Method for ending charging and diagnosing switches of a charging system for an electric or hybrid vehicle

Abstract

The present invention relates to a method for ending charging and diagnosing switches (13, 14, 15, 16) of a charging system (32) of an electric vehicle (30) comprising a voltage booster (5) having a capacitor (6) connected at the input terminals thereof, and two switches (13, 14) each connected to a separate terminal of a charging socket (8), the method comprising a command to open the switches (13, 14, 15, 16), and if the voltage (VDC) at the terminals of the socket (8) is greater than a safety voltage, and the voltage downstream and upstream of the switches (13, 14, 15, 16) is similar, when the load has used the voltage booster (5) and in the absence of information on the closing of a charging flap, the method comprises discharging the capacitor (6) and then comparing the voltage (VDC) at the terminals of the socket (8) with the voltage (VB) downstream of the switches (13, 14, 15, 16).

Description

[0001] DESCRIPTION

[0002] Title of the invention ■ Method for ending charging and diagnosing switches in a charging system for an electric or hybrid vehicle

[0003] The present invention relates to the fields of automotive and electrical engineering, and more specifically concerns a method for ending charging and diagnosing power switches in a charging system of an electric or hybrid vehicle.

[0004] An electric or hybrid vehicle generally has a high-voltage traction battery, which is discharged to power, via an inverter, an alternating current electric traction motor of the vehicle. The vehicle therefore requires a traction battery charging system. Such a system recharges the traction battery by recovering energy when the vehicle brakes, or from a charging station external to the vehicle. Direct current charging stations allow very rapid charging of the traction battery, by delivering a charging voltage higher than the voltage of the traction battery, which is of the order of several hundred Volts.

[0005] To enable such rapid charging, the charging system must include power switches to electrically connect the traction battery to a DC charging terminal. The very high current supplied by such a charging terminal, which can reach several hundred amperes, can damage these switches. Particularly if these switches are mechanical relays, too high a current flowing through them can weld them to their terminals, making them always conductive. If they are MOSFET (Metal Oxide Semiconductor Field Effect Transistor) type switches, too high a current flowing through them can also damage their substrates so that they always conductive. In both cases, the power switches are considered to be "stuck".In fact, in this application, "sticking" means the fact that the switch in question is kept welded to its terminals if it is a mechanical relay, or deterioration of the switch keeping it constantly on if it is a MOSFET transistor.

[0006] In order to ensure the electrical safety of a vehicle user at the start or end of charging, and to prevent a subsequent malfunction of the vehicle due to such deterioration of the power switches, the standard provides that a vehicle computer can perform a diagnosis of power switches located between a vehicle charging socket and the vehicle's traction battery, these power switches being located upstream of power switches connecting the vehicle's traction battery to the inverter. To perform this diagnosis, the vehicle communicates with the charging station. When the latter receives an indication of the start of such a diagnostic process from the vehicle, it must open its own power switches, i.e. cancel its charging voltage and not deliver any charging current to the vehicle.

[0007] Furthermore, some vehicles now have traction batteries with a maximum no-load voltage well above the maximum voltage level available at the output of charging terminals typically encountered delivering a maximum voltage of less than 500V (Volts), so that in such a vehicle, the charging socket for direct current charging is no longer directly connected to the vehicle's traction battery, but is connected to the input of a voltage booster stage which is itself connected to the output of the traction battery.

[0008] In this case, at least some of the power switches that the vehicle needs to diagnose are located between the vehicle's charging socket and the input of the voltage boost stage, always upstream of the inverter.

[0009] It should be noted that the terms "upstream" or "downstream" in this application refer to the relative position of electrical components or assemblies with respect to the direction of the current leaving the terminal and heading towards the traction battery. Thus, a first component is upstream of a second component if the current leaving the terminal first passes through the first component and then the second component before entering the traction battery. Due to the positioning of these power switches to be diagnosed, when a fairly high voltage persists between the plugs of the charging socket while the latter is still connected to the terminal, it is difficult for the vehicle's computer to distinguish between:

[0010] - on the one hand, a problem which would be due both to a sticking of the power switches of the charging terminal, and to a sticking of the power switches connecting the vehicle's traction battery to its inverter, the battery voltage level being substantially the same as that delivered by the charging terminal,

[0011] - and on the other hand a problem which would be due to a sticking only of the power switches to be diagnosed.

[0012] In both cases it is dangerous for the vehicle user to disconnect the charging cable.

[0013] There is therefore a need to ensure the safety of a user of an electric or hybrid vehicle by correctly diagnosing the proper functioning or malfunction of power switches located downstream of a vehicle charging socket and upstream of power switches connecting a traction battery of the vehicle to a vehicle inverter, these switches being able to also be located upstream of an input of a vehicle voltage booster depending on the configuration of a vehicle charging system.

[0014] The present invention aims to remedy at least in part the drawbacks of the prior art by providing a method for ending charging and diagnosing power switches of a charging system of an electric or hybrid vehicle equipped with a voltage booster, which makes it possible to diagnose a sticking for each of the switches used to charge a battery of the vehicle via the voltage booster stage, by using the latter cleverly, and which makes it possible to reinforce the electrical safety of the user.

[0015] To this end, the invention proposes a method for ending charging and diagnosing power switches of a charging system of an electric or hybrid vehicle, the vehicle comprising a traction battery and an inverter capable of powering an electric motor of the vehicle, the charging system comprising at least:

[0016] - a switch, called a positive battery switch, connected by a first of its terminals to a positive terminal of the traction battery and by a second of its terminals to a positive input terminal of the inverter, and

[0017] - a switch, called a negative battery switch, connected by a first of its terminals to a negative terminal of the traction battery and by a second of its terminals to a negative input terminal of the inverter,

[0018] - a voltage booster stage comprising at least one capacitor, a positive terminal of which is connected to a positive input terminal of the voltage booster stage and a negative terminal of which is connected to a negative input terminal of the voltage booster stage,

[0019] - two switches used during charging, called switches to be tested, a first switch to be tested being connected by a first of its terminals to a positive terminal of the charging socket and by a second of its terminals to the positive input terminal of the voltage booster stage when the charging has used the voltage booster stage, a second switch to be tested being connected by a first of its terminals to a negative terminal of the charging socket and by a second of its terminals to the second terminal of the negative battery switch, the method comprising:

[0020] - a step of controlling the opening of the switches to be tested,

[0021] - a first comparison step, between on the one hand a voltage at the terminals of the charging socket and on the other hand a predefined safety voltage, the method further comprising, when the voltage at the terminals of the charging socket is higher than the predefined safety voltage:

[0022] - a second comparison step, between on the one hand the voltage at the terminals of the charging socket, and on the other hand a voltage between the second terminals of the switches to be tested, the method being characterized in that, when the load has used the voltage booster stage, when a difference between the voltages compared during the second comparison step is less than a predefined voltage difference, and in the absence of information on the closing of a charging hatch of the vehicle used to access the charging socket, the method further comprises a step of discharging the capacity then a third comparison step, between on the one hand the voltage at the terminals of the charging socket and on the other hand the voltage between the second terminals of the switches to be tested.

[0023] It should be noted that the voltages compared, in this method according to the invention, are positive voltages or in absolute value, unless otherwise stated. In addition, the steps of the method are mentioned in their order of execution. These steps are implemented at least in part by a computer of the vehicle, at the end of a direct current charge of the traction battery, the charge having used a charging socket of the vehicle connected to a direct current charging terminal via a charging cable.

[0024] It should also be noted that the connections disclosed in this application concerning the terminals of the switches are understood as direct connections, that is to say made of components of zero or almost zero resistance having only a conductive function, except possibly having a fuse function or additional switch not forming the subject of the invention. These switches are power switches, for example mechanical relays or MOSFET transistors (for the English "Metal Oxide Semiconductor Field Effect Transistor"). The first and second terminals of each switch correspond to terminals of this switch distinct from one another.

[0025] Furthermore, in this patent application, unless otherwise stated, an input or output connection of a functional assembly such as the inverter or the voltage booster stage is understood to mean a connection to the terminals of this input or respectively this output, i.e. a parallel connection to this input or respectively this output. Here the inverter is in particular connected at the output (in relation to its inverter function) to the phase connections of the electric motor of the vehicle.

[0026] In this application also, the traction battery is understood as a battery powering the inverter and the electric motor when the vehicle is running, unlike a vehicle service battery powering a low-voltage electrical network of the vehicle (for example 14V) to which various consumers are connected, including a main computer of the vehicle. The traction battery can therefore also be understood as a propulsion battery depending on the electric motor used. Unless otherwise stated, the battery referred to in this application is the traction battery of the vehicle. Similarly, the motor and the inverter in this patent application refer to an electric traction or propulsion motor and to a traction or propulsion inverter of the vehicle, in the absence of any indication to the contrary. Finally, the terms "charge" or "recharge" are considered equivalent in this application.

[0027] In the third comparison step of the method according to the invention, the charging used the vehicle's voltage booster, connected at the input to the charging terminal and at the output to the terminals of the traction battery. By "using the voltage booster" in this application, it is meant that the charging current passes through this voltage booster, which is systematically the case if the charging system does not have direct connection means between the charging terminal and the traction battery.

[0028] By discharging the capacitor before this third comparison step, the voltage across the charging socket during the third comparison step must be different from that between the second terminals of the switches to be tested if these are not both stuck. Otherwise the switches to be tested are diagnosed as stuck, which was not possible in the prior art because the voltage across the capacitor was in any case substantially equal to the charging voltage, which cannot rule out the case where the switches of the charging terminal are stuck.

[0029] This third step is carried out in a case where the vehicle's computer has no information on whether or not the customer can access the vehicle's dangerous voltages when the charging cable is not connected, for example if the vehicle does not have a charging hatch closing sensor, or if this sensor is defective. Therefore, the diagnosis carried out following this third comparison step allows the user to safely disconnect the charging cable only when at least one of the two switches to be tested is not diagnosed as stuck.

[0030] Thanks to the invention, a more in-depth diagnosis of the switches used during charging with the voltage booster is therefore possible and allows the user to disconnect their charging cable without risking electric shock.

[0031] In one way of carrying out the invention, the motor and the inverter are part of the voltage booster stage, and the voltage booster stage comprises a switch, called a booster switch, connected by a first of its terminals to the positive terminal of the capacitor and by a second of its terminals to a neutral point of the motor, the method comprising the steps of, when the load has used the voltage booster stage and when the method has not diagnosed any sticking of the switches to be tested:

[0032] - opening command of the elevator switch,

[0033] - inverter control in capacity discharge,

[0034] - comparison of a voltage across the capacitor or a phase current of the inverter with a low voltage threshold of the capacitor or phase current respectively, and if the voltage across the capacitor is lower than the low voltage threshold of the capacitor or if the phase current of the inverter is higher than the low phase current threshold, detection of a sticking of the boost switch. Otherwise, if the voltage across the capacitor is higher than the low voltage threshold of the capacitor or if the phase current of the inverter is zero for a period immediately following the discharge command, the method determines that the boost switch is not stuck.

[0035] The motor of the charging system is an alternating current motor, for example a three-phase motor. In this way of implementing the invention, the stator inductances of the three-phase motor are used as current storage inductances in the voltage booster stage, these stator inductances discharging into the traction battery through the inverter according to a switching duty cycle of the inverter switches, set in particular as a function of voltage or current measurements made by the charging system. By reusing components used for the vehicle's traction to form the voltage booster stage, space in the engine compartment is saved, and the cost of specific components to produce this stage is saved.

[0036] The boost switch diagnostics ensure proper vehicle operation after charging using the boost switch. When the boost switch is stuck, the parallel capacitance of the motor and inverter can impair vehicle operation while driving.

[0037] The charging system includes in particular:

[0038] - a switch, called a positive direct current switch, connected by a first of its terminals to the positive terminal of the charging socket and by a second of its terminals to a positive input terminal of the voltage booster stage, and

[0039] - a switch, called a negative direct current switch, connected by a first of its terminals to the negative terminal of the load socket and by a second of its terminals to a negative input terminal of the voltage booster stage, the switches to be tested being the positive direct current switch and the negative direct current switch when the load has used the voltage booster stage, the voltage between the second terminals of the switches to be tested then being called the booster voltage, which also corresponds to the voltage across the capacitor.

[0040] In one embodiment of the invention, the charging system comprises a switch, called a bypass switch, connected by a first of its terminals to the first terminal of the positive direct current switch, and by a second of its terminals to the second terminal of the positive battery switch, the switches to be tested being the negative direct current switch and the bypass switch when the load has not used the voltage booster stage, the voltage between the second terminals of the switches to be tested then being called the inverter voltage.In this embodiment of the invention, the charging system comprises means for direct connection of the charging terminal to the traction battery, i.e. without passing through the voltage booster stage, only a few conductors or components of zero or almost zero resistance such as battery switches separating the charging socket from the traction battery when these direct connection means are used.

[0041] These direct connection means are advantageously used when the vehicle is connected to a charging terminal providing a charging voltage higher than the maximum no-load voltage of the traction battery. By not passing through the voltage boost stage, the charging current from such a charging terminal does not then suffer electrical losses in the voltage boost stage. This also avoids oversizing the vehicle's electric motor and inverter to enable them to support a charging current from such a charging terminal.

[0042] This embodiment optimizes the number of switches of the charging system according to the invention comprising this direct connection, by using the negative direct current switch both for charging the traction battery passing through the voltage booster stage and for charging the battery not passing through this stage. This embodiment of the direct connection means makes it possible not to require closing the positive direct current relay during charging of the traction battery not passing through the voltage booster stage. In addition, this embodiment makes it possible to avoid coupling the capacitance at the input of the voltage booster stage, with a smoothing capacitance connected at the input of the traction battery, this coupling being able to damage the load or the charging system during charging of the traction battery not using the voltage booster stage.

[0043] The invention therefore applies to a charging system using the voltage booster stage at least to charge the traction battery when the charging voltage delivered by the charging terminal is lower than the maximum no-load voltage of the battery, the charging system being able to also comprise means for direct connection to the battery, in this case these direct connection means being used when the charging voltage delivered by the charging terminal is higher than the maximum no-load voltage of the battery.

[0044] According to an advantageous characteristic of the method according to the invention, in the case where the charging system comprises means for direct connection to the battery, when a closure of the charging hatch has been detected, the second comparison step is followed, whether or not the load has used the voltage booster stage, the bypass switch, the positive direct current and negative direct current switches being controlled to open and the positive and negative battery switches being controlled to close, by a fourth comparison step, between on the one hand the voltage at the terminals of the charging socket and on the other hand at least one differential voltage threshold among a low differential voltage threshold and an intermediate differential voltage threshold,resulting in detection of a sticking of the bypass switch and the negative direct current switch if the voltage across the charging socket is higher than the intermediate differential voltage threshold, or of a sticking of the positive direct current switch and the negative direct current switch if the voltage across the charging socket is between the low threshold and the intermediate differential voltage threshold.,

[0045] Advantageously, when the fourth comparison step determines that the voltage across the terminals of the charging socket is lower than the low differential voltage threshold, then the fourth comparison step is followed by a fifth comparison step, between on the one hand a common mode voltage of the positive terminal of the charging socket and on the other hand at least one common mode voltage threshold among a low common mode voltage threshold and an intermediate common mode voltage threshold, resulting in a determination of non-sticking of the bypass switch and the positive direct current switch when the common mode voltage of the positive terminal of the charging socket is lower than the low common mode voltage threshold,or a sticking of the positive direct current switch if the common mode voltage of the positive terminal of the load socket is between the low common mode voltage threshold and the intermediate common mode voltage threshold, or a sticking of the bypass switch if the common mode voltage of the positive terminal of the load socket is higher than the intermediate common mode voltage threshold.,

[0046] Advantageously again, when the fourth comparison step determines that the voltage across the terminals of the charging socket is lower than the low differential voltage threshold, then the fourth comparison step is followed by a sixth comparison step between, on the one hand, a common mode voltage of the negative terminal of the charging socket and, on the other hand, a low common mode voltage level, resulting in a determination of non-sticking of the negative direct current switch when the common mode voltage of the negative terminal of the charging socket is lower than the low common mode voltage level, or otherwise of sticking of the negative direct current switch. The fifth and sixth comparison steps are, for example, carried out in parallel after the fourth comparison step.

[0047] The different differential or common mode voltage thresholds make it possible to diagnose a stuck switch of one of the switches among the bypass switch and the positive direct current and negative direct current switches, despite the fact that the user having unplugged the plug, the two switches which were used for the load are not known a priori.

[0048] In another case of use of the method according to the invention, when the load has not used the voltage booster stage, when a difference between the voltages compared during the second comparison step is less than a predefined voltage difference, and in the absence of information on the closure of a charging hatch of the vehicle used to access the charging socket, the method continues with the steps of:

[0049] - opening control of the positive and negative battery switches,

[0050] - additional comparison of the voltage at the terminals of the charging socket with the predefined safety voltage, and if the voltage at the terminals of the charging socket is lower than the predefined safety voltage:

[0051] - closing control of the positive and negative battery switches,

[0052] - additional comparison of the voltage across the charging socket with the predefined safety voltage, and if the voltage across the charging socket is higher than the predefined safety voltage, detection of sticking of the negative DC switch and the bypass switch or otherwise determination of the fact that at least one switch among the bypass switch and the negative DC switch is not stuck.

[0053] Thus in this use case, the method according to the invention cleverly uses the voltage differences measured according to the state of the positive and negative battery switches to carry out the diagnosis of the negative direct current and bypass switches.

[0054] In this other case of use of the method according to the invention, when the voltage at the terminals of the charging socket is higher than the predefined safety voltage during the additional comparison of the voltage at the terminals of the charging socket with the predefined safety voltage, the method continues with the steps of:

[0055] - comparing the inverter voltage with the predefined safety voltage, resulting in determining that at least one of the bypass switch and the negative DC switch is not stuck when the inverter voltage is lower than the predefined safety voltage, or otherwise prohibiting the disconnection of a charging cable to which the charging plug is connected, looping back to the additional comparison step.

[0056] The invention thus limits as much as possible the cases where the user is not authorized to disconnect the charging plug.

[0057] Returning to a more general case of use of the invention, according to another advantageous characteristic of the method according to the invention, when the third comparison step determines that the voltage across the terminals of the charging socket is equal to the voltage of the booster, then the method detects a sticking of the positive direct current switch and the negative direct current switch, otherwise the method determines that at least one switch among the positive direct current switch and the negative direct current switch is not stuck. Of course, given the level of voltages compared, in this application a voltage equality is evaluated to a tolerance of a few volts.

[0058] Furthermore, advantageously in the method according to the invention, when the load has used the voltage booster stage, and when the first comparison step determines that the voltage across the terminals of the load socket is lower than the predefined safety voltage, or when the second comparison step determines that the difference between the voltage of the booster and the voltage across the terminals of the load socket is greater than the predefined voltage difference, then the method determines that at least one switch among the positive direct current switch and the negative direct current switch is not stuck.

[0059] Similarly, when the load has not used the voltage boost stage, and when the first comparison step determines that the voltage across the load socket is lower than the preset safety voltage, or when the second comparison step determines that the difference between the inverter voltage and the voltage across the load socket is greater than the preset voltage difference, then the method determines that at least one of the bypass switch and the negative DC switch is not stuck.

[0060] Advantageously again, when the method according to the invention determines that at least one switch among the positive direct current switch and the negative direct current switch is not stuck, the load having used the voltage booster stage, or that at least one switch among the bypass switch and the negative direct current switch is not stuck, the load not having used the voltage booster stage, the method continues, the negative direct current switches on the one hand, and positive direct current or respectively bypass on the other hand, being commanded to open, with a seventh comparison step, between on the one hand a common mode voltage of the negative terminal of the load socket and on the other hand a first low limit of common mode voltage,resulting in a determination of non-sticking of the negative direct current switch when the common mode voltage of the negative terminal of the load socket is lower than the first low common mode voltage limit, and with an eighth comparison step, between on the one hand a common mode voltage of the positive terminal of the load socket and on the other hand a second low common mode voltage limit, resulting in a determination of non-sticking of the positive direct current switch or respectively of the bypass switch when the common mode voltage of the positive terminal of the load socket is lower than the second low common mode voltage limit.,

[0061] The seventh and eighth comparison steps are, for example, performed in parallel.

[0062] Advantageously, during the seventh comparison step, when the common mode voltage of the negative terminal of the load socket is greater than the first low voltage limit, the method according to the invention continues, after commanding the positive direct current switch or respectively bypass switch to close, with a ninth comparison step, between on the one hand the voltage of the booster or respectively the inverter voltage and on the other hand the voltage at the terminals of the load socket, resulting in a detection of a sticking of the negative direct current switch if the voltage of the booster or respectively the inverter voltage is equal to the voltage at the terminals of the load socket, or otherwise a determination of non-sticking of the negative direct current switch.

[0063] Advantageously, during the eighth comparison step, when the common mode voltage of the positive terminal of the load socket is greater than the second low voltage limit, the method continues, after commanding the negative direct current switch to close, with a tenth comparison step, between on the one hand the voltage of the booster or respectively the inverter voltage and on the other hand the voltage at the terminals of the load socket, resulting in a detection of a sticking of the positive direct current switch or respectively the bypass switch if the voltage of the booster or respectively the inverter voltage is equal to the voltage at the terminals of the load socket, or otherwise in a determination of a non-sticking of the positive direct current switch or respectively the bypass switch.

[0064] Other characteristics and advantages of the invention will become apparent from the following description on the one hand, and from several examples of embodiment given for informational and non-limiting purposes with reference to the attached schematic drawings on the other hand, in which:

[0065] [fig i] schematically represents an electric or hybrid vehicle connected to a charging terminal and comprising a charging system, the vehicle implementing a method according to the invention for the end of charging and for diagnosing power switches of the vehicle charging system, in one embodiment of the invention,

[0066] [fig 2] represents the first steps of the end of charge and diagnostic method according to the invention, implemented by the vehicle of figure i, in the case where the charge which has just ended has used a voltage booster stage of the vehicle's charging system,

[0067] [fig 3] represents steps following first steps of the end of charge and diagnostic process of figure 2, when these first steps have not diagnosed any sticking of switches between the charging terminal and the voltage booster stage,

[0068] [fig 4] represents steps following first steps of the end of charge and diagnostic method of figure 2, when there remains a voltage at the terminals of the charging socket and a closure of a charging hatch closing access to the charging socket is signaled to a computer of the vehicle implementing the method according to the invention,

[0069] [fig 5] represents the first steps of the end of charge and diagnostic method according to the invention, implemented by the vehicle of figure 1, in the case where the charge which has just ended has not used the voltage booster stage of the vehicle's charging system,

[0070] [fig 6] represents steps following the first steps of the end of charge and diagnostic method of figure 5, when there is still a voltage at the terminals of the charging socket and the vehicle computer implementing the method according to the invention has no information on a potential closure of the charging hatch, and

[0071] [fig 7] represents steps following steps of the end of charge and diagnostic method of figure 2, 5 or 6, when the method according to the invention determines that at least one switch among switches used during charging and upstream of the voltage booster or allowing the charging socket to be directly connected to the traction battery, is not stuck.

[0072] According to one embodiment of the invention, an electric or hybrid vehicle 30 illustrated in FIG. 1 comprises a charging system 32. The vehicle 30 comprises a traction battery 2, and the charging system 32 has just made it possible to recharge the traction battery 2 using the energy supplied by a direct current charging terminal 60, to which the vehicle 30 is connected by a charging cable 70. At the end of this direct current charging, the vehicle implements a method 1 for ending charging and diagnosing power switches of the charging system 32 according to the invention, shown in FIGS. 2 to 7.

[0073] The charging system 32 is now described in relation to FIG. 1 and with other elements of the vehicle 30, to better understand how these power switches are used when charging the traction battery 2.

[0074] The vehicle comprises a traction inverter 3 and a three-phase electric motor 4 connected to the wheels of the vehicle by a transmission chain, the inverter 3 and the motor 4 being powered by the traction battery 2 to set the vehicle in motion.

[0075] The vehicle comprises for this purpose, to connect the traction battery 2 to the inverter 3, a first switch 11, called the positive battery switch, connected by a first of its terminals to a positive terminal of the traction battery 2 and by a second of its terminals to a positive input terminal of the inverter 3, and a second switch 12, called the negative battery switch, connected by a first of its terminals to a negative terminal of the traction battery 2 and by a second of its terminals to a negative input terminal of the inverter 3. By input of the inverter is meant here the part of the inverter receiving a direct current and transmitting a rectified current, that is to say that the input is understood in relation to the inverter function. Similarly in this application the terms "input" or "output" are understood in relation to the function of the component or electrical assembly to which reference is made. A smoothing capacitor 7 is connected to the input of the inverter.It smooths the current entering battery 2 when inverter 3 is used as a current rectifier at the output of electric motor 4 operating in generator mode.

[0076] The positive 11 and negative 12 battery switches therefore constitute means of connecting the traction battery 2 with the input of the inverter 3. The inverter 3 is also directly connected at the output to the electric motor 4, i.e. without an intermediate switch.

[0077] The vehicle also includes a charging socket 8 connected to the direct current charging terminal 60 via the charging cable 70. This charging socket 8 is for example a CHAdeMO connector complying with the IEC 61851-23, -24 standard. Alternatively, the vehicle only includes a single charging socket allowing connection to both a direct current charging terminal and an alternating current charging terminal, for example a Combo DC charging socket complying with the IEC 62196-3 standard. In this case, the vehicle 30 also includes alternating current charging means. In yet another alternative, the vehicle only includes a charging socket intended exclusively to be connected to a direct current charging terminal.

[0078] The charging system 32 comprises a voltage booster stage 5, comprising the inverter 3, the motor 4, and a capacitor 6 connected to the input of this voltage booster stage 5. More precisely, a positive terminal of the capacitor 6 is connected to the neutral point of the motor 4 via a switch 16, called a booster switch, and a negative terminal of the capacitor 6 is connected to the negative input terminal of the inverter 3. This voltage booster stage 5 is used by the vehicle when charging the traction battery 2 using a charging voltage supplied by a charging terminal lower than the maximum no-load voltage of the traction battery 2.

[0079] To do this, the charging system 32 comprises control means 40 for the inverter 3 and the motor 4 capable of transforming this charging voltage at the input of the voltage booster stage 5 into a voltage at the output of the voltage booster stage 5, higher than that of the traction battery 2. The stator inductances of the electric motor 4 are then used as current storage inductances in the voltage booster stage 5, these stator inductances discharging into the traction battery 2 through the inverter 3 according to a switching duty cycle of the switches of the inverter 3, fixed by the control means 40, which also measure a voltage VB at the terminals of the capacitor 6. The charging system 32 comprises, in addition to means for measuring this voltage VB, means for measuring at least one phase current IB passing through the inverter 3-

[0080] The switch 16, called a step-up switch, is connected by a first of its terminals to the positive terminal of the capacity of the step-up 6 and by a second of its terminals to the neutral point of the electric motor 4. This step-up switch 16 makes it possible to disconnect the capacity of the step-up 6 at the input of the voltage step-up stage 5 outside the charging phases of the traction battery 2 by an external charging terminal, in particular this step-up switch 16 is open when the vehicle is running. Thus, when the vehicle is running, capacitive coupling of the capacity of the step-up 6 with the electric motor 4 is avoided.

[0081] The control means 40 of the inverter 3 are for example a microcontroller controlling the switches of the inverter 3, both in traction mode and in charging mode of the vehicle using the voltage booster stage 5.

[0082] The charging system 32 further comprises means for connecting the charging socket 8 to the input of the voltage booster stage 5, these means comprising:

[0083] - a switch 13, called a positive direct current switch, connected by a first of its terminals to a positive terminal of the charging socket 8 and by a second of its terminals to the step-up switch 16, and

[0084] - a switch 14, called a negative direct current switch, connected by a first of its terminals to a negative terminal of the load socket 8 and by a second of its terminals to the negative input terminal of the inverter 3-

[0085] These switches 13, 14 are used to recharge the traction battery 2 via the voltage booster stage 5 when a charging voltage of a charging terminal to which the charging socket 8 is connected is lower than the maximum no-load voltage of the battery 2.

[0086] Finally, the charging system 32 also comprises means for connecting the charging socket 8 directly to the traction battery 2, used to recharge the latter when a charging voltage of a charging terminal to which the charging socket 8 is connected is greater than the maximum no-load voltage of the battery 2. These connection means comprise the negative direct current switch 14 and a switch 15, called a bypass switch, connected by a first of its terminals to the first terminal of the positive direct current switch 13, and by a second of its terminals to the second terminal of the positive battery switch 11.

[0087] The switches 11, 12, 13, 14 and 15 are grouped in a connection box 9 of the charging system 32. The connection box 9 also comprises a pre-charging relay 10 connected by one of its terminals to the positive terminal of the traction battery 2 and by the other of its terminals to the positive terminal of the inverter 3. A pre-charging resistor is connected between the pre-charging relay 10 and the positive terminal of the battery 2. Before any charging of the battery 2, the pre-charging relay 10 is first closed to charge the smoothing capacitor 7, then the pre-charging relay 10 is opened and the positive battery switch 11 is closed. The pre-charging relay 10 and the pre-charging resistor form a pre-charging device. It should be noted that other types of pre-charging devices can be used instead of such a relay and resistor system.The charging system 32 also comprises one or more software and / or hardware modules of a main computer 50 of the vehicle. In particular, the main computer 50 comprises means of communication with the charging terminal 60 and means of controlling the power switches 10, 11, 12, 13, 14, 15 and 16, these means of communication and control being part of the charging system 32. Means of controlling the power switches 10, 11, 12 are also present in a management system 20 of the traction battery 2 with which the main computer 50 communicates, the management system 20 possibly being an integral part of the charging system 32.

[0088] The management system 20 of the traction battery 2 is coupled to a sensor 22 of a current entering the battery and of a voltage VDC at the terminals of the charging socket 8, which allows it to supervise a charge of the battery 2. The voltage VDC at the terminals of the charging socket 8 is a differential voltage between the two terminals of this charging socket 8. The management system 20 of the battery 2 also comprises means for controlling the bypass switch 15 and the positive 13 and negative 14 direct current switches. Thus, when the management system 20 of the battery 2 detects a fault during charging, it can interrupt it for safety reasons without intervention of the main computer 50 of the vehicle. The switches 10, 11, 12, 13, 14, 15 are therefore each controllable by the management system 20 and by the main computer 50 of the vehicle, thus achieving safety redundancy.Likewise, the elevator switch 16 can be controlled by the main computer 50 and by the control means 40.

[0089] In addition to the sensor 22, the charging system 32 comprises means for measuring a common mode voltage V+ between the positive terminal of the charging socket 8 and a ground of the vehicle 30, and means for measuring a common mode voltage V- between the negative terminal of the charging socket 8 and the ground of the vehicle 30.

[0090] The main computer 50 of the vehicle implements the method 1 for the end of charging and diagnosis of at least some of the power switches 13, 14, 15, 16, using the means or components of the charging system 32. We will now describe in relation to FIG. 2, the implementation of the method i according to the invention when the traction battery 2 has just been recharged via the charging terminal 60, using the voltage booster stage 5. In this case of use of the invention, the charging terminal 60 cannot for example supply a voltage greater than 400V while the traction battery 2 has a maximum no-load voltage of 800V. The charging current which has just ended has therefore passed through the positive 13 and negative 14 direct current switches, the boost switch 16, the positive 11 and negative 12 battery switches, but has not used the bypass switch 15 which remained open during charging.

[0091] The method 1 starts during a first step 100, during which it completes an exchange of messages with the charging terminal 60, which allows it to ensure that its request to open switches 62, 64 of the charging terminal 60 has been received and accepted, during the implementation of an end-of-charge protocol allowing the implementation of a diagnosis of power switches of the vehicle 30. The voltage delivered by the charging terminal 60 is therefore theoretically zero (unless there is a fault in the charging terminal 60) during the first step 100.

[0092] It should be noted that the positive battery switches 11 and negative 12, as well as the booster switch 16 are closed during this first step 100.

[0093] The next step 110 is the opening command of the positive 13 and negative 14 direct current switches.

[0094] After a few milliseconds, the method 1 implements the next step 120, which is a first step of comparison between on the one hand the voltage VDC at the terminals of the charging socket 8 and on the other hand a predefined safety voltage Si, taken here equal to 60V. Of course, as a variant, another predefined safety voltage value is chosen, in particular according to the standards in force relating to electrical safety.

[0095] When in this first comparison step 120, the method 1 determines that the voltage VDC across the terminals of the charging socket 8 is lower (branch Y) than the predefined safety voltage Si, then the method 1 determines that at least one switch among the positive direct current switch 13 and the negative direct current switch 14 is not stuck, and the method 1 continues (reference A) with step 470 referenced in FIG. 7, commented on later. It should be noted that in this application, the comparison steps use inequality conditions chosen from strict or broad conditions, without changing the nature of the invention. The strict or broad nature of the inequalities is therefore not specified in this embodiment of the invention.

[0096] When, on the contrary, in this first comparison step 120, the method 1 determines that the voltage VDC at the terminals of the charging socket 8 is higher (branch N) than the predefined safety voltage Si, then the first comparison step 120 is followed by a second comparison step 130, between on the one hand the voltage VDC at the terminals of the charging socket 8, and on the other hand the voltage VB measured by the charging system 32 at the terminals of the capacitor 6, called the booster voltage.

[0097] When in this second comparison step 130, the method 1 determines that the difference in absolute value between the voltage VDC at the terminals of the charging socket 8 and the voltage of the booster VB is greater (branch Y) than a predefined voltage difference S2, equal to 30 V in this embodiment of the invention, then the method 1 determines that at least one switch among the positive direct current switch 13 and the negative direct current switch 14 is not stuck, and the method 1 continues with step 470 referenced in FIG. 7, commented on later. Of course, another value can be chosen for the predefined voltage difference S2, in particular depending on the use cases of the charging system 32.

[0098] When in this second comparison step 130, the method 1 determines that the difference in absolute value between the voltage VDC at the terminals of the charging socket 8 and the voltage of the booster VB is lower (branch N) than the predefined voltage difference S2, then in the case where a sensor for closing a charging hatch giving access to the charging socket 8 is functional (branch Y of the condition 135), the following step is a step 170 of commanding the opening of the positive 11 and negative 12 battery switches, then an authorization to disconnect the charging cable 70 if one of the following conditions is met:

[0099] - the voltage VDC across the terminals of the charging socket 8, the common mode voltage V+ between the positive terminal of the charging socket 8 and the ground of the vehicle 30 and the common mode voltage V- between the negative terminal of the charging socket 8 and the ground of the vehicle 30 are lower than the predefined safety voltage If, ​​or

[0100] - a voltage Vo at the terminals of inverter 3 is lower than the predefined safety voltage If, ​​and if one of these conditions is met, the computer waits for the reception of information on the closure of the hatch then continues (reference B) with step 240 referenced in figure 4 and commented on later.

[0101] When in this second comparison step 130, the method 1 determines that the difference in absolute value between the voltage VDC at the terminals of the charging socket 8 and the voltage of the booster VB is less than the predefined voltage difference S2, and when the computer 50 of the vehicle has no information on a possible disconnection of the charging cable 70 (branch N of the condition 135), for example because the vehicle 30 is not equipped with a charging hatch closing sensor or this sensor is faulty, then the following step is a step 140 of discharging the capacitor 6 at the input of the voltage booster stage 5, so that the voltage of the booster VB reaches a predefined voltage, for example 100V. For this, the computer 5 uses the control means 40 of the inverter 3.

[0102] The discharge step 140 is followed, after a few milliseconds of waiting, by a third comparison step 150, between on the one hand the voltage VDC at the terminals of the charging socket 8 and on the other hand the voltage VB of the booster.

[0103] When in the third comparison step 150, the method 1 determines that the voltage VDC across the terminals of the charging socket 8 is equal to the voltage of the booster VB (branch Y), then the method 1 detects 160 a sticking of the positive direct current switch 13 and a sticking of the negative direct current switch 14, otherwise (branch N) the method 1 determines that at least one switch among the positive direct current switch 13 and the negative direct current switch 14 is not stuck. In this latter case, the method i continues with step 470 referenced in FIG. 7, commented on later.

[0104] It should be noted that in the case where the negative 14 and positive 13 direct current switches are both diagnosed as stuck, disconnection is authorized after opening the positive 11 and negative 12 battery switches and checking that these latter switches are not stuck.

[0105] It is now assumed that at the end of the method 1 according to the invention, the computer 50 has determined a non-sticking, that is to say an absence of blocking in the closed position, of the positive 13 and negative 14 direct current switches. This determination could have taken place for example because at the end of the first comparison step 120, the voltage at the terminals of the charging socket 8 was lower than the predefined safety voltage Si, and because the method then determined (steps 490 and 545 commented on later in relation to FIG. 7) that the common mode voltage of each of the terminals of the charging socket 8 was also lower than the predefined safety voltage Si.

[0106] Method 1 then implements steps of Figure 2, aimed at determining a diagnosis of the step-up switch 16.

[0107] The first step of this new diagnosis is the command 180 to open the booster switch 16. This first command step 180 to open is followed by a command step 190 of the inverter 3 to discharge the capacitor 6, then immediately after by a comparison step 215 of the voltage of the booster VB with a low threshold S3 of the voltage of the capacitor 6, for example 60V, or of a phase current IB in the inverter 3 with a low threshold S4 of the phase current IB of a few amperes, for example 5 amperes.

[0108] If the method 1 determines 220 in this comparison step 215, that the voltage of the booster VB is lower than the low voltage threshold S3 of the capacitor 6 after a few seconds, or that the phase current IB in the inverter 3 is higher than the low current threshold S4 of the phase current IB for more than a few milliseconds, it is because the discharge of the capacitor 6 could have taken place, and the method i therefore determines in a step 230 that the booster switch 16 is stuck.

[0109] If, on the contrary, the method 1 determines 200 in this comparison step 215, that the voltage of the booster VB is still higher than the low voltage threshold S3 of the capacitor 6 after a few seconds, or that the phase current IB in the inverter 3 is close to zero for a few milliseconds, it is because the discharge of the capacitor 6 could not be carried out, and the method 1 therefore determines in a step 210 that the booster switch 16 is not stuck.

[0110] Figure 3 illustrates the steps following the command 170 to open the positive 11 and negative 12 battery switches, and the receipt by the computer 50 of information about closing the charging hatch. This closing took place while the voltage VDC previously measured at the terminals of the charging socket 8 during the first comparison step 120 was higher than the predefined safety voltage Si, and while the difference between the voltage of the booster VB and the voltage VDC at the terminals of the charging socket was lower than the predefined voltage difference S2. The complete diagnosis of the positive 13 and negative 14 direct current switches could therefore not be carried out. It should be noted that the information about closing the charging hatch is potentially deduced by the computer 50 from the vehicle 30 traveling beyond a certain speed threshold, for example at more than 5 kilometers per hour.

[0111] In this configuration, the first step of this diagnosis with the hatch closed is the command 240 to open the positive direct current 13, negative direct current 14 and bypass 15 switches, when these switches are not already commanded open, and to close the positive 11 and negative 12 battery switches, when these switches are not already commanded closed. This latter case can occur for example between the second comparison step 130 and the discharge step 140 if the computer 50 detects that the vehicle is moving between these two steps.

[0112] It should be noted that in this configuration also, the computer 50 does not know whether the charge that has just ended is a charge that has used the voltage booster stage 5 or a charge that has not used the voltage booster stage 5, in other words the computer 50 does not know whether it must diagnose the positive 13 and negative 14 direct current switches, or respectively the bypass switch 15 and the negative current switch 14. Indeed, the type of charge that has just been carried out is not stored in the computer 50, in this embodiment of the invention.

[0113] The control step 240 is followed by a fourth comparison step 250, between on the one hand the voltage VDC at the terminals of the charging socket 8 and on the other hand a low threshold S5 of differential voltage, set for example at 60V.

[0114] During this fourth comparison step 250, if the method 1 determines that the voltage VDC across the terminals of the charging socket 8 is higher (branch N) than the low differential voltage threshold S5, this means that two switches connected to the charging socket are stuck. The next step in this case is the comparison between the voltage VDC across the terminals of the charging socket 8 and an intermediate differential voltage threshold S6, set here at 500V. If the method 1 determines 260 that the voltage VDC across the terminals of the charging socket 8 is lower than this intermediate differential voltage threshold S6, and higher than the low differential voltage threshold S5, this means that the charging that has just ended has used the voltage booster stage 5, and the method 1 determines 270 that the positive 13 and negative 14 direct current switches are stuck.If, on the contrary, the method determines 280 that the voltage VDC at the terminals of the charging socket 8 is between the intermediate threshold S6 of differential voltage and a high threshold S7 of differential voltage, corresponding for example to 900V, it is because the charging which has just ended has not used the voltage booster stage 5, and the method 1 determines 290 that the bypass switch 15 and the negative direct current switch 14 are stuck.

[0115] During this fourth comparison step 250, if the method 1 determines that the voltage VDC across the terminals of the charging socket 8 is lower (Y branch) than the low differential voltage threshold S5, this means that at least one of the two switches connected to the charging socket is stuck. In this case, the fourth comparison step 250 is followed by a fifth comparison step 300, between on the one hand the common mode voltage V+ of the positive terminal of the charging socket 8 and on the other hand a low common mode voltage threshold S8, set for example at 60V. If the common mode voltage V+ of the positive terminal of the charging socket 8 is lower (Y branch) than the low common mode voltage threshold S8, then the method 1 determines 310 that neither the bypass switch 15 nor the positive direct current switch are stuck.If, on the contrary, method 1 determines that the common mode voltage V+ of the positive terminal of the charging socket 8 is higher (branch N) than the low common mode voltage threshold S8, the next step is the comparison between the common mode voltage V+ of the positive terminal of the charging socket 8 and an intermediate common mode voltage threshold S9, set for example at 500V. If method 1 determines 320 that the voltage VDC at the terminals of the charging socket 8 is lower than this intermediate common mode voltage threshold S9, and higher than the low common mode voltage threshold S8, this means that the charging that has just ended has used the voltage booster stage 5, and method 1 determines 330 that the positive 13 and negative 14 direct current switches are stuck.If, on the contrary, the method determines 340 that the voltage VDC at the terminals of the charging socket 8 is between the intermediate threshold S9 of common mode voltage and a high threshold S10 of common mode voltage, corresponding for example to 900V, it is because the charging which has just ended has not used the voltage booster stage 5, and the method 1 determines 350 that the bypass switch 15 and the negative direct current switch 14 are stuck.

[0116] Furthermore, when the method 1 determines, at the end of the fourth comparison step 250, that at least one of the two switches connected to the charging socket is stuck, the voltage VDC across the terminals of the charging socket 8 being lower than the low differential voltage threshold S5, then the fourth comparison step 250 is followed by a sixth comparison step 360 between, on the one hand, the common mode voltage V- of the negative terminal of the charging socket 8 and, on the other hand, a low common mode voltage level Su, set for example at 60V. If the common mode voltage V- of the negative terminal of the charging socket 8 is lower (branch Y) than the low common mode voltage level Su, then the method i determines 370 that the negative direct current switch 14 is not stuck.If, on the contrary, the common mode voltage V- of the negative terminal of the load socket 8 is higher (branch N) than the low common mode voltage level Su, then the method 1 determines 380 that the negative direct current switch 14 is stuck.

[0117] We will now describe in relation to Figure 5, the implementation of the method 1 according to the invention when the traction battery 2 has just been recharged via the charging terminal 60, without using the voltage booster stage 5. In this case of use of the invention, the charging terminal 60 can provide a voltage greater than or equal to the maximum no-load voltage of the traction battery 2, of 800V. The current of the charge which has just ended has therefore notably passed through the negative current switches 14 and bypass 15, and the positive battery switches 11 and negative 12, but has not used the booster switch 16 which remained open during the charge.In this use case, the first steps of method 1 are essentially identical to those in the case where the load used the voltage booster stage 5 and are therefore referenced in the same way, although the differences relating to the switches involved and to certain comparison voltages are indicated.

[0118] Process 1 starts during the first step 100, identical to that of the case of a charge using the voltage booster 5. In particular, the positive 11 and negative 12 battery switches are closed during this first step 100.

[0119] The next step 110 is the opening command of the negative direct current switches 14 and bypass 15.

[0120] After a few milliseconds, the method implements the next step 120, which is the first step of comparison between on the one hand the voltage VDC at the terminals of the charging socket 8 and on the other hand the predefined safety voltage Si.

[0121] When in this first comparison step 120, the method 1 determines that the voltage VDC at the terminals of the charging socket 8 is lower (branch Y) than the predefined safety voltage Si, then the method 1 determines that at least one switch among the bypass switch 15 and the negative direct current switch 14 is not stuck, and the method 1 continues with step 470 referenced in figure 7, commented on later.

[0122] When, on the contrary, in this first comparison step 120, the method 1 determines that the voltage VDC at the terminals of the charging socket 8 is higher (branch N) than the predefined safety voltage Si, then the first comparison step 120 is followed by a second comparison step 130, between on the one hand the voltage VDC at the terminals of the charging socket 8, and on the other hand the voltage Vo measured by the charging system 32 at the terminals of the inverter 3, called inverter voltage.

[0123] When in this second comparison step 130, the method 1 determines that the difference in absolute value between the voltage VDC at the terminals of the load socket 8 and the inverter voltage Vo is greater (branch Y) than the predefined voltage difference S2, then the method 1 determines that at least one switch among the bypass switch 15 and the negative direct current switch 14 is not stuck, and the method 1 continues with step 470 referenced in FIG. 7, commented on later.

[0124] When in this second comparison step 130, the method 1 determines that the difference in absolute value between the voltage VDC at the terminals of the charging socket 8 and the inverter voltage Vo is lower (branch N) than the predefined voltage difference S2, then in the case where a charging hatch closing sensor is functional (branch Y of condition 135), the following step is a step 170 of commanding the opening of the positive 11 and negative 12 battery switches, then an authorization to disconnect the charging cable if one of the following conditions is met:

[0125] - the voltage VDC across the terminals of the charging socket 8, the common mode voltage V+ between the positive terminal of the charging socket 8 and the ground of the vehicle 30 and the common mode voltage V- between the negative terminal of the charging socket 8 and the ground of the vehicle 30 are lower than the predefined safety voltage If, ​​or

[0126] - the inverter voltage Vo is lower than the predefined safety voltage If, ​​and if one of these conditions is met, the computer 50 waits for the reception of information on the closing of the hatch then continues with step 240 referenced in figure 4, this step 240 and the following ones being identical to the case where the load has used the voltage booster stage 5.

[0127] When in the second comparison step 130, the method 1 determines that the difference in absolute value between the voltage VDC at the terminals of the charging socket 8 and the inverter voltage Vo is less than the predefined voltage difference S2, and when the computer 50 of the vehicle has no information on a possible disconnection of the charging cable (branch N of the condition 135), for example because the vehicle is not equipped with a charging hatch closing sensor or this sensor is faulty, then the method 1 continues (reference C) with steps illustrated in figure 6. These steps are:

[0128] - an opening command 390 of the positive 13 and negative 14 battery switches, then after a few seconds,

[0129] - an additional 400 comparison of the VDC voltage at the terminals of the charging socket 8 with the predefined safety voltage Si, and if the VDC voltage at the terminals of the charging socket 8 is lower (Y branch) than the predefined safety voltage Si:

[0130] - a closing command 410 of the positive 13 and negative 14 battery switches, then

[0131] - an additional comparison 420 of the VDC voltage at the terminals of the charging socket 8 with the predefined safety voltage Si, and if the method 1 determines that the VDC voltage at the terminals of the charging socket 8 is higher (branch N) than the predefined safety voltage Si, then the method 1 detects 430 the sticking of the negative direct current switch 14 and the sticking of the bypass switch 15. In this case, disconnection is authorized after opening the positive 11 and negative 12 battery switches and checking that these latter switches are not stuck.

[0132] On the contrary, if during this additional comparison step 420, the method 1 determines that the voltage VDC at the terminals of the charging socket 8 is lower (branch Y) than the predefined safety voltage Si, then the method 1 determines that at least one switch among the bypass switch 15 and the negative direct current switch 14 is not stuck, and the method 1 continues with step 470 referenced in figure 7, commented on later.

[0133] When, during the additional comparison 400, the voltage VDC across the terminals of the charging socket 8 is higher (branch N) than the predefined safety voltage Si, then this additional comparison step 400 is followed by a comparison step 440 of the inverter voltage Vo with the predefined safety voltage Si. If the inverter voltage VO is lower (branch Y) than the predefined safety voltage Si, the user is authorized to disconnect the charging cable 70, the method 1 determines 450 that at least one switch among the bypass switch 15 and the negative direct current switch 14 is not stuck, and the method 1 continues with the step 470 referenced in FIG. 7, commented on later. On the contrary, if the inverter voltage Vo is higher (branch N) than the predefined safety voltage Si, the method 1 prohibits 460 the user from disconnecting the charging cable 70 and loops back to the additional comparison step 400.Indeed, in this case, a dangerous voltage persists at the terminals of the charging socket 8, and at the terminals of the inverter, which may be the result of simultaneous sticking of the switches 62, 64 of the charging terminal 60 and the negative direct current switches 14 and bypass 15, or of the switches 62, 64 of the charging terminal 60 and the positive battery switches 11 and negative 12, or of the negative direct current switches 14 and bypass 15 and the positive battery switches 11 and negative 12. The user must then press an emergency button on the charging terminal 60 to lower the voltage delivered by the charging terminal and allow the charging socket 8 to be disconnected.

[0134] Finally, when the method 1 has determined, in one of the cases mentioned above in relation to figures 2, 5 or 6, that at least one switch among the bypass switch 15 and the negative direct current switch 14 is not stuck, the load not having used the voltage booster stage 5, or that at least one switch among the negative direct current switches 14 and positive direct current switches 13 is not stuck, the load not having used the voltage booster stage 5, then: - the user is authorized to disconnect the charging cable and

[0135] - method i continues with steps of figure 7, that is to say with step 470 of opening control of the switches not already controlled open among the bypass switches 15, positive direct current 13 and negative direct current 14.

[0136] During this opening command step 470, the positive 11 and negative 12 battery switches are closed.

[0137] The opening command step 470 is then followed by two comparison steps taking place in parallel and / or one after the other, these steps being:

[0138] - a seventh comparison step 480 between on the one hand the common mode voltage V- of the negative terminal of the charging socket 8 and on the other hand a first low limit S12 of common mode voltage, for example 60V, and

[0139] - an eighth comparison step 540, between on the one hand the common mode voltage V+ of the positive terminal of the charging socket 8 and on the other hand a second low limit S13 of common mode voltage, for example 60V.

[0140] When in the seventh comparison step 480, the method 1 determines that the common mode voltage V- of the negative terminal of the load tap 8 is lower (Y branch) than the first common mode voltage low limit S12, then the method 1 determines 490 that the negative DC switch is not stuck. Similarly, when in the eighth comparison step 540, the method 1 determines that the common mode voltage V+ of the positive terminal of the load tap 8 is lower (Y branch) than the second common mode voltage low limit S13, then the method 1 determines 545 that the positive DC switch 13 is not stuck, when the load has used the voltage boost stage 5, or that the bypass switch 15 is not stuck, when the load has not used the voltage boost stage 5.

[0141] When, on the contrary, in the seventh comparison step 480, the method 1 determines that the common mode voltage V- of the negative terminal of the load socket 8 is higher (branch N) than the first lower limit S12 of common mode voltage, then the seventh comparison step 480 is followed by a step 500 of closing control of the positive direct current switch, if the load has used the voltage booster stage 5, or of the bypass switch 15, if the load has not used the voltage booster stage 5.

[0142] After a few milliseconds, this closing control step 500 is followed by a ninth comparison step 510, in which when the load has used the voltage booster stage, the method 1 compares on the one hand the voltage of the booster VB and on the other hand the voltage VDC at the terminals of the load socket 8, and if the voltage of the booster VB is equal (branch Y) to the voltage VDC at the terminals of the load socket 8, then the method 1 determines 520 that the negative direct current switch 14 is stuck, otherwise (branch N) the method 1 determines 530 that the negative direct current switch 14 is not stuck.When the load has not used the voltage booster stage, in the ninth comparison step 510, the method 1 compares on the one hand the inverter voltage Vo and on the other hand the voltage VDC across the terminals of the load socket 8, and if the inverter voltage Vo is equal (branch Y) to the voltage VDC across the terminals of the load socket 8, then the method 1 determines 520 that the negative direct current switch 14 is stuck, otherwise (branch N) the method 1 determines 530 that the negative direct current switch 14 is not stuck.

[0143] Similarly, when in the eighth comparison step 540, the method 1 determines that the common mode voltage V+ of the positive terminal of the load socket 8 is greater (branch N) than the second lower limit S13 of common mode voltage, then the eighth comparison step 540 is followed by a step 550 of controlling the closing of the negative direct current switch.

[0144] After a few milliseconds, this closing control step 550 is followed by a tenth comparison step 560, in which when the load has used the voltage booster stage, the method 1 compares on the one hand the voltage of the booster VB and on the other hand the voltage VDC at the terminals of the load socket 8, and if the voltage of the booster VB is equal (branch Y) to the voltage VDC at the terminals of the load socket 8, then the method i determines 570 that the positive direct current switch 13 is stuck, otherwise (branch N) the method 1 determines 580 that the positive direct current switch 13 is not stuck.When the load has not used the voltage booster stage 5, in the tenth comparison step 560, the method 1 compares on the one hand the inverter voltage Vo and on the other hand the voltage VDC at the terminals of the load socket 8, and if the inverter voltage Vo is equal (branch Y) to the voltage VDC at the terminals of the load socket 8, then the method 1 determines 570 that the bypass switch 15 is stuck, otherwise (branch N) the method 1 determines 580 that the bypass switch 15 is not stuck.

[0145] 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.

Claims

CLAIMS i- Method (i) for terminating charging and diagnosing power switches (13, 14, 15, 16) of a charging system (32) of an electric or hybrid vehicle (30), the vehicle (30) comprising a traction battery (2) and an inverter (3) capable of powering an electric motor (4) of the vehicle (30), the charging system (32) comprising at least: - a switch (11), called a positive battery switch, connected by a first of its terminals to a positive terminal of the traction battery (2) and by a second of its terminals to a positive input terminal of the inverter (3), and - a switch (12), called a negative battery switch, connected by a first of its terminals to a negative terminal of the traction battery (2) and by a second of its terminals to a negative input terminal of the inverter (3), - a voltage booster stage (5) comprising at least one capacitor (6) of which a positive terminal is connected to a positive input terminal of the voltage booster stage (5) and a negative terminal is connected to a negative input terminal of the voltage booster stage (5), - two switches (13, 14, 15) used during charging, called switches to be tested, a first switch (13, 15) to be tested being connected by a first of its terminals to a positive terminal of the charging socket (8) and by a second of its terminals to the positive input terminal of the voltage booster stage (5) when the charging has used the voltage booster stage (5), a second switch to be tested (14) being connected by a first of its terminals to a negative terminal of the charging socket (8) and by a second of its terminals to the second terminal of the negative battery switch (12), the method (1) comprising: - a step (110) of controlling the opening of the switches to be tested (13, 14, 15), - a first comparison step (120), between on the one hand a voltage (VDC) at the terminals of the charging socket (8) and on the other hand a predefined safety voltage (Si), the method (i) further comprising, when the voltage (VDC) at the terminals of the charging socket (8) is higher than the predefined safety voltage (Si): - a second comparison step (130), between on the one hand the voltage (VDC) at the terminals of the charging socket (8), and on the other hand a voltage between the second terminals of the switches to be tested (13, 14, 15), the method (1) being characterized in that, when the load has used the voltage booster stage (5), when a difference between the voltages compared during the second comparison step (130) is less than a predefined voltage difference (S2), and in the absence of information on the closing of a charging hatch of the vehicle (30) used to access the charging socket (8), the method (1) further comprises a step of discharging (140) the capacitor (6) then a third comparison step (150), between on the one hand the voltage (VDC) at the terminals of the charging socket (8) and on the other hand the voltage (VB) between the second terminals of the switches to be tested (13, 14). 2- Method (1) for ending charging and diagnosis according to claim 1, in which the motor (4) and the inverter (3) are part of the voltage booster stage (5), the voltage booster stage (5) comprising a switch (16), called a booster switch, connected by a first of its terminals to the positive terminal of the capacitor (6) and by a second of its terminals to a neutral point of the motor (4), the method (1) being characterized in that it comprises the steps of, when the load has used the voltage booster stage (5) and when the method (1) has not diagnosed any sticking of the switches to be tested (13, 14): - control (180) for opening the elevator switch (16), - control (190) of the inverter (3) in discharge of the capacity (6), - comparison (215) of a voltage (VB) across the capacitor (6) or a phase current of the inverter (3) with a low threshold (S3, S4) of the voltage of the capacitor (6) or respectively of the phase current (IB), and if the voltage (VB) across the capacitor (6) is lower than the low threshold (S3) of the voltage of the capacitor (6) or if the phase current (IB) of the inverter (3) is higher than the low threshold (S4) of the phase current (IB), detection (230) of a sticking of the step-up switch (16). 3- Method (i) of end of charge and diagnosis according to claim i or 2, in which the charging system (32) comprises: - a switch (13), called a positive direct current switch, connected by a first of its terminals to the positive terminal of the charging socket (8) and by a second of its terminals to a positive input terminal of the voltage booster stage (5), and - a switch (14), called a negative direct current switch, connected by a first of its terminals to the negative terminal of the load socket (8) and by a second of its terminals to a negative input terminal of the voltage booster stage (5), the switches to be tested being the positive direct current switch (13) and the negative direct current switch (14) when the load has used the voltage booster stage (5), the voltage (VB) between the second terminals of the switches to be tested (13, 14) then being called the booster voltage. 4- Method (1) for ending charging and diagnostics according to claim 3, in which the charging system (32) comprises a switch (15), called a bypass switch, connected by a first of its terminals to the first terminal of the positive direct current switch (13), and by a second of its terminals to the second terminal of the positive battery switch (11), the switches to be tested being the negative direct current switch (14) and the bypass switch (15) when the load has not used the voltage booster stage (5), the voltage (Vo) between the second terminals of the switches to be tested (14, 15) then being called the inverter voltage. 5- Method (1) for the end of charging and diagnosis according to claim 4, in which when a closure of the charging hatch has been detected (135), the second comparison step (130) is followed, whether or not the charge has used the voltage booster stage (5), the bypass switch (15), the positive direct current (13) and negative direct current (14) switches being controlled to open (240) and the positive (11) and negative (12) battery switches being controlled to close (240), by a fourth comparison step (250), between on the one hand the voltage (VDC) at the terminals of the charging socket (8) and on the other hand at least one differential voltage threshold between a low threshold (S5) of differential voltage and an intermediate threshold (S6) of differential voltage, resulting in a detection of a sticking (290) of the bypass switch (15) and of the negative direct current switch (14) if the voltage (VDC) at the terminals of the charging socket (8) is greater than the intermediate threshold (S6) of differential voltage, or of a sticking (270) of the positive direct current switch (13) and of the negative direct current switch (14) if the voltage (VDC) at the terminals of the charging socket (8) is between the low threshold (S5) and the intermediate threshold (S6) of differential voltage. 6- Method (1) for ending charging and diagnosis according to claim 5, wherein when the fourth comparison step (250) determines that the voltage (VDC) across the terminals of the charging socket (8) is lower than the low differential voltage threshold (S5), then the fourth comparison step (250) is followed by a fifth comparison step (300), between on the one hand a common mode voltage (V +) of the positive terminal of the charging socket (8) and on the other hand at least one common mode voltage threshold among a low common mode voltage threshold (S8) and an intermediate common mode voltage threshold (S9), resulting in a determination of a non-sticking (310) of the bypass switch (15) and the positive direct current switch (13) when the common mode voltage (V +) of the positive terminal of the charging socket (8) is lower than the low common mode voltage threshold (S8),or a bonding (330) of the positive direct current switch (13) if the common mode voltage (V+) of the positive terminal of the charging socket (8) is between the low threshold (S8) of common mode voltage and the intermediate threshold (S9) of common mode voltage, or a bonding (350) of the bypass switch (15) if the common mode voltage (V+) of the positive terminal of the charging socket (8) is higher than the intermediate threshold (S9) of common mode voltage., 7- Method (1) for ending charging and diagnosis according to claim 5 or 6, in which when the fourth comparison step (250) determines that the voltage (VDC) at the terminals of the charging socket (8) is lower than the low threshold (S5) of differential voltage, then the fourth step of comparison (250) is followed by a sixth comparison step (360) between on the one hand a common mode voltage (V-) of the negative terminal of the charging socket (8) and on the other hand a low level (Su) of common mode voltage, resulting in a determination of a non-sticking (370) of the negative direct current switch (14) when the common mode voltage (V-) of the negative terminal of the charging socket (8) is lower than the low level (Su) of common mode voltage, or otherwise of a sticking (380) of the negative direct current switch (14). 8- Method (1) for ending charging and diagnosis according to any one of claims 4 to 7, in which when the charging has not used the voltage booster stage (5), when a difference between the voltages compared during the second comparison step (130) is less than a predefined voltage difference (S2), and in the absence of information on the closing of a charging hatch of the vehicle (30) used to access the charging socket (8), the method (1) continues with the steps of: - opening control (390) of the positive (13) and negative (14) battery switches, - additional comparison (400) of the voltage (VDC) at the terminals of the charging socket (8) with the predefined safety voltage (Si), and if the voltage (VDC) at the terminals of the charging socket (8) is lower than the predefined safety voltage (Si): - closing control (410) of the positive (13) and negative (14) battery switches, - additional comparison (420) of the voltage (VDC) across the terminals of the charging socket (8) with the predefined safety voltage (Si), and if the voltage (VDC) across the terminals of the charging socket (8) is higher than the predefined safety voltage (Si), detection (430) of a sticking of the negative direct current switch (14) and the bypass switch (15) or otherwise determination of the fact that at least one switch among the bypass switch (15) and the negative direct current switch (14) is not stuck. 9- Method (1) for ending charging and diagnosis according to claim 8, wherein when the voltage (VDC) at the terminals of the charging socket (8) is higher than the predefined safety voltage (Si) during the additional comparison (400) of the voltage (VDC) at the terminals of the charging socket (8) with the predefined safety voltage (Si), the method continues with the steps of: - comparison (440) of the inverter voltage (Vo) with the predefined safety voltage (Si), resulting in the determination of the fact that at least one switch among the bypass switch (15) and the negative direct current switch (14) is not stuck when the inverter voltage (Vo) is lower than the predefined safety voltage (Si), or otherwise in a prohibition (460) of disconnecting a charging cable (70) to which the charging socket (8) is connected, looping back to the additional comparison step (400). 10- Method (1) for ending charging and diagnosis according to any one of claims 3 to 9, wherein when the third comparison step (150) determines that the voltage (VDC) across the terminals of the charging socket (8) is equal to the voltage of the booster (VB), then the method (1) detects (160) a sticking of the positive direct current switch (13) and the negative direct current switch (14), otherwise the method (1) determines that at least one switch among the positive direct current switch (13) and the negative direct current switch (14) is not stuck. 11- Method (1) for ending charging and diagnosis according to any one of claims 3 to 10, wherein when the charging has used the voltage booster stage (5), and when the first comparison step (120) determines that the voltage (VDC) across the charging socket (8) is lower than the predefined safety voltage (Si), or when the second comparison step (130) determines that the difference between the booster voltage (VB) and the voltage (VDC) across the charging socket (8) is greater than the predefined voltage difference (S2), then the method (1) determines that at least one switch among the positive direct current switch (13) and the negative direct current switch (14) is not stuck. 12- Method (1) for ending charging and diagnosis according to any one of claims 4 to 11, in which when the load has not used the stage voltage booster (5), and when the first comparison step (120) determines that the voltage (VDC) across the load socket (8) is lower than the predefined safety voltage (Si), or when the second comparison step (130) determines that the difference between the inverter voltage (Vo) and the voltage (VDC) across the load socket (8) is greater than the predefined voltage difference (S2), then the method (1) determines that at least one switch among the bypass switch (15) and the negative direct current switch (14) is not stuck. 13- Method (1) for ending charging and diagnosis according to any one of claims 8 to 12 taken in dependence on claim 4, wherein when the method (1) determines that at least one switch among the positive direct current switch (13) and the negative direct current switch (14) is not stuck, the load having used the voltage booster stage (5), or that at least one switch among the bypass switch (15) and the negative direct current switch (14) is not stuck, the load not having used the voltage booster stage (5), the method (1) continues, the negative direct current switches (14) on the one hand, and positive direct current (13) or respectively bypass (15) on the other hand, being commanded to open (470), with a seventh comparison step (480),between on the one hand a common mode voltage (V-) of the negative terminal of the charging socket (8) and on the other hand a first lower limit (S12) of common mode voltage, resulting in a determination of non-sticking (490) of the negative direct current switch (14) when the common mode voltage (V-) of the negative terminal of the charging socket (8) is lower than the first lower limit (S12) of common mode voltage, and with an eighth comparison step (540), between on the one hand a common mode voltage (V +) of the positive terminal of the charging socket (8) and on the other hand a second lower limit (S13) of common mode voltage, resulting in a determination of non-sticking (545) of the positive direct current switch (13) or respectively of the bypass switch (15) when the common mode voltage (V +) of the positive terminal of the charging socket (8) is lower than the second lower limit (S13) of common mode voltage common., 14- Method (i) for ending charging and diagnosis according to claim 13, wherein when the common mode voltage (V-) of the negative terminal of the charging socket (8) is greater than the first low voltage limit (S12), the method (1) continues, after commanding the positive direct current switch (13) or respectively bypass switch (15) to close (500), with a ninth comparison step (510), between on the one hand the voltage of the booster (VB) OR respectively the inverter voltage (Vo) and on the other hand the voltage (VDC) at the terminals of the charging socket (8), resulting in a detection of a sticking (520) of the negative direct current switch (14) if the voltage of the booster (VB) OR respectively the inverter voltage (Vo) is equal to the voltage (VDC) at the terminals of the charging socket (8), or otherwise a determination of non-sticking (530) of the negative direct current switch (14). 15- Method (1) for the end of charging and for diagnosis according to claim 13 or 14, in which when the common mode voltage (V +) of the positive terminal of the charging socket (8) is greater than the second low voltage limit (S13), the method (1) continues, after commanding the negative direct current switch (14) to close (550), with a tenth comparison step (560), between on the one hand the voltage of the booster (VB) OR respectively the inverter voltage (Vo) and on the other hand the voltage (VDC) at the terminals of the charging socket (8), resulting in a detection of a sticking (570) of the positive direct current switch (13) or respectively of the bypass switch (15) if the voltage of the booster (VB) OR respectively of the inverter voltage (Vo) is equal to the voltage (VDC) at the terminals of the charging socket (8), or otherwise in a determination of a non-sticking (580) of the positive direct current switch (13) or bypass switch (15).

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