SYSTEM FOR PUMPING AND DOSING A FLUID FOR A TURBOMACHINE AND METHOD FOR CONTROLLING SUCH A SYSTEM

Abstract

The invention proposes a system for pumping and metering (400) a fluid (10) for a turbomachine comprising at least one fluid pump (412, 414) and an electronic computer (430) configured to determine the flow rate of the fluid to be distributed to the turbomachine, the pumping and metering system being characterized in that it comprises a first electric motor and a second electric motor, each configured to drive the at least one pump and in that the electronic computer comprises a first control loop (432) intended to control at least the first electric motor and a second control loop (434) intended to control at least the second electric motor. Figure for the abstract: Figure 4

Description

Title of the invention: SYSTEM FOR PUMPING AND DOSING A FLUID FOR A TURBOMACHINE AND METHOD FOR CONTROLLING SUCH A SYSTEM Technical field of the invention

[0001] The present invention relates to a system for pumping and metering a fluid for a turbomachine, a turbomachine comprising it and a method for controlling such a system. Technical background

[0002] In the aeronautical field, turbomachines comprise numerous fluid pumping members, for example a main pumping member of a fuel circuit of a turbomachine, a low-pressure pumping member of a fuel circuit of a turbomachine or a pumping member of an oil circuit of a turbomachine. These fluid circuits require generation of hydraulic power and possibly the metering of the fluid flow rate.

[0003] In general, the generation of main hydraulic power is carried out by means of one or more pumps (so-called high-pressure pump(s)) mechanically driven via the gas generator of the turbomachine. The proper operation of the high-pressure pump(s) may require generation of auxiliary hydraulic power upstream which may be carried out by means of one or more pumps (so-called low-pressure pump(s) or "engine booster pump" in English) also mechanically driven via the gas generator of the turbomachine. The fuel metering, downstream of the high-pressure pumps, is generally carried out by a hydraulic device controlled by an electronic controller.

[0004] Nevertheless, mechanically driven pumps have many disadvantages. Indeed, the pump(s) is(are) sized for the worst operating case, for example aged pump, worst flight envelope conditions, worst fluid temperature, etc. Thus, the hydraulic power delivered by the pump(s) is generally greater than the current requirement of the turbomachine, resulting in an unnecessary withdrawal of mechanical power from the gas generator and an increase in the fluid temperature.

[0005] Furthermore, the mass of the mechanical drive (drive pinions and reducer housings) and of the hydraulic components or organs themselves (pumps, metering valves, pressure regulator) is significant.

[0006] In addition, the entire fluid metering device required to ensure the metering precision required by the regulation is very complex.

[0007] Furthermore, in the fuel circuits of existing aeronautical propulsion turbomachines, such as a helicopter turboshaft, turbofan or aircraft turboprop, the control and actuation members are generally redundant unlike the hydromechanical metering members (differential pressure regulator, valve). In this case, a blockage of the metering system results in a loss of operability of the turbomachine.

[0008] However, the elimination of the mechanical drive of the oil and fuel pumps is an essential step towards the total elimination of the accessory gearbox of the turbomachines, allowing in particular a gain in mechanical power extraction from the gas generator.

[0009] Thus, in certain applications, the turbomachine uses a high-pressure main pump, also called a metering pump, comprising an electric motor to drive it, which ensures both the main generation of hydraulic power and the metering of the fuel flow. On the other hand, these metering pumps, also called "motor pumps", are simplex components, that is to say that a failure of the motor pump causes the fuel supply or lubrication of the turbomachine to stop, leading to an engine shutdown in flight.

[0010] The present invention aims to remedy at least some of these drawbacks. Summary of the invention

[0011] The invention proposes a system for pumping and metering a fluid for a turbomachine comprising at least one fluid pump and an electronic computer configured to determine the flow rate of the fluid to be distributed to the turbomachine, the pumping and metering system being characterized in that it comprises a first electric motor and a second electric motor, each configured to drive the at least one pump and in that the electronic computer comprises a first regulation loop intended to control at least the first electric motor and a second regulation loop intended to control at least the second electric motor.

[0012] Thus, the invention provides an alternative to mechanically driven fluid metering and pressurization systems offering the same level of safety as the latter.

[0013] Furthermore, the invention allows a weight saving for the pumping and dosing system.

[0014] The system for pumping and metering a fluid according to the invention may comprise one or more of the following characteristics, taken in isolation from one another or in combination with one another:

[0015]

[0016]

[0017]

[0018]

[0019] - the fluid pumping and metering system is configured to generate a flow of the fluid, the fluid being fuel or lubricating oil; - the fluid pumping and metering system is configured to pressurize the fluid, the fluid being fuel intended to supply a main metering system of the turbomachine; - the first electric motor and the second electric motor are each configured to drive the same pump; - the fluid pumping and metering system comprises two pumps: a first pump configured to be driven by the first electric motor, and a second pump configured to be driven by the second electric motor; - the first pump and the second pump are arranged in parallel between a fluid reservoir and a component of the turbomachine to be supplied with fluid; - the system for pumping and metering a fluid comprises a first non-return device arranged upstream or downstream of the first pump and a second non-return device arranged upstream or downstream of the second pump; - the first pump and the second pump are arranged in series between a fluid reservoir and a component of the turbomachine to be supplied with fluid; - the system for pumping and metering a fluid comprises a first non-return device arranged in parallel with the first pump and a second non-return device arranged in parallel with the second pump. The present invention also relates to a turbomachine, characterized in that it comprises at least one system for pumping and metering a fluid according to the invention and as described previously. The present invention also relates to an aircraft comprising at least one such turbomachine. The present invention also relates to a method for controlling such a fluid pumping and metering system, a first control channel comprising a first acquisition unit, the first regulation loop of the electronic computer and at least the first electric motor and a second control channel comprising a second acquisition unit, the second regulation loop of the electronic computer and at least the second electric motor, the method being characterized in that it comprises the steps consisting of: a. authorize the first control channel comprising the first control loop to control the at least one pump via at least the first electric motor; b. establish a hydraulic power or flow rate setpoint for at least the electric motor of the first control channel authorized by the first control loop from data provided by at least the first acquisition unit of the first authorized control channel; and c. in the event of a failure of at least one element chosen from the list comprising the first acquisition unit, the first control loop and at least the first electric motor of the first authorized control channel and the at least one pump, transfer the authorization to control the at least one pump from the first control channel to the second control channel, and establish a hydraulic power or flow rate setpoint for at least the electric motor of the second control channel authorized by the second control loop from data provided by at least the second acquisition unit of the second authorized control channel.

[0020] The control method according to the invention may comprise one or more of the following characteristics, which may be taken in isolation from one another or in combination with one another:

[0021] - each control loop of a control channel is intended to control a single electric motor; - each control loop of a control channel is authorized to control the first and second electric motors; - establishing a flow rate or hydraulic power setpoint includes a step consisting of establishing a distribution of hydraulic power or flow rate to be supplied to the turbomachine between the two electric motors; - the flow or hydraulic power to be supplied is equally distributed between the two electric motors; - the first control loop and the second control loop are adapted to exchange data; - in the event of a failure of at least one element of the first authorized control channel among the first control loop, the first electric motor and the first pump, the flow rate or hydraulic power setpoint is applied in full to the second electric motor; - each control channel is adapted to control the first electric motor and the second electric motor, and the first control loop is configured to jointly control the first electric motor and the second electric motor according to the established flow rate or hydraulic power setpoint except in the event of failure of at least one element of the first authorized control channel; - in the event of failure of at least one element of the first control channel among the first control loop and the first acquisition unit, the second control loop is connected and configured to jointly control the first electric motor and the second electric motor according to a flow or power setpoint established by the second control loop of the second control channel to which the authorization is transferred; - the fluid pumping and metering system comprises two pumps: a first pump configured to be driven by the first electric motor, and a second pump configured to be driven by the second electric motor, and in which in the event of a failure of a pump or of the first electric motor, the flow rate or hydraulic power setpoint is such that the other pump connected to the second electric motor provides the entire flow rate or hydraulic power to the turbomachine; - the control process includes a preliminary step during which, when the turbomachine is started and until an idle speed is established, only one pump supplies all the power to the turbomachine; - the control process includes a step of alternating the pump providing all of the power required at each start of the turbomachine; - the flow or power distribution is established according to at least one factor among the operating point of the turbomachine, the state of health of each control loop of the computer, the state of health of each motor pump, the margin at extinction or pumping, the current acceleration / deceleration, the power supplied by the turbomachine, the flight conditions; - the control process includes a step of monitoring the efficiency of the electric motors and the pump(s); - the fluid is fuel or lubricating oil. Brief description of the figures

[0022] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the appended drawings in which:

[0023] [Fig-1] [Fig.l] is a schematic view of a pumping and dosing system of a fluid according to a first embodiment of the invention;

[0024] [Fig.2] [Fig.2] is a schematic view of a pumping and dosing system of a fluid according to a second embodiment of the invention;

[0025] [Fig.3] [Fig.3] is a schematic view of a system for pumping and metering a fluid according to a third embodiment of the invention;

[0026] [Fig.4] [Fig.4] illustrates a generalization of a system for pumping and metering a fluid according to the invention adapted to implement a control method according to the invention;

[0027] [Fig.5] [Fig.5] is a block diagram illustrating steps of an embodiment of a method for controlling a system for pumping and metering a fluid according to the invention;

[0028] [Fig.6A] [Fig.6A] illustrates a control method according to a first embodiment of the invention in normal operation;

[0029] [Fig.6B] [Fig.6B] illustrates the control method according to the first embodiment of the invention in the event of a failure of a computer channel;

[0030] [Fig.6C] [Fig.6C] illustrates the control method according to the first embodiment of the invention in the event of a sensor failure;

[0031] [Fig.6D] [Fig.6D] illustrates the control method according to the first embodiment of the invention in the event of a breakdown of a motor pump;

[0032] [Fig.7A] [Fig.7A] illustrates a control method according to a second embodiment of the invention in normal operation;

[0033] [Fig.7B] [Fig.7B] illustrates the control method according to the second embodiment of the invention in the event of a failure of a computer channel;

[0034] [Fig.7C] [Fig.7C] illustrates the control method according to the second embodiment of the invention in the event of a sensor failure;

[0035] [Fig.7D] [Fig.7D] illustrates the control method according to the second embodiment of the invention in the event of a motor pump breaking down;

[0036] [Fig.8A] [Fig.8A] illustrates a piloting method according to a third mode of rea use of the invention in normal operation;

[0037] [Fig.8B] [Fig.8B] illustrates the control method according to the third embodiment of the invention in the event of a failure of a computer channel;

[0038] [Fig.8C] [Fig.8C] illustrates the control method according to the third embodiment of the invention in the event of a sensor failure;

[0039] [Fig.8D] [Fig.8D] illustrates the control method according to the third embodiment of the invention in the event of a breakdown of a motor pump;

[0040] [Fig.9] [Fig.9] illustrates an example of a motor pump load law applicable to the control methods of figures 7 and 8 in “fully operational” operating mode;

[0041] [Fig. 10] [Fig. 10] illustrates an example of a motor pump load law applicable to the control methods of Figures 7 and 8 in the event of a breakdown of one of the motor pumps;

[0042] [Fig. 11] [Fig. 11] illustrates another example of a load law for motor pumps as a function of the operating phase of the turbomachine for the control methods of figures 7 and 8;

[0043] [Fig. 12] [Fig. 12] illustrates another example of the load law of the motor pumps between the start-up and the idling of the turbomachine for the control methods of figures 7 and 8;

[0044] [Fig. 13] [Fig. 13] illustrates an example of a load law for motor pumps for the control methods of Figures 7 and 8 in the particular case where there is an emergency power regime.

[0045] In the various figures, similar elements are designated by identical references. Furthermore, the various elements are not necessarily represented to scale in order to present a view making it easier to understand the invention.

[0046] By convention, in the present application, the terms “upstream” and “downstream” are defined in relation to the direction of circulation of the fluid in a pump. Detailed description of the invention

[0047] Although the example described relates to a fuel pumping and metering system configured to generate a fuel flow, it is clear that this example is not limiting and that the invention also applies to any other system for generating hydraulic power of an aeronautical fluid, requiring more or less control precision. For example, the invention could be applied to a fuel booster pressure generation system located upstream of a main hydraulic power generation system, or to an oil flow generation system used for the lubrication or cooling of turbomachines.

[0048] The invention proposes a system for pumping and metering a fluid, in particular for a turbomachine, comprising at least one hydraulic fluid pump configured to be driven by at least one electric motor and to be controlled by a multi-channel electronic computer.

[0049] Preferably, the pumping and dosing system according to the invention comprises one or two pumps and a two-channel electronic computer for controlling the electric motors driving the pump(s).

[0050] The or each hydraulic pump may be, for example, a centrifugal pump or a positive displacement pump, for example of the gear, vane or gerotor type, or any other pump technology for generating hydraulic power.

[0051] Each electric motor is powered by an electrical power source not shown in Figures 1 to 4.

[0052] Furthermore, an electric motor can be integrated into a hydraulic pump. Such an assembly is known as a motor pump.

[0053] The electronic calculator includes regulation loops independent of each other, providing a control or piloting instruction to each motor. electrical system of the pumping and dosing system.

[0054] Preferably, each control loop establishes its control setpoint from data provided by a set of respective sensors.

[0055] In the case of advanced pumps, integrating electronics and sensors for example for fluid speed or temperature, this data can also be transmitted to the electronic computer, by an ad hoc communication interface, for example a digital link, for inclusion in the control loops.

[0056] Two control / piloting channels for the hydraulic pumps are thus established, making it possible to implement redundant electronic control capable of meeting the imposed safety requirements. Each control channel includes a set of sensors providing input data, a control loop of the electronic computer, an electric motor up to a hydraulic pump.

[0057] [Fig.l] illustrates a first dosing and pressurization system 100 of a fluid 10 according to a first embodiment of the invention, with a single pump.

[0058] The pumping and metering system 100 comprises a hydraulic fluid pump 112 and two electric motors 122, 124, each configured to drive the pump 112.

[0059] In the illustrated example, the two electric motors are arranged on either side of the hydraulic pump 112. In this case, each electric motor is kinetically connected to the hydraulic pump, for example by means of a freewheel.

[0060] In a variant not shown, the two electric motors are arranged on the same side of the hydraulic pump and advantageously have common mechanical parts, such as for example a rotor or nested stators. Such an arrangement advantageously makes it possible to save mass and volume.

[0061] The pumping and dosing system 100 further comprises an electronic computer 130 for controlling the electric motors controlling the pump.

[0062] The electronic calculator 130 comprises a first regulation loop 132 providing a control command or instruction M1 to the first electric motor 122 and a second independent regulation loop 134, providing a control command M2 to the second electric motor 124.

[0063] Preferably, each control loop 132, 134 establishes its control setpoint from data provided by a set of respective sensors 142, 144.

[0064] Two control / piloting channels for the hydraulic pump 112 are thus established, making it possible to implement redundant electronic control capable of meeting the imposed safety requirements. The first control channel 152 includes the set of sensors 142 providing input data, the control loop 132, the first electric motor 122 up to the distribution pump 112. Similarly, the second control channel 154 includes the set of sensors 144 providing input data. input data, the control loop 134, the electric motor 124 up to the distribution pump 112.

[0065] Thus, in the event of a breakdown occurring on an element of a regulation channel, for example the electric motor, a sensor or the regulation loop of the computer, the electric motor of the other regulation channel is capable of driving the pump.

[0066] In this architecture, only the portion of the regulation path upstream of the pump is redundant; a single pump ensures the generation of hydraulic power.

[0067] [Fig.2] illustrates a second embodiment of a pumping and metering system 200 according to the invention, with two hydraulic pumps 212, 214 mounted in parallel between a fluid reservoir (fluid inlet) and a member of the turbomachine to be supplied with fluid, each pump being driven by a dedicated electric motor, 222, 224.

[0068] For each pump 212, 222, a flow non-return device 226, 228 is preferably arranged upstream or downstream (relative to the circulation of the fluid), for example a non-return valve or any other member making it possible to perform this function. These flow non-return devices 226, 228 make it possible to avoid a loss of flow through a pump when the latter is broken down or stopped.

[0069] As seen previously, when the pumps integrate electronics, measurement data can be transmitted to the electronic computer via respective communication links.

[0070] In this architecture, the entire control chain is redundant: each control channel including its set of sensors, its regulation loop (from the computer not shown), its electric motor and its pump (and its digital link where applicable).

[0071] [Fig. 3] illustrates a third embodiment. The pumping and metering system 300 comprises, like the second embodiment, two hydraulic pumps 312, 314 but arranged in series between the fluid reservoir and the member to be supplied, each pump being driven by a respective electric motor, 322, 324.

[0072] Advantageously, two flow non-return devices 326, 328 are provided, such as for example a non-return valve or any other member making it possible to perform this function. Each flow non-return device 326, 328 is arranged in parallel on a respective pump, the two valves being arranged in series between the fluid reservoir and the member to be supplied. These flow non-return devices 326, 328 make it possible to compensate for any flow differences between the two pumps, or to ensure a preferred path for the fluid in the event of one of the pumps stopping (bypass).

[0073] The described architectures of a pumping and dosing system according to the invention allow the implementation of an improved control method, integrating fault management satisfying the safety criteria imposed in the vehicles of the aeronautical field....

[0074] The method will now be explained, with reference to [Fig.4], which illustrates the general case of a pumping and metering system according to the invention comprising two electric motors for controlling the distribution of fluid to the member to be supplied, in particular by controlling the fluid flow rate. In the case where each motor drives its own pump, the motor+pump assembly is designated by the term motor pump. In the following, to simplify the description, we will use this configuration with two motor pumps.

[0075] The pumping and metering system 400 therefore comprises two motor pumps 412, 414. Each motor pump, 412, 414, corresponds to a specific control loop 432, 434 of an electronic computer, 430, each control loop receiving specific data from an acquisition unit, 442, 444, to establish a power setpoint for the associated motor pump, 412, 414. The data are those provided by one or more external sensors, and / or by each pump, when the pumps integrate corresponding electronics.

[0076] The electronic computer 430 is configured to determine the flow rate of the fluid to be distributed by each motor pump from the data acquired by these acquisition units 442, 444, in each of the two regulation loops.

[0077] Such an architecture defines two control channels 452, 454, each having its acquisition unit, 442, 444, its regulation loop 432, 434 of the computer and its motor pump 412, 414.

[0078] [Fig. 5] illustrates the steps of a method 500 for controlling the pumping and dosing system 400 of [Fig. 4], in which each control loop 432, 434 is intended to control at least one electric motor or motor pump 412, 414.

[0079] The method 500 comprises at least the following steps:

[0080] - During a step 502, authorize a control channel among the first control channel 452 and the second control channel 454 to control at least one of the motor pumps 412, 414. In other words, this control channel has “full authority”, it is the only control channel which can establish flow rate or hydraulic power setpoints in order to control the motor pump(s) 412, 414 during operation of the turbomachine. Subsequently, the control loop having authority will be called the control loop of the control channel having full authority.

[0081] Subsequently, the first control channel 452 is arbitrarily chosen as the channel having authority or control channel.

[0082] - Reception by the first regulation loop 432 of the electronic computer 430 of acquisition data from at least the acquisition unit of the authorized control channel, here the first acquisition unit 442, during of a step referenced 504. - During a step 506, the regulation loop of the authorized control channel, here the first regulation loop 432, determines, from the acquisition data received, the flow rate of the fluid or the hydraulic power to be supplied to the turbomachine by at least the motor pump of the authorized control channel. - The first control loop 432 then establishes, during a step 508, a flow rate or hydraulic power setpoint for at least the motor pump of the authorized control channel from the determined fluid flow rate or hydraulic power. - In the event of a failure of at least one element of the authorized control channel, i.e. the acquisition unit, the control loop, the electric motor or motor pump of the authorized control channel, the control authorization is transferred to the other control channel, here the second control channel 454, during a step referenced 510. Thus, the first control channel 452 no longer has the authority to control the motor pump(s). Only the second control channel 454 has “full authority” and can establish flow rate or hydraulic power setpoints in order to control the motor pump(s) 412, 414 during operation of the turbomachine.

[0083] Figures 6 to 8 illustrate three embodiments of this control method. More specifically, each figure 6 to 8 illustrates a decision matrix corresponding to an embodiment of the control method, these decision matrices illustrating normal operation of the control channel having authority and three different cases of failure which may occur in this control channel.

[0084] In the embodiment shown in Figure 6, grouping Figures 6A to 6D, each regulation loop 432, 434 is intended to control a single electric motor or motor pump 412, 414.

[0085] In the embodiment illustrated in Figure 7 (grouping Figures 7A to 7D), the control loops 432 and 434 of the computer advantageously communicate with each other via a so-called “interchannel” link 460 between the two control loops, allowing an exchange of data between the two control channels.

[0086] The embodiment of figure 8 (grouping figures 8A to 8D) corresponds to an improved control method in which each regulation loop 432, 434 is authorized to jointly and directly control the two motor pumps 412, 414 of the system.

[0087] In these figures, the elements of the pumping and dosing system shown in bold lines are operational and active, those in dotted lines are broken, the others are inactive or on standby. Thus the control channel having authority is the control channel piloting whose control loop is represented in bold line.

[0088] The three embodiments of the method will now be detailed.

[0089] Figures 6A to 6D illustrate a decision matrix of a first embodiment of the control method in which each regulation loop 432, 434 is intended to control a single electric motor or motor pump 412, 414.

[0090] [Fig.6A] represents the case of normal operation in which all the elements of the control channel are operational, that is to say all the elements of the first pilot channel 452 which in this illustrated example has authority.

[0091] The second control channel 454 is on standby. In practice, saying that the control channel 454 is on standby means that the output signal from the control loop 434 is not applied to the second motor pump 414, as shown schematically by a switch in the open position. In other words, the second control loop 434 does not have the authority to control the second motor pump 414.

[0092] In this case, the first motor pump 412 provides the entire flow rate or hydraulic power required by the turbomachine, based on the power or flow rate setpoint established by the first control loop 432 of the control channel which has authority.

[0093] In the event of a failure in the channel under control, i.e. the control channel which has authority (regulation loop in bold in the figures), whether it is a failure of the regulation loop 432 ([Fig.ôB]), of the acquisition unit 442 or of one of its essential sensors ([Fig.ôC]) or of the motor pump 412 (motor and / or pump) ([Fig.ôD]) of the channel under control: there is switching of the control channels in standby and in control. Thus, the control authorization is transferred from the first control channel 452 to the second control channel 454. The first control channel 452 is then in standby as is shown diagrammatically by a switch in the open position at the output of the first regulation loop 432 while the switch at the output of the second regulation loop 434 is in the closed position.

[0094] The second control channel 454 has full authority to control the second motor pump 414 by establishing a flow rate or hydraulic power setpoint from the data transmitted by the second acquisition unit 444. The second control loop 434 controls the motor pump 414 which then provides all of the hydraulic power required for the operation of the turbomachine.

[0095] In practice, this step of transferring authority or switching the control channel in the event of a failure of an element of the control channel having authority can result in a non-negligible transient regime, due to the time required for the second motor pump 414 to take over all of the power load previously carried out by the first motor pump 412.

[0096] Nevertheless, this process responds to a philosophy of piloting and therefore of management of failures of current aeronautical turbomachines in a control channel having a regulation loop having control authority only over a single motor pump.

[0097] Figures 7A to 7D represent a decision matrix corresponding to a second embodiment of the control method of [Fig.5], advantageously making it possible to reduce the duration of the transient regime. This second embodiment is particularly suitable for pumping and metering systems in which the two control loops 432, 434 of the electronic computer 430 are adapted to exchange data via a so-called “interchannel” link 460. For example, the data exchanged are measurements or diagnostic data provided by the acquisition units 442, 444 or else a setpoint established by a control loop of the control channel in control to control the motor pump of the other control channel.

[0098] According to this embodiment of the method, during step 504 ([Fig.5]) the control channel having authority (i.e. the first control channel 452) receives data from both the first acquisition unit 442 and the second acquisition unit 444. Then the control loop 432 of the first control channel 452 (having authority) determines from this data the flow rate of the fluid or the hydraulic power to be supplied to the turbomachine by each of the motor pumps 412, 414 (step 506 of [Fig.5]) and establishes a flow rate or hydraulic power setpoint for each motor pump 412, 414 in order to be able to control them simultaneously for the operation of the turbomachine (step 508 of [Fig.5]).In other words, the control loop 432 of the first control channel 452 (having authority) determines a distribution of the flow rates or hydraulic powers to be supplied to the turbomachine by each electric motor or motor pump 412, 414, in particular from the data exchanged between the two control loops via the interchannel link 460.

[0099] The second control loop 434, of the standby control channel 454, can in this case be authorized to control the second motor pump 414, with limited authority, to provide a portion of the flow rate or hydraulic power required by the turbomachine. By limited authority, it is meant that the second control loop 434, of the standby control channel 454, controls the second motor pump 414 from the setpoint established by the first control loop 432 of the first control channel 452 (having full authority). The second control loop 434, of the standby control channel 454 does not establish the setpoint to control the second motor pump 414, it receives it from the first control loop 432.

[0100] This embodiment of the method advantageously makes it possible to reduce the duration of the transient regime in the event of a transfer of authority or channel switching.

[0101] In the situation of [Fig.7A] (normal case), the control channel having authority is the first control channel 452 (shown in bold) which determines the total flow rate or total hydraulic power required by the turbomachine and distributes it between the two active motor pumps 412, 414. The second control loop 434 of the second control channel 454 is on standby, with "limited authority", to transmit the flow rate or hydraulic power setpoint established by the first control loop 432 to the second motor pump 414 in order to control it.

[0102] In the event of a failure in the control channel 452, of the first regulation loop 432 or of the first associated motor pump 412, as illustrated in FIGS. 7B and 7D by dotted lines, the control authority and consequently the establishment of the flow rate or hydraulic power setpoints are transferred from the first regulation loop 432 to the second regulation loop 434, which becomes the regulation loop of the control channel having authority.

[0103] In this case, only the second motor pump 414 remains active and provides all of the flow rate or hydraulic power required for the operation of the turbomachine, the second control loop 434 (“having authority”) establishes a setpoint in this sense. As the second motor pump 414 was already in operation or “on load”, it sees a less pronounced transient regime than for the first embodiment of the control method of FIGS. 6A to 6D.

[0104] In the event of failure of the first acquisition unit 442 (shown schematically in dotted lines) of the control channel 452 having authority ([Fig.7C]), that is to say upstream of the control loop 432, there is also a transfer of the control authority from the first control channel 452 to the second control channel 454. Thus, the second control loop 434 of the channel in control determines the total flow rate or total hydraulic power required by the turbomachine and distributes it between the two active motor pumps 412, 414. The first control loop 432 of the first control channel 452 is then on standby, with "limited authority", to transmit the setpoint in flow rate or hydraulic power established by the second control loop 434 to the first motor pump 412 in order to control it. Each control loop continues to control the motor pump associated with it.

[0105] Figures 8A to 8D represent a decision or control matrix corresponding to a third improved embodiment of the control method of [Fig. 5]. This third embodiment of the method is particularly suitable for pumping and metering systems in which each control loop 432, 434 is electrically connected to the two motor pumps 412, 414 and is able to jointly control the two motor pumps 412, 414 of the pumping and metering system. The two control loops 432, 434 of the electronic computer 430 can also be adapted to exchange data via a so-called “interchannel” link 460.

[0106] With reference to [Fig.8A] relating to the normal operating case, the control channel having authority (shown in bold lines) is the first control channel 452 whose control loop 432 is connected to the two motor pumps 412, 414.

[0107] During step 506 ([Fig.5]), the first control loop 432 determines the flow rate of the fluid or the hydraulic power to be supplied to the turbomachine by each of the motor pumps 412, 414 from data from at least the first acquisition unit 442. In other words, the control loop 432 of the first control channel 452 (having authority) determines a distribution of the flow rates or hydraulic powers to be supplied to the turbomachine by each electric motor or motor pump 412, 414. Then, it establishes a flow rate or hydraulic power setpoint for each motor pump 412, 414 in order to be able to control them directly and simultaneously for the operation of the turbomachine (step 508 of [Fig.5]).

[0108] During this time, the second regulation loop 434 of the standby channel 454 does not establish any control instructions for the motor pumps and does not control any of the motor pumps as shown diagrammatically by the switches in the open position connected respectively to the first motor pump 412 and to the second motor pump 414 at the output of the second regulation loop 434.

[0109] In the event of a failure in the control channel having authority 452 of at least one element upstream of the motor pump, i.e. of the control loop 432 ([Fig.8B]) and / or of the acquisition unit 442 ([Fig.8C]), the control authority and consequently the establishment of the flow rate or hydraulic power setpoints are transferred from the first control loop 432 to the second control loop 434, which becomes the control loop of the control channel having authority. This is shown diagrammatically by the passage of the switches connected respectively to the motor pumps 412, 414 at the output of the first control loop 432 from the closed position to the open position.

[0110] Thus, the regulation loop 434 of the second control channel 454 (having authority) determines a distribution of the flow rates or hydraulic powers to be supplied to the turbomachine by each electric motor or motor pump 412, 414. Then, it establishes a flow rate or hydraulic power setpoint for each motor pump 412, 414 in order to be able to control them directly and simultaneously for the operation of the turbomachine.

[0111] Starting from one of these situations of figures 8B or 8C, and in the event of a breakdown of one of the motor pumps (in the case illustrated in [Fig.8D], the first motor pump 412 is broken), the second regulation loop 434 of the control channel has authority (control channel 454) is able to establish a setpoint in flow rate or hydraulic power to control the second motor pump 414, the only functional motor pump, so that it provides the entire flow rate or hydraulic power necessary for the operation of the turbomachine.

[0112] Similarly, if it is the second motor pump 414 which is faulty, the loop regulation 434 is also capable of establishing a flow rate or hydraulic power setpoint to control the first motor pump 412, the only functional motor pump, so that it provides all of the flow rate or hydraulic power necessary for the operation of the turbomachine.

[0113] This also applies from the situation of the case illustrated in [Fig.8A], in which the first control channel 452 has authority: if one of the motor pumps has a fault, the first regulation loop 432 of the control channel having authority is able to establish a setpoint in flow rate or hydraulic power to control the other of the motor pumps still functional, so that the latter provides the entire flow rate or hydraulic power necessary for the operation of the turbomachine.

[0114] As in the case of the second embodiment of the method, the transient regime is improved since the still functional motor pump(s) were already in operation.

[0115] Figures 9 and 10 illustrate load laws of the two motor pumps corresponding to the decision matrices of the second and third embodiments of the control method described above (Figures 7 and 8) in the case of an equitable distribution of the powers between the two motor pumps: [Fig. 9] for a “fully operational” operating mode and [Fig. 10], in the event of a breakdown of one of the motor pumps.Thus, figures 9 and 10 each represent by a graph the evolution of the flow rate or total hydraulic power (curve referenced CIO) available for the turbomachine, the evolution of the flow rate or hydraulic power of the first motor pump (curves referenced C12, C22), the evolution of the flow rate or hydraulic power of the second motor pump (curves referenced C14, C24) and the evolution of the nominal flow rate or nominal hydraulic power for each motor pump (curve referenced Cl6) as a function of the power of the turbomachine, from start-up to the maximum power of the turbomachine.

[0116] In [Fig.9], the distribution of hydraulic power or flow rate to be supplied being equitable between the two motor pumps 412, 414, these follow the same load law from the start of the turbine to the maximum operating power of the turbomachine when everything is operational.

[0117] With regard to [Fig. 10], when one of the motor pumps, here the second motor pump 414, fails after the turbine start-up phase, the flow rate or hydraulic power supplied by the second motor pump becomes zero (curve referenced C24) while the other motor pump 412 takes over and then supplies the entire flow rate or hydraulic power required for the operation of the turbomachine (curve referenced C24). Each motor pump is then sized to be able to supply the entire power required by the turbomachine.

[0118] Whether for the second or for the third embodiment of the control method, the distribution of flow rate or hydraulic power to be provided by the two motor pumps can be equal or arbitrary. For example, one motor pump can provide the power corresponding to the anti-extinction flow rate of the turbomachine and the other the complement.

[0119] The flow distribution can be established as a function of the operating point of the turbomachine, the health status of each regulation loop of the electronic computer, the health status of each motor pump, the margin for extinction or pumping, the current acceleration / deceleration, the power supplied by the turbomachine, the flight conditions or even a combination of all these factors.

[0120] [Fig. 11] represents by a graph the evolution of the total hydraulic flow or power (curve referenced CIO) available for the turbomachine, the evolution of the hydraulic flow or power of the first motor pump (curve referenced C32), the evolution of the hydraulic flow or power of the second motor pump (curve referenced C34) as a function of the power of the turbomachine, from start-up to the maximum power of the turbomachine when everything is operational and in the case of a static distribution, depending only on the power of the turbomachine. In this example, the power supplied by the second motor pump (curve referenced C34) corresponds from the idling of the turbomachine to the anti-extinction hydraulic flow or power of the turbomachine and the first motor pump provides the additional hydraulic flow or power (curve referenced C34).It is understood that the distribution may depend on the static or dynamic conditions of the operating point mentioned above.

[0121] In the case of an unequal distribution of flow rate or hydraulic power between the motor pumps, that is to say that one of the so-called preferred motor pumps provides a greater flow rate or power than the other motor pump, the control method according to the invention advantageously comprises a step of alternating the so-called preferred pump at each start-up of the turbomachine in order to standardize the wear of the two motor pumps.

[0122] Furthermore, during the start-up of the turbomachine, the fuel flow rate required by the combustion chamber is very low compared to the flow rates required in flight. Nevertheless, it requires good metering precision to enable the combustion chamber to be ignited under good conditions.

[0123] Furthermore, driving an electric motor can be tricky at low load. In addition, the accuracy of a low-power pump is difficult to ensure and requires tight manufacturing tolerances, matching, or costly adjustments.

[0124] To overcome these drawbacks and thus enable more easily achievable precision in dosing and pressurization, the control method according to the invention includes a preliminary step during which, when the turbomachine is started and until an idle speed is established, only one of the motor pumps provides the entire flow rate or power required by the turbomachine as illustrated in [Fig. 12] which represents by a graph the evolution of the total hydraulic flow rate or power (curve referenced CIO) available for the turbomachine, the evolution of the hydraulic flow rate or power of the first motor pump (curve referenced C42), the evolution of the hydraulic flow rate or power of the second motor pump (curve referenced C44) as a function of the power of the turbomachine, from start-up to maximum power of the turbomachine when everything is operational and only the first motor pump (curve referenced C42) provides the entire flow rate or power required by the turbomachine from start-up to idle of the turbomachine.In this preliminary step, it is advantageous to alternate the motor pump used at each start of the turbomachine in order to standardize the wear of the two motor pumps and / or to detect any deterioration of a motor pump.

[0125] Furthermore, a start attempt may fail for various reasons. The start failure may be due to conditions exogenous to the metering and pressurization system, such as a fault in the ignition system (spark plugs) of the combustion chamber or a failure of a fuel distribution valve; or to endogenous conditions, i.e. the motor pump used is actually failing to follow the flow rate setpoint.

[0126] In this case, the control method according to the invention advantageously comprises a so-called “second chance start” step. Thus, when the computer detects a failed start, it cuts off the start accessories (starter, starter solenoid valve and igniters), waits for the speed of the gas generator to decrease sufficiently, then makes a second start attempt with the other motor pump, all automatically. If in fact the second start attempt succeeds with this other motor pump, this may be a sign of a clear failure or a warning sign of degradation of the first motor pump. It is then advantageous to provide for recording corresponding information, as data useful for maintenance.

[0127] As indicated previously during the description of different embodiments of a control method according to the invention, each motor pump can be required to provide the entire power required by the turbomachine and in particular the maximum power required by the turbomachine, the two pumps and their electric motors are therefore sized accordingly.

[0128] In the particular case of application of the invention to a twin-turbine helicopter, i.e. comprising two motor pumps per turbine, i.e. four motor pumps in total, the sizing of the motor pumps must take into account the speed of emergency power, known as OEI mode for "One Engine Inoperative" in English. This OEI mode is used when one turbine is out of service; the other, operational turbine, must provide additional power until the end of the mission. The maximum power of the motor pumps must therefore be increased accordingly, which increases their mass and cost.

[0129] In order to limit the increase in cost and mass, each motor pump of the pumping and metering system according to the invention is sized to provide only the maximum between:

[0130] - the maximum flow rate or power required in the configuration where both turbines are operational (AEO regime for “Ail Engines Operative” in English), - half of the maximum OEI flow or power required in the event of loss of flow / power or failure of the other turbine,

[0131] the distribution of power or flow being carried out between the two motor pumps by making the likely assumption that the combination of the events “loss of power of a turbine leading to the need for an OEI regime on the other turbine” AND jointly “loss of a motor pump” is highly improbable. An example of a load law of the motor pumps of a corresponding turbine is illustrated in [Fig.13].

[0132] Advantageously, the control method according to the invention further comprises a step of monitoring the efficiency of the motor pumps by comparing the power of the electric motor with the rotation speed of the pump to which it is coupled and the power and / or speed of the motor pump with the power of the turbine. This step makes it possible to monitor the state of health of each motor pump.

[0133] Preferably, this monitoring step is carried out for the same pump at a given speed or during turbine start-up, at low flow rate.

[0134] The diagnosis concerning the state of health of the pump can advantageously be carried out by comparing the efficiency of the two pumps on similar speeds or between each start, if there is an alternation of the motor pumps on start-up.

[0135] The three embodiments of a control method according to the invention as described previously can be advantageously implemented by a system for pumping and metering a fluid as described previously and in particular for the second and third embodiments illustrated in Figures 2 and 3.

[0136] The second and third embodiments (figures 7 and 8) of the control method also allow sharing of flow rate or hydraulic power between the motor pumps, with the advantageous technical effects of allowing optimization of the sizing of the motor pumps, improving their aging and their response time in the event of failure of an element of the control channel having authority.

Claims

Claims

1. Pumping and metering system (300; 400) of a fluid (10) for a turbomachine comprising a first and a second pump (312, 314; 412, 414) of the fluid and an electronic computer (130;430) configured to determine the flow rate of the fluid to be distributed to the turbomachine, the pumping and metering system being characterized in that it comprises a first electric motor (322) configured to drive the first pump (312) and a second electric motor (324) configured to drive the second pump (314), each configured to drive the at least one pump and in that the electronic computer comprises a first control loop (432) intended to control at least the first electric motor and a second control loop (434) intended to control at least the second electric motor, and in which the first pump (312) and the second pump (314) are arranged in series between a fluid reservoir and a member of the turbomachine to be supplied with fluid.;

2. A fluid pumping and metering system according to the preceding claim, configured to generate a flow rate of the fluid, the fluid being fuel or lubricating oil.

3. A system for pumping and metering a fluid according to the preceding claim, configured to pressurize the fluid, the fluid being fuel intended to supply a main metering system of the turbomachine.

4. A fluid pumping and metering system according to one of the preceding claims, comprising a first non-return device (326) arranged in parallel with the first pump (312) and a second non-return device (328) arranged in parallel with the second pump (314).

5. Turbomachine, characterized in that it comprises at least one system for pumping and metering a fluid according to one of the preceding claims.

6. Aircraft comprising at least one turbomachine according to claim

7. J. Method for controlling a fluid pumping and metering system according to one of claims 1 to 4, a first control channel (452) comprising a first acquisition unit (442), the first regulation loop (432) of the electronic computer (430) and at least the first electric motor (412) and a second control channel (454) comprising a second acquisition unit (444), the second regulation loop (434) of the electronic computer (430) and at least the second electric motor (414), the method being characterized in that it comprises the steps consisting of: a. authorize (502) the first control channel (452) comprising the first control loop (432) to control the at least one pump via at least the first electric motor (412); b. establishing (508) a hydraulic power or flow rate setpoint for at least the electric motor (412) of the first control channel (452) authorized by the first control loop (432) from data provided by at least the first acquisition unit (442) of the first authorized control channel (452); and c. in the event of a failure of at least one element chosen from the list comprising the first acquisition unit (442), the first control loop (432) and at least the first electric motor (412) of the first authorized control channel and the at least one pump, transferring the authorization to control the at least one pump from the first control channel (452) to the second control channel (454), and establishing a hydraulic power or flow rate setpoint for at least the electric motor (414) of the second control channel (454) authorized by the second control loop (434) from data provided by at least the second acquisition unit (444) of the second authorized control channel (454).

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