Method and device for managing the distribution of electrical energy in an electrical network embedded in a vehicle

Abstract

Method and device for managing the distribution of electrical energy in an electrical network embedded in a vehicle. The present invention relates to a method (100) for managing the distribution of electrical energy in an electrical network embedded in a vehicle, comprising the steps of: - determining (110) a current (I) passing through a conductive element supplying several electrical consumers, - comparing (130) the current (I) determined during the current (I) determination step (110) with a current threshold (S), and if the determined current (I) is greater than the current threshold (S), the comparison step (130) is followed by a step of reducing the electrical supply to at least one unsafe electrical consumer among the electrical consumers. (Figure 2)

Description

Title of the invention: Method and device for managing the distribution of electrical energy in an electrical network on board a vehicle

[0001] The present invention relates to the fields of electricity and automobiles, and more specifically concerns a method and a device for managing the distribution of electrical energy in an electrical network on board a vehicle.

[0002] Such an electrical network generally comprises a fuse box connected on the one hand to a service battery of the vehicle, with a nominal no-load voltage generally of the order of 12V (volts), and on the other hand to one or more distribution boxes comprising power transistors for supplying the electrical consumers of the vehicle.

[0003] These power transistors, called electronic cut-off components or "SmartMOS" in English, are chips containing one or more transistors such as MOSFET transistors (for "metal-oxide-semiconductor field-effect transistor"), controlled by a control circuit allowing a circuit to be opened in a short-circuit situation in 10qs (microseconds) to 10ms (milliseconds). For this, each of these components is equipped with a current measurement which is used by the control circuit. These new components therefore have the advantage of meeting the safety requirements of motor vehicles, particularly those with a high software component.

[0004] Given the increasing number of transistors in this type of vehicle, the cost of the electrical network is significant, especially since its various elements must be sized to carry ever-increasing current. In particular, the circuit connecting each transistor to the battery comprises several elements: - a common thread, - a conductive bar to which the conductive wire is connected, the conductive bar being arranged in a distribution box and receiving current from several other conductive wires supplying other transistors, - a pin for securing the conductive bar in the distribution box to a power line, - the power line, itself connected to a fuse in the fuse box, - the fuse and its connection to the battery.

[0005] All these elements limit the capacity to distribute current, and this is all the more so as they increase in temperature with the current they carry. For example, a pin sized to receive a cable with a cross-section of 8mm2 (square millimeters), can pass 70A (amperes) as long as its temperature remains below 50°C (degrees Celsius), but cannot pass more than 60A at a temperature above 60°C, nor more than 40A at a temperature above 100°C.

[0006] To take into account the multiple uses of new vehicles, we must therefore take into account the worst cases of temperature rise of all the elements of the circuits forming the electrical network, and therefore oversize these elements in order to pass the current necessary for the operation of the electrical consumers, which makes the electrical network very expensive.

[0007] The present invention aims to remedy at least in part the aforementioned drawbacks by providing a method and a device for managing the distribution of electrical energy in an electrical network on board a vehicle, as well as a corresponding vehicle, which make it possible not to oversize this electrical network.

[0008] To this end, the invention proposes a method for managing the distribution of electrical energy in an electrical network on board a vehicle, comprising steps of: - determination of a current passing through a conductive element supplying several electrical consumers, - comparison of the current determined during the current determination step, with a current threshold, and if the determined current is greater than the current threshold, the comparison step is followed by a step of reducing the power supply to at least one unsafe electrical consumer among the electrical consumers.

[0009] The electrical consumer whose power supply is reduced of course has a non-zero electricity consumption before this reduction step.

[0010] The current threshold is for example determined so that the temperature of the conductive element does not exceed 85°C.

[0011] Thanks to the invention, it is ensured that the various elements of the electrical network likely to overheat remain at a temperature allowing a maximum current to pass. As a result, these various elements are not oversized but dimensioned as precisely as possible, for example to satisfy 80% of the vehicle's use cases, which makes it possible to produce the electrical network using more compact and lighter parts than in the prior art.

[0012] In particular, the wiring sections of certain conductive wires or power lines, and the sections of certain pins, are reduced thanks to the invention, which reduces their costs. In addition, the size of the plastic connectors comprising these reduced-section pins, on the distribution boxes, is also reduced, which makes it possible to reduce the size of the electrical network in the vehicle.

[0013] The current is determined, for example, by adding measurements of current passing through each of the electronic cut-off devices individually protecting the electrical consumers served by the conductive element. Thus the management method reuses current measurement means already present in the vehicle, which does not bring any significant additional cost in its implementation.

[0014] Alternatively, the determination of the current uses a current measurement directly at the level of the conductive element.

[0015] The reduction step comprises, for example, sending a request to reduce consumption to a management unit of the electrical consumer, or a command to open an electronic cut-off unit serving the electrical consumer individually.

[0016] Thus, when the electrical consumer includes a management device making it possible to reduce the consumption of the electrical consumer, such a reduction is preferred rather than completely cutting off the power supply to the electrical consumer. This is particularly possible for all electrical consumers including an energy-saving operating mode.

[0017] According to an optional characteristic of the management method according to the invention, the unsafe electrical consumer is chosen from among electrical consumers consuming more than 10 watts. In fact, the largest electrical consumers such as heating, defrosting or air conditioning are preferably relieved of energy, so as to penalize the fewest possible consumers, activated by the user(s) of the vehicle.

[0018] Furthermore, the non-safe electrical consumer is preferably chosen by default from among electrical consumers whose action is not directly perceptible to a user of the vehicle, or, if these do not consume energy, from among accessory electrical consumers of the vehicle.

[0019] Thus, the energy load shedding of the unsafe electrical consumer is as transparent as possible for the vehicle users. An electrical consumer whose action is not directly perceptible to the user of a vehicle is, for example, defrosting or heating, which can be temporarily reduced. An accessory electrical consumer is, for example, a 12V accessory socket.

[0020] In one embodiment of the invention, the reduction step is followed by a new step of determining the current and a new comparison step, and if during the new comparison step, the current determined during the new current determination step is greater than the current threshold, then the new comparison step is followed by a step of reducing the power supply of at least one other non-safe electrical consumer among the electrical consumers. This ensures the electrical consumption of the safety equipment. of the vehicle.

[0021] In this embodiment of the invention, if on the contrary during the new comparison step, the current determined during the new current determination step is lower than the current threshold, and if the difference between the current threshold and the current determined during the new determination step is greater than a predefined quantity of current, then the new comparison step is followed by a step of restoring a nominal power supply to the electrical consumer. This makes it possible to make the power shedding of the electrical consumer unsafe temporarily, and to inconvenience the users of the vehicle as little as possible.

[0022] The invention also relates to a device for managing the distribution of electrical energy in an electrical network on board a vehicle, comprising: - means for determining a current flowing in a conductive element supplying several electrical consumers, - means for comparing the current determined by the determination means with a current threshold, capable of activating means for reducing the power supply to at least one unsafe electrical consumer among the electrical consumers, when the determined current is greater than the current threshold.

[0023] The reduction means comprise, for example, means for sending a request to reduce consumption to a management unit of at least one of the electrical consumers, and means for controlling the opening of at least one electronic cut-off unit individually serving one of the electrical consumers.

[0024] The invention finally relates to a vehicle comprising an electrical network, and a device for managing the distribution of electrical energy in the electrical network according to the invention.

[0025] The management device according to the invention and the vehicle according to the invention have advantages similar to the management method according to the invention.

[0026] Other characteristics and advantages of the invention will become apparent from the following description on the one hand, and from several exemplary embodiments given for informational and non-limiting purposes with reference to the attached schematic drawings on the other hand, in which:

[0027] [Fig-1] represents an electrical network of a vehicle, and a management device according to the invention of the distribution of electrical energy in this electrical network, in one embodiment of the invention, and

[0028] [Fig.2] represents steps of a management method according to the invention, of the dis electrical energy distribution in the electrical network of [Fig.l], implemented by the management device of [Fig.l], in this embodiment of the invention.

[0029] In one embodiment of the invention, an electrical network 30 shown [Fig.l], is embedded in a vehicle. It makes it possible to electrically supply electrical consumers C1, C2, C3, C4 of the vehicle, from a so-called service battery 40, with a nominal no-load voltage of, for example, 12V.

[0030] The electrical consumer Cl is for example a lighting device such as a traffic light.

[0031] The electrical consumer C2 is for example an electric motor allowing a window of the vehicle to be opened or closed.

[0032] The electrical consumer C3 is for example a 12V accessory socket, into which a user has connected a kettle.

[0033] The electrical consumer C4 is, for example, a defrosting system for the vehicle windows.

[0034] In this electrical network 30, each electrical consumer C1, C2, C3, C4 is individually protected by an electronic cut-off device 32, 34, 36, 38 respectively, arranged in a distribution box. Each of the electronic cut-off devices 32, 34, 36, 38 is connected by a conductive wire or a conductive track in the distribution box, to a conductive bar 39 itself connected to a pin 352 of a connector 35. A power line connects the pin 352 to a fuse 31 of a fuse box, via a connector 33 of the fuse box. The fuse box is connected to the positive terminal of the battery 40 by a power conductor.

[0035] The electronic cut-off devices are, for example, MOSFET transistors of different calibers. A control circuit allows them to be controlled and for this purpose comprises means for measuring the currents i1, i2, i3, and i4 passing respectively in each of the electronic cut-off devices 32, 34, 36 and 38.

[0036] The measurements carried out by the measuring means are fed back via an analog / digital converter 18 to a computer 20 of the vehicle, comprising an input port 22, a processor 24 and a memory 26, for example a RAM memory (from the English “Random Access Memory”) or a ROM memory (from the English “Read Only Memory”). The communication between the analog / digital converter 18 and the computer 20 is done for example via a CAN bus (from the English “Controller Area Network”).

[0037] In order to prevent overheating of the conductive element constituted by the pin 352, for example due to the fact that all the electrical consumers C1, C2, C3, C4 operate at the same time, a management method 100 (referenced [Fig.2]) according to the invention for the distribution of electrical energy in the electrical network 30, is implemented in a management device 1 according to the invention for this distribution of electrical energy.

[0038] The management device 1 comprises the computer 20 and the means for measuring the currents i1, i2, i3 and i4.

[0039] The method 100 for managing the distribution of electrical energy in the electrical network 30 is now described in relation to [Fig. 2]. It is implemented in hardware and software, in the management device 1.

[0040] A first step 110 of the management method 100 is the determination of the current I passing through the pin 352. This determination step 110 is for example implemented by the processor 24 by adding the measurements of the currents i1, i2, i3 and i4 flowing in the electrical cut-off members 32, 34, 36 and 38, carried out by the measurement means of the control circuit of these electrical cut-off members 32, 34, 36 and 38.

[0041] We therefore have: I = il + i2 + i3 + i4

[0042] The following step 130 is the comparison, by the computer 20, of the current I determined previously during the determination step 110, with a current threshold S associated with the pin 352. This current threshold S is strictly lower than the limit current that the pin 352 can withstand. It is determined so that the temperature of the pin does not exceed a temperature that can limit the current passing through the pin, this temperature being for example 85°C.

[0043] If during this comparison step 130, the current I is greater than or equal to the current threshold S (branch Y corresponding to step 130 in [Fig.2]), then the following step is a step 140 of reducing the electrical power supply of at least one of the electrical consumers C2, C3, and C4, assuming these electrical consumers are in operation, otherwise (branch N corresponding to step 130 in [Fig.2]) the following step is a step 150 of verifying the value of a counter n, as described later.

[0044] We now move to step 140, at the start of which the current I passing through pin 352 is greater than or equal to threshold S. This use case can occur for example in winter, with all electrical consumers C1, C2, C3, and C4 operating at the same time, the signal light being activated (electrical consumer C1), the defrosting also (electrical consumer C4) and the kettle plugged into the 12V accessory socket also (electrical consumer C3), while a user of the vehicle opens a window of the vehicle, thus activating the electric motor of this window (electrical consumer C2).

[0045] In this step 140, an attempt is made to reduce this current I so that the signal light (electrical consumer C1), which is a safe electrical consumer, can continue to operate nominally. For this, the computer 20 controls the opening of the electronic cut-off device 38 supplying the electrical consumer C4, i.e. the vehicle's defrosting system. The choice of this load shedding is motivated by the fact that the defrosting system is unsafe, uses a lot of electricity and that its temporary inhibition will not be immediately visible to a vehicle user. This would not be the case if instead, the computer 20 cut the power supply to the accessory socket (electrical consumer C3) while it is connected to a kettle in operation, or if the computer 20 cut the power supply to the electric motor (electrical consumer C2) of the window to be opened.

[0046] At the end of step 140, the computer 20 increments by one unit, the counter n initialized to zero, then loops back to step 110 of determining the current I in pin 352, after a waiting time of one second for example.

[0047] After this waiting time, the management device 1 therefore repeats step 110 and refreshes the value of the current I during the new determination step 110. In the case where during the new comparison step 130 following this new step 110, the current I is still greater than the current threshold S, the computer 20 implements a new step 140 of reducing the power supply to one of the non-safe electrical consumers C2 or C3 in operation. For example, it commands the opening of the electronic cut-off device 36 corresponding to the accessory socket, increments the counter n by one unit and loops back to the determination step 110, after a new waiting time of one second.

[0048] We now move to step 150, at the beginning of which the current I passing through pin 352 is strictly less than the threshold S. In this case, the computer 20 checks that the counter n is zero, i.e. that no electrical load shedding has previously taken place. If the counter actually has the value zero (branch N corresponding to step 150 in [Fig.2]), then the computer 20 loops back to the determination step 110.

[0049] If, on the contrary, the counter has a value strictly greater than zero (branch Y corresponding to step 150 in [Fig. 2]), then the next step is a step 160 of comparing the difference between the current threshold S and the current I, as determined during the last iteration of the previous step 110, with a predefined quantity of current AI, for example 5A. This predefined quantity of current AI is determined so as to be compatible with a restoration of the electrical consumer relieved of its power supply at iteration n-1 of the reduction step 140, without altering the operation of the safety consumer C1. The predefined quantity of current AI therefore depends in particular on the electrical consumer relieved of its power supply at iteration n-1 of the reduction step 140.

[0050] If the difference between the current threshold S and the current I is greater than or equal to this predefined quantity of current AI (branch Y corresponding to step 160 in [Fig.2]), then the next step is a step 170 of restoring the power supply to the electrical consumer, which had been cut off at iteration n-1 of step 140 of reducing the power supply of an electrical consumer. For example, if only the electrical consumer C4 had been previously unloaded, then during this step 170, the computer 20 commands the closing of the electrical cut-off device 38. Then the computer loops back to the determination step 110, after a waiting time of one second for example.

[0051] If, on the contrary, at step 160, the difference between the current threshold S and the current I is strictly less than this predefined quantity of current AI (branch N corresponding to step 160 in [Fig.2]), then the computer 20 loops back to the determination step 110, after a waiting time of one second for example.

[0052] At the end of a predefined number of successive iterations of step 160 not leading to a restoration step 170, the computer 20 possibly stops these iterations. The electrical consumer whose power supply had been cut off at iteration n-1 of the reduction step 140 will then only be powered again during a change of use or operation of the vehicle (for example upon detection of a stoppage of the electric motor corresponding to the electrical consumer C2).

[0053] Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention. In particular, the non-strict inequality conditions with respect to the current I during the comparison step 130, or with respect to the predefined current quantity AI in step 160, can be replaced by strict inequality conditions without changing the nature of the invention.

Claims

Claims

1. Method for managing (100) the distribution of electrical energy in an electrical network (30) on board a vehicle, comprising steps of: - determining (110) a current (I) passing through a conductive element (352) supplying several electrical consumers (Cl, C2, C3, C4), - comparing (130) the current (I) determined during the step of determining (110) the current (I), with a current threshold (S), and if the determined current (I) is greater than the current threshold (S), the comparison step (130) is followed by a step of reducing (140) the electrical supply of at least one unsafe electrical consumer (C3, C4) among the electrical consumers (Cl, C2, C3, C4).

2. Method for managing (100) the distribution of electrical energy in an electrical network (30) according to claim 1, in which the reduction step (140) comprises sending a request for reducing consumption to a management unit of the electrical consumer (C3, C4), or else a command to open an electronic cut-off unit (36, 38) individually serving the electrical consumer (C4).

3. Method for managing (100) the distribution of electrical energy in an electrical network (30) according to claim 1 or 2, in which the non-safe electrical consumer (C3, C4) is chosen from electrical consumers consuming more than 10 watts.

4. Method for managing (100) the distribution of electrical energy in an electrical network (30) according to any one of claims 1 to 3, in which the non-safe electrical consumer (C3, C4) is chosen by default from electrical consumers (C4) whose action is not directly perceptible to a user of the vehicle, or, if these do not consume energy, from accessory electrical consumers (C3) of the vehicle.

5. Method for managing (100) the distribution of electrical energy in an electrical network (30) according to any one of claims 1 to 4, in which the reduction step (140) is followed by a new step of determining (110) the current (I) and a new comparison step (130), and if during the new comparison step (130), the current (I) determined during the new step of determining (110) the current (I) is greater than the current threshold (S), then the new comparison step (130) is followed by a step of reducing (140) the power supply of at least one other unsafe electrical consumer (C3) among the electrical consumers.

6. Method for managing (100) the distribution of electrical energy in an electrical network (30) according to claim 5, in which, if during the new comparison step (130), the current (I) determined during the new determination step (110) of the current (I) is lower than the current threshold (S), and if the difference between the current threshold (S) and the current (I) determined during the new determination step (110) is greater than a predefined quantity (AI) of current, then the new comparison step (130) is followed by a step of restoring (170) a nominal power supply to the electrical consumer (C3, C4).

7. Device (1) for managing the distribution of electrical energy in an electrical network (30) on board a vehicle, comprising: - means (24) for determining a current (I) passing through a conductive element (352) supplying several electrical consumers (Cl, C2, C3, C4), - means (24) for comparing the current (I) determined by the determining means (24), with a current threshold (S), capable of activating means (22) for reducing the electrical supply of at least one unsafe electrical consumer (C3, C4) among the electrical consumers (Cl, C2, C3, C4), when the determined current (I) is greater than the current threshold (S).

8. Management device (1) according to claim 7, in which the reduction means (22) comprise means for sending a consumption reduction request to a management unit of at least one of the electrical consumers (C3, C4), and means for controlling the opening of at least one electronic cut-off unit (36, 38) individually serving one of the electrical consumers (C3, C4).

9. Vehicle comprising an electrical network (30), and a device (1) for managing the distribution of electrical energy in the electrical network (30) according to claim 7 or 8.

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