FR3123126A1 - METHOD FOR FAILURE SUPERVISION OF AN ELECTRICAL INSULATION DEVICE AND TESTING OF A LOW VOLTAGE ELECTRICAL STORAGE IN AN ELECTRIFIED VEHICLE - Google Patents

Abstract

The method is implemented in an electrified vehicle of the type having an on-board electrical network (RDB) comprising an electrical store (BT_BAT), an electrical generator (C_DC/DC) and an electrical isolation and test device (DEx) associated with the storer to electrically isolate the storer during a test thereof and electrically connect the storer to the generator at the end of the test, the method providing supervision of a failure of the electrical isolation and test device to be connected the store to the generator at the end of the test. In accordance with the invention, the method comprises the steps of a) detecting (BF1, DCS) a failure of the electrical insulation and test device from at least one piece of information (BIC, DIAG) supplied by the latter and vehicle traffic information (VRS); and b) reduce (BF2, LP_ESP/DAE, REC) the electrical consumption of the on-board electrical network when a failure is detected in step a). Figure 2

Description

METHOD FOR FAILURE SUPERVISION OF AN ELECTRICAL INSULATION DEVICE AND TESTING OF A LOW VOLTAGE ELECTRICAL STORAGE IN AN ELECTRIFIED VEHICLE

The invention generally relates to the monitoring of the power supply of so-called security devices in a vehicle. More particularly, the invention relates to a method and a system for supervising the failure of an electrical insulation and test device associated with a low-voltage electrical energy store in an electrified vehicle, in particular an electric vehicle.

In latest-generation motor vehicles, the electrical energy store of the on-board electrical power supply network, typically a 12 Volt battery, is tested periodically while the vehicle is in motion in order to ascertain its ability to meet the safety needs of the vehicle. The information on the ability to meet the safety needs of the vehicle of the electrical energy store is used by the vehicle's energy management strategies. In particular, in electric vehicles, it is known to use an electrical isolation device, or electrical circuit breaker, to electrically isolate the low-voltage electrical energy store from its electrical generator and from the on-board electrical power supply network during the storer test.

To the , by way of illustration, an example of the architecture of an electric vehicle VE is shown schematically. The vehicle VE comprises a high voltage electrical energy storer HT_BAT and a low voltage electrical energy storer BT_BAT.

The HT_BAT high voltage electrical energy storage device is dedicated to vehicle traction. The HT_BAT storer is connected to an on-board electric charger CHG and supplies an electric traction machine MEL through an electric converter C_AC/DC of the reversible “AC/DC” type. The reversibility of the C_AC/DC electrical converter allows energy recovery during vehicle braking phases.

The low voltage electrical energy storer BT_BAT is connected to a C_DC/DC electrical converter of the "DC/DC" type and to the low voltage on-board electrical power supply network RDB through an electrical isolation and storage test device OF. The storer BT_BAT is charged by the electrical converter C_DC/DC acting as an electrical generator of the on-board electrical network RDB. The C_DC/DC electrical converter is supplied with electrical energy by the high voltage electrical energy storer HT_BAT.

The storage device electrical isolation and test device DE typically comprises electronic power switches, such as “MOSFET” type transistors, and allows electrical connection/disconnection of the storage device BT_BAT with respect to the converter C_DC/DC and to the electrical network edge RGB. The storer BT_BAT can thus be electrically isolated from the converter C_DC/DC and from the on-board electrical network RDB in order to carry out tests, such as a periodic test while the vehicle is running to find out the capacity of the storer to meet the security needs of the vehicle.

The RDB on-board electrical supply network supplies various so-called safety devices such as the electronic trajectory correction device, known as the "ESP" corrector for "Electronic Stability Program" in English, the electric power steering "DAE", the braking system electric SFE and others. During so-called safe maneuvers, such as emergency braking, collision avoidance or others, a failure of the power supply of the aforementioned safety devices can lead to the occurrence of a potentially dangerous event of level "D". in the standard classification "ASIL" (for "Automotive Security Integrity Level"). In the event of failure of the electrical converter C_DC/DC, which acts as an electrical generator for the on-board electrical network RDB, it is the storer BT_BAT which guarantees the permanence of the electrical supply in the on-board electrical network RDB. It is therefore important to ensure that the storer BT_BAT is systematically reconnected to the on-board electrical network RDB by the device DE after each disconnection of the storer.

From the documents CN110346682A and JP2014192966A, devices are known capable of detecting an absence of connection between a "DC/DC" electric converter and a low-voltage electric energy storer in a vehicle, such as an electric vehicle, comprising a low-voltage electrical network and a low-voltage electrical network. In the CN110346682A device, it is provided for the activation of an alarm when a connection anomaly is detected.

It is desirable to provide a solution for supervising the failure of an electrical insulation and storage test device associated with a low-voltage electrical energy storage device in an electrified vehicle, in particular in order to optimize the consumption of a the vehicle's low-voltage on-board power supply network and, in particular, the consumption of devices contributing to the safety of the vehicle and its passengers in the event of emergency manoeuvres.

According to a first aspect, the invention relates to a method implemented in an electrified vehicle of the type having a low-voltage on-board electrical power supply network comprising an electrical energy store, an electrical generator and an electrical isolation device and associated with the electric energy storer for electrically isolating the electric energy storer during a test thereof and electrically connecting the electric energy storer to the electric generator at the end of the test, the method providing supervision a failure of the electrical isolation and test device to connect the electrical energy store to the electrical generator at the end of the test. In accordance with the invention, the method comprises the steps of a) detecting a failure of the electrical insulation and test device from at least one piece of information provided by the electrical insulation and test device and rolling information of the vehicle ; and b) reduce the power consumption of the low voltage on-board power supply network when a fault is detected in step a).

According to one particular characteristic, step b) comprises a reduction in the electrical consumption of so-called safety devices of the vehicle powered by the low-voltage on-board electrical power supply network and a load shedding of non-priority consumers from the on-board electrical power supply network low tension.

According to another particular characteristic, in step a), said at least one piece of information provided by the electrical isolation and test device comprises a first state piece of information indicating the capacity or the inability of the electrical isolation device and to be switched and a second state cue representative of a time elapsed since the start of the electrical isolation of the electrical energy store provided by the electrical isolation and test device for the test.

According to yet another particular characteristic, the method also comprises a step c) of alerting the driver of the vehicle of the detection of a failure through the vehicle's man-machine interface means.

According to yet another particular characteristic, the method also comprises a step d) of transmitting data on the faults detected to at least one computer server through the vehicle's wireless connectivity means and a wireless data communication network.

The invention also relates to an on-board system in an electrified vehicle of the type having a low-voltage on-board electrical power supply network comprising an electrical energy store, an electrical generator and an electrical isolation and test device associated with the electrical energy store. electrical energy to electrically isolate the electrical energy store during a test thereof and electrically connect the electrical energy store to the electrical generator at the end of the test, the system providing supervision of a failure of the device electrical isolation and test to connect the electrical energy store to the electrical generator at the end of the test. In accordance with the invention, the system comprises a computer having a memory storing program instructions for implementing the method as briefly described above.

The invention also relates to an electrified vehicle comprising an on-board system as described above. According to a particular embodiment of the electrified vehicle, the electrical generator of the vehicle's low voltage on-board electrical power supply network is a DC/DC type electrical converter.

Other advantages and characteristics of the present invention will appear more clearly on reading the detailed description below of several particular embodiments of the invention, with reference to the appended drawings, in which:

The is a block diagram showing schematically an electrical architecture of an electric vehicle.

The is a block diagram of an on-board system for implementing the method according to the invention, as well as the hardware environment of the system in the vehicle.

The is a first flowchart relating to a functional block for storing failure detection included in the method according to the invention.

The is a second flowchart relating to the storer failure detection functional block included in the method according to the invention.

The is another flowchart relating to a functional block for reducing electrical consumption in the method according to the invention.

With reference to Figs.2 to 5, a particular embodiment of the method according to the invention is now described. In this exemplary embodiment, the method is implemented in an SE system of the invention on board an electric vehicle such as the electric vehicle VE described above in relation to the .

With particular reference to the , the method according to the invention is implemented in a hardware environment comprising in particular a low-voltage on-board electrical power supply network RDB, an electrical converter C_DC/DC of the “DC/DC” type and a low electrical energy storer BT_BAT voltage which are similar to those described above with reference to the . An electrical insulation and storer test device, marked DEx, is also associated with the storer BT_BAT and is here of a type comprising internal self-test means to determine its operating state and communicate information to the outside. BIC and DIAG status. As will appear clearly subsequently, the BIC and DIAG status information delivered by the device DEx are used by the method according to the invention.

As seen at , the device DEx here comprises electrical connections with the storer BT_BAT, a test discharge resistor RD, the electrical converter C_DC/DC and the on-board electrical network RDB.

The device DEx can assume two different switching states, namely a first switching state corresponding to an operational operating configuration of the storer BT_BAT and a second switching state, of short duration, corresponding to a test configuration of the storer BT_BAT.

In the first switching state, the device DEx maintains the storer BT_BAT connected to the electrical converter C_DC/DC and to the on-board electrical network RDB, and maintains the test discharge resistor RD disconnected and electrically isolated.

In the second switching state, the device DEx maintains, for a short test duration, the storer BT_BAT disconnected from the on-board electrical network RDB and from the electrical converter C_DC/DC and connects the test discharge resistor RD to the storer BT_BAT for a solicitation of the latter by one or more successive discharge current surges, according to an activation profile.

The BIC status information delivered by the DEx device indicates, at the moment considered, the ability or the inability of the DEx device to fully perform, or not, internal power switching operations by means of its electronic switches of power, in other words, its ability or inability to switch between the aforementioned first and second switching states without failure. Thus, for example, when the electronic power switches are “MOSFET” type transistors, their ability to switch or not can be determined from leakage current measurements.

The DIAG status information delivered by the DEx device indicates, at the instant considered, whether or not the DEx device is in the switching state corresponding to the test of the storer BT_BAT, that is to say, if it is or is not in the aforementioned second switching state. The BT_BAT storer test has a predefined duration, typically around one second (1s). An anomaly is detected when the duration of permanence of the DEx device in the second switching state, determined using the DIAG state information, is greater than a predefined test duration threshold, for example one and a half seconds ( 1.5 sec).

When testing the BT_BAT storer, requesting it by one or more successive discharge current inrushes is a means of testing the state of health of the storer. Characteristic parameters of the storer BT_BAT, such as its internal resistance, minimum voltages reached during discharge current inrushes and others, can thus be evaluated. To guarantee the reliability of the current and voltage measurements in the BT_BAT storer during the test, necessary for the evaluation of the characteristic parameters of the latter, the electrical insulation of the BT_BAT storer with respect to the C_DC/DC voltage converter and to the RDB on-board electrical network must be ensured by the DEx device. Indeed, it is necessary that the current variations, and the consecutive voltage variations, which are imposed on the storer BT_BAT during the test are only linked to the test and not to the voltage converter C_DC/DC connected to the on-board electrical network RGB.

Knowledge of the state of health of the storer BT_BAT, thanks to the result of the test carried out, makes it possible to assess a level of exposure to a risk of failure of the storer. Thus, the management of the RDB on-board electrical network can be adapted according to the assessment of this level of exposure, for example, by reducing the overall electrical consumption, and/or by alerting the driver via dedicated human-machine interfaces. , such as indicator lights and the like.

The method according to the invention, for its part, makes it possible to detect a life situation in which the DEx device, after having switched to electrically isolate the storer BT_BAT and to carry out the test thereof, remains blocked while the test is completed. , now the storer BT_BAT is electrically isolated from the on-board electrical network RDB and from the electrical converter C_DC/DC. Such a living situation implies, as indicated above, a risk to the safety of the vehicle and its passengers in the event of an emergency maneuver, as well as a lack of recharging or maintaining the load of the storage device BT_BAT having as a potential consequence an inability to restart the vehicle the next time it is driven due to the storage facility's ability to meet the safety needs of the degraded vehicle. The method according to the invention provides, in this life situation, to reduce the electrical consumption of the on-board electrical network RDB and, in particular, that of the safety consumers, to alert the driver, and to communicate failure data to a or several remote computer servers via the vehicle's wireless connectivity means. The failure data is used by the computer server, in particular for the purpose of statistical analysis on the frequency of occurrence of defects or for other analyses, for example, a cross-analysis with other data.

Always referring to the , the method according to the invention is implemented by means of an embedded software module ESW implanted in a memory MEM of a computer ECU of the vehicle. The ECU computer is for example a multifunction computer of the vehicle which hosts various vehicle control strategies. In the present invention, the ECU computer cooperates, under the supervision of the ESW software module, with other computers of the vehicle for the activation in particular of one or more degraded modes for reducing electrical consumption, the generation of alerts to through man-machine interfaces and the transmission of data to remote computer servers.

The software module ESW authorizes the implementation of the method according to the invention by the execution of program code instructions by a processor (not shown) of the computer ECU.

As seen at , the software module ESW essentially comprises four function blocks BF1 to BF4.

The functional block BF1 essentially has the function of detecting a connection fault of the storer BT_BAT to its electrical generator, here the electrical converter C_DC/DC, or to another part of the on-board electrical network RDB, a connection fault occurring after a test of the storekeeper.

Functional block BF1 receives the aforementioned BIC and DIAG status information as input, as well as VRS status information indicating whether or not the vehicle is in a driving situation. The VRS status information switches to an active state VRS=“1” indicating a driving situation as soon as the vehicle is started by the driver who, for this purpose, presses a start button DEM or operates an ignition key. The functional block BF1, from the BIC, DIAG and VRS status information, decides whether the storer BT_BAT is in a fault life situation which requires to be processed by the process of the method of the invention. Functional block BF1 outputs storer connection fault information DCS which indicates the decision of functional block BF1, with DCS = "1" indicating the presence of a storer connection fault BT_BAT and DCS = "0" indicating the absence of a connection fault thereof. The DCS store connection fault information is supplied as input to the functional blocks BF2 to BF4.

The processing carried out by the BF1 functional block is illustrated by the flowcharts of Figs.3 and 4. The flowchart of the represents logical conditions which must be satisfied for the detection, with DCS=“1”, of an effective connection fault of the storer BT_BAT. The flowchart of the represents logical conditions which must be satisfied for the detection, with DCS=“0”, of an absence of connection fault of the storer BT_BAT.

In the flowchart of the relating to the detection of an effective connection fault of the storer BT_BAT, three condition detection loops DL1, DL2 and DL3 scrutinize the states of the information VRS, BIC and DIAG, respectively.

The state detection loop DL1, processing the VRS information, activates an output OK = "1" when the VRS information, with VRS = "1", indicates that the vehicle is in a driving situation, and activates an output of waiting loop NOK=“1” in the opposite case, that is to say, when the VRS information, with VRS=“0”, indicates that the vehicle is not in a rolling situation.

The DL2 state detection loop, processing the BIC information, activates an output OK = "1" when the BIC information, with BIC = "0", indicates that the DEx device is not able to switch normally , possibly due to a failure of its electronic power switches, and activates a waiting loop output NOK = "1" in the opposite case, that is to say, when the BIC information, with BIC = “1”, indicates that the DEx device is able to switch normally.

The state detection loop DL3, processing the DIAG information, activates an output OK = "1" when the DIAG information, with DIAG = "1" which persists for a duration DD greater than a test duration threshold of DDtest storer, indicates an anomaly in the switching state of the DEx device. Loop DL3 activates a waiting loop output NOK = "1" otherwise, i.e. when the DIAG information, with the duration DD of DIAG = "1" less than DDtest, indicates that the DEx device has returned to a correct switching state after the BT_BAT storer test.

As shown at , the three OK outputs of the condition detection loops DL1, DL2 and DL3 are supplied as input to an “AND” logic function, FL1. When the three conditions VRS = "1", BIC = "0" and DIAG = "1" with DD>DDtest are satisfied, the three OK outputs are active, with OK = "1", and the connection fault information DCS storer mode is enabled, with DCS = "1".

In the flowchart of the relating to the detection of an absence of connection fault of the storer BT_BAT, two condition detection loops DL4 and DL5 scrutinize the states of the information VRS and BIC, respectively.

The DL4 state detection loop, processing the VRS information, activates an output OK = "1" when the vehicle is started, when the VRS information, changing from VRS = "0" to VRS = "1", indicates that the vehicle is now in driving condition. Otherwise, when the VRS information, with VRS = "0", indicates that the vehicle is not in a driving situation, it is the waiting loop output NOK = "1" which is activated.

The DL5 state detection loop, processing the BIC information, activates an output OK = "1" when the BIC information, with BIC = "1", indicates that the DEx device is able to switch normally, and activates a waiting loop output NOK = "1" in the opposite case, that is to say, when the BIC information, with BIC = "0", indicates that the DEx device is not able to switch normally, possibly due to a failure of its electronic power switches.

As shown at , the two OK outputs of the condition detection loops DL4 and DL5 are supplied as input to a “NAND” logic function, FL2. When the two conditions VRS = "1" and BIC = "1", the two OK outputs are active, with OK = "1", and the DCS store connection fault information is inactive, with DCS = "0" .

With particular reference to the , in the life situation where the information DCS = "1" indicates the occurrence of an effective connection fault of the storer BT_BAT, the functional blocks BF2, BF3 and BF4 are activated and trip respectively, as indicated above in the description, a reduction in electrical consumption by means of LP_ESP/DAE and RCE commands, driver alerting via man-machine interface means such as V_BT_BAT, V_STOP and V_SERVICE indicator lights, and transmission of D_DEF failure data to one or more remote computer servers.

Also with reference to the , when the DCS = "1" information is validated by the OK output of the DL6 state detection loop, the BF2 functional block triggers a degraded operating mode aimed at reducing electrical consumption by activating, on the one hand, a strategy for the overall reduction of electrical consumption of the on-board electrical network RDB by means of the command RCE = "1" and, on the other hand, a strategy for limiting the electrical power consumed by safe consumers, such as the corrector "ESP" and the electric power steering DAE, using the command LP_ESP/DAE = "1". As long as the DCS = "0" information, the NOK output of the DL6 state detection loop is active and invalid, with the RCE = "0" and LP_ESP/DAE = "0" commands, the application of the strategies aforementioned.

In the present invention, the reduction in the electrical consumption of the on-board electrical network RDB, with RCE = "1", makes it possible to prioritize the electrical power available to the safe electrical consumers, such as the "ESP" corrector and the electric power steering DAE , in particular in the event that their activation is necessary for an emergency maneuver. Thus, this reduction in electrical consumption may be obtained by the load shedding of electrical consumers of the vehicle identified as being non-priority. These electrical consumers are, for example, consumers of thermal comfort, such as heated seats, neck heaters and the like.

Limiting the electrical power consumed by safety electrical consumers, such as the "ESP" corrector and the DAE electric power steering, reduces the performance of these, but on the other hand offers the advantage of reducing the risk of non-operation of those -this by preventing a collapse of the voltage of the RDB on-board electrical network in the event of an emergency maneuver. Thus, the electrical power allocated to secure electrical consumers may be reduced, for example, to 60% of their nominal operating power.

In parallel with the activation by the functional block BF2 of the consumption reduction strategies, the functional block BF3, with the information DCS = “1”, triggers a driver alert via man-machine interface means. As mentioned above, these man-machine interface means are, for example, a battery indicator light V_BT_BAT, a stop indicator light V_STOP and a service indicator light V_SERVICE present on the dashboard of the vehicle. When the DCS information = "1", the BF3 function block activates the V_BT_BAT LED and the V_STOP LED. The V_BT_BAT warning light signals a problem on the BT_BAT storage unit and the V_STOP warning light reinforces the seriousness of this problem by indicating that it is likely to cause the vehicle to stop. The V_SERVICE warning light remains off in this life situation, but may be activated later, for example if the problem persists, to prompt the driver to call an after-sales repair service.

Concerning the transmission of failure data D_DEF provided by the functional block BF4, data may be transmitted to a remote computer server after each occurrence of a fault, or else be transmitted periodically, for example in the form of statistical data established locally by the function block BF4. Thus, these D_DEF data are transmitted via the wireless connectivity means of the vehicle and a wireless data communication network such as a cellular mobile telephone network of the “LTE” type, for “Long Term Evolution” in English. Typically, mass analyses, also known as “Big Data analytics” in English, will be carried out on these D_DEF failure data, possibly crossing them with data of other types. The lessons learned from these analyzes can be used by the car manufacturer's research and development teams, in particular for improvements in the design of the vehicle's low-voltage architecture and to help deal with any technical crises in after-sales. occurring on vehicles in the rolling stock.

The present invention provides a low-cost solution for improving the security of the low-voltage on-board power supply network of electrified vehicles. In addition, the proposed solution is adapted to meet the needs and architectural constraints of different types of electrified vehicles, in particular all-electric, hybrid and plug-in hybrid vehicles.

The invention is not limited to the particular embodiments which have been described here by way of example. The person skilled in the art, depending on the applications of the invention, may make various modifications and variants falling within the scope of protection of the invention.

Claims (8)

Method implemented in an electrified vehicle (VE) of the type having a low voltage on-board electrical power supply network (RDB) comprising an electrical energy store (BT_BAT), an electrical generator (C_DC/DC) and a electrical isolation and test (DEx) associated with said electrical energy storer (BT_BAT) to electrically isolate said electrical energy storer (BT_BAT) during a test thereof and electrically connect said electrical energy storer ( BT_BAT) to said electrical generator (C_DC/DC) at the end of said test, the method ensuring supervision of a failure of said electrical isolation and test device (DEx) to connect said electrical energy store (BT_BAT) to said generator (C_DC/DC) at the end of said test, characterized in that it comprises the steps of a) detecting (BF1, DCS) a said failure of said electrical isolation and test device (DEx) from at least one piece of information (BIC, DIAG) provided by led it electrical isolation and test device (DEx) and driving information (VRS) of said vehicle; and b) reducing (BF2, LP_ESP/DAE, REC) the electrical consumption of said low voltage on-board electrical power supply network (BT_BAT) when said failure is detected in step a). Method according to Claim 1, characterized in that the said step b) comprises a reduction in the electrical consumption (LP_ESP/DAE) of the so-called security devices of the said vehicle powered by the said low-voltage on-board electrical power supply network (RDB) and load shedding (RCE) of non-priority consumers of said low-voltage on-board power supply network (RDB). Method according to claim 1 or 2, characterized in that, in said step a), said at least one piece of information provided by said electrical isolation and test device (DEx) comprises a first state piece of information (BIC) indicating the ability or inability of said electrical isolation and test device (DEx) to switch and second status information (DIAG) representing an elapsed time (DD) since the start of the electrical isolation of said electrical energy store (BT_BAT) provided by said electrical isolation and test device (DEx) for said test. Method according to any one of Claims 1 to 3, characterized in that it also comprises a step c) of alerting (BF3, V_BT_BAT, V_STOP, V_SERVICE) the driver of the said vehicle of the detection of a said failure through man-machine interface means of said vehicle. Method according to any one of Claims 1 to 4, characterized in that it also comprises a step d) of transmitting (BF4) data on the detected failures (D_DEF) to at least one computer server through connectivity means said vehicle and a wireless data communication network. System (SE) on board an electrified vehicle (EV) of the type having a low voltage on-board electrical power supply network comprising an electrical energy store (BT_BAT), an electrical generator (C_DC/DC) and an isolation device electrical and test (DEx) associated with said electrical energy storer (BT_BAT) to electrically isolate said electrical energy storer (BT_BAT) during a test thereof and electrically connect said electrical energy storer (BT_BAT) to said electrical generator (C_DC/DC) at the end of said test, the system providing supervision of a failure of said electrical isolation and test device (DEx) to connect said electrical energy store (BT_BAT) to said electrical generator ( C_DC/DC) at the end of said test, characterized in that it comprises a computer (ECU) having a memory (MEM) storing program instructions for implementing the method according to any one of Claims 1 to 5 . Electrified vehicle comprising an on-board system (ES) according to claim 6. Electrified vehicle according to claim 7, in which said electrical generator of said low-voltage on-board electrical power supply network (RDB) of the vehicle is an electrical converter of the “DC/DC” type (C_DC/DC).