MODULAR ELECTRIC CONVERSION SYSTEM AND MOBILITY MACHINE COMPRISING SUCH A SYSTEM

Abstract

The modular electrical conversion system (114) comprises: - several electrical conversion modules (M1, M2, M3); and - an output bus (126) to which the outputs (1221, 1222, 1223) are connected; the control device (1181) of one of the modules, called master module (M1), the other module(s) being called slave modules (M2, M3), being designed to control the voltage (UB) of the output bus (126) to a setpoint (UB*). The master module (M1) is designed to apply the control (C1) of the voltage control without control of the output current (IB1). The system (114) further comprises a setpoint calculation system (403) for each slave module (M2, M3). Each slave module (M2, M3) is designed to control its output current (IB2, IB3) to the calculated setpoint (IB2*, IB3*). Figure for summary: Fig. 2

Description

Title of the invention: CONVERSION SYSTEM MODULAR ELECTRIC SYSTEM AND MOBILITY MACHINE COMPRISING SUCH A SYSTEM Technical field of the invention

[0001] The present invention relates to a modular electric conversion system and a mobility device comprising such a system.

[0002] A mobility device is, for example, a motorized land vehicle, a train, an aircraft or a drone. A motorized land vehicle is, for example, a motor vehicle, a motorcycle, a motorized bicycle or a motorized wheelchair. Technological background

[0003] The article entitled "Master-Slave Current-Sharing Control of a Parallel DC-DC Converter System Over an RF Communication Interface", by Sudip et al., describes a modular electrical conversion system comprising: - several electrical conversion modules each comprising: • a switching circuit with an input for receiving an input voltage and an output for presenting an output voltage and providing an output current, and • a switching circuit control device; - an output bus to which the outputs are connected, such that the output voltages are all equal to an output bus voltage;

[0004] in which the control device of one of the modules, called master module, the other module(s) being called slave modules, is designed to implement a closed-loop control designed to provide a command to modify the output current, in order to control the voltage of the output bus to a setpoint, from a measurement of the voltage of the output bus.

[0005] In this article, the control device of the master module is further designed to implement a second closed-loop control to control the current supplied by the master module to the current modification command.

[0006] Furthermore, this current modification command is provided to each slave module, in which the control device is designed to implement a closed-loop control in order to control the current provided by this slave module to the current modification command received.

[0007] The structure proposed in this article has the disadvantage that the control device of the master module comprises two loops closed one after the other: a voltage loop, followed by a current loop. However, because of this, the loop of The current loop must be much more dynamic than the voltage loop, i.e., have a much higher bandwidth. Thus, with a given technology for implementing the modules (e.g., software implementation), the maximum bandwidth allowed by that technology will be implemented in the current loop. The voltage loop will then have a much lower bandwidth than that technology allows.

[0008] It may thus be desirable to provide a modular electrical conversion system which makes it possible to overcome at least some of the aforementioned problems and constraints. Summary of the invention

[0009] A modular electrical conversion system is therefore proposed comprising: - several electrical conversion modules each comprising: • a switching circuit with an input for receiving an input voltage and an output for presenting an output voltage and providing an output current, and • a switching circuit control device; - an output bus to which the outputs are connected, such that the output voltages are all equal to an output bus voltage;

[0010] in which the control device of one of the modules, called master module (Ml), the other module(s) being called slave modules, is designed to implement a closed-loop control, called master control, designed to provide a command to modify the output current, in order to control the voltage of the output bus to a setpoint, from a measurement of the voltage of the output bus;

[0011] characterized in that: - the master module control device is designed to apply the command to the switching circuit without controlling the output current to this command; - it further comprises a setpoint calculation system designed to calculate, for each slave module, a setpoint for its output current from a measurement of the output current of the master module or from a measurement of a total current supplied to the output bus by all the modules, so that the sum of the setpoints is less than the total current; and - the control device of each slave module is designed to implement a closed-loop control, called slave control, designed to provide a command to modify the output current, in order to control the output current to the calculated setpoint, from a measurement of the output current, the control device being designed to apply the control to the switching circuit.

[0012] Thus, thanks to the invention, the control device of the master module only implements a single loop, that of voltage. The absence of regulation of the output current makes it possible to use, for voltage regulation, the maximum bandwidth permitted by the technology used to implement the modules.

[0013] The invention may further comprise one or more of the following optional features, in any technically possible combination.

[0014] Optionally, the master servo is designed to have a bandwidth and the slave servo is designed to have a bandwidth at least ten times smaller than that of the master servo, as the total current increases.

[0015] Also optionally, the slave servo is designed so that its bandwidth is substantially equal to that of the master servo, when the total current decreases.

[0016] Also optionally, the slave servo is designed to modify its bandwidth according to the total current with a hysteresis cycle.

[0017] Also optionally, the output current setpoint of each slave module is taken equal to the total current divided by the number of modules.

[0018] Also optionally, the output current setpoint of each slave module is calculated as the product of a contribution by the total current, the sum of the contributions being less than one, or as the product of a contribution by the output current of the master module.

[0019] Also optionally, contributions are predefined in each slave module.

[0020] Also optionally, each slave module is designed to receive its contribution from an external device, for example the master module or a device separate from the modules.

[0021] Also optionally, each module is designed to selectively be the master module and the or one of the slave modules.

[0022] Also optionally, the modules are DC-DC or AC-DC or DC-AC converters.

[0023] Also optionally, the system further comprises an input bus to which the inputs are connected, such that the input voltages are all equal to an input bus voltage.

[0024] A mobility device comprising a modular electric conversion system according to the invention is also proposed.

[0025] Optionally, the mobility device comprises: - a DC voltage source connected to the input bus; and

[0026]

[0027]

[0028]

[0029]

[0030] - at least one device connected to the output bus. Brief description of the figures The invention will be better understood with the aid of the following description, given solely by way of example and made with reference to the appended drawings in which: - [Fig.l] is a functional view of a mobility device in which the invention can be implemented, - [Fig.2] is a functional view of a modular electrical conversion system according to the invention, - [Fig.3] is a functional view of a control device of a module of the modular electrical conversion system of [Fig.2], when in a master mode, - [Fig.4] is a functional view of a control device of a module of the modular electrical conversion system of [Fig.2], when in a slave mode, and - [Fig.5] is a functional view of a computing device capable of implementing a module of the modular electrical conversion system of [Fig.2], Detailed description of the invention With reference to [Fig.l], a mobility device 100, in which the invention can be implemented, will now be described. The mobility device 100 includes a movement system 102, such as one or more drive wheels, configured to put the mobility device 100 into motion. To drive the movement system 102, the mobility device 100 further comprises an electric drive device 104 and a direct voltage source 106, such as a battery, designed to electrically power the electric drive device 104. The direct voltage source 106 is in particular a high voltage source, i.e. for example greater than 100 V. The electric drive device 104 comprises an electric machine 108, in particular polyphase, for example three-phase, connected to the movement system 102 to drive the latter. The electric drive device 104 further comprises an AC-DC electric voltage converter 110 connected between the DC voltage source 106 and the electric machine 108. The electric voltage converter 110 is configured to transfer electric power between the DC voltage source 106 and the electric machine 108. For example, the AC-DC converter 110 is configured to operate as an inverter to transfer electric power from the DC voltage source 106 to the electric machine 108 operating as an electric motor. The converter al DC-DC 110 may also be configured to operate as a rectifier to transfer electrical power from the electrical machine 108 operating as an electrical generator to the DC voltage source 106, for example to recharge the latter.

[0031] Furthermore, the mobility device 100 comprises one or more pieces of equipment 112 and a modular electrical conversion system 114, DC-DC in the illustrated example, designed to convert the high voltage of the DC voltage source 106 into a low supply voltage of the piece of equipment 112. A low voltage is for example a voltage lower than 100 V, preferably lower than 48 V.

[0032] With reference to [Fig.2], an exemplary embodiment according to the invention of the modular electrical conversion system 114 will now be described.

[0033] The modular electrical conversion system 114 comprises several electrical conversion modules M1, M2, M3. For example, as in the example described, the modules M1, M2, M3 are DC-DC converters.

[0034] Each module M1, M2, M3 comprises a switching circuit 116b 1162, 1163 and a control device 118b 1182, 1183 of the switching circuit 116b 1162, 1163.

[0035] Each switching circuit 116b 1162, 1163, thus comprises an input 120b 1202, 1203 for receiving an input voltage, and an output 122i, 1222, 1223 for presenting an output voltage and providing an output current IB1, IB2, IB3.

[0036] For example, the modules M1, M2, M3 are electrically powered by the same source (for example, the DC voltage source 106 in the illustrated example). In this case, the modular electrical conversion system 114 comprises, for example, an input bus 124 to which the inputs 120i, 1202, 1203 are connected, so that the input voltages are all equal to a voltage UA of the input bus 124 (for example, the voltage of the DC voltage source 106 in the illustrated example).

[0037] The modular electrical conversion system 114 further comprises an output bus 126 to which the outputs 122b 1222, 1223 are connected, so that the output voltages are all equal to a voltage UB of the output bus 126. Furthermore, the equipment(s) 112 are connected to the output bus 126.

[0038] Each switching circuit 116b 1162, 1163 comprises one or more switches (not shown) controllable by the associated control device 118b 1182, 1183. Each switch is preferably a controllable semiconductor switch, such as for example a metal-oxide gate field effect transistor (also designated by the acronym MOSFET) or a silicon metal-oxide gate field effect transistor (also designated by the acronym Si MOSFET) or a silicon carbide metal-oxide gate field effect transistor (also designated by the acronym Si Carbide Metal Oxide Semiconductor Field Effect Transistor (also referred to by the acronym SiC MOSFET) or an Insulated Gate Bipolar Transistor (also referred to by the acronym IGBT) or a Gallium Nitride Field Effect Transistor (also referred to by the acronym GaN FET).

[0039] For example, the switching circuits 116b 1162, 1163 are series choppers (called in English "buck converters") using a controllable switch. Still for example, the switching circuits 116i, 1162, 1163 can comprise at least one switching bridge with at least one controllable switch, for example with four controllable switches (the switching bridge is then said to be active). For example, the switching circuits 116i, 1162, 1163 comprise two active switching bridges and an isolation transformer connecting them to each other. Such a configuration is called in English "dual active bridge".

[0040] The modular electrical conversion system 114 further comprises a device 128 for measuring the voltage UB of the output bus 126, providing a measurement UB', and a device 130 for measuring a total current IB supplied by the modules M1, M2, M3 to the output bus 126, providing a measurement IB'. The modular electrical conversion system 114 further comprises, for each module M1, M2, M3, a device 132i, 1322, 1323 for measuring the output current IB1, IB2, IB3 by the module M1, M2, M3 considered, providing a measurement IB1', IB2', IB3'.

[0041] Each control device 1181, 1182, 1183 is designed to selectively operate in two modes: a master mode (its module M1, M2, M3 is then called master module) and a slave mode (its module M1, M2, M3 is then called slave module). When one of the modules M1, M2, M3 is the master module, the other module(s) are slave modules. In the remainder of the description, when it is necessary to specify, it will be assumed that the module M1 is the master module and that the modules M2, M3 are the slave modules.

[0042] Each control device 1181, 1182, 1183 is designed, when in the master mode, to implement a closed-loop control, called master control, designed to provide a command C1, C2, C3 for modifying the output current IB1, IB2, IB3, in order to control the voltage UB to a setpoint UB*, from the measurement UB'. More precisely, the command C1, C2, C3 is called a command for modifying the output current IB1, IB2, IB3 in the sense that it is designed to cause a modification of the output current IB1, IB2, IB3. The control device 118i, 1182, 1183 is then designed to apply the command Cl, C2, C3 to the switching circuit 116i, 1162, 1163 in open loop, that is to say that the command Cl, C2, C3 is applied without control of the output current to this command Cl, C2, C3, and therefore in particular without using measurement of the output current IB1, IB2, IB3.

[0043] With reference to [Fig. 3], an exemplary embodiment of the master servo, designated by the reference 302, will now be described. In this figure, the elements are indicated with an index n, equal to 1, 2 or 3 to respectively signify the module M1, M2 or M3.

[0044] The master control 302 firstly comprises a comparator 304 designed to compare the setpoint UB* with the measurement UB', in order to provide a voltage error.

[0045] The master servo 302 further comprises a corrector 306 designed to provide a control signal S1, S2, S3 from the voltage error. For example, the corrector 306 is a proportional-integral corrector, as in the example illustrated. As is known per se, it is then in particular defined by a proportional coefficient Kp and an integral coefficient Ki, these coefficients Ki, Kp preferably being the same for all the modules M1, M2, M3. Alternatively, a proportional-integral-derivative corrector could be used.

[0046] To apply the command C1, C2, C3, the master servo 302 further comprises a converter 308 designed to convert the control signal S1, S2, SC3 into the command C1, C2, C3 which is for example in the form of switching signals for the switch(es) of the switching circuit 116i, 1162, 1163, for example in the form of one or more duty cycles for the switch(es).

[0047] Generally, the master servo 302 has a certain bandwidth BM, which is, as is known per se, the frequency band (from zero to a certain so-called cut-off frequency) on which the closed-loop servo system has a gain greater than -3 dB. In the case where the corrector 306 is a proportional-integral corrector, the bandwidth is equal to Ki / Kp.

[0048] Furthermore, each module M1, M2, M3 is further designed, when in the slave mode, to control its output current IB1, IB2, IB3 to a setpoint IB1*, IB2*, IB3*. For this, the control device 1181, 1182, 1183 of each module M1, M2, M3 is for example designed to implement a closed-loop control, called slave control, designed to provide a command C1, C2, C3 for modifying the output current IB1, IB2, IB3, in order to control the output current IB1, IB2, IB3 to the setpoint IB1*, IB2*, IB3* calculated from the measurement IB1', IB2', IB3'. The control device 118i, 1182, 1183 is then designed to apply the command C1, C2, C3 to the switching circuit 116i, 1162, 1163.

[0049] The modular electrical conversion system 114 thus comprises a setpoint calculation system designed, for each slave module M1, M2, M3, to calculate its setpoint IB1*, IB2*, IB3* from the measurement IB' of the total current IB. The calculation of the setpoints IB1*, IB2*, IB3* is provided so that the sum of the setpoints IB1*, IB2*, IB3* of the slave modules M1, M2, M3 is less than the total current IB. Thus, there remains a current margin for the master module Ml, M2, M3. For example, the setpoint IB1*, IB2*, IB3* of each slave module Ml, M2, M3 is taken equal to the total current IB (or its measurement IB') divided by the number of modules, i.e. in the example illustrated: IBn* = IB / 3. Of course, in the case where there is only one slave module, the sum of the setpoints is equal to the setpoint of the single slave module.

[0050] The setpoint calculation system can be distributed over the modules Ml, M2, M3. In this case, each slave module M1, M2, M3 is designed to calculate its setpoint IB1*, IB2*, IB3*. For example, the setpoint IB1*, IB2*, IB3* is calculated as the product of a contribution K1, K2, K3 associated with the module M1, M2, M3 considered, by the measurement IB' of the total current IB: IBn* = Kn x IB'. The contribution K1, K2, K3 can either be predefined and recorded in the module M1, M2, M3, or received by the latter from another device which can thus redefine the contributions K1, K2, K3 over time. This other device can be the master module M1, M2, M3 or a device external to the modules M1, M2, M3, for example a supervisor (not shown) of the mobility device 100 or a supervisor (not shown) of the DC voltage source 106.In order for the sum of the setpoints IB1*, IB2*, IB3 * of the output currents IB1, IB2, IB3 to be less than the total current IB, the sum of the contributions Kl, K2, K3 of the slave modules Ml, M2, M3 is preferably less than one. With the module Ml in master mode, this means that: K2 + K3 < 1. Of course, in the case where there is only one slave module, the sum of the contributions is equal to the contribution of the single slave module. To ensure that the sum of the contributions Kl, K2, K3 of the slave modules Ml, M2, M3 is always less than one, whatever the master module Ml, M2, M3, it is for example possible to choose the coefficients Kl, K2, K3 so that their sum is equal to one, or even less than one: Kl + K2 + K3 < 1.

[0051] Alternatively, the setpoint calculation system may be provided outside the modules M1, M2, M3 (for example, in one of the supervisors indicated above). The setpoint calculation system is then designed to respectively transmit each setpoint IB1*, IB2*, IB3* to the slave module M1, M2, M3 concerned, either directly in the form of a current setpoint, or in the form of a power setpoint that the slave module M1, M2, M3 will be designed to convert into a current setpoint, for example from the measurement UB' of the voltage UB of the output bus 126.

[0052] With reference to [Fig.4], an example of embodiment of the slave control, designated by the reference 402, will now be described, in the case where each module M1, M2, M3 is designed to calculate its setpoint IB1*, IB2*, IB3* of output current IB1, IB2, IB3 from its contribution K1, K2, K3. The slave module M1, M2, M3 thus comprises a multiplier 403 designed to multiply the measurement IB' of the current total IB by the contribution Kl, K2, K3, in order to provide the instruction IB1*, IB2*, IB3*. In this figure, the elements are indicated with an index n, worth 1, 2 or 3 to respectively signify the module Ml, M2 or M3.

[0053] The slave control 402 firstly comprises a comparator 404 designed to compare the setpoint IB1*, IB2*, IB3* with the measurement IB1', IB2', IB3', in order to provide a current error.

[0054] The slave control 402 further comprises a corrector 406 designed to provide a control signal S1, S2, S3 from the current error. For example, the corrector 406 is a proportional-integral corrector, as in the example illustrated. As is known per se, it is then in particular defined by a proportional coefficient Kp and an integral coefficient Ki, these coefficients Ki, Kp preferably being the same for all the modules M1, M2, M3. Alternatively, a proportional-integral-derivative corrector could be used.

[0055] The control device 118i, 1182, 1183 further comprises a converter 408 designed to convert the control signal SI, S2, S3 into the control Cl, C2, C3 which is for example in the form of switching signals for the switch(es) of the switching circuit 116i, 1162, 1163, for example into one or more duty cycles for the switch(es).

[0056] Generally, the slave control 402 has a certain bandwidth BE. In the case where the corrector 406 is a proportional-integral corrector, the bandwidth BE is equal to Ki / Kp.

[0057] Preferably, the slave servo 402 is designed so that its bandwidth BE is at least ten times smaller than the bandwidth BM of the master servo 302, when the total current IB increases. On the other hand, the slave servo 402 is preferably designed so that its bandwidth BE is between 0.5 and 1.5 times the bandwidth BM of the master servo 302, when the total current IB decreases.

[0058] Thus, each control device 1181, 1182, 1183 is designed, when in the slave mode, to modify the bandwidth BE according to the evolution of the total current IB. For this, each control device 118i, 1182, 1183 is for example designed to modify the coefficient Kp and / or the coefficient Ki, for example by increasing the coefficient Kp and / or decreasing the coefficient Ki to decrease the bandwidth BE and by decreasing the coefficient Kp and / or increasing the coefficient Ki to increase the bandwidth BE. Preferably, the coefficient Ki is modified, and not the coefficient Kp, because a modification of the coefficient Ki makes it possible to directly discharge the accumulation of the integrator.

[0059] Preferably, to avoid successive modifications of the bandwidth BE too close together when the total current IB fluctuates, each control device 118i, 1182, 1183 is designed to change the bandwidth BE depending on the total current IB with a hysteresis loop.

[0060] To determine whether the total current IB increases or decreases, each control device 118i, 1182, 1183 further comprises, for example, a block 410 designed to divide the measurement IB1', IB2', IB3' by the measurement IB' to provide an effective contribution Kl', K2', K3'. The control device 118i, 1182, 1183 is then designed to compare the effective contribution Kl', K2', K3' to the contribution Kl, K2, K3, for example with a hysteresis cycle.

[0061] Indeed, in the case where a device 112 decreases its current draw from the output bus 126, the bus voltage UB will tend to increase. The master M1 will decrease in response its output current IB1, so that the total current IB will decrease under the effect of the master module ML. Each slave module M2, M3 will decrease in response its output current IB2, IB3 but much more slowly than the total current IB, because the bandwidth BE of the slave modules M2, M3 is much smaller than the bandwidth BM of the master module. Thus, the output currents IB2, IB3 will decrease more slowly than the drop in the total current IB, which will result in an effective contribution K2', K3' of the slave modules M2, M3 transiently higher than the desired contribution K2, K3.When this difference in contribution is detected, the bandwidth BE of the slave modules M2, M3 is increased in order to accelerate the decrease of their output current IB2, IB3 and thus prevent too high an overvoltage on the output bus 126.

[0062] For example, the control device 1181, 1182, 1183 comprises a block 412 designed to calculate a difference between the contribution Kl, K2, K3 and the effective contribution Kl', K2', K3' and a hysteresis block 414 on this difference. Thus, when the effective contribution Kl', K2', K3' is smaller than the contribution Kl, K2, K3 by a first threshold (for example zero, the condition is then: Kn - Kn' > 0), the coefficient Kp and / or the coefficient Ki is modified from a low value to a high value. When the effective contribution Kl', K2', K3' is greater than the contribution Kl, K2, K3 of a second threshold (for example 0.05, the condition is then Kn - Kn' < 0.05), the coefficient Kp and / or the coefficient Ki is modified from the high value to the low value. For example, the high value of the coefficient Kp is one hundred times the low value of the coefficient Kp.

[0063] With reference to [Fig. 5], each control device 118i, 1182, 1183 is for example a computer system comprising a data processing unit 502 (such as a microprocessor) and a main memory 504 (such as a RAM memory, from the English “Random Access Memory”) accessible by the processing unit 502. The computer system further comprises for example a network interface and / or a computer-readable medium, such as for example a local medium (such as a local hard disk 506) or a remote medium (such as a remote hard disk accessible via the network interface through a communication network) or a removable medium (such as a USB key, from the English "Universal Serial Bus", or a CD, from the English "Compact Disc" or a DVD, from the English "Digital Versatile Disc") readable by means of an appropriate reader of the computer system (such as a USB port or a CD and / or DVD disk reader). A computer program 508 containing instructions for the processing unit 502 is recorded on the medium 506 and / or downloadable via the network interface. This computer program 508 is for example intended to be loaded into the main memory 504, so that the processing unit 502 executes its instructions. In particular, the blocks described with reference to Figures 3 and 4 may be implemented as software blocks in the computer program 508.

[0064] Alternatively, all or part of these blocks could be implemented in the form of hardware blocks, that is to say in the form of an electronic circuit, for example micro-wired, not involving a computer program.

[0065] In conclusion, it appears clearly that a modular electrical conversion system such as that described above makes it possible to improve the bandwidth for voltage regulation.

[0066] 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 light of the teaching which has just been disclosed to them.

[0067] In particular, the setpoints IB1*, IB2*, IB3* for the slave modules M1, M2, M3 could be calculated from the measurement IB1', IB2', IB3' of the output current IB1, IB2, IB3 of the master module M1, M2 M3, for example, for each slave module M1, M2, M3, as the product of a coefficient K1, K2, K3 associated with this slave module by the measurement IB1', IB2', IB3' of the output current IB1, IB2, IB3 of the master module M1, M2 M3.

[0068] In the detailed presentation of the invention which is made above, 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 all equivalents whose prediction 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

Claims

1. Modular electrical conversion system (114) comprising: - several electrical conversion modules (Ml, M2, M3) each comprising: • a switching circuit (116b 1162, 1163) with an input (120b 1202, 1203) for receiving an input voltage (UA) and an output (122b 1222, 1223) for presenting an output voltage and providing an output current (IB1, IB2, IB3), and • a control device (1181, 1182, 1183) for the switching circuit (116i, H62, 1163); - an output bus (126) to which the outputs (122b 1222, 1223) are connected, so that the output voltages are all equal to a voltage (UB) of the output bus (126); in which the control device (118i) of one of the modules, called master module (Ml), the other module(s) being called slave modules (M2, M3), is designed to implement a closed-loop control, called master control (302), designed to provide a command (Cl) for modifying the output current (IB1), in order to control the voltage (UB) of the output bus (126) to a setpoint (UB*), from a measurement (UB') of the voltage (UB) of the output bus (126); characterized in that: - the control device (1181) of the master module (Ml) is designed to apply the command (Cl) to the switching circuit (116i) without controlling the output current to this command (Cl); - it further comprises a setpoint calculation system (403) designed to calculate, for each slave module (M2, M3), a setpoint (IB2*, IB3*) of its output current (IB2, IB3) from a measurement (IBU) of the output current (IB1) of the master module (M1) or from a measurement (IB') of a total current (IB) supplied to the output bus (126) by all the modules (M1, M2, M3), so that the sum of the setpoints (IB2*, IB3*) is less than the total current (IB); and - the control device (1182, 1183) of each module slave (M2, M3) is designed to implement a closed-loop control, called slave control (402), designed to provide a command (C2, C3) for modifying the output current (IB2, IB3), in order to control the output current (IB2, IB3) to the setpoint (IB2*, IB3*) calculated from a measurement (IB2', IB3') of the output current (IB2, IB3), the control device (118i, 1182) being designed to apply the command (C2, C3) to the switching circuit (116b 1162).

2. Modular electrical conversion system (114) according to claim 1, wherein the master servo (302) is adapted to have a bandwidth (BM) and wherein the slave servo (402) is adapted to have a bandwidth (BE) at least ten times smaller than that of the master servo (302), when the total current (IB) increases.

3. Modular electrical conversion system (114) according to claim 2, wherein the slave servo (402) is designed so that its bandwidth (BE) is substantially equal to that of the master servo (302), when the total current (IB) decreases.

4. Modular electrical conversion system (114) according to claims 2 and 3 taken together, wherein the slave servo (402) is adapted to modify its bandwidth (BE) as a function of the total current (IB) with a hysteresis cycle.

5. Modular electrical conversion system (114) according to any one of claims 1 to 4, in which the setpoint (IB2*, IB3*) of the output current (IB2, IB3) of each slave module (M2, M3) is taken equal to the total current (IB) divided by the number of modules (M1, M2, M3).

6. Modular electrical conversion system (114) according to any one of claims 1 to 5, in which the setpoint (IB2*, IB3*) of the output current (IB2, IB3) of each slave module (M2, M3) is calculated as the product of a contribution (K2, K3) by the total current (IB), the sum of the contributions (K2, K3) being less than one, or as the product of a contribution (K2, K3) by the output current (IB1) of the master module (M1).

7. Modular electrical conversion system (114) according to one any of claims 1 to 6, wherein the contributions (K2, K3) are predefined in each slave module (M2, M3).

8. Modular electrical conversion system (114) according to any one of claims 1 to 7, wherein each slave module (M2, M3) is adapted to receive its contribution (K2, K3) from an external device, for example the master module (Ml) or a device distinct from the modules (Ml, M2, M3).

9. A modular electrical conversion system (114) according to any one of claims 1 to 8, wherein each module (M1, M2, M3) is configured to selectively be the master module and the or one of the slave modules.

10. Modular electrical conversion system (114) according to any one of claims 1 to 9, wherein the modules (M1, M2, M3) are DC-DC or AC-DC or DC-AC converters.

11. A modular electrical conversion system (114) according to any one of claims 1 to 10, further comprising an input bus (124) to which the inputs (120i, 1202, 1203) are connected, such that the input voltages are all equal to a voltage (UA) of the input bus (124).

12. A mobility device (100) comprising a modular electric conversion system (114) according to any one of claims 1 to 11

13. d 11. Mobility device (100) according to claim 12, wherein the modular electrical conversion system (114) is according to claim 11, comprising: - a direct voltage source (106) connected to the input bus (124); and - at least one equipment (112) connected to the output bus (126).

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