Device for controlling precharging of a storage capacity and fault detection in a direct current circuit

Abstract

Device for controlling precharging of a storage capacity and fault detection in a direct current circuit The present description relates to a device for controlling precharging of a storage capacity and fault detection in a direct current circuit which comprises the storage capacity, at least one direct voltage source and at least one first precharging switch coupled to an electrode of the storage capacity, the device comprising at least: - a pulse transformer provided with a primary and at least one first and one second secondaries; - a circuit for controlling precharging of the storage capacity, coupled to the primary of the pulse transformer;wherein the first secondary of the pulse transformer has a first terminal configured to be coupled to a control input of the first precharge switch, and wherein the second secondary of the pulse transformer is configured to be coupled in parallel with the storage capacitor. Figure for abstract: Fig. 1;

Description

Title of the invention: Device for controlling the precharging of a storage capacity and for detecting faults in a direct current circuit Technical field

[0001] The present description relates generally to the field of direct current electric circuits. Prior art

[0002] In a direct current electrical circuit, a bus comprising at least two electrically conductive elements is coupled on one side to a direct voltage source corresponding for example to a battery or to the output of a DC / DC (or direct - direct) or AC / DC (or alternating - direct) converter, and on the other to circuit components including capacitive elements which can be likened together to a storage capacitor, or "bulk capacitor" in English. This storage capacitor is coupled in parallel with the direct voltage source by the conductive elements of the bus and by at least one switch making it possible to couple or decouple the direct voltage source with respect to the bus.

[0003] When the switch is closed to couple the bus to the DC voltage source, a large inrush current flows between the DC voltage source and the storage capacitor. To prevent this inrush current from occurring, the storage capacitor may be precharged by circulating a precharge current through the storage capacitor before the switch is closed. This precharge phase is implemented for a sufficient duration to obtain the desired precharge voltage across the storage capacitor.

[0004] However, during this storage capacity pre-charging phase, if a fault is present on the bus, such as for example a short circuit or a significant current leak, a very high current can flow in the bus and damage the other elements of the circuit coupled to the bus.

[0005] When a thyristor is used as a switch to couple the DC voltage source to the bus during precharging of the storage capacity, in the event of a fault present on the circuit, it is not possible to block this thyristor because the current flowing through it is then very high. Blocking the thyristor to stop the flow of this high current requires the use of an additional circuit dedicated to this function.

[0006] When an electromechanical relay is used as a switch to couple the DC voltage source to the bus when precharging the storage capacity, it is possible to detect a short circuit of the storage capacity. However, this detection is only possible when the relay is closed, which leaves, before this detection, a certain period during which the current flowing can damage elements of the circuit. In addition, the opening time of an electromechanical relay is long and increases over time. Summary of the invention

[0007] There is a need to propose a solution making it possible to detect the presence or absence of a fault in a direct current circuit before carrying out a precharge of a storage capacity of the circuit in the absence of such a fault.

[0008] An embodiment overcomes all or part of the drawbacks of the known solutions and proposes a device for controlling the precharging of a storage capacitor and for detecting a fault in a direct current circuit which comprises the storage capacitor, at least one direct voltage source and at least one first precharging switch coupled to an electrode of the storage capacitor, the device comprising at least:

[0009] - a pulse transformer having a primary and at least one first and one second secondary;

[0010] - a storage capacity precharge control circuit, coupled to the primary of the pulse transformer;

[0011] wherein the first secondary of the pulse transformer has a first terminal configured to be coupled to a control input of the first precharge switch, and wherein the second secondary of the pulse transformer is configured to be coupled in parallel with the storage capacitor.

[0012] In a particular embodiment, the device further comprises at least a first energy storage capacitor coupled in parallel with the first secondary of the pulse transformer.

[0013] In a particular embodiment, the device further comprises at least one first voltage rectifier diode whose anode is coupled to the first terminal of the first secondary of the pulse transformer, and / or at least one first current limiting electrical resistor whose electrode is configured to be coupled to the control input of the first precharge switch.

[0014] In a particular embodiment, the device further comprises at least one second Zener diode whose cathode is coupled to the cathode of the first voltage rectifier diode and whose anode is configured to be coupled to the control input of the first precharge switch.

[0015] In a particular embodiment, the device further comprises at least one second protection diode coupled in series to the second secondary of the pulse transformer.

[0016] In a particular embodiment, the storage capacity precharge control circuit comprises at least:

[0017] - a third diode whose cathode is coupled to a first terminal of the primary of the pulse transformer;

[0018] - a first Zener diode whose anode is coupled to the anode of the third diode and whose cathode is coupled to a second terminal of the primary of the pulse transformer;

[0019] - a control switch coupled to the second terminal of the primary of the trans pulse trainer.

[0020] In a particular embodiment, a second terminal of the first secondary of the pulse transformer is coupled to one of the terminals of the second secondary of the pulse transformer.

[0021] In a particular embodiment, the pulse transformer comprises at least a third secondary whose terminals are configured to be coupled to a voltage measuring device or to a control input of a second precharge switch.

[0022] A direct current circuit is also provided, comprising at least:

[0023] - a direct voltage source;

[0024] - a bus comprising at least two conductive elements each coupled to one of the terminals of the direct voltage source;

[0025] - a capacitive element forming a storage capacity, each of the electrodes of which is coupled to one of the two conductive elements of the bus;

[0026] - a first precharge switch coupled to an electrode of the capacitance of storage ;

[0027] - a storage capacity precharge control and detection device fault in the direct current circuit according to a particular embodiment.

[0028] According to a particular embodiment, the direct voltage source comprises at least one battery.

[0029] According to a particular embodiment, the first precharge switch comprises at least a first thyristor and the control input of the first precharge switch corresponds to the trigger of the first thyristor, and the circuit further comprises at least:

[0030] - a second current-limiting electrical resistor coupled in series to the first thyristor;

[0031] - first and second cut-off switches each coupled between one of the terminals of the DC voltage source and one of the electrodes of the capacitor storage, at least one of the first and second cut-off switches comprising a relay.

[0032] According to a particular embodiment, one of the first and second cut-off switches is coupled in parallel with the first thyristor and the second current-limiting electrical resistor.

[0033] According to a particular embodiment:

[0034] - the direct voltage source comprises an AC / DC voltage converter of the type pole totem comprising at least two conversion transistors and at least two conversion thyristors, the triggers of which are each coupled to a third current-limiting electrical resistor and an optocoupler coupled in series with each other and forming first and second precharge switches;

[0035] - the pulse transformer of the device comprises at least a third se secondary;

[0036] - the first terminal of the first secondary of the pulse transformer of the device is coupled to an input electrode of one of the optocouplers; and

[0037] - a first terminal of the third secondary of the pulse transformer of the device is coupled to an input electrode of the other of the optocouplers.

[0038] According to a particular embodiment:

[0039] - the direct voltage source comprises an AC / DC voltage converter of the type Mixed bridge PFC boost comprising at least two conversion diodes and at least two conversion thyristors, or at least four conversion thyristors, the gates of which are each coupled to a third current-limiting electrical resistor and an optocoupler coupled in series with each other and forming first and second precharge switches; and

[0040] - the first terminal of the first secondary of the pulse transformer of the device is coupled to an input electrode of each of the optocouplers.

[0041] According to a particular embodiment: - the DC voltage source includes a Boost PFC type AC / DC voltage converter with diode bridge; - the first precharge switch comprises at least a first thyristor, a third current-limiting electrical resistor and an optocoupler coupled in series with each other.

[0042] There is also provided a method for controlling precharging of a storage capacitor and for detecting a fault in a direct current circuit which comprises the storage capacitor, at least one direct current voltage source and at least one first precharging switch coupled to an electrode of the storage capacitor. This method uses a pulse transformer having a primary and at least a first and a second secondary, as well as a control circuit of precharge of the storage capacitor which is coupled to the primary of the pulse transformer. In this method, the first secondary has a first terminal coupled to a control input of the first precharge switch, and the second secondary is coupled in parallel with the storage capacitor.

[0043] In a particular embodiment, the method comprises sending a control signal, by the storage capacitor precharge control circuit, to the primary of the pulse transformer. In the absence of a fault in the direct current circuit, the method comprises generating voltages across the terminals of the first and second secondaries, and sending a current to the control input of the first precharge switch which triggers the precharge of the storage capacitor. In the presence of a fault in the direct current circuit, the method comprises maintaining a zero or very low voltage across the terminals of the first and second secondaries, and maintaining the first precharge switch in the off state preventing the precharge of the storage capacitor. Brief description of the drawings

[0044] These characteristics and advantages, as well as others, will be explained in detail in the following description of particular embodiments given without limitation in relation to the attached figures among which:

[0045] - [Fig.l] schematically represents an example of an embodiment of a device for precharge control of a storage capacity and fault detection in a direct current circuit;

[0046] - [Fig.2] schematically represents a precharge control device of a fault storage and detection capacity in a direct current circuit according to a first embodiment;

[0047] - [Fig.3] represents a schematic timing diagram of signals obtained within the device for controlling precharging of a storage capacity and detecting a fault in a direct current circuit according to the first embodiment, in the absence of a fault in the circuit;

[0048] - [Fig.4] represents a schematic timing diagram of signals obtained within the device for controlling precharging of a storage capacity and detecting a fault in a direct current circuit according to the first embodiment, in the presence of a fault in the circuit;

[0049] - [Fig.5] schematically represents a preload control device of a fault storage and detection capacity in a direct current circuit according to a first variant of the first embodiment;

[0050] - [Fig.6] schematically represents a preload control device of a storage and fault detection capacity in a direct current circuit according to a second variant of the first embodiment;

[0051] - [Fig.7] schematically represents a preload control device of a fault storage and detection capacity in a direct current circuit according to a second embodiment;

[0052] - [Fig.8] schematically represents a preload control device of a fault storage and detection capacity in a direct current circuit according to a third embodiment; and

[0053] - [Fig.9] schematically represents a preload control device of a fault storage and detection capacity in a direct current circuit according to a fourth embodiment. Description of the embodiments

[0054] The same elements have been designated by the same references in the different figures. In particular, the structural and / or functional elements common to the different embodiments may have the same references and may have identical structural, dimensional and / or material properties.

[0055] For the sake of clarity, only the steps and elements useful for understanding the described embodiments and examples have been shown and are detailed. In particular, various elements (voltage source, bus, switches, control circuit, transformer, etc.) of the device for controlling the precharging of a storage capacitor and for detecting faults in a direct current circuit are not detailed. Those skilled in the art will be able to produce these elements in detail from the functional description given here.

[0056] Unless otherwise specified, when referring to two elements connected to each other, this means directly connected without intermediate elements other than conductors, and when referring to two elements connected (in English "coupled") to each other, this means that these two elements can be connected or be connected by means of one or more other elements.

[0057] Unless otherwise specified, the term “conductor” is used to designate electrical conduction.

[0058] Throughout the document, the term "fault" used in connection with the direct current circuit designates an electrical fault present in the circuit, for example a short circuit of the storage capacity or a significant current leak.

[0059] Unless otherwise specified, the expressions "about", "approximately", "substantially", and "of the order of" mean to within 10%, preferably to within 5%.

[0060] An exemplary embodiment of a device 100 for controlling the precharging of a storage capacity 1002 and for detecting a fault in a direct current circuit 1000 in which the storage capacity 1002 is located is described below in connection with [Fig.l].

[0061] The circuit 1000 comprises at least one direct voltage source 1004 comprising for example one or more batteries and / or at least one DC / DC or AC / DC converter. Other types of direct voltage sources may however be included in the circuit 1000.

[0062] The circuit 1000 further comprises a bus intended for the circulation of a direct current in the circuit 1000 and comprising at least two conductive elements 1006 each coupled to one of the terminals of the source 1004. In the exemplary embodiment described, the source 1004 is intended to apply a direct electrical voltage to these conductive elements 1006 and to deliver a direct current circulating in the conductive elements 1006 of the bus.

[0063] The circuit 1000 further comprises other electrical components coupled to the bus and forming one or more capacitive electrical elements which are, together, assimilated to the storage capacitor 1002. Each of the electrodes of the storage capacitor 1002 is coupled to one of the two conductive elements 1006 of the bus of the circuit 1000.

[0064] The circuit 1000 further comprises at least one precharge switch 1008 coupled to one of the electrodes of the storage capacitor 1002. In the example of [Fig.l], the precharge switch 1008 is included in the source 1004. Alternatively, the precharge switch 1008 may be a separate element from the source 1004. The precharge switch 1008 may be coupled between a first terminal of the source 1004 and one of the electrodes of the storage capacitor 1002.

[0065] The circuit 1000 further comprises the device 100 for controlling the precharging of the storage capacity 1002 and for detecting faults in the circuit 1000.

[0066] The device 100 comprises at least one pulse transformer 102 provided with a primary 104 and at least a first secondary 106 and a second secondary 108, the primary 104 being magnetically coupled to the first and second secondaries 106, 108. The first and second secondaries 106, 108 may or may not be similar to each other, in terms of number of turns. The electrical characteristics of the transformer 102 may be chosen in particular as a function of the voltage and current levels to which the elements of the transformer 102 are intended to be subjected.

[0067] The device 100 further comprises a circuit 110 for controlling the precharging of the storage capacitor 1002, which is coupled to the primary 104. In the exemplary embodiment described, the circuit 110 is intended to apply a voltage in the form of pulses to the terminals of the primary 104 during a precharging of the storage capacitor 1002.

[0068] The first secondary 106 comprises a first terminal 112 coupled to a control input of the precharge switch 1008. In the example of [Fig.l], the first terminal 112 of the first secondary 106 is coupled to the control input of the precharge switch 1008 via a voltage rectifier diode 114 having its anode coupled to the first terminal 112 and its cathode coupled to the control input of the precharge switch 1008.

[0069] In the described embodiment, the device 100 further comprises an energy storage capacitor 116 coupled in parallel with the first secondary 106 and intended to provide a power supply for controlling the precharge switch 1008. In the example of [Fig. 1], the first terminal 112 of the first secondary 106 is coupled to one of the electrodes of the energy storage capacitor 116 via the voltage rectifier diode 114, the energy storage capacitor 116 being here coupled in parallel with the assembly formed by the first secondary 106 and the voltage rectifier diode 114. In the example of [Fig. 1], the cathode of the voltage rectifier diode 114 is coupled to one of the electrodes of the energy storage capacitor 116 and the anode of the voltage rectifier diode 114 is coupled to the first terminal 112 of the first secondary 106.Taking into account the voltage variations across the terminals of the first secondary 106, the voltage rectifier diode 114 makes it possible to charge the energy storage capacity 116 with a continuous and constant voltage when the voltage across the terminals of the first secondary 106 is positive.

[0070] The second secondary 108 is coupled in parallel with the storage capacitor 1002. In the example of [Fig.l], the device 100 further comprises a protection diode 118 coupled in series with the second secondary 108 and preventing the storage capacitor 1002 from discharging through the second secondary 108 during a precharge of the storage capacitor 1002, while allowing current to flow between the storage capacitor 1002 and the second secondary 108 during the fault presence verification phase. In a particular configuration corresponding to that shown in [Fig.l], the cathode of the protection diode 118 is coupled to one of the terminals of the second secondary 108 and the anode of the protection diode 118 is coupled to one of the electrodes of the storage capacitor 1002. In the example of [Fig.l], the storage capacitor 1002 is coupled in parallel with the assembly formed by the second secondary 108 and the protection diode 118..

[0071] In this circuit 1000 comprising the device 100, when the storage capacity 1002 is intended to be precharged, for example before a connection of the source 102 to the bus, the circuit 110 controls the transformer 102 such that a voltage in the form of non-zero pulses is applied to the terminals of the primary 104. In the absence of a fault, in particular in the absence of a short circuit at the terminals of the storage capacity 1002, a first voltage in the form of non-zero pulses is generated at the terminals of the first secondary 106 and a second voltage in the form of non-zero pulses is generated at the terminals of the second secondary 108. The second voltage at the terminals of the second secondary 108 charges the storage capacity 1002, for example a few volts, and at the same time, the first voltage present at the terminals of the first secondary 106 generates a current flowing through the energy storage capacity 116 and thus increasing the potential difference at the terminals of the energy storage capacity 116. This potential difference at the terminals of the energy storage capacity 116 causes a control current to be sent to the control input of the precharge switch 1008, which then triggers the precharge of the storage capacity 1002 when the precharge switch 1008 turns on.

[0072] On the other hand, in the presence of a fault such as a short circuit at the terminals of the storage capacitor 1002, the voltage at the terminals of the second secondary 108 remains zero notwithstanding the voltage applied by the circuit 110 to the primary 104. The voltage at the terminals of the first secondary 106 therefore also remains zero.Thus, no current flows to charge the energy storage capacity 116, and therefore no control current is sent to the control input of the precharge switch 1008. The precharge of the storage capacity 1002 is therefore not triggered because the precharge switch 1008 remains in the blocked state.

[0073] Thus, the transformer 102 simultaneously fulfills two functions: the first secondary 106 is used to control the conduction state of the precharge switch 1008 depending on the presence or absence of a fault in the circuit 1000, and the second secondary 108 is used to detect the presence or absence of a fault in the circuit 1000.

[0074] An example of the device 100 and the circuit 1000 according to a first embodiment is described below in connection with [Fig. 2]. In this first embodiment, the circuit 1000 may be part of or form a vehicle battery monitoring system.

[0075] In the first embodiment, the source 1004 comprises one or more batteries delivering a direct voltage VBat. For example, the battery or batteries of the source 1004 may correspond to that(they) of an electric vehicle, the voltage delivered to the terminals of the source 1004 being able to be equal to approximately 400 V or 800 V or another value.

[0076] In the example of [Fig.2], the circuit 110 comprises at least:

[0077] - a diode 120 whose cathode is coupled to a first terminal of the primary 104;

[0078] - a Zener diode 122 whose anode is coupled to the anode of the diode 120 and whose cathode is coupled to a second terminal of the primary 104;

[0079] - a control switch 124 configured to control the pulses of voltage applied to the terminals of the primary 104.

[0080] The diodes 120, 122 form a demagnetization circuit for the transformer 102. In a first phase, the control switch 124 is closed and a current then flows in the primary 104. When the primary 104 is blocked via the opening of the control switch 124, the energy stored in the transformer 102 must be evacuated. An overvoltage then appears at the terminal of the control switch 124 coupled to the primary 104. The Zener diode 122 makes it possible to clip this overvoltage and protect the primary 104. The diode 120 then allows current to flow between the Zener diode 122, the diode 120 and the primary 104 during this phase.

[0081] In the example of [Fig.2], the control switch 124 comprises a MOSFET type transistor. One of the source or drain electrodes of this transistor can be coupled to the second terminal of the primary 104 and the other source or drain electrode of this transistor can be coupled to a reference electrical potential. In the example of [Fig.2], this transistor is of the N type and its electrode coupled to the second terminal of the primary 104 corresponds to its drain. In the presence of a fault in the circuit 1000, this transistor behaves like a current source (saturation regime) but in the absence of a fault, this transistor behaves like an on / off switch. For example, and depending on the characteristics of the transistor, the value of this current can be limited between approximately 150 mA and 200 mA for a VGS voltage of the order of 4 V, or be limited between approximately 450 mA and 500 mA for a VGS voltage of the order of 5 V.

[0082] In the example of [Fig. 2], a direct voltage VCC is applied to the first terminal of the primary 104. Thus, this voltage VCC is applied to the terminals of the primary 104 when the control switch 124 is on. The on or off state of the control switch 124 is controlled by a pulse control signal EN which, in the example of [Fig. 2], is applied to the gate of the transistor forming the control switch 124. The voltage VCC is therefore applied to the primary 104 at the frequency of the pulses of the pulse control signal EN. For example, the voltage VCC may be equal to 5 V, and the frequency of the pulse control signal EA may be equal to 10 kHz.

[0083] In the example of [Fig.2], a second terminal of the first secondary 106 is coupled to one of the terminals of the second secondary 108. Alternatively, it is possible that these terminals are not coupled to each other.

[0084] In the example of [Fig. 2], the device 100 further comprises a first current-limiting electrical resistor 126, one electrode of which is coupled to the control input of the precharge switch 1008. In [Fig. 2], the other electrode of the resistor 126 is coupled to the cathode of the voltage rectifier diode 114 and to one of the electrodes of the energy storage capacitor 116. The value of this first current-limiting electrical resistor 126 may be chosen as a function of the value of the current sent to the control input of the precharge switch 1008. Alternatively, the device 100 may not comprise this resistor 126.

[0085] In the exemplary embodiment described, the precharge switch 1008 comprises at least least one thyristor and the control input of the precharge switch 1008 corresponds to the gate of this thyristor. Alternatively, other types of switches can be used to form the precharge switch 1008, such as a TRIAC (triode for alternating current), a relay, a transistor, etc.

[0086] Furthermore, in the exemplary embodiment shown in [Fig. 2], the circuit 1000 also comprises a second current-limiting electrical resistor 1010 coupled in series to the precharge switch 1008 (to the anode of the thyristor in the example of [Fig. 2]). This resistor 1010 is intended to limit the current flowing between the source 1004 and the storage capacitor 1002, and therefore to limit the precharge current of the storage capacitor 1002. For example, the value of the second current-limiting electrical resistor 1010 may be equal to 100 Ohms. Alternatively, the second current-limiting electrical resistor 1010 may be a PTC (Positive Temperature Coefficient) thermistor.

[0087] In the first embodiment, the circuit 1000 further comprises first and second cut-off switches 1012, 1014 each coupled between one of the terminals of the source 1004 and one of the electrodes of the storage capacitor 1002. These first and second cut-off switches 1012, 1014 are intended to couple the source 1004 to the bus of the circuit 1000. In order to be able to ensure a physical cut-off between the source 1004 and the bus of the circuit 1000, at least one of the first and second cut-off switches 1012, 1014 comprises a relay, for example electromechanical. For example, the first and second cutoff switches 1012, 1014 may both correspond to relays, or one of the two cutoff switches 1012, 1014 may correspond to a relay and the other of the two cutoff switches 1012, 1014 may correspond to a semiconductor switch such as a transistor.

[0088] In the example of [Fig.2], the first cut-off switch 1012 is coupled in parallel with the precharge switch 1008 and the resistor 1010. When precharging the storage capacitor 1002, the first cut-off switch 1012 is in the blocked or open state, and the second cut-off switch 1014 is in the passing or closed state.

[0089] [Fig. 3] represents a schematic example of a timing diagram of signals obtained within the circuit 1000 according to the first embodiment previously described, in the absence of a short circuit of the storage capacitor 1002. In this figure, the signals are represented schematically with amplitudes which are not to scale with respect to each other.

[0090] In [Fig.3], the pulse control signal EN is applied to the control input of the circuit 110 (corresponding to the gate of the transistor forming the com control switch 124 in the example of [Fig.2]) between times t1 and t4. Due to the absence of a short circuit of the storage capacitor 1002, the pulse voltage across the terminals of the primary 104 causes the generation of non-zero pulse voltages across the terminals of the first and second secondaries 106, 108, which in turn cause a pulse current 1S2 to flow from the second secondary 108 through the storage capacitor 1002 and an increase in the amplitude of a control current IG1 sent to the control input of the precharge switch 1008 (corresponding to the trigger of the thyristor forming the precharge switch 1008 in the example of [Fig.2]).

[0091] In [Fig.3], the instant t2 corresponds to the instant from which the thyristor forming the precharge switch 1008 becomes conducting, due to the fact that the current 1G1 reaches a value 1GT triggering the firing of the thyristor. Between times t1 and t2, an increase in the voltage VC1 across the storage capacitor 1002 is due to the current delivered from the second secondary 108. From time t2, the voltage VC1 increases more significantly because the precharge switch 1008 is in the on state and the source 1004 is coupled to the storage capacitor 1002 via the resistor 1010 and the precharge switch 1008. From time t3, as soon as the voltage VC1 becomes greater than the voltage delivered by the second secondary 108, the current 1S2 is zero and the storage capacitor 1002 charges until it reaches the value of the voltage VBat of the source 1004 at time t5.At time t4 from which the control signal EN applied to the control input of the control switch 124 is stopped because the thyristor forming the precharge switch 1008 is in the on state, the current IG1 drops to zero. From time t5, the storage capacitor 1002 is precharged and the source 1004 can be connected to the bus by closing the first cut-off switch 1012 to limit the losses due to the resistor 1010 during operation in the steady state of the device 100.

[0092] [Fig.4] represents a schematic example of a timing diagram of signals obtained within the device 100 according to the first embodiment previously described, in the presence of a short circuit of the storage capacitor 1002. In this figure, the signals are represented schematically with amplitudes which are not to scale with respect to each other.

[0093] As in [Fig.3], the pulse control signal EN is applied to the control input of the circuit 110 between the times t1 and t4. Due to the short circuit present at the terminals of the storage capacitor 1002, the voltage at the terminals of the storage capacitor 1002 remains zero. The voltage at the terminals of the second secondary 108 is therefore also zero, which implies that the voltage at the terminals of the first secondary 106 is also zero. No control current is therefore sent to the control input of the precharge switch 1008 which therefore remains in the blocked or open state.

[0094] An example of the device 100 and the circuit 1000 according to a first variant of the first embodiment is described below in connection with [Fig.5].

[0095] In this first variant, the device 100 and the circuit 1000 comprise all the elements and components previously described in connection with [Fig. 2]. The device 100 according to this first variant further comprises a second Zener diode 128 whose cathode is coupled to the cathode of the voltage rectifier diode 114 and to one of the electrodes of the energy storage capacitor 116, and whose anode is coupled to the control input of the precharge switch 1008, i.e. the trigger of the thyristor forming this precharge switch 1008 in the example described.

[0096] This first embodiment variant may be advantageous in the presence of a short circuit forming a load coupled in parallel with the storage capacitor 1002 and generating a significant leakage current of the circuit 1000, for example of the order of ten Ohms or less. Indeed, in the presence of such a short circuit and in the absence of the second Zener diode 128, non-zero voltages may be obtained at the terminals of each of the secondaries 106, 108 and at the terminals of the voltage rectifier diode 114 when a voltage is applied to the terminals of the primary 104. In such a case, the amplitudes of the voltages obtained at the terminals of the secondaries 106, 108 depend in particular on the amplitude of the current flowing through the load formed by the short circuit and on the ratio of the number of turns of the secondaries 106, 108.A non-zero control current, for example of a few mA, can then be sent to the control input of the precharge switch 1008, which can trigger its switching to the on state and therefore the precharging of the storage capacity 1002. When the device 100 comprises the second Zener diode 128, such a control current is blocked by the second Zener diode 128, thus preventing the precharge switch 1008 from switching to the on state and therefore the precharging of the storage capacity 1002, the threshold of the second Zener diode 128 depending on the level of short-circuit leakage current.

[0097] The different configurations previously described in connection with [Fig.2] can be applied to this first variant of the first embodiment.

[0098] An example of the device 100 and the circuit 1000 according to a second variant of the first embodiment is described below in connection with [Fig.6].

[0099] In this second variant, the device 100 and the circuit 1000 comprise all the elements and components previously described in connection with [Fig. 2], with however the transformer 102 which comprises at least a third secondary 130 whose terminals are configured to be coupled to a voltage measuring device (not shown in [Fig. 6]) corresponding for example to a microcontroller. In the example of [Fig.6], a second voltage rectifier diode 132 is coupled to one of the terminals of the third secondary 130 and makes it possible to block the voltage of the third secondary 130 when it is negative, thus allowing the voltage measuring device to measure only a positive voltage.

[0100] This second variant may have the advantage of allowing a measurement of the voltage of one of the secondaries of the transformer 102, in an isolated manner and without having to connect a voltage measuring device to the first and second secondaries 106, 108. In a particular configuration, the third secondary 130 may have a number of turns similar to that of the first secondary 106, which makes it possible to have at the terminals of the third secondary 130 a voltage of a value similar to that obtained at the terminals of the first secondary 106. A measurement of a zero (or very low) voltage at the terminals of the third secondary 130 may therefore mean that a short circuit is present in the circuit 1000, in particular at the terminals of the storage capacitor 1002.

[0101] The different configurations previously described in connection with [Fig. 2] can be applied to this second variant of the first embodiment. In addition, the first and second variant embodiments described above can be combined with each other, the device 100 comprising in this case the second Zener diode 128 and a pulse transformer 102 comprising at least three secondaries 106, 108 and 130.

[0102] An example of the device 100 and the circuit 1000 according to a second embodiment is described below in connection with [Fig.7]. In this second embodiment, the circuit 1000 may be part of or form a power converter.

[0103] In this second embodiment, the source 1004 comprises an AC / DC voltage converter (the input alternating voltage is called VAC in [Fig.7]) of the totem pole type comprising at least a first arm comprising two conversion transistors 1016, 1018, for example of the MOS type, and at least a second arm comprising two conversion thyristors 1020, 1022. The triggers of the two thyristors 1020, 1022 are each coupled to a current-limiting electrical resistor 1024, 1026 and an optocoupler 1028, 1030 coupled in series with each other. In the described embodiment, each assembly comprising one of the thyristors 1020, 1022, one of the resistors 1024, 1026 and one of the optocouplers 1028, 1030 forms a precharge switch 1008 configured to be conductive during the precharge of the storage capacitor 1002.

[0104] Alternatively, it is possible that transistors 1016 and 1018 are of the IGBT (insulated gate bipolar transistor) type.

[0105] In this second embodiment, the transformer 102 comprises, in addition to the first and second secondaries 106, 108, a third secondary 130 of which a first terminal 136 is coupled to the second voltage rectifier diode 132. In the example described, the device 100 further comprises a second energy storage capacitor 134 coupled in parallel with the third secondary 130. In the example of [Fig. 1], the first terminal 136 of the third secondary 130 is coupled to one of the electrodes of the second energy storage capacitor 134 via the second voltage rectifier diode 132, the second energy storage capacitor 134 here being coupled in parallel with the assembly formed by the third secondary 130 and the second voltage rectifier diode 132. In the example of [Fig. 7], the cathode of the second voltage rectifier diode 132 is coupled to one of the electrodes of the second energy storage capacitor 134 and the anode of the second voltage rectifier diode 132 is coupled to the first terminal 136 of the third secondary 130.

[0106] The first terminal 112 of the first secondary 106 is coupled, via the first voltage rectifier diode 114, to the control input of one of the precharge switches 1008 formed by an input electrode of the optocoupler 1028, and the first terminal 136 of the third secondary 130 is coupled, via the second voltage rectifier diode 132, to the control input of the other of the precharge switches 1008 formed by an input electrode of the optocoupler 1030.

[0107] The operation of the device 100 and the circuit 1000 according to the second embodiment is substantially similar to that previously described for the device 100 and the circuit 1000 according to the first embodiment. In the presence of a short circuit of the storage capacitor 1002, the voltages across each of the secondaries 106, 108, 130 are zero, and no control current is sent to the input electrodes of the optocouplers 1028, 1030. In the absence of a short circuit of the storage capacitor 1002, the voltages across each of the secondaries 106, 108, 130 are non-zero, and unharmed control currents are then sent to the input electrodes of the optocouplers 1028, 1030, thus triggering the switching on of the thyristors 1020, 1022 via the circulation of a current in the gates of the thyristors 1020, 1022, and the precharging of the storage capacitor 1002.

[0108] As a variant of this second embodiment, the device 100 may comprise, as in the first variant of the first embodiment previously described, Zener diodes whose cathode is coupled to the cathode of the voltage rectifier diodes 114, 132 and whose anode is coupled to the input electrode of each of the optocouplers 1028, 1030. It is also possible for the pulse transformer 102 to comprise, as in the second variant of the first embodiment previously described, a fourth secondary whose terminals are configured to be coupled to a voltage measuring device.

[0109] The different configurations previously described in connection with the first mode embodiments may be applied to the device 100 and to the circuit 1000 according to the second embodiment.

[0110] An example of the device 100 and the circuit 1000 according to a third embodiment is described below in connection with [Fig.8]. In this third embodiment, the circuit 1000 may be part of or form a power converter.

[0111] In this third embodiment, the source 1004 comprises an AC / DC voltage converter of the Boost PFC (Power Factor Correction) type with a mixed bridge comprising at least two conversion diodes 138, 140 and two conversion thyristors 1020, 1022. The triggers of the two thyristors 1020, 1022 are each coupled to a current-limiting electrical resistor 1024, 1026 and an optocoupler 1028, 1030 coupled in series with each other. As in the second embodiment previously described, each assembly comprising one of the thyristors 1020, 1022, one of the resistors 1024, 1026 and one of the optocouplers 1028, 1030 forms a precharge switch 1008 configured to be conductive when precharging the storage capacitor 1002.

[0112] Alternatively, it is possible that the conversion diodes 138, 140 are replaced by thyristors.

[0113] The first terminal 112 of the first secondary 106 is coupled, via the voltage rectifier diode 114, to the control input of the precharge switches 1008 formed by an input electrode of each of the optocouplers 1028, 1030. Thus, the current from the first secondary 106 is intended to form the control current of the precharge switch 1008.

[0114] In the example of [Fig.8], the circuit 1000 further comprises a MOSFET type transistor 142, for example similar to the transistor 124 of the circuit 110. The pulse control signal EN is applied to the gate of this transistor 142. The source and drain electrodes of this transistor 142 are coupled to the electrodes of the storage capacitor 1002 such that the transistor 142 is coupled in parallel with the storage capacitor 1002. Furthermore, an inductor 144 is coupled to one of the electrodes of the storage capacitor 1002.

[0115] When the transistor 142 is on, a current flows in the inductor 144 which then accumulates energy. When the transistor 142 is off, the energy accumulated in the inductor 144 is sent to the storage capacitor 1002. The transistor 142 can be controlled such that the mains current is sinusoidal and in phase with the mains voltage thanks to a regulation carried out via this transistor 142.

[0116] The operation of the device 100 and the circuit 1000 according to the third embodiment is substantially similar to that previously described for the device 100 and the circuit 1000 according to the first and second embodiments. In the presence of a short circuit of the storage capacitor 1002, the voltages across each of the secondaries 106, 108 are zero, and no control current is sent to the input electrodes of the optocouplers 1028, 1030. In the absence of a short circuit of the storage capacitor 1002, the voltages across each of the secondaries 106, 108 are non-zero, and a non-zero control current is then sent to the input electrodes of the optocouplers 1028, 1030, thus triggering the switching on of the thyristors 1020, 1022 via the circulation of a current in the gates of the thyristors 1020, 1022 and the precharging of the storage capacitor 1002.

[0117] As a variant of this third embodiment, the device 100 may comprise, as in the first variant of the first embodiment previously described, a Zener diode whose cathode is coupled to the cathode of the voltage rectifier diode 114 and whose anode is coupled to the input electrode of each of the optocouplers 1028, 1030. It is also possible for the pulse transformer 102 to comprise, as in the second variant of the first embodiment previously described, a fourth secondary whose terminals are configured to be coupled to a voltage measuring device.

[0118] The different configurations previously described in connection with the first and second embodiments can be applied to the device 100 and to the circuit 1000 according to the third embodiment.

[0119] An example of the device 100 and the circuit 1000 according to a fourth embodiment is described below in connection with [Fig.9]. In this fourth embodiment, the circuit 1000 may be part of or form a power converter.

[0120] In this fourth embodiment, the source 1004 comprises an AC / DC voltage converter of the Boost PFC type comprising at least one diode bridge 150 (in [Fig.9], four conversion diodes forming the diode bridge 150 are referenced 138, 140, 146 and 148).

[0121] In this fourth embodiment, the precharge switch 1008, configured to be on during the precharge of the storage capacity 1002, comprises a thyristor whose trigger, forming the control input of the precharge switch 1008, is coupled to a current limiting resistor 1024 and an optocoupler 1028.

[0122] The other elements of the device 100 and of the circuit 1000 are similar to those previously described in connection with the third embodiment.

[0123] The operation of the device 100 and the circuit 1000 according to this fourth embodiment is substantially similar to that previously described for the device 100 and the circuit 1000 according to the previous embodiments. In the presence of a short circuit of the storage capacitor 1002, the voltages at the terminals of each of the secondaries 106, 108 are zero, and no control current is sent to the input electrode of the optocoupler 1028. In the absence of a short circuit of the storage capacity 1002, the voltages across each of the secondaries 106, 108 are non-zero, and a non-zero control current is then sent to the input electrode of the optocoupler 1028, thus triggering the switching on of the thyristor forming the load switch 1008 via the circulation of a current in its trigger and the precharging of the storage capacity 1002.

[0124] In all embodiments, examples and variants, the thyristor(s), or SCR(s) (“Silicon Controlled Rectifier”), used to form the load switch(es) 1008 may be replaced by other types of switch, such as for example TRIACs, relays or even transistors.

[0125] In the second, third and fourth embodiments previously described, the source 1004 comprises an AC / DC converter. Alternatively, it is possible for the source 1004 to comprise a DC / DC converter, or a transformer such as a Flyback converter.

[0126] As a variant of the exemplary embodiment of the precharge control circuit 110 previously described in the different embodiments, it is possible for the circuit 110 to comprise a microcontroller and / or a DSP to control the primary 104 of the pulse transformer 102.

[0127] The values ​​of the various elements previously described may be different from the examples previously cited, these values ​​being a function in particular of the applications and the operating environment of the device 100 and the circuit 1000.

[0128] The device 100 makes it possible to improve the protection of the direct current circuit 1000 by using a pulse transformer 102 to detect, using one of the secondaries of the transformer 102, a possible fault in the circuit 1000 such as a short circuit of the storage capacitor 1002, and to allow or not, after the detection or not of a fault and using the other or other secondaries of the transformer 102, the precharging of the storage capacitor 1002. The short-circuit detection and precharging control functions are therefore implemented at the same time, from the same pulse transformer.

[0129] For example, when a thyristor is used as a precharge switch, the device 100 can for example prevent triggering of the thyristor in the presence of a short circuit of the storage capacitor 1002 or a fault such as a leak in the circuit 1000. When a relay is used as a precharge switch, the device 100 makes it possible to perform a short circuit or fault detection in the circuit 1000 without having to close the relay to perform this detection.

[0130] The device 100 allows rapid detection of a short circuit or leakage fault in the direct current circuit 1000. Furthermore, the device 100 does not require a circuit dedicated solely to blocking the precharge switch.

[0131] The device 100 can be used in particular in battery control systems (or BMS for “Battery Management System” in English), electric vehicles, or even in power conversion structures for example of the totem pole type, mixed bridges, etc.

[0132] The device is for example intended for the automotive industry. The electrification of motor vehicles generates an increasingly high level of electronic content in the vehicles. The device comprises for example thyristors, rectifiers, high voltage transient voltage suppression diodes, modules, etc. intended to be incorporated in said vehicles. The automation of driving also generates an increasingly high electronic content in the vehicles. The device comprises for example high voltage transient voltage suppression diodes, electromagnetic discharge protection and common mode filters to protect against electrical hazards in emerging complex electronics.

[0133] The device can for example be used in the industrial field. More particularly, the device aims for example to be used for the development of green energies or for the electrification of infrastructures, for example for charging stations or for the incorporation of solar energy. The device is for example intended to be implemented in the power and energy circuits of equipment, comprising for example 800V or 1200V thyristors, ultrafast 1200V and silicon carbide diodes, transient voltage suppression diodes, and protections against electromagnetic discharges. The device can also be used in the implementation of data centers and servers. The device comprises for example wide band gap materials.

[0134] The device is for example intended to be used in communication equipment, or in computers and peripherals. For example, the device can be used in 5G infrastructures and dedicated data centers. The device comprises for example silicon carbide diodes, power Schottky transistors, electromagnetic discharge protections and transient voltage suppression diodes. The device can also be used in satellites, comprising for example integrated passive devices for radio frequency applications.

[0135] The device can be used for any type of AC / DC or DC / DC converter.

[0136] The described solution can be used to control any type of precharge switch: thyristor, MOSFET, relay, IGBT, etc.

[0137] Various embodiments and variations have been described. Those skilled in the art will understand that certain features of these various embodiments and variations could be combined, and other variations will occur to those skilled in the art. job.

[0138] Finally, the practical implementation of the embodiments and variants described is within the reach of those skilled in the art from the functional indications given above.

Claims

Claims

1. Device (100) for controlling precharging of a storage capacity (1002) and for detecting a fault in a direct current circuit (1000) which comprises the storage capacity (1002), at least one direct voltage source (1004) and at least one first precharging switch (1008) coupled to an electrode of the storage capacity (1002), the device (100) comprising at least: - a pulse transformer (102) provided with a primary (104) and at least one first and one second secondary (106, 108); - a circuit (110) for controlling precharging of the storage capacity (1002), coupled to the primary (104) of the pulse transformer (102);wherein the first secondary (106) of the pulse transformer (102) has a first terminal (112) configured to be coupled to a control input of the first precharge switch (1008), and wherein the second secondary (108) of the pulse transformer (102) is configured to be coupled in parallel with the storage capacitor (1002).;

2. The device (100) of claim 1, further comprising at least one first energy storage capacitor (116) coupled in parallel with the first secondary (106) of the pulse transformer (102).

3. Device (100) according to any one of the preceding claims, further comprising at least one first voltage rectifier diode (114) whose anode is coupled to the first terminal (112) of the first secondary (106) of the pulse transformer (102), and / or at least one first current limiting electrical resistor (126) whose electrode is configured to be coupled to the control input of the first precharge switch (1008).

4. The device (100) of claim 3, further comprising at least one second Zener diode (128) whose cathode is coupled to the cathode of the first voltage rectifier diode (114) and whose anode is configured to be coupled to the control input of the first precharge switch (1008).

5. Device (100) according to any one of the preceding claims, further comprising at least one second protection diode (118) coupled in series to the second secondary (108) of the pulse transformer (102).

6. Device (100) according to any one of the preceding claims, wherein the circuit (110) for controlling precharging of the storage capacity (1002) comprises at least: - a third diode (120) whose cathode is coupled to a first terminal of the primary (104) of the pulse transformer (102); - a first Zener diode (122) whose anode is coupled to the anode of the third diode (120) and whose cathode is coupled to a second terminal of the primary (104) of the pulse transformer (102); - a control switch (124) coupled to the second terminal of the primary (104) of the pulse transformer (102).

7. A device (100) according to any preceding claim, wherein a second terminal of the first secondary (106) of the pulse transformer (102) is coupled to one of the terminals of the second secondary (108) of the pulse transformer (102).

8. Device (100) according to any one of the preceding claims, wherein the pulse transformer (102) comprises at least one third secondary (130) whose terminals are configured to be coupled to a voltage measuring device or to a control input of a second precharge switch (1008).

9. Direct current circuit (1000), comprising at least: - a direct voltage source (1004); - a bus comprising at least two conductive elements (1006) each coupled to one of the terminals of the direct voltage source (1004); - a capacitive element forming a storage capacitor (1002) each of whose electrodes is coupled to one of the two conductive elements (1006) of the bus; - a first precharge switch (1008) coupled to an electrode of the storage capacitor (1002); - a device (100) for controlling precharge of the storage capacitor (1002) and for detecting faults in the circuit

10.

11.

12.

13. direct current (1000) according to any one of the preceding claims. The direct current circuit (1000) of claim 9, wherein the direct current voltage source (1004) comprises at least one battery. The direct current circuit (1000) of claim 10, wherein the first precharge switch (1008) comprises at least one first thyristor and the control input of the first precharge switch (1008) corresponds to the gate of the first thyristor, and further comprising at least: - a second current-limiting electrical resistor (1010) coupled in series with the first thyristor; - first and second cut-off switches (1012, 1014) each coupled between one of the terminals of the direct voltage source (1004) and one of the electrodes of the storage capacitor (1002), at least one of the first and second cut-off switches (1012, 1014) comprising a relay. The direct current circuit (1000) of claim 11, wherein one of the first and second cutoff switches (1012) is coupled in parallel with the first thyristor and the second current limiting electrical resistor (1010). A direct current circuit (1000) according to claim 9, wherein: - the DC voltage source (1004) comprises a totem pole type AC / DC voltage converter comprising at least two conversion transistors (1016, 1018) and at least two conversion thyristors (1020, 1022) whose triggers are each coupled to a third current limiting electrical resistor (1024, 1026) and an optocoupler (1028, 1030) coupled in series with each other and forming first and second precharge switches (1008); - the pulse transformer (102) of the device (100) comprises at least a third secondary (130); - the first terminal (112) of the first secondary (106) of the pulse transformer (102) of the device (100) is coupled to an input electrode of one of the optocouplers (1028); and - a first terminal (136) of the third secondary (130) of the pulse transformer (102) of the device (100) is coupled to an input electrode of the other of the optocouplers (1030).

14. Direct current circuit (1000) according to claim 9, wherein: - the direct current voltage source (1004) comprises a mixed bridge Boost PFC type AC / DC voltage converter comprising at least two conversion diodes (138, 140) and at least two conversion thyristors (1020, 1022), or at least four conversion thyristors (1020, 1022), the gates of which are each coupled to a third current limiting electrical resistor (1024, 1026) and an optocoupler (1028, 1030) coupled in series with each other and forming first and second precharge switches (1008); and - the first terminal (112) of the first secondary (106) of the pulse-forming transformer (102) of the device (100) is coupled to an input electrode of each of the optocouplers (1028, 1030).

15. Direct current circuit (1000) according to claim 9, wherein: - the direct current voltage source (1004) comprises a diode bridge Boost PFC type AC / DC voltage converter (150); - the first precharge switch (1008) comprises at least a first thyristor, a third current limiting electrical resistor (1024) and an optocoupler (1028) coupled in series with each other.

Images