Aircraft electric propulsion unit

Abstract

Aircraft electric propulsion unit. An aircraft electric propulsion unit (100) comprising: - a DC voltage source (110), - an electric motor (130) comprising four three-phase windings (131, 132, 133, 134), and - a power electronics and control device (150) connected to the DC voltage source and the electric motor, characterized in that the electric motor's power electronics and control device is multi-channel (151, 152, 153, 154) and in that the electric propulsion unit comprises four electrical channels (101, 102, 103, 104) formed, each, by a channel of the electric motor's power electronics and control device and one of the three-phase windings, the first and second electrical channels (101, 102) being configured to communicate with an aircraft control unit (120) and to send instructions for the third and fourth electrical tracks (103, 104),and in that the electric propulsion unit includes internal communication buses (161, 162) between each track. Figure for the abstract: Fig. 1,

Description

Title of the invention: Aircraft electric propulsion unit technical field

[0001] The present invention relates to the general field of aircraft electric propulsion systems, and more particularly to a redundant and reliable architectural solution for an electric propulsion unit. Previous technique

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

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

[0004] Consequently, the Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0005] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, in particular through the materials used and lighter on-board equipment, the development of the use of electrical technologies to provide propulsion, and, as essential complements to technological progress, aviation biofuels.

[0006] Electric or hybrid electric / thermal propulsion of conventional aircraft (CTOL), short takeoff and landing (STOL) aircraft, and vertical takeoff and landing (VTOL) aircraft is achieved by one or more electric motors. The conventional architecture of electric propulsion systems consists of a DC voltage source connected by power harnesses to a power electronics and control device, itself connected by power harnesses to an electric motor, itself connected to a propeller via a rotor, gearbox or other means of transmission.

[0007] Traditionally, the control of the electric motor actuation, i.e. the motor control unit (ECU), is divided into a control section and a monitoring section. The control section provides primary power control according to received instructions, as well as close protection for the physical components of the propulsion system.

[0008] The monitoring unit ensures the monitoring and safety of the propulsion system during feared events classified as dangerous. It can also inhibit the setpoint in the event of a confirmed fault requiring the system to be put into safety mode.

[0009] This type of control is therefore secure and may conflict with sufficient system availability.

[0010] Furthermore, the control of the electric motor actuation can be decomposed into a master part and a slave part, in which the master part gives instructions to the slave part. The slave part can take over the role of master if the latter fails by means of a secure master / slave authority switching mechanism.

[0011] In aeronautical applications, the power transmission chain consists of a DC voltage source, power electronics and electric motor control, and an electric motor driving a propeller. Power harnesses are present between the voltage source and the power electronics (DC power harness) and between the power electronics and the motor (three-phase power harness). In order to reduce weight and volume while ensuring the availability and reliability of the propulsion system and its power transmission, the power transmission chain is redundant with completely independent paths.Thus, each channel of the electric propulsion unit (or power transmission chain) includes a DC voltage source that can be common to several channels, power electronics connected to one of the motor windings, and suitable power harnesses between each component.

[0012] Another constraint related to the architecture of the transmission chain is the need for a dual control and communication interface with the rest of the aircraft (pilot, or aircraft global control unit, for example). In other words, two control units receiving two bidirectional communication buses carrying the same data must be able to communicate with the channels of the electric propulsion unit via an interface.

[0013] This interface must therefore be robust to simple failure and risks reducing the reliability of the whole.

[0014] It is therefore desirable to have a new architecture of the safe and redundant electric propulsion unit enabling repeatability, interchangeability and power balancing of the redundant channels. Description of the invention

[0015] To this end, the invention is the result of technological research aimed at significantly improving aircraft performance and, in this sense, contributes to reducing the environmental impact of aircraft. For this purpose, the invention relates to an aircraft electric propulsion unit comprising: - a direct current voltage source, - an electric motor configured to drive an aircraft propeller and comprising four three-phase windings, and - a power electronics and electric motor control device, the power electronics device being connected to the DC voltage source and the electric motor,

[0016] characterized in that the electric motor power electronics and control device is multi-channel and in that the electric propulsion unit comprises four electrical channels, each electrical channel being formed by one channel of the electric motor power electronics and control device and one of the three-phase windings of the electric motor, the first and second electrical channels being configured to communicate with an aircraft control unit external to the electric propulsion unit and to send instructions to the third and fourth electrical channels, and in that the electric propulsion unit includes internal communication buses between each channel.

[0017] Thus, the electric propulsion unit is formed of four tracks identical from a material point of view, which makes it possible to ensure the repeatability, interchangeability and power balancing of the tracks, and to reduce costs through the series production of the elements of these four tracks.

[0018] Moreover, from a software point of view and through the programming of the four channels, the channels do not have the same role: the first and second electrical channels form "master" channels, while the third and fourth electrical channels form "slave" channels.

[0019] The "master" channels can thus communicate with another aircraft control unit and receive instructions from that other control unit, for example, power / torque / speed instructions from the pilot, and send back centralized information from the electric propulsion unit. The "master" channels They also transmit power / torque / speed commands to the "slave" channels so that these channels can perform close control of their own channel, such as regulating the current according to the received command. Therefore, the "master" channels manage the electric propulsion unit and generate the individual commands for the "slave" channels.

[0020] The "slave" channels can only communicate with the "master" channels, and it is the "master" channels that centralize all the data at the level of the complete electric propulsion unit, for example sum of the torques or powers of the four electric channels.

[0021] According to a particular feature of the invention, each three-phase winding of the electric motor is configured in star.

[0022] The star connection of the three-phase windings allows for a greater number of possible electric motor control options.

[0023] According to another embodiment of the invention, each three-phase winding of the electric motor is mounted in delta.

[0024] According to a particular feature of the invention, the second electrical channel is configured to check the instructions sent by the first electrical channel and to replace the first channel in case of failure.

[0025] Thus the second electrical channel forms a so-called "master backup" channel. It allows monitoring of the first channel, in particular the commands generated by the first channel, and takes over if failures are detected on the first channel.

[0026] According to another particular feature of the invention, each electric track includes a control module comprising at least one processing unit configured to apply a setpoint and a monitoring module configured to monitor and secure the electric propulsion system in case of failure.

[0027] The command applied by the control module's processing unit comes from an aircraft control unit external to the propulsion unit or from another electrical channel; in other words, the processing unit is configured as a "master" or "backup master" (command coming from the external unit) or as a "slave" (command coming from another electrical channel). Each electrical channel thus performs control and monitoring of its own channel.

[0028] According to another particular feature of the invention, the control module of each electrical channel comprises two processing units, a first processing unit being configured to process the instructions received by its electrical channel, and a second processing unit being configured to perform control of its electrical channel.

[0029] The two processing units of each control module are separate processing units, and each has a distinct role: one processes the instructions received on the track, that is to say it will allow this instruction to be applied within the track, and the other allows for close control of the track.

[0030] According to another particular feature of the invention, each electrical channel includes a local communication bus between the two processing units of the communication module.

[0031] The processing unit configured to perform electrical track control can be connected to the internal communication buses, like the other monitoring and control modules, or it can use the local communication bus. The advantage of the local communication bus is that it is potentially faster.

[0032] According to another particular feature of the invention, the electric propulsion unit includes a synchronization bus between the control modules of the four electric channels.

[0033] The synchronization bus allows the control modules of the four tracks to be synchronized with each other. Indeed, in the event of a common voltage source for two or more electrical tracks, circulating currents can be established and cause disturbances, overheating, or even failures in the electric propulsion unit.

[0034] Another object of the invention is an aircraft comprising an electric propulsion unit according to the invention.

[0035] According to a particular feature of the invention, the aircraft is a vertical takeoff and landing (VTOL) aircraft or a short takeoff and landing (STOL) aircraft or a conventional aircraft (CTOL). Brief description of the drawings

[0036] Other features and advantages of the present invention will become apparent from the description given below, with reference to the attached drawings which illustrate examples of embodiment without any limiting character.

[0037] [Fig.1A] Fig.1A represents, schematically and partially, an electric propulsion unit according to an embodiment of the invention.

[0038] [Fig.1B] Fig.1B represents, schematically and partially, the electric propulsion unit of Fig.1A.

[0039] [Fig.2] Fig.2 represents, schematically and partially, a part of a a "master" track and a "slave" track of the electric propulsion unit according to another embodiment of the invention.

[0040] [Fig.3A] Fig.3A represents, schematically and partially, a part of a "master" track and a "slave" track of the electric propulsion unit according to another embodiment of the invention.

[0041] [Fig.3B] Fig.3B represents, schematically and partially, a part of a "master" track and a "slave" track of the electric propulsion unit according to another embodiment of the invention.

[0042] [Fig.4] Fig.4 represents, schematically and partially, a part of a "master" track and a "slave" track of the electric propulsion unit according to several embodiments of the invention. Description of the implementation methods

[0043] In the description, the term "power electronics" also means "power and control electronics".

[0044] Figures IA and IB schematically and partially represent an aircraft electric propulsion unit 100 according to a first embodiment of the invention. The unit 100 comprises a DC voltage source 110, an electric motor 130 comprising four three-phase windings 131, 132, 133, 134, and a power electronics device 150 for the motor 130.

[0045] The electric motor 130 is configured to drive a propeller 140 of the aircraft. The power electronics device 150 is connected to the DC voltage source 110 and to the electric motor 130 and is multi-channel 151, 152, 153, 154.

[0046] The electric propulsion unit 100 comprises four electrical paths 101, 102, 103, 104. Each electrical path 101, 102, 103, 104 is formed by a path 151, 152, 153, 154 of the power electronics device and one of the three-phase windings 131, 132, 133, 134 of the electric motor. The four paths 101, 102, 103, 104 are materially identical, which ensures repeatability, interchangeability, and power balancing of the four paths. This also reduces costs, as the components of these paths can be mass-produced.

[0047] However, from a software perspective, the four channels 101, 102, 103, 104 are different. The first 101 and second 102 electrical channels are configured to communicate with an aircraft control unit 120 external to the unit 100 and to send commands to the third 103 and fourth 104 electrical channels via internal communication buses 161, 162. External communication buses 171, 172 are connected to the first 101 and second 102 channels in order to exchange information (for example, if a channel has lost power, or if a channel is no longer operational), data (such as power, torque, speed, temperature, etc. data for each channel) and / or command signals (such as power, torque or speed commands) with the control unit 120.

[0048] In other words, the first 101 and second 102 channels are "master" channels, while the third 103 and fourth 104 channels are "slave" channels. The "slave" channels 103 and 104 can only communicate with other channels, whereas the "master" channels 101 and 102 can also communicate with the outside world. The "master" channels 101 and 102 can therefore provide the "slave" channels with command signals from another control unit 120 of the aircraft. These command signals could, for example, be a command from the aircraft pilot's actuation of the control stick.

[0049] The "master" channels 101, 102 manage the electric propulsion unit 100, perform the system functions, and generate the unit control signals for each channel, which are sent via the internal communication buses 161, 162. The "slave" channels 103, 104 then receive the control signals from the "master" channels and perform close control of their own channel, in particular of the inverter 193, 194 and its motor component 130, for example, regulating the electric current of the stator 183, 184 to match the torque required by the control signal. The "master" channels 101, 102 also perform close control of their own channel.

[0050] Each electrical track 101, 102, 103, 104 comprises a control module C0M1, COM2, COM3, COM4 and a monitoring module M0N1, M0N2, M0N3, M0N4. The control module C0M1, COM2, COM3, COM4 is supported by the monitoring module M0N1, M0N2, M0N3, M0N4, which acts to protect the track in the event of an inverter or motor fault not controlled by the control module C0M1, COM2, COM3, COM4. Thus, each electrical track 101, 102, 103, 104 is safe from the point of view of motor control.

[0051] The second electrical channel 102 can, more specifically, be a "backup master" channel. It is then configured to, in addition, monitor the first channel 101, that is to say, to check the instructions given by the first channel 101, and to replace it if anomalies or a failure are detected.

[0052] Fig. 2 represents, schematically and partially, part of a "master" channel and a "slave" channel of the electric propulsion unit according to a second embodiment of the invention, in particular channels 251 and 253 of the power electronics and control device of the electric motor.

[0053] Compared to Figures IA and IB, the external communication bus 271 is connected to the COM 12 control module and the MON 12 monitoring module of the "master" channel 251 of the power electronics device. The two internal communication buses 261 and 262 connect the COM32 control module and MON32 monitoring module of the "slave" channel 253 of the power electronics device to the C0M12 control module and M0N12 monitoring module of the "master" channel 251 of the power electronics device.

[0054] Figure 3A schematically and partially represents a portion of a "master" channel and a "slave" channel of the electric propulsion unit according to a third embodiment of the invention, in particular channels 351 and 353 of the power electronics and control device for the electric motor. An external communication bus 371 always allows the "master" channel 351 to communicate with an external unit of the aircraft, i.e., one other than the electric propulsion unit; and internal communication buses 361 and 362 always allow the various channels 351 and 353 to communicate with each other.

[0055] Compared to [Fig.2], the COM control module comprises two processing units COMal3, COMbl3, COMa33, COMb33. Thus, a third processing unit COMb13, COMb33 is used in each channel to separate the close control functions performed by the COM control module related to the motor and the management functions of the electric propulsion unit related to the functions of a "slave" or "master" channel.

[0056] In this embodiment, the first processing unit COMal3, COMa33 is connected to the same internal communication buses 361, 362 as the second processing unit COMbl3, COMb33 and monitoring unit M0N13, MON33.

[0057] Fig. 3B schematically and partially represents part of a "master" channel and a "slave" channel of the electric propulsion unit according to a fourth embodiment of the invention, in particular channels 351 and 353 of the power electronics and control device of the electric motor.

[0058] Compared to [Fig. 3A], a high-speed local communication bus 365 is present in channel 351 of the power electronics device, which belongs to a "master" channel, and another high-speed local communication bus 366 is present in channel 353 of the power electronics device, which belongs to a "slave" channel. These two high-speed communication buses 365 and 366 allow the two processing units COMal3, COMbl3 or COMa33, COMb33 of a COM control module to be connected to an electrical channel 351, 353. These high-speed communication buses 365, 366 are normally faster than the internal buses 361, 362 and are useful if the expected performance of the electric propulsion unit requires it.

[0059] Only two channels are shown in [Fig.3B], but it is obviously possible to add a local high-speed communication bus to the other channels of the electric propulsion unit.

[0060] Figure 4 schematically and partially represents a portion of a "master" and a "slave" channel of the electric propulsion unit according to several embodiments of the invention, in which a synchronization bus 481, 482, 483 is present between the different control modules COM41, COM43 of the channels. This synchronization bus allows for the synchronization of close-range controls, carried out For each electrical channel, inverters (motor windings) are connected in parallel on the same high-voltage DC power bus, which connects them to the power supply. Indeed, if at least two inverters share a common voltage source, circulating currents can develop between the inverter input stages, causing disturbances, overheating, or even failures. Synchronization buses are used so that the "master" channels send a synchronization signal to the "slave" channels. It is possible to add redundancy to this synchronization bus between each "master" and "slave" channel to improve the availability and operational reliability of the electric propulsion unit.

[0061] In Figure 4A, which reproduces the embodiment of [Fig. 2], the synchronization bus 481 connects the control modules COM41 and COM43 of channels 451 and 453 of the power electronics. The remaining communication between the two channels 451 and 453 is always carried out using the internal communication buses 461 and 462.

[0062] In Figure 4B, which reproduces the embodiment of [Fig. 3A], the synchronization bus 482 connects the COMb41 and COMb43 processing units, dedicated to the close monitoring of the electrical channel, to the power electronics channels 451 and 453. The remaining communication between the two channels 451 and 453 is always carried out using the internal communication buses 461 and 462.

[0063] In Figure 4C, which reproduces the embodiment of [Fig. 3B], the synchronization bus 483 connects the COMb41 and COMb43 control modules of the power electronics channels 451 and 453. The remaining exchanges between the two channels 451 and 453 are always carried out using the internal communication buses 461 and 462; and communication between the two processing units COMa41, COMb41 or COMa43, COMb43 of the COM control module within each electrical channel is always carried out via the high-speed communication buses 465 and 466.

[0064] For reasons of simplicity and clarity of the figures, only two electrical paths, a "master" and a "slave", are shown in figures 2, 3A, 3B, and 4, but the embodiments illustrated are obviously applicable to all four electrical paths of the electric propulsion unit.

[0065] Regardless of the embodiment of the invention, the windings of the electric motor are configured in a star configuration.

[0066] Regardless of the embodiment of the invention, the "master" channels can also be configured to take into account the voltage value specific to each electrical channel in order to adjust power output according to the state of charge of the DC voltage source (which may be a battery). This makes it possible to compensate for differences in state of charge due to a different state of aging or health between the batteries.

[0067] Regardless of the embodiment of the invention, the control and monitoring modules do not use the same sensors to ensure a level of independence and segregation guaranteeing the overall safety level required for aeronautical standards.

[0068] Regardless of the embodiment of the invention, the management of fault cases of the electric propulsion unit can be done in the following manner.

[0069] If the fault involves a control module, the affected channel becomes non-operational, and the electric propulsion unit then considers that there are only three channels. The power, speed, etc., commands are therefore calculated for three channels instead of four.

[0070] If the fault involves a monitoring module, the affected channel loses its monitoring function, thereby reducing the operational safety margin of the electric propulsion unit. If this loss of monitoring function is acceptable from an operational safety standpoint, or is not detected, the propulsion unit continues to operate with four electrical channels. If the loss of monitoring function is detected and is unacceptable from an operational safety standpoint, then the affected channel becomes a non-operational channel, as in the previous case.

[0071] If the fault involves a "master" channel and / or a processing module of a "master" channel, the other "master" channel (or the "backup master" channel) will take over the function of the faulty channel (the "backup master" channel becomes the "master" channel, for example). Furthermore, the propulsion unit abandons this channel, and another "slave" or "master" channel will take over control of the faulty channel.

[0072] If the fault concerns a "slave" channel and / or a processing module of a "slave" channel, the propulsion unit abandons this channel and another "slave" or "master" channel will take over control of this faulty channel.

[0073] The electric propulsion unit according to the invention may, for example, belong to a conventional aircraft (CTOL) or to a vertical takeoff and landing (VTOL) aircraft or to a short takeoff and landing (STOL) aircraft.

[0074] The invention also relates to an aircraft comprising an electric propulsion unit according to the invention.

Claims

Demands

1. An aircraft electric propulsion unit (100) comprising: - a DC voltage source (110), - an electric motor (130) configured to drive an aircraft propeller (140) and comprising four three-phase windings (131, 132, 133, 134), and - a power electronics and control device (150) for the electric motor, the power electronics device being connected to the DC voltage source and the electric motor, characterized in that the power electronics and control device for the electric motor is multi-channel (151, 152, 153, 154, 251, 253, 351, 353, 451, 453) and in that the electric propulsion unit comprises four electrical channels (101, 102, 103, 104), each electrical channel being formed by one channel of the device of power electronics and control of the electric motor and one of the three-phase windings of the electric motor, the first and second electrical paths (101,102) being configured to communicate with an aircraft control unit (120) external to the electric propulsion unit and to send instructions to the third and fourth electrical channels (103, 104), and in that the electric propulsion unit includes internal communication buses (161, 162, 261, 262, 361, 362, 461, 462) between each channel.

2. Electric propulsion unit according to claim 1, wherein each three-phase winding of the electric motor is star-configured.

3. Electric propulsion unit according to any one of claims 1 or 2, wherein the second (152) electric channel is configured to check the instructions sent by the first (151) electric channel and to replace the first electric channel in case of failure.

4. Electric propulsion unit according to any one of claims 1 to 3, wherein each electric channel (101, 102, 103, 104) comprises a control module (COM1, COM2, COM3, COM4, ​​COM12, COM32, COM13, COM33, COM) including at least one processing unit configured to apply a setpoint and a monitoring module (M0N1, M0N2, M0N3, M0N4, M0N12, MON32, M0N13, MON33, M0N41, MON43) configured to monitor and secure the electric propulsion system in case of failure.

5. Electric propulsion unit according to any one of claims 1 to 4, wherein the control module (COM) of each electric track comprises two processing units (C0Mal3, C0Mbl3, COMa33, COMb33, C0Ma41, C0Mb41, COMa43, COMb43), a first processing unit (C0Mal3, COMa33, C0Ma41, COMa43) being configured to process the instructions received by the electric track and a second processing unit (C0Mbl3, COMb33, C0Mb41, COMb43) being configured to perform control of its electric track.

6. Electric propulsion unit according to claim 5, wherein each electric channel comprises a local communication bus (365, 366, 465, 466) between the two processing units (COMal3, COMMbl3, COMa33, COMb33, COMMa41, C0Mb41, COMa43, COMb43) of the control module (COM).

7. Electric propulsion unit according to any one of claims 4 to 6, comprising a synchronization bus (481, 482, 483) between the control modules (C0M41, COM43, C0Mb41, COMb43) of the four electric channels.

8. Electrically powered or hybrid thermal / electric powered aircraft comprising an electric propulsion unit according to any one of claims 1 to 7.

9. Aircraft according to claim 8, wherein the aircraft is a vertical takeoff and landing (VTOL) aircraft or a short takeoff and landing (STOL) aircraft or a conventional (CTOL) aircraft.

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