Electrical power supply circuit for a vehicle electrical energy storage unit
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-05-31
- Publication Date
- 2026-04-08
AI Technical Summary
Existing contactless power supply circuits for vehicle electrical energy storage units face inefficiencies due to the high cost and size of large passive capacitive and inductive components required for low-frequency operations, which can lead to parasitic behavior affecting energy transfer efficiency.
An electrical circuit with two input terminals, a control unit, and two switching arms that emulate the presence of inductors and capacitors through controlled switching, allowing for impedance adaptation and reducing the need for physical components, thereby simplifying the circuit and improving efficiency.
This solution reduces the size and cost of the power supply circuit while maintaining equivalent electrical behavior, enhancing the efficiency of energy transfer by eliminating the need for expensive and large physical components, and allowing for impedance emulation to match resonant frequencies.
Smart Images
Figure EP2024065125_05122024_PF_FP_ABST
Abstract
Description
[0001] Description
[0002] Title of the invention: 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.
[0006] The solution according to the application filed in France under No. 22 09978 on 09 / 30 / 2022 which is not part of the state of the art consists of applying an alternating voltage to the terminals of a primary inductive cell coupled by inductive coupling to a secondary inductive cell which, by impedance adaptation, makes it possible to transmit electrical energy at low frequency into an electrical energy storage unit, for example an electric vehicle battery. In this solution, it is necessary to adapt the behavior of the inductive cells by installing large passive capacitive and inductive components in order to operate at low frequency. These components are expensive, very large, especially for very low frequencies such as frequencies less than or equal to 1000 Hz, and have an equivalent series resistance ("ESR" in English) whose values can create parasitic behaviors likely to affect the efficiency of the transfer of electrical energy.
[0007] There is a need to provide an electrical circuit that can be integrated into a power supply circuit of a contactless electrical energy storage unit that overcomes the aforementioned drawbacks.
[0008] The invention aims to meet this need and achieves this, according to one of its aspects, using an electrical circuit comprising: two input terminals capable of being connected to a direct voltage,
[0009] - a control unit,
[0010] - a first switching arm, comprising two electronic switches controllable in series on either side of a first midpoint, the switches of this first arm being controlled according to a first cyclic ratio by the control unit,
[0011] - a second switching arm, comprising two electronic switches controllable in series on either side of a second midpoint, the switches of this second arm being controlled according to a second duty cycle by the control unit,
[0012] - an inductive cell for contactless energy exchange constituted by an inductor, being mounted between the first and second midpoints, the first and second arms being mounted in parallel, and the control unit being configured to act on the first and second duty cycles so that the voltage between the first and second midpoints emulates the presence of an inductor and / or a capacitor mounted in series with the inductive cell.
[0013] The invention as defined above makes it possible, by controlling the switching arms, to eliminate a capacitor and / or a physical inductance while obtaining an electrical behavior equivalent to the presence of these physical components. The invention thus takes advantage of the presence of an existing voltage converter to add an additional function to this voltage converter. This reduces the costs and size of the circuit.
[0014] The voltage between the two midpoints thus corresponds to the voltage applied to the series connection:
[0015] - of the inductive cell and an inductance, or
[0016] - the inductive cell and a capacitor, or
[0017] - of the inductive cell, and of an inductance, and of a capacitor.
[0018] The command can emulate an inductor whose value remains constant and / or emulate a capacitor whose capacitance value remains constant.
[0019] The control carried out by the control unit can allow, more broadly than a series connection of an inductance and / or a capacitor, to emulate the presence in series with the inductive cell of a complex impedance, such as an impedance with a negative inductance, an impedance with a capacitor of negative capacitance, or an impedance with an inductance of variable value over time or with a capacitor whose capacitance value varies over time.
[0020] The electrical circuit according to the invention may comprise a current sensor connected in series with the inductive cell. For example, the current sensor is arranged so that the connection between the first and second midpoints of the electrical circuit is constituted by the series connection of the inductive cell and the current sensor. As already indicated, the control carried out by the control unit allows the voltage between this first and second midpoint to also emulate the presence of an inductor and / or a capacitor connected in series with the inductive cell and the current sensor, although this inductor and / or this capacitor are not physically present.
[0021] According to a first variant of the invention, the two input terminals are connected to a voltage network via an AC / DC converter.
[0022] The electrical network provides, for example, a nominal effective voltage of 230V or 110V with a frequency of 50 Hz or 60 Hz. The electrical network is, for example, single-phase.
[0023] 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.
[0024] According to a second variant of the invention, the two input terminals of the electrical circuit are connected to an electrical energy storage unit.
[0025] Typically, 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.
[0026] The invention also relates to an electrical power supply circuit for an electrical energy storage unit, comprising: a first electrical circuit according to the invention, called the “primary circuit”,
[0027] - a second electrical circuit according to the invention, called “secondary circuit”, the control units of the primary circuit and the secondary circuit being configured to act on the first and second duty cycles of each circuit so that:
[0028] - the voltage between the first and second midpoints of the primary circuit emulates the presence of an inductor and / or a capacitor connected in series with the primary inductive cell, and - the voltage between the first and second midpoints of the secondary circuit emulates the presence of an inductor and / or a capacitor connected in series with the secondary inductive cell.
[0029] The two switching arms of the secondary circuit are for example controlled to perform an impedance adaptation, by varying the equivalent impedance between the first and second midpoints of this secondary circuit, independently of the equivalent impedance of the load represented by the electrical energy storage unit. This implementation of impedance adaptation by the two switching arms of the secondary circuit is for example as described in the Applicant's application FR 3 140 490. The content of this application is incorporated by reference into the present application, with regard to the manner of controlling two switching arms between the midpoints of which an inductive cell is mounted to perform the impedance adaptation.
[0030] Advantageously, the invention makes it possible to simplify the electrical power supply circuit:
[0031] - by directly connecting in the primary circuit the inductive cell to the DC / AC converter formed by the two switching arms of the primary circuit and,
[0032] - by directly connecting the inductive cell in the secondary circuit to the impedance adapter formed by the two switching arms of the secondary circuit.
[0033] By adjusting the control laws of the DC / AC converter and the impedance adapter, it is possible to obtain a voltage between the first and second midpoints of the primary circuit, respectively secondary, behaving as if this voltage were applied to an assembly consisting of the primary inductive cell, respectively secondary, in series with an inductance and / or also in series with a capacitor.
[0034] Preferably, the first electrical circuit corresponds to an electrical circuit according to the first variant of the invention and the second electrical circuit corresponds to an electrical circuit according to the second variant of the invention.
[0035] Typically, the electrical power supply circuit according to the invention comprises an electrical energy storage unit mounted between the input terminals of the secondary circuit.
[0036] In order to enable contactless exchange of electrical energy between the primary circuit and the secondary circuit, the inductive cell of the primary circuit and the inductive cell of the secondary circuit are configured to exchange electrical energy contactlessly by inductive coupling. The primary inductive cell may comprise a coil for generating magnetic energy and the secondary inductive cell may comprise in series a coil for recovering magnetic energy from the primary inductive cell.
[0037] Where appropriate, these physical coils and the components whose behavior is emulated are chosen so that the primary inductive cell and the secondary inductive cell have substantially the same resonant frequency.
[0038] Typically, the contactless exchange by inductive coupling of electrical energy takes place at a frequency of less than 10 kHz, for example less than 7 kHz, for example less than 5 kHz, for example less than 3 kHz, or even less than 2 kHz or 1 kHz, in particular still substantially equal to 400 Hz or 50 Hz.
[0039] Alternatively, contactless exchange by inductive coupling of electrical energy can be done at a frequency of 85 kHz.
[0040] In all of the above, the control units can be configured to control the different switching arms so as to selectively achieve:
[0041] - a charge of the electrical energy storage unit from the voltage network, or
[0042] - a load of the voltage network from the electrical energy storage unit.
[0043] Thus, depending on the need, the exchange of electrical energy can take place in one direction or the other.
[0044] 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.
[0045] In all of the above, each control unit can be a digital processing circuit, for example an ASIC (Application-specific integrated circuit) or a microcontroller.
[0046] Alternatively, a single control unit, for example a digital processing circuit, may be provided, this control unit controlling the switching arms of the primary circuit and the secondary circuit.
[0047] Alternatively, the control unit is common to the primary circuit and the secondary circuit, and it comprises a primary circuit control module and a secondary circuit control module.
[0048] 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 circuit and the secondary circuit. Such a component is commonly called an "on-board charger". This component is capable of being embedded in a hybrid or electric vehicle.
[0049] The invention also relates, according to another of its aspects, to a device for supplying electricity to an electrical energy storage unit, comprising:
[0050] - a charging terminal for a hybrid or electric vehicle, in which the primary circuit of the electrical circuit as defined above is arranged or to which is connected, and
[0051] - a component capable of being embedded in a hybrid or electric vehicle, in which the secondary circuit of the electrical circuit as defined above is arranged.
[0052] 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.
[0053] 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:
[0054] [Fig. l] schematically represents an electrical circuit according to a first example of implementation of the invention,
[0055] [Fig.2] schematically represents an electrical circuit comprising the inductive and capacitive components that the present invention makes it possible to emulate.
[0056] 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 power to an electric or hybrid vehicle propulsion system.
[0057] This power supply circuit 1 includes:
[0058] - a primary circuit 4, connected to a voltage network 5, and
[0059] - a secondary circuit 6, connected to the electrical energy storage unit 2.
[0060] The power supply circuit 1 implements a contactless exchange of electrical energy by inductive coupling between the primary circuit 4 and the secondary circuit 6, for charging the electrical energy storage unit 2.
[0061] In the example considered, the primary circuit 4 comprises: two input terminals 13 connected to an AC / DC converter 9 itself connected to a voltage network 5,
[0062] - a primary control unit 7p, - a first switching arm B 1 , comprising two controllable electronic switches 12 in series on either side of a first midpoint 14, the switches of this first arm being controlled according to a first cyclic ratio api by the primary control unit 7p,
[0063] - a second switching arm B2, comprising two controllable electronic switches 12 in series on either side of a second midpoint 15, the switches of this second arm being controlled according to a second duty cycle ap2 by the primary control unit 7p,
[0064] - a primary inductive cell 10 for contactless energy exchange constituted here by an inductance, being mounted between the first 14 and second 15 midpoints.
[0065] As shown in Figure 1, the first B1 and second B2 switching arms are connected in parallel.
[0066] 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 the voltage across the AC / DC converter 9 is also single-phase.
[0067] Each switching arm B1 and B2 of the primary circuit 4 here comprises two controllable electronic switches 12 connected in series, such as MOS, IGBT or bipolar transistors, or thyristors.
[0068] The first arm B1 thus comprises two controllable electronic switches 12 in series between which a first terminal of the primary inductive cell 10 for contactless energy exchange is connected.
[0069] The second arm B2 thus comprises two controllable electronic switches 12 in series between which a first terminal of the primary inductive cell 10 for contactless energy exchange is connected.
[0070] The AC / DC converter 9 is connected in parallel with these two arms B1 and B2.
[0071] According to the embodiment shown in Figure 1, the primary circuit 4 comprises a primary current sensor 8p connected in series with the primary inductive cell 10. This primary current sensor can advantageously send information on the measured current to the primary control unit 7p.
[0072] The primary control unit 7p is here configured to act on the first api and second ap2 duty cycles so that the voltage between the two midpoints 14, 15 of the primary circuit 4 emulates in the example considered the presence of an inductor and a capacitor connected in series with the primary inductive cell 10. The primary inductive cell 10 here comprises a coil allowing the generation of magnetic energy. The control of the duty cycles by the primary control unit 7p makes it possible to emulate the behavior of a capacitor, thus forming a resonant cell. The coil has for example an inductance of between ImH to lOOmH and the capacitor whose behavior is emulated by the control of the duty cycles by the primary control unit has a capacitance of between lOOpF and lOOmF.
[0073] We will now describe an example of secondary circuit 6 with reference to figure 1.
[0074] In the example considered, the secondary circuit 6 comprises:
[0075] - a secondary inductive cell 20 for contactless energy exchange constituted here by an inductance,
[0076] - an AC / DC converter 23 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, and
[0077] - a 7s secondary control unit.
[0078] As shown in Figure 1, the AC / DC converter 23 comprises:
[0079] - a first switching arm B3, comprising two controllable electronic switches 12 in series on either side of a first midpoint 14, the switches of this first arm being controlled according to a first duty cycle asl by the secondary control unit 7s,
[0080] - a second switching arm B4, comprising two controllable electronic switches 12 in series on either side of a second midpoint 15, the switches of this second arm being controlled according to a second duty cycle as2 by the secondary control unit 7s.
[0081] As illustrated in Figure 1, the first B3 and second B4 switching arms are mounted in parallel and the secondary inductive cell 20 is mounted between the two midpoints 14, 15 of the AC / DC converter 23.
[0082] The secondary control unit 7s is configured to act on the first and second duty cycles so that the voltage between the first 14 and the second 15 midpoint of the secondary circuit 6 emulates in the example considered the presence of an inductor and a capacitor mounted in series with the secondary inductive cell 20.
[0083] According to an embodiment shown in Figure 1, the secondary circuit 6 comprises a secondary current sensor 8s mounted in series with the secondary inductive cell 20. This secondary current sensor can advantageously send information on the measured current to the secondary control unit 7s.
[0084] Advantageously, the electrical circuit according to the invention makes it possible to obtain an effect equivalent to the electrical circuit illustrated in Figure 2, this effect being obtained according to the invention in the absence of the capacitors Cp and Cs as well as the inductances Lp2 and Ls2 of Figure 2.
[0085] In the circuit shown in Figure 2, the primary circuit 4 has, between its two midpoints 14 and 15, the series association of a primary impedance Zp and a primary inductive cell Lpl. The primary impedance Zp here comprises in series an inductance Lp2 and a capacitance Cp.
[0086] In the circuit shown in Figure 2, the secondary circuit 6 has between its two midpoints 14 and 15 the series association of a secondary impedance Zs and a secondary inductive cell Lsl. The secondary impedance Zs here comprises in series an inductance Ls2 and a capacitance Cs.
[0087] The coupling between the primary and secondary inductive cells allows for contactless transmission of electrical energy between the primary and secondary circuits. Advantageously, the electrical circuit according to the invention, as for example shown in Figure 1, allows, using the switching arms already present in the circuit according to the prior art, to emulate:
[0088] - the presence of the primary impedance Zp in series with the primary inductive cell 10 on the primary circuit side, and
[0089] - the presence of the secondary impedance Zs in series with the secondary inductive cell 20 on the secondary circuit side, without physically having the components of the primary and secondary impedances.
[0090] As can be seen in Figure 1, the secondary inductive cell 20 here comprises a coil allowing the generation of magnetic energy. The control of the internal duty cycles asl and as2 by the secondary control unit 7s makes it possible to emulate the behavior of a capacitor, thus forming a resonant cell. The coil has for example an inductance of between ImH to lOOmH and the capacitor whose behavior is emulated by the control of the duty cycles by the primary control unit has a capacitance of between lOOpF and lOOmF.
[0091] The AC / DC converter 23 of Figure 1 is for example controlled as follows by the secondary control unit 7s, to carry out the impedance adaptation on the alternating input of this converter 23: -one of the two arms B3 or B4 switches at the frequency of the network 5 and with a duty cycle of 50%, and
[0092] - the other of the two arms B3 or B5 switches at a frequency higher than that of the network 5, for example at least 5 times or 10 times the frequency of the network, 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 at the terminals of the alternating input of the AC / DC converter 23.
[0093] Due to the voltage (apl-ap2)*Vdc, with Vdc the voltage between the two input terminals 13 of the primary circuit, the primary control unit 7p allows to emulate the presence between the first 14 and the second 15 midpoint of the switching arms B1 and B2 of an inductor and a capacitor in series with the primary inductive cell 10.
[0094] Furthermore, with (asl - as2)*Vbatt, with Vbatt the voltage across the electrical energy storage unit 2, it is possible to emulate the presence between the first 14 and second 15 midpoint of the switching arms B3 and B4 of a capacitor and an inductor in series with the secondary inductive cell 20.
[0095] The control of the switching arms B1 and B2, respectively B3 and B4, to emulate a capacitor or an inductor in series with the primary inductive cell 10, respectively secondary 20, consists for example in controlling these switching arms so that the converter of which they are part presents on its alternating input a voltage equal to the product of the instantaneous current measured using the current sensor 8p, respectively 8s, multiplied by the modulus of the desired complex impedance. This control also consists in adding to the aforementioned voltage a time phase shift corresponding to the complex argument of the emulated impedance. If the impedance is a capacitor, the voltage will lag behind the current. If the impedance is an inductor, the voltage will lead the measured current.
[0096] Advantageously, the above solution allows only physical coils to be used in the primary and secondary inductive cells, thereby improving the coupling coefficient of the inductive cell.
[0097] Advantageously, the physical coils in the inductive cells are determined so as to maximize the coupled inductance value since the uncoupled parts of these inductances that can be used in resonance are emulated by the control units of the primary and secondary circuits.
[0098] The invention has been described above with the help of embodiments shown in the figure, without limitation of the general inventive concept. Many other modifications and variations suggest themselves to those skilled in the art, after reflection on the various embodiments illustrated in this application.
[0099] These embodiments are given by way of example and are not intended to limit the scope of the invention, which is determined exclusively by the claims below.
[0100] In the claims, the word "comprising" does not exclude other elements or steps, and the use of the indefinite article "a" or "an" does not exclude a plurality.
[0101] The mere fact that different features are recited in mutually dependent claims does not indicate that a combination of these features cannot be advantageously used. Finally, any reference used in the claims should not be construed as a limitation of the scope of the invention.
Claims
Claims 1. Electrical circuit (4, 6) comprising: two input terminals (13) capable of being connected to a direct voltage, - a control unit (7p, 7s) - a first switching arm (B1, B3), comprising two controllable electronic switches (12) in series on either side of a first midpoint (14), the switches of this first arm being controlled according to a first cyclic ratio by the control unit - a second switching arm (B2, B4), comprising two controllable electronic switches (12) in series on either side of a second midpoint (15), the switches of this second arm being controlled according to a second duty cycle by the control unit, - an inductive cell (10, 20) for the contactless exchange of energy constituted by an inductance, being mounted between the first and second midpoints (14, 15), the first (B1, B3) and second (B2, B4) arms being mounted in parallel, and the control unit (7p, 7s) being configured to act on the first and second duty cycles so that the voltage between the first and second midpoints (14, 15) emulates the presence of an inductance and / or a capacitor mounted in series with the inductive cell (10, 20).
2. Electrical circuit according to the preceding claim in which a current sensor (8p, 8s) is connected in series with the inductive cell (10, 20).
3. Electrical circuit according to claim 2, the assembly between the first (14) and second (15) midpoints being constituted by the series association of the inductive cell and the current sensor.
4. Electrical circuit according to any one of the preceding claims, wherein the two input terminals (13) are connected to a voltage network (5) via an AC / DC converter.
5. Electrical circuit according to one of claims 1 to 3, in which the two input terminals (13) are connected to an electrical energy storage unit (2).
6. Electrical circuit according to claim 5, in which the control unit (7p, 7s) is configured to act on the first and second duty cycles in a manner to carry out an impedance adaptation, by varying the equivalent impedance between the first and second midpoints (14, 15), independently of the equivalent impedance of the load represented by the electrical energy storage unit (2).
7. Electrical circuit according to any one of the preceding claims, wherein the control unit (7p, 7s) is configured to act on the first and second duty cycles so that the capacitance of the emulated capacitor remains constant.
8. Electrical power supply circuit (1) of an electrical energy storage unit (2), comprising: - a first electrical circuit according to any one of claims 1 to 4 or 7, called “primary circuit”, - a second electrical circuit according to one of claims 1 to 3 or 4 to 7, called “secondary circuit”, the control units of the primary circuit and of the secondary circuit being configured to act on the first and second duty cycles of each circuit so that: - the voltage between the first (14) and second (15) midpoints of the primary circuit (4) emulates the presence of an inductor and / or a capacitor connected in series with the inductive cell (10) of the primary circuit (4), and - the voltage between the first (14) and second (15) midpoints of the secondary circuit (6) emulates the presence of an inductor and / or a capacitor connected in series with the inductive cell (20) of the secondary circuit (6).
9. Circuit according to claim 8, comprising an electrical energy storage unit (2) mounted between the input terminals (13) of the secondary circuit (6).
10. Circuit according to claim 8 or 9, the inductive cell (10) of the primary circuit and the inductive cell (20) of the secondary circuit being configured so as to exchange electrical energy without contact by inductive coupling.
11. Circuit according to claim 10, the contactless exchange by inductive coupling of electrical energy taking place at a frequency of less than 10 kHz, in particular less than 7 kHz, in particular less than 5 kHz.
12. Device for supplying electricity to an electrical energy storage unit (2), comprising: - a charging terminal for a hybrid or electric vehicle, in which the primary circuit of the electrical circuit according to any one of claims 8 to 11 is arranged or to which the primary circuit is connected, and - a component capable of being embedded in a hybrid or electric vehicle, in which the secondary circuit of the electrical circuit as claimed in any one of claims 8 to 11 is arranged.