method and system for rapid starting of a combustion engine in a multi-engine aircraft

Abstract

The present invention relates to an electrical starting and generating system (55) for a main engine (11). A starter-generator (FSG) comprises a first winding (61) and a second polyphase winding (62) jointly setting in motion a transmission shaft (600) in a starting mode, the electrical starting and generating system (55) comprising a first main electrical energy source (65) connected on command by a first electrical connection (66) at least to a first main electrical converter (68) electrically connected to the first winding (61) and a second main electrical energy source (DCGEN) connected on command by a second electrical connection (71) at least to a second main electrical converter (72) electrically connected to the second winding (62). Abstract figure: figure 1

Description

Title of the invention: method and system for rapid starting of a combustion engine in a multi-engine aircraft

[0001] The present invention relates to a method and a system for rapid starting of a combustion engine within a multi-engine aircraft.

[0002] An aircraft may comprise several combustion engines for moving a mechanical system, and for example a mechanical system rotating at least one rotor on a helicopter.

[0003] The combustion engines may take the form of a turboshaft engine, possibly a free turbine engine. A free turbine turboshaft engine comprises a gas generator provided with a compressor, a combustion chamber and a high-pressure expansion assembly integral in rotation with the compressor. The compressor may be provided with one or more compression stages. Similarly, the expansion assembly may comprise one or more expansion turbines. In addition, the free turbine turboshaft engine comprises at least one low-pressure working turbine referred to as "free", namely mechanically independent in rotation from the compressor of the high-pressure expansion assembly, rotating a power shaft.

[0004] Furthermore, the power plant comprises a motor starting system equipped with a generator / starter. A generator / starter comprises an electrical machine mechanically connected to a moving assembly of the associated engine. In the presence of a turboshaft engine, the electrical machine comprises a shaft integral in rotation with the compressor and the high pressure expansion assembly of the gas generator.

[0005] Such an electric machine can operate in an electric motor mode and in an electric generator mode. When the electric motor mode is applied, the electric machine transforms electrical energy received from a source into mechanical energy to participate in setting in motion the moving assembly of the associated combustion engine, for example during a start-up phase. When the electric generator mode is applied, the electric machine transforms mechanical energy taken from the associated combustion engine into electrical energy that can be transmitted to an electrical network of the aircraft.

[0006] Thus, a rotary wing aircraft may comprise a power plant having several combustion engines for setting in motion a power transmission chain, this power transmission chain in particular setting in rotation at least one rotary wing.

[0007] The power plant may optionally operate in an asymmetrical operating mode by putting one of the engines on standby during certain phases of operation of the aircraft.

[0008] On a rotary wing aircraft, during the asymmetric mode, at least one active engine is regulated to ensure the rotation of the rotary wing by developing with its power shaft a non-zero active driving power. At least one passive engine is on the other hand put on standby, for example by being switched off or regulated to develop with its power shaft an idle power lower than the active driving power. The combustion chamber of the passive engine can be supplied with fuel, or is not supplied with fuel. The passive engine is further desynchronized from the rotary wing by means of a freewheel.

[0009] In such an asymmetric mode, if a failure occurs and causes the active engine to stop, the standby engine must be reactivated quickly.

[0010] Therefore, the generators / starters are designed to achieve a reasonable start-up time with a usual level of availability during the initial start-up of ground-based combustion engines, and a fast start-up time with a high level of availability for reactivating a standby engine.

[0011] The combination of the start-up time constraints and the electrical voltage value of the electrical network electrically supplying the electrical machine can lead to a start-up system having a significant mass.

[0012] Document FR3121293 describes a power plant equipped with a combustion engine and an electric starter. The power plant also has a main electrical energy source which may, for example, comprise an electric battery, and a secondary electrical energy source which may also, for example, comprise an electric battery. A connector then electrically connects the main electrical energy source and the secondary electrical energy source in series to the electric starter during a rapid start phase.

[0013] Document FR3019214 describes an electrically independent starting system for an on-board network for starting two turbine engines of an aircraft. According to one embodiment, this starting system comprises a first electrical machine connected to a first turbine engine and a second electrical machine connected to a second turbine engine. The first electrical machine is electrically connected to a first direct current / alternating current type electrical converter by a first electrical connector and to a second direct current / alternating current type converter by a second electrical connector. Similarly, the second electrical machine is electrically connected to the first converter by a third electrical connector and to the second converter by a fourth electrical connector. The first electrical converter is in further electrically connected to a first electrical source via a first direct current bus, and the second electrical converter is electrically connected to a second main electrical power source via a second direct current bus.

[0014] The present invention therefore aims to propose an innovative starting and electrical generation system for a multi-engine aircraft, possibly making it possible to obtain a reasonable engine starting time with a usual level of availability during the initial start-up of combustion engines on the ground, and / or a rapid starting time with a high level of availability to reactivate an engine on standby when applying an asymmetrical operating mode.

[0015] The invention thus relates to a starting and electrical generation system for a main combustion engine of an aircraft, the starting and electrical generation system comprising a generator-starter provided with a transmission shaft, the generator-starter being able to operate in a motor mode to set in motion a main moving assembly of the main engine with the transmission shaft and a generator mode to generate electrical energy by having the transmission shaft set in motion by said main moving assembly.

[0016] The generator-starter comprises a first polyphase winding and a second polyphase winding generating magnetic fields to create respective motor torques jointly setting the transmission shaft in motion in a starting mode of the motor mode, the starting and electrical generation system comprising a first main electrical energy source connected on command by a first electrical connection at least to a first main electrical converter electrically connected to the first winding and a second main electrical energy source connected on command by a second electrical connection at least to a second main electrical converter electrically connected to the second winding.

[0017] The first polyphase winding and the second polyphase winding are polyphase coil assemblies. The first polyphase winding and the second polyphase winding therefore each comprise several electrical coils.

[0018] As a result, the generator-starter is electrically powered during the starting mode by two reversible electrical converters of the direct current / alternating current type, directly, i.e. without passing through an electrical connection / disconnection member. The two electrical converters are connected on command, via electrical connection / disconnection members, to two separate and independent electrical sources. These electrical sources may already be present on a conventional aircraft, and may not induce an increase in mass.

[0019] Furthermore, this use of two windings electrically powered in parallel, or even independently depending on the variant, makes it possible to sum the electromagnetic torques produced for driving the transmission shaft. Therefore, the transmission shaft can develop significant mechanical power. With such significant mechanical power, starting the main engine can be rapid, namely a start obtained in less than 10 seconds for example. Such rapid starting is particularly advantageous in flight when the main engine is on standby within a multi-engine aircraft, for example when the asymmetric mode described above is applied.

[0020] In the event of a fault on one of the electrical power supply lines electrically supplying the first winding and the second winding, the other electrical power supply line and the other winding make it possible to obtain sufficient mechanical power to start the main engine in a degraded mode. Such a fault may be a clear electrical short circuit, and for example may result from a short circuit directly between the phases of a winding. The system is therefore secure and offers the possibility of starting the engine with a high level of availability, particularly in flight.

[0021] Indeed, each winding is sized to obtain alone, and even in the presence of a braking torque generated by the other winding due to a short-circuit current for example between the phases of this other winding, a mechanical power allowing the main motor to start.

[0022] Thus, the electrical starting and generation system uses two separate, segregated electrical energy sources, possibly of different natures and / or already used elsewhere on the aircraft, to electrically power a generator-starter during starting. This architecture makes it possible to obtain a restart time / mass / reliability compromise that is interesting for the intended functions.

[0023] The starting and electrical generation machine may be a pure starter which can only operate in engine mode, for example to start a powerful engine requiring significant mechanical power.

[0024] The electrical starting and generation system can also generate electrical energy during an electrical energy production mode by converting mechanical energy taken from the main engine in operation. The starter-generator can then become a source of regulated electrical voltage, for example 28 Volts. In this operating mode, the two electrical converters are used in parallel in order to use the entire available copper volume, namely that of the first and second windings, and thus optimize the mass of the system.

[0025] Optionally, the two electrical converters are requested to respectively electrically supply two separate electrical networks. According to one example, the two electrical converters electrically supply a normal electrical network and an emergency electrical network.

[0026] According to another example, the two electrical converters electrically supply two separate networks with different electrical voltages. For example, one electrical converter supplies an electrical network having an electrical voltage of 28 Volts and the other electrical converter supplies an electrical network having an electrical voltage of 56 Volts, for example, to supply flight control actuators, for example.

[0027] The electrical starting and generation system may further comprise one or more of the following features.

[0028] According to one possibility, the first winding and the second winding may be different, for example by having different numbers of winding turns which generates different inductances.

[0029] Thus, each winding can be adapted to the associated main electrical energy source, in particular if they are different and / or have characteristics, for example different electrical voltages.

[0030] According to a possibility compatible with the preceding ones, the first main electrical energy source may not be regulated in electrical voltage and the second main electrical energy source may be regulated in electrical voltage or the first main electrical energy source and the second main electrical energy source may be regulated to different electrical voltages.

[0031] These two alternatives make it possible to control the engine torque transmitted to the main electrical machine.

[0032] According to a possibility compatible with the previous ones, the first main source of electrical energy may comprise at least one electric battery or a thermal battery or a supercapacitor.

[0033] The main electrical energy source may comprise several of these unregulated electrical energy storage means, which makes it possible not to have to oversize an electrical energy storage means to support start-up.

[0034] Such an electric battery is usually present on an aircraft.

[0035] According to a possibility compatible with the previous ones, the second main source of electrical energy can comprise an electrical generator regulated in electrical voltage and configured to be mechanically set in motion by a mechanical system.

[0036] Such an electric generator is usually present on an aircraft.

[0037] According to a first alternative of the generator / starter, this generator / starter may comprise an electrical machine having a stator provided with the first winding and the second winding which are polyphase as well as with floating neutral and galvanically isolated from each other, the electrical machine comprising a rotor with buried permanent magnets with variable reluctance integral in rotation with the transmission shaft.

[0038] The use of two windings electrically powered in parallel makes it possible to sum the electromagnetic torques produced on the buried permanent magnet rotor with variable reluctance. In the event of a fault on one of the electrical supply lines electrically supplying the two stator windings, the use of a buried permanent magnet rotor with variable reluctance makes it possible to limit the short-circuit current possibly produced. Such an electrical machine makes it possible to reduce short-circuit currents at high speed, and therefore limits the braking torque produced and heating of the electrical machine in the event of an internal short circuit. Therefore, the other electrical supply line and the other stator winding can make it possible to obtain sufficient mechanical power to start the main motor in a degraded mode. The generator / starter is therefore robust and has a high level of reliability.

[0039] According to a second alternative of the generator / starter, this generator / starter can comprise a double electrical machine with separate excitations, the double electrical machine with separate excitations comprising a stator provided with the first winding and the second winding, the double electrical machine with separate excitations comprising a rotor provided with two rotor windings electrically connected to an electrical collector with brushes.

[0040] The two rotor windings cooperate respectively with the first and second windings of the stator. An internal short-circuit case is managed by cutting off the excitation concerned, the braking torque resulting from the short-circuit then being eliminated. The generator / starter therefore has a high level of reliability.

[0041] According to a third alternative of the generator / starter, this generator / starter may comprise a magnet starter and an electrical machine operating in generator mode and in motor mode, the magnet starter being provided with a first stator having the first winding and a first rotor which is mechanically connected to the transmission shaft by a freewheel, the electrical machine comprising a second stator provided with the second winding and a second rotor secured to the transmission shaft, the electrical machine being able to be an electrical machine with separate excitation or asynchronous.

[0042] Thus, the starter is only used during a starting phase, while the electrical machine is used both during a starting phase and during the electrical energy production mode. The freewheel makes it possible to isolate the starter of the electric machine in the event of a short circuit within one of these components. In the presence of an electric machine with separate excitation, cutting off the excitation can eliminate a possible short circuit. The generator / starter therefore has a high level of reliability.

[0043] According to a fourth alternative of the generator / starter, this generator / starter can comprise a double asynchronous electrical machine comprising a stator provided with the first winding and the second winding.

[0044] The internal short circuit is managed by taking into account the internal residual electrical voltages of the machine.

[0045] According to a fifth alternative of the generator / starter, this generator / starter may comprise a separately excited electrical machine comprising a stator having one winding among the first winding and the second winding and an asynchronous electrical machine comprising a stator having the other winding among the first winding and the second winding.

[0046] Whatever the nature of the generator / starter, according to a possibility compatible with the previous ones, the starting and electrical generation system can include a manager configured to:

[0047] - in a starting mode, electrically supply the first winding via the first main electrical converter with at least the first main electrical energy source, electrically supplying the second winding via the second main electrical converter with at least the second main electrical energy source,

[0048] - in a standby mode, power one of the first winding and second winding with the second main electrical energy source, maintaining the charge of the first main electrical energy source via a transverse electrical connection connected to the second electrical connection,

[0049] - in an electrical energy producing mode, electrically connect in parallel the second main electrical converter and the first main electrical converter to supply electrical power to the first main electrical power source.

[0050] The term "manager" designates a system for carrying out the various aforementioned actions. The manager may comprise at least one electrical core, electronic equipment of the generator / starter, a computer, contactors controlled to open or close an electrical connection, etc.

[0051] According to a possibility compatible with the previous ones, the second electrical connection can comprise a main bus, and the manager can comprise:

[0052] - a controller,

[0053] - a first main contactor controlled by the controller and arranged on the first electrical connection,

[0054] - a second main contactor controlled by the controller and arranged on the second electrical connection between the main bus and the second main electrical converter.

[0055] The first contactor and the second contactor allow the main electrical converters to be electrically connected, if necessary, to the main electrical energy sources.

[0056] Optionally, the manager may include:

[0057] - a third main contactor controlled by the controller and arranged between the main bus and a connection configured to be electrically connected to a complementary electrical connection of an additional electrical circuit,

[0058] - a fourth main contactor controlled by the controller and arranged on a transverse electrical connection, the transverse electrical connection extends from the second electrical connection to the first electrical connection between the first main contactor and the first main electrical energy source,

[0059] - a fifth main contactor controlled by the controller and arranged on a electrical line connecting the first electrical connection and the second electrical connection between on the one hand the second main contactor and the second main electrical converter and on the other hand between the first main contactor and the first main electrical converter.

[0060] These various contactors make it possible to implement the various operating modes mentioned above.

[0061] According to a variant, the third main contactor is arranged on the second electrical connection, an additional contactor being able to be arranged between the third main contactor and the second source of electrical energy.

[0062] According to another variant allowing the main electrical energy sources to be connected in parallel, an additional electrical connection connects the first electrical connection and the second electrical connection. This additional electrical connection is connected to the second electrical connection between the second main electrical energy source and the main bus, and to the first electrical connection between the first main electrical energy source and the first main contactor. In addition, the first electrical connection comprises an additional contactor between its connection to the additional electrical connection and its connection to the transverse electrical connection.

[0063] According to a possibility compatible with the previous ones, the first main electrical energy source and the second main electrical energy source can have different electrical voltages.

[0064] The invention further relates to an aircraft equipped with a main combustion engine and at least one additional combustion engine connected to a mechanical system setting in motion at least one rotary wing or a rotor or a propeller, the additional engine being connected to an additional electrical machine capable of operating in a motor mode for setting in motion an additional mobile assembly of the additional engine and a generator mode for generating electrical energy by being set in motion by said additional mobile assembly, the additional electrical machine being electrically connected to an additional electrical converter which is connected by an additional electrical connection to an additional source of electrical energy.

[0065] This aircraft includes a starting and electrical generation system of the type described above for the main engine.

[0066] According to one possibility, the mechanical system may comprise a power transmission box connected to the main motor and the additional motor, the second main electrical energy source may be set in motion by the power transmission box.

[0067] The power transmission box may be mechanically connected to a rotary wing, and / or a propeller, and / or a yaw movement control rotor for example.

[0068] Furthermore, the invention also relates to a method for starting a combustion engine and generating electrical energy with a starting and electrical generation system of the type described above.

[0069] This method comprises:

[0070] - a starting mode comprising the following steps: electrically supplying the first winding via the first main electrical converter with at least the first main electrical energy source, electrically supplying the second winding via the second main electrical converter with at least the second main electrical energy source,

[0071] - a standby mode comprising the following steps: powering one of the first winding and second winding with the second main electrical energy source and maintaining the charge of the first main electrical energy source via a transverse electrical connection connected to the second electrical connection,

[0072] - an electrical energy production mode comprising the following steps: electrically connecting in parallel the second main electrical converter and the first main electrical converter and connecting them to the first main electrical energy source.

[0073] The invention and its advantages will appear in more detail in the context of the description which follows with examples given for illustrative purposes with reference to the appended figures which represent:

[0074] [Fig.l], a starting and electrical generation system for a stationary main engine,

[0075] [Fig.2], an example of a starter-generator according to the invention,

[0076] [Fig.3], an example of a starter-generator according to the invention,

[0077] [Fig.4] an example of a starter-generator according to the invention.

[0078] [Fig.5], the starting and electrical generation system of [Fig.l] during a starting mode,

[0079] [Fig.6], the starting and electrical generation system of [Fig.l] during a standby mode,

[0080] [Fig.7], the starting and electrical generation system of [Fig.l] during an electrical energy producing mode,

[0081] [Fig.8], a starting and electrical generation system with parallel electrical energy sources during a standby mode,

[0082] [Fig.9], the starting and electrical generation system of [Fig.8] during a starting mode, and

[0083] [Fig.10], the starting and electrical generation system of [Fig.8] during an electrical energy production mode,

[0084] Elements present in several distinct figures are assigned a single reference.

[0085] [Fig.l] shows a starting and electrical generation system 55 for a main combustion engine 11 of an aircraft 1.

[0086] Such an aircraft 1 thus comprises a power plant equipped with the main engine 11, or even at least one additional combustion engine 12. The reference 10 designates any combustion engine, the references 11, 12 respectively designating a main engine and an additional engine if necessary to identify a specific engine 10.

[0087] The main engine 11 and the possible additional engine(s) 12 may be controlled by respective engine control systems 101, 102. Each engine control system 101, 102 may be of a conventional type, and may thus comprise a fuel metering device and various sensors connected to an engine computer, the engine computer being configured to control the fuel metering device at least as a function of a signal emitted by one or more sensors. The engine control systems are not described in more detail so as not to burden the present description, these engine control systems being well known to those skilled in the art.

[0088] According to one example, at least one engine 10 may be a turbine engine. For example, the main engine 11 comprises a turbine engine equipped with a gas generator 15. The gas generator 15 has at least one compression turbine 16, a combustion chamber 17 into which the fuel is injected and at least one expansion turbine 18 connected in rotation to the compression turbine(s) 16. The compression turbine(s) 16 are mechanically connected in rotation to the expansion turbine(s) 18 to form a main moving assembly 14. In addition, the turbine engine may comprise at least one free turbine 19 which directly or indirectly sets in motion a power shaft 21 of the engine.

[0089] Similarly, the additional engine 12 may be a turboshaft engine equipped with an additional mobile assembly 140 and a power shaft 22. The reference 20 designates any power shaft, the references 21, 22 designating particular power shafts respectively of the two engines 11, 12.

[0090] Regardless of the type of motors, each motor 10 therefore comprises a power shaft 20 and a mobile assembly 14, 140.

[0091] Furthermore, the power shaft(s) 20 are mechanically connected to a mechanical system 25 to set it in motion. For example, the mechanical system 25 may be connected to at least one rotating aerodynamic member 5. This rotating aerodynamic member 5 may in particular be a rotary wing according to the example, a yaw movement control rotor or a propeller.

[0092] By way of illustration, the mechanical system 25 may be provided with a power transmission box 26 which is mechanically interposed between the engines 10 and the rotary wing 5. For example, the power transmission box 26 comprises a rotor mast 35, provided with one or more collinear shafts 36, 37 connected to the rotating aerodynamic member 5. The power transmission box 26 may be provided with an input shaft 30 per engine 10 and various gears arranged between the input shafts 30 and the rotor mast 35. According to an example given by way of illustration, each input shaft 30 is engaged on a large wheel 40. This large wheel 40 is then mechanically connected by an internal shaft 41 to a planetary pinion 46 of a power reduction stage 45. Planetary pinions 47 are then engaged with a starts on the planetary pinion 46 and on a toothed crown 48 stationary in the reference frame of the aircraft 1.In addition, the planet gears 47 are carried by a planet carrier 49 integral in rotation with the rotor mast 35. Therefore, each input shaft 30 is driven in rotation by a power shaft 20 of a motor 10 directly or via a respective mechanical input chain. The mechanical system 25, and according to the example illustrated a mechanical input chain, may comprise at least one freewheel 51, and / or at least one connecting shaft 52, and / or at least one connector allowing misalignments... .

[0093] The literature describes various types of power transmission boxes and various kinematic chains, the example described being given solely for illustrative purposes.

[0094] Regardless of the nature of the mechanical system 25 and the presence or absence of one or more additional motors 12, the electrical starting and generation system 55 comprises a generator / starter FSG capable of operating in a motor mode MOT to set in motion the main moving assembly 14 of the main motor 11 and a generator mode GEN to generate electrical energy by being set in motion by said main moving assembly 14.

[0095] Thus, the generator / starter FSG comprises a transmission shaft 600 connected to the main mobile assembly 14.

[0096] Furthermore, the FSG starter-generator comprises a first polyphase winding 61 and a second polyphase winding 62. The coils of the first winding 61 and second winding 62 are electrically connected respectively to a first main electrical converter 68 and to a second main electrical converter 72.

[0097] When the first winding 61 and the second winding 62 are electrically powered, the first winding 61 and the second winding 62 create magnetic fields jointly setting the transmission shaft 600 in rotation. Conversely, during the generator mode GEN, the transmission shaft 600 is set in motion by the main moving assembly 14, which makes it possible to generate electrical energy.

[0098] Such a generator / starter FSG allows the implementation of various operating modes. These operating modes include: i) a MODRAP starting mode during which the first winding 61 and the second winding 62 are electrically powered to jointly drive the transmission shaft 600 in rotation, ii) a MODVEIL standby mode during which only one of the first winding 61 and second winding 62 is electrically powered to drive the transmission shaft 600 in rotation, iii) an energy producing mode MODPROD during which the first winding 61 and the second winding 62 generate electrical energy when the transmission shaft 600 is driven in rotation by the main motor 11, via the main moving assembly 14.

[0099] Figures 1 to 4 illustrate various embodiments of an FSG generator / starter.

[0100] According to [Fig.l], the generator / starter FSG comprises an electrical machine 59 having a stator 60 provided with the first winding 61 and the second winding 62. The first winding 61 and the second winding 62 are for example three-phase, with floating neutral and galvanically isolated from each other. In addition, the electrical machine 59 comprises a rotor 64 with buried permanent magnets 640 with variable reluctance secured to the transmission shaft 600. The permanent magnets 640 are embedded in the rotor 64.

[0101] According to the schematic example of [Fig.2], the generator / starter FSG comprises a double electrical machine with separate excitations 110. This double electrical machine with separate excitations 110 comprises a stator 111 provided with the first winding 61 and the second winding 62. In addition, the double electrical machine with separate excitations 110 comprises a rotor 112 provided with two rotor windings facing the first winding 61 and the second winding 62. The two rotor windings are electrically connected by an electrical collector with brushes 115 to two additional converters 113, 114 in electrical parallel and respectively to the first and second main converters 68, 72.

[0102] According to the schematic example of [Fig. 3], the FSG generator / starter comprises a conventional magnet starter 120 and an electrical machine 125 operating in generator mode and in motor mode. The magnet starter 120 is then provided with a first stator 121 having the first winding 61 and a first rotor 122 provided with at least one permanent magnet and mechanically connected to the transmission shaft 600 in particular by a freewheel 123, or even via the electrical machine 125. This electrical machine 125 comprises a second stator 126 provided with the second winding 62 and a second rotor 127 secured to the transmission shaft 600, the electrical machine 125 possibly being an electrical machine with separate excitation of the type of [Fig. 2] or asynchronous.

[0103] During the MODRAP starting mode, the magnet starter 120 and the electric machine 125 jointly set the transmission shaft 600 in motion. In the event of failure of one of these two members, the other member ensures starting.

[0104] During the MODVEIL standby mode, only the electrical machine 125 is for example used to set the transmission shaft 600 in motion.

[0105] During the MODPROD energy production mode, only the electric machine 125 produces electrical energy. The magnet starter 120 is then separated from the transmission shaft 600 by the freewheel 123.

[0106] A variant of this embodiment comprises a separately excited electrical machine comprising a stator having one winding among the first winding and the second winding and an asynchronous electrical machine comprising a stator having the other winding among the first winding and the second winding.

[0107] According to the schematic example of [Fig.4], the generator / starter FSG comprises a double asynchronous electrical machine 130. This double asynchronous electrical machine 130 comprises a stator 131 provided with the first winding 61 and the second winding 62. In addition, the double asynchronous electrical machine 130 comprises a rotor 132 secured to the transmission shaft 600. This rotor 132 may be of the type known as a “squirrel cage”.

[0108] Whatever the embodiment of the generator / starter FSG and with reference to [Fig.5] for example, the system 55 may comprise an additional circuit comprising an additional electrical machine SG, for example of the same type as the main electrical machine or of a usual type, connected to the additional motor 12. This additional electrical machine SG may comprise an additional electrical machine 590 connected to an additional converter 591. The additional converter 591 may be connected by an additional electrical connection 98 to an additional electrical energy source 95. For example, the additional electrical energy source 95 comprises at least one electric battery or a thermal cell or an overcapacity. Optionally, the additional electrical energy source 95 is connected to an additional essential on-board electrical network 304 electrically supplying one or more consumers.

[0109] Generally speaking, the expressions “electrical connection” and “electrical line” designate assemblies which may comprise at least one wire or one electrical track, at least one electrical contactor, at least one electrical bus, etc.

[0110] For example, the additional electrical connection 98 comprises an additional electrical core EMB2. This additional core EMB2 comprises an additional bus 971 connected by a first additional contactor K25 to the additional converter 591, and by a second additional contactor K22 to the additional electrical energy source 95. The additional bus 971 can be connected to a complementary electrical connection 88 connected to the electrical circuit cooperating with the generator / starter FSG. This complementary electrical connection 88 is provided with a third additional contactor K23. Finally, the additional bus 971 can be connected to a secondary electrical network 302 of the aircraft 1. The additional contactors K22, K23, and K25 are controlled by standard electronics of the additional electrical core EMB2.

[0111] Whatever the embodiment of the generator / starter FSG and independently of the possible presence of the additional circuit, the electrical starting and generation system 55 comprises a first main electrical energy source 65. The first main electrical energy source 65 is connected on command by a first electrical connection 66 at least to the first main electrical converter 68. Optionally, the first main electrical energy source 65 is connected to a main essential on-board electrical network 303 electrically supplying one or more consumers.

[0112] In addition, the electrical starting and generation system 55 comprises a second main electrical energy source DCGEN. The second main electrical energy source DCGEN is connected on command by a second electrical connection 71 at least to the second main electrical converter 72. Optionally, the second main electrical energy source DCGEN is connected to the two main and additional essential on-board electrical networks 303, 304.

[0113] For example, the second main electrical energy source DCGEN is regulated in electrical voltage. Thus, the second main electrical energy source DCGEN may comprise an electrical generator connected to the mechanical system 25, and possibly to the power transmission box 26 or even to a shaft secured to the large wheel 40 according to the example illustrated.

[0114] Optionally, the first main electrical energy source 65 is not regulated in electrical voltage. For example, the first main electrical energy source 65 comprises an electric battery or a thermal cell or a supercapacitor.

[0115] Alternatively, the first main electrical power source 65 and the second main electrical power source DCGEN may be regulated to different electrical voltages.

[0116] The first electrical connection 66 and the second electrical connection 71 can pass through a main electrical core EMB1.

[0117] According to another aspect, the starting and electrical generation system 55 may comprise a manager 75 configured to apply a method of starting a combustion engine and generating electrical energy of the invention.

[0118] The manager 75 may comprise a controller 76. The controller 76 may comprise at least one processing unit for applying the method of the invention, by means of a software program, a logic circuit or an equivalent. At least one processing unit may comprise one of the following elements: a computer dedicated or not to this application, a first electronics unit 107 of the main electrical core EMB1, a second electronics unit 106 of the generator / starter FSG, and / or a computer of an engine regulation system 101, 102.

[0119] Furthermore, the manager 75 may comprise a human-machine interface 105 allowing a pilot of the aircraft 1 to select the operating mode to be applied, for example from a MODRAP start-up mode, a MODVEIL standby mode, or even a MODPROD electrical energy producing mode. For example, this human-machine interface 105 is in a wired or wireless connection with the controller 76. Optionally, this human-machine interface 105 may comprise a touch screen, a button, a keyboard, etc.

[0120] Optionally, the manager 75 may comprise at least one operating sensor monitoring an operation of the main electrical machine FSG and transmitting a measurement signal to the controller 76. For example, said at least one operating sensor comprises position sensors, electric current measurement sensors, and temperature measurement sensors. The redundancy and dissimilarity of these sensors may make it possible to ensure the nominal operation of the main electrical machine FSG in the event of failure of one or more of them.

[0121] Furthermore, the controller 76 can execute instructions to control the first main electrical converter 68 and the second main electrical converter 72 depending on the mode applied. In motor mode, at least one of the first and second main electrical converters 68, 72 generates a polyphase electrical voltage of variable amplitude and frequency controlled to ensure control of the engine torque produced. The first main electrical energy source 65 and the second main electrical energy source DCGEN can generate distinct electrical voltage values, which means that the control of the first and second main electrical converters 68, 72 is then not synchronous. In generator mode, however, the first and second main electrical converters 68, 72 are used in parallel and are synchronized.

[0122] Furthermore, the manager 75 may comprise a first main contactor Kl 1 controlled by the controller 76 and arranged on the first electrical connection 66 to electrically open or close this first electrical connection 66. For example, the first electrical connection 66 comprises a first upstream wired connection 661 which extends from the first main electrical energy source 65 to the first main contactor Kl 1, and a first downstream wired connection 662 which extends from the first main contactor Kl 1 to the first main electrical converter 68. The terms “upstream” and “downstream” are used to distinguish electrical sections of a connection in a direction chosen for convenience.

[0123] Furthermore, the manager 75 may comprise a second main contactor K15 controlled by the controller 76 and arranged on the second electrical connection 71 to electrically open or close this second electrical connection 71. For example, the second electrical connection 71 comprises a second upstream wired connection 711 which extends from the second main electrical energy source DCGEN to the second main contactor K15, and a second downstream wired connection 712 which extends from the second main contactor K15 to the second main electrical converter 72. Optionally, the second upstream wired connection 711 comprises a main bus 671. The main bus 671 is connected to the second main contactor K15, or even to a connection of the first downstream wired connection 662 which is itself connected to a secondary on-board electrical network 301.

[0124] In addition, the manager 75 may comprise: - a third main contactor Kl3 controlled by the controller 76 and arranged between the main bus 671 and a connection 672 configured to be electrically connected to the complementary electrical connection 88, - a fourth main contactor K12 controlled by the controller 76 and arranged on a transverse electrical connection 96, the transverse electrical connection 96 extending from the second electrical connection 71 to the first connection electrical 66 between the first main contactor Kl 1 and the first main electrical energy source 65, - a fifth main contactor KP controlled by the controller 76 and arranged on an electrical line connecting the first electrical connection 66 and the second electrical connection 71 between on the one hand the second main contactor Kl5 and the second main electrical converter 72 and on the other hand between the first main contactor Kl 1 and the first main electrical converter 68, i.e. between the first downstream wired connection 662 and the second downstream wired connection 712, - a sixth contactor K14.

[0125] The various contactors mentioned may be of a usual type in order to open or close an electrical line, and may be controlled in the usual manner by the controller 76.

[0126] For example, the first main contactor K11, the second main contactor K15, the third main contactor K13, the fourth main contactor K12 and the sixth contactor K14 belong to the main electrical core EMB1 and can be controlled by its electronics 107, while the fifth main contactor KP belongs to the generator / starter FSG and can be controlled by its electronics 106.

[0127] According to the first variant of [Fig.5], the first downstream wired connection 662 comprises only one wired connection connected to the first main electrical energy source 65, to the first main contactor K11, and to the transverse electrical connection 96. In addition, the second upstream wired connection 711 comprises the third main contactor K13 and the sixth contactor K14, this sixth contactor K14 being arranged between the second electrical energy source DCGEN and the third main contactor K13.

[0128] Figures 5 to 7 illustrate various modes of operation of this first variant of the starting and electrical generation system 55 of the invention.

[0129] [Fig. 5] illustrates the starting and electrical generation system 55 of the first variant during a MODRAP starting mode. The controller 76 is configured, during a step STPA1, to electrically supply the first winding 61 via the first main electrical converter 68 only with the first main electrical energy source 65. The controller 76 thus closes the first main contactor K1 1. In parallel, the additional motor 12 may be stopped or broken down for example.

[0130] The controller 76 is also configured, during a step STPA2, to electrically power the second winding 62 via the second main electrical converter 72 only with the second main electrical energy source. DCGEN. Controller 76 thus closes the second main contactor K15, the third main contactor K13 and the sixth contactor K14.

[0131] Therefore, the controller 76 is also configured to control the main electrical machine FSG to operate it in motor mode MOT.

[0132] Optionally, the controller 76 is also configured to open the fourth main contactor K12 and the fifth main contactor KP in order to segregate the first main electrical energy source 65 and the second main electrical energy source DCGEN.

[0133] Under these conditions, the rapid restart of the main engine 11 is obtained by using two different sources of electrical energy 65, DCGEN to respectively electrically supply two electrical converters 68, 72.

[0134] [Fig.6] illustrates the starting and electrical generation system 55 of the first variant during a MODVEIL standby mode.

[0135] During this standby mode MODVEIL, the controller 76 is configured, during a step STPB1, to electrically power the second winding 62 via the second main electrical converter 72 only with the second main electrical energy source DCGEN. The controller 76 thus closes the second main contactor K15, the third main contactor K13 and the sixth contactor K14, and opens the first main contactor K11 as well as the fifth main contactor KP. From then on, the controller 76 is also configured to control the main electrical machine FSG to operate it in engine mode MOT, for example to maintain the main moving assembly 14 at a predetermined rotational speed, the combustion chamber 17 being switched off or supplied with fuel.In parallel, the additional motor 12 can operate normally to set in motion the mechanical system 25, and the additional electrical machine SG can operate in MODGEN generator mode.

[0136] The controller 76 is also configured, during a step STPB2, to maintain the charge of the first main electrical energy source 65 by electrically supplying the first electrical connection 66 with the second main electrical energy source DCGEN. The controller 76 thus closes the fourth main contactor K12.

[0137] [Fig.7] illustrates the starting and electrical generation system 55 of the first variant during a MODPROP electrical energy production mode.

[0138] During this electrical energy producer mode MODPROP, the controller 76 is configured, during a step STPC1, to electrically disconnect the second main electrical energy source DCGEN from the main electrical machine FSG. The controller 76 thus opens the second main contactor K15 and the third main contactor K13.

[0139] The controller 76 is also configured, during a step STPC2, to electrically connect in parallel the second main electrical converter 72 to the first main electrical converter 68, and connect them to the first main electrical energy source 65. The controller 76 thus closes the fifth main contactor KP and the first main contactor K11, and opens the fourth main contactor K12. The controller 76 optionally closes the sixth contactor K14 and the third additional contactor K23.

[0140] Therefore, the controller 76 is also configured to control the main electrical machine FSG to operate it in generator mode GEN. The first and second main electrical converters 68, 72 then deliver electrical energy to the first main electrical connection 66. The second main electrical energy source DCGEN electrically supplies the essential on-board network 303.

[0141] Figures 8 to 10 illustrate a second variant.

[0142] Compared to the first variant, the sixth contactor K14 is moved. According to the second variant and with reference to [Fig.8], the first upstream wired connection 661 comprises the sixth contactor K14, the transverse electrical connection 96 being connected to the first upstream wired connection 661 between the first main electrical energy source 65 and this sixth contactor K14.

[0143] Furthermore, the third main contactor K13 is arranged between the main bus 671 and the complementary electrical connection 88.

[0144] Finally, an intermediate wired electrical connection extends from the second upstream wired connection 711 to the first upstream wired connection 661, between the sixth contactor K14 and the first main contactor K11. For example, the second upstream wired connection 711 comprises a connection, between the main bus 671 and the second main electrical energy source DCGEN, connected to the transverse electrical connection 96 and to the intermediate wired electrical connection.

[0145] During the MODVEIL standby mode illustrated in [Fig.8], the controller 76 is configured to electrically power the first winding 61 via the first main electrical converter 68 with the second main electrical energy source DCGEN. The controller 76 thus closes the first main contactor K11 and opens the second main contactor K15, the sixth contactor K14, and the fifth main contactor KP.

[0146] Therefore, the controller 76 is also configured to control the main electrical machine FSG in order to operate it in engine mode MOT, for example to maintain the main moving assembly 14 at a predetermined rotational speed, the combustion chamber 17 being switched off or supplied with fuel. In parallel, the additional motor 12 can operate normally to set the mechanical system 25, and the additional electrical machine SG can operate in MODGEN generator mode.

[0147] The controller 76 is also configured to maintain the charge of the first main electrical energy source 65 by electrically supplying the first electrical connection 66 with the second main electrical energy source DCGEN. The controller 76 thus closes the fourth main contactor K12. Optionally, the controller 76 also closes the third main contactor K13.

[0148] [Fig.9] illustrates the starting and electrical generation system 55 of the second variant during a MODRAP starting mode. The controller 76 is configured to electrically power the first winding 61 via the first main electrical converter 68 with the first main electrical energy source 65 and the second main electrical energy source DCGEN, and to electrically power the second winding 62 via the second main electrical converter 72 with the first main electrical energy source 65 and the second main electrical energy source DCGEN.

[0149] The controller 76 thus closes the first main contactor K11, the fourth main contactor K12 and the second main contactor K15. In parallel, the controller 76 opens the third main contactor K13, the sixth contactor K14 and the fifth main contactor KP.

[0150] [Fig. 10] illustrates the starting and electrical generation system 55 of the second variant during a MODPROP electrical energy production mode.

[0151] During this MODPROP electrical energy producing mode, the controller 76 is configured to electrically connect in series the second main electrical converter 72 to the first main electrical converter 68, and to connect them to the first main electrical energy source 65. Similarly, the second main electrical energy source DCGEN can electrically supply the secondary on-board electrical network 301. The controller 76 thus closes the fifth main contactor KP, the second main contactor K15, the sixth contactor K14, or even the third main contactor K13, and opens the fourth main contactor K12 and the first main contactor K11.

[0152] Thus, the secondary on-board electrical network 301 and the first main electrical energy source 65 can be electrically powered by the converters 68, 72 and the second main electrical energy source DCGEN.

[0153] Naturally, the present invention is subject to numerous variations as to its implementation. Although several embodiments have been described, it is understood that it is not conceivable to exhaustively identify all possible modes. It is of course conceivable to replace a means described by an equivalent means without departing from the scope of the present invention defined by the claims.

Claims

Claims

1. Electrical starting and generating system (55) for a combustion main engine (11) of an aircraft (1), the electrical starting and generating system (55) comprising a starter-generator (FSG) provided with a transmission shaft (600), the starter-generator (FSG) being operable in a motor mode (MOT) for setting in motion a main moving assembly (14) of the main engine (11) with the transmission shaft (600) and a generator mode (GEN) for generating electrical energy by having the transmission shaft (600) set in motion by said main moving assembly (14), characterized in that the starter-generator (FSG) comprises a first polyphase winding (61) and a second polyphase winding (62) generating magnetic fields to create respective motor torques jointly setting in motion the transmission shaft (600) in a starting mode of the motor mode (WORD),the electrical starting and generation system (55) comprising a first main electrical energy source (65) connected on command by a first electrical connection (66) at least to a first main electrical converter (68) electrically connected to the first winding (61) and a second main electrical energy source (DCGEN) connected on command by a second electrical connection (71) at least to a second main electrical converter (72) electrically connected to the second winding (62.,

2. Electrical starting and generation system according to claim 1, characterized in that the first main electrical energy source (65) is not regulated in electrical voltage and the second main electrical energy source (DCGEN) is regulated in electrical voltage or the first main electrical energy source (65) and the second main electrical energy source (DCGEN) are regulated to different electrical voltages.

3. An electrical starting and generating system according to any one of claims 1 to 2, characterized in that the first main electrical energy source (65) comprises at least one electric battery or a thermal cell or a supercapacitor.

4. Electrical starting and generation system according to any one of claims 1 to 3, characterized in that the second main electrical energy source (DCGEN) comprises an electrical generator regulated in electrical voltage and configured to be mechanically set in motion by a mechanical system.

5. Electrical starting and generation system according to any one of claims 1 to 4, characterized in that the generator / starter (FSG) comprises an electrical machine having a stator provided with the first winding (61) and the second winding (62) which are polyphase as well as with floating neutral and galvanically isolated from each other, the electrical machine comprising a rotor (64) with buried permanent magnets with variable reluctance integral in rotation with the transmission shaft.

6. Electrical starting and generation system according to any one of claims 1 to 4, characterized in that the generator / starter (FSG) comprises a double electrical machine with separate excitations (110), the double electrical machine with separate excitations (110) comprising a stator (11) provided with the first winding (61) and the second winding (62), the double electrical machine with separate excitations (110) comprising a rotor (112) provided with two rotor windings electrically connected to an electrical brush collector (115).

7. An electrical starting and generating system according to any one of claims 1 to 4, characterized in that the generator / starter (FSG) comprises a magnet starter (120) and an electrical machine (125) operating in generator mode and in motor mode, the magnet starter (120) being provided with a first stator having the first winding (61) and a first rotor (122) which is mechanically connected to the transmission shaft (600) by a freewheel (123), the electrical machine comprising a second stator (126) provided with the second winding (62) and a second rotor (127) secured to the transmission shaft (600), the electrical machine which may be a separately excited or asynchronous electric machine.

8. Electrical starting and generation system according to any one of claims 1 to 4, characterized in that the generator / starter (FSG) comprises a double asynchronous electrical machine (130) comprising a stator provided with the first winding (61) and the second winding (62).

9. An electrical starting and generating system according to any one of claims 1 to 4, characterized in that the generator / starter (FSG) comprises a separately excited electrical machine comprising a stator having one winding among the first winding (61) and the second winding (62) and an asynchronous electrical machine comprising a stator having the other winding among the first winding (61) and the second winding (62).

10. Electrical starting and generation system according to any one of claims 1 to 9, characterized in that the electrical starting and generation system (55) comprises a manager (75) configured to: - in the starting mode (MODRAP), electrically supply the first winding (61) via the first main electrical converter (68) with at least the first main electrical energy source (65), electrically supply the second winding (62) via the second main electrical converter (72) with at least the second main electrical energy source (DCGEN), - in a standby mode (MODVEIL), supply one of the first winding (61) and second winding (62) with the second main electrical energy source (DCGEN), maintain the charge of the first main electrical energy source (65) via a transverse electrical connection (96) connected to the second electrical connection (71),- in an electrical energy producer mode (MODPROD), electrically connect in parallel the second main electrical converter (72) and the first main electrical converter (68) to electrically supply the first main electrical energy source (65).,

11. An electrical starting and generating system according to claim 10, characterized in that the second electrical connection (71) comprises a main bus (671), and the manager (75) comprises: - a controller (76), - a first main contactor (Kl 1) controlled by the controller (76) and arranged on the first electrical connection (66), - a second main contactor (K15) controlled by the controller (76) and arranged on the second electrical connection (71) between the main bus (671) and the second main electrical converter (72).

12. Electrical starting and generation system according to claim 11, characterized in that the manager (75) comprises: - a third main contactor (K 13) controlled by the controller (76) and arranged between the main bus (671) and a connection (672) configured to be electrically connected to a complementary electrical connection (88) of an additional electrical circuit, - a fourth main contactor (K 12) controlled by the controller (76) and arranged on a transverse electrical connection (96), the transverse electrical connection (96) extends from the second electrical connection (71) to the first electrical connection (66) between the first main contactor (Kl 1) and the first main electrical energy source (65),- a fifth main contactor (KP) controlled by the controller (76) and arranged on an electrical line connecting the first electrical connection (66) and the second electrical connection (71) between on the one hand the second main contactor (K15) and the second main electrical converter (72) and on the other hand between the first main contactor (K1 1) and the first main electrical converter (68).,

13. Aircraft (1) provided with a main combustion engine (11) and at least one additional combustion engine (12) connected to a mechanical system (25) setting in motion at least one rotary wing (5) or a rotor or a propeller, the additional engine (12) being connected to an additional electrical machine (SG) capable of operating in a motor mode (MOT) for setting in motion an additional mobile assembly (140) of the additional engine (12) and a generator mode (GEN) for generating electrical energy by being set in motion by said additional mobile assembly (140), the additional electrical machine (SG) being electrically connected to an additional electrical converter (FSGl) which is connected by an additional electrical connection (98) to an additional electrical energy source (95), characterized in that said aircraft comprises a starting and electrical generation system (55) according to any one of claims 1 to 12 for the main engine (11).

14. Aircraft according to claim 13, characterized in that the mechanical system (25) comprising a power transmission box (26) connected to the main engine (11) and to the additional engine (12), the second main electrical energy source (DCGEN) is set in motion by the power transmission box (26).

15. Method for starting a combustion engine and generating electrical energy with a starting and electrical generation system (55) according to any one of claims 1 to 12, characterized in that the method comprises: - a starting mode (MODRAP) comprising the following steps: electrically supplying (STPA1) the first winding (61) via the first main electrical converter (68) with at least the first main electrical energy source (65), electrically supplying (STPA2) the second winding (62) via the second main electrical converter (72) with at least the second main electrical energy source (DCGEN),- a standby mode (MODVEIL) comprising the following steps: supplying (STPB1) one of the first winding (61) and second winding (62) with the second main electrical energy source (DCGEN) and maintaining (STPB2) the first main electrical energy source (65) under load via a transverse electrical connection (96) connected to the second electrical connection (71), - an electrical energy producer mode (MODPROD) comprising the following steps: electrically connecting (STPC2) in parallel the second main electrical converter (72) and the first main electrical converter (68) and connecting them to the first main electrical energy source (65).,

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