Method for managing a high-voltage electrical circuit of a motor vehicle

Abstract

The invention relates to a managing method, comprising: - a high-voltage electrical source (1), having a positive pole and a negative pole, - a branch (2) of the high-voltage electrical circuit supplying at least one high-voltage component, a first end (21) of the branch being connected to the positive pole via a first contactor (4) and a second end (22) of the branch being connected to the negative pole via a second contactor (5), the first and second contactors (4, 5) being independently controllable to open or close, the method comprising increasing a voltage between the first end and second end, and selecting the given contactor, this comprising execution of logic to alternate between the first and second contactor so as to increase a lifetime of an assembly consisting of the first and second contactors.

Description

Description Title of the invention: Method for managing a high-voltage electrical circuit of a motor vehicle.

[0001] The invention relates to a method for managing a high-voltage electrical circuit in a motor vehicle. The invention also relates to a system for managing a high-voltage electrical circuit in a motor vehicle. Furthermore, the invention relates to a motor vehicle equipped with a high-voltage electrical circuit management system.

[0002] The traction electrical system of a fully electric or hybrid vehicle must isolate the traction battery from two types of components: those that generate energy to charge the battery and those that consume energy. Specifically, the traction battery is isolated when the vehicle is not in use.

[0003] During driving phases where the vehicle's traction electrical system needs to be re-energized by the traction battery, the vehicle's traction electrical network must be reconnected to the traction battery. Reconnecting the battery to the vehicle's traction electrical network requires minimizing the voltage difference between the voltage at the traction battery terminals and the voltage at the vehicle's traction electrical network terminals. One solution involves pre-charging the vehicle's electrical network upstream of the connection between the battery and the vehicle's traction electrical network. However, while this solution helps limit the voltage difference between the electrical network at the traction battery terminals and the voltage at the vehicle's traction electrical network terminals, it does have drawbacks.Indeed, even a small, persistent voltage difference can generate an electric arc at a circuit closure point when the electrical circuit is closed. Such a current spike can damage the circuit closure point, particularly due to the repetition of this phenomenon.

[0004] The technical solutions currently implemented to close or open an electrical traction circuit have drawbacks.

[0005] The object of the invention is to provide a method for managing a high-voltage electrical circuit that overcomes the above drawbacks and improves upon prior art methods for managing a high-voltage electrical circuit. In particular, the invention enables the implementation of a method for managing an electrical circuit high voltage which is reliable and efficient and which improves the service life of the means of opening and closing a high voltage electrical circuit.

[0006] To this end, the invention relates to a method for managing a high-voltage electrical circuit in a motor vehicle, the high-voltage electrical circuit comprising: - a high-voltage electrical source, having a positive pole and a negative pole, - a given branch of the high-voltage electrical circuit supplying at least one high-voltage component, in particular the given branch supplying an electrical traction network of the motor vehicle, a first end of the given branch being connected to the positive pole of the electrical source via a first contactor, and a second end of the given branch being connected to the negative pole of the electrical source via a second contactor, the first and second contactors being independently controllable for their opening and closing.

[0007] Furthermore, the process includes increasing the voltage between the first and second ends of the given branch, followed by closing the high-voltage electrical circuit, comprising: - a selection of a given contactor taken from either the first or second contactor, then - a command to close the given contactor, then - a contactor closing command other than the given contactor. Furthermore, the selection of the given contactor includes an implementation of alternating logic between the first and second contactors in order to increase the lifespan of an assembly consisting of the first and second contactors.

[0008] In one embodiment, the alternation logic includes a systematic alternation of a selection between the first and second contactor.

[0009] In one embodiment, the alternating logic takes into account a wear rate of the first and second contactor, the given contactor being determined as the contactor with the highest wear rate.

[0010] In one embodiment, the increase in voltage between the first end and the second end of the given branch is controlled so as to minimize a difference between a first voltage, measured across the terminals of the high-voltage power source, and a second voltage measured between the first end and the second end of the given branch.

[0011] In one embodiment, the high-voltage circuit further includes a DC-current converter powered by a low-voltage battery, and the voltage increase between the first and second ends of the given branch is implemented by the current converter capable of generating a high voltage direct current between the first end and the second end of the given branch from a direct current supplied by the low voltage battery.

[0012] The invention further relates to a device for managing a high-voltage electrical circuit of a motor vehicle, the device comprising hardware and / or software elements configured to implement the method according to the invention.

[0013] The invention also relates to a motor vehicle comprising a device for managing a high-voltage electrical circuit according to the invention.

[0014] The invention also relates to a computer program product comprising program code instructions recorded on a computer-readable medium to implement the steps of the process according to the invention when said program is running on a computer or a computer program product downloadable from a communication network and / or recorded on a computer-readable and / or computer-executable data medium, comprising instructions which, when the program is executed by the computer, cause the computer to implement the process according to the invention.

[0015] The invention also relates to a computer-readable data recording medium on which is recorded a computer program comprising program code instructions for implementing the process according to the invention, or a computer-readable recording medium comprising instructions which, when executed by a computer, lead the computer to implement the process according to the invention.

[0016] The invention also relates to a signal from a data carrier, carrying the computer program product according to the invention.

[0017] Figure 1 schematically represents a motor vehicle equipped with a high-voltage electrical circuit management system according to an embodiment of the invention.

[0018] Figure [Fig. 2] is a flowchart of a method for managing an electrical circuit according to the invention.

[0019] Figure [Fig. 3] illustrates a temporal sequence of the closure of a high-voltage electrical circuit.

[0020] An embodiment of a motor vehicle 100 according to the invention is described below with reference to figures 1 to 3. The motor vehicle 100 is a motor vehicle of any type, in particular a passenger vehicle or a utility vehicle.

[0021] In one embodiment more specifically described in this document, the motor vehicle 100 is an electric vehicle comprising a high-voltage electrical circuit 10 comprising - a high-voltage electrical source 1, having a positive pole 11 and a negative pole 12, - a given branch 2 of the circuit supplying at least one high-voltage component 3, in particular the given branch 2 supplying an electrical traction network 3 of the vehicle, a first end 21 of the given branch 2 being connected to the positive pole 11 of the electrical source via a first contactor 4, and a second end 22 of the given branch 2 being connected to the negative pole 12 of the electrical source 1 via a second contactor 5, the first and second contactors 4, 5 being independently controllable for their opening and closing.

[0022] The following part of the document describes an embodiment in which at least one high-voltage component 3 is a vehicle traction electrical network 3, and the high-voltage electrical source 1 is a traction battery 1 of the motor vehicle 100.

[0023] In one embodiment, the electrical traction network 3 of the motor vehicle 100 comprises a set of components dedicated to the operation of an electric traction chain including one or more electric motors and inverters and / or one or more converters and / or one or more chargers.

[0024] An embodiment of a high-voltage electrical circuit 10 is illustrated by [Fig.1].

[0025] The first and second contactors 4, 5 of circuit 10 allow alternative - to isolate the traction battery 1, in particular from the given branch 2 of the circuit supplying the traction electrical network 3 of the motor vehicle 100, by ordering an opening of the contactors 4, 5, or - to connect the traction battery 1, in particular to the given branch 2 of the circuit supplying the electrical traction network 3 of the motor vehicle 100, by ordering a closing of the contactors 4, 5.

[0026] The first and second contactors 4, 5 can be independently controlled to open and close. Therefore, when the traction electrical network 3 needs to be connected to the terminals 11, 12 of the high-voltage battery 1, contactor 4, 5 can be selected to close first; this contactor is also referred to as the designated contactor 4, 5 in the remainder of this document. In the remainder of this document, any contactor other than the designated contactor 4, 5 is referred to as the "closing contactor".

[0027] The high-voltage circuit 10 advantageously includes a DC converter 6 powered by a low-voltage battery 7. Before connecting the ends of the circuit branch 2 to the terminals of the high-voltage battery 11, 12, the current converter 6 can be controlled to generate a high-voltage DC current between the first end 21 and the second end 22 of the circuit branch 10 from a DC current supplied by the low-voltage battery 7. The controlled voltage V2 at the output of the current converter 6 is advantageously close to a voltage V1 measurable across the terminals of the high-voltage battery.

[0028] In one embodiment, the management device 50 according to the invention includes a means for measuring 9 a current voltage between the first end 21 and the second end 22 of the given branch 2.

[0029] In one embodiment, the management device 50 according to the invention includes a means 20 for determining a wear rate of the first and second contactor 4, 5. The means 20 for determining the wear rate may include an implementation of a modeling calculation of a wear rate, or an implementation of a physical measurement of the wear rate.

[0030] The management device 50 according to the invention comprises hardware and / or software elements configured to implement the method of managing a high-voltage electrical circuit according to the invention.

[0031] In particular, the device 50 for managing a high-voltage electrical circuit includes a processing unit 8 comprising a microprocessor 81, a memory 82 and communication interfaces 83.

[0032] The high-voltage electrical circuit management system, and particularly the microprocessor 81, mainly comprises the following modules which cooperate with each other: - a module 811 for increasing a voltage between the first end 21 and the second end 22 of the given branch 2, this module being able to cooperate with the converter 6 and a means 9 for measuring a current voltage, - a module 812 for selecting a given contactor taken from the first or second contactor 4, 5, this module being able to cooperate with a means 20 for determining the wear rate of a contactor 4, 5, then - a module 813 for controlling the closing of a given contactor, then - a module 814 for controlling a contactor closure other than the given contactor.

[0033] With reference to [Fig.3], a management process is described comprising four steps E1 to E4 which are executed successively.

[0034] In a first step El, we increase a voltage V2(t) between the first end 21 and the second end 22 of the given branch 2.

[0035] To achieve this, a target voltage is determined between the first end 21 and the second end 22 of the given branch, the target voltage being equal to a first voltage V1 measured across the terminals of the high-voltage battery 1. Advantageously, the value of this first voltage V1 is essentially constant over time.

[0036] A second voltage V2(t) is also measured; this is the voltage between the first end 21 and the second end 22 of the given branch 2. As long as the second voltage V2(t) is less than the first voltage VI, the DC converter 6 is controlled to increase the second voltage V2(t) (i.e., the voltage applied between the first and second ends 21, 22 of branch 2) until the second voltage V2(t) is substantially equal to the first voltage VI (i.e., the voltage measured across the high-voltage battery). In other words, the voltage increase between the first and second ends of the given branch is controlled to minimize the difference between a first voltage VI, measured across the high-voltage power source, and a second voltage V2(t) measured between the first and second ends of the given branch.

[0037] To generate a voltage increase between the first and second ends 21, 22 of the given branch 2, the DC converter 6 is powered by a low-voltage battery 7. The DC converter 6 is thus capable of generating a high-voltage DC current between the first and second ends from a DC current supplied by the low-voltage battery 6.

[0038] The first step El is illustrated by graphs G11 and G15 of [Eig.3].

[0039] Graph G11 illustrates a phase of operation of converter 6, between a time T1 and a time T4.

[0040] Graph G15 illustrates a time evolution of a voltage V2(t) applied by the converter 6 between the first end 21 and the second end 22 of the given branch 2. The voltage V2(t) increases between a time T1 and a time T1', until it reaches a value V2max close to the voltage V1 applied to the terminals 11, 12 of the high-voltage battery 1. As shown by graph G14 of [Fig. 3], the voltage VI is constant over time.

[0041] Then, the voltage V2(t) remains constant at a level V2max approximately equal to the voltage VI. However, a voltage difference between V2max and VI may persist. Indeed, the accuracy of the voltage sensors located at the terminals of the traction battery and the terminals of the vehicle's electrical traction network is insufficient to regulate the voltage V2max precisely enough to completely eliminate the voltage difference between VI and V2max.

[0042] In the rest of the document, the difference between the voltage VI and the voltage V2max is referred to as "voltage difference dV".

[0043] Then we proceed to step E2. In step E2, we select a given contactor taken from the first or second contactor 4, 5.

[0044] The given contactor is the contactor, chosen from the first and second contactors 4, 5, whose closing will be commanded first. The contactor other than the given contactor, named "closing contactor" will therefore be commanded to close after the given contactor has closed.

[0045] The closing contactor closes circuit 10, which connects the high-voltage battery to the vehicle's electrical traction system. As a result, the closing contactor is susceptible to an electric arc, which can cause wear. Indeed, when the circuit is closed, a non-zero voltage difference dV can generate an electric arc.

[0046] Therefore, it is advisable to alternate the contactor used to close the high-voltage circuit in order to extend the operating life of the assembly consisting of the first and second contactors. In other words, the choice of a given contactor influences the lifespan of each of the first and second contactors.

[0047] For this purpose, the selection of the given contactor includes the implementation of an alternating logic between the first and second contactor.

[0048] In one embodiment, the alternation logic includes a systematic alternation of a selection between the first and second contactor. In other words, the given contactor is alternately the first and then the second contactor.

[0049] Other embodiments of the alternating logic are conceivable. For example, in addition or alternatively, the alternating logic can take into account a wear rate of the first and second contactors, the given contactor being determined as the contactor with the highest wear rate, the wear rate of the first and second contactors being determined by the determination means 20.

[0050] We then proceed to a control step E3 to close the given contactor. This step is represented by graph G12 in [Fig.3]. At time T2, the closing of the given contactor is commanded.

[0051] Then we proceed to a control step E4 to close the closing contactor. This step is represented by graph G13 in [Fig.3]. At time T3, the closing contactor is commanded.

[0052] Thus, the method according to the invention makes it possible to reduce damage, by electric arcs, to the assembly formed by the first and second contactors. In one embodiment, the method according to the invention makes it possible to adapt the alternation logic between the first and second contactors based on available information on the wear rate of each contactor.

Claims

Demands

1. A method for managing a high-voltage electrical circuit (10) of a motor vehicle (100), the high-voltage electrical circuit (10) comprising - a high-voltage electrical source (1), having a positive pole (11) and a negative pole (12), - a given branch (2) of the high-voltage electrical circuit (10) supplying at least one high-voltage component (3), in particular the given branch supplying an electrical traction network (3) of the motor vehicle, a first end (21) of the given branch (2) being connected to the positive terminal (11) of the electrical source (1) via a first contactor (4), and a second end (22) of the given branch (2) being connected to the negative terminal (12) of the electrical source (1) via a second contactor (5), the first and second contactors (4, 5) being independently controllable for their opening and closing, the method being characterized in that it comprises an increase (E1) of a voltage (V2) between the first end (21) and the second end (22) of the given branch (2), then a closing of the high-voltage electrical circuit (10), comprising: - a selection (E2) of a given contactor (4, 5) taken from the first contactor (4) or the second contactor (5), then - a command (E3) to close the given contactor (4, 5), then - a control (E4) for closing the contactor (4, 5) other than the given contactor (4, 5), and in that the selection (E2) of the given contactor (4, 5) includes an implementation of an alternating logic between the first and second contactor (4, 5) so as to increase the lifetime of an assembly consisting of the first and second contactor (4, 5).

2. Management method according to the preceding claim, characterized in that the alternation logic includes a systematic alternation of a selection between the first and second contactor (4, 5).

3. Management method according to any one of the preceding claims, characterized in that the alternation logic takes into account a wear rate of the first and second contactor (4, 5), the given contactor (4, 5) being determined as the contactor (4, 5) exhibiting the highest wear rate.

4. Management method according to any one of the preceding claims, characterized in that the voltage increase (V2) between the first end (4) and the second end (5) of the given branch (2) is controlled so as to minimize a difference between a first voltage (VI), measured across the terminals of the high-voltage electrical source (1), and a second voltage (V2) measured between the first end (21) and the second end (22) of the given branch (2).

5. Management method according to the preceding claim, the high voltage circuit (10) further comprising a DC current converter (6) powered by a low voltage battery (7), the method being characterized in that the voltage increase (V2) between the first end (21) and the second end (22) of the given branch (2) is implemented by the current converter (6) capable of generating a high voltage DC current between the first end (21) and the second end (22) of the given branch (2) from a DC current supplied by the low voltage battery (7).

6. Device (50) for managing a high-voltage electrical circuit (10) of a motor vehicle (100), the device comprising hardware elements (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 20, 21, 22, 81, 82, 83) and / or software elements (811, 812, 813, 814) configured to implement the method according to any one of the preceding claims.

7. Motor vehicle (100) comprising a management device (50) for a high-voltage electrical circuit (10) according to the preceding claim.

8. A computer program product comprising program code instructions recorded on a computer-readable medium for implementing the steps of the process according to any one of claims 1 to 5 when said program runs on a computer or a computer program product downloadable from a communication network and / or recorded on a computer-readable medium computer-readable and / or computer-executable data, characterized in that it includes instructions which, when the program is executed by the computer, lead the computer to carry out [the steps of] the process according to any one of claims 1 to 5 [EPO directives formulation].

9. A computer-readable data recording medium on which is recorded a computer program comprising program code instructions for implementing the process according to any one of claims 1 to 5 or according to claim 8 or a computer-readable recording medium comprising instructions which, when executed by a computer, cause the computer to implement [the steps of] the process according to any one of claims 1 to 5 [EPO guidelines formulation];

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