Method for regulating the voltage of a busbar in an electrical system, and the corresponding system and aircraft.

Abstract

A method for regulating the voltage of at least one busbar (12) of an electrical system (10), the busbar being supplied by at least one source, the source being a fuel cell system (14) comprising at least one fuel cell (15) and a compressor (16) associated with the fuel cell, the busbar also supplying loads, including at least one dissipative load, the method comprising the step of, if the compressor is switched to doped mode, controlling a modification of the power supply to at least one of the loads, starting first with the dissipative load(s). ABRIDGED FIGURE: Fig. 1

Description

Title of the invention: Method for voltage regulation of a bus bar of an electrical system, corresponding system and aircraft

[0001] The present invention relates to a method for voltage regulation of a bus bar of an electrical system of an aircraft.

[0002] The invention also relates to an electrical system implementing such a method and to an aircraft equipped with such a system.

[0003] BACKGROUND OF THE INVENTION

[0004] Climate change is a major concern for many legislative and regulatory bodies worldwide. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new types of aircraft and those currently in operation, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been mobilizing for several years now to contribute to the fight against climate change.

[0005] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into account the factors impacting all phases of design and development in order to obtain less energy-intensive, more environmentally friendly aeronautical components and products whose integration and use in civil aviation have moderate environmental impacts, with the aim of improving the energy efficiency of aircraft.

[0006] Consequently, the Applicant is constantly working to reduce its climate impact by using methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0007] This sustained research and development work focuses on new generations of aircraft engines, the lightening of aircraft, in particular through the materials used and lighter on-board equipment, the development of the use of electrical technologies to provide propulsion, and, as essential complements to technological progress, aviation biofuels.

[0008] An aircraft turbomachine conventionally comprises, from upstream to downstream (according to a direction of gas flow in the turbomachine): a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, A low-pressure turbine and a gas exhaust nozzle. The low-pressure compressor, high-pressure compressor, high-pressure turbine, and low-pressure turbine each have rotors rotating within housings connected to each other and to the combustion chamber and nozzle to form a tubular assembly that defines an annular space for the primary gas flow. The rotor of the high-pressure turbine is rotationally linked to the rotor of the high-pressure compressor to drive the latter, and the rotor of the low-pressure turbine is rotationally linked to the rotor of the low-pressure compressor to drive the latter. The assembly comprising the high-pressure turbine and the high-pressure compressor is called a high-pressure system, and the assembly comprising the low-pressure turbine and the low-pressure compressor is called a low-pressure system.

[0009] With the increasing integration of electrical elements within aircraft, it has been proposed to associate with turbomachines at least one electrical interface between the turbomachine and one or more electrical systems of the aircraft.

[0010] The electrical interface is thus used to perform one or more functions such as assisting the turbomachine in starting or taking part of the power generated by the turbomachine to power one or more devices of the aircraft (the majority of the power produced by the turbomachine being of course used for the propulsion of the aircraft).

[0011] Typically, these devices are connected to a busbar which is itself powered by one or more electrical power sources, including the electrical interface. Additional sources may include, for example, a storage device, a battery, or even a fuel cell.

[0012] In order for the busbar to function correctly, its voltage must be regulated so that it remains within a predefined operating range.

[0013] However, during a particularly large electrical power demand from the device(s), it proves difficult to maintain the voltage of the bus bar within the said predefined operating range.

[0014] SUBJECT OF THE INVENTION

[0015] The invention aims to overcome at least partially the aforementioned drawback. Summary of the invention

[0016] To this end, the invention proposes a method for regulating the voltage of at least one busbar of an electrical system, the busbar being supplied by at least one source, the source being a fuel cell system comprising at least one fuel cell and a compressor associated with the fuel cell, the busbar also supplying loads, including at least one dissipative load, the method comprising the steps of: - Given a characteristic value of the electrical current generated by the fuel cell system and a setpoint of a characteristic value of the electrical current to be generated by the fuel cell system resulting in an increase in the power to be delivered by the fuel cell system, estimate whether the fuel cell can reach the setpoint in a time interval that is equal to or less than a predetermined time interval. - If the fuel cell cannot reach the setpoint within a time interval equal to or less than a predetermined time interval, switch the compressor from nominal mode to boosted mode if it was not already in boosted mode. - If the compressor is switched to doped mode, order a change in the power supply to at least one of the loads, starting first with said at least one dissipative load.

[0017] Thanks to the invention, we study whether the battery can cope alone or not with the demand for modification of the electrical power to be delivered.

[0018] The invention proposes to temporarily control the power supply to one or more loads in order to charge or discharge the electrical system, and in particular the busbar. This makes it possible to maintain the busbar voltage more stably within its predetermined operating range.

[0019] The invention makes it possible, for example, to reduce the time required for the battery system to reach the setpoint imposed on it, by taking from the busbar an additional delta of electrical power in order to inject it into the compressor.

[0020] Prioritizing the loads affected by the change in power supply allows for intelligent regulation of the voltage across the busbar. In particular, this prevents a sudden load shedding of all loads connected to the busbar or a collapse in the electrical system's supply voltage.

[0021] Preferably, the characteristic quantity of an electric intensity generated by the battery system is either the electric power delivered by the battery system or directly the electric intensity generated by the battery system.

[0022] Preferably, the setpoint for a characteristic quantity of an electrical intensity to be generated by the battery system is either a setpoint for electrical power to be delivered by the battery system or a setpoint for electrical intensity to be delivered by the battery system.

[0023] Preferably, the modification of the power supply of at least one of the loads consists of a temporary shutdown of the power supply to said load (total load shedding) or a reduction or increase in the power supply to said load (partial load shedding).

[0024] The loads are therefore used temporarily as actuators for regulating the voltage of the busbar.

[0025] The invention is thus the result of technological research aimed at significantly improving aircraft performance and, in this sense, contributes to reducing the environmental impact of aircraft.

[0026] Optionally, the loads supplied by the bar include at least one regenerative load, and in which a change in the power supply of said at least one dissipative load is commanded first before a change in the power supply of said at least one regenerative load is commanded.

[0027] Optionally, the dissipative loads are classified into at least two different priority categories, the dissipative loads belonging to the first category being those whose power supply is the first to be modified.

[0028] Optionally, the busbar is a main busbar, the dissipative loads belonging to the first category are grouped into at least one group which is connected to a secondary busbar itself connected to the main busbar (via an electronic power converter.

[0029] Optionally, the method includes the step of lowering a voltage across the terminals of the secondary busbar to modify the power supply provided to the group by the main busbar.

[0030] Optionally, the process also includes the steps of: - Given a characteristic value of the electrical current generated by the fuel cell system and a setpoint of a characteristic value of the electrical current to be generated by the fuel cell system resulting in a decrease in the power to be delivered by the fuel cell system, estimate whether the fuel cell can reach the setpoint in a time interval that is equal to or less than a predetermined time interval. - If the fuel cell cannot reach the setpoint within a time interval that is equal to or less than a predetermined time interval, command a change in the power supply to at least one of the loads, starting first with the dissipative load(s).

[0031] Optionally, if the time interval is greater than the predetermined time interval, at least one other source is used to supply the busbar.

[0032] Optionally, in which is implemented through at least one energy storage unit serving as an additional source to the bus bar.

[0033] The invention also relates to an electrical system implementing the process as described above.

[0034] The invention also relates to an aircraft comprising at least the electrical system as mentioned above.

[0035] Other features and advantages of the invention will become apparent from the following description of a particular, non-limiting embodiment of the invention. Brief description of the drawings

[0036] The invention will be better understood in the light of the following description, which is illustrative and not limiting, and should be read in conjunction with the accompanying drawings, among which:

[0037] [Fig-1] [Fig.1] is a schematic view of a system according to one embodiment particular of the invention allowing the implementation of a voltage regulation method for a busbar of an aircraft electrical system;

[0038] [Fig.2a] [Fig.2a] is a diagram illustrating the exchanges between the stack system and a general controller of the system represented in [Fig.1] according to a first configuration;

[0039] [Fig.2b] [Fig.2b] is a diagram illustrating mode switching of operation of a compressor of the pile system shown in [Fig.2a];

[0040] [Fig.3a] [Fig.3a] is a diagram illustrating the exchanges between the stack system and a general controller of the system represented in [Fig.1] according to a second configuration;

[0041] [Fig.3b] [Fig.3b] is a flowchart illustrating different stages of preparation of the compressor for a future increase in electrical power to be generated by the battery system shown in [Fig.3a]. DETAILED DESCRIPTION OF THE INVENTION

[0042] With reference to [Fig.1], an electrical system 10 according to a particular embodiment of the invention is described herein in application to a double-flow turbomachine 1 of an aircraft A.

[0043] The turbomachine 1 comprises, from upstream to downstream according to a direction of gas flow in said turbomachine 1: a blower 2, a low-pressure compressor 3, a high-pressure compressor 4, a combustion chamber 5, a high-pressure turbine 6 and a low-pressure turbine 7. The low-pressure compressor 3, the high-pressure compressor 4, the high-pressure turbine 6 and the low-pressure turbine 7 each comprise a rotating rotor in a casing.

[0044] The rotor of the high-pressure turbine 6 and the rotor of the low-pressure turbine 7 are respectively fixed in rotation to the rotor of the high-pressure compressor 4 and to the rotor of the low-pressure compressor 3, so that the rotor of said high-pressure turbine 6 and the rotor of said low-pressure turbine 7 respectively drive the rotor of said high-pressure compressor 4 and the rotor of said low-pressure compressor 3 in rotation around a longitudinal axis X of the turbomachine 1 under the effect of the thrust of the gases coming from the combustion chamber 5.

[0045] The mass of air drawn in by the blower 2 is divided into two flows: a primary flow Fl which flows in an annular primary flow channel Cl, and a secondary flow F2 which is concentric with the primary flow Fl and which flows in an annular secondary flow channel C2.

[0046] The assembly comprising the low-pressure turbine 7 and the low-pressure compressor 3 is also known as the "high-pressure system" and the assembly comprising the high-pressure turbine 6 and the high-pressure compressor 4 is also known as the "low-pressure system".

[0047] The general arrangement of the turbomachine 1 described is conventional and will not be further detailed here.

[0048] The electrical system 10 includes at least one general controller 11 associated with the turbomachine 1.

[0049] The management system 10 also includes a busbar 12 and, for example, a DC busbar 12. The busbar 12 here includes its own controller 13, which is also in communication with the main controller 11.

[0050] The omnibus bar 12 is supplied by at least one first source.

[0051] The first source is a fuel cell system 14 comprising at least one fuel cell 15 and at least one compressor 16 associated with the fuel cell 15. The fuel cell system 14 also includes a fuel cell system controller 14, hereinafter referred to as the "fuel cell controller 17". The fuel cell controller 17 is configured to exchange one or more data points with the general controller 11.

[0052] As is known per se, the compressor 16 can operate in at least two modes, a nominal mode and a boosted mode. When in its boosted mode (which is a temporary mode, the compressor 16 normally operating in nominal mode), the compressor 16 increases the air flow rate it compresses, thus enabling it to supply more power to the fuel cell 15. The fuel cell controller 17 consequently controls the hydrogen flow rate transmitted to the fuel cell 15, allowing it to temporarily increase the electrical power it delivers to the busbar 12. In its boosted mode, the compressor 16 exhibits a compression power that is, for example, between 125 and 150% of the compression power of the compressor 16 when the compressor 16 is in its nominal mode. Furthermore, with reference to [Fig.2a], the general controller 11 transmits to the battery controller 17 a command of an electrical power to be delivered to the omnibus bar 12.The battery controller 17 can transmit to the general controller 11 one or more data indicating for example what maximum electrical power the battery system 17 can deliver, whether the compressor 16 is in nominal mode, or in boosted mode ... .

[0053] The stack controller 17 also receives from the stack system 14 one or more data such as, for example, one or more data from the following list: stack operating status fuel cell 15, fuel cell operating point 15, pressure in fuel cell 15, temperature in fuel cell 15, voltage across fuel cell 15 terminals ...

[0054] The battery system 14 is connected to the busbar 12 either directly or indirectly through at least one additional electrical and / or electronic component such as, for example, a power electronic converter 18. Said power electronic converter 18 is, for example, a DC / DC converter.

[0055] Said electronic power converter 18 here includes its own controller 19 which is in communication with the battery controller 17 and / or the general controller 11.

[0056] Preferably, the busbar 12 is supplied by at least one second source in the form of a storage unit 20.

[0057] The storage unit 20 is, for example, a battery.

[0058] The storage unit 20 is connected to the busbar 12 either directly, either indirectly through at least one electrical and / or electronic component such as for example an electronic power converter 21. Said electronic power converter 21 is for example a direct current / direct current converter.

[0059] Said electronic power converter 21 here includes its own controller 22 which is in communication with the general controller 11.

[0060] Said electronic power converter 21 is preferably reversible so that the storage unit 20 can be recharged via the busbar 12.

[0061] The storage unit 20 is connected to the busbar 12 by a channel (such as a DC channel) connected in parallel with the channel connecting the battery system 14 to the busbar 12.

[0062] Optionally, the busbar 12 is supplied by at least one third source. The third source is, for example, an electric machine 23 and, for example, a permanent magnet synchronous machine.

[0063] Said electric machine 23 is for example connected to the low pressure system of the turbomachine 1 and / or high pressure system of the turbomachine 1. For example the electric machine 23 is connected to the turbomachine 1 to take, at the level of the low pressure system and / or the high pressure system, part of a power generated by the turbomachine 1.

[0064] The electric machine 23 is connected to the busbar 12 either directly or indirectly via at least one electrical and / or electronic component such as, for example, an electronic power converter 24. Said Power electronic converter 24 is for example an alternating current / direct current converter.

[0065] Said electronic power converter 24 is preferably reversible.

[0066] Said electronic power converter 24 here includes its own controller 25 who is in communication with the Comptroller General 11.

[0067] The electric machine 23 is connected to the busbar 12 by a channel (such as a DC channel) connected in parallel with the channel connecting the battery system 14 to the busbar 12 and / or the channel connecting the storage unit 20 to the busbar 12.

[0068] Optionally, the busbar 12 is powered by at least one fourth source (not shown here). This fourth source is an external power supply. Preferably, this connection is made in parallel with one or more channels connecting one or more other sources to the busbar 12.

[0069] Furthermore, the omnibus bar 12 allows one or more devices of the aircraft 1 to be supplied, hereafter referred to as "loads".

[0070] In practice, the loads connected to the busbar 12 are classified into several categories. This classification is, for example, manually entered into the general controller 11, which records it.

[0071] The charges are preferably divided into at least two categories: dissipative charges and regenerative charges.

[0072] Regenerative loads have the capacity to temporarily supply electrical power to the busbar 12, thereby temporarily acting as a power source. These regenerative loads are of the fan, pump (fuel pump, oil pump), etc. type. Typically, these regenerative loads are rotating loads. Indeed, they comprise a rotating moving element that can return electrical power to the busbar 12 by converting the mechanical motion of the moving element into electrical energy.

[0073] A regenerative charge can be: - connected directly to the omnibus bar 12 (optionally via an additional contactor); - indirectly connected to busbar 12 via an electrical and / or electronic component such as an electronic power converter, a contactor that can potentially provide the link between busbar 12 and the electrical and / or electronic component; - indirectly connected to the busbar 12 via several electrical and / or electronic components such as, for example, a power converter to which a busbar is connected additional and to which the load is itself connected, a contactor potentially able to provide the link between the busbar 12 and one of the electrical and / or electronic components.

[0074] By way of non-limitation, in the present case, only one regenerative load 26 is connected to the busbar 12.

[0075] In the present case, and without limitation, the regenerative load 26 is connected to the bus bar 12 via an electronic power converter 27. Said electronic power converter 27 is, for example, a DC / DC converter.

[0076] Said electronic power converter 27 here includes its own controller 28 which is in communication with the general controller 11.

[0077] Dissipative charges, unlike regenerative charges, do not have the capacity to return energy to the bus bar 12. They simply absorb electrical energy and convert it, in case of surplus, into heat or other forms of energy.

[0078] Several types of dissipative charges can be distinguished.

[0079] Dissipative loads of type 1 (for example a step-down converter) are loads connected indirectly to the busbar 12 via several electrical and / or electronic components (and optionally via an additional contactor) such as, for example, a power converter to which a secondary busbar is connected and to which the load is itself connected.

[0080] By way of exception, in the present case, the dissipative loads of type 1 are connected to an additional busbar 29, which is itself connected to the busbar 12 via a power electronic converter 30. Said power electronic converter 30 is, for example, a DC / DC converter. Said power electronic converter 30 is, for example, configured to allow the supply of lower power loads than those connected, for example, directly to the busbar 12. Said power electronic converter 30 is, for example, configured to allow the conversion of a voltage of 800 Volts (DC) to a voltage of 540 Volts (DC) or 270 Volts (DC).

[0081] Said electronic power converter 30 here includes its own controller 31 which is in communication with the general controller 11.

[0082] For example, two dissipative loads 32, 33 of type 1 are connected to the additional busbar 29.

[0083] Dissipative loads of type 2 are loads connected directly to the busbar 12 (optionally via a contactor).

[0084] By way of non-limitation, in the present case only one dissipative load 34 of type 2 is connected to the busbar 12.

[0085] Type 3 dissipative loads are loads indirectly connected to the busbar 12 via a single electrical and / or electronic component, such as a power electronic converter (and optionally via an additional contactor). Examples of type 3 dissipative loads include de-icing devices (for an aircraft nacelle, an aircraft drum / spinner, etc.) or anti-icing devices for aircraft wings.

[0086] By way of non-limitation, in the present case only one dissipative load 35 of type 3 is connected to the bar.

[0087] In the present case, and without limitation, the dissipative load 35 is connected to the bar via an electronic power converter 36. Said electronic power converter 36 is, for example, a DC / DC converter.

[0088] The electronic power converter 36 here includes its own controller 37 which is in communication with the general controller 11.

[0089] Preferably, the dissipative charges are themselves classified into at least two different priority categories.

[0090] We therefore have here three categories of charges: dissipative charges of priority 1, dissipative charges of priority 2 and regenerative charges.

[0091] Priority 1 dissipative loads preferably include type 1 loads (i.e., here, loads 32 and 33). Priority 2 dissipative loads preferably include type 2 loads and type 3 loads (i.e., here, loads 34 and 35).

[0092] In service, the omnibus bus 12 allows the various loads to be supplied thanks to its supply from the different sources.

[0093] For the electrical system 10, and in particular the busbar 12, to operate optimally (especially in terms of stability), the electrical power generated by the sources must be substantially equal to the electrical power consumed by the loads at all times. Indeed, if the electrical power generated is less than the electrical power consumed by the loads, the voltage across the busbar 12 decreases, and if the electrical power generated is greater than the electrical power consumed by the loads, the voltage across the busbar 12 increases. However, the voltage of the busbar 12 must remain within a predefined operating range.

[0094] Therefore, the electrical system 10 is configured to implement a voltage regulation method for the busbar 12 in order to maintain said voltage within the predefined operating range and to limit fluctuations in said voltage.

[0095] For this purpose, the electrical system 10 preferably relies on the battery system 14 to regulate the voltage of the busbar 12. In particular, the electrical system 10 will take advantage of the fact that the battery system 14 can occasionally deliver increased electrical power thanks to the compressor 16 and its boosted mode.

[0096] Thus, in a first step, the general controller 11 estimates the electrical power to be delivered to the loads by the busbar 12 and the electrical power supplied by the different sources to the busbar 12. In the event of an increase in the electrical power consumed by the loads, the general controller 11 preferably transmits to the battery system 14 a setpoint of an electrical power to be reached to compensate for this demand from the loads.

[0097] In a second step, as symbolized by [Fig.2b], the fuel cell controller 17, knowing the electrical power already generated by the fuel cell 15 and receiving the electrical power setpoint from the general controller 11, estimates whether the fuel cell 15 alone can reach the setpoint in a time interval that is equal to or less than a predetermined time interval, for example between a few milliseconds and ten milliseconds.

[0098] In a third step, if the fuel cell controller 17 determines that the fuel cell 15 cannot reach the power setpoint on its own within the predetermined time interval, the fuel cell controller 17 switches the compressor 16 from its nominal mode to its boosted mode. The fuel cell controller 17 informs the main controller 11 of this switchover. The compressor 16 increases its compression power through its power supply via the electrical system 10.

[0099] Simultaneously, the fuel cell controller 17 transmits to the compressor 16 a setpoint to increase at least one characteristic parameter of the airflow transmitted by the compressor 16 to the fuel cell 15 (setpoint for efficiency, mass flow rate of air at the inlet of the compressor 16, setpoint for mass flow rate of air at the outlet of the compressor 16, etc.). This setpoint is estimated from at least one piece of information related to the state of the fuel cell system 14 (such as the operating point of the fuel cell 15) and the electrical power setpoint transmitted by the general controller 11. This setpoint can change over time and, for example, decrease as the fuel cell 15 reaches its electrical power setpoint transmitted by the general controller 11.

[0100] During the fourth stage, given that the fuel cell 15 uses the boosted mode of the compressor 16, the general controller 11: - assesses whether one or more of the other sources supplying busbar 12 can support the battery system 14 to increase the electrical power supplying busbar 12, and / or - orders a modification of the power supply via busbar 12 to at least one of the loads.

[0101] Indeed, one or more sources may be saturated and / or faulty and / or limited and / or it may not be desirable to repeatedly call upon another of the power supply sources of the busbar 12. In this case, to support the battery system 14, the general controller 11 orders a modification of the power supply by the busbar 12 of at least one of the loads and in particular orders first a modification of the power supply of at least one of the dissipative loads.

[0102] Preferably, the general controller 11 first orders a change in the power supply to at least one of the priority 1 dissipative loads.

[0103] In particular, the general controller 11 orders a reduction in the power supply to at least one of the priority 1 dissipative loads. Here, the general controller 11 orders a reduction in the power supply to the additional bus 29 while ensuring of course that the voltage across the terminals of the additional bus 29 remains itself within a predefined operating range according to the standards provided by the manufacturer's data for the electrical system 10. To this end, the general controller 11 transmits a corresponding instruction to the controller 31 so that the latter reduces the electrical power transmitted to the additional bus.

[0104] Thus, the voltage across the terminals of the busbar 12 is regulated without completely shedding the loads.

[0105] If modifying the power supply to all priority 1 dissipative loads is not sufficient to support the stack system 14, the general controller 11 orders a modification of the power supply to at least one of the priority 2 dissipative loads.

[0106] In particular, the general controller 11 orders a cut-off or a reduction in the power supply to at least one of the priority 2 dissipative loads.

[0107] For this purpose, the general controller 11 transmits a corresponding instruction to the controller 37 so that the latter reduces the electrical power transmitted to the load 35 and / or commands one of the contactors to temporarily cut off the supply to one of the loads 34 and / or 35.

[0108] It is noted that the priority 2 dissipative loads have a relatively slow response time (to a change in their electrical supply) compared to the response time of the electrical system 10 to meet the demand for increased electrical power to be supplied to the busbar 12. Indeed, the priority 2 dissipative loads are regulated in pressure, temperature, flow rate... and their regulation time constants are slower than the voltage regulation time constant of the busbar 12.

[0109] Consequently, a temporary interruption of their supply or a temporary reduction of their supply (the time for the electrical system 10 to respond to the demand for increased electrical power to be supplied to the busbar 12 and for example the time for the battery system 14 to reach its electrical power setpoint transmitted by the general controller 11) will have little or no effect on their operation.

[0110] If changing the power supply to all priority 1 dissipative loads and all priority 2 dissipative loads is not sufficient to support the stack system 14, then the general controller 11 orders a change in the power supply to at least one of the generating loads.

[0111] In particular, the general controller 11 orders a reduction in the power supply to at least one of the regenerative loads and / or orders at least one of the regenerative loads to reverse its mode of operation to temporarily become an additional power source for the busbar 12. For example, the rotating load can temporarily act as a brake and thus convert the braking energy into electrical energy transmitted to the busbar 12. To this end, the general controller 11 transmits a corresponding instruction to the controller 28 so that the latter reduces the electrical power transmitted to the load 26 or commands one of the contactors to temporarily cut off the power supply to the load 26 or transmits a corresponding instruction to the controller 28 so that the latter reverses the direction of operation of the load 26, which then becomes a source.

[0112] Furthermore, when the difference between the setpoint for the electrical power to be generated by the fuel cell 15 and the electrical power already generated by the fuel cell 15 falls below a predetermined threshold, the fuel cell controller 17 switches the compressor 16 back to its nominal mode. It then notifies the main controller 11.

[0113] Once the compressor 16 returns to its nominal mode, the main controller 11 commands the various controllers of the electrical system 10 to return to the initial configuration in terms of power supply to the loads. To this end, the main controller 11 first orders a gradual return to the initial power supply of the regenerative loads, then of the level 2 dissipative loads, and finally of the level 1 dissipative loads.

[0114] Thus, the voltage of the busbar 12 is regulated in the electrical system 10 by controlling the consumption of the loads connected to the busbar 12 when the sources that can assist the battery system 15 are not available or are saturated or are limited, and for example limited in certain frequency ranges, or when it is not desired to activate them.

[0115] Therefore, the electrical system 10, and in particular its busbar 12, can operate under optimal conditions (especially in terms of stability) while striving to preserve the power supply to the most critical loads, which are more susceptible to changes in their power supply. Furthermore, any change in the power supply to one or more loads is only temporary.

[0116] What has just been mentioned above is also applicable in the case where the electrical power consumed decreases with respect to the electrical power generated by the sources.

[0117] Thus, in a first step, the general controller 11 estimates the electrical power to be delivered to the loads by the busbar 12 and estimates the electrical power supplied by the different sources to the busbar 12. In the event of a decrease in the electrical power consumed by the loads, the general controller 11 preferably transmits to the battery system 14 a setpoint of an electrical power to be reached to compensate for this demand from the loads.

[0118] In a second step, the fuel cell controller 17, knowing the electrical power already generated by the fuel cell 15 and receiving the electrical power setpoint from the general controller 11, estimates whether the fuel cell 15 alone can reach the setpoint in a time interval that is equal to or less than a predetermined time interval.

[0119] In a third step, if the fuel cell controller 17 determines that the fuel cell 15 cannot reach the power setpoint on its own within the predetermined time interval, it informs the general controller 11. The latter: - assesses whether one or more of the other sources supplying busbar 12 can support the battery system 14 by reducing the electrical power supplying busbar 12, and / or - orders a modification of the power supply via busbar 12 to at least one of the loads.

[0120] Thus, to support the stack system 14, the general controller 11 can order a change in the power supply by the busbar 12 of at least one of the loads and in particular first orders a change in the power supply of at least one of the dissipative loads.

[0121] Preferably, the general controller 11 first orders a change in the power supply to at least one of the priority 1 dissipative loads.

[0122] In particular, the general controller 11 orders an increase in the power supply to at least one of the priority 1 dissipative loads. Here, the general controller 11 orders an increase in the power supply to the additional bus 29 while ensuring, of course, that the voltage across the bus The additional bus 29 remains within its predefined operating range. To this end, the main controller 11 transmits a corresponding instruction to the controller 31 so that the latter increases the electrical power transmitted to the additional bus 29.

[0123] Thus, the voltage across the terminals of the busbar 12 is regulated without completely shedding the loads.

[0124] If modifying the power supply to all priority 1 dissipative loads is not sufficient to support the stack system 14, the general controller 11 orders a modification of the power supply to at least one of the priority 2 dissipative loads.

[0125] In particular, the general controller 11 orders an increase in the power supply to at least one of the priority 2 dissipative loads.

[0126] For this purpose, the general controller 11 transmits a corresponding instruction to the controller 37 so that the latter increases the electrical power transmitted to the load 35.

[0127] It is recalled that priority 2 dissipative loads have a relatively slow response time (to a change in their electrical supply) compared to the response time of the electrical system to meet the demand for a reduction in electrical power to be supplied to the busbar 12. Indeed, priority 2 dissipative loads are regulated in pressure, temperature, flow rate... and their regulation time constants are thus slower than the voltage regulation time constant of the busbar.

[0128] Consequently, a temporary increase in their supply (the time for the electrical system 10 to respond to the demand for reduced electrical power to be supplied to the bus bar 12 and for example the time for the battery system 14 to reach its electrical power setpoint transmitted by the general controller 11) will have little or no effect on their operation.

[0129] If modifying the power supply to all priority 1 dissipative loads and all priority 2 dissipative loads is not sufficient to support the stack system 14, then the general controller 11 orders a modification of the power supply to at least one of the regenerative loads.

[0130] In particular, the general controller 11 orders an increase in the power supply to at least one of the regenerative loads. To this end, the general controller 11 transmits a corresponding instruction to the controller 28 so that the latter increases the electrical power transmitted to the load 26.

[0131] Furthermore, when the difference between the setpoint for the electrical power to be generated by the fuel cell 15 and the electrical power already generated by the fuel cell 15 falls below a predetermined threshold, the general controller 11 commands the various controllers of the electrical system 10 in order to return to the initial configuration in terms of power supply to the loads. To this end, the general controller 11 first orders a return to the initial power supply of the regenerative loads, then of the level 2 dissipative loads, and finally of the level 1 dissipative loads.

[0132] With reference to [Fig.3b], in addition to what has been indicated, the electrical system 10 and in particular its battery system 14 is capable of operating according to the first configuration indicated above and also according to a second configuration described below.

[0133] In this second configuration, the electrical system 10 is able to anticipate at least one future demand from the loads leading to a future increase in the electrical power they consume.

[0134] If such a demand is anticipated, then the stack controller 17 commands the compressor 16 to increase its operating point from the current operating point P to a higher operating point P' and thus increase the compressed air flow rate produced by the compressor 16. It is therefore understood that the operating point P' of the compressor 16 exceeds the operating point P which is actually required for the current demand on the loads. The compressor 16 is then said to be overloaded (temporarily, as will be seen later).

[0135] Furthermore, a bypass valve 38 of the stack system 14 (better known as a "bypass valve") is opened to contain the additional influx of compressed air from the compressor 16 due to the overload of the compressor 16.

[0136] This makes it possible to maintain the same operating point of the fuel cell 15 despite the overload of the compressor 16. The excess compressed air is discharged through the valve 38 and is not transmitted to the stack of the fuel cell 15 so that the electrical power it transmits to the electrical system remains unchanged.

[0137] The control of the compressor 15 and that of the valve 38 are preferably coordinated and ensured by the stack controller 17.

[0138] During the actual call, the valve 38 is closed and the additional compressed air previously stored is thus transmitted to the fuel cell 15. The fuel cell controller 17 controls the flow of hydrogen transmitted to the fuel cell 15 so that it can reach a new stabilized operating point.

[0139] In this way, the stack system 14 reaches the setpoint for increasing electrical power to be supplied to the busbar 12 more quickly. In particular, the system 14 instantly increases the electrical power it supplies to the busbar 12.

[0140] Advantageously, at the time of actual activation, the compressor 16 is already at a higher operating speed and the additional electrical energy required for its speed increase has been able to be smoothed over time.

[0141] The compressor 16 can optionally then be switched into its boosted mode to implement the first configuration described above or be kept in its nominal mode.

[0142] The second configuration can thus be controlled by the general controller 11 and / or the stack controller 17 (for example this second configuration can be managed solely by the stack controller 17 if it has the information of the anticipated load call as illustrated in [Fig.3a]).

[0143] Of course, the invention is not limited to the embodiment described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0144] The aircraft could be a drone, an airplane, a helicopter...

[0145] Although here the bus bar is supplied by at least three or at least four sources, the bus bar may be supplied by fewer or more sources. For example, the bus bar may not be supplied by a particular electrical machine connected to a turbomachine. If a turbomachine is present (in the aircraft and / or as a source for the bus bar), the turbomachine may be a turbofan engine, a single-flow turbofan engine, a turbofan engine with more than two cylinders, a hybrid turboprop, a hybrid turbojet, etc. For example, the bus bar may not be supplied by an external power source. For example, the bus bar may be supplied by two or more electrical machines, instead of one as indicated.

[0146] The electrical system may differ from what has been indicated and may include, for example, at least one AC busbar. The electrical system may thus include at least one AC channel. The electrical system will thus control the voltage of the busbar in amplitude when the busbar is operating on direct current, and the electrical system will thus control the voltage of the busbar in both amplitude and frequency when the busbar is operating on alternating current.

[0147] The electrical system may first control one or more other sources to satisfy an increase in electrical power consumed by the loads before turning to the battery system.

[0148] The management system may include a greater number of busbars than indicated, each busbar then being controlled by the general controller as indicated above with load supply control if the sources cannot cope with an increase in the electrical power consumed by the loads.

[0149] The loads may be of any type and may, for example, have propulsive functions (powering one or more electric motors, assisting the starting of at least one turbomachine, etc.) or non-propulsive functions (powering an internal aircraft device such as a set of entertainment screens installed on the passenger seats, etc.). The number of loads and / or the number of load categories may differ from what has been indicated.

[0150] If several regenerative loads are connected to the bar, the power supply of at least two different regenerative loads may be managed by a common controller between the two regenerative loads and / or said loads may themselves be classified into at least two different priority categories, the loads belonging to the first category being those whose power supply is the first to be modified.

[0151] Although here the electrical system and in particular its battery system operates according to a second configuration only in the event of anticipation of an increase in electrical power consumed, the electrical system and its battery system may operate according to the second configuration even without such anticipation - for example to provision an additional capacity of electrical power that can be delivered by the battery system.

[0152] At least one of the described contactors may be of the on / off type or may be a contactor controllable for example by a solid-state power controller (better known by the English acronym SSPC).

Claims

Demands

1. A method for regulating the voltage of at least one busbar (12) of an electrical system, the busbar being supplied by at least one source, the source being a fuel cell system (14) comprising at least one fuel cell (15) and a compressor (16) associated with the fuel cell, the busbar also supplying loads including at least one dissipative load, the method comprising the steps of: - Given a characteristic quantity of an electrical current generated by the fuel cell system and a setpoint of a characteristic quantity of an electrical current to be generated by the fuel cell system resulting in an increase in power to be delivered by the fuel cell system, estimating whether the fuel cell can reach the setpoint in a time interval that is equal to or less than a predetermined time interval,- If the fuel cell cannot reach the setpoint within a time interval equal to or less than a predetermined time interval, switch the compressor from nominal mode to doped mode if it was not already in doped mode. - If the compressor is switched to doped mode, command a change in the power supply to at least one of the loads, starting first with said at least one dissipative load.

2. A method according to claim 1, wherein the loads supplied by the bar comprise at least one regenerative load, and wherein a change in the power supply to said at least one dissipative load is commanded first before a change in the power supply to said at least one regenerative load is commanded.

3. A method according to any one of claims 1 or 2, wherein the dissipative loads are classified into at least two different priority categories, the dissipative loads belonging to the first category being those whose power supply is modified first.

4. A method according to claim 3, comprising the step of grouping the dissipative charges belonging to the first category into at least a group which is connected to a secondary busbar (29), itself connected to the busbar (12) via an electronic power converter (30).

5. Method according to claim 4, comprising the step of lowering a voltage across the terminals of the secondary busbar (29) to modify the power supply provided to the group by the busbar (12).

6. A method according to any one of claims 1 to 5, also comprising the steps of: - Given a characteristic quantity of an electrical current generated by the fuel cell system (14) and a setpoint of a characteristic quantity of an electrical current to be generated by the fuel cell system resulting in a decrease in power to be delivered by the fuel cell system, estimating whether the fuel cell (15) can reach the setpoint in a time interval that is equal to or less than a predetermined time interval, - If the fuel cell cannot reach the setpoint in a time interval that is equal to or less than a predetermined time interval, commanding a change in the electrical supply to at least one of the loads, starting first with the dissipative load(s).

7. A method according to any one of the preceding claims, wherein if the time interval is greater than the predetermined time interval, at least one other source is relied upon to supply the busbar (12).

8. A method according to any one of the preceding claims, comprising the step of associating with the busbar at least one additional source, the additional source being an energy storage device (20).

9. Electrical system (10) configured to implement the method according to any one of the preceding claims, the electrical system thus comprising a busbar (12) and at least one source supplying the busbar, the source being a fuel cell system (14) comprising at least one fuel cell (15) and a compressor (16) associated with the fuel cell, the busbar also supplying loads of which at least one dissipative load.

10. Aircraft (A) comprising at least one electrical system (10) according to claim 9.

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