Converter control device, vehicle and associated control method

Abstract

The invention relates to a control device (10) for a converter (8) arranged between a battery (4) and an on-board network (6), the control device comprising a control module (15), a pilot module (16), and a safety module (17): the control module being configured to deliver a control signal (ST) for the converter; the pilot module being configured to apply a pilot signal (SR) to the converter as a function of the control signal; the control module being configured to, in the event of an overvoltage on the on-board network, command a suspension of electrical power transfer by the converter; the safety module being configured to, in response to the overvoltage: verify the conformity of the pilot signal with said suspension; and trigger a shutdown of the converter in the event of non-conformity. Figure 1

Description

Title of the invention: Converter control device, vehicle and associated control method Technical field

[0001] The present invention relates to a control device for a converter intended to be on board a motor vehicle and arranged in use between a high voltage network of the motor vehicle, associated with a first direct voltage, and a low voltage network of the motor vehicle, associated with a second direct voltage lower than the first voltage.

[0002] The invention also relates to a vehicle comprising such a control device, a control method and a computer program.

[0003] The invention applies to the field of vehicles, and more specifically to electric vehicles comprising a battery intended to supply an on-board circuit of the vehicle. State of the art

[0004] In the field of electric vehicles, particularly electric automobiles, it is known to use a converter to transfer electrical power between a battery on board the vehicle and an on-board network of the vehicle.

[0005] In particular, such a converter is intended to convert a first direct voltage (called "high voltage", typically of the order of 400 V), supplied by the battery, into a second direct voltage (called "low voltage", for example 12 V), available for the electrical equipment connected to the on-board network.

[0006] In order to protect the electrical components connected to the on-board network, it is known to detect overvoltages at the converter output, and to provide a response to such a situation based on a supposed cause of the overvoltage. More specifically, if the overvoltage results from a malfunction of the converter, stopping the converter is required. Conversely, if the overvoltage is due to a fault external to the converter, interrupting the transfer of electrical energy is desirable, but the converter must be ready to transfer electrical energy again as soon as the overvoltage disappears. The origin of the overvoltage must therefore be determined unambiguously.

[0007] Conventionally, to determine the origin of the overvoltage, it is known to monitor, by means of a current sensor, a sign of the current delivered by the converter to the on-board network: a positive current (i.e. flowing from the converter to the on-board network) is considered to be indicative of a fault in the converter itself.

[0008] However, such a method does not give complete satisfaction.

[0009] Indeed, in the event of a failure of the current sensor, it is no longer possible to determine reliably the cause of the surge.

[0010] An aim of the present invention is to remedy at least one of the drawbacks of the state of the art.

[0011] Another object of the invention is to propose a device which is capable of determining more reliably the origin of the overvoltage, even in the event of failure of the current sensor.

[0012] Another object of the invention is to propose a device which responds effectively to overvoltage. Statement of the invention

[0013] To this end, the invention relates to a control device of the aforementioned type, comprising a control module, a piloting module and a safety module: • the control module being configured to deliver a control signal associated with an operating instruction of the converter, in particular an operation according to a first operating mode in which the converter transfers electrical energy from the high voltage network to the low voltage network, • the control module being configured to apply, to the converter, a control signal depending on the control signal, so as to control the converter in accordance with the operating instruction, • the control module being, in addition, configured to, in response to the detection of an overvoltage at the low voltage network during the first operating mode, deliver a control signal for a suspension of the transfer of electrical energy from the high voltage network to the low voltage network by the converter; • the safety module being configured to, in response to the detection of an overvoltage at the low voltage network during the first operating mode: • verify compliance of the control signal with a suspension of the transfer of electrical energy from the high voltage network to the low voltage network by the converter; and • trigger a shutdown of the converter in the event of a discrepancy between the control signal and said suspension of the transfer of electrical energy.

[0014] Indeed, thanks to the verification of the conformity (or not) of the pilot signal with By suspending the transfer of electrical energy, it becomes possible to determine whether the overvoltage results from a converter malfunction, without resorting to measuring the current delivered by the converter to the low-voltage network. Triggering an appropriate response (for example, stopping the converter) is then possible.

[0015] Advantageously, the control device according to the invention has one or more of the following characteristics, taken in isolation or in any technically possible combination:

[0016] the control device further comprises a voltage sensor configured to deliver a voltage measurement signal indicative of a voltage of the low voltage network;

[0017] the control device is also configured to, in the event of detection of an overvoltage at the low voltage network during the first operating mode: • determine a sign of a current flowing from the converter to the low voltage network; and • trigger the converter to stop if said current is positive;

[0018] The control device is also configured to, in response to the detection of an overvoltage at the low voltage network during the first operating mode and in the event of concordance between the control signal and said suspension of the transfer of electrical energy, control the converter according to a second operating mode to cause the converter to transfer electrical energy from the low voltage network to the high voltage network.

[0019] The device according to the invention can be any type of device such as a server, a computer, a tablet, a calculator, a processor, a computer chip, programmed to implement the method according to the invention, for example by executing the computer program according to the invention.

[0020] According to another aspect of the invention, there is provided a vehicle comprising a control device as defined above, a battery forming the high voltage network, an on-board network forming the low voltage network, and a converter connected between the battery and the on-board network, the control device being connected to the converter to control the operation of the converter.

[0021] According to another aspect of the invention, there is proposed a method for controlling a converter on board a motor vehicle and arranged between a high voltage network of the motor vehicle, associated with a first direct voltage, and a low voltage network of the motor vehicle, associated with a second direct voltage lower than the first voltage, the control method comprising the steps: • supplying at the output, by a control module, a control signal associated with an operating instruction of the converter, in particular according to a first operating mode in which the converter transfers electrical energy from the high voltage network to the low voltage network; and • application, to the converter, by a control module, of a control signal depending on the control signal, to control the converter in accordance with the operating instruction, the control method further comprising, in response to the detection of an overvoltage at the low voltage network during the first operating mode, the steps: • supply at the output, by the control module, of a control signal for suspension of the transfer of electrical energy from the high voltage network to the low voltage network by the converter; • verification, by a safety module separate from the control module and the pilot module, of compliance of the pilot signal with a suspension of the transfer of electrical energy from the high voltage network to the low voltage network by the converter; and • triggering, by the safety module, of a shutdown of the converter in the event of a discrepancy between the control signal and said suspension of the transfer of electrical energy.

[0022] Advantageously, the control method according to the invention has one or more of the following characteristics, taken in isolation or in any technically possible combination:

[0023] the method also comprises, in the event of detection of an overvoltage at the low voltage network when the converter is controlled according to the first operating mode, the steps: • determination of a sign of a current flowing from the converter to the low voltage network; and • triggering the converter shutdown if said current is positive;

[0024] the method further comprises, in the event of concordance between the control signal and said suspension of the transfer of electrical energy, controlling the converter according to a second operating mode to cause the converter to transfer electrical energy from the low voltage network to the high voltage network;

[0025] the high voltage network is a battery on board a vehicle, and in which the low voltage network is an on-board network of the vehicle.

[0026] According to another aspect of the invention, there is provided a computer program comprising executable instructions which, when executed by computer, implement the steps of the method as defined above.

[0027] The computer program can be in any computer language, such as for example machine language, C, C++, JAVA, Python, etc. Brief description of the figures

[0028] The invention will be better understood on reading the following description, given solely by way of non-limiting example and made with reference to the appended drawings in which:

[0029] [Fig.l] is a schematic representation of a vehicle according to the invention.

[0030] It is understood that the embodiments which will be described below do not are in no way limiting. In particular, it is possible to imagine variants of the invention comprising only a selection of characteristics described below isolated from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention compared to the state of the prior art. This selection includes at least one preferably functional characteristic without structural details, or with only part of the structural details if it is this part which is only sufficient to confer a technical advantage or to differentiate the invention compared to the state of the prior art.

[0031] In particular, all the variants and all the embodiments described can be combined with each other if nothing prevents this combination from a technical point of view. Detailed description

[0032] A vehicle 2 according to the invention is illustrated by [Fig.l]. The vehicle 2 is, in particular, an electric vehicle, or even a hybrid vehicle. For example, the vehicle 2 is an automobile.

[0033] The vehicle 2 has a battery 4, an on-board network 6, a converter 8 connected between the battery 4 and the on-board network 6, and a control device 10 connected to the converter 8.

[0034] The vehicle 2 further comprises a voltage sensor 11 configured to deliver a voltage measurement signal indicative of a voltage of the on-board network 6.

[0035] Optionally, the vehicle 2 also comprises a current sensor 12 configured to deliver a current measurement signal indicative of an intensity of a current flowing from the converter 8 to the on-board network 6.

[0036] The battery 4 is configured to store electrical energy, and is connected to first terminals 13 of the converter 8. The battery 4 is associated with a first direct voltage, in particular the nominal voltage of the battery 4 (for example of the order of 400 V), thus forming a first electrical network, called a “high voltage network”.

[0037] The on-board network 6 is connected to second terminals 14 of the converter 8, and is, for example, intended to supply electrical devices on board the vehicle 2. The on-board network 6 is associated with a second direct voltage, in particular the nominal operating voltage (for example, 12 V) of the on-board electrical devices (for example, a so-called “low voltage” battery), thus forming a second electrical network, called a “low voltage network”.

[0038] The converter 8 is adapted to transfer electrical energy between the high voltage network and the low voltage network, i.e. between the battery 4 and the on-board network 6.

[0039] For example, the converter 8 comprises an inverter, a transformer and a rectifier staged in this order between the battery 4 and the on-board network 6.

[0040] Conventionally, the inverter comprises switching elements, for example pairs of MOSFET transistors (from the English "Metal-Oxide-Semiconductor Field-Effect Transistor", or insulated gate field effect transistor) head to tail, capable of being controlled by pulse width modulation (in English "Pulse Width Modulation", or PWM) in order to generate an alternating voltage from a direct voltage.

[0041] Furthermore, the transformer is associated with a reduction ratio, and is adapted to convert an AC input voltage from the inverter into an AC output voltage such that the ratio between the amplitude of the input voltage and the amplitude of the output voltage is equal to the reduction ratio.

[0042] Finally, the rectifier is configured to transform the alternating output voltage of the transformer into a direct voltage.

[0043] Preferably, the converter 8 is bidirectional, that is to say it is adapted to transfer electrical energy from the high voltage network to the low voltage network, but also from the low voltage network to the high voltage network, depending on the way in which the converter 8 is controlled.

[0044] As mentioned previously, the control device 10 is connected to the converter 8, in order to control the operation of the converter 8.

[0045] More specifically, the control device 10 comprises a control module 15, a piloting module 16 and a safety module 17 which are separate from each other. An output of the control module 15 is connected to the input of the piloting module 16 for conveying a control signal ST. Furthermore, an output of the piloting module 16 is connected to the converter 8 for conveying a piloting signal SR. Finally, the safety module 17 is connected to the piloting module 16 to receive the piloting signal SR. Furthermore, an output of the safety module 17 is connected to the converter 8 for conveying a stop signal SA. An input of the safety module 17 is further connected to the voltage sensor 11 to receive the voltage measurement signal.

[0046] The control module 15 is configured to determine and generate the control signal ST in order to control the converter 8 in accordance with a corresponding operating instruction. In particular, the control signal ST is associated with an operating instruction of the converter 8 according to a first operating mode in which the converter 8 transfers electrical energy from the high-voltage network (i.e. from the battery 4) to the low-voltage network (i.e. to the on-board network 6).

[0047] Furthermore, and in a conventional manner, the control module 16 is configured to determine the control signal SR from the control signal ST received from the control module 15. Such a control signal SR comprises electrical signals adapted to control an operation of the converter 8, in particular to control the on or off state, as a function of time, of the switching elements of the converter 8.

[0048] Furthermore, the control module 15 is configured to monitor the evolution of the voltage measurement signal of the on-board network 6 delivered by the voltage sensor 11.

[0049] The control module 15 is also configured to, in the event of detection of an overvoltage at the level of the on-board network 6 while the converter 8 is controlled according to the first operating mode, send, to the converter 8, a control signal ST indicative of a command to suspend the transfer of electrical energy from the high voltage network to the low voltage network.

[0050] By "overvoltage at the on-board network", is meant, within the meaning of the present invention, a situation in which the current voltage of the on-board network 6 is higher than the second voltage, the difference between the voltage of the on-board network and the second voltage exceeding a predetermined maximum tolerable difference.

[0051] Such a suspension command aims to put the switching elements of the converter 8 in a blocked state (i.e. not passing).

[0052] The safety module 17, distinct from the control module 15 and the piloting module 16, is configured to monitor the evolution of the voltage measurement signal of the on-board network 6 delivered by the voltage sensor 11. The safety module 17 is also configured to, in the event of detection of an overvoltage at the level of the on-board network 6 while the converter 8 is piloted according to the first operating mode, verify compliance of the piloting signal SR delivered by the piloting module 16 with a suspension of the transfer of electrical energy from the battery 4 to the on-board network 6 by the converter 8 (i.e. verify that the piloting signal SR is indeed intended to interrupt said transfer of energy).For example, the safety module 17 is configured to calculate the control signal corresponding to such a suspension of the energy transfer, and to verify that the control signal SR received from the control module 16 is identical to the calculated control signal.

[0053] In particular, in an overvoltage situation at the level of the on-board network 6, the safety module 17 is configured to verify that the control signal SR actually delivered by the control module 16 is indeed capable of controlling the switching elements of the converter 8 to the blocked state.

[0054] Furthermore, the safety module 17 is configured to trigger, i.e. cause, the stopping of the converter 8 in the event of a discrepancy between the control signal SR and said suspension of the transfer of electrical energy (i.e. in the case where the control signal SR does not control the suspension of said transfer of electrical energy), so as to prevent any transfer of electrical energy between the converter 8 and the low voltage network.

[0055] For example, to trigger the shutdown of the converter 8, the safety module 17 is configured to interrupt a power supply to the switching elements of the converter 8, which inhibits any transfer of electrical energy between the converter 8 and the low voltage network.

[0056] Advantageously, the control device 10 is configured to, in response to the detection of an overvoltage at the on-board network if, and in the event of concordance between the control signal SR and said suspension of the transfer of electrical energy, control the converter 8 according to a second operating mode to cause the converter 8 to transfer electrical energy from the low voltage network to the high voltage network.

[0057] Such a characteristic is advantageous, insofar as its implementation contributes to absorbing the excess electrical energy present on the on-board network 6 and attributable to malfunctions external to the converter 8. Such a characteristic is also advantageous in that it makes it possible to eliminate the overvoltage in complete safety (after having eliminated the hypothesis of an internal fault).

[0058] Preferably, the control module 15 is also configured to monitor the evolution of the current measurement signal delivered by the current sensor 12.

[0059] In this case, in the event of detection of an overvoltage at the level of the on-board network 6 when the converter 8 is controlled according to the first operating mode, the control module 15 is also configured to determine, from the current measurement signal, a sign of the current flowing from the converter 8 to the low voltage network.

[0060] Furthermore, the control device 10 is configured to trigger the stopping of the converter 8 if it is determined that said current is positive, i.e. that it flows from the converter 8 to the on-board network 6.

[0061] Such a feature is advantageous, insofar as it provides additional safety in the event of an overvoltage which is not due to the converter 8. Operation

[0062] The operation of the control device 10 will now be described.

[0063] In normal operation, the control device 10 controls the converter 8 according to the first operating mode to transfer electrical energy from the battery 4 to the on-board network 6.

[0064] Furthermore, the control device 10, and in particular the control module 15, monitors the evolution of the voltage measurement signal delivered by the voltage sensor 11.

[0065] In response to an overvoltage at the level of the on-board network 6 occurring while the converter is controlled according to the first operating mode, the control module 15 sends, to the converter 8, and via the control module 16, the command to suspend the transfer of electrical energy from the battery 4 to the on-board network 6.

[0066] Furthermore, the safety module 17 verifies that the control signal SR delivered by the control module 16 is consistent with a suspension of the transfer of electrical energy from the battery 4 to the on-board network 6 by the converter 8.

[0067] In the event of a discrepancy between the control signal SR and said suspension of the transfer of electrical energy, the safety module 17 triggers the shutdown of the converter 8.

[0068] Of course, the invention is not limited to the examples which have just been described.

Claims

Claims

1. Control device (10) for a converter (8) intended to be installed on board a motor vehicle and arranged in use between a high voltage network (4) of the motor vehicle, associated with a first direct voltage, and a low voltage network (6) of the motor vehicle, associated with a second direct voltage lower than the first voltage, the control device (10) comprising a control module (15), a pilot module (16) and a safety module (17): • the control module (15) being configured to deliver a control signal (ST) associated with an operating instruction of the converter (8), in particular an operation according to a first operating mode in which the converter (8) transfers electrical energy from the high voltage network (4) to the low voltage network (6), • the control module (16) being configured to apply, to the converter (8), a control signal (SR) depending on the control signal (ST), so as to control the converter (8) in accordance with the operating instruction, • the control module (15) being, in addition, configured to, in response to the detection of an overvoltage at the low voltage network (6) during the first operating mode, deliver a signal (ST) for controlling a suspension of the transfer of electrical energy from the high voltage network (4) to the low voltage network (6) by the converter (8); • the safety module (17) being configured to, in response to the detection of an overvoltage at the low voltage network (6) during the first operating mode: • check compliance of the control signal (SR) with a suspension of the transfer of electrical energy from the high voltage network (4) to the low voltage network (6) by the converter (8); and • trigger a shutdown of the converter (8) in the event of a discrepancy between the control signal (SR) and said suspension of the transfer of electrical energy.

2. A control device (10) according to claim 1, further comprising a voltage sensor (11) configured to output a voltage measurement signal indicative of a voltage of the low voltage network (6).

3. Control device (10) according to claim 1 or 2, also configured to, in the event of detection of an overvoltage at the low voltage network (6) during the first operating mode: • determine a sign of a current flowing from the converter (8) to the low voltage network (6); and • trigger the stopping of the converter (8) if said current is positive.

4. Control device (10) according to any one of claims 1 to 3, also configured to, in response to the detection of an overvoltage at the low voltage network (6) during the first operating mode and in the event of concordance between the control signal (SR) and said suspension of the transfer of electrical energy, control the converter (8) according to a second operating mode to cause the converter (8) to transfer electrical energy from the low voltage network (6) to the high voltage network (4).

5. Vehicle (2) comprising a control device (10) according to any one of claims 1 to 4, a battery forming the high voltage network (4), an on-board network forming the low voltage network (6), and a converter (8) connected between the battery and the on-board network, the control device (10) being connected to the converter (8) to control the operation of the converter (8).

6. Method for controlling a converter (8) on board a motor vehicle and arranged between a high voltage network (4) of the motor vehicle, associated with a first DC voltage, and a low voltage network (6) of the motor vehicle, associated with a second DC voltage lower than the first voltage, the control method comprising the steps: • supplying at the output, by a control module (15), a control signal (ST) associated with an operating instruction of the converter (8), in particular according to a first operating mode in which the converter (8) transfers electrical energy from the high voltage network (4) to the low voltage network (6); and • application, to the converter (8), by a control module (16), of a control signal (SR) depending on the control signal (ST), to control the converter (8) in accordance with the operating instruction, the control method further comprising, in response to the detection of an overvoltage at the low voltage network (6) during the first operating mode, the steps: • supply at the output, by the control module (15), of a signal (ST) for controlling a suspension of the transfer of electrical energy from the high voltage network (4) to the low voltage network (6) by the converter (8); • verification, by a safety module (17) separate from the control module (15) and the pilot module (16) of conformity of the pilot signal (SR) with a suspension of the transfer of electrical energy from the high voltage network (4) to the low voltage network (6) by the converter (8); and • triggering, by the safety module (17), of a shutdown of the converter (8) in the event of a discrepancy between the control signal (SR) and said suspension of the transfer of electrical energy.

7. Method according to claim 6, also comprising, in the event of detection of an overvoltage at the low voltage network (6) when the converter (8) is controlled according to the first operating mode, the steps: • determination of a sign of a current flowing from the converter (8) to the low voltage network (6); and • triggering the shutdown of the converter (8) if said current is positive.

8. Method according to claim 6 or 7, further comprising, in the event of concordance between the control signal (ST) and said suspension of the transfer of electrical energy, a control of the converter (8) according to a second operating mode to cause the converter (8) to transfer electrical energy from the low voltage network (6) to

9. the high voltage network (4). Control method according to any one of claims 6 to 8, in which the high voltage network (4) is a battery on board a vehicle (2), and in which the low voltage network (6) is an on-board network of the vehicle (2).

10. A computer program comprising executable instructions which, when executed by a computer, implement the steps of the method according to any one of claims 6 to 8.

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