PROVIDING ENERGY IN AN AIRCRAFT USING DROOP CONTROL

Abstract

An apparatus for providing energy in an aircraft, including a DC bus; at least one low-pressure electrical source and at least one high-pressure electrical source. The apparatus further includes a system for calculating a droop gain for each electrical source, based on at least one operating characteristic of the turbine engine; and for each electrical source, a model for controlling the electrical source in question, which module is designed to implement a droop setting based on the droop gain calculated for the electrical source in question.

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to an apparatus for providing energy in an aircraft, an aircraft comprising such an apparatus, and a corresponding method.

TECHNOLOGICAL BACKGROUND

It is known from the prior art to provide, in an aircraft, an energy providing apparatus of the type comprising:

• • a DC bus to which at least one electrical load is intended to be connected;
  • several electrical sources including:
    • at least one electrical source referred to as low-pressure electrical source designed to draw power from a low-pressure body of an aircraft turbomachine, in order to provide a current to the DC bus, and
    • at least one electrical source referred to as high-pressure electrical source designed to draw power from a high-pressure body of the turbomachine of the aircraft, in order to provide a current to the DC bus.

It may be desirable to provide a robust regulation of the electrical sources so as not to interfere significantly with the operation of the turbomachine.

For example, the document GB 2510121 A1 describes a frequency or voltage droop regulation with a master/slave system.

SUMMARY OF THE INVENTION

An apparatus for providing energy in an aircraft, of the abovementioned type, is therefore proposed, characterised in that it further comprises:

• • a system for calculating a droop gain for each low-pressure electrical source and each high-pressure electrical source, on the basis of at least one operating characteristic of the turbomachine; and
  • for each low-pressure electrical source and each high-pressure electrical source, a control module for controlling the electrical source under consideration, designed to implement a droop regulation on the basis of the droop gain calculated for the electrical source under consideration.

Thanks to the invention, it is possible to implement a decentralised regulation, i.e. independent from one electrical source to another. In this way, the regulation is robust to the loss of one of the sources. In addition, the fact that the droop gains are calculated on the basis of at least one operating characteristic of the turbomachine means that they can be defined in accordance with the desired operating point, so that the regulation does not substantially interfere with the operation of the turbomachine.

An energy providing apparatus according to the invention may further comprise one or more of the following optional characteristics, in any technically feasible combination.

Optionally, the at least one operating characteristic of the turbomachine comprises at least one of: a fuel inlet flow rate and/or an air inlet flow rate into a combustion chamber of the turbomachine, a rotational speed of the low-pressure body, a rotational speed of the high-pressure body, an air inlet temperature and/or a fuel inlet temperature and/or a temperature of exhaust gases leaving the combustion chamber.

Also optionally, the droop gain calculation system comprises:-a turbomachine controller designed to define a ratio between the power drawn from the high-pressure body by the high-pressure electrical source or sources and the power drawn from the low-pressure body by the low-pressure electrical source or sources, on the basis of the operating characteristic or characteristics of the turbomachine; and—for each electrical source, a module for calculating, on the basis of the ratio, the droop gain of the electrical source under consideration, so that the ratio is complied with.

Optionally also, the controller is designed to provide data referred to as power data representative of a maximum low pressure mechanical power that can be drawn from the low pressure body and a maximum high pressure mechanical power that can be drawn from the high pressure body, and each calculation module is designed to calculate the associated droop gain from the power data, so that the mechanical power drawn from the low pressure body remains less than or equal to the maximum low pressure mechanical power and the mechanical power drawn from the high pressure body remains less than or equal to the maximum high pressure mechanical power.

Also optionally, each calculation module is designed to calculate the associated droop gain so as to maximise a sum of the currents that can be respectively provided by the electrical sources, when the DC bus has a minimum bus voltage predefined by the droop regulation.

Also optionally, the apparatus comprises several high-pressure electrical sources and/or several low-pressure electrical sources, and the calculation module of each high-pressure or respectively low-pressure electrical source is designed to calculate the associated droop gain from a ratio between, on the one hand, the current provided by the high-pressure or respectively low-pressure source under consideration and, on the other hand, a sum of the currents respectively provided by all the high-pressure or respectively low-pressure electrical sources.

Also optionally, each calculation module is designed to calculate the droop gain of the high-pressure electrical source as the product of the ratio and a constant and the droop gain of the low-pressure electrical source as the product of the one's complement of the ratio and the constant.

Also optionally, each control module is designed to:

• • calculate a reference current from the associated droop gain;
  • calculate, from the power data, a maximum current that can be provided by the associated electrical source; and
  • limit the reference current to the maximum current.

An aircraft comprising an apparatus according to the invention is also proposed.

A method for providing energy in an aircraft is also proposed, characterised in that it comprises:

• • calculating, from at least one measurement of at least one operating characteristic of a turbomachine, a droop gain for:
    • each electrical source referred to as low-pressure electrical source designed to draw power from a low-pressure body of the turbomachine of the aircraft, in order to provide a current to a DC bus to which at least one electrical load is intended to be connected, and
    • each electrical source referred to as high-pressure electrical source designed to draw power from a high-pressure body of the turbomachine of the aircraft, in order to provide a current to the DC bus; and
  • for each low-pressure electrical source and each high-pressure electrical source, implementing a droop regulation on the basis of the droop gain calculated for the electrical source under consideration.

BRIEF DESCRIPTION OF THE FIGURES

The invention will be better understood with the aid of the following description, given only by way of example and made with reference to the attached drawings in which:

FIG. 1 is a simplified view of an apparatus according to the invention for providing energy in an aircraft,

FIG. 2 is a functional view of control modules for two electrical sources respectively coupled to a low-pressure body and a high-pressure body of a turbomachine, in order to provide currents to a DC bus, the control modules implementing a droop regulation,

FIG. 3 is a functional view of a droop gain calculation module for the control module of the electrical source coupled to the low-pressure body,

FIG. 4 is a functional view of a droop gain calculation module for the control module of the electrical source coupled to the high-pressure body,

FIG. 5 is a curve illustrating the relationship between the droop gains in order to achieve a desired distribution between mechanical power drawn from the low-pressure body and the mechanical power drawn from the high-pressure body, in a first operating case,

FIG. 6 illustrates the currents provided by the electrical sources as a function of a DC bus voltage, in the first operating case,

FIG. 7 is a curve illustrating the relationship between the droop gains in order to achieve a desired distribution between mechanical power drawn from the low-pressure body and the mechanical power drawn from the high-pressure body, in a second operating case,

FIG. 8 illustrates the currents provided by the electrical sources as a function of the DC bus voltage, in the second operating case,

FIG. 9 is a simplified view of another apparatus according to the invention for providing energy in an aircraft, with several electrical sources coupled to the high-pressure body,

FIG. 10 is a functional view of a droop gain calculation module for the control module of one of the electrical sources coupled to the high-pressure body,

FIG. 11 is a functional view of a droop gain calculation module for the control module of the other of the electrical sources coupled to the high-pressure body,

FIG. 12 is a functional view of an alternative of the control modules,

FIG. 13 is a functional view of an alternative droop gain calculation module for the control module of the electrical source coupled to the low-pressure body,

FIG. 14 is a functional view of an alternative droop gain calculation module for the control module of the electrical source coupled to the high-pressure body, and

FIG. 15 illustrates the currents provided by the electrical sources as a function of the DC bus voltage, in the alternative of FIGS. 12 to 14.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIG. 1, an example of an apparatus 100 for providing energy in an aircraft will now be described.

The apparatus 100 firstly comprises a turbomachine 102 comprising a low-pressure (BP) body 104 and a high-pressure (HP) body 106. The turbomachine 102 is, for example, an aircraft propulsion turbomachine.

The apparatus 100 also comprises a controller 108 for the turbomachine 102. This controller 108 is designed, for example, to regulate a fuel inlet flow rate and/or an air inlet flow rate into a combustion chamber of the turbomachine 102. To adjust the air inlet flow rate, the controller 108 controls, for example, the orientation of stator blades of a high pressure (HP) compressor 110 of the HP body 106. The controller 108 is designed, for example, to make these adjustments on the basis of at least one characteristic (measured and/or estimated, for example on the basis of other measurements) of operation of the turbomachine 102, for example one or more of: the fuel inlet flow rate and/or the air inlet flow rate, a rotational speed of the BP body 104, a rotational speed of the HP body 106, an air inlet temperature and/or a fuel inlet temperature and/or a temperature of exhaust gases leaving the combustion chamber.

The controller 108 is also designed to define a power draw ratio S between the BP body and the HP body. This ratio S is generally referred to as the “split” and expresses the proportion of mechanical power drawn from the HP 106 body (or alternatively from the BP 104 body) in relation to the mechanical power drawn from both the BP 104 and HP 106 bodies. The split S is expressed as a percentage, for example. The ratio S is defined on the basis of at least one characteristic (measured and/or estimated, for example on the basis of other measurements) of operation of the turbomachine 102, for example one or more of: the fuel inlet flow rate and/or the air inlet flow rate, a rotational speed of the BP body 104, a rotational speed of the HP body 106, an air inlet temperature and/or a fuel inlet temperature and/or a temperature of exhaust gases leaving the combustion chamber. The controller 108 is designed, for example, to define the split S on the basis of a look-up table associating values of the operating characteristic or characteristics of the turbomachine 102 with values of the split S.

Preferably, the controller 108 is also designed to calculate data referred to as power data representative of a maximum mechanical power that can be drawn from the BP body, noted P_{BPmax_meca}, and a maximum mechanical power that can be drawn from the HP body, noted P_{HPmax_meca}. This power data may comprise, for example, the maximum powers P_{BPmax_meca}, P_{HPmax_meca} themselves or the maximum torques C_BPmax, C_HPmax respectively provided by the BP body 104 and the HP body 106. The power data are for example calculated from at least one characteristic (measured and/or estimated, for example from other measurements) of operation of the turbomachine 102, for example one or more of: a torque of an output shaft of the turbomachine 102, the rotational speed of the BP body 104, the rotational speed of the HP body, the air inlet temperature and/or the fuel inlet temperature and/or the temperature of exhaust gases leaving the combustion chamber, the air inlet and/or fuel inlet flow rate, the air inlet and/or fuel inlet pressure, a torque provided by the BP body 104 and a torque provided by the HP body 106.

The apparatus 100 also comprises a direct current bus 112 to which at least one electrical load 114 is intended to be connected. Each load 114 corresponds, for example, to one or more items of equipment of the aircraft.

The apparatus 100 also comprises several electrical sources 116_BP, 116_HP, each designed to draw mechanical power from the turbomachine 102, in order to provide electrical power to the DC bus 112.

These electrical sources 116_BP, 116_HP comprise in particular one or more electrical sources, referred to as low pressure (BP), each designed to draw mechanical power from the BP body 104 of the turbomachine 102, in order to provide electrical power to the DC bus 112. In FIG. 1, the apparatus 100 comprises a single electrical source BP, designated by the reference 116_BP.

The electrical sources 116_BP, 116_HP also comprise one or more electrical sources, referred to as high pressure (HP), each designed to draw mechanical power from the HP body 106 of the turbomachine 102, in order to provide electrical power to the DC bus 112. In FIG. 1, the apparatus 100 comprises a single electrical source HP, designated by the reference 116_HP.

For example, each electrical source 116_BP, 116_HP comprises a generator followed by a rectifier.

The apparatus 100 also comprises, for each electrical source 116_BP, 116_HP, a control module 120_BP, 120_HP for the electrical source 116_BP, 116_HP under consideration, in particular its rectifier. Each control module 120_BP, 120_HP is designed to implement a droop regulation on the basis of a droop gain K_BP, K_HP associated with the electrical source 116₁, 116₂ under consideration.

The apparatus 100 also comprises, for each electrical source 116_BP, 116_HP, a module 122_BP, 122_HP for calculating, from the ratio S, the droop gain K_BP, K_HP for the electrical source 116_BP, 116_HP under consideration, so that the ratio S is complied with.

Generally speaking, the droop regulation consists of allowing the DC bus 112 to have a bus voltage U_DC that can vary slightly, between a nominal voltage U_DC* and a minimum voltage U_DCmin lower than the nominal voltage U_DC*, hence the term “droop”. Furthermore, in the droop regulation, each electrical source 116_BP, 116_HP is regulated to provide a current I_BP, I_HP proportional to the bus voltage drop ΔU_DC (equal to U_DC*−U_DC), the associated droop gain K_BP, K^HP constituting the proportionality ratio: I_BP=K_BP·ΔU_DC and I_HP=K_HP·ΔU_DC.

In this way, the regulation of the electrical sources 116_BP, 116_HP can be carried out independently of each other, but nevertheless remain coupled by the bus voltage U_DC so as together to reach a point of equilibrium in which the electrical power contribution provided to the DC bus 112 by each electrical source 116_BP, 116_HP is defined by the droop gains K_BP, K_HP. By adjusting the latter, it is therefore possible to set the relative contributions of the electrical sources 116_BP, 116_HP.

For example, the provided current I_BP, I_HP is regulated to follow a reference current I_BP*, I_HP* given by I_BP*=K_BP·ΔU_DC and I_HP*=K_HP·ΔU_DC. This implementation example will now be described with reference to FIG. 2.

In this example, each control module 120_BP, 120_HP comprises a block 202_BP, 202_HPfor calculating the reference current I_BP*, I_HP* from the bus voltage U_DC, the nominal bus voltage U_DC* and the droop gain K_BP, K_HP.

Each control module 122_BP, 122_HP further comprises a block 204_BP, 204_HP for comparing the current provided I_BP, I_HP with the reference current I_BP*, I_HP* to provide a current error. Each control module 122_BP, 122_HP further comprises a regulation block designed to provide commands to the electrical source 116_BP, 116_HP from the current error. These commands tend to make the current provided I_BP, I_HP equal to the reference current I_BP*, I_HP*, in other words, they tend to cancel the current error. The commands are, for example, pulse-width modulation commands PWM_BP or PWM_HP.

With reference to FIG. 3 and FIG. 4, an example of the implementation of the modules 122_BP, 122_HP for calculating droop gains K_BP, K_HP will now be described.

Each module 122_BP, 122_HP comprises, for example, a block 302 for calculating a maximum electrical power P_BPmax, P_HPmax that can be provided by the associated electrical source 116_BP, 116_HP. Preferably, this maximum electrical power P_BPmax, P_HPmax takes account of the maximum mechanical power P_{BPmax_meca}, P_{HPmax_meca} that can be drawn, which is, for example, provided by the controller 108 or calculated from the maximum torque provided by the controller 108 and the speed of rotation of the body BP 104, respectively of the body HP 106, and/or of a nominal power P_{BPmax_elec}, P_{HPmax_elec} of the electrical source 116_BP, 116_HP under consideration. For example, the maximum electrical power P_BPmax, P_HPmax is the minimum between the maximum mechanical power P_{BPmax_meca}, P_{HPmax_meca} that can be drawn and the nominal power P_{BPmax_elec}, P_{HPmax_elec} of the electrical source 116_BP, 116_HP under consideration.

Generally, the nominal powers P_{BPmax_elec}, P_{HPmax_elec} of the electrical sources 116_BP, 116_HP depend on their design and are fixed. On the other hand, the maximum mechanical powers P_{BPmax_meca}, P_{HPmax_meca} that can be drawn generally depend on the operating point and the state of the turbomachine 102 and therefore change over time. This means that the maximum electrical powers P_BPmax and P_HPmax can change over time.

Each module 122_BP, 122_HP also comprises a block 304 for calculating a maximum droop gain K_BPmax, K_HPmax, allowing the associated electrical source 116_BP, 116_HP to provide the maximum power P_BPmax, P_HPmax, in particular when the bus voltage U_DC is the minimum bus voltage U_DCmin.

In general, the same ratio S can be obtained by several droop gains K_BP, K_HP. Preferably, the modules 122_BP, 122_HP for calculating the droop gains K_BP, K_HP are designed to calculate the latter to maximise the sum of the currents I_BP, I_HP that can be provided by the electrical sources 116_BP, 116_HP.

The maximum current I_BPmax, I_HPmax that can be provided by each electrical source 116_BP, 116_HP is that provided when the bus voltage U_DC is equal to the minimum bus voltage U_DCmin, i.e. for a maximum voltage drop ΔU_DCmax=U_DC*−U_DCmin. The maximum currents I_BPmax, I_HPmax that can be provided are then given by: I_BPmax=K_BP·ΔU_DCmax and I_HPmax=K_HP·ΔU_DCmax. Thus, taking into account the calculated maximum powers P_BPmax, P_HPmax, the maximum droop gains K_BPmax, K_BPmax are given by: K_BPmax=P_BPmax/(ΔU_DCmax·U_DCmin) et K_HPmax=P_HPmax/(ΔU_DCmax·U_DCmin).

Furthermore, the ratio S is given by S=K_HP/(K_HP+K_BP). Thus, for a given ratio S, the droop gains are related to each other by K_BP=(1−S)/S·K_HP.

Referring to FIGS. 5 to 7, it is easy to see that the sum of the currents supplied I_BP, I_HP is at its maximum when one of the droop gains H_HP, K_HP is at its maximum. To comply with the maximum powers P_BPmax, P_HPmax, it is also necessary to ensure that the other droop gain K_BP, K_HP is well below (or equal to) its maximum. In the example shown in FIGS. 5 and 6, it is the droop gain K_HP that can reach its maximum K_HPmax, with the other droop gain K_BP below its maximum K_BPmax. The droop gain K_BP is then K_BP=(1−S)/S·K_HPmax. In the example shown in FIGS. 7 and 8, it is the droop gain K_BP that can reach its maximum K_BPmax, with the other droop gain K_HP below its maximum K_HPmax. The droop gain K_HP is then K_HP=S/(1−S)·K_BPmax.

Thus, each of the modules 122_BP, 122_HP also comprises a block 306 designed to determine whether the droop gain K_BP, K_HP to be provided should be taken at its maximum or not. For example, the block 306 of each module 122_BP, 122_HP is designed to determine whether the droop gain K_BP, K_HP to be provided is less than its maximum K_BPmax, K_HPmax, assuming the other droop gain is at its maximum. For example, the block 306 of the module 122_BP checks whether (1−S)/S·K_HPmax is less than K_BPmax, while the block 306 of the module 122_HP checks whether S/(1−S)·K_BPmax is less than K_HPmax. Alternatively, other equivalent inequalities could be used.

If the block 306 determines that the droop gain K_BP, K_HP to be provided should be taken at its maximum, each module 122_BP, 122_HP is designed to provide the droop gain K_BP, K_HP at its maximum K_BPmax, K_HPmax.

Alternatively, each module 122_BP, 122_HP is designed to calculate the droop gain K_BP, K_HP to be provided from the ratio S and the other droop gain K_BP, K_HP, taken at its maximum K_BPmax, K_HPmax.

With reference to FIG. 9, another example of an apparatus 900 providing energy in an aircraft will now be described.

The apparatus 900 is similar to the apparatus 100 in FIG. 1, except that it comprises several high-pressure electrical sources instead of just one, two in the example described, designated by the references 116_HP1, 116_HP2. Overall, these two high-pressure electrical sources 116_HP1, 116_HP2 behave like the single high-pressure electrical source 116_HP of FIG. 1.

The apparatus 900 thus comprises, for each high-pressure electrical source 116_HP1, 116_HP2, a control module 120_HP1, 120_HP2 and a module 122_HP1, 122_HP2 for calculating the respective droop gain K_HP1, K_HP2.

In this case, with reference to FIG. 10 and FIG. 11, each module 122_HP1, 122_HP2 uses, for example, a respective secondary ratio s1, s2. Each secondary ratio s1, s2 represents the portion of the current I_HP1, I_HP2 provided by the high-pressure electrical source 122_HP1, 122_HP2 under consideration relative to the sum of the currents I_HP1, I_HP2 provided by the assembly of the high-pressure electrical sources 116_HP1, 116_HP2. So the sum of the secondary ratios s1, s2 is one. These secondary ratios s1, s2 are fixed, for example.

For example, each module 122_HP1, 122_HP2 is identical to the module 122_HP, except that the secondary ratio s1, s2 is taken into account when calculating the droop gain K_HP1, K_HP2 to be provided.

In the example shown, the blocks 306 are designed to test equality using a total high pressure gain K_HP=K_HP1+K_HP2, in the same way as in FIG. 4. Alternatively, other equivalent inequalities could be used, for example s1·S/(1−S)·K_BPmax<K_HP1max=s1·K_HPmax for the block 306 of the module 122_HP1 and s2·S/(1−S)·K_BPmax<K_HP1max=s2·K_HPmax for the block 306 of the module 122_HP2.

With reference to FIG. 12, a further example of the implementation of the control modules 120_BP, 120_HP will now be described.

The control modules 120_BP, 120_HP are identical to those in FIG. 2, except that they each also comprise a module 1202_BP, 1202_HP for calculating a maximum current I_BPmax, I_HPmax and a module 1204_BP, 1204_HP for limiting the reference current I_BP*, I_HP* to this maximum current I_BPmax, I_HPmax. Thus, as long as each reference current I_BP*, I_HP* is less than its respective maximum current I_BPmax, I_HPmax, the electrical sources 116_BP, 116_HP are controlled according to the droop gains K_BP, K_HP, so that the split S is respected. On the other hand, if one of the reference currents I_BP*, I_HP* becomes greater than its respective maximum current I_BPmax, I_HPmax, this reference current I_BP*, I_HP* is limited, and therefore also the current I_BP, I_HP provided to the DC bus 112. The other reference current IBP*, I_HP* can then continue to increase (until it reaches its associated maximum current I_BPmax, I_HPmax). This allows more current to be delivered to the DC bus 112, to the detriment of the split S, which is no longer respected.

With reference to FIG. 13 and FIG. 14, another example of implementation of the modules 122_BP, 122_HP for calculating the droop gains K_BP, K_HP of FIG. 1, which can in particular be used in combination with the control modules 120_BP, 120_HP of FIG. 12, will now be described.

The modules 122_BP, 122_HP are identical to those of FIG. 3 and FIG. 4, except that they comprise, instead of the block 306, a block 1302 for calculating the droop gain K_BP, K_HP from a constant K_tmax deduced from the maximum powers P_BPmax, P_HPmax and the split S.

More precisely, the droop gain K_HP is given by: K_HP=S·K_tmax, while the droop gain K_HP is given by: K_BP=(1−S)·K_tmax. (1−S) is therefore the one's complement of the split S.

Preferably, the constant K_tmax is equal to the sum of the maximum droop gains K_BPmax, K_HPmax:K_tmax=K_BPmax+K_HPmax.

The bus voltage U_DC as a function of the currents I_BP, I_HP provided to the DC bus 112 is shown in FIG. 15, in the case of a 50% split. As can be seen, the I_BP* reference current has reached saturation.

In conclusion, it should be noted that the invention is not limited to the embodiments described above. In fact, it will appear to the person skilled in the art that various modifications can be made to the above-described embodiments, in the light of the teaching just disclosed.

In the foregoing detailed presentation of the invention, the terms used should not be interpreted as limiting the invention to the embodiments exposed in the present description, but should be interpreted to include all equivalents the anticipation of which is within the reach of the person skiled in the art by applying his general knowledge to the implementation of the teaching just disclosed.

Claims

1. An apparatus for providing energy in an aircraft, comprising: a DC bus to which at least one electrical load is intended to be connected;several electrical sources including: at least one electrical source referred to as low-pressure electrical source designed to draw power from a low-pressure of a turbomachine of the aircraft, in order to provide a current to the DC bus, andat least one electrical source referred to as high-pressure electrical source designed to draw power from a high-pressure body of the turbomachine of the aircraft, in order to provide a current to the DC bus;

2. The apparatus according to claim 1, wherein the at least one operating characteristic of the turbomachine comprises at least one of: a fuel inlet flow rate and/or an air inlet flow rate into a combustion chamber of the turbomachine, a rotational speed of the low-pressure body, a rotational speed of the high-pressure body, an air inlet temperature and/or fuel inlet temperature and/or temperature of exhaust gases leaving the combustion chamber.

3. The apparatus according to claim 1, wherein the system for calculating droop gains comprises: a controller of the turbomachine designed to define a ratio(S) between the power drawn from the high-pressure body by the high-pressure electrical source or sources and the power drawn from the low-pressure body by the low-pressure electrical source or sources, on the basis of the operating characteristic or characteristics of the turbomachine; andfor each electrical source, a module for calculating, from the ratio, the droop gain of the electrical source under consideration, so that the ratio is complied with.

4. The apparatus according to claim 3, wherein the controller is designed to provide data referred to as power data representative of a maximum low-pressure mechanical power that can be drawn from the low-pressure body and a maximum high-pressure mechanical power that can be drawn from the high-pressure body, and wherein each calculation module is designed to calculate the associated droop gain from the power data, so that the mechanical power drawn from the low-pressure body remains less than or equal to the maximum low-pressure mechanical power and the mechanical power drawn from the high-pressure body remains less than or equal to the maximum high-pressure mechanical power.

5. The apparatus according to claim 4, wherein each calculation module is designed to calculate the associated droop gain as to maximise a sum of the currents which can respectively be provided by the electrical sources when the DC bus has a minimum bus voltage predefined by the droop regulation.

6. The apparatus according to claim 1, comprising a plurality of high-pressure electrical sources and/or a plurality of low-pressure electrical sources, and wherein the calculation module of each high-pressure electrical source, respectively low-pressure electrical source, is designed to calculate the associated droop gain on the basis of a ratio between, on the one hand, the current provided by the high-pressure source, respectively low-pressure source, under consideration and, on the other hand, a sum of the currents respectively provided by all the high-pressure electrical sources, respectively low-pressure electrical sources.

7. The apparatus according to claim 4, wherein each calculation module is designed to calculate the droop gain of the high-pressure electrical source as the product of the ratio and a constant and the droop gain of the low-pressure electrical source as the product of the one's complement of the ratio and the constant.

8. The apparatus according to claim 1, wherein each control module is designed to: calculate a reference current) from the associated droop gain;calculate, from the power data, a maximum current that can be provided by the associated electrical source; andlimit the reference current to the maximum current.

9. An aircraft comprising an apparatus according to claim 1.

10. A method for providing energy in an aircraft, wherein said method comprises: calculating, from at least one measurement of at least one operating characteristic of a turbomachine, a droop gain for: each electrical source referred to as low-pressure electrical source designed to draw power from a low-pressure body of the turbomachine of the aircraft, in order to provide a current to a DC bus to which at least one electrical load is intended to be connected, andeach electrical source referred to as high-pressure electrical source designed to draw power from a high-pressure body of the turbomachine of the aircraft, in order to provide a current to the DC bus; andfor each low-pressure electrical source and each high-pressure electrical source, a droop regulation is implemented on the basis of the droop gain calculated for the electrical source under consideration.