Method for controlling a hybrid turbine engine with mechanical over-torque limitation, associated hybrid turbine engine and aircraft comprising such a turbine engine

Abstract

The invention relates to a method for controlling a hybrid turbine engine comprising a propulsion shaft, an electric machine, a mechanical transmission line between the shaft and the electric machine, provided with a radial transmission shaft capable of being subjected to a torsional resonance mode, a control device (DCE, DCEHP, DCEBP) of the electric machine, in accordance with the following steps: a) applying a torque command (CEEC, HP, CEEC, BP) at the electric machine via the control device of the electric machine; b) determining the angular velocity (W) of the electric machine; c) determining whether angular velocity oscillations (ΔW) of the electric machine around a zero centre are strictly greater than a threshold value (WSmin, WSmax) over a predetermined threshold duration (DS) and, if so: d) stopping applying the torque command for the electric machine.

Description

Description TITLE: Method for controlling a hybrid turbomachine with limitation of mechanical overtorque, associated hybrid turbomachine and aircraft comprising such a turbomachine. Technical field of the invention

[0001] The present invention relates to the field of hybrid turbomachinery for an aircraft. Technological background

[0002] Climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various states.

[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 consequences, with the aim of improving the energy efficiency of aircraft.

[0004] In this context, it is known to mount an electric machine on the propulsion shaft of an aircraft turbomachine, for example, a fan shaft, to obtain a hybrid turbomachine. Currently, the electric machine is configured either to operate in generator mode (drawing mechanical power from the propulsion shaft to generate electrical power) or configured to operate in motor mode (supplying mechanical power to the propulsion shaft by drawing electrical power, for example, from an electric battery).

[0005] The climate impact of hybrid turbomachinery is interesting.

[0006] With reference to Figure 1, the design of a hybrid T turbomachine with electrical assistance on the High Pressure shaft AHP and the Low Pressure shaft A is described in more detail. Bp. Thus, the MEHP electric machine (for example intended to operate in generator mode and in motor mode) is connected to the High Pressure AHP propulsion shaft of the turbomachine by a transmission line LTMHP comprising, starting from the High Pressure AHP shaft, an internal transmission box 21 known under its designation IGB (for "Internal Gear Box" according to Anglo-Saxon terminology), a radial transmission shaft 22 known under its designation RDS (for "Radial Drive Shaft" according to Anglo-Saxon terminology), an accessory relay box 23, known under its designation AGB (for "Accessory Gear Box" according to Anglo-Saxon terminology) which allows mechanical connection with several accessories.

[0007] The electrical machine is, for example, of the permanent magnet synchronous machine (PMSM) type.

[0008] The accessory relay box 23 allows the connection of various types of accessories, such as one or more electric machines. Currently, in most cases, a dedicated electric machine is used for generator operation (to generate electricity for the aircraft's needs), which can also be used in engine mode (for turbomachine starting) in certain applications. An air starter can be used if the electric machine does not perform the starting function.

[0009] The hybrid turbomachine T can also include an adapter box 24 to provide the mechanical interface between the electric machine 1 and the accessory relay box 23 (“AGB”). This adapter box 24 includes, in particular, gears R1, R2 to adapt the rotational speeds between the High Pressure shaft AHP of the turbomachine and the rotor of the electric machine ME.

[0010] Without going into detail, the MEBP electric machine is connected to the Low Pressure A shaft B p of propulsion of the turbomachine by an LTMBP transmission line.

[0011] It should be noted that, as an alternative, the turbomachine may provide for an electric machine on a single turbomachine shaft, for example only on the High Pressure shaft or on the single Low Pressure shaft or any other turbomachine shaft.

[0012] The electric machine is designed to operate in motor mode or generator mode. The electric machine applies either a negative torque (generator mode) to supply electrical power to aircraft loads and / or a turbomachine load by drawing mechanical power, or a positive torque (motor mode) to supply mechanical power to the turbomachine shaft.

[0013] The regulation of the electric machine is typically based on measuring the currents emanating from the electric machine (which equivalently allows for obtaining a controlled electromagnetic torque). It has been observed that this regulation allows for an accuracy of approximately 5 to 10% between the setpoint and the mechanical torque of the electric machine in steady-state operation, which can be considered sufficient in many cases.

[0014] Under certain operating conditions, the torsional mode of the radial transmission shaft 22 is excited (low frequencies), resulting in significant mechanical overtorques that translate into oscillations in the rotational speed of the electric machine's rotor. Under these same conditions, the measured electromagnetic torque remains almost equivalent to the received setpoint, and the excitation of the torsional mode is not visible in the measurement of the electric machine currents, which are regulated at high frequencies.

[0015] One objective of the invention is to propose a solution to improve regulation, by limiting or avoiding any mechanical overtorque linked to the excitation of the torsion mode of the radial transmission shaft. Summary of the invention

[0016] To this end, the invention proposes a method for controlling a hybrid turbomachine, said turbomachine comprising a drive shaft, at least one electric machine, a mechanical transmission line between the shaft and the electric machine, said mechanical transmission line comprising a radial drive shaft capable of undergoing a torsional resonance mode and a control device for the electric machine, the method comprising the following steps: a) apply a torque control at the level of the electrical machine via the electrical machine control device; b) determine the angular velocity of the electric machine; c) determine, using computer implementation, whether zero-centered angular velocity oscillations of the electric machine are strictly greater than a threshold value over a predetermined threshold time and, if so: d) stop applying the torque control for the electric machine.

[0017] Thus, thanks to the process according to the invention, any mechanical overtorque likely to damage the various mechanical parts is avoided.

[0018] The process according to the invention may comprise one or more of the steps below, taken individually or in combination with each other: - in step b), the angular velocity of the electric machine is measured; - in step b), the angular velocity of the electric machine is estimated; - the threshold value defined in step c) depends on the speed of the electric machine; - to determine, during step c), whether the zero-centered angular velocity oscillations of the electric machine are strictly greater than the threshold value over the predetermined threshold time, step c) of the process includes the following steps: Ci) supplying the angular velocity of the electric machine as input to a first processing line of a processing unit, said first processing line supplying zero-centered electric machine velocity oscillations as output;C2) provide the angular velocity of the electric machine as input to a second processing line of the processing unit, said second processing line providing as output two threshold values ​​of the velocity oscillations of the electric machine, a first threshold being defined for a negative torque value and a second threshold being defined for a positive torque value; and C3) compare, over the predetermined threshold time, the velocity oscillations obtained in substep C1) to one of the thresholds defined in substep C2) chosen according to the sign of the torque; - step Ci) includes the following sub-steps: filtering, with a low-pass filter, the angular velocity of the electrical machine; filtering, with a high-pass filter, the angular velocity filtered with the low-pass filter; these sub-steps allowing obtaining the velocity oscillations centered at zero; and optionally: taking the absolute value of the velocity oscillations previously obtained; - step Ci) includes the following sub-steps: filtering, with a high-pass filter, the angular velocity of the electrical machine; filtering, with a low-pass filter, the angular velocity filtered with the high-pass filter; these sub-steps allowing obtaining the oscillations of the velocity AW centered at zero; and optionally: taking the absolute value of the velocity oscillations previously obtained; - step Ci) includes the following sub-steps: filtering, with a bandpass filter, the angular velocity of the electrical machine, this sub-step allowing obtaining the velocity oscillations centered at zero; and optionally: taking the absolute value of the velocity oscillations previously obtained; - step C2) includes the following sub-steps: processing, in a first processing module (PM1), the angular velocity (W) of the electrical machine to obtain two threshold torques, a first threshold torque being defined for a negative torque value and a second threshold torque being defined for a positive torque value; optionally, taking the absolute value of the two threshold torques to define two corresponding threshold torques; and translating said threshold torques into threshold values ​​of the velocity oscillations; - the predetermined threshold duration implemented in step c) is at least 2ms, for example between 2ms and 10ms; - the torque control provided in step a) is derived from a power control divided by the angular velocity of the electric machine.

[0019] The invention relates to a hybrid turbomachine comprising: - a drive shaft, - an electrical machine, - a mechanical transmission line connecting the shaft to the electrical machine, said mechanical transmission line comprising a radial transmission shaft susceptible to undergoing torsional resonance, - an electrical machine control device comprising a means for determining the angular velocity of the electrical machine and a processing unit for determining whether angular velocity oscillations of the electrical machine centered at zero are strictly greater than a threshold value over a predetermined threshold time, said control device being configured to receive a torque command at the electrical machine and to stop this torque command when the velocity oscillations are strictly greater than the threshold value over the predetermined threshold time.

[0020] The invention also relates to an aircraft comprising a hybrid turbomachine as defined above. Brief description of the figures

[0021] The invention will be better understood with the aid of the following description, given solely by way of example and made with reference to the accompanying drawings in which : : - Figure 1, discussed previously, is a schematic representation of a hybrid Low Pressure BP and High Pressure HP turbomachine; - Figure 2 is a schematic representation of a method for controlling a hybrid turbomachine according to one embodiment of the invention; - Figure 3a is a diagram of an electrical machine control device that can be used to implement the process, the device including in particular a processing unit to process the angular speed of the electrical machine; - Figure 3b is an enlarged view of the control device of Figure 3a, at the level of a first processing line of the processing unit; - Figure 3c is an enlarged view of the control device of Figure 3a, at the level of a second processing line of the processing unit; - Figure 4 represents the evolution of the mechanical torque (top), in this case measured with a torque meter, as a function of time, and correspondingly, the angular velocity oscillations of the electric machine, in absolute value (bottom), by varying the torque setpoints over time; - Figure 5 represents the evolution of the mechanical torque (top), always measured by a torque meter, as a function of time, and correspondingly, the angular velocity oscillations (bottom) of the electric machine for a given torque setpoint; - Figure 6 represents the evolution of different torques (top: CEEC setpoint / control torque, C electromagnetic torque em and mechanical couple C m (which is always measured by a torque meter), as a function of time, and correspondingly, the angular velocity oscillations (at the bottom) of the electric machine; - Figure 7 is an enlarged view of Figure 6 from the top, on which we can also see the setpoint electromagnetic torque Cem, setpoint; - Figure 8 is a diagram of a variant of an electrical machine control device that can be used to implement the process, this device including means to ensure power regulation. Detailed description of the invention

[0022] Figure 1 is a diagram of a hybrid Low Pressure BP / High Pressure HP turbomachine.

[0023] The turbomachine includes an AHP shaft, A BThe propulsion system comprises two electric machines: a MEHP, MEBP, and a mechanical transmission line (LTMHP) between the AHP, ABP shaft and the MEHP, MEBP electric machine (the mechanical transmission line between the ABP low-pressure shaft and the MEBP electric machine is not shown in Figure 1). As noted, the turbomachine in this case includes two MEHP, MEBP electric machines: a first MEHP electric machine mounted on the high-pressure shaft (AHP) of the turbomachine and a second MEBP electric machine mounted on the low-pressure shaft (AHP). Bp of the turbomachine. The LTMHP mechanical transmission line includes a radial transmission shaft 22 that is susceptible to torsional resonance. The turbomachine also includes a DCE, DCEHP, and DCEBP control device for each electric machine. The control device translates a CEEC.HP or CEEC.BP torque command (or setpoint torque) onto the electric machine. Finally, the LTMHP mechanical transmission line includes an accessory relay box 23 and an adapter box 24 to interface between the electric machine and the accessory relay box 23.

[0024] Alternatively, it should be noted that the MEHP electric machine can only be installed on a high-pressure shaft (AHP) of the turbomachine. According to another alternative, the MEBP electric machine can only be installed on a low-pressure shaft (ABP) of the turbomachine. In yet another alternative, a machine can be installed on any other turbomachine shaft, such as an intermediate shaft in the case of a three-shaft turbine. More generally, the present invention is applicable to all hybridization architectures where at least one electric machine is mounted on a turbomachine shaft.

[0025] Figure 2 schematically represents the different stages of a control method for a hybrid turbomachine according to the invention.

[0026] The process includes the following steps: a) apply a torque control CEEC, CEEC.HP, CEEC.BP at the level of the electric machine ME, MEHP, MEBP via an electric machine control device DCE, DCEHP, DCEBP; b) determine an angular velocity W of the electric machine; c) Determine, using computer implementation, whether zero-centered angular velocity oscillations AW of the electric machine are strictly greater than a threshold value WSmin, WSmax over a threshold time period D s predetermined and, if so: d) stop applying the CEEC, CEEC.HP, CEEC.BP torque command for the electrical machine.

[0027] A more detailed description of the electrical machine control device is provided later, in support of Figure 3a.

[0028] In step b), we can measure or estimate the angular velocity W of the electric machine.

[0029] In step c), we can predict that the threshold value WSmin, WSmax depends on the angular velocity W determined in step b).

[0030] During step c), to determine if the zero-centered angular velocity oscillations AW of the electric machine are strictly greater than a threshold value WSmin, WSmax over a threshold time D s predetermined, step c) of the process includes the following steps: (Ci) provide the angular velocity W of the electric machine at the input of a first processing line LTR1 of a processing unit UT, said first processing line LTR1 providing at the output zero-centered velocity oscillations AW of the electric machine, C2) provide the angular velocity W of the electric machine as input to a second processing line LTR2 of the processing unit UT, said second processing line LTR2 providing as output two threshold values ​​WSmin, WSmax of the electric machine's velocity oscillations, a first threshold WSmin being defined for a negative torque value and a second threshold WSmax being defined for a positive torque value; and C3) compare, for example in a COMP comparator, over the threshold duration D s predetermined, the velocity oscillations AW obtained in substep Ci) at one of the thresholds WSmin, WSmax defined in substep C2) chosen according to the sign of torque Sc.

[0031] In step Ci), the angular velocity information W is processed to extract and isolate the wave component, i.e., the angular velocity oscillations AW, from the continuous component, which is the angular velocity W without the velocity oscillations. Refer to Figure 3a, described in more detail later, to better understand the processing performed by steps Ci), C2), and C3).

[0032] Furthermore, step Ci) may include the following sub-steps: - filter, using an FLT low-pass filter PB , the angular velocity W of the electric machine; - filter, with a high-pass filter FLT P the angular velocity filtered with the low-pass filter These filtering substeps allow the isolation of oscillations from the velocity AW; and possibly: - take the absolute value of the velocity oscillations |AW| previously obtained.

[0033] It is worth noting that the order of the filtering operations is not important. Therefore, one can perform low-pass filtering followed by high-pass filtering, or conversely, high-pass filtering followed by low-pass filtering.

[0034] Reference can be made to Figure 3b, described in more detail later in the description, to better identify the processing that may be carried out during step Ci).

[0035] Furthermore, step C2) may include the following sub-steps: - to process, with a first processing module PM1, the angular velocity W of the electric machine, to define two threshold torques CSmin, CSmax, a first threshold torque CSmin being defined for a negative torque value and a second threshold torque CSmax being defined for a positive torque value; - optionally, take the absolute value of the two threshold pairs CSmin, CSmax to define two threshold pairs CS*m in, CS* ma x corresponding; and - translate said threshold pairs CSmin, CSmax 5 (|CSmin|, |CSmax| where applicable) into threshold values ​​WSmin, WS ma x velocity oscillations.

[0036] It should be noted, for the purpose of making a viable comparison in step C3), that either both steps Ci) and C2) implement a substep of switching to an absolute value, or neither step Ci) and C2) implements such a substep.

[0037] The threshold duration D s The predetermined value implemented in step c) preferably depends on the period of the torsion mode. A threshold value between 2ms and 10ms can typically be chosen.

[0038] An example of the implementation of a DCEHP, DCEBP control device that can be implemented within the framework of the invention is illustrated in Figure 3a.

[0039] The DCEHP, DCEBP control device is configured to determine the currents flowing in the stator of the electric machine so that the electric machine rotor provides an electric machine torque TRQ conforming to a setpoint torque CEEC*. The control device includes a setting unit 31 for determining a setpoint current Iq* from the setpoint torque CEEC*. The control device also includes a setting unit 32 for determining a setpoint forward current Id*. The setpoint currents Iq*, Id* are converted into setpoint voltage Vq*, Vd* by a conversion unit 33 after correction of the setpoint currents lq*, Id* by PI (Proportional-Integral) operators from current measurements of the currents lq, Id flowing in the stator of the electric machine ME (which can refer to either the High Pressure electric machine MEHP or the Low Pressure electric machine MEBP).In this example, currents labc are measured at the stator of the electric machine ME and are represented vectorially by a forward current Id and a quadrature current lq, given an angular position 0 of the rotor relative to the stator. The electric machine ME is controlled via a vector control dq. The conversion unit 33 determines the setpoint voltages Vq*, Vd* based on the rotor speed W relative to the stator in order to perform flux defluxing. According to one aspect, the angular position 0 of the rotor 12 relative to the stator is obtained by a monitoring unit 36, which can be connected to an angular sensor 37 (or, alternatively, instead of the angular sensor 37, an observation unit not shown) allowing the angular position 0 to be determined from the measurement of the control currents labc.The monitoring unit 36 ​​also allows the determination of the angular velocity W of the electric machine, which is therefore either measured (via the use of the angular sensor 37) or estimated (via the use of the observation unit not shown in Figure 3a). The setpoint voltages Vq*, Vd* from the conversion unit 33 are transformed into a control voltage Vabc* by a dq / abc converter and then processed by a control unit 34 in order to provide a control parameter (PWM signal for example) to an inverter 35 supplying the electric machine ME, in particular, its stator.

[0040] The general structure and components of the DCE, DCEHP, DCEBP control device described above are known to those skilled in the art and are not presented in more detail.

[0041] Within the framework of the invention, the angular velocity W of the electric machine is used to limit or prevent any overtorque on the radial transmission shaft 22, particularly due to the torsional resonance mode of this shaft. As can be seen in Figure 3a, the angular velocity W of the electric machine serves as input data to a processing unit UT, which determines at output whether or not to maintain torque control CEEC.

[0042] This processing unit is now described in support of figures 3a, 3b and 3c.

[0043] The UT processing unit comprises two separate processing lines LTR1, LTR2 whose respective outputs are compared in a COMP comparator to determine whether or not to maintain torque control.

[0044] The first processing line LTR1 is designed to process the angular velocity W of the electric machine in order to isolate the oscillations related to the torsional resonance mode of the radial transmission shaft 22. To this end, the first processing line LTR1 includes, in the particular design illustrated, a low-pass filter FLT. PB followed by an FLT high-pass filter P and advantageously from an MFA1 module applying an "absolute value" function to its input data. The FLT low-pass filter PB Its purpose is to filter high frequencies on the angular velocity W of the electrical machine and thus eliminate measurement noise. The FLT high-pass filter P Its purpose is to isolate the wave component from the DC component of the velocity. Indeed, the velocity oscillations are proportional to the torque oscillations linked to the excitation of the torsional mode.

[0045] In an unillustrated variant, we could have first a high-pass filter and then a low-pass filter, each filter retaining its function as described previously.

[0046] Furthermore, combining a low-pass filter with a high-pass filter creates a band-pass filter. Alternatively, in another possible but unillustrated approach, a band-pass filter can be used directly. The cutoff frequencies of the band-pass filter are determined by the value of the torsion mode and the measurement noise frequency.

[0047] The velocity oscillations AW are centered around zero and can therefore be positive or negative. The MFA1 module, when present, makes all values ​​of these oscillations positive: this is advantageous for processing speed. However, the MFA1 module could be omitted, and the processing would work just as well, but would simply be more complex.

[0048] The second processing line, LTR2, comprises a PM1 module that defines a first threshold torque, CSmin (which must not be exceeded and is defined for a negative torque), and a second threshold torque, CSmax (also not to be exceeded and is defined for a positive torque). The first threshold torque, CSmin, can be user-defined; it can be constant, piecewise constant, or more generally defined by any function dependent on the angular velocity W of the electric machine. Similarly, the second threshold torque, CSmax, can be user-defined; it can be constant, piecewise constant, or more generally defined by any function dependent on the angular velocity W of the electric machine.It should be noted that the torque thresholds CSmin, CSmax (beyond which there is over-torque) are chosen so as to be greater than the level of electromagnetic torque applicable by the electric machine and less than the level of torque exceeding the infinite life threshold of the kinematic chain.

[0049] Advantageously, and necessarily when an MFA1 module is included in the first processing line LTR1, the second processing line LTR2 then includes an MFA2 module also applying an "absolute value" function. The CS max St CSmin thresholds are then redefined as |CS m in| and |CS ma x| respectively at the output of the MFA2 module.

[0050] Next, these threshold pairs |CS need to be translated m in| and |CS max| into data that will allow comparison. This is done in the MCV conversion module. The link is made via the fundamental relation of dynamics, the speed being obtained by dividing the torque by the quantity 2iT*f0*JM where f0 is the frequency of the torsional resonance mode of the radial transmission shaft 22 (Hz) and JM is the moment of inertia of the electrical machine (kg / m 2 ). It is indeed the additional contribution related to shaft 22 on the electric machine that is taken into account, which is consistent with considering only speed oscillations relative to a base value. When working in "absolute value," the thresholds must also be divided by two (we are no longer dealing with peak-to-peak), therefore dividing the torque by the quantity 2*2TT*fo*JM. At the output of the MCV conversion module, we thus obtain two speed thresholds and a maximum speed threshold WS. max (associated with a positive torque) and a minimum speed threshold WSmin (associated with a negative torque), strictly positive because they are expressed as absolute values ​​based on the threshold torques |CS m in| and |CS ma x| . We also understand that if the threshold pairs are constant, then the velocity thresholds WSmin, WS max are also constant. If the threshold pairs are piecewise constant, then the speed thresholds WSmin, WS max are also piecewise constant. Finally, if the threshold pairs depend on the speed W, then the speed thresholds WSmin, WS max also dependent on the speed W.

[0051] It should be noted that the frequency of the torsional resonance mode of the radial transmission shaft 22 depends on the torque level applied by the electric machine. Indeed, the greater the torque, the greater the torsional stiffness k0 of the shaft 22. Consequently, the frequency of the torsional resonance mode increases slightly with the torque, in accordance with the relationship derived from the fundamental equation of dynamics: 2iT*f0 = (k0 / Jw) 0 ' 5 . Thus, if we wish to be more precise, it is possible to create a map that takes into account the effect of the torque level on the stiffness ko of the torsion shaft.

[0052] For simplicity, we advantageously define a higher frequency for the torsional resonance mode, which we apply regardless of the torque level. In this case, the velocity oscillations at low torque levels are slightly amplified but do not trigger the mechanical over-torque protection.

[0053] The outputs of each of the LTR1 and LTR2 processing lines are then integrated into the COMP comparison module. The objective is to determine whether the velocity oscillations from the first LTR1 processing line are below the WSmin and WSmax threshold values ​​from the second LTR2 processing line.

[0054] The COMP comparison module includes two additional inputs, named Sc and D. s .

[0055] One of these inputs, Sc, aims to determine which threshold, WSmin and WSmax, should be used depending on whether the torque is negative or positive, respectively. This additional input therefore provides the sign of the torque. Indeed, the protection threshold can differ between motor mode and generator mode for the same rotational speed. To determine the sign of the torque, one can rely on the value of the electromagnetic torque (obtained by measuring the currents in the electrical machine). Alternatively, it is also possible to deduce it from the CEEC setpoint torque.

[0056] The other D s The aim of these entries is to determine the threshold duration D s beyond which the velocity from the first line of treatment LTR1 is above a threshold WSmin, WSmax from the second line of treatment LTR2. This duration D sA predetermined threshold (or confirmation time) can be set by the user. This prevents the system from taking into account a sudden and brief, or at least unrepresentative, exceedance of the speed W of one of the threshold values ​​WSmin, WSmax. In other words, and as mentioned in step d) of the method according to the invention, if the amplitude of the speed oscillations is strictly greater than one of the thresholds during the predefined confirmation time, then a mechanical overtorque is detected and the device will switch to protection mode by stopping the transmission of the torque command to the control device of the electrical machine.

[0057] In general, the invention thus proposes a hybrid turbomachine comprising: - an AHP, ABP propulsion shaft - an electrical machine MEHP, MEBP, - a mechanical transmission line LTMHP, LTMBP connecting the shaft to the electrical machine, said mechanical transmission line comprising a radial transmission shaft 22 capable of undergoing a torsional resonance mode, and - a control device DCEHP, DCEBP of the electrical machine comprising a means 36, 37 for determining the angular velocity W of the electrical machine and a processing unit UT for determining whether oscillations of the angular velocity W* of the electrical machine around a base value are strictly greater than a threshold value WSmin, WSmax over a threshold time D s predetermined, said control device being configured to receive a torque command CEEC.HP, CEEC.BP for the electrical machine and to stop this torque command when the speed oscillations W* are strictly greater than the threshold value WSmin, WSmax over the threshold duration D s predetermined.

[0058] Figures 4 to 7 present different results showing the benefit of the proposed regulation within the framework of the invention.

[0059] Figure 4 shows the mechanical torque (top, ordinate) as a function of time (x-axis), in this case measured with a CM torque meter, and correspondingly, the absolute value of the angular velocity oscillations of the electric machine (bottom, ordinate). Figure 4 illustrates what happens when the torsion mode is excited. Its purpose is simply to clearly identify the correlation between the two phenomena (torque variation / angular velocity oscillations).

[0060] Figure 5 shows the evolution of the mechanical torque (top), always measured by a CM torque meter, and the velocity oscillations (bottom) of the electric machine for a negative torque setpoint, as a function of time (abscissa).

[0061] Figure 5 (top) shows the height of the mechanical torque oscillations, in this case 45 Nm. Thus, if we imagine that the threshold torque is also 45 Nm, then by dividing by 2*2*TT*f0*JM we obtain a speed threshold WSmin of 7.2 rad / s.

[0062] Furthermore, Figure 5 (bottom) shows that the absolute velocity oscillations are on the order of 69 rpm, which corresponds to 7.2 rad / s. This value matches that calculated from the torque oscillations.

[0063] It is therefore clear here that protection against over-torque with the method according to the invention is feasible.

[0064] As previously stated, such protection is not feasible using electromagnetic torque.

[0065] Figures 6 and 7 confirm this.

[0066] Thus, in Figure 6, various torques (top, ordinates) and the angular velocity W (bottom, ordinates) of the electrical machine are plotted as a function of time (abscissa). At the top, the evolution of the setpoint torque CEEC (normalized constant part at 100%), the electromagnetic torque Cem, and the mechanical torque C can be followed. m .

[0067] These figures show that the electromagnetic torque Cem follows the setpoint torque CEEC, with a steady-state error of around 10% when the setpoint torque is constant. The torque C em also follows the form of the instruction during a couple step.

[0068] On the contrary, we can see in Figure 6 that the mechanical couple C mThe oscillations are clearly noticeable, with the height of the oscillations during the test being 2.2 times greater than the setpoint (measured by the torque meter) for a constant setpoint. The effect of the torsion mode of the radial transmission shaft 22 is clearly visible here. These torque oscillations result in speed oscillations of the electric machine, which can be visualized in the lower figure.

[0069] Figure 7 is an enlarged view of Figure 6 to better identify the details of the electromagnetic couple C em We can see that the oscillations of the electromagnetic couple C em are on the order of 1 / 300 of the setpoint. Protection based on electromagnetic torque is therefore not feasible. In Figure 7, we also see the setpoint electromagnetic torque Cem, setpoint (present in Figure 6, but difficult to identify in relation to C). em ).

[0070] Another example of an implementation of a DCE control device that can be used within the scope of the invention is illustrated in Figure 8. Here, a power command P*EEC is obtained and divided, in the DIV module, by the angular velocity W of the electric machine. This allows, at the output of the DIV module, a setpoint torque C*EEC (command) to be obtained, which can be associated with the setpoint torque shown in Figure 3a. The rest is identical to what occurs in the control device described previously in support of Figure 3a.

[0071] Additional voltage regulation can also be added at a higher level, whether in the diagrams of figures 3a, 3b or 3c or in the diagram of figure 8.

[0072] The invention offers several advantages.

[0073] Besides preventing any mechanical over-torque on the drivetrain, this software-based control relies on data already provided by conventional control systems (vector control, with or without a position sensor, see 37) without adding any components such as a torque meter, which is difficult to integrate into turbomachinery and can fail, forcing the electrical system responsible for the hybridization into protection mode. Consequently, it has no additional mass and does not alter the overall dynamics of the drivetrain, which can change if an additional sensor is added.

Claims

Demands [1] Method for controlling a hybrid turbomachine, said turbomachine comprising a propulsion shaft (AHP, ABP), at least one electric machine (MEHP, MEBP), a mechanical transmission line (LTMHP) between the shaft (AHP, ABP) and the electric machine (MEHP, MEBP), said mechanical transmission line (LTMHP) comprising a radial transmission shaft (22) capable of undergoing a torsional resonance mode and a control device (DCE, DCEHP, DCEBP) for the electric machine, the method comprising the following steps: a) apply a torque control (CEEC.HP, CEEC.BP) at the level of the electrical machine via the electrical machine control device; b) determine the angular velocity (W) of the electric machine; c) determine, using computer implementation, whether zero-centered angular velocity (AW) oscillations of the electric machine are strictly greater than a threshold value (WSmin, WSmax) over a threshold time (D s ) predetermined and if so: d) stop applying the torque control for the electric machine. [2] Method according to claim 1, wherein, in step b), the angular velocity (W) of the electric machine is measured. [3] Method according to claim 1, wherein, in step b), the angular velocity (W) of the electric machine is estimated. [4] A method according to any one of the preceding claims, wherein the threshold value (WSmin, WSmax) defined in step c) depends on the speed (W) of the electric machine. [5] A method according to any one of the preceding claims, wherein, in order to determine, during step c), whether the zero-centered angular velocity (AW) oscillations of the electric machine are strictly greater than the threshold value (WSmin, WSmax) over the threshold time (D s ) predetermined, step c) of the process includes the following steps: C1) provide the angular velocity (W) of the electric machine as input to a first processing line (LTR1) of a processing unit (UT), said first processing line (LTR1) providing as output zero-centered velocity oscillations (AW) of the electric machine; C2) provide the angular velocity (W) of the electric machine as input to a second processing line (LTR2) of the processing unit (UT), said second processing line (LTR2) providing as output two threshold values ​​(WSmin, WSmax) of the electric machine's velocity oscillations, a first threshold (WSmin) being defined for a negative torque value and a second threshold (WSmax) being defined for a positive torque value; and C3) compare, over the threshold duration (D s ) predetermined, the velocity oscillations (AW) obtained in substep Ci) at one of the thresholds (WSmin, WSmax) defined in substep C2) chosen according to the sign of torque (Sc). [6] A method according to the preceding claim, wherein step Ci) comprises the following substeps: - filter, using a low-pass filter (LPF) PB ), the angular velocity (W) of the electric machine; - filter, using a high-pass filter (FLT) P ), the angular velocity filtered with the low-pass filter; these substeps allow us to obtain the oscillations of the velocity AW centered at zero; and possibly: - take the absolute value of the previously obtained velocity oscillations. [7] A method according to claim 5, wherein step Ci) comprises the following substeps: - filter, using a high-pass filter (FLT) P ), the angular velocity (W) of the electric machine; - filter, using a low-pass filter (LPF) PB ), the angular velocity filtered with the high-pass filter; these substeps allow us to obtain the oscillations of the velocity AW centered at zero; and possibly: - take the absolute value of the previously obtained velocity oscillations.[8] Method according to claim 5, wherein step Ci) comprises the following substeps: - filter, with a bandpass filter (FLTPH), the angular velocity (W) of the electric machine, this sub-step allowing the oscillations of the velocity AW to be obtained centered at zero; and possibly: - take the absolute value of the previously obtained velocity oscillations. [9] A method according to any one of claims 4 to 8, wherein step C2) comprises the following substeps: - process, in a first processing module (PM1), the angular speed (W) of the electric machine to obtain two threshold torques (CSmin, CSmax), a first threshold torque (CSmin) being defined for a negative torque value and a second threshold torque (CSmax) being defined for a positive torque value; - optionally, take the absolute value of the two threshold pairs (CSmin, CSmax) to define two threshold pairs (|CS m in| , |CS ma x|) corresponding; and - translate the said threshold pairs (CSmin, CSmax 5 |C min|j |CSmax|) SH VHIGUTS S6UÜS (WSmin ws max ) of the velocity oscillations. [10] A method according to any one of the preceding claims, wherein the threshold duration (D s ) predetermined implementation in step c) is at least 2ms, for example between 2ms and 10ms. [11] A method according to any one of the preceding claims, wherein the torque control supplied in step a) is derived from a power control divided by the angular velocity (W) of the electric machine. [12] Hybrid turbomachine comprising: - a propulsion shaft (AHP, ABP), - an electrical machine (MEHP, MEBP), - a mechanical transmission line (LTMHP, LTMBP) connecting the shaft to the electric machine, said mechanical transmission line comprising a radial transmission shaft (22) capable of undergoing torsional resonance, - a control device (DCEHP, DCEBP) for the electric machine comprising a means (36, 37) for determining the angular velocity (W) of the electric machine and a processing unit (UT) for determining whether zero-centered angular velocity (AW) oscillations of the electric machine are strictly greater than a threshold value (WSmin, WSmax) over a threshold time (Ds ) predetermined, said control device being configured to receive a torque command (CEEC.HP, CEEC.BP) at the level of the electrical machine and to stop this torque command when the speed oscillations (AW) are strictly greater than the threshold value (WSmin, WSmax) over the threshold time (D s ) predetermined. [13] Aircraft comprising at least one hybrid turbomachine according to claim 12.

Images