Device for controlling precharging of a high capacity capacitor and for detecting fault in

Abstract

The present description relates to an apparatus for controlling pre-charging of a mass capacitor and for detecting a fault in a DC current circuit comprising a mass capacitor, at least one DC voltage source, and at least a first pre-charge switch coupled to an electrode of the mass capacitor. The device comprises at least a pulse transformer provided with a primary coil and at least a first secondary coil and a second secondary coil, and a circuit for controlling the pre-charging of the bulk capacitor, the circuit being coupled to the primary coil of the pulse transformer. A first secondary coil of the pulse transformer includes a first terminal configured to be coupled to a control input of the first pre-charge switch. A second secondary coil of the pulse transformer is configured to be coupled in parallel with the bulk capacitor.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to French patent application No. 24 / 03255, filed on March 29, 2024, entitled “Dispositif de commande de précharge d'une capacitéde stockage et de détection de défaut dans un circuit à courant continu,” which is incorporated herein by reference to the fullest extent permitted by law. Technical Field

[0003] The present disclosure relates generally to the field of DC current circuits. Background Art

[0004] In a DC current circuit, a bus comprising at least two conducting elements is coupled, on the one hand, to a DC voltage source, such as a battery or the output of a DC / DC or AC / DC converter, and, on the other hand, to a component of the circuit comprising a capacitive element, which can generally be similar to a bulk capacitor. This bulk capacitor is coupled in parallel with the DC voltage source via the conducting elements of the bus and via at least a switch, which enables the DC voltage source to be coupled to or decoupled from the bus.

[0005] When the switch is turned on or closed to couple the bus to the DC voltage source, a significant inrush current flows between the DC voltage source and the bulk capacitor. To avoid this inrush current, the bulk capacitor can be precharged by passing a precharge current through the bulk capacitor before the switch is turned on. This precharge phase is implemented for a period of time sufficient to achieve the desired precharge voltage across the bulk capacitor.

[0006] However, during this pre-charging phase of the bulk capacitors, if there is a fault on the bus, such as, for example, a short circuit or significant current leakage, very high currents may circulate in the bus and damage other elements of the circuitry coupled to the bus.

[0007] When a thyristor is used as a switch to couple a DC voltage source to a bus during the pre-charging of a bulk capacitor, it is not possible to switch off this thyristor in the event of a fault in the circuit due to the fact that the current it conducts is still very high. Switching off the thyristor to stop the circulation of such a high current requires the use of an additional circuit dedicated to this function.

[0008] When an electromechanical relay is used as a switch to couple a DC voltage source to a bus during the pre-charging period of a bulk capacitor, a short circuit in the bulk capacitor can be detected. However, this detection is only possible when the relay is closed, leaving a specific period of time before detection during which circulating current can damage components of the circuit. Furthermore, the delay in opening the electromechanical relay is long and increases over time. Summary of the Invention

[0009] There is a need to provide a solution that makes it possible to detect the presence of a fault in a DC current circuit before performing a pre-charging of the bulk capacitor of the circuit in the absence of such a fault.

[0010] One embodiment overcomes all or part of the disadvantages of known solutions and provides an apparatus for controlling the pre-charging of a bulk capacitor and for detecting faults in a DC current circuit, the DC current circuit including a bulk capacitor, at least one DC voltage source, and at least a first pre-charging switch coupled to an electrode of the bulk capacitor, the apparatus comprising at least: a pulse transformer having a primary winding and at least a first secondary winding and a second secondary winding; and a circuit for controlling the pre-charging of the bulk capacitor, the circuit being coupled to the primary winding of the pulse transformer. The first secondary winding of the pulse transformer includes a first terminal configured to be coupled to a control input of the first pre-charging switch, and wherein the second secondary winding of the pulse transformer is configured to be coupled in parallel with the bulk capacitor.

[0011] In certain embodiments, the apparatus further includes at least a first power storage capacitor coupled in parallel with the first secondary winding of the pulse transformer.

[0012] In a particular embodiment, the device also includes: at least a first voltage rectifier diode, the anode of which is coupled to the first terminal of the first secondary winding of the pulse transformer; and / or at least a first current limiting resistor, the electrode of which is configured to be coupled to the control input of the first pre-charge switch.

[0013] In a particular embodiment, the apparatus further includes at least a second Zener diode having a cathode coupled to a cathode of the first voltage rectifier diode and an anode configured to be coupled to the control input of the first pre-charge switch.

[0014] In certain embodiments, the apparatus further includes at least a second protection diode coupled in series with the second secondary winding of the pulse transformer.

[0015] In a particular embodiment, a circuit for controlling pre-charging of a bulk capacitor includes at least: a third diode having a cathode coupled to a first terminal of the primary winding of a pulse transformer; a first Zener diode having an anode coupled to an anode of the third diode and a cathode coupled to a second terminal of the primary winding of the pulse transformer; and a control switch coupled to the second terminal of the primary winding of the pulse transformer.

[0016] In a particular embodiment, the second terminal of the first secondary winding of the pulse transformer is coupled to one of the terminals of the second secondary winding of the pulse transformer.

[0017] In a particular embodiment, the pulse transformer includes at least a third secondary winding having a terminal configured to be coupled to a voltage measurement device or a control input of the second pre-charge switch.

[0018] Another embodiment provides a DC current circuit according to a specific embodiment, the DC current circuit comprising at least: a DC voltage source; a bus comprising at least two conductive elements, each conductive element coupled to one of the terminals of the DC voltage source; a capacitive element forming a bulk capacitor, each electrode of which is coupled to one of the two conductive elements of the bus; a first pre-charging switch coupled to an electrode of the bulk capacitor; and a device for controlling the pre-charging of the bulk capacitor and for detecting a fault in the DC current circuit.

[0019] In certain embodiments, the DC voltage source includes at least a battery.

[0020] In a particular embodiment, the first pre-charge switch includes at least a first thyristor, and a control input of the first pre-charge switch corresponds to a gate of the first thyristor, and the circuit further includes at least: a second current limiting resistor coupled in series with the first thyristor; and a first disconnect switch and a second disconnect switch, each disconnect switch coupled between one of the terminals of the DC voltage source and one of the electrodes of the bulk capacitor, at least one of the first disconnect switch and the second disconnect switch comprising a relay.

[0021] In a particular embodiment, one of the first disconnect switch and the second disconnect switch is coupled in parallel with the first thyristor and with the second current limiting resistor.

[0022] In a specific embodiment: the DC voltage source includes a totem pole type AC / DC voltage converter, which includes at least two conversion transistors and at least two conversion thyristors, and the gates of the conversion transistors and the conversion thyristors are each coupled to a third current limiting resistor and an optocoupler that are coupled in series with each other and form a first pre-charge switch and a second pre-charge switch; the pulse transformer of the device includes at least a third secondary winding; the first terminal of the first secondary winding of the pulse transformer of the device is coupled to the input electrode of one of the optocouplers; and the first terminal of the third secondary winding of the pulse transformer of the device is coupled to the input electrode of another optocoupler.

[0023] In a specific embodiment: the DC voltage source includes a Boost PFC type AC / DC voltage converter with a hybrid bridge, the voltage converter including at least two switching diodes and at least two switching thyristors, or at least four switching thyristors, the gate of each switching thyristor being coupled to a third current limiting resistor and an optocoupler that are coupled in series with each other and form a first pre-charge switch and a second pre-charge switch; and the first terminal of the first secondary winding of the pulse transformer of the device is coupled to the input electrode of each optocoupler.

[0024] In a particular embodiment: the DC voltage source comprises an AC / DC voltage converter of the Boost PFC type having a diode bridge; and the first pre-charging switch comprises at least a first thyristor, a third current limiting resistor and an optocoupler coupled in series with each other.

[0025] Another embodiment provides a method for controlling the pre-charging of a bulk capacitor and detecting faults in a DC current circuit, the DC current circuit comprising a bulk capacitor, at least one DC voltage source, and at least a first pre-charging switch coupled to an electrode of the bulk capacitor. The method utilizes a pulse transformer having a primary coil and at least a first secondary coil and a second secondary coil, and also utilizes a circuit for controlling the pre-charging of the bulk capacitor, the circuit being coupled to the primary coil of the pulse transformer. In this method, the first secondary coil comprises a first terminal coupled to a control input of the first pre-charging switch, and the second secondary coil is coupled in parallel with the bulk capacitor.

[0026] In certain embodiments, the method includes sending a control signal to the primary winding of the pulse transformer via a circuit for controlling precharging of a bulk capacitor. In the absence of a fault in the DC circuit, the method involves generating a voltage at the terminals of the first and second secondary windings and sending a current to a control input of a first precharge switch that triggers precharging of the bulk capacitor. In the presence of a fault in the DC circuit, the method involves maintaining a zero voltage or a very low voltage at the terminals of the first and second secondary windings and maintaining the first precharge switch in a blocked state, thereby preventing precharging of the storage capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The foregoing features and advantages, as well as other features and advantages, will be described in detail in the remainder of the disclosure of specific embodiments given by way of illustration and not limitation, with reference to the accompanying drawings, in which:

[0028] Figure 1 schematically illustrates an example of implementation of a device for controlling pre-charging of a bulk capacitor and for detecting faults in a DC current circuit;

[0029] Figure 2 schematically illustrates a device for controlling pre-charging of a bulk capacitor and for detecting faults in a DC current circuit according to a first embodiment;

[0030] Figure 3 shows a simplified timing diagram of signals obtained within the device for controlling pre-charging of a bulk capacitor and for detecting faults in a DC current circuit according to a first embodiment in the absence of a fault in the circuit;

[0031] Figure 4 shows a simplified timing diagram of signals obtained within a device for controlling pre-charging of a bulk capacitor and for detecting a fault in a DC current circuit according to a first embodiment in the presence of a fault in the circuit;

[0032] Figure 5 schematically illustrates a device for controlling the pre-charging of a bulk capacitor and for detecting a fault in a DC current circuit according to a first variant of the first embodiment;

[0033] Figure 6 schematically illustrates a device for controlling the pre-charging of a bulk capacitor and for detecting a fault in a DC current circuit according to a second variant of the first embodiment;

[0034] Figure 7 schematically illustrates a device for controlling pre-charging of a bulk capacitor and for detecting faults in a DC current circuit according to a second embodiment;

[0035] Figure 8 schematically illustrates a device for controlling pre-charging of a bulk capacitor and for detecting faults in a DC current circuit according to a third embodiment; and

[0036] Figure 9 A device for controlling the pre-charging of a bulk capacitor and for detecting faults in a DC current circuit according to a fourth embodiment is schematically shown. DETAILED DESCRIPTION

[0037] Like features in the various figures are denoted by like reference numerals. In particular, common structural and / or functional features between various embodiments may have the same reference numerals and may be arranged in the same structure, dimensions, and material properties.

[0038] For the sake of clarity, only those steps and elements that are useful for understanding the described embodiments are shown and described in detail. In particular, the various elements of the apparatus for controlling the pre-charging of the bulk capacitor and the fault detection in the DC current circuit (voltage source, bus, switch, control circuit, transformer, etc.) are not described in detail. A person skilled in the art will be able to implement these elements in detail based on the functional descriptions given herein.

[0039] Unless otherwise indicated, when two elements are referred to as being connected together, this means a direct connection without any intervening elements other than conductors, and when two elements are referred to as being coupled together, this means the two elements may be connected or they may be coupled via one or more other elements.

[0040] Unless otherwise indicated, the term "conduction" is used to mean electrical conduction.

[0041] Throughout this document, the term "fault" is used in relation to a DC current circuit to denote an electrical fault present in the circuit, such as a short circuit of a bulk capacitor or a significant current leakage.

[0042] Unless otherwise specified, the expressions "about," "approximately," "substantially," and "around" mean plus or minus 10%, preferably plus or minus 5%.

[0043] Below is about Figure 1 An example of an embodiment of a device 100 for controlling pre-charging of a bulk capacitor 1002 and for detecting a fault in a DC current circuit 1000 in which the bulk capacitor 1002 is located is described.

[0044] The circuit 1000 includes at least one DC voltage source 1004 , including, for example, one or more batteries and / or at least one DC / DC or AC / DC converter. However, other types of DC voltage sources may be included in the circuit 1000 .

[0045] The circuit 1000 also comprises a bus for the circulation of a DC current in the circuit 1000 and comprising at least two conductive elements 1006, each conductive element being coupled to one of the terminals of the source 1004. In the example of the embodiment described, the source 1004 is intended to apply a DC voltage to these conductive elements 1006 and to deliver a DC current that circulates through the conductive elements 1006 of the bus.

[0046] Circuit 1000 also includes other electrical components coupled to the bus and forming one or more capacitive electrical elements, generally similar to bulk capacitor 1002. Each electrode of bulk capacitor 1002 is coupled to one of two conductive elements 1006 of the bus of circuit 1000.

[0047] The circuit 1000 also includes at least one pre-charge switch 1008 coupled to one of the electrodes of the bulk capacitor 1002. Figure 1 In the example of FIG, the pre-charge switch 1008 is included in the source 1004. As a variation, the pre-charge switch 1008 can be a different element from the source 1004. The pre-charge switch 1008 can be coupled between the first terminal of the source 1004 and one of the electrodes of the bulk capacitor 1002.

[0048] The circuit 1000 further comprises an apparatus 100 for controlling the pre-charging of the bulk capacitor 1002 and for detecting faults in the circuit 1000 .

[0049] Device 100 includes at least one pulse transformer 102 having a primary coil 104 and at least one first secondary coil 106 and a second secondary coil 108, wherein primary coil 104 is magnetically coupled to first secondary coil 106 and second secondary coil 108. First secondary coil 106 and second secondary coil 108 may be similar to or different from each other in terms of the number of windings. The electrical characteristics of transformer 102 may be selected, in particular, according to the voltage and current levels to which the components of transformer 102 are to be subjected.

[0050] The device 100 further comprises a circuit 110 for controlling pre-charging of the bulk capacitor 1002, which is coupled to the primary coil 104. In the example of the described embodiment, the circuit 110 is intended to apply a voltage in the form of pulses across the primary coil 104 during pre-charging of the bulk capacitor 1002.

[0051] The first secondary winding 106 includes a first terminal 112 coupled to a control input of the pre-charge switch 1008. Figure 1In the example of , the first terminal 112 of the first secondary winding 106 is coupled to the control input of the pre-charge switch 1008 via a voltage rectifier diode 114 , the anode of which is coupled to the first terminal 112 and the cathode of which is coupled to the control input of the pre-charge switch 1008 .

[0052] In the example of the embodiment being described, the device 100 further comprises a power storage capacitor 116 coupled in parallel with the first secondary coil 106 and intended to form the power supply for controlling the pre-charging switch 1008. Figure 1 In the example of , the first terminal 112 of the first secondary coil 106 is coupled via a voltage rectifier diode 114 to one of the electrodes of a power storage capacitor 116, which is here coupled in parallel with the assembly formed by the first secondary coil 106 and the voltage rectifier diode 114. Figure 1 In the example shown, the cathode of the voltage rectifier diode 114 is coupled to one of the electrodes of the power storage capacitor 116 and the anode of the voltage rectifier diode 114 is coupled to the first terminal 112 of the first secondary coil 106. Given a voltage variation across the first secondary coil 106, when the voltage across the first secondary coil 106 is positive, the voltage rectifier diode 114 enables the power storage capacitor 116 to be charged at a constant DC voltage.

[0053] The second secondary winding 108 is coupled in parallel with the bulk capacitor 1002. Figure 1 In the example of , the device 100 further includes a protection diode 118 coupled in series with the second secondary winding 108 and preventing the bulk capacitor 1002 from discharging through the second secondary winding 108 when the bulk capacitor 1002 is pre-charged, while allowing current to flow between the bulk capacitor 1002 and the second secondary winding 108 during the fault presence check phase. Figure 1 In the specific configuration shown in FIG, the cathode of the protection diode 118 is coupled to one of the terminals of the second secondary winding 108 and the anode of the protection diode 118 is coupled to one of the electrodes of the bulk capacitor 1002. Figure 1 In the example of FIG. 1 , a bulk capacitor 1002 is coupled in parallel with the assembly formed by the second secondary winding 108 and the protection diode 118 .

[0054] In this circuit 1000 including device 100, when the purpose is to precharge bulk capacitor 1002, for example, before connecting source 1004 to a bus, circuit 110 controls transformer 102 in such a way that a non-zero pulsed voltage is applied across primary winding 104. In the absence of a fault, and in particular, when there is no short circuit across bulk capacitor 1002, a first non-zero pulsed voltage is generated across first secondary winding 106, and a second non-zero pulsed voltage is generated across second secondary winding 108. The second voltage across second secondary winding 108 charges bulk capacitor 1002, for example, by several volts, while the first voltage across first secondary winding 106 generates a current that circulates through power storage capacitor 116, thereby increasing the potential difference across power storage capacitor 116. This potential difference across power storage capacitor 116 generates a control current that is sent to the control input of pre-charge switch 1008, which, when switched on, triggers pre-charging of bulk capacitor 1002.

[0055] However, in the presence of a fault, such as a short circuit across bulk capacitor 1002, the voltage across second secondary winding 108 remains zero despite the voltage applied to primary winding 104 by circuit 110. Consequently, the voltage across first secondary winding 106 also remains zero. Consequently, no current flows to charge power storage capacitor 116, and no control current is sent to the control input of pre-charge switch 1008. Due to the fact that pre-charge switch 1008 remains in the open state, pre-charging of bulk capacitor 1002 is not triggered.

[0056] Therefore, the transformer 102 performs two functions simultaneously: the first secondary winding 106 is used to control the conduction state of the pre-charge switch 1008 according to the presence or absence of a fault in the circuit 1000 , and the second secondary winding 108 is used to detect the presence or absence of a fault in the circuit 1000 .

[0057] The following is about Figure 2 An example of a device 100 and a circuit 1000 according to a first embodiment is described. In this first embodiment, the circuit 1000 may form part of or form a system for controlling a vehicle battery.

[0058] In a first embodiment, the source 1004 includes one or more batteries that deliver a DC voltage VBat. For example, the one or more batteries of the source 1004 may correspond to one or more batteries of an electric vehicle, where the voltage delivered across the source 1004 may be equal to approximately 400V or 800V or another value.

[0059] exist Figure 2In the example of FIG. 1 , the circuit 110 includes at least: a diode 120 having a cathode coupled to a first terminal of the primary coil 104; a Zener diode 122 having an anode coupled to an anode of the diode 120 and a cathode coupled to a second terminal of the primary coil 104; and a control switch 124 configured to control a voltage pulse applied across the primary coil 104.

[0060] Diodes 120 and 122 form a demagnetization circuit for transformer 102. In the first phase, control switch 124 is closed and current flows through primary coil 104. When primary coil 104 is blocked by opening control switch 124, the power stored in transformer 102 must be depleted. An overvoltage then appears at the terminals of control switch 124 coupled to primary coil 104. Zener diode 122 serves to clamp this overvoltage and protect primary coil 104. During this phase, diode 120 allows current to flow between Zener diode 122, diode 120, and primary coil 104.

[0061] exist Figure 2 In the example of , the control switch 124 includes a MOSFET type transistor. One of the source or drain electrodes of this transistor can be coupled to the second terminal of the primary coil 104, and the other source or drain electrode of this transistor can be coupled to the reference potential. Figure 2 In the example shown, this transistor is of N-type, and its electrode coupled to the second terminal of primary coil 104 corresponds to its drain. When a fault is present in circuit 1000, this transistor behaves like a current source (saturation state), but when a fault is not present, 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 to between approximately 150 mA and 200 mA for a voltage VGS of approximately 4 V, or between approximately 450 mA and 500 mA for a voltage VGS of approximately 5 V.

[0062] exist Figure 2 In the example, the DC voltage VCC is applied to the first terminal of the primary coil 104. Therefore, when the control switch 124 is turned on, the voltage VCC is applied to both ends of the primary coil 104. The on or off state of the control switch 124 is controlled by the pulse control signal EN. Figure 2 In the example shown, the control signal EN is applied to the gate of the transistor forming the control switch 124. Therefore, the voltage VCC is applied to the primary coil 104 at the frequency of the pulses of the pulse control signal EN. For example, the voltage VCC may be equal to 5V, and the frequency of the pulse control signal EN may be equal to 10kHz.

[0063] exist Figure 2In the example of FIG, the second terminal of the first secondary winding 106 is coupled to one of the terminals of the second secondary winding 108. As a variant, it is possible that these terminals are not coupled to each other.

[0064] exist Figure 2 In the example of , the device 100 further includes a first current limiting resistor 126 having an electrode coupled to the control input of the pre-charge switch 1008. Figure 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 power storage capacitor 116. The value of this first current limiting resistor 126 can be selected according to the value of the current sent to the control input of the pre-charge switch 1008. As a variant, it is possible that the device 100 does not include this resistor 126.

[0065] In the example of the embodiment described, the pre-charge switch 1008 includes at least one thyristor, and the control input of the pre-charge switch 1008 corresponds to the gate of the thyristor. As a variant, other types of switches can be used to form the pre-charge switch 1008, such as, for example, TRIAC (Triode for AC Current), relays, transistors, etc.

[0066] In addition, Figure 2 In the example of the embodiment shown in FIG, the circuit 1000 further includes a second current limiting resistor 1010 coupled in series with the pre-charge switch 1008 ( Figure 2 In the example shown in FIG. 1 , the second current limiting resistor 1010 is coupled in series with the anode of the thyristor. This resistor 1010 is intended to limit the current circulating between the source 1004 and the bulk capacitor 1002, thereby limiting the pre-charge current of the bulk capacitor 1002. For example, the value of the second current limiting resistor 1010 may be equal to 100 ohms. Alternatively, the second current limiting resistor 1010 may be a PTC (positive temperature coefficient) type thermistor.

[0067] In a first embodiment, circuit 1000 further includes a first disconnect switch 1012 and a second disconnect switch 1014, each of which is coupled between one of the terminals of source 1004 and one of the electrodes of bulk capacitor 1002. These first disconnect switches 1012 and second disconnect switches 1014 are intended to couple source 1004 to a bus of circuit 1000. To ensure a physical disconnect between source 1004 and the bus of circuit 1000, at least one of first disconnect switches 1012 and second disconnect switches 1014 comprises a relay, such as an electromechanical relay. For example, both first disconnect switch 1012 and second disconnect switch 1014 may correspond to relays, or one of the two disconnect switches 1012 and 1014 may correspond to a relay, and the other of the two disconnect switches 1012 and 1014 may correspond to a semiconductor switch, such as a transistor.

[0068] exist Figure 2 In the example of FIG. 1 , the first disconnect switch 1012 is coupled to the pre-charge switch 1008 and in parallel with the resistor 1010. During pre-charging of the bulk capacitor 1002, the first disconnect switch 1012 is in an open or closed state, and the second disconnect switch 1014 is in an open or closed state.

[0069] Figure 3 Shown is a simplified example of a timing diagram of the signals obtained within the circuit 1000 according to the aforementioned first embodiment in the absence of a short circuit in the bulk capacitor 1002. In this figure, the signals are shown in a schematic manner with amplitudes that are not proportional to each other.

[0070] exist Figure 3 In the process, between time t1 and t4, the pulse control signal EN is applied to the control input terminal of the circuit 110 (with Figure 2 Since there is no short circuit of the bulk capacitor 1002, the pulse voltage across the primary winding 104 generates a non-zero pulse voltage across the first secondary winding 106 and the second secondary winding 108, which in turn generates a pulse current IS2 that circulates from the second secondary winding 108 through the bulk capacitor 1002 and increases the current sent to the control input of the pre-charge switch 1008 (corresponding to the gate of the transistor that forms the control switch 124 in the example). Figure 2 In the example, the gate of the thyristor forming the pre-charge switch 1008 corresponds to the amplitude of the control current IG1.

[0071] exist Figure 3In FIG. 1 , time t2 corresponds to the time when the thyristor forming pre-charge switch 1008 turns on, due to the fact that current IG1 reaches the value IGT that triggers the thyristor to turn on. Between times t1 and t2, the voltage VC1 across bulk capacitor 1002 increases due to the current drawn by second secondary winding 108. From time t2 onward, voltage VC1 increases more significantly due to the fact that pre-charge switch 1008 is in the on state and source 1004 is coupled to bulk capacitor 1002 via resistor 1010 and pre-charge switch 1008. From time t3 onward, once voltage VC1 exceeds the voltage supplied by second secondary winding 108, current IS2 becomes zero and bulk capacitor 1002 charges to reach the voltage value VBat of source 1004 at time t5. At time t4, when control signal EN applied to the control input of control switch 124 ceases due to the thyristor forming pre-charge switch 1008 being in the on state, current IG1 drops to zero. Starting from time t5 , the bulk capacitor 1002 is pre-charged and the source 1004 can be connected to the bus by turning on the first disconnect switch 1012 to limit the losses due to the resistor 1010 during steady-state operation of the device 100 .

[0072] Figure 4 Shown is a simplified example of a timing diagram of the signals obtained in the device 100 according to the aforementioned first embodiment in the presence of a short circuit in the bulk capacitor 1002. In this figure, the signals are shown in a schematic manner, with amplitudes that are not proportional to each other.

[0073] like Figure 3 As shown in FIG, the pulsed control signal EN is applied to the control input of circuit 110 between times t1 and t4. Due to the short circuit across bulk capacitor 1002, the voltage across bulk capacitor 1002 remains zero. Consequently, the voltage across second secondary winding 108 is also zero, which means that the voltage across first secondary winding 106 is also zero. Consequently, no control current is sent to the control input of pre-charge switch 1008, and pre-charge switch 1008 remains in the off state.

[0074] Below is about Figure 5 An example of a device 100 and a circuit 1000 according to a first variant of the first embodiment is described.

[0075] In this first variant, the device 100 and the circuit 1000 comprise the previously described Figure 2The device 100 according to this first variant further comprises a second Zener diode 128, the cathode of which is coupled to the cathode of the voltage rectifier diode 114 and to one of the electrodes of the power storage capacitor 116, and the anode of which is coupled to the control input of the pre-charging switch 1008, i.e. in the example described, to the gate of the thyristor forming this pre-charging switch 1008.

[0076] This first alternative embodiment can be advantageous in situations where the presence of a short circuit creates a load in parallel with the bulk capacitor 1002 and results in high leakage from the circuit 1000 (e.g., in the order of tens of ohms or less). In fact, in the presence of such a short circuit and without the second Zener diode 128, when a voltage is applied across the primary coil 104, a non-zero voltage can be obtained across each of the secondary coils 106, 108 and across the voltage rectifier diode 114. In this case, the amplitude of the voltage obtained across the secondary coils 106, 108 depends, among other things, on the amplitude of the current circulating through the load formed by the short circuit and on the ratio of the number of windings of the secondary coils 106, 108. A non-zero control current (e.g., a few mA) can then be sent to the control input of the pre-charge switch 1008, which can trigger it to be set to the conductive state, thereby triggering the pre-charging of the bulk capacitor 1002. When the device 100 includes a second Zener diode 128, such control current is blocked by the second Zener diode 128, thereby preventing the pre-charge switch 1008 from being set to the on state, thereby preventing the pre-charging of the bulk capacitor 1002, and the threshold of the second Zener diode 128 depends on the short-circuit leakage current level.

[0077] Previously about Figure 2 The different configurations described can be applied to this first variant of the first embodiment.

[0078] Below is about Figure 6 An example of a device 100 and a circuit 1000 according to a second variant of the first embodiment is described.

[0079] In this second variant, the device 100 and the circuit 1000 comprise the previously described Figure 2 All elements and components described herein, but transformer 102 includes at least one third secondary winding 130 having terminals configured to be coupled to a voltage measuring device ( Figure 6 ), for example, corresponding to a microcontroller. Figure 6 In the example of FIG, the second voltage rectifier diode 132 is coupled to one of the terminals of the third secondary winding 130 and blocks the voltage when the voltage of the third secondary winding 130 is negative, thereby enabling the voltage measuring device to measure only positive voltage.

[0080] This second variation can have the advantage of allowing the voltage of one of the secondary windings of the transformer 102 to be measured in an isolated manner without having to connect a voltage measuring device to the first secondary winding 106 and the second secondary winding 108. In a specific configuration, the third secondary winding 130 can have a winding number similar to that of the first secondary winding 106, which enables the voltage across the third secondary winding 130 to have a value similar to the voltage obtained across the first secondary winding 106. Therefore, a measurement of zero (or very low) voltage across the third secondary winding 130 can indicate the presence of a short circuit in the circuit 1000, particularly a short circuit across the bulk capacitor 1002.

[0081] Previously about Figure 2 The different configurations described can be applied to this second variant of the first embodiment. In addition, the first and second alternative embodiments described above can be combined with each other, in which case the device 100 comprises a second Zener diode 128 and a pulse transformer 102 comprising at least three secondary coils 106 , 108 and 130 .

[0082] The following is about Figure 7 An example of a device 100 and a circuit 1000 according to a second embodiment is described. In this second embodiment, the circuit 1000 may form part of or form a power converter.

[0083] In this second embodiment, the source 1004 comprises a totem pole type AC / DC voltage converter (AC input voltage at Figure 7 The voltage converter (referred to as VAC in the text) includes at least one first branch including two switching transistors 1016, 1018, for example of the MOS type, and at least one second branch including two switching thyristors 1020, 1022. The gates of the two thyristors 1020, 1022 are each coupled to a current limiting resistor 1024, 1026 and an optocoupler 1028, 1030 coupled in series with each other. In the example of the described embodiment, each component including 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 turned on during precharging of the bulk capacitor 1002.

[0084] Alternatively, transistors 1016 and 1018 may be of the IGBT (Insulated Gate Bipolar Transistor) type.

[0085] In this second embodiment, the transformer 102 includes, in addition to the first secondary winding 106 and the second secondary winding 108, a third secondary winding 130 having a first terminal 136 coupled to a second voltage rectifier diode 132. In the depicted example, the device 100 also includes a second power storage capacitor 134 coupled in parallel with the third secondary winding 130. Figure 7 In the example of , the first terminal 136 of the third secondary winding 130 is coupled via the second voltage rectifier diode 132 to one of the electrodes of the second power storage capacitor 134, which is here coupled in parallel with the assembly formed by the third secondary winding 130 and the second voltage rectifier diode 132. Figure 7 In the example, a cathode of the second voltage rectifier diode 132 is coupled to one of the electrodes of the second power storage capacitor 134 , and an anode of the second voltage rectifier diode 132 is coupled to the first terminal 136 of the third secondary winding 130 .

[0086] The first terminal 112 of the first secondary winding 106 is coupled to the control input of one of the pre-charge switches 1008 formed by the input electrode of the optocoupler 1028 via the first voltage rectifier diode 114, and the first terminal 136 of the third secondary winding 130 is coupled to the control input of another of the pre-charge switches 1008 formed by the input electrode of the optocoupler 1030 via the second voltage rectifier diode 132.

[0087] The operation of the device 100 and circuit 1000 according to the second embodiment is substantially similar to the operation previously described for the device 100 and circuit 1000 according to the first embodiment. When there is a short circuit in the bulk capacitor 1002, the voltage across each of the secondary windings 106, 108, 130 is equal to zero, and no control current is sent to the input electrodes of the optocouplers 1028, 1030. When there is no short circuit in the bulk capacitor 1002, the voltage across each of the secondary windings 106, 108, 130 is non-zero, and a non-zero control current is sent to the input electrodes of the optocouplers 1028, 1030, thereby triggering the turning on of the thyristors 1020, 1022 and precharging the bulk capacitor 1002 via the current flowing through the gates of the thyristors 1020, 1022.

[0088] As a variation of this second embodiment, as in the first variation of the first embodiment described above, the device 100 may include a Zener diode having its cathode coupled to the cathode of the voltage rectifier diodes 114, 132 and its anode coupled to the input electrode of each of the optocouplers 1028, 1030. As in the second variation of the first embodiment described above, the pulse transformer 102 may also include a fourth secondary winding, the terminals of which are configured to be coupled to a voltage measuring device.

[0089] The different configurations previously described with respect to the first embodiment may be applied to the device 100 and the circuit 1000 according to the second embodiment.

[0090] The following is about Figure 8 An example of a device 100 and a circuit 1000 according to a third embodiment is described.In this third embodiment, the circuit 1000 may form part of or form a power converter.

[0091] In this third embodiment, the source 1004 comprises an AC / DC voltage converter of the Boost PFC (“Power Factor Correction”) type with a hybrid bridge, which includes at least two switching diodes 138, 140 and two switching thyristors 1020, 1022. The gates of the two thyristors 1020, 1022 are each coupled to a current limiting resistor 1024, 1026 and an optocoupler 1028, 1030 coupled in series with one another. As in the second embodiment described above, each component 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 turned on during precharging of the bulk capacitor 1002.

[0092] As a variant, the switching diodes 138 , 140 can be replaced by thyristors.

[0093] A first terminal 112 of the first secondary winding 106 is coupled via a voltage rectifier diode 114 to a control input of a precharge switch 1008 formed by an input electrode of each of the optocouplers 1028, 1030. Thus, the current emitted by the first secondary winding 106 is intended to form the control current of the precharge switch 1008.

[0094] exist Figure 8In the example shown, circuit 1000 further includes a MOSFET-type transistor 142, such as transistor 124 of circuit 110. A pulsed control signal EN is applied to the gate of transistor 142. The source and drain electrodes of transistor 142 are coupled to the electrodes of bulk capacitor 1002 in a manner such that transistor 142 is coupled in parallel with bulk capacitor 1002. In addition, an inductor 144 is coupled to one of the electrodes of bulk capacitor 1002.

[0095] When transistor 142 is on, current flows through inductor 144, which accumulates energy. When transistor 142 is off, the energy stored in inductor 144 is sent to bulk capacitor 1002. By means of regulation via transistor 142, transistor 142 can be controlled in such a way that the supplied current is sinusoidal and in phase with the supplied voltage.

[0096] The operation of the device 100 and circuit 1000 according to the third embodiment is substantially similar to the operation previously described for the device 100 and circuit 1000 according to the first and second embodiments. When there is a short circuit in the bulk capacitor 1002, the voltage across each of the secondary windings 106, 108 is equal to zero, and no control current is sent to the input electrodes of the optocouplers 1028, 1030. When there is no short circuit in the bulk capacitor 1002, the voltage across each of the secondary windings 106, 108 is non-zero, and a non-zero control current is sent to the input electrodes of the optocouplers 1028, 1030, thereby setting the thyristors 1020, 1022 to the on state via current triggering through the gates of the thyristors 1020, 1022 and triggering pre-charging of the bulk capacitor 1002.

[0097] As a variation of this third embodiment, as in the first variation of the first embodiment described above, device 100 may include a Zener diode having its cathode coupled to the cathode of voltage rectifier diode 114 and its anode coupled to the input electrode of each of optocouplers 1028, 1030. As in the second variation of the first embodiment described above, pulse transformer 102 may further include a fourth secondary winding having terminals configured to be coupled to a voltage measuring device.

[0098] The different configurations previously described with respect to the first and second embodiments may be applied to the device 100 and the circuit 1000 according to the third embodiment.

[0099] The following is about Figure 9 An example of a device 100 and a circuit 1000 according to a fourth embodiment is described.In this fourth embodiment, the circuit 1000 may form part of or form a power converter.

[0100] In this fourth embodiment, the source 1004 comprises an AC / DC voltage converter of the Boost PFC type comprising at least a diode bridge 150 (in Figure 9 In FIG. 1 , the four switching diodes forming the diode bridge 150 are referenced by 138 , 140 , 146 and 148 .

[0101] In this fourth embodiment, the precharge switch 1008 configured to conduct during precharging of the bulk capacitor 1002 includes a thyristor whose gate forms a control input of the precharge switch 1008 coupled to a current limiting resistor 1024 and an optocoupler 1028 .

[0102] Other elements of the apparatus 100 and circuit 1000 are similar to those previously described with respect to the third embodiment.

[0103] The operation of the device 100 and circuit 1000 according to this fourth embodiment is substantially similar to the operation previously described for the device 100 and circuit 1000 according to the previous embodiments. In the presence of a short circuit in the bulk capacitor 1002, the voltage across each of the secondary windings 106, 108 is equal to zero, and no control current is sent to the input electrode of the optocoupler 1028. In the absence of a short circuit in the bulk capacitor 1002, the voltage across each of the secondary windings 106, 108 is non-zero, and a non-zero control current is sent to the input electrode of the optocoupler 1028, thereby triggering the thyristor forming the charging switch 1008 to be set to a conductive state via the current flowing through its gate and triggering pre-charging of the bulk capacitor 1002.

[0104] In all modes, examples and alternative embodiments, the thyristor(s) or SCR (“silicon controlled rectifier”) used to form the charging switch(es) 1008 may be replaced with other types of switches such as, for example, TRIACs, relays or transistors.

[0105] In the second, third and fourth embodiments described above, the source 1004 comprises an AC / DC converter. As a variant, the source 1004 may comprise a DC / DC converter or a transformer, such as a flyback converter.

[0106] As a variation of the examples of embodiments of the pre-charge control circuit 110 previously described in different embodiments, the circuit 110 may include a microcontroller and / or a DSP (digital signal processor) to control the primary coil 104 of the pulse transformer 102 .

[0107] The values ​​of the different elements previously described may differ from the previously mentioned examples, these values ​​varying in particular depending on the application and operating environment of the device 100 and the circuit 1000 .

[0108] The device 100 enables improved protection of the DC current circuit 1000 by using the pulse transformer 102 to detect a possible fault in the circuit 1000, such as a short circuit of the bulk capacitor 1002, due to one of the secondary windings of the transformer 102, and allowing or not allowing pre-charging of the bulk capacitor 1002 after the fault is detected or not detected and due to one or more other secondary windings of the transformer 102. Thus, the short circuit detection and pre-charge control functions are simultaneously implemented from the same pulse transformer.

[0109] For example, when a thyristor is used as a pre-charge switch, the device 100 can prevent the thyristor from turning on when, for example, there is a short circuit in the bulk capacitor 1002 or a fault, such as leakage, exists in the circuit 1000. When a relay is used as a pre-charge switch, the device 100 enables short circuit or fault detection in the circuit 1000 without having to close the relay to perform this detection.

[0110] The device 100 allows for fast detection of short circuit or leakage faults in the DC current circuit 1000. Additionally, the device 100 does not require circuitry dedicated only to the switching off of the pre-charge switch.

[0111] The device 100 may be used in particular in a battery management system (or BMS), in an electric vehicle or also in a power conversion structure, for example of the totem pole type, a hybrid bridge or the like.

[0112] For example, devices are intended for use in the automotive industry. The electrification of automotive vehicles is driving increasing levels of electronic content in vehicles. Examples of devices include thyristors, rectifiers, high-voltage transient voltage suppression diodes, and modules designed to be incorporated into such vehicles. Automated driving is also driving increasing electronic content in vehicles. For example, devices include high-voltage transient voltage suppression diodes, electromagnetic discharge protection, and common-mode filters to protect emerging complex electronic devices from electrical risks.

[0113] For example, the device can be used in the industrial sector. More specifically, for example, the device is intended for use in developing green energy or for electrification of infrastructure, such as in charging terminals or incorporating solar power. For example, the device is intended for implementation in power and energy circuits equipped with, for example, 800V or 1200V thyristors, ultrafast and silicon carbide 1200V diodes, transient voltage suppression diodes, and electromagnetic discharge protection. The device can also be used in data center and server implementations. For example, the device includes wide bandgap materials.

[0114] For example, the devices are intended for use in communications equipment or computers and peripherals. For example, the devices can be used in 5G infrastructure and dedicated data centers. For example, the devices include silicon carbide diodes, Schottky power transistors, electromagnetic discharge protection, and transient voltage suppression diodes. The devices can also be used in satellites, for example, including integrated passive devices for radio frequency applications.

[0115] The device can be used with any type of AC / DC or DC / DC converter.

[0116] The described solution can be used to control any type of pre-charging switch: thyristor, MOSFET, relay, IGBT, etc.

[0117] Various embodiments and variations have been described. Those skilled in the art will appreciate that certain features of these various embodiments and variations may be combined, and those skilled in the art will recognize other variations.

[0118] Finally, based on the functional indications given above, the actual implementation of the described embodiments and variants is within the capabilities of a person skilled in the art.

Claims

1. A device for controlling pre-charging of a bulk capacitor and for detecting a fault in a DC current circuit, the DC current circuit comprising the bulk capacitor, at least one DC voltage source, and at least a first pre-charging switch coupled to an electrode of the bulk capacitor, the device comprising: A pulse transformer having a primary coil and at least a first secondary coil and a second secondary coil; as well as a circuit for controlling pre-charging of the bulk capacitor, the circuit being coupled to the primary winding of the pulse transformer; wherein the first secondary winding of the pulse transformer comprises a first terminal, and the first terminal is configured to be coupled to a control input of the first pre-charging switch; and Wherein, the second secondary coil of the pulse transformer is configured to be coupled in parallel with the large-capacity capacitor.

2. The apparatus of claim 1, further comprising at least a first power storage capacitor coupled in parallel with the first secondary winding of the pulse transformer.

3. The apparatus according to claim 1, further comprising: at least a first voltage rectifier diode having an anode coupled to a first terminal of a first secondary winding of the pulse transformer; and / or at least a first current limiting resistor, an electrode of the first current limiting resistor being configured to be coupled to a control input of the first pre-charging switch.

4. The apparatus of claim 3, further comprising at least a second Zener diode having a cathode coupled to a cathode of the first voltage rectifier diode and an anode of the second Zener diode configured to be coupled to a control input of the first pre-charge switch.

5. The apparatus of claim 1, further comprising at least a second protection diode coupled in series with the second secondary winding of the pulse transformer.

6. The apparatus according to claim 1, wherein The circuit for controlling the pre-charging of the bulk capacitor comprises at least: a third diode having a cathode coupled to the first terminal of the primary winding of the pulse transformer; a first Zener diode having an anode coupled to the anode of the third diode and a cathode coupled to the second terminal of the primary winding of the pulse transformer; as well as A control switch is coupled to the second terminal of the primary winding of the pulse transformer.

7. The apparatus according to claim 1, wherein The second terminal of the first secondary winding of the pulse transformer is coupled to one of the one or more terminals of the second secondary winding of the pulse transformer.

8. The apparatus according to claim 1, wherein The pulse transformer includes at least a third secondary winding, a terminal of the third secondary winding being configured to be coupled to a voltage measurement device or a control input of a second pre-charge switch.

9. A DC current circuit comprising: DC voltage source; a bus comprising at least two conductive elements, each conductive element coupled to one of the one or more terminals of the DC voltage source; a capacitive element forming a bulk capacitor, each electrode of the bulk capacitor coupled to one of the two conductive elements of the bus; a first pre-charge switch coupled to an electrode of the bulk capacitor; as well as Device for controlling the pre-charging of the bulk capacitor and for detecting a fault in the DC current circuit, comprising: a pulse transformer having a primary coil and at least a first secondary coil and a second secondary coil; and a circuit for controlling pre-charging of the bulk capacitor, the circuit being coupled to the primary winding of the pulse transformer; wherein the first secondary winding of the pulse transformer comprises a first terminal, and the first terminal is configured to be coupled to a control input of the first pre-charging switch; and Wherein, the second secondary coil of the pulse transformer is configured to be coupled in parallel with the large-capacity capacitor.

10. The DC current circuit according to claim 9, wherein: The DC voltage source comprises at least a battery.

11. The DC current circuit according to claim 10, wherein: The first pre-charging switch includes at least a first thyristor, and a control input terminal of the first pre-charging switch corresponds to a gate of the first thyristor, and further includes: a second current limiting resistor coupled in series with the first thyristor; and A first disconnect switch and a second disconnect switch, each disconnect switch coupled between one of the one or more terminals of the DC voltage source and one of the electrodes of the bulk capacitor, at least one of the first disconnect switch and the second disconnect switch comprising a relay.

12. The DC current circuit according to claim 11, wherein One of the first disconnect switch and the second disconnect switch is coupled in parallel with the first thyristor and with the second current limiting resistor.

13. The DC current circuit according to claim 9, wherein: The DC voltage source includes a totem-pole type AC / DC voltage converter, the totem-pole type AC / DC voltage converter including at least two switching transistors and at least two switching thyristors, the gates of the switching transistors and the switching thyristors being each coupled to a third current limiting resistor and an optocoupler coupled in series with each other and forming a first pre-charge switch and a second pre-charge switch; Wherein, the pulse transformer of the device comprises at least a third secondary coil; wherein a first terminal of a first secondary winding of a pulse transformer of the apparatus is coupled to an input electrode of one of the optical couplers; and The first terminal of the third secondary coil of the pulse transformer of the device is coupled to an input electrode of another optocoupler among the optocouplers.

14. The DC current circuit according to claim 9, wherein: The DC voltage source comprises an AC / DC voltage converter of the Boost PFC type having a hybrid bridge, the voltage converter comprising at least two switching diodes and at least two switching thyristors or at least four switching thyristors, the gate of each switching thyristor being coupled to a third current limiting resistor and an optocoupler coupled in series with each other and forming a first pre-charging switch and a second pre-charging switch; as well as Wherein, a first terminal of a first secondary coil of a pulse transformer of the apparatus is coupled to an input electrode of each of the optocouplers.

15. The DC current circuit according to claim 9, wherein: The DC voltage source comprises an AC / DC voltage converter of the Boost PFC type having a diode bridge; and The first pre-charging switch at least includes a first thyristor, a third current limiting resistor, and an optical coupler coupled to each other in series.

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