Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
  • H02K11/30—Structural association with control circuits or drive circuits
  • H02K11/33—Drive circuits, e.g. power electronics
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
  • H02K11/20—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection for measuring, monitoring, testing, protecting or switching
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K9/00—Arrangements for cooling or ventilating
  • H02K9/22—Arrangements for cooling or ventilating by solid heat conducting material embedded in, or arranged in contact with, the stator or rotor, e.g. heat bridges

Definitions

• the present invention relates to the field of mechatronics and more particularly to electric actuators, for example for automotive applications such as the rapid phase shift of the camshaft of internal combustion engines, over the entire operating range (including when the engine is off), to reduce emissions and fuel consumption while ensuring optimum vehicle performance; as well as the actuation of the water pump of the cooling circuit, to improve the fuel consumption of hybrid vehicles and increase the range of electric vehicles.
• Such actuators can be placed near the component to be controlled and connected to the automobile battery which then constitutes the power source, a vehicle computer sending the requested steering and torque level information to an electronic circuit.
• power integrated in the actuator Due to their level of integration on the heat engine, these actuators must be extremely compact, which requires optimizing both the engine part and the electronic circuit. More generally, it is possible to envisage, for such actuators, other applications where the mechatronics assembly must deliver a high torque with a high adjustment dynamic and a high precision.
• patent application DE102018117987 describes another electric motor solution equipped with a basic motor module and a plug-in module which is electrically and mechanically connected to the basic motor module and is designed as an electronic module.
• the electronic module consists of the power electronics, the drive electronics and the control electronics, the electronics module and the base motor module each dissipating heat via a heat path (A, B), the heat paths (A, B) being separated from each other.
• This solution does not make it possible to optimize thermal control.
• Patent application WO2015144156A1 is also known, which proposes an evacuation solution via the metal cover closing the rear of a mechatronic assembly.
• the actuator comprises an electric motor equipped with a stator, mounted and fixed in a first housing element, and an electronic module which is mounted and fixed in a second housing element which is itself connected to a stator winding by means of cables. passing through at least one housing element.
• the housing elements form a single unit heat conducting unit and the housing is designed as a heat sink for the stator and the electronic module.
• the evacuation by the rear cover is not optimal because this part of the actuator is made of plastic material, having poor thermal conductivity, and its outer surface is exposed to the thermal environment which can be relatively high, in particular for applications concerning heat engines.
• the present invention relates in its most general sense to an actuator comprising: a stator assembly (30) formed by a pack of sheets (32) surrounded by coils (31) and at least one connector (35, 39), a magnetized rotor assembly (13), an electronic circuit (20) comprising the electronic power components (28, 29) for supplying said stator coils (31), a flange (1) being at least in metallic part, said stator assembly (30) coming into thermal contact with said flange (1), said stator assembly (30) having a housing of a first bearing (11, 12) for guiding a motor shaft (10), characterized in that the metal part of said flange (1) forms a front surface (2) traversed by said motor shaft (10) intended to be connected to the device to be controlled, the electronic power components (28, 29) of said circuit electronics (20) being in direct thermal contact o u indirect with the inner wall of said flange (1) in order to create thermal bridges between the electronic circuit and the metal part of the flange to
• the stator assembly is in direct or indirect thermal contact with the front surface (2) to create thermal bridges in order to evacuate heat through the front surface on the output side of the motor shaft, said electronic circuit is in contact with said stator assembly to form a block, and that the front surface is configured to receive the block formed by said electronic circuit attached to said stator assembly, the stator assembly is overmolded in a material having a thermal conductivity greater than that of the air, or inserted into a metal casing, said flange comprises a second guide bearing for the motor shaft, said stator assembly ensures the rear closure of said flange, said magnetized rotor assembly comprises a magnet for encoding the position of the rotor capable of interacting magnetically with a magnetic sensor placed on said electronic circuit, the outer surface of said stator assembly exhibits timing elements of said electronic circuit, said coils are electrically connected to the electronic circuit by pressure connectors of the “pressfit” type or alternatively, via metal “leadframes” tracks, the electronic circuit has filtering components of reduced bulk and is positioned in front surface (2)
• the actuator comprises intelligent electronics and at least two independently controllable three-phase windings, two microcontrollers or a dual microcontroller, the intelligent electronics being able to detect an internal fault by diagnosing the electronic and electrical elements, being able to control an exempt three-phase winding. of faults in order to offer at least half of the nominal torque at nominal current and able to inform the system via the communication channel.
• the architecture of the actuator according to the invention has the effect that the electronics and the wound stator are placed in thermal contact with the flange, as close as possible to the customer interface, which promotes and simplifies the thermal exchanges with this last.
• such an architecture makes it possible to simplify the overall structure of the actuator, for example by eliminating the rear cover and the associated ultrasonic welding operation or by any other equivalent solution such as gluing, laser welding, etc.
• FIG. 1 shows a sectional view of a first variant embodiment more specifically intended for an application of an electronic camshaft phase shifter
• FIG. 2 shows a perspective view of an exploded partial section of the overmolded stator assembly according to the first variant embodiment
• FIG. 3 shows two perspective views from above of the stator assembly of the first variant embodiment before and after the engagement of the electronic circuit
• FIG. 4 shows a perspective view in partial section of the first embodiment showing the electronic circuit
• FIG. 5 shows a sectional view of a second variant embodiment
• FIG. 6 shows two perspective views from above of the stator assembly of the second variant embodiment before and after the engagement of the electronic circuit
• FIG. 7 shows a perspective view in partial section of the second embodiment showing the electronic circuit
• FIG. 8 shows a sectional view of a third variant embodiment
• FIG. 9 shows a perspective view from above in partial section and a perspective view from below of the stator assembly of the third variant embodiment and showing the electronic circuit
• FIG. 11 shows a perspective view from above of the fourth embodiment, the flange being detached and seen in three-quarter section,
• FIG. 12 shows a perspective view from above of the fourth variant embodiment without a flange and either without or with the electronic circuit
• FIG. 13a and FIG. 13b illustrate a comparison of the currents of the power bus and their harmonic decomposition in the case of a conventional architecture and of an architecture optimized to limit the oscillations thereof
• FIG. 14 shows a block diagram of the control assembly of a mechatronic assembly according to the invention.
• Said variants relate to an application of the invention of the electric camshaft phase shifter or water pump type, these two applications differ only in the shape of the flange, which allows the actuator to be assembled for the application.
• the invention relates to the development of a novel optimized architecture, in particular from a thermal point of view. Indeed, such an actuator operates in a difficult environment corresponding to the engine compartment of the vehicle. In addition to vibration stresses, the actuator is subjected to high temperatures (> 120 ° C). However, the latter is said to be intelligent because it comprises complex on-board electronics, some of whose components have critical temperatures that must not be exceeded.
• the invention aims to use the receiving interface of the actuator, that is to say the cylinder head of the internal combustion engine or the pump body, in order to dissipate the heat emitted by the actuator.
• FIGS. 1 to 3 represent a first exemplary embodiment, more specifically intended for an application of an electronic camshaft phase shifter.
• the flange (1) forms a stamped solid block with a front face (2) traversed by the motor shaft (10) driving the member coupled to the actuator.
• the flange (1) defines a housing in which are positioned: the electronic circuit (20) an overmolded stator assembly (30).
• the flange (1) has an annular transverse flare (3) complementary to an annular flare (33) of the overmolded stator assembly (30).
• the flange (1) and the overmolded stator assembly (30) are assembled by means of said annular flares (3, 33) and then held by screws inserted in hollow metal parts (4), allowing the actuator to be fixed on a member. complementary, for example an engine cylinder head.
• the transverse flare shape is not limited to annular. All the other shapes of the flares, which make it possible to assemble the flange and the stator assembly, can be used.
• This embodiment also comprises a magnetic rotor assembly (13) comprising a rotor with magnets, a motor shaft (10) and optionally a positioning magnet (17).
• Said motor shaft (10) is linked to a rotor with permanent magnets made for example of sintered magnets. It is constituted in a known manner by a pack of sheets (16) in which pieces of magnets (15) are embedded.
• a rotor with surface magnets can be implemented.
• the motor shaft (10) is guided by a front bearing (11) crimped into the front face (2) of the flange (1) and by a rear bearing (12) integrated in the overmoulded stator assembly (30) .
• the motor shaft (10) being able to present at its front part a positioning magnet (17) interacting magnetically with Hall probes (26) mounted on the electronic circuit (20) to deliver information on the angular position of the rotor.
• front will denote the side of the output of the motor shaft (10), this qualifier applying to all the components.
• the overmolded stator assembly (30) incorporates a yoke formed by a bundle of sheets (32) surrounded by coils (31).
• the electrical connection between the coils and the electronic circuit (20) is made in a known manner by needle-eye connectors (27) (commonly described as of the “pressfit” type).
• the overmolding has, on its front end face, protuberances forming positioning pins (34) of the electronic circuit (20).
• the overmolded stator assembly (30) also incorporates one or more overmolded connectors (35, 39).
• One of the connectors (35) receives the DC power supply current.
• the other connector (39) is intended for the input and output of low power control signals: input of the setpoint, preferably image of the torque and direction of rotation requested at the input, output of signals informing about the direction and the speed of rotation.
• the connectors (35, 39) comprise metal tracks terminated by connectors (40, 41) of the pressfit type intended to ensure the arrival of the power supply and the control signals to the electronic card (20).
• the overmolded stator assembly (30) thus forms a monolithic block, of cylindrical shape extended by the connectors (35, 39), defining a central cavity for the insertion of the rotor.
• the disc-shaped electronic circuit (20) can be pushed against the front surface to allow engagement of the connectors (27) and locating pins (34) in the corresponding holes of the printed electronic circuit (20).
• a thermal paste or glue is deposited between the rear surface of the electronic circuit (20) and the front face of the stator assembly (30) overmolded to improve thermal conductivity between the electronic circuit (20) and the mass of the overmolded stator assembly (30).
• This assembly is then slipped into the flange (1) before sealing by the peripheral links.
• This seal (38) may be of the “shape seal” type, that is to say a shaped seal, in order to ensure the seal between the overmolded stator assembly (30) and the flange (1), or an O-ring.
• a shaped seal In the case of a shaped seal (38), the seal is effected on the flat face of the flange (1) and the groove housing the seal is circular.
• a shaped seal is suitable for this type of plane contact, and in addition, it has gadroons allowing it to be held in the groove provided for this purpose.
• the electronic circuit (20) is thus positioned within the inner surface of the front face of the flange (1).
• a thermal paste or glue ensures thermal conduction between the power components, either the power electronic components (29) of the power bus filter, or the power electronic components (28) being MOS type power switches. , and the inner surface of the flange (1).
• a nominal distance is maintained between the bottom of the flange (1) and the surface of the electronic components of said electronic circuit (20), the entire electronic circuit (20) can then be in thermal contact with the flange (1) by the intermediate of thermal paste, a thermal adhesive, or possibly a foam with high thermal conductivity.
• the positioning magnet (17) magnetically interacts with Hall probes (26) mounted on the electronic circuit to provide information on the angular position of the rotor.
• FIGS. 4 to 7 represent a second exemplary embodiment for an application of an electronic camshaft phase shifter.
• This differs from the previous one in that the coils (31) are no longer directly connected to the electronic circuit (20) by the “pressfit” connectors (27), but via metal tracks (21) or “leadframe”.
• metal tracks (21) or “leadframe” In English in order to eliminate the routing of the coils on said electronic circuit (20) which makes it possible to increase the supply current of the coils.
• a metallic track (21) per electrical phase is used and makes it possible to ensure the distribution of the current to the coils associated with this phase.
• said metal tracks (21) are assembled in a support part (22) allowing precise positioning and maintenance of the metal tracks (21) on the coiled sheet pack (32), before the overmolding operation, then integrating the overmolded stator assembly (30).
• the invention includes the use of insulation displacement connectors (not shown) to ensure the electrical connection of the metal tracks (21) to the coils (31) during the operation of positioning the support part (22) on the pack of sheets ( 32) wound.
• the connectors (24) terminate the metal tracks (21) at their second end and make it possible to ensure electrical contact with the electronic circuit (20).
• they are of the “pressfit” type and the number of connectors per track is adjusted as a function of the maximum supply current of the electrical phases.
• this example is not limiting and any type of connection of the tracks to the electronic circuit that a person skilled in the art would consider is included in the invention.
• This embodiment also differs from the first in that said metal tracks extend axially above the coils (31), reducing the space allocated to the electronic circuit (20) on the outer periphery.
• said electronic circuit extends over its inner periphery and therefore requires placing the positioning magnet (17) axially facing the electronic circuit (20).
• FIGS. 8 and 9 represent a third exemplary embodiment for an application of an electronic camshaft phase shifter.
• This embodiment differs from the previous two in that the electronic circuit (20) is not located inside the transverse annular flare (3), but attached to the rear part of the stator assembly (30). overmolded.
• This embodiment is preferred in the case where the electronic power components (29) associated with the electronic filter of the power supply are particularly bulky and cannot be advantageously installed inside the metal flange (1).
• the installation of the electronic circuit (20) on the rear part of the overmolded stator assembly makes it possible to use the space located around the connectors (35, 39) for disposing said electronic power components (29) without increasing the overall dimensions of the electric actuator.
• a leadframe type connection between the coils (31) and the electronic circuit (20) is used so as to limit the dimensions of said electronic circuit.
• thermal bridges connect said electronic circuit (20) to the flange (1), these thermal bridges are produced using a metal part (37) showing axial growths (36).
• Said axial protuberances (36) are advantageously housed in clearances (320) of the pack of sheets (32) to provide a large contact surface with the pack of sheets (32) in order to ensure good evacuation of the heat produced by the losses. in the coils (31) and the sheet metal pack (32), but also so as not to impact on the radial size of the electric actuator.
• a nominal clearance between the electronic circuit (20) and the metal part (37) makes it possible to ensure good thermal contact by adding a paste, a foam, or a thermal adhesive filling said clearance.
• thermal contact between the metal part (37) and the flange (1) is provided on both sides by the axial protuberances (36) and the transverse annular flare (3). Finally, a nominal axial clearance between the overmolded stator assembly (30) and the flange (1) is ensured and can be filled with a thermal paste or a thermal foam in order to promote the evacuation of the calories.
• the annular shape of transverse flare has no limiting effect, but only illustrative. All other shapes of flares are possible.
• FIGS. 10 to 12 represent a fourth exemplary embodiment for a water pump application.
• This embodiment differs from the first embodiment in that the overmolded stator with its electric coils is inserted into a metal casing (5) in order to constitute the stator assembly. It also differs in that the transverse flaring (33) is not produced in the overmolding of the stator, but in the metal casing (5) and in that it does not have a magnet (17) to determine the angular position of the motor shaft (10), this not being particularly desired in the context of a pump.
• the flange (1) has in its front part a chamber (18), thus forming part of the chamber of the pump body in which the fluid is pumped, this chamber (18) being connected to a duct (25) conveying the pumped fluid.
• the rear guide (12) of the rotor assembly (13) is a sliding bearing fixed in a flare of the metal casing (5). It can be noted that in the embodiment presented, the front guide (11) is not present, this second guide being produced by the pump to which the actuator is assembled, nevertheless the motor shaft (10) of the rotor is partially guided by an axial annular protuberance (8) of the overmolding of the stator.
• Said axial annular protuberance (8) opens onto the chamber (18) of the flange (1), and has a diameter slightly greater than the motor shaft (10) so as to let the fluid to be pumped into an internal cavity of the 'stator assembly (30), the fluid then being able to be as close as possible to the packets of sheets (16, 32) of the rotor and of the stator.
• the actuator is assembled by inserting the rotor assembly into the metal casing (5) at the level of the first bearing (12), then the overmolded stator is driven into the metal casing (5) by guiding partially the motor shaft (10) of the rotor.
• the electronic card is then assembled on the overmolding of the stator and the flange (1) inserted and held to the stator assembly (30) by fixing screws.
• this embodiment differs in that it has a single overmolded connector (35) making it possible both to transmit the power supply and the control signals.
• This embodiment is not, however, limiting of the invention in the context of a pump because the possibility of optimizing the cooling by letting the pumped fluid flow within the magnetic actuator brings additional constraints, such as the management of the tightness which must be done through the addition of multiple gaskets (58, 68) in order to avoid any contact of the fluid with the electronic card, or even by overmolding (6) of the inner surface of the stator sheets and a shrink wrap (14) of the rotor so as to prevent corrosion of the sheets, the latter elements increasing the magnetic air gap reducing the performance of the actuator.
• this construction does not overcome the evacuation of heat by placing the stator assembly (30) and the electronic card (20) in direct thermal contact with the flange (1), which remains the dissipation means. privileged, this flange (1) allowing better heat exchanges with the circulating fluid. In fact, in the configuration presented, the fluid entering the internal cavity of the stator is not constrained to a flow and the drainage of the calories is then done more by conduction.
• a significant gain in axial size results from the integration of the electronics directly into the flange (1).
• This integration is only made possible by reducing the dimensions of the components of the power supply filter, namely capacitors and inductors.
• two strategies can be implemented. The first results directly from the technological evolution of power electronics, which makes it possible to obtain much smaller dimensions at iso-power, typically a volume reduction by a factor of 2 or 3.
• An alternative that we are considering is to adapt the motor control, preferably in block switching (BCC - Block Commutation Control) but potentially in vector control (FOC - Field Oriented Control), to limit the current oscillations that the power supply filter will have to absorb.
• Figure 13a illustrates a comparison of the current oscillations of the power supply at the head of the inverter, said inverter feeding the BLDC motor through block switching (BCC), between a conventional 3-phase configuration ( 61), a non-optimized configuration involving more than 3 phases (62) and an optimized configuration involving more than 3 phases (63).
• Figure 13b illustrates a comparison of the harmonic decomposition of the power supply current at the level of the inverter head, the latter supplying the BLDC motor thanks to a so-called block switching (BCC), between a conventional configuration at 3 phases (70) and an optimized configuration involving more than 3 phases (80) and showing the reduction of 45% of the harmonics associated with the fundamental chopping frequency of the inverter (71) as well as the reduction of the spectral content of more low frequency (72).
• BCC block switching
• This alternative embodiment exploits the space located on the opposite side of the metal flange, the radial size of which is less restricted, it is then possible to advantageously arrange the filtering components around the stator overmolding in order to limit the axial size while controlling the pressure. radial bulk.
• FIG. 14 represents a block diagram of the control assembly of a mechatronic assembly according to the invention.
• the system described by the invention proposes to use an intelligent electronic architecture in order to mitigate the degradation of one or more electronic or electrical elements constituting said system.
• the control electronics can detect it by diagnosing the electronic elements, namely said at least one microcontroller (52), said power switches (28), said module (51) and the electrical elements. , or said motor architecture (100), making up the system, then check at least one of the fault-free assemblies including one of the two three-phase windings in order to offer at least half of the nominal torque at nominal current in said three-phase winding and finally inform the ECU by the communication channel (112) using a defined communication protocol.
• the fault-free assembly including one of the two three-phase windings can transiently offer an emergency mode with more than half of the nominal torque (Tsecours> 50% Tnominai) by increasing the current in the power switches (28) and therefore the three-phase winding.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Motor Or Generator Frames (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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Family Cites Families (8)

• 2020
  • 2020-04-03 FR FR2003381A patent/FR3109034B1/fr active Active
• 2021
  • 2021-03-25 EP EP21714157.1A patent/EP4128492A1/de active Pending
  • 2021-03-25 WO PCT/EP2021/057687 patent/WO2021197995A1/fr active Application Filing

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