Method for controlling the hybridisation rate of a hybrid turbine engine

Abstract

The invention relates to a method (100) for controlling the hybridisation rate of a hybrid turbine engine, the control method (100) comprising at least: - a step of determining electric torque control saturation (102), in particular on the basis of a first static saturation law and a first dynamic saturation law, the dynamic saturation law being in particular defined on the basis of a target hybridisation rate; - a step of determining fuel-flow control saturation (103); - a step of determining electric torque control and fuel-flow control (105) using a corrector that takes into account at least - a difference between the engine speed to be reached and the current engine speed, - an electric torque control saturation, and - a fuel-flow control saturation, so as to obtain the target hybridisation rate.

Description

DESCRIPTION TITLE: Method for controlling the hybridization rate of a hybridized turbomachine FIELD OF THE INVENTION

[0001] The invention belongs to the field of turbomachines for aeronautics, and in particular to the field of hybridized turbomachines. The invention relates to a method for controlling the hybridization rate of a hybridized turbomachine. The invention also relates to a hybridized turbomachine implementing such a method for controlling the hybridization rate. Finally, the invention further relates to an aircraft comprising a hybridized turbomachine according to the invention. STATE OF THE ART

[0002] The hybridization of turbomachines today meets various needs, such as limiting the temperature of exhaust gases, distributing power draws between the different bodies of the turbomachine, adjusting the engine operating line during an engine transient or even optimizing stability.

[0003] The control of a hybrid turbomachine is achieved using multi-variable closed loops taking, as input, a speed trajectory setpoint. Such closed loops provide, as output, a fuel flow control and an electric torque control for each electric machine present in the turbomachine.

[0004] A hybrid twin-spool / double-flow turbomachine comprises a low-pressure electric machine connected to the low-pressure shaft, and a high-pressure electric machine connected to the high-pressure shaft. In such a case, the multi-variable closed loop will have three output controls: - a fuel flow control, - a low-pressure electric machine torque control and - a high-pressure electric torque control.

[0005] In automation, a system with a different number of inputs and output controls is called a rectangular system, in particular a MISO type system, acronym for "Multi Input Single Output" in English, a system SIMO type, acronym for "Single Input Multiple Output" in English, or a MIMO type system, acronym for "Multiple Input Multiple Output" in English. In other words, a single instruction must regulate at least two commands.

[0006] This arrangement poses problems because the system has a single error rejection dynamic. The distribution of orders is therefore fixed, without the possibility of changing it dynamically.

[0007] On the other hand, in a classical automation problem, we seek to obtain a square system to have as many commands as setpoints. Such an arrangement makes it possible to influence both commands by varying the two setpoints.

[0008] In the case of a hybrid turbomachine, a system equation allows the calculation of an energy distribution between the fuel flow and an electric torque. When an increase in speed is made, it can be done only with fuel flow or electric torque, and intrinsically with the dimensioning of the machine. In this case, the fuel flow and the electric torque will always take the same proportion in a corrector without the possibility of modifying a thermal / electric hybridization rate, during use of a regulator.

[0009] In other words, in a hybrid turbomachine, according to the state of the art, the distribution of thermal / electrical energy is constant over time and is fixed by the operating point of the engine and the sizing of the different parts of the machine. If we operate around a given speed, the distribution of fuel flow and electric torque is always the same.

[0010] However, such a method of controlling a hybrid turbomachine is not satisfactory, because it does not allow the fuel flow / electric torque hybridization rate to be modified.

[0011] In particular, it is not possible to adapt the hybridization rate as a function of other operating parameters of the hybridized turbomachine. For example, it is not possible to modulate the hybridization rate dynamically to respond to a variation in battery charge level or to total or partial unavailability of an electrical source, in particular due to failure. SUMMARY OF THE INVENTION

[0012] The invention provides a solution to at least some of the problems mentioned above by means of a method for controlling the fuel flow / electric torque hybridization rate in a hybridized turbomachine. This is achieved by dynamically modifying the saturation of the controls, so as to obtain a constraint on one of the energy sources and compensation on one of the other energy sources.

[0013] To this end, a first aspect of the invention is a method for controlling the hybridization rate of a hybridized turbomachine, the control method comprising at least: o a step of determining the saturation of an electric torque control, in particular from a static saturation law and a first dynamic saturation law, the dynamic saturation law being defined from a targeted hybridization rate; o a step of determining the saturation of a fuel flow control; o a step of determining an electric torque control and a fuel flow control using a corrector taking into account at least: o a difference between the engine speed to be achieved and the engine speed in place, o a saturation of the electric torque control and o a saturation of the fuel flow control, so as to obtain the targeted hybridization rate.

[0014] The term "hybridization rate" refers to a fuel flow / electric torque ratio applied to the turbomachine.

[0015] The term "static saturation law" means a criterion expressing a saturation of protection of the fuel flow and electric torque controls.

[0016] The term "dynamic saturation law" refers to a criterion linked to the target hybridization rate.

[0017] More precisely, a static saturation is fixed in the sense that it is taken into account a priori in a definition of the regulator.

[0018] Conversely, dynamic saturation depends on parameters external to the regulator and cannot be taken into account in a regulator definition.

[0019] In the context of the invention, it is proposed to act dynamically, that is to say during use of the regulated turbomachine, on saturations which depend on thermodynamic parameters, which are not strictly speaking static.

[0020] The term "corrector" or "regulator" means a control loop producing at output parameters to be obtained in order to pursue at least one setpoint, such as a fuel flow control and an electric torque control to be applied to the hybrid turbomachine.

[0021] The term “engine speed in place” means an engine speed at the time of application of the control method according to the invention.

[0022] The control method according to the invention dynamically modifies the saturations to modify the thermal / electric hybridization rate. In other words, the saturations are no longer considered solely as physical protections for the turbomachine engine and the electrical machines. On the contrary, the saturations are over-constrained to reduce the use of one energy compared to the other. The reduction will be compensated by the corrector or regulator by increasing the energy source that is not over-constrained.

[0023] Over-constraint is achieved by defining a dynamic saturation law that allows the share of the electrical torque in the hybridization rate to be modified. The dynamic saturation law is therefore a way of constraining saturations.

[0024] For example, the dynamic saturation law can be constructed using a fuzzy corrector, taking into account in particular a certain number of motor parameters, in particular taking into account at least one electrical parameter and / or at least one motor parameter, to construct saturation constraints to be applied to the output commands of the regulator.

[0025] In the context of the invention, saturation therefore plays a different role from the saturations of the state of the art, which are fixed and only play a protective role.

[0026] In other words, the dynamic saturation of the control method according to the invention is a non-linearity which takes the regulator out of the conventional operating mode. This is an additional constraint because it is necessary to ensure the stability of the correction network when it enters these saturations.

[0027] In a state-of-the-art control problem, we always seek to have as many instructions as commands without seeking to over-constrain saturation other than to physically protect the machine.

[0028] In the context of the invention, the lack of instructions is remedied by using the saturation bias to construct a distribution between the commands.

[0029] In addition to the machine protection saturation, which represents a static saturation, the control method according to the invention constructs a dynamic saturation which makes it possible to distribute the energies on the motor according to needs other than the protection needs. Such a dynamic saturation is placed between the limits of the static machine protection saturation.

[0030] In addition to the characteristics which have just been mentioned in the preceding paragraphs, the control method according to one aspect of the invention may have one or more additional characteristics among the following, considered individually or according to all technically possible combinations: - the dynamic saturation law includes an over-constraint of the protection saturation of the electric torque control; - the dynamic saturation law of the electric torque control is constructed from a fuzzy controller, notably taking into account at least one electrical parameter and one motor parameter; - the electrical parameter is the charge level of a battery connected to an electric machine of the hybrid turbomachine and / or the engine parameter is the temperature of the exhaust gases; - the fuzzy controller uses linguistic parameters described by Gaussian laws and a defuzzification method of the “Average of maxima” type; - the fuzzy controller uses linguistic parameters described by non-Gaussian laws and a “centroid” type method; - the control method further comprises: o a reception step, during which an engine speed setpoint to be reached is received; o a step of determining the difference, during which a difference between the engine speed to be reached and the engine speed in place is determined; - the determination of the saturation of the electric torque control is carried out by choosing the smallest saturation among the static saturation and the dynamic saturation; and / or - the dynamic saturation law is expressed by interpolation.

[0031] Another aspect of the invention relates to a hybridized turbomachine, in particular a dual-spool / dual-flow hybridized turbomachine, with variable hybridization rate comprising the following elements: o a propulsion system having, as input, a fuel flow control; o an electric machine, connected to the propulsion system and having, as input, an electric torque control; and o calculation means configured to determine the fuel flow control and the electric torque control by implementing the method according to the first aspect of the invention.

[0032] By implementing the hybridization rate control method, the hybridized turbomachine according to the invention can dynamically modify the fuel flow / electric torque ratio.

[0033] The hybridized turbomachine according to one aspect of the invention may have one or more complementary characteristics among the following, considered individually or according to all technically possible combinations: o the hybridized turbomachine is a double-spool / double-flow turbomachine; o the propulsion system comprises a fan, a low-pressure shaft, a high-pressure compressor, a combustion chamber, a high-pressure shaft, a high-pressure turbine and a low-pressure turbine; and / or o the electric machine comprises a low-pressure electric machine connected to the low-pressure shaft and a high-pressure electric machine connected to the high-pressure shaft. BRIEF DESCRIPTION OF THE FIGURES

[0034] The figures are presented for information purposes only and in no way limit the invention.

[0035] [Figure 1] is a schematic representation of a control method according to the invention;

[0036] [Figure 2] shows a “multi-input single-output” type regulation diagram according to one embodiment of the invention;

[0037] [Figure 3] shows the effect of hybridization rate management by control saturation according to one embodiment of the invention;

[0038] [Figure 4] shows an example of fuzzy rules and linguistic parameters for constraining the level of hybridization according to one embodiment of the invention;

[0039] [Figure 5] and [Figure 6] show, respectively, an injection authorization law and a sampling authorization law as a function of an engine parameter and an electrical parameter according to an embodiment of the invention;

[0040] [Figure 7] shows an example of the evolution of the injection and power extraction constraints as a function of the input parameters; and

[0041] [Figure 8] shows a schematic representation of a hybridized turbomachine according to the invention. DETAILED DESCRIPTION

[0042] Unless otherwise specified, the same element appearing in different figures has a single reference.

[0043] Figure 1 schematically illustrates a method 100 for controlling the hybridization rate of a hybridized turbomachine according to the invention.

[0044] The control method 100 comprises a reception step 101, during which an engine speed setpoint to be reached is received.

[0045] The control method 100 further comprises a step of determining the saturation of the electric torque control 102, during which a saturation of an electric torque control is determined, in particular from a first static saturation law SS and a first dynamic saturation law SD.

[0046] The first static saturation law SS represents a protection saturation of the electrical machine.

[0047] In particular, the first dynamic saturation law SD is defined from a targeted hybridization rate TH. The first dynamic saturation law SD is therefore linked to the targeted hybridization rate TH and can be defined from several parameters of the turbomachine.

[0048] The control method 100 further comprises a step of determining saturation of a fuel flow control 103, during which a saturation of a fuel flow control is determined. According to one embodiment, the saturation of the fuel flow control, in particular from a second static saturation law.

[0049] The second static saturation law represents a thermal engine protection saturation.

[0050] The control method 100 further comprises a step of determining a deviation 104, during which a deviation between the engine speed to be reached, determined during the reception step 101, and an engine speed in place during the implementation of the control method 100 is determined.

[0051] The control method 100 further comprises a step of determining electric torque and fuel flow commands 105, during which an electric torque command and a fuel flow electric torque command to be applied are determined.

[0052] The step of determining electric torque and fuel flow commands 105 is carried out by taking into account both the difference between the engine speed to be reached and the engine speed in place, obtained during the step of determining the difference 104 as well as the saturation of the electric torque command, obtained during the step of determining the saturation of the electric torque command 102, and the saturation of the fuel flow command, obtained during the step of determining the saturation of a fuel flow command 103.

[0053] The ability to modify the dynamic saturation of the electric torque control allows the hybridization rate of the turbomachine to be modified in real time.

[0054] According to the invention, the step of determining the saturation of the electric torque control 102 and the step of determining the saturation of a fuel flow control 103 may be sequential, one after the other, or be at least partially in parallel, one of the steps being carried out at the same time as another step.

[0055] Figure 2 shows a “multi-input single-output” type regulation diagram allowing control modulation via saturation according to an embodiment of the invention. In other words, Figure 2 illustrates an embodiment of the step of determining electric torque control saturation 102 and of the step of determining the electric torque and fuel flow controls 105 of the control method 100 according to the invention.

[0056] Figure 2 illustrates how the dynamic saturation law SD is obtained from a target hybridization rate TH. A torque control saturation electric SE is calculated as the smaller of the dynamic saturation SD and the static saturation SS.

[0057] A CO corrector, or CO regulator, uses the electric torque saturation SE, the saturation of the fuel flow command SC and the difference between the engine speed to be reached RA and the engine speed in place RP to calculate an electric torque command to be applied Cf and a fuel flow command to be applied Df to the hybrid turbomachine TMH.

[0058] The CO regulator also has an input consisting of a command deviation, corresponding to a difference between the linear command at the output of the CO regulator and the saturated command, i.e. the command actually injected at the input of the TMH hybrid turbomachine.

[0059] The command gap allows the CO regulator to not continue to increment commands which are already at the limit.

[0060] To allow the CO regulator controls to be constrained after the synthesis, the solution proposed by the invention consists of modulating the saturation of the controls.

[0061] The CO regulator is designed to integrate the feedback from the saturated control, thus allowing the controls to be adjusted to the actual saturation. The non-saturated controls then compensate for the missing dynamics during a change in saturation.

[0062] Figure 3 shows the effect of managing the hybridization rate by control saturation according to an embodiment of the invention in the case of a dual-body / dual-flow hybrid turbomachine.

[0063] Figure 3 shows more precisely: - a temporal evolution of the regime of the high-pressure body 301 of the turbomachine in response to an instruction 302; - a time evolution of the fuel flow control 303 for different saturation values ​​of the electric torque control; and - a time evolution of the electric torque control 304 for different dynamic saturation values.

[0064] In other words, the time evolution of the electric torque control 304 shows the effect of over-constraining the electric torque control to reduce the share of electric energy in the hybridization rate.

[0065] Note that Figure 3 shows that the regulator provides the same dynamics in transient mode for speed monitoring, but that the hybridization rate is modified. Thus, the electric torque is constrained and the fuel flow plays a larger role in ensuring that the closed loop dynamic objectives are met.

[0066] According to one embodiment, the dynamic saturation law of the electric torque control is constructed from a fuzzy controller or corrector. A fuzzy controller or corrector makes it possible to describe a set of rules to constrain the behavior to be adopted with regard to the targeted hybridization rate.

[0067] According to one embodiment of the invention, the management of the constraint, or dynamic saturation law, is carried out using a set of rules relating to an electrical parameter and a motor parameter.

[0068] Figure 4 shows an example of fuzzy rules and linguistic parameters for constraining the level of hybridization according to one embodiment of the invention.

[0069] Figure 4 therefore illustrates an example of a fuzzy controller or corrector constructed from the battery charge level and an exhaust gas temperature, also known by the acronym EGT for “Exhaust Gas Temperature” in English.

[0070] In case of low batteries, the controller or fuzzy corrector will seek to limit the use of power injection, but will favor the use of electrical extraction to allow recharging.

[0071] In case of full batteries, the controller or fuzzy corrector will tend to allow more power injection to limit temperature rises, but will limit the power injection with regard to this objective if the battery level is not sufficiently high, to focus on assistance in acceleration.

[0072] Another rule will also limit the amount of charging taken to an average level if the engine temperature is very high.

[0073] The linguistic parameters are described here according to Gaussian laws.

[0074] The example shown in Figure 4 converts linguistic values ​​into numerical values ​​using a Mean of Maximum defuzzification method, also known as MoM.

[0075] By using a fuzzy controller or corrector, it is possible to favor certain modes of use of the turbomachine.

[0076] For example, during a deceleration phase, if the engine is old and has degraded efficiency, with a high temperature, the fuel flow injection will be limited to protect the engine temperatures.

[0077] Similarly, if the engine is cold and the battery is empty, it will be considered to recharge the battery to the maximum.

[0078] If the engine is hot and the battery is empty, it will be considered to recharge the battery with limited power to avoid excessive dosage of fuel in the combustion chamber, also called excess "overfuel", which can lead to overtemperature, which is an effect that it is desired to limit.

[0079] During an acceleration phase, if the battery is charged, it will be considered to allow a large electric assistance of the engine, which requires less overfuel and allows to gain in engine life.

[0080] On the contrary, if the battery is empty, it will be necessary to consider ensuring acceleration with fuel flow injection, since electric energy will not allow the desired acceleration to be obtained.

[0081] In other words, a fuzzy controller or corrector according to Figure 4 takes into account at least one electrical parameter and / or at least one engine parameter. In particular, the fuzzy controller or corrector according to Figure 4 takes as input the battery level, the exhaust gas temperature and usage rules.

[0082] The battery level can be described with Gaussian laws or straight lines.

[0083] The rules of use are based on the laws of fuel flow saturation and electric torque.

[0084] The inputs are associated with commands and are converted / translated into mathematical laws by the controller or fuzzy corrector.

[0085] The embodiment of the control method 100 using a fuzzy controller or corrector is particularly advantageous for a user who has no knowledge of automation but who is familiar with the engine, for example a thermodynamicist. The thermodynamicist will describe the operation of the machine with states.

[0086] Figure 5 and Figure 6 show, respectively, an injection authorization law and a sampling authorization law as a function of an engine parameter and an electrical parameter according to an embodiment of the invention.

[0087] Figure 5 illustrates the injection authorization law as a function of exhaust gas temperature and battery level. The injection authorization law in Figure 5 was constructed using the fuzzy controller or corrector according to Figure 4.

[0088] Figure 5 shows that injection is favored when the battery is charged and the exhaust gas temperature is not too close to the limit values.

[0089] Figure 6 illustrates the sampling authorization law as a function of exhaust gas temperature and battery level. The sampling authorization law in Figure 6 was constructed using the fuzzy controller or corrector according to Figure 4.

[0090] Figure 6 shows that sampling is favored when the battery is not fully charged and the exhaust gas temperature is not too close to the limit values.

[0091] According to another embodiment, the fuzzy controller or corrector uses linguistic parameters described by non-Gaussian laws and a “centroid” type method.

[0092] According to another embodiment, the dynamic saturation law is expressed by interpolation.

[0093] Figure 7 shows an example of the evolution of injection and power extraction constraints as a function of the input parameters.

[0094] More particularly, figure 7 shows: an evolution of the charge level of a battery 701 of a hybrid turbomachine; - an evolution of the temperature of the exhaust gases 702; - an evolution of the power injection authorization law 703 calculated using a fuzzy controller or corrector; and - an evolution of the power withdrawal authorization law 704 calculated using a fuzzy controller or corrector.

[0095] Figure 8 illustrates a schematic representation of a hybridized turbomachine 800, of the double body / double flow type according to the example presented, with a variable hybridization rate implementing the method 100 for controlling the hybridization rate according to the invention.

[0096] The hybridized turbomachine 800 comprises a propulsion system comprising a fan 801, a low-pressure shaft, a high-pressure compressor 803, a combustion chamber 804, a high-pressure shaft, a high-pressure turbine 805 and a low-pressure turbine 806.

[0097] The hybrid turbomachine 800 further comprises a low-pressure electric machine 807, connected to the low-pressure shaft, and a high-pressure electric machine 808 connected to the high-pressure shaft.

[0098] In addition, the low-pressure electric machine 807 and the high-pressure electric machine 808 are connected to the propulsion system.

[0099] Furthermore, the hybrid turbomachine 800 may comprise a reducer 802, in particular arranged between the fan 801 and the high-pressure compressor 803.

[0100] The hybridized turbomachine 800 further comprises calculation means configured for implementing the control method 100 according to the invention.

[0101] Such calculation means comprise, for example, a corrector or regulator for implementing a control loop. In addition, the calculation means may also comprise a controller for determining saturations during the step of determining the electrical torque control saturation 102 of the control method 100 according to the invention.

[0102] According to one embodiment, the calculation means of the hybridized turbomachine 800 may comprise a fuzzy controller or corrector for determining the dynamic saturation law of the electric torque control.

[0103] The hybridized turbomachine 800 according to the invention can, thanks to the implementation of the control method 100 according to the invention, vary the electric torque / fuel flow hybridization rate.

[0104] The hybridization rate of the hybridized turbomachine 800 according to the invention can be determined from an electrical parameter and an engine parameter. For example, the hybridization rate can be determined from the charge level of a battery and the temperature of the exhaust gases.

Claims

CLAIMS

1. Method for controlling (100) the hybridization rate of a hybridized turbomachine, the control method (100) comprising at least: - a step of determining the saturation of the electric torque control (102), from a first static saturation law (SS) and a first dynamic saturation law (SD), the dynamic saturation law (SD) being in particular defined from a targeted hybridization rate (TH); - a fuel flow control saturation determination step (103); - a step of determining an electric torque control and a fuel flow control (105) using a corrector (CO) taking into account at least: o a difference between the engine speed to be reached (RA) and the engine speed in place (RP), o the saturation of the electric torque control (SE) and o the saturation of the fuel flow control (SC), so as to obtain the targeted hybridization rate (TH).

2. Control method (100) according to the preceding claim, characterized in that the dynamic saturation law (SD) comprises an over-constraint of the protection saturation of the electric torque control. [Claim s] Control method (100) according to one of the preceding claims, characterized in that the dynamic saturation law of the electric torque control is constructed from a fuzzy controller, in particular taking into account at least one electrical parameter and / or at least one motor parameter.

4. Control method (100) according to the preceding claim, characterized in that the electrical parameter is the charge level of a battery connected to an electric machine of the hybridized turbomachine and / or the engine parameter is the temperature of the exhaust gases of the hybridized turbomachine. [Claim s] Control method (100) according to claim 3 or 4, characterized in that the fuzzy controller uses linguistic parameters described by Gaussian laws and a defuzzification method of the “Average of maxima” type. [Claim s] Control method (100) according to claim 3 or 4, characterized in that the fuzzy controller uses linguistic parameters described by non-Gaussian laws and a “centroid” type method.

7. Control method (100) according to one of the preceding claims, characterized in that it comprises at least: - a reception step (101), during which an engine speed setpoint to be reached is received; - a step of determining the gap (104), during which a gap between the engine speed to be reached and the engine speed in place is determined. [Claim s] Control method (100) according to one of the preceding claims, characterized in that the determination of the saturation of the electric torque control is carried out by choosing the smallest saturation from among the static saturation (SS) and the dynamic saturation (SD).

9. Control method (100) according to claim 1, characterized in that the dynamic saturation law (SD) is expressed by interpolation.

10. Hybridized turbomachine (800) with variable hybridization rate comprising the following elements: - a propulsion system (801, 802, 803, 804, 805, 806), having, at input, a fuel flow control; - an electric machine (807, 808), connected to the propulsion system and having an electric torque control as input; and - computing means configured to determine the fuel flow control and the electric torque control by implementing the control method (100) according to any one of the preceding claims.

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