Short-circuit protection method for a MOSFET power converter connected to a DC power supply network

Abstract

Short-circuit protection method for a MOSFET power converter connected to a DC power supply network. Control method for a power converter connected to a DC voltage network and comprising a rotating electrical machine, the converter comprising parallel electric arms, each equipped with at least two MOSFETs, and a control circuit comprising a protection module configured to prohibit simultaneous conduction of the MOSFETs of the same arm.The method comprises: - detection (410) of a short circuit on said network, then - deactivation (420) of the protection module, and - control (430) of the MOSFETs in an ideal diode mode in which each MOSFET conducts as soon as the voltage across its terminals is negative, thus causing simultaneous conduction of the MOSFETs of the same leg when the current through the filter inductor is greater than the current delivered by the electrical machine, and a synchronous rectification mode once the current is lower. Figure for the abbreviation: Fig. 4.

Description

Title of the invention: Short-circuit protection method for a MOSFET power converter connected to a DC power supply network technical field

[0001] The invention relates to voltage converters equipped with MOSFET semiconductors and connected between a DC voltage power supply network and a rotating machine such as an electric or hybrid electric motor / generator, and more particularly to a method of short-circuit protection of an electrical circuit equipped with such a converter. Previous technique

[0002] Figure 1 shows a typical power circuit architecture for a rotating machine 1. The typical architecture comprises a rotating machine 1 of the motor / generator type and a semiconductor power converter 2 connected between the rotating machine 1 and a direct current (DC) electrical network 3. The semiconductors of the power converter 2 are insulated-gate field-effect transistors 4, more commonly known as MOSFETs (metal-oxide-semiconductor field-effect transistors), assembled to form three parallel electrical branches 5, each comprising two MOSFETs 4 connected in series. Each electrical branch 5 is coupled to one phase of the rotating machine 1.

[0003] The architecture further includes a filter capacitor 6 coupled in parallel with the electrical branches 5, and a filter inductance 7 coupled in series between the DC electrical network 1 and the filter capacitor 6. A wiring resistor 8 has also been shown.

[0004] In this typical architecture, the power converter 2 forms a voltage inverter. The rotating machine 1 to which the converter 2 is electrically coupled is an electrical machine such as a permanent magnet synchronous machine, or PMSM.

[0005] The power converter 2 is controlled by a MOSFET gate control circuit 9. In normal operation, the MOSFETs 4 of the inverter 2 are controlled by the pulse-width modulation (PWM) control circuit to drive the motor (propulsion mode) or to draw power (generator mode) to supply the DC electrical network.

[0006] In the event of a short circuit on the DC network 1 (the DC network power supply in [Fig. 1] is schematically replaced by a cable), the filter capacitor 6 The current discharges abruptly through the short circuit via the inductances of the filter capacitor 7 and the cables. This short circuit creates an oscillating circuit between the filter capacitor 6 and the very weakly damped inductors. The oscillating current, resulting from this oscillating circuit and much greater than the current of the converter 2, reverses the voltage across the filter capacitor 6, causing the intrinsic (reverse) diodes of the MOSFETs to conduct, thus completing the short circuit.

[0007] This short-circuit current can cause MOSFET 4 to break, unless they are oversized or diodes are added in antiparallel.

[0008] Several techniques exist to react in case of network short circuit and discharge the filter capacitor safely.

[0009] A detection circuit for an active discharge circuit of a capacitor is known from US patent 2021 / 0080491. This patent describes a widespread practice of using an active discharge circuit by adding a dedicated circuit in parallel with the inverter. The purpose of this dedicated circuit is to discharge the capacitor in a controlled and safe manner as soon as a fault requiring it is detected. Thus, all the current is absorbed by this circuit, preventing any impact on the other components of the power stage.

[0010] This active discharge solution allows control of the discharge of the filter capacitor in a dedicated circuit in parallel with the network.

[0011] On the other hand, it does not prevent the discharge of the filter capacitor in a short circuit present on the network (the active discharge circuit is in parallel).

[0012] To protect systems from short circuits, it is also known to add components in parallel, such as antiparallel diodes or additional MOSFETs, to conduct the short-circuit current.

[0013] Although this technique is the most used, it generates an additional cost and an increase in the size of the power module.

[0014] Document US006021055, relating to a conversion circuit with synchronous conduction, uses this latter technique with specific loads. The specific loads used require a higher terminal voltage than in nominal operation in order to start, as is the case with discharge lamps. In order to apply a high voltage for a short time, this document proposes applying ideal diode conduction via a synchronous conduction mode of the MOSFETs, with the aim of creating a voltage spike to light a lamp.

[0015] This embodiment, even if it involves synchronous conduction of the MOSFETs for a short time, does not allow the problem of reducing losses in the diodes in the event of a short circuit on the network to be addressed.

[0016] Thus, in the prior art, the management of capacity discharge during Defects such as short circuits are generally addressed either by adding an active discharge circuit or by adding components (additional diodes or MOSFETs in parallel). Both solutions are expensive (in terms of size and cost), either because of the addition of new components or because of the oversizing of existing components to accommodate a malfunction. Description of the invention

[0017] The invention aims to provide a control principle for the MOSFETs of the inverter which limits the losses, and the risk of destruction by self-heating, of the MOSFETs for cases of short circuit on the DC power supply network, while limiting the additional financial cost and the size.

[0018] In other words, the main purpose of the invention is to reduce the thermal stress of the MOSFETs of the power converter during a short circuit on the DC voltage network causing the discharge of capacitances through the MOSFETs.

[0019] In a first object of the invention, a method for controlling a power converter of an electrical system connected to a DC voltage network is proposed in order to protect the electrical system against a short circuit of the DC voltage network.The electrical system comprising a rotating electrical machine and a power converter electrically connected between the DC voltage network and the electrical machine, the power converter comprising electric arms mounted in parallel with each other, a filter capacitor coupled in parallel with the electric arms and a filter inductance connected in series between the filter capacitor and said DC voltage network to which the electrical system is coupled, each electric arm comprising a series arrangement of at least two insulated-gate field-effect transistors, MOSFETs, and the power converter further comprising a MOSFET gate control circuit comprising a protection module configured in particular to prohibit the simultaneous conduction of the MOSFETs of the same arm.

[0020] According to a general feature of the invention, the control method for protecting the electrical system against a short circuit in the DC voltage network comprises the following steps: - detection of a short circuit on the DC voltage network, then - a deactivation of the MOSFET gate control circuit protection module to allow simultaneous conduction of MOSFETs on the same arm, and - activation of a MOSFET gate control in an ideal diode mode in which each MOSFET conducts as soon as the voltage across its terminals is negative. The MOSFET gates are controlled in an ideal diode mode after deactivation. The tivation of the MOSFET gate control circuit protection module results in simultaneous conduction of the MOSFETs of the same arm as long as the current through the filter inductance is greater than the current delivered by the rotating electrical machine, and a resumption of a synchronous rectification mode of the MOSFETs of the same arm once the current through the filter inductance is less than the current delivered by the rotating electrical machine.

[0021] Preferably, the rotating electrical machine is configured to operate in motor mode or in generator mode.

[0022] MOSFETs are conventionally controlled by gate driver circuits, which provide the functions of transmitting control signals to the gate through galvanic isolation, gate control, component protection (desaturation, supply undervoltage, etc.), dead time, and coupling, or interlock, which aims to prevent the simultaneous conduction of MOSFETs in the same arm, which would lead to the short circuit of the DC voltage network capacitor and increased losses or even destruction of the components.

[0023] The method according to the invention allows switching to an ideal diode control mode for MOSFETs following the detection of a short circuit on the DC voltage network. This control makes it possible, in particular, to inhibit the coupling function ("interlock"), and thus to allow operation in a synchronous conduction mode during the energy discharge phase of the capacitors in the DC voltage network.

[0024] The control method thus includes a phase of synchronous conduction of the MOSFETs, which is usually prohibited for voltage converters.

[0025] Reverse conduction of MOSFETs helps to limit losses as shown by the characteristics of the voltage drop between the drain and source of MOSFETs (Drain-Source Voltage VDS) in [Fig.2].

[0026] Indeed, in this example, with MOSFET control (Vgs=15V), the voltage drop in the on-state is on the order of -1.5V for a current of -100A, whereas it is on the order of -4.5V for the same current if the MOSFET is not controlled (Vgs=0V), which allows the losses to be divided by 3.

[0027] This command allows a natural return to synchronous rectification mode when the energy of the capacitors is dissipated.

[0028] Furthermore, the method according to the invention, using a synchronous conduction phase of the MOSFETs, makes it possible to obtain a significant reduction in the junction temperature of the MOSFETs and therefore an increase in their lifespan. Tests have shown that the MOSFETs experience a significant reduction in thermal stress (25 to 36°C reduction at the junction for two strictly identical but with a different MOSFET control).

[0029] The method according to the invention thus offers a solution for protecting against a short circuit in the DC voltage network without having to add or oversize power components. This is achieved by using, under certain conditions, ideal diode conduction.

[0030] Advantageously, the detection of a short circuit on the DC voltage network can include the detection of a voltage drop across the terminals of the DC voltage network via regular iterations of a measurement of the voltage across the terminals of the DC voltage network and a comparison of the measured voltage to a voltage threshold below which the voltage drop corresponds to a short circuit on the DC voltage network.

[0031] In one embodiment, the detection of a short circuit on the DC voltage network may include a continuous measurement of the current on the DC voltage network, and, during operation of the rotating electrical machine in motor mode, a detection of a reversal of the direction of current at the output of the DC voltage network from a detection of the sign of the measured current, and, during operation of the electrical system in generator mode, a detection of an exceedance of a short-circuit current threshold from a comparison of the measured current to a current threshold.

[0032] Advantageously, the activation of a MOSFET gate control in an ideal diode mode can include, for each MOSFET, a measurement of the voltage between the drain and source of the MOSFET, a comparison of the measured voltage between the drain and source of the MOSFET to a zero voltage, and a conduction of the MOSFET as soon as the measured voltage between the drain and source of the MOSFET is negative.

[0033] In one embodiment, the activation of a MOSFET gate control in an ideal diode mode may include, for each MOSFET, a measurement of the current through the MOSFET with a positive direction of measurement from the drain to the source of the MOSFET, a comparison of the measured current to a zero or slightly negative current threshold, and a conduction of the MOSFET as soon as the current is below this threshold.

[0034] In another object of the invention, an electrical system is proposed for connection to a direct current network. The electrical system comprises a rotating electrical machine configured to operate in motor mode or generator mode and a power converter connected between the rotating electrical machine and connection terminals for connection to the direct current network. The power converter comprises electrical arms mounted in parallel with each other and a filtering capacitor connected in parallel with the arms. electrical and a filtering inductance connected in series between the filtering capacitor and one of said connection terminals, each electrical arm comprising a series arrangement of at least two insulated-gate field-effect transistors, MOSFETs, and the power converter further comprising a MOSFET gate control circuit comprising a protection module configured in particular to prohibit the simultaneous conduction of the MOSFETs of the same arm.

[0035] According to a general characteristic of the electrical system according to the invention, in addition to the electrical protection means against a short circuit of the DC voltage network to which the electrical system is intended to be connected, the electrical protection means comprise: - a module for detecting a short circuit on the DC voltage network, - a module for disabling the protection module of the MOSFET gate control circuit controlled by said short-circuit detection module, - at least one MOSFET gate driver module configured to drive at least one MOSFET in an ideal diode mode in which each MOSFET conducts as soon as the voltage across its terminals is negative.

[0036] Controlling the MOSFET gates in an ideal diode mode after deactivation of the protection module of the MOSFET gate control circuit results in simultaneous conduction of the MOSFETs of the same leg as long as the current through the filter inductance is greater than the current delivered by the rotating electrical machine, and a resumption of a synchronous rectification mode of the MOSFETs of the same leg once the current through the filter inductance is less than the current delivered by the rotating electrical machine.

[0037] Preferably, said rotating electrical machine may be a permanent magnet machine controlled in normal operation, without short circuit, by pulse width modulation to drive the motor or to draw power from the generator to supply the DC electrical network.

[0038] Advantageously, the MOSFET gate control circuit may include a control input used in normal, non-short-circuit operation, and a reset input, the reset input being configured to disable the gate control circuit protection module upon receipt of a disable signal.

[0039] Advantageously, the electrical system may include a first MOSFET gate control module for each MOSFET, said first control module comprising a multiplexer having a first input configured to receive a normal operating command for the MOSFET, a second input configured to receive an ideal diode operating command, a selection input, and an output configured to copy the first input as long as no signal has been received on the selection input and to copy the second input to the output of the multiplexer when the selection input receives a selection signal, the selection signal being received when the MOSFET gate driver circuit receives a reset command on its reset input.

[0040] In one embodiment, the electrical protection means may further include means for measuring the voltage across the terminals of the DC voltage network coupled to the connection terminals and means for comparing the measured voltage to a voltage threshold below which the voltage drop corresponds to a short circuit on the DC voltage network, or means for measuring the current flowing on the DC voltage network coupled to one of said connection terminals and means for comparing the measured current to a current threshold. Brief description of the drawings

[0041] The invention will be better understood upon reading the following, by way of example but not limitation, with reference to the accompanying drawings in which:

[0042] [Fig.1] The [Fig.1], already described, represents a schematic representation of an architecture of a power circuit of a rotating machine according to the prior art.

[0043] [Fig.2] The [Fig.2], already described, is a graphical representation of the evolution of the voltage between the drain and the source of a MOSFET as a function of the current between the drain and the source and the voltage between the gate and the source.

[0044] [Fig.3] Fig.3 schematically represents an electrical system according to one embodiment of the invention.

[0045] [Fig. 4] [Fig. 4] shows a flowchart of a method for protecting the electrical system of [Fig. 3] according to one embodiment of the invention. Description of embodiments

[0046] Figure 3 shows an electrical diagram of an electrical system 10 according to an embodiment of the invention.

[0047] The electrical system includes a rotating electrical machine 11 of the permanent magnet type, a power converter 12 having connection terminals 13 configured to be electrically connected to a DC voltage network 30, and an electrical protection block 14 of the electrical system 10 against a short circuit of the DC voltage network 30.

[0048] The power converter 12 comprises three electrical arms 15 connected in parallel with each other. Each electrical arm 15 comprises a series arrangement of two MOSFETs 16 having the same direction of conduction. Each electrical arm 15 comprises an electrical node 17 coupled, on the one hand, to each of the MOSFETs 16 of the arm electric 15, and on the other hand to a phase of the rotating electric machine 11.

[0049] The power converter 12 further includes a filter capacitor 18 mounted in parallel with the electric arms 15, as well as a filter inductance 19 coupled between the filter capacitor 18 and a connection terminal 13. In [Fig.3] a wiring resistor 20 has also been shown.

[0050] The electrical system 1 further includes a MOSFET gate control circuit 40. The MOSFET gate control circuit 40 is configured to transmit control signals to the gate of each MOSFET through galvanic isolation. In particular, under normal operating conditions, i.e., in the absence of a short circuit, it controls the MOSFETs 16 of the power converter 12 to send signals to the electric machine 11 and control it using pulse-width modulation to drive the motor or draw power from the generator to supply the DC power grid.

[0051] The MOSFET gate control circuit 40 further includes a protection module 42 which is configured to manage dead times and arm couplings, called "interlock" in English, and thus prohibit the simultaneous conduction of the MOSFETs 16 of the same arm 15. This prohibition generally prevents the formation of a short circuit in the capacitor of the DC voltage network and the increase in losses or even the destruction of the components.

[0052] The electrical protection block 14 includes a module 141 for detecting a short circuit on the DC voltage network 30, a module 142 for disabling the protection module 42 of the control circuit 40 of the MOSFET gates, and a MOSFET gate control module 143.

[0053] The MOSFET gate control module 143 replaces the MOSFET gate control circuit 40 following the detection of a short circuit on the DC voltage network 30.

[0054] The module 141 for detecting a short circuit on the DC voltage network 30 includes means 145 for measuring the voltage at the connection terminals 13 and means 146 for comparing the measured voltage to a voltage threshold below which the voltage drop corresponds to a short circuit on the DC voltage network 30.

[0055] In one variant, the module 141 for detecting a short circuit on the DC voltage network 30 may include means for measuring the current flowing on the connection terminals 13 and means for comparing the measured current to a current threshold.

[0056] The MOSFET gate control circuit 40 may include a control input used in normal, non-short-circuit operation, and a reset input, the reset input being configured to disable the module protection 42 of the control circuit 40 of the grid upon receipt of a deactivation signal emitted by the deactivation module 142.

[0057] The MOSFET gate control module 143 is configured to drive each of the MOSFETs 16 in an ideal diode mode in which each MOSFET 16 conducts as soon as the voltage across its terminals is negative. The control module 143 is controlled in response to the signal from the deactivation module 142. Driving the MOSFET gates 16 in an ideal diode mode results in simultaneous conduction of the MOSFETs 16 of the same leg 15 as long as the current through the filter inductor 19 is greater than the current delivered by the rotating electrical machine 11, and a resumption of synchronous rectification mode for the MOSFETs 16 of the same leg 15 once the current through the filter inductor 19 is less than the current delivered by the rotating electrical machine 11.

[0058] Figure 4 shows a logic diagram of a method for controlling the power converter 12 of the electrical system 10 to protect the electrical system 10 against a short circuit of the DC voltage network 30 to which the electrical system 10 is intended to be connected, according to an embodiment of the invention.

[0059] The control method according to the embodiment of the invention includes a step 410 of detecting a short circuit on the DC voltage network 30.

[0060] The step of detecting a short circuit on the DC voltage network 30 includes detecting a voltage drop across the terminals of the DC voltage network. The voltage drop is detected by monitoring the voltage across the terminals of the DC voltage network 30. The monitoring is carried out via regular measurements of the voltage across the connection terminals 13, and a comparison of each voltage measurement to a voltage threshold below which the voltage drop corresponds to a short circuit on the DC voltage network.

[0061] In one embodiment, the detection of a short circuit on the DC voltage network 30 includes a continuous measurement of the current on a connection terminal 13, and, during operation of the rotating electrical machine in motor mode, a detection of a reversal of the direction of current at the output of the DC voltage network from a detection of the sign of the measured current, and, during operation of the electrical system in generator mode, a detection of an exceedance of a short-circuit current threshold from a comparison of the measured current to a current threshold.

[0062] The method then includes a step 420 of deactivating the protection module 42 of the control circuit 40 of the MOSFET gates. This deactivation removes the prohibition of simultaneous conduction of the MOSFETs 16 of the same arm 15. Thus, the control method includes a phase of synchronous conduction of the MOSFETs 16, which is usually prohibited for voltage converters.

[0063] Simultaneously with step 420, the method includes a step 430 of activating a control of the MOSFET gates in an ideal diode mode in which each MOSFET 16 conducts as soon as the voltage across its terminals is negative.

[0064] Step 430 of activating a MOSFET gate control in an ideal diode mode includes, for each MOSFET 16, a measurement of the voltage between the drain and the source of the MOSFET 16, a comparison of the measured voltage between the drain and the source of the MOSFET 16 to a zero voltage, and a conduction of the MOSFET 16 as soon as the measured voltage between the drain and the source of the MOSFET is negative.

[0065] Controlling the MOSFET gates 16 in an ideal diode mode thus results in simultaneous conduction of the MOSFETs 16 of the same arm 15 as long as the current through the filtering inductance (step 440) is greater than the current delivered by the rotating electrical machine 11.

[0066] Once the filter inductance 19 is discharged, in step 440, the ideal diode mode operation automatically leads to a resumption of synchronous rectification mode (step 450) of the MOSFETs 16 of the same arm 15. In other words, once the current through the filter inductance is less than the current delivered by the rotating electrical machine 11, synchronous rectification resumes.

[0067] Subsequently, once the fault which caused the short circuit has been dealt with (opening of the circuit by a fuse, a circuit breaker, a contactor,...), the voltage rises again and allows the normal control of the converter to restart as soon as the voltage exceeds a threshold higher than the previous voltage threshold.

[0068] In an unillustrated embodiment, the electrical system 10 may include a plurality of first MOSFET gate control modules. More specifically, it may include one first MOSFET gate control module for each MOSFET. In this configuration, each first control module includes a multiplexer comprising a first input configured to receive a normal MOSFET operating command, a second input configured to receive an ideal diode operating command, a select input, and an output configured to copy the first input as long as no signal has been received on the select input and to copy the second input to the output of the multiplexer when the select input receives a select signal, the select signal being received when the MOSFET gate control circuit receives a reset command on its reset input.

[0069] The invention thus provides a technical solution for controlling MOSFETs of an inverter to limit losses and the risk of destruction by self-heating of the MOSFETs when a short circuit on the DC power supply network occurs, while limiting the additional financial cost and size.

Claims

Claims

1. A method for controlling a power converter (12) of an electrical system (10) connected to a DC voltage network (30) to protect the electrical system (10) against a short circuit of the DC voltage network (30), the electrical system (10) comprising a rotating electrical machine (11) and a power converter (12) electrically connected between the DC voltage network (30) and the rotating electrical machine (11), the power converter (12) comprising electrical arms (15) connected in parallel to each other, a filter capacitor (18) coupled in parallel to the electrical arms (15) and a filter inductance (19) connected in series between the filter capacitor (18) and said DC voltage network (30) to which the electrical system (10) is coupled, each electrical arm (15) comprising a series connection of at least two insulated gate field effect transistors, MOSFETs, (16),and the power converter (12) further comprising a control circuit (40) for the gates of the MOSFETs comprising a protection module (42) configured to prohibit the simultaneous conduction of the MOSFETs (16) of the same arm (15), characterized in that the control method for protecting the electrical system (10) against a short circuit of the direct voltage network (30) comprises the following steps:, - detection (410) of a short circuit on the direct voltage network (30), then - a deactivation (420) of the protection module (42) of the control circuit (40) of the gates of the MOSFETs (16) to authorize the simultaneous conduction of the MOSFETs (16) of the same arm (15), and - an activation (430) of a control of the gates of MOSFETs (16) in an ideal diode mode in which each MOSFET (16) conducts as soon as the voltage at its terminals is negative.

2. The method of claim 1, wherein detecting (410) a short circuit on the DC voltage network (30) comprises detecting a voltage drop across the DC voltage network (30) via regular iterations of measuring the voltage across the DC voltage network (30) and comparing the measured voltage to a voltage threshold below which the voltage drop corresponds to a short circuit on the DC voltage network. (30).

3. Method according to claim 1, in which the detection (410) of a short circuit on the direct voltage network (30) comprises a continuous measurement of the current on the direct voltage network (30), and, during operation of the rotating electrical machine (11) in motor mode, a detection of a reversal of the direction of current at the output of the direct voltage network (30) from a detection of the sign of the measured current, and, during operation of the electrical system (10) in generator mode, a detection of an exceeding of a short-circuit current threshold from a comparison of the measured current with a current threshold.

4. Method according to one of claims 1 to 3, in which the activation (430) of a control of the MOSFET gates (16) in an ideal diode mode comprises, for each MOSFET (16), a measurement of the voltage between the drain and the source of the MOSFET (16), a comparison of the voltage measured between the drain and the source of the MOSFET (16) to a zero voltage, and a conduction of the MOSFET (16) as soon as the voltage measured between the drain and the source of the MOSFET (16) is negative.

5. Method according to one of claims 1 to 3, in which the activation (430) of a control of the MOSFET gates (16) in an ideal diode mode comprises, for each MOSFET (16), a measurement of the current flowing through the MOSFET with a positive direction of the measurement going from the drain of the MOSFET towards the source, a comparison of the measured current to a zero or slightly negative current threshold, and a conduction of the MOSFET (16) as soon as the current is lower than this threshold.

6. An electrical system (10) for connection to a DC voltage network (30), the electrical system (10) comprising a rotating electrical machine (11) and a power converter (12) connected between the rotating electrical machine (11) and connection terminals (13) for connection to the DC voltage network (30), the power converter (12) comprising electrical arms (15) connected in parallel to each other, a filter capacitor (18) coupled in parallel to the electrical arms (15) and a filter inductor (19) connected in series between the filter capacitor (18) and one of said connection terminals (13), each electrical arm (15) comprising a series connection of at least two insulated gate field effect transistors, MOSFETs (16), and the power converter (12) further comprising a control circuit (40) for the gates of the MOSFETs comprising a protection module (42) configured to prohibit the simultaneous conduction of the MOSFETs (16) of the same arm (15), characterized in that it further comprises electrical protection means (14) against a short circuit of the DC voltage network (30) to which the electrical system (10) is intended to be connected, the electrical protection means (14) comprising: - a module (141) for detecting a short circuit on the DC voltage network (30), - a module (142) for deactivating the protection module (42) of the control circuit (40) of the gates of the MOSFETs controlled by said short circuit detection module (141), - at least one module (143) for controlling the gates of MOSFETs configured to control at least one MOSFET (16) in an ideal diode mode in which the MOSFET (16) conducts as soon as the voltage across its terminals is negative.

7. Electrical system (10) according to claim 6, wherein said rotating electrical machine (11) is a permanent magnet machine controlled in normal operation, without short circuit, by pulse width modulation to drive the motor or take power from the generator to supply the continuous electrical network (30).

8. Electrical system (10) according to one of claims 6 or 7, the gate control circuit (40) of the MOSFETs comprises a control input used in normal operation, without short circuit, and a reset input, the reset input being configured to deactivate the protection module (42) of the gate control circuit (40) upon receipt of a deactivation signal.

9. Electrical system (10) according to claim 8, comprising a first MOSFET gate control module for each MOSFET, said first control module comprising a multiplexer comprising a first input configured to receive a normal operation command from the MOSFET, a second input configured to receive an ideal diode mode operation command, a selection input, and an output configured to copy the first input as long as no signal has been received on the selection input and to copy the second input as an output of the multiplexer. when the select input receives a select signal, the select signal being received when the MOSFET gate driver circuit receives a reset command on its reset input.

10. Electrical system (10) according to one of claims 6 to 9, wherein the electrical protection means (14) further comprise means (145) for measuring the voltage at the terminals of the direct voltage network coupled to the connection terminals and means (146) for comparing the measured voltage to a voltage threshold below which the voltage drop corresponds to a short circuit on the direct voltage network, or means for measuring the current flowing on the direct voltage network coupled to one of said connection terminals and means for comparing the measured current to a current threshold.

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