SMART ELECTRIC MOTOR WITH ELECTRICAL REDUNDANCY AND INTEGRATED FAULT DETECTION

Abstract

Intelligent motor (10) comprising: - an electromechanical permanent magnet converter (12); and - an electronic control unit; the electromechanical converter (12) comprising: - a permanent magnet rotor (121); and - a stator (122) comprising: - a first assembly comprising at least three phases electrically connected to each other in a star configuration; - a second assembly comprising as many phases as the first assembly, the phases of the second assembly being electrically connected to each other in a star configuration; and - an impedance between the neutral points of the stars of the first and second assemblies; said electronic control unit (18) comprising a control inverter, comprising as many independent control arms as there are phases of the first assembly and as many independent control arms as there are phases of the second assembly;the control inverter being configured to drive each phase of the first set and each phase of the second set by its own control arms; the electronic control unit being configured to measure a voltage difference between neutral points of the stars of the first and second sets with respect to a voltage reference common to said sets.

Description

Title of the invention: INTELLIGENT ELECTRIC MOTOR WITH ELECTRICAL REDUNDANCY AND INTEGRATED FAULT DETECTION technical field

[0001] The present exposition relates to an intelligent electric motor, in particular for an aircraft, and more particularly to the electrical architecture of an intelligent electric motor with multiple electrical channels, with integrated fault detection in order to enhance its operational safety. State of the art

[0002] The electric motor has recently become interesting in vehicular applications, and in particular aerospace, to promote the low carbon footprint associated with its use, its flexibility of implementation, its efficiency (only the necessary energy is consumed), its reliability (limited maintenance) and also the potential reduction in mass and volume that it generates compared to a conventional propulsion system (thermal with hydraulic or pneumatic energy distribution).

[0003] It is then easy to understand that the mechatronic integration constraints (mass and volume) of the electric motor assembly, controller (power electronics and control electronics), filtering and cooling system and the operational safety are a key issue of this change, in particular to obtain a propulsion assembly whose mass and size remain low.

[0004] An architecture for a smart motor with a gearbox and a plurality of independent windings is known. Each winding is powered by an H-bridge converter, but the input filtering is not integrated into the smart motor. Consequently, the architecture is relatively bulky. Furthermore, the presence of a gearbox in the smart motor reduces the motor's reliability and / or leads to an increase in scheduled maintenance operations, compared to a smart motor without an integrated gearbox.

[0005] A smart motor is also known, comprising two groups of three coils electrically connected in a star configuration, with the neutrals of the two groups electrically connected to each other to have a common electrical point and balance the currents. This configuration is relatively inexpensive to manufacture. However, this configuration allows a failure in one of the groups to disrupt the operation of the other group.

[0006] French patent FR 3089715 discloses a motor whose stator comprises two sets three-phase systems that are electrically decoupled from each other. The purpose of the following discussion is to demonstrate that, on the contrary, a well-designed electrical coupling can improve the ability to detect faults or anomalies in the behavior of the stator assemblies. Purpose of the presentation

[0007] The present exposition aims to provide an intelligent motor architectural solution enabling the supply of mechanical torque even in the event of a (total or partial) failure of a voltage inverter arm of a star of a stator or in the event of a failure of an entire star of the stator, and also enabling the detection of a failure in one of the stars of its stator.

[0008] Each given control arm of the inverter drives only one phase of a single set.

[0009] In the first part of this exposition, an intelligent motor is proposed, comprising a permanent magnet electromechanical converter and an electronic control unit. The electromechanical converter comprises a permanent magnet rotor and a stator. The stator comprises a first assembly, including at least three phases electrically connected to each other in a star configuration, a second assembly, including the same number of phases as the first assembly, the phases of the second assembly being electrically connected to each other in a star configuration, and an impedance between the neutral points of the stars of the first and second assemblies. The electronic control unit comprises a control inverter, including as many independent control arms as there are phases in the first assembly and as many independent control arms as there are phases in the second assembly.The control inverter is configured to drive each phase of the first set and each phase of the second set with its own control arms. The electronic control unit is configured to measure a voltage difference between the neutral points of the stars of the first and second sets relative to a voltage reference common to said sets.

[0010] The electrical coupling of the neutral points of the stars in the first and second sets, and the voltage measurement between them, allows the motor to detect a fault (total or partial short circuit, break in a motor phase, conductor degradation, open circuit, loss of a transistor in an open circuit, open failure, etc.) in the stator. If the fault is detected early enough, it is even possible to change the motor's operation to avoid overheating of the motor and / or damage to its components (for example, stator conductors).

[0011] Impedance can help not only to generate a voltage difference when a current exists between the neutral points of the assemblies, but also to limit this current. The electronic control unit can be configured to measure the voltage at impedance limits.

[0012] In the intelligent motor described above, the two star-connected sets can be wound successively rather than simultaneously. This takes longer than simultaneous winding but allows for magnetic and / or electrical decoupling, and / or allows for mechanical segregation of the coils of the two sets. The balancing of the torques produced by the controlled currents is achieved by winding each set of coils separately. The winding must therefore be more complex than in the configuration where the two sets of coils are wound simultaneously (because two independent windings are created, instead of a single winding with two wires electrically insulated from each other).

[0013] In the intelligent motor described above, the coils of the different assemblies can be distributed around the axis of rotation of the intelligent motor's rotor so as to be geometrically separated from one another. This geometric separation, in other words, mechanical segregation, can limit or even prevent the propagation of a fault in one of the assemblies to another via electrical conduction and / or induction and / or heat transfer.

[0014] The motor can be configured to isolate the first and second sets from each other in response to an exceedance of a voltage threshold by the voltage between the neutral points of their stars.

[0015] Thus, the faulty assembly would no longer be controlled when the motor continues to control the non-faulty assembly.

[0016] The motor can be configured to measure the voltage at each terminal of each phase of the first and second sets, and to signal a fault in the given sets in response to an exceedance of a divergence threshold by a difference between the voltages of two of its phases. Alternatively, the motor can be configured to measure the voltage at each terminal of each phase of the first and second sets, and the current of each coil supply, to locate a fault in one of the given sets in response to an exceedance of a voltage threshold by the voltage between the neutral points of the star connections of the first and second sets.

[0017] Thus, the motor can identify which assembly would be faulty, even when the stator comprises only two assemblies. However, the motor can be configured in this way regardless of the number of assemblies in the stator.

[0018] The stator may include at least one assembly other than the first and second assemblies, each comprising as many phases as the first assembly, electrically connected to each other in a star configuration. The inverter may further include as many independent control arms as there are phases in the assembly(ies) other than the first and second assemblies. The inverter may be further configured to drive each phase of the (set of) set(s) other than the first and second sets by its own control arm. The electronic control unit can be further configured to measure a voltage difference between the neutral point of the star of the first set and the neutral point of the star of (one of) the set(s) other than the first and second sets, and to measure a voltage difference between the neutral point of the star of the second set and the neutral point of the star of (one of) the set(s) other than the first and second sets.

[0019] When the intelligent motor has more than two sets, it can at least measure the voltage difference between a neutral point of one of the sets and those of two other sets, or even measure the voltage difference between the neutral points of all the sets taken two by two.

[0020] The intelligent motor can be housed without a gearbox inside its casing, the casing, or housing, containing the electromechanical converter and the control unit. This can result in a reduction in size and weight, as well as improvements in reliability and maintenance.

[0021] The electromechanical converter can be a synchronous machine.

[0022] The stator of the electromechanical converter may comprise a series of teeth arranged circumferentially around the stator. For example, the series of teeth may be implemented as a toothed ring and / or a stack of laminations having radial projections separated circumferentially by radial notches. Each phase may comprise a coil wound around a single tooth of the stator, or a series of several coils wound around a single tooth of the stator. "Stator tooth" means a tooth of a toothed ring or a radial projection of a stack of laminations.

[0023] Thus, each of the coils of each of the assemblies can be wound around a single tooth of the toothed ring, which can minimize the size of the stator, in particular the size of the coil head.

[0024] The rotor may include magnets arranged in a Halbach configuration (“Halbach array” in English) which may increase the torque mass of the intelligent motor.

[0025] The stator of the electromechanical converter can be divided into distinct angular ranges, the number of angular ranges of a stator corresponding to the number of three-phase sets of the stator, the angular range extending over an angle corresponding to the result of dividing 360° by the number of sets of the stator, or by an integer multiple of the number of sets of the stator.

[0026] In the case of a stator with two sets, the coils of the first set would thus be arranged over a first angular range of the stator extending over 180° mechanical and coils of the second set could be arranged on a second angular range of the stator extending over 180° mechanical, the first angular range being distinct from the second range.

[0027] The first set of coils and the second set of coils are therefore located on two distinct parts of the perimeter of a circle. This can facilitate mechanical, magnetic, electrical and / or thermal segregation between the two sets of coils, in particular to prevent a defect possibly present on a coil of one of the sets from propagating to, and / or damaging, a part of another set.

[0028] The control unit may further include a current regulation module in each set of coils independently of the other set of coils, and / or a rotor speed regulation module.

[0029] The control unit can be configured to operate with and / or without a mechanical rotor position sensor. The mechanical position sensor can provide the angular mechanical position of the rotor (relative to the stator) to which the sensor is connected. This allows the control unit to have this position information to regulate the currents in the two sets of stator windings. If the motor is equipped with a rotor position sensor, this sensor may have a measuring channel that is used by all sets—or one sensor per set.

[0030] When the position sensor is not mounted or when the position information from the sensor is lost, a position estimation method can be implemented by the control unit's regulation module to ensure the current regulation function in the two stator windings.

[0031] The electronic control unit may advantageously further include a connection interface connecting a high-voltage DC power supply bus to each of the inverter arms and comprising a capacitive decoupling stage equipped with differential mode capacitors. List of drawings

[0032] Other features and advantages of the technology described herein will become apparent from the following description of several embodiments of the technology described herein, given by way of example and with reference to the attached drawings.

[0033] [Fig-1] Figure [Fig.1] schematically presents a multi-rotor aircraft propulsion equipped with an electric propulsion system according to an embodiment.

[0034] [Fig.2] Fig.2 schematically represents a fixed-wing aircraft and several propulsion rotors equipped with an electric propulsion system according to one embodiment.

[0035] [Fig.3] Fig.3 schematically represents a cross-sectional view of an intelligent motor of the propulsion system of [Fig.1] according to a first embodiment of the intelligent motor.

[0036] [Fig.4] The [Fig.4] is a schematic representation of a circumferential arrangement of two sets of at least three phases.

[0037] [Fig.5] The [Fig.5] is a schematic representation of a circumferential arrangement of two sets of at least three phases.

[0038] [Fig.6] The [Fig.6] is a schematic representation of a circumferential arrangement of two sets of at least three phases.

[0039] [Fig.7] The [Fig.7] is a schematic representation of the electrical architecture, according to a first embodiment, of the electromechanical converter of the intelligent motor of the [Fig.3].

[0040] [Fig.8] Fig.8 schematically presents an electrical architecture, according to a second embodiment, of the electromechanical converter of the intelligent motor of Fig.3.

[0041] [Fig.9] Fig.9 schematically presents an electrical architecture, according to a third embodiment, of the electromechanical converter of the intelligent motor of Fig.3. Detailed description of the invention

[0042] Figure 1 schematically shows an aircraft with several propulsion rotors 7 equipped with a propulsion system 9 according to one embodiment. In the example illustrated in Figure 1, the propulsion system 9 comprises four propulsion rotors 1 to 4 distributed on a circle (propulsion rotors shown in dashed lines) arranged concentrically around a center of symmetry 8. The propulsion rotors 1 to 4 form two pairs of propulsion rotors. The propulsion rotors within each pair of propulsion rotors are symmetrically opposite with respect to the center of symmetry 8. The first pair of propulsion rotors comprises rotors 1 and 4, and the second pair of propulsion rotors comprises rotors 2 and 3. It is also envisaged to provide for more than four rotors. As can be seen in Figure 1, the propulsion system 9 comprises four propulsion rotors 1 to 4 distributed on a circle (propulsion rotors shown in dashed lines) arranged concentrically around a center of symmetry 8.[l], in the case of eight rotors 1, la, 2, 2a, 3, 3a, 4, 4a, rotors 1, 2, 3, and 4 are grouped respectively with rotors la, 2a, 3a, and 4a, with rotors la and 4a symmetrically opposite with respect to the center of symmetry 8, and rotors 2a and 3a symmetrically opposite with respect to the center of symmetry 8. Furthermore, the propulsion system 9 includes an intelligent motor for each propulsion rotor 1, la, 2, 2a, 3, 3a, 4, 4a. It is also envisaged for the aircraft 7 to include a single pair of propulsion rotors, or exactly three pairs of propulsion rotors, or at least four pairs of propulsion rotors. Moreover, the intelligent motor 10. disclosed herein could also be used in a single-engine propulsion aircraft or in an aircraft having an even or odd plurality of propulsion engines.

[0043] While the propulsion rotor arrangement visible in [Fig.1] is suitable for vertical takeoff and landing and / or rotary-wing applications, [Fig.2] schematically represents a fixed-wing aircraft 7a, with one, two, three, four, five, or even more propulsion rotors 1, 2, 3, ..., X1, X. Each engine can be identical to one of the engines visible in [Fig.1].

[0044] A person skilled in the art will understand that an engine according to the exposition could be used in any propulsive / motor or non-propulsive application, in any aircraft / vehicle or non-vehicular machine.

[0045] In the case of an application with access to ground—for example, a non-flying machine—the common voltage reference for the intelligent motor assemblies is ground. In the case of an application without access to ground—for example, in an aircraft—the common voltage reference for the intelligent motor assemblies is the reference voltage used in the aircraft's (or other application's) electrical system(s).

[0046] Figure 3 schematically represents a cross-sectional view of an intelligent motor 10 according to a first embodiment

[0047] The intelligent motor 10 illustrated in [Fig. 3] comprises an electromechanical converter 12 having a rotating part defining an axial direction DA and a radial direction DR. [Fig. 3] is a cross-sectional view along a plane comprising the axial direction DA and the radial direction DR.

[0048] A transmission shaft 13 is disposed towards a first end 201 of the motor 10 in the axial direction DA.

[0049] The intelligent motor 10 includes a paddle wheel 14 mounted on a cooling rotor 9 surrounding a cooling stator 99. The cooling rotor 9 and the cooling stator 99 are arranged towards a second end 202 of the intelligent motor 10 in the axial direction DA.

[0050] The intelligent motor 10 includes electrical filtering means 16, an electronic control unit 18, and a housing 20, or casing inside which are housed the electromechanical converter 12, the electronic control unit 18 and the filtering means 16.

[0051] The housing 20 has a hollow, substantially cylindrical or frustoconical shape, with, in the embodiment illustrated in [Fig. 3], a circular cross-section. The axis of revolution of the housing 20 can coincide with the axis of rotation of the electromechanical converter 12, which coincides with the axis of rotation of the transmission shaft 13.

[0052] The axis of rotation of the transmission shaft 13 can be confused with the axis of rotation of the paddle wheel 14.

[0053] In the axial direction DA, the casing 20 is closed towards the first end 201 by a cover 22, and towards the second end 202 by the paddle wheel 14.

[0054] The intelligent motor 10 includes a cooling device 24 which cooperates with the impeller 14 and the casing 20 to cool the various components of the intelligent motor 10 and in particular the electromechanical converter 12.

[0055] The cooling device 24 includes a cooling housing 245 disposed around the housing 20, thus defining a cooling channel 248 disposed radially between an external radial surface 203 of the housing 20 and an internal radial surface of the cooling housing 245. The terms "internal" and "external", and "inside" and "outside" are used here with reference to the radial direction DR in the intelligent motor 10.

[0056] The rotation of the impeller 14 generates and supplies an airflow F into the cooling channel 248. As an example, the flow can enter the channel 248 through the second end 202 of the intelligent motor 10, passing through the blades 140 of the impeller 14, and can exit the channel through the first end 201 of the intelligent motor 10, passing through the cover 22.

[0057] The cooling device 24 comprises a set of fins 240 extending radially outwards from the external radial surface 203 of the housing 20, at a position in the axial direction DA between the first 201 and second 202 ends. The fin assembly 240 forms a radiator enabling heat exchange between the fins 240 and an airflow F passing through the fins 240 of the cooling device 24. In this case, the fin assembly is located at the stator 122 of the intelligent motor 10, and thus allows the stator 122 to be cooled.

[0058] In one embodiment, the intelligent motor might not include blades and a cooling casing in order to reduce its mass. The intelligent motor would then be cooled by the airflow generated by the aircraft's propulsion rotor, the propulsion rotor conventionally consisting of a propeller mechanically linked to the intelligent motor's rotation shaft. In another embodiment, the intelligent motor might include a blade directly driven by the shaft 13, without the need for cooling rotor torque and a cooling stator.

[0059] In the embodiment illustrated in [Fig. 3], which represents an "axial" configuration of the intelligent motor 10, the intelligent motor 10 comprises a housing 20 including a cooling device 24, a drive unit including the electromechanical converter 12 and the transmission shaft 13, an electronic unit including, in particular, the electrical filtering means 16 and the unit of control 18. The electronic part is arranged between the electromagnetic converter 12 and the second end 202, for example between the paddle wheel 14 and the driving part in the axial direction DA.

[0060] The driving part is supported in the housing 20 by a conical structure 98 extending axially towards the second end 202 from the first end 201 and radially from the shaft 13 towards an internal radial surface 204 of the housing 20. At the shaft 13, the structure 98 includes one or more bearings 97A, 97B.

[0061] Structure 98 separates the motor part and the electronic part. However, as seen in [Fig.3], structure 98 may include one or more perforations to reduce its weight.

[0062] The intelligent motor 10 comprises an inner wall 15 extending axially towards the first end 201 from the cooling stator 99 and radially from the cooling stator 99 towards the internal radial surface 204 of the housing 20. A first portion 15A of the inner wall 15 is fixed to the internal radial surface 204 of the housing 20 and surrounds a disk, extending radially in the axial direction DA. A second portion 15B of the inner wall 15 is located inside the cooling stator 99 and fixed to the first portion 15A of the inner wall 15. The electromechanical converter 12 is located inside the housing 20 downstream of the first portion of the inner wall 15. The electrical filtering means 16 and the electronic control unit 18 of the electronic part are located upstream of the electromechanical converter 12.The terms "upstream" and "downstream" are used here in reference to the direction of flow of the cooling airflow represented by arrow F in [Fig.3].

[0063] The electronic control unit 18 includes a static electrical converter 180 configured to power the electromechanical converter 12.

[0064] The electrical converter 180 is fixed to the first part 15A of the inner wall 15, and disposed between the disk and the second end 202.

[0065] The electrical converter 180 comprises, in the embodiment illustrated in [Fig.3], six electronic power units 1800 arranged together on the first part 15A of the inner wall 15 to form a hollow cylinder with a hexagonal base coaxial with the shaft 13.

[0066] In a variant where the electrical converter would comprise three, four, five, seven, or eight - or even more - 1800 power electronic units, they would form a regular polygon coaxial with the shaft 13. If it comprised two 1800 power electronic units, they would be on either side of the shaft, and coplanar with its axis of rotation.

[0067] The intelligent motor 10 comprises as many cooling devices 25 as there are electronic power units 1800. The cooling devices 25 are arranged on the first part 15A of the inner wall, in the same position in the axial direction DA as the electronic power units 1800, so that their fins extend into the vein 248.

[0068] The filtering means 16 include an electronic filtering board 160 on which capacitors 162 are mounted. The electronic filtering board 160 is fixed to the disk, and disposed between the disk and the structure 98.

[0069] In the embodiment illustrated in [Fig.3], the capacitors 162 are arranged to create a polygonal shape allowing them to be interposed between the housing 20 and the shaft 13. The same applies when the motor 10 includes two capacitors (diametrically opposed with respect to the axis of rotation of the shaft 13), or three, four, five, six, seven, eight, or more (regular polygonal shapes coaxial with the shaft 13).

[0070] In addition, the electronic control unit 18 includes an electronic control board 182 configured to control the operation of the electromechanical converter 12.

[0071] The intelligent motor 10 includes a supervisory electronic board 26 housed inside the casing 20 and in communication with the control electronic board 182. The supervisory electronic board extends in a radial plane comprising the radial direction DR and orthogonal to the axial direction DA. The supervisory electronic board 26 is positioned opposite the second part 15B of the inner wall 15, between the electrical converter 180 and the second part 15B of the inner wall 15.

[0072] In this axial configuration, the cooling device 24 is shared between the electromechanical converter 12 and the electronic part of the intelligent motor 10 (for example, between the electromechanical converter 12, the filtering means 16, and the electronic control unit 18). The cooling airflow F delivered by the vanes 140 of the impeller 14 flows along the external radial surface 203 of the housing 20 and communicates fluidically with the fins of the cooling devices 24, 25. The housing 20 recovers both the heat generated by the electromechanical converter 12 and the heat generated by the electronic part, in particular by the power converter 180, and transfers the heat to the cooling airflow F, notably via the cooling devices 24, 25. The airflow F then removes the heat from the intelligent motor 10.

[0073] The electromechanical converter 12 of the intelligent motor 10 can be a synchronous machine. The electromechanical converter 12 comprises a permanent magnet rotor 121 and a stator 122. As illustrated in [Fig.7], the stator has a first set 123 of at least three phases, whose coils 1230 are electrically connected in a star configuration, and a second set 124, with the same number of phases as the first set 123, and whose coils 1240 are electrically connected in a star configuration.

[0074] The electronic control unit 18 of the intelligent motor 10 includes a control inverter 184 equipped with as many independent control arms 1840 as there are phases of the stator of the electromechanical converter. Each control arm 1840 is configured to drive a phase 123, 124 of the stator 122 of the electromechanical converter 12. The inverter 184 is configured to drive each phase of the stator by its own control arm.

[0075] To ensure mechanical segregation between the stator assemblies 123, 124, the coils 1230 of the first assembly 123 are wound and then the coils 1240 of the second assembly 124 can be wound after the winding of the coils 1230 of the first assembly 123.

[0076] The stator 122 includes a toothed ring. Each coil 1230, 1240 of the stator can be wound around a single tooth of the toothed ring, which allows minimizing the size of the stator 122, in particular the size of the head of each of the coils 1230 and 1240, or of a series succession of several coils each wound around a single tooth of the toothed ring.

[0077] The rotor 121 includes magnets arranged in a conventional radial configuration or a Halbach configuration to increase the torque mass of the intelligent motor 10.

[0078] When the motor 10 comprises only two sets 123, 124, the coils 1230 of the first set 123 can be arranged on a first angular range PI of the stator extending over 180° mechanically, and the coils 1240 of the second set 124 can be arranged on a second angular range P2 of the stator extending over 180° mechanically. Such an arrangement of the angular ranges is illustrated schematically in [Fig. 4]. The first angular range PI is distinct from the second angular range P2, each angular range PI, P2 thus covering a semicircle, in order to minimize - or even avoid - the magnetic coupling of the phases of different sets 123, 124, and / or to ensure mechanical segregation / geometric separation of the phases of different sets 123, 124. More generally, when the motor comprises N sets, there would be N distinct angular ranges each extending over (360 / N)° mechanical and collectively forming a circle.As an example, N can be an integer equal to or greater than three.

[0079] It is also envisaged to provide several angular ranges per set. For example, in [Fig. 5], the angular ranges Pla, Pib, P2a, P2b each extend over 90° mechanically and are arranged so that the ranges Pla and Pib, which correspond to the first set, are interspersed with the ranges P2a and P2b, which correspond to the second set. [Fig. 6] represents a similar arrangement of three angular ranges Pla, Pib, Pic corresponding to the first set interspersed with three angular ranges P2a, P2b, P2c corresponding to the second set. Each of the six ranges spans 60° mechanically. More generally, when M ranges are provided for each set, they each span (180 / M)°, such that the ranges corresponding to the first set and the ranges corresponding to the second set collectively form a circle. As an example, M can be an integer equal to or greater than three.

[0080] More generally, a range can extend over (360 / (N*M))° mechanical, where N is the number of sets and M is the number of ranges per set.

[0081] The electronic control unit 18 includes a current regulation module in each assembly 123,124 independently of the other (or independently of the other) assembly(ies) 124, 123, and a rotor speed regulation module 121.

[0082] The intelligent motor 10 includes a connection interface linking a high-voltage DC power bus to each of the arms 1840 of the inverter 184 of the electronic control unit 18. The connection interface includes filtering means 16 implemented as a capacitive decoupling stage equipped with differential-mode capacitors. In the embodiment illustrated in [Fig. 3], the connection interface is combined with the filtering electronic board 160.

[0083] The electronic control unit 180 is configured to measure a voltage difference between the neutral point of the star connection of the first set 123 and the neutral point of the star connection of the second set 124. To this end, the motor 10 may include an impedance Z12 (for example, a resistor, capacitor, inductor, or a combination thereof) electrically coupling the neutral points of the stars of the first 123 and the second 124 sets, and the electronic control unit 180 may be configured to measure the voltage VD12 across this impedance. The introduction of an impedance Z12 between the neutral points limits the current between the stars of the sets. The impedance Z12 may be connected directly to the stator conductors, or indirectly to the stator conductors via wires or other conductors.

[0084] In general, when two identical sets are driven in the same way, the sets are expected to behave identically. A deviation in their behavior, which typically signifies a problem with one or the other set when driven identically, can be detected by the presence of a voltage difference VD12 between the neutral points of their stars, exceeding a predetermined voltage threshold. The predetermined voltage threshold is greater than the normal voltage variations that can exist when the identically driven sets behave identically.

[0085] The motor 10 can be configured (for example at the level of its electronic control unit 180) to isolate the first 123 and second 124 sets from each other when it detects that this voltage difference VD12 exceeds the pre-voltage threshold determined. For example, the predetermined threshold may correspond to a deviation in behavior beyond which a wire break or open-mode failure of the bridge arm supplying a coil, a circuit open, an open-circuit transistor loss, a short circuit and / or significant conductor degradation could occur in a given assembly, or even an assembly failure, would generate a signal beyond the threshold, thus signaling the fault.

[0086] By way of example, in the context of an aircraft propulsion engine, the neutral point voltages of the two sets may differ by about 7 volts or less, whereas a fault in one of the sets would cause a difference of about 30 to 50 volts, or even more. The threshold can then be defined as being between 7 and 50 volts, or between 7 and 30 volts, or between 10 and 30 volts, or between 13 and 25 volts, or between 13 and 20 volts, or between 13 and 17 volts. A relatively low threshold can allow faults to be detected earlier in their development, while a relatively high threshold can help rule out false alarms. Those skilled in the art will understand that such threshold ranges can also be used in contexts other than aircraft.

[0087] The motor 10 can continue to use the non-failing assembly to drive the shaft 13.

[0088] Figure 8 schematically presents an electrical architecture according to a second embodiment of the motor shown in Figure 3. This architecture differs from that shown in Figure 7 by the presence of more than two assemblies in the stator 122.

[0089] When the motor 10 comprises more than two sets (each having as many phases as the first set 123), the neutral point of the star of the first set 123 is also electrically coupled to the neutral point of a star of a set other than the second set 124, the electronic control unit is configured to measure a voltage difference between the neutral points of the stars of the first set 123 and of this other set than the second set, the neutral point of the star of the second set 124 is electrically coupled to the neutral point of a star of a set other than the first set 123, and the electronic control unit is configured to measure a voltage difference between the neutral points of the stars of the second set 124 and of this other set than the first set.

[0090] For example, in [Fig. 8], where the stator has three sets, of which the third 125 has the same number of phases (and coils 1250) as the first 123, the star neutral point of the third set 125 is electrically coupled to the star neutral points of the first 123 and second 124 sets, and the electronic control unit is configured to measure the voltage VD13 between the star neutral points of the first 123 and third 125 sets, and to measure the voltage VD23 between the star neutral points of the third 125 and second 124 sets. There are also impedances Z13, Z23 between these neutral points to facilitate the detection of these respective voltages VD13, VD23.

[0091] In general, the inverter 184 comprises as many independent control arms 1840 as there are phases in the set of stator assemblies.

[0092] More generally, and as can be seen in [Fig.9], when the stator 122 comprises at least three sets, each neutral point of each star of each set is electrically coupled to at least two neutral points of two stars of two other sets of the stator 122, and the electronic control unit 18 is configured to measure the voltage differences between the neutral point and each of the neutral points to which it is coupled.

[0093] When the motor 10 comprises at least three sets, measuring voltage differences between the neutral points of the star connections of the sets is sufficient to determine a difference in behavior between two sets driven in the same way, and to identify which set would be affected by a fault. Indeed, when a set is affected by a fault, voltages will be detected between the neutral point of its star connection and the neutral points of the stars to which its neutral point is electrically coupled, and these voltages will exceed the chosen threshold.

[0094] When the motor 10 comprises only two sets, the voltage difference measurements can be supplemented by other measurements to determine a difference in behavior when the sets are driven in the same way. For example, the electronic control unit can be configured to measure the voltage at each terminal of each phase of the first 123 and the second 124 set, and to compare them to a divergence threshold. When the voltage between the neutral points exceeds its voltage threshold, and the voltage between two phases of the same set exceeds the divergence threshold, the motor 10 can signal a fault in the set corresponding to the diverging phases.

[0095] It is also envisaged to do the same for each phase of each assembly when the motor 10 comprises more than two assemblies, although this is not essential, when the motor 10 comprises at least three assemblies, in order to be able to detect faults at the level of a given assembly.

[0096] The presentation thus provides an architectural solution for an intelligent motor that makes it possible both to improve the power-to-weight ratio of the motor for applications requiring a lightweight, powerful motor with its own power and control electronics, and to guarantee the supply of mechanical torque in the event of a failure of the voltage inverter arm of a star of a stator for an intelligent motor.

[0097] Although the motor 10 is presented as having its control unit in the housing, it is also envisaged to locate the control unit outside the housing, for example, to facilitate the integration of the motor 10 into small spaces.

[0098] The motor 10 has been presented in the context of an aircraft propulsion motor. It is also envisaged to use a motor such as described herein as an electromechanical flight control actuator motor, as an electromechanical landing gear movement actuator motor, as a pump or fan motor - for example for critical applications (cockpit ventilation, hydraulic pump, fuel pump), or for any other application for which operational safety is a key characteristic.

[0099] Furthermore, it is envisaged that such an engine could be used outside the aerospace field. Numerous other applications can be considered, while remaining within the scope of this presentation.

Claims

Demands

1. Intelligent motor (10) comprising: - an electromechanical permanent magnet converter (12); and - an electronic control unit (18); the electromechanical converter (12) comprising: - a permanent magnet rotor (121); and - a stator (122) comprising: - a first assembly (123) comprising at least three phases electrically connected to each other in a star configuration; - a second assembly (124) comprising as many phases as the first assembly, the phases of the second assembly being electrically connected to each other in a star configuration; and - an impedance between the neutral points of the stars of the first and second assemblies; said electronic control unit comprising a control inverter (184), comprising as many independent control arms (1840) as there are phases in the first assembly and as many independent control arms as there are phases in the second assembly;the control inverter being configured to drive each phase of the first set and each phase of the second set by its own control arms; the electronic control unit being configured to measure a voltage difference (VD12) between neutral points of the stars of the first and second sets with respect to a voltage reference common to said sets.

2. Intelligent motor (10) according to any one of the preceding claims, configured to isolate the first and second sets from each other in response to an exceedance of a voltage threshold by the voltage between the neutral points of their stars.

3. Intelligent motor (10) according to claim 2, wherein the voltage threshold is equal to or greater than seven, ten or thirteen volts, and less than or equal to fifty, thirty, twenty-five, twenty, or seventeen volts.

4. Intelligent motor (10) according to claim 2 or 3, configured to measure the voltage at each terminal of each phase of the first and second sets, and to signal a fault in a given set in response to an exceedance of a divergence threshold by a difference between the voltages of two of its phases.

5. Intelligent motor (10) according to any one of the preceding claims, wherein: the stator comprises at least one assembly other than the first and second assemblies, comprising (each) as many phases as the first assembly, electrically connected to each other in a star configuration, the voltage reference being common to the first and second assemblies and to said assembly(ies) other than the first and second assemblies; the inverter further comprises as many independent control arms as there are phases of the (assembly of) assemblies other than the first and second assemblies; the inverter is further configured to drive each phase of the (assembly of) assemblies other than the first and second assemblies by its own control arm;The electronic control unit is further configured to: - measure a voltage difference between the neutral point of the star of the first set and the neutral point of the star of (one of) the set(s) other than the first and second sets; - measure a voltage difference between the neutral point of the star of the second set and the neutral point of the star of (one of) the set(s) other than the first and second sets with respect to the common reference.

6. Intelligent motor (10) according to any one of the preceding claims, wherein said stator (122) comprises a series of teeth arranged in a circumferential direction of the stator, each phase comprising a coil - or a series of several coils - wound(s) around a single tooth of the stator.

7. Intelligent motor (10) according to any one of the preceding claims, wherein the rotor (121) comprises Halbach configuration magnets.

8. Intelligent motor (10) according to any one of the preceding claims, wherein the stator (122) is divided into distinct angular ranges, the number of angular ranges of a stator corresponding to the number of stator sets, the angular range extending over an angle corresponding to the result of dividing 360° by the number of stator sets, or by an integer multiple of the number of stator sets.

9. Intelligent motor (10) according to any one of the preceding claims preceding, in which the electronic control unit (18) further comprises a current regulation module configured to regulate the current in the assemblies independently of each other, and a rotor speed regulation module (121).

10. Intelligent motor (10) according to any one of the preceding claims, further comprising a connection interface linking a high-voltage DC power bus to each of the arms (1840) of the inverter (184) of the electronic control unit (18), the connection interface comprising a capacitive decoupling stage (16) equipped with differential mode capacitors.

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