Device for recovering electrical energy by converting mechanical energy

Abstract

The proposed recovery device comprises a stator (11), a slide (12), return means (13), a supporting platform (14), a chassis (15) and an electrical pulse integration circuit (16). It constitutes a magnetically bistable device which, by construction, is able to ensure that the amount of energy collected by integration of each electric pulse it generates is controlled and substantially constant. It has higher performance than previous solutions, is easily adaptable in dimensions, and has a manufacturing and maintenance cost that is low enough that it can be produced on an industrial scale and deployed widely.

Description

[0001] “Device for recovering electrical energy by converting mechanical energy”

[0002] TECHNICAL FIELD OF THE INVENTION

[0003] The present invention relates to the field of mechanical energy conversion and electrical energy recovery, and more particularly to the field of devices for recovering electrical energy by converting mechanical energy. The present invention finds application in numerous fields, and in particular in the field of energy recovery at the level of road infrastructures by vehicles passing over the device.

[0004] STATE OF THE ART

[0005] There are several systems for converting mechanical energy into electrical energy of the impulsive type. In this sense, these systems are distinguished from oscillating systems, which are discussed below. Some of these impulsive systems are based on traditional electromagnetic couplings and have, as main drawbacks, their lack of compactness and high maintenance cost. Some of these impulsive systems based on traditional electromagnetic couplings also involve gear devices and have, as main drawbacks, a large volume, low reliability, difficult integration of the generated electrical pulses and a lack of techno-economic viability, which explains why they have often remained at the prototype stage and have never been significantly deployed.Other impulsive systems are based on the use of piezoelectric materials and have, as main disadvantages, their low performance, although they are compact and inexpensive, and require little or no maintenance.

[0006] There are also systems for recovering electrical energy by converting mechanical energy which, unlike impulsive systems, are oscillating and potentially operate with small displacements and in the absence of rotating parts. Such systems are for example described in the patent documents referenced WO 2021 / 260711 A1, US 2020 / 0119619 A1, US 2015 / 0188389 A1 and US 2008 / 0164701 A1.

[0007] Some of these systems may comprise a stator, a slider, return means, a support platform, a chassis and an electrical pulse integration circuit: a. The stator being fixedly mounted on the chassis and comprising a first part and a second part superimposed and spaced apart from each other in a direction defined by a biasing axis of the return means, b. The slider, integral with the support platform, being mounted mobile in translation, relative to the stator, in the direction defined by the biasing axis of the return means and between a so-called rest position and a biasing position of the return means, and c. The slider and the stator having electromagnetic properties such that each translation of the slider between its rest position and its biasing position of the return means generates an electrical pulse that the electrical pulse integration circuit is configured to integrate.

[0008] These systems aim to convert the mechanical energy generated by any translational movement of the slide in the stator, regardless of the amplitude and speed of oscillation of the slide.

[0009] If these oscillating systems can be considered as offering an advantageous compromise between the main disadvantages of traditional electromagnetically coupled impulsive systems and the main disadvantages of impulsive systems based on the use of piezoelectric materials, their low deployment shows that it is still desirable to develop other solutions, and in particular more ecological, less expensive, more robust and efficient solutions, and above all allowing the obtaining of higher electrical energy production values. The present invention aims to provide such a solution, and in particular an even more advantageous compromise.

[0010] More particularly, the present invention aims to provide a device for recovering electrical energy by converting mechanical energy having higher performance than previous solutions.

[0011] Another objective of the present invention is to propose a device for recovering electrical energy by converting mechanical energy which is easily adaptable to different scales, and in particular from the macroscopic scale (of the order of a cubic decimeter) to the microscopic scale (of the order of a cubic micrometer).

[0012] Another objective of the present invention is to propose a device for recovering electrical energy by converting mechanical energy whose size remains moderate and / or whose manufacturing and maintenance cost remains sufficiently low, to allow their industrial production and their wide deployment, while preferably presenting higher performances than previous solutions.

[0013] SUMMARY OF THE INVENTION

[0014] To achieve this objective, according to a first aspect, a device for recovering electrical energy by converting mechanical energy is provided, in accordance with the preamble above, is essentially such that: a. One of the slider and each of the first and second parts of the stator comprises a permanent magnet and two extension elements made of a ferromagnetic material, the two extension elements extending respectively on either side of the permanent magnet in a direction substantially perpendicular to the axis of stress of the return means, b. The first and second parts of the stator define, between them, a housing accommodating, with an air gap, the slider, c. So that, when a mechanical force greater than a determined threshold is exerted on the support platform: i. the slider leaves its rest position, generating an electrical pulse in that of the first and second parts of the stator from which the slider moves away, and ii.the slider approaches its position of stressing the return means, generating at least one electrical pulse in that of the first and second parts of the stator which the slider approaches, and d. So that, when the mechanical force is no longer exerted on the support platform: i. the slider leaves its position of stressing the return means by relaxing the return means, generating at least one electrical pulse in that of the first and second parts of the stator which the slider moves away from, and ii. the slider returns to its rest position, generating at least one electrical pulse in that of the first and second parts of the stator which the slider approaches.

[0015] These are thus four electrical pulses which are integrated by the integration circuit at each return trip of the slide, that is to say at each passage of the slide from its rest position to its position of solicitation of the return means and, conversely, from its position of solicitation of the return means to its rest position.

[0016] More particularly, the permanent magnet of the slider creates, when the slider is close to either of the first and second parts of the stator, a magnetic field circulating through the slider and the part of the stator to which the slider is close; moving the slider away from either part of the stator disturbs the magnetic field circulating in the part of the stator from which the slider is moving away and generates an integrable electric pulse, and, conversely, moving the slider closer to either part of the stator disturbs the magnetic field circulating in the part of the stator to which the slider is approaching and generates an integrable electric pulse.

[0017] Thus, it appears that the proposed recovery device exploits, four times per round trip of the slide, the variation in reluctance of each of the magnetic circuits formed in turn by the slide and one of the two parts of the stator. Each electrical pulse generated corresponds to a quantity of energy, so that the integration of each electrical pulse can for example induce the storage of a quantity of energy corresponding to the electrical pulse.

[0018] Furthermore, it is understood from the above that the proposed recovery device is a magnetically bistable device, and that, in this sense, it is distinguished from oscillating devices for recovering electrical energy by converting mechanical energy, which aim in particular to recover all quantities of energy induced by all forces exerted on the support platform, including the smallest, or even the slowest. Unlike such oscillating devices, the recovery device proposed here makes it possible, by construction, to ensure that the quantity of energy collected by integration of each electrical pulse generated is controlled and substantially constant.Furthermore, the proposed device can be configured so that each of the four electrical pulses generated by the back-and-forth movement of the slider is controlled and substantially identical to the other three; consequently, the integration of any one of the four electrical pulses can be carried out by a simple integration circuit, relative to the integration circuit implemented by certain oscillating devices, and an amount of energy substantially equal to that generated by the other three pulses can be stored.

[0019] More specifically, the amount of energy collected by integrating each generated electric pulse depends on the various characteristics that define the recovery device, and not on an amplitude or speed of oscillation movements of the slide, this at the cost of a constraint consisting in that the support force on the platform must exceed a threshold to be able to drive the slide in translation. The value of this threshold is determined by various characteristics that define the recovery device. Therefore, the value of the threshold defines, at least in part, the amount of energy collected by integrating each generated electric pulse.

[0020] A second aspect of the invention relates to a system for recovering electrical energy by converting mechanical energy comprising at least one recovery device as introduced above and at least one piece of furniture, for example urban furniture, intended to be fixed to a system installation site and having at least one housing suitable for housing at least one recovery device as introduced above.

[0021] BRIEF DESCRIPTION OF THE FIGURES

[0022] The aims, objects, as well as the characteristics and advantages of the invention will emerge more clearly from the detailed description of an embodiment thereof which is illustrated by the following accompanying drawings in which:

[0023] Figure 1 represents a schematic view of an embodiment of the recovery device according to the first aspect of the invention.

[0024] Figure 2 shows a perspective view of an interior part of the recovery device according to a first embodiment of the first aspect of the invention.

[0025] Figure 2A shows a perspective view of an interior portion of the recovery device according to a variant of the first embodiment illustrated in Figure 2.

[0026] Figure 3 represents a perspective view from the outside of a part of the recovery device according to the embodiment illustrated in Figure 2. Figure 4A schematically represents an exploded view of an embodiment of the connectors implemented to functionally connect together the electrical pulses of different induction sub-coils of the recovery device according to an embodiment of the first aspect of the invention by means of an electrical connection pin.

[0027] Figure 4B schematically represents different ways of connecting together the induction sub-coils illustrated in Figure 4A; the implementation of the series and parallel electrical configurations of the induction sub-coils of the recovery device is illustrated by the two boxes superimposed on each other on the left of Figure 4B.

[0028] Figure 5 represents substantially the perspective view illustrated in Figure 2 and graphically illustrates an example of the relationship between the external force F ext to be exerted on the support platform to move the slide and the magnetic force of attraction F ma between the slider and the part of the stator to which it is closest, this relationship being determined in particular by the stiffness k spr return means so as to substantially optimize the recovery device according to the first aspect of the invention.

[0029] Figure 6A illustrates an embodiment of an integration circuit of the recovery device according to an embodiment of the first aspect of the invention.

[0030] Figure 6B illustrates an embodiment of a test circuit of the recovery device according to an embodiment of the first aspect of the invention.

[0031] Figure 7 illustrates a perspective view of an exploded portion of the recovery device according to the embodiment illustrated in Figure 3.

[0032] Figures 8A and 8B each illustrate an alternative form of slider and stator parts of a recovery device according to an embodiment of the first aspect of the invention.

[0033] Figure 9 represents a partial schematic perspective view of the stator and the slider of the recovery device according to the embodiment illustrated in Figure 8A and illustrates the different dimensions of interest as regards the sizing of these parts of the device between them.

[0034] Figure 10 is a schematic front view of each part of the stator, the slider and the support platform of the recovery device according to the embodiment illustrated in Figure 8A.

[0035] Figure 11A illustrates the closed magnetic field formed by the slider with the upper part of the stator, when these two elements of the recovery device are in direct contact with each other. Figure 11B illustrates the closed magnetic field formed by the slider with the lower part of the stator, when these two elements of the recovery device are in direct contact with each other.

[0036] Figures 12A-12E illustrate the deformation of the magnetic field at different stages of a forward translational movement of the slider, from the configuration illustrated in Figure 6A, to the configuration illustrated in Figure 6B.

[0037] Figures 13A to 13D are schematic front views of the stator and the slider of the recovery device according to an embodiment of the first aspect of the invention, at different stages of the back-and-forth translational movement of the slider.

[0038] Figure 14 is read superimposed on Figures 13A to 13D. It illustrates the moments during the back-and-forth translational movement of the slide during each of which an electric pulse is generated, this illustration taking the form of two electrograms superimposed on each other, the upper electrogram relating to the electric pulses generated in the upper part of the stator and the lower electrogram relating to the electric pulses generated in the lower part of the stator.

[0039] Figure 15 illustrates an electrogram resulting from the addition of the two electrograms illustrated in Figure 14, after rectification of one of the two electrical pulses generated in each part of the stator, said rectification being for example obtained by implementing a diode bridge as illustrated in Figure 6A.

[0040] Figure 16A is a graph illustrating changes in the instantaneous power produced (in Watts), the power density (in Watts per square meter and milliwatts per cubic centimeter), the energy converted (in Joules) and the efficiency (in percentage) as a function of the resistance value R ext of an electrical characterization circuit of a prototype of the device according to the first embodiment of the invention; each illustrated evolution corresponds to a parallel and / or series arrangement of three induction sub-coils wound around the ferromagnetic core of each of the parts of the stator. The characterized prototype has dimensions of 73x108x93 mm3= 0.733 dm3, a magnet made of Nd2Fe14B (h m = l m = 5 mm, w=50 mm), inductance coils L coüs =2x2.5 Henry (in series) and springs of stiffness / c spr =4x90 N / mm. This device is actuated with an external force F ma =900 N by traveling a displacement of xmM =2.5mm (for mechanical energy: E in =2.25 J), producing under non-optimized conditions an electrical energy E out =0.25 J.

[0041] Figure 16B is a graph illustrating the evolution of a voltage peak (in Volts) across the resistor R ext of the electrical characterization circuit of the prototype of the device according to the first embodiment of the invention as a function of the resistance value R ext , each illustrated evolution corresponds to one of the parallel and / or series arrangements of three induction sub-coils wound around the ferromagnetic core of each of the parts of the stator which are considered in figure 16A.

[0042] Figure 16C is a graph illustrating changes in the electric current (in Amperes) of the current across the resistor R extof the electrical characterization circuit of the prototype of the device according to the first embodiment of the invention as a function of the resistance value R ext ; each illustrated evolution corresponds to one of the parallel and / or series arrangements of three induction sub-coils wound around the ferromagnetic core of each of the parts of the stator which are considered in figure 16A.

[0043] Figure 17A is a graph showing the time evolution of the voltage (in volts) across the terminals of the diodes of a diode bridge forming part of the integration circuit of the recovery device according to the first aspect of the invention and the time evolution of the voltage (in volts) accumulated across a capacitor forming part of the integration circuit of the recovery device according to the first aspect of the invention.

[0044] Figure 17B is a graph showing the evolution of the stored energy as a function of the value of the capacitance of the integration circuits of the recovery device according to the first aspect of the invention for a given configuration of the connections between sub-coils constituting the induction coil of each of the two parts of the stator of the recovery device according to the first aspect of the invention.

[0045] Figure 18A shows a perspective view of a portion of a recovery system according to an embodiment of the second aspect of the invention.

[0046] Figure 18B shows an exploded view of the portion of the recovery system according to the embodiment illustrated in Figure 18A.

[0047] Figure 19A shows a perspective view of a portion of a recovery system according to an alternative embodiment of the second aspect of the invention to that illustrated in Figure 18A.

[0048] Figure 19B shows an exploded view of the portion of the recovery system according to the embodiment illustrated in Figure 19A.

[0049] The drawings are given by way of example and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate the understanding of the invention and are not necessarily to the scale of practical applications.

[0050] DETAILED DESCRIPTION OF THE INVENTION

[0051] Before commencing a detailed review of embodiments of the invention, optional features which may optionally be used in combination or alternatively are set out below:

[0052] According to one example, the first stator part and the second stator part may be fixed in position relative to each other.

[0053] According to one example, the slide and the support platform can be mechanically connected to the chassis via the return means.

[0054] According to one example, the return means may comprise at least one spring, for example helical.

[0055] According to one example, the slider in one and / or the other of its rest position and its position of stressing the return means can form with the part of the stator to which it is closest a support for a closed magnetic field induced by the permanent magnet. Preferably, said support is of a substantially constant section.

[0056] According to one example, at least one of the rest and biasing positions of the return means may be a contact position, direct or indirect, between the two extension elements of the slide and a corresponding one of the first and second parts of the stator.

[0057] In addition or as an alternative to the previous example, the recovery device may further comprise a stop arranged so as to oppose contact between the slider and the part of the stator to which the slider is close when the slider is in its rest position. The magnetic attraction force F ma between the slider and the part of the stator to which the slider is close when it is in the rest position of the return means, and therefore the support force F ext required to move the slide, can be reduced in a controlled manner.

[0058] According to one example, the threshold beyond which the mechanical force exerted on the support platform induces the movement of the slider can be determined proportionally to an electromagnetic attraction force between the slider in its rest position and the part of the stator to which the slider is close when the slider is in its rest position. In addition, the return means can be configured so that they do not generate, on the slider, a return force towards the rest position of the return means, before the slider has moved a non-zero distance x spr from the rest position of the return means.

[0059] According to one example, the stiffness of the return means can be configured to apply, on the slider in its position of biasing the return means, a return force towards its rest position greater than an electromagnetic attraction force between the slider and the part of the stator to which the slider is close when it is in its position of biasing the return means. According to one example, the slider comprising the permanent magnet and the two extension elements made of a ferromagnetic material, each part of the stator can comprise a ferromagnetic core and at least one induction coil wound around a central portion of the ferromagnetic core, each electrical pulse generated in a part of the stator taking the form of an electric current flowing in each induction coil of this part of the stator.More particularly, each ferromagnetic core of each stator portion may have a U-shape and the ends of the U-shape of one of the first and second stator portions face those of the U-shape of the other of the first and second stator portions. Alternatively or additionally, the slider may have an H-shape comprising side bars joined together by a central bar, the permanent magnet of the slider forming a portion of the central bar of the H-shape and the two extension elements forming the side bars of the H-shape and completing the central bar of the H-shape. The number of turns and the cross-section of the conductive wire of each induction coil may be configured so as to adapt the impedance thereof.

[0060] According to one example, the extension elements may extend from the permanent magnet via faces of the permanent magnet which are opposite each other in a magnetization direction of the permanent magnet, the latter being substantially perpendicular to the stress axis of the return means.

[0061] In one example, the slider including the permanent magnet and the two extension members made of a ferromagnetic material, the slider and the first and second stator portions may be configured such that the permanent magnet of the slider does not contact one of the first and second stator portions, regardless of the position of the slider.

[0062] According to one example, the circuit for integrating the electrical pulses may comprise a diode bridge and a capacitor, the diode bridge being configured, downstream of the capacitor, so that all the electrical pulses have the same orientation and the capacitor being capable of storing a quantity of energy corresponding to each electrical pulse generated.

[0063] According to one example, the frame may be configured to allow the device to be fixed to an installation site or to furniture, for example street furniture, intended to be fixed to an installation site.

[0064] According to one example, the recovery device may be free of at least one of: a. a piezoelectric component, b. a rotating part, c. a device for self-centering the slide relative to the stator, and d. a device for transmitting movement from a motor shaft to a receiving shaft.

[0065] The term "return means" means an elastic element, for example made of steel, capable of deforming by traction and / or compression, by storing energy in potential form to restore it by returning to its initial shape. The return means are typically such that their deformation occurs along a determined stress axis. For example, when the return means comprise a helical spring, the stress axis is typically defined by the axis of the spring.

[0066] A "closed magnetic circuit" means a magnetic circuit containing ferromagnetic parts that channel the magnetic flux in this circuit.

[0067] With reference to Figure 1, the device 1 for recovering electrical energy by converting mechanical energy according to the first aspect of the invention comprises a stator 11, a slider 12, return means 13, a support platform 14, a chassis 15 and an integration circuit 16 for electrical pulses. In the other appended figures, parts of the recovery device 1 according to the first aspect of the invention are often represented. When only the integration circuit 16 for electrical pulses is missing, the illustrated parts of the recovery device 1 according to the first aspect of the invention are referenced in a grouped manner by the reference numeral 1', as in Figure 1.These remaining parts 1' are in particular included by the device as partially illustrated in Figure 3, this illustration however only showing a part of the support plate 14 and the chassis 15; the stator 11, the slider 12 and the return means 13 being concealed by the support plate 14 and the chassis 15. By way of non-limiting example, Figure 7 shows an exploded view of a part of the set of elements T of the recovery device 1 which makes it possible to illustrate a way in which the stator 11, the slider 12 and the return means 13 can be arranged in the chassis 15 and relative to the support plate 14 and.

[0068] With reference to Figure 10, the stator 11, composed of two parts referenced 111 and 112, is fixedly mounted on the chassis 15. A first part 111 of the stator 11 and a second part 112 of the stator 11 are superimposed and spaced apart from each other in a direction (illustrated by the double arrow) defined by the axis of stress of the return means 13. The slider 12 is for its part integral with the support platform 14 and is mounted movable in translation, relative to the stator 11, in the direction defined by the axis of stress of the return means 13. In Figure 10, the slider 12 is in a so-called rest position of the return means 13; the slider 12 is then close to, or even in contact with, the first, upper part 111 of the stator 11.When the slide 12 is brought, according to its translational movement, into a position close to, or even in contact with, the second, lower part 112 of the stator 11, the slide 12 is in a position known as a position of stress on the return means 13; the latter then tend to push the slide 12 into the rest position of the return means 13.

[0069] The stator 11 and the slider 12 have electromagnetic properties such that each translation of the slider 11 between its rest position and its position of stressing the return means 13 generates at least one electrical pulse that the electrical pulse integration circuit 16 is configured to integrate.

[0070] With reference to Figure 2, and according to a preferred embodiment of the invention, the slider 12 may comprise a permanent magnet 121, for example based on neodymium (for example of formula Nd2Fei4B) and two extension elements 122 and 123 made of a ferromagnetic material (or ferrimagnetic, these two compositions possibly being grouped under the name “soft magnetic material”). The two extension elements 122 and 123 of the slide 12 extend respectively on either side of the permanent magnet 121 in a direction substantially perpendicular to the axis of stress of the return means 13. The first and second parts 111 and 112 of the stator 11 define, between them, a housing accommodating, with an air gap 110, the permanent magnet 121 and the two extension elements 122 and 123 of the slide 12.

[0071] Still with reference to Figure 2, each ferromagnetic part 111, 112 of the stator 11 comprises a ferromagnetic core 1111, 1121 and at least one induction coil 1112, 1122 wound around a central portion of the ferromagnetic core 1111, 1121. Each electrical pulse generated in a ferromagnetic part 111, 112 of the stator 11 takes the form of an electric current flowing in each induction coil 1112, 1122 of this ferromagnetic part 111, 112 of the stator 11. The ferromagnetic cores are for example based on soft magnetic cast iron. The coils are for example made of a winding of copper wire, for example having a diameter substantially equal to 80 μm.

[0072] In Figure 2A, an embodiment of the stator 11 and the slider 12 is illustrated which is an alternative to that illustrated in Figure 2. This alternative shows that the thickness w (see Figure 9) over which the stator 11 and the slider 12 extend can vary to the point of changing the shape ratio of the assembly, without making the recovery device 1 according to the first aspect of the invention dysfunctional.

[0073] The embodiment illustrated in Figure 2 corresponds substantially to that illustrated in Figure 8A; in the latter, a helical spring is also shown as return means 13 and a support 14' on the helical spring, this support 14' being able to be seen as a schematic representation of the support platform 14 to which it is considered to be integral. According to the embodiment illustrated in Figure 8A, each ferromagnetic core 1111, 1121 of each part 111, 112 of the stator

[0074] 11 has a U-shape and the ends of the U-shape of the first part 111 of the stator 11 face those of the U-shape of the second part 112 of the stator 11. Alternatively, and as illustrated in FIG. 8B, the slider 12 may have an H-shape comprising side bars joined together by a central bar, the permanent magnet 121 of the slider 12 forming a part of the central bar of the H-shape and the two extension elements 122 and 123 forming the side bars of the H-shape and completing the central bar of the H-shape. Note here that these alternatives can be combined with each other.

[0075] It is clear from the various figures already detailed that the extension elements 122 and 123 of the slide 12 extend, whatever the embodiment envisaged, from the permanent magnet 121 by faces of the permanent magnet 121 which are opposite each other according to a magnetization direction of the permanent magnet 121 (defined by the arrow drawn on the permanent magnet 121 illustrated in FIGS. 2, 2A, 8A, 8B and 9). The magnetization direction of the permanent magnet 121 is substantially perpendicular to the axis of stress of the return means 13.It is also apparent from the various figures already detailed that the permanent magnet 121, the extension elements 122 and 123, and the first and second parts 111 and 112 of the stator 11 can advantageously be configured so that the permanent magnet 121 of the slider 12 does not come into contact with one of the first and second parts 111 and 112 of the stator 11, regardless of the position of the slider 12; while this may result in the loss of magnetic field lines, and consequently significantly reduce the performance of the recovery device 1, it does, however, provide a simple method for reducing the external force required for the device to operate.

[0076] Figure 9 illustrates the different parameters characterizing the stator 11 and the slider

[0077] 12 constituting a part of the recovery device 1 according to its embodiment illustrated in Figure 2, or in Figure 2A. These different parameters were set as follows to produce a functional prototype of the recovery device 1 according to the first aspect of the invention: a- Xmax = e = 2.5 mm; b. di — cif c. l m = 15 mm; d. w = 50 mm; e. h a = 4.5 mm; f. h s = 57 mm; g. l s = 51 mm.

[0078] For these dimensions of the stator 11 and the slider 12, which are fixed here to be able to recover the energy produced by the passage of a bicycle on the recovery device 1: a. The magnetic attraction force F ma= F,)," = Pma that each part of the stator exerts on the slide 12 when they are in contact with each other is substantially equal to 900 N (where, as illustrated in Figure 11 A, F^a is the magnetic attraction force that is exerted between the first part 111 of the stator 11 and the slide 12 in the rest position of the return means, due to the permanent magnet 121 of the slide 12, and where, as illustrated in Figure 11 B, F^a is the magnetic attraction force that is exerted between the second part 112 of the stator 11 and the slide 12 in the biased position of the return means), due to the permanent magnet 121 of the slide 12), and b. The so-called input mechanical energy E in of the device amounts to approximately 2.25 J.

[0079] Furthermore, the inductance coils of the stator 11 are configured so as to have an inductance verifying s, in particular in terms of the number of windings, L coüs = 2 x 2.5 H

[0080] Furthermore, for these dimensions of the stator 11 and the slider 12, the return means 13 of the prototype advantageously take the form of 4 helical springs each having a stiffness k spr approximately equal to 90 N / mm.

[0081] A speed equivalent to the passage of a vehicle of v eqdef = ~2-5 km / h was used for laboratory tests, giving performance comparable to tests with cars passing at up to 20 km / h in a parking lot.

[0082] In particular due to the various aforementioned arrangements of the recovery device 1 according to the first aspect of the invention, and with reference to Figures 13A to 13D and Figure 14: a. when a mechanical force, or external force F ext , greater than a determined threshold, for example the value of the threshold being equal to that of the magnetic attraction force F^à 1that the first part 111 of the stator exerts on the slider 12 when they are in contact with each other, is exerted on the support platform 14: i. the slider 11 leaves its rest position (see figure 13A), generating an electrical pulse 21 (see figure 14) in the first part 111 of the stator 12, that is to say the part of the stator 11 from which the slider 12 moves away, and ii. the slider 11 approaches its position of stressing the return means 13 (see figure 13B), generating an electrical pulse 22 (see figure 14) in the second part 112 of the stator 11, that is to say the part of the stator 11 from which the slider 12 approaches; then b. when the mechanical force, or external force F ext, is no longer exerted on the support platform 14: i. the slide 12 leaves its position of stressing the return means 13 (Cf. figure 13C) by relaxation of the return means 13, by generating an electric pulse 23 (Cf. figure 14) in the second part 112 of the stator 11, that is to say the part of the stator 11 from which the slide 12 moves away, and ii. the slide 12 returns to the rest position of the return means 13 (Cf. figure 13D), by generating an electric pulse 24 (Cf. figure 14) in the first part 111 of the stator 11, that is to say the part of the stator 11 from which the slide 12 approaches.

[0083] Let us note here that the time between the generation of the electric pulse 23 and the generation of the electric pulse 24 illustrated in FIG. 14 is potentially directly proportional to the stiffness of the return means 13 alone. On the contrary, the time between the generation of the electric pulse 21 and the generation of the electric pulse 22 illustrated in FIG. 14 depends on the value of the support force exerted on the support platform 14.

[0084] As illustrated in Figures 11A and 11B, the slider 12 in each of the rest position and the biasing position of the return means 13 forms, with that of the first and second parts 111 and 112 of the stator 11 to which it is closest, a support for a closed magnetic field 31 and 32 induced by the permanent magnet 121 of the slider 12. Preferably, said support is of a substantially constant section, so as to avoid leakage of magnetic field lines. Figures 13A to 13D illustrate the way in which the magnetic field lines deform when passing from the closed magnetic field 31 illustrated in Figure 11A to the closed magnetic field 32 illustrated in Figure 11B, at different stages of a translational movement of the slider 12 from the rest position of the return means 13 to the biasing position of the return means 13.

[0085] If, in Figures 11A and 11B, each of the rest and biasing positions of the return means 13 is a position of direct contact between the two extension elements 122 and 123 of the slide 12 and a corresponding one of the first and second parts 111 and 112 of the stator 11, this example is not limiting of the recovery device 1 according to the first aspect of the invention. In particular, and with reference to Figure 9, the latter may further comprise a stop 17 arranged so as to oppose direct contact between the two extension elements 122 and 123 of the slide 12 and the first part 111 of the stator 11. It is thus possible to provide a physical gap between the slide 12 and the first part 111 of the stator 11 so that the magnetic attraction force F ma between the slider 12 and the first part 111 of the stator 11, and therefore the support force F extnecessary to move the slide 12, can if necessary be adjusted, and in particular reduced, in a controlled manner.

[0086] Referring to Figure 5, the threshold beyond which the mechanical force F ext exerted on the support platform 14 induces the displacement of the slide 12 can be determined from the electromagnetic attraction force F^à 1 (See also figure 11A) between the slide 12 in the rest position of the return means 13 and the first part 111 of the stator 11. More particularly, the recovery device 1 according to the first aspect of the invention can be configured so that it is not necessary to oppose a force that the return means 13 would exert on the slide 12 in the rest position of the return means 13. To do this, by noting x maxthe aforementioned air gap 110, the return means 13 can advantageously be configured so that they do not generate, on the slide 12, a return force towards the rest position of the return means 13, before the slide 12 has moved a non-zero distance x spr , preferably less than half of the air gap 110, or less than Xmax l^.

[0087] Alternatively or additionally, the stiffness of the return means 13 can be configured to apply, on the slide 12 in its position of stress of the return means 13, a return force towards its rest position greater than an electromagnetic attraction force F^à 2 (See figure 11 B) between the slide 12 and the second part 112 of the stator 11 when it is in its position of stressing the return means 13.

[0088] The stiffness of the return means 13 can therefore be advantageously configured so as to optimize the conversion that the recovery device 1 allows according to the first aspect of the invention, by not artificially increasing the threshold beyond which the mechanical force F ext exerted on the support platform 14 induces the movement of the slide 12, and while allowing the return of the slide 12 to the rest position of the return means 13 from the stress position of the return means 13 solely due to the return force exerted on the slide 12 by the return means 13.

[0089] To be recovered, the four pulses generated at each round trip of the slide 12 must be integrated. To this end, the integration circuit 16 of the electrical pulses 21, 22, 23 and 24 is provided; however, as appears from the electrical pulses 21, 22, 23 and 24 illustrated in FIG. 14, each generated electrical pulse has the same shape and therefore corresponds to the same quantity of energy, which simplifies the design of the integration circuit 16 to be implemented to recover the energy produced by the recovery device according to the first aspect of the invention, in particular in comparison with the oscillating recovery devices mentioned in the introduction. More particularly, the integration circuit 16 can here take the form of the circuit illustrated in FIG. 6A and then comprise a diode bridge 162 and a capacitor 163.The diode bridge 162 is then preferably arranged to rectify the two electrical pulses 21 and 23 generated which have an orientation opposite to the orientation of the two electrical pulses 22 and 24, and obtain the two electrical pulses 2T and 23' as illustrated in Figure 15. In this way, the capacitor 163 receives a rectified signal as illustrated in Figure 15, so as to be able to advantageously integrate the four electrical pulses 2T, 22, 23' and 24 generated by the recovery device 1 at each round trip of the slide 12. The result of this integration is illustrated in Figure 17A which shows the accumulation of the quantities of energy represented by each electrical pulse generated in the capacitor 163 of the integration circuit 16. Note here that the choice of the value of the capacitor 163 can influence the quantity of energy stored, in particular in the manner illustrated in Figure 17B.This parameter which constitutes the value of the capacitance 163 is therefore to be adjusted on a case-by-case basis, in a manner deemed known to the person skilled in the art, to optimize the recovery. Note here that FIG. 17A was obtained for a particular case according to which the induction coil 1112, 1122 of each part 111, 112 of the stator 11 is in fact made up of three induction sub-coils connected together in series and according to which the induction coil 1112 of the first part 111 of the stator 11 and the induction coil 1122 of the first part 112 of the stator 11 are connected together in parallel. It will also be noted, in view of the graph in figure 17B, that the efficiency (or effectiveness) of the prototyped device is directly proportional to the energy stored in the capacity of the integration device 16 and that it is envisaged that the recovery device 1, once optimized, will make it possible to achieve efficiencies greater than 6%.

[0090] It thus appears that, as illustrated in Figures 4A and 4B, each induction coil 1112, 1122 can be made up of a plurality of sub-coils that the person skilled in the art can, depending on the intended application, connect together in series (see Figure 4B). Let us further observe, in Figure 4A, that the electrical connection pin then comprises at least as many electrical connections as the sub-coils have ends. Figure 4A illustrates, in this case, a possible arrangement of the sub-coils constituting each of the induction coils of each part 111, 112 of the stator 11 relative to each of the ferromagnetic cores 1111 and 1121 of the stator 11.

[0091] Performance tests were carried out on the prototype described above, the results of which are illustrated in Figures 16 A to 16C, at least for each of the four electrical connection configurations between sub-coils which are illustrated in Figure 4B. More particularly, these tests were carried out by simulation or by measurement of the electric current and the electric voltage reaching a so-called external resistance R ext , as illustrated in Figure 6B, connected to the aforementioned remaining parts 1' of the prototyped recovery device in place of the integration circuit 16 illustrated in Figure 6A.

[0092] It is observed, in Figures 16B and 16C, that the recovery device 1 according to the first aspect of the invention can operate in a so-called electric current recovery mode when the value of the external resistance R extis relatively low, and typically less than 1000 Q for the prototype considered, or can operate in a so-called electrical voltage recovery mode when the value of the external resistance R ext is relatively large, and typically greater than 10,000 Q for the prototype considered. It is also observed that the recovered current and voltage have different values ​​depending on the different connection configurations between the sub-coils of each part 111, 112 of the stator 11; thus, these different possible configurations offer, to the person skilled in the art, a capacity for adaptation to the intended or encountered application case. It will be noted that as illustrated by the graph in FIG. 16A, the instantaneous power generated by the prototype reaches, as a function of the value of the external resistance R ext, more or less equivalent values ​​for the different configurations envisaged for connecting the sub-coils of each part 111, 112 of the stator 11 to each other.

[0093] It will be noted that the recovery device 1 according to the first aspect of the invention is advantageously free of at least one of: a. a piezoelectric component, even though the size of the proposed recovery device remains limited relative to existing solutions not comprising piezoelectric components, b. a rotating part, which explains in particular the absence of the need for lubrication of the proposed recovery device, c. a device for self-centering the slide relative to the stator, which contributes to the robustness of the proposed recovery device, and d. a device for transmitting a movement from a motor shaft to a receiving shaft, which again explains the absence of the need for lubrication of the proposed recovery device.

[0094] Finally, note that the proposed recovery device, as well as the associated system, offer for a given gain in power density a more ecological recovery solution than some of the existing solutions. In order to reduce the cost of electricity production, it is even possible to choose a permanent magnet 121 that is inexpensive, less efficient, but with a lower ecological impact, while allowing the same quantity of energy to be recovered with the increase in its dimensions while always keeping the advantage of the architecture in terms of power density.

[0095] As mentioned in the introduction, the present invention also relates, according to a second aspect of the invention, to an electrical energy recovery system 0 comprising a recovery device 1 according to the first aspect of the invention, the frame 15 of the recovery device 1 being able to be configured to allow the recovery device 1 to be fixed either directly to an installation site, or to furniture, for example urban furniture, intended to be fixed to said installation site. It is understood that more than one recovery device 1 can be arranged on the same installation site and possibly by means of the same furniture 10. It is then possible to mount between several recovery devices, in series, in parallel or in a mixed configuration.

[0096] Figures 18A and 18B illustrate a first exemplary embodiment of the recovery system 0 according to the second aspect of the invention in which a piece of furniture 10 has a housing 100 adapted to house therein a recovery device 1 according to the first aspect of the invention. This first exemplary embodiment is particularly suitable for burial in a span of a traffic roadway for example for motor vehicles, bicycles or pedestrians, the surface of the furniture 10 constituting in part the surface of the roadway. Another exemplary embodiment is illustrated in Figures 19A and 19B which is more intended to constitute a protuberance relative to a traffic roadway on which it is intended to be installed. In this way, the recovery system 1 can also constitute a speed bump.

[0097] The proposed recovery device 1, and in particular the one that was prototyped to demonstrate the feasibility and the interest that the proposed device has, still need to be optimized, if necessary, but, as demonstrated above, are already promising. Indeed, although we do not optimize, they are already competitive compared to traditional recovery systems and emerging technologies. With a reduced cost and great robustness, the proposed recovery device is advantageously customizable or modular, in particular in terms of the sizing of the surfaces and other volumes involved (at least ranging from cubic micrometers to cubic decimeters), depending on the intended application.

[0098] The integration of the recovery system 0 is easy regardless of the environment, particularly urban (road, railway, bicycle crossing, playground, sports center, etc.) of its installation. Its use can also be diverted, for example, to measure traffic flow on a road, and / or to measure at least one of the weight and / or the speed of the vehicles traveling on the recovery device 1.

[0099] It also emerges from the above that the recovery device 1 according to the first aspect of the invention offers high performance for a relatively small dimensioning and small deformations, or more particularly small displacements (over the distance constituted by the air gap 110), compared to the recovery device known from the prior art.

[0100] The invention is not limited to the embodiments or applications previously described and potentially extends to other embodiments or applications. For example, on a larger scale, the device can be used in the presence or absence of springs in applications where the source is impulsive or oscillatory. For example, each fixed part of the device (each of the first part and the second part of the stator) and the movable part of the device (the slider) take, in the preceding description, a configuration which can be interchanged with the other part, without in any way altering the operation and performance of the recovery device.Potentially, only the position of the spring contact would need to be adapted to allow the aforementioned permutation, where the elements described above as constituting each part of the stator would be movable and the elements described above as constituting the slider would be fixed.

Claims

CLAIMS 1. Device (1) for recovering electrical energy by converting mechanical energy, the device comprising at least one stator (11), a slider (12), return means (13), a support platform (14), a chassis (15) and an integration circuit (16) of electrical pulses (2): • The stator (11) being fixedly mounted on the chassis (15) and comprising a first part (111) and a second part (112) superimposed and spaced apart from each other in a direction defined by a stress axis of the return means (13), • The slide (12), integral with the support platform (14), being mounted to move in translation, relative to the stator (11), in the direction defined by the axis of stress of the return means (13) and between a so-called rest position and a position of stress of the return means (13), and • The stator (11) and the slider (12) having electromagnetic properties such that each translation of the slider (11) between its rest position and its position of stressing the return means (13) generates an electric pulse (2) that the integration circuit (16) of electric pulses (2) is configured to integrate, The device (1) being characterized in that: • One of the slide (12) and each of the first and second parts (111, 112) of the stator (11) comprises a permanent magnet (121) and two extension elements (122, 123) made of a ferromagnetic material, the two extension elements (122, 123) extending respectively on either side of the permanent magnet (121) in a direction substantially perpendicular to the axis of stress of the return means (13), • The first and second parts (111, 112) of the stator (11) define, between them, an accommodating housing, with an air gap, the slider (12), • So that, when a mechanical force greater than a determined threshold is exerted on the support platform (14): i. the slider (11) leaves its rest position, generating at least one electrical pulse (21) in that (111) of the first and second parts (111, 112) of the stator (12) from which the slider (11) moves away, and ii. the slider (11) approaches its position of stressing the return means (13), by generating an electric pulse (22) in that (112) of the first and second parts (111, 112) of the stator (11) which the slider (11) approaches, and • So that, when the mechanical force is no longer exerted on the support platform (14): i. the slide (12) leaves its position of stressing the return means (13) by relaxation of the return means (13), by generating an electrical pulse (23) in that (112) of the first and second parts (111, 112) of the stator (11) from which the slide (12) moves away, and ii. the slide (12) returns to its rest position, by generating an electrical pulse (24) in that (111) of the first and second parts (111, 112) of the stator (11) from which the slide (12) approaches.

2. Device (1) according to the preceding claim, in which the slide (12) in one and / or the other of its rest position and its position of stressing the return means (13) forms, with that of the first and second parts (111, 112) (111, 112) of the stator (11) to which it is closest, a support for a closed magnetic field (31, 32) induced by the permanent magnet (121).

3. Device (1) according to the preceding claim, in which said support is of a substantially constant section.

4. Device (1) according to any one of the preceding claims, in which at least one of the rest and biasing positions of the return means (13) is a contact position between the two extension elements (122, 123) of the slide (12) and a corresponding one of the first and second parts (111, 112) of the stator (11).

5. Device (1) according to any one of the preceding claims, further comprising a stop (17) arranged so as to oppose direct contact between the slide (12) and the part (111) of the stator (11) to which the slide (12) is close when the slide (12) is in its rest position.

6. Device (1) according to any one of the preceding claims, in which the threshold beyond which the mechanical force exerted on the support platform (14) induces the movement of the slide (12) is determined from an electromagnetic attraction force F,)," between the slide (12) in its rest position and the part (111) of the stator (11) whose slider (12) is close when the slider (12) is in its rest position.

7. Device (1) according to the preceding claim, in which the return means (13) are configured so that they do not generate, on the slide (12), a return force towards the rest position of the return means (13), before the slide (12) has moved a non-zero distance x spr from the rest position of the return means (13).

8. Device (1) according to any one of the preceding claims, in which the stiffness of the return means (13) is configured to apply, on the slide (12) in its position of stress of the return means (13), a return force towards its rest position greater than an electromagnetic attraction force F^à 2 between the slider (12) and the part (112) of the stator (11) to which the slider (12) is close when it is in its position of stressing the return means (13).

9. Device (1) according to any one of the preceding claims, wherein, the slide (12) comprising the permanent magnet (121) and the two extension elements (122, 123) made of a ferromagnetic material, each part (111, 112) of the stator (11) comprises a ferromagnetic core (1111, 1121) and at least one induction coil (1112, 1122) wound around a central portion of the ferromagnetic core (1111, 1121), each electrical pulse (21, 22, 23, 24) generated in a part (111, 112) of the stator (11) taking the form of an electric current flowing in each induction coil (1112, 1122) of this part (111, 112) of the stator (11).

10. Device (1) according to any one of the preceding claims, in which the extension elements (122, 123) extend from the permanent magnet (121) by faces of the permanent magnet (121) which are opposite each other in a direction of magnetization of the permanent magnet (121), the latter being substantially perpendicular to the axis of stress of the return means (13).

11. Device (1) according to any one of the three preceding claims, wherein, the slider (12) comprising the permanent magnet (121) and the two extension elements (122, 123) made of a ferromagnetic material, the slider (12) and the first and second parts (111, 112) of the stator (11) are configured so that the permanent magnet (121) of the slider (12) does not come into contact with one of the first and second parts (111, 112) of the stator (11), whatever the position of the slider (12).

12. Device (1) according to any one of the preceding claims, in which the integration circuit (16) of the electrical pulses (21, 22, 23, 24) comprises a diode bridge (162) and a capacitor (163), the diode bridge (162) being configured, downstream of the capacitor (163), so that all the electrical pulses (21, 22, 23, 24) are rectified in the same direction and the capacitor (163) being capable of storing an energy density corresponding to each electrical pulse (2T, 22, 23', 24) generated and, where appropriate, rectified.

13. Device (1) according to any one of the preceding claims, in which the frame (15) is configured to allow the device (1) to be fixed to an installation site or to furniture, for example urban furniture, intended to be fixed to an installation site.

14. Device (1) according to any one of the preceding claims, free from at least one of: • a piezoelectric component, • a rotating part, • a device for self-centering the slide relative to the stator, and • a device for transmitting movement from a motor shaft to a receiving shaft.

15. System for recovering (0) electrical energy by converting mechanical energy comprising at least one recovery device (1) according to any one of the preceding claims and at least one item of furniture (10), for example urban furniture, intended to be fixed to a site of installation of the system (0) and having at least one housing (100) adapted to house therein at least one recovery device (1) according to any one of the preceding claims.

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