Device and method for protecting an item of equipment supplied with power by a high-voltage DC bus

Abstract

The invention relates to a device (1) for protecting an item of equipment (E) to be supplied with power by a high-voltage DC bus (B), characterized by an inhibition circuit (15) intended to disconnect the high-voltage DC power source (S) and having a trigger (153) that is configured, in response to an activation signal (S1), to adopt a position (P1) that causes a signal (S2) commanding stoppage of the source (S) to be sent, the trigger (153) being connected to a first manual command means (154) that when actuated causes the trigger (153) to change from the position (P1) to a second position that does not cause the signal (S2) to be sent, and an abnormal voltage (VB) detection circuit (13), which is configured to send the signal (S1) when a voltage (VB) greater than a prescribed threshold (VMAX), which is greater than the nominal DC supply voltage value (HVDCNOM), is detected.

Description

[0001] DESCRIPTION

[0002] TITLE: Device and method for protecting equipment powered by a high-voltage direct current bus

[0003] The invention relates to a device and a method for protecting equipment that is to be powered by a high-voltage direct current bus.

[0004] The field of the invention relates to any equipment that must be powered by a DC voltage source via the bus.

[0005] Due to the increasing voltages applied to equipment, particularly in the aerospace industry where equipment electrification is becoming increasingly common, the energies involved quickly become very significant (the stored energy being proportional to the square of the voltage). In the event of an unexpected overvoltage during testing, for example resulting from a malfunction of the equipment or the system in which the equipment is integrated, it is imperative to shut down the power source.

[0006] During equipment testing campaigns, in the event of a problem (for example, a hardware failure) or in the event of incorrect handling of the source or load connected to the equipment, the high DC voltage of the bus supplying the equipment may increase rapidly and uncontrollably due to the flow of significant energy.

[0007] The prior art includes sources providing high DC voltage on the bus, these sources having a disconnecting device from the bus in case of overvoltage of the latter.

[0008] But this disconnection is usually slow, on the order of a few hundred milliseconds, which does not allow for effective protection of the equipment which has internal components very sensitive to overvoltages, components which can be damaged in a few milliseconds if no protection is triggered due to the energy levels involved.

[0009] Excess energy is dangerous for the equipment, as it is not designed to withstand it in scenarios resulting from a failure or malfunction of its environment, even less so during tests taking place at the beginning of its development cycle, i.e. at a time when the equipment may still have design weaknesses that will later be resolved.

[0010] An objective of the invention is to obtain a device and a method for protecting equipment to be powered by a high-voltage DC bus during its operation, which overcomes the drawbacks mentioned above and effectively protects the equipment. To this end, a first object of the invention is a device for protecting equipment to be powered by a high-voltage DC bus, the protection device comprising a first connection terminal to a first conductor of the bus and a second connection terminal to a second conductor of the bus, the first and second conductors being intended to connect the equipment to a high-voltage DC power supply intended to apply a high-voltage DC supply voltage between them to the equipment having a nominal value of DC supply voltage, characterized in that the protection device further comprises: an inhibition circuit,intended to cut off the high-voltage DC power supply, the inhibition circuit comprising an activation input, at least one control output of the high-voltage DC power supply, a trip unit and a first manual control disposed on an external surface of the protective device, the trip unit being configured to assume and maintain, in response to a prescribed activation signal on the activation input, a first position, which causes a control signal to be sent to stop the high-voltage DC power supply on the at least one control output, the trip unit being connected to the first manual control,which is configured such that actuation of the first manual control moves the trigger from the first position to a second position without causing the shutdown control signal of the high-voltage DC power supply to be sent to at least one control output, an abnormal voltage detection circuit, which is connected between the first terminal and the second terminal, which has an activation output connected to the activation input and which is configured to send the prescribed activation signal to the activation output when a voltage exceeding a first prescribed DC voltage threshold, greater than the nominal DC supply voltage of the high-voltage DC power supply, is detected between the first terminal and the second terminal.

[0011] Thanks to the invention, the occurrence of an overvoltage on the bus relative to the nominal DC supply voltage is quickly detected by the circuit, triggering the inhibition of the source and thus stopping the external power supply to the equipment as quickly as possible. The trigger according to the invention locks the device in the first position for sending the command signal to stop the high DC supply voltage, thereby eliminating the overvoltage on the bus and consequently on the equipment. The device according to the invention ensures that the trigger can only be reset to the second position manually by the first command, preventing the device from automatically returning to the second position and ensuring that the device remains in the first position after the source is shut down, thus preventing the source from being restarted and causing further damage to the equipment.According to one embodiment of the invention, the protection device includes a power bypass circuit connected between the first terminal and the second terminal. This power bypass circuit diverts the temporary energy surge, due to an overvoltage present on the bus, away from the equipment, thus providing greater protection for the equipment.

[0012] According to one embodiment of the invention, the power bypass circuit comprises at least one first resistor and at least one power switch, which are in series between the first terminal and the second terminal, the power switch having a control input connected to the activation output and being configured to take a connection state of the first resistor between the first terminal and the second terminal in the case where the prescribed activation signal is present on the control input and to take a disconnection state of the first resistor between the first terminal and the second terminal in the case where the prescribed activation signal is absent on the control input.

[0013] According to one embodiment of the invention, the power switch comprises at least one transistor.

[0014] According to one embodiment of the invention, the abnormal voltage detection circuit comprises a resistive voltage divider bridge having at least a second resistor and at least a third resistor, which are connected in series between the first terminal and the second terminal, and a voltage comparator, which is connected in parallel with the at least a third resistor and which is configured to compare the voltage in parallel with the at least a third resistor to a prescribed reference voltage, equal to a prescribed divisor factor multiplied by the first prescribed DC voltage threshold, the prescribed divisor factor being equal to the resistive value of the at least a third resistor, divided by the sum of the resistive value of the at least a second resistor and the resistive value of the at least a third resistor, the voltage comparator being configured to send the prescribed activation signal on the activation output,in the event that the voltage in parallel with at least a third resistor is greater than the prescribed reference voltage.

[0015] According to one embodiment of the invention, the trigger comprises a bistable relay having only the first position and the second position as stable states.

[0016] According to one embodiment of the invention, the protection device includes a power supply circuit, configured to supply power from the first terminal and the second terminal to the abnormal voltage detection circuit and / or the inhibition circuit.

[0017] According to one embodiment of the invention, the protection device includes a test circuit for sending the activation signal prescribed by the abnormal voltage detection circuit, the test circuit comprising a second manual control disposed on the outer surface of the protection device and at least one external indicator disposed on the outer surface of the protection device, the external indicator being configured to send a first voltage presence signal to the outside when a voltage less than or equal to the first prescribed DC voltage threshold is present between the first terminal and the second terminal, the second manual control being configured such that actuation of the second manual control causes a test of sending the activation signal prescribed by the abnormal voltage detection circuit,The transmission by the external indicator of the first voltage presence signal to the outside in the event that the prescribed activation signal has not been sent by the abnormal voltage detection circuit, and the absence of transmission by the external indicator of the first voltage presence signal to the outside in the event that the prescribed activation signal has been sent by the abnormal voltage detection circuit.

[0018] According to one embodiment of the invention, the inhibition circuit includes at least one other control output for a load intended to be connected to the equipment, the first position of the trigger causing the sending of a control signal to stop the load on the other control output.

[0019] A second object of the invention is a method for protecting equipment to be powered by a high-voltage DC bus using the protection device as described above, the first terminal of which is connected to the first conductor of the bus and the second terminal of which is connected to the second conductor of the bus, the first and second conductors connecting the equipment to a high-voltage DC power supply intended to apply between them a high-voltage DC supply to the equipment having a nominal value of DC supply voltage, characterized in that the method further comprises the following steps: actuation of the first manual control to move the trigger from the first position to the second position without causing the sending of the stop control signal of the high-voltage DC power supply to at least one control output,The voltage between the first and second terminals is measured by the abnormal voltage detection circuit, which sends the prescribed activation signal to the activation output connected to the activation input. If the voltage between the first and second terminals exceeds the first prescribed DC voltage threshold, and is greater than the nominal DC voltage value of the high-voltage DC supply, then, in response to the presence of the prescribed activation signal at the activation input, the trigger switches from the second position to the first position. This causes the shutdown control signal of the high-voltage DC supply to be sent to at least one control output connected to the high-voltage DC supply.

[0020] The invention will be better understood upon reading the following description, given solely as a non-limiting example with reference to the figures below of the attached drawings.

[0021] [Fig. 1] represents an electrical diagram of equipment on which the protection device and protection method according to the invention can be used.

[0022] [Fig. 2] represents an electrical diagram of the protection device according to the invention in a first triggered position of stopping the high voltage DC supply source.

[0023] [Fig. 3] represents an electrical diagram of the protection device according to the invention in a second position triggered manually so as not to cause the shutdown of the high voltage DC power supply source.

[0024] [Fig. 4] represents an electrical diagram of a voltage detection circuit of the protection device according to an embodiment of the invention.

[0025] [Fig. 5] represents a flowchart of a protection process according to an embodiment of the invention.

[0026] An example of a protection device 1 according to embodiments of the invention is described in more detail below with reference to Figures 1 to 4, and an example of a protection method having the steps mentioned below according to embodiments of the invention is described with reference to Figure 5. In Figures 1 to 4, electrical nodes are symbolically represented by circular dots, while the intersections between lines, which are not circular dots, are not nodes.

[0027] In Figure 1, a device E is powered by a high-voltage DC bus B. The high-voltage DC bus B has a first conductor B1 and a second conductor B2, which connect a high-voltage DC power supply S to the device E and carry the high-voltage DC supply, provided by the source S, to the device E, provided that the source S is not switched off. The high-voltage DC power supply S applies the high-voltage DC supply, HVDC, between the first conductor B1 and the second conductor B2 to the device E, having a prescribed nominal value HVDCNOM of DC supply voltage, provided that the source S is not switched off. The source S is controllable from the outside and therefore has one (or more) input 1520 for receiving a stop command, suitable for connection to the outside of the source S.The prescribed nominal value HVDCNOM of the DC supply voltage is the value of the high DC supply voltage HVDC supplied by the source S on the bus B in the absence of abnormal voltage and in the absence of overvoltage on the bus B. The equipment E can be connected to a load Z.

[0028] Equipment E can be, for example, electrical power equipment, an actuator, an inverter, a motor, an electric motor intended for use in an aircraft, or other similar items. Equipment E and / or the load Z can be part of, for example, a test bench for one of these components, this test bench being used for the development of that component.

[0029] The protective device 1 is intended to be connected in parallel with the equipment E on the bus B. The protective device 1 has a first terminal 11 intended to be connected to the first conductor B1 of the bus B and a second terminal 12 intended to be connected to the second conductor B2 of the bus B. The voltage present between the second terminal 12 and the first terminal 11 is called the voltage V B .

[0030] In Figure 2, the protection device 1 includes an abnormal voltage detection circuit 13 on bus B, this circuit 13 being connected between the first terminal 11 and the second terminal 12. The abnormal voltage detection circuit 13 is configured to send, during the first step El, the prescribed activation signal SI on the activation output 131 of the circuit 13, when a voltage VB exceeding a first prescribed threshold VMAX of DC voltage, greater than the nominal value HVDCNOM of the high DC supply voltage HVDC (in the case of an overvoltage VB), is detected by the circuit 13 between the first terminal 11 and the second terminal 12. The abnormal voltage detection circuit 13 allows the voltage VB to be measured between the first terminal 11 and the second terminal 12.The abnormal voltage VB detection circuit 13 includes a circuit 130 for comparing the voltage VB present between the first terminal 11 and the second terminal 12 to the first prescribed threshold VMAX of DC voltage, to send during the first step El the prescribed activation signal SI on the activation output 131 in the case where the voltage VB present between the first terminal 11 and the second terminal 12 is greater than the first prescribed threshold VMA of DC voltage, and not to send the prescribed activation signal SI on the activation output 131 in the case where the voltage VB present between the first terminal 11 and the second terminal 12 is less than or equal to the first prescribed threshold VMAX of DC voltage.

[0031] The VB abnormal voltage detection circuit 13 can be made up of analog components, which allows for a very short response time.

[0032] According to one embodiment of the invention, the comparison circuit 130 of the abnormal voltage detection circuit 13 VB is configured to send, during the first step El, the prescribed activation signal SI on the activation output 131, in the case where the voltage VB present between the first terminal 11 and the second terminal 12 is greater than the first prescribed threshold VMAX of DC voltage, and not to send the prescribed activation signal SI on the activation output 131 when both the voltage VB present between the first terminal 11 and the second terminal 12 is less than or equal to the first prescribed threshold VMAX of DC voltage.

[0033] The 130 comparator circuit can be made up of one or more analog components, which allows for a very short response time.

[0034] The protection device 1 includes an inhibition circuit 15, designed to disconnect the high-voltage DC power supply S when certain conditions verified by the inhibition circuit 15 are met. The inhibition circuit 15 comprises an activation input 151, one (or more) control outputs 152 for the high-voltage DC power supply S, a trip unit 153, and a first manual control 154 located on an external surface 18 of the protection device 1. The activation output 131 of the abnormal voltage detection circuit 13 is connected to the activation input 151 of the inhibition circuit 15. The control output 152 may consist of two conductors. The inhibition circuit 15 may consist of one or more analog components.

[0035] During the first step El, the presence of the prescribed activation signal SI on the activation input 151 causes the trigger 153 to switch to and then hold in a first PI position (Figure 2). This triggers the sending of a stop command signal S2 to the control output 152, which sends a stop command signal S2 to the control output 152. The control output 152 is connected to the stop command input(s) 1520. The stop command signal S2 from the control output 152 causes the high-voltage DC power supply S to shut down during the first step El, thus ceasing to supply the high-voltage DC power supply on the bus B between the first conductor B1 and the second conductor B2.The shutdown of the high-voltage DC power supply source S can be achieved by disconnecting the source S from the first conductor B1 and the second conductor B2 of bus B. This is accomplished using internal switches (e.g., contactors or similar) within the source, which are activated by the presence of the shutdown command signal S2 at the shutdown command input(s) 1520. This protects equipment E from overvoltages. The S2 control signal at the control output 152 disconnects the high-voltage DC power supply source S, thus stopping the power supply to equipment E.

[0036] In the case where the abnormal voltage detection circuit 13 and the inhibition circuit 15 are made up of analog components, the control signal S2 on the control output 152 can thus be triggered 20 milliseconds after the appearance of the overvoltage between the first terminal 11 and the second terminal 12. This gain in reactivity is due to the fact that each analog component has a very short response time, which can be on the order of a hundred nanoseconds.

[0037] According to one embodiment of the invention, the stop control signal S2 can be an open-circuit or high-impedance signal on the control output 152. According to another embodiment of the invention, the stop control signal S2 can be a closed-circuit, short-circuit, or low-impedance signal on the control output 152.

[0038] In Figures 2 and 3, the trigger 153 is connected to the first manual control 154. The actuation of the first manual control 154 by a user during the second step E2 following the first step El causes the trigger 153 to move from the first position PI to the second position P2, known as the reset position, (Figure 3), not causing the sending of the stop command signal S2 of the high voltage DC supply source S on the control output 152 (or causing the sending of the start command signal S3 of the high voltage DC supply source S on the control output 152).The absence of the S2 control signal to stop the high voltage DC supply source S on the control output 152 or the presence of the S3 control signal to start the high voltage DC supply source S on the control output 152 causes the high voltage DC supply source S to start during the second stage E2, which then supplies the high voltage DC HVDC supply on the bus B between the first conductor B1 and the second conductor B2.

[0039] The high-voltage DC power supply S can only be restarted manually by manually activating the first manual control 154 to move the trigger 153 from the first position PI to the second position P2. This prevents the protection device 1 from returning to the second position P2 on its own following the reappearance of high voltage HVDC on bus B, which could be unintentional and unwanted. This prevents damage to the equipment E if a residual voltage is still present on bus B.

[0040] Between the first step E1 and the second step E2, the possible absence of the prescribed activation signal SI on the activation input F 151 keeps the trigger 153 in the first position PI (Figure 2), which causes the shutdown control signal S2 of the high-voltage DC power supply S to be sent to the control output 152. The trigger 153 therefore retains a memory of the last activation signal SI present on the activation input 151 to maintain the trigger 153 in the first position PI (Figure 2), which causes the shutdown control signal S2 of the high-voltage DC power supply S to be sent to the control output 152, until the first manual control 154 is actuation by a user during the second step E2 causes the trigger 153 to move from the first position PI to the second position P2 reset (Figure 3).This memory can be mechanical or electromechanical, as for example in the case of a relay described below.

[0041] Indeed, once the S2 control signal for stopping the high-voltage DC power supply source S is present at the control output 152 during the first step El, the high-voltage DC power supply source S is stopped and no longer supplies the high-voltage DC power supply on the bus B between the first conductor B1 and the second conductor B2. The voltage VB between the first terminal 11 and the second terminal 12 can then fall below the first threshold VMA, which in this case means that the abnormal voltage VB detection circuit 13 will only detect that the voltage VB between the first terminal 11 and the second terminal 12 is above the first threshold VMAX, and will no longer supply the prescribed activation signal SI on the activation input 151.In this case, the trigger 153 is held in the first position PI until the actuation of the first manual control 154 by a user during the second step E2 causes the trigger 153 to move from the first position PI to the second reset position P2 (Figure 3). This allows the stop command signal S2 of the high-voltage DC power supply S to be stored, even after all power on the bus B has been lost.

[0042] The first step El is preceded by an initial step EO during the installation of the protection device 1 on the bus B and on the source S. During the initial step EO, a user operates the first manual control 154 to put the trigger 153 in the second position P2 (figure 3), not causing the sending of the stop command signal S2 of the high voltage DC supply source S on the control output 152 (or causing the sending of the start command signal S3 of the high voltage DC supply source S on the control output 152).The absence of the S2 control signal to stop the high-voltage DC power supply S on the control output 152, or the presence of the S3 control signal to start the high-voltage DC power supply S on the control output 152, causes the high-voltage DC power supply S to start during the initial step EO. This then supplies the high-voltage DC power supply on the bus B between the first conductor B1 and the second conductor B2. The initial step EO is therefore analogous to the second step E2.

[0043] According to one embodiment of the invention, the first manual control 154 only allows the trigger 153 to be moved from the first position PI to the second position P2 of resetting, and not from the second position P2 of resetting to the first position PL

[0044] The first manual control 154 may be in the form of a push button or a lever or a handle or other, and is accessible on the outer surface 18 of the protective device 1 by a user.

[0045] According to one embodiment of the invention, the first manual control 154 is in a first arrangement DI with respect to the outer surface 18 in the first position PI of the trigger 153, and is in a second arrangement D2 with respect to the outer surface 18 in the second position P2 of the trigger 153, this second arrangement D2 being different from the first arrangement D1.

[0046] According to one embodiment of the invention, the trigger 153 is bistable, that is, it has only the first position PI and the second position P2 (reset) as stable states. The trigger 153 may be or include a bistable (electromechanical) relay 1530 or a bistable (electromechanical) contactor 1530. The fact that the trigger 153 or relay 1530 is bistable allows, once the prescribed activation signal SI is present at the activation input 151 and has triggered the stop control signal S2 of the high-voltage DC supply source S at the control output 152, for this activation signal SI present at the activation input 151 to maintain the trigger 153 or relay 1530 in the first position PI (Figure 2), as indicated above.

[0047] The 1530 bistable relay has its input circuit connected to the activation input 151, for example, via an isolator. Thus, the 1530 bistable relay can be controlled by the isolator in the inhibit circuit 15. This isolator isolates the abnormal voltage detection circuit 13 (VB), which is referenced to the high-voltage DC bus B, from the source S to be controlled, thereby protecting both the source and the users.

[0048] The bistable relay 1530 has its input circuit connected to the activation output 131. The moving part of the bistable relay 1530 is connected to the first manual control 154, so that the moving part can be actuated from the first position P1 to the second position P2 by the first manual control 154.

[0049] According to one embodiment of the invention, the protection device 1 includes a power bypass circuit 14 connected between the first terminal 11 and the second terminal 12. This power bypass circuit 14 allows the excess energy stored on bus B to be discharged and dissipated once bus B experiences an overvoltage VB exceeding the first threshold VMAX. The power bypass circuit 14 allows the excess energy stored on bus B to be discharged and dissipated once the presence of the stop signal S2 of the high-voltage DC power supply S on the control output 152 has stopped the high-voltage DC power supply S during the first step El. Indeed, this excess energy can prove dangerous and destructive to the equipment E or to a user who might attempt to intervene in the operation.This allows residual energy to be diverted to a circuit other than the equipment itself, as the equipment is not designed to withstand such a temporary overload. This protects equipment E from unwanted overvoltages on bus B, which could damage the equipment, and dissipates the excess energy in the dedicated power bypass circuit 14, preventing it from reaching and damaging the equipment.

[0050] According to one embodiment of the invention, the power bypass circuit 14 comprises one (or more) first power electrical resistor 141 and one (or more) power switch 142, which are connected in series between the first terminal 11 and the second terminal 12. The control input 143 of the power switch 142 is connected to the activation output 131.

[0051] The power switch 142 enters a connected state of the first resistor 141 between the first terminal 11 and the second terminal 12 when the prescribed activation signal SI is present at the control input 143. In this connected state, the energy present between the first terminal 11 and the second terminal 12 is dissipated in the first resistor(s) 141.

[0052] The power switch 142 takes a disconnect state of the first resistor 141 between the first terminal 11 and the second terminal 12, in the case where the prescribed activation SI signal is absent on the control input 143.

[0053] The power switch 142 can be made of one or more analog components, allowing for a very short response time. The power switch 142 can be semiconductor. According to one embodiment of the invention, the power switch 142 comprises one or more transistors 144, such as one or more IGBT (insulated-gate bipolar transistor) transistors, or one or more thyristors, or the like. The resistor(s) 141 is / are made of one or more analog components. The power bypass circuit 14 can thus be triggered (switching the power switch 142 to the conducting state) on the order of one millisecond after the prescribed activation signal SI is sent to the control input 143.

[0054] According to one embodiment of the invention, the bypass circuit 14 is activated at the same time as the stop control signal S2 is sent to the control output 152 of the source S. As this circuit 14 can be faster to trigger (on the order of 1ms as indicated above) than the source S, there can be a short period of time during which the source S is still delivering power and the bypass circuit 14 is active.

[0055] According to one embodiment of the invention, shown in Figure 4, the abnormal voltage VB detection circuit 13 comprises, as a voltage VB comparison circuit 130, a resistive voltage divider 132 and a voltage comparator 135. The resistive voltage divider 132 comprises one (or more) second electrical resistor(s) 133 and one (or more) third electrical resistor(s) 134, which are connected in series between the first terminal 11 and the second terminal 12. The abnormal voltage VB detection circuit 13 comprises a voltage comparator 135, which is connected in parallel with the third resistor(s) 134. The voltage comparator 135 comprises a comparison input 137 connected to the node 139 linking the second electrical resistor 133 to the third electrical resistor 134.The third electrical resistor(s) 134 is connected between node 139 and a reference input 138 of the voltage comparator 135, this reference input 138 being connected to the second terminal 12. The second electrical resistor(s) 133 is connected between node 139 and the first terminal 11. During the first step E1, the voltage comparator 135 compares the voltage V3, which is between the comparator input 137 and the reference input 138, to a prescribed reference voltage VREF, which is present between an input 136 of the comparator 135 and the reference input 138. The prescribed reference voltage VREF is equal to a prescribed divisor multiplied by the first prescribed threshold DC voltage VMAX. This prescribed divisor coefficient is equal to FL / (FL+FL), where R3 is the resistive value of the third resistance (or resistances) 134 and R2 is the resistive value of the second resistance (or resistances) 133.The voltage comparator 135 generates the prescribed activation signal SI on the activation output 131 when the voltage V3 in parallel with the third resistor(s) 134 is greater than the prescribed reference voltage VREF. The resistor(s) 133 is / are formed from one or more analog components. The resistor(s) 134 is / are formed from one or more analog components.

[0056] According to one embodiment of the invention, 0 < FL / (FL+FL) < 0.1. In particular, 0 < LI Î+ Ù < 0.01.

[0057] According to one embodiment of the invention, the nominal value HVDCNOM of the DC supply voltage is greater than or equal to 500 V and less than or equal to 1000 V. Of course, the nominal value HVDCNOM of the DC supply voltage could be outside this range.

[0058] According to one embodiment of the invention, the nominal value HVDCNOM of the DC supply voltage can be greater than or equal to 700 V and less than or equal to 800 V. Of course, the nominal value HVDCNOM of the DC supply voltage could be outside this range.

[0059] According to one embodiment of the invention, the first prescribed threshold VMAX of the DC voltage is greater than or equal to 500 V and less than or equal to 1200 V, while being greater than the nominal value HVDCNOM of the DC supply voltage as indicated above. Of course, the first prescribed threshold VMAX of the DC voltage could be outside this range, while still being greater than the nominal value HVDCNOM of the DC supply voltage as indicated above.

[0060] According to one embodiment of the invention, the protection device 1 comprises a power supply circuit 17, configured to supply power from the first terminal 11 and the second terminal 12 to the abnormal voltage detection circuit 13 and / or the inhibition circuit 15. The power supply circuit 17 thus supplies power to the abnormal voltage detection circuit 13 and / or the inhibition circuit 15 from the high DC supply voltage HVDC (or the nominal DC supply voltage HVDCNOM) present between the first terminal 11 and the second terminal 12. The power supply circuit 17 comprises an input portion 171 connected to the first terminal 11 and the second terminal 12, and an output portion 172 connected to the abnormal voltage detection circuit 13 and / or the inhibition circuit 15.The input section 171 includes a step-down circuit configured to reduce the high DC supply voltage (HVDC) (or the nominal value of the HVDCNOM DC supply voltage) present between the first terminal 11 and the second terminal 12 to a DC supply voltage VAL. This voltage is lower than the high DC supply voltage (HVDC) (or the nominal value of the HVDCNOM DC supply voltage) and is present at the output section 172 for supply to the abnormal voltage detection circuit 13 (VB) and / or the inhibiting circuit 15. The power supply circuit 17 allows the protection device 1 to be self-powered for ease of use. Such a power supply circuit can be particularly advantageous during relatively long test campaigns.The power supply circuit 17 allows the protection device 1 to be powered directly by bus B and thus remain functional as long as the bus B voltage has not completely disappeared. The power supply circuit 17 can consist of one or more analog components.

[0061] According to one embodiment of the invention, 0 < VAL / HVDC < 0.1. In particular, 0 < VAL / HVDC < 0.01.

[0062] According to one embodiment of the invention, 0 < VAL / HVDCNOM < 0.1. In particular, 0 < VAL / HVDCNOM < 0.01.

[0063] For example, VAL < 20 V. For example, VAL = 15 V. Of course, VAL can have other values ​​than this example.

[0064] According to one embodiment of the invention, the protection device 1 includes a test circuit 16 for verifying the functionality of the abnormal voltage detection circuit 13, i.e., for testing the transmission of the activation signal SI prescribed by the abnormal voltage detection circuit 13. The test circuit 16 includes a second manual control 161 located on the outer surface 18 of the protection device 1 and one (or more) external indicator 162 for the presence of high DC voltage (HVDC) supply between the first terminal 11 and the second terminal 12, this (or these) indicator 162 being located on the outer surface 18 of the protection device 1. The external indicator 162 is (or is) visual and / or audible.The external indicator 162 is configured to send a first voltage presence signal to the outside (which may be sending a first light signal to the outside and / or sending a first audible signal to the outside), when a voltage VB less than or equal to the first prescribed threshold VMAX of DC voltage (and greater than another threshold less than the nominal value HVDCNOM of DC supply voltage) is present between the first terminal 11 and the second terminal 12.The outdoor indicator 162 is configured not to send the first voltage presence signal outside (or to send another voltage absence signal, which may be sending a second light signal different from the first light signal outside and / or sending a second audible signal different from the first audible signal outside), when a voltage VB less than or equal to the first prescribed threshold VMAX of DC voltage (and greater than another threshold less than the nominal value HVDCNOM of DC supply voltage) is present between the first terminal 11 and the second terminal 12.

[0065] The actuation of the second manual control 161 by a user during the third step E3, which is subsequent to the initial step E0 or subsequent to the first step El or subsequent to the second step E2, causes the test circuit 16 to perform a test of sending the activation signal SI prescribed by the abnormal voltage detection circuit 13 VB.In the event of correct operation of the abnormal voltage detection circuit 13 VB, this functional test causes the prescribed activation signal SI to be sent to the activation output 131, which causes the control signal S2 to be sent by the trigger 153 to stop the high voltage DC supply source S on the control output 152, the connection state of the power bypass circuit 14, the interruption of the high voltage DC supply source S, and the absence of the first voltage presence signal being sent by the external indicator 162 to the outside, because there is no longer any voltage applied by the source S having been cut off.

[0066] In the event of an incorrect operation of the abnormal voltage detection circuit 13 (VB), this functional test does not trigger the transmission of the prescribed activation signal SI to the activation output 131. Consequently, the trigger 153 does not send the shutdown control signal S2 to the control output 152 of the high-voltage DC power supply source S, nor does it activate the power bypass circuit 14, nor does it disconnect the high-voltage DC power supply source S. In this case, because the voltage applied by source S has not been disconnected, the external indicator 162 continues to send the initial voltage presence signal externally.

[0067] Therefore, during this functional test, the second manual control 161 is configured so that its activation causes the external indicator 162 to send the first voltage presence signal externally if the prescribed activation signal SI has not been sent by the abnormal voltage detection circuit 13 (VB). This scenario corresponds to the incorrect operation of the abnormal voltage detection circuit 13 during the test. The user thus realizes, by the fact that the external indicator 162 still sends the first voltage presence signal externally, that the abnormal voltage detection circuit 13 is not functioning correctly following the test.

[0068] During this functional test, the second manual control 161 is configured so that its activation prevents the external indicator 162 from sending the first voltage presence signal to the outside, in the event that the prescribed activation signal SI has been sent by the abnormal voltage detection circuit 13 (VB). This case corresponds to the correct operation of the abnormal voltage detection circuit 13 during the test. The user thus realizes, by the fact that the external indicator 162 no longer sends the first voltage presence signal to the outside, that the abnormal voltage detection circuit 13 is functioning correctly following the test. The test circuit 16 allows for continuous testing of the protection device 1 to ensure its proper operation and prevent latent faults.The test circuit 16 can be made up of one or more analog components.

[0069] The second manual control 161 may be in the form of a push button, lever, handle, or other device, and is accessible by a user on the outer surface 18 of the protective device 1. In Figure 5, the method of protecting the equipment E using the protective device 1 comprises step EO (or E2) and step El, which may be followed by one or more sequences of steps E2 and El, possibly with one or more repetitions of step E3 between these steps.

[0070] According to one embodiment of the invention, the inhibit circuit 15 includes one (or more) additional control output 152' for load Z, which can be connected to load Z. Load Z includes one (or more) input 1520' for receiving a stop command, which is connected to the other control output(s) 152'. The presence of the prescribed activation signal SI on the activation input 151, which moves the trigger 153 to the first position PI, causes a stop command signal S4 for load Z to be sent to the other control output 152'. The presence of the control signal S4 on the other control output 152' causes load Z to stop or disconnects load Z from equipment E.Load Z can be stopped by disconnecting the equipment E from the load Z using internal switches (e.g., contactors) within the load Z. These switches are controlled by the presence of the stop command signal S2 on the receiving input(s) 1520'. This protects the equipment E from overvoltages, particularly when the load Z is an active load capable of feeding energy back to the equipment E. The stop command signal S4 for load Z disconnects the load Z to stop the energy supply to it. The load Z can be a controllable load via its receiving input(s) 1520' and can, in some cases, store energy, such as mechanical energy (e.g., a rotating mechanical part) or electrical energy (e.g., an electric motor). The control output 152' can consist of two conductors.

[0071] According to one embodiment of the invention, the abnormal voltage detection circuit 13 and the inhibition circuit 15 are provided in the same housing 10.

[0072] According to one embodiment of the invention, the test circuit 16 can also be provided in the housing 10.

[0073] According to one embodiment of the invention, the power supply circuit 17 can also be provided in the housing 10.

[0074] According to one embodiment of the invention, the power bypass circuit 14 may also be provided, in whole or in part, within the housing 10. For example, the power switch 142 may be provided within the housing 10, and the first resistor 141 may be provided outside the housing 10 (due to the possibility of a large amount of energy being dissipated by the ohmic effect through the first resistor 141). In another example, the power switch 142 and the first resistor 141 may be provided within the housing 10.

[0075] Of course, the embodiments, characteristics, possibilities and examples described above can be combined with each other or selected independently of each other.

Claims

DEMANDS 1. A device (1) for protecting equipment (E) to be powered by a high-voltage DC bus (B), the protective device (1) comprising a first terminal (11) for connection to a first conductor (B1) of the bus (B) and a second terminal (12) for connection to a second conductor (B2) of the bus (B), the first conductor (B1) and the second conductor (B2) being intended to connect the equipment (E) to a high-voltage DC power supply source (S) intended to apply a high-voltage DC (HVDC) supply voltage to the equipment (E) having a nominal value (HVDCNOM) of DC supply voltage, characterized in that the protective device (1) further comprises: an inhibition circuit (15) for disconnecting the high-voltage DC power supply source (S), the inhibition circuit (15) comprising an activation input (151) and at least one output (152) control of the high-voltage DC power supply (S), a trip unit (153) and a first manual control (154) disposed on an external surface (18) of the protective device (1), the trip unit (153) being configured to assume and maintain, in response to a prescribed activation signal (SI) on the activation input (151), a first position (PI), which causes a stop control signal (S2) to be sent to the high-voltage DC power supply (S) on at least one control output (152), the trip unit (153) being connected to the first manual control (154), which is configured such that actuation of the first manual control (154) switches the trip unit (153) from the first position (PI) to a second position (P2) not causing the sending of the stop control signal (S2) of the high DC supply voltage source (S) on the at least one control output (152), an abnormal voltage (VB) detection circuit (13), which is connected between the first terminal (11) and the second terminal (12), which has an enable output (131) connected to the enable input (151) and which is configured to send the prescribed enable signal (SI) on the enable output (131), when a voltage (VB) greater than a first prescribed threshold (VMAX) of DC voltage, greater than the nominal value (HVDCNOM) of the high DC supply voltage (HVDC), is detected between the first terminal (11) and the second terminal (12).

2. Device according to claim 1, characterized in that the protection device (1) comprises a power bypass circuit (14) connected between the first terminal (11) and the second terminal (12).

3. Device according to claim 2, characterized in that the power bypass circuit (14) comprises at least one first resistor (141) and at least one switch (142) of power, which are in series between the first terminal (11) and the second terminal (12), the power switch (142) having a control input (143) connected to the activation output (131) and being configured to take a connection state of the first resistor (141) between the first terminal (11) and the second terminal (12) in the case where the prescribed activation signal (SI) is present on the control input (143) and to take a disconnection state of the first resistor (141) between the first terminal (11) and the second terminal (12) in the case where the prescribed activation signal (SI) is absent on the control input (143).

4. Device according to claim 3, characterized in that the power switch (142) comprises at least one transistor (144).

5. A device according to any one of the preceding claims, characterized in that the abnormal voltage detection circuit (13) comprises a resistive voltage divider bridge (132) having at least a second resistor (133) and at least a third resistor (134), which are connected in series between the first terminal (11) and the second terminal (12), and a voltage comparator (135), which is connected in parallel with the at least a third resistor (134) and which is configured to compare the voltage (V3) in parallel with the at least a third resistor (134) to a prescribed reference voltage (VREF), equal to a prescribed divisor factor multiplied by the first prescribed threshold (VMAX) of DC voltage, the prescribed divisor factor being equal to the resistive value (R3) of the at least a third resistor (134),divided by the sum of the resistive value (R2) of at least a second resistor (133) and the resistive value (R3) of at least a third resistor (134), the voltage comparator (135) being configured to send the prescribed activation signal (SI) on the activation output (131), in the case where the voltage (V3) in parallel with at least a third resistor (134) is greater than the prescribed reference voltage (VREF).

6. Device according to any one of the preceding claims, characterized in that the trigger (153) comprises a bistable relay (1530) having as stable states only the first position (PI) and the second position (P2).

7. Device according to any one of the preceding claims, characterized in that the protection device (1) comprises a power supply circuit (17), configured to supply power from the first terminal (11) and the second terminal (12) to the abnormal voltage (VB) detection circuit (13) and / or the inhibition circuit (15).

8. Device according to any one of the preceding claims, characterized in that the protection device (1) comprises a circuit (16) for testing the sending of the activation signal (SI) prescribed by the abnormal voltage (VB) detection circuit (13), the test circuit (16) comprising a second manual control (161) disposed on the outer surface (18) of the protection device (1) and at least one external indicator (162) disposed on the outer surface (18) of the protection device (1), the external indicator (162) being configured to send a first voltage presence signal to the outside, when a voltage (VB) less than or equal to the first prescribed threshold (VMA) of DC voltage is present between the first terminal (11) and the second terminal (12), the second manual control (161) being configured such that the actuation of the second manual control (161) causes a test of the sending of the prescribed activation signal (SI) by the abnormal voltage (VB) detection circuit (13), the sending by the external indicator (162) of the first voltage presence signal to the outside in the case where the prescribed activation signal (SI) has not been sent by the abnormal voltage (VB) detection circuit (13) and the absence of sending by the external indicator (162) of the first voltage presence signal to the outside in the case where the prescribed activation signal (SI) has been sent by the abnormal voltage (VB) detection circuit (13).

9. Device according to any one of the preceding claims, characterized in that the inhibition circuit (15) comprises at least one other output (152') for controlling a load (Z) intended to be connected to the equipment (E), the first position (PI) of the trigger (153) causing the sending of a stop command signal (S4) for the load (Z) on the other control output (152').

10. A method for protecting equipment (E) to be supplied by a high-voltage DC bus (B) using the protection device (1) according to any one of the preceding claims, the first terminal (11) of which is connected to the first conductor (B1) of the bus (B) and the second terminal (12) of which is connected to the second conductor (B2) of the bus (B), the first conductor (B1) and the second conductor (B2) connecting the equipment (E) to a high-voltage DC supply source (S) intended to apply between them a high-voltage DC (HVDC) supply to the equipment (E) having a nominal value (HVDCNOM) of DC supply voltage, characterized in that the method further comprises the following steps: actuation (E0,E2) of the first manual command (154) to move the trigger (153) from the first position (PI) to the second position (P2) without sending the stop command signal (S2) from the high-voltage DC supply source (S) to at least one control output (152), measurement (E1) of the voltage (VB) between the first terminal (11) and the second terminal (12) by the abnormal voltage (VB) detection circuit (13), which sends the prescribed activation signal (SI) to the activation output (131) connected to the activation input (151), in the event that the voltage (VB) between the first terminal (11) and the second terminal (12) is greater than the first prescribed threshold (VMAX) of DC voltage, greater than the nominal value (HVDCNOM) of the high-voltage DC supply, in response to the fact that the prescribed activation signal (SI) is present (E2) on the activation input (151),passage (El) of the trigger (153) from the second position (P2) to the first position (PI), which causes the sending (E2) of the stop signal (S2) of the high source (S), DC supply voltage on at least one control output (152) connected to the high DC supply voltage source (S).

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