METHOD FOR DETECTING THE PRESENCE OR ABSENCE OF A NEUTRAL CONDUCTING LINE IN A MULTIPHASE ALTERNATING ELECTRICAL VOLTAGE SOURCE

Abstract

The invention relates to a method, implemented by a control system of a bidirectional synchronous rectifier connected to a multiphase AC power supply, for detecting the presence or absence of a neutral conductor in the power supply. The method comprises the following steps: a measurement (40) of at least one first quantity relating to a current flowing in a DC voltage bus at the end of a pre-charge phase of the rectifier; a reception (42) of at least one second quantity measured at the end of the pre-charge phase of the rectifier; a comparison (44) of said at least one first quantity measured to a threshold value based on the second quantity measured; and, depending on the result of the comparison (44), a detection (46, 48) of the presence or absence of a neutral conductor in the power supply. Abstract figure: Fig. 2

Description

Title of the invention: METHOD FOR DETECTING THE PRESENCE OR ABSENCE OF A LINE NEUTRAL CONDUCTOR IN A MULTIPHASE ALTERNATING ELECTRICAL VOLTAGE SOURCE

[0001] The invention relates to a method, implemented by a system for controlling a bidirectional synchronous rectifier connected to a multiphase alternating electrical voltage source, for detecting the presence or absence of a neutral conductor line in the multiphase alternating electrical voltage source. Preferably, the multiphase alternating electrical voltage source is a three-phase sinusoidal electrical current power supply network. The invention further relates to an assembly comprising a bidirectional synchronous rectifier and a system for controlling the bidirectional synchronous rectifier configured to implement the steps of such a method. The invention also relates to an electric charger for an electric or hybrid vehicle, comprising such an assembly, as well as to an electric or hybrid vehicle, in particular an automobile, comprising such an electric charger.

[0002] Known in the state of the art are electric chargers for electric or hybrid vehicles, on board such a vehicle and intended to be connected to an electric charging terminal or station, itself connected to a sinusoidal electric voltage source (such as a three-phase electric power supply network) for the electric power supply of the vehicle. Such an electric charger conventionally comprises a bidirectional synchronous rectifier capable of converting a first alternating electric voltage into a second direct electric voltage, a system for controlling the bidirectional synchronous rectifier, as well as a converter configured to convert at high frequency the second direct electric voltage into a third direct electric voltage.The bidirectional synchronous rectifier comprises an active power factor correction stage and a DC voltage bus connected to the output of the active power factor correction stage. The active power factor correction stage allows a power transfer between the sinusoidal electrical voltage source and the DC voltage bus. The synchronous rectifier is called "bidirectional" because it allows the electric current to flow in both directions by controlling reversible controllable electronic switches (as opposed to diodes for example) acting in the rectifier's switching branches, the direction of current flow being a function of the power balance produced by the control loop controller. in voltage acting to maintain the DC voltage bus at its nominal voltage: - if current from the DC to DC converter arrives at the DC voltage bus, the voltage increases and the controller acts to make the current flow in phase opposition to the input voltage in order to discharge the DC voltage bus; - conversely, if the DC to DC converter draws current, the voltage loop controller draws current from the supply grid and the current is in phase with the input voltage.

[0003] The high frequency DC to DC converter (typically a chopper) is connected to the output of the rectifier.

[0004] It is preferable that the electric charger be compatible with any multi-phase alternating current electrical power supply system or network (connected to the electric charging terminal or station), whether or not it has a neutral conductor line. However, the presence or absence of a neutral conductor line in the electrical power supply system or network has a very significant impact on the control strategy of the active correction stage of the bidirectional synchronous rectifier, implemented by the control system. Indeed, depending on whether or not a neutral conductor line is present in the electrical power supply system or network, the control strategies of the active correction stage of the rectifier are completely different in their implementation. For example, when a neutral conductor line is present, a phase-by-phase control strategy of the "a, b, c" type is typically used.On the contrary, when the neutral conductor line is absent, a vector control of the "dqO" type is advantageously used. Furthermore, when the neutral conductor line is absent from the power supply network, the rectifier control strategy implemented by the control system must include special functions, which become useless when the neutral conductor line is present (thereby unnecessarily increasing the computational load when no means of detecting the presence or absence of the neutral conductor line is provided). Among such special functions, we can notably cite: . - compensation for the homopolar component of the electric current; and - an injection of the third harmonic of the current to allow the starting the active correction stage of the bidirectional synchronous rectifier, and to allow the high-frequency converter to operate in boost mode.

[0005] Last but not least, load balancing from one phase to another is not possible when the neutral conductor line is not connected to the electrical charger, whereas this functionality must be provided when the neutral conductor line is connected to the electric charger (in order to comply with regulatory requirements).

[0006] However, until now, nothing obliges the electrical charging terminal or station to provide the electrical charger with information relating to the presence or absence of a neutral conductor line in the multi-phase alternating electrical voltage source. There is therefore a need to be able to have, at the level of the electrical charger and in particular at the level of the bidirectional synchronous rectifier, information as to the presence or absence of a neutral conductor line in the multi-phase alternating electrical voltage source.Furthermore, such information must be available very early after the electrical charger is connected to the electrical supply network, in order to allow the rectifier control system to select the control strategy that will be used, to activate or not special functions such as compensation of the homopolar component and injection of the third harmonic of the current which are necessary at the very beginning of the charging phase in order to supply the active power factor correction stage of the rectifier, and to authorize or not the balancing of the load from one phase to another.

[0007] A degraded solution that is used today is to assume that the neutral conductor line is always absent in the multi-phase AC electrical voltage source. Thus, the electrical charger always operates as a "neutral-less" electrical charger. However, this solution has the main disadvantage that such an electrical charger cannot handle the maximum power that can be drawn from the phases of the voltage source, phase by phase.However, such a functionality can prove particularly useful, for example, in a context where it is necessary to complete the phases independently of each other (if necessary by unbalancing them), allowing faster charging, or to carry out rebalancing of the power supply network (from one phase to another), or to allow distribution of the power seen, balancing and homogenization within the active power factor correction stage of the rectifier in order to slow down the aging of the components.

[0008] The aim of the invention is to overcome the drawbacks of the prior art by proposing a method, implemented by a control system of a bidirectional synchronous rectifier connected to a multi-phase alternating electrical voltage source, for detecting the presence or absence of a neutral conductor line in the multi-phase alternating electrical voltage source, which allows precise detection by the control system of the presence or absence of a neutral conductor line, while being robust to variations in amplitude and frequency of the electrical voltage supplied by the voltage source.

[0009] To do this, the invention thus relates, in its broadest acceptance, to a method, implemented by a control system of a bidi synchronous rectifier rectional connected to a multi-phase alternating electric voltage source, for detecting the presence or absence of a neutral conductor line in the multi-phase alternating electric voltage source, the bidirectional synchronous rectifier comprising a neutral input terminal capable of being connected to a neutral conductor line of the multi-phase alternating electric voltage source, an active power factor correction stage and a direct voltage bus connected to the output of the active power factor correction stage, the active power factor correction stage being provided with several electronic switching branches, at least one half-branch of each of the electronic switching branches comprising at least one switching member, the number of electronic switching branches being equal to the number of phases in the multi-phase alternating electric voltage source,the direct voltage bus comprising two half-branches connected in series at an intermediate terminal, said intermediate terminal being connected to the neutral input terminal, the control system comprising means for measuring at least one quantity relating to a current capable of circulating in the direct voltage bus, the method comprising the following steps: , - a step of measuring at least a first quantity relating to a current flowing in the direct voltage bus at the end of a pre-charging phase of the bidirectional synchronous rectifier, during which no switching member is controlled by the control system, said measuring step providing a first measured quantity; - a step of receiving at least a second quantity measured at the end of the pre-charging phase of the bidirectional synchronous rectifier; - a step of comparing said at least one first measured quantity to a threshold value based on said at least one second measured quantity; and - depending on the result of the comparison, a step of detecting the presence or absence of a neutral conductor line in the multi-phase alternating electric voltage source.

[0010] Thanks to the detection method according to the invention, the control system of the bidirectional synchronous rectifier is capable of autonomously and precisely determining whether a neutral conductor line is present in the multiphase alternating electric voltage source, and this without any communication with a possible terminal or electric charging station connected to the voltage source. The detection method according to the invention is also robust to variations in amplitude and frequency of the electric voltage supplied by the voltage source; and the detection can advantageously be carried out by comparing the measured quantity to both a relative threshold and an absolute threshold. The method can furthermore also be used for a possible plausibility check regarding the presence of a neutral conductor line, which would possibly be provided by an electric charging station or terminal connected to the voltage source. The method can finally be easily adapted to different types of hardware configurations and to different types of available acquisitions: for example, detection based on current (by comparison with the current frequency), on voltage, or on both at the same time.

[0011] According to a first embodiment of the invention, said at least one first measured quantity is the amplitude and / or the frequency of the voltage in the DC voltage bus at the end of the pre-charge phase of the bidirectional synchronous rectifier, and said at least one second measured quantity is the effective amplitude Ueffi and / or the frequency fi of the voltage supplied by the multi-phase AC electrical voltage source at the end of the pre-charge phase of the bidirectional synchronous rectifier, said at least one second measured quantity being supplied by a third-party measuring system. This first embodiment of the invention is advantageous when a measurement of the effective amplitude and / or the frequency of the voltage supplied by the multi-phase AC electrical voltage source is available for the rectifier control system.

[0012] Preferably, during the step of comparing said at least one first measured quantity with a threshold value, if said at least one first measured quantity is the voltage in the DC voltage bus at the end of the pre-charging phase of the bidirectional synchronous rectifier, the voltage threshold value is between a first value equal to ^3 Ue ff i ct a second value equal to 2.1^2 .Ueff ^ ct is preferably equal to 0.5^2 + \l3 j\l2.Ueffi '■> eh if said at least one first measured quantity is the frequency of the voltage in the DC voltage bus at the end of the pre-charge phase of the bidirectional synchronous rectifier, the frequency threshold value is between a first value equal to 3. / t and a second value equal to 6. / and is preferably equal to 4.5 /

[0013] According to a particular technical characteristic of this first embodiment, if said at least one first measured quantity is the voltage in the DC voltage bus at the end of the pre-charge phase of the bidirectional synchronous rectifier, the presence of a neutral conductor line in the multi-phase AC electrical voltage source is detected if, during the comparison step, the measured value of the voltage in the DC voltage bus at the end of the pre-charge phase is greater than said voltage threshold value; and, if said at least one first measured quantity is the frequency of the voltage in the DC voltage bus at the end of the pre-charge phase of the bidirectional synchronous rectifier, the presence of a neutral conductor line in the multi-phase AC electrical voltage source is detected if, during the comparison step, the measured value of the frequency of the voltage in the DC voltage bus at the end of the pre-charge phase is lower than said frequency threshold value.

[0014] According to a second embodiment of the invention, the bidirectional synchronous rectifier further comprises a controllable electronic switch connected between the neutral input terminal and the intermediate terminal, and capable of being controlled by the control system, and the step of measuring at least a first quantity relating to a current flowing in the DC voltage bus at the end of the pre-charging phase of the bidirectional synchronous rectifier comprises a first sub-step during which the electronic switch is controlled to be in the open state, and said at least a first measured quantity is the voltage in the DC voltage bus during this first sub-step, and a second sub-step during which the electronic switch is controlled to be in the closed state,said at least one second quantity measured at the end of the pre-charging phase of the bidirectional synchronous rectifier being the voltage in the DC voltage bus during this second sub-step. This second embodiment of the invention is advantageous when no measurement of the effective amplitude and the frequency of the voltage supplied by the multi-phase AC electrical voltage source is available for the rectifier control system. In this second embodiment, in fact, the detection of the presence or absence of a neutral conductor line in the multi-phase AC electrical voltage source is independent of the value of the effective amplitude and the frequency of the voltage supplied by the voltage source.

[0015] According to a particular technical characteristic of this second embodiment, the presence of a neutral conductor line in the multi-phase alternating electrical voltage source is detected if, during the comparison step, the measured value of the voltage in the direct voltage bus during the first sub-step is distinct from the measured value of the voltage in the direct voltage bus during the second sub-step.

[0016] The invention also relates to an assembly comprising a bidirectional synchronous rectifier and a system for controlling the bidirectional synchronous rectifier, the bidirectional synchronous rectifier being capable of being connected to a multiphase alternating electrical voltage source and comprising a neutral input terminal capable of being connected to a neutral conductor line of the multiphase alternating electrical voltage source, an active power factor correction stage and a direct voltage bus connected to the output of the active power factor correction stage, the active power factor correction stage being provided with several electronic switching branches, at least one half-branch of each of the electronic switching branches comprising at least one switching member. mutation, the number of electronic switching branches being equal to the number of phases in the multi-phase alternating electric voltage source, the direct voltage bus comprising two half-branches connected in series at an intermediate terminal, said intermediate terminal being connected to the neutral input terminal, the control system comprising means for measuring at least one quantity relating to a current capable of circulating in the direct voltage bus, the control system of the bidirectional synchronous rectifier being configured to implement the steps of a method for detecting the presence or absence of a neutral conductive line in the multi-phase alternating electric voltage source as described above.

[0017] The invention also relates to an electric charger for an electric or hybrid vehicle intended to be connected to a terminal or an electric charging station connected to a multi-phase alternating electric voltage source, for the electrical supply of said electric or hybrid vehicle, the electric charger comprising an assembly as described above.

[0018] The invention also relates to an electric or hybrid vehicle, in particular an automobile, comprising an electric charger as described above.

[0019] Embodiments of the present invention will be described below, by way of non-limiting examples, with reference to the appended figures in which: - [Fig.l] is a schematic representation of an assembly comprising a bidirectional synchronous rectifier and a rectifier control system, the control system being configured to implement the steps of a detection method according to the present invention; - [Fig.2] is a flowchart representing a detection method according to a first embodiment of the present invention, implemented by the control system of [Fig.l]; - [Fig.3] is a flowchart representing a detection method according to a second embodiment of the present invention, implemented by a system for controlling an assembly according to the invention.

[0020] With reference to [Fig.l] there is illustrated an assembly 2 comprising a bidirectional synchronous rectifier 4 and a system 6 for controlling the bidirectional synchronous rectifier 4. The assembly 2 is connected on the one hand to a multiphase alternating electrical voltage source 7 (such as for example a three-phase electrical supply network with neutral NI in the particular embodiment of [Fig.l]) providing a multiphase alternating electrical voltage (preferably sinusoidal), and on the other hand to a load 8 delivering between its terminals direct electrical voltage U2. In the particular embodiment of [Fig.l], the three-phase electrical supply network 7 comprises, in addition to the neutral conductor line NI, three lines phase conductors PI, P2, P3. However, it happens that the three-phase power supply network 7 does not have a neutral conductor line, but only phase conductor lines PI, P2, P3 (this configuration is not shown in the figures).

[0021] The assembly 2 is typically installed within an electric or hybrid motor vehicle, more precisely within an electric charger intended to be connected to an electric charging terminal or station, itself connected to the alternating electric voltage source 7, for the electrical supply of the vehicle (neither the vehicle, nor the charging terminal or station, nor the charger as a whole being shown in the figures for reasons of clarity). Preferably, the direct electric voltage U2 makes it possible to supply an electric storage battery of the vehicle, after transformation by one or more other stage(s) of the electric charger (such as for example a step-down and step-up chopper). The assembly 2 thus supplies the direct electric voltage U2 on an output bus 5 to which the load 8 is connected, the value of this direct electric voltage U2 being for example of the order of 400 Vdc or 800 Vdc.

[0022] In addition to the output bus 5, the bidirectional synchronous rectifier 4 also comprises a neutral input terminal 9 and an active power factor correction stage 10, the output bus 5 being connected to the output of the active power factor correction stage 10 via at least one resistor (in this case via two resistors RI, R2 in the embodiment example of [Fig.l]). Preferably, and as illustrated in [Fig.l], the bidirectional synchronous rectifier 4 also comprises an electromagnetic interference filtering stage 12, the active power factor correction stage 10 being connected to the output of the electromagnetic interference filtering stage 12 via three inductors L1, L2, L3 and three resistors R3, R4, R5. The neutral input terminal 9 is then an input terminal of the electromagnetic interference filtering stage 12.Each pair of an inductance L1, L2, respectively L3, and a resistor R3, R4, respectively R5, corresponds to a distinct phase conductive line PI, P2, P3, the inductance L1, L2, L3 and the resistor R3, R4, R5 of each pair being connected in series. In the particular embodiment shown in [Fig.l], the bidirectional synchronous rectifier 4 also comprises a controllable electronic switch 14. In a variant not shown in the figures, the bidirectional synchronous rectifier 4 may not comprise a controllable electronic switch 14.

[0023] In the particular embodiment shown in [Fig.l], two third-party measuring systems 1 IA, 1 IB make it possible to measure respectively the effective amplitude Ueffi and the frequency fi of the voltage supplied by the alternating electric voltage source 7. As illustrated in [Fig.l], the system 11B for measuring the frequency fi of the current delivered by the alternating electric voltage source 7 is for example connected between the active power factor correction stage 10 and the electromagnetic disturbance filtering stage 12. The system 11B for measuring the frequency fi of the current is for example a phase-locked loop measuring system. The two third-party measuring systems 11 A, 11B are connected to the control system 6, making it possible to provide their measurements to this system 6.

[0024] The neutral input terminal 9 is capable of being connected to the neutral conductive line NI of the alternating electrical voltage source 7, when the connection between the electric charger of the vehicle and the terminal or the electric charging station is made. When the alternating electrical voltage source 7 does not have a neutral conductive line (which the assembly 2 embedded in the electric charger does not “know”, the neutral input terminal 9 is not physically connected to any element).

[0025] The electromagnetic disturbance filtering stage 12 is suitable for being connected to the alternating electrical voltage source 7, when the connection between the electric charger of the vehicle and the electric charging terminal or station is made. The electromagnetic disturbance filtering stage 12 comprises as many input terminals as there are phase conductive lines PI, P2, P3 in the three-phase electrical supply network 7. The electromagnetic disturbance filtering stage 12 comprises as many output terminals as there are phase conductive lines PI, P2, P3 in the three-phase electrical supply network 7.

[0026] The active power factor correction stage 10 comprises several electronic switching branches 16, 18, 20, in this case three electronic switching branches 16, 18, 20 in the particular embodiment of [Fig. 1]. Each electronic switching branch 16, 18, 20 corresponds to a separate phase conductive line PI, P2, P3 of the three-phase electrical power supply network 7.

[0027] Each electronic switching branch 16, 18, 20 comprises two switching half-branches 16A, 16B; 18A, 18B; 20A, 20B connected in series at an intermediate terminal 22, 24, 26. Each intermediate terminal 22, 24, 26 is connected to one end of one of the inductances L1, L2, L3. Each switching half-branch 16A, 16B, 18A, 18B, 20A, 20B comprises a switching member 28. In a variant not shown, each half-branch 16A, 16B, 18A, 18B, 20A, 20B comprises a number N2 of switching members 28, N2 being an integer greater than or equal to two. The switching of the switching members 28 is controlled by a control unit 29 of the control system 6. The control unit 29 is also capable of controlling the switching of the controllable electronic switch 14, as will be described later.

[0028] As known per se, each switching member 28 is bidirectional in current and unidirectional in voltage. Each switching member 28 comprises a controllable electronic switch 30 and a diode 32 connected in antiparallel thus ensuring bidirectional current flow paths. Each switch 30 is for example formed from an insulated gate bipolar transistor, also called an IGBT transistor (from the English “Insulated Gate Bipolar Transistor”). All the IGBT transistors 30 are, for example, identical. The gate of each IGBT transistor 30 is connected to the control system 6 to receive a corresponding control signal.Alternatively, the IGBT transistor 30 is replaced by any semiconductor electronic component comprising a control electrode and two conduction electrodes, such as a bipolar transistor, a field effect transistor, a thyristor, a gate-switched thyristor, an IGCT thyristor (from the English "Insulated Gate Commutated Thysistor"), or an MCT thyristor (from the English "MOS Controlled Thyristor") for example.

[0029] The output bus 5 comprises two half-branches 5A, 5B connected in series at an intermediate terminal 34. In the particular embodiment of [Fig.l], each half-branch 5A, respectively 5B comprises a capacitor C1, respectively C2 and a resistor R6, respectively R7 connected in series. Preferably, the capacitance value of the capacitor C1 is equal to the capacitance value of the capacitor C2, in order to balance the output bus 5. The intermediate terminal 34 is connected to the neutral input terminal 9. In the particular embodiment shown in [Fig.l], the intermediate terminal 34 is connected to the neutral input terminal 9 via the controllable electronic switch 14 which is connected in series between the neutral input terminal 9 and the intermediate terminal 34.

[0030] In addition to the control unit 29, the control system 6 comprises means 26 for measuring at least one quantity relating to a current capable of flowing in the DC voltage bus 5. In a first embodiment of the invention, corresponding to the configuration shown in [Fig. 1], the measuring means 26 are configured to measure the amplitude and / or the frequency of the voltage in the DC voltage bus 5 at the end of a pre-charging phase of the bidirectional synchronous rectifier 4 (such a phase being a natural or passive pre-charging phase, during which no switching member 28 is controlled by the control system 6). Preferably, the measuring means 26 are configured to measure both the amplitude and the frequency of the voltage in the DC voltage bus 5 at the end of the pre-charging phase of the bidirectional synchronous rectifier 4.In a second embodiment of the invention, corresponding to a configuration not shown in the figures for which the control system 6 does not have the measurement of the effective amplitude Ueffi nor of the frequency fi of the voltage supplied by the source of . alternating current voltage 7 (no third-party measuring systems 11 A, 11B), the measuring means 26 are configured to measure the voltage in the direct current voltage bus 5 at the end of the pre-charging phase of the bidirectional synchronous rectifier 4.

[0031] The method for detecting the presence or absence of a neutral conductor line in the multiphase alternating electric voltage source 7, implemented by the system 6 for controlling the bidirectional synchronous rectifier 4, will now be described.

[0032] It is assumed that the bidirectional synchronous rectifier 4 is initially in a pre-charge phase, during which no switching member 28 is controlled by the control system 6 (the rectifier 4 then operates as a diode bridge, and the electrical voltage delivered on the DC voltage bus 5 is gradually and naturally brought to an intermediate voltage value). After the pre-charge phase, the bidirectional synchronous rectifier 4 then enters a “conventional” charging phase during which the control system 6 controls the switching of the switching members 28 in the branches 16, 18, 20 (and the electrical voltage delivered on the DC voltage bus 5 is gradually brought from its intermediate value at the end of the pre-charge phase to its nominal value), such a charging phase not being detailed subsequently.

[0033] With reference to [Fig. 2], the method in the first embodiment of the invention (corresponding to the configuration shown in [Fig. 1]) comprises an initial step 40 of measuring, by the control system 6, the amplitude and / or the frequency of the voltage in the DC voltage bus 5 at the end of the precharging phase of the bidirectional synchronous rectifier 4.

[0034] In this first embodiment of the invention, the method comprises a following step 42 during which the system 6 for controlling the bidirectional synchronous rectifier 4 receives the measurement of the effective amplitude Ueffi and / or the frequency fi of the voltage supplied by the alternating electrical voltage source 7 at the end of the pre-charging phase of the rectifier 4, these two measurements being supplied by the third-party measurement systems 11A, 11B.

[0035] The method then comprises a following step 44 during which the system 6 for controlling the bidirectional synchronous rectifier 4 compares the measured value of the amplitude and / or frequency of the voltage in the DC voltage bus 5 at the end of the pre-charging phase of the bidirectional synchronous rectifier 4 with a threshold value. For the comparison of the voltage values, the voltage threshold value is typically between a first value equal to and a second value equal to 2.^2.£7eyyp and is preferably equal to 0.5.(2 + For the comparison of frequency values, the frequency threshold value is typically between a first value equal to 3. / and a second value equal to 6. / and is preferably equal to 4.5. /

[0036] At the end of the comparison step 44, if the measured value of the voltage in the DC voltage bus 5 at the end of the pre-charging phase of the bidirectional synchronous rectifier 4 is greater than the voltage threshold value and / or if the measured value of the frequency of the voltage in the DC voltage bus 5 at the end of the pre-charging phase of the bidirectional synchronous rectifier 4 is less than the frequency threshold value, then the presence of a neutral conductor line NI in the AC electrical voltage source 7 is detected by the control system 6 during a final step 46 (as is the case in the configuration illustrated in [Fig.l]). Otherwise, the control system 6 detects an absence of a neutral conductor line in the AC electrical voltage source 7, during a final step 58.

[0037] Indeed, when a neutral conductor line NI is present in the AC electrical voltage source 7 (as is the case in the configuration illustrated in FIG. 1), the voltage in the DC voltage bus 5 at the end of the pre-charge phase of the bidirectional synchronous rectifier 4 is substantially equal to 2.\l2.Ueff i ct the frequency of the voltage in the DC voltage bus 5 at the end of the pre-charge phase of the bidirectional synchronous rectifier 4 is substantially equal to 3. / When no neutral conductor line is present in the AC electrical voltage source 7, the voltage in the DC voltage bus 5 at the end of the pre-charge phase of the bidirectional synchronous rectifier 4 is substantially equal to ^3.>^2.Ueff i ct the frequency of the voltage in the DC voltage bus 5 at the end of the pre-charge phase of the bidirectional synchronous rectifier 4 is substantially equal to 6. / Thus, by adjusting the voltage and frequency threshold values ​​between these two pairs of limit values ​​(preferably "halfway" between these limit values), it is possible to precisely detect the presence or absence of a neutral conductor line in the AC electrical voltage source 7. .

[0038] With reference to [Fig. 3], the method in the second embodiment of the invention comprises an initial step 50 of measurement, by the control system 6, of the voltage in the DC voltage bus 5 at the end of the pre-charge phase of the bidirectional synchronous rectifier 4. More precisely, the initial measurement step 50 comprises a first sub-step 50A during which the electronic switch 14 is controlled by the control system 6 to be in the open state, and the control system 6 measures a first voltage value in the DC voltage bus 5 at the end of the pre-charge phase of the bidirectional synchronous rectifier 4. The initial measurement step 50 then comprises a second sub-step 50B during which the electronic switch 14 is controlled by the control system 6 to be in the open state, and the control system 6 measures a second voltage value in the DC voltage bus 5 at the end of the pre-charge phase of the bidirectional synchronous rectifier 4. the closed state, and the control system 6 measures a second voltage value in the direct voltage bus 5 at the end of the pre-charging phase of the bidirectional synchronous rectifier 4.

[0039] The method then comprises a following step 52 during which the system 6 for controlling the bidirectional synchronous rectifier 4 compares the first voltage value (measured during the first sub-step 50A) with the second voltage value (measured during the second sub-step 50B).

[0040] At the end of the comparison step 52, if the first measured voltage value is distinct from the second measured voltage value, then the presence of a neutral conductive line N1 in the alternating electrical voltage source 7 is detected by the control system 6 during a final step 56. Otherwise, the control system 6 detects an absence of a neutral conductive line in the alternating electrical voltage source 7, during a final step 58.

[0041] Indeed, when a neutral conductive line NI is present in the alternating electrical voltage source 7, the value of the voltage in the direct voltage bus 5 at the end of the pre-charging phase of the bidirectional synchronous rectifier 4 undergoes a sudden “jump” when the electronic switch 14 closes, due to the electrical voltage present on the neutral line NI.

[0042] Thanks to the detection method according to the invention, the system 6 for controlling the bidirectional synchronous rectifier 4 is capable of determining autonomously and precisely whether a neutral conductor line N1 is present in the multiphase alternating electrical voltage source 7, and this without any communication with a possible electrical charging terminal or station connected to the voltage source 7.

Claims

1. Claims Method, implemented by a system (6) for controlling a bidirectional synchronous rectifier (4) connected to a multiphase alternating electric voltage source (7), for detecting the presence or absence of a neutral conductor line (NI) in the multiphase alternating electric voltage source (7), the bidirectional synchronous rectifier (4) comprising a neutral input terminal (9) capable of being connected to a neutral conductor line (NI) of the multiphase alternating electric voltage source (7), an active power factor correction stage (10) and a direct voltage bus (5) connected to the output of the active power factor correction stage (10), the active power factor correction stage (10) being provided with several electronic switching branches (16, 18, 20), at least one half-branch (16A, 16B, 18A, 18B, 20A, 20B) of each of the electronic switching branches (16, 18,20) comprising at least one switching member (28), the number of electronic switching branches (16, 18, 20) being equal to the number of phases (PI, P2, P3) in the multiphase alternating electric voltage source (7), the direct voltage bus (5) comprising two half-branches (5A, 5B) connected in series at an intermediate terminal (34), said intermediate terminal (34) being connected to the neutral input terminal (9), the control system (6) comprising means for measuring at least one quantity relating to a current capable of circulating in the direct voltage bus (5), characterized in that the method comprises the steps of:, - a step of measuring (40; 50) at least a first quantity relating to a current flowing in the direct voltage bus (5) at the end of a pre-charging phase of the bidirectional synchronous rectifier (4), during which no switching member (28) is controlled by the control system (6), said measuring step (40; 50) providing a first measured quantity; - a reception step (42; 50B) of at least a second quantity measured at the end of the pre-charging phase of the bidirectional synchronous rectifier (4); - a step of comparing (44; 52) said at least one first measured quantity to a threshold value based on said at least one second measured quantity; and - depending on the result of the comparison (44; 52), a step of detecting (46, 48; 56, 58) the presence or absence of a neutral conductor line (NI) in the multi-phase alternating electric voltage source (7).

2. Method according to claim 1, characterized in that said at least one first measured quantity is the amplitude and / or the frequency of the voltage in the direct voltage bus (5) at the end of the pre-charging phase of the bidirectional synchronous rectifier (4), and in that said at least one second measured quantity is the effective amplitude Ueffi and / or the frequency fi of the voltage supplied by the multi-phase alternating electric voltage source (7) at the end of the pre-charging phase of the bidirectional synchronous rectifier (4), said at least one second measured quantity being supplied by a third-party measuring system (11 A, 11B).

3. Method according to claim 2, characterized in that, during the step of comparing (44) said at least one first measured quantity with a threshold value, if said at least one first measured quantity is the voltage in the DC voltage bus (5) at the end of the pre-charging phase of the bidirectional synchronous rectifier (4), the voltage threshold value is between a first value equal to ^3.^2 .Ueffl and a second value equal to 2.^2.1 / ^^ and is preferably equal to 0.5.(2+ and, if said at least one first measured quantity is the frequency of the voltage in the DC voltage bus (5) at the end of the pre-charging phase of the bidirectional synchronous rectifier (4), the frequency threshold value is between a first value equal to 3. / and a second value equal to 6. / and is preferably equal to 4.

5. /

4. Method according to claim 3, characterized in that, if said at least one first measured quantity is the voltage in the DC voltage bus (5) at the end of the pre-charging phase of the bidirectional synchronous rectifier (4), the presence of a neutral conductor line (NI) in the multi-phase AC electrical voltage source (7) is detected if, during the comparison step (44), the measured value of the voltage in the DC voltage bus (5) at the end of the pre-charging phase is greater than said voltage threshold value; and, if said at least one first measured quantity is the frequency of the voltage in the direct voltage bus (5) at the end of the pre-charging phase of the bidirectional synchronous rectifier (4), the presence of a neutral conductor line (NI) in the multi-phase alternating electric voltage source (7) is detected if, during the comparison step (44), the measured value of the frequency of the voltage in the direct voltage bus (5) at the end of the pre-charging phase is lower than said frequency threshold value.

5. Method according to claim 1, characterized in that the bidirectional synchronous rectifier (4) further comprises a controllable electronic switch (14) connected between the neutral input terminal (9) and the intermediate terminal (34), and capable of being controlled by the control system (6), and in that the step (50) of measuring at least a first quantity relating to a current flowing in the DC voltage bus (5) at the end of the pre-charging phase of the bidirectional synchronous rectifier (4) comprises a first sub-step (50A) during which the electronic switch (14) is controlled to be in the open state, and said at least a first measured quantity is the voltage in the DC voltage bus (5) during this first sub-step (50A), and a second sub-step (50B) during which the electronic switch (14) is controlled to be in the closed state,said at least one second quantity measured at the end of the pre-charging phase of the bidirectional synchronous rectifier (4) being the voltage in the direct voltage bus (5) during this second sub-step (50B).,

6. Method according to claim 5, characterized in that the presence of a neutral conductor line (NI) in the multi-phase alternating electric voltage source (7) is detected if, during the comparison step (52), the measured value of the voltage in the direct voltage bus (5) during the first sub-step (50A) is distinct from the measured value of the voltage in the direct voltage bus (5) during the second sub-step (50B).

7. Assembly (2) comprising a bidirectional synchronous rectifier (4) and a system (6) for controlling the bidirectional synchronous rectifier (4), the bidirectional synchronous rectifier (4) being capable of being connected to a multiphase alternating electric voltage source (7) and comprising a neutral input terminal (9) capable of being connected to a neutral conductive line (NI) of the alternating electric voltage source

8.

9. multiphase (7), an active power factor correction stage (10) and a direct voltage bus (5) connected to the output of the active power factor correction stage (10), the active power factor correction stage (10) being provided with several electronic switching branches (16, 18, 20), at least one half-branch (16A, 16B, 18A, 18B, 20A, 20B) of each of the electronic switching branches (16, 18, 20) comprising at least one switching member (28), the number of electronic switching branches (16, 18, 20) being equal to the number of phases (PI, P2, P3) in the multiphase alternating electric voltage source (7), the direct voltage bus (5) comprising two half-branches (5A, 5B) connected in series at an intermediate terminal (34), said intermediate terminal (34) being connected to the terminal neutral input (9),the control system (6) comprising means for measuring at least one quantity relating to a current capable of circulating in the direct voltage bus (5), characterized in that the system (6) for controlling the bidirectional synchronous rectifier (4) is configured to implement the steps of a method for detecting the presence or absence of a neutral conductor line (NI) in the multiphase alternating electric voltage source (7) according to any one of claims 1 to 6., Electric charger for an electric or hybrid vehicle intended to be connected to a terminal or an electric charging station connected to a multi-phase alternating electric voltage source (7), for the electrical supply of said electric or hybrid vehicle, characterized in that it comprises an assembly (2) according to claim 7. Electric or hybrid vehicle, in particular an automobile, characterized in that it comprises an electric charger according to claim 8.

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