METHOD AND DEVICE FOR MANAGING THE ENERGY SUPPLIED BY A HYBRID POWER PLANT FOR A ROTORCRAFT

Abstract

A method for managing the energy supplied by a hybrid power plant for propelling a rotorcraft, the hybrid power plant comprising two heat engines, two electric motors and an electrical energy source. The method includes a step of acquiring at least one first characteristic of the electrical energy source and/or the electric motors and a step of determining a mechanical power requirement of the rotorcraft. The method then includes a step of determining a first power distribution between each heat engine and electric motor as a function of the first characteristic and the mechanical power requirement of the rotorcraft, then a step of controlling each heat engine and electric motor according to several operating modes, including a distributed operating mode applying the first power distribution.

Claims

1. A method for managing the energy supplied by a hybrid power plant for propelling a rotorcraft, the rotorcraft including: a hybrid power plant provided with at least one heat engine, at least one electric motor, a main gearbox, at least one electrical energy source, one control unit for each heat engine, one control device for each electric motor and at least one sensor for monitoring the electrical energy source(s) or the electric motor(s); at least one main rotor rotated by the hybrid power plant; and at least one calculator; the method comprising the following steps: acquiring at least one first characteristic of the electrical energy source(s) and/or the electric motor(s) by means of at least one sensor; determining a mechanical power requirement of the rotorcraft; determining a first power distribution between the heat engine(s) and the electric motor(s) as a function of the first characteristic(s) and the mechanical power requirement of the rotorcraft; and controlling the heat engine(s) and the electric motor(s) via the control unit(s) and the control device(s), respectively, according to a distributed operating mode, the distributed operating mode applying the first power distribution, wherein the method includes a step of determining a flight phase of the rotorcraft, the flight phase being taken into account during the step of determining the first power distribution.

2. The method according to claim 1 wherein the method comprises a step of acquiring at least one second characteristic of the rotorcraft and/or of the hybrid power plant, the second characteristic(s) being used during the step of determining a first power distribution.

3. The method according to claim 1 wherein the method includes a step of acquiring at least one second characteristic of the rotorcraft and/or of the hybrid power plant, the second characteristic(s) being used during the step of determining a mechanical power requirement of the rotorcraft.

4. The method according to claim 2 wherein the second characteristic(s) of the rotorcraft and/or the hybrid power plant is/are chosen from the following list: speed of rotation of a heat engine; temperature of a heat engine; state of health of a heat engine; speed of rotation of the main rotor; altitude of the rotorcraft; forward speed of the rotorcraft; vertical speed of the rotorcraft; value of a collective pitch control of the blades of the main rotor; and value of a cyclic pitch control of the blades of the main rotor.

5. The method according to claim 1 wherein the flight phase is chosen from a list comprising a take-off phase, a landing phase, a hovering flight phase, a level flight phase, a change of altitude phase and a maneuvering phase.

6. The method according to claim 1 wherein the step of determining a first power distribution takes into account the preservation of a backup electrical energy reserve for at least one electrical energy source.

7. The method according to claim 1 wherein the step of determining a first power distribution takes into account a flight plan of the rotorcraft such that the electrical energy source(s) no longer contain(s) any electrical energy at the end of the flight.

8. The method according to claim 1 wherein the first characteristic(s) of the electrical energy source(s) and/or the electric motor(s) is/are chosen from the following list: a state of charge of the electrical energy source(s); a depth of discharge of the electrical energy source(s); a temperature of the electrical energy source(s); a state of health of the electrical energy source(s); and a temperature of the electric motor(s).

9. The method according to claim 1 wherein the first power distribution is determined so that the electric motor(s) operate(s) in an electrical energy generator mode so as to recharge at least one electrical energy source.

10. The method according to claim 1 wherein the method comprises the following steps: selecting an operating mode to select an operating mode of the hybrid power plant by means of a selection device; and controlling the heat engine(s) and the electric motor(s) via the control unit(s) and the control device(s), respectively, according to the operating mode selected from among the following operating modes depending on the selection: the distributed operating mode; a total operating mode during which the power supplied by the hybrid power plant is increased, the heat engine(s) supplying the maximum available power and energy and the electric motor(s) supplying the maximum available power irrespective of the mechanical power requirement of the rotorcraft; and a “low-emission” operating mode applying a second power distribution between the heat engine(s) and the electric motor(s), the second power distribution limiting polluting emissions from the hybrid power plant for the environment outside the rotorcraft.

11. The method according to claim 9 wherein the total operating mode and/or the “low-emission” operating mode take(s) into account the preservation of a backup electrical energy reserve for at least one electrical energy source in the “low-emission” operating mode.

12. The method according to claim 9 wherein, according to the second power distribution, the electric motor(s) supplie(s) the maximum available energy and the heat engine(s) supplie(s) additional power depending on the mechanical power requirement of the rotorcraft.

13. The method according to claim 10 wherein the method includes a step of determining a second power distribution between the heat engine(s) and the electric motor(s) as a function of the first characteristic(s) and the mechanical power requirement of the rotorcraft.

14. The method according to claim 12 wherein the step of determining a second power distribution takes into account at least one second characteristic of the rotorcraft and/or the hybrid power plant and/or a flight phase of the rotorcraft such that the electrical energy source(s) no longer contain(s) any electrical energy at the end of the flight.

15. A hybrid power plant intended for a rotorcraft, the hybrid power plant including at least one heat engine, at least one electric motor, a main gearbox, at least one electrical energy source, one control unit for each heat engine, one control device for each electric motor and at least one sensor for monitoring the electrical energy source(s) or the electric motor(s), wherein the hybrid power plant comprises a calculator configured to implement the method according to claim 1.

16. A rotorcraft comprising the hybrid power plant and at least one main rotor rotated by the hybrid power plant and wherein the hybrid power plant is according to claim 14.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0103] The disclosure and its advantages appear in greater detail in the context of the following description of embodiments given by way of illustration and with reference to the accompanying figures, in which:

[0104] FIG. 1 is a view of a rotorcraft according to the disclosure;

[0105] FIG. 2 is an overview diagram of a method according to the disclosure; and

[0106] FIG. 3 is an overview diagram of a method according to the disclosure.

DETAILED DESCRIPTION

[0107] Elements that are present in more than one of the figures are given the same references in each of them.

[0108] FIG. 1 shows a rotorcraft 1 comprising a fuselage 4, a main lift rotor 2 and an auxiliary rotor 3 arranged at a free end of a tail boom 5. The main rotor 2 and the auxiliary rotor 3 respectively comprise a rotating hub and blades. The rotorcraft 1 also comprises a hybrid power plant 10 that rotates the main lift rotor 2 and the auxiliary rotor 3.

[0109] The hybrid power plant 10 may include at least one heat engine 11, 12, at least one electric motor 15, 17, a main gearbox 20, at least one electrical energy source 19, one control unit 13, 14 for each heat engine 11, 12, one control device 16, 18 for each electric motor 15, 17, and at least one sensor 21, 22 for monitoring each electrical energy source 19 or each electric motor 15, 17.

[0110] According to FIG. 1, the hybrid power plant 10 comprises two heat engines 11, 12, two electric motors 15, 17, a main gearbox 20, an electrical energy source 19, one control unit 13, 14 for each heat engine 11, 12, one control device 16, for each electric motor 15, 17, a sensor 21 for monitoring the electrical energy source 19 and a sensor 22 for monitoring the electric motors 15, 17.

[0111] The two heat engines 11, 12 are connected to the main gearbox 20. Each heat engine 11, 12 may, for example, have a nominal power of the order of 400 to 600 kilowatts (400 to 600 kW). These heat engines 11, 12 may, for example, be turboshaft engines or else piston engines.

[0112] A first electric motor 15 is also connected to the main gearbox 20. This first electric motor 15 may, for example, have a nominal power of the order of 100 to 300 kW. This first electric motor 15 constitutes a transient power source for the hybrid power plant 10 and has operating times in motor mode of a few dozen seconds to a few minutes, for example.

[0113] A second electric motor 17 is connected directly to one of the heat engines 11, 12. This second electric motor 17 may, for example, have a nominal power of the order of 10 to 20 kW. This second electric motor 17 has short operating times, of the order of a few seconds. This second electric motor 17 may be used, in particular, to start the heat engine 11, 12 to which it is connected and to supply it, in a transient manner, with a small amount of surplus power.

[0114] The rotorcraft 1 also includes control means 31, 32 and a selection device 35. A control stick 31 is intended to collectively modify the pitch of the blades of the main rotor 2 while a control lever 32 is intended to cyclically modify the pitch of the blades of the main rotor 2. The rotorcraft 1 also comprises a sensor 23 measuring the speed of rotation of the main rotor 2 and two sensors 24, 25 measuring the travels of the control stick 31 and of the control lever 32 respectively.

[0115] The hybrid power plant 10 also comprises a calculator configured to implement a method for managing the energy supplied by the hybrid power plant 10 for propelling the rotorcraft 1. By way of example, the calculator 9 may comprise at least one processor and at least one memory, at least one integrated circuit, at least one computer, at least one programmable system, or at least one logic circuit, these examples not limiting the scope to be given to the term “calculator”. The term “processor” may refer equally to a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), a microcontroller, etc.

[0116] The calculator 9 is thus connected by wired or wireless means to the sensors 21, 22, the control units 13, 14 and the control devices 16, 18, as well as, possibly, to the sensors 23, 24, 25.

[0117] The calculator 9 may also be hosted by a control unit 13, 14, a control device 16, 18 or else be shared with other functions of the rotorcraft 1 and be integrated, for example, into an avionics system of the rotorcraft 1.

[0118] FIG. 2 is an overview diagram of this energy management method. This method may include four main steps.

[0119] Firstly, a step 110 of acquiring at least one first characteristic of the electrical energy source 19 and/or of each electric motor 15, 17 is carried out by means of the sensors 21, 22.

[0120] A first characteristic of the electrical energy source 19 may be a state of charge of the electrical energy source 19, a depth of discharge of the electrical energy source, a temperature of the electrical energy source 19 and a state of health of the electrical energy source 19. A first characteristic of the electric motors 15, 17 may be a temperature of an electric motor 15, 17.

[0121] The first characteristics of the source 19 acquired during this acquisition step 110 can be used to define the current state of the electrical energy source 19, and to deduce therefrom the ability of the source 19 to supply electrical energy and the quantity of electrical energy that the source 19 can supply. The first characteristics of the source 19 acquired during this acquisition step 110 can also be used to define the quantity of electrical energy that each electric motor 15, 17 can use and to deduce therefrom the mechanical power that each heat engine 15, 17 can deliver.

[0122] A step 120 of determining a mechanical power requirement of the rotorcraft 1 is carried out in a conventional manner, for example as a function of the mass of the rotorcraft 1, its forward speed, its vertical speed and the values of the collective pitch and cyclic pitch controls of the blades of the main rotor 2.

[0123] The step 120 of determining a mechanical power requirement of the rotorcraft 1 is carried out, for example, by means of the calculator 9, using such information. The step 120 of determining a mechanical power requirement of the rotorcraft 1 may also be performed by an avionics system of the rotorcraft 1 or a dedicated device.

[0124] The acquisition step 110 and the determination step 120 are preferably performed in parallel. However, the acquisition step 110 and the determination step 120 may be performed sequentially.

[0125] Next, a step 140 of determining a first power distribution between the heat engines 11, 12 and the electric motors 15, 17 as a function of at least one first characteristic and the mechanical power requirement of the rotorcraft 1 is carried out by means of the calculator 9.

[0126] During this step 140 of determining the first power distribution, the first power distribution is determined on the basis of the quantity of electrical energy that the electrical energy source 19 can supply and the operating conditions of the electrical energy source 19, for example its temperature, state of health and depth of discharge. The first power distribution is determined based on the mechanical power that each electric motor 15, 17 can actually supply, taking into account, in particular, the temperature of each electric motor 15, 17 and the quantity of electrical energy available in the electrical energy source 19.

[0127] Finally, the method includes a step 150 of controlling the at least one heat engine 11, 12 and the at least one electric motor 15, 17 carried out by means of each control unit 13, 14 and each control device 16, 18, respectively, according to a distributed operating mode 160, the distributed operating mode 160 applying the first power distribution.

[0128] Next, the step 150 of controlling the two heat engines 11, 12 and the two electric motors 15, 17 is carried out by means of the two control units 13, 14 and the two control devices 16, 18, respectively, according to a distributed operating mode in order to propel the rotorcraft 1, optimizing the use of the energy available in the rotorcraft 1. The distributed operating mode applies the previously-determined first power distribution.

[0129] The method for managing the energy supplied by a hybrid power plant 10 for propelling a rotorcraft 1 according to the disclosure may comprise steps in addition to the four main steps described in FIG. 2. FIG. 3 shows an overview diagram of such an energy management method.

[0130] For example, the method according to the disclosure may include a step 130 of acquiring at least one second characteristic of the rotorcraft 1 and/or of the hybrid power plant 10. This step 130 of acquiring at least one second characteristic is, for example, carried out by means of the sensor 23 measuring the speed of rotation of the main rotor 2 and/or the sensors 24, 25 measuring the travels of the control stick 31 and of the control lever 32 respectively. Other sensors present in the rotorcraft 1 may also be used.

[0131] A second characteristic of the hybrid power plant 10 may be the speed of rotation of a heat engine 11, 12, its temperature or its state of health. A second characteristic of the rotorcraft 1 may be the speed of rotation of the main rotor 2, the altitude of the rotorcraft 1, its forward speed and its vertical speed, or else the value of a collective pitch and/or cyclic pitch control of the blades of the main rotor 2.

[0132] One or more second characteristics may be used both during the step 140 of determining a first power distribution and during the step 120 of determining a mechanical power requirement of the rotorcraft 1.

[0133] The method according to the disclosure may also comprise a step 135 of determining a flight phase of the rotorcraft 1. The flight phase may be determined conventionally based on the flight conditions of the rotorcraft 1. This step 135 of determining a flight phase of the rotorcraft 1 may in particular be carried out using the second characteristics of the rotorcraft 1 and by means of the calculator 9. A flight phase is, for example, a take-off phase, a landing phase, a hovering flight phase, a level flight phase, a change of altitude phase and/or a maneuvering phase.

[0134] The first power distribution may thus be determined as a function of one or more second characteristics and/or the current flight phase of the rotorcraft 1. In this way, the first power distribution can be determined by taking into account the operating conditions of the rotorcraft 1 and the hybrid power plant 10. The first power distribution can thus help optimize the operation of each heat engine 11, 12 depending on these conditions, the electric motors 15, 17 then supplying the additional mechanical power necessary for the flight of the rotorcraft 1.

[0135] In this way, the first power distribution can be used to optimize the overall fuel consumption of each heat engine 11, 12 and/or to limit their ageing.

[0136] The first power distribution may also be predetermined, as long as the operating conditions of the heat engines 11, 12 and the electric motors 15, 17, as well as the source 19, permit. For example, the mechanical power requirement of the rotorcraft 1 is distributed according to a predetermined percentage between the heat engines 11, 12 and the electric motors 15, 17, as long as this predetermined percentage does not endanger the operation of the heat engines 11, 12 and of the electric motors 15, 17 and as long as the ability of the source 19 allows it. When this predetermined percentage can no longer be complied with, the calculator 9 modifies the first power distribution as a function of one or more first characteristics and the mechanical power requirement and also, possibly, as a function of one or more second characteristics.

[0137] For example, according to the predetermined percentage, the mechanical power requirement of the rotorcraft 1 is distributed so that the heat engines 11, 12 provide 80% of this mechanical power requirement and the electric motors 15, 17 provide 20% of this mechanical power requirement. Naturally, other percentages may be used for this power distribution.

[0138] In addition, the step 140 of determining a first power distribution may take into account the preservation of a backup electrical energy reserve for the electrical energy source 19. Thus, not all the electrical energy contained in the source 19 is taken into account when determining the first power distribution. Part of this electrical energy is preserved to be used in the event of failure of a heat engine 11, 12 such that the electric motor 15, 17 at least partially compensates for this failure.

[0139] The step 140 of determining a first power distribution may also take into account the flight plan of the rotorcraft 1 so that the total quantity of energy contained in the electrical energy source 19 is consumed on this flight plan and the source no longer contains electrical energy at the end of the flight. In particular, the backup reserve may then be used during the landing phase carried out at the end of the flight plan.

[0140] Furthermore, the method according to the disclosure may include different operating modes of the hybrid power plant 10 using the heat engines 11, 12 and the electric motors 15, 17 differently, the required operating mode being selected beforehand by a pilot of the rotorcraft, for example.

[0141] To this end, the method may comprise the following steps:

[0142] selecting 100 an operating mode to select an operating mode of the hybrid power plant 10 by means of a selection device 35; and

[0143] controlling 150 the two heat engines 11, 12 and the two electric motors 15, 17 by means of the two control units 13, 14 and the two control devices 16, 18 respectively, according to the operating mode selected from among the following operating modes according to the selection 100: [0144] the distributed operating mode 160 applying said first power distribution; [0145] a total operating mode 170 during which the power supplied by the hybrid power plant 10 is increased, each heat engine 11,12 supplying the maximum available power and each electric motor 15,17 supplying the maximum available power irrespective of the mechanical power requirement of the rotorcraft 1 and within the limits of the capability of the rotorcraft 1; and [0146] a “low-emission” operating mode 180 applying a second power distribution between the two heat engines 11, 12 and the two electric motors 15, 17, the second power distribution limiting polluting emissions from the hybrid power plant 10 for the environment outside the rotorcraft 1.

[0147] The selection device 35 may be a manual selector with several positions, such as a rotary knob provided with several positions, or else may be a screen and a touch panel, for example.

[0148] The total operating mode makes it possible to provide the maximum available power, for example in order to allow the rotorcraft 1 to take off with a large payload, perform a demanding maneuver, transport a heavy payload, increase the maximum flight altitude, etc.

[0149] The “low-emission” operating mode 180 allows a second power distribution in order to limit pollution in the environment outside the rotorcraft 1, which pollution may be noise pollution or else result from the exhaust gases from the heat engines 11, 12. This second power distribution may be predetermined. For example, the two electric motors 15, 17 provide the maximum possible power and energy depending on the quantity of electrical energy available in the source 19 and the two heat engines provide additional power depending on the mechanical power requirement of the rotorcraft. This “low-emission” operating mode 180 is limited in time by the quantity of electrical energy available in the source 19.

[0150] The second power distribution may also be calculated in real time by the calculator 9 as a function of one or more first characteristics, the power requirement and, possibly, one or more second characteristics. The second power distribution also takes account of the state of the electrical energy source 19, each electric motor 15, 17 and each heat engine 11, 12, and even the flight conditions of the rotorcraft 1.

[0151] In this case, the method according to the disclosure may comprise a step 145 of determining this second power distribution between each heat engine 11, 12 and each electric motor 15, 17 as a function of at least one first characteristic and of the mechanical power requirement of the rotorcraft 1, and possibly of at least one second characteristic.

[0152] Furthermore, the total operating mode 170 and/or the “low-emission” operating mode 180 may take into account the preservation of a backup electrical energy reserve for the electrical energy source 19.

[0153] Finally, irrespective of the selected operating mode, the first power distribution or the second power distribution may be determined so that at least one electric motor 15, 17 operates in an electrical energy generator mode in order to make it possible to recharge at least one electrical energy source 19 when possible, depending on the power requirement of the rotorcraft 1.

[0154] The charging power of the energy source 19 may also be determined as a function of the time required for a complete recharge, subject to its energy absorption capacity, depending, for example, on the temperature of the energy source 19, this temperature possibly increasing during charging.

[0155] Naturally, the present disclosure is subject to numerous variations as regards its implementation. Although several embodiments are described above, it should readily be understood that it is not conceivable to identify exhaustively all the possible embodiments.

[0156] For example, an example of a rotorcraft having a main lift rotor and an auxiliary rotor has been described. However, the disclosure can be applied to other types of rotorcraft, comprising, for example, a main lift rotor and one or more forward propellers. The disclosure can also be applied to a multirotor rotorcraft comprising several main rotors to ensure the lift, propulsion and maneuverability of the rotorcraft.

[0157] It is naturally possible to replace any of the means described with equivalent means without going beyond the ambit of the present disclosure.