Power supply system for a control circuit of a power component and associated inverter

Abstract

A power supply system (4, 4H, 4L) for a close-range control circuit (3H, 3L) of power electronic components (2H, 2L), comprising a transformer (6) equipped with at least one pair of electrostatic screens (9, 10), the power supply system (4, 4H, 4L) being configured such that in a first operating mode, said at least one pair of electrostatic screens (9, 10) is configured as a means for capacitively coupled data exchange, and that in a second operating mode, said at least one pair of electrostatic screens (9, 10) is configured as a common-mode current redirection means capable of redirecting the current flowing in each electrostatic screen (9, 10) to a respective electrical ground (12a, 12b). Figure for the abbreviation: Fig 2

Description

Title of the invention: Power supply system for a control circuit of a power component and associated inverter Technical field

[0001] The invention relates, in general, to electrical systems for power electronics, and relates more particularly to a power supply system isolated from a control circuit of a power component.

[0002] The invention applies in particular to the field of on-board electrical systems in a context of development of more electric vehicles or aircraft, with a need to have reliable, modular and efficient energy conversion systems, and relates in particular to a system for supplying a control circuit in a power conversion module, such as an inverter arm. Previous techniques

[0003] Switching power structures use, in a known manner, a close control circuit, also called a "gate driver", in order to control power components such as transistors or thyristors.

[0004] For example, an inverter, which generates alternating voltages and currents from direct voltages or currents, comprises power components such as power transistors which are controlled by close control circuits to apply to them an operating instruction developed by a global control module of the inverter.

[0005] For safety reasons, these close control circuits generally require the establishment of galvanic isolation between a primary side which is connected to a low voltage electrical circuit, this circuit comprising the global control module, one of the functions of which is to calculate and generate switching orders intended for the power components, and a secondary side which is connected to a high voltage electrical circuit, this circuit comprising the power components to be controlled.

[0006] Galvanic isolation can be achieved in different ways and in particular, in a known manner, by means of a transformer arranged in the power supply system of the close control circuit.

[0007] The insertion of such a transformer in the power supply system of the close control circuit has the effect of inducing parasitic capacitances between the primary and secondary sides contributing to the common mode path of the current. However, in the secondary side, the control of the power components induces sudden dV / dt variations in the potentials, while the primary side is sensitive to electromagnetic disturbances. The sudden variations in potentials at the secondary cause a placement of common mode current from the secondary side to the primary side of the close control circuit via these parasitic capacitances.

[0008] The higher the stray capacitances, the greater the common mode current, which causes electromagnetic compatibility problems known as EMC on the primary side which can disrupt and cause faults in the control of the control circuit. These disturbances are more problematic when the power components are based on wide gap semiconductor transistors, because the dV / dt values ​​are more critical.

[0009] We thus seek to reduce as much as possible the parasitic capacitances induced by the transformer.

[0010] Furthermore, wide gap semiconductor transistors are also very sensitive to the effects of parasitic elements (parasitic capacitance between the primary and secondary sides of the control circuit, parasitic inductance between the control circuit and the power transistor, etc.), with effects on the number of switching operations that they are capable of supporting (aging), as well as disturbances in the control signal of the power transistor. However, wide gap semiconductor transistors are particularly suitable for power electronics, in particular due to their ability to reduce power losses and support higher DC supply voltages, their higher efficiency contributing to a less severe constraint in terms of the need for heat dissipation and therefore reduced size and mass.

[0011] For these reasons, additional considerations have been given to protecting wide gap transistors from the effects of these parasitic elements, and to monitoring their state of health with the aim of anticipating the occurrence of a failure.

[0012] Thus, while conventional close control circuits had the main function of transmitting switching orders through galvanic isolation to apply them to the power components, the current trend is towards so-called intelligent close control circuits, providing additional functions, and in particular integrating a data exchange system between the primary and secondary sides, with the aim of enabling predictive maintenance of the power transistors, as for example described in the publication “A bidi-rectional communicating power supply circuit for smart Gate Driver boards” by J. Weckbrodt et al., IEEE Power Electronics Regular Paper / Letter / Correspondence. Data exchanged via this bidirectional channel include in particular the control order of a gate leakage current measurement circuit, and the voltage measurement data of the power transistor, in particular the gate source voltage.All this requires also ensuring galvanic isolation associated with this data exchange function between the primary and secondary parts.

[0013] Solutions propose to integrate additional galvanic isolation stages in order to protect these data communications, which has the consequence of adding unwanted parasitic capacitances.

[0014] Other solutions use expensive and bulky fiber optic data communications.

[0015] Finally, other solutions such as that described in the aforementioned publication “A bidi-rectional communicating power supply circuit for smart Gâte Driver boards” by J. Weckbrodt et al., IEEE Power Electronics Regular Paper / Letter / Correspondence, consist of modifying the control signals of the switches supplying the transformer windings.

[0016] None of these solutions appears to be totally satisfactory and, in particular, none of them allows both the support of large variations dV / dt of potential between the primary and secondary sides of the close control circuit, the supply of the power necessary to drive the power components (transistors), and the provision of a satisfactory data transmission rate between the primary and secondary sides.

[0017] In view of the above, the present invention aims to propose a power supply system for a control circuit of power semiconductor components avoiding EMC problems while allowing data communication between the primary and secondary sides of the close control circuit with a satisfactory throughput without adding an additional galvanic isolation stage.

[0018] The invention therefore relates to a system for supplying a close control circuit for electronic power components, comprising a transformer equipped with at least one pair of electrostatic screens.

[0019] The power supply system is configured such that, in a first operating mode, said at least one pair of electrostatic screens is configured as a means for exchanging data by capacitive coupling, and that, in a second operating mode, said at least one pair of electrostatic screens is configured as a means for redirecting the common mode current capable of redirecting a current flowing in each electrostatic screen to a respective electrical ground.

[0020] Advantageously, the transformer forms galvanic isolation for the transfer of power supply energy to the close control circuit.

[0021] Preferably, the transformer comprises a primary coil and a secondary coil, each pair of electrostatic screens being arranged between the primary and secondary coils and comprising a primary screen arranged in the vicinity of the primary coil and a secondary screen arranged in the vicinity of the secondary coil and opposite said primary screen, the primary screen being connected to a first data transmission and reception module and the secondary screen being connected to a second data transmission and reception module.

[0022] Advantageously, each primary electrostatic screen is connected to a ground on the primary side and each secondary electrostatic screen is connected to a ground on the secondary side by a respective switch controlled by a switch control system.

[0023] Preferably, in the second operating mode, each of the switches associated with each primary screen is controlled in the closed state by the switch control system.

[0024] Preferably, in the first mode of operation, for each pair of electrostatic screens, the primary electrostatic screen is capacitively coupled to the corresponding secondary electrostatic screen, each switch being controlled in the open state by the switch control system.

[0025] Thus, in the first mode of operation of the proposed power supply system, each pair of electrostatic screens forms a capacitance which allows a transfer of data, by capacitive coupling, between the primary and secondary sides of the control circuit and, in the second mode of operation, the screens of each pair, each being connected one to a ground on the primary side of the control circuit, the other to a ground on the secondary side of the control circuit, make it possible to avoid propagating a common mode current towards the primary side of the control circuit.

[0026] Advantageously, the data exchanged in the first operating mode are modulated at high frequency relative to an operating frequency of the transformer.

[0027] In one embodiment, the data comprises information regarding the health status of a power transistor or measurement information (drain source voltage, drain source current of the power transistor).

[0028] The invention also relates to a power converter comprising a system for supplying a close control circuit as defined above.

[0029] Advantageously, the power converter comprises a power conversion branch comprising at least a first and a second power component connected in series, the power components each being controlled respectively by a first and a second close control circuit from instructions produced by a global control module, and the first and the second close control circuit being respectively powered by a first and a second power supply system as defined above.

[0030] Preferably, the first and second power components comprise wide gap power transistors. Brief description of the drawings

[0031] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the appended drawings in which:

[0032] [Fig-1] illustrates an electrical diagram of an inverter arm;

[0033] [Fig.2] illustrates a diagram of a power supply system of a control circuit according to the invention in the first operating mode;

[0034] [Fig.3] illustrates the power supply system of [Fig.2] in the second mode of operation;

[0035] [Fig.4] illustrates the evolution of signals at characteristic points of the power supply system of [Fig.2]. Detailed description of at least one embodiment

[0036] [Fig.l] schematically shows a conventional power switching electronic structure, such as a power converter 1.

[0037] This power structure 1 conventionally comprises power components such as power transistors 2H and 2L driven respectively by close control circuits 3H and 3L.

[0038] The power structure 1 also comprises power supply systems 4H and 4L respectively of the close control circuits 3H and 3L.

[0039] The power structure 1 is controlled in a conventional manner by a global control module 5 such that, on instructions from this global control module:

[0040] - the 4H power supply system delivers a supply voltage V3H to the circuit of control 3H, and the power supply system 4L delivers a supply voltage V3L to the control circuit 3L; and

[0041] - the close control circuits 3H and 3L powered, drive the transistors of power 2H and 2L by applying respective switching control signals to them, noted VgH for circuit 3H and VgL for circuit 3L.

[0042] More precisely, in the power structure 1 illustrated in [Fig.l], the power transistors 2H and 2L correspond to the power transistors commonly called “High side” (at the top) and “Low side” (at the bottom) of a switching module of the power structure 1, for example an inverter arm.

[0043] Such a power structure 1 comprises a primary side under low supply voltage VCC, corresponding to the logic commands, comprising the global control module 5 which controls the close control circuits 3H and 3L, and a primary side of the supply circuits 4H and 4L by means of respective control signals.

[0044] The power structure 1 also comprises a secondary side under high voltage VDC, corresponding to the power electronics itself, comprising a secondary side of the power supply circuits 4H and 4L> the power transistors 2H and 2l, and the close control circuits 3H and 3L of the power transistors.

[0045] Each of the close control circuits 3H and 3L is powered by a respective positive voltage V3H and V3L delivered by the respective power supply system 4H and 4L; and is driven by the low voltage control (logic control), typically less than 20V, delivered by the global control module 5, to apply the control signals VgH and VgL to the power transistors 2H and 2L.

[0046] VSW is a midpoint between the power transistors 2H and 2L on the high voltage side. The midpoint VSW establishes a voltage, also noted VSW here, which corresponds to the ground of the close control circuits 3H.

[0047] In practice and in a known manner, the power supply of the close control circuits 3H and 3L is floating, so that the control voltages VgH and VgL of the power transistors 2H and 2L which are connected in series between the high voltage VDC and a ground on the secondary side, are established at a required level, relative to the voltage VSW at the midpoint of connection VSW between the two transistors 2H and 2L.

[0048] Thus, as schematically illustrated in [Fig.l], it is necessary to provide a first galvanic isolation 71 for the transfer of the control signal between the global control circuit 5 and the control input of the close control circuits 3H and 3l, generally carried out by an optocoupler or a transformer; and a second galvanic isolation 72, from the power supply system, for the transfer of power supply energy of the close control circuits 3H and 3L, carried out by a transformer in each of the power supply systems 4H and 4L.

[0049] In the following, to facilitate the presentation, and with reference to FIGS. 2 and 3, a power supply system 4 such as the power supply systems 4H and 4L, of a close control circuit such as the control circuits 3H and 3Lj driving a power component such as the power transistors 2H and 2L, is considered.

[0050] As explained above in connection with [Fig.l], the power supply system 4 comprises a transformer 6 providing galvanic isolation 72>

[0051] More precisely, the transformer 6 of the power supply system 4 is configured to provide, on the one hand, the power supply of the close control circuit such as the circuits 3H and 3L ([Fig.l]), and on the other hand to provide the galvanic isolation 72 for the transfer of power supply energy for this close control circuit.

[0052] In the remainder of the description and in the drawings, the following convention is used: the elements arranged on the primary side are marked with an index “a”, and those arranged on the secondary side with an index “b”.

[0053] With reference to Figures 2 and 3, the transformer 6 comprises a primary part including a primary coil 8a. The primary part is powered by the supply voltage VCC (supply voltage on the primary side of the power structure), and receives a control signal Vcomd_tranSf_H / L ([Fig.l]) delivered by the circuit global control module 5 for controlling switches supplying the primary coil 8a. More precisely, in the example illustrated in [Fig.l], a control signal Vcomd_transf_H is thus delivered by the global control module 5 to a primary coil of a transformer of the power supply system 4H, and a control signal Vcomd transf_L is likewise delivered by the global control module 5 to a primary coil of a transformer of the power supply system 4L

[0054] The transformer 6 further comprises a secondary part including a secondary coil 8b; this secondary part provides a supply voltage V3H / i of the associated close control circuit (close control circuits 3H and 3L in [Fig.l]) and ensures the transfer of energy for the control of the power transistors 2h and 2l, by the secondary coil 8b. The galvanic isolation 72 is thus achieved by the two primary 8a and secondary 8b coils of the transformer 6.

[0055] The transformer 6 comprises at least one pair of electrostatic screens, comprising a primary screen arranged on the primary side and a secondary screen arranged on the secondary side, the pair of screens being arranged between the primary 8a and secondary 8b coils, each screen of the pair 9 being opposite one another.

[0056] In the example illustrated in Figures 2 and 3, the transformer 6 more particularly comprises two such pairs of electrostatic screens 9 and 10 arranged between the coils 8a and 8b. The first pair 9 of screens thus comprises a primary screen 9a and a secondary screen 9b, and the second pair 10 of screens comprises a primary screen 10a and a secondary screen 10b.

[0057] The primary and secondary screens of each pair 9 and 10 are arranged opposite each other, the primary screen 9a and 10a being arranged in the vicinity of the primary coil 8a and the secondary screen, 9b and 10b being arranged in the vicinity of the secondary coil 8b.

[0058] The power supply system 4 further comprises a switching device 11 comprising a primary 9a and 10a and secondary 9b and 10b electrostatic screen switch, the switching device 11 making it possible to control a first or a second operating mode of the power supply system 4. In one example, the switches of the switching device 11 are silicon transistors.

[0059] In the first mode of operation of the power supply system 4, illustrated in [Fig. 2], the pairs of electrostatic screens are configured as means for exchanging data by capacitive coupling, and in the second mode of operation illustrated in [Fig. 3], the pairs of electrostatic screens are configured as means for redirecting the common mode current.

[0060] In more detail, in the first mode of operation of the power supply system 4 illustrated in [Fig.2], the switches of the switching device 11 are simultaneously switched to the open state, and each pair of electro shields static is then capable of allowing a transfer of data between two data transmission and reception modules 13a and 13b (primary side) and (secondary side) (detailed later in the description), by capacitive coupling.

[0061] More particularly, in this first mode of operation of the power supply system 4, the two pairs of screens 9 and 10 allow a bidirectional exchange of data, from the primary to the secondary and vice versa.

[0062] In the second mode of operation of the power supply system 4 illustrated in [Fig. 3], the switches of the switching device 11 are simultaneously switched to the closed state, which has the effect of connecting the primary screens 9a and 10a to a first ground 12a arranged on the primary side, and the secondary screens 9b and 10b to a second ground 12b arranged on the secondary side.

[0063] More precisely, the primary screens 9a and 10a of each pair 9 and 10 are each connected by a respective switch Sla and S2a to the first ground 12a arranged on the primary side, and the secondary screens 9b and 10b of each pair 9 and 10 are each connected by a respective switch Slb and S2b to the second ground 12b arranged on the secondary side.

[0064] We have seen that the two screens of each pair 9 and 10, respectively the primary screen and the secondary screen, are capacitively coupled in the first operating mode. We note Cl the capacitance associated with the pair 9 and C2 that associated with the pair 10 in the example of [Fig.2].

[0065] Furthermore, with the integration of these pairs of screens 9 and 10 between and near the coils 8a and 8b, a parasitic capacitance is induced between each screen and the nearby coil, both on the primary side and the secondary side.

[0066] We thus note, Cia and Clb the parasitic capacitances induced respectively between the primary screen 9a and the coil 8a and between the secondary screen 9b and the coil 8b.

[0067] Similarly, C2a and C2b denote the parasitic capacitances induced respectively between the primary screen 10a and the coil 8a and between the secondary screen 10b and the coil 8b.

[0068] In other words, the galvanic isolation 72 provided by the coils 8a and 8b of the transformer 6 induces parasitic capacitances Cia, C2a, Clb and C2b contributing to the common mode current flowing through the pairs of electrostatic screens 9 and 10 and which can cause EMC problems, as described previously.

[0069] Each of the switches Sla and S2a of the switching device 11 arranged on the primary side is individually controlled by a primary switch control system 14a of the switching device 11 and each of the switches Slb and S2b of the switching device 11 arranged on the secondary side is individually controlled by a secondary switch control system 14b of the switching device 11.

[0070] The switches Sla, Slb, S2a and S2b associated with the primary screens 9a and 10a and secondary 9b and 10b of the pairs of electrostatic screens 9 and 10 thus make it possible to configure the power supply system 4 of the power circuit in a first operating mode corresponding to a data communication mode by capacitive coupling between primary and secondary transmission / reception circuits, or in a second operating mode, in which the primary and secondary electrostatic screens are actively connected to their respective primary 12a and secondary 12b ground, making it possible to redirect the unwanted common mode current towards the ground 12b of the secondary.

[0071] More specifically, when the switches Sla, Slb, S2a and S2b are all controlled to the open state by their corresponding control system 14a and 14b as illustrated in [Fig.2], the power supply system 4 is configured to operate according to the first operating mode. Indeed, the electrostatic screens 9a, 9b, 10a and 10b are not connected to the respective grounds 12a or 12b and can exchange data.

[0072] Conversely, when the switches are all controlled to the closed state by their corresponding control system 14a and 14b as illustrated in [Fig. 3], the power supply system 4 is configured to operate according to the second operating mode.

[0073] The power supply system 4 for the close control circuit 3 further comprises, as specified above in the description, a first data transmission and reception module 13a arranged on the primary side and a second data transmission and reception module 13b identical to the first and arranged on the secondary side.

[0074] The modules 13a and 13b are connected by wire respectively to each of the primary screens 9a and 10a and the secondary screens 9b and 10b. More precisely, the wired connection between the first module 13a and the primary screen 9a is a data transmission channel for the first module 13a and that between the first module 13a and the primary screen 10a is a data reception channel for the first module 13a. Similarly, the wired connection between the second module 13b and the secondary screen 9b is a data reception channel for the second module 13b and that between the second module 13b and the secondary screen 10b is a data transmission channel for the second module 13b.

[0075] Each of the modules 13a and 13b is capable of modulating and demodulating data to be transmitted or received via the transformer 6. Thus, as previously explained, when the screens of two pairs 9 and 10 are all isolated from their respective ground 12a and 12b, the switches Sla, Slb, S2a and S2b all being controlled in the open state, the modules 13a and 13b allow bidirectional communication of the information data between the primary and secondary sides of the power supply system 4 of the close control circuit. This is the first mode of operation. This Data communication is used to exchange data representative of the health status, such as temperature measurements, drain-source voltage or gate-source voltage measurements of the 2H and 2L power transistors, and control commands for the circuits enabling these close measurements.

[0076] In practice, the data sent by the modules 13a and 13b are modulated at high frequency relative to the operating frequency of the transformer 6, in order to limit the impact of the parasitic capacitances Clb, Cia, C2b, C2a between the screens and the coils of the transformer 6. For example, the data sent are modulated at a frequency of 10 MHz.

[0077] Thus, the proposed power supply system 4 with its pairs of electrostatic screens 9 and 10 and its switches Sla, S2a, Slb and S2b making it possible to isolate or on the contrary to connect the primary and secondary screens of each pair 9 and 10 to a corresponding ground 12a and 12b, thus makes it possible to configure the power supply system 4 in a first operating mode as a means of transferring data by capacitive coupling, in which said switches Sla, S2a, Slb and S2b are controlled in the open state, and in a second operating mode as a means of rejecting the current induced in the primary 9a and 10a and secondary 9b and 10b screens by the associated parasitic capacitances Clb, Cia, C2b, C2a towards the ground of the primary 12a and the secondary 12b respectively, said switches Sla, S2a, Slb and S2b being controlled in the open state. the closed state.

[0078] The two operating modes are illustrated in [Fig. 4], representing a graph illustrating the evolution as a function of time of the data transmission frames 15 (curve A) by the modules 13a and 13b, of the power supply control signals Vcomd transf_H / L of the primary winding of the transformer 6 (curve B), of the control signals VgH / L of the power transistors 2H and 2L supplied by the close control circuits 3H, 3L (curve C), and the evolution of the variation of the potential of the midpoint VSW between the power transistors 2H and 2L of the illustrated example of an inverter arm (curve D).

[0079] More precisely, between the instants t0 and tl, there is no sudden variation in potential dV / dt, and the first operating mode is activated. This means that the switches Sla, S2a, Slb and S2b of the switching device 11 are open and that data frames 15 are exchanged.

[0080] Conversely, between times t1 and t2, the switching to the OFF state of the power transistors 2H and 2L occurs, causing a sudden variation in potential dV / dt of the drain-source voltage at the terminals of the power transistors 2H and 2L. It is in these switching phases of the power transistors corresponding to sudden voltage variations (high dV / dt) that the second operating mode is activated. During these phases, the switches Sla, S2a, Slb and S2b are all controlled simultaneously. tangent to the closed state so that the common mode current induced on the primary 9a and 10a and secondary 9b and 10b screens by the stray capacitances is redirected to the corresponding ground of the primary 12a or secondary 12b of these screens. In this way, the unwanted common mode current due to the strong potential variations on the secondary side no longer flows to the primary, but is directed to the ground 12b of the secondary, thus avoiding EMC malfunctions. During this time, no data frame 15 is exchanged between the primary and secondary sides.

[0081] The duration of an operating cycle corresponding to the second operating mode is in practice very short, of the order of the duration of the sudden variation in potential dV / dt. Apart from these short cycles, of the order of a few hundred nanoseconds, corresponding to the occurrences of sudden variations in potential dV / dt, the power supply system 4 is in the first operating mode. In other words, this switching making it possible to manage the common mode current in a particularly efficient manner has almost no impact on the data exchange rate between the primary and secondary transmission / reception modules 13a and 13b.

[0082] Thus, since the transformer 6 comprises at least two pairs of electrostatic screens 9 and 10, the power supply system 4 allows in the first operating mode to carry out bidirectional data exchanges between the primary and secondary sides of the power supply system 4 of the close control circuit 3H and 3L, and in the second operating mode to reduce the effects of a strong variation in potential dV / dt in the secondary side, thus eliminating possible EMC problems.

[0083] The power supply system 4 allowing a bidirectional exchange of data by capacitive coupling via pairs of electrostatic screens 9 and 10 is efficient in terms of EMC. It does not require additional insulation components which have the disadvantage, as explained in the introduction, of bringing new parasitic capacitances.

[0084] The power supply system 4 sequenced as proposed, also allows better immunity to strong potential variations over time by the use of such pairs of electrostatic screens 9 and 10.

[0085] Finally, the power supply system 4 according to the invention allows a high data transfer rate between the primary and the secondary of the control circuit 3, the duration of the second operating mode being very short, of the order of a few hundred nanoseconds and equivalent to the duration of sudden variation in potential.

[0086] The invention has more particularly been described for power components of the power transistor type and more particularly so-called wide gap transistors, for which health monitoring proves to be particularly important; but the invention applies more generally to any technology of power transistors or power electronic switches, and makes it possible both to satisfy data exchange functions between the primary and secondary sides of a power system in a power converter and to resolve efficiently, at lower integration cost, the problems associated with the circulation of common mode currents.

Claims

Claims

1. Power supply system (4, 4H, 4L) for a close control circuit (3h, 3l) of power electronic components (2H, 2L), comprising a transformer (6) equipped with at least one pair of electrostatic screens (9, 10), characterized in that the power supply system (4, 4H, 4l) is configured such that, in a first operating mode, said at least one pair of electrostatic screens (9, 10) is configured as a means for exchanging data by capacitive coupling and that, in a second operating mode, said at least one pair of electrostatic screens (9, 10) is configured as a means for redirecting the common mode current capable of redirecting a current flowing in each electrostatic screen (9, 10) to a respective electrical ground (12a, 12b).

2. A power supply system (4, 4H, 4L) according to claim 1, wherein the transformer (6) forms a galvanic isolation (72) for the transfer of power supply energy from the close control circuit (3

3. H, JÜ- Power supply system (4, 4H, 4L) according to claim 1 or 2, wherein the transformer (6) comprises a primary coil (8a) and a secondary coil (8b), each pair of electrostatic screens (9, 10) being arranged between the primary (8a) and secondary (8b) coils and comprising a primary screen (9a, 10a) arranged in the vicinity of the primary coil (8a) and a secondary screen (9b, 10b) arranged in the vicinity of the secondary coil (8b) and opposite said primary screen (9a, 10a), the primary screen (9a, 10a) being connected to a first data transmission and reception module (13a) and the secondary screen (9b, 10b) being connected to a second data transmission and reception module (13b).

4. A power supply system (4, 4H, 4L) according to claim 3, wherein each primary electrostatic shield (9a, 10a) is connected to a ground on the primary side (12a) and each secondary electrostatic shield (9b, 10b) is connected to a ground on the secondary side (12b) by a respective switch (Sla, Slb, S2a, S2b) controlled by a switch control system (14a, 14b).

5. A power supply system (4, 4H, 4L) according to claim 4, wherein in the second mode of operation, each of the switches (Sla, Slb, S2a, S2b) associated with each primary screen is controlled to the closed state by the switch control system (14a, 14b).

6. A power supply system (4, 4H, 4L) according to claim 4 or 5, wherein in the first mode of operation, for each pair of electrostatic screens (9, 10), the primary electrostatic screen (9a, 10a) is capacitively coupled to the corresponding secondary electrostatic screen (9b, 10b), each switch (Sla, Slb, S2a, S2b) being controlled in the open state by the switch control system (14a, 14b).

7. A power supply system (4, 4H, 4L) according to any one of claims 1 to 6, wherein the data exchanged in the first operating mode is modulated at high frequency relative to an operating frequency of the transformer (6).

8. Power converter comprising a power supply system (4, 4 H, 4 l) of a close control circuit (3) according to any one of claims 1 to 7.

9. Power converter according to claim 8, comprising a power conversion branch comprising at least a first and a second power component (2H, 2L) connected in series, the power components (2H, 2L) each being controlled respectively by a first and a second close control circuit (3H, 3L) from instructions produced by a global control module (5), the first and the second close control circuit (3H, 3L) being respectively supplied by a first and a second power supply system (4H, 4L) according to any one of claims 1 to 7.

10. A power converter according to claim 9, wherein the first and second power components (2H, 2L) comprise wide gap power transistors.

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