Power supply circuit of a vehicle electrical energy storage unit

Abstract

Secondary sub-circuit (6) for an electrical power supply circuit (1) of an electrical energy storage unit (2), the secondary sub-circuit (6) being capable of contactless exchange by inductive coupling of electrical energy with a primary sub-circuit (4) capable of being connected to a voltage network (5), the secondary sub-circuit (6) being capable of being connected to an electrical energy storage unit (2), the secondary sub-circuit (6) comprising: - a secondary inductive cell (20) capable of contactless exchange by inductive coupling of electrical energy with the primary sub-circuit (4), - a voltage converter (30) capable of performing an impedance adaptation of the impedance on the alternating input of this voltage converter (23), independently of the impedance of the electrical energy storage unit (2),this voltage converter (30) converting the alternating voltage at the terminals of the secondary inductive cell (20) into at least one intermediate voltage (Vint; Vint1, Vint2), and this voltage converter (30) converting the intermediate voltage into a direct output voltage (Vbatt) capable of being connected to the terminals of the electrical energy storage unit (2), the value of this direct output voltage (Vbatt) being lower than that of the intermediate voltage (Vint; Vint1, Vint2). Abstract 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.

[0005] There is a need to provide a power supply to an electrical energy storage unit by contactless transmission which further improves known solutions.

[0006] The invention aims to meet this need and achieves this, according to one of its aspects, using a secondary sub-circuit for an electrical power supply circuit of an electrical energy storage unit, the secondary sub-circuit being capable of contactless exchange by inductive coupling of electrical energy with a sub-circuit primary capable of being connected to a voltage network, the secondary sub-circuit being capable of being connected to an electrical energy storage unit, the secondary sub-circuit comprising:

[0007] - a secondary inductive cell capable of exchanging without contact by inductive coupling electrical energy with the primary sub-circuit,

[0008] - a voltage converter capable of performing an impedance adaptation of the impedance on the AC input of this voltage converter, independently of the impedance of the electrical energy storage unit, this voltage converter converting the AC voltage at the terminals of the secondary inductive cell into at least one intermediate voltage, and this voltage converter converting the intermediate voltage into a DC output voltage capable of being connected to the terminals of the electrical energy storage unit, the value of this DC output voltage being lower than that of the intermediate voltage.

[0009] The above secondary sub-circuit makes it possible to carry out impedance matching when the amplitude of the voltage across the secondary inductive cell is greater than the voltage of the electrical energy storage unit. It is thus possible to charge medium or low voltage electrical energy storage units, without it being necessary for this purpose to increase the number of turns, and therefore the weight and cost, of the primary sub-circuit. This extends in a simple and inexpensive manner the capacity to carry out impedance matching in order to transmit low-frequency electrical energy in an electrical energy storage unit, for electrical energy storage units whose nominal voltage may be 12V, 48V, 60V, or even up to values ​​less than or equal to 200V, or even less than or equal to 300V.

[0010] According to a first exemplary implementation, the voltage converter may comprise an inverter / rectifier comprising at least two switching arms in parallel, each switching arm comprising two electronic switches arranged on either side of a midpoint, and each terminal of the secondary inductive cell is connected to a respective midpoint, the voltage across the arms defining the intermediate voltage, the converter further comprising a voltage step-down converter converting the DC intermediate voltage into the DC output voltage. This voltage step-down converter comprises at least one switching arm comprising two electronic switches arranged on either side of a midpoint. The midpoint of this arm is for example connected via an inductor to an output terminal whose potential difference with ground constitutes the DC output voltage.

[0011] According to this first example, the voltage converter comprises two components connected in cascade, namely the inverter / rectifier and the step-down converter. tension.

[0012] One of the two arms of the inverter / rectifier is for example controlled to switch at the frequency of the electrical energy exchanged without contact by inductive coupling and with a duty cycle of 50%, and the other of the two arms of the inverter / rectifier is then 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 inductive cell and the voltage on the alternating input of this inverter / rectifier. In one example, this duty cycle a is expressed using the following expression:

[0013] oc=(RRef xlll ) / Vint

[0014] where:

[0015] - Vint denotes the intermediate voltage,

[0016] -1 denotes the current flowing in the secondary inductive cell,

[0017] - RRef is the equivalent impedance on the alternating input of the inverter / rectifier, R Ref being equal to the ratio V / I where V is the voltage between the two midpoints of the inverter / rectifier.

[0018] When the two switching arms of the inverter / rectifier are controlled as above, the voltage step-down converter can apply a duty cycle chosen to impose a value of the intermediate voltage higher than that of the output DC voltage. This duty cycle is for example between 2% and 98%.

[0019] Alternatively, the switching arms of the inverter / rectifier are controlled at low frequency to bias the voltage on the AC input of the inverter / rectifier and the switching arm of the voltage step-down converter is controlled to switch at high frequency to impose the value of the intermediate voltage. The intermediate voltage may, according to this alternative, have a rectified sine wave shape.

[0020] The voltage step-down converter is for example a series chopper. Other examples of voltage step-down converters are possible.

[0021] The ratio between the value of the intermediate voltage and the value of the continuous output voltage of the converter can be between 1.5 and 200.

[0022] According to the first example of implementation, the converter may comprise three switching arms, namely: two switching arms for the inverter / rectifier, and one switching arm for the voltage step-down converter. These three switching arms may be connected in parallel, having the intermediate voltage as the common voltage.

[0023] The voltage converter according to this first example of implementation comprises for example only three switching arms. In this case, the voltage converter voltage preferably comprises only six controllable electronic switches, for example MOSFET field effect transistors or IGBT transistors. In a variant in which the converter comprises only six electronic switches, these are not all controllable. The switching arm of the voltage step-down converter comprises, for example, a controllable electronic switch and a non-controllable electronic switch, such as a diode.

[0024] According to a second example of implementation of the invention, the voltage converter comprises:

[0025] - a first input terminal connected to a terminal of the inductive cell secondary,

[0026] - a second input terminal connected to the other terminal of the inductive cell secondary,

[0027] - a first switching arm disposed between the first input terminal and the ground and comprising two electronic switches arranged on either side of a first midpoint,

[0028] - a second switching arm disposed between the second input terminal and the ground and comprising two electronic switches arranged on either side of a second midpoint, and

[0029] - an output terminal arranged between the first and second midpoint,

[0030] two intermediate voltages being defined, each intermediate voltage being defined between an input terminal of the converter and ground, and the output DC voltage being defined between the output terminal and ground.

[0031] According to this second example of implementation, the voltage converter may comprise only two switching arms. The voltage converter is then not formed by cascading two components, unlike the voltage converter according to the first example of implementation. This results in a gain in cost, efficiency, and space requirement for producing the voltage converter.

[0032] Each intermediate voltage is for example a voltage whose variable value remains greater than or equal to the value of the DC output voltage. Each switching arm of the voltage converter is for example controlled so that each intermediate voltage remains positive and always takes a value greater than or equal to the DC output voltage. The control of the switching arms can make it possible to control the values ​​of the intermediate voltages so as to emulate an impedance RRefOn the AC input of the voltage converter.

[0033] According to the second example of implementation:

[0034] - a first capacitor may be mounted between the first input terminal of the converter and ground, and

[0035] - a second capacitor can be mounted between the second input terminal of the converter and ground.

[0036] Each of these two capacitors can maintain the respective intermediate voltage despite the presence of a high-frequency effective current.

[0037] According to this second example of implementation, each electronic switch of the voltage converter can be controllable, such as a field effect transistor of the Mosfet or IGBT type.

[0038] According to the second exemplary implementation, the output terminal can be connected to the first midpoint via a first inductor, and this output terminal can be connected to the second midpoint via a second inductor. These two inductors can both be produced using the same magnetic core on which two separate windings are wound. Alternatively, these two inductors each have their own core. Where appropriate, each inductor is formed by two sub-inductors coupled together.

[0039] When the voltage converter comprises only controllable electronic switches, the two controllable electronic switches of the first arm can be controlled using a first duty cycle a3 and the two controllable electronic switches of the second switching arm can be controlled using a second duty cycle a4, and these two duty cycles are determined as follows:

[0040] a3 = 0.5-X

[0041] [Math.l] a4 = 0.5 + X

[0042] X being a parameter determined as a function of the voltage Vbatt at the terminals of the electrical energy storage unit, of the current I flowing in the secondary inductive cell, and of the equivalent impedance RRef at the terminals of the secondary inductive cell, RRef being equal to the ratio V / I where V is the voltage at the terminals of the secondary inductive cell.

[0043] We can thus emulate a high value for RRef.

[0044] X is for example obtained according to the equation below

[0045] 2xRRefxI

[0046] In all of the above, the secondary inductive cell can be constituted by the series association of a capacitor and an inductance.

[0047] Alternatively, the secondary inductive cell may be constituted by an inductance, two switching arms of the converter, which are the two switching arms of the inverter / rectifier of the converter according to the first example of implementation, 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 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.

[0048] 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.

[0049] The invention can however also be applied if the contactless exchange by inductive coupling of electrical energy takes place at a frequency between 79 kHz and 90 kHz, for example 85 kHz. In this variant, Litz wire is advantageously used to produce the inductance of the secondary inductive cell.

[0050] 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 a value of up to 200V, or even up to 300V. The electrical energy storage unit is used for the electrical propulsion of a vehicle. This vehicle is, for example, a vehicle qualified as a “small mobility vehicle”, for example an electric bicycle, an electric tricycle, an electric scooter or an electric motorcycle. More generally, the invention applies to any form of electric mobility, whether it is a machine rolling on land via four, three, two wheels or any other number of wheels, or a machine moving in the air or on water.

[0051] The invention also relates, according to another of its aspects, to an electrical power supply circuit for an electrical energy storage unit, this electrical power supply circuit comprising:

[0052] - a primary sub-circuit, capable of being connected to a voltage network, and

[0053] - the secondary sub-circuit, connected to the electrical energy storage unit, the secondary sub-circuit being as defined above,

[0054] the primary sub-circuit and the secondary sub-circuit being configured so as to exchange electrical energy without contact by inductive coupling.

[0055] In all that follows, the primary sub-circuit may comprise:

[0056] - a primary inductive cell for contactless exchange by inductive coupling of electrical energy with the secondary inductive cell, and

[0057] - an inverter / rectifier comprising at least two switching arms, each switching arm comprising two electronic switches controllable on either side of a midpoint.

[0058] The secondary inductive cell and the primary inductive cell are advantageously chosen so that they have the same resonance frequency.

[0059] In all of the above, the primary inductive cell may be constituted by the series association of a capacitor and an inductor. Alternatively, 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. 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.

[0060] 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.

[0061] 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 makes it possible to rectify the alternating voltage received from the network when the load is carried out from an alternating voltage network. This other inverter / rectifier can then perform a power factor correction function. Such a correction allows, in a known manner, that the current drawn 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 the energy losses in conduction.

[0062] 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.

[0063] As a further variant, the electrical network can provide a direct voltage.

[0064] 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.

[0065] In all of the above, the control unit may be configured to control the various switching arms so as to selectively perform:

[0066] - a charge of the electrical energy storage unit from the voltage network, Or

[0067] - a load of the voltage network from the electrical energy storage unit.

[0068] Thus, depending on the need, the exchange of electrical energy can be carried out in one direction or the other.

[0069] In all of the above, each controllable electronic switch is, for example, bidirectional.

[0070] 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 sub-circuit or to the secondary sub-circuit.

[0071] The control unit may alternatively comprise a primary sub-circuit control module and a secondary sub-circuit control module.

[0072] Alternatively, each sub-circuit has its own control unit, the latter being able to be a digital processing circuit such as a microcontroller.

[0073] 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 supporting the primary sub-circuit and the secondary sub-circuit in a rigidly coupled manner. Such a component is commonly called an “on-board charger”. This component is capable of being embedded in a hybrid or electric vehicle.

[0074] The invention also relates, according to another of its aspects, to a device for supplying electricity to an electrical energy storage unit, comprising:

[0075] - 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

[0076] - 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.

[0077] 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.

[0078] 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:

[0079] [Fig-1] schematically represents an electrical supply circuit according to a first example of implementation of the invention, and

[0080] [Fig.2] represents the secondary sub-circuit according to a second example of implementation work of the invention.

[0081] [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, or up to 200V. This battery is used to supply an electric or hybrid vehicle propulsion system. The vehicle is, for example, a vehicle described as a “small mobility vehicle”, for example an electric bicycle, an electric tricycle, an electric scooter or an electric motorcycle.

[0082] This electrical power supply circuit 1 comprises:

[0083] - a control unit 3,

[0084] - a primary sub-circuit 4, capable of being connected to a voltage network 5, and

[0085] - a secondary sub-circuit 6, comprising the electrical energy storage unit 2.

[0086] 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.

[0087] The control unit 3 is for example a microcontroller or any digital processing unit.

[0088] In the example considered, the primary sub-circuit 4 comprises:

[0089] - a connector 9 capable of being connected to the electrical network,

[0090] - an inverter / rectifier 21 comprising here two switching arms 7, mounted in parallel and whose operation will be described below, and

[0091] - a primary inductive cell 10 whose operation will be described below.

[0092] 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 of value effective voltage of 120V and frequency of 60Hz, a two-phase voltage of effective value of 208V and frequency of 60Hz or a three-phase voltage of 240V and 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 ensuring for example a power factor correction function.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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 controlled according to a duty cycle a2.

[0097] 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.

[0098] The primary inductive cell 10 can 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 inductance is for example made by winding a copper wire, other than Litz wire.

[0099] In the variant shown in [Fig.l], 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

[0100] We will now describe a first example of implementation of secondary sub-circuit 6 with reference to [Fig.l]. This secondary sub-circuit 6 comprises a cell secondary inductive cell 20 for contactless energy exchange with the primary inductive cell 10, and a voltage converter 30 for generating a direct output voltage Vbatt capable of being connected to the terminals of the electrical energy storage unit 2.

[0101] According to this first example of implementation, the voltage converter 30 comprises in cascade:

[0102] - an inverter / rectifier 23, capable of carrying out an adaptation of the impedance equivalent on its alternating input (therefore on the side of the secondary inductive cell 20), so as to vary this impedance independently of the impedance of the electrical energy storage unit 2, and

[0103] - a voltage step-down converter 31.

[0104] The inverter / rectifier 23 allows, when operating in rectifier mode, to rectify the induced voltage across the terminals of the secondary inductive cell 20 into a direct voltage Vint. 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.

[0105] 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.

[0106] The first arm 24 thus comprises two controllable electronic switches 12 and a first midpoint 25 to which a terminal of the secondary inductive cell 20 is connected and these two controllable electronic switches 12 are controlled according to a duty cycle a3.

[0107] The second arm 24 thus comprises two controllable electronic switches 12 and a second midpoint 25 to which the other terminal of the secondary inductive cell 20 is connected and these two controllable electronic switches 12 are controlled according to a duty cycle a4.

[0108] The secondary inductive cell 20 is for example formed by the series association of: an inductor making it possible to recover 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.

[0109] In the variant shown in [Fig.l], 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 unit of primary control 3 using the duty cycles a3 and a4. Here again, the inductance is for example made by winding a copper wire.

[0110] 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.

[0111] 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 inductive cell 20.

[0112] RRef has for example a value between 0.1 'Q and 20'Q, in particular between 5 'Q and 15 'Q. For a given charging configuration, this configuration being in particular determined by at least one of: the position of the secondary sub-circuit 6 relative to the primary sub-circuit 4 and / or the power level to be transmitted and / or the voltage at the terminals of the electrical energy storage unit 2, RRef can have a fixed value and this value is for example in the aforementioned range. From one charging configuration to another, for example in the case of a greater distance between the primary sub-circuit 4 and the secondary sub-circuit 6 and / or to take into account the aging of the system, the value of RRef can be modified, remaining in particular in the aforementioned range.

[0113] 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:

[0114] - 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

[0115] - the other of the two switching arms 24 switches at a frequency higher than that of the electrical energy exchanged without contact, for example at least 5 times or 10 times this frequency of the electrical energy exchanged without contact, and with a duty cycle a4 modulated according to the alternating current flowing in the secondary inductive cell 20 and according to the voltage across the terminals of the alternating input of the inverter / rectifier 23. One of the controllable switches 12 of the switching arm 24 which switches at a frequency higher than that of the electrical energy exchanged without contact is for example controlled according to the duty cycle a4 while the other controllable switch of this arm 24 is controlled according to the duty cycle 1- a 4, and a4 is for example determined according to the equation below:

[0116] oc4 =(Rref xlll ) / Vint

[0117] where Vint denotes the continuous intermediate voltage across the terminals of the two com- mutation 24.

[0118] It can be seen in [Fig.l] that a capacitor 27 is mounted in parallel with the two switching arms 24. This capacitor 27 is mounted in parallel with a switching arm 33 of the voltage-lowering converter 31. The switching arm 33 here comprises two electronic switches 35 arranged on either side of a midpoint 36. As can be seen in [Fig.l], the midpoint 36 of this arm 33 is here connected via an inductor 37 to an output terminal whose potential difference with ground constitutes the DC output voltage Vbatt. The DC output voltage Vbatt is here applied to a capacitor 39 mounted in parallel with the electrical energy storage unit 2.

[0119] The voltage step-down converter 31 of [Fig.l] is for example controlled as follows by the control unit 3, to lower the voltage Vint to the DC output voltage Vbatt so that Vbatt is equal to a5 times Vint where a3 is between 2 / 3 and 1 / 200:

[0120] - one of the electronic switches 35 of the switching arm 33 is controlled according to the duty cycle a5

[0121] - the other electronic switch 33 is controlled according to the duty cycle l-a5.

[0122] The voltage converter 30 of [Fig.l] thus makes it possible to carry out an adaptation impedance when the induced voltage across the terminals of the secondary inductive cell 20 is greater than the DC output voltage Vbatt.

[0123] According to the first example of implementation, the electronic switches 35 of the switching arm 33 are not necessarily all controllable. In an example not shown but covered by the invention, the step-down converter 31 is a series chopper, and one of the electronic switches 35 of the switching arm 33 is then a diode.

[0124] We will now describe with reference to [Fig. 2] a secondary sub-circuit 6 according to a second example of implementation of the invention, this secondary sub-circuit 6 interacting with a primary sub-circuit 4 which is identical to that described with reference to [Fig. 1] and not shown in [Fig. 2] for reasons of clarity. The secondary sub-circuit 6 of [Fig. 2] is for example always controlled by the control unit 3.

[0125] According to this second example of implementation of the invention, the voltage converter 30 comprises:

[0126] - a first input terminal 40 connected to a terminal of the inductive cell secondary 20,

[0127] - a second input terminal 41 connected to the other terminal of the inductive cell secondary 20,

[0128] - a first switching arm 44 disposed between the first input terminal 40 and the ground and comprising two electronic switches 12 arranged on either side of a first midpoint 45,

[0129] - a second switching arm 44 arranged between the second input terminal 41 and the ground and comprising two electronic switches 12 arranged on either side of a second midpoint 45, and

[0130] - an output terminal 46 arranged between the first and second midpoints 45.

[0131] It can thus be seen that the voltage converter 30 according to this second example of implementation comprises only two switching arms, namely switching arms 44. According to this second implementation example, two intermediate voltages Vintl and Vint2 are defined, Vintl being the voltage across the first switching arm 44 and Vint2 being the voltage across the second switching arm 44.

[0132] The voltage converter 30 according to this second exemplary implementation also comprises two capacitors 48 and 49, each capacitor 48, 49 being mounted in parallel with a respective switching arm 44.

[0133] The output terminal 46 defines with the ground the continuous output voltage Vbatt which is applied to the electrical energy storage unit 2.

[0134] It is also noted in the example considered that the output terminal 46 is connected to each midpoint 45 of a switching arm 44 via an inductance 50, 51. The inductance 50 is thus mounted between the output terminal 46 and the midpoint 45 of the first switching arm 44, and the inductance 51 is mounted between the output terminal 46 and the midpoint 45 of the second switching arm 44. The two inductances 50 and 51 are for example wound on a common core.

[0135] According to this second example of implementation, each electronic switch 12 of a switching arm 44 is controllable. It is for example a field effect transistor such as a Mosfet transistor or an IGBT transistor.

[0136] In the example considered, each intermediate voltage Vintl and Vint2 is a voltage whose variable value remains greater than or equal to the value of the DC output voltage Vbatt. For this purpose, each switching arm 44 of the voltage converter 30 is controlled so that each intermediate voltage Vintl, Vint2 remains positive and always takes a value greater than or equal to the DC output voltage Vbatt.

[0137] This control of the switching arms 44 consists for example of the use for the first switching arm 44 of a first cyclic ratio a3 and the use for the second switching arm of a second cyclic ratio a4, these two cyclic ratios being determined as follows:

[0138] a3 = 0.5-X

[0139] [Math.4] fZ4 — 0.2) + X

[0140] X being a parameter determined as a function of the continuous output voltage Vbatt at the terminals of the electrical energy storage unit 2, of the current I flowing in the secondary inductive cell 20, and of the equivalent impedance RRef at the terminals of the secondary inductive cell 20, RRef being equal to the ratio V / I where V is the voltage at the terminals of the secondary inductive cell 20.

[0141] X is for example obtained according to the equation below

[0143] One of the controllable switches 12 of the first switching arm 44 is for example controlled according to the duty cycle a3 while the other controllable switch of this arm 44 is controlled according to the duty cycle 1- a3.

[0144] One of the controllable switches 12 of the second switching arm 44 is for example controlled according to the duty cycle a4 while the other controllable switch of this arm 44 is controlled according to the duty cycle 1-a4.

Claims

Claims

1. Secondary sub-circuit (6) for an electrical power supply circuit (1) of an electrical energy storage unit (2), the secondary sub-circuit (6) being capable of contactless exchange by inductive coupling of electrical energy with a primary sub-circuit (4) capable of being connected to a voltage network (5), the secondary sub-circuit (6) being capable of being connected to an electrical energy storage unit (2), the secondary sub-circuit (6) comprising: - a secondary inductive cell (20) capable of contactless exchange by inductive coupling of electrical energy with the primary sub-circuit (4), - a voltage converter (30) capable of performing an impedance adaptation of the impedance on the alternating input of this voltage converter (23), independently of the impedance of the electrical energy storage unit (2),this voltage converter (30) converting the alternating voltage at the terminals of the secondary inductive cell (20) into at least one intermediate voltage (Vint; Vinti, Vint2), and this voltage converter (30) converting the intermediate voltage into a direct output voltage (Vbatt) capable of being connected to the terminals of the electrical energy storage unit (2), the value of this direct output voltage (Vbatt) being lower than that of the intermediate voltage (Vint; Vinti, Vint2).,

2. Secondary sub-circuit according to claim 1, the voltage converter (30) comprising an inverter / rectifier (23) comprising at least two switching arms (24) in parallel, each switching arm comprising two electronic switches (12) arranged on either side of a midpoint (25), and each terminal of the secondary inductive cell being connected to a respective midpoint, the voltage across the arms defining the intermediate voltage (Vint), the voltage converter (30) further comprising a step-down converter (31) converting the intermediate voltage (Vint) into the output DC voltage (Vbatt).

3. Secondary sub-circuit according to claim 2, one of two arms of the inverter / rectifier (23) 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 the two arms of the inverter / rectifier (23) 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 circulating in the secondary inductive cell (20) and the voltage on the alternating input of this inverter / rectifier (23).

4. Secondary sub-circuit according to claim 2 or 3, the voltage step-down converter (31) being a series chopper.

5. Secondary sub-circuit according to any one of claims 2 to 4, the ratio between the value of the intermediate voltage (Vint) and the value of the continuous output voltage (Vbatt) of the converter being between 1.5 and 200.

6. A secondary sub-circuit according to any one of claims 2 to 5, the voltage converter (30) comprising exactly three switching arms (24, 33).

7. Secondary sub-circuit according to claim 1, the voltage converter (30) comprising: - a first input terminal (40) connected to one terminal of the secondary inductive cell (20), - a second input terminal (41) connected to the other terminal of the secondary inductive cell (20), - a first switching arm (44) arranged between the first input terminal (40) and ground and comprising two electronic switches (12) arranged on either side of a first midpoint (45), - a second switching arm (44) arranged between the second input terminal (41) and ground and comprising two electronic switches (12) arranged on either side of a second midpoint (45), and - an output terminal (46) arranged between the first and second midpoints (45), two intermediate voltages (Vinti, Vint2) being defined, each intermediate voltage (Vinti, Vint2) being defined between a terminal entry (40,41) of the voltage converter and ground, and the output DC voltage (Vbatt) being defined between the output terminal (46) and ground.,

8. Secondary sub-circuit according to claim 7, each intermediate voltage (Vimi, Vint2) being a voltage whose variable value remains greater than or equal to the value of the continuous output voltage (Vbatt).

9. Secondary sub-circuit according to claim 7 or 8, the output terminal (46) being connected to the first midpoint (45) via a first inductance (50) and this output terminal (46) being connected to the second midpoint (45) via a second inductance (51).

10. Secondary sub-circuit according to any one of claims 7 to 9, the two electronic switches (12) of the first switching arm (44) being controllable and controlled using a first duty cycle a3 and the two electronic switches (12) of the second switching arm (44) being controllable and controlled using a second duty cycle a4, and these two duty cycles being determined as follows rz3 = 0.5-X [Math.7] — 0.5 + XX being a parameter determined as a function of the DC output voltage (Vbatt) at the terminals of the electrical energy storage unit, of the current I flowing in the secondary inductive cell, and of the equivalent impedance RRef at the terminals of the secondary inductive cell, RRef being equal to the ratio V / I where V is the voltage at the terminals of the secondary inductive cell.

11. Secondary sub-circuit according to any one of claims 7 to 10, the voltage converter (30) comprising only two switching arms (24).

12. Secondary sub-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.

13. 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, and - the secondary sub-circuit according to any one of the preceding claims, connected to the 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

14. Device for supplying electricity to an electrical energy storage unit (2), comprising: - the electrical circuit according to claim 13, - 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 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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