Method for managing power transfer between power generation mode and auxiliary mode

Abstract

The invention relates to a method for managing power transfer of a turbine engine between a power generation mode and an assistance mode, the turbine engine having a high pressure shaft driving a high pressure electric machine and a low pressure shaft driving a low pressure electric machine, a high pressure power (PHP) being extracted from the high pressure shaft and a low pressure power (PBP) being extracted from the low pressure shaft, the power generation mode corresponding to a predetermined power sharing between the high pressure power and the low pressure power and the assistance mode corresponding to a request for injecting additional power onto the high pressure shaft or the low pressure shaft, in which method, to reach the requested additional power, when the extraction of the high pressure power or the low pressure power is interrupted and the high pressure electric machine or the low pressure electric machine driving the high pressure or the low pressure shaft whose extraction is interrupted enters a motor mode, the remaining power extracted from the high pressure shaft or the low pressure shaft in the generator mode is adjusted according to the high pressure or low pressure injection power output from the high pressure electric machine or the low pressure electric machine which has entered the motor mode.

Description

Technical Field

[0001] This invention relates to the field of internal hybrid power in turbine engines of more electrified or even highly electrified aircraft. Background Technology

[0002] Climate change is a focal point for numerous legislative and regulatory bodies worldwide. Specifically, countries have already implemented, are implementing, or are about to implement various carbon emission limits. Furthermore, an ambitious standard applies to both new and currently in-service aircraft, requiring the implementation of technological solutions to ensure compliance with existing regulations. For many years, the civil aviation industry has been committed to contributing to addressing climate change.

[0003] Technological research and development has made it possible to significantly improve the environmental performance of aircraft. The applicant has considered factors affecting all design and development phases to obtain aerospace components and materials that are more energy-efficient, more environmentally friendly, and have a moderate environmental impact when integrated and used in civil aviation, with the aim of improving the energy efficiency of these aircraft.

[0004] Therefore, the applicant is making continuous efforts to reduce its climate impact by using various methods and developing benign development and manufacturing processes that minimize greenhouse gas emissions, thereby reducing the environmental footprint of its activities.

[0005] This ongoing research and development effort involves next-generation aircraft turbine engines, lightweighting of aircraft (particularly through the materials used and lighter avionics), the development of propulsion using electric technologies, and aviation biofuels as an important complement to technological advancements.

[0006] The turbine-engine hybrid power system is achieved by an electrical system that forms the interface between the mechanical shaft of the turbine engine and the aircraft's electrical grid.

[0007] This system must enable the turbine engine (HP and / or LP) to start, generate controlled electrical power to supply propulsion and non-propulsion loads and injection, and output power from the turbine engine shaft in a controlled manner during turbine engine operation in auxiliary mode. By controlling the bus voltage (frequency and maximum amplitude for AC voltage, and amplitude for DC voltage), a balance must be ensured between the power consumed by the loads and the power generated by the available power source, while adhering to system constraints.

[0008] More precisely, when the turbine engine requires assistance, the power source involved in regulating the generator voltage will cease generating electricity and switch to electric motor mode. This switching of operating modes causes a sharp voltage fluctuation, which then shifts away from the predefined voltage envelope (…). Figure 5This envelope defines the limits that a turbine engine cannot exceed under normal 500 operation and abnormal operation (network problem, i.e., short circuit) 502 transient and steady-state conditions.

[0009] To control the voltage and keep it within these envelopes, known practices include temporarily reconfiguring the electrical system to reduce the load (e.g., non-priority loads), using an external power source with a dynamic range greater than that of the turbine engine power supply (whether or not associated with temporary load reduction) to supply the high-frequency (HF) portion of the power to be generated, or over-sizing certain passive components of the electrical system (such as capacitors for power electronics).

[0010] However, these solutions are not without drawbacks. Load reduction does not include any prediction of power consumption or grid behavior, and adding an external power source relies entirely on frequency sharing of the power generated between the turbine engine and that external power source, with the turbine engine supplying only average power. Finally, the excessive size of the system incurs a mass penalty and is therefore largely undesirable for aerospace applications. Summary of the Invention

[0011] To this end, based on the results of technological research, this invention aims to significantly improve aircraft performance and thereby help reduce the environmental impact of these aircraft. Therefore, the main objective of this invention is to limit sharp voltage fluctuations when a turbine engine enters auxiliary mode, predict sudden changes in available power, and without any onboard weight penalty, while meeting grid quality constraints.

[0012] These objectives are achieved by a method for managing power transfer between a turbine engine in generator mode and auxiliary mode, the turbine engine having a high-voltage shaft driving a high-voltage motor and a low-voltage shaft driving a low-voltage motor, outputting high-voltage power from the high-voltage shaft and low-voltage power from the low-voltage shaft, the generator mode corresponding to a predetermined power sharing between the high-voltage and low-voltage power, and the auxiliary mode corresponding to a request to inject additional power into the high-voltage or low-voltage shaft, characterized in that, in order to achieve the requested additional power, when the high-voltage or low-voltage power output is interrupted and the high-voltage or low-voltage motor driving the interrupted high-voltage or low-voltage shaft enters motor mode, the remaining output power of the high-voltage or low-voltage shaft in generator mode is adjusted based on the injected high-voltage or low-voltage power from the high-voltage or low-voltage motor already in motor mode.

[0013] Therefore, by sending the power requested by the power source entering auxiliary mode to the power source in generating mode, the request can be predicted, voltage variations can be limited, and transient response can be controlled, while keeping the voltage within a defined envelope.

[0014] Preferably, if the high-voltage motor or the low-voltage motor has different dynamic ranges, the injection of the requested additional power is accomplished by adjusting the dynamic range of the remaining output high-voltage power or low-voltage power.

[0015] The present invention also relates to a turbine engine having: a high-pressure shaft and a low-pressure shaft, the high-pressure shaft outputting high-pressure power and the low-pressure shaft outputting low-pressure power; a control module receiving a power setpoint from an ECU and a power converter associated with a high-pressure motor and a low-pressure motor respectively mounted on the high-pressure shaft and the low-pressure shaft; a generator mode corresponding to a predetermined power sharing between the high-pressure power and the low-pressure power; and an auxiliary mode corresponding to injecting additional power into the high-pressure shaft or the low-pressure shaft, characterized in that, in order to achieve the requested additional power, the control module is configured such that: when the output of the high-pressure power or the low-pressure power is interrupted and the high-pressure motor or the low-pressure motor of the interrupted high-pressure shaft or the low-pressure shaft respectively enters a motor mode, the remaining output power of the high-pressure shaft or the low-pressure shaft in the generator mode is adjusted based on the injected high-pressure or low-pressure power from the high-pressure motor or the low-pressure motor already in the motor mode.

[0016] Preferably, the control module further includes an auxiliary module and a selection module, wherein the auxiliary module is configured to add the injected high-voltage or low-voltage power to the remaining output high-voltage or low-voltage power, and the selection module is configured to select the output power from the auxiliary module.

[0017] Preferably, each auxiliary module includes an adder and an adaptive module, the adaptive module having transfer functions F1 and F2 for adjusting the dynamic range of the remaining output high-voltage power or low-voltage power according to the corresponding dynamic range of the high-voltage motor and the low-voltage motor.

[0018] Depending on the dynamic range of the motor, if the high-voltage and low-voltage motors have the same dynamic range, the transfer function is equal to 1; if the dynamic range of the motor entering motor mode is slower than the dynamic range of the motor remaining in generator mode, the transfer function is a phase delay; if the dynamic range of the motor entering motor mode is faster than the dynamic range of the motor remaining in generator mode, the transfer function is a phase advance function. Attached Figure Description

[0019] Other features and advantages of the invention will become apparent from the following description with reference to the accompanying drawings, which illustrate only exemplary embodiments of the invention but are not intended to limit it in any way, and in the drawings:

[0020] [ Figure 1 ] Figure 1 The diagram illustrates the architecture of the internal hybrid power system of the turbine engine according to the present invention.

[0021] [ Figure 2 ] Figure 2 Detailed Figure 1 The innovative control module for the internal hybrid power system,

[0022] [ Figure 3 ] Figure 3 The diagram illustrates the output setpoint of the power associated with the request for assistance.

[0023] [ Figure 4 ] Figure 4 It shows in Figure 1 The different steps of the method implemented in the internal hybrid power system, and

[0024] [ Figure 5 ] Figure 5 It shows the applicable Figure 1 An example of the voltage envelope of an internal hybrid power system. Detailed Implementation

[0025] When a request for auxiliary power is received, the turbine power supply involved in regulating the generator voltage will stop operating and switch to electric motor mode to inject the necessary power and provide auxiliary functions for the turbine. Because the remaining power sources have a certain response time—the time it takes for them to reconfigure to supply insufficient power—the generator voltage will drop significantly and exceed the set envelope limit, especially when the balance between generated and consumed power is no longer maintained.

[0026] To address this issue, the present invention proposes that, following a request for assistance to the turbine engine, the control module of the remaining power source be actuated to modify its behavior so that the transient response of the generated voltage remains contained within a predefined envelope.

[0027] Figure 1 The illustration shows an example of the architecture of an internal hybrid power system for a turbine engine 100, based on parallel-connected DC channels, typically an HP channel (corresponding to the high-pressure shaft 102 of the turbine engine) and an LP channel (corresponding to its low-pressure shaft 104). These two DC channels are each driven by motors 106 and 108, typically permanent magnet synchronous machines, and are associated with controlled AC-DC reversible power converters 110 and 112, which deliver DC voltage to a DC bus 114 connected to a load 116 (propulsion or non-propulsion) to be powered. Control of the reversible power converters is conventionally provided by a control module 118, which receives instructions from a controller in the turbine engine ECU (electronic control unit) 120 that controls the combustion engine and therefore has the particular function of allocating the percentage of the motor's contribution to power generation to optimize the turbine engine's operating point.

[0028] To this end, ECU 120 will request control module 118 to share output power between the HP axis and LP axis to supply load 116, which consumes the network's power L and typically exhibits variable dynamic range behavior, especially so-called active loads.

[0029] like Figure 2 As shown, the ECU requests this predetermined sharing of output power between the HP and LP axes. The ECU is initially in generator mode, for example, where 60% of the power L is output from the HP axis and 40% of the power L is output from the LP axis. To achieve the additional power required for the auxiliary request, the ECU can enter auxiliary mode, in which the high-voltage power output from the HP axis is interrupted, the high-voltage motor enters motor mode to inject high-voltage power, and then the LP axis supplies 100% of the power L, plus the load requested by the HP axis, as illustrated in the figure.

[0030] However, upon entering auxiliary mode, due to this instantaneous change in the power ratio, the transiently supplied power 130 deviates from the desired power 140. Therefore, the problem lies in finding a way to compensate for the difference between the transiently supplied power and the desired power from the remaining power source, thereby including the generated voltage within a predefined envelope until steady state is reached, without adding any external power source.

[0031] More specifically, this power difference in the transient state is expressed by the following formula (1):

[0032]

[0033] therefore,

[0034]

[0035] in

[0036] C: Value of the power capacitor on the DC bus

[0037] Ps: Power supply wattage

[0038] P1: Load power

[0039] Wc: Energy in the power capacitor

[0040] Since it is not feasible to increase the size of the capacitors in the power electronics, which would result in an oversized system design, nor is it feasible to accelerate the voltage and current control loops, which would involve limitations on the control circuitry (ECU cycle time, command delay, power electronics speed, etc.), this invention adds a function to regulate the generated voltage in the control module 118 to limit its variation during requests for assistance to the turbine engine and keep it within a range defined by the envelope. Quality is optimized because no external power source or oversized capacitors for the power electronics responsible for storing electrical energy are added.

[0041] Figure 3 The components forming the thus modified control module 118 are described in detail. This module further includes: a voltage regulation module 200 that delivers a predefined voltage envelope or the power P required to guarantee these envelopes; a mode generation module 202, connected thereto, receiving the power setpoint from the ECU 120 and coordinating the sharing of power of the load L between the HP and LP axes; and two associated auxiliary modules, one 204 associated with the high-voltage axis and the other 206 associated with the LP axis, configured to respectively direct the low-voltage P... LP or high voltage P HP Injected power is added to the remaining high voltage P HP or low pressure P LP The output power is selected from the mode generation module or the auxiliary module based on the power mode (MODE) from the ECU 120. LP and P HP Each auxiliary module includes adders 300 and 302 for quantifying the additional power generated on one side and the power output on the other side; and adaptive modules 304 and 306, which have transfer functions F1 and F2 that depend on the dynamic range of the associated motor.

[0042] For example, if the ECU requests negative power from the LP shaft (PLP in motor mode), then in order to calculate P... HP The adder subtracts the negative power P from the input power P to the auxiliary module 204. LP That is, since P LP The power of the load after entering motor mode is 100%. At the output terminal, P... HP Equals P+P LP .

[0043] Transfer functions F1 and F2 are used to adjust the dynamic range of the power output from the remaining machine to the dynamic range of the machine that has entered motor mode in order to predict its power demand. Depending on the specific situation, F1 and F2 can be equal to:

[0044] - If two machines mounted on the HP and LP axes have the same dynamic range, then F1 and F2 equal 1 (unity);

[0045] -If the dynamic range of the machine entering motor mode is slower than that of the machine remaining in generator mode, then F1 and F2 are phase delays or any function that can slow down the response of the remaining machine, such as a first-order transfer function.

[0046] -If the dynamic range of the machine entering motor mode is faster than that of the remaining machines, then F1 and F2 are phase advance functions.

[0047] Figure 4 The diagram illustrates the different steps of the method implemented in the control module.

[0048] In the first step 400, the system is in normal operation in generator mode, with output power shared between the high-voltage and low-voltage shafts. In the next step 402, a request is issued to operate in auxiliary mode; for example, the high-voltage motor (i.e., the motor driving the high-voltage shaft) that was in generator mode in normal operation mode (which is interrupted) enters motor mode. In the next step 404, the auxiliary module associated with the high-voltage shaft takes action to transmit high-voltage power to the low-voltage shaft, and then in the final step 406, the power output from the low-voltage shaft is adjusted based on this high-voltage power to achieve the additional power requested by the auxiliary mode.

[0049] It should be noted that regardless of the number of motors installed on the propulsion system or the type of turbine engine, such as a hybrid turbofan engine, a hybrid turboprop engine, or a hybrid helicopter turbine engine, this invention can be applied to the internal hybrid power of turbine engines.

Claims

1. A method for managing power transfer between a turbine engine (100) and an auxiliary mode, the turbine engine having a high-pressure shaft (102) driving a high-pressure motor (106) and a low-pressure shaft (104) driving a low-pressure motor (108), outputting high-pressure power (HP) from the high-pressure shaft and low-pressure power (LP) from the low-pressure shaft, the power generation mode corresponding to a predetermined power sharing between the high-pressure power and the low-pressure power, and the auxiliary mode corresponding to a request to inject additional power into the high-pressure shaft or the low-pressure shaft. Its features are, In order to achieve the requested additional power, when the high-voltage power or low-voltage power output is interrupted and the high-voltage motor or low-voltage motor that drives the interrupted high-voltage shaft or low-voltage shaft respectively enters motor mode, the remaining output power of the high-voltage shaft or low-voltage shaft in generator mode is adjusted based on the injected high-voltage power or low-voltage power from the high-voltage motor or low-voltage motor that has entered motor mode.

2. The method for managing power transfer according to claim 1, wherein if the high-voltage motor or the low-voltage motor has different dynamic ranges, the injection of the requested additional power is accomplished by adjusting the dynamic range of the remaining output high-voltage power or low-voltage power.

3. A turbine engine (100) comprising: a high-pressure shaft (102) and a low-pressure shaft (104), wherein high-pressure power (HP) is output from the high-pressure shaft and low-pressure power (LP) is output from the low-pressure shaft; a control module (118) receiving power setpoints from an ECU (120) and power converters (110, 112), the power converters being associated with a high-pressure motor (106) and a low-pressure motor (108) respectively mounted on the high-pressure shaft and the low-pressure shaft; a power generation mode corresponding to a predetermined power sharing between the high-pressure power and the low-pressure power; and an auxiliary mode corresponding to injecting additional power into the high-pressure shaft or the low-pressure shaft, characterized in that, In order to achieve the requested additional power, the control module (118) is configured such that when the output of high voltage power or low voltage power is interrupted and the high voltage motor or low voltage motor of the high voltage shaft or low voltage shaft whose output is interrupted enters motor mode, the remaining output power of the high voltage shaft or low voltage shaft in generator mode is adjusted based on the injected high voltage power or low voltage power from the high voltage motor or low voltage motor that has entered motor mode.

4. The turbine engine according to claim 3, wherein the control module further includes an auxiliary module (204, 206) and a selection module (208), the auxiliary module being configured to add injected high-pressure power or low-pressure power to the remaining output high-pressure power or low-pressure power, and the selection module being configured to select the output power from the auxiliary module.

5. The turbine engine according to claim 4, wherein each auxiliary module includes an adder (300, 302) and an adaptive module (304, 306), the adaptive module having transfer functions F1, F2, said transfer functions F1, F2 being used to adjust the dynamic range of the remaining output high-voltage power or low-voltage power according to the corresponding dynamic range of the high-voltage motor and the low-voltage motor.

6. The turbine engine according to claim 5, wherein if the high-voltage motor and the low-voltage motor have the same dynamic range, then the transfer functions F1 and F2 are both equal to 1.

7. The turbine engine of claim 5, wherein if the dynamic range of the motor entering electric motor mode is slower than the dynamic range of the motor remaining in generator mode, the transfer function is a phase delay.

8. The turbine engine of claim 5, wherein if the dynamic range of the motor entering electric motor mode is faster than the dynamic range of the motor remaining in generator mode, the transfer function is a phase advance function.

9. The turbine engine according to any one of claims 3 to 8, including an aircraft turbine engine.

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