SYSTEM FOR CONVERTING A FIRST ELECTRICAL VOLTAGE INTO A SECOND ELECTRICAL VOLTAGE COMPRISING AN ACTIVE POWER FACTOR CORRECTION STAGE

Abstract

The invention relates to a system (2) for converting a first electrical voltage (U1) into a second electrical voltage (U2) comprising an electromagnetic disturbance filtering stage (4) and an active power factor correction stage (6) connected to the output of the electromagnetic disturbance filtering stage (4), the active power factor correction stage (6) comprising a bidirectional synchronous rectifier bridge (16) and at least one high-frequency switching electronic branch (18) connected to the output of the rectifier (16) via at least one main inductor (8), the number of high-frequency switching electronic branch(es) being equal to the number of main inductors, the electrical conversion system (2) further comprising a saturable inductor (9) with a saturation current threshold,the inductance value of said inductance (9) when it is not saturated being substantially equal to the inductance value of the main inductance (8). Abstract figure: Fig. 1,

Description

Title of the invention: SYSTEM FOR CONVERTING A FIRST ELECTRICAL VOLTAGE INTO A SECOND ELECTRICAL VOLTAGE COMPRISING AN ACTIVE POWER FACTOR CORRECTION STAGE

[0001] The invention relates to a system for converting a first electrical voltage into a second electrical voltage, comprising an electromagnetic disturbance filtering stage and an active power factor correction stage. Preferably, the first electrical voltage is an alternating electrical voltage (preferably sinusoidal) from a single-phase electrical supply network, and the second electrical voltage is a direct electrical voltage. The invention also relates to an electrical charger for an electric or hybrid vehicle, comprising such an electrical conversion system, as well as to an electric or hybrid vehicle, in particular an automobile, comprising such an electrical 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 a terminal or to an electric charging station, itself connected to a sinusoidal electric voltage source (such as a single-phase, two-phase or three-phase electric power supply network) for the electric power supply of the vehicle. Such an electric charger conventionally comprises a system for converting a first alternating electric voltage into a second rectified electric voltage, as well as a converter configured to convert at high frequency the second rectified electric voltage into a third direct electric voltage (this third direct electric voltage being used for example for an electric storage battery of the vehicle). The high-frequency converter (typically a chopper) is connected to the output of the conversion system.

[0003] The conversion system typically comprises an electromagnetic disturbance filtering stage and an active power factor correction stage connected to the output of the electromagnetic disturbance filtering stage via at least one main inductor.

[0004] The electromagnetic disturbance filtering stage is connected to the sinusoidal electrical voltage source, and makes it possible to filter harmonics generating electromagnetic disturbances. As known per se, the active power factor correction stage comprises a bidirectional synchronous rectifier bridge controlled at low frequency and a boost chopper controlled at high frequency. The low frequency corresponds in practice to the frequency of the voltage supplied by the network single-phase, two-phase or three-phase power supply. The active power factor correction stage makes it possible to absorb a current as sinusoidal as possible from the power supply network with a minimal phase shift (preferably zero) between the fundamental of the absorbed current and the mains voltage. The function of this stage is thus to take a "quasi-sinusoidal" electric current using a current control loop (implemented in particular via the main inductor). The principle of sinusoidal sampling then consists of "forcing" the current flowing in a bus of the main inductor of the conversion system to follow a rectified sinusoidal reference, by controlling the closing and opening of the power switches controlled in the electronic switching branches.The active power factor correction stage thus supplies power to a capacitive load as well as to the vehicle battery, and makes it possible to actively correct the current absorbed by this load and this battery (using the current control loop).

[0005] The electromagnetic disturbance filtering stage is provided with a line connected on the one hand to a neutral conductor line and on the other hand to an intermediate terminal located in the middle of the low-frequency switching electronic branch of the active power factor correction stage. When the active power factor correction stage implements a “bidirectional synchronous rectifier” type topology, this low-frequency switching electronic branch makes it possible to process regular alternations in the input electrical voltage signal (positive as well as negative alternations), as well as to allow rectification of the voltage. The low-frequency switching electronic part (bidirectional synchronous rectifier bridge) has a switching frequency substantially equal to that of the input electrical power supply network (for example 50 Hz).The high-frequency switching electronic part (boost chopper) ensures high-frequency switching of the input electric current, which makes it possible to generate an input sinusoidal wave in phase with the voltage of the input power supply network, as well as high-frequency ripples intended to be filtered by the electromagnetic disturbance filtering stage.

[0006] In the active power factor correction stage, the input electrical current is thus in phase with the input electrical voltage. However, for certain topologies of the active power factor correction stage (including the “mid-point cascode bidirectional synchronous rectifier” type topology), the input electrical current (from the electrical supply network) is not controlled when the input electrical voltage is close to zero. This is due to the fact that a margin must be maintained relative to the accuracy of the measurement when the voltage of the electrical supply network passes through zero volts. to switch the low-frequency switches at the right time. It then becomes necessary to impose a latency time because without this it is not possible to ensure perfect synchronization between the input electrical current and the input electrical voltage around their zero values. An additional latency time is also necessary to allow sufficient switching time for the low-frequency switching electronic branch, the duration of this additional latency time being generally longer than that(s) affecting the high-frequency switching electronic branch(es).

[0007] Several problems are then likely to appear: - first of all, the switching of the low-frequency switching electronic branch is likely to cause a sudden voltage variation on the “ground” line of the step-up chopper stage, which generates significant disturbances within the system; - then all the control electronics of the conversion system (in particular the active power factor correction stage) are subject to significant high-frequency noise, due to the aforementioned sudden voltage variation of the low-frequency switching electronic branch; - finally, the presence of the main inductance means that when the input electric current and the input electric voltage are close to their zero values, the inductance then plays the role of a passive element which is added to the other passive elements of the electromagnetic disturbance filtering stage and unbalances the latter.

[0008] These three cumulative problems cause a significant imbalance within the electromagnetic disturbance filtering stage, between the phase line(s) and the neutral line. This harms the performance of the electrical conversion system.

[0009] The aim of the invention is to overcome the drawbacks of the prior art by proposing a system for converting a first electrical voltage into a second electrical voltage comprising an electromagnetic disturbance filtering stage and an active power factor correction stage, which makes it possible not to unbalance the electromagnetic disturbance filtering stage when the input electrical current and the input electrical voltage are close to their zero values, as well as to reduce the disturbances on the neutral line of the system, and this without affecting the nominal behavior of the system when the low-frequency controllable electronic switches are not switching.

[0010] To do this, the invention thus relates, in its broadest sense, to a system for converting a first electrical voltage into a second electrical voltage comprising an electromagnetic disturbance filtering stage and an active power factor correction stage connected to the output of the stage of filtering of electromagnetic disturbances, the conversion system being provided with two output terminals, the electromagnetic disturbance filtering stage being suitable for being connected to an alternating electrical voltage source comprising a neutral conductive line and at least one phase conductive line, and comprising a first output terminal connected to the neutral conductive line and at least one second output terminal connected to said at least one phase conductive line, the active power factor correction stage comprising a bidirectional synchronous rectifier bridge and at least one high-frequency electronic switching branch connected to the output of the bidirectional synchronous rectifier bridge via at least one main inductor, said at least one high-frequency electronic switching branch being further connected between the two output terminals of the conversion system,the number of high-frequency switching electronic branch(es) being equal to the number of main inductance(s), the bidirectional synchronous rectifier bridge comprising four first switching members and a microcontroller, each first switching member being provided with a low-frequency controllable electronic switch, the bidirectional synchronous rectifier bridge comprising two input terminals and two output terminals, the microcontroller being provided with four control terminals and being configured to carry out acquisitions from the two input terminals and the two output terminals of the bidirectional synchronous rectifier bridge, a first input terminal of the bidirectional synchronous rectifier bridge being connected to the first output terminal of the electromagnetic interference filtering stage,a second input terminal of the bidirectional synchronous rectifier bridge being connected to said at least one second output terminal of the electromagnetic interference filtering stage, a first output terminal of the bidirectional synchronous rectifier bridge being connected to said at least one main inductor, each control terminal of the microcontroller being connected to the control electrode of a separate electronic switch, a first electronic switch being connected between the first input terminal and the first output terminal of the bidirectional synchronous rectifier bridge, a second electronic switch being connected between the first input terminal and the second output terminal of the bidirectional synchronous rectifier bridge, a third electronic switch being connected between the second input terminal and the second output terminal of the bidirectional synchronous rectifier bridge,a fourth electronic switch being connected between the second input terminal and the first output terminal of the bidirectional synchronous rectifier bridge, said at least one high-frequency electronic switching branch comprising two high-frequency switching half-branches connected in series at an intermediate terminal, said intermediate terminal being connected to the or one of the main inductance(s), each half-com- branch, high frequency mutation of said at least one high frequency switching branch comprising a second switching member provided with a controllable electronic switch, in which the electrical conversion system further comprises a saturable inductor with saturation current threshold, said saturable inductor being connected between the second output terminal of the bidirectional synchronous rectifier bridge and one of the output terminals of the conversion system, the inductance value of said saturable inductor when it is not saturated being substantially equal to the inductance value of said at least one main inductor.

[0011] Such a saturable inductance thus configured and connected in the conversion system makes it possible to balance the main inductance as well as to act as an additional filter on the ground line of the system when the input electric current and the input electric voltage are close to their zero values. Indeed, via such a configuration, the saturable inductance is caused to saturate abruptly if the value of the current flowing through it becomes greater than a current threshold value of the magnetization characteristic of the inductance: the value of this inductance thus saturated then becomes negligible in the circuit, which does not impact the nominal behavior of the system (nominally regulated current) when the low-frequency controllable electronic switches are not switching.Conversely, when the current value becomes lower than the current threshold value of the magnetization characteristic of the inductor (in other words when the input electrical current and the input electrical voltage are close to their zero values, and therefore the inductor is not saturated), the saturable inductor has its nominal value (substantially equal to the inductance value of the main inductor) and acts as an additional filter on the system ground line. The presence of such a saturable inductor in the electrical conversion system thus makes it possible to mitigate the electromagnetic compatibility problems linked to the low-frequency switching of the low-frequency controllable switches, without affecting the nominal behavior of the system when the low-frequency controllable electronic switches are not switching.This results in a completely or almost completely balanced electromagnetic interference filtering stage in terms of filtering.

[0012] Furthermore, compared to using a "conventional" (non-saturable) inductor that would be connected to the same location (i.e. between the second output terminal of the microcontroller and one of the output terminals of the conversion system), using a saturable inductor with a saturation current threshold has the following additional advantages: - a saturable inductance has a reduced volume and an integration facilitated; - a saturable inductance allows the inductance value to be doubled (when it is not saturated), without doubling the size and price of the device; - when the active power factor correction stage comprises several high-frequency switching electronic branches connected in parallel, the presence of a saturable inductor makes it possible to maintain the same behavior for the system as if there were only one high-frequency switching electronic branch (independent behavior and control of the branches); if the inductor were a “classic” inductor (therefore non-saturable), the latter would link the high-frequency branches by the current, which would completely modify the behavior of the system (non-independent behavior and control of the branches) and would in fact make the latter more complex and less efficient; - when the active power factor correction stage has several high-frequency switching electronic branches connected in parallel, a "classic" (non-saturable) inductor would have to hold the sum of all the currents flowing in the high-frequency branches without saturating, and would therefore be much larger in size (and therefore more expensive) compared to a saturable inductor.

[0013] According to a particular technical characteristic of the invention, said saturable inductance comprises a ferromagnetic ferrite material.

[0014] Advantageously, said saturable inductance has a magnetization characteristic whose current threshold value is substantially equal to 1 A. This makes it possible to obtain rapid saturation of the inductance, while maintaining reasonable dimensions for the latter.

[0015] According to a particular technical characteristic of the invention, each electronic switch comprises a semiconductor electronic switching component, such as a transistor or a thyristor.

[0016] According to a particular technical characteristic of the invention, the conversion system is provided with a positive voltage output terminal and a negative voltage output terminal, said saturable inductance being connected between the second output terminal of the bidirectional synchronous rectifier bridge and the negative voltage output terminal of the conversion system.

[0017] According to a particular technical characteristic of the invention, the electromagnetic disturbance filtering stage comprises at least one common mode filtering member and at least one differential mode filtering member. The common mode filtering members make it possible to filter the disturbances between the phase or the neutral on the one hand, and the earth line on the other hand. The differential mode filtering members allow to filter the disturbances between the phase and the neutral. The main inductance and the saturable inductance act on both the common mode and the differential mode.

[0018] The invention also relates to an electric charger for an electric or hybrid vehicle intended to be connected to a terminal or to an electric charging station connected to an alternating electric voltage source, for the electrical supply of said electric or hybrid vehicle, the electric charger comprising a system for converting a first electric voltage into a second electric voltage as described above.

[0019] The invention also relates to an electric or hybrid vehicle, in particular an automobile, comprising an electric charger as described above.

[0020] Embodiments of the present invention will be described below, by way of non-limiting examples, with reference to the single appended figure in which: - [Fig.l] is a schematic representation of an electrical conversion system according to an embodiment of the present invention.

[0021] With reference to [Fig.l] a system 2 for converting a first electrical voltage U1 into a second electrical voltage U2 is illustrated, according to an embodiment of the invention. The electrical conversion system 2 is connected on the one hand to an alternating electrical voltage source (such as for example a single-phase, two-phase or three-phase electrical supply network - such a source not being shown in the figure for reasons of clarity) providing the first electrical voltage U1, and on the other hand to a load 3 delivering between its terminals 7A, 7B the second electrical voltage U2. The alternating electrical voltage source (preferably sinusoidal) conventionally comprises a neutral conductive line NI and at least one phase conductive line (in this case a single phase conductive line PI in the particular embodiment illustrated in [Fig.l] for which the electrical supply network is a single-phase network).The electrical conversion system 2 is typically installed within an electric or hybrid motor vehicle, more precisely within an electrical charger intended to be connected to an electrical charging terminal or station, itself connected to the source of alternating electrical voltage, 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 figure for reasons of clarity). Preferably, the first electrical voltage Ul is an alternating electrical voltage from the single-phase, two-phase or three-phase electrical supply network and the second electrical voltage U2 is a direct electrical voltage making it possible to supply an electrical storage battery of the vehicle, after transformation by one or more other stage(s) of the electrical charger (such as for example a step-down chopper). The conversion system. electrical 2 thus provides the second direct electrical voltage U2 on an output bus 5 to which the load 3 is connected, the value of this second direct electrical voltage U2 being for example of the order of 400 Vdc or 800 Vdc.

[0022] The electrical conversion system 2 comprises an electromagnetic disturbance filtering stage 4 and an active power factor correction stage 6 connected to the output of the electromagnetic disturbance filtering stage 4. The electrical conversion system 2 further comprises two output terminals 7A, 7B between which the load 3 is connected. More precisely, the electrical conversion system 2 comprises a positive voltage output terminal 7A and a negative voltage output terminal 7B.

[0023] The electromagnetic disturbance filtering stage 4 is suitable for being connected to the alternating electric voltage source, when the connection between the electric charger of the vehicle and the electric charging terminal or station is made. The electromagnetic disturbance filtering stage 4 comprises a neutral input terminal 10A, at least one phase input terminal 10B, a neutral output terminal 12A, at least one phase output terminal 12B, at least one common mode filtering member T1, C3, C4, and at least one differential mode filtering member C1, C2, L1, L2. The electromagnetic disturbance filtering stage 4 also comprises a line 14 connected to the ground. In the particular embodiment of [Fig.l], the electromagnetic disturbance filtering stage 4 comprises a neutral input terminal 10A, a single phase input terminal 10B (corresponding to the single phase of the input single-phase alternating voltage), a neutral output terminal 12A, a single phase output terminal 12B (corresponding to the single phase of the input single-phase alternating voltage), three common mode filtering members Tl, C3, C4, and four differential mode filtering members C1, C2, Ll, L2. The common mode filtering members Tl, C3, C4 make it possible to filter the disturbances between the phase or the neutral on the one hand, and the earth line 14 on the other hand. The differential mode filtering members C1, C2, Ll, L2 make it possible to filter the current ripples generated on the main inductor 8 (which will be described later).

[0024] The neutral input terminal 10A is connected to the neutral conductive line NI, and the phase input terminal 10B is connected to the phase conductive line PL. A first differential mode filtering member is a capacitor C1 connected between the neutral input terminal 10A and the phase input terminal 10B. A first common mode filtering member is a common mode coil Tl, one of the terminals of each of the two mutual inductances of which is connected respectively to the neutral input terminal 10A, and to the phase input terminal 10B. A second differential mode filtering member is an inductance Ll connected between the other terminal of one of the two mutual inductances of the common mode coil Tl on the one hand, and the phase output terminal 12B on the other hand. A third differential mode filtering member is an inductor L2 connected between the other terminal of the other mutual inductance of the common mode coil Tl on the one hand, and the neutral output terminal 12A on the other hand. A fourth differential mode filtering member is a capacitor C2 connected between the neutral output terminal 12A and the phase output terminal 12B. A second common mode filtering member is a capacitor C3 connected between the neutral output terminal 12A and the line 14 connected to ground. A third common mode filtering member is a capacitor C4 connected between the phase output terminal 12B and the line 14 connected to ground.

[0025] Thus, the neutral output terminal 12A is connected to the neutral conductive line NI via the inductance L2 and the common mode coil Tl, and the phase output terminal 12B is connected to the phase conductive line PI via the inductance L1 and the common mode coil Tl.

[0026] It should be noted that the value of the inductance L1 is equal to the value of the inductance L2, in order to balance the electromagnetic disturbance filtering stage 4 and not to disturb the action of the first, second and third common mode filtering members T1, C3, C4.

[0027] The active power factor correction stage 6 comprises a bidirectional synchronous rectifier bridge 16 and at least one high-frequency switching electronic branch 18 connected to the output of the bidirectional synchronous rectifier bridge 16 via at least one main inductor 8 and one saturable inductor 9 with a saturation current threshold. In the particular embodiment of [Fig.l], the active power factor correction stage 6 comprises a single high-frequency switching electronic branch 18 connected to the output of the bidirectional synchronous rectifier bridge 16 via a single main inductor 8 and one saturable inductor 9 with a saturation current threshold. In a variant not shown, the active power factor correction stage 6 may comprise several main inductors 8 each having the same inductance value.In this case, the active power factor correction stage 6 comprises several high-frequency switching electronic branches 18, connected in parallel (and this, whether the input electrical supply network is single-phase, two-phase or three-phase). The number of high-frequency switching electronic branches 18 is then equal to the number of main inductances 8. The high-frequency switching electronic branch 18 ensures high-frequency switching of the input electrical current, which makes it possible to generate an input sinusoidal wave in phase with the voltage of the input electrical supply network, as well as high-frequency ripples intended to be filtered by the electromagnetic disturbance filtering stage 4.

[0028] The bidirectional synchronous rectifier bridge 16 comprises four switching members 23 and a microcontroller 25. Each switching member 23 comprises a low-frequency controllable electronic switch 26A, 26B, 26C, 26D. The bidirectional synchronous rectifier bridge 16 is provided with two input terminals 56A, 56B and two output terminals 58A, 58B. The microcontroller 25 can perform acquisitions from the terminals 56A, 56B, 58A, 58B and has four control terminals 60A-60D. A first input terminal 56A of the bidirectional synchronous rectifier bridge 16 is connected to the neutral output terminal 12A of the electromagnetic disturbance filtering stage 4. A second input terminal 56B of the bidirectional synchronous rectifier bridge 16 is connected to the phase output terminal 12B of the electromagnetic disturbance filtering stage 4.A first output terminal 58A of the bidirectional synchronous rectifier bridge 16 is connected to one end of the main inductor 8. A second output terminal 58B of the bidirectional synchronous rectifier bridge 16 is connected to one end of the saturable inductor 9 with saturation current threshold. Each control terminal 60A-60D of the microcontroller 25 is connected to the control electrode of a separate electronic switch 26A, 26B, 26C, 26D. A first electronic switch 26A is connected between the first input terminal 56A and the first output terminal 58A of the bidirectional synchronous rectifier bridge 16. A second electronic switch 56B is connected between the first input terminal 56A and the second output terminal 58B of the bidirectional synchronous rectifier bridge 16. A third electronic switch 26C is connected between the second input terminal 56B and the second output terminal 58B of the bidirectional synchronous rectifier bridge 16.A fourth electronic switch 26D is connected between the second input terminal 56B and the first output terminal 58A of the bidirectional synchronous rectifier bridge 16.

[0029] The high-frequency electronic switching branch 18 is connected between the two output terminals 7A, 7B of the electrical conversion system 2. The high-frequency electronic switching branch 18 comprises two high-frequency switching half-branches 18A, 18B connected in series at an intermediate terminal 22. Each high-frequency switching half-branch 18A, 18B comprises a switching member 24. In a variant not shown, each high-frequency switching half-branch 18A, 18B comprises a number N2 of switching members 24, N2 being an integer greater than or equal to two. In a further variant, only one high-frequency switching half-branch 18A, 18B comprises a number N3 of switching members, N3 being an integer greater than or equal to one. This variant corresponds, for example, to an active power factor correction stage 6 whose structure is of the multi-level type.The active power factor correction stage 6 also includes means (not shown in [Fig.l]). for controlling the switching of the switching members 23, 24 (at a different switching frequency depending on whether they are the switching members 23 of the bidirectional synchronous rectifier bridge 16 or the switching members 24 of the high-frequency switching electronic branch 18). The intermediate terminal 22 is connected to one end of the main inductance 8.

[0030] As known per se, each switching member 23, 24 is bidirectional in current and unidirectional in voltage. Each switching member 24 comprises a controllable electronic switch 27 and a diode 28 connected in antiparallel thus ensuring bidirectional current flow paths. Each switch 26A, 26B, 26C, 26D, 27 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 26A-26D, 27 are, for example, identical. The gate of each IGBT transistor 26A-26D, 27 is connected to the aforementioned control means to receive a corresponding control signal.Alternatively, the IGBT transistor 26A-26D, 27 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.

[0031] The intermediate terminal 22 is connected to one end of the main inductance 8 via a wire connection. In the variant (not shown in [Fig.l]) according to which the active power factor correction stage 6 comprises several high-frequency switching electronic branches 18 connected in parallel, each second intermediate terminal 22 is connected to a separate main inductance 8.

[0032] The means for controlling the switching members 24 are configured to control three control loops at the level of the high-frequency switching electronic branch 18 and the main inductance 8: a first control loop where the electric current is controlled via a current setpoint, a second control loop where the electric voltage is controlled via a voltage setpoint, and a third control loop for the current setpoint, which is controlled to be in phase with the voltage of the electrical supply network.

[0033] The saturable inductor 9 with saturation current threshold is connected between the second output terminal 58B of the microcontroller 25 and the negative voltage output terminal 7B of the electrical conversion system 2. The inductance value of the saturable inductor 9 when it is not saturated is chosen to be substantially equal to the inductance value of the main inductor 8. The saturable inductor 9 comprises for example a ferromagnetic ferrite material. Preferably, the saturable inductance 9 has a magnetization characteristic whose current threshold value is substantially equal to 1 A. This makes it possible to obtain rapid saturation of the inductance, while maintaining reasonable dimensions for the latter (which is advantageous because it makes it possible to reduce the size of the system).

[0034] During operation of the electrical conversion system 2, the saturable inductance 9 is caused to saturate suddenly if the value of the current flowing through it becomes greater than its current threshold value: the value of this inductance 9 thus saturated then becomes negligible in the circuit, which does not impact the nominal behavior of the system 2 (current regulated in a nominal manner) when the low-frequency controllable electronic switches 26A-26D are not switching.Conversely, when the current value becomes lower than the current threshold value of inductance 9 (in other words when the input electrical current and the input electrical voltage of system 2 are close to their zero values, and therefore inductance 9 is not saturated), saturable inductance 9 has its nominal value (substantially equal to the inductance value of main inductance 8) and plays the role of an additional filter on the neutral line of system 2.

[0035] The electrical conversion system 2 according to the invention makes it possible not to unbalance the electromagnetic disturbance filtering stage 4 when the input electrical current and the input electrical voltage are close to their zero values, as well as to reduce the disturbances on the neutral line of the system, and this without affecting the nominal behavior of the system when the low-frequency controllable electronic switches 26A-26D are not switching.

Claims

Claims

1. System (2) for converting a first electrical voltage (U1) into a second electrical voltage (U2) comprising an electromagnetic disturbance filtering stage (4) and an active power factor correction stage (6) connected to the output of the electromagnetic disturbance filtering stage (4), the conversion system (2) being provided with two output terminals (7A, 7B), the electromagnetic disturbance filtering stage (4) being suitable for being connected to an alternating electrical voltage source comprising a neutral conductive line (NI) and at least one phase conductive line (PI), and comprising a first output terminal (12A) connected to the neutral conductive line (NI) and at least one second output terminal (12B) connected to said at least one phase conductive line (PI),the active power factor correction stage (6) comprising a bidirectional synchronous rectifier bridge (16) and at least one high-frequency electronic switching branch (18) connected to the output of the bidirectional synchronous rectifier bridge (16) via at least one main inductor (8), said at least one high-frequency electronic switching branch (18) being further connected between the two output terminals (7A, 7B) of the conversion system (2), the number of high-frequency electronic switching branch(es) (18) being equal to the number of main inductors (8), the bidirectional synchronous rectifier bridge (16) comprising four first switching members (23) and a microcontroller (25), each first switching member (23) being provided with an electronic switch (26A, 26B, 26C, 26D) controllable at low frequency, the bidirectional synchronous rectifier bridge (16) comprising two terminals input (56A,56B) and two output terminals (58A, 58B), the microcontroller (25) being provided with four control terminals (60A-60D) and being configured to perform acquisitions from the two input terminals (56A, 56B) and the two output terminals (58A, 58B) of the bidirectional synchronous rectifier bridge (16), a first input terminal (56A) of the bidirectional synchronous rectifier bridge (16) being connected to the first output terminal (12A) of the electromagnetic disturbance filtering stage (4), a second input terminal (56B) of the bidirectional synchronous rectifier bridge (16) being connected to said at least one second output terminal (12B) of the per- filtering stage, electromagnetic disturbances (4), a first output terminal (58A) of the bidirectional synchronous rectifier bridge (16) being connected to said at least one main inductor (8), each control terminal (60A-60D) of the microcontroller (25) being connected to the control electrode of a separate electronic switch (26A, 26B, 26C, 26D), a first electronic switch (26A) being connected between the first input terminal (56A) and the first output terminal (58A) of the bidirectional synchronous rectifier bridge (16), a second electronic switch (26B) being connected between the first input terminal (56A) and the second output terminal (58B) of the bidirectional synchronous rectifier bridge (16), a third electronic switch (26C) being connected between the second input terminal (56B) and the second output terminal (58B) of the bidirectional synchronous rectifier bridge (16),a fourth electronic switch (26D) being connected between the second input terminal (56B) and the first output terminal (58A) of the bidirectional synchronous rectifier bridge (16), said at least one high-frequency electronic switching branch (18) comprising two high-frequency switching half-branches (18A, 18B) connected in series at an intermediate terminal (22), said intermediate terminal (22) being connected to the or one of the main inductance(s) (8), each high-frequency switching half-branch (18A, 18B) of said at least one high-frequency switching branch (18) comprising a second switching member (24) provided with a controllable electronic switch (26), characterized in that the electrical conversion system (2) further comprises a saturable inductance (9) with a saturation current threshold,said saturable inductance (9) being connected between the second output terminal (58B) of the bidirectional synchronous rectifier bridge (16) and one of the output terminals (7B) of the conversion system (2), the inductance value of said saturable inductance (9) when it is not saturated being substantially equal to the inductance value of said at least one main inductance (8).,

2. Electrical conversion system (2) according to claim 1, characterized in that said saturable inductance (9) comprises a ferromagnetic ferrite material.

3. Electrical conversion system (2) according to claim 1 or 2, characterized in that said saturable inductance (9) has a magnetization characteristic whose current threshold value is sens- possibly equal to 1 A.

4. Electrical conversion system (2) according to any one of claims 1 to 3, characterized in that each electronic switch (26A, 26B, 26C, 26D, 27) comprises a semiconductor electronic switching component, such as a transistor or a thyristor.

5. Electrical conversion system (2) according to any one of claims 1 to 4, characterized in that the conversion system is provided with a positive voltage output terminal (7A) and a negative voltage output terminal (7B), said saturable inductance (9) being connected between the second output terminal (58B) of the bidirectional synchronous rectifier bridge (16) and the negative voltage output terminal (7B) of the conversion system (2).

6. Electrical conversion system (2) according to any one of claims 1 to 5, characterized in that the electromagnetic disturbance filtering stage (4) comprises at least one common mode filtering member (Tl, C3, C4) and at least one differential mode filtering member (Cl, C2, Ll, L2).

7. Electric charger for an electric or hybrid vehicle intended to be connected to a terminal or an electric charging station connected to an alternating electric voltage source, for the electrical supply of said electric or hybrid vehicle, characterized in that it comprises a system (2) for converting a first electric voltage (U1) into a second electric voltage (U2) according to any one of claims 1 to 6.

8. Electric or hybrid vehicle, in particular an automobile, characterized in that it comprises an electric charger according to claim 7.

Images