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 embedded in a vehicle

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

[0002] Such an electrical network generally includes a fuse box connected on the one hand to a vehicle service battery, with a nominal open-circuit voltage generally of around 12V (volts), and on the other hand to one or more distribution boxes containing power transistors to supply the vehicle's electrical consumers.

[0003] These power transistors, called electronic switching components or "SmartMOS" in English, are chips comprising one or more transistors such as MOSFETs (metal-oxide-semiconductor field-effect transistors), controlled by a control circuit that can open a circuit in a short-circuit situation in 100 microseconds to 10 milliseconds. To achieve this, each of these components is equipped with a current measurement device that 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 significant software component.

[0004] Given the increasing number of transistors in this type of vehicle, the cost of the electrical network is substantial, especially since its various components must be sized to carry ever-increasing current. In particular, the circuit connecting each transistor to the battery comprises several elements: - a conductor wire, - a conductor busbar to which the conductor wire is connected, the conductor busbar being located in a distribution box and receiving current from several other conductor wires supplying other transistors, - a pin allowing the conductor busbar in the distribution box to be secured 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 true as their temperature rises with the current they carry. For example, a pin sized to receive a cable with a cross-section of 8 mm² (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 the new vehicles, it is therefore necessary to take into account the worst cases of temperature rise of all the elements of the circuits forming the electrical network, and therefore to 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 embedded in a vehicle, comprising the following steps: - Determination of the current flowing 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 supply is reduced has of course a non-zero electricity consumption before this reduction step.

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

[0011] Thanks to the invention, the various elements of the electrical network that are susceptible to overheating are kept at a temperature that allows for the maximum current flow. As a result, these various elements are not oversized but precisely sized, for example, to meet 80% of the vehicle's usage scenarios, which makes it possible to build the electrical network using more compact and lighter components than in the prior art.

[0012] In particular, the cross-sections of certain wiring wires or power lines, and the cross-sections of certain pins, are reduced thanks to the invention, thereby lowering their costs. Furthermore, the size of the plastic connectors incorporating these reduced-section pins on the distribution boxes is also reduced, thus minimizing the overall size of the electrical network within the vehicle.

[0013] The current is determined, for example, by adding together current measurements passing through each of the electronic switching devices that individually protect the electrical consumers served by the conductive element. Thus, the management process reuses current measurement means already present in the vehicle, which does not entail any significant additional implementation cost.

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

[0015] The reduction step includes, for example, sending a request to reduce consumption to a management body of the electrical consumer, or an order to open an electronic disconnection device serving the electrical consumer individually.

[0016] Thus, when the electrical consumer has a control device that allows for reducing its consumption, such a reduction is preferred to completely cutting off the power supply to the consumer. This is particularly possible for all electrical consumers with an energy-saving operating mode.

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

[0018] Furthermore, the unsafe electrical consumer is preferentially 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 non-safe electrical consumers is as transparent as possible to vehicle users. An example of an electrical consumer whose action is not directly perceptible to a vehicle user is the defroster or heater, which can be temporarily reduced. An example of an accessory electrical consumer is a 12V accessory socket.

[0020] In one embodiment of the invention, the reduction step is followed by a further current determination step and a further comparison step, and if, during the further comparison step, the current determined during the further current determination step is greater than the current threshold, then the further comparison step is followed by a step of reducing the power supply to at least one other unsafe electrical load among the loads electrical. This ensures the electrical consumption of the vehicle's safety equipment.

[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 amount of current, then the new comparison step is followed by a step to restore a nominal power supply to the electrical consumer. This makes the unsafe power load shedding of the electrical consumer temporary and minimizes disruption to vehicle users.

[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 passing through a conductive element supplying several electrical consumers, - means for comparing the current determined by the means of determination, with a current threshold, capable of activating means for reducing the electrical supply to at least one unsafe electrical consumer among the electrical consumers, when the current determined is greater than the current threshold.

[0023] The reduction means include, for example, means for sending a request to reduce consumption to a management body of at least one of the electrical consumers, and means for controlling the opening of at least one electronic disconnecting device serving one of the electrical consumers individually.

[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 features and advantages of the invention will become apparent from the following description on the one hand, and from several illustrative and non-limiting examples of embodiments given by reference to the accompanying 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 process according to the invention, of the distribution of electrical energy in the electrical network of [Fig.1], implemented by the management device of [Fig.1], in this embodiment of the invention.

[0029] In one embodiment of the invention, an electrical network 30, represented [Fig. 1], is installed in a vehicle. It provides electrical power to electrical consumers C1, C2, C3, C4 of the vehicle, from a so-called auxiliary battery 40, with a nominal open-circuit voltage, for example, of 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 enabling the opening or closing of a window of the vehicle.

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

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

[0034] In this electrical network 30, each electrical consumer C1, C2, C3, C4 is individually protected by an electronic switching device 32, 34, 36, 38 respectively, arranged in a distribution box. Each of the electronic switching devices 32, 34, 36, 38 is connected by a conductive wire or a conductive track in the distribution box to a conductive busbar 39, which is itself connected to a pin 352 of a connector 35. A power line connects pin 352 to a fuse 31 in 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 switching elements are, for example, MOSFET transistors of different sizes. A control circuit allows them to be controlled and includes, for this purpose, means for measuring the currents i1, i2, i3, and i4 passing respectively through each of the electronic switching elements 32, 34, 36, and 38.

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

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

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

[0039] The method 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 process 100 is the determination of the current I passing through the pin 352. This determination step 110 is implemented for example by the processor 24 by adding the measurements of the currents i1, i2, i3 and i4 flowing in the electrical switching elements 32, 34, 36 and 38, carried out by the measurement means of the control circuit of these electrical switching elements 32, 34, 36 and 38.

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

[0042] The next step 130 is the comparison, by the calculator 20, of the current I determined previously in the determination step 110, with a current threshold S associated with the pin 352. This current threshold S is strictly less 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 on [Fig.2]), then the next step is a step 140 of reducing the power supply to 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 on [Fig.2]) the next step is a step 150 of checking the value of a meter n, as described later.

[0044] We now move to step 140, at the beginning of which the current I passing through pin 352 is greater than or equal to the threshold S. This use case can occur for example in winter, with all the electrical consumers Cl, C2, C3, and C4 operating at the same time, the signal light being activated (electrical consumer Cl), the defrosting also (electrical consumer C4) and the kettle connected to 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, we seek to reduce this current I so that the traffic light (electrical consumer Cl), which is an electrical consumer To ensure safety, the system can continue to function normally. To achieve this, control unit 20 commands the opening of the electronic cutoff device 38, which supplies power to the electrical consumer C4, i.e., the vehicle's defrosting system. This load shedding method is chosen because the defrosting system is unsafe, consumes a significant amount of electricity, and its temporary deactivation will not be immediately noticeable to a vehicle user. This would not be the case if, instead, control unit 20 cut the power to the accessory socket (electrical consumer C3) while it is connected to a kettle in operation, or if control unit 20 cut the power to the electric motor (electrical consumer C2) of the window to be opened.

[0046] At the end of step 140, the calculator 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 period, the control device 1 repeats step 110 and refreshes the current value I during the new determination step 110. If, during the new comparison step 130 following this new step 110, the current I is still above the current threshold S, the control unit 20 implements a new step 140 to reduce 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 disconnect device 36 corresponding to the accessory socket, increments the counter n by one, and loops back to the determination step 110 after a further waiting period of one second.

[0048] We now proceed to step 150, at the beginning of which the current I flowing 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 occurred. If the counter does indeed have a zero value (branch N corresponding to step 150 in [Fig. 2]), then the computer 20 loops back to the determination step 110.

[0049] If, on the other hand, the meter has a value strictly greater than zero (branch Y corresponding to step 150 in [Fig. 2]), then the next step is a step 160 comparing the difference between the current threshold S and the current I, as determined during the last iteration of the preceding step 110, with a predefined quantity of current AI, for example 5 A. This predefined quantity of current AI is determined so as to be compatible with restoring the electrical load, which was disconnected from its supply in iteration n-1 of the reduction step 140, without altering the operation of the safety load Cl. The predefined quantity of current AI therefore depends, in particular, on the electrical load, which was disconnected from its supply in 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 for restoring the power supply to the electrical consumer, which had been cut off in iteration n-1 of step 140 for reducing the power supply to an electrical consumer. For example, if only the electrical consumer C4 had been previously unloaded, then in this step 170, the computer 20 commands the closure of the electrical switching device 38. Then the computer loops back to the determination step 110, after a waiting time of, for example, one second.

[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 on [Fig.2]), then the calculator 20 loops back to the determination step 110, after a waiting time of one second for example.

[0052] After a predefined number of successive iterations of step 160 that do not lead to a recovery step 170, the computer 20 may stop these iterations. The electrical consumer whose power supply was cut off in iteration n-1 of the reduction step 140 will then only be powered again when there is a change in the 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 just described, and many modifications 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 in the comparison step 130, or with respect to the predefined quantity of current AI in step 160, can be replaced by strict inequality conditions without changing the nature of the invention.

Claims

Demands

1. A 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 current (I) determination step (110) with a current threshold (S), and if the current (I) determined 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 (C3, C4) among the electrical consumers (Cl, C2, C3, C4), the method being characterized in that the current threshold is determined so that the temperature of the conductive element does not exceed 85°C.

2. Method of managing (100) the distribution of electrical energy in an electrical network (30) according to claim 1, wherein the reduction step (140) comprises sending a request to reduce consumption to a management device of the electrical consumer (C3, C4), or an opening command of an electronic disconnecting device (36, 38) serving the electrical consumer (C4) individually.

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

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

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

6. Method of managing (100) the distribution of electrical energy in an electrical network (30) according to claim 5, wherein, if during the new comparison step (130), the current (I) determined during the new determination step (110) of the current (I) is less 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 restoration step (170) of a nominal supply of the electrical consumer (C3, C4).

7. Device for managing the distribution of electrical energy in an electrical network (30) on board a vehicle, comprising: - means for determining (24) a current (I) passing through a conductive element (352) supplying several electrical consumers (Cl, C2, C3, C4), - means for comparing (24) the current (I) determined by the means for determining (24), with a current threshold (S), capable of activating means for reducing the electrical supply to at least one unsafe electrical consumer (C3, C4) among the electrical consumers (Cl, C2, C3, C4), when the current (I) determined is greater than the current threshold (S), the management device being characterized in that the current threshold is determined so that the temperature of the conductive element does not exceed 85°C.

8. Management device (1) according to claim 7, wherein 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 device of

9. cut (36, 38) individually serving one of the electrical consumers (C3, C4). Vehicle comprising an electrical network (30), and a device for managing (1) the distribution of electrical energy in the electrical network (30) according to claim 7 or 8.

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