Method for testing a hybrid propulsion system in an aircraft, corresponding computer program and corresponding aircraft

Description

[0001] The present invention relates to a method for testing a hybrid power plant equipping a rotary wing aircraft. Such a hybrid power plant is equipped with at least one thermal engine and at least one electric motor.

[0002] In particular, a rotorcraft may be equipped with such a hybrid power plant to rotate at least one lift rotor, possibly via at least one power transmission box.

[0003] An electric motor may take the form of an electric machine capable of operating only in a motor mode during which this electric machine provides mechanical power, or of an electric machine capable of operating in such an electric motor mode and alternatively in an electric generator mode during which this electric machine generates and provides electrical energy. Such an electric motor is usually electrically connected to a source of electrical energy. The source of electrical energy may comprise a plurality of electrical accumulators arranged in one or more electric batteries. An electric accumulator is also sometimes referred to as a cell.

[0004] A heat engine is an internal combustion engine with a combustion chamber powered by fuel and an oxidizer, such as a turboshaft engine or a piston engine.

[0005] For example, a rotorcraft may have a thermal engine and an electric motor, each capable of driving a lift rotor. The electric motor may, in particular, have the function of providing mechanical power to the lift rotor in the event of a thermal engine failure. Such a rotorcraft then combines the advantages of a single-engine rotorcraft, while offering the safety level of a twin-engine rotorcraft thanks to the assistance provided by the electric motor in the event of a thermal engine failure. The electric motor can in fact provide mechanical power to the lift rotor, following the thermal engine failure, for a period of several minutes. This mechanical power input can allow the rotorcraft to reach a safe landing area.When flying over a city, such a hybrid powerplant can increase safety for people by possibly allowing the rotorcraft to reach a landing area located outside the city, for example.

[0006] The use of an electric motor within an aircraft power plant is therefore interesting, in particular to optimize the safety of the aircraft in the event of a thermal engine failure. However, this electric motor requires the use of an electrical network electrically connected to the electric motor. This electrical network is in particular sized to provide the electric motor with the necessary electrical power so that the electric motor provides the desired mechanical power to carry out the intended mission. The electrical network of a rotorcraft with a hybrid engine is, for example, sized so that the electric motor provides a predetermined mechanical power for at least a predetermined duration in the event of a thermal engine failure. Such an electrical network is however likely to be deficient and not allow the electric motor to perform the desired function.

[0007] Document WO2020 / 156079 A1 describes a method and a device for monitoring an electric battery of an aircraft. This method comprises acquiring values ​​of performance parameters of the electric battery, these parameters comprising at least a number of operating cycles, the smallest electrical voltage across a cell of the electric battery, and a difference between electrical voltages across the cells of the electric battery. The difference between electrical voltages across the cells of the electric battery is measured between the electrical voltage of the cell of the electric battery having the greatest electrical voltage across its terminals and the electrical voltage of the cell of the electric battery having the smallest electrical voltage across its terminals.

[0008] The method comprises a step of determining a state identifier as a function of the values ​​of the performance parameters, the aircraft being controlled in flight to follow a strategy which is a function of this state identifier.

[0009] WO2018 / 171495 describes a battery management system. A management chip calculates health information for a battery cell module based on electrical current, electrical voltage, and temperature data.

[0010] Documents US 2014 / 117148 A1, US 2020 / 331621 A1, EP 3865 677 A1, and US 2015 / 176488 A1 are known and distant from the invention.

[0011] The present invention therefore aims to propose a method for testing a hybrid power plant aimed at guaranteeing the safety of a flight carried out by an aircraft equipped with this hybrid power plant. More specifically, the invention makes it possible to test the availability of mechanical power capable of being supplied by an electric motor, in particular to compensate for a breakdown of a thermal engine of the hybrid power plant.

[0012] The invention therefore relates to a method for testing a hybrid power plant equipping a rotary wing aircraft comprising at least one lift rotor, the hybrid power plant being configured to drive said at least one lift rotor in rotation, the hybrid power plant comprising: at least one heat engine configured to rotate said at least one lift rotor, and at least one electric motor supplied with electrical energy by at least one electrical power source, said at least one electric motor being configured to rotate said at least one lift rotor at least during a failure of at least one of said at least one heat engine.

[0013] According to the invention, such a method is remarkable in that it comprises a first test carried out on the ground comprising the following steps: starting said at least one heat engine, controlling a fuel supply to said at least one heat engine, the control of the fuel supply being configured so that a rotation speed NR of said at least one lift rotor reaches a first threshold speed V1, when the rotation speed NR of said at least one lift rotor is greater than or equal to the first threshold speed V1, first controlling an electrical supply to said at least one electric motor, the first controlling of the electrical supply being configured so that the rotation speed NR of said at least one lift rotor reaches a second threshold speed V2 greater than the first threshold speed V1, the first controlling of the electrical supply being carried out according to a predetermined control profile,determination of a first duration D1 taken by said at least one lift rotor to pass from the first threshold speed V1 to the second threshold speed V2, and verification that the first duration D1 is less than a predetermined threshold duration Ds.,

[0014] In other words, such a first test is carried out before the aircraft takes off. The thermal engine can be started by a pilot, a crew member or a maintenance operator, for example, by actuating a start control. Optionally, another control can then be actuated to control an idle mode allowing the thermal engine to run at an idle speed. In this idle mode, the electric motor is driven in rotation and then operates like an electric machine in generator mode, for example, to recharge said at least one electrical power source with electrical energy.

[0015] Idle mode is implemented by a supervisory system which, for example, controls the flow rate of a fuel pump and thus supplies fuel to the thermal engine(s) so that they operate at their idle speed.

[0016] At this idle speed of the thermal engine(s), the rotation speed NR of said at least one lift rotor can thus reach the first non-zero threshold speed V1.

[0017] For example, the first threshold speed V1 may be between 70% and 80% of a nominal rotation value NRnom, for example corresponding to a rotation speed allowing a predetermined nominal flight phase to be carried out. The second threshold speed V2 may be between 95% and 100% of this nominal rotation value NRnom.

[0018] From the moment when the first threshold speed V1 is reached, the heat engine can then be maintained with a fuel supply allowing stabilized operation of the heat engine and the first control of the electrical supply of said at least one electric motor is then implemented so as to increase the rotation speed NR of said at least one lift rotor up to a second threshold speed V2 greater than the first threshold speed V1.

[0019] Such a first control of the electrical supply is carried out by the supervisory system of the hybrid power plant according to the predetermined control profile, for example according to an affine function of an electrical voltage or a supply current as a function of a time variable and parameters stored in a memory of the supervisory system.

[0020] The electric motor(s) are then requested to operate with a nominal power according to the predetermined control profile to detect potential malfunctions, or a drop in performance of the electric motor(s).

[0021] The first duration D1 taken by the electric motor(s) to turn the lift rotor(s) at speed V2 is then compared with the predetermined threshold duration Ds. When the first duration D1 is less than the predetermined threshold duration Ds, the test is validated and the aircraft can then possibly begin its mission or carry out an additional test, if necessary.

[0022] On the other hand, if the first duration D1 is greater than or equal to the predetermined threshold duration Ds, the test has failed and the hybrid power plant can be stopped.

[0023] For example, such a predetermined threshold duration Ds may advantageously be between 2 s (second) and 4 s (second).

[0024] Furthermore, this predetermined threshold duration Ds must be chosen to be long enough to avoid the formation of significant mechanical torque jolts on the dynamic assemblies of the helicopter and also to avoid possible induced yaw movements.

[0025] Such a test method may further include one or more of the following features, taken alone or in combination.

[0026] Furthermore, the first control of the electrical power supply of said at least one electric motor may comprise at least one regulation loop so that the rotation speed NR of the lift rotor(s) reaches the second threshold speed V2.

[0027] According to a first exemplary embodiment of the invention, the first control of the electrical power supply of said at least one electric motor may comprise a first torque regulation relating to a motor torque supplied by said at least one electric motor.

[0028] In other words, according to this first example, we can measure the motor torque supplied by said at least one electric motor and compare it with a torque setpoint to carry out a torque control loop in order to regulate the first command of the electrical supply.

[0029] Such a torque setpoint then varies from a zero or minimum torque setpoint to a maximum torque setpoint allowing the lifting rotor(s) to rotate at the rotation speed NR greater than or equal to the second threshold speed V2.

[0030] According to a second exemplary embodiment of the invention, the first control of the electrical power supply to said at least one electric motor may comprise a second speed regulation relative to a rotation speed of a member of a kinematic transmission chain connecting said at least one electric motor to said at least one lift rotor.

[0031] According to the second example, the rotational speed of a component of a transmission kinematic chain can be measured and compared with a speed setpoint in order to implement a speed control loop in order to regulate the first command of the electrical supply.

[0032] Such a speed setpoint then varies from a zero or minimum speed setpoint to a maximum speed setpoint allowing the lifting rotor(s) to rotate at the rotation speed NR greater than or equal to the second threshold speed V2.

[0033] According to a third exemplary embodiment of the invention, the first control of the electrical power supply of said at least one electric motor may comprise a third power regulation relating to a driving power supplied by said at least one electric motor.

[0034] Finally, according to this third example, it is also possible to determine or calculate the driving power supplied by said at least one electric motor and then compare it with a power setpoint so as to implement a power control loop in order to regulate the first command of the electrical power supply.

[0035] Such a power setpoint then varies from a zero or minimum power setpoint to a maximum power setpoint allowing the lifting rotor(s) to rotate at the rotation speed NR greater than or equal to the second threshold speed V2.

[0036] Furthermore, the first control of the power supply of said at least one electric motor can be implemented in different ways.

[0037] According to a first variant of the invention, the first control of the electrical power supply of said at least one electric motor can be implemented automatically by a supervisory system.

[0038] Consequently, according to this first variant, the first test can be implemented automatically after starting the thermal engine(s), or even after each start. In this case, this first test can be triggered directly by the supervisory system without the pilot actuating a control device.

[0039] According to a second variant of the invention, the first control of the electrical power supply of said at least one electric motor can be implemented under the dependence of a control instruction transmitted by a control member to a supervisory system, the control member making it possible to collectively control a blade pitch of said at least one lift rotor.

[0040] In this case, the modification of the electrical power supply of said at least one electric motor allowing the increase of the rotation speed NR from the first threshold speed V1 to the second threshold speed V2 can be controlled by the pilot using a control lever of a blade pitch of said at least one lift rotor varying collectively.

[0041] Optionally, the kinematic chain for controlling the collective pitch of the blades may include speed limitations to protect components of the aircraft and in particular dynamic assemblies of this aircraft such as a main power transmission box and said at least one lift rotor.

[0042] In practice, the first command of the electrical power supply of said at least one electric motor can be triggered by a pilot by a selection of a predetermined mode, the selection being implemented by means of a first human-machine interface.

[0043] In other words, the mode selected by the pilot can be a test mode aimed at launching at least the test process and then returning to the initial mode preceding this selection of the test mode.

[0044] Thus, if the test mode is selected by the pilot, once the test method has been carried out, the electrical power supply to said at least one electric motor can be cut off and the rotation speed NR can automatically decrease from the second threshold speed V2 to the first threshold speed V1. The supervisor system can then implement the idling mode of the thermal engine if the test is validated, or can alternatively cut off the fuel supply to the thermal engine if the test has failed.

[0045] Additionally, when the first test fails, the supervisory system can optionally inform the pilot with an audible or visual alarm. The pilot can then decide to take off to carry out his mission with limitations related to the fact that the first test is not validated.

[0046] Alternatively, the mode selected by the pilot may be a flight mode intended to firstly launch the test process and then secondly to implement the flight mode as such which is different from the initial mode preceding this selection of the flight mode.

[0047] Thus when the flight mode is selected by the pilot, once the test method has been carried out, the electrical power supply to said at least one electric motor can be cut off. However, the rotation speed NR can be maintained greater than or equal to the second threshold speed V2 by a new control of the fuel supply to said at least one thermal engine.

[0048] In addition, the supervisory system can then implement flight mode if the test is validated or can alternatively cut off the fuel supply to the thermal engine if the test has failed.

[0049] Furthermore, the first human-machine interface for selecting the predetermined mode may be a control button, a keyboard, a pointing device on a screen or even a touch control interface.

[0050] Advantageously, the first test is validated, the process can include at least one other additional test.

[0051] Thus, the method may include a second test comprising the following steps: when the rotation speed NR of said at least one lift rotor is greater than or equal to the second threshold speed V2, second control of an electrical power supply of said at least one electric motor, the second control of the electrical power supply being configured to maintain the rotation speed NR of said at least one lift rotor greater than or equal to the second threshold speed V2 for a second predetermined duration D2, calculation of an electrical power Pe supplied by said at least one electrical power source to said at least one electric motor for the second predetermined duration D2, and identification that said electrical power Pe is stable for the second predetermined duration D2 by being between a lower predetermined threshold power Psinf and an upper predetermined threshold power Pssup.

[0052] Such an electrical power Pe thus corresponds to the total power supplied to said at least one electric motor by said at least one electrical power source during this second predetermined duration D2. Such an electrical power Pe can in particular be calculated from an electrical current supplied to said at least one electric motor by said at least one electrical power source during this second predetermined duration D2.

[0053] The electrical power Pe supplied by said at least one electrical power source to maintain the lift rotor(s) at speed V2 for the second predetermined duration D2 is then compared with the lower predetermined threshold power Psinf and the upper predetermined threshold power Pssup. When the electrical power Pe is substantially constant for the second predetermined duration D2 while being greater than the lower predetermined threshold power Psinf and less than the upper predetermined threshold power Pssup, the second test is validated and the aircraft can then possibly begin its mission or carry out an additional test, if necessary.

[0054] On the other hand, if the electrical power Pe is not stable and does not remain between the lower predetermined threshold power Psinf and a higher predetermined threshold power Pssup, the second test has failed and the hybrid power plant can be stopped, for example.

[0055] Alternatively, when the second test has failed, the supervisor system can optionally inform the pilot by an audible or visual alarm.

[0056] When this second test is carried out on the ground, the pilot can then decide to take off to carry out his mission with limitations linked to the fact that the second test has not been validated.

[0057] When this second test is carried out in flight, the pilot can then decide to complete his current mission with limitations linked to the fact that the second test is not validated.

[0058] By way of example, such an electrical power Pe supplied by said at least one electrical power source during the second predetermined duration D2 may advantageously be between 50 kW (kilowatt) and 100 kW (kilowatt). According to this example, the lower predetermined threshold power Psinf may then be equal to 49 kW (kilowatt) and the upper predetermined threshold power Pssup may then be equal to 101 kW.

[0059] For example, such a second predetermined duration D2 may advantageously be between 0.5 s (second) and 2 s (second).

[0060] According to a first embodiment of the invention, the second test can be triggered by a pilot by a selection implemented by means of a second human-machine interface.

[0061] As with the first human-machine interface, the second human-machine interface can be a control button, a keyboard, a pointing device on a screen or even a touch control interface.

[0062] Furthermore, the first human-machine interface and the second human-machine interface may be separate from each other or alternatively be combined to form a single human-machine interface.

[0063] According to a second embodiment of the invention, the second test can be carried out automatically following the first test.

[0064] In this case, the second test can be triggered without any special action from the driver. Thus, no human-machine interface is used to select the second test. Optionally, and if the first test is validated, a predetermined delay of, for example, a few seconds can be implemented by the supervisory system between the end of the first test and the start of the second test.

[0065] In practice, the second test can be carried out on the ground.

[0066] Thus, once the first test has been carried out and validated, the second test can be triggered before the aircraft takes off.

[0067] Alternatively, the second test can be carried out during a flight phase of the aircraft.

[0068] In this case, the second test can be implemented after takeoff of the aircraft and therefore during a flight phase of the aircraft during a hybridization phase of the hybrid power plant using said at least one electric motor.

[0069] The present invention also relates to a computer program configured to be implemented in a rotary wing aircraft comprising at least one lift rotor and a hybrid power plant, the hybrid power plant being configured to drive said at least one lift rotor in rotation, the hybrid power plant comprising: at least one heat engine configured to rotate said at least one lift rotor, and at least one electric motor supplied with electrical energy by at least one electrical power source, said at least one electric motor being configured to rotate said at least one lift rotor at least during a failure of at least one of said at least one heat engine.

[0070] According to the invention, the computer program is remarkable in that it comprises a sequence of instructions executable by a supervisory system connected to the hybrid power plant, the supervisory system implementing the aforementioned hybrid power plant testing method.

[0071] Such a computer program is then advantageously stored in a storage unit of the supervisor system.

[0072] The invention also relates to a rotary wing aircraft comprising at least one lift rotor and a hybrid power plant, the hybrid power plant being configured to drive said at least one lift rotor in rotation, the hybrid power plant comprising: at least one heat engine configured to rotate said at least one lift rotor, and at least one electric motor supplied with electrical energy by at least one electrical power source, said at least one electric motor being configured to rotate said at least one lift rotor at least during a failure of at least one of said at least one heat engine.

[0073] According to the invention, the aircraft is remarkable in that it comprises a supervisory system connected to the hybrid power plant, the supervisory system implementing the aforementioned hybrid power plant testing method.

[0074] Consequently, such an aircraft carries on board a supervisory system capable of carrying out at least the first test, and possibly also the second test.

[0075] The invention and its advantages will appear in more detail in the context of the description which follows with examples given for illustrative purposes with reference to the appended figures which represent: there figure 1 , a diagram illustrating a mission of an aircraft according to the invention, the figure 2 , a flowchart illustrating a first example of a method for testing a hybrid power plant in accordance with the invention, the figure 3 , a flowchart illustrating a second example of a method for testing a hybrid power plant in accordance with the invention, the figure 4 , curves representative of the controls of the hybrid power plant implemented during a test method in accordance with the invention, the figure 5 , a diagram illustrating a first example of an aircraft in accordance with the invention, and the figure 6 , a diagram illustrating a second example of an aircraft in accordance with the invention.

[0076] Elements present in several distinct figures are assigned a single reference.

[0077] There figure 1 presents an aircraft 1 according to the invention. This aircraft 1 is equipped with a hybrid power plant 10. The hybrid power plant 10 comprises at least one thermal engine 15 and at least one electric motor 20 which are both capable of setting in motion at least one lift rotor 2, or even only one thermal engine 15 and one electric motor 20. Such at least one lift rotor 2 may have the function of participating in the advancement and / or propulsion of the aircraft 1. This at least one lift rotor 2 thus comprises at least one blade 5.

[0078] For example, the thermal engine 15 is in operation by default, the electric motor 20 having the function of compensating for a breakdown of the thermal engine 15.

[0079] On a conventional single-engine aircraft, following a failure 96 of the thermal engine, the aircraft performs a descent 97. For example, a helicopter performs a so-called "autorotation" flight. When flying over an urban area 95, the aircraft is likely to head towards this area.

[0080] With an aircraft 1 according to the invention equipped with a hybrid power plant 10, following the breakdown 96, the electric motor 20 takes over from the thermal engine 15 and sets the lift rotor(s) 2 in motion. For a certain duration, the aircraft 1 can continue its flight during an electrically powered flight phase 98, then perform a descent 99. For example, the aircraft 1 performs a so-called “autorotation” flight during the descent 99. When flying over an urban area 95, the aircraft 1 is likely to move away from this urban area to reach a safe zone 100 to perform a landing.

[0081] An aircraft 1 according to the invention allows a pilot to ensure that the electric motor system is functional before takeoff, or even during a flight phase.

[0082] As represented in the figure 2 , a first example of a method 50 for testing the hybrid power plant 10 comprises a first test 51 carried out on the ground comprising, in a first step, a start 52 of the thermal engine(s) 15 and a control of a fuel supply 53 of the thermal engine(s) 15 to increase a rotation speed NR of the lift rotor(s) 2 up to a first threshold speed V1.

[0083] In a second step, when the rotation speed NR of the lift rotor(s) 2 is greater than or equal to the first threshold speed V1, the first test 51 then comprises a first command of an electrical power supply 54, 54', 54" of the electric motor(s) 20 to increase the rotation speed NR of the lift rotor(s) 2 up to a second threshold speed V2 greater than the first threshold speed V1.

[0084] Furthermore, this first control of the power supply 54, 54', 54" is carried out for example according to a predetermined control profile as shown in figure 4 Such a predetermined control profile is in fact illustrated during a phase P2 of the curve C2 representative of the motor torque supplied by the electric motor(s) 20 as a function of time.

[0085] Such a first control of the electrical power supply 54, 54', 54" of the electric motor(s) 20 is further implemented by means of a supervisory system 3, 3' on board the aircraft 1. This first control of the electrical power supply 54, 54', 54" may for example be automatic in the case of the supervisory system 3 or alternatively, as shown in figure 5 , depending on a control instruction transmitted by a control member 4 to the supervisor system 3'. Such a control member 4 is configured to collectively control a pitch of the blade(s) 5 of the lift rotor(s) 2.

[0086] The supervisor system 3, 3' may comprise, for example, at least one processor and at least one memory, at least one integrated circuit, at least one programmable system, at least one logic circuit, these examples not limiting the scope given to the expression "supervisor system". The term processor may also designate a central processing unit known by the acronym CPU, a graphics processing unit GPU, a digital unit known by the acronym DSP, a microcontroller, etc.

[0087] Furthermore, the supervisor system 3, 3' makes it possible to execute a computer program in accordance with the invention comprising a sequence of instructions implementing the method 50 for testing the hybrid power plant 10.

[0088] According to a first exemplary embodiment of the invention, this first control of the electrical power supply 54 of the electric motor(s) 20 may comprise a first torque regulation relating to a motor torque supplied by the electric motor(s) 20.

[0089] According to a second exemplary embodiment of the invention, the first control of the electrical power supply 54' of the electric motor(s) 20 may comprise a second speed regulation relative to a rotation speed of a member of a kinematic transmission chain connecting the electric motor(s) 20 to the lift rotor(s) 2.

[0090] And according to a third exemplary embodiment of the invention, the first control of the electrical power supply 54" of the electric motor(s) 20 may comprise a third power regulation relating to a driving power supplied by the electric motor(s) 20.

[0091] The first test 51 then comprises a determination 55 of a first duration D1 taken by the lift rotor(s) 2 to go from the first threshold speed V1 to the second threshold speed V2, then a verification 56 that this first duration D1 is less than a predetermined threshold duration Ds.

[0092] As represented in the figure 3 , a second example of method 60 for testing the hybrid power plant 10 comprises, in addition to the first test 51 mentioned above, a second test 61, 61'.

[0093] This second test 61, 61' then comprises, when the rotation speed NR of the lift rotor(s) 2 is greater than or equal to the second threshold speed V2, a second command of an electrical power supply 62 of the electric motor(s) 20. Such a second command of the electrical power supply 62 is configured to maintain the rotation speed NR of the lift rotor(s) 2 greater than or equal to the second threshold speed V2 for a second predetermined duration D2.

[0094] The second test 61, 61' then comprises a calculation 63 of an electrical power Pe supplied by the electrical power source(s) 21 to the electric motor(s) 20 during the second predetermined duration D2 and finally an identification 64 that the electrical power Pe is substantially stable and between a lower predetermined threshold power Psinf and an upper predetermined threshold power Pssup.

[0095] Furthermore, the supervisor system 3, 3' can also make it possible to execute a computer program comprising a sequence of instructions implementing the method 60 for testing the hybrid power plant 10.

[0096] As represented in the figure 4 , curve C1 is representative of the rotation speed NR of the lift rotor(s) 2 as a function of time for successive phases P1, P2, P3 and P4.

[0097] Curve C2 is representative of the engine torque supplied by the electric motor(s) 20 to drive the lift rotor(s) 2 as a function of time during the same successive phases P1, P2, P3 and P4.

[0098] Curve C3 is representative of the electrical power supplied by the electric motor(s) 20 to drive the lift rotor(s) 2 as a function of time during the same successive phases P1, P2, P3 and P4.

[0099] Finally, curve C4 is representative of a control instruction for a collective pitch of the blades 5 of the lift rotor(s) 2 as a function of time during the same successive phases P1, P2, P3 and P4.

[0100] As represented in the figure 6 , the first control of the electrical power supply 54, 54', 54" of the electric motor(s) 20 can be triggered by a pilot by a selection of a predetermined mode. Such a selection can be implemented by means of a first human-machine interface 6 formed for example by a button, a pointing device or a touch control interface.

[0101] The first human-machine interface 6 is then connected to the supervisor system 3, 3' to enable the first control of the electrical power supply 54, 54', 54" of the electric motor(s) 20 to begin according to the predetermined mode selected.

[0102] Such a predetermined mode may be, for example, a test mode aimed, for example, at carrying out the first test 51 then stopping the first command of the electrical power supply 54, 54', 54" of the electric motor(s) 20 or a flight mode making it possible, for example, to carry out the first test 51 and the second test 61, 61' before allowing takeoff of the aircraft 1 if the two tests are validated.

[0103] Likewise, the second test 61 can be triggered by a driver by a selection implemented by means of a second human-machine interface 7. Such a second human-machine interface 7 can also be formed, for example, by a button, a pointing device or a touch control interface.

[0104] Furthermore, this second human-machine interface 7 may be separate or confused with the first human-machine interface 6.

[0105] Alternatively, the second test 61' can be triggered automatically following validation of the first test 51.

[0106] In any event, if one of the tests 51, 61, 61' is not validated, the supervisor system 3, 3' can order either a shutdown of the hybrid power plant 10 in the case where the aircraft 1 is on the ground, or an alert aimed at informing the pilot of a problem in the case where the aircraft 1 is in flight.

[0107] In this second case, the pilot may then be forced to abandon his mission, return to a base or even make an emergency landing.

[0108] Naturally, the present invention is subject to numerous variations in its implementation. Although several embodiments have been described, it is understood that it is not conceivable to exhaustively identify all possible embodiments.

Claims

1. Method (50) for testing a hybrid power plant (10) equipping a rotary-wing aircraft (1) comprising at least one lift rotor (2), said hybrid power plant (10) being configured to rotate said at least one lift rotor (2), the hybrid power plant (10) comprising: • at least one heat engine (15) configured to rotate said at least one lift rotor (2), and • at least one electric motor (20) supplied with electrical energy by at least one electrical power source (21), said at least one electric motor (20) being configured to rotate said at least one lift rotor (2) at least when at least one of said at least one heat engines (15) fails, characterized in that said method (50, 60) comprises a first test (51) performed on the ground comprising the following steps: • starting (52) said at least one heat engine (15), • controlling a supply of fuel (53) to said at least one heat engine (15), said control of the supply of fuel (53) being configured so that a speed of rotation NR of said at least one lift rotor (2) reaches a first threshold speed V1, • when said speed of rotation NR of said at least one lift rotor (2) is greater than or equal to said first threshold speed V1, first control of a supply of power (54, 54', 54") to said at least one electric motor (20), the first control of the supply of power (54, 54', 54") being configured so that the speed of rotation NR of said at least one lift rotor (2) reaches a second threshold speed V2 greater than said first threshold speed V1, said first control of the supply of power (54, 54', 54") being carried out according to a predetermined control profile, • determining (55) a first period of time D1 taken by said at least one lift rotor (2) to shift from said first threshold speed V1 to said second threshold speed V2, and • checking (56) that said first time period D1 is less than a predetermined threshold time period Ds.

2. Method according to Claim 1, characterized in that said first control of the supply of power (54) to said at least one electric motor (20) comprises a first torque regulation relative to an engine torque supplied by said at least one electric motor (20).

3. Method according to Claim 1, characterized in that said first control of the supply of power (54') to said at least one electric motor (20) comprises a second speed regulation relative to a speed of rotation of a member of a transmission kinematic linkage linking said at least one electric motor (20) to said at least one lift rotor (2).

4. Method according to Claim 1, characterized in that said first control of the supply of power (54") to said at least one electric motor (20) comprises a third power regulation relative to a driving power supplied by said at least one electric motor (20).

5. Method according to any one of Claims 1 to 4, characterized in that said first control of the supply of power (54, 54', 54") to said at least one electric motor (20) is implemented automatically by a supervisor system (3).

6. Method according to any one of Claims 1 to 5, characterized in that said first control of the supply of power (54, 54', 54") to said at least one electric motor (20) is implemented depending on a control setpoint transmitted by a control member (4) to a supervisor system (3'), said control member (4) allowing a pitch of blades (5) of said at least one lift rotor (2) to be controlled collectively.

7. Method according to any one of Claims 1 to 6, characterized in that said first control of the supply of power (54, 54', 54") to said at least one electric motor (20) is triggered by a pilot selecting a predetermined mode, said selection being implemented by means of a first human-machine interface (6).

8. Method according to any one of Claims 1 to 7, characterized in that said method (60) comprises a second test (61, 61') comprising the following steps: • when said speed of rotation NR of the at least one lift rotor (2) is greater than or equal to said second threshold speed V2, second control of a supply of power (62) to said at least one electric motor (20), said second control of the supply of power (62) being configured to keep said speed of rotation NR of said at least one lift rotor (2) greater than or equal to said second threshold speed V2 for a second predetermined time period D2, • calculating (63) an electrical power Pe supplied by said at least one electrical power source (21) to said at least one electric motor (20) during said second predetermined time period D2, and • identifying (64) that said electrical power Pe is stable for the second predetermined time period D2, being between a lower predetermined threshold power Psinf and an upper predetermined threshold power Pssup.

9. Method according to Claim 8, characterized in that said second test (61) is triggered by a pilot making a selection by means of a second human-machine interface (7).

10. Method according to Claim 8, characterized in that said second test (61') is performed automatically after said first test (51).

11. Method according to any one of Claims 8 to 10, characterized in that said second test (61, 61') is performed on the ground.

12. Method according to any one of Claims 8 to 10, characterized in that said second test (61, 61') is performed during a flight phase of said aircraft (1).

13. Computer program configured to be implemented in a rotary-wing aircraft (1) comprising at least one lift rotor (2) and one hybrid power plant (10), said hybrid power plant (10) being configured to rotate said at least one lift rotor (2), said hybrid power plant (10) comprising: • at least one heat engine (15) configured to rotate said at least one lift rotor (2), and • at least one electric motor (20) supplied with electrical energy by at least one electrical power source (21), said at least one electric motor (20) being configured to rotate said at least one lift rotor (2) at least when at least one of said at least one heat engines (15) fails, characterized in that said computer program comprises a sequence of instructions that can be carried out by a supervisor system (3, 3') connected to said hybrid power plant (10), said supervisor system (3, 3') implementing said method (50, 60) for testing said hybrid power plant (10) according to Claim 1.

14. Rotary-wing aircraft (1) comprising at least one lift rotor (2) and one hybrid power plant (10), said hybrid power plant (10) being configured to rotate said at least one lift rotor (2), said hybrid power plant (10) comprising: • at least one heat engine (15) configured to rotate said at least one lift rotor (2), and • at least one electric motor (20) supplied with electrical energy by at least one electrical power source (21), said at least one electric motor (20) being configured to rotate said at least one lift rotor (2) at least when at least one of said at least one heat engines (15) fails, characterized in that said aircraft (1) comprises a supervisor system (3, 3') connected to said hybrid power plant (10), said supervisor system (3, 3') implementing said method (50, 60) for testing said hybrid power plant (10) according to Claim 1.