WO2022207571A1

WO2022207571A1 - Title: isolated voltage converter

Info

Publication number: WO2022207571A1
Application number: PCT/EP2022/058161
Authority: WO
Inventors: Maxime MOREAU; Massourang DIALLO; Wendell DA CUNHA ALVES
Original assignee: Valeo Siemens Eautomotive France Sas
Priority date: 2021-03-29
Filing date: 2022-03-28
Publication date: 2022-10-06
Also published as: EP4315577A1; CN117581467A; FR3121298A1

Abstract

This isolated voltage converter (106) comprises: - first and second global input terminals (P, N) intended to receive a global input voltage (V_E) between them; and - a first and a second voltage conversion module (1081, 108₂), each with a primary circuit and a secondary circuit that are isolated and connected by a magnetic circuit, the primary circuits being connected in series between the global input terminals (P, N) so as each to receive only a portion of the global input voltage (V_E) as local input voltage (V_E1, V_E2). It furthermore comprises a device (118) for regulating the local input voltages (V_E1, V_E2) so as to keep them in a predefined ratio, for example to keep equal to one another.

Description

TITLE: ISOLATED VOLTAGE CONVERTER Technical field of the invention

The present invention relates to an isolated voltage converter and a motor vehicle comprising such an isolated voltage converter.

Technology background

The French patent application published under number FR 3064832 A1 describes an isolated voltage converter comprising: first and second global input terminals intended to receive a global input voltage; and a first and a second voltage conversion module each comprising an isolated primary circuit and a secondary circuit connected by a magnetic circuit, the primary circuit of the first voltage conversion module and the primary circuit of the second voltage conversion module being designed to be connected in series between the global input terminals to each receive, as local input voltage, only part of the global input voltage.

[0003] More specifically, in patent application FR 3064832 A1, the voltage converter is a DC-DC voltage converter, preceded by an AC-DC voltage converter intended to be connected to a single-phase AC electrical network or else three-phase. It is planned to leave the two modules in series when the electrical network is three-phase and to short-circuit one of the modules when the electrical network is single-phase.

[0004] This known voltage converter has the disadvantage that an imbalance can occur leading to the major part of the voltage conversion being carried out by only one of the modules, which can damage it if it is not sized to receive such electrical power.

[0005] It may thus be desirable to provide a voltage converter which makes it possible to overcome at least some of the aforementioned problems and constraints. Summary of the invention

[0006] An isolated voltage converter is therefore proposed comprising: first and second global input terminals intended to receive a global input voltage; and a first and a second voltage conversion module each comprising an isolated primary circuit and a secondary circuit connected by a magnetic circuit, the primary circuit of the first voltage conversion module and the primary circuit of the second voltage conversion module being designed to be connected in series between the global input terminals to each receive, as local input voltage, only part of the global input voltage; the isolated voltage converter being characterized in that it further comprises a device for regulating the local input voltages to maintain them in a predefined ratio, for example to maintain them equal to one another, when the circuits primaries are connected in series.

[0007] Thus, thanks to the invention, the regulation device prevents one module from taking precedence over the other.

[0008] Optionally, the primary circuits of the voltage conversion modules each comprise at least one semiconductor switch and the regulation device is designed to control the semiconductor switches so as to maintain the input voltages local in the predefined ratio. Thus, the regulation of local input voltages can easily be implemented.

[0009] Also optionally, the regulation device is designed to determine, from a difference between the local input voltages, a compensation and to control one of the voltage conversion modules from a setpoint voltage reduced by compensation and the other of the voltage conversion modules from the same setpoint increased by compensation. Thus, it is possible to regulate the local input voltages at the same time from a single compensation loop.

[0010] Also optionally, the regulation device is designed to determine the electrical setpoint from a difference between an output voltage of the isolated voltage converter and an output voltage setpoint. Thus, the output voltage is regulated at the same time as the local input voltages.

[0011] Also optionally, the electrical setpoint is a current setpoint and the compensation is a current compensation. In fact, the modules usually already include current regulation function blocks. For example, it is also possible to monitor this current to detect faults in the voltage converter. Thus, it is possible to reuse these function blocks to regulate local input voltages. Furthermore, the current regulation can make it possible to improve the dynamic performance of the voltage converter.

[0012] Also optionally, the primary circuit of each of the voltage conversion modules comprises two switches arranged as switching arms between two input terminals of the voltage conversion module considered and the regulation device is designed to control the two switching arm according to the same switching period and according to a duty cycle so as to maintain said local input voltages in the predefined ratio, and by shifting the commands of one of the switching arms by 45% to 55%, preferably 50%, of the switching period relative to the commands of the other switching arm. This shifting of the commands makes it possible to increase the frequency of the noise and to compensate for the disturbance currents.

[0013] Also optionally, the voltage converter further comprises a reconfiguration device designed to selectively connect the primary circuits in series, and connect the primary circuit of the first voltage conversion module between the two global input terminals so that its input voltage is equal to the input voltage.

[0014] Also optionally, the reconfiguration device is designed to selectively connect the primary circuits of the voltage conversion modules in parallel with each other between the global input terminals so that each local input voltage is equal to the global input voltage. Thus, the two modules are always used to realize the voltage conversion.

[0015] Also optionally, the reconfiguration device is designed to connect the primary circuit of the first voltage conversion module between the two global input terminals, to deactivate the second voltage conversion module. Indeed, the modules are generally designed to have their best performance at high power, for example between 50% and 100% of the nominal power. Thus, disabling the second module increases the chances that the first module will operate in its best performance range. On the contrary, if the modules were operated in parallel, they would each run the risk of operating outside their best performance range. [0016] Also optionally, the reconfiguration device is designed to place the primary circuits of the voltage conversion modules in series when the overall input voltage is within a first predefined voltage range and to connect the primary circuit of the first voltage conversion module between the two global input terminals when the global input voltage is in a second predefined range of voltages, lower than the first predefined range of voltages. Thus, the local input voltages are limited and do not take on excessively high values.

[0017] Also optionally, the first and second voltage conversion modules are DC-DC conversion modules.

[0018] Also optionally, the secondary circuits of the first and second voltage conversion modules are connected in parallel to each other at the output of the isolated voltage converter.

[0019] A motor vehicle is also proposed comprising a voltage converter according to the invention.

Brief description of figures

[0020] The invention will be better understood with the aid of the description which follows, given solely by way of example and made with reference to the appended drawings in which: [0021] FIG. 1 is an electrical diagram of a electrical system comprising a first example of a voltage converter according to the invention,

[0022] Figure 2 is an electrical diagram of one of two voltage conversion modules of the voltage converter of Figure 1,

[0023] FIG. 3 is an automatic regulation diagram implemented by a control device for the two voltage conversion modules,

Figure 4 is an electrical diagram of an electrical system comprising a second example of a voltage converter according to the invention,

[0025] FIG. 5 is an electrical diagram of an electrical system comprising a third example of a voltage converter according to the invention, and [0026] FIG. 6 groups control timing diagrams for controllable switches of voltage conversion modules . Detailed description of the invention

[0027] Referring to Figure 1, an electrical system 100 implementing the invention will now be described.

The electrical system 100 firstly comprises an electrical network 102 designed to deliver a network voltage VE. In the example described, the electrical network 102 is continuous, so that the network voltage VE is continuous.

The electrical system 100 further comprises a load 104 (such as a low voltage network) and an isolated voltage converter 106 intended to be connected to the electrical network 102 to convert the network voltage VE into an output voltage Vs supply of the load 104. In the example described, the voltage converter 106 is a DC-DC converter, so that the output voltage Vs is DC. Furthermore, the network voltage VE is for example a high voltage (i.e. for example a voltage greater than 60 V), while the supply voltage Vs is a low voltage (i.e. say for example a voltage lower than 60 V). For example, the network voltage VE is between 100 V and 900 V, while the supply voltage Vs is between 10 V and 50 V, generally equal to 14 V or else 48 V.

The network voltage VE received by the voltage converter 106 can take on very different values. This may come from the fact that the voltage converter 106 is intended to be successively connected to different electrical networks 102 and/or from the fact that the same electrical network 102 may see its network voltage VE vary over time, for example according to the mode operation of the electrical network 102. For example, when the electrical network 102 comprises one or more batteries intended to supply a voltage of 400 V, the network voltage VE can in fact vary between 170 V and 450 V depending on the load of the battery or batteries. batteries. When the electrical network 102 comprises one or more batteries intended to supply a voltage of 800 V, the network voltage VE can in fact vary between 470 V and 850 V depending on the charge of the battery or batteries. This is why the voltage converter 106 is preferably a direct voltage converter, designed to supply a substantially constant output voltage Vs over a whole range of possible network voltages VE.

[0031] The voltage converter 106 has first and second input terminals P, N between which the electrical network 102 is connected to deliver its network voltage VE between the terminals P, N. The voltage converter 106 further comprises first and second modules 108i, 1082 voltage conversion. In the example described, these modules 1081, 1082 are DC-DC converters. Preferably, modules 1081 and 1082 are substantially identical. Modules 1081, 1082 preferably include semiconductor switches.

The IO81, IO82 modules are for example connected to the load 104 in parallel with each other. Thus, they each supply the output voltage Vs.

Each module 1081, 1082 has first and second input terminals Pi, Ni, respectively P2, N2. In the example described, the input terminal Pi of the module 1081 is connected to the input terminal P of the voltage converter 106 and the input terminal Ni of the module 1081 is connected to the input terminal P2 of the module 1082.

The voltage converter 106 further comprises a device 110 for reconfiguring the connection of the modules 1081, 1082 to the electrical network 102. More specifically, the reconfiguration device 110 is designed to selectively: (i) connect the modules I O81 , IO82 in series between the input terminals P, N to each receive, as input voltage VEI , VE2, only part of the network voltage VE, and (ii) connect the 1081 module between the two input terminals P , N so that its input voltage VEI is equal to the network voltage VE. In the example described, in the latter case, the IO82 module is disabled, so that only the 1081 module performs the voltage conversion.

To switch from one connection configuration to another, the reconfiguration device 110 controls, for example, a switch 112 designed to connect the input terminal N selectively to the input terminal Ni of the module 1081 and to the input terminal N2 of the IO82 module. Thus, when the switch 112 connects the input terminal N to the input terminal Ni of the module 1081, the latter is connected between the two input terminals P, N so that its input voltage VEI is equal to the voltage EV network. The input terminal N2 of the 1082 module then presents a floating potential, so that the 1082 module is disconnected from the electrical network 102 and therefore inactive. When the switch 112 connects the input terminal N to the input terminal N2 of the IO82 module, the modules IO81, 1082 are then connected in series between the input terminals P, N to receive each, as an input voltage VEI ,

VE2, only part of the network voltage VE. More precisely, in the example described, the network voltage VE is equal to the sum of the input voltages VEI, VE2. The voltage converter 106 further comprises, still in the example described, a device 114 for measuring the network voltage VE and the reconfiguration device 110 is designed to control the switch 112 according to the network voltage VE measured . For example, the reconfigurator 110 is designed to determine in which of two predefined voltage intervals the input voltage VE lies. Preferably, these two predefined intervals do not overlap. In the example described, the first interval corresponds to the possible network voltages VE for a 400 V electrical network (i.e. for example 170 - 450 V) and the second interval corresponds to the possible network voltages VE for a 800 V electrical network (i.e. for example 470 - 850 V). For example, the measured input voltage VE can be compared with a predefined threshold making it possible to distinguish the two intervals. In the example described, this threshold could be between 450 V and 470 V.

The reconfiguration device 110 is then for example designed to control the switch 112 to connect the module 1081 between the two input terminals P, N when the network voltage VE belongs to the interval grouping together the smallest voltages ( the 170 - 450 V interval in the example described) and to connect the modules 1081, 1082 in series between the input terminals P, N when the network voltage VE belongs to the interval comprising the highest voltages (l range 470 - 850 V in the example described).

In the example described where the modules IO81, I O82 comprise semiconductor switches, the voltage converter 106 further comprises a device 118 controlled by these switches, in order for example to maintain the output voltage Vs equal to a setpoint Vs ^* .

Even if the IO81, IO82 modules are intended to be identical, there are always differences between the components, resulting for example from manufacturing tolerances. For this reason, when the 1081, 1082 modules are connected in series, there is a risk that one of the 1081, 1082 modules takes precedence over the other and does all the voltage conversion. To avoid this, it is proposed to try to keep the input voltages VE1, VE2 equal.

[0041] Thus, the voltage converter 106 further comprises a device for regulating the input voltages VEI, VE2 of the modules 1081, 1082, when the latter are connected in series, in order to seek to maintain these input voltages VEI , VE2 equal, in particular to within one uncertainty. For example, the converter voltage 106 comprises devices 120 for measuring the input voltages VEI, VE2 and the regulating device is designed to regulate the input voltages VEI, VE2 from their measurements.

Still for example, the regulation device is designed to control at least some of the semiconductor switches of the modules 108i, IO82, from the measured input voltages VEI, VE2. In the example described, the regulation device is implemented by the control device 118. An example of such a control device 118 will be described in more detail later, with reference to FIG. 3. FIG. 2, an example embodiment of the module 1082 will now be described. The 1081 module is similar and has substantially identical components, which will be designated below with the subscript "1" rather than the subscript "2" used for the components of the 1082 module.

The 1082 module firstly comprises an input capacitor CE2 connected between the terminals P2, N2 to smooth the input voltage VE2.

The module 1082 further comprises a first voltage converter 2022 designed to convert the input voltage VE2 into a continuous intermediate voltage VINÏ2.

The voltage converter 2022 comprises a switching arm comprising two semiconductor switches QA2, QB2 connected between the input terminals P2, N2 and to each other at a midpoint. Each of the semiconductor switches QA2, QB2 is for example a field effect transistor with a metal-oxide-semiconductor structure (from the English “Metal Oxide Semiconductor Field Effect T ransistor” or MOSFET) or else a bipolar transistor with gate isolated (from the English “Insulated Gate Bipolar Transistor” or IGBT).

The voltage converter 2022 further comprises an inductance L2 and a capacitor CINÏ2 connected one after the other between the midpoint of the switching arm QA2, QB2 and the input terminal N2. Intermediate voltage VINT2 is thus the voltage across capacitor CINT2. [0048] The module 1082 further comprises a second voltage converter

2042 designed to convert the intermediate voltage VINT2 into the output voltage Vs.

The voltage converter 2042 comprises in particular a galvanic isolation barrier 2062 comprising a magnetic circuit 2082 which, in the example described couples one or more primary windings 21 02 and one or more secondary windings 21 22 together.

In the example described, the voltage converter 2042 is a so-called "flyward" converter described for example in detail in the French patent application published under the number FR 3056038 A1. In a converter of this type, there are two semiconductor switches QC2, QD2 connected to each other by a middle capacitor CF2, the assembly being connected to the terminals of the intermediate capacitor CINT2 to receive the intermediate voltage VINT2 . Each of the semiconductor switches QC2, QD2 comprises for example a MOSFET or else an IGBT.

[0051] The voltage conversion module 1082 thus has a primary circuit 2142 and a secondary circuit 2162 isolated, connected by the magnetic circuit 2082. The primary circuit 2142 comprises in particular the terminals P2, N2 to receive the local input voltage VE2. In the example described, the primary circuit 2142 includes the voltage converter 2022, the components of the voltage converter 2042 connected between the voltage converter 2022 and the primary winding(s) 2102, and this or these primary windings 2102. For its part , the secondary circuit 2162 includes the components of the voltage converter 2042 connected between the secondary winding(s) and output terminals 2182 of the voltage conversion module 1082.

[0052] Referring to Figure 3, an example of control device 118 will now be described in more detail.

The control device 118 firstly comprises a comparator 302 designed to determine a difference AVs between the measured output voltage Vs and an output voltage setpoint Vs ^* .

The control device 118 further comprises a regulator 304 designed to determine a so-called initial electrical set point from the AVs deviation. In the example described, the initial electrical setpoint is a current setpoint I ^* .

The control device 118 further comprises a comparator 306 designed to determine a difference AVE between the input voltages VEI, VE2.

[0056] The controller 118 further includes a regulator 308 designed to determine a compensation from the deviation AVE. In the example described, the ICOMP compensation is a current compensation. The control device 118 further comprises, for the control of one of the modules (the module 1081 in the example described), a subtractor 310 designed to reduce the setpoint I ^* of the ICOMP compensation to provide a setpoint so-called final h ^* for this 108i module. In the example described, this final setpoint h ^* is a current setpoint for the current flowing in the inductance of the module considered (inductance Li in the example described).

The control device 118 also comprises, for the control of the other of the modules (the module 1082 in the example described), an adder 312 designed to increase the initial setpoint I ^* of the ICOMP compensation to provide a so-called final setpoint 1*2 for this module 1082. In the example described, this final setpoint I2 ^* is a current setpoint for the current flowing in the inductance of the module considered (inductance L2 in the example described).

For the control of the module 1081, the control device 118 further comprises a comparator 314 designed to determine a difference DH between the measured current h and the final setpoint 1*1 and a device 316 designed to determine commands for the switches QA1 , QB1 of the 1081 module from this deviation DH .

Similarly, for the control of the module 1082, the control device 118 further comprises a comparator 318 designed to determine a difference DI2 between the measured current I2 and the final setpoint 1*2 and a device 320 designed to determine commands for the QA2, QB2 switches of the 1082 module from this DI2 deviation.

[0061] The commands are for example in the form of signals in pulse width modulation (from English "Pulse Width Modulation" or PWM) having a duty cycle determined according to the difference DH or DI2, according to the device 316 or 320 considered.

The devices 316, 320 can also be designed to determine commands for the switches QC1, QD1, respectively QC2, QD2. These commands are for example also PWM signals, but whose duty cycle is fixed (in particular, independent of the DH or DI2 deviation).

Each of the regulators 304, 308 is for example one of: a PID regulator, a PI regulator and a non-linear regulator.

[0064] With reference to FIG. 4, another example 402 of voltage converter according to the invention will now be described. This voltage converter is similar to that of Figure 1, except that it does not include the switch 112.

In this embodiment, the terminal N2 of the module 1082 is connected to the terminal N. In addition, the reconfiguration device 110 is then for example designed to control, for example independently of the commands of the control device 118, the switching arms QA2, QB2 to short-circuit the terminals P2, N2 when the network voltage VE belongs to the interval comprising the smallest voltages (the interval 170 - 450 V in the example described) and to leave the device de commanded 118 command switches QA2, QB2 so that the IO82 module performs the desired voltage conversion, in series with the IO81 module, when the network voltage VE belongs to the interval comprising the highest voltages (the interval 470 - 850 V in the example described).

With reference to FIG. 5, another example 502 of voltage converter according to the invention will now be described.

[0068] This embodiment is similar to that of Figure 1, except that the switch 112 is replaced by a switch 504 designed to selectively connect the two modules 1081, 1082 in series and in parallel to the electrical network 102 In the parallel configuration, each input voltage VEI, VE2 is thus equal to the network voltage VE.

In the example described, terminal Pi of module 1081 is connected to terminal P and terminal N2 of module 1082 is connected to terminal N. Thus, to switch from one configuration to another, the switch 504 is designed to change Ni , P2 terminal connection. More specifically, in the example described, for the parallel configuration, the switch 504 is designed to connect the P2 terminal to the P terminal and the Ni terminal to the N terminal. For the series configuration, the switch 504 is designed to connect together terminals Ni and P2.

The reconfiguration device 110 is then for example designed to control the switch 504 to connect the two modules 1081, 1082 in parallel between the two input terminals P, N when the network voltage VE belongs to the interval grouping the voltages the smallest (the 170 - 450 V interval in the example described) and to connect the modules 1081, 1082 in series between the input terminals P, N when the network voltage VE belongs to the interval grouping together the voltages higher (the range 470 - 850 V in the example described). [0071] Referring to Figure 6, timing diagrams illustrating examples of commands QAi switches, QA2, QC1, QC2 will now be described. On these timing diagrams, the abscissa represents the time in milliseconds and the ordinate the control voltage in volts.

The commands of the switches QB1, QB2, QD1, QD2 are not represented because they are deduced from the commands of the switches QA1, QA2, QC1, QC2: the switches QB1, QB2 are respectively controlled in opposition to the switches QA1, QA2 ( preferably with a dead time) and the switches QD1, QD2 are respectively controlled in opposition to the switches QC1, QC2 (preferably with a dead time).

As can be seen in the first timing diagram, command C_QA2 of switch QA2 alternates between two opening and closing values respectively according to a period TB equal to the inverse of a switching frequency FB. In the example described, this switching frequency F B is fixed and predefined and the control device 118 is designed to determine a duty cycle of the command C_QA2 from the local input voltages VEI, VE2, to maintain the latter in the predefined ratio. As illustrated in Figure 3, in the example described, the duty cycle of the command C_QA2 is determined by the device 320 from the deviation DI2.

Similarly, as can be seen in the second timing diagram, command C_QAi of switch QA1 alternates between two opening and closing values respectively according to period TB. In the example described, the control device 118 is designed to determine a duty cycle of the command C_QAi from the local input voltages VEI, VE2, to maintain the latter in the predefined ratio. As illustrated in Figure 3, in the example described, the duty cycle of the command C_QAi is determined by the device 316 from the deviation DI1.

In addition, preferably, the commands of one of the switching arms are shifted by 45% to 55%, preferably 50%, of the switching period TB with respect to the commands of the other switching arm. This is illustrated in FIG. 6 by the double arrow TB/2.

As can be seen in the third and fourth timing diagrams, the commands C_QCi, C_QC2 of the switches QC1, QC2 alternate between two opening and closing values respectively according to a switching period TF. In the example described, this switching period TF is fixed and the commands C_QCi , C_QC2 have equal and fixed duty cycles.

In addition, preferably, the commands of one of the pairs of switches (the pair QC2, QD2 in the example described) is shifted by 20% to 30%, preferably 25%, of the switching period TF with respect to the commands of the other pair of switches (the pair QC1, QD1 in the example described). This is illustrated in FIG. 6 by the double arrow TF/4.

It clearly appears that a voltage converter such as those described above makes it possible to maintain the functioning of the modules in balance.

It will also be noted that the invention is not limited to the embodiments described above. It will indeed appear to those skilled in the art that various modifications can be made to the embodiments described above, in the light of the teaching which has just been disclosed to them.

For example, the shift of approximately 25% is valid in the case where the second voltage converter 204i, 2042 is of the flyward type. For other types of converters, the offset could be different. For example, it could be between 45% and 55%, preferably 50%, for a phase shift converter or for a resonant LLC converter.

In the detailed presentation of the invention which is made previously, the terms used must not be interpreted as limiting the invention to the embodiments set out in the present description, but must be interpreted to include therein all the equivalents of which forecasting is within the reach of those skilled in the art by applying their general knowledge to the implementation of the teaching which has just been disclosed to them.

Claims

[1] Isolated voltage converter (106; 402; 502) comprising: first and second global input terminals (P, N) intended to receive between them a global input voltage (VE); and - a first and a second voltage conversion module (108i, 1082) each comprising a primary circuit (2142) and a secondary circuit (2162) isolated connected by a magnetic circuit (2O82), the primary circuit of the first conversion module voltage converter (1081) and the primary circuit (2142) of the second voltage conversion module (1082) being adapted to be connected in series between the global input terminals (P, N) to receive each, as an input voltage local (VEI, VE2), only part of the global input voltage (VE); the isolated voltage converter being characterized in that it further comprises a device (118) for regulating the local input voltages (VEI , VE2) to maintain them in a predefined ratio, for example to maintain them equal to one the other, when the primary circuits (2142) are connected in series.

[2] Isolated voltage converter (106; 402; 502) according to claim 1, wherein the primary circuits (2142) of the voltage conversion modules (1081, I O82) each comprise at least one semiconductor switch ( QA2, QB2) and wherein the regulating device (118) is adapted to control the semiconductor switches (QA2, QB2) so as to maintain the local input voltages (VEI , VE2) in the predefined ratio.

[3] Isolated voltage converter (106; 402; 502) according to claim 2, in which the regulation device (118) is designed to determine, from a deviation (AVE) between the local input voltages ( VEI, VE2), a compensation (ICOMP) and to control one of the voltage conversion modules (1081, 1082) from an electrical setpoint (I ^* ) reduced by the compensation (ICOMP) and the other of the modules voltage conversion (IO81, 1082) from the same setpoint (I ^* ) plus compensation (ICOMP).

[4] Isolated voltage converter (106; 402; 502) according to claim 3, in which the regulating device (118) is designed to determine the setpoint (I ^* ) from a difference (D /s) between an output voltage (Vs) of the isolated voltage converter (106) and an output voltage setpoint (Vs ^* ).

[5] Isolated voltage converter (106; 402; 502) according to claim 3 or 4, wherein the electrical setpoint ( ) is a current setpoint and wherein the compensation (ICOMP) is a current compensation.

[6] Isolated voltage converter (106; 402; 502) according to any one of claims 2 to 5, wherein the primary circuit (2142) of each of the voltage conversion modules (1081, IO82) comprises two switches ( QA2, QB2) arranged as a switching arm between two input terminals (Pi, Ni, P2, N2) of the voltage conversion module (1081, 1082) considered and in which the regulation device (118) is designed to control the two switching arms according to the same switching period (TB) and according to a duty cycle so as to maintain said local input voltages (VEI , VE2) in the predefined ratio, and by shifting the commands of one of the switching arms from 45% to 55%, preferably 50%, of the switching period (TB) relative to the commands of the other switching arm.

[7] Isolated voltage converter (106; 402; 502) according to any one of claims 1 to 6, further comprising a reconfiguration device (110) adapted to selectively connect the primary circuits (2142) in series, and connect the primary circuit of the first voltage conversion module ( 1081 ) between the two global input terminals (P, N) so that its input voltage (VEI) is equal to the input voltage (VE).

[8] Isolated voltage converter (502) according to claim 7, wherein the reconfiguration device (110) is adapted to selectively connect the primary circuits (2142) of the voltage conversion modules (1081, 1082) in parallel each other between the global input terminals (P, N) so that each local input voltage (VEI , VE2) is equal to the global input voltage (VE).

[9] Isolated voltage converter (106; 402) according to claim 7, wherein the reconfiguration device (110) is designed to connect the primary circuit of the first voltage conversion module (1081) between the two terminals of global inputs (P, N), to deactivate the second voltage conversion module (1082).

[10] Isolated voltage converter (106; 402; 502) according to any one of claims 7 to 9, in which the reconfiguration device (110) is adapted to place the primary circuits (2142) of the voltage conversion modules (108i,

1082) in series when the global input voltage (VE) is within a first predefined range of voltages and to connect the primary circuit of the first voltage conversion module (1081) between the two global input terminals (P, N) when the overall input voltage (VE) is within a second predefined range of voltages, lower than the first predefined range of voltages.

[11] Isolated voltage converter (106; 402; 502) according to any one of claims 1 to 10, wherein the first and second voltage conversion modules (IO81, IO82) are DC-DC conversion modules.

[12] Isolated voltage converter (106; 402; 502) according to any one of claims 1 to 11, in which the secondary circuits (2162) of the first and second voltage conversion modules (IO81, I O82) are connected in parallel with each other at the output of the isolated voltage converter.

[13] Motor vehicle comprising a voltage converter (106; 402; 502) according to any one of claims 1 to 12.