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,Each switching arm comprises two electronic switches arranged on either side of a midpoint, and a control unit (3) configured to control one of these two arms to switch at the frequency of the electrical energy exchanged without contact by inductive coupling and with a duty cycle of 50%, and to control the other of these two arms 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 (20) and the voltage on the alternating input of this inverter / rectifier (23). Abbreviated figure: Fig. 1,

Description

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

[0001] The present invention relates to a contactless 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 power a vehicle's electrical energy storage unit with a power output between 3 and 50 kW by contactless transmission via inductive coupling, whether the vehicle is stationary or moving. This contactless power supply is achieved using magnetically coupled, distant electrical subcircuits tuned to the same resonant frequency. Each magnetically coupled subcircuit employs an LC-type resonant cell. However, to transmit a satisfactory power level, particularly several kW, it is necessary to operate at high frequencies, specifically on the order of 85 kHz or higher, for the resonant frequency of each resonant subcircuit. Furthermore, this type of solution requires a short distance between the two subcircuits.The frequency and power levels mentioned above, for implementation in kW, can also constitute a danger to the health of people exposed nearby, or a danger to the environment in general.

[0004] The solution according to international application no. PCT / EP2023 / 076297 filed on September 22, 2023, in the name of Valeo Engine Control Systems, which is not part of the published prior art, consists of applying an alternating voltage across the terminals of a primary inductive cell inductively coupled to a secondary inductive cell which, by impedance matching, allows the transmission of low-frequency electrical energy to an electrical energy storage unit, for example, an electric vehicle battery. The impedance matching makes it possible to impose on the AC input of the inverter / rectifier an impedance independent of that of the electrical energy storage unit, which promotes the contactless exchange of low-frequency electrical energy by inductive coupling.

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

[0006] The invention aims to meet this need and it succeeds in doing so, according to one of its

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[0021] aspects, using a power supply circuit for an electrical energy storage unit, this power supply circuit comprising: - a primary sub-circuit, suitable for connection to a voltage network, and - a secondary sub-circuit, suitable for connection to an electrical energy storage unit, the primary and secondary sub-circuits being configured so as to exchange electrical energy without contact by inductive coupling and having a magnetic coupling coefficient k between them the secondary sub-circuit comprising: - a secondary inductive cell for contactless exchange of electrical energy with the primary sub-circuit via inductive coupling, - an inverter / rectifier capable of performing impedance matching of the impedance at the AC 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, and - a control unit configured to control one of these two arms so that it switches at the frequency (Freq) of the electrical energy exchanged without contact by inductive coupling and with a duty cycle of 50%, and to control the other of these two arms so that it switches 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, the secondary inductive cell implementing a secondary capacitor and a secondary inductor, the capacitance of the secondary capacitor being determined as follows >2 Cs = L, x 2 xkx [ I \ J and the value of the secondary inductance being determined as follows T v —__1_____ where Vbatt denotes the nominal voltage value across the terminals of the electrical energy storage unit, P denotes the power with which the contactless exchange of electrical energy by inductive coupling takes place. The value used for k is, for example, a value known approximately, from previous tests, for example. Known to be true, when a first inductor of self-inductance Li and a second inductor of inductance The self-inductances L2 are coupled to each other, k relates these self-inductances and their mutual inductance M by the equation:

[0022] M = kx

[0023] Such values ​​for the capacitance of the secondary capacitor and the secondary inductance make it possible to optimize the exchange of electrical energy by minimizing the current flowing in the secondary inductive cell, and therefore the associated losses.

[0024] The control unit can be configured to control the switching arms of the inverter / rectifier of the secondary sub-circuit so as to impose on the AC input of the inverter / rectifier an equivalent impedance whose value Rref is determined as follows

[0025] Rref=^

[0026] The equivalent impedance is thus adapted to the output impedance of the secondary inductive cell, which makes it possible to maximize efficiency and transmissible power.

[0027] The frequency higher than that of the electrical energy exchanged without contact by inductive coupling is, for example, at least 5 or 10 times the frequency of the electrical energy exchanged without contact. This is, for example, a frequency between 50 kHz and 500 kHz, for example 100 kHz or 150 kHz.

[0028] The control unit is configured, for example, to control:

[0029] - according to a first control mode: a first of these two arms so that it switches at the frequency of the electrical energy exchanged without contact by inductive coupling and with a duty cycle of 50%, and a second of these two arms so that it switches 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, and

[0030] - according to a second control mode: the second arm so that it switches to the frequency of electrical energy exchanged without contact by inductive coupling and with a duty cycle of 50%, and the first arm so that it switches 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.

[0031] Such a control with two control modes makes it possible to avoid using only one arm of the inverter / rectifier to switch at a frequency higher than that of the electrical energy exchanged without contact by inductive coupling. Switching at such a frequency generates greater losses than at the frequency of the electrical energy exchanged without contact by inductive coupling. This avoids, thanks to The invention addresses the fact that the same switching arm experiences high losses and significant temperature increases, which can affect the integrity of the arm's electronic switches. The existence of two control modes prevents the single switching arm from being subjected to high-frequency stress, thus better distributing losses and, consequently, heating across the different switching arms. This allows for a reduction in the temperature of the controllable electronic switches on the various switching arms, improving their performance and integrity. It also eliminates the need for a cooling system for these controllable electronic switches or for sizing them accordingly, thereby improving the compactness and cost of the power supply circuit.

[0032] The control unit can be configured to alternately apply the first control mode and the second control mode.

[0033] The switch from one control mode to another can occur after a predefined time interval. This predefined time interval can be fixed or variable. Each predefined time interval ends, for example, with the current flowing in the secondary inductive cell switching to OA.

[0034] In an example, the duty cycle a is expressed using the following expression:

[0035] °c=(RRef xlll ) / Vbatt

[0036] where:

[0037] -1 designates the current flowing in the secondary inductive cell,

[0038] - RRef is, as already mentioned, the equivalent impedance on the alternative input of the inverter / rectifier, RRef being equal to the ratio V / I where V is the voltage between the two midpoints of the inverter / rectifier,

[0039] In all the foregoing, the secondary inductive cell may be constituted by the series combination of the secondary capacitor and the secondary inductor. Alternatively, the secondary inductive cell may be constituted by a secondary inductor, the switching arms of the inverter / rectifier of the secondary subcircuit being controlled such that the voltage across the AC input of this inverter / rectifier emulates the presence of a secondary capacitor connected in series with the secondary inductive cell. Such control for obtaining 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.

[0040] The secondary inductance includes, for example:

[0041] - an electrical winding other than Litz wire, in particular electrical wire or a winding obtained by stamping at least one metal plate such as copper to define a spiral, and

[0042] - a magnetic core.

[0043] When the electrical winding is obtained by stamping several metal plates, each metal plate can define a spiral layer, and these different layers can be stacked and electrically connected consecutively. The magnetic core is, for example, a plate made of plastoferrite. Any material with a relative magnetic permeability greater than 1 can be suitable for making the magnetic core.

[0044] The contactless exchange of electrical energy by inductive coupling can be carried out at a frequency below 10 kHz, for example below 5 kHz, below 3 kHz, or even below 2 kHz or 1 kHz, notably still substantially equal to 400 Hz or 50 Hz. In this case, and as mentioned above, the secondary inductance of the secondary inductive cell can have its electrical winding made of metallic wire, such as copper, or by stamping at least one metallic plate, such as copper, defining a spiral. Such an electrical conductor is solid, as opposed to Litz wire. A solid electrical conductor does not have a hollow cross-section. Alternatively, the electrical winding of the secondary inductance of the secondary inductive cell is made of Litz wire.

[0045] In all the foregoing, the secondary sub-circuit may include the electrical energy storage unit. The latter may be a lithium-ion type battery. This battery may, for example, have a nominal voltage of 12V, 48V, 60V or more, for example greater than 300V, for example 400V, 800V or 1000V.

[0046] In one embodiment, the inverter / rectifier of the secondary subcircuit can be replaced by the voltage converter disclosed in the application filed by the Applicant in France on February 29, 2024, under number 24 02010. The content of that application is incorporated by reference into the present application. With such a voltage converter, impedance matching can be achieved when the voltage across the secondary inductive cell is greater than the voltage of the electrical energy storage unit. Medium- or low-voltage electrical energy storage units can thus be charged without increasing the number of turns, and therefore the weight and cost, of the primary subcircuit.This allows for a simple and inexpensive extension of the ability to perform impedance matching for the transmission of low-frequency electrical energy in an electrical energy storage unit, for electrical energy storage units with a nominal voltage of 12V, 48V, 60V, or even up to values ​​less than or equal to 200V, or even less than or equal to 300V.

[0047] In all that follows, the primary subcircuit may include:

[0048] - a primary inductive cell for contactless exchange by inductive coupling of electrical energy with the secondary inductive cell, and

[0049] - an inverter / rectifier comprising at least two switching arms, each switching arm comprising two electronic switches controllable on either side of a midpoint.

[0050] The secondary inductive cell and the primary inductive cell are advantageously chosen so that they have the same resonant frequency.

[0051] In all the foregoing, the primary inductive cell may be constituted by the series combination of a primary capacitor and a primary inductor. Alternatively, the primary inductive cell may be constituted by a primary inductor, the switching arms of the inverter / rectifier of the primary subcircuit being controlled such that the voltage across the AC input of this inverter / rectifier emulates the presence of a primary capacitor connected in series with the primary inductive cell. Such control for obtaining 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.

[0052] In the case of a contactless exchange of electrical energy by inductive coupling at a frequency below 10 kHz, particularly below 5 kHz, the primary inductance of the primary inductive cell may have its electrical winding made of metallic wire, such as copper, or by stamping a metallic plate, such as copper. This stamped metal plate may define a spiral. If necessary, several metal plates are stamped, each metal plate defining a spiral layer, and these different layers are stacked and electrically connected consecutively. Such an electrical conductor is solid, as opposed to Litz wire. A solid electrical conductor does not have a hollow cross-section. Alternatively, this electrical winding of the primary inductance of the primary inductive cell is made of Litz wire.

[0053] If necessary, the primary sub-circuit may include another inverter / rectifier mounted upstream of the inverter / rectifier at the midpoints of which the transformer's primary winding is mounted. This other inverter / rectifier rectifies the AC voltage received from the grid when the load is drawn from an AC voltage network. This other inverter / rectifier can then perform a power factor correction function. Such a correction ensures, in a known manner, that the current drawn from the grid is as close as possible to a perfect sine wave at the grid frequency. This reduces reactive current and subharmonics, which increase energy losses during conduction.

[0054] In all the above, the electrical network supplies, 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.

[0055] Alternatively, the electrical network can supply a direct current voltage.

[0056] The control unit can be configured to control the switching arms of the primary sub-circuit and / or the secondary sub-circuit. In the context 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.

[0057] In all the above, the control unit can be configured to control the different switching arms so as to selectively perform:

[0058] - a charge of the electrical energy storage unit from the voltage network, Or

[0059] - a load from the voltage network from the electrical energy storage unit.

[0060] Thus, depending on the need, the exchange of electrical energy can take place in one direction or the other.

[0061] In all the foregoing, each switching arm comprises controllable electronic switches, in particular exclusively electronic switches that 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.

[0062] In all the foregoing, 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 or secondary subcircuit.

[0063] The control unit may alternatively include a primary sub-circuit control module and a secondary sub-circuit control module.

[0064] Alternatively, each sub-circuit has its own control unit, the latter being a digital processing circuit such as a microcontroller.

[0065] The invention also relates, according to another aspect, to a component for the power supply of an electrical energy storage unit, comprising the electrical circuit as defined above, the component defining in particular a A structure rigidly coupled to support the primary and secondary sub-circuits. Such a component is commonly called an "on-board charger." This component is suitable for installation in hybrid or electric vehicles.

[0066] The invention also relates, according to another aspect, to a device for supplying power to an electrical energy storage unit, comprising:

[0067] - a charging station for hybrid or electric vehicles, 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

[0068] - a component suitable for being installed in a hybrid or electric vehicle, in which is arranged the secondary sub-circuit of the electrical circuit as defined above.

[0069] This terminal then receives electrical energy from an electrical network via a cable, which can be a single-phase or three-phase cable. In this case, the primary and secondary circuits are not integrated into the same physical component.

[0070] The invention also relates, according to another aspect, to a secondary inductive cell for a secondary sub-circuit of a power supply circuit of an electrical energy storage unit, such as above, this secondary inductive cell comprising a secondary inductance, this secondary inductance comprising:

[0071] - an electrical winding obtained by stamping at least one metal plate such as copper to define a spiral, and

[0072] - a magnetic core.

[0073] The electrical winding can be obtained by stamping several metal plates, each metal plate can define a spiral layer, and these different layers can be stacked and electrically connected consecutively.

[0074] The electrical winding obtained by stamping at least one metal plate such as copper to define a spiral can alternatively or in combination be used to realize the primary inductance of the primary inductive cell.

[0075] The invention also relates, according to another aspect, to a method for implementing an electrical power supply circuit for an electrical energy storage unit, this electrical power supply circuit comprising:

[0076] - a primary sub-circuit, connected to a voltage network, and

[0077] - a secondary sub-circuit, connected to an electrical energy storage unit,

[0078] the primary sub-circuit and the secondary sub-circuit being configured so as to exchange electrical energy without contact by inductive coupling,

[0079] the secondary sub-circuit comprising:

[0080] - a secondary inductive cell for contactless exchange by inductive coupling

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[0092] of electrical energy with the primary sub-circuit, this secondary inductive cell implementing a secondary capacitor and a secondary inductor, - an inverter / rectifier capable of performing impedance matching of the impedance at the AC 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, and - a control unit configured to control one of these two arms so that it switches at the frequency (Freq) of the electrical energy exchanged without contact by inductive coupling and with a duty cycle of 50%, and to control the other of these two arms so that it switches 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, process in which: - we know: the value of the frequency Fréq, the value of the power P at which the contactless exchange of electrical energy by inductive coupling takes place, the value of the voltage Vbatt across the terminals of the electrical energy storage unit, and the value of the magnetic coupling coefficient k between the primary and secondary sub-circuits, and - The capacitance of the secondary capacitor and the value of the secondary inductance are determined as follows / \2 Cs = Ls x 2 x kx I | \ / [Math.5] T „ 1__built ZxrrxPxF ,eq Everything above still applies to this process. The control unit is, for example, configured to control the switching arms in such a way as to impose on the AC input of the inverter / rectifier an equivalent impedance whose value Rref is determined as follows The invention will be better understood upon reading the following description of a non-limiting example of its implementation and upon examination of the attached drawing in which: [Fig.1] schematically represents an electrical power supply circuit according to an example of implementation of the invention.

[0093] Figure 1 shows a power supply circuit 1 for 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 power a propulsion system of an electric or hybrid vehicle.

[0094] This power supply circuit 1 comprises:

[0095] - a control unit 3,

[0096] - a primary sub-circuit 4, suitable for connection to a voltage network 5, and

[0097] - a secondary sub-circuit 6, comprising the electrical energy storage unit 2.

[0098] The power supply circuit 1 implements a contactless electrical energy exchange by inductive coupling between the primary sub-circuit 4 and the secondary sub-circuit 6, for the charging of the electrical energy storage unit 2, with a coupling coefficient k.

[0099] The control unit 3 is for example a microcontroller or any digital processing unit.

[0100] In the example considered, the primary sub-circuit 4 comprises:

[0101] - a connector 9 suitable for being connected to the electrical network,

[0102] - an inverter / rectifier 21 comprising here two switching arms 7, mounted in parallel, and whose operation will be described below, and

[0103] - a primary inductive cell lO whose operation will be described below.

[0104] The electrical network 5 is represented here in the form of a voltage network The network may be continuous, but alternatively, it may be an alternating voltage network supplying, for example, a nominal RMS voltage of 230V with a frequency of 50 Hz or 60 Hz. Such an alternating voltage network can be single-phase or three-phase. Other voltages are possible, for example, a single-phase RMS voltage of 120V and a frequency of 60 Hz, a two-phase RMS voltage of 208V and a frequency of 60 Hz, or a three-phase voltage of 240V and a frequency of 60 Hz; this list is not exhaustive. If the network supplies alternating voltage, another inverter / rectifier (not shown) is provided between the network and the inverter / rectifier 21. This other inverter / rectifier provides, for example, a power factor correction function.

[0105] 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 of lOpF.

[0106] Each arm 7 of the primary subcircuit 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 ratio cyclic, one in opposition to the other with a dead time by control unit 3.

[0107] 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 ah

[0108] 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.

[0109] 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.

[0110] The primary inductive cell 10 can be formed by the series connection of a primary inductor for generating magnetic energy and a primary capacitor to form a resonant cell. The primary inductor may, for example, have a value between 10H and 10MH, and the primary capacitor may, for example, have a capacitance between 10 nF and 10 mF. The primary inductor may, for example, have its electrical winding made of a copper wire other than Litz wire.

[0111] Alternatively, the primary inductive cell 10 is formed by a primary inductance only. No physical capacitor is present; the presence in series of this primary capacitor with the primary inductance of the primary inductive cell 10 is 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 primary inductance can have its electrical winding made by winding a copper wire.

[0112] We will now describe an example of a secondary subcircuit 6 with reference to [Fig.1]. This secondary subcircuit 6 comprises a secondary inductive cell 20 for the exchange of energy without contact with the primary inductive cell 10, and an inverter / rectifier 23, capable of performing an adaptation of the equivalent impedance on its AC input (i.e. 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.

[0113] The inverter / rectifier 23 in the described example comprises two switching arms 24 arranged in parallel, each arm comprising two controllable electronic switches 12 arranged on either side of a midpoint 25.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] The secondary inductive cell 20 is formed here by the series connection of: a secondary inductor for recovering the magnetic energy from the primary inductive cell 10, and a secondary capacitor, thus forming a resonant cell. The secondary inductor comprises, for example, an electrical winding made by winding a copper wire, other than Litz wire, or by stamping a copper plate to form a spiral winding.

[0118] According to the invention, the value of the secondary inductance is determined using the following equation

[0119] L i vL 2x;txPxFnq

[0120] and the capacitance of the secondary capacitor of the secondary inductive cell 20 is determined using the following equation:

[0121] / „ \2 Cs -L,x2xkx ~~ \ Vh.tt /

[0122] In these equations, Vbatt denotes the value of the nominal voltage across the terminals of the electrical energy storage unit 2 and P denotes the power with which the contactless electrical energy exchange takes place by inductive coupling.

[0123] In the example considered, the inductance has a value between lOOpH and lOmH and the capacitor has a capacitance between lOOnF and lOmF.

[0124] More specifically, considering a power P of 7kW for the contactless electrical energy exchange by inductive coupling and a frequency of 3kHz for this exchange, with a coupling coefficient k of 0.4 and a nominal voltage Vbatt of 400V, the value of 1.356 mH is obtained for the secondary inductance using equation 7. The value of 2.076pF for the capacitance of the secondary capacitor is deduced from equation 8.

[0125] Furthermore, the control unit 3 acts in the described example on the control of the inverter / rectifier 23 so as to impose 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 direct output of this inverter / rectifier 23.

[0126] The equivalent impedance RRef corresponds to the ratio V / I where V is the voltage between the two midpoints 25, and I is the current flowing in the inductive cell se- secondary 20.

[0127] RRef, for example, has a value between 0.1 Q and 40 Q, in particular between 2 Q and 30 Q, in particular between 5 Q and 15 Q. For a given charging configuration, this configuration being determined in particular by at least one of the following: 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 across the terminals of the electrical energy storage unit 2, RRef may have a fixed value, and this value is, for example, within 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 may be modified, remaining in particular within the aforementioned range.

[0128] In the example considered, RRef has a value determined using the following equation:

[0129] Rref = ^

[0130] With the previous values, we obtain for Rref the value of 16.162Q.

[0131] The inverter / rectifier 23 of [Fig. 1] is, for example, controlled as follows by the control unit 3, to perform impedance matching on the AC input of the inverter / rectifier 23:

[0132] - one of the two switching arms 24 switches at the energy frequency electrical current exchanged without contact via inductive coupling and with a duty cycle a3 of 50%, and

[0133] - 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 AC 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- a4, and a4 is for example determined according to the equation below:

[0134] œ4 =(Rref xlll) / Vbatt

[0135] According to an example, this command is executed as follows:

[0136] - according to a first control mode: the first switching arm 24 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 second switching arm 24 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 inductive cell 20 and the voltage on the alternating input of this inverter / rectifier 23, and

[0137] - according to a second control mode: the second switching arm 24 is ordered to switch at the frequency of the electrical energy exchanged without contact by inductive coupling and with a duty cycle of 50%, and the first switching arm 24 is ordered 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.

[0138] The control unit 3 is here configured to alternately apply the first control mode and the second control mode.

[0139] The switch from one control mode to another occurs, for example, after a predefined time interval, which is determined here based on the frequency of the electrical energy exchanged without contact by inductive coupling. This interval is, for example, an integer multiple of the inverse of this frequency. The predefined duration can be on the order of a second.

[0140] It has been observed experimentally that the implementation of the alternation of the above control modes can allow, compared to the initial situation in which only one of the switching arms 24 switches at high frequency, that the temperature of the controllable electronic switches 12 is homogeneous between the two switching arms 24 of the inverter / rectifier 23. A decrease in temperature in °C of more than 25% compared to the temperature of the most "hot" controllable electronic switches 12 according to the initial situation is possible.

[0141] The invention is not limited to the example just described.

[0142] Although a single control unit 3 is shown, other embodiments are possible, for example the possibility that one control unit is dedicated to the control of the primary sub-circuit 4 and another control unit is dedicated to the control of the secondary sub-circuit 6.

Claims

1. Demands Power supply circuit (1) of an electrical energy storage unit (2), this power supply circuit (1) 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 and having a magnetic coupling coefficient k between them, the secondary sub-circuit (6) comprising: - a secondary inductive cell (20) for contactless exchange of electrical energy with the primary sub-circuit (4) by inductive coupling, - an inverter / rectifier (23) capable of performing impedance matching of the impedance at 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 controllable electronic switches (12) arranged on either side of a midpoint (25), and - a control unit (3) configured to control one of these two arms so that it switches at the frequency (Freq) of the electrical energy exchanged without contact by inductive coupling and with a duty cycle of 50%, and to control the other of these two arms so that it switches 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 (20) and the voltage on the alternating input of this inverter / rectifier (23), the secondary inductive cell (20) implementing a secondary capacitor and a secondary inductor, the capacitance of the secondary capacitor being determined as follows Qs = L. x 2 xkx I —r~ I \ vX» / and the value of the secondary inductance being determined as follows T ç — .....L..______ ' yjZxk ^XirxPxFr^ Where Vbatt denotes the value of the nominal voltage across the terminals of the electrical energy storage unit (2), P denotes the power with which the contactless exchange of electrical energy by inductive coupling takes place.

2. Circuit according to claim 1, the control unit (3) being configured to control the switching arms (24) so ​​as to impose on the AC input of the inverter / rectifier (23) an equivalent impedance whose value Rref is determined as follows: Rref = ^

3. Circuit according to claim 1 or 2, the control unit (3) being configured to apply alternately: - a first control mode according to which a first (24) 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 a second (24) 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 inductive cell (20) and the voltage on the alternating input of this inverter / rectifier (23), and - a second control mode according to which the second arm (24) 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 first arm (24) 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 inductive cell (20) and the voltage on the alternating input of this inverter / rectifier (23).

4. Circuit according to any one of the preceding claims, the inverter / rectifier (23) comprising exactly two switching arms (24), the secondary inductive cell (20) being mounted between the two midpoints (25) of this inverter / rectifier.

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

6. Circuit according to claim 5, the secondary inductance comprising: - an electrical winding other than Litz wire, in particular electrical wire or a winding obtained by stamping at least one a metal plate such as copper to define a spiral, and - a magnetic core.

7. Circuit according to any one of the preceding claims, the primary subcircuit (4) comprising: - a primary inductive cell (10) for the 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 (7), each switching arm (7) comprising two controllable electronic switches (12) arranged on either side of a midpoint (8).

8. Component for the power 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 rigidly coupled to each other supporting the primary sub-circuit (4) and the secondary sub-circuit (6).

9. Device for supplying power to an electrical energy storage unit (2), comprising: - the electrical circuit according to any one of claims 1 to 8, - a charging station for a hybrid or electric vehicle, in which the primary sub-circuit (4) of the electrical circuit (1) is disposed or to which the primary sub-circuit (4) is connected, and - a component suitable for being carried in a hybrid or electric vehicle, in which the secondary sub-circuit (6) of the electrical circuit (1) is disposed.

10. A method for implementing a power supply circuit (1) for an electrical energy storage unit (2), said power supply circuit comprising: - a primary sub-circuit (4), connected to a voltage network (5), and - a secondary sub-circuit (6), connected to an electrical energy storage unit (2), the primary sub-circuit (4) and the secondary sub-circuit (6) being configured 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, this secondary inductive cell (20) implementing a secondary capacitor and a secondary inductor, - an inverter / rectifier (23) capable of performing impedance matching of the impedance at 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 comprising two controllable electronic switches (12) arranged on either side of a midpoint, and - a control unit (3) configured to control one of these two arms (24) so ​​that it switches at the frequency (Freq) of the electrical energy exchanged without contact by inductive coupling and with a duty cycle of 50%, and to control the other of these two arms (24) so ​​that it switches 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 (23), method in which: - we know the value of the frequency Fréq, the value of the power P according to which the contactless exchange of electrical energy by inductive coupling takes place, the value of the voltage Vbatt across the terminals of the electrical energy storage unit (2), and the value of the magnetic coupling coefficient k between the primary sub-circuit (4) and the secondary sub-circuit (6), and - The capacitance of the secondary capacitor and the value of the secondary inductance are determined as follows / \2 Cs = L,x2xkx | l5 l V 2 f x ban / [Math. 14] T„ __ 1__^bart " — 2xm <PxF

11. A method according to the preceding claim, wherein the control unit (3) is configured to control the switching arms (24) so ​​as to impose on the alternative input of the inverter / rectifier (23) an equivalent impedance whose value Rref is determined as follows Rre f=^