Power transition management method between power generation modes

Abstract

A method for managing a power transition between a first power generation mode and a second power generation mode in a turbine engine, the turbine engine having a high-pressure shaft from which high-pressure power is extracted and a low-pressure shaft from which low-pressure power is extracted, the first power generation mode corresponding to a first power distribution between the high-pressure power and the low-pressure power, the second power generation mode corresponds to a second power distribution between the high-voltage power and the low-voltage power, the sum of the high-voltage power and the low-voltage power extracted in each power generation mode defines the same total power, and a transition between the first power generation mode and the second power generation mode occurs within a predetermined time period (t2-t1), meanwhile, the same smoothing function f (t) is applied to the high-voltage power and the low-voltage power, and the total power is not changed.

Description

Technical Field

[0001] The present invention relates to the field of internal hybridization of turbomachines for multi-electric or highly electrified aircraft. Background Art

[0002] Climate change is a major concern for many legislative and regulatory bodies around the world. In fact, various carbon emission restriction measures have been adopted or are about to be adopted by countries. In particular, an ambitious standard applies not only to new aircraft but also to those currently in circulation, requiring the implementation of technical solutions to bring them into compliance with current regulations. Civil aviation has been mobilized for many years to contribute to the fight against climate change.

[0003] Technical research work has led to a significant improvement in the environmental performance of aircraft. The applicant has taken into account the influencing factors at all stages of design and development to obtain aviation components and products with lower energy consumption and more environmentally friendly, and their integration and use in civil aviation have less impact on the environment, aiming to improve the energy efficiency of these aircraft.

[0004] Therefore, the applicant is continuously committed to reducing its climate impact by using various methods, developing virtual research, development and manufacturing methods, and minimizing greenhouse gas emissions as much as possible, in order to reduce the environmental footprint of its activities.

[0005] This continuous research and development work applies to new generation aircraft turbomachines, lightweight machinery (especially through the use of materials and lightweight airborne equipment), the development of electric power technologies for providing propulsion, and aviation biofuels, which are an essential complement to technological progress.

[0006] The hybridization of the turbomachine is achieved through an electrical system that forms an interface between the mechanical shaft of the turbomachine and the aircraft electrical network.

[0007] This system must be able to ensure the function of starting the turbomachine (high pressure and / or low pressure), generating controlled electric power to supply propulsion and non-propulsion loads, and injecting or extracting power from the turbomachine shaft in a controlled manner to assist the turbomachine if necessary. The balance between the power consumed by the loads and the power generated by the available power sources is achieved by controlling the bus voltage (for alternating voltage, controlling the frequency and maximum amplitude; for direct voltage, controlling the amplitude), while complying with the constraints of the system.

[0008] Traditionally, as Figure 9As shown, the internal hybrid system architecture of the turbomotor 100 is based on a parallel-connected DC channel, typically a high-voltage channel (corresponding to the high-pressure shaft 102 of the turbomotor) and a low-voltage channel (corresponding to its low-pressure shaft 104). Each of these two DC channels is implemented by an electric machine 106, 108 (typically a synchronous permanent magnet machine) and is associated with a controlled reversible AC / DC power converter 110, 112, which supplies a DC voltage to a DC bus 114 connected to the load to be powered (propulsion and / or non-propulsion load) 116. The control of the reversible power converter is typically provided by a control module 118, which receives instructions from the electronic control unit ECU 120 of the turbomotor.

[0009] An external power source (typically a set of batteries or supercapacitors) is associated with a reversible DC / DC converter (this combination is not shown) and can also be connected in parallel with these high-voltage and low-voltage channels to supply power to the high-voltage and / or low-voltage shaft, for example during the start-up of the turbomotor.

[0010] Generating electricity from the high-voltage and low-voltage shafts of the turbomotor has different effects on its performance (operability) or the thrust generated depending on the shaft from which the power is extracted. Therefore, the controller of the turbomotor especially has the function of adjusting the participation percentage of the electric machine in this power generation during the flight mission to optimize its operating point. For this purpose, the ECU 120 will request the control module 118 to distribute the extracted power between the high-voltage and low-voltage shafts to supply the grid load 116, which typically has a dynamically varying behavior (especially so-called active loads).

[0011] As Figure 10 shown, the ECU requests the distribution of the extracted power between the high-voltage and low-voltage shafts, which may vary according to several consecutive modes during the flight mission, such as a first power generation mode (extracting 60% of the power from the high-voltage shaft and 40% of the power from the low-voltage shaft) and a second power generation mode (as shown, extracting 100% of the power from the low-voltage shaft). However, when changing the power generation mode (at time t0), due to the instantaneous change in the power distribution ratio, an extraction impact will be generated on each shaft of the turbomotor, and its transient will cause a disturbance in the turbomotor regulation, thereby causing the suppression of low-frequency disturbances (typically <1 Hz). The impact on the mechanical shaft may also excite undesired mechanical modes.

[0012] Document US20220371532 proposes an electrical system that includes a first electric machine connected to a first gas turbine and a second electric machine connected to a second gas turbine. Summary of the Invention

[0013] To this end, the present invention is a technical research result aimed at significantly improving the performance of aircraft, and in this sense, it helps to reduce the environmental impact of these aircraft. Therefore, the main object of the present invention is to limit the impact of power extraction when changing the power generation mode while complying with the quality constraints of the power grid. Another objective is to allow the management of possible load impacts during such a change in the power generation mode.

[0014] These objectives are achieved by a method for managing the power transition between a first power generation mode and a second power generation mode in a turbomachine, the turbomachine having a high-pressure shaft from which high-pressure power is extracted and a low-pressure shaft from which low-pressure power is extracted, the first power generation mode corresponding to a first power distribution between the high-pressure power and the low-pressure power, the second power generation mode corresponding to a second power distribution different from the first distribution between the high-pressure power and the low-pressure power, the sum of the high-pressure and low-pressure powers extracted in each power generation mode defining the same total power, characterized in that the transition between the first power generation mode and the second power generation mode occurs within a predetermined time period (t2 - t1) without changing the total power, and the same smoothing function f(t) is applied to the extraction of the high-pressure power and the low-pressure power.

[0015] Thus, by ensuring the smooth processing of the power extraction setpoint during power generation, the regulation of the turbomachine is not disturbed, and there is no need to worry about the excitation of undesirable mechanical modes. Since the total power remains unchanged, the quality of the power grid is ensured.

[0016] Preferably, the smoothing function f(t) is a continuous or discrete bounded [0; 1] monotonic function, and f(t1) = 0 and f(t2) = 1, typically a linear function f(t) = Kt, (K being a scaling factor) or a first-order function of the type f(t) = 1 - exp(-t / τ) (τ being a time constant).

[0017] Advantageously, the predetermined duration includes 1 to 10 seconds.

[0018] Preferably, when a load impact corresponding to an additional power extraction occurs during the transition, this additional extraction is carried out according to the first power distribution or the second power distribution at the moment of the impact, and the smoothing function f(t) is applied from the start of the transition until the end of the transition after this moment.

[0019] According to the embodiment considered, the additional power extraction is carried out from each high-pressure or low-pressure shaft according to a first power distribution and satisfies the following equation: P = (1 - f(t)) * P0(t) + f(t) * P1(t), or even according to a second power distribution from each high-pressure or low-pressure shaft and satisfies the following equation: P = (1 - f(t)) * P0(t1) + f(t) * P1(t1) + P1(t) - P1(t1), where P0 is the power required for the first power generation mode, P1 is the power required for the second power generation mode, and t1 is the time of mode change.

[0020] The invention also relates to a turbomachine (typically an aircraft turbomachine such as a hybrid turbofan, a hybrid turboprop or a hybrid helicopter turbomachine) implementing the above method.

[0021] More specifically, the turbomachine may further include an adapter module configured to generate a smoothing function and arranged between a control module receiving a power setpoint from an ECU and a power converter associated with an electric machine mounted on the high-pressure and low-pressure shafts.

[0022] Brief description of the drawings

[0023] Other features and advantages of the invention will be revealed by the following description in conjunction with the drawings, which show one of its embodiments without any limitation, wherein:

[0024] Figure 1 Shows the architecture of an internal hybrid system of a turbomachine according to the invention;

[0025] Figure 2 Shows the influence of the invention on the extraction power setpoint;

[0026] Figure 3 Shows a first example of the shape of the extraction power setpoint after additional extraction in the transition phase;

[0027] Figure 4 Shows allowing to obtain Figure 3 A first example of the establishment of the control logic for the setpoint shape;

[0028] Figure 5 Shows allowing to obtain Figure 3 A first example of the different steps of the method for the setpoint shape;

[0029] Figure 6 Shows a second example of the shape of the power extraction setpoint after additional extraction in the transition phase;

[0030] Figure 7 Shows allowing to obtain Figure 6 A second example of the establishment of the control logic for the setpoint shape;

[0031] Figure 8 shows different steps of a second example of a method for obtaining Figure 6 a setpoint shape;

[0032] Figure 9 shows the architecture of an in - line hybrid system of a prior - art turbomachine;

[0033] Figure 10 shows the power extraction setpoints associated with the prior - art architecture.

[0034] Embodiment description

[0035] The principle of the present invention relies on, when changing the power generation mode, by introducing a smoothing function of the power extraction setpoint while ensuring that the total extracted power can supply the turbomachine and the electrical network of the aircraft, thereby limiting the impact of power extraction on the high - pressure (HP) and / or low - pressure (LP) shafts.

[0036] As Figure 1 shown (the same modules as in the prior art are given the same reference signs and are not described again), a smoothing function f(t) allowing a smooth transition between two power generation modes is obtained by adding an adapter module 200, which is used to process the setpoints obtained from the ECU and sent to the electric motors. This module is arranged between the control module 118 and the power converters 110, 112 associated with the electric motors 106, 108 mounted on the high - pressure and low - pressure shafts 102, 104.

[0037] Figure 2 shows the power extraction setpoints during the transition phase (smoothing process), which reflects the change in the power generation mode, after integrating the smoothing function performed by the adapter module 200. It can be noted that the transition from the first power generation mode (extracting 60% of the power from the high - pressure shaft and 40% of the power from the low - pressure shaft) to the second power generation mode (extracting 100% of the power from the low - pressure shaft) no longer occurs instantaneously at a given time t0 as in the prior art, but is distributed over a longer time period (typically including 1 to 10 seconds), between time t1 and time t2, during which the power extracted from each shaft gradually (instead of suddenly) transitions from its current level in the first power generation mode to its future level in the second power generation mode without changing the total power consumed by the electrical network.

[0038] Providing such a smoothing function f(t) with a progressive increase is typically a linear function f(t)=Kt (K is a scaling factor) or a first - order function of the type f(t)=1 - exp( - t / τ) (τ is the time constant). However, these two preferred function types should not be considered restrictive; functions in the Laplace domain satisfying the transfer function f(p)=1 / (p 2 / ω 2A second-order function of (+2mp / ω + 1) (where m is the damping coefficient ≥ 1), and these first-order and second-order functions can also be considered for application to the above linear function. More generally, any continuous or discrete bounded [0; 1] monotonic function with f(t1) = 0 and f(t2) = 1 may be applicable.

[0039] As previously mentioned, since the transition stage is not instantaneous, it is necessary to consider the situation where power extraction requirements occur during this transition stage (before reaching the steady state).

[0040] According to the present invention, two allocation solutions are considered. The first is as Figures 3 to 5 shown, where the difference in power demand is handled in the same way as the initial power demand, that is, the two modes are proportionally allocated depending on the allocation function; while the second is as Figures 6 to 8 shown, and the difference in power demand adopts the second power generation mode. It should be noted that if the demand does not change during the transition, these two solutions are equivalent.

[0041] In the first solution, therefore, when a load impact occurs during the transition, the defined extraction power allocation continues to be applied.

[0042] Figure 3 shows the shape of the power setpoint obtained using this initial allocation. For example, if the total power P0 is to be delivered, the initial power allocation is 60% from the high-pressure shaft and 40% from the low-pressure shaft, and it is desired to transition to 0% from the high-pressure shaft and 100% from the low-pressure shaft, and if during the transition stage between time t1 and time t2, at time t i there is a change in the consumer power demand (such as an additional demand of 50% as shown in the figure to reach the total power P1), then in this case, the new power demand of the consumer will be extracted at the level of 60% from the high-pressure shaft and 40% from the low-pressure shaft at the application point of the extraction change.

[0043] This solution is represented by the following equation in mathematical terms:

[0044] P HP = (1 - f(t)) * P 0HP (t) + f(t) * P 1HP (t)

[0045] P LP = (1 - f(t)) * P 0LP (t) + f(t) * P 1LP (t)

[0046] where P0 is the power demand in the first power generation mode (from the high-pressure shaft or the low-pressure shaft respectively), and P1 is the power demand in the second power generation mode (from the high-pressure shaft or the low-pressure shaft respectively).

[0047] Figure 4Shows the control logic implemented in the adapter module to satisfy the equation. It is typically organized around different functional blocks that will formulate the current setpoint (setpoint) based on the selected power generation mode (Mode) and the evolution of the setpoint (setpoint vector): mode change detection block 300, transition prohibition block 302, previous mode and new mode storage block 304, previous power setpoint generation block 306, new power setpoint generation block 308, transition generation block 310, and previous power setpoint and new power setpoint combination block 312.

[0048] Now Figure 5 Shows the different steps for transitioning from a first power generation mode to a second power generation mode. In the first step 400, the power setpoint of the high-pressure shaft is x1% (e.g., 60%) of the consumed power, and the power setpoint of the low-pressure shaft is y1% (e.g., 40%) of the consumed power, defining the power demand P0 in the first power generation mode. In the next step 402, at time t1, a power ratio power generation mode change request is detected, and then in the new step 404, the transition is initiated by applying a smoothing function f(t). In the next step 406, at time t i , due to the additional demand that brings the power to the power demand P1 in the second power generation mode, the load impact ΔP (P1 - P0) is observed, and this load impact is immediately fed back to the high-pressure and low-pressure powers according to the initial power distribution. In the next step 408, the dynamics of the transition are restored based on the smoothing function until the transition ends at time t2, and in the last step 410, a steady state of power P1 is obtained at a power ratio of x2% for the high-pressure and y2% for the low-pressure.

[0049] In the second scenario, when a load impact occurs during the transition (i.e., the power setpoint changes are extracted), the power distribution expected to be achieved after the desired power generation mode change is applied.

[0050] Figure 6 Shows the shape of the power setpoint obtained using this final distribution. For example, if the total power P0 is to be delivered, the initial power distribution is 60% from the high-pressure shaft and 40% from the low-pressure shaft, and it is desired to transition to 0% from the high-pressure shaft and 100% from the low-pressure shaft, and if during the transition phase between time t1 and time t2, at time t i a change in the consumer power demand occurs (e.g., an additional demand of 50% as shown in the figure to reach the total power P1), then in this case, the new power demand of the consumer will be extracted at the level of 0% from the high-pressure shaft and 100% from the low-pressure shaft until the steady state is reached.

[0051] This scenario is represented by the following equation in mathematical terms:

[0052] P HP =(1 - f(t))*P 0HP (t1)+f(t)*P1HP (t1) + P 1HP (t) - P 1HP (t1)

[0053] P lP = (1 - f(t)) * P 0LP (t1) + f(t) * P 1LP (t1) + P 1LP (t) - P 1LP (t1)

[0054] where P0 is the power demand in the first power generation mode (from the high-pressure shaft or the low-pressure shaft respectively), P1 is the power demand in the second power generation mode (from the high-pressure shaft or the low-pressure shaft respectively), and t1 is the time of mode change.

[0055] Figure 7 Shows the control logic implemented in the adapter module to satisfy this equation. It is typically organized around different functional blocks that will formulate the current setpoint (setpoint) based on the evolution of the power generation mode (Mode) and the setpoint vector: mode change detection block 300, transition prohibition block 302, previous power setpoint generation block 306, new power setpoint generation block 308, transition generation block 310, and previous power setpoint and new power setpoint combination block 312.

[0056] Now Figure 8 Shows the different steps of transitioning from the first power generation mode to the second power generation mode. In the first step 400, the power setpoint from the high-pressure shaft is x1% of the power consumption (e.g., 60%), and the power setpoint from the low-pressure shaft is y1% of the power consumption (e.g., 40%), defining the power demand P0. In the next step 402, at time t1, a request for a change in the power generation mode of the power ratio is detected, and then in the next step 404, the transition phase is started by applying the smoothing function f(t). In step 406, at time t i , due to the additional demand, the total power reaches the power demand P1 in the second power generation mode, and the load impact ΔP (P1 - P0) is observed, and this load impact is immediately fed back to the high-pressure and low-pressure powers according to the final power distribution. In the next step 412, the dynamics of the transition are restored based on the smoothing function until the transition ends at time t2, and in the last step 410, a steady state of the power demand P1 is obtained at a power ratio of x2% for the high-pressure and y2% for the low-pressure.

[0057] It should be noted that the present invention is applicable to the internal hybridization of a turbine engine, regardless of the number of electric motors installed on the propulsion system and the type of turbine engine, such as a hybrid turbofan, a hybrid turboprop, or a hybrid helicopter turbine engine.

Claims

1. A method for managing a power transition between a first power generation mode and a second power generation mode in a turbomachine (100), the turbomachine having a high-pressure shaft (102) from which high-pressure (HP) power is extracted and a low-pressure shaft (104) from which low-pressure (LP) power is extracted, the first power generation mode corresponding to a first power distribution between the high-pressure power and the low-pressure power, the second power generation mode corresponding to a second power distribution between the high-pressure power and the low-pressure power that is different from the first power distribution, the sum of the high-pressure power and the low-pressure power extracted in each power generation mode defining the same total power, characterized in that, The transition between the first power generation mode and the second power generation mode occurs within a predetermined time period (t2 - t1) without changing the total power, while applying the same smoothing function f(t) to the extraction of high-pressure power and low-pressure power.

2. The power transition management method according to claim 1, wherein the smoothing function f(t) is a continuous or discrete bounded [0; 1] monotonic function, and f(t1) = 0 and f(t2) = 1.

3. The power transition management method according to claim 2, wherein the smoothing function f(t) is a linear function f(t) = Kt, where K is a scaling factor; or a first-order function of the type f(t) = 1 - exp(-t / τ), where τ is a time constant.

4. The power transition management method according to claim 1, wherein the predetermined time period (t2 - t1) comprises from 1 to 10 seconds.

5. The power transition management method according to any one of claims 1 to 4, wherein when a load impact corresponding to an additional power extraction (P) occurs during the transition, the additional extraction is performed at the impact moment (t i ) according to a first power distribution or a second power distribution, and the smoothing function f(t) is applied from the start of the transition (t1) until that moment and continues to be applied until the end of the transition (t2) after that moment.

6. The power transition management method according to claim 5, wherein the additional power extraction P from each high-pressure shaft or low-pressure shaft according to the first power distribution satisfies the following equation: P = (1 - f(t)) * P0(t) + f(t) * P1(t), where P0 is the power required for the first power generation mode and P1 is the power required for the second power generation mode.

7. The power transition management method according to claim 5, wherein the additional power extraction P from each high-pressure shaft and low-pressure shaft according to the second power distribution satisfies the following equation: P = (1 - f(t)) * P0(t1) + f(t) * P1(t1) + P1(t) - P1(t1), where P0 is the power required for the first power generation mode, P1 is the power required for the second power generation mode, and t1 is the time of mode change.

8. A turbomachine (100) having a high-pressure shaft (102) from which high-pressure (HP) power is extracted and a low-pressure shaft (104) from which low-pressure (LP) power is extracted, a first power generation mode corresponding to a first power distribution between the high-pressure power and the low-pressure power, a second power generation mode corresponding to a second power distribution different from the first power distribution between the high-pressure power and the low-pressure power, the sum of the high-pressure power and the low-pressure power extracted in each power generation mode defining the same total power, characterized in that, The transition between the first power generation mode and the second power generation mode occurs within a predetermined time period (t2 - t1) without changing the total power, while applying the same smoothing function f(t) to the extraction of high-pressure power and low-pressure power.

9. The turbomachine according to claim 8, further comprising an adapter module (200) configured to generate the smoothing function f(t) and arranged between a control module (118) receiving a power setpoint from an ECU (120) and power converters (110, 112) associated with electric machines (106, 108) mounted on a high-pressure shaft and a low-pressure shaft.

10. The turbomachine according to claim 9, constructed as an aero-turbomachine, such as a hybrid turbofan, a hybrid turboprop or a hybrid helicopter turbomachine.

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