temperature, the determination of the electrical torque setpoint implemented by the first electrical torque control loop also being a function of the intermediate electrical torque setpoint.

[0022] According to another particular feature of the invention, the control method includes the implementation of a fourth electrical torque regulation loop in order to determine a second electrical torque correction quantity comprising a detection of an intention to decelerate the speed of the turbomachine as a function of a difference between a current speed and a turbomachine speed command, and a determination of a second electrical torque correction quantity as a function of real-time data from the turbomachine, the determination of the electrical torque setpoint implemented by the first electrical torque regulation loop also being a function of the second electrical torque correction quantity.

[0023] According to another particular feature of the invention, the control method includes the implementation of a fifth electrical torque regulation loop in order to determine a third electrical torque correction quantity, the determination of the electrical torque setpoint implemented by the first electrical torque regulation loop also being a function of the third electrical torque correction quantity.

[0024] According to another particular feature of the invention, the control method includes the implementation of a sixth electrical torque regulation loop in order to determine a maximum electrical torque setpoint, the determination of the electrical torque setpoint implemented by the first electrical torque regulation loop also being a function of the maximum electrical torque setpoint.

[0025] Another object of the invention is a computer program comprising instructions for executing the steps of the control method according to the invention when said program is executed by a computer.

[0026] Another object of the invention is a computer-readable medium comprising instructions for executing the steps of the control process according to the invention, when said instructions are executed by a computer.

[0027] Another object of the invention is an electronic control unit for a turbomachine comprising a memory containing instructions for a computer program according to the invention.

[0028] Another object of the invention is a turbomachine comprising an electronic control unit according to the invention.

[0029] Yet another object of the invention is an aircraft comprising a turbomachine according to the invention, the turbomachine being configured to propel said aircraft.

[0030] According to a particular feature of the invention, the aircraft is a vertical takeoff and landing (VTOL) aircraft or a short takeoff and landing (STOL) aircraft or a conventional aircraft (CTOL).

[0031] Brief description of the drawings

[0032] Other features and advantages of the present invention will become apparent from the description given below, with reference to the attached drawings which illustrate examples of embodiment without any limiting character.

[0033] [Fig. 1] Figure 1 schematically and partially illustrates the two control loops of the turbomachine control method according to one embodiment of the invention. [Fig. 2] Figure 2 schematically and partially illustrates a device for generating a control signal for a turbomachine according to another embodiment of the control method of the invention.

[0034] Description of the implementation methods

[0035] Figure 1 schematically and partially represents the two loops 110, 120 of regulation of the process 100 of control of a turbomachine according to a first embodiment of the invention.

[0036] As is known, a turbomachine is configured to propel an aircraft and comprises a high-pressure section, a low-pressure section, and an electric motor. The high-pressure section includes a high-pressure compressor and a high-pressure turbine connected by a high-pressure shaft, as well as a combustion chamber; while the low-pressure section includes a low-pressure compressor and a low-pressure turbine connected by a low-pressure shaft. The turbomachine also includes a fan driven by the low-pressure shaft. The electric motor is configured to provide electrical power (or inject electrical torque) to the high-pressure shaft to assist it.The operation of the turbomachine can be controlled by an electronic control unit which provides control instructions, for example a fuel flow setpoint or an electrical torque setpoint to the electric motor, from operating parameters of the turbomachine.

[0037] Process 100 includes the implementation of a first control loop 110 and the implementation of a second control loop 120.

[0038] The implementation of the second control loop 120 allows for the determination of a preliminary open-loop electrical torque setpoint TRQ. It includes the detection 122 of an intention to accelerate the turbomachine's speed based on the difference between a current operating speed and a turbomachine speed command, as well as the determination 121 of the preliminary electrical torque setpoint TRQ based on real-time data 124 from the turbomachine. This data 124 can be derived from various measurements taken by sensors during turbomachine operation and provided to the electronic control unit. More specifically, the preliminary electrical torque setpoint TRQ can be derived from an operability sector calculation.The C / P pumping margin of the worst-case high-pressure compressor of the engine is converted into the required high-pressure body acceleration rate, and then the electrical power to be implemented to ensure this acceleration rate is determined.

[0039] The implementation of the second control loop 120 may also include a zeroing 123 of the preliminary electrical torque setpoint TRQ.

[0040] The implementation of the first control loop 110 determines the final electrical torque setpoint TRQ_final. This includes determining a fuel flow setpoint AWF based on the difference between a fuel flow command 112 WFcons and a maximum fuel flow WFmax. The fuel flow command WFcons is determined by the position of a control lever 112. To change the turbomachine's operating speed, the pilot of the aircraft equipped with this turbomachine changes the position of the control lever 112, which modifies the fuel flow command WFcons. Then, a first correction value TRQ_correc 113 is determined from the fuel flow setpoint AWF.The determination of the first correction variable TRQ_correc is, for example, performed by a proportional-integral controller, in order to control the fuel flow rate WFcons to the maximum fuel flow rate WFmax according to a desired template. This first correction variable TRQ_correc corrects the open-loop law used to determine the preliminary electrical torque setpoint TRQ.

[0041] Finally, we determine 130 the electrical torque setpoint TRQJïnal from the first correction quantity TRQ_correc determined by the first regulation loop 110, and the preliminary electrical torque setpoint TRQ, determined by the second regulation loop 120.

[0042] The first control loop 110 may include the detection of a fuel setpoint limit 111 defining the maximum fuel flow rate WFmax. The second control loop 120 may include the integration of the preliminary electrical torque setpoint TRQ during the determination 130 of the final electrical torque setpoint TRQ_final.

[0043] Thus, thanks to the two control loops 110 and 120, an electrical torque from the electric motor is injected in open loop with a closed-loop correction, using the first electrical torque correction variable TRQ_correc. This first correction variable TRQ_correc allows the preliminary electrical torque setpoint TRQ to be increased if the contribution determined by the open-loop law (resulting from determination 121) is insufficient to assist the turbomachine's acceleration. It can also, particularly in the case of a new turbomachine with an acceleration margin, reduce the electrical torque if the open-loop law is not required.

[0044] This electric assistance, provided by the electric motor and operating according to open-loop principles, prevents disruption to the turbomachine's fuel cycle, as the amount of electric torque supplied by the electric motor is determined by the AWF fuel flow setpoint. This also optimizes energy use within the turbomachine during acceleration by precisely determining the required level of electric assistance.

[0045] Figure 2 schematically and partially represents a device 200 for generating a control of a turbomachine allowing the control method to be implemented according to another embodiment of the invention.

[0046] According to the invention, the device 200 comprises a first regulation loop 210 and a second regulation loop 220.

[0047] As shown with reference to Figure 1, the implementation of the second control loop 220 allows for the determination of a preliminary electrical torque setpoint TRQ. It includes the detection 222 of an intention to accelerate the turbomachine's speed based on a difference between a current operating speed (e.g., a high-pressure shaft operating speed) and a speed command (e.g., a high-pressure shaft speed command) of the turbomachine, as well as the determination 221 of the preliminary electrical torque setpoint TRQ based on real-time data 224 from the turbomachine. This data 224 can be derived from various measurements taken by sensors during turbomachine operation and supplied to the electronic control unit.

[0048] The implementation of the second regulation loop 220 may also include a zeroing 223 of the preliminary electrical torque setpoint TRQ.

[0049] The implementation of the first control loop 210 allows for the determination of an electrical torque setpoint TRQJïnal based on the fuel flow rate. It includes determining a fuel flow rate setpoint AWF from the difference between a fuel flow rate command 212 WFcons and a maximum fuel flow rate WFmax. The fuel flow rate command WFcons is determined by the position of a control lever 212. Then, a first correction variable TRQ_correc is determined 213 from the fuel flow rate setpoint AWF. Finally, the electrical torque setpoint TRQJïnal is determined 230 from the preliminary setpoint TRQ, determined by the second control loop 220, and the first correction variable TRQ_correc.

[0050] The first control loop 210 may include a detection of a fuel setpoint stop 211 defining the maximum fuel flow rate WFmax.

[0051] The second 220 regulation loop may include an integration of the preliminary TRQ electrical torque setpoint in order to determine the TRQJïnal electrical torque setpoint according to the fuel flow rate.

[0052] The device 200, and therefore the control method, may also include a third electrical torque control loop 230 to determine an intermediate electrical torque setpoint TRQ_EGT. To this end, the third control loop 230 determines the difference AEGT between a maximum exhaust gas temperature EGTmax and a measured exhaust gas temperature EGTmes. From this difference AEGT, the third control loop 230 determines 233 an intermediate electrical torque setpoint TRQ_EGT. This determination 233 is, for example, performed by a proportional-integral controller that calculates the electrical assistance required to limit the exhaust gas temperature EGT at the turbomachine outlet to its maximum limit according to a desired parameters.

[0053] The device 200, and therefore the control method, may also include a fourth electrical torque control loop 250 to determine a second electrical torque correction parameter. This fourth control loop 250 allows the electrical torque drawn from the electric motor to be regulated when a low fuel flow limit WFmin is reached, particularly in the event of turbomachine deceleration. To this end, the fourth control loop 250 includes a detection 252 of an intention to decelerate the turbomachine's speed based on a difference between a current operating speed and a turbomachine speed command, as well as a determination 251 of a second electrical torque correction parameter based on real-time data 254 from the turbomachine.

[0054] The fourth regulation loop 250 may also include a zeroing 253 of the second electrical torque correction quantity.

[0055] The device 200, and therefore the control method, may also include a fifth electrical torque control loop 240 to determine a third electrical torque correction parameter. This fifth control loop 240 allows for the consideration of a turbomachine start-up law 241 to determine the third electrical torque correction parameter from measurements 244 taken within the turbomachine and the start-up law 241.

[0056] Starting law 241 is a law representing the action of switching, on the pilot's command, the engine from the off state (a state without internal combustion and without rotation of the engine shafts except for relative wind) to the idling state (a state in which the energy of combustion in the combustion chamber drives the engine shafts). In a starting sequence, the choke or starter (electric machine) mechanically drives the engine's high-pressure shaft. Measurements 244 include the high-pressure body speed and / or the high-pressure compressor inlet temperature.

[0057] The device 200, and therefore the control method, may also include a sixth electrical torque control loop 260 to determine a maximum electrical torque setpoint from data or measurements 264 of the turbomachine. The maximum electrical torque setpoint is determined, in particular, based on a maximum electrical torque limit 261 that can be extracted from the electric motor and a maximum electrical torque limit 262 that can be supplied to the high-pressure shaft of the high-pressure unit. The data or measurements 264 are of several types: speeds, temperatures, and / or pressures.

[0058] The device 200, and therefore the control method, may also include a seventh electrical torque control loop 270 to take into account the state of the turbomachine, in particular the state of the aircraft's electric propulsion system (which includes the electric motor). The seventh control loop 270 verifies that the electrical system is functioning correctly and takes this fault into account when determining the torque setpoint. It avoids overloading the integrators of the various control loops.

[0059] The electrical torque setpoint TRQcons is then determined based on all correction quantities and all preliminary and intermediate setpoints determined by the different control loops 210, 220, 230, 240, 250, 260 and 270 present in the device 200. But it is also possible to deactivate one of the control loops 230, 240, 250, 260 or 270 to determine the electrical torque setpoint TRQcons based only on the first correction quantity TRQ_correc, the preliminary setpoint TRQ and some of the other correction quantities and / or the intermediate setpoint TRQ-EGT.

[0060] The control loops 210, 220, 230, 240, 250, 260, 270 of device 200 are implemented by one or more control modules.

[0061] The process described with reference to Figures 1 and 2 can be implemented as instructions executed by a computer program when that program is run by a computer. This computer program can also be implemented in memory within the electronic control unit of a turbomachine.

Claims

Demands

1. A method for controlling a turbomachine configured to propel an aircraft and comprising a high-pressure body, a low-pressure body, and an electric motor, the high-pressure body comprising at least one shaft and the electric motor being configured to inject an electrical torque onto the shaft of the high-pressure body, the control method being implemented by computer and comprising: - the implementation of a first electrical torque control loop (110, 210) to determine an electrical torque setpoint (TRQJïnal), said first loop comprising a determination of a fuel flow setpoint (AWF) as a function of a fuel flow command (WFcons) dependent on a position of a control lever (112, 212) and a maximum fuel flow (WFmax) and comprising a determination (113, 213) of a first electrical torque correction value (TRQ_correc) from the fuel flow setpoint (AWF), and - the implementation of a second electrical torque control loop (120, 220) to determine a preliminary electrical torque setpoint (TRQ) comprising: o detection (122, 222) of an intention to accelerate the turbomachine's speed based on a difference between a current operating speed and a turbomachine speed command, and o determination (121, 221) of the preliminary electrical torque setpoint (TRQ) based on real-time turbomachine data (124, 224) when an intention to accelerate the turbomachine's speed is detected, the method being characterized in that the implementation of the first control loop comprises the determination (130, 230) of the electrical torque setpoint (TRQ) based on the preliminary torque setpoint (TRQ) electrical and the first correction quantity (TRQ_correc) of electrical torque.

2. A control method according to claim 1, wherein the implementation of the second electrical torque control loop includes a zeroing (123, 223) of the preliminary electrical torque setpoint (TRQ) implemented in the event of detection of an intention to accelerate the speed of the turbomachine.

3. A control method according to any one of claims 1 or 2, wherein the implementation of the first electrical torque control loop includes a detection (111, 211) of a fuel setpoint stop defining the maximum fuel flow.

4. A control method according to any one of claims 1 to 3, wherein the implementation of the second electrical torque regulation loop includes an integration of the preliminary electrical torque setpoint (TRQ) in order to determine the electrical torque setpoint.

5. Computer program comprising instructions for carrying out the steps of the control process according to any one of claims 1 to 4 when said program is executed by a computer.

6. Computer-readable medium comprising instructions for carrying out the steps of the control process according to any one of claims 1 to 4, when said instructions are executed by a computer.

7. Electronic control unit of a turbomachine comprising a memory comprising instructions of a computer program according to claim 5.

8. Turbomachine comprising an electronic control unit according to claim 7.

9. Aircraft comprising a turbomachine according to claim 8, the turbomachine being configured to propel said aircraft.

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