Electrical power supply circuit of a vehicle electrical energy storage unit
The secondary sub-circuit with phase-shifted switching arms and inductances addresses inefficiencies in contactless power supply systems by enabling efficient power transfer at higher frequencies, reducing switching losses and maintaining current ripple shape.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- VALEO EAUTOMOTIVE GERMANY GMBH
- Filing Date
- 2024-05-07
- Publication Date
- 2026-06-05
Smart Images
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Abstract
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 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. It is therefore desirable to increase the efficiency of such a contactless power supply.
[0004] The invention aims to meet this need and achieves this, according to one of its aspects, by means of a secondary sub-circuit for the electrical power supply of an electrical energy storage unit, this secondary sub-circuit being capable of exchanging electrical energy without contact by inductive coupling with a primary sub-circuit capable of being connected to a voltage network, and this secondary sub-circuit also being capable of being connected to an electrical energy storage unit,
[0005] the secondary sub-circuit comprising:
[0006] - a secondary inductive cell for contactless exchange by inductive coupling of electrical energy with a primary inductive cell of the primary sub-circuit, this secondary inductive cell having a first terminal and a second terminal,
[0007] - an inverter / rectifier capable of performing impedance matching of the impedance on the AC input of this inverter / rectifier, independently of the impedance of the electrical energy storage unit, this inverter / rectifier comprising Ni first switching arms, with Ni greater than or equal to 2, each first switching arm comprising two controllable electronic switches arranged on either side of a midpoint of said first switching arm, each of These first arms, Ni, are capable of being controlled to switch at the same frequency and with a phase shift of 360 / Ni° from one arm to the other.
[0008] the secondary sub-circuit comprising Ni first inductances, each of these Ni first inductances connecting a midpoint of a first switching arm to the first terminal.
[0009] 360 / Ni° thus represents the electrical control angle shift of a first arm to the other.
[0010] The 360 / Ni° phase shift introduced between the first switching arms allows each first inductor to be subjected to an alternating voltage, which produces a current ripple seen by the electronic switches of the first switching arms. Due to this current ripple, the electronic switches of these first switching arms switch to the conducting state to carry a negative current, thereby reducing switching losses.
[0011] 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.
[0012] Thanks to the invention, impedance matching can be achieved by switching the first arms at frequencies higher than that of the electrical energy transmitted without contact by inductive coupling, for example, 5 or 10 times higher than 85 kHz, for example, at a few hundred kHz, without the switching at these high frequencies generating excessive losses. The current ripple advantageously does not affect the shape of the current flowing in the secondary inductive cell, given the value chosen for the first inductances and the resonant frequency of the secondary inductive cell. The advantages of impedance matching are thus benefited by reducing, for a given value of current in the secondary inductive cell, the value of the current flowing in the primary inductive cell, thereby increasing the efficiency of the electrical energy exchange.These advantages remain available, although impedance matching requires the use of high switching frequencies in the first switching arms, since switching losses are significantly reduced.
[0013] Each first inductance has for example the same value between lOOnH and lOpH.
[0014] Ni can be equal to two, three, four or more.
[0015] Each of the first Ni inductances can be dedicated to a respective first arm, so as to connect the midpoint of said arm to the first terminal of the secondary inductive cell. There is thus one first inductance per first switching arm.
[0016] All or part of the first Ni inductances can be magnetically coupled via a single magnetic core. This reduces the number of magnetic components required for the implementation of the first Ni inductances. For example, the first inductances are magnetically coupled in pairs. Alternatively, the first Ni inductances are not coupled to each other, each having its own magnetic core.
[0017] In all the foregoing, the secondary subcircuit may include, in parallel with each controllable electronic switch belonging to a first switching arm, a capacitor. The presence of this capacitor, the value of which is, for example, between 100pF and 100F, makes it possible to reduce the losses during the switching of the corresponding controllable electronic switch to the blocked state.
[0018] In all the above, the secondary inductive cell can be constituted by the series association of a capacitor and an inductor.
[0019] Alternatively, in all the foregoing, the secondary inductive cell may be constituted by an inductor, the switching arms of the inverter / rectifier being controlled such 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 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.
[0020] In all the above, the secondary inductive cell may have a resonance frequency between 79 kHz and 90 kHz, in particular equal to 85 kHz.
[0021] 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.
[0022] According to a first embodiment, the inverter / rectifier comprises a single second switching arm, this second switching arm comprising two controllable electronic switches arranged on either side of a midpoint of said second switching arm which is connected to the second terminal of the secondary inductive cell.
[0023] According to this first embodiment, the first switching arms can be controlled to switch at a frequency higher than that of the electrical energy exchanged without contact by the secondary inductive cell, in particular at a frequency at least 5 or 10 times higher than that frequency The first switching arm can switch at the frequency of the electrical energy exchanged without contact, and the second switching arm can be controlled to switch at the frequency of the electrical energy exchanged without contact by the secondary inductive cell. According to this first implementation example, the first switching arms can switch with a duty cycle modulated by the alternating current flowing through the secondary inductive cell and the voltage at the AC input of the inverter / rectifier, and the second switching arm can switch with a duty cycle of 50%. The impedance at the AC input of the inverter / rectifier of the secondary subcircuit is represented by the ratio V / I, where V is the voltage across the secondary inductive cell and I is the current flowing through it.Impedance matching thus makes it possible to impose, during the charging of the electrical energy storage unit, on the AC input of the inverter / rectifier of the secondary sub-circuit an impedance independent of that of the electrical energy storage unit.
[0024] According to this first embodiment, two, three, or four first arms are provided, for example, and phase-shifted by 180°, 120°, or 90°, and these arms cooperate with a single second switching arm. The first arms switch, for example, at 425 kHz, and the second arm at 85 kHz. When four first arms are present, these first arms are thus phase-shifted by 90°, in pairs.
[0025] A current measurement can be taken for each first arm, and the control of the first arms is then based on these current measurements to balance the average current flowing through each first inductor. Alternatively, a current measurement is taken at the secondary inductive cell and in certain first arms only.
[0026] According to a second embodiment of the invention, the inverter / rectifier may comprise N2 second switching arms with N2 greater than or equal to 2, each second switching arm comprising two controllable electronic switches disposed on either side of a midpoint of said second switching arm, each of these N2 second arms being capable of being controlled so as to switch at the same frequency and with a phase shift of 360 / N2° from one arm to the other,
[0027] the secondary sub-circuit can then comprise N2 second inductances, each of these N2 second inductances connecting a midpoint of a second switching arm to the second terminal of the secondary inductive cell.
[0028] N2 can be equal to two, three, four or more. N2 is, for example, equal to Nb
[0029] A current measurement can be performed for each second arm, and the control of the second arms is then based on these current measurements to balance the average current flowing through each second inductor. Alternatively, a measurement current is generated at the secondary inductive cell and in some second arms only.
[0030] Similar to what was mentioned with reference to the first switching arms, according to this second embodiment, each of the N2 second inductors can be dedicated to a respective second arm so as to connect the midpoint of said arm to the second terminal of the secondary inductive cell. There is thus a second inductor for each second switching arm.
[0031] All or part of the N2 second inductors can be magnetically coupled via a single magnetic core. This reduces the number of magnetic components required for mounting the N2 second inductors. The first inductors are, for example, magnetically coupled in pairs. Alternatively, the N2 second inductors are not coupled to each other, each having its own magnetic core.
[0032] In all the foregoing, the secondary subcircuit may include, in parallel with each controllable electronic switch belonging to a second switching arm, a capacitor. The presence of this capacitor, the value of which is, for example, between 100pF and 100F, makes it possible to reduce the losses during the switching of the controllable electronic switch corresponding to the blocked state.
[0033] According to this second embodiment, the first switching arms and the second switching arms can be controlled to switch at the same frequency higher than that of the electrical energy exchanged without contact by the secondary inductive cell, in particular at a frequency higher than at least 5 times or 10 times this frequency of the electrical energy exchanged without contact.
[0034] More specifically, the first switching arms can be controlled using the same first duty cycle and the second switching arms can be controlled using the same second duty cycle, the first duty cycle being in particular equal to y+x, and the second duty cycle being in particular equal to yx.
[0035] y is a parameter for example between 0 and 0.5 in absolute value, y is for example equal to 0.5.
[0036] In the event that:
[0037] - RRef denotes the equivalent impedance across the terminals of the AC input of the inverter / rectifier,
[0038] - Vbatt designates the nominal voltage across the terminals of the energy storage unit electric, and
[0039] - Pref designates the power at which electrical energy is transmitted, for example 7kW or 11kW,
[0040] x is for example equal to ^batt
[0041] and / or
[0042] y is for example chosen as being greater than and less than 0.5, y being V lease in particular equal to 0.5.
[0043] According to either of the implementation examples, the secondary subcircuit may include at least one of the following:
[0044] - of a capacitor mounted between the first terminal of the secondary inductive cell and the mass,
[0045] - of a capacitor mounted between the second terminal of the secondary inductive cell and the mass, and
[0046] - of a capacitor mounted between the first terminal of the secondary inductive cell and the second terminal of the secondary inductive cell.
[0047] This capacitor or these capacitors allow high-frequency noise to be filtered in the secondary sub-circuit.
[0048] Where applicable, each of the three aforementioned capacitors is simultaneously present in the secondary sub-circuit.
[0049] Each capacitor mounted between a terminal of the secondary inductive cell and ground is, for example, a capacitance X.
[0050] The capacitor mounted between the two terminals of the secondary inductive cell is, for example, a Y-capacitor.
[0051] If applicable:
[0052] - a series assembly of a capacitor and a resistor is connected in parallel with the capacitor connected between the first terminal of the secondary inductive cell and ground, and / or
[0053] - a series assembly of a capacitor and a resistor is connected in parallel of the capacitor mounted between the second terminal of the secondary inductive cell and ground, and / or
[0054] - a series assembly of a capacitor and a resistor is connected in parallel of the capacitor mounted between the first terminal of the secondary inductive cell and the second terminal of the secondary inductive cell.
[0055] The invention also relates, according to another aspect, to a power supply circuit for an electrical energy storage unit, this power supply circuit comprising:
[0056] - a primary sub-circuit, suitable for connection to a voltage network, and
[0057] - the secondary sub-circuit as defined above,
[0058] the primary sub-circuit comprising:
[0059] - a primary inductive cell for contactless exchange by inductive coupling of electrical energy with the secondary inductive cell, and
[0060] - an inverter / rectifier comprising at least two switching arms, each switching arm comprising two controllable electronic switches arranged on either side of a midpoint.
[0061] The secondary inductive cell and the primary inductive cell are advantageously chosen so that they have the same resonance frequency, in particular a resonance frequency between 79 kHz and 90 kHz, for example being on the order of 85 kHz.
[0062] In all the foregoing, 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 subcircuit being controlled in such a way 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.
[0063] If necessary, the primary sub-circuit may include another inverter / rectifier mounted upstream of the inverter / rectifier at the midpoints of which the primary inductive cell is mounted. This other inverter / rectifier rectifies the AC voltage received from the grid when the load is drawn from an AC voltage grid. 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.
[0064] The primary inductive cell can be integrated into a load mat placed in or on the ground, as described in the application filed by the present Applicant on 11 / 09 / 2023 under number 2309545.
[0065] 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.
[0066] Alternatively, the electrical network can supply a direct current voltage.
[0067] The electrical circuit may include a control unit configured to control the switching arms of the primary sub-circuit and / or the secondary sub-circuit.
[0068] In all the above, the control unit can be configured to control the different switching arms so as to selectively perform:
[0069] - a charge of the electrical energy storage unit from the voltage network, Or
[0070] - a load on the voltage network or any other electrical load on the network side from the electrical energy storage unit.
[0071] Thus, depending on the need, the exchange of electrical energy can take place in one direction or the other.
[0072] When the electrical circuit allows a load from the voltage network from the electrical energy storage unit, the inverter / rectifier of the primary sub-circuit may include N3 switching arms with N3 greater than or equal to 2, each switching arm comprising two controllable electronic switches disposed on either side of a midpoint of said switching arm, each of these N3 arms being capable of being controlled during the load from the voltage network or any other electrical load on the network side so as to switch at the same frequency and with a phase shift of 360 / N3° from one arm to the other,
[0073] the primary sub-circuit comprising N3 inductances, each of these N3 inductances connecting a midpoint of one of these switching arms to a terminal of the primary inductive cell.
[0074] N3 is, for example, equal to two, three, four, or more. N3 is, for example, equal to Np
[0075] Similar to what has been described with reference to the secondary sub-circuit, the sub- The primary circuit can:
[0076] - include a single other switching arm, this other switching arm comprising two controllable electronic switches arranged on either side of a midpoint of said other switching arm which is connected to the other terminal of the primary inductive cell, or
[0077] - include N4 other switching arms with N4 greater than or equal to 2, each another switching arm comprising two controllable electronic switches arranged on either side of a midpoint of said other switching arm, each of these N4 other arms being capable of being controlled during the load of the voltage network or any other electrical load on the network side so as to switch at the same frequency and with a phase shift of 360 / N4° from one arm to the other,
[0078] the primary sub-circuit can then comprise N4 inductances, each of these N4 inductances connecting a midpoint of another switching arm to the other terminal of the primary inductive cell.
[0079] N4 can be equal to two, three, four or more. N4 is for example equal to N3.
[0080] Regardless of the number of other switching arms of the inverter / rectifier of the primary sub-circuit, when the non-contact electrical energy transfer by inductive coupling corresponds to a load of the electrical energy storage unit, all arms of this inverter / rectifier can be controlled at the same frequency at which this electrical energy transfer takes place.
[0081] When the contactless electrical energy transfer by inductive coupling corresponds to the load of the electrical network or any other electrical load on the network side, all the first switching arms of the inverter / rectifier of the secondary sub-circuit can be controlled synchronously, and all the second switching arms of this inverter / rectifier can be controlled synchronously with a phase shift between the control of the first arms and that of the second arms. Also during this transfer, the switching arms of the inverter / rectifier of the primary sub-circuit can be controlled so as to switch at the same frequency and with a phase shift of 360 / N3° from one arm to the other and to achieve impedance matching of the impedance at the AC input of this inverter / rectifier, independently of the network impedance or the equivalent impedance of a synchronous rectifier on the network.
[0082] When the inverter / rectifier of the primary subcircuit includes:
[0083] - N3 switching arms, each having its midpoint connected by an inductance to one of the terminals of the primary inductive cell, and
[0084] - N4 switching arms, each having its midpoint connected by an inductance to the other terminal of the primary inductive cell,
[0085] always when the non-contact electrical energy transfer by inductive coupling corresponds to the load of the electrical network or any other electrical load on the network side, the N3 switching arms of the inverter / rectifier of the primary sub-circuit can be controlled so as to switch at the same frequency and with a phase shift of 360 / N3° from one arm to the other, and the N4 switching arms of the inverter / rectifier of the primary sub-circuit can be controlled so as to switch at the same frequency and with a phase shift of 360 / N4° from one arm to the other, and to achieve an impedance matching of the impedance on the AC input of this inverter / rectifier, independently of the network impedance or the equivalent impedance of a synchronous rectifier on the network.
[0086] 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 a bipolar transistor, MOSFET or IGBT, or a thyristor. The MOSFET transistor is, for example, made of SiC. Alternatively, it may be a high electron mobility transistor (HEMT) based on GaN. Each controllable electronic switch is, for example, bidirectional.
[0087] 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.
[0088] The control unit may alternatively include a primary sub-circuit control module and a secondary sub-circuit control module.
[0089] Alternatively, each sub-circuit has its own control unit, which may be a digital processing circuit such as a microcontroller.
[0090] 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 structure rigidly coupled to each other supporting the primary and secondary sub-circuits. Such a component is commonly called an "on-board charger." This component is suitable for installation in a hybrid or electric vehicle.
[0091] The invention also relates, according to another aspect, to a device for supplying power to an electrical energy storage unit, comprising:
[0092] - 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
[0093] - 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.
[0094] 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.
[0095] In all the above, the inductive cell can be configured to exchange with the other inductive cell a power whose value is between 3 kW and 50 kW, for example a power whose value is equal to 7 kW or 11 kW.
[0096] The invention will be better understood upon reading the following description of non-limiting examples of its implementation and upon examination of the accompanying drawing in which:
[0097] [Fig. 1] schematically represents an electrical power supply circuit according to a first example of implementation of the invention,
[0098] [Fig.2] schematically represents a variant of the power supply circuit of [Fig.1],
[0099] [Fig.3] schematically represents a secondary sub-circuit of a power supply circuit according to a second embodiment of the invention, and
[0100] [Fig.4] represents the electrical supply circuit according to the second example of [Fig.3].
[0101] 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.
[0102] This power supply circuit 1 comprises:
[0103] - a control unit 3,
[0104] - a primary sub-circuit 4, suitable for connection to a voltage network 5, and
[0105] - a secondary sub-circuit 6, comprising the electrical energy storage unit 2.
[0106] The 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 the charging of the electrical energy storage unit 2.
[0107] The control unit 3 is for example a microcontroller or any digital processing unit.
[0108] In the example considered, the primary sub-circuit 4 comprises:
[0109] - a connector 9 suitable for being connected to the electrical network,
[0110] - an inverter / rectifier 21 comprising here two switching arms 7, mounted in parallel, and whose operation will be described below, and
[0111] - a primary inductive cell 10 whose operation will be described below.
[0112] The electrical network 5 is represented here in the form of a voltage network continuous, but it can alternatively be an alternating voltage network supplying, 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 RMS value of 120 V and a frequency of 60 Hz, a two-phase voltage with an RMS value of 208 V and a frequency of 60 Hz, or a three-phase voltage of 240 V and a frequency of 60 Hz; this list is not exhaustive. If the grid supplies an alternating voltage, another inverter / rectifier (not shown) is provided between the grid and inverter / rectifier 21. This other inverter / rectifier performs, for example, a power factor correction function.
[0113] 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.
[0114] Each arm 7 of the primary subcircuit 4 here comprises two controllable electronic switches 12, such as MOSFET, 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.
[0115] The first arm 7 thus comprises two controllable electronic switches 12 and a first midpoint 8 to which a first terminal 18 of the primary inductive cell 10 is connected, and these two controllable electronic switches 12 are controlled according to a duty cycle ah
[0116] The second arm 7 thus comprises two controllable electronic switches 12 and a second midpoint 8 to which the second terminal 19 of the primary inductive cell 10 is connected and these two controllable electronic switches 12 are controlled according to a duty cycle a2.
[0117] In the example of [Fig. 1], no physical component is interposed between the two midpoints 8 of the inverter / rectifier 21 and the primary inductive cell 10.
[0118] As can be seen in [Fig. 1], the primary inductive cell 10 can be formed by the series connection of an inductor for generating magnetic energy and a capacitor to form a resonant cell. The inductor may, for example, have a value between 10H and 10MH, and the capacitor may have a capacitance between 10 nF and 1 mF. The inductor may, for example, be made of Litz wire.
[0119] In an unshown embodiment, the primary inductive cell 10 is formed by an inductance only. No physical capacitor is present; the presence of this capacitor in series with the 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 inductance is, for example, made of Litz wire.
[0120] 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.
[0121] The inverter / rectifier 23 in the described example comprises two first switching arms 24a arranged in parallel, each arm here comprising two controllable electronic switches 12 arranged on either side of a midpoint 25a.
[0122] Each first arm 24a thus comprises two controllable electronic switches 12, for example MOSFET transistors, and a first midpoint 25a to which the first terminal 30 of the secondary inductive cell 20 is connected via a first inductance 33. Each first inductance 33 has, for example, the same value between 100H and 10H. One of the controllable electronic switches 12 is controlled here according to a duty cycle α3 while the other is controlled according to a duty cycle 1-α3. The first two inductances 33 may, for example, have a common core, thus being coupled, or they may each have their own core.
[0123] The inverter / rectifier 23 herein further comprises a single second switching arm 24b. This second switching arm also comprises two controllable electronic switches 12, for example MOSFET transistors, and a second center tap 25b to which the second terminal 31 of the secondary inductive cell 20 is connected without the intermediary of an inductor. Similar to the first arms 24a, one of the controllable electronic switches 12 is controlled according to a duty cycle α4, while the other is controlled according to a duty cycle 1-α4.
[0124] The secondary inductive cell 20 is formed here by the series connection of: an inductor for recovering the magnetic energy from the primary inductive cell 10, and a capacitor, thus forming a resonant cell. In the example considered, the inductance has a value between 10H and 10MH and the capacitor has a capacitance between 10 nF and 1 mF.
[0125] In the example considered, each of the primary inductive cell 10 and the secondary inductive cell 20 has the same resonance frequency of 85 kHz, and the contactless exchange of electrical energy by inductive coupling takes place at this resonance frequency and according to a coupling coefficient k.
[0126] The control unit 3 acts in the described example 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 terminals 30, 31 of the secondary inductive cell 20, independently of the impedance on the direct output of this inverter / rectifier 23.
[0127] The equivalent impedance RRef is represented by the ratio V / I where V is the voltage between the two terminals 30, 31, and I is the intensity of the current flowing in the secondary inductive cell 20.
[0128] RRef, for example, has a value between 0.1 'Q and 100 'Q, in particular between 5Q and 30Q. 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.
[0129] The inverter / rectifier 23 of [Fig. 1] is, for example, controlled as follows by the control unit 3, to perform impedance matching at the AC input of the inverter / rectifier 23 during the charging of the electrical energy storage unit 2. The control unit 3 controls the first two arms 24a so that they switch at the same frequency and with a phase shift of 180° from one arm to the other. Each first arm 24a switches, for example, at a frequency of 425 kHz. One of the electronic switches 12 of said arm 24a is thus controlled according to the duty cycle a3 modulated according to: the AC current flowing in the secondary inductive cell 20 and according to the voltage across the AC input of the inverter / rectifier 23. a3 can be calculated according to the equation below:
[0130] œ3 =(Rref xlll) / Vbatt
[0131] where Vbatt designates the voltage across the terminals of the electrical energy storage unit 2.
[0132] The control by the control unit 3 of the first switching arms 24a is done for example by using current measurements taken on each first leg 24a. The control performed on the basis of these measurements makes it possible to balance the average current in each first leg 24a.
[0133] The control unit 3 also here controls the second arm 24b so that it switches at a frequency of 85kHz and with a duty cycle a4 of 50%.
[0134] As can be seen in [Fig. 2], the electrical circuit of [Fig. 1] can be supplemented by the addition of high-frequency noise filtering capacitors. Thus, it can be observed that:
[0135] - a capacitor 40, referred to as "capacitance X", can be mounted between the first terminal 30 of the secondary inductive cell 20 and the ground,
[0136] - a capacitor 40, referred to as "capacitance X", can be mounted between the second terminal 31 of the secondary inductive cell 20 and the ground, and
[0137] - a capacitor 42, referred to as "capacitance Y", can be mounted between the first terminal 30 and the second terminal 31 of the secondary inductive cell 20.
[0138] In the example of [Fig.2], RC damping circuits 41, 43 are mounted in parallel with capacitors 40, 42.
[0139] Circuit 1 of Figures 1 and 2 can allow a load from the electrical grid 5 or any other grid-side electrical load from the electrical energy storage unit 2. In this case, the inverter / rectifier 7 can comprise, similarly to the inverter / rectifier 23:
[0140] - two first switching arms of identical structure to that of the first arms 24a, that is to say, they have their midpoint 8 connected to the first terminal 18 via an inductor, and
[0141] - a single second switching arm of identical structure to that of the second arm 24b, that is to say that it has its midpoint 8 connected to the second terminal 19 without interposed inductance.
[0142] When the contactless electrical energy transfer by inductive coupling corresponds to a load of the electrical energy storage unit 2, all the arms of this inverter / rectifier 7 can be controlled at the same frequency of 85 kHz.
[0143] When the non-contact electrical energy transfer by inductive coupling corresponds to the load of the electrical network 5 or any other electrical load on the network side, all the first switching arms 24a of the inverter / rectifier 23 can be controlled synchronously at the same frequency of 85 kHz, and the switching arms 7 of the inverter / rectifier 8 of the primary subcircuit can be controlled so as to switch at the same frequency and with a phase shift of 180° from one arm to the other, in the example considered, and to achieve an impedance matching of the impedance on the AC input of this inverter / rectifier 21, independently of the network impedance or the equivalent impedance of a synchronous rectification on the network.
[0144] We will now describe, with reference to [Fig.3], a circuit 1 according to a second example of implementation of the invention.
[0145] According to this second embodiment of the invention, the inverter / rectifier 23 of the secondary sub-circuit 6 comprises second switching arms 24b, In the example considered, there are two switching arms, the structure of which is identical to that of the first two switching arms 24a. Each second switching arm 24b thus comprises two controllable electronic switches 12 arranged on either side of a midpoint 25b connected to the second terminal 31 of the secondary inductive cell 20 by a second inductor 34. During the charging of the electrical energy storage unit 5, each second arm 24b is controlled to switch at the same frequency and with a phase shift of 180° from one arm to the other, in the present case where two second arms 24b are provided. The control of the first switching arms 24a by the control unit 3 can be carried out as in the first implementation example, and the control of the second arms 24b is carried out, for example, by using current measurements taken on each second arm 24b.The control performed based on these measurements allows the average current to be balanced in each second arm 24b.
[0146] Figure 3 shows that a 90° offset can exist between the commands of the first arms 24a and those of the second arms 24b. Thus, with respect to the same time reference:
[0147] - the first arms 24a are for example controlled with a phase shift of 0° and 180°, and
[0148] - the second arms 24b are controlled with a phase shift of 90° and 270°.
[0149] Similar to what has been described with reference to the first 33 inductances, The second inductances 34, for example, either share a common core, thus being coupled, or each has its own core. In [Fig. 3], the first inductances 33 are shown as coupled to each other, and the second inductances 34 are also shown as coupled to each other.
[0150] In the example of [Fig. 3], each switching arm of the inverter / rectifier 23, whether it is a first switching arm 24a or a second switching arm 24b, can switch at a frequency of 425 kHz. Given the presence of four arms, the secondary resonant inductive cell 20 perceives an equivalent virtual switching frequency equal to four times, i.e., 1.7 MHz. Such a frequency of 1.7 MHz corresponds to twenty times the resonant frequency of the primary 10 and secondary 20 inductive cells, allowing for satisfactory impedance matching.
[0151] According to this second implementation example:
[0152] - the first switching arms 24a are, for example, controlled using a same first cyclic ratio,
[0153] - the second switching arms 24b are controlled using the same second cyclical report, and
[0154] - the first duty cycle is here equal to y+x, and the second duty cycle is equal to yx. y is for example a parameter between 0 and 0.5 in absolute value, y is for example equal to 0.5.
[0155] In a particular case, with RRef denoting the equivalent impedance across the terminals of the AC input of the inverter / rectifier, Vbatt denoting the nominal voltage across the terminals of the electrical energy storage unit, and Pref denoting the power at which the electrical energy is transmitted, for example 7kW or 11kW,
[0156] y is for example greater than or equal to JSpST and less than or equal to 0.5, and beat
[0157] x can be equal to .
[0158] Similar to what was described with reference to the first implementation example, circuit 1 of [Fig. 3] can allow a load from the electrical grid 5 or any other grid-side electrical load from the electrical energy storage unit 2. In this case, and as shown in [Fig. 4], the inverter / rectifier 7 can comprise, similarly to the inverter / rectifier 23:
[0159] - two first switching arms of identical structure to that of the first arm 24a, that is to say, they have their midpoint 8 connected to the first terminal 18 via a first inductor, and
[0160] - two second switching arms of identical structure to the second arm 24b, that is to say that they have their midpoint 8 connected to the second terminal 19 via a second inductance.
[0161] According to this second example of implementation also, capacitors 40, 41, and their RC damping circuits 42, 43 can also be provided, similarly to what has been described with reference to [Fig.2].
[0162] The invention is not limited to the example just described. In particular, 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 another control unit is dedicated to controlling the secondary sub-circuit 6.
[0163] Furthermore, although not shown in the figures, a capacitor (in the form of a physical and non-parasitic component) may be present in parallel with each controllable electronic switch 12.
Claims
Demands
1. Secondary sub-circuit (6) for supplying power to an electrical energy storage unit (2), said secondary sub-circuit (6) being capable of exchanging electrical energy without contact by inductive coupling with a primary sub-circuit (4) capable of being connected to a voltage network (5), and said sub-circuit (6) also being capable of being connected to an electrical energy storage unit (2), the secondary sub-circuit (6) comprising: - a secondary inductive cell (20) for the exchange of electrical energy with the primary sub-circuit (4) by inductive coupling, said secondary inductive cell (20) having a first terminal (30) and a second terminal (31), - an inverter / rectifier (23) capable of performing impedance matching of the impedance on the AC input of said inverter / rectifier (23), independently of the impedance of the electrical energy storage unit (2),this inverter / rectifier (23) comprising Ni first switching arms (24a), with Ni greater than or equal to 2, each first switching arm (24a) comprising two controllable electronic switches (12) disposed on either side of a midpoint (25a) of said first switching arm (24a), each of these Ni first arms (24a) being capable of being controlled so as to switch at the same frequency and with a phase shift of 360 / Ni° from one arm to the other, the secondary sub-circuit (6) comprising Ni first inductances (33), each of these Ni first inductances (33) connecting a midpoint (25a) of a first switching arm (24a) to the first terminal (30) of the secondary inductive cell (20).
2. Secondary sub-circuit according to claim 1, each of the first Ni inductances (33) being dedicated to a respective arm (24a) so as to connect the midpoint (25a) of said arm to the first terminal (30) of the secondary inductive cell (20).
3. Secondary subcircuit according to claim 1 or 2, all or part of the first Ni inductances (33) being magnetically coupled through a single magnetic core.
4. Secondary subcircuit according to any one of the preceding claims, the inverter / rectifier (23) comprising a single second switching arm (24b), this second arm of switching (24b) comprising two controllable electronic switches (12) arranged on either side of a midpoint (25b) of said second switching arm (24b) which is connected to the second terminal (31) of the secondary inductive cell (20).
5. Secondary subcircuit according to claim 4, the first switching arms (24a) being controlled to switch at the same frequency higher than that of the electrical energy exchanged without contact by the secondary inductive cell (20), in particular at a frequency higher than at least 5 times or 10 times that frequency of the electrical energy exchanged without contact, and the second switching arm (24b) being controlled to switch at the frequency of the electrical energy exchanged without contact by the secondary inductive cell (20).
6. Secondary subcircuit according to any one of claims 1 to 3, the inverter / rectifier (23) comprising N2 second switching arms (24b) with N2 greater than or equal to 2, each second switching arm (24b) comprising two controllable electronic switches (12) disposed on either side of a midpoint (25b) of said second switching arm, each of these N2 second arms (24b) being capable of being controlled so as to switch at the same frequency and with a phase shift of 360 / N2° from one arm to the other, the secondary subcircuit comprising N2 second inductors (34), each of these N2 second inductors (34) connecting a midpoint (25b) of a second switching arm (24b) to the second terminal (31) of the secondary inductive cell (20).
7. Secondary subcircuit according to the preceding claim, the first switching arms (24a) and the second switching arms (24b) being controlled to switch at the same frequency higher than that of the electrical energy exchanged without contact by the secondary inductive cell (20), in particular at a frequency higher than at least 5 times or 10 times that frequency of the electrical energy exchanged without contact.
8. Secondary subcircuit according to the preceding claim, the first switching arms (24a) being controlled using the same first duty cycle and the second switching arms (24b) being controlled using the same second duty cycle, the first duty cycle being in particular equal to y+x, and the second duty cycle being in particular equal to yx, y being between 0 and 0.5, being in particular equal to 0.5, and x being in particular equal to , where RRef denotes the equivalent impedance across the terminals of the AC input of the inverter / rectifier (23), and Vbatt denotes the nominal voltage across the terminals of the electrical energy storage unit (2).
9. Secondary subcircuit according to any one of the preceding claims, comprising at least one of: - a capacitor (40) between the first terminal (30) of the secondary inductive cell and ground, - a capacitor (40) between the second terminal (31) of the secondary inductive cell and ground, and - a capacitor (42) between the first terminal (30) of the secondary inductive cell (20) and the second terminal (31) of the secondary inductive cell (20).
10. Secondary subcircuit according to any one of the preceding claims, the secondary inductive cell (20) being constituted by the series association of a capacitor and an inductor.
11. Secondary subcircuit according to any one of the preceding claims, the secondary inductive cell (20) having a resonant frequency between 79 kHz and 90 kHz, in particular being equal to 85 kHz.
12. Power supply circuit (1) of an electrical energy storage unit (2), said power supply circuit comprising: - a primary sub-circuit (4), suitable for connection to a voltage network (5), and - the secondary sub-circuit (6) 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 (7), each switching arm (7) comprising two controllable electronic switches (12) arranged on either side of a midpoint (15).
13. Power supply circuit according to claim 12, the inverter / rectifier (21) of the primary subcircuit comprising N3 switching arms (7) with N3 greater than or equal to 2, each switching arm (7) comprising two controllable electronic switches disposed on either side of a midpoint of said switching arm, each of these N3 arms being capable of being controlled so as to switch at the same frequency and with a phase shift of 360 / N3° from one arm to the other, the primary subcircuit (4) comprising N3 inductors, each of these N3 inductors connecting a midpoint of a switching arm (7) to a terminal (18, 19) of the primary inductive cell (10).
14. Component for the power supply of an electrical energy storage unit (2), comprising the electrical circuit (1) according to claim 12 or 13, the component defining in particular a structure rigidly coupled to each other supporting the primary sub-circuit (4) and the secondary sub-circuit (6).
15. Device for supplying power to an electrical energy storage unit (2), comprising: - the electrical circuit according to claim 12 or 13, - 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 electrically 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.