Controllable switch

Abstract

The invention relates to a controllable switch (IC) comprising, between two terminals (BO1, BO2): - a first branch (B1) comprising a first module (E1) having a switch that can be controlled to close and open, and a second module (E2) connected in series with the first module, the second module being able to limit the current in the first branch or store energy; - a second branch (B2) comprising a third module (E3) having a switch that can be controlled to open and close, which is able to interrupt the current flowing in the second branch and maintain the voltage between the two terminals of the switch when it is in the open state; and - a control module (E5) which is able to control the first and third modules.

Description

[0001] CONTROLLABLE SWITCH

[0002] TECHNICAL FIELD

[0003] The present invention relates to a controllable power switch used in particular in aeronautical applications, or in other varied technical fields such as for example: automotive, defense, medical, nuclear.

[0004] The controllable switch according to the invention is an electrical distribution component which can be used in particular in HVDC distribution.

[0005] STATE OF THE PRIOR ART

[0006] The electrification of aircraft is a major trend, as is the increase in installed electrical power. As a result, electrical distribution system architectures are evolving. Originally operating at 28V DC, the main network voltage gradually increased to 115V three-phase AC at fixed frequency, then to variable frequency.

[0007] One of the objectives is the elimination of hydraulic networks for reasons of ease of maintenance and reduction of on-board mass (wiring, generator and other equipment). The increase in voltage levels in current aircraft (230V AC, + / -135V DC) for local networks follows this same trend. New 540V DC networks and up to 800V DC are now appearing in new electrical distribution or propulsion architectures.

[0008] Whatever the electrical distribution architectures considered, they systematically use distribution components allowing:

[0009] - the distribution of electrical energy to the aircraft loads,

[0010] - the protection of the lines which carry electrical energy to these loads.

[0011] These distribution components can, for example, be contactors, circuit breaker contactors or SSPC cards (Solid State Power Controller) depending on the applications and powers concerned.

[0012] Contactors and circuit-breaker contactors are both electromechanical components consisting of electromagnetic components (control coils generating a magnetic field) and mechanical parts (structural parts and moving parts ensuring electrical contact between the connection points of the contactor input and the output). The circuit-breaker contactor has an overcurrent protection function, called I2t, acting according to the energy / thermal selection principle, which controls the opening of the contactor in the event that the value of the integral of the current wave Jï 2.dt exceeds a predefined threshold.

[0013] A contactor consists of an assembly of an electric motor (similar to an electromagnet), moving and fixed parts to ensure the flow of current, and electronics to control the electric motor. The response time is quite slow (several tens of milliseconds). The breaking capacity is higher than with an SSPC card. The contactor and the circuit breaker contactor can incorporate simple to moderately complex control electronics that do not allow as many communication capabilities, configuration, and protection functions as an SSPC card.

[0014] SSPC cards use semiconductors such as JFET, MOSFET, IGBT, Bipolar or Thyristor, etc., which act as power switches. The technologies used can be of multiple types (Si, SiC, GaN, etc.).

[0015] The switching element of an SSPC card is made of power semiconductors. The switching element is controlled quickly and can be adjusted to meet the required requirements. The switching capacity is moderate. An SSPC card can incorporate protection, communication, control, and intelligent configuration functions because it incorporates a significant amount of electronics.

[0016] Furthermore, an electrical system includes various distribution devices, some of which are located close to the sources, and others are further away from them, close to the loads. The distribution devices close to the sources are called primary and must allow the distribution of high currents (for example, over fifty amps). The distribution devices close to the loads are called secondary and switch lower currents (for example, less than fifteen amps). Selectivity is essential in the management of the electrical system. A fault occurring on a distribution line must be interrupted by the nearest electrical distribution device. The cut-off is generally made at the level of the secondary distribution devices.It intervenes at the primary distribution level if the fault appeared nearby, on a primary distribution load or bar, or if the secondary distribution device failed to interrupt the fault close to a load.

[0017] Therefore, a primary distribution device must be designed to allow the fault current to pass for a time greater than that required for a secondary distribution device to interrupt the fault current.

[0018] Electrical distribution architectures using SSPC cards are being considered in HVDC zones, due to the functionalities offered by this type of component.

[0019] An HVDC SSPC board, although capable of quickly opening the electrical circuit in the event of a fault, is not always able to allow a very energetic current wave to pass through. This is why the ratio between the current value generating an immediate opening and the nominal current value is generally of the order of 1.5 to 2. This is due to heat dissipation and the operating temperature limit of the power components that make up the SSPC board. However, in the case of a fault appearing on a high voltage bus, the ratio between the fault current value and the nominal current value can easily exceed 10 or even 20.

[0020] The switching device of an HVDC SSPC board is also not able to dissipate a very large amount of energy when it opens. This dissipated energy may correspond to the energy stored in a source, in the wiring or in certain loads. Indeed, semiconductor components have a very limited breaking capacity compared to that of electromechanical switching devices. This breaking capacity constraint is illustrated by a limit pair "series inductance value on the line and maximum switched current", to be taken into consideration by the architect carrying out the definition of the electrical distribution.

[0021] The aim of this invention is therefore to propose a solution which makes it possible to overcome these difficulties. PRESENTATION OF THE INVENTION

[0022] The invention aims to solve the problems of the prior art by providing a controllable switch comprising between two terminals:

[0023] - a first branch comprising a first module comprising a switch controllable for closing and opening, and a second module connected in series with the first module, the second module being capable of limiting the current in the first branch or of storing energy,

[0024] - a second branch comprising a third module comprising a switch controllable for opening and closing, capable of interrupting the current flowing in the second branch and of maintaining the voltage between the two terminals of the switch when it is in the open state,

[0025] - a control module capable of controlling the first and third modules.

[0026] The controllable power switch combines two switching branches, thus enabling the optimization of performance in nominal operation, through the first branch, and also in fault conditions of a source or load, during switching, thanks to the second branch designed to improve the breaking capacity of the power switch in the event of a fault.

[0027] According to a preferred characteristic, the controllable switch comprises a measuring module capable of measuring the physical quantities of the first, second and third modules and of supplying the measured physical quantities to the control module.

[0028] According to a preferred characteristic, the third module of the second branch has an on-state resistance lower than the resistance of the first and second modules of the first branch.

[0029] According to a preferred characteristic, the third module comprises at least one MOSFET type power transistor.

[0030] According to a preferred characteristic, the third module comprises at least one SiC MOSFET type power transistor.

[0031] According to alternative preferred characteristics: - the first module integrates the second module and includes an IGBT type switch controlled so as to present a high impedance to limit the current passing through it in the event of a fault.

[0032] - the first module includes a controlled switch and the second module includes a dissipative element.

[0033] - the first module comprises a controlled switch and the second module comprises a passive circuit capable of storing and dissipating energy from an energy source.

[0034] The invention also relates to a method for controlling a controllable switch as previously presented, characterized in that it comprises steps of:

[0035] - monitoring of the current flowing through the controllable switch while it is closed,

[0036] - test to determine whether the current flowing through the controllable switch IC exceeds a predefined limit value,

[0037] - command to open the third module when the test result is positive,

[0038] - command to open the first module.

[0039] The invention also relates to a method for controlling a controllable switch as previously presented, characterized in that it comprises steps of:

[0040] - monitoring of the current flowing through the controllable switch while it is closed,

[0041] - test to determine whether the current flowing through the controllable switch IC exceeds a predefined limit value,

[0042] - command to open the third module when the test result is positive,

[0043] - command to close the third module,

[0044] - opening command for the first module,

[0045] - command to open the third module.

[0046] The invention also relates to a method for controlling a controllable switch as previously presented, characterized in that it comprises steps of:

[0047] - monitoring of the current flowing through the controllable switch while it is closed,

[0048] - test to determine whether the current flowing through the controllable switch exceeds a predefined limit value,

[0049] - command to close the first module when the test result is positive, - command to open the third module,

[0050] - test to determine whether the current flowing through the first module reaches a value lower than a predefined limit value,

[0051] - command to open the first module when the test result is positive.

[0052] The methods have advantages similar to those previously presented.

[0053] In a particular embodiment, the steps of the method according to the invention are implemented by computer program instructions.

[0054] Consequently, the invention also relates to a computer program comprising instructions adapted to the implementation of the steps of a method as described above. The invention also relates to an information medium readable by a computer, and comprising computer program instructions adapted to the implementation of the steps of a method as described above.

[0055] BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Other characteristics and advantages will appear on reading the following description of a preferred embodiment given by way of non-limiting example, described with reference to the figures in which:

[0057] [Fig. 1] illustrates a controllable switch according to one embodiment of the invention. [Fig. 2] illustrates the operation upon closing of the controllable switch according to one embodiment of the invention.

[0058] [Fig. 3] illustrates the operation upon opening of the controllable switch according to one embodiment of the invention.

[0059] [Fig. 4] illustrates a timing diagram of the current and the controls of the elements of the controllable switch according to the invention, in load fault mode, according to a first mode of operation.

[0060] [Fig. 5] illustrates a method of controlling the controllable switch, corresponding to the first mode of operation.

[0061] [Fig. 6] illustrates a timing diagram of the current and the controls of the elements of the controllable switch according to the invention, in load fault mode, according to a second operating mode. [Fig. 7] illustrates a method of controlling the controllable switch, corresponding to the second operating mode.

[0062] [Fig. 8] illustrates a branch of a controllable switch according to one embodiment of the invention.

[0063] [Fig. 9] illustrates a timing diagram of currents and voltages in elements of the controllable switch, and controls of the elements of the controllable switch, according to the embodiment of the invention of the previous figure.

[0064] [Fig. 10] illustrates a method of controlling the controllable switch, corresponding to the embodiment of the invention of the previous figure.

[0065] Identical, similar or equivalent parts of different figures bear the same numerical references so as to facilitate the transition from one figure to another.

[0066] The different parts represented in the figures are not necessarily on a uniform scale, to make the figures more readable.

[0067] The different possibilities (variants and embodiments) must be understood as not being mutually exclusive and can be combined with each other.

[0068] DETAILED PRESENTATION OF SPECIFIC EMBODIMENTS

[0069] According to a preferred embodiment shown in Figure 1, an embodiment of a controllable switch IC according to the invention comprises two terminals BO1 and BO2 between which two branches B1 and B2 are connected in parallel.

[0070] In use, a power source is connected upstream of the controllable switch IC and a load is connected downstream of the controllable switch IC. The power source and load are not shown.

[0071] The first branch B1 comprises a first module El comprising a first switch controllable for closing and opening. The first module El makes it possible to control the establishment of the current in the first branch B1 and is capable of maintaining the voltage across the terminals of the controllable switch when the latter is in the open state. The first module El has a low resistance in the on state (lower than the third module described below) and a high impedance in the open state. The first branch B1 comprises a second module E2 connected in series with the first module El. The second module E2 has the function of limiting the current in the first branch Bl. The second module E2 has a high resistance in the on state, compared to the first and third modules. The second module E2 may be a controlled or uncontrolled member. To simplify the description, the second module E2 is considered in the following as being uncontrolled.

[0072] According to a first embodiment, the second module E2 is integrated into the first module El. In this case, the first module El performs both the functions of the modules El and E2 presented previously, that is to say that it makes it possible to control the establishment of the current in the first branch Bl, that it is capable of maintaining the voltage at the terminals of the controllable switch when the latter is in the open state and that it limits the current in the first branch Bl. An example of a first module El which performs all these functions comprises an IGBT type switch, in particular a single IGBT type switch, controlled so as to present a high impedance to limit the current passing through it in the event of a fault.

[0073] To do this, we use the fact that the impedance presented by an insulated gate semiconductor component such as an IGBT can be controlled by the voltage value applied between the gate and emitter of the component. Above a threshold voltage value Vge_th applied between the gate and emitter of the component (th for threshold), the component allows a current to pass between emitter and collector. The higher the voltage value, while remaining below a maximum value causing the degradation of the component, the lower the voltage drop, and therefore the impedance presented by the component to the passage of current.

[0074] The control of the IGBT type switch involves the application of a control voltage value Vge, for example in the range of 12V to 15V, in nominal operating mode. The applied value depends on the desired current distribution between branch B1 and branch B2. In current limiting mode, and depending on the desired current value, the applied voltage value Vge will be lower, for example between 7V and 10V. To open the IGBT, a voltage value Vge below the threshold voltage Vge_th is applied between the gate and emitter of the component. According to another embodiment, the first module E1 comprises a controlled switch and the second module E2 comprises a dissipative element, for example a resistor with very high dissipation power.

[0075] According to yet another embodiment, branch B1 is designed to transfer energy to a capacitive reserve, instead of dissipating the energy. The mode of operation is preferably non-resonant, so as not to generate too high a voltage at the terminals of branches B1 and B2 which would risk damaging component E3.

[0076] An example according to this embodiment is shown in Figure 8, which illustrates the branch Bl, in the case of a monodirectional current assembly and use with a continuous source.

[0077] Branch Bl includes the first module El, comprising an IGBT and a diode Dl.

[0078] Branch Bl includes the second module E2, in series with the first module El.

[0079] The second module E2 is a passive circuit comprising an inductor L1, a capacitor C2 and a resistor RI connected in series between terminals of the second module E2.

[0080] The second module E2 also includes a resistor R2 connected in parallel with the resistor RI and the capacitor C2.

[0081] The second module E2 still includes a capacitor Cl connected in series with a transil diode Ul, these two components being connected in parallel with the resistor RI and the capacitor C2.

[0082] The second module E2 finally includes a resistor R3 connected in parallel with the capacitor Cl.

[0083] The operation of this embodiment will be explained later.

[0084] According to another embodiment, the second module E2 is integrated into the first module El. In this case, the first module El performs both the functions of the modules El and E2 presented previously. In other words, the branch Bl only comprises a controllable switch El having the capacity to limit the current, by desaturation, for example. In this embodiment, the switch El can be an IGBT for example. In all cases, the first branch B1 performs a limitation of the current passing through it, either thanks to the second module E2 when it is actually present, or thanks to the first module El, when the latter integrates the module E2 and performs both the functions of the module El and the module E2.

[0085] The second branch B2 comprises a third module E3 comprising a switch controllable for opening and closing, capable of interrupting the current flowing in the second branch and of maintaining the voltage between the two terminals of the switch when it is in the open state.

[0086] The third module E3 has a much lower on-state resistance than the resistance of the modules El and E2 of the first branch Bl.

[0087] The third module E3 is therefore crossed by the majority of a nominal current passing through the controllable switch IC, except in the event of a fault.

[0088] The third E3 module can advantageously include one or more controllable power switches of the MOSFET type or even of the silicon carbide MOSFET type, known as SiC MOSFET, so as to obtain a very low on-state resistance.

[0089] The controllable switch IC includes a module E4 which includes measuring sensors for measuring the physical quantities required to control modules El to E3.

[0090] The measuring sensors are used to measure currents and voltages useful for controlling the switch. They are standard in themselves and are not described in detail.

[0091] The controllable switch IC comprises a control module E5 connected to the modules El to E4 and capable of controlling the first and third modules El and E3, on the basis of the values ​​measured by the module E4.

[0092] The closing operation of the controllable switch IC according to an embodiment of the invention is now described with reference to Figure 2. The controllable switch IC according to this embodiment has the ability to limit the current flowing through it.

[0093] Figure 2 shows states S0 to S2 of the controllable switch IC and the transitions from one state to the next. To simplify the figure, modules E1 and E3 are represented by perfect switches having an open position in the rest state.

[0094] The initial state S0 is the rest state, in which the switches E1 and E3 are open. The second module E2 is conducting. The controllable switch IC is open.

[0095] When the closing of the controllable switch IC is requested by the control module E5, the following closing sequence is carried out.

[0096] Module E5 controls the closing of switch El, which allows the transition from state S0 to state SI. Switch El then establishes the current in branch Bl, since the second module E2 is already conducting. Because switch El is controlled upon closing, the voltage across its terminals and the time of application of the constraint are also controlled.

[0097] Closing the switch El makes it possible to limit the value of the current on closing, due to the presence of the second module E2, in particular if the switch El establishes a short-circuit current between the power source connected upstream of the controllable switch IC and the load connected downstream of the controllable switch IC.

[0098] In state SI, switch El is closed, the second module E2 is conducting and switch E3 is open.

[0099] Module E5 controls the closing of switch E3, which allows the transition from state SI to state S2. Switch E3 establishes the current in branch B2. Because switch E3 is controlled upon closing, the voltage across its terminals and the time of application of the constraint are also controlled. Switch E3 closes at zero current and at very low voltage, since the voltage taken across the terminals of the controllable switch IC, therefore of modules El and E2, is only a few volts at most.

[0100] Closing switch E3 causes almost all of the current from controllable switch IC to flow into branch B2, because the total series resistance of all modules El and E2 is much greater than that of switch E3.

[0101] In state S2, switch El is closed, the second module E2 is conducting and switch E3 is closed. The controllable switch IC is closed.

[0102] The operation upon opening of the controllable switch IC according to an embodiment of the invention is now described with reference to Figure 3. Figure 3 represents the states S0 to S2 and the transitions from one state to the next of the controllable switch IC.

[0103] As in the previous figure, modules El and E3 are represented by perfect switches having an open position in the rest state.

[0104] The initial state is state S2, in which switches E1 and E3 are closed. The second module E2 is conducting. The controllable switch IC is closed.

[0105] When the opening of the controllable switch IC is requested by the control module E5, the following opening sequence is carried out.

[0106] Module E5 controls the opening of switch E3, which allows the transition from state S2 to state SI. Switch E3 is opened under moderate voltage, since modules El and E2 allow current to flow through controllable switch IC.

[0107] In state SI, switch El is closed, the second module E2 is conducting and switch E3 is open. All current flows through branch Bl.

[0108] Module E5 controls the opening of switch El, which allows the transition from state SI to state S0. Once switches El and E3 are open, isolation is ensured between the upstream and downstream parts of the controllable switch IC.

[0109] Figure 4 shows a first mode of control of the controllable switch IC in the event of a fault. The upper part of Figure 4 shows a timing diagram of the current flowing through the controllable switch IC and the lower part of Figure 4 shows the controls of the modules E1 and E3 of the controllable switch IC.

[0110] Initially, the controllable switch IC is closed, i.e., modules E1 and E3 are closed. We consider a phase PI between times t0 and t1 in which a current flows through the controllable switch IC and is consumed by the load. Phase PI is an operating phase of the controllable switch IC at nominal current. We assume that a short-circuit type fault appears at time t1. When the fault appears, the current increases rapidly during a phase P2. The current slope is defined by the characteristics of the energy source and the connecting cables between the source and the fault location. Phase P2 is a current rise phase during the short circuit. Almost all of the current flowing through the controllable switch IC passes through branch B2, therefore through the third module E3, as explained above.As soon as the fault current reaches a predefined limit value at a time t2, the E5 module commands the opening of the third E3 module. There is no discontinuity in the current which passes successively from branch B2 to branch Bl. During a P3 phase, the second E2 module limits the current flowing through it to a value determined by construction or by adjustment according to the technology adopted. Phase P3 is a current limitation phase during the short circuit.

[0111] The opening of the first module El is then controlled by the module E5, at a time t3 which can be determined on the basis of an energy activation criterion (12) or on the passage of the current value below a predetermined threshold. A phase P4 follows during which the first module El dissipates the energy and the current passing through the controllable switch IC decreases, until it becomes zero at a time t4 depending on the control mode of the first module El. Phase P4 is a phase of decrease of the current at the opening of the controllable switch IC.

[0112] Figure 5 represents a method for controlling the controllable switch IC, in the event of a fault, corresponding to Figure 4. The control method comprises steps 1 to 4 implemented in the control module E5.

[0113] Step 1 is a monitoring of the physical quantities of the controllable switch IC measured by the module E4, in particular the current which passes through the controllable switch IC while it is closed, that is to say that the modules El and E3 are closed.

[0114] The next step 2 is a test to determine whether the current through the controllable switch IC exceeds a predefined limit value.

[0115] When the test result is positive, step 2 is followed by step 3 in which the control module E5 commands the opening of the third module E3.

[0116] The next step 4 is an opening command of the first module El by the control module E5.

[0117] Figure 6 represents a second control mode of the controllable switch IC in the event of a fault. The upper part of Figure 6 represents a timing diagram of the current flowing through the controllable switch IC and the lower part of Figure 4 represents the controls of the modules E1 and E3 of the controllable switch IC. Initially, the controllable switch IC is closed, i.e., the modules E1 and E3 are closed. We consider a phase PI' between times t0' and tl' in which a current flows through the controllable switch IC and is consumed by the load. Phase PI' is an operating phase of the controllable switch IC at nominal current. We assume that a short-circuit type fault appears at time tl'. When the fault appears, the current increases rapidly during a phase P2'. The current slope is defined by the characteristics of the energy source and the connecting cables between the source and the fault location.Phase P2' is a current rise phase during the short circuit. Almost all of the current flowing through the controllable switch IC passes through branch B2, therefore through the third module E3, as explained above.

[0118] As soon as the fault current reaches a predefined limit value at time t2', the E5 module commands the opening of the third E3 module. There is no discontinuity in the current which passes successively from branch B2 to branch Bl. During a P3' phase, the second E2 module limits the current flowing through it to a value determined by construction or by adjustment according to the technology adopted. Phase P3' is a current limitation phase during the short circuit.

[0119] It is assumed that the first module E1 has a breaking capacity but that it is limited. The closing of the third module E3 is then controlled by the module E5, at time t3', before the physical limits of the second module E2 are reached.

[0120] This results in an increase in the current flowing through the controllable switch IC and the transfer of almost all of the current from branch B1 to branch B2, during a phase P4'. During this phase, the module E5 controls the opening of the first module E1. Then at a time t4', the module E5 controls the opening of the third module E3. Phase P4' is a phase of current increase during the short-circuit. This is followed by a phase P5' during which the current flowing through the controllable switch IC decreases, until it becomes zero at a time t5' depending on the control mode of the third module E3. Phase P5' is a phase of current decrease when the controllable switch IC opens. Figure 7 represents a method for controlling the controllable switch IC, in the event of a fault, corresponding to Figure 6. The control method comprises steps 1' to 6' implemented in the control module E5.

[0121] Step 1 is a monitoring of the physical quantities of the controllable switch IC measured by the module E4, in particular the current which passes through the controllable switch IC while it is closed, that is to say that the modules E1 and E3 are closed.

[0122] The next step 2' is a test to determine whether the current through the controllable switch IC exceeds a predefined limit value.

[0123] When the test result is positive, step 2' is followed by step 3' at which module E5 commands the opening of the third module E3.

[0124] The next step 4' is a command to close the third module E3 by the module E5.

[0125] The next step 5' is a command to open the first module El by module E5.

[0126] The next step 6' is a command to open the third module E3 by the module E5.

[0127] Figure 9 represents a control mode of the controllable switch IC shown in Figure 8, in the event of a fault. Figure 9 represents from top to bottom:

[0128] - a timing diagram of the current flowing through capacitor Cl and the voltage across capacitor Cl,

[0129] - a timing diagram of the current flowing through capacitor C2 and the voltage across capacitor C2,

[0130] - a timing diagram of the current flowing through the third module E3 and the voltage across the terminals of the third module E3,

[0131] -the commands of the El and E3 modules of the controllable switch IC.

[0132] In the initial state, modules El and E3 are open.

[0133] The closing of the controllable switch IC is requested by the control module E5, the following closing sequence is carried out.

[0134] Module E5 controls the closing of the third module E3 at a time t0”. The third module E3 establishes the current in branch B2. Because the third module E3 is controlled at closing, the voltage across its terminals and the time of application of the constraint are also controlled. The voltage source then supplies the current required for the load supplied by switch E3.

[0135] It is assumed that a short-circuit fault occurs downstream of the third module E3 at time t1". The current in the third module E3 increases rapidly. The current gradient is defined by the characteristics of the energy source and the connecting cables between the source and the fault location. As soon as the fault current reaches a predefined limit value at time t2", the module E5 commands the closing of the first module E1. The module E5 commands the opening of the third module E3 at time t3", very shortly after time t2".

[0136] Opening the third module E3 causes the current in branch B2 to decrease. Branch B1 carries all the source current.

[0137] Inductance L1 limits the current slope when the first module El closes. It is useful when using the controlled switch IC with a capacitive source (little series inductance).

[0138] The current increases in capacitor C2, limited by resistor RI. The voltage across capacitor C2 also increases. If a threshold voltage value imposed by the trigger voltage of transil diode Ul is exceeded, the source current charges capacitor Cl. The second module E2 stores the energy coming from the source.

[0139] The capacitance value of capacitor C2 is chosen so that the current growth in branch B1 is rapid. The capacitance value of capacitor C2 must not be too large, otherwise the source current would continue to flow in branch B2. On the other hand, the capacitance value of capacitor Cl is significantly larger than the capacitance value of capacitor C2 and remains sized by the permissible overvoltage and the estimate of the line inductance between source and controllable switch IC.

[0140] Once the energy from the line inductance is transferred to capacitors C1 and C2, the current in the first module E1 is zero. When the current through the first module E1 reaches a value lower than a predefined limit value, module E5 commands the opening of the first module E1 at a time t4''. The energy stored in capacitors C1 and C2 is dissipated in resistors R3 and R2, respectively.

[0141] Figure 10 shows a method for controlling the controllable switch IC, in the event of a fault, corresponding to Figure 9. The control method comprises steps 1” to 6” implemented in the control module E5.

[0142] Step 1” is a monitoring of the physical quantities of the controllable switch IC measured by the module E4, in particular the current which passes through the controllable switch IC while it is closed, i.e. the third module E3 is closed.

[0143] The next step 2" is a test to determine whether the current through the controllable switch IC exceeds a predefined limit value.

[0144] When the test result is positive, step 2" is followed by step 3" in which the control module E5 commands the closure of the first module El.

[0145] The next step 4'' is a command to open the third module E3 by the control module E5.

[0146] The next step 5" is a test to determine whether the current flowing through the first El module reaches a value below a predefined limit value.

[0147] When the test result is positive, step 5'' is followed by step 6'' at which the control module E5 commands the opening of the first module El.

[0148] The advantages of the controllable switch IC according to the invention are as follows:

[0149] The third E3 module can be sized to the nominal current value of the controllable switch IC, but is not necessarily designed to interrupt all the energy stored on the distribution line at the highest current point. This makes it possible to limit the number of components to be used, thus resulting in a proven cost saving if, for example, very expensive SiC MOSFET chips are used, or to select semiconductor chips by favoring on-state resistance rather than high current and high voltage resistance.

[0150] The closing sequence of the controllable switch IC by the first module El first makes it possible to limit the value of the establishment current by the presence of a higher total impedance value in branch B1 by all modules El and E2. This constitutes the equivalent of a precharge function which limits the inrush current. During the closing sequence of the controllable switch IC, the third module

[0151] E3 is closed at zero current and low voltage, since the voltage across all modules El and E2 is low compared to the source voltage.

Claims

CLAIMS 1. Controllable switch (IC) comprising between two terminals (BO1, BO2): - a first branch (Bl) comprising a first module (El) comprising a switch controllable for closing and opening, and a second module (E2) connected in series with the first module, the second module being capable of limiting the current in the first branch or of storing energy, - a second branch (B2) comprising a third module (E3) comprising a switch controllable for opening and closing, capable of interrupting the current flowing in the second branch and of maintaining the voltage between the two terminals of the switch when it is in the open state, - a control module (E5) capable of controlling the first and third modules.

2. Controllable switch according to claim 1, in which, the second module being capable of storing energy, the first module (El) comprises a controlled switch and the second module (E2) comprises a passive circuit capable of storing and dissipating energy coming from an energy source.

3. Controllable switch according to claim 1, in which the first module (El) integrates the second module (E2) and comprises an IGBT type switch controlled so as to present a high impedance to limit the current passing through it in the event of a fault.

4. Controllable switch according to claim 1, in which, the second module being capable of limiting the current in the first branch, the first module (El) comprises a controlled switch and the second module (E2) comprises a dissipative element.

5. Controllable switch according to any one of claims 1 to 4, comprising a measurement module (E4) capable of measuring the physical quantities of the first, second and third modules (El, E2, E3) and of supplying the measured physical quantities to the control module (E5).

6. Controllable switch according to any one of claims 1 to 5, in which the third module (E3) of the second branch has a resistance in the on state lower than the resistance of the first and second modules of the first branch.

7. Controllable switch according to any one of claims 1 to 6, in which the third module (E3) comprises at least one MOSFET type power transistor.

8. Controllable switch according to any one of claims 1 to 6, in which the third module (E3) comprises at least one power transistor of the MOSFET SIC type.

9. Method for controlling a controllable switch (IC) according to any one of claims 1 and 3 to 7, characterized in that it comprises steps of: - monitoring (1) of the current flowing through the controllable switch while it is closed, - test (2) to determine whether the current flowing through the controllable switch IC exceeds a predefined limit value, - command (3) to open the third module (3) when the test result is positive, - command (4) to open the first module (1).

10. Method for controlling a controllable switch (IC) according to any one of claims 1 and 3 to 7, characterized in that it comprises steps of: - monitoring (1') of the current flowing through the controllable switch while it is closed, - test (2') to determine whether the current flowing through the controllable switch IC exceeds a predefined limit value, - command (3') to open the third module (E3) when the test result is positive, - command (4') to close the third module (E3), - command (5') to open the first module (El), - command (6) to open the third module (E3).

11. Method for controlling a controllable switch (IC) according to claim 2, characterized in that it comprises steps of: - monitoring (1") of the current flowing through the controllable switch while it is closed, - test (2") to determine whether the current flowing through the controllable switch (IC) exceeds a predefined limit value, - command (3") to close the first module (El) when the test result is positive, - command (4") to open the third module (E3), - test (5'') to determine whether the current flowing through the first module (El) reaches a value lower than a predefined limit value, - command (6'') to open the first module (El) when the test result is positive.

12. Computer program comprising instructions for executing the steps of the method according to any one of claims 9 to 11 when said program is executed by a computer.

13. Computer-readable recording medium on which is recorded a computer program comprising instructions for carrying out the steps of the method according to any one of claims 9 to 11.

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