Power supply circuit for a vehicle electrical energy storage unit

Abstract

The invention relates to a power supply circuit (1) for an electrical energy storage unit (2), this power supply circuit comprising: - a primary sub-circuit (4), capable of being connected to a voltage network (5); - a secondary sub-circuit (6), capable of being connected to an electrical energy storage unit (2); and - a control unit (3), the primary sub-circuit (4) and the secondary sub-circuit (6) being configured so as to exchange electrical energy contactlessly, via inductive coupling, at the frequency of the alternating voltage at the input of the primary sub-circuit (4), the primary sub-circuit (4) comprising, for each phase of the alternating voltage at its input: - a first switching arm (B1), comprising two controllable electronic switches (12) in series, between which a first terminal of the phase of the network is capable of being connected; - a second switching arm (B2), comprising two controllable electronic switches (12) in series, between which a second terminal of the phase of the network is capable of being connected, and between which a first terminal of a primary inductive cell (10) for contactless energy exchange is connected; and - a third switching arm (B3), comprising two controllable electronic switches (12) in series, between which a second terminal of the primary inductive cell (10) for contactless energy exchange is connected, the first, second, and third arms being connected in parallel.

Description

[0001] Description

[0002] Title of the invention: Electrical power supply circuit for a vehicle electrical energy storage unit

[0003] The present invention relates to a contactless power supply circuit for a vehicle electrical energy storage unit.

[0004] 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

[0005] It is known to electrically power a vehicle electrical energy storage unit by contactless transmission using inductive coupling at a power of between 3 and 50 kW, when the vehicle is stationary or when it is moving. This contactless transmission power supply is then carried out by means of distant electrical sub-circuits that are magnetically coupled and tuned to the same resonant frequency. The magnetically coupled sub-circuits each implement an LC-type resonant cell. However, to transmit a satisfactory power level, in particular several kW, it is necessary to operate at high frequencies, in particular of the order of 85 kHz or more, for the resonant frequency of each resonant sub-circuit. In addition, this type of solution requires operating at a short distance between the two sub-circuits.The frequency and power levels mentioned above, for implementation in kW, may also constitute a danger to the health of people exposed nearby, or a danger to the environment in general.

[0006] US 2020 / 287468 and CN 113 765 358 disclose transformers and do not specify at what frequency the transfer of electrical energy via the transformer's magnetic circuit takes place.

[0007] There is a need to provide a power supply to an electrical energy storage unit by contactless transmission which overcomes the aforementioned drawbacks.

[0008] The invention aims to meet this need and achieves this, according to one of its aspects, using an electrical power supply circuit for an electrical energy storage unit, this electrical power supply circuit comprising:

[0009] - a primary sub-circuit, capable of being connected to a voltage network,

[0010] - a secondary sub-circuit, capable of being connected to an electrical energy storage unit, and

[0011] - a control unit, the primary sub-circuit and the secondary sub-circuit being configured so as to exchange without contact by inductive coupling of electrical energy at the frequency of the alternating voltage at the input of the primary sub-circuit, the primary sub-circuit comprising for each phase of the alternating voltage at its input:

[0012] - a first switching arm, comprising two electronic switches controllable in series, between which a first terminal of the network phase is capable of being connected,

[0013] - a second switching arm, comprising two electronic switches controllable in series, between which a second terminal of the network phase is capable of being connected, and between which a first terminal of a primary inductive cell for contactless energy exchange is connected, and

[0014] - a third switching arm, comprising two electronic switches controllable in series, between which a second terminal of the primary inductive cell for contactless energy exchange is connected, the first, second, and third arms being mounted in parallel, and the control unit being configured to control these first, second, and third switching arms so that:

[0015] - the first and second arms form a first inverter / rectifier, and

[0016] - the second and third arms form a second inverter / rectifier.

[0017] Carrying out a contactless exchange of electrical energy by inductive coupling at the frequency of the alternating voltage at the input of the primary sub-circuit makes it possible to overcome the aforementioned drawbacks in relation to the high frequency levels according to the prior art.

[0018] The creation of two inverter / rectifiers with a common switching arm also makes it possible to reduce the size and costs associated with the primary sub-circuit.

[0019] The electrical network provides, for example, a nominal effective voltage of 230V with a frequency of 50 Hz or 60 Hz. The electrical network is, for example, single-phase.

[0020] The power grid is, for example, a regional or national power grid. Alternatively, it may be an independent local network, for example, comprising one or more batteries powered by energy sources such as wind turbines, solar panels, fuel cells, or hydroelectric generators.

[0021] The control unit is for example configured to control the first and second arms so that the first arm switches at a frequency greater than at least five times, in particular at least ten times, the frequency at which the second arm switches, the second arm switching at the frequency of the alternating voltage at the input of the primary sub-circuit. For the purposes of the present invention, when an arm switches, each of its two controllable electronic switches is opened and closed in a complementary manner with the same switching frequency.

[0022] As already mentioned, the second arm can switch at a frequency less than or equal to 60 Hz, in particular less than or equal to 50 Hz. The first arm can then switch at a frequency greater than 250 Hz, in particular greater than 500 Hz. This switching frequency of the first arm is for example less than 1 MHz, in particular 500 kHz.

[0023] The control unit can be configured to control the second and third arms so that these two arms switch at the same frequency, and so that the third arm is modulated in phase shift relative to the second arm, these two arms switching at the frequency of the alternating voltage at the input of the primary sub-circuit. As already mentioned, the second and third arms can switch at a frequency less than or equal to 60 Hz, in particular less than or equal to 50 Hz. This modulated phase shift makes it possible, for example, to regulate the power transmitted to the secondary sub-circuit.

[0024] The control unit can be configured to control the first and second arms so that these two arms also perform a power factor correction function. Such a correction allows, in a known manner, that the current drawn from the network is as close as possible to a perfect sine wave at the network pulse. This reduces the reactive current and the sub-harmonics which increase energy losses in conduction.

[0025] The primary sub-circuit comprises a primary inductive cell interacting with a secondary inductive cell of the secondary sub-circuit for the contactless exchange of electrical energy by inductive coupling. The primary inductive cell may comprise in series: a coil for generating magnetic energy, and a capacitor, thus forming a resonant cell, and the secondary inductive cell may comprise in series: a coil for recovering the magnetic energy from the primary inductive cell, and a capacitor, thus forming a resonant cell. Where appropriate, these coils and these capacitors are chosen so that the primary inductive cell and the secondary inductive cell have the same resonant frequency.

[0026] The secondary sub-circuit may include:

[0027] - the secondary inductive cell for contactless energy exchange, and

[0028] - a third inverter / rectifier capable of performing an impedance matching of the impedance on the AC input of this third inverter / rectifier, independently of the impedance of the electrical energy storage unit. The impedance on the AC input of the third inverter / rectifier is represented by the ratio V / I where V is the voltage across the secondary inductive cell and I is the intensity of the current flowing through it. The impedance matching thus makes it possible to impose on the AC input of the third inverter / rectifier an impedance independent of that of the electrical energy storage unit, which promotes contactless exchange by inductive coupling of low-frequency electrical energy.

[0029] In one example, the third inverter / rectifier comprises two switching arms connected in parallel, each of these switching arms comprises two controllable electronic switches connected in series, the control unit being configured to control these two arms so that:

[0030] - one of these two arms switches at the frequency of the alternating voltage at the input of the primary sub-circuit and with a duty cycle of 50%, and

[0031] - the other of these two arms switches at a frequency higher than that of said alternating voltage, for example at a frequency higher than at least five times, in particular at least ten times, the frequency of said alternating voltage and with a duty cycle modulated according to the alternating current flowing in the second inductive cell and the voltage on the alternating input of the third inverter / rectifier. This frequency higher than that of the alternating voltage at which this arm of the third inverter / rectifier switches is for example the same as that at which the first arm switches.

[0032] As a further variant, the third inverter / rectifier comprises two switching arms mounted in parallel, each of these switching arms comprises two switches mounted in series, only one switch being controllable among the two switches of an arm, and the control unit being configured to control these two arms so as to carry out the impedance adaptation on the alternating input of this third inverter / rectifier.

[0033] In all of the above, the control unit can be configured to control the different switching arms so as to selectively achieve:

[0034] - a charge of the electrical energy storage unit from the voltage network, or

[0035] - a load of the voltage network from the electrical energy storage unit.

[0036] Thus, depending on the need, the exchange of electrical energy can take place in one direction or the other.

[0037] In all of the above, the electrical energy storage unit may be a lithium-ion battery. This battery has, for example, a nominal voltage of 12V, 48V, 60V or more, for example greater than 300V, for example 400V, 800V or 1000V. In all of the above, 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.

[0038] In all of the above, the control unit can be a digital processing circuit, for example an ASIC (Application-specific integrated circuit) or a microcontroller.

[0039] The control unit may alternatively comprise a primary sub-circuit control module and a secondary sub-circuit control module.

[0040] In all of the above, the first and / or second inductance may be made of metal wire, such as copper. Such metal wire is solid, as opposed to Litz wire. A solid metal wire does not have its cross-section hollowed out. Alternatively, at least one of these inductances, or even each of these inductances, is made of Litz wire.

[0041] The invention also relates, according to another of its aspects, to a component for the electrical power supply of an electrical energy storage unit, comprising the electrical circuit as defined above, the component defining in particular a structure rigidly supporting the primary sub-circuit and the secondary sub-circuit. Such a component is commonly called an “on-board charger”. This component is capable of being embedded in a hybrid or electric vehicle.

[0042] The invention also relates, according to another of its aspects, to a device for supplying electricity to an electrical energy storage unit, comprising:

[0043] - a charging terminal for a hybrid or electric vehicle, in which the primary sub-circuit of the electrical circuit as defined above is arranged, and

[0044] - a component capable of being fitted into a hybrid or electric vehicle, in which the secondary sub-circuit of the electrical circuit as defined above is arranged.

[0045] This terminal then receives electrical energy from an electrical network via a cable which can be a single-phase cable or a three-phase cable. In this case, the primary circuit and the secondary circuit are not integrated into the same physical component.

[0046] The invention may be better understood by reading the following description of a non-limiting example of its implementation and by examining the attached drawing in which:

[0047] [Fig.l] schematically represents an electrical power supply circuit according to an exemplary implementation of the invention, and

[0048] [Fig.2] schematically represents a variant of a third secondary sub-circuit inverter / rectifier. Figure 1 shows a circuit 1 for supplying electricity to an electrical energy storage unit 2. This electrical energy storage unit 2 is, for example, a vehicle battery, which may have a nominal voltage of 48V, 60V, 300V, 400V, 800V or more. This battery is used to supply an electric or hybrid vehicle propulsion system.

[0049] This power supply circuit 1 includes:

[0050] - a control unit 3,

[0051] - a primary sub-circuit 4, capable of being connected to a voltage network 5, and

[0052] - a secondary sub-circuit 6, comprising the electrical energy storage unit 2.

[0053] The power supply circuit 1 implements a contactless exchange of electrical energy by inductive coupling between the primary sub-circuit 3 and the secondary sub-circuit 6, for charging the electrical energy storage unit 2.

[0054] In the example considered, the primary sub-circuit 4 comprises:

[0055] - a connector 9 suitable for connection to the electrical network,

[0056] - three switching arms Bl, B2 and B3, mounted in parallel and whose operation will be described below, and

[0057] - a primary inductive cell 10 whose operation will be described below.

[0058] For example, the electrical network 5 provides a nominal effective voltage of 230V with a frequency of 50 Hz or 60 Hz. The electrical network 5 is single-phase here, so that connector 9 is also single-phase.

[0059] Each arm B1, B2 and B3 of the primary sub-circuit 4 here comprises two controllable electronic switches 12 connected in series, such as MOS, IGBT or bipolar transistors, or thyristors.

[0060] The first arm B1 thus comprises two controllable electronic switches 12 in series between which a first terminal of the network 5 is capable of being connected, here via a smoothing coil.

[0061] The second arm B2 thus comprises two controllable electronic switches 12 in series between which a second terminal of the network 5 is capable of being connected, and between which a first terminal of the primary inductive cell 10 for the contactless exchange of energy is connected.

[0062] The third arm B3 thus comprises two controllable electronic switches 12 in series between which a second terminal of the primary inductive cell 10 for contactless energy exchange is connected.

[0063] The primary inductive cell 10 here comprises in series: a coil allowing the generation of magnetic energy, and a capacitor, thus forming a resonant cell. The coil has for example an inductance of between 1 mH and 100 mH and the capacitor has a capacitance of between 100 pF and 100 mF.

[0064] It can be seen that a capacitor 15 is arranged in parallel with the three switching arms B1 to B3. The latter has, for example, a capacitance between IpF and ImF, for example 1OpF.

[0065] We will now describe a first example of secondary sub-circuit 6 with reference to FIG. 1. This secondary sub-circuit 6 comprises a secondary inductive cell 20 for the exchange of energy without contact with the primary inductive cell 10, and

[0066] - an inverter / rectifier 23, also called “third inverter / rectifier” hereinafter, capable of carrying out an adaptation of the equivalent impedance on its alternating input (therefore on the side of the secondary inductive cell 20), so as to vary this impedance independently of the impedance of the electrical energy storage unit 2.

[0067] As can be seen in Figure 2, the secondary inductive cell 20 here comprises in series: a coil for recovering the magnetic energy from the primary inductive cell 10, and a capacitor 30, thus forming a resonant cell. In the example considered, the coil has an inductance between ImH and lOOmH and the capacitor has a capacitance between lOOpF and lOOmF.

[0068] The inverter / rectifier 23 comprises in the example described two switching arms B4 and B5, each arm comprising two controllable electronic switches 12 in series between which a terminal of the secondary inductive cell 20 for contactless energy exchange is connected.

[0069] The control of the inverter / rectifier 23 allows, for example, the equivalent impedance RR to be varied ef at the terminals of the alternative input, defined between the two midpoints of the arms, independently of the output impedance of this inverter / rectifier 23.

[0070] The equivalent impedance RR e f is represented by the ratio V / I where V is the voltage across the AC input, and I the current intensity on this AC input.

[0071] RRef has for example a value between 5Q and 15'Q. For a given recharging configuration, this configuration being in particular determined by at least one of: the position of the secondary sub-circuit 6 relative to the primary sub-circuit 4 and / or the power level to be transmitted and / or the voltage Vbatt at the terminals of the electrical energy storage unit 2, RR ef may have a fixed value and this value is for example in the aforementioned range. From one charging configuration to another, for example in the event 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 in the aforementioned range. The inverter / rectifier 23 of FIG. 1 is for example controlled as follows by the control unit 3, to carry out the impedance adaptation on the AC input of the third inverter / rectifier 23:

[0072] -one of the two arms B4 or B5 switches at network frequency 5 and with a duty cycle of 50%, and

[0073] - the other of the two arms B5 or B4 switches at a frequency higher than that of the network 5, for example at least 5 times or 10 times the network frequency, and with a duty cycle modulated according to the alternating current measured at the output of the secondary inductive cell 20 and according to the voltage across the alternating input of this third inverter / rectifier 23. One of the controllable switches of the arm B4 or B5 which switches at a frequency higher than that of the power transmitted from the primary sub-circuit 4 is for example controlled according to a duty cycle a while the other controllable switch of this arm B4 or B5 is controlled according to a duty cycle 1- a, and a is for example determined according to the equation below oc=R_(Ref X |I| ) / V_batt

[0074] Alternatively, as shown in Figure 2, the third inverter / rectifier 23 can be implemented differently. The two switching arms B4 and B5 then each comprise two electronic switches in series:

[0075] - a controllable electronic switch 12 between the connection to the secondary inductive cell 20 and the negative terminal of the electrical energy storage unit 2, and

[0076] - a diode 13 between the connection to the secondary inductive cell 20 and the positive terminal of the electrical energy storage unit 2.

[0077] Each connection to the secondary inductive cell 20 of a switching arm B4 or B5 is made via a coil 25 of the secondary inductive cell 20.

[0078] We will now describe how arms B1 to B3 of primary sub-circuit 4 are controlled.

[0079] In the example considered, the control unit 3 is configured to control the first and second arms B1 and B2 so that the first arm B1 switches at a frequency greater than at least five times, in particular at least ten times, the frequency at which the second arm B2 switches, the second arm B2 switching at the frequency of the network 5. The switching frequency at which the first arm B1 switches is for example the same as that at which the arm B4 or B5 switches not switching at the frequency of the network 5.

[0080] As already mentioned, the second arm B2 switches here at network frequency 5, here

[0081] 50Hz or 60Hz. This control of the first and second arms B1 and B2 allows them to form a first inverter / rectifier 21. If necessary, this control of arms B1 and B2 can also allow these two arms B1 and B2 to also perform a power factor correction function. The two arms B1 and B2 form, for example, a “Totem POLE PFC rectifier” or “dual Boost PFC rectifier” assembly known in electronics literature as an assembly.

[0082] In addition to what has just been said, the control unit 3 is here configured to control the second and third arms B2 and B3 so that these two arms switch at the same frequency, which is here that of the network 5, and so that the third arm B3 is modulated in phase shift relative to the second arm B2. This control of the second and third arms B2 and B3 allows the latter to form a second inverter / rectifier 22.

[0083] The invention is not limited to the example just described.

Claims

Claims Electrical power supply circuit (1) for an electrical energy storage unit (2), this electrical power supply circuit comprising: - a primary sub-circuit (4), capable of being connected to a voltage network (5), - a secondary sub-circuit (6), capable of being connected to an electrical energy storage unit (2), and - a control unit (3), the primary sub-circuit (4) and the secondary sub-circuit (6) being configured so as to exchange without contact by inductive coupling of electrical energy at the frequency of the alternating voltage at the input of the primary sub-circuit (4), the primary sub-circuit (4) comprising for each phase of the alternating voltage at its input: - a first switching arm (Bl), comprising two controllable electronic switches (12) in series, between which a first terminal of the network phase is capable of being connected, - a second switching arm (B2), comprising two controllable electronic switches (12) in series, between which a second terminal of the network phase is capable of being connected, and between which a first terminal of a primary inductive cell (10) for contactless energy exchange is connected, and - a third switching arm (B3), comprising two controllable electronic switches (12) in series, between which a second terminal of the primary inductive cell (10) for contactless energy exchange is connected, the first, second, and third arms being mounted in parallel, and the control unit (3) being configured to control these first, second, and third switching arms so that: the first (B1) and second (B2) arms form a first inverter / rectifier (21), and the second and third arms form a second inverter / rectifier (22).Circuit according to claim 1, the control unit (3) being configured to control the first (B1) and second (B2) arms so that the first arm (B1) switches at a frequency greater than at least five times, in particular at least ten times, the frequency at which the second arm (B2) switches, the second arm switching at the frequency of the alternating voltage at the input of the primary sub-circuit (4). Circuit according to claim 2, the second arm (B2) switching at a frequency less than or equal to 60Hz, in particular less than or equal to 50Hz. Circuit according to any one of the preceding claims, the control unit (3) being configured to control the second (B2) and third (B3) arms so that these two arms (B2, B3) switch at the same frequency, and so that the third arm is phase-modulated relative to the second arm, these two arms (B2, B3) switching at the frequency of the alternating voltage at the input of the primary sub-circuit (4). Circuit according to claim 4, the second (B2) and the third (B3) arms switching at a frequency less than or equal to 60 Hz, in particular less than or equal to 50 Hz. Circuit according to any one of the preceding claims, the control unit (3) being configured to control the first (B1) and second (B2) arms so that these two arms also perform a power factor correction function. Circuit according to any one of the preceding claims, the secondary sub-circuit (6) comprising: - a secondary inductive cell (20) for contactless energy exchange, and - a third inverter / rectifier (23) capable of performing an impedance adaptation of the impedance on the alternating input of this third inverter / rectifier (23), independently of the impedance of the electrical energy storage unit (2). Circuit according to claim 7, the third inverter / rectifier (23) comprising two switching arms (B4, B5) mounted in parallel, the control unit (3) being configured to control these two arms (B4, B5) so that: - one of these two arms switches at the frequency of the alternating voltage at the input of the primary sub-circuit (4) and with a duty cycle of 50%, and - the other of these two arms switches at a frequency higher than that of said alternating voltage 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 the third inverter / rectifier (23). Circuit according to any one of the preceding claims, the control unit (3) being configured to control the different switching arms (B1, B2, B3, B4, B5) so as to selectively carry out: - a charge of the electrical energy storage unit (2) from the voltage network (5), or - a load of the voltage network (5) from the electrical energy storage unit (2). Component for the electrical supply of an electrical energy storage unit (2), comprising the electrical circuit (1) according to any one of the claims preceding, the component defining in particular a structure rigidly supporting the primary sub-circuit (4) and the secondary sub-circuit (6) coupled together. Device for the electrical supply of an electrical energy storage unit (2), comprising - a charging terminal for a hybrid or electric vehicle, in which the primary sub-circuit (4) of the electrical circuit (1) according to any one of claims 1 to 9 is arranged, and - a component capable of being embedded in a hybrid or electric vehicle, in which the secondary sub-circuit (6) of the electrical circuit (1) according to any one of claims 1 to 9 is arranged.

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