Pump actuators and related pumping systems, aircraft and fuel supply methods

Abstract

The present invention relates to an actuation device (22) for a pump (20) of a fuel pumping system (12) of an engine (18), the actuation device comprising a motor (24), a generator (26), an inverter (28), a switching member (30), and a control member (31). The motor (24) comprises a first rotor (32) and a first stator (34), the first rotor being coupled to the pump (20), the first stator comprising at least one input stator winding (36). The generator (26) comprises a second rotor (38) and a second stator (40), the second rotor being coupled to a drive shaft (37) of the engine (18), the second stator comprising at least one output stator winding (42). The control member (31) is configured to control the switching member to: - if the engine speed is higher than or equal to a predetermined speed, selectively connect each input stator winding (36) to the corresponding output stator winding (42); - otherwise, selectively connect each input stator winding to the corresponding output (44) of the inverter.

Description

Technical Field

[0001] The present invention relates to an actuation device intended to drive at least one pump of a fuel pumping system in a fuel circuit toward a fuel injection device of an engine.

[0002] The present invention also relates to a pumping system, an aircraft carrying such a pumping system, and a method for supplying fuel to such an aircraft.

[0003] This invention is applicable to the aviation field, and particularly relates to fuel supply for aircraft engines. Background Technology

[0004] It is known that at least one pump is used on an aircraft to deliver fuel from the aircraft's fuel tank to the aircraft's engine fuel injection system. Such a pump (typically a positive displacement pump) is usually actuated via the aircraft's hydraulic circuit.

[0005] In the context of electrification of some aircraft actuators, including fuel delivery lines, it has been proposed to drive the previously described pumps using rotary motors. More specifically, it has been proposed to provide a first rotary motor, referred to as a "generator," and a second rotary motor, referred to as a "motor," electrically connected to each other. In this case, the output shaft of the motor is coupled to the pump to drive the pump, and the shaft of the generator is coupled to the shaft of the aircraft engine. The generator and motor are typically three-phase motors, particularly asynchronous motors for the motor and asynchronous or synchronous motors for the generator. In this way, during the operation of the aircraft engine, the generator delivers current, the frequency of which is proportional to the rotational speed (also referred to as "velocity") of the aircraft engine. Thus, the rotational speed at the motor output is proportional to the engine speed (within some slip margin), causing the pump to deliver fuel at a flow rate proportional to the engine speed.

[0006] Nevertheless, this pump actuation device is not entirely satisfactory.

[0007] In practice, to ensure that the engine is properly supplied with fuel regardless of engine speed, the size of the pump driven by this actuator is determined such that, for any given speed, the flow rate supplied by the pump is at least equal to the flow rate required by the engine for said speed. Typically, this size determination involves selecting a pump with an appropriate displacement.

[0008] like Figure 1As shown, curve 2, representing the fuel flow required by the engine as a function of engine speed, is typically a concave increasing curve. In this case, between the lowest speed operating point shown by point 4 (corresponding to the engine fan's rotation phase, or "windmill-like") and the highest speed operating point shown by point 6 (corresponding to the takeoff phase, or "takeoff"), the displacement is applied at the operating point where the ratio between the required fuel flow and the engine speed is the highest.

[0009] When displacement is applied at the lowest operating speed point 4, the fuel flow supplied by the pump (represented by line 8 passing through the lowest operating speed point 4) is always higher than the fuel flow required by the engine. For example, at the highest operating speed point 6, the excess fuel flow is represented by arrow 10. In this case, it is necessary to install a fuel recirculation device.

[0010] During operation, this recirculation unit, typically connected to the output of the engine's gearbox, acquires mechanical energy at that output and dissipates a portion of it as heat. However, since the fuel circuit (including the injection system) is used as a cold source for the oil circuit, this dissipation is detrimental. Any heat dissipation negatively impacts the size of the heat exchanger.

[0011] Therefore, the present invention aims to provide a pump actuation device that, for any given operating point of the engine, results in a smaller difference between the fuel flow rate required at said operating point and the fuel flow rate supplied by the pump, thereby reducing the need for fuel recirculation. Summary of the Invention

[0012] Therefore, the object of the present invention is to provide a fuel-actuated device of the aforementioned type, which includes a motor rotating electric motor, a generator rotating electric motor, an energy inverter, a switching component, and a control component. The rotary motor includes a first rotor and a first stator, the first rotor being mechanically coupled to at least one pump to actuate at least one pump, and the first stator including at least one input stator winding. The generator rotary motor includes a second rotor and a second stator. The second rotor is intended to be mechanically coupled to a shaft forming a drive shaft of the engine. The second stator includes at least one output stator winding, each output stator winding being associated with a corresponding input stator winding of the generator rotary motor. The inverter includes at least one output section, each output section of the inverter being associated with a corresponding input stator winding of the motor rotating electric machine. The control component is configured to receive speed information related to the engine speed and control the switching component to: - If the engine speed is higher than or equal to the predetermined speed, each input stator winding of the motor is selectively connected to the corresponding output stator winding. - Otherwise, each input stator winding of the motor rotating the generator is selectively connected to the corresponding output of the inverter.

[0013] In practice, this actuation device allows the selection of the highest speed operating point, even when the highest ratio between the required fuel flow and engine speed corresponds to the lowest speed operating point, based on the pump size (especially the pump displacement). In this case, the control unit allows two different operating modes depending on its action on the switching component: - For speeds higher than or equal to the predetermined operating point (referred to as the "switching" operating point), the motor rotary motor is connected to the generator rotary motor, so that it is driven at a rotational speed proportional to the engine speed; and - For speeds lower than the speed associated with the switching point, the motor rotary motor is connected to the converter and can be controlled according to control rules suitable for rotating the motor rotary motor, so as to be driven at a rotational speed sufficient to supply fuel to the engine, wherein for each operating point below the switching point, the fuel flow rate is at least equal to the fuel flow rate required at said operating point.

[0014] Specifically, the switching point corresponds to the intersection of the curve representing the fuel flow rate required by the engine as a function of engine speed and the line representing the linear function of the fuel flow delivered by the pump and engine speed due to dimensional adjustments.

[0015] As described above, due to the actuation device according to the present invention, the difference between the fuel flow rate required for any given operating point of the aircraft engine and the fuel flow rate supplied by the pump is much smaller than the difference between the fuel flow rate required for any given operating point of the aircraft engine and the fuel flow rate supplied by the pump obtained by a known actuation device. Therefore, the fuel recirculation requirement is significantly reduced.

[0016] According to other advantageous aspects of the invention, the actuating device includes one or more of the following features, which can be considered individually or in combination in all technically possible ways: - The rotating motor is an asynchronous motor, and / or the rotating motor of the generator is a permanent magnet synchronous motor or an asynchronous motor; - The control unit is configured to control the operation of the inverter according to a predetermined control rule, which depends on the speed of the motor; - The control unit is configured to receive speed information related to the current drive speed of each pump being driven, and the control unit is also configured to: when the engine speed is lower than a predetermined speed: • Compare the current driving speed with the predetermined target driving speed; • Control the inverter to supply a voltage to each corresponding input stator winding, the frequency and amplitude of which depend on the difference between the current drive speed and the target drive speed; - The target driving speed follows a predetermined time curve or is a predetermined constant; - The control unit is configured to control the inverter according to the so-called "V / f" control rule; - The control unit is configured to control the inverter so that the frequency of the power supply voltage supplied by the inverter to the motor rotates has a predetermined evolution over time.

[0017] Furthermore, the object of the present invention is to provide a fuel pumping system comprising at least one pump and an actuation device as defined above, wherein a first rotor of a motor rotating an electric motor is mechanically coupled to each pump to actuate each pump.

[0018] Furthermore, the object of the present invention is to provide an aircraft that carries the fuel pumping system as defined above, wherein each pump is disposed between the fuel circuit of the aircraft and the fuel injection component of the aircraft's engine, and the second rotor of the generator rotary motor is mechanically connected to the shaft of the engine.

[0019] Another object of the present invention is to provide a method for supplying fuel to the engine of an aircraft as defined above, the method comprising: - If the engine speed is higher than or equal to the predetermined speed, each input stator winding of the motor is selectively connected to the corresponding output stator winding. - Otherwise, each input stator winding of the motor rotating the generator is selectively connected to the corresponding output of the inverter. Attached Figure Description

[0020] The invention will be better understood by means of the following description, given only as a non-limiting example and with reference to the accompanying drawings, in which: Figure 1 It is the engine's fuel demand, which is a function of the rotational speed of the engine's high-pressure shaft.

[0021] Figure 2 This is a schematic diagram of the pumping system according to the present invention.

[0022] Figure 3 and Figure 1 Similarly, it also shows the work of... Figure 2The evolution of the fuel flow rate supplied by the pumping system. Detailed Implementation

[0023] Figure 2 A fuel pumping system 12 according to the present invention is shown, particularly a fuel pumping system for an aircraft engine.

[0024] The pumping system 12 is designed to deliver fuel from the fuel tank 14 of the aircraft (not shown) to the fuel injection device 16 of the aircraft's engine 18.

[0025] More specifically, the pumping system 12 includes at least one pump 20 and an actuator 22, the pump being arranged between the fuel tank 14 and the injection device 16, and the actuator being used to drive the pump 20 or each pump.

[0026] The actuation device 22 includes a motor rotating motor 24 (referred to as "motor"), a generator rotating motor 26 (referred to as "generator"), an inverter 28, a switching component 30, and a control component 31.

[0027] Motor 24 is configured to receive electrical energy from generator 26 or inverter 28 and convert the received electrical energy into mechanical energy intended to actuate pump 20 or each pump.

[0028] The motor 24 includes a rotor 32 (referred to as the "first rotor") and a stator 34 (referred to as the "first stator").

[0029] The first rotor 32 is mechanically connected to at least one pump 20 to actuate at least one pump.

[0030] The first stator 34 includes at least one winding 36 referred to as an “input stator winding”, such as three input stator windings 36.

[0031] As will be described later, each input stator winding 36 of the motor 24 is associated with both the output stator winding 42 of the generator 26 and the output section 44 of the inverter 28.

[0032] The generator 26 is configured to extract mechanical energy from the shaft 37 (so-called "drive shaft") of the engine 18 and convert the extracted mechanical energy into electrical energy. For example, the drive shaft 37 is the low-pressure shaft of the engine 18.

[0033] The generator 26 includes a rotor 38 (referred to as the "second rotor") and a stator 40 (referred to as the "second stator").

[0034] The second rotor 38 is mechanically connected to the drive shaft of the motor via any suitable transmission mechanism (e.g., a reduction gear).

[0035] The second stator 40 includes at least one winding 42 referred to as an "output stator winding," for example, three output stator windings 42. Each output stator winding 42 is associated with a corresponding input stator winding 36.

[0036] Motor 24 is an asynchronous motor. Furthermore, preferably, generator 26 is a permanent magnet synchronous motor or an asynchronous motor.

[0037] Inverter 28 includes multiple outputs 44, each associated with a corresponding input stator winding 36 of motor 24. Additionally, inverter 28 is connected at its input to an onboard electrical power source 46.

[0038] Inverter 28 is configured to obtain electrical energy from onboard power supply 46 and supply current with predetermined characteristics from the obtained electrical energy at each output 44 of the inverter.

[0039] Specifically, the onboard power supply 44 is either the aircraft's DC voltage bus or the aircraft's AC network connected to the rectifier. A three-phase voltage inverter is then added, whose power switch is controlled to start the machine and then drive it at a predetermined fixed speed.

[0040] The operation of inverter 28 (especially the control rules of the inverter) will be explained in more detail later.

[0041] The switching member 30 is connected at the input to each output stator winding 42 of the generator 26 and each output section 44 of the inverter 28. Furthermore, the switching member 30 is connected at the output to each input stator winding 36 of the motor 24.

[0042] The switching unit 30 is configured to selectively connect each input stator winding 36 of the motor 24 to the corresponding output stator winding 42 or the corresponding output section 44 of the inverter 28 according to the control signal received from the control unit 31.

[0043] For example, the switching component 30 is formed by a relay, contactor or electronic switch.

[0044] As described above, the control member 31 is configured to control the switching of the switching member 30.

[0045] More specifically, control component 31 is configured to receive speed information related to the speed of engine 18 and to send control signals based on that speed information. For example, this speed information is the rotational speed of the shaft of engine 18 (specifically drive shaft 37). According to another example, the engine speed information is information indicating the flight stage of the aircraft or the aircraft's piloting commands.

[0046] The control member 31 is also configured to control the switching member 30 such that when the speed information indicates that the engine 18 is at a speed exceeding a predetermined switching speed, each input stator winding 36 of the motor 24 is connected to the corresponding output stator winding 42 of the generator 26.

[0047] Furthermore, the control unit 31 is configured to control the switching unit 30 such that when the speed information indicates that the engine 18 is at a speed lower than the predetermined switching speed, each input stator winding 36 of the motor 24 is connected to the corresponding output section 44 of the inverter 28.

[0048] Now refer to Figure 3 Describe the switching method.

[0049] In Figure 3 In the diagram, curve 52 represents the evolution of the fuel flow required by engine 18 as a function of engine speed. Curve 52 extends from point 54 to point 56, where point 54 is the lowest operating speed point of engine 18 and point 56 is the highest operating speed point.

[0050] Point 54 is associated with an operating point where the required fuel flow rate to engine speed ratio is higher than that associated with point 56.

[0051] As mentioned earlier, this curve typically increases with speed and is generally concave.

[0052] Line 58, passing through the minimum speed operating point 54, represents the fuel flow rate of pump 20 under the following conditions: - When each input stator winding 36 of the motor 24 is connected to the corresponding output stator winding 42 of the generator 26; and - When the displacement of pump 20 is selected such that the fuel flow rate supplied by pump 20 at point 54 is at least equal to the fuel flow rate required by the engine.

[0053] Furthermore, line 60 passing through the highest speed operating point 56 indicates the fuel flow rate of pump 20 under the following conditions: - When each input stator winding 36 of the motor 24 is connected to the corresponding output stator winding 42 of the generator 26; and - When the displacement of pump 20 is selected such that the fuel flow rate supplied by pump 20 at point 56 is at least equal to the fuel flow rate required by engine 18.

[0054] like Figure 3As shown, for any speed higher than the speed associated with the intersection point 62 of straight line 60 and curve 52, pump 20 is capable of supplying fuel to engine 18 at a flow rate higher than or equal to the flow rate required by the engine. The intersection point forms a switching point, and the associated speed is referred to as the "switching speed".

[0055] As can be seen from the figure, apart from the switching speed, the demand for fuel recirculation when pump 20 is driven to supply fuel to injection device 16 at a flow rate of line 60 (arrow 64) is significantly lower than the demand for fuel recirculation when pump 20 is driven to supply fuel to injection device 16 at a flow rate of line 58 (arrow 66).

[0056] Alternatively, the switching speed is a predetermined speed that differs from the speed corresponding to the previously described operating point 62.

[0057] Advantageously, the control member 31 is configured to control the operation of the inverter 28. Specifically, the control member 31 is configured to control the operation of the inverter 28 according to a predetermined control rule when the speed of the motor 18 is lower than the switching speed (i.e., when the control member 31 controls the switching member 30 to connect each input stator winding 36 of the motor 24 to the corresponding output section 44 of the inverter 28).

[0058] More specifically, in this case, the control element 31 is configured to control the operation of the inverter 28 so that the inverter 28 delivers current at the inverter output 44 intended to drive the motor 24 at a target rotational speed.

[0059] The target rotational speed causes the pump 20 to deliver fuel to the engine 18 via the motor 24 at a flow rate at least equal to that required by the engine 18 (for the speed in question).

[0060] Therefore, according to the first variant, the control element 31 is configured to control the operation of the inverter 28 according to the so-called "speed regulation" mode.

[0061] More specifically, in the speed regulation mode, the control member 31 is configured to receive speed information related to the speed at which the pump 20 or each pump is driven, such as information related to the rotational speed of the first rotor 32 of the motor 24, via appropriate sensors (not shown).

[0062] Furthermore, the control element 31 is configured to compare the measured drive speed (i.e., the current drive speed) with the target drive speed of the pump 20. For example, this target drive speed may follow a predetermined time curve or be a predetermined constant.

[0063] The predetermined time curve and / or predetermined constant depends on the current speed of engine 18.

[0064] The controller 31 is also configured to control the inverter 28 based on the difference between the measured drive speed and the target drive speed of the pump 20, in order to reduce the difference. Therefore, this control consists of closed-loop regulation.

[0065] Specifically, the control unit 31 is configured to control the frequency of the power supply voltage applied to the motor 24 by the inverter 28 based on the difference between the measured drive speed and the target drive speed of the pump 20. Furthermore, the control unit 31 is configured to control the inverter 28 to apply the amplitude of the power supply voltage to the motor 24 according to a known so-called "V / f" control rule, in order to ensure a constant magnetic flux at the air gap of the motor 24.

[0066] Advantageously, the control element 31 is also configured to control the inverter 28 to compensate for the stator resistance effect at low speeds of the input stator winding 36, thereby improving the performance of the motor 24.

[0067] According to the second variant, in the absence of a rotational speed sensor for the first rotor 32, the control unit 31 is configured to control the inverter 28 according to a so-called "fixed speed" mode.

[0068] More specifically, in fixed-speed mode, control unit 31 is configured to control inverter 28 to supply power voltage of a predetermined frequency to motor 24. Furthermore, control unit 31 is configured to control inverter 28 to apply the amplitude of the power voltage to motor 24 according to a known so-called "V / f" control rule, thereby ensuring a constant magnetic flux at the air gap of motor 24.

[0069] For example, the control element 31 is configured such that the predetermined frequency of the power supply voltage of the motor 24 evolves over time in a predetermined manner.

[0070] Advantageously, the control element 31 is also configured to control the inverter 28 to compensate for the stator resistance effect at low speeds of the input stator winding 36, thereby improving the performance of the motor 24.

[0071] Therefore, as can be seen from the entire text, in each of the modes described above, the control element 31 is configured to control the inverter 28 using a predetermined control rule, which depends on the current speed of the engine 18.

[0072] The operation of pumping system 12 will now be described.

[0073] During the operation of engine 18, control component 31 receives speed information related to the speed of engine 18.

[0074] If the speed information indicates that the engine 18 is at a speed exceeding the predetermined switching speed, the control member 31 controls the switching member 30 to connect each input stator winding 36 of the motor 24 to the corresponding output stator winding 42 of the generator 26.

[0075] In this case, by adjusting the size of the pump, the pump 20, driven at a speed proportional to the engine speed, delivers fuel to the engine 18 at a flow rate at least equal to the fuel flow rate required by the engine.

[0076] Furthermore, if the speed information indicates that the engine 18 is at a speed lower than the predetermined switching speed, the control member 31 controls the switching member 30 to connect each input stator winding 36 of the motor 24 to the corresponding output section 44 of the inverter 28.

[0077] In the latter case, the control unit 31 also controls the inverter 28 to drive the pump 20 at a target rotational speed corresponding to the speed of the engine, so that the pump 20 delivers fuel to the engine 18 at a flow rate at least equal to the fuel flow rate required by the engine 18.

Claims

1. An actuation device (22) intended to drive at least one pump (20) of a fuel pumping system (12) for pumping fuel from a fuel circuit (14) toward a fuel injection device (16) of an engine (18), the actuation device (22) comprising a motor rotating motor (24), a generator rotating motor (26), an energy inverter (28), a switching component (30), and a control component (31). The motor rotary motor (24) includes a first rotor (32) and a first stator (34), the first rotor being mechanically coupled to the at least one pump (20) to actuate the at least one pump, and the first stator including at least one input stator winding (36). The generator rotary motor (26) includes a second rotor (38) and a second stator (40), the second rotor being mechanically coupled to a shaft (37) forming a drive shaft of the engine (18), and the second stator including at least one output stator winding (42), each output stator winding (42) being associated with a corresponding input stator winding (36) of the motor rotary motor (24). The power inverter (28) includes at least one output section (44), each output section of the power inverter (28) being associated with a corresponding input stator winding (36) of the motor rotating machine (24). The control member (31) is configured to receive speed information related to the speed of the engine (18) and control the switching member (30) to: - If the speed of the engine (18) is higher than or equal to the predetermined speed, each input stator winding (36) of the motor rotary motor (24) is selectively connected to the corresponding output stator winding (42). - Otherwise, each input stator winding of the motor rotating machine is selectively connected to the corresponding output (44) of the power inverter (28).

2. The actuation device (22) according to claim 1, wherein, The motor rotary motor (24) is an asynchronous motor, and / or the generator rotary motor (26) is a permanent magnet synchronous motor or an asynchronous motor.

3. The actuating device (22) according to claim 1 or 2, wherein, The control component (31) is configured to control the operation of the power inverter (28) according to a predetermined control rule, which depends on the speed of the engine (18).

4. The actuation device (22) according to claim 3, wherein, The control member (31) is configured to receive speed information related to the current drive speed at which each pump (20) is driven, and the control member (31) is also configured to: when the speed of the engine (18) is lower than the predetermined speed: - Compare the current driving speed with the predetermined target driving speed; - Control the power inverter (28) to supply a voltage to each corresponding input stator winding (36) such that the frequency and amplitude of the voltage depend on the difference between the current drive speed and the target drive speed.

5. The actuation device (22) according to claim 4, wherein, The target driving speed follows a predetermined time curve or is a predetermined constant.

6. The actuation device (22) according to claim 4, wherein, The control component (31) is configured to control the power inverter (28) according to the "V / f" control rule.

7. The actuation device (22) according to claim 3, wherein, The control component (31) is configured to control the power inverter (28) such that the frequency of the power supply voltage supplied by the power inverter (28) to the motor rotating motor (24) has a predetermined evolution over time.

8. A fuel pumping system (12) comprising at least one pump (20) and an actuation device according to any one of claims 1 to 7, wherein a first rotor (32) of the motor rotating electric motor (24) is mechanically coupled to each pump (20) to actuate each pump.

9. An aircraft carrying a fuel pumping system (12) according to claim 8, wherein each pump (20) is disposed between the fuel circuit (14) of the aircraft and the fuel injection device (16) of the engine (18) of the aircraft, and the second rotor (38) of the generator rotary motor (26) is mechanically coupled to the shaft (37) of the engine (18).

10. A method of supplying fuel to an engine (18) of an aircraft according to claim 9, the method of supplying fuel comprising: - If the speed of the engine (18) is higher than or equal to the predetermined speed, each input stator winding (36) of the motor rotary motor (24) is selectively connected to the corresponding output stator winding (42). - Otherwise, each input stator winding of the motor rotating machine is selectively connected to the corresponding output (44) of the power inverter (28).

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