Electrical power supply circuit of a vehicle electrical energy storage unit

Abstract

Power supply circuit (1) of an electrical energy storage unit (2), this power supply circuit comprising: - a primary sub-circuit (4), suitable for connection to a voltage network (5), and - a secondary sub-circuit (6), suitable for connection to an electrical energy storage unit (2), the primary sub-circuit (4) and the secondary sub-circuit (6) being configured so as to exchange electrical energy without contact by inductive coupling, the secondary sub-circuit (6) comprising: - a secondary inductive cell (20) for the exchange of electrical energy with the primary sub-circuit (4) without contact by inductive coupling, - an inverter / rectifier (23) suitable for performing 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), this inverter / rectifier (23) comprising at least two switching arms (24),each switching arm (24) comprising two electronic switches (12) arranged on either side of a midpoint (25), - a transformer (11), having a primary winding (13), and having at least one secondary winding (14), this secondary winding (14) being mounted between two midpoints (25) of the inverter / rectifier (23), and - a frequency matching stage (30), arranged between the secondary inductive cell (20) and the primary winding (13) of the transformer (11), this stage (30) being configured to modify the frequency between the voltage across the secondary inductive cell (20) and the voltage across the primary winding (13) of the transformer (11). Abbreviated figure: Fig. 1,

Description

Title of the invention: Power supply circuit for a vehicle electrical energy storage unit

[0001] The present invention relates to a contactless electrical power supply circuit for a vehicle electrical energy storage unit.

[0002] The electrical energy storage unit has, for example, a nominal voltage of 12V, 48V, 60V or more, for example greater than 300V, for example 400V, 800V or 1000V.

[0003] It is known to electrically power a vehicle electrical energy storage unit by contactless transmission using inductive coupling at a power of between 3 and 50 kW, when the vehicle is stationary or when it is moving. This power supply by contactless transmission is then carried out by means of distant electrical sub-circuits that are magnetically coupled and tuned to the same resonant frequency. The magnetically coupled sub-circuits each implement an LC-type resonant cell. However, to transmit a satisfactory power level, in particular several kW, it is necessary to operate at high frequencies, in particular of the order of 85 kHz or more, for the resonant frequency of each resonant sub-circuit. In addition, this type of solution requires operating at a short distance between the two sub-circuits.The frequency and power levels mentioned above, for implementation in kW, may also constitute a danger to the health of people exposed nearby, or a danger to the environment in general.

[0004] The solution according to the international application filed under No. PCT / EP2023 / 076297 on 09 / 22 / 2023 in the name of Valeo Systèmes de Contrôle Moteur, which is not part of the published state of the art, consists of applying an alternating voltage to the terminals of a primary inductive cell coupled by inductive coupling to a secondary inductive cell which, by impedance adaptation, makes it possible to transmit low-frequency electrical energy into an electrical energy storage unit, for example an electric vehicle battery. With such a solution, the transmissible power and the efficiency are limited by the value of the direct voltage at the input of the inverter / rectifier supplying the primary inductance cell and by the value of the voltage at the terminals of the electrical energy storage unit.In fact, due to this voltage value at the terminals of the electrical energy storage unit, a maximum current value in the secondary inductive cell must be respected, hence a limitation of the yield obtained.

[0005] There is a need to provide a power supply for a storage unit of electrical energy by contactless transmission which overcomes the aforementioned drawbacks.

[0006] The invention aims to meet this need and achieves this, according to one of its aspects, using an electrical power supply circuit for an electrical energy storage unit, this electrical power supply circuit comprising:

[0007] - a primary sub-circuit, capable of being connected to a voltage network, and

[0008] - a secondary sub-circuit, capable of being connected to an energy storage unit electric,

[0009] the primary sub-circuit and the secondary sub-circuit being configured so as to exchange electrical energy without contact by inductive coupling,

[0010] the secondary sub-circuit comprising:

[0011] - a secondary inductive cell for contactless exchange by inductive coupling of electrical energy with the primary sub-circuit,

[0012] - an inverter / rectifier capable of performing impedance matching of the impedance on the alternating input of this inverter / rectifier, independently of the impedance of the electrical energy storage unit, this inverter / rectifier comprising at least two switching arms, each switching arm comprising two electronic switches arranged on either side of a midpoint,

[0013] - a transformer, having a primary winding, and having at least one secondary bearing, this secondary winding being mounted between two midpoints of the inverter / rectifier, and

[0014] - a frequency adaptation stage, arranged between the secondary inductive cell and the primary winding of the transformer, this stage being configured to modify the frequency between the voltage across the secondary inductive cell and the voltage across the primary winding of the transformer.

[0015] The presence, in the secondary sub-circuit, of a transformer associated with the frequency adaptation stage makes it possible to combine the advantages of the presence of the transformer and the frequency adaptation stage by reducing their respective disadvantages so that the voltage across the terminals of the secondary inductive cell has a higher voltage, in particular higher than the voltage across the terminals of the electrical energy storage unit. This increases the efficiency of the contactless exchange of electrical energy by inductive coupling. Using the transformer combined with the frequency adaptation stage makes it possible to use a high-frequency transformer and to reduce the constraints on the electronic switches of the inverter / rectifier performing the impedance adaptation. This reduces the size and therefore the cost of the transformer and the electronic switches of this inverter / rectifier.

[0016] The transformer has, for example, a transmission ratio N of between 1 and 10, for example between 1.5 and 10, in particular between 2 and 5, for example 3, so that the current flowing in the primary winding of the transformer is equal to 1 / N times the current flowing in the secondary winding of the transformer.

[0017] The inverter / rectifier may comprise exactly two switching arms, and the transformer may comprise a single secondary winding mounted between the two midpoints of the inverter / rectifier. For example, no physical component is interposed between the two midpoints of the inverter / rectifier and the secondary winding of the transformer.

[0018] According to an exemplary implementation, the frequency adaptation stage may comprise two arms, in particular exactly two arms:

[0019] - a first arm comprising two impedances mounted on either side of a point middle, and

[0020] - a second switching arm comprising two pairs of electrical switches controllable electronic switches, each pair comprising two controllable electronic switches mounted in series, these two pairs being mounted on either side of a midpoint, and

[0021] the primary winding of the transformer can be mounted between the two midpoints of the frequency adaptation stage and / or the secondary inductive cell can be mounted in parallel with the two arms of the frequency adaptation stage.

[0022] According to this example of implementation, no physical component is for example mounted in series with the primary winding of the transformer between the two midpoints of the frequency adaptation stage.

[0023] Also according to this example, no physical component is for example mounted in series with the secondary inductive cell, in the parallel branch of the arms of the frequency adaptation stage.

[0024] In all of the above, the frequency adaptation stage can be controlled so that the frequency of the electric current flowing in the primary winding of the transformer is equal to K times the frequency of the electric current flowing in the secondary inductive cell. This increase in frequency can make it possible to reduce the size of the transformer. K can be between 1 and 100, being in particular between 1.5 and 10, in particular between 5 and 10.

[0025] According to the described implementation example, the impedances of the first arm can be capacitors.

[0026] Still according to the described implementation example, each pair of controllable electronic switches of the second arm can comprise two field effect transistors mounted in common source or common drain, or comprise bipolar or IGBT transistors mounted in common emitter or common collector.

[0027] Within a pair, the two transistors can be of opposite or the same doping. doping. In the case of field-effect transistors, one of these transistors may be an N-channel MOSFET while the other transistor in this pair is a P-channel MOSFET. In the case of bipolar transistors, one of these transistors is, for example, an NPN while the other transistor is a PNP.

[0028] Each pair of controllable electronic switches of the second arm of the frequency adaptation stage can make it possible to create a bidirectional cell in current and voltage.

[0029] When there are two transistors within each pair of the second arm of the frequency adaptation stage having opposite doping relative to each other, the transistor of the first pair and the transistor of the second pair both having the same doping may have the same positioning in their respective pair relative to the midpoint of the second arm. Each of these two transistors of the same doping is, for example, within its respective pair, the transistor mounted directly adjacent to this midpoint. Alternatively, these two transistors of the same doping may have different positions in their respective pair relative to the midpoint of the second arm.One of these transistors is for example the transistor of one of the pairs of the second arm directly adjacent to the midpoint while the other of these transistors is the transistor of the other of the pairs of the second arm which is not directly adjacent to this midpoint, the transistor of the other of the pairs which is directly adjacent to the midpoint having a different doping.

[0030] From one pair to another, and independently of their doping, the controllable electronic switches of different positioning relative to the midpoint of the second arm can have the same control. Thus:

[0031] - two electronic switches controllable with different positions by relative to the midpoint of the second switching arm, also called "first switches of this second switching arm" are for example controlled in PWM with the same duty cycle while the two other controllable electronic switches of the second switching arm, also called "second switches of this second switching arm", are kept closed for a given alternation of the voltage at the terminals of the secondary inductive cell, and

[0032] - the two second switches of the second switching arm are by example driven in PWM with the same duty cycle while the first two switches of the second switching arm are kept closed for the other alternation of the voltage across the terminals of the secondary inductive cell.

[0033] This command can be used to process each voltage polarity at the terminals of the secondary inductive cell.

[0034] The invention is not limited to the choice of bipolar transistors or transistors with field effect to realize pairs of controllable electronic switches of the second arm. Alternatively, the second arm of the frequency adaptation stage can use IGBTs.

[0035] In all of the above, the frequency adaptation stage may comprise, for each controllable electronic switch of the second arm, a diode mounted in anti-parallel.

[0036] The frequency adaptation stage may comprise, for each controllable electronic switch of the second arm, a capacitor connected in parallel. It is thus possible to switch each electronic switch of the second arm when the voltage across its terminals is zero, thus reducing switching losses.

[0037] In all of the above, the secondary inductive cell can be constituted by the series association of a capacitor and an inductance.

[0038] Alternatively, in all of the above, the secondary inductive cell may be constituted by an inductor, the switching arms of the inverter / rectifier and the second arm of the frequency adaptation stage being controlled so that the voltage across each arm of the frequency adaptation stage emulates the presence of a capacitor connected in series with the secondary inductive cell. Such a control making it possible to obtain this emulation is described in the application filed in France on June 2, 2023 by the Applicant under number 23 05573. The content of this application is incorporated by reference into the present application with regard to the control of the duty cycles of the switching arms of the inverter / rectifier. To obtain this emulation, the voltage across the first arm of the frequency adaptation stage can be controlled as a function of the current flowing in the secondary inductive cell.

[0039] The contactless exchange by inductive coupling of electrical energy can be done at a frequency lower than 5 kHz, for example lower than 3 kHz, or even lower than 2 kHz or 1 kHz, in particular still substantially equal to 400 Hz or 50 Hz. In this case, the inductance of the secondary inductive cell can be made of metal wire, such as copper. Such a metal wire is solid, as opposed to Litz wire. A solid metal wire does not have its cross-section hollowed out. Alternatively, this inductance of the secondary inductive cell is made of Litz wire.

[0040] In this variant, Litz wire is advantageously used to produce the inductance of the secondary inductive cell.

[0041] The inverter / rectifier comprises for example only two switching arms, and one of these two arms is 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 these two arms is 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 secondary winding of the transformer 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 secondary winding of the transformer and I is the current flowing through this secondary winding. 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.

[0042] Each switch of a switching arm is for example a controllable electronic switch.

[0043] Alternatively, each switching arm comprises two electronic switches, only one of which is controllable.

[0044] In all of the above, the secondary sub-circuit may comprise the electrical energy storage unit. The latter may be a lithium-ion type battery. This battery has, for example, a nominal voltage of 12V, 48V, 60V or more, for example greater than 300V, for example 400V, 800V or 1000V.

[0045] In all that follows, the primary sub-circuit may comprise:

[0046] - a primary inductive cell for contactless exchange by inductive coupling of electrical energy with the secondary inductive cell, and

[0047] - an inverter / rectifier comprising at least two switching arms, each switching arm comprising two electronic switches controllable on either side of a midpoint.

[0048] The secondary inductive cell and the primary inductive cell are advantageously chosen so that they have the same resonance frequency.

[0049] In all of the above, the primary inductive cell may be constituted by the series association of a capacitor and an inductor. Alternatively, and similarly to what has been mentioned in relation to the secondary inductive cell, the primary inductive cell may be constituted by an inductor, the switching arms of the inverter / rectifier of the primary sub-circuit being controlled so that the voltage across the AC input of this inverter / rectifier emulates the presence of a capacitor connected in series with the primary inductive cell.

[0050] In the case of a contactless exchange by inductive coupling of electrical energy at a frequency lower than 5 kHz, the inductance of the primary inductive cell can be made of metal wire, such as copper. Such a metal wire is solid, as opposed to Litz wire. A solid metal wire does not have its cross-section hollowed out. Alternatively, this inductance of the primary inductive cell is made of Litz wire.

[0051] Where appropriate, the primary sub-circuit may comprise another inverter / rectifier mounted upstream of the inverter / rectifier at the midpoints of which the primary winding of the transformer is mounted, and this other inverter / rectifier is used to rectify the AC voltage received from the network when the load is made from an AC voltage network. This other inverter / rectifier can then perform a power factor correction function. Such a correction allows, in a known way, that the current taken from the network is as close as possible to a perfect sine wave at the network pulse. This reduces the reactive current and the sub-harmonics which increase energy losses in conduction.

[0052] In all of the above, the electrical network provides, for example, a nominal effective voltage of 230V with a frequency of 50 Hz or 60 Hz. The electrical network is, for example, single-phase. The electrical network is, for example, a regional or national electrical network. Alternatively, it may be an independent local network, comprising, for example, one or more batteries powered by energy sources such as wind turbines, solar panels, fuel cells or hydroelectric generators.

[0053] As a further variant, the electrical network can provide a direct voltage.

[0054] The electrical circuit may comprise a control unit configured to control the switching arms of the primary sub-circuit and / or the secondary sub-circuit. For the purposes of the present invention, when an arm switches, each of its two controllable electronic switches is opened and closed in a complementary manner with the same switching frequency.

[0055] The control unit can be configured to control the different switching arms so as to selectively carry out:

[0056] - a charge of the electrical energy storage unit from the voltage network, Or

[0057] - a load of the voltage network from the electrical energy storage unit.

[0058] Thus, depending on the need, the exchange of electrical energy can be carried out in one direction or the other.

[0059] In all of the above, each switching arm of an inverter / rectifier comprises controllable electronic switches, in particular exclusively electronic switches which are controllable, and each controllable electronic switch is for example a transistor, for example bipolar, MOS or IGBT, or a thyristor. Each controllable electronic switch is for example bidirectional.

[0060] In all of the above, the control unit may be a digital processing circuit, for example an ASIC (Application-specific integrated circuit) or a microcontroller. This control unit may control all the switching arms of the electrical circuit, whether they belong to the primary subcircuit or secondary subcircuit.

[0061] The control unit may alternatively comprise a primary sub-circuit control module and a secondary sub-circuit control module.

[0062] Alternatively, each sub-circuit has its own control unit, the latter being able to be a digital processing circuit such as a microcontroller.

[0063] The invention also relates, according to another of its aspects, to a component for the electrical power supply of an electrical energy storage unit, comprising the electrical circuit as defined above, the component defining in particular a structure rigidly supporting the primary sub-circuit and the secondary sub-circuit. Such a component is commonly called an “on-board charger”. This component is capable of being embedded in a hybrid or electric vehicle.

[0064] The invention also relates, according to another of its aspects, to a device for supplying electricity to an electrical energy storage unit, comprising:

[0065] - a charging station for a hybrid or electric vehicle, in which is arranged the primary sub-circuit of the electrical circuit as defined above or to which this primary sub-circuit is electrically connected, and

[0066] - a component capable of being embedded in a hybrid or electric vehicle, in in which the secondary sub-circuit of the electrical circuit as defined above is arranged.

[0067] This terminal then receives electrical energy from an electrical network via a cable which can be a single-phase cable or a three-phase cable. In this case, the primary circuit and the secondary circuit are not integrated into the same physical component.

[0068] The invention may be better understood by reading the following description of a non-limiting example of its implementation and by examining the attached drawing in which:

[0069] [Fig.l] schematically represents an electrical power supply circuit according to an exemplary implementation of the invention, and

[0070] [Fig.2] schematically represents a variant of the electrical circuit of the [Fig.l].

[0071] [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 an electric or hybrid vehicle propulsion system.

[0072] This electrical power supply circuit 1 comprises:

[0073] - a control unit 3,

[0074] - a primary sub-circuit 4, capable of being connected to a voltage network 5, and

[0075] - a secondary sub-circuit 6, comprising the electrical energy storage unit 2.

[0076] 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.

[0077] The control unit 3 is for example a microcontroller or any digital processing unit.

[0078] In the example considered, the primary sub-circuit 4 comprises:

[0079] - a connector 9 capable of being connected to the electrical network,

[0080] - an inverter / rectifier 21 comprising here two switching arms 7, mounted in parallel and whose operation will be described below, and

[0081] - a primary inductive cell 10 whose operation will be described below.

[0082] The electrical network 5 is here represented in the form of a voltage network continuous 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. 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 60Hz or a three-phase voltage of 240V and a frequency of 60Hz, this list not being exhaustive. In the case where the network provides an alternating voltage, another inverter / rectifier not shown is provided between the network and the inverter / rectifier 21, this other inverter / rectifier providing for example a power factor correction function.

[0083] As can be seen in [Fig. 1], 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.

[0084] 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.

[0085] 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 ai.

[0086] The second arm 7 thus comprises two controllable electronic switches 12 and a second midpoint 8 to which the other terminal of the primary inductive cell 10 is connected and these two controllable electronic switches 12 are ordered according to a duty cycle a2.

[0087] In the example considered, no physical component is interposed between the two midpoints 8 of the inverter / rectifier 21 and the primary inductive cell 10.

[0088] The primary inductive cell 10 may be formed by the series association of: an inductor allowing the generation of magnetic energy, and a capacitor, to form a resonant cell. The inductor has for example a value between 100pH and 100mH and the capacitor has a capacitance between 10 nF and 1 mF. The inductor is for example produced by winding a copper wire, other than Litz wire.

[0089] In the variant shown in Figures 1 and 2, the primary 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 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

[0090] An example of a secondary sub-circuit 6 will now be described with reference to [Fig.l]. This secondary sub-circuit 6 comprises:

[0091] - a secondary inductive cell 20 for the exchange of energy without contact with the primary inductive cell 10,

[0092] - a frequency adaptation stage 30,

[0093] - a transformer 11, and

[0094] - an inverter / rectifier 23, capable of carrying out an adaptation of the impedance equivalent on its alternating input, so as to vary this impedance independently of the impedance of the electrical energy storage unit 2.

[0095] As can be seen in [Fig.l], the frequency adaptation stage 30 can comprise exactly two arms, namely:

[0096] - a first arm 31 comprising two capacitors 32 mounted on either side of a first midpoint 33, and

[0097] - a second switching arm 34 comprising two pairs 35 of switches controllable electronics 36a and 36b. In each pair 35, the two switches 36a and 36b are mounted in series, and these two pairs 35 are mounted on either side of a second midpoint 33.

[0098] It can be seen in [Fig.l] that the primary winding 13 of the transformer 11 is here mounted between the two midpoints 33 of the frequency adaptation stage 30. It can also be seen that, in the example described, the secondary inductive cell 20 is mounted in parallel with the two arms 31 and 34 of the frequency adaptation stage 30.

[0099] In the example of [Fig.l]:

[0100] - no physical component is connected in series with the primary winding 13 of the transformer 11 between the two midpoints 33 of the impedance matching stage 30 and, and

[0101] - no physical component is connected in series with the inductive cell secondary, in the parallel branch of the arms of the frequency adaptation stage.

[0102] As will be seen later, the frequency adaptation stage 30 is here controlled so that the frequency of the electric current flowing in the primary winding 13 of the transformer 11 is equal to K times the frequency of the electric current flowing in the secondary inductive cell 20, K being between 5 and 100.

[0103] In the example considered, for each pair 35, the two electronic switches 36a and 36b may have opposite or different doping. These are field effect transistors mounted in common source or common drain. In other examples, they may be bipolar or IGBT transistors mounted in common emitter or common collector.

[0104] For a first pair 35 mounted between a first terminal of the secondary inductive cell 20 and the second midpoint 33, we find:

[0105] - a first controllable switch 36a mounted between the terminal of the first pair 35 connected to the first terminal of the secondary inductive cell 20 and a second controllable switch 36b and,

[0106] - this second controllable switch 36b mounted between the first switch commandable 36a and the second midpoint 33.

[0107] For a second pair 35 mounted between the second midpoint 33 and a second terminal of the secondary inductive cell 20, we find:

[0108] - a first controllable switch 36a mounted between the midpoint 33 and a second controllable switch 36b and,

[0109] - this second controllable switch 36b mounted between the first switch controllable 36a and the terminal of the second pair 35 connected to the second terminal of the secondary inductive cell 20.

[0110] Thus, from one pair 35 to the other, the controllable switches 36a, respectively 36b, have a different positioning relative to the second midpoint 33.

[0111] The first switches 36a may be of the same first doping and the second switches 36b may be of the same second doping opposite to the first doping. The controllable electronic switches 36a and 36b may alternatively all be of the same doping, for example being N-channel MOSFET transistors.

[0112] It can also be seen in [Fig. 1] that, in the example considered, for each controllable electronic switch 36a, 36b of the second arm 34, a diode 37 is mounted in anti-parallel.

[0113] Although not shown, it is also possible that, for each electric switch controllable electronics 36a, 36b of the second arm 34, a capacitor 38 is mounted in parallel.

[0114] 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. In parallel with the two switching arms 24 are mounted, also in parallel with each other, a capacitor 28 and the electrical energy storage unit 2.

[0115] 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.

[0116] The first arm 24 thus comprises two controllable electronic switches 12 and a first midpoint 25 to which a terminal of the secondary winding 14 of the transformer 11 is connected and these two controllable electronic switches 12 are controlled according to a duty cycle a3.

[0117] The second arm 24 thus comprises two controllable electronic switches 12 and a second midpoint 25 to which the other terminal of the secondary winding 14 of the transformer 11 is connected and these two controllable electronic switches 12 are controlled according to a duty cycle a4.

[0118] The primary winding 13 and the secondary winding 14 of the transformer 11 are dimensioned so that the current flowing in the primary winding 13 is equal to 1 / N times the current flowing in the secondary winding 14, N being for example equal to 3.

[0119] In the example of [Fig. 1], the secondary inductive cell 20 is formed by the series association of: an inductor allowing the recovery of the magnetic energy from the primary inductive cell 10, and a capacitor, thus forming a resonant cell. In the example considered, the inductor has a value between ImH and lOOmH and the capacitor has a capacitance between lOOpF and lOOmF. The inductor is for example produced by winding a copper wire, other than Litz wire. As already mentioned, in the case of [Fig.l], the primary inductive cell 10 could also be formed by the series association of: an inductor allowing the generation of magnetic energy, and a capacitor, thus forming a resonant cell.

[0120] In the variant shown in [Fig.2], the secondary inductive cell 20 is formed by an inductance only. No physical capacitor is present, the presence in series of this capacitor with the inductance of the secondary inductive cell 20 being emulated by the control of the switching arms 24 by the primary control unit 3 using the duty cycles a3 and a4. Here again, the inductance is for example produced by winding a copper wire.

[0121] 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.

[0122] 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 winding 14 of the transformer 11.

[0123] RRef has for example a value between 0.1 Q and 20 Q, in particular between 5 Q and 15 'Q. For a given recharging 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 recharging 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.

[0124] 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:

[0125] - 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

[0126] - 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 measured at the output of the secondary inductive cell 20 and according to the voltage at the terminals of the alternating input of the inverter / rectifier 23.

[0127] 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 a duty cycle a4 while the other controllable switch 12 of this arm 24 is controlled according to a duty cycle 1- a4, and a4 is for example determined according to the equation below:

[0128] oc4=(Rref xlll ) / Vbatt

[0129] where Vbatt denotes the voltage across the terminals of the electrical energy storage unit 2.

[0130] Furthermore, the control unit 3 also controls the electronic switches Controllable ironics 36a, 36b of the frequency adaptation stage as follows, when the controllable electronic switches 12 of the inverter / rectifier 23 are controlled as described above:

[0131] - the two controllable electronic switches 36a of the second arm 34 are controlled in PWM with the same duty cycle while the two controllable electronic switches 36b are kept closed during the positive alternation of the voltage at the terminals of the secondary inductive cell 20, and

[0132] - the two controllable electronic switches 36b of the second arm 34 are controlled in PWM with the same duty cycle while the two controllable electronic switches 36a are kept closed during the negative alternation of the voltage at the terminals of the secondary inductive cell 20.

[0133] From one voltage alternation to another, the duty cycle can evolve in the same way over time.

[0134] The invention is not limited to the example which has just been described.

[0135] Although a single control unit 3 is shown, other embodiments are possible, for example the possibility that one control unit is dedicated to controlling the primary sub-circuit 4 and that another control unit is dedicated to controlling the secondary sub-circuit 6.

[0136] Furthermore, other examples than bipolar transistors or field effect transistors are possible for producing the controllable electronic switches of the pairs 35 of the second switching arm 33 of the frequency adaptation stage 30, such as IGBT transistors.

[0137] As already mentioned, the two controllable electronic switches 36a, 36b of the same pair 35 may have the same doping between them, or alternatively, have opposite doping.

Claims

Claims

1. Electrical power supply circuit (1) of an electrical energy storage unit (2), this electrical power supply circuit comprising: - a primary sub-circuit (4), capable of being connected to a voltage network (5), and - a secondary sub-circuit (6), capable of being connected to an electrical energy storage unit (2), the primary sub-circuit (4) and the secondary sub-circuit (6) being configured so as to exchange electrical energy without contact by inductive coupling, the secondary sub-circuit (6) comprising: - a secondary inductive cell (20) for the exchange in contact by inductive coupling of electrical energy with the primary sub-circuit (4), - an inverter / rectifier (23) capable of carrying out an impedance adaptation of the impedance on the alternating input of this inverter / rectifier (23), independently of the impedance of the electrical energy storage unit (2), this inverter / rectifier (23) comprising at less two switching arms (24),each switching arm (24) comprising two electronic switches (12) arranged on either side of a midpoint (25), - a transformer (11), having a primary winding (13), and having at least one secondary winding (14), this secondary winding (14) being mounted between two midpoints (25) of the inverter / rectifier (23), and - a frequency adaptation stage (30), arranged between the secondary inductive cell (20) and the primary winding (13) of the transformer (11), this stage (30) being configured to modify the frequency between the voltage across the terminals of the secondary inductive cell (20) and the voltage across the terminals of the primary winding (13) of the transformer (H).,

2. A circuit according to claim 1, the inverter / rectifier (23) comprising exactly two switching arms (24), and the transformer (11) comprising a single secondary winding (14) mounted between the two midpoints (25) of the inverter / rectifier (23).

3. Circuit according to claim 1 or 2, the frequency adaptation stage (30) comprising two arms (31, 34): a first arm (31) comprising two impedances (32) mounted on either side of a midpoint (33), and - a second switching arm (32) comprising two pairs (35) of controllable electronic switches (36a, 36b) mounted in series, these two pairs (35) being mounted on either side of a midpoint (33), the primary winding (13) of the transformer (11) being mounted between the two midpoints (33) of the frequency adaptation stage (30) and / or the secondary inductive cell (20) being mounted in parallel with the two arms (31, 34) of the frequency adaptation stage (30).

4. Circuit according to claim 3, the impedances (32) of the first arm (31) being capacitors.

5. Circuit according to claim 3 or 4, each pair (35) of controllable electronic switches (36a, 36b) comprising two transistors of opposite doping or of the same doping.

6. Circuit according to claim 5, the two transistors (36a, 36b) of each pair (35) of controllable electronic switches being field effect transistors mounted in common source or common drain, or being bipolar or IGBT transistors and being mounted in common base or common emitter.

7. Circuit according to any one of claims 3 to 6, the frequency adaptation stage (30) comprising, for each controllable electronic switch (36a, 36b), a diode (37) mounted in antiparallel.

8. Circuit according to any one of claims 3 to 7, the frequency adaptation stage (30) comprising, for each controllable electronic switch (36a, 36b), a capacitor (38) connected in parallel.

9. Circuit according to any one of the preceding claims, the secondary inductive cell (20) being constituted by the series association of a capacitor and an inductance.

10. A circuit according to any one of claims 3 to 8, the secondary inductive cell (20) being constituted by an inductance, the switching arms (24) of the inverter / rectifier (23) and the second switching arm (34) of the frequency adaptation stage (30) being controlled so that the voltage across the first arm (31) of the frequency adaptation stage (30) emulates the presence of a capacitor mounted in series with the secondary inductive cell (20).

11. A circuit according to any one of the preceding claims, the inverter / rectifier (23) comprising exactly two switching arms (24), one of these two arms (24) being 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 these two arms (24) being 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 secondary winding (14) of the transformer (11) and the voltage on the alternating input of this inverter / rectifier (23).

12. Circuit according to any one of the preceding claims, the primary sub-circuit (4) comprising: - a primary inductive cell (10) for contactless exchange by inductive coupling of electrical energy with the secondary inductive cell (20), and - an inverter / rectifier (21) comprising at least two switching arms, each switching arm (7) comprising two controllable electronic switches (12) arranged on either side of a midpoint (8).

13. Circuit according to claim 12, the primary inductive cell (10) being constituted by the series association of a capacitor and an inductance.

14. Circuit according to claim 12 or 13, the primary inductive cell (10) being constituted by an inductance, the switching arms (7) of the inverter / rectifier (21) of the primary sub-circuit (6) being controlled so that the voltage across the AC input of this inverter / rectifier (21) emulates the presence of a capacitor connected in series with the primary inductive cell (10).

15. Component for the electrical supply of an electrical energy storage unit (2), comprising the electrical circuit (1) according to any one of the preceding claims, the component defining in particular a structure supporting in a rigidly coupled manner the primary sub-circuit (4) and the secondary sub-circuit (6).

16. Device for supplying electricity to an electrical energy storage unit (2), comprising: - the electrical circuit according to any one of claims 1 to 14, - a charging terminal for a hybrid or electric vehicle, in which the primary sub-circuit (4) of the electrical circuit (1) is arranged or to which the primary sub-circuit (4) is electrically connected, and - a component capable of being embedded in a hybrid or electric vehicle, in which the secondary sub-circuit (6) of the electrical circuit (1) is arranged.

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