Control of an electrical system

Abstract

The present invention relates to a method for controlling an electrical system (4) for a turbine engine, the method comprising: generating a first control signal; generating a second control signal; drawing of power by the electrical system (4) from the turbine engine.

Description

[0001] CONTROL OF AN ELECTRICAL SYSTEM

[0002] TECHNICAL FIELD

[0003] This presentation concerns the aeronautical field. More specifically, this presentation concerns the control of an electrical system of a turbomachine.

[0004] STATE OF THE ART

[0005] Some aircraft are equipped with an engine and each of the engine and the aircraft includes electrical loads and / or electrical power sources. An electrical system provides the interface between loads, sources, aircraft and engine, thus promoting electrical exchanges between these different elements. The loads can be powered by mechanical tapping on the engine, and the engine can be assisted by electrical tapping on the sources, whether during start-up or in flight. During engine operation, the power supply requirements of the loads can change, sometimes suddenly. On the other hand, the mechanical tapping on the engine must respect a certain number of constraints to ensure optimization of the latter's operation.

[0006] GENERAL STATEMENT

[0007] An aim of this presentation is to enable an aircraft engine to meet the power requirements of electrical loads while respecting its own operating constraints.

[0008] To this end, according to one aspect of the present disclosure, a method for controlling an electrical system for a turbomachine is proposed, the method comprising: generating a first control signal for a power draw by the electrical system on a first rotating body of the turbomachine; generating a second control signal for a power injection by the electrical system on a second rotating body of the turbomachine, the generation of the second control signal being implemented from the first control signal and a main control signal for a power draw by the electrical system on the turbomachine; drawing power by the electrical system on the turbomachine, this draw being implemented from the main control signal and comprising: drawing power by the electrical system on the first rotating body from the first control signal;and injecting power by the electrical system onto the second rotating body from the second control signal; wherein the first control signal and the second control signal are generated such that the power drawn by the electrical system from the first rotating body is greater than the power drawn by the electrical system from the turbomachine.;

[0009] Advantageously, but optionally, the method may comprise at least one of the following characteristics, taken alone or in any combination:

[0010] - the generation of the first control signal is implemented independently of the main control signal;

[0011] - the generation of the first control signal is implemented from the main control signal;

[0012] - the first control signal is generated so that a level of power draw by the electrical system on the first rotating body is constant during operation of the turbomachine;

[0013] - the first control signal is generated so that a level of power draw by the electrical system on the first rotating body varies during operation of the turbomachine;

[0014] - the method further comprises: generating a third control signal for injecting power by the electrical system into an electrical storage device, the generation of the third control signal being implemented from the main control signal, the first control signal and the second control signal; and injecting power into the electrical storage device from the third control signal;

[0015] - the generation of the first control signal is implemented from information relating to the operation of the turbomachine; and

[0016] - the first rotating body is a low pressure body of the turbomachine and the second rotating body is a high pressure body of the turbomachine.

[0017] According to another aspect of the present disclosure, there is provided an electrical system for a turbomachine, the electrical system comprising: an electrical power supply bus intended to be connected to at least one electrical load and configured to supply power to the load in the form of a continuous signal; a first alternating current generator intended to be connected to a first rotating body of the turbomachine to take power from the first rotating body and transform it into power capable of being transferred to the bus; a second alternating current generator intended to be connected to a second rotating body of the turbomachine to take power from the second rotating body and transform it into power capable of being transferred to the bus; a first converter connecting the first alternating current generator to the bus and configured to regulate the bus voltage from a power supplied by the first alternating current generator;a second converter connecting the second alternating current generator to the bus and configured to regulate the bus voltage from a power supplied by the second alternating current generator; and a control device connected to the converters and configured to control the first converter and the second converter in order to compensate for a change in a bus voltage by implementing a method according to the present disclosure.;

[0018] According to another aspect of the present disclosure, there is provided a turbomachine comprising: an electrical system according to the present disclosure; a first rotating body connected to the first generator; and a second rotating body connected to the second generator.

[0019] DESCRIPTION OF FIGURES

[0020] Other characteristics, aims and advantages will emerge from the following description, which is purely illustrative and not limiting, and which must be read in conjunction with the attached drawings in which:

[0021] Figure 1 illustrates an aircraft schematically.

[0022] Figure 2 is a schematic sectional view of an aircraft propulsion system.

[0023] Figure 3 schematically illustrates an electrical system.

[0024] Figure 4 schematically illustrates a mode of implementation of a method for controlling an electrical system.

[0025] Figure 5 schematically illustrates a mode of implementation of a method for controlling an electrical system.

[0026] Throughout the figures, similar elements have identical references.

[0027] DETAILED DESCRIPTION

[0028] Aircraft

[0029] An aircraft 100 is a device configured to rise and move in the air, and may, for example, be an airplane, civil or military, or even a helicopter. An aircraft 100 comprises an airframe which, in the case of an airplane, is composed of a fuselage, a wing structure comprising two wings, empennages, flight control surfaces and landing gear. The aircraft 100 also comprises a plurality of electrical loads (or receivers) 400. Each electrical load 400 is a device powered by electrical energy and capable of being configured to transform the electrical energy that powers it into another form of energy, such as heat or mechanical energy. Non-limiting examples of electrical loads 400 of the aircraft 100 are: an electric motor, a heating and / or air conditioning system, a compressor, etc.These electrical charges 400 make it possible in particular to ensure a certain number of functionalities, in flight as well as on the ground, such as the pressurization and / or illumination of the cabin of the aircraft 100, the operation of the cockpit, etc.

[0030] To supply these electrical loads 400 with electrical energy, the aircraft 100 comprises a plurality of electrical networks, including at least one direct current network. Each electrical network typically comprises a set of electrical conductors, typically a set of wire(s) or bar(s) and / or an assembly of wire(s) and / or one (or more) printed track(s) and / or some device which is used to conduct electricity. The direct current network only allows the circulation of electrical energy in the form of a continuous signal.

[0031] The electrical energy consumed by the electrical loads 400 can, at least in part, be produced by a propulsion system 1, and more precisely by mechanical extraction from rotating bodies BP, HP of the propulsion system 1.

[0032] Propulsion system

[0033] A propulsion system 1 comprises an engine 2 (or turbomachine) and a nacelle 3, and has a main direction extending along a longitudinal axis XX. The propulsion system 1 is configured to be fixed to the airframe of the aircraft 100, for example under its wings, in the case of an airplane, and this by means of a pylon (or mast). The propulsion system 1 can also be mounted on the wing of the airplane or at the rear of its fuselage, or even be integrated into its fuselage.

[0034] Engine 2 may be a twin-spool, twin-flow, direct-drive turbojet engine, as described below, but may also have a different number of spools and / or flows, and / or be another type of turbojet engine, such as a geared turbojet engine or a turboprop, with or without afterburner, shrouded or unshrouded.

[0035] Unless otherwise specified, the terms “upstream” and “downstream” are used in reference to the overall direction of airflow through the propulsion system 1 in operation. Similarly, an axial direction corresponds to the direction of the longitudinal axis XX and a radial direction is a direction perpendicular to the longitudinal axis XX and intersecting the longitudinal axis XX. Furthermore, an axial plane is a plane containing the longitudinal axis XX and a radial plane is a plane perpendicular to the longitudinal axis XX. A circumference is understood to be a circle belonging to a radial plane and whose center belongs to the longitudinal axis XX. A tangential or circumferential direction is a direction tangent to a circumference: it is perpendicular to the longitudinal axis XX but does not pass through the longitudinal axis XX.Finally, the adjectives "inner" (or "internal") and "outer" (or "external") are used in reference to a radial direction so that the inner part of an element is, in a radial direction, closer to the longitudinal axis XX than the outer part of the same element.

[0036] The engine 2 comprises, from upstream to downstream, a fan 20, a compression section 22, comprising a low pressure compressor 220 and a high pressure compressor 222, a combustion chamber 24 and a turbine section 26 comprising a high pressure turbine 262 and a low pressure turbine 260.

[0037] The compressor section 22 comprises a succession of stages each comprising a wheel of moving blades (rotor) rotating in front of a wheel of fixed blades (stator). The turbine section 26 also comprises a succession of stages each comprising a wheel of fixed blades (stator) behind which a wheel of moving blades (rotor) rotates.

[0038] The fan 20, the rotor portion of the low-pressure compressor 220, and the rotor portion of the low-pressure turbine 260 are connected to each other by a low-pressure shaft 280 extending along the longitudinal axis XX, thus forming a low-pressure body (LP body), which is a first rotating body. The rotor portion of the high-pressure compressor 222 and the rotor portion of the high-pressure turbine 262 are connected to each other by a high-pressure shaft 282 extending along the longitudinal axis XX, thus forming a high-pressure body (HP body) which is a second rotating body. The low-pressure shaft 280 is generally housed, over a section of its length, in the high-pressure shaft 282 and is coaxial with the high-pressure shaft 172.

[0039] The compression section 22, the combustion chamber 24 and the turbine section 26 are surrounded by a motor casing 23, to which the stator parts of the low-pressure compressor 220, the high-pressure compressor 222, the high-pressure turbine 262 and the low-pressure turbine 260 are connected, while the fan 20 is surrounded by a fan casing 25. The motor casing 23 and the fan casing 25 are connected to each other by profiled arms 27 extending radially and forming rectifiers (or OGV for "Outlet Guide Vanes" in English terminology), which are distributed circumferentially all around the longitudinal axis XX. At least some of these arms 27 can be provided structural.The longitudinal axis XX defines the axis of rotation for the fan 20, the rotor parts of the compression section 22 and the rotor parts of the turbine section 26, in other words for the LP body and the HP body, which are each capable of being driven in rotation about the longitudinal axis XX relative to the engine casing 23 and the fan casing 25.

[0040] The nacelle 3 extends radially outside the engine 2, all around the longitudinal axis XX, so as to surround both the fan casing 25 and the engine casing 23, and to define, with a downstream portion of the engine casing 23, a downstream portion of a secondary duct B, the upstream portion of the secondary duct B being defined by the fan casing 25 and an upstream portion of the engine casing 23. The upstream portion of the nacelle 3 further defines an air inlet 29 through which the fan 20 sucks in the air flow circulating through the propulsion system 1. The nacelle 3 is integral with the fan casing 25 and attached and fixed to the aircraft 100 by means of the mast.

[0041] The engine 2 may also comprise at least one accessory gear box, called ÀGB (for “Accessory gear box” in English terminology), typically housed in a cavity provided within the nacelle 3. The accessory gear box comprises a set of rotating elements, or gears, for driving a plurality of shafts in rotation around their own axis, accessories being mounted on these shafts to derive useful power from their rotation. The set of gears is itself driven using a power take-off shaft (or RDS for “Radial Drive Shaft” in English terminology) connecting, possibly via a transfer case, the accessory gear box to at least one of the high-pressure HP body and the low-pressure LP body, typically by being meshed with at least one of the high-pressure shaft 282 and the low-pressure shaft 280.In this regard, the power take-off shaft may extend inside a longitudinal cavity provided within one of the arms 27. In this way, power may be taken from at least one of the high pressure HP body and the low pressure LP body to be delivered to at least one of the accessories via the accessory housing.

[0042] The engine 2 may also comprise a plurality of electrical loads 400, such as a starter, variable geometries or defrosting systems, which must also be supplied with electrical energy. The power supply to at least some of these electrical loads 400 may be in the form of a continuous signal, typically a direct voltage.

[0043] In operation, the fan 20 draws in an air flow, a portion of which, circulating within a primary vein A, is successively compressed within the compression section 22, ignited within the combustion chamber 24 and expanded within the turbine section 26 before being ejected from the propulsion system 1. The primary vein A passes right through the engine casing 23. Another portion of the air flow circulates within the secondary vein B which takes an elongated annular shape surrounding the engine casing 23, the air drawn in by the fan 20 being straightened by the straighteners 27 and then ejected from the propulsion system 1. In this way, the propulsion system 1 generates thrust. This thrust can, for example, be used for the benefit of the aircraft 100 on which the propulsion system 1 is attached and fixed.

[0044] Electrical system

[0045] An electrical system 4 is, moreover, distributed between the propulsion system 1 and the aircraft 100 for supplying electrical energy to the electrical loads 400 of the engine 2 and / or the aircraft 100, typically by means of the direct current network. The electrical system 4 makes it possible in particular to provide the interface between the rotating bodies BP, HP of the engine 2 and the electrical network of the aircraft 100. The electrical system is in particular configured to meet the power requirements of the loads 400 of the aircraft 100 and / or the engine 2 by mechanical tapping on the engine 2, to assist the start-up and / or the in-flight operation of the engine 2 using electrical sources of the aircraft 100 and / or the engine 2, and / or to ensure a distribution of power between the rotating bodies BP, HP of the engine 2. In other words, the engine 2 is electrically hybridized.

[0046] The electrical system 4 comprises an electrical bus 40, or electrical power supply bus 40, connected to at least one electrical load 400 of the aircraft 100 and / or the engine 2, preferably a set of several loads 400 of the aircraft 100 and / or the engine 2, the bus 40 being configured to provide electrical power to the load 400 in the form of a continuous signal in order in particular to meet its power needs. In other words, the bus 40 is configured to allow a flow of electrical energy in the form of a continuous signal. The bus 40 may, for example, comprise a set of electrical conductors, typically a set of wire(s) or bar(s) and / or an assembly of wire(s) and / or one (or more) printed track(s) and / or some device which is used to conduct electricity.

[0047] The electrical system 4 further comprises several electrical converters 410, 420, 430, each connected to a respective electrical source 411, 421, 431, i.e. to an element configured to provide electrical power. The electrical sources 411, 421, 431 may be an alternating current generator 411, 421, and / or a direct current source 431. The alternating current generator 411, 421 and the direct current source 431 may belong to the engine 2, i.e. be controlled at the same time as the engine 2, or even be controlled by the engine 2. In this case, they are electrical sources 411, 421, 431 of the engine 2. Moreover, the direct current source 431 is not necessarily located in the engine 2 and may, for example, be housed in the mast making it possible to fix the engine 2 to the aircraft 100. Alternatively, the direct current source 431 belongs to the aircraft 100, i.e. it is controlled at the same time as the aircraft 100.The electrical system 4 may thus comprise a first converter 410 connected to a first alternating current generator 411, a second converter 420 connected to a second alternating current generator 421 and, optionally, a third converter 430 connected to a direct current source 431. The third converter 430 and the direct current source 431 are optional in the sense that, in certain embodiments, they are absent or, in other embodiments, the direct current source 431 is unavailable. On the other hand, each of the converters 410, 420, 430 is connected to the bus 40. In fact, at least one, if not each, of the converters 410, 420, 430 is configured to regulate the voltage of the bus 40 from, that is to say using, power supplied by the electrical source(s) 411, 421, 431 to which the converters 410, 420, 430 are connected.The number and type of converters 410, 420, 430 and electrical sources 411, 421, 431 is, of course, not limiting.

[0048] The voltage regulation of the bus 40 is critical. Indeed, the temporal evolution of the electrical voltage within the bus 40, during the operation of the electrical system 4, if it can occasionally vary around a given nominal value, must nevertheless remain within the limits of a template, which is the guarantee that all the elements which are connected to the bus 40 operate correctly. The template defines, in fact, the upper and lower limits of voltage excursion, as a function of time, during the operation of the electrical system 4. The template may comprise limits defined for normal and / or abnormal operating conditions, which limits surround, symmetrically or not, a nominal electrical voltage level of the bus 40. In a diagram providing the evolution of the electrical voltage as a function of time, a limit of a template is typically represented as a line, broken or not.Preferably, even if the limit does not define a constant electrical voltage value initially, in particular during the characteristic time of putting into operation (or starting) of the electrical system 4 or during the time of establishing a permanent regime in the event of a power transient, it is common for the limit to then define a constant electrical voltage value, in order to guarantee the stability of operation of the bus 40 and, therefore, of the electrical system 4. Such a template may, for example, be defined in a standard relating to the quality of the electrical system 4 and / or of the direct current network, but also be defined by specifications of an aircraft-type vehicle to which the electrical system 4 is connected, typically the requirements of the manufacturer of the aircraft 100 and / or of the engine 2 within which the electrical system 4 is integrated.

[0049] On the other hand, the voltage regulation of the bus 40 makes it possible to meet the power demands of the loads 400 connected to the bus 40. Typically, when the quantity of power drawn by at least one load 400 on the bus 40 is greater than the quantity of power injected onto the bus 40 by at least one converter 410, 420, 430, the voltage of the bus 40 decreases significantly. Conversely, when the quantity of power injected by at least one converter 410, 420, 430 on the bus 40 is greater than the quantity of power drawn onto the bus 40 by at least one load 400, the voltage of the bus 40 increases. Thus, regulating the voltage of the bus 40 makes it possible, in addition to ensuring the safety of the electrical system 4, to meet the power needs of the loads 400.In other words, each of the converters 410, 420, 430 is configured to continuously adapt the power that it injects or draws from the bus 40, according to the voltage of the bus 40, so as to exactly meet the power requirements of the loads 400 connected to the bus 40.

[0050] This injection or this withdrawal of power on the bus 40 by the converters 410, 420, 430 is notably permitted by their connection with the electrical sources 411, 421, 431. In fact, at least one, if not each, of the alternating current generators 411, 421 is connected to a rotating body BP, HP, of the engine 2 to allow an exchange of mechanical and / or electrical power between the rotating body BP, HP and the alternating current generator 411, 421, preferably to take mechanical power from the rotating body BP, HP and transform it into electrical power, which electrical power is then delivered to the first converter 410 and / or to the second converter 420 to be injected on the bus 40, but also, conversely, to take electrical power from the bus 40 and transform it into mechanical power, which mechanical power is then transmitted to the rotating body BP, HP.Since the power supplied by the alternating current generators 411, 421 is in the form of an alternating signal, each of the first converter 410 and the second converter 420 is configured to transform, reversibly, this alternating signal into a direct current signal suitable for being injected, then circulating, on the bus 40. Similarly, the direct current source 431 can deliver power in the form of a direct current signal to the third converter 430, which will still convert it, also reversibly, to shape it according to the constraints specific to the bus 40, then inject it onto the bus 40.Each, or at least one, of the alternating current generators 411, 421 may, for example, be a wound-rotor synchronous machine, typically comprising three stages, called a VFG (for "Variable Frequency Generator" in English terminology), driven by at least one of the high-pressure shaft 282 and the low-pressure shaft 280 of the motor 2, typically via the accessory box. Other types of electrical machines are conceivable, such as, preferably, permanent-magnet synchronous machines, called PMSM (for "Permanent-Magnet Synchronous Machine Drives" in English terminology) which have the advantage in particular of having a smaller mass, or such as asynchronous machines (or "Induction machine" in English terminology) or variable reluctance machines.Preferably, the first alternating current generator 411 is connected to the HP body, while the second alternating current generator 421 is connected to the BP body. The direct current source 431 may, for its part, be an electrical storage device and comprise a battery, a supercapacitor, a direct current generator and / or a fuel cell. The direct current source 431 makes it possible in particular to relieve the rotating bodies BP, HP, or to take over from them, when, for example, the level of withdrawal required to meet the power needs of the loads 400 is too high, but also makes it possible to absorb certain dynamics, such as sudden variations, in the behavior of the loads 400.

[0051] The electrical system 4 further comprises a control device 412, 422, 432, 4000, connected to at least one, if not each, of the converters 410, 420, 430.

[0052] The control device 412, 422, 432, 4000 comprises a central member 4000 and a plurality of control members 412, 422, 432, each of the control members 412, 422, 432 being connected (or integrated) to one of the converters 410, 420, 430. Alternatively, the control device 412, 422, 432 may comprise only the plurality of control members 412, 422, 432, each of the control members 412, 422, 432 being connected (or integrated) to one of the converters 410, 420, 430.

[0053] The control device 412, 422, 432, 4000 is further advantageously configured to receive a signal V representative of a measurement of a voltage of the bus 40. To do this, the control device 412, 422, 432, 4000 can be connected to the bus 40 or to a voltage sensor connected to the bus 40, and receive the signal V from the bus 40 (or from this sensor). This signal V can be received via a physical or wireless link. This signal V represents in particular the evolution of the power requirements of the loads 400 connected to the bus 40. Typically, when a load 400 suddenly requires to be able to draw a significant amount of power from the bus 40, due to the response time of the electrical system 4 to provide the bus 40 with the power necessary to compensate for the power drawn, the voltage of the bus 40 will suddenly drop, and this drop will be fed back to the control device 412, 422, 432, 4000 via the signal V.In the same way, when a load 400 suddenly sheds a significant amount of power on the bus 40, due to the response time of the electrical system 4 to draw the necessary power from the bus 40 to compensate for this shed, the voltage of the bus 40 will suddenly increase, and this increase will be fed back to the control device 412, 422, 432, 4000 via the signal V. As a result, the signal V is typically a time signal, i.e. providing (or representing) the evolution of the voltage of the bus 40 as a function of time. Many loads 400, in particular so-called “active” loads 400, may exhibit this type of dynamic behavior, which may also vary during the different flight phases.

[0054] The changes in the voltage of the bus 40 are compensated by the action of the converters 410, 420, 430, which action therefore follows the change in the voltage, however sudden and fluctuating it may be. This is why this action is coordinated by the control device 412, 422, 432, 4000 to maintain the voltage of the bus 40 within the limits allowing stable operation of the electrical system 4.

[0055] To do this, each of the converters 410, 420, 430 receives from the control device 412, 422, 432, 4000 a control signal CTRL_1, CTRL_2, CTRL_3 which is specific to it, and from which the converter 410, 420, 430 regulates the voltage of the bus 40. The combination of the voltage regulations of each converter 410, 420, 430 thus makes it possible to continuously monitor the power requirements of the loads 400.

[0056] More precisely, it is the central unit 4000 which is, in particular, configured to receive and then process the signal V. In addition, the central unit 4000 is configured to transmit to each of the control units 412, 422, 432 a control signal CTRL_1, CTRL_2, CTRL_3, which can typically take the form of a control current, for controlling the converters 410, 420, 430. The control is therefore carried out in a centralized manner. Alternatively, when the control device 412, 422, 432 only comprises the control units 412, 422, 432, each of the control units 412, 422, 432 is configured to, in particular, receive and process the signal V, and control the converter 410, 420, 430. In other words, the control is then carried out in a decentralized manner.

[0057] The electrical system 4 further comprises a general controller 7, which may for example be all or part of the system providing the interface between the cockpit of the aircraft 100 and the engine 2 (or FADEC or “Full Authority Digital Engine Control”, in English terminology), typically being the control unit of the engine 2, (or ECU for “Electronic Control Unit” in English terminology), which is integrated into the FADEC. The general controller 7 is connected to the control device 412, 422, 432, 4000, in this case to the central unit 4000, but could alternatively be directly connected to each of the control units 412, 422, 432 when the central unit 4000 is not present. In this case, the functions performed by the central body 4000 are either performed locally in the control bodies 412, 422, 432, or performed by the general controller 7.

[0058] The general controller 7 provides in particular information DAT relating to the operation of the propulsion system 1, an over-extraction instruction GEN and / or a threshold instruction Se to the control device 412, 422, 432, 4000.

[0059] The DAT information relating to the operation of the propulsion system 1 may include the speed of the HP body, the speed of the LP body, the temperature of the exhaust gases, or any other information relating to the operation of the propulsion system 1 and useful for the operation of the electrical system 4, and in particular for the implementation of its control, in that it allows the control device 412, 422, 432, 4000 to adapt the operation of the electrical system 4 by taking into account the DAT information relating to the operation of the propulsion system 1.

[0060] The over-extraction instruction GEN determines the level of power extraction likely to be implemented by the electrical system 4 on at least one of the rotating bodies HP, BP, but can also include which of the rotating bodies HP, BP must be the subject of over-extraction, in particular within the framework of the control method described in more detail below.

[0061] The threshold setpoint Se provides the maximum value of the power that the control device 412, 422, 432, 4000 is authorized to have taken by at least one of the converters 410, 420, 430 from its respective electrical source 411, 421, 423. Typically, the threshold setpoint Se provides a maximum value of power that can be taken from the motor 2 by a converter 410, 420 via an alternating current generator 411, 421, on the rotating body HP, BP to which the alternating current generator 411, 421 is connected.

[0062] The control device 412, 422, 432, 4000 is then configured to control the converters 410, 420, 430 as a function of the information DAT relating to the operation of the propulsion system 1, the over-extraction instruction GEN and / or the threshold instruction Se.

[0063] Control process

[0064] To enable the power requirements of the loads 400 to be met in real time, regardless of the operating phase of the engine 2, while respecting the constraints specific to the engine 2, and in particular to its rotating bodies LP, HP, a method for controlling the electrical system 4 is implemented. This control method aims, in particular, to prevent surge phenomena within the low-pressure compressor 220 and / or the high-pressure compressor 222, when power is taken from the rotating bodies LP, HP. Indeed, taking power from the HP body can cause surges in the high-pressure body 222.The power draw from the LP body makes it possible to limit the risk of pumping on the low pressure compressor 220, but risks causing variations in the speed of the engine 2, and therefore in the thrust of the propulsion system 1, in particular at low speed, at which the fraction of power drawn by the electrical system 4 can be significant compared to the power generated for the thrust. On the other hand, the power injection on the LP body can cause pumping of the low pressure body 220. Therefore, the method for controlling the electrical system, by taking these phenomena into account, makes it possible to obtain gains in terms of dimensioning of the propulsion system 1 and / or fuel consumption of the engine 2.

[0065] The control method allows the electrical system 4 to over-draw power from one of the rotating bodies BP, HP, preferably the BP body, and to reject the excess power drawn from another of the rotating bodies BP, HP, preferably the HP body. By over-extraction, it is understood the extraction of a power greater than the need of the electrical system 4 to regulate the voltage of the bus 40, that is to say greater than the need of the electrical system 4 to respond to the power demand of the loads 400. Of course, the control method provides for being able to exchange the roles between rotating bodies HP, BP during the operation of the engine 2, that is to say that the rotating body HP, BP on which the over-extraction was implemented can become the rotating body HP, BP on which the excess power is rejected while the rotating body HP, BP on which the excess power was rejected can become the rotating body HP, BP on which the over-extraction is implemented.The excess power taken by the electrical system 4 corresponds to the fraction of power taken which is not consumed by the loads 400. More precisely, by over-taking from the LP body and rejecting the excess power to the HP body, the high pressure compressor 222 operates with a power input, which not only has the effect of moving it away from its pumping state, but also of making it operate at a higher speed, thus making it possible to free up more margin on an acceleration transient. In addition, the low pressure compressor 220 is capable of operating with a constant mechanical take-off during the operation of the propulsion system 1, which not only has the effect of stabilizing its speed, and thus the thrust generated by the propulsion system 1, but also of limiting excursions in the field of the low pressure compressor 220.The control method is implemented within the central unit 4000, but this is not, however, limiting since this control method can be implemented within one, if not each, of the control units 412, 422, 432. Where appropriate, the control units 412, 422, 432 are capable of exchanging information between themselves, in the form of wired or remote signals, and / or of receiving information from the bus 40 and / or the general controller 7.

[0066] This control method also allows the electrical system 4 to correct a difference (or error) detected between a reference V_ref, which depends on the voltage gauge of the bus 40, represents the state in which the bus 40 should be for normal operation and can be transmitted by the general controller 7, and a measurement of the voltage of the bus 40, which represents the reality of the needs of the loads 400 as expressed by injection or withdrawal of power on the bus 40. In other words, this control method, by correcting this difference between the reference V_ref and the measurement of the voltage of the bus 40, ensures that the power needs of the loads 400 are satisfied by the voltage regulation of the bus 40.

[0067] More precisely, a voltage signal V representative of a measurement of the voltage of the bus 40 is received. This voltage signal V can then be compared to the reference V_ref. If there is no difference between the reference V_ref and the voltage signal V, it is because the instructions sent to the converters 410, 420, 430 satisfy the power requirements of the loads 400 and therefore do not need to be modified. On the other hand, if a difference is observed, that is to say that the voltage of the bus 40 has undergone a change, it is necessary for the instructions sent to the converters 410, 420, 430 to be adjusted in order to compensate for the change in consumption of the loads 400. To do this, it is necessary to control the electrical sources 411, 421, 431, in order to carry out this voltage regulation.

[0068] This control can, for example, consist of the transmission of a control current, a control power or even a control torque. These control signals CTRL_1, CTRL_2, CTRL_3 will determine the way in which the electrical system 4, and more precisely the electrical sources 411, 421, 431, will have to adapt their operation to carry out this voltage regulation. Where appropriate, it is the controllers 412, 422, 432 of the converters 410, 420, 430 which are intended to receive the control signals CTRL_1, CTRL_2, CTRL_3 in order to be controlled to control the operation of the electrical sources 411, 421, 431, in order to carry out this voltage regulation.

[0069] In this case, an initial control signal I0, easier to manipulate by the control member, whether it is the central member 4000 or the control members 412, 422, 432, can advantageously be generated then processed according to the error detected in the voltage signal V with respect to the reference V_ref. The processing can advantageously be implemented by a proportional-integral type corrector.

[0070] From there, a main IP control signal for drawing power by the electrical system 4 from the electrically hybridized engine 2 is ready to reach the electrical system 4. This main IP control signal is representative of the correction to be made by the electrical system 4 to reduce, or even cancel, the difference between reference V_ref and measured signal V, and thus compensate for the change in the voltage of the bus 40, by drawing power from the engine 2, and more particularly from the rotating bodies HP, BP of the engine 2, via the electrical sources 411, 421 formed by the alternating current generators 411, 421. However, this main IP control signal only sets the general setpoint to be adopted by the electrical system 4, without discriminating the role that each of the members of the electrical system 4, and more precisely the electrical sources 411, 421, 431, will have to play in the voltage regulation of the bus 40.

[0071] On average, the voltage of the bus 40 is regulated by taking power from the motor 2 by the electrical system 4. However, when implementing the control method, the power taken from the motor 2 is the result of an over-taking of power from one of the rotating bodies HP, BP, preferably the BP body, and an injection of power into another of the rotating bodies HP, BP, preferably the HP body, the difference between the power taken from one of the rotating bodies HP, BP, preferably the BP body, and the power injected into another of the rotating bodies HP, BP, preferably the HP body, corresponding to the power to be injected into the bus 40 to regulate its voltage, that is to say to reduce, or even cancel, the difference between reference V_ref and measured signal V, that is to say to the power required by the loads 400 corresponding to the main control signal IP.In other words, the power taken by the electrical system 4 from one of the rotating bodies HP, BP, preferably the BP body, is greater than the power required by the loads 400 and taken from the engine 2.

[0072] However, the main control signal IP determines the power to be injected onto the bus 40 by the electrical system 4. This is why, during the control method, a first control signal CTRL_1 for drawing power by the electrical system 4 from a first rotating body HP, BP, preferably the body BP, of the engine 2 is generated in parallel with a second control signal CTRL_2 for injecting power by the electrical system 4 into a second rotating body HP, BP, preferably the body HP, of the engine 2. The first control signal CTRL_1 and the second control signal CTRL_2 are generated so that the power drawn by the electrical system 4 from the first rotating body HP, BP, via an alternating current generator 411, 421 (i.e., the one connected to the first rotating body HP, BP), is greater than the power drawn by the electrical system 4 from the engine 2, the excess power (i.e., the power supplied by the electrical system 4 to the engine 2) being greater than the power supplied by the electrical system 4 to the engine 2., which corresponds to the portion of the power taken from the first rotating body HP, BP which is not injected onto the bus 40 by the electrical system 4) being injected onto the second rotating body HP, BP, via another alternating current generator 411, 421 (i.e., the one connected to the second rotating body HP, BP).

[0073] The generation of the first control signal CTRL_1 can be implemented independently of the main control signal IP or from the latter.

[0074] In an implementation mode in which the first control signal CTRL_1 is generated independently of the main control signal IP, this generation is advantageously implemented from the over-sampling instruction GEN. From this instruction can be extracted a first intermediate signal 11 which is formatted in order to become the first control signal CTRL_1 determining a control to be implemented by the converter 410, 420 to control its alternating current generator 411, 421 in order to take a predefined level of power from the first rotating body HP, BP. Of course, the control can be implemented so as to determine a predefined level of torque to be taken from the first rotating body HP, BP, depending on the way in which the alternating current generator 411, 421 connected to the first rotating body HP, BP is controlled.Advantageously, this generation is also implemented from the DAT information relating to the operation of the propulsion system 1, in order to take into account the constraints specific to the operation of the engine 2, typically the flight conditions. For example, on takeoff, the level of power taken from the BP body can be reduced. This makes it possible to optimize the control of the electrical system 4 and, therefore, to improve the efficiency of the engine 2.

[0075] In an implementation mode in which the first control signal CTRL_1 is generated from the main control signal IP, the power over-drawn on the first rotating body HP, BP is indexed on the power level actually consumed by the bus 40, which makes it possible to vary it during the operation of the engine 2, within the limit of the operability of the rotating bodies HP, BP requested by the electrical system 4. Thus, the generation of the first intermediate signal 11 is not only implemented from the over-drawing instruction and, possibly, from the information DAT relating to the operation of the propulsion system 1, but also from the main control signal IP.The extraction is typically carried out using a transfer function, for example of order 1, which makes it possible to change the withdrawals and / or injections on the HP, BP rotating bodies in an acceptable manner, in particular in terms of fuel regulation, while providing an over-withdrawal margin and ceiling and floor values, by playing, for example, on the multiplicative coefficients and the coefficients at the origin of the transfer function. It should be noted that, in this mode of implementation, punctually and temporarily the over-withdrawal level may, due to the response time of the electrical system 4, become lower than the needs of the loads 40, which requires power to be taken also from the second HP, BP rotating body.

[0076] The generation of the first control signal CTRL_1 can be implemented so that a level of power and / or torque extraction by the electrical system 4 on the first rotating body HP, BP is constant during operation of the engine 2 or, on the contrary, varies during operation of the engine 2.

[0077] In an implementation mode in which the level of power and / or torque extraction by the electrical system 4 on the first rotating body HP, BP is constant during operation of the engine 2, the over-extraction of power is implemented at a predetermined level, regardless of the power level required to regulate the bus 40 in voltage and / or regardless of the speed of the engine 2. The over-extraction setpoint GEN may, in this case, not vary during operation of the engine 2 and be predefined during the design of the latter so as to guarantee that all the power levels necessary for the regulation of the bus 40 (i.e., at most the sum of all the powers of the loads 400 supplied by the bus 40) can be satisfied by the power extracted from the first rotating body HP, BP.In other words, the first control signal CTRL_1 is generated so that the power injected by the converter 410, 420 of the generator 411, 421 connected to the first rotating body HP, BP is permanently greater than the power passing on the bus 40, whatever the operating point of the engine 2. Therefore, it is, in fact, the converter 410, 420 of the alternating current generator 411, 421 connected to the second rotating body HP, BP which regulates the voltage of the bus 40 by injecting the excess power on the bus onto the second rotating body HP, BP. This mode of implementation is simple and easy to integrate into the control of the electrical system 4. In addition, it offers significant operational safety.

[0078] In an embodiment in which the level of power and / or torque extraction by the electrical system 4 on the first rotating body HP, BP varies during operation of the engine 2, this variation may be linked to the evolution of the over-extraction setpoint GEN during operation of the engine 2, to the taking into account and / or the evolution of the information DAT relating to the operation of the propulsion system 1 and / or to the taking into account of the main control signal IP during the generation of the first control signal CTRL_1, as detailed previously. This embodiment has the advantage of adapting the control of the electrical system 4 to the real needs of the loads 400, and thus of adjusting the over-extraction on the first rotating body HP, BP, which, taking into account the efficiencies inherent in such power exchanges, promotes the efficiency of the engine 2 and, from there, limits its fuel consumption.

[0079] The generation of the second control signal CTRL_2 is implemented from the first control signal CTRL_1 and the main control signal IP. Indeed, the second control signal determines the power not consumed by the electrical system 4 (i.e., injected by the electrical system 4 on the bus 40) which is reinjected onto the second rotating body HP, BP. In this regard, a second intermediate signal I2 is generated by difference between the main control signal IP and the first intermediate signal 11, the second intermediate signal I2 then being formatted to generate the second control signal CTRL_2 intended to control the converter 410, 420 connected to the alternating current generator 411, 421 associated with the second rotating body HP, BP.This difference between the main control signal IP and the first intermediate signal 11 is in fact the exact image of the excess power which will not be consumed by the loads 400 and which it is therefore necessary to inject into the second rotating body HP, BP.

[0080] In one embodiment, a third control signal CTRL_3 for injecting power by the electrical system 4 into the electrical storage device 431 is generated. This embodiment is advantageous when too much excess power should be reinjected into the second rotating body HP, BP, i.e. the overdrafting from the first rotating body HP, BP is too large compared to the power actually required to regulate the voltage of the bus 40. In this case, the excess surplus power is injected into the electrical storage device 431, in electrical form, from the third control signal CTRL_3.

[0081] If necessary, the generation of the third control signal CTRL_3 is implemented from the main control signal IP, the first control signal CTRL_1 and the second control signal CTRL_2. Thus, the second intermediate signal I2 is first processed from the threshold setpoint Se, to generate a second corrected intermediate signal I2* associated with a power lower than that associated with the second intermediate signal I2, because it is capped by the threshold setpoint Se. A third intermediate signal I3 is then generated by the difference between the second intermediate signal I2 and the second corrected intermediate signal I2*, then formatted to generate the third control signal CTRL_3. The third intermediate signal I3 is the exact image of the fraction of the excess power that the second rotating body HP, BP cannot handle by reinjection, and which must therefore be reinjected into the storage device 431.

Claims

CLAIMS 1. Method for controlling an electrical system (4) for a turbomachine (2), the method comprising: generating a first control signal (CTRL_1) for a power draw by the electrical system (4) on a first rotating body (HP, BP) of the turbomachine (2); generating a second control signal (CTRL_2) for a power injection by the electrical system (4) on a second rotating body (HP, BP) of the turbomachine (2), the generation of the second control signal (CTRL_2) being implemented from the first control signal (CTRL_1) and a main signal (IP) for controlling a power draw by the electrical system (4) on the turbomachine (2);the drawing of power by the electrical system (4) on the turbomachine (2), this drawing being implemented from the main control signal (IP) and comprising: the drawing of power by the electrical system (4) on the first rotating body (HP, BP) from the first control signal (CTRL_1); and the injection of power by the electrical system (4) on the second rotating body (HP, BP) from the second control signal (CTRL_2); in which the first control signal (CTRL_1) and the second control signal (CTRL_2) are generated so that the power drawn by the electrical system (4) on the first rotating body (HP, BP) is greater than the power drawn by the electrical system (4) on the turbomachine (2);wherein the first control signal (CTRL_1) is generated so that a level of power draw by the electrical system (4) on the first rotating body (HP, BP) varies during operation of the turbomachine (2).; 2. Method according to claim 1, in which the generation of the first control signal (CTRL_1) is implemented independently of the main control signal (IP).

3. Method according to claim 1, in which the generation of the first control signal (CTRL_1) is implemented from the main control signal (IP).

4. Method according to any one of claims 1 to 3, further comprising: generating a third control signal (CTRL_3) for a power injection by the electrical system (4) on an electrical storage device (431), the generation of the third control signal (CTRL_3) being implemented from the main control signal (IP), the first control signal (CTRL_1) and the second control signal (CTRL_2); and injecting power into the electrical storage device (431) from the third control signal (CTRL_3).

5. Method according to any one of claims 1 to 4, in which the generation of the first control signal (CTRL_1) is implemented from information (DAT) relating to the operation of the turbomachine (2).

6. Method according to any one of claims 1 to 5, in which the first rotating body (HP, BP) is a low pressure body (BP) of the turbomachine (2) and the second rotating body (HP, BP) is a high pressure body (HP) of the turbomachine (2).

7. Electrical system (4) for a turbomachine (2), the electrical system (4) comprising: an electrical power supply bus (40) intended to be connected to at least one electrical load (400) and configured to supply power to the load (400) in the form of a continuous signal; a first alternating current generator (411) intended to be connected to a first rotating body (HP, BP) of the turbomachine (2) to take power from the first rotating body (HP, BP) and transform it into power capable of being transferred to the bus (40); a second alternating current generator (421) intended to be connected to a second rotating body (HP, BP) of the turbomachine (2) to inject power into the second rotating body (HP, BP) from power taken from the bus (40);a first converter (410) connecting the first alternating current generator (411) to the bus (40) and configured to regulate the bus (40) in voltage from a power supplied by the first alternating current generator (411); a second converter (420) connecting the second alternating current generator (421) to the bus (40) and configured to regulate the bus (40) in voltage from a power supplied by the second alternating current generator (421); and a control device (412, 422, 432, 4000) connected to the converters (410, 420) and configured to control the first converter (410) and the second converter (420) in order to compensate for a change in a voltage of the bus (40) by implementing a method according to any one of claims 1 to 6.; 8. Turbomachine (2) comprising: an electrical system (4) according to claim 7; a first rotating body (HP, BP) connected to the first generator (411); and a second rotating body (HP, BP) connected to the second generator (421).

Images