Method for controlling a hybrid turbomachine

Abstract

Method for controlling a hybrid turbomachine. Method for controlling a hybrid turbomachine comprising: a first control (110) for determining an electrical torque setpoint, including determining a fuel flow setpoint (ΔWF) as a function of a fuel flow command (WFcons) and a maximum fuel flow (WFmax) and determining (113) a first correction variable (TRQ_correc), and a second control (120) for determining a preliminary setpoint (TRQ) comprising: detecting (122) an intention to accelerate engine speed as a function of a difference between a current engine speed and a turbomachine engine speed command, and determining (121) the preliminary setpoint (TRQ) as a function of real-time data (124),characterized in that the first regulation includes the determination (130) of the electrical torque setpoint as a function of the preliminary setpoint (TRQ) and the first correction quantity (TRQ_correc). Figure for the abbreviation: Fig. 1,

Description

Title of the invention: Method for controlling a hybrid turbomachine. Technical field

[0001] 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. Previous technique

[0002] 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 various states. 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.

[0003] 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 aeronautical components and products that are less energy-intensive, more environmentally friendly, and whose integration and use in civil aviation have moderate environmental consequences, with the aim of improving the energy efficiency of aircraft.

[0004] Consequently, the Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0005] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, in particular through the materials used and lighter on-board equipment, the development of the use of electrical technologies to provide propulsion, and, as essential complements to technological progress, aviation biofuels.

[0006] The electric or hybrid electric / thermal propulsion of conventional aircraft (CTOL), short takeoff and landing (STOL) aircraft and vertical takeoff and landing (VTOL) aircraft is achieved by one or Several electric assist motors. The conventional architecture of electric propulsion systems consists of a DC voltage source connected by power harnesses to a power electronics and control unit, which is itself connected by power harnesses to the electric assist motor, generally powered by AC, and which is in turn connected to a means of transmitting electrical power to the hybrid turbomachine. This allows for supplemental electrical power to be provided to the turbomachine during the various operating phases of the aircraft (start-up or acceleration, for example).

[0007] 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 supplement the power supply to the high-pressure body shaft and continue to follow the trajectory of the target speed (particularly during acceleration), when the high-pressure body compressor reaches its operating limits.

[0008] 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's operability limits are reached, in order to follow the turbomachine's acceleration trajectory. This optimizes battery cycles and electrical consumption.

[0009] 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.

[0010] It is therefore desirable to have a new method for controlling the hybridization of a turbomachine, allowing it to be assisted in real time and only when reaching the stop during acceleration, in a more optimal way than existing open-loop control strategies for the torque setpoint. Description of the invention

[0011] 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: - 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 - the implementation of a second electrical torque regulation loop in order to determine a preliminary electrical torque setpoint including: • detection of an intention to accelerate the turbomachine's speed based on a difference between a current operating speed and a turbomachine speed command, and • a determination of the preliminary electrical torque setpoint based on real-time data from the turbomachine,

[0012] 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.

[0013] 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 the fact 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 point of view 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.

[0014] According to a particular feature of the invention, the implementation of the second electrical torque regulation loop includes a zeroing of the setpoint preliminary electrical torque implemented in case of detection of an intention to accelerate the speed of the turbomachine.

[0015] According to another particular feature of the invention, the implementation of the first electric torque regulation loop includes a detection of a fuel setpoint stop defining the maximum fuel flow.

[0016] According to another particular feature of the invention, the implementation of the first electrical torque regulation loop includes an integration of the preliminary electrical torque setpoint in order to determine the electrical torque setpoint.

[0017] 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.

[0018] 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 control speed of the turbomachine, 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.

[0019] 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.

[0020] According to another particular feature of the invention, the control method comprises 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 regulation loop electrical torque is also a function of the maximum electrical torque setpoint.

[0021] 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.

[0022] Another object of the invention is a computer-readable medium comprising instructions for the execution of the steps of the control process according to the invention, when said instructions are executed by a computer.

[0023] Another object of the invention is an electronic control unit for a turbomachine comprising a memory including instructions for a computer program according to the invention.

[0024] Another object of the invention is a turbomachine comprising an electronic control unit according to the invention.

[0025] Yet another object of the invention is an aircraft comprising a turbomachine according to the invention, the turbomachine being configured to propel said aircraft.

[0026] 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). Brief description of the drawings

[0027] 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.

[0028] [Fig.1] Fig.1 represents, schematically and partially, the two control loops of the control method of a turbomachine according to an embodiment of the invention.

[0029] [Fig.2] Fig.2 represents, schematically and partially, a device of generation of a control of a turbomachine according to another embodiment of the control method of the invention. Description of the implementation methods

[0030] Fig. 1 represents schematically and partially the two loops 110, 120 of regulation of the process 100 of control of a turbomachine according to a first embodiment of the invention.

[0031] In a known manner, the turbomachine is configured to propel an aircraft and comprises a high-pressure body, a low-pressure body, and an electric motor. The high-pressure body comprises 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 body comprises a low-pressure compressor and a The turbomachine consists of two low-pressure turbines connected by a low-pressure shaft. It also includes a fan driven by the same low-pressure shaft. The electric motor is configured to provide electrical power (or inject electrical torque) to the high-pressure shaft to assist the fan. The turbomachine's operation can be controlled by an electronic control unit (ECU) that provides control commands, such as a fuel flow rate or electrical torque command, to the electric motor based on the turbomachine's operating parameters.

[0032] The method 100 includes the implementation of a first control loop 110 and the implementation of a second control loop 120.

[0033] The implementation of the second control loop 120 makes it possible to determine a preliminary electrical torque setpoint TRQ in open loop. It includes a detection 122 of an intention to accelerate the turbomachine's speed based on a difference between a current operating speed and a turbomachine speed command, as well as a 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 the operation of the turbomachine and provided to the electronic control unit. More specifically, the preliminary electrical torque setpoint TRQ can be derived from a calculation of the operability sector.The C / P pumping margin of the high-pressure compressor of the worst-case engine is converted into the required acceleration rate of the high-pressure body, and then the electrical power to be implemented to ensure this acceleration rate is determined.

[0034] The implementation of the second control loop 120 may also include a zeroing 123 of the preliminary electrical torque setpoint TRQ.

[0035] The implementation of the first control loop 110 determines the final electrical torque setpoint TRQ_final. It includes determining a fuel flow setpoint A WF 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. Indeed, to change the turbomachine's operating speed, the pilot of the aircraft containing 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 A WF.The determination 113 of the first correction variable TRQ_correc is, for example, performed by a proportional-integral type controller, in order to control the fuel flow rate WFcons to the maximum fuel flow rate WFmax according to a desired template. This first variable. TRQ_correc correction allows correcting the open-loop law used to determine the preliminary electrical torque setpoint TRQ.

[0036] Finally, the electrical torque setpoint TRQ_final is determined from the first correction quantity TRQ_correc determined by the first control loop 110, and the preliminary electrical torque setpoint TRQ, determined by the second control loop 120.

[0037] The first control loop 110 may include a detection of a fuel setpoint stop 111 defining the maximum fuel flow rate WFmax.

[0038] The second control loop 120 may include an integration of the preliminary setpoint TRQ of electric torque during the determination 130 of the final electric torque setpoint TRQ_final.

[0039] 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 acceleration of the turbomachine. 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.

[0040] This electric assistance, provided by the electric motor and operating according to the open-loop law, prevents disruption to the turbomachine's fuel cycle, since the amount of electric torque supplied by the electric motor is determined relative to the AWF fuel flow setpoint. This also optimizes energy use within the turbomachine during acceleration by precisely determining the required electric assistance.

[0041] Fig. 2 represents, schematically and partially, a device 200 for generating a control of a turbomachine allowing the control method to be implemented according to another embodiment of the invention.

[0042] According to the invention, the device 200 comprises a first regulation loop 210 and a second regulation loop 220.

[0043] As indicated with reference to [Fig. 1], the implementation of the second control loop 220 makes it possible to determine a preliminary electrical torque setpoint TRQ. It includes a detection 222 of an intention to accelerate the turbomachine's speed based on a difference between a current speed (for example, a current high-pressure shaft speed) and a speed command (for example, a high-pressure shaft speed command) of the turbomachine, as well as a determination 221 of the preliminary electrical torque setpoint TRQ based on 224 real-time data from the turbomachine. This 224 data can come from various measurements taken by sensors during the operation of the turbomachine and supplied to the electronic control unit.

[0044] The implementation of the second control loop 220 may also include a zeroing 223 of the preliminary electrical torque setpoint TRQ.

[0045] The implementation of the first control loop 210 allows for the determination of an electrical torque setpoint TRQ_final based on the fuel flow rate. It includes determining a fuel flow rate setpoint A_WF 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 value TRQ_correc is determined 213 from the fuel flow rate setpoint A_WF. Finally, the electrical torque setpoint TRQ_final is determined 230 from the preliminary setpoint TRQ, determined by the second control loop 220, and the first correction value TRQ_correc.

[0046] The first control loop 210 may include a detection of a fuel setpoint stop 211 defining the maximum fuel flow rate WFmax.

[0047] The second control loop 220 may include an integration of the preliminary setpoint TRQ of electrical torque in order to determine the final electrical torque setpoint TRQ according to the fuel flow rate.

[0048] The device 200, and therefore the control method, may also include a third electrical torque control loop 230 to determine an intermediate setpoint TRQ_EGT for electrical torque. To this end, the third control loop 230 determines the difference AEGT between a maximum temperature EGTmax of the exhaust gases at the turbomachine outlet and a measured temperature EGTmes of the exhaust gases at the turbomachine outlet. From this difference AEGT, the third control loop 230 determines 233 an intermediate setpoint TRQ_EGT for electrical torque. This determination 233 is, for example, performed by a proportional-integral controller which calculates the electrical assistance required to limit the exhaust gas temperature EGT at the turbomachine outlet to its maximum limit according to a desired specification.

[0049] The device 200, and therefore the control method, may also include a fourth electrical torque control loop 250 in order to determine a second electrical torque correction parameter. This fourth control loop 250 makes it possible to regulate the electrical torque drawn from the electric motor when a low fuel flow limit WFmin is reached, particularly in the event of turbomachine deceleration. For this purpose, the fourth control loop 250 includes a detection 252 of an intention to decelerate turbomachine operating regime as a function of a difference between a current operating regime and a turbomachine operating regime command, as well as a determination 251 of a second electrical torque correction quantity as a function of real-time data 254 of the turbomachine.

[0050] The fourth control loop 250 may also include a zeroing 253 of the second electrical torque correction quantity.

[0051] The device 200, and therefore the control method, may also include a fifth electrical torque control loop 240 in order to determine a third electrical torque correction parameter. This fifth control loop 240 makes it possible to take into account a turbomachine start-up law 241 in order to determine the third electrical torque correction parameter from measurements 244 carried out within the turbomachine and the start-up law 241.

[0052] 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 chamber drives the engine shafts). In a starting sequence, the choke or starter (electric machine) mechanically drives the engine's high-pressure shaft.

[0053] The measures 244 include the high-pressure body regime and / or the high-pressure compressor inlet temperature.

[0054] The device 200, and therefore the control method, may also include a sixth electrical torque control loop 260 for determining 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.

[0055] The device 200, and therefore the control method, may also include a seventh electrical torque control loop 270 that takes 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 not faulty and takes this fault into account when determining the torque setpoint. It avoids overloading the integrators of the various control loops.

[0056] The electrical torque setpoint TRQcons is then determined as a function of all the correction parameters and all the preliminary and intermediate setpoints determined by the different control loops 210, 220, 230, 240, 250, 260 and 270 present in device 200. But it is also possible to deactivate one of the regulation 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 part of the other correction quantities and / or the intermediate setpoint TRQ_EGT.

[0057] The control loops 210, 220, 230, 240, 250, 260, 270 of device 200 are implemented by one or more control modules.

[0058] The method described with reference to Figures 1 and 2 can be implemented in the form of instructions executed by a computer program when the latter is run by a computer. This computer program can also be implemented in a memory contained within an electronic control unit of a turbomachine.

Claims

1. Demands 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 (TRQ_final), said first loop comprising a determination of a fuel flow setpoint (AWF) as a function of a fuel flow control (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), and - the implementation of a second (120, 220) electrical torque regulation loop in order to determine a preliminary electrical torque setpoint (TRQ) comprising: • a 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 • a determination (121, 221) of the preliminary setpoint (TRQ) of electrical torque as a function of real-time data (124, 224) from the turbomachine, the process being characterized in that the implementation of the first control loop includes the determination (130, 230) of the electrical torque setpoint (TRQ_final) as a function of the preliminary electrical torque setpoint (TRQ) and the first electrical torque correction value (TRQ_correc).

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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