Centralized control method for paralleling sources

Abstract

Control system for controlling electrical sources connected in parallel on a distribution bus (30), the distribution bus (30) having a bus voltage (Vdc) to be regulated around a reference voltage (Vref), the control system comprising: a central regulator (40) configured to generate, at a center frequency (Fc), a total setpoint (Ptot) from a measurement (Vmes) of the bus voltage (Vdc), and from the reference voltage (Vref), and local setpoints (P) respectively associated with the electrical sources from the total setpoint (Ptot) and a power distribution setpoint between the electrical sources;local controllers (311, 321, 331) in communication with the central regulator (40), each local controller (311, 321, 331) being associated with an electrical source, and configured to: generate a first threshold value (V1) lower than the reference voltage (Vref) and a second threshold value (V2) higher than the reference voltage; generate at a local frequency (Fl) a minimum setpoint (P1) from the first threshold value (V1) and the measurement (Vmes); generate at the local frequency (Fl) a maximum setpoint (P2), from the second threshold value (V2) and the measurement (Vmes), the local frequency (Fl) being higher than the central frequency (Fc); generate an output setpoint (Pc) from one of the local setpoints (P), such that the output setpoint (Pc) is equal to: the local setpoint (P) if the local setpoint (P) is greater than the minimum setpoint (P1) and less than the maximum setpoint (P2);The minimum setpoint (P1) if the local setpoint (P) is less than the minimum setpoint (P1); the maximum setpoint (P2) if the local setpoint (P) is greater than the maximum setpoint (P2). Control the associated power source using the output setpoint (Pc). Figure for the abbreviation: Fig. 5;

Description

Title of the invention: Centralized control method for paralleling sources. Technical field

[0001] This disclosure relates to the general field of electrical source control systems, and in particular to voltage regulation when electrical sources are put in parallel by a centralized controller. STATE OF THE ART

[0002] Climate change is a major concern for many legislative and regulatory bodies worldwide. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new types of aircraft and those currently in operation, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively working for several years now to contribute to the fight against climate change.

[0003] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into account the factors impacting all phases of design and development in order to obtain aeronautical components and products that are less energy-intensive, more environmentally friendly, and whose integration and use in civil aviation have moderate environmental impacts, with the aim of improving the energy efficiency of aircraft.

[0004] Consequently, the Applicant is constantly working to reduce its climate impact by employing sustainable development methods and minimizing greenhouse gas emissions. This sustained research and development work focuses in particular on new generations of aircraft engines and the development of the use of electric technologies for propulsion.

[0005] An aircraft generally comprises an electrical network powered by various sources and is propelled by a turbomachine. In order to improve the aircraft's energy efficiency, it is possible to implement internal hybridization of the turbomachine. This involves adding a hybrid electrical system that forms an interface between the rotating mechanical shafts of the turbomachine and the aircraft's electrical network. The hybrid electrical system aims to assist the turbomachine in order to optimize its operation by providing assistance electrical or by drawing power. It must control the sharing of power between the high-pressure and low-pressure mechanical shafts of the turbomachine, and in particular limit the power drawn, ensuring that all sources provide a good supply to the aircraft's electrical network.

[0006] A first proposed solution is an electrical system with a decentralized controller. In this case, the low-pressure and high-pressure shafts are controlled independently and their voltage is regulated by controllers with non-zero steady-state error, for example, by droop control. However, proper power distribution depends heavily on the accuracy of the voltage measurements and the load level. Thus, the bus voltage that one seeks to regulate is strongly affected by local measurement errors.

[0007] Beyond parallelizing the different power sources, it is therefore advantageous to have information exchange. A second proposed solution is an architecture with a central regulator, which performs voltage regulation of the power grid and distributes power commands to the local controllers. This second solution is more robust to the loss of a source, but requires high-speed communication, typically above 10 kHz, between the different power sources and the central regulator.

[0008] However, since the various electrical sources are distributed within the aircraft with large distances from the central regulator and severe electromagnetic environments, rapid communication between the local controllers and the central regulator is difficult, as the information transmission time of the communication buses is dependent on the distance. Description of the invention

[0009] One purpose of the present disclosure is to control several electrical sources in parallel, without communication between the electrical sources, and not requiring rapid communication between the central regulator and the local controllers.

[0010] This goal is achieved by a control system for controlling electrical sources connected in parallel on a distribution bus, the distribution bus having a bus voltage to be regulated around a reference voltage, the control system comprising: - a central regulator configured to generate, at a center frequency, a total setpoint from a measurement of the bus voltage, and from the reference voltage, and local setpoints respectively associated with the electrical sources from the total setpoint and a setpoint for power distribution between the electrical sources; - local controllers communicating with the central regulator, each local controller being associated with a power source and configured to: • generate a first threshold value lower than the reference voltage and a second threshold value higher than the reference voltage; • generate a minimum setpoint at a local frequency from the first threshold value and the measurement; • generate a maximum setpoint at the local frequency, from the second threshold value and the measurement, the local frequency being greater than the center frequency; • generate an output setpoint from one of the local setpoints, such that the output setpoint is equal to: - the local setpoint if the local setpoint is higher than the minimum setpoint and lower than the maximum setpoint; - the minimum setpoint if the local setpoint is lower than the minimum setpoint; - the maximum setpoint if the local setpoint is higher than the maximum setpoint; - control the associated power source using the output setpoint.

[0011] The proposed control system comprises an architecture that transmits setpoints centrally to local controllers. Such an architecture is, as is known, more robust to the loss of one of the power sources than a completely decentralized architecture, when the loss is detected, in which the sources are controlled independently.

[0012] The central regulator allows the power to be drawn to be shared directly by transmitting respective setpoints to each power source at the central frequency, which is lower than the local frequency. The proposed solution thus eliminates the need for rapid communication between the central regulator and the local controllers, as the setpoint adjustment for each source is implemented locally. Indeed, each local controller can perform efficient high-frequency regulation by thresholding the received setpoint at a low frequency when it exceeds maximum and minimum values. Local regulation is faster than centralized regulation. The control of the power sources thus adapts more quickly to sudden variations, while remaining bounded. In the event of a high power surge on the distribution bus, the voltage excursion on the distribution bus will be limited.This improves the stability of the electrical grid. Local controllers do not communicate with each other; the local setpoint is used to distribute the power to be supplied among the different sources. It is therefore possible to slow down the... The central regulator's bandwidth is reduced, and the central frequency and the information transmission speed of the communication buses between the central regulator and the local controllers are also reduced. The proposed control system therefore allows for bus voltage regulation at the interconnection of multiple sources, preserving the stability of the electrical grid within a centralized architecture that is more robust to the loss of electrical sources.

[0013] The proposed control system is suitable for the context of a hybrid turbomachine electrical system, as it allows for the satisfaction of power sharing control criteria between electrical sources. Adjusting the maximum and minimum values ​​specific to each source allows for prioritizing the sources, for example, drawing power first from certain sources, depending on the flight or aircraft startup phases, for instance.

[0014] The invention is advantageously complemented by the following features, taken individually or in any of their technically possible combinations: - each local controller includes • a first control loop configured to take as input the first threshold value and the measurement, and to provide as output the minimum setpoint, and • a second control loop configured to take as input the second threshold value and the measurement and provide as output the maximum setpoint; - the first control loop and the second control loop are zero static error control loops, for example proportional-integral control loops; - the first regulation loop and / or the second regulation loop uses an integral anti-saturation corrective term; - Each local controller includes: • a maximum selector configured to provide a maximum output between the output of the first control loop and the local setpoint, and • a minimum selector configured to provide a minimum output between the output of the second control loop and the local setpoint,

[0015] the output setpoint being generated by each local controller via the maximum selector and the minimum selector; - each local controller is configured to dynamically generate at least one of the first threshold value and the second threshold value according to a setpoint from a central computer; - each local controller is configured to reduce the first threshold value if the output setpoint is equal to the minimum setpoint for a period exceeding a limit time, and / or to increase the second threshold value if the output setpoint is equal to the maximum setpoint for a period exceeding the limit time; - at least one local controller is configured to increase the first threshold value and / or decrease the second threshold value, in case of a communication breakdown between the local controller and the central regulator; - the central regulator includes a central regulation loop with zero static error, in particular a proportional-integral regulation loop, taking as input the measurement of the bus voltage and the reference voltage, and generating at output the total setpoint; - the central control loop uses an integral anti-saturation correction term, the correction term being representative of the difference between the total setpoint and the local setpoints; - the local frequency is at least five times higher than the central frequency;

[0016] According to another aspect, an electrical system comprising • a distribution bus to which at least one electrical load is intended to be connected, • electrical sources, intended to supply current to the distribution bus, and • a control system as described above,

[0017] in which the local controllers are respectively associated with the electrical sources, the current supplied by each electrical source depending on the output setpoint generated by the associated local controller.

[0018] According to another aspect, a bus voltage regulation method is proposed for a distribution bus connecting electrical sources, implemented by a central regulator and by local controllers associated respectively with the electrical sources, the regulation method comprising the steps of: • generation, by the central regulator, of a total setpoint from a measurement of the bus voltage and a reference voltage, and of local setpoints respectively transmitted to the local controllers, from the total setpoint and a power distribution setpoint, the total setpoint and the local setpoints being generated at a central frequency, • generation, by each local controller, of a minimum setpoint based on a first threshold value lower than the reference voltage, and of a maximum setpoint based on a second threshold value higher than the reference voltage, at a local frequency, the local frequency being higher than the center frequency, • generation, by each local controller, of an output setpoint from a received local setpoint, the output setpoint being equal to: • to the local setpoint, if the local setpoint is higher than the minimum setpoint and lower than the maximum setpoint; • to the minimum setpoint if the local setpoint is lower than the minimum setpoint; • and to the maximum setpoint if the local setpoint is higher than the maximum setpoint, • control, by each local controller, of the associated power source using the output setpoint.

[0019] Prioritization between electrical sources can be done dynamically (separation, withdrawal limits) by changing the threshold values ​​used in the local regulation loops. DESCRIPTION OF THE FIGURES

[0020] Other features, objectives and advantages of the invention will become apparent from the following description, which is purely illustrative and not limiting, and which should be read in conjunction with the accompanying drawings on which:

[0021] Fig. 1 schematically illustrates an aircraft.

[0022] Fig. 2 schematically represents a cross-sectional view of a turbomachine.

[0023] Figure 3 represents a hybrid turbomachine electrical system in a configuration including three sources.

[0024] Fig. 4 schematically illustrates two voltage evolution templates.

[0025] Figure 5 schematically represents the interacting elements in a controller local area associated with an electrical source.

[0026] Figure 6 represents voltage thresholds associated with three electrical sources in a first configuration.

[0027] Figure [Fig.7] represents voltage thresholds associated with three electrical sources in a second configuration.

[0028] Figure [8] represents voltage thresholds associated with three electrical sources in a third configuration.

[0029] Figure 9 schematically represents a control loop of an electrical source.

[0030] Fig. 10 schematically represents an electrical system with two electrical sources and a local controller with two regulation loops.

[0031] Throughout the figures, similar elements bear identical references. DETAILED DESCRIPTION OF THE INVENTION

[0032] In the present application, upstream and downstream are defined with respect to the normal flow direction of the gas through the turbomachine. Furthermore, the longitudinal axis X of the turbomachine is the axis of rotation of its rotor parts. The axial direction corresponds to the direction of the longitudinal axis X, and a radial direction is a direction perpendicular to and passing through this axis.

[0033] By way of illustration, [Fig. 1] represents an aircraft 100 comprising at least one propulsion unit 1, in this case two propulsion units 1. The propulsion units 1 are attached and fixed to the aircraft 100, for example each under a wing of the aircraft 100 as illustrated, or alternatively on the wing of the aircraft 100 or even at the rear of the fuselage of the aircraft 100. The aircraft 100 is an airplane, but could alternatively be any other type of aircraft 100, for example a helicopter.

[0034] Aircraft electrical system 100

[0035] In a manner known per se, the aircraft 100 comprises a plurality of electrical loads (or receivers) powered by electrical sources via an electrical network.

[0036] An electrical load is a device powered by electrical energy, generally direct current or alternating current. It can be configured to transform the electrical energy that powers it into another form of energy, such as heat or mechanical energy.

[0037] With reference to [Fig. 3], the electrical loads can be divided into two categories. A first category of loads Chl is external to the propulsion system 1. The electrical loads Chl specific to the aircraft 100 may include, by way of example, an electric motor, a heating and / or air conditioning system, or a compressor. They enable, in particular, a number of functionalities, whether the aircraft is in flight or in operation on the ground, such as pressurizing and / or illuminating the cabin of the aircraft 100, or operating the cockpit.

[0038] A second category of loads is internal to the propulsion unit 1. The propulsion unit 1 generally includes a turbomachine 10, which will be described in detail later. The electrical loads Ch2 of the propulsion unit are loads of the turbomachine 10 (the "More Electric Engine" or MEE in Anglo-Saxon terminology). For example, the electrical loads of the turbomachine Ch2 may include a starter, variable geometry, or de-icing systems.

[0039] The plurality of electrical sources makes it possible to supply electrical loads with electrical energy, in the form of a continuous signal, typically a direct voltage.

[0040] On the one hand, the turbomachine 10 generally comprises two rotating bodies or shafts providing mechanical energy. Each shaft is associated with a generator motor allowing mechanical energy to be extracted from the associated shaft and converted into electrical energy, in order to supply the electrical network.

[0041] Furthermore, the aircraft 100 includes a plurality of electrical sources distributed throughout the aircraft 100, for example, an auxiliary power unit (APU), an electric battery, or a supercapacitor. These sources allow, in particular, for operation where the two shafts of the turbomachine 10 are assisted, but also for supplying various onboard systems on the ground (electrical voltage, pneumatic and hydraulic pressures, air conditioning) when the turbomachines 2 are stopped in order to save fuel, and during start-up.

[0042] The electrical network typically comprises a set of electrical conductors, typically a set of cables connecting the different electrical loads and the different sources, and bars, for example a high-voltage direct current distribution bus.

[0043] Generally, generator motors that extract mechanical energy from shafts produce alternating current. The alternating current is converted into direct current by an AC / DC converter. The electrical network includes at least a portion of a direct current network, with electrical loads being supplied by direct current.

[0044] Description of the turbomachine 10

[0045] Figure 2 schematically represents a section of the propulsion unit 1 in a plane containing the longitudinal axis X. The propulsion unit 1 comprises the turbomachine 10 and a nacelle 20 surrounding the turbomachine 10.

[0046] The propulsion unit 1 is intended to be mounted on the aircraft 100. In this regard, the propulsion unit 1 may include a pylon (not shown) intended to connect the propulsion unit 1 to a part of the aircraft 100, transmitting the forces to the aircraft 100.

[0047] This disclosure is not limited to a twin-spool, twin-flow turbojet with direct fan drive 11 as illustrated. It extends more generally to different turbojet architectures, including unfaired turbojets, and other types of turbomachinery, which may have a different number of bodies and / or flows.

[0048] The present disclosure falls more generally within the context of the internal hybridization of the turbomachine 10, i.e. presenting an electrical system 3 in interface with the mechanical shafts of the turbomachine 10 and the electrical network of the aircraft 100, as detailed later.

[0049] The turbomachine 10 comprises, from upstream to downstream in the direction of the gas flow, a blower 11, a compression section 16 comprising a low pressure compressor 161 and a high pressure compressor 162, a combustion chamber 14, an expansion section 15 comprising a high pressure turbine 152 and a low pressure turbine 151, and an exhaust casing.

[0050] Each of the low-pressure compressor 161, high-pressure compressor 162, high-pressure turbine 152, and low-pressure turbine 151 comprises a rotor portion and a stator portion, the rotor portion being capable of being driven in rotation relative to the stator portion about the longitudinal axis X. The blower 11, the rotor portion of the low-pressure compressor 161, and the rotor portion of the low-pressure turbine 151 are connected to each other by a low-pressure shaft 181 extending along the longitudinal axis X, thus forming a low-pressure body (LP body), which is a first rotating body. The rotor portion of the high-pressure compressor 162 and the rotor portion of the high-pressure turbine 152 are connected to each other by a high-pressure shaft 182 also extending along the longitudinal axis X, around the low-pressure shaft 181, thus forming a high-pressure body (HP body), which is a second rotating body. As seen in the [Fig.2], the compression section 16, the combustion chamber 14 and the expansion section 15 are surrounded by an engine casing 21, to which are connected the stator parts of the low pressure compressor 161, the high pressure compressor 162, the high pressure turbine 152 and the low pressure turbine 151. The engine casing 21 delimits a primary channel 13 allowing the flow of a primary gas flow A.

[0051] As explained previously, the longitudinal axis X defines the axis of rotation for the blower 11, the rotor parts of the compression section 16 and the rotor parts of the expansion section 15, in other words for the LP body and the HP body.

[0052] The nacelle 20 extends radially outside the turbomachine 10, around the longitudinal axis X, so as to surround the engine casing 21, and to define a secondary channel 12 allowing the flow of a secondary gas flow B.

[0053] The turbomachine 10 may also include at least one accessory gearbox (AGB), typically housed in a cavity within the nacelle 20. The accessory gearbox comprises a set of gears for rotating a plurality of shafts about their own axis, and accessories mounted on the plurality of shafts to derive useful mechanical power from their rotation. The gear set is itself driven by means of a radial drive shaft (RDS) connecting, optionally via a transfer case, the accessory gearbox to at least one of the high-pressure (HP) and low-pressure (LP) cylinders. For example, the radial drive shaft (not shown) can extend inside a longitudinal cavity formed within an arm 17. In this way, mechanical power can be taken from at least one of the high pressure body HP and the low pressure body BP to be delivered to at least one of the accessories via the accessory housing.

[0054] Fig. 3 illustrates an electrical system 3 distributed between the propulsion unit 1 and the aircraft 100 for supplying electrical power to external electrical loads Chl and / or internal electrical loads Ch2, typically by means of the direct current network.

[0055] The electrical system 3 makes it possible in particular to interface between the rotating bodies BP, HP of the turbomachine 10 and the electrical network of the aircraft 100. The electrical system is in particular configured to meet the electrical power requirements of the loads of the aircraft Chl and / or the turbomachine Ch2 by mechanically drawing power from the turbomachine 10, and to assist the starting and / or the in-flight operation of the turbomachine 10 using electrical sources from the aircraft 100.

[0056] In the embodiment illustrated in [Fig. 3], the electrical system 3 comprises three electrical sources. The low-pressure body BP is connected to an alternating current generator 31, coupled to the accessory housing of the low-pressure shaft 181. The high-pressure body HP is connected to an alternating current generator 32, coupled to the accessory housing of the low-pressure shaft 182. The electrical system 3 also comprises a direct current source 33, for example a battery.

[0057] More generally, this disclosure extends to any multi-source electrical system, comprising one or more alternating current electrical sources and / or one or more direct current electrical sources. In particular, electrical system 3 may not include the direct current source 33.

[0058] The alternating current generator 31, 32 and the direct current source 33 can each independently belong to the turbomachine 10, i.e. be controlled at the same time as the turbomachine 10, or even be controlled by the turbomachine 10. Alternatively or complementaryly, the electrical sources 31, 32, 33 can belong to the aircraft 100, i.e. be controlled at the same time as the aircraft 100.

[0059] Preferably, each electrical source 31, 32, 33 is associated with a respective converter 310, 320, 330, that is, with an element configured to supply electrical power. For example, the alternating current generator 31, 32 is associated with an AC / DC converter 310, 320 enabling the supply of direct current.

[0060] The electrical system 3 includes a distribution bus 30, connected to at least one of the external electrical load Chl and the internal electrical load Ch2, preferably to both loads Chl, Ch2.

[0061] Furthermore, each of the converters 310, 320, 330 is connected to the distribution bus 30.

[0062] The distribution bus 30 is configured to supply electrical power to the electrical load Chl, Ch2 in the form of a continuous signal in order in particular to meet the power requirements of the electrical load Chl, Ch2.

[0063] In fact, at least one, if not each, of the converters 310, 320, 330 is configured to regulate the distribution bus 30 in voltage from an electrical power supplied by the respective electrical source 31, 32, 33. The number and type of converters 310, 320, 330 and of electrical sources 31, 32, 33 is, of course, not limiting.

[0064] In order for the elements connected to the distribution bus 30, in particular the electrical loads Chl, Ch2 to function correctly, it is necessary to regulate the voltage of the distribution bus 30.

[0065] Bus voltage regulation

[0066] During operation, the electrical voltage within the distribution bus 30, or bus voltage Vdc, may vary around a given nominal value, or reference voltage Vref, for example, if an electrical load momentarily requires additional power, or if an electrical source disconnects. Therefore, the bus voltage Vdc must be regulated by a control system, controlling the power, or current, supplied by each electrical source 31, 32, 33 connected to the distribution bus 30.

[0067] In order to guarantee the quality of the electrical network, the bus voltage Vdc in the distribution bus 30 is framed by a template, defining upper and lower limits of voltage excursion around the reference voltage Vref, as a function of time, during the operation of the electrical system 3.

[0068] The template may include limits defined for normal and / or abnormal operating conditions, which limits surround, symmetrically or not, the nominal electrical voltage level, i.e. the reference voltage at the terminals of the distribution bus 30.

[0069] Two examples of a gauge are illustrated in [Fig. 4]. In a diagram showing the evolution of the electrical voltage as a function of time, a gauge boundary is typically represented as a line, broken or not. Preferably, even if the boundary does not define a constant electrical voltage value initially, particularly during the characteristic start-up time of the electrical system 3 or during the establishment time In a steady state during 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 distribution bus 30 and, consequently, of the electrical system 3. Such a template can, for example, be defined in a standard relating to the quality of the electrical system 3 and / or the DC network, but also be defined by a specification of the aircraft 100 to which the electrical system 3 is connected, typically the requirements of the manufacturer of the aircraft 100 and / or the turbomachine 1 in which the electrical system 3 is integrated.

[0070] Furthermore, the voltage regulation of the distribution bus 30 must be able to meet the power demands of the loads Chl, Ch2 connected to the distribution bus 30. Typically, when the amount of power drawn by at least one load Chl, Ch2 from the distribution bus 30 is greater than the amount of power injected into the distribution bus 30 by at least one converter 310, 320, 330, the voltage of the distribution bus 30 decreases significantly. Conversely, when the amount of power injected by at least one converter 310, 320, 330 into the distribution bus 30 is greater than the amount of power drawn from the distribution bus 30 by at least one load Chl, Ch2, the voltage of the distribution bus 30 increases. Thus, regulating the voltage of the distribution bus 30 makes it possible, in addition to ensuring the safety of the electrical system 3, to meet the power requirements of the loads Chl, Ch2.In other words, each of the converters 310, 320, 330 is configured to continuously adapt the power it injects or draws from the distribution bus 30, according to the voltage of the distribution bus 30, so as to meet exactly the power requirements of the loads Chl, Ch2 connected to the distribution bus 30.

[0071] This injection or extraction of power from the distribution bus 30 by the converters 310, 320, 330 is made possible in particular by their connection with the electrical sources 31, 32, 33. In fact, at least one, if not each, of the alternating current generators 31, 32 is connected to a rotating body BP, HP, of the turbomachine 1 to allow an exchange of mechanical and / or electrical power between the rotating body BP, HP and the alternating current generator 31, 32, preferably to extract mechanical power from the rotating body BP, HP and transform it into electrical power, which electrical power is then delivered to the first converter 310 and / or the second converter 320 to be injected onto the distribution bus 30. In the embodiment illustrated in [Fig. 3], the first alternating current generator 310 is connected to the body BP, while the second alternating current generator 320 is connected to the body HP.

[0072] Since the electrical power supplied by the alternating current generators 31, 32 is in the form of an alternating signal, each of the first and second Converter 310, 320 is configured to reversibly transform this alternating signal into a direct signal suitable for injection, and then circulation, on the distribution bus 30, when the distribution bus is supplied with direct current.

[0073] Similarly, the DC power source 33 can deliver power in the form of a continuous signal to the third converter 330, which will nevertheless convert it, also reversibly, to shape it according to the constraints specific to the distribution bus 30, and then inject it onto the distribution bus 30.

[0074] Each, or at least one, of the alternating current generators 31, 32 can, for example, be a wound-rotor synchronous machine, typically comprising three stages (or "Variable Frequency Generator", VGF in Anglo-Saxon terminology), driven by at least one of the high-pressure shaft 182 and the low-pressure shaft 180 of the turbomachine 1, typically via the accessory gearbox. Other types of electrical machines are conceivable, such as, preferably, permanent-magnet synchronous machines (or "Permanent-Magnet Synchronous Machine Drives", PMSM in Anglo-Saxon terminology), which have the particular advantage of having a lower mass, or such as induction machines (or "Induction machines" in Anglo-Saxon terminology) or variable reluctance machines.

[0075] The DC power source 33 may, for its part, comprise a battery, a supercapacitor, a DC generator, and / or a fuel cell. The DC power source 33 makes it possible, in particular, to relieve the rotating bodies BP, HP, or to take over from them, when, for example, the current draw required to meet the power needs of the loads Chl, Ch2 is too high, but also to absorb certain dynamics, such as sudden variations in the behavior of the loads Chl, Ch2.

[0076] The electrical system 3 includes a control system for controlling the electrical sources 31, 32, 33 connected in parallel on the distribution bus 30.

[0077] The control system includes a central regulator 40 and a plurality of local controllers 311, 321, 331. As illustrated in [Fig.3], each converter 310, 320, 330 is connected to, or integrates, a respective local controller 311, 321, 331.

[0078] In a power-sharing context between sources, the central regulator 40 is configured to generate, at a center frequency Fc, a total setpoint Ptot, from a measurement Vmes of the bus voltage Vdc and the reference voltage Vref. The total setpoint Ptot is calculated so that the electrical sources 31, 32, 33 connected to the distribution bus 30 together supply the power required by the loads Chl, Ch2.

[0079] From the total setpoint Ptot and a setpoint for power distribution (or sharing) between the electrical sources 31, 32, 33, the central regulator 40 is then configured to generate, at the central frequency Fc, local setpoints P respectively associated with the electrical sources 31, 32, 33.

[0080] The center frequency Fc is limited by the bandwidth available in the communication buses linking the central regulator 40 to the various local controllers 311, 321, 331.

[0081] The central regulator 40 is preferably connected to a voltage sensor 5 allowing the measurement of Vmes of the distribution bus 30.

[0082] One possible embodiment is illustrated in [Fig.3]. Preferably, the central regulator 40 comprises a voltage control unit 41 and a power sharing unit 42.

[0083] The voltage control unit 41 is designed to regulate the bus voltage Vdc at the terminals of the distribution bus 30 around the reference voltage Vref. Typically, the reference voltage value Vref is between 500V and 1000V, for example 800V. In other words, the voltage control unit 41 is configured to provide the central setpoint Ptot corresponding to the total power that the various electrical sources 31, 32, 33 must supply together.

[0084] The power sharing unit 42 is then configured to distribute the total power to be supplied between the different electrical sources 31, 32, 33. For example, each source is associated with a coefficient XI, X2, X3, corresponding to the percentage of power supplied by each source, so that XI + X2 + X3 = 1. With reference to [Fig.3], the local setpoint P transmitted by the central regulator 40 to the electrical source 31 is, for example, P = XI x Ptot, the setpoint P transmitted to the electrical source 32 is X2 x Ptot and that transmitted to the electrical source 33 is X3 x Ptot.

[0085] In the case of a configuration with two sources, as illustrated in [Fig. 10], the central computer 4 transfers a power distribution setpoint of X % to the power sharing unit 42. We then have a local setpoint for the first source equal to XI x Ptot, with XI = X, and a local setpoint for the second source equal to X2 x Ptot, with X2 = 1-X.

[0086] The central regulator 40 receives a signal corresponding to the measurement Vmes, which represents the voltage across the distribution bus 30. The voltage control unit 41 is, for example, connected to the voltage sensor 5. The Vmes measurement can be received via a physical or wireless connection. The sensor 5 can perform a Vmes measurement at the center frequency Fc. The Vmes measurement represents, in particular, the evolution of the power requirements of the loads Chl, Ch2 connected to the distribution bus 30. Typically, when a load Chl, Ch2 suddenly requires a significant amount of power to be drawn from the distribution bus 30, due to Due to the response time of the electrical system 3 to supply the distribution bus 30 with the necessary power to compensate for the power drawn, the voltage of the distribution bus 30 will drop sharply, and this drop will be reported to the control system via the Vmes measurement, at the center frequency Fc. Similarly, when a load Chl, Ch2 suddenly sheds a significant amount of power from the distribution bus 30, due to the response time of the electrical system 3 to draw the necessary power from the distribution bus 30 to compensate for this load shedding, the voltage of the distribution bus 30 will rise sharply, and this rise will be reported to the control system via the Vmes measurement. Thus, the Vmes measurement is typically a time signal, that is, representing the evolution of the bus voltage Vdc of the distribution bus 30 as a function of time.Many Chl and Ch2 charges, particularly so-called "active" charges, typically a de-icing system, can exhibit this type of dynamic behavior, which can also vary during the different phases of flight.

[0087] In the embodiment illustrated in [Fig. 3], the control system further comprises a central computer 4. The central computer 4 may, for example, be all or part of the system providing the interface between the aircraft cockpit 100 and the turbomachine 10 (or "Full Authority Digital Engine Control," FADEC, in Anglo-Saxon terminology), typically being the control unit of the turbomachine 10 ("Electronic Control Unit" or ECU in Anglo-Saxon terminology), integrated into the FADEC. Alternatively or additionally, the bus voltage measurement Vmes may be measured by the central computer 4. The central computer 4 is connected to the control system, i.e., to the central regulator 40, in this case to the power sharing unit 42. The central computer 4 is typically configured to generate the power distribution setpoint between the electrical sources 31, 32, 33.In other words, the central computer 4 can determine additional constraints that the electrical system 3 must meet in order to satisfy the power requirements of the loads Chl, Ch2. Thus, the central computer 4 can transmit to the power sharing unit 42 a plurality of respective thresholds associated with the electrical sources (called "setpoints" in English).

[0088] The central computer 4 can transmit a power distribution instruction corresponding to the power draw between the rotating elements BP, HP and the DC power source 33. The distribution instruction tells the central controller 40 how the total power to be drawn from the turbomachine 10 to meet the load requirements of Chl, Ch2 should be distributed between the rotating elements BP, HP and the DC power source 33, and can typically take the form of a percentage. In the example described above, the central computer 4 provides the power sharing unit 42 with the values ​​of the coefficients XI, X2, X3, for example.

[0089] The central computer 4 can thus transmit a voltage margin AV], AV2, AV3 of local control activation to each of the local controllers 311, 321, 331. In the embodiment shown, the central computer 4 transmits information via the power sharing unit 42, itself connected to each of the local controllers 311, 321, 331. The voltage margin AVP AV2, AV3 is specific to each power source 31, 32, 33. The voltage margins AVf, AV2, AV3 determine an permissible deviation value from the reference voltage value Vref. Preferably, the voltage margin AV2, AV3 may correspond to a tolerance on a voltage measurement error of sensor 5. Typically, the voltage margin is between 1% and 5% of the reference voltage value Vref, typically 2% of the bus voltage Vdc.

[0090] In general, the central regulator 40, for example via the power sharing unit 42, transmits to each of the local controllers 311, 321, 331 a local setpoint P. Typically, the local setpoint P corresponds to a power, or a torque, or even a current.

[0091] The control system is configured to compensate for changes in the Vdc voltage of the distribution bus 30 by the action of the converters 310, 320, 330, and in particular to maintain the voltage of the distribution bus 30 within the limits allowing stable operation of the electrical system 3.

[0092] To do this, each local controller 311,321,331 is configured to generate, at a local frequency Fl, higher than the center frequency Fc, an output setpoint Pc from the received local setpoint (P).

[0093] Preferably, the local frequency Fl is at least five times higher than the center frequency Fc. Typically, the center frequency Fc is between 10 Hz and 100 Hz. The local frequency Fl is greater than 100 Hz, preferably between 500 Hz and 2 kHz.

[0094] Thus, each of the converters 310, 320, 330 receives from the respective local controller 311, 321, 331 the output setpoint Pc which is specific to it, and from which the converter 310, 320, 330 regulates the voltage of the distribution bus 30. The combination of the regulations of each converter 310, 320, 330 thus makes it possible to continuously monitor the power requirements of the loads Chl, Ch2.

[0095] Voltage regulation by the local controllers 311, 321, 331 is activated according to a threshold logic, with minimum and maximum setpoints generated at the local frequency Fl. This allows for faster regulation of the distribution bus voltage 30, compared to an electrical system comprising a conventional centralized control architecture.

[0096] More specifically, each local controller 311, 321, 331 is configured to: • generate a first threshold value V1 lower than the reference voltage Vref and a second threshold value V2 higher than the reference voltage; • generate at the local frequency Fl a minimum setpoint PI from the first threshold value VI and the measurement Vmes; • generate at the local frequency Fl a maximum setpoint P2, from the second threshold value V2 and the measurement Vmes.

[0097] Each local controller 311, 321, 331 is then configured to generate the output setpoint Pc from the received local setpoint P, so that the output setpoint Pc is equal to: • the local setpoint P if the local setpoint P is greater than the minimum setpoint PI and less than the maximum setpoint P2; • the minimum setpoint PI if the local setpoint P is less than the minimum setpoint PI; • the maximum setpoint P2 if the local setpoint P is greater than the maximum setpoint P2.

[0098] Since the local frequency Fl at which the respective local controllers 311, 321, 331 generate the output setpoint Pc is higher than the central frequency Fc, the control system can, in the event of a strong power surge on the distribution bus 30, react more quickly than if it comprised only the central regulator 40 or the central computer 4. A bus voltage excursion Vdc is limited, so that the bus voltage Vdc at the terminals of the distribution bus 30 remains within acceptable limits. Another advantage is that it allows regulation of the distribution bus 30 even in the event of a loss of the centralized central regulator 40.

[0099] Preferably, the local controller 311, 321, 331 also includes an internal control loop CONT, configured to transmit an appropriate setpoint to the associated converter 310, 320, 330, from the output setpoint Pc.

[0100] Generation of threshold values

[0101] In the illustrated embodiment, the local controller 311, 321, 331 further includes a voltage threshold definition unit Ds. The voltage threshold definition unit Ds defines the first threshold value VI and the second threshold value V2. The central computer 4 can transmit the voltage margin AVp AV^ AV3 to the voltage threshold definition unit Ds of each local controller 311, 321, 331.

[0102] More generally, the generation of threshold values ​​by each local controller 311, 321, 331 can be static, i.e. independent of the engine speed of the turbomachine 10 or of the loads Chl, Ch2.

[0103] Preferably, the generation of threshold values ​​by each local controller 311, 321, 331 is dynamic, that is to say that its value evolves over time, typically at the local frequency Fl.

[0104] For example, the threshold value is frequently calculated based on several parameters, for example the state of the electrical sources, and / or the voltage margins AVv AV2, AV3 provided by the central computer 4, and / or a setpoint from the central computer 4. In this embodiment, the voltage threshold definition unit Ds can communicate with the power sharing unit 42 and / or the central computer 4.

[0105] For example, the electrical system 3 includes a network supervision unit, for example a generator control unit (or GCU). For example, the supervision unit can communicate with an electrical network management function (or ENMF) controlling the various contactors of the electrical system 3.

[0106] The network supervision unit can communicate to the local controller 311, 321, 331, and in particular to the voltage threshold definition unit Ds information on the state of the electrical system 3, and in particular the disconnection of certain electrical sources, so that the voltage threshold definition unit Ds calculates the first threshold value VI and / or the second threshold value V2 according to the number of electrical sources connected.

[0107] Preferably, the central computer 4 can reduce the AVv voltage margin AV2, AV3 associated with an electrical source 31, 32, 33, for example according to the flight phases or the state of the turbomachine 10. Reducing the AV voltage margin of a source makes it easier to use, as will be seen later.

[0108] Generation of minimum and maximum setpoints

[0109] From the first threshold value VI, the local controller 311, 321, 331 generates the minimum setpoint PI. From the second threshold value V2, the local controller 311, 321, 331 generates the maximum setpoint P2.

[0110] With reference to [Fig.5], each local controller 311, 321, 331 preferably includes a first control loop BC1 and a second control loop BC2, the first control loop BC1 being intended to take as input the first threshold value VI and the measurement Vmes and to provide as output the minimum setpoint PI, and the second control loop BC2 being intended to take as input the second threshold value V2 and the measurement Vmes and to provide as output the maximum setpoint P2.

[0111] The use of local feedback loops makes it possible to slow down the bandwidth of a centralized feedback loop and thus slow down the sampling of the central regulator 40 as well as the transmission speed of the communication buses between the central regulator 40 and the local controllers 311, 321, 331.

[0112] For example, the voltage threshold definition unit Ds provides the first regulation loop BC1 with the first threshold value Vb lower than the value of Reference voltage Vref. Preferably, the first threshold value V1 is calculated from the voltage margin AV and the reference voltage value Vref provided by the voltage sharing unit 42. Typically, VI = Vref. The output of the first control loop BC1 then corresponds to the minimum setpoint PI. Typically, the minimum setpoint PI corresponds to a minimum power, torque, or current to be achieved.

[0113] For example, the voltage threshold definition unit Ds provides the second control loop with a second threshold value V2, higher than the reference voltage value Vref. Preferably, the second threshold value V2 is calculated from the voltage margin AV and the reference voltage value Vref provided by the voltage sharing unit 42. Typically, V2 = Vref + AV. The output of the second control loop then corresponds to the maximum setpoint P2. Similarly, the maximum setpoint P2 corresponds to a maximum power, torque, or current that can be drawn from the associated source.

[0114] Obtaining the output of the first regulation loop BC1 corresponding to maximum voltage regulation is illustrated in [Fig.9]. Obtaining the output of the second regulation loop BC2 can be done in a similar way.

[0115] Preferably, the first control loop BC1 and the second control loop BC2 are zero static error control loops, in particular of the 'proportional integral' type.

[0116] Such a BC1, BC2 control loop comprises, in a manner known per se, a proportional gain Kp and an integral gain Ki. The threshold value VI, V2 is injected into the BC1, BC2 control loop. The local controller calculates the difference between the threshold value and a representative value of the actual state of the electrical system 3. The representative value is obtained from a voltage measurement at the output of the electrical system 3.

[0117] The representative value may depend on the voltage measurement Vmes transmitted by the sensor 5. For example, it may correspond to the voltage measurement Vmes across the terminals of the distribution bus 30, multiplied by a factor representing an uncertainty in the measurement.

[0118] Preferably, each power source 31, 32, 33 is associated with a local sensor 51, 52, 53 configured to provide the associated local controller 311, 321, 331 with a local voltage measurement Vloc1, Vloc2, Vloc3. The local voltage measurement Vloc1, Vloc2, Vloc3 is typically close to the measured bus voltage Vmes, but may not be equal to the bus voltage Vmes measured across the distribution bus 30, due to the impedance of the cables connecting the power sources 31, 32, 33 to the distribution bus 30.

[0119] The value of the PI output, P2 is obtained as the sum of the difference multiplied by the proportional gain Kp, and the integral of the difference multiplied by the integral gain Ki.

[0120] Preferably, the first control loop BC1 and / or the second control loop BC2 uses an integral anti-saturation correction term. More generally, the local controller 311, 321, 331 may include an "antiwindup" device to prevent integral saturation. Indeed, in zero-error control loops, the presence of a non-linearity limiting the setpoint Pc downstream of the control loop, typically saturation induced by a MIN or MAX block, can generate an error between the threshold value VI, V2 serving as a reference, and the measured value Vmes. The integral input is therefore non-zero, which causes the integral to drift.

[0121] Generally, the BC1, BC2 control loop is not active, meaning that the setpoint Pc supplied to the associated converter 310, 320, 330 will not be equal to the output PI, P2 of the BC1, BC2 control loop. Thus, the presence of the "anti-windup" device advantageously prevents the integral from drifting. The desaturation of the integrated term is obtained by adding to the product of the difference with the integral gain Ki a correction term corresponding to the difference between the setpoint Pc and the output of the PI, P2 control loop, multiplied by a gain Awl, Aw2.

[0122] The proportional gains Kp, and integral Ki of the different regulation loops BC1, BC2 and implemented by the voltage control unit 41 identified in figures 9 and 10 may have different values.

[0123] Generation of output setpoint Pc

[0124] The output setpoint Pc for the control of the electrical source 31, 32, 33 associated with the local controller 311, 321, 331 depends on the local setpoint received P at the center frequency Fc, and on the maximum setpoint P2 and minimum setpoint PL. For example, the setpoint Pc supplied by the local controller 311, 321, 331 to the associated converter 310, 320, 330 depends on the outputs of the control loops BC1, BC2.

[0125] More generally, the setpoint Pc transmitted by the local controller 311, 321, 331 is between the minimum setpoint PI and the maximum setpoint P2.

[0126] In the illustrated embodiment, the local controller 311, 321, 331 further includes a saturation unit S. The saturation unit S is configured to transmit to the converter 310, 320, 330, or preferably to the internal control loop CONT, a setpoint Pc as a function of the local setpoint P, the maximum setpoint P2, and the minimum setpoint PL

[0127] Preferably, the output setpoint Pc is generated via a 'MAX' type block connected to the output of the first control loop BC1. The 'MAX' block is configured to provide a maximum output between the output of the first loop BC1 regulation and the local setpoint P. The 'MAX' block thus acts as a maximum selector. The setpoint Pc is then generated based on the output of the 'MAX' block.

[0128] Typically, the saturation unit S implements the "MAX" function. In this case, Pc = max(P,Pl). Thus, the setpoint Pc provided by the local controller 311, 321, 331 cannot be less than the minimum setpoint PI, specifically the output of the first control loop BC1. This allows the setpoint Pc to be limited by the minimum setpoint PI required to limit the voltage drop on the distribution bus 30.

[0129] Preferably, the output setpoint Pc is generated via a 'MIN' type block connected to an output of the second control loop BC2. The 'MIN' block, or minimum selector, is configured to provide an output that is a minimum between the output of the second control loop BC2 and the local setpoint P. The setpoint Pc is then generated based on the output of the 'MIN' block.

[0130] Typically, the saturation unit S implements the "MIN" function. In this case, Pc = min(P,P2). Thus, the setpoint Pc provided by the local controller 311, 321, 331 cannot exceed the maximum setpoint P2 to be maintained. This limits the rise in the distribution bus voltage 30.

[0131] Preferably, the local controller 311, 321, 331 includes both the 'MIN' block and the 'MAX' block. If one of the BC1 or BC2 control loops is activated, then the transmitted setpoint Pc will be equal to the output of the activated BC1 or BC2 control loop. The two control loops cannot be activated simultaneously.

[0132] Example of dynamic modification of threshold values

[0133] An illustration of the threshold scaling for the different sources is shown in Figures 6 and 7. It is assumed that the voltage margin AV is identical for the three electrical sources 31, 32, 33.

[0134] In the first case, illustrated in [Fig. 6], the first threshold value VI and the second threshold value V2 are identical for the three electrical sources 31, 32, 33. All the local controllers 311, 321, 331 receive the same setpoint. There is no priority among the three local electrical sources.

[0135] In the second case, the DC current source 33 has different threshold values ​​than the AC current sources 31, 32 associated with the BP, HP bodies, respectively. For example, for the DC current source 33, the first threshold value VI is higher than the first threshold value of the other sources 31, 32, while the second threshold value V2 is lower than the second threshold value of the other sources 31, 32. Typically, in Figure 7, for the DC current source 33, we have VI = Vref - AV and V2 = Vref + AV, and for the sources 31, 32, we have VI = Vref - 2AV and V2 = Vref + 2AV.

[0136] Equivalently, the power sharing unit 42 can transmit different AV voltage margin values ​​h AV2, AV3 for each power source 31, 32, 33. The power source corresponding to a lower AV voltage margin will be used as a priority in the event of a strong power impact or in the event of a loss of the central regulator 40.

[0137] Preferably, each local controller 311, 321, 331, typically via the threshold definition unit Ds, is configured to stagger the voltage threshold values ​​between the different power sources. This prevents the local controllers of the power sources from "force fighting" in the event of a loss of the central regulator 40, provided they have zero steady-state error. This limits the risk of power sharing drift between the different power sources 31, 32, 33.

[0138] More generally, as illustrated in [Fig. 7], the local controller 311, 321, 331 can, for example, tighten the thresholds of a source, here source 33, which is to be given priority. As before, the scaling of the voltage thresholds can be static, i.e., predefined in advance, or dynamic, i.e., calculated frequently, typically by the voltage threshold definition unit Ds as a function of several parameters.

[0139] Generally speaking, "tightening the threshold of an electrical source" means increasing the first threshold value VI associated with the electrical source and reducing the second threshold value V2 associated with it, so as to bring the threshold values ​​closer to the reference voltage Vref. Equivalently, this amounts to increasing the minimum setpoint PI to be maintained and reducing the maximum setpoint P2 to be maintained.

[0140] Typically, depending on the flight phase, the available electrical sources are not the same. For example, when the aircraft 100 is on the ground, battery 33 is the only available electrical source. During taxiing and when starting the propulsion unit 10, the auxiliary power unit is also available and is preferred, with battery 33 remaining as a backup. During other flight phases (takeoff, cruise, and landing), the electrical sources 31 and 32 connected to the high-pressure and low-pressure components of the propulsion turbomachine are preferred for controlling the voltage of the distribution bus 30. Battery 33 and / or the auxiliary power unit are used as backups.

[0141] Preferably, a local controller associated with a priority power source is configured to increase the first threshold value V1 and / or decrease the second threshold value V2, in the event of a communication breakdown between the local controller and the central regulator 40, as illustrated in [Fig.8].

[0142] For example, the voltage threshold definition unit Ds can tighten the threshold of a single electrical source around the reference voltage value Vref, in the case detection of communication interruption or operation of the central regulator 40 and / or the central computer 4. This advantageously allows priority to be given to the electrical source whose voltage thresholds are tightened around the reference value Vref, in the case illustrated on [Fig.8], the electrical source 31 associated with the low pressure rotating body BP.

[0143] Preferably, each local controller 331, 321, 331 is configured to reduce the first threshold value VI if the output setpoint Pc is equal to the minimum setpoint PI for a duration exceeding a limit time, and / or to increase the second threshold value V2 if the output setpoint Pc is equal to the maximum setpoint P2 for a duration exceeding the limit time. In other words, the voltage threshold setting unit Ds can tighten the threshold of a power source if the first control loop BC1 and / or the second control loop BC2 of the associated local controller remain activated for too long, typically for a duration exceeding 5 s, preferably for a duration exceeding 1 s. Since the output setpoint Pc can be updated at the very high local frequency Fl, this generally corresponds to the activation of the same control loop BC1, BC2 for more than 100 iterations.In other words, if the setpoint value Pc remains equal to the minimum setpoint PI and / or the maximum setpoint P2 for too long, the value of the first threshold VI will be increased and / or the value of the second threshold V2 will be reduced.

[0144] Preferably, the electrical system 3 includes an external computer capable of modifying the voltage margins AV15, AV2, AV3, or equivalently, the threshold values, based on various information. Typically, the external computer can take into account information on the state of the electrical system, for example, the state of the contactors on the distribution bus 30, or a voltage level across the distribution bus 30 or across the electrical sources 31, 32, 33. The external computer can preferably take into account the threshold values ​​associated with the other electrical sources 31, 32, 33.

[0145] For example, the external computer can be the electrical heart of the aircraft 100 which will interface with the various electrical sources 31, 32, 33. This makes it possible to coordinate threshold values ​​and to compensate for a deficiency in the central regulator 40.

[0146] Acceleration of regulation by the central regulator

[0147] Preferably, the central regulator 40 includes a central control loop with zero static error, in particular of the 'proportional-integral' type. The central control loop illustrated in [Fig. 9] takes as input the measured bus voltage Vdc and the reference voltage Vref, and generates as output the local setpoints P transmitted to each local controller 311, 321, 331.

[0148] As before, the local setpoint P is calculated from the sum of two terms. The first term is the difference between the voltage value The reference voltage is measured and multiplied by a proportional gain Kp. The second term is the difference, multiplied by an integral gain Ki, before being integrated.

[0149] Preferably, the central control loop uses an integral anti-saturation correction term. Typically, the voltage control unit 41 includes an "anti-windup" type device. Thus, the term multiplied by the integral gain Ki can be added to the integral anti-saturation correction term before being integrated.

[0150] The anti-windup device integrated into the voltage control unit 41, or more generally the integral anti-saturation correction term of the central control loop, offers a technical advantage. Indeed, when one of the BC1, BC2 control loops of the local controller 311, 321, 331 is activated, the setpoint Pc supplied to the associated converter 310, 320, 330 does not depend directly on the local setpoint value P, but rather on the output of the activated BC1, BC2 control loop (i.e., is equal to PI or P2). A drift of the integrator may not be observed insofar as the local controller 311, 321, 331 advantageously includes an integral anti-saturation correction term, as explained previously, and thus can perform the same function as the central controller 40.However, the central controller 40 may be slow to catch up with the local control loop BC1, BC2, because the central frequency Fc is lower than the local frequency Fl. The "antiwindup" type device of the central controller 40 advantageously accelerates the integral term in the calculation of the local setpoint P by the central controller 40, in a roundabout way.

[0151] In a multi-source embodiment as illustrated, the antiwindup device of the central regulator 40 can correspond to a correction term multiplied by a central antiwindup coefficient Awc added to the term multiplied by the integral gain Ki before integration.

[0152] The correction term advantageously represents the difference between the total setpoint Ptot from the central controller 40, typically from the voltage control unit 41 before power sharing by the power sharing unit 42, and the controlled local powers Pc. Typically, as illustrated in [Fig. 10] in the case of two sources, the correction term can correspond to the difference between the sum of the local setpoints Pc of the different sources and the central setpoint Ptot provided by the power control unit 41 before power sharing by the power sharing unit 42. Alternatively, the correction term can correspond to the sum of the differences between the local setpoints P and the setpoints Pc transmitted to the local controllers.

[0153] To illustrate this behavior, a simplified case with a single source 31 and a voltage control unit 41 described previously is shown in [Fig. 9]. The Local controller 311 includes a single BC1 regulation loop, here a minimum voltage regulation loop with a "MAX" block. The power sharing unit 42 is not required here, we have Ptot = P.

[0154] One advantage of the invention, however, lies in the power sharing for a 3-source electrical system.

[0155] Example of implementation of the regulation process

[0156] An example of implementation of the control system described above for controlling the voltage Vdc at the terminals of the distribution bus 30 is described here.

[0157] It is assumed that the reference voltage is Vref = 800 V. At t = 1s, a voltage drop is observed at the distribution bus 30. This can be explained by a change in the demand of the electrical loads Chl, Ch2, or the disconnection of an electrical source.

[0158] The voltage drops rapidly because the central regulator 40 is too slow to react (Pc = P). When the measured voltage falls below VI = 780 V, the local regulation loop BC1 activates and takes over. It regulates the voltage to 780 V (Pc = PI). Preferably, the antiwindup device of the centralized voltage control unit 41 detects a difference between the local setpoint P and the actual setpoint Pc. It adds the difference via the antiwindup coefficient Awc in order to increase the value of the integral. This has the effect of bringing the distribution bus voltage 300 back to the reference voltage (800 V) more quickly. When P > PI, the central regulator 40 takes over again and brings the voltage Vdc at the distribution bus terminals back to 800 V (Pc = P).

[0159] In general, the present invention can be generalized to any electrical system comprising any number of electrical sources connected in parallel on a distribution bus 30 of the same voltage level.

[0160] The type of electrical source used in the electrical network 3 is not limited to the electrical sources shown. In particular, non-reversible or reversible electrical sources may be used.

[0161] The generation of the maximum P2 and minimum PI setpoints by the local controller 311, 321, 331 is not limited to a proportional-integral type controller as illustrated. Each local controller can implement other voltage control strategies, preferably with zero steady-state error.

[0162] For example, the BC1, BC2 regulation loop and / or the voltage control unit 41 may include proportional-integral-derivative (PID) type feedback, i.e. a PI feedback loop as illustrated in [Fig.9], in which a third term from the differentiation of the difference Vref-Vmes, multiplied by a gain Kd, is also added to the sum of the proportional and integral terms.

[0163] For example, the BC1, BC2 control loop may include a linear quadratic controller (LQR), a linear quadratic Gaussian controller (LQG), which is a combination of a linear quadratic controller and a Kalman filter allowing state estimation. Alternatively, the BC control loop may include an optimal controller of type H00 or even an active disturbance rejection control (ADRC) feedback.

[0164] More generally, the voltage regulator of the distribution bus 30 is not limited to the electrical system 3 of the aircraft 100 but can extend to any electrical system comprising a plurality of electrical sources connected in parallel with centralized control.

Claims

1. Demands Control system for controlling electrical sources connected in parallel on a distribution bus (30), the distribution bus (30) having a bus voltage (Vdc) to be regulated around a reference voltage (Vref), the control system comprising: a central regulator (40) configured to generate, at a center frequency (Fc), a total setpoint (Ptot) from a measurement (Vmes) of the bus voltage (Vdc), and from the reference voltage (Vref), and local setpoints (P) respectively associated with the electrical sources from the total setpoint (Ptot) and a power distribution setpoint between the electrical sources; local controllers (311, 321, 331) in communication with the central regulator (40), each local controller (311, 321, 331) being associated with an electrical source, and configured to: • generate a first threshold value (VI) lower than the reference voltage (Vref) and a second threshold value (V2) higher than the reference voltage; • generate at a local frequency (Fl) a minimum setpoint (PI) from the first threshold value (VI) and the measurement (Vmes); • generate at the local frequency (Fl) a maximum setpoint (P2), from the second threshold value (V2) and the measurement (Vmes), the local frequency (Fl) being greater than the center frequency (Fc); • generate an output setpoint (Pc) from one of the local setpoints (P), such that the output setpoint (Pc) is equal to: the local setpoint (P) if the local setpoint (P) is greater than the minimum setpoint (PI) and less than the maximum setpoint (P2); the minimum setpoint (PI) if the local setpoint (P) is less than the minimum setpoint (PI); • the maximum setpoint (P2) if the local setpoint (P) is greater than the maximum setpoint (P2). • control the associated power source using the output setpoint (Pc).

2. Control system according to claim 1, wherein each local controller (311,321,331) comprises • a first control loop (BC1) configured to take as input the first threshold value (VI) and the measurement (Vmes) and provide as output the minimum setpoint (PI), and • a second control loop (BC2) configured to take as input the second threshold value (V2) and the measurement (Vmes) and provide as output the maximum setpoint (P2).

3. Control system according to claim 2, wherein the first control loop (BC1) and the second control loop (BC2) are zero static error control loops, for example proportional-integral control loops.

4. Control system according to any one of claims 2 and 3, wherein the first control loop (BC1) and / or the second control loop (BC2) uses an integral anti-saturation correction term.

5. Control system according to any one of claims 2 to 4, wherein each local controller (311,321,331) comprises: • a maximum selector configured to provide at output a maximum between the output of the first control loop (BC1) and the local setpoint (P), and • a minimum selector configured to provide at output a minimum between the output of the second control loop (BC2) and the local setpoint (P), the output setpoint (Pc) being generated by each local controller (311,321,331) via the maximum selector and the minimum selector.

6. A control system according to any one of claims 1 to 5, wherein each local controller (311, 321, 331) is configured to generate at least one of the first threshold value (VI) and the second threshold value (V2) dynamically according to a setpoint from a central computer (4).

7. Control system according to any one of claims 1 to 6, wherein each local controller (331,321,331) is configured to reduce the first threshold value (VI) if the output setpoint (Pc) is equal to the minimum setpoint (PI) for a duration greater than a limit time, and / or to increase the second threshold value (V2) if the output setpoint (Pc) is equal to the maximum setpoint (P2) for a duration greater than the limit time.

8. Control system according to any one of claims 1 to 7, wherein at least one local controller (311) is configured to increase the first threshold value (VI) and / or decrease the second threshold value (V2), in the event of a communication breakdown of the local controller (311) with the central regulator (40).

9. Control system according to any one of claims 1 to 8, wherein the central regulator (40) comprises a central control loop with zero static error, in particular a proportional-integral control loop, taking as input the measured (Vmes) bus voltage (Vdc) and the reference voltage (Vref), and generating at output the total setpoint (Ptot).

10. Control system according to the preceding claim, wherein the central control loop uses an integral antisaturation correction term, the correction term being representative of the difference between the total setpoint (Ptot) and the local setpoints (Pc).

11. Control system according to any one of claims 1 to 10, wherein the local frequency (Fl) is at least five times greater than the center frequency (Fc).

12. An electrical system comprising • a distribution bus (30) to which at least one electrical load (Chl) is intended to be connected, • electrical sources (31, 32, 33) intended to supply current to the distribution bus (30), and • a control system according to any one of claims 1 to 11, in which the local controllers (311,321,331) are respectively associated with the electrical sources (31,32,33), the current supplied by each electrical source (31,32,33) depending on the output setpoint (Pc) generated by the associated local controller (311,321,331).

13. A method for regulating the voltage of a distribution bus (30) connecting power sources (31, 32, 33), implemented by a central regulator (40) and by local controllers (311, 321, 331) associated respectively with the power sources (31, 32, 33), the regulation method comprising the steps of: generation, by the central regulator (40), of a total setpoint (Ptot) from a measurement of the bus voltage (Vdc) and a reference voltage (Vref), and of local setpoints (P) transmitted respectively to the local controllers (311, 321, 331), from the total setpoint (Ptot) and a power distribution setpoint, the total setpoint (Ptot) and the local setpoints (P) being generated at a central frequency (Fc), generation, by each local controller (311, 321, 331), of a minimum setpoint (PI) from a first threshold value (VI) lower than the reference voltage (Vref), and of a maximum setpoint (P2) from a second threshold value (V2) higher than the reference voltage (Vref), at a local frequency (Fl), the local frequency (Fl) being higher than the central frequency (Fc), generation, by each local controller (311,321,331), of an output instruction (Pc) from a received local instruction (P),the output setpoint (Pc) being equal to: • to the local setpoint (P), if the local setpoint (P) is greater than the minimum setpoint (PI) and less than the maximum setpoint (P2); • to the minimum setpoint (PI) if the local setpoint (P) is less than the minimum setpoint (PI); • and to the maximum setpoint (P2) if the local setpoint (P) is greater than the maximum setpoint (P2), • control, by each local controller (311, 321, 331), of the electrical source (311,32,33) associated with the output instruction (Pc).

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