AIRSHIP WITH A DISTRIBUTED ELECTRIC PROPULSION SYSTEM

Description

Technical field

[0001] The present invention relates to an airship with hovering flight capabilities. It relates more particularly to an airship carrying heavy loads. State of the prior art

[0002] Typically, a propulsion system in an aircraft comprises two electrical power generation units and two main electrical buses, each connected to one of the two electrical power generation units. Downstream, the propulsion system comprises a plurality of thrusters, each of the thrusters being connected, in a nominal configuration, to one of the two electrical buses. This is the case, for example, in certain multirotor drones and vertical takeoff aircraft.

[0003] According to a nominal configuration, the right propulsion point of an aircraft is for example electrically connected to a power generation unit located to the right of the aircraft, while the left propulsion point of the aircraft is for example electrically connected to a power generation unit located to the left of the aircraft.

[0004] For redundancy reasons, an electrical reconfiguration step is provided for in the event that one of the two power units develops a fault. For example, a possible electrical reconfiguration is provided to supply the left motor via the right-hand generating unit in the event of a fault in the left-hand generating unit. For this purpose, a backup electrical circuit must be provided, connecting the left motor to the right-hand generating unit. The same applies, of course, between the right motor and the left-hand generating unit.

[0005] Document EP 3 521 172 B1 discloses an electric propulsion system of an aircraft, comprising a first energy store for providing electrical energy and a second energy store for providing electrical energy, and a plurality of electric propulsion units for providing drive power to the aircraft. A power distribution unit is provided for transmitting the electrical energy supplied from the first energy store and the electrical energy supplied from the second energy store to at least one electric propulsion unit. This power distribution unit is also configured to charge the second energy store by using a first portion of the energy for at least one propulsion unit and a second portion of the energy for charging the second energy store.

[0006] The emergency circuits must therefore be electrically decoupled from the electrical connections by the main buses in nominal operation, and must take over from a main bus in the event of failure of an electrical unit. This implies that they have almost the same characteristics as the main buses. In addition to the on-board weight of such emergency circuits, which are not useful nominally, but only in the event of a fault, the control of these circuits requires actuators and effectors which can also be sources of failures.

[0007] One aim of the invention is to overcome this drawback.

[0008] US 2018 / 022461 A1 discloses a hybrid airship using one of two technologies, or both together. The first technology uses a combination of a lifting gas (such as hydrogen or helium) in a central volume or balloon and a multirotor technology for lifting and maneuvering. The second technology equips the airship with an onboard generator to charge the batteries during flight for extended flight operations, with an internal combustion engine (such as a high power-to-weight ratio gas turbine engine) driving the generator. A quadcopter or other multicopter configuration is desirable. Statement of the invention

[0009] One aim of the invention is in particular to remedy all or part of the aforementioned drawbacks.

[0010] According to a first aspect of the invention, there is provided an airship according to the appended claim 1, with hovering flight capabilities, comprising an electric propulsion system comprising: a plurality of electric power generators, a plurality of electric buses and a plurality of electric propulsion points.

[0011] In the propulsion system according to the invention, said plurality of propulsion points comprises propulsion clusters each formed from a plurality of electric propeller thrusters.

[0012] A thruster within each of these propulsion clusters is electrically connected by means of an electrical bus among the plurality of electrical buses to a generator within the plurality of electrical power generators and at least one other thruster within this propulsion cluster is electrically connected by means of another electrical bus among the plurality of electrical buses to another generator within the plurality of electrical power generators.

[0013] In a preferred version of the invention, each propulsion point comprises a propulsion cluster formed from a plurality of electric propeller thrusters and at each propulsion point, a thruster within said propulsion cluster is electrically connected by means of an electrical bus among the plurality of electrical buses to a generator within the plurality of electrical power generators and each other thruster within this propulsion cluster is electrically connected by means of another electrical bus among the plurality of electrical buses to another generator within the plurality of electrical power generators.

[0014] Thus, an electrical decoupling is proposed between a thruster connected to an electric power generator by means of an electric bus and another thruster of the same propulsion point connected to another electric power generator by means of another electric bus.

[0015] Decoupling allows: to avoid the complexity of in-flight network reconfiguration through dynamic reconnection contactors, considering that high-power high-voltage contactor technology is not mature enough to be used in flight, to avoid any possibility of fault propagation after reconfiguration, to provide increased native redundancy without reconfiguration, to reduce development costs (power per string is halved), easier validation (less complexity, as no reconfiguration), reduced power / current of electrical equipment.

[0016] According to one possibility, the electric power generators include turbo-alternators.

[0017] Electric power generators can be of the thermal type.

[0018] In one embodiment, the electrical power generators comprise fuel cells.

[0019] According to the invention, at least one cluster of thrusters is dedicated to cruise propulsion.

[0020] According to the invention, at least one cluster of thrusters is dedicated to producing substantially vertical thrust.

[0021] According to one possibility, at least one cluster of thrusters is dedicated to producing vector thrust.

[0022] According to the invention, possibly in combination with the above possibility, at least one cluster of thrusters is dedicated to producing substantially lateral thrust.

[0023] According to a second aspect of the invention, there is proposed a method of managing, according to the appended claim 5, an electric propulsion system equipping an airship capable of hovering flights according to the first aspect of the invention, or one or more of its improvements, said airship comprising a propulsion management module receiving thrust commands from a propulsion point from a flight control module, said management module being configured to address on the one hand power request instructions to each of the power generators and on the other hand thrust commands to each of the thrusters of said propulsion point.

[0024] Advantageously, the method further comprises a modification of the thrust commands to the thrusters of the propulsion point in the event of detection of a failure of a power generation unit or a thruster. Description of figures

[0025] Other advantages and particularities of the invention will appear on reading the detailed description of implementations and embodiments which are in no way limiting, with regard to the appended drawings which do not represent embodiments of the invention, but which may be useful for understanding certain aspects thereof, and in which: [ Fig. 1 ] schematically represents a perspective view of an airship not representing an embodiment of the invention, from starboard and from its bow, [ Fig.2 ] schematically represents a top view of the airship shown on Figure 1 . [ Fig.3 ] schematically represents a detailed view of systems represented on Figure 2 , [ Fig.4 ] schematically represents a connection diagram of systems shown on Figure 2 . Description of embodiment

[0026] The embodiments described below being in no way limiting, it will be possible in particular to consider variants of the invention comprising only a selection of characteristics described, subsequently isolated from the other characteristics described, if this selection of characteristics falls within the scope defined by the appended claims.

[0027] In the figures, an element appearing in several figures retains the same reference. Aircraft with hovering capabilities

[0028] Aircraft are divided into two main classes based on the means of lift used. Aerostats use static force while aerodynes generate dynamic force to balance their weight; they are often referred to as "lighter" or "heavier" than air.

[0029] The present invention relates to an aircraft with hovering capability.

[0030] An airship is an example of such an aircraft, and contains devices designed to provide lift as well as propulsion systems to give it a certain maneuverability. Airships use a propulsion system to move.

[0031] An aerodyne, that is, a "heavier-than-air" aircraft whose lift is primarily provided by aerodynamic force, may also be an aircraft capable of hovering, but is not part of the claimed invention.

[0032] This is the case, for example, when the lift of the aerodyne is provided by a thrust-vectoring power unit which has the capacity to evolve, during a conversion phase, from a flight configuration in which the thrust is vertical to a flight configuration in which the thrust is horizontal.

[0033] This is also the case when the lift of the aerodyne is provided by a rotary wing.

[0034] Furthermore, some aerodynes have both a fixed wing and a rotary wing and have the capacity to evolve, during a conversion phase, from a fixed wing flight configuration to a rotary wing flight configuration. Propellant

[0035] A thruster according to the invention relates to an electric propeller-driven motor. The motor may of course include other elements, such as a geared motor.

[0036] In the present description, the term propellant refers in particular to static type propulsion devices having a horizontal and / or vertical component. The term propellant also refers to thrust vector propulsion devices, for example by orientation of the outlet flow by means of a steerable nozzle.

[0037] Figure 1 illustrates an airship 1 having a roll axis in a longitudinal direction X, a pitch axis in a transverse direction Y, and a yaw axis in a vertical direction Z, perpendicular to the longitudinal direction and to the transverse direction.

[0038] The airship 1 has two stabilizers at the stern, respectively a starboard stabilizer 2 and a port stabilizer 3, equipped with elevators and a rudder 4 equipped with a rudder.

[0039] The airship 1 also has two lateral fins, respectively a starboard fin 5 and a port fin 6 ( Figure 1 ).

[0040] Airship 1 is equipped with four electrical power generators G1, G2, G3, G4. In the example shown, the power generators are of the turboalternator type, also called turbogenerators. According to a variant, the power generators are electrically connected to fuel cells and / or electric batteries. Still in the example shown, each of the four generators has a power of 1 MW.

[0041] In the example shown, the four generators G1, G2, G3, G4 are located inside the lateral fins 5 and 6. More precisely, the turbogenerators G1 and G2 are located inside the starboard fin 5 while the turbogenerators G3 and G4 are located inside the starboard fin 6.

[0042] Still in the example shown, airship 1 is equipped with 7 propulsion points, respectively PXt, PXb, PY, PZbt, PZbb, PZst, PZsb allowing the aircraft to hover and move.

[0043] The propulsion points PXt and PXb are arranged to generate thrust in the longitudinal direction X towards the bow or stern. The propulsion points PXt and PXb are arranged on the starboard and port sides of airship 1.

[0044] Even more precisely, each of the propulsion points PXt and PXb is a propulsion cluster of 6 electric propeller type propulsion units Xt1, Xt2, Xt3, Xt4, Xt5, Xt6, respectively Xb1, Xb2, Xb3, Xb4, Xb5, Xb6. The propellers of each of the propulsion units of the propulsion points PXt and PXb are for example of the three-blade propeller type.

[0045] These propulsion points thus make it possible to generate axial thrust forward, backward or a yaw moment by differential thrust.

[0046] The propulsion point PY is arranged to generate a thrust in the transverse direction Y towards starboard or port, to generate a moment along the yaw axis. In the example shown, the propulsion point PY is arranged at the bow of the airship 1, on the side of its upper part.

[0047] More precisely, the PY propulsion point is a propulsion cluster of 4 electric propeller-type thrusters Y1, Y2, Y3, Y4. The propellers of each of the thrusters of the PY propulsion point are, for example, three-blade propeller types.

[0048] The PZbt and PZbb propulsion points are arranged to generate thrust in the Z direction, either downward or upward. The PZbt and PZbb propulsion points are located at the bow, on the starboard and port sides of airship 1.

[0049] More precisely, each of the propulsion points PZbt and PZbb is a propulsion cluster of 4 propeller-type electric motor-propeller thrusters Zbt1, Zbt2, Zbt3, Zbt4, respectively Zbb1, Zbb2 Zbb3, Zbb4. The propellers of each of the thrusters of the propulsion points Pzbt and PZbb are, for example, three-blade propeller type.

[0050] The PZst and PZsb propulsion points are arranged to generate thrust in the Z direction, either downward or upward. The PZst and PZsb propulsion points are located at the stern, on the starboard and port sides of airship 1.

[0051] More precisely, each of the propulsion points PZst and PZsb is a propulsion cluster of 4 electric propeller propulsion units Zst1, Zst2, Zst3, Zst4, respectively Zsb1, Zsb2, Zsb3, Zsb4. The propellers of each of the propulsion units of the propulsion points Pzbt and PZbb are, for example, three-blade propeller types.

[0052] The propulsion points PZbt, PZbb, PZst and PZsb thus make it possible to generate a vertical thrust upwards or downwards, or a pitching moment by differential thrust between the front and the rear, or a rolling moment by differential thrust between starboard and port.

[0053] As shown on Figure 2 , Airship 1 is further equipped with 4 electric buses with a power transport capacity of 1 MW, Bus 1, Bus 2, Bus 3, Bus 4.

[0054] Each of the electric buses, respectively Bus 1, Bus 2, Bus 3, Bus 4 is connected to a turbine, respectively G1, G2, G3, G4 by means of systems S1, S2, S3, S4 which will be described below.

[0055] Bus 1 is connected to the powertrain Xt1, Xt3, Xb3, Y4, Zbt1, Zbb1, Zst1, Zsb1.

[0056] Bus 2 is connected to the powertrain Xt4, Xb1, Xb4, Y3, Zbt2, Zbb2, Zst2, Zsb2.

[0057] Bus 3 is connected to the powertrain Xt2, Xt5, Xb5, Y5, Zbt3, Zbb3, Zst3, Zsb3.

[0058] Bus 4 is connected to the power unit Xt6, Xb2, Xb6, Y1, Zbt4, Zbb4, Zst4, Zsb4.

[0059] The systems S1, S2, S3, S4 are now described with reference to Figure 3 .

[0060] The S1 system includes: a turbogenerator G1, a rectifier device R1, connected to the turbogenerator G1, a main power distribution unit Main PDU 1, from English Power Distribution Unit,connected to a Bus 1 bus, a HVBATT1 battery, connected to the Main PDU 1 power distribution unit.

[0061] The Main PDU1 main power unit is also connected to a GPU1 floor power supply (from the English Ground Power Unit ).

[0062] The S2 system includes: a turbogenerator G2, a rectifier device R2, connected to the turbogenerator G2, a main power distribution unit Main PDU 2, connected to a bus Bus 2, a battery HVBATT2, connected to the power distribution unit Main PDU 2.

[0063] The Main PDU2 main power unit is also connected to a GPU2 floor power supply.

[0064] The S1 and S2 systems are installed together in the port fin 5. The S3 system comprises: a turbogenerator G3, a rectifier device R3, connected to the turbogenerator G3, a main power distribution unit Main PDU 3, connected to a bus Bus 3, a battery HVBATT3, connected to the power distribution unit Main PDU 3.

[0065] The Main PDU3 main power unit is also connected to a GPU3 floor power supply.

[0066] The S4 system includes: a G4 turbogenerator, a R4 rectifier device, connected to the G4 turbogenerator, a Main PDU 4 main power distribution unit, connected to a Bus 4 bus, a HVBATT4 battery, connected to the Main PDU 4 power distribution unit.

[0067] The Main PDU4 main power unit is also connected to a GPU4 floor power supply.

[0068] The S3 and S4 systems are installed together in the starboard fin 6.

[0069] As illustrated on Figure 4, The flight control of airship 1 is ensured by a control unit Uc, which receives the pilot's orders, processes them and transmits them to all the propulsion units.

[0070] The propellers are individually equipped with a propeller pitch control unit that manages the thrust delivered. Thus, the pilot's commands are transmitted: to the powertrains Xt1, Xt2, Xt3, Xt4, Xt5, Xt6 of the propulsion point PXt, via the control units UcXt1, UcXt2, UcXt3, UcXt4, UcXt5, UcXt6 respectively, to the powertrains Xb1, Xb2, Xb3, Xb4, Xb5, Xb6 of the propulsion point PXb, via the control units UcXb1, UcXb2, UcXb3, UcXb4, UcXb5, UcXb6 respectively, to the powertrains Y1, Y2, Y3, Y4 of the propulsion point PY via the control units UcY1, UcY2, UcY3, UcY4 respectively, to the powertrains Zbt1, Zbt2, Zbt3, Zbt4 of the propulsion point PZbt via the control units respectively UcZbt1, UcZbt2, UcZbt3, UcZbt4, to the powertrains Zbb1, Zbb2 Zbb3, Zbb4, of the propulsion point PZbb via the control units respectively UcZbb1, UcZbb2, UcZbb3, UcZbb4, to the powertrains Zst1, Zst2, Zst3, Zst4 of the propulsion point PZst via the control units respectively UcZst1, UcZst2, UcZst3, UcZst4, to the powertrains Zsb1, Zsb2, Zsb3,Zsb4 from the propulsion point PZsb via the control units UcZsb1, UcZsb2, UcZsb3, UcZsb4 respectively. ,

[0071] The Uc control unit distributes the driver's demand across all the powertrains. In the event of a malfunction, either of a propulsion chain or a powertrain, it distributes this demand across the remaining functional units.

[0072] Each propulsion chain is controlled by a control unit respectively Up1, Up2, Up3, Up4.

[0073] Each turbogenerator is controlled by a control unit GCU1, GCU2, GCU3, GCU4, from English Generator Control Unit, respectively for generators G1, G2, G3, G4.

[0074] Each battery is controlled by a control unit BMS1, BMS2, BMS3, BMS4, from English Battery Management System, respectively for HVBATT1, HVBATT2, HVBATT3, HVBATT4 batteries.

[0075] The Up1 control unit manages the electrical power available on Bus 1. Depending on the total power of the Xt1, Xt3, Xb3, Y4, Zbt1, Zbb1, Zst1, Zsb1 powertrains supplied by Bus 1, the Up1 unit controls the operating point of the G1 turbogenerator, via the GCU1 controller and manages the charging or discharging of the HVBATT1 battery via the BMS1 controller.

[0076] The Up2 control unit manages the electrical power available on Bus 2. Depending on the total power of the Xt4, Xb1, Xb4, Y3, Zbt2, Zbb2, Zst2, Zsb2 powertrains supplied by Bus 2, the Up2 unit controls the operating point of the G2 turbogenerator, via the GCU2 controller and manages the charging or discharging of the HVBATT2 battery via the BMS2 controller.

[0077] The Up3 control unit manages the electrical power available on Bus 3. Depending on the total power of the Xt2, Xt5, Xb5, Y5, Zbt3, Zbb3, Zst3, Zsb3 powertrains supplied by Bus 3, the Up3 unit controls the operating point of the G3 turbogenerator, via the GCU3 controller and manages the charging or discharging of the HVBATT3 battery via the BMS3 controller.

[0078] The Up4 control unit manages the electrical power available on Bus 4. Depending on the total power of the Xt6, Xb2, Xb6, Y1, Zbt4, Zbb4, Zst4, Zsb4 powertrains supplied by Bus 4, the Up4 unit controls the operating point of the G4 turbogenerator, via the GCU4 controller and manages the charging or discharging of the HVBATT4 battery via the BMS4 controller.

[0079] Thus, it is understood for each of the propulsion points, a thruster of said propulsion point is electrically connected by means of an electrical bus to one of the generators of the plurality of electrical power generators and another thruster of said propulsion point is electrically connected by means of another electrical bus to another generator of the plurality of power generators.

[0080] It is understood that when a turbogenerator stops operating, for each propulsion point which previously had a predetermined thrust, and when said propulsion point comprises 4 thrusters, each of the thrusters being powered independently of the others by 1 turbogenerator, the new thrust of the propulsion point is reduced by only a quarter of the previous thrust. This loss of thrust can possibly be corrected by modifying the thrust of the other 3 thrusters of said propulsion point.

[0081] Thus, in the event of failure of a power generation unit and normal operation of another power generation unit, a control unit can generate instructions to thrusters connected to the normally operating power generation unit and an implementation of the instructions by said thrusters.

[0082] Similarly, if a thruster at a propulsion point stops working, and when said propulsion point has 4 thrusters, each of the thrusters being powered independently of the others by 1 turbogenerator, the new thrust of the propulsion point is only reduced by a quarter of the previous thrust. This loss of thrust can possibly be corrected by modifying the thrust of the other 3 thrusters.

[0083] Thus, in the event of failure of a thruster of a propulsion point and normal operation of another thruster of said propulsion point, a control unit can generate instructions intended for the thrusters of said propulsion point operating normally, and an implementation of the instructions by said thrusters.

[0084] Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention as defined by the appended claims.

[0085] Furthermore, the various features, forms, variations and embodiments of the invention may be combined with each other in various combinations to the extent that they fall within the scope defined by the appended claims, and are not incompatible or mutually exclusive.

Claims

1. A hover-capable airship, comprising an electric propulsion system comprising: - a plurality of electric power generators (G1, G2, G3, G4), - a plurality of electrical buses (Bus 1, Bus 2, Bus 3, Bus 4) and - a plurality of electric propulsion points (PXt, PXb, PY, PZbt, PZbb, PZst, PZsb), characterized in that said plurality of propulsion points comprising at least one propellant bundle formed of a plurality of electric-driven propeller-based thrusters dedicated to exert a longitudinal thrust, at least one propellant bundle formed of a plurality of dedicated electric-driven propeller-based thrusters to exert a vertical thrust and at least one of said longitudinal or vertical propellant bundles being arranged so that each thruster within said propellant bundle is electrically connected by means of an electrical bus (Bus 1, Bus 2, Bus 3, Bus 4) among said plurality of electrical buses to a generator within said plurality of electric power generators and each other thruster within said propellant bundle is electrically connected by means of another electrical bus among said plurality of electrical buses to another generator within said plurality of electric power generators, and in that the plurality of propulsion points further comprises at least one propellant bundle (PY) dedicated to producing a lateral thrust, said propellant bundle (PY) being arranged so that one of its thrusters is electrically connected by means of an electrical bus (Bus 1, Bus 2, Bus 3, Bus 4) among said plurality of electrical buses to a generator within said plurality of electric power generators and each at least one other thruster within said propellant bundle is electrically connected by means of another electrical bus among said plurality of electrical buses to another generator within said plurality of electric power generators.

2. The airship according to the preceding claim, wherein each propulsion point comprises a propellant bundle formed of a plurality of electric propeller thrusters where at each propulsion point, a thruster within said propellant bundle is electrically connected by means of an electrical bus among the plurality of electrical buses to a generator within the plurality of electric power generators and each other thruster within said propellant bundle is electrically connected by means of another electrical bus among said plurality of electrical buses to another generator within said plurality of electric power generators.

3. The airship according to any of the preceding claims, wherein the electric power generators comprise turboalternators.

4. The airship according to any of the preceding claims, wherein the electric power generators comprise fuel cells.

5. A method for managing an electrical propulsion system equipping a hover-capable airship according to any one of the preceding claims, said airship comprising a propulsion management module receiving thrust commands from a propulsion point issued by a flight control module, said management module being configured to send, on the one hand, power request instructions to each of the power generators and, on the other hand, thrust commands to each of the thrusters of said propulsion point.

6. The method according to the preceding claim, further comprising a modification of the thrust commands send to the thrusters of the propulsion point in the event that a failure of a power generation unit or of a thruster is detected.