Module for inductive charging of an electric vehicle and assembly comprising such a module

Abstract

Module (102) for inductive charging of an electric vehicle, comprising a body carrying a resonant inductive cell (10, 20), comprising at least one inductance (31) formed by an electrical conductor (33) wound on a core (34), the resonant inductive cell (10, 20) having a resonant frequency of less than 5kHz, characterized in that the module (102) carries at least one piezoelectric transducer (50) arranged inside the pattern defined by the electrical conductor (33) wound on the core (34) Abstract figure: Fig.3

Description

Title of the invention: Module for inductive charging of an electric vehicle and assembly comprising such a module

[0001] The present invention relates to a module for inductive charging of an electric vehicle, and an assembly comprising such a module.

[0002] Such a module forms, for example, a charging mat intended to be placed in or on the ground and / or to be electrically connected to a charging terminal itself electrically connected by wire to an electrical network. Alternatively, such a module is intended to be fixed to the vehicle, for example being fixed to the chassis of the vehicle.

[0003] The vehicle has, for example, a battery intended to power an electric machine for propelling the vehicle, this battery having a nominal voltage whose value may be 48V, or greater than 60V, being for example greater than 200V or 300V, being in particular 400V or 800V.

[0004] It is known to charge this battery inductively, also called "contactless", when the vehicle is stationary by means of an inductor arranged on or in the ground which exchanges electrical energy without contact by inductive coupling with an inductor in the vehicle's on-board network. The presence of these two inductors, designed to transmit a power which can be between 3 kW and 50 kW, can cause unpleasant noise for people present in the vicinity of the vehicle.

[0005] There is a need to remedy this drawback.

[0006] The invention aims to meet this need and achieves this, according to one of its aspects, using a module for the inductive charging of an electric vehicle, comprising a body carrying a resonant inductive cell, comprising at least one inductance formed by an electrical conductor wound on a core, the resonant inductive cell having a resonant frequency of less than 5kHz,

[0007] characterized in that the module carries at least one piezoelectric transducer arranged inside the pattern defined by the electrical conductor wound on the core.

[0008] The piezoelectric transducer can be controlled to generate a mechanical wave compensating in whole or in part the mechanical wave generated by magnetostriction in the body due to the flow of current in the electrical conductor. Thus, the consequences in terms of vibration and noise in the body of the module due to the flow of current in this body during the exchange of electrical energy without contact by inductive coupling can be reduced or even cancelled. These vibrations can include vibrations of the electrical conductor wound on the core.

[0009] The phase and / or amplitude of the mechanical wave generated by magnetostriction in the body due to the flow of current in the electrical conductor may have been determined previously, for example during a design phase, and the piezoelectric transducer may be controlled to generate a mechanical wave out of phase, in particular in phase opposition, with that caused by said flow of current.

[0010] According to an exemplary implementation, the module forms a mat for inductive charging of the electric vehicle, the mat being intended to be placed in or on the ground and / or to be electrically connected to a charging terminal itself electrically connected by wire to an electrical network. Such a module can, when connected to a charging terminal, make it possible to minimize the presence in the mat of the components necessary for charging the vehicle inductively, such as one or more voltage converters and / or capacitors and / or filters. It is thus possible to reuse as much as possible for inductive charging these electronic components which are already provided in the charging terminal for wired charging of the vehicle. It is thus possible to facilitate inductive charging by making it possible as soon as a wired charging terminal is present and available.

[0011] The piezoelectric transducer may be powered by a sinusoidal voltage whose frequency is equal to twice the frequency of the electrical energy exchanged without contact by inductive coupling, that is to say the resonant frequency of the resonant inductive cell. Alternatively, the supply voltage of the piezoelectric transducer is not sinusoidal but has a fundamental equal to twice the frequency of the electrical energy exchanged without contact by inductive coupling.

[0012] The electrical conductor wound on the core is, for example, a wire. Alternatively, it may be electrical tracks or a bar also called “flat copper”. It can define any kind of pattern, for example a circle, a rectangle, a square, an ellipse, an oval, or other.

[0013] The carpet can be placed on the floor, being rigidly fixed or not on the floor.

[0014] Alternatively, the mat may be laid in the ground, being completely buried or only partially buried.

[0015] The carpet may be rigid or flexible. According to the invention, “rigid” means that the carpet cannot be deformed without this deformation being irremediable, whereas “flexible” means that the carpet can be deformed and have the capacity to return to its initial shape when the stress that generated the deformation ceases. Such a carpet is, for example, produced according to the teaching of the application filed in France on 09 / 11 / 2023 under number 23 09545 by the Applicant.

[0016] According to a second example of implementation, the module is fixed to the vehicle, for example to the chassis of the vehicle. The module has for example the articulated structure described in the application filed in France on 20 / 11 / 2023 under number 23 12760 by the Applicant.

[0017] According to a third example of implementation, two modules each being as above are provided, one of the modules forming a mat and exchanging without contact by inductive coupling electrical energy with the other of the modules which is fixed to the vehicle. Each of these modules then comprises at least one piezoelectric transducer.

[0018] The resonant inductive cell may also comprise a capacitor, forming with the inductor a resonant LC cell. The capacitor and the inductor are for example connected in series.

[0019] Alternatively, as will be seen later, the resonant inductive cell is devoid of a capacitor, being in particular formed exclusively by the inductance. The fact of not using a capacitor for the resonant inductive cell can make it possible to avoid the appearance of noise generated by the circulation of the current in this capacitor.

[0020] In all of the above, the module may comprise a single piezoelectric transducer. Such a solution is suitable, for example, when the maximum distance between the piezoelectric transducer and the wound electrical conductor of the inductance is less than half the wavelength of the mechanical wave generated by the piezoelectric transducer. As already mentioned above, the piezoelectric transducer may be controlled to generate a mechanical wave compensating in whole or in part the mechanical wave generated by magnetostriction in the body due to the flow of current in the electrical conductor. Considering that the average propagation speed of a wave in a solid material is of the order of 4000 m / s and considering that this wave has a frequency equal to twice the frequency of the current flowing in the electrical conductor, a wavelength value of 67 cm is obtained in the case of a current frequency of 3 kHz.

[0021] Thus, for example, in the case where the wound electrical conductor defines a circular pattern, a single piezoelectric transducer can be used placed at the center of the circle thus defined when the radius of this circle is less than half the wavelength, therefore 33.5 cm with the numerical values above.

[0022] Alternatively, in all of the above, the module may comprise a plurality of piezoelectric transducers, in particular distributed homogeneously within the pattern defined by the wound electrical conductor of the inductor. Such a solution is for example suitable when the maximum distance between the piezoelectric transducer and the wound electrical conductor of the inductor is greater than half the wavelength of the mechanical wave generated by the piezoelectric transducer. For example, in the case where the wound electrical conductor defines a circular pattern, several piezoelectric transducers may be used distributed in the circle thus defined when the radius of this circle is greater than half the wavelength, therefore 33.5 cm with the previous numerical values. Two, three, four or more piezoelectric transducers are for example provided. When several piezoelectric transducers are provided, and unlike the case where a single piezoelectric transducer is provided, each transducer can be controlled to generate a mechanical wave:

[0023] - compensating in whole or in part the mechanical wave generated by magnetostriction in the body due to the flow of current in the electrical conductor, as perceived at the location where this piezoelectric transducer is arranged, and

[0024] - compensating in whole or in part the mechanical wave generated by each other piezoelectric transducer as perceived at the location where this piezoelectric transducer is arranged.

[0025] Alternatively, when several piezoelectric transducers are provided, they can all receive the same electrical command, and not a dedicated electrical command which is a function of their position relative to the other transducers.

[0026] When several piezoelectric transducers are provided, they can define a regular pattern so that one transducer is arranged in the center of the pattern and the other transducers are arranged so as to maintain a constant distance between them. In the case where four transducers are provided, the pattern is for example an equilateral triangle, each vertex of which corresponds to the position of a transducer and the fourth transducer is arranged at the center of gravity of this equilateral triangle.

[0027] The inductance comprises for example a core, in particular made of ferrite, and the electrical conductor is for example wound around this core. The ferrite core is for example confined between two parts of the body, these parts being for example stacked. The ferrite core is then fixed relative to each part of the body.

[0028] Alternatively, the core of the inductor is made in one piece with all or part of the body. According to this variant, this part of the body can be made of a magnetically charged material. This is for example magnetically charged plastic. The choice of the magnetic charge, its concentration and / or its distribution can make it possible to emulate for the core the behavior of a ferrite without ferrite being used, while giving more flexibility as to the choice of the form factor for the core. The production of this part of the body and the core can for example be done in a single step, for example by overmolding on the wound electrical conductor.

[0029] The body is for example overmolded onto the piezoelectric transducer. Other examples of fixing the piezoelectric transducer to the body are possible.

[0030] The body may be a single piece or be formed by several distinct parts. When several distinct parts are used, they may be referred to as sub-bodies. One of the sub-bodies carries for example the inductance and the piezoelectric transducer(s) while another sub-body can carry the capacitor of the resonant inductive cell when such a capacitor is present and other components of the module for example.

[0031] The attachment between the sub-bodies is for example removable, being for example carried out using screws. It is then possible to replace one sub-body independently of the other(s). In particular, the ecological cost of maintaining the module or the cost of adapting it to a specific power level to be exchanged is then reduced. Still according to this variant in which the body is not a single piece, one of the sub-bodies does not carry components where appropriate but provides functions of reinforcing the module or gripping the module, for example.

[0032] According to one or other of the aforementioned implementation examples, each sub-body can be produced by molding material. The components carried by each sub-body are for example encapsulated, in other words “entirely surrounded”, in the material of the sub-body, which can make it possible to confine the acoustic noise in particular and to ensure watertightness. As already mentioned, these two sub-bodies can be screwed together.

[0033] In all of the above, the body, and where appropriate each sub-body, may be made of a polymer plastic material such as PVC, plexiglass (PMMA) or even PBT or PPS. The material chosen is advantageously electrically non-conductive and magnetically non-conductive.

[0034] In all of the above, each piezoelectric transducer is advantageously made of quartz. Each transducer can be powered by a voltage generated from a voltage of the vehicle's on-board network. The supply voltage of the piezoelectric transducers is for example an alternating voltage whose amplitude is for example equal to 12V.

[0035] The invention also relates, according to another of its aspects, to an assembly comprising:

[0036] - an inverter / rectifier comprising at least two switching arms, each switching arm comprising two electronic switches arranged on either side of a midpoint, and

[0037] - the above module, the resonant inductive cell being mounted between two points inverter / rectifier environments.

[0038] As already mentioned, the inverter can be controlled so as to allow the circulation in the resonant inductive cell of an alternating current whose frequency is less than 5 kHz, for example less than 3 kHz, or even less than 2 kHz or 1 kHz, in particular still substantially equal to 400 Hz or 50 Hz.

[0039] The invention can then allow low frequency inductive charging, for example according to the teaching of the international application with filing number PCT / EP2023 / 059845 filed on 04 / 14 / 2023 by Valeo Equipements Electriques Moteur or of the application with filing number 2209978 filed on 09 / 30 / 2022 in France by Valeo Systèmes de Contrôle Moteur.

[0040] The switching arms of the inverter / rectifier can be controlled so that the voltage across the AC input of this inverter / rectifier emulates the presence of a capacitor connected in series with the resonant inductive cell. This avoids the generation of noise associated with the presence of a capacitor in the resonant inductive cell.

[0041] In all of the above, the assembly may comprise an electrical energy storage unit connected to the terminals of the DC input of the inverter / rectifier, the inverter / rectifier being controlled so as to carry out an impedance adaptation of the impedance on the AC input of this inverter / rectifier, independently of the impedance of the electrical energy storage unit.

[0042] One of the two switching arms of the inverter / rectifier can be controlled to switch at the frequency of the electrical energy exchanged without contact by inductive coupling and with a duty cycle of 50%, and the other of the two arms of the inverter / rectifier can be controlled to switch at a frequency higher than that of said electrical energy and with a duty cycle modulated according to the alternating current flowing in the resonant inductive cell and the voltage on the alternating input of this inverter / rectifier. The impedance on the alternating input of the inverter / rectifier is represented by the ratio V / I where V is the voltage across the resonant inductive cell and I the intensity of the current flowing through it.Impedance matching thus makes it possible to impose on the alternating input of the inverter / rectifier an impedance independent of that of the electrical energy storage unit, which promotes contactless exchange by inductive coupling of low-frequency electrical energy.

[0043] The control of the piezoelectric transducer(s) may be carried out by a unit separate from that(those) controlling the inverter / rectifier.

[0044] The assembly comprises for example two modules as described above, one of the modules containing a primary resonant inductive cell belonging to a primary sub-circuit capable of being connected to a voltage network, and the other of the modules containing a secondary resonant inductive cell belonging to a secondary sub-circuit containing the electrical energy storage unit, the primary resonant inductive cell and the secondary resonant inductive cell having the same resonant frequency of less than 5 kHz and being configured to exchange electrical energy without contact by inductive coupling to charge the electrical energy storage unit from the electrical network.

[0045] The invention also relates, according to another of its aspects, to a method for reducing vibrations in a module for the inductive charging of an electric vehicle, comprising a body carrying a resonant inductive cell, comprising at least one inductance formed by an electrical conductor wound on a core, the resonant inductive cell having a resonant frequency of less than 5kHz, method in which:

[0046] - the phase and / or amplitude of the mechanical wave generated by magneto is measured constriction in the body due to the flow of current in the electrical conductor, and

[0047] - we position inside the pattern defined by the electrical conductor wound on the core at least one piezoelectric transducer and this piezoelectric transducer is controlled, this positioning and / or this control being determined to generate a mechanical wave compensating in whole or in part said mechanical wave generated by magnetostriction in the body.

[0048] The invention may be better understood by reading the following description of non-limiting examples of its implementation and by examining the attached drawing in which:

[0049] [Fig.l] schematically represents an electrical power supply circuit in which one or more modules according to the invention can be used,

[0050] [Fig.2] represents a module according to an exemplary implementation of the invention,

[0051] [Fig.3] schematically represents the installation of a single piezoelectric transducer in the module of [Fig.2], and

[0052] [Fig.4] schematically represents the installation of several piezoelectric transducers in the module of [Fig.2].

[0053] [Fig.l] shows a circuit 1 for supplying electricity to an electrical energy storage unit 2. This electrical energy storage unit 2 is, for example, a vehicle battery, which may have a nominal voltage of 48V, 60V, 300V, 400V, 800V or more. This battery is used to supply power to an electric or hybrid vehicle propulsion system.

[0054] This electrical power supply circuit 1 comprises:

[0055] - a control unit 3,

[0056] - a primary sub-circuit 4, capable of being connected to a voltage network 5, and

[0057] - a secondary sub-circuit 6, comprising the electrical energy storage unit 2.

[0058] The electrical power supply circuit 1 implements a contactless exchange of electrical energy by inductive coupling between the primary sub-circuit 4 and the secondary sub-circuit 6, for charging the electrical energy storage unit 2.

[0059] The control unit 3 is for example a microcontroller or any digital processing unit.

[0060] In the example considered, the primary sub-circuit 4 comprises:

[0061] - a connector 9 capable of being connected to the electrical network,

[0062] - an inverter / rectifier 21 comprising here two switching arms 7, mounted in parallel and whose operation will be described below, and

[0063] - a primary resonant inductive cell10 whose operation will be described below- After.

[0064] The electrical network 5 is here represented in the form of a direct voltage network but it can alternatively be an alternating voltage network providing for example a nominal effective voltage of 230V with a frequency of 50 Hz or 60 Hz, as understood from [Fig.2]. Such an alternating voltage electrical network can be single-phase or three-phase. Other voltages are possible, for example a single-phase voltage with an effective value of 120V and a frequency of 60Hz, a two-phase voltage with an effective value of 208V and a frequency of 60 Hz or a three-phase voltage of 240V and a frequency of 60 Hz, this list not being exhaustive. In the case where the network supplies an alternating voltage, another inverter / rectifier 35 not shown in [Fig.l] but visible in [Fig.2] is provided between the network and the inverter / rectifier 21, this other inverter / rectifier 35 providing, for example, a power factor correction function.

[0065] As can be seen in [Fig.l], a capacitor 15 can be arranged in parallel with the two switching arms 7. The latter has, for example, a capacitance between IpF and ImF, for example 1OpF.

[0066] Each arm 7 of the primary sub-circuit 4 here comprises two controllable electronic switches 12, such as MOS, IGBT or bipolar transistors, or thyristors, arranged on either side of a midpoint 8. The two switches 12 of the same switching arm 7 are here controlled using the same duty cycle, one in opposition to the other with a dead time by the control unit 3.

[0067] The first arm 7 thus comprises two controllable electronic switches 12 and a first midpoint 8 to which a terminal of the primary inductive cell 10 is connected and these two controllable electronic switches 12 are controlled according to a duty cycle ab

[0068] The second arm 7 thus comprises two controllable electronic switches 12 and a second midpoint 8 to which the other terminal of the primary resonant inductive cell 10 is connected and these two controllable electronic switches 12 are controlled according to a duty cycle a2.

[0069] In the example considered, no physical component is interposed between the two midpoints 8 of the inverter / rectifier 21 and the primary resonant inductive cell 10.

[0070] As will be seen in [Fig.2], the primary resonant inductive cell 10 can be formed by the series association of: an inductance 31 allowing the generation of magnetic energy, and a capacitor 32, to form a resonant cell. The inductance has for example a value between 100pH and 100mH and the capacitor has a capacity between 10 nF and 1 mF. The inductance is for example produced by winding a copper wire, other than Litz wire.

[0071] In the variant shown in [Fig.l], the primary resonant inductive cell 10 is formed by an inductance only. No physical capacitor is present, the presence in series of this capacitor with the inductance of the primary resonant inductive cell 10 being emulated by the control of the switching arms 7 by the primary control unit 3 using the duty cycles ai and a2. Here again, the inductance is for example produced by winding a copper wire

[0072] An example of secondary sub-circuit 6 will now be described with reference to [Fig.l]. This secondary sub-circuit 6 comprises a secondary inductive cell 20 for the contactless exchange of energy with the primary resonant inductive cell 10, and an inverter / rectifier 23, capable of carrying out an adaptation of the equivalent impedance on its alternating input (therefore on the side of the secondary inductive cell 20), so as to vary this impedance independently of the impedance of the electrical energy storage unit 2.

[0073] The inverter / rectifier 23 comprises in the example described two switching arms 24 arranged in parallel, each arm comprising two controllable electronic switches 12 arranged on either side of a midpoint 25.

[0074] The two switches 12 of the same switching arm 24 are here controlled using the same duty cycle, one in opposition to the other with a dead time by the control unit 3.

[0075] The first arm 24 thus comprises two controllable electronic switches 12 and a first midpoint 25 to which a terminal of the secondary inductive cell 20 is connected and these two controllable electronic switches 12 are controlled according to a duty cycle a3.

[0076] The second arm 24 thus comprises two controllable electronic switches 12 and a second midpoint 25 to which the other terminal of the secondary resonant inductive cell 20 is connected and these two controllable electronic switches 12 are controlled according to a duty cycle a4.

[0077] The secondary resonant inductive cell 20 is here formed by an inductance making it possible to recover the magnetic energy from the primary inductive cell 10. In a variant, a capacitor is also present, so that the secondary resonant inductive cell forms a resonant LC cell. In the example considered, the inductance has a value between 1 mH and 100 mH and the capacitor has a capacitance between 100 pF and 100 mF. The inductance is by example made by winding a copper wire, other than Litz wire.

[0078] Furthermore, the control unit 3 acts in the example described on the control of the inverter / rectifier 23 so as to vary the equivalent impedance RRef at the terminals of the alternating input, defined between the two midpoints 25 of the switching arms 24, independently of the impedance on the continuous output of this inverter / rectifier 23.

[0079] The equivalent impedance RRef is represented by the ratio V / I where V is the voltage between the two midpoints 25, and I the intensity of the current flowing in the secondary resonant inductive cell 20.

[0080] RRef has for example a value between 0.1 'Q and 20'Q, in particular between 5 'Q and 15 'Q. For a given charging configuration, this configuration being in particular determined by at least one of: the position of the secondary sub-circuit 6 relative to the primary sub-circuit 4 and / or the power level to be transmitted and / or the voltage at the terminals of the electrical energy storage unit 2, RRef can have a fixed value and this value is for example in the aforementioned range. From one charging configuration to another, for example in the case of a greater distance between the primary sub-circuit 4 and the secondary sub-circuit 6 and / or to take into account the aging of the system, the value of RRef can be modified, remaining in particular in the aforementioned range.

[0081] The inverter / rectifier 23 of [Fig.l] is for example controlled as follows by the control unit 3, to carry out the impedance adaptation on the alternating input of the inverter / rectifier 23:

[0082] - one of the two switching arms 24 switches at the frequency of the energy electrical exchanged without contact by inductive coupling and with a duty cycle a3 of 50%, and

[0083] - the other of the two switching arms 24 switches at a frequency higher than that of the electrical energy exchanged without contact, for example at least 5 times or 10 times this frequency of the electrical energy exchanged without contact, and with a duty cycle a4 modulated according to the alternating current flowing in the secondary resonant inductive cell 20 and according to the voltage across the alternating input of the inverter / rectifier 23. One of the controllable switches 12 of the switching arm 24 which switches at a frequency higher than that of the electrical energy exchanged without contact is for example controlled according to the duty cycle a4 while the other controllable switch of this arm 24 is controlled according to the duty cycle 1- a 4, and a4 is for example determined according to the equation below:

[0084] œ4 =(Rref xlll) / Vbatt

[0085] where Vbatt denotes the voltage across the terminals of the electrical energy storage unit 2.

[0086] We will now describe with reference to [Fig.2] an example of a module integrating one of the primary 10 and secondary 20 resonant inductive cells.

[0087] The primary resonant inductive cell 10 is for example integrated into a module 102 forming a charging mat as shown in [Fig.2]. The module 102 comprises a body carrying a part of the primary sub-circuit 4. It can be seen in the example described that this part of the circuit comprises the inductor 31 and the capacitor 32 which are connected in series and form the primary resonant inductive cell 10. The inductor is here formed by a core 34, in particular made of ferrite or magnetically charged plastic, and an electrical winding 33, for example an electrical wire wound on the core or electrically conductive tracks. Other ways of producing the inductor are covered by the invention. The winding 33 defines a pattern which can have any shape, for example a circular or square or rectangular or oval shape.

[0088] In the example considered, the body of the module 102 is not a single piece. It comprises, as shown in [Fig. 2], a first sub-body carrying the inductor 31 and a second sub-body carrying the capacitor 32. In the example considered, the second sub-body also carries, in a non-limiting manner:

[0089] - the inverter / rectifier 21,

[0090] - the other inverter / rectifier 35, interposed between the electrical network 5 when it carries an alternating voltage and the direct output of the inverter / rectifier 21,

[0091] - an element 37 of the control unit 3, this element 37 controlling the switches inverter / rectifier electronics 21,

[0092] - a power supply 41 for this element 37 of the control unit 3,

[0093] - an EMC 40 filter, allowing the common mode current and the current of differential mode upstream of the alternating output of the inverter / rectifier 35, and

[0094] - where appropriate, a module 38 for wireless communication interface with the vehicle and a connection 44, for example wired, allowing the exchange of data between this wireless communication interface module 38 and the aforementioned element 37 of the control unit 3.

[0095] The power supply 41 is in the examples considered connected to the element 37 of the control unit 3 by a connection 43 being an electric wire, a rigid bus bar or a printed circuit board track, for example. This power supply is here a battery whose nominal voltage is 12V and which is charged from a charging terminal to which the module 102 is connected via a power connection 42.

[0096] The control of the inverter / rectifier 21 by the element 7 of the control unit 3 can be carried out by a connection 45, being for example an electric wire, a rigid bus bar or a printed circuit board track, for example. It is also possible to use to make the connection 45 a solution of the Bal Spring® type marketed by the Bal Seal Engineering™ company.

[0097] The junction of the rest of the electrical circuit carried by the body with the primary resonant cell 10 is carried out for example via two respective wires 46 and 47 or via two rigid bus bars, for example.

[0098] These first and second sub-bodies are here distinct and fixed to each other, by a removable or non-removable fixing. The first sub-body is for example made of a polymer plastic material such as PVC, plexiglass (PMMA) or even PBT or PPS. The second sub-body is in the example considered made of one of these materials, for example the same as that of the first sub-body. When the core 34 is made of magnetically charged plastic, the core 33 and all or part of the first sub-body can be made in a single piece, for example by overmolding on the electrical winding 33.

[0099] We will now explain with reference to Figures 3 and 4 how the invention makes it possible to reduce the noise generated by the inductances of the primary resonant inductive cell 10 and of the secondary resonant inductive cell 20.

[0100] The module 102 of [Fig.2] carries at least one piezoelectric transducer 50 arranged inside the pattern defined by the electrical winding 34, this piezoelectric transducer 50 being controlled to generate a mechanical wave in phase opposition with the current flowing in the primary resonant inductive cell 10.

[0101] A single piezoelectric transducer 50 is used in the case of [Fig. 3]. This piezoelectric transducer is powered by a variable voltage, for example sinusoidal or more generally alternating with a fundamental which can for example be equal to 6 kHz. This voltage can be obtained from a voltage of the vehicle's on-board network. The piezoelectric transducer 50 is here integrated into the body of the module 102 by overmolding the body onto this piezoelectric transducer. Other embodiments are however possible.

[0102] In [Fig. 3], the electrical winding 33 defines a circular pattern and the piezoelectric transducer 50 is arranged in the center of the circle thus defined. In this example, the radius r of the circle defined by the winding 33 is less than half the wavelength of the mechanical wave generated by the piezoelectric transducer 50 at the frequency considered, namely 33.5 cm here.

[0103] In [Fig. 4], the electrical winding 34 always defines a circular pattern whose radius is greater than half the wavelength of the mechanical wave generated by the piezoelectric transducer 50 for the same frequency considered. Four transducers 50 PO to P4 are then used and distributed homogeneously within the pattern defined by the electrical winding 33. It can be seen in the example considered that the transducers PI to P3 are positioned to define the vertices of an equilateral triangle of side D, while the transducer PO is positioned at the center of gravity of this triangle, being distant from the other transducers by a distance d.

[0104] Each of these transducers 50 is controlled so as to be able to compensate in whole or in part the mechanical wave generated by magnetostriction in the body due to the circulation of the current in the electrical conductor 33, as it is perceived at the location where this piezoelectric transducer 50 is arranged. This control also makes it possible to be able to compensate in whole or in part the mechanical wave generated by each other piezoelectric transducer as it is perceived at the location where said piezoelectric transducer is arranged.

[0105] The invention is not limited to the example which has just been described.

[0106] A module integrating one or more piezoelectric transducers 50 is not necessarily used at the level of the primary sub-circuit 4. As a variant, the secondary resonant inductive cell 20 is associated with one or more piezoelectric transducers 50 within a module integrated into the secondary sub-circuit 6.

[0107] As a further variant, a module integrating one or more piezoelectric transducers 50 is present at the level of the primary sub-circuit 4 and a module integrating one or more piezoelectric transducers 50 is present at the level of the secondary sub-circuit 6.

Claims

Claims

1. Module (102) for inductive charging of an electric vehicle, comprising a body carrying a resonant inductive cell (10, 20), comprising at least one inductance (31) formed by an electrical conductor (33) wound on a core (34), the resonant inductive cell (10, 20) having a resonant frequency of less than 5kHz, characterized in that the module (102) carries at least one piezoelectric transducer (50) arranged inside the pattern defined by the electrical conductor (33) wound on the core (34).

2. Module according to claim 1, forming a mat for inductive charging of the electric vehicle, the mat being intended to be placed in or on the ground and / or to be electrically connected to a charging terminal itself electrically connected by wire to an electrical network.

3.

4. Module according to claim 1, being intended to be fixed to the vehicle. Module according to any one of the preceding claims, the resonant inductive cell (10, 20) also comprising a capacitor (32), forming with the inductance (31) a resonant LC cell.

5. Module according to any one of claims 1 to 3, the resonant inductive cell (10, 20) being constituted by the inductance (31).

6. Module according to any one of the preceding claims, comprising a single piezoelectric transducer (50).

7. Module according to any one of claims 1 to 5, comprising a plurality of piezoelectric transducers (50) distributed homogeneously in the pattern delimited by the wound electrical conductor (33) of the inductance (31).

8. Module according to any one of the preceding claims, the piezoelectric transducer (50) being supplied by a sinusoidal voltage whose frequency is equal to twice the resonant frequency of the resonant inductive cell (10, 20).

9. Assembly comprising: - an inverter / rectifier (21, 23) comprising at least two switching arms, each switching arm comprising two electronic switches arranged on either side of a midpoint, and and, - the module (102) according to any one of the preceding claims, the resonant inductive cell (10, 20) being mounted between two midpoints of the inverter / rectifier (21, 23),

10. An assembly according to claim 9, the module being according to claim 5, the switching arms of the inverter / rectifier (21, 23) being controlled so that the voltage across the AC input of this inverter / rectifier (21, 23) emulates the presence of a capacitor connected in series with the resonant inductive cell (10, 20).

11. An assembly according to claim 9 or 10, comprising an electrical energy storage unit connected to the terminals of the DC input of the inverter / rectifier (23), the inverter / rectifier being controlled so as to perform an impedance matching of the impedance on the AC input of this inverter / rectifier (23), independently of the impedance of the electrical energy storage unit (2).

12. Method for reducing vibrations in a module (102) for the inductive charging of an electric vehicle, comprising a body carrying a resonant inductive cell (10, 20) comprising at least one inductance (31) formed by an electrical conductor (33) wound on a core (34), the resonant inductive cell (10, 20) having a resonant frequency of less than 5 kHz, method in which: - the phase and / or the amplitude of the mechanical wave generated by magnetostriction in the body due to the flow of current in the electrical conductor (33) are measured, and - at least one piezoelectric transducer (50) is positioned inside the pattern defined by the electrical conductor (33) wound on the core (34) and this piezoelectric transducer (50) is controlled, this positioning and / or this control being determined to generate a mechanical wave compensating in whole or in part said mechanical wave generated by magnetostriction in the body.

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