Device and method for determining overcurrent event

Abstract

The invention relates to a device and a method for determining an overcurrent event. An apparatus for detecting an overcurrent event includes a current sensor configured to generate a first sensing signal representative of an absolute current value of a current through an electrical conductor. The apparatus also includes a sensing unit configured to generate a second sensing signal representative of a temporal change in the current. The apparatus further comprises an adjustment unit configured to adjust a previously set first threshold value for the absolute current value based on the second sensing signal. The apparatus also includes a detection unit configured to detect an overcurrent event in the electrical conductor based on a comparison between the first sensing signal and the adjusted first threshold.

Description

Technical Field

[0001] The present disclosure relates to an apparatus for determining an overcurrent event. In addition, the present disclosure relates to a method for determining an overcurrent event that can be performed by such an apparatus. Background Art

[0002] Conventional overcurrent detection may be based on sensing the current and comparing the sensed result with a predetermined threshold value, which represents the maximum current that may flow before interrupting the current flow. The disadvantage of this approach is that it may take a certain amount of time before the threshold is reached, during which time power and energy may also increase. In addition, even more time may pass due to delays in the detection mechanism itself. The rising current may damage or even destroy the electrical system before the final disconnection event can occur. Manufacturers and designers of devices for determining overcurrent events are constantly working to improve their products. In particular, it may be desirable to develop devices and methods that provide fast and reliable detection of overcurrent events so that damage or destruction of electrical systems can be avoided. Summary of the invention

[0003] One aspect of the present disclosure relates to a device for detecting an overcurrent event. The device includes a current sensor configured to generate a first sensing signal representing an absolute current value of a current passing through an electrical conductor. The device also includes a sensing unit configured to generate a second sensing signal representing a time variation of the current. The device also includes an adjustment unit configured to adjust a previously set first threshold for the absolute current value based on the second sensing signal. The device also includes a detection unit configured to detect an overcurrent event in the electrical conductor based on a comparison between the first sensing signal and the adjusted first threshold.

[0004] Another aspect of the present disclosure relates to a method for detecting an overcurrent event. The method includes an act of generating a first sensing signal representing an absolute current value of a current through an electrical conductor. The method also includes an act of generating a second sensing signal representing a time variation of the current. The method also includes an act of setting a first threshold value for the absolute current value. The method also includes an act of adjusting the first threshold value based on the second sensing signal. The method also includes an act of detecting an overcurrent event in the electrical conductor based on a comparison between the first sensing signal and the adjusted first threshold value. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The apparatus and method according to the present disclosure are described in more detail below based on the accompanying drawings. Similar reference numerals may represent corresponding similar parts. The technical features of the various illustrated examples may be combined as long as they are not mutually exclusive, and / or may be selectively omitted if not described as being necessary.

[0006] Figure 1A block diagram of an apparatus 100 for determining an overcurrent event according to the present disclosure is illustrated.

[0007] Figure 2 A circuit diagram of an apparatus 200 for determining an overcurrent event according to the present disclosure is illustrated.

[0008] Figure 3 An electrical system 300s including an apparatus 300 for determining an overcurrent event according to the present disclosure is illustrated.

[0009] Figure 4 A flow chart of a method for determining an overcurrent event according to the present disclosure is illustrated.

[0010] Figure 5 illustrates a timing diagram for detecting an over-current event.

[0011] Figure 6 A timing diagram for detecting an overcurrent event using a device according to the present disclosure is illustrated. DETAILED DESCRIPTION

[0012] Figure 1 The device 100 is illustrated in a general manner in order to qualitatively specify aspects of the present disclosure. The device 100 may be extended by one or more aspects described in conjunction with other examples. For example, the device 100 described later Figure 2 A more detailed version of the device 200 according to the present disclosure is illustrated.

[0013] The device 100 may include a current sensor 2, a sensing unit 4, an adjustment unit 6, and a detection unit 8. The current sensor 1 may be configured to generate a first sensing signal 10, which represents an absolute current value of a current passing through an electrical conductor (not shown). The sensing unit 4 may be configured to generate a second sensing signal 12, which represents a temporal variation of the current passing through the electrical conductor. The adjustment unit 6 may be configured to adjust a previously set first threshold value for the absolute current value based on the second sensing signal 12. The detection unit 8 may be configured to detect an overcurrent event in the electrical conductor based on a comparison between the first sensing signal 10 and the adjusted first threshold value 14. Specifically, at least one of the sensing unit 4, the adjustment unit 6, or the detection unit 8 may be implemented as a discrete component external to the current sensor 2. It should be noted that the implementation of the components of the device 100 is not limited to a specific type. More specifically, the components of the device 100 may be implemented in various ways. In combination Figure 2 More detailed exemplary embodiments of device components are shown and described.

[0014] Figure 2 The device 200 can be considered as Figure 11. The device 200 is a more detailed version of the device 100. The device 200 can be configured to detect an overcurrent event that may occur in an electrical conductor 16, which may or may not be considered part of the device 200. In the illustrated example, the electrical conductor 16 may correspond to a current rail or bus. The device 200 may include a current sensor 2, a first inductor 18A, a first IDAC (current digital-to-analog converter) 20A, a second IDAC 20B, a first comparator 22A, a second comparator 22B, a transistor 24, and a first inductor 18A. Figure 2 A plurality of resistors 26A to 26C are connected as shown.

[0015] The current sensor 2 can be configured to generate and output a first sensing signal 10, which represents the absolute current value of the current flowing through the electrical conductor 16. Specifically, the first sensing signal 10 can be an analog signal. The current sensor 2 is not limited to a specific type, and the sensing current can be based on any suitable technology. For example, the current sensor 2 can be based on Hall, based on magnetoresistance (MR), based on shunt resistors, current transformers (for AC only), etc. The current sensor 2 can output the first sensing signal 10 to the first (upper) input of the second comparator 22B.

[0016] The second inductor 18B may be connected in the path of the current through the electrical conductor 16. The second inductor 18B may be considered as part of the device 200 or not. The first inductor 18A may be coupled to the second inductor 18B, i.e. the inductors 18A and 18B may be coupled inductors. For the case of medium voltage (MV) and high voltage (HV) electrical systems (such as, for example, 800V DC systems), electrical isolation may be provided between the first inductor 18A and the electrical conductor 16 in order to meet specific clearance and creepage requirements.

[0017] The time variation (or slope) of the current through the electrical conductor 16 may result in a voltage induced across the first inductor 18A. Specifically, the induced voltage U may be based on the formula where U is the induced / measured voltage across the inductance L of the first inductor 18A, and is the time variation (or slope) of the current I through the electrical conductor 16 .

[0018] The detection of the temporal variation of the current I can be performed using the principle of self-inductance. In this respect, it should be noted that the inductance value L of the first inductor 18A can be well defined and precisely known. That is, the induced voltage U and thus the temporal variation of the current through the electrical conductor 16 can be determined in a precise and reliable manner. In a non-limiting example, about 800 The time variation of the current and the inductance L of about 10 nH can result in a voltage of about 8 V across the first inductor 18A. Therefore, since the small inductance L of about 10 nH can obviously provide a sufficiently strong induced voltage of about 8 V, the first inductor 18A does not necessarily add too much unwanted inductance to the device 200 or the electrical system including the device 200. The sense signal representing the time variation of the current can be provided to the first (upper) input of the first comparator 22A.

[0019] The first inductor 18A may be implemented in various different ways. The following examples for implementing the first inductor 18A may have in common that no additional inductance may be introduced, but an already available inductance of the corresponding embodiment may be used. Specifically, the value of the already available inductance may be well defined and precisely known.

[0020] In one example, the first inductor 18A can be a coil structure that can be integrated into the current sensor 2. In this connection, it is possible, for example, to integrate a dedicated sensing coil structure into a current sensing ASIC. In another example, the first inductor 18A can be an on-chip wiring structure that is configured for calibration of the current sensor 2. That is, the on-chip wiring typically used for calibration can be used as a sensing element. In another example, the first inductor 18A can be implemented as a PCB coil structure, in which the current rail 16 can be used as a primary inductance. In another example, the first inductor 18A can be integrated into a power device (such as, for example, a wide bandgap switch). In yet another example, the first inductor 18A can be implemented in the form of a dedicated coupled inductor as a secondary winding of a current slope limiting inductor (if used) or any other inductor that may be present in the application under consideration.

[0021] The first IDAC 20A can be configured to provide a signal representing a second threshold value for the voltage induced across the first inductor 18A. Specifically, the signal provided by the first IDAC 20A can be an analog signal. In this regard, it should be noted that providing a second threshold value (or a corresponding threshold voltage) is not limited to using the first IDAC 20A. More specifically, providing a second threshold value can also be based on other suitable components or technologies, such as, for example, a voltage / resistor divider, a (filtered) pulse width modulation (PWM), a VDAC (voltage digital-to-analog converter), etc. The second threshold value can be variably set and can be static during operation of the device 200. Since the voltage induced across the first inductor 18A can be associated with the time variation of the current through the electrical conductor 16, the second threshold value can be referred to as a current slope threshold value. The output of the first IDAC 20A can be provided to the second (lower) input of the first comparator 22A.

[0022] The first comparator 22A can be powered by a power supply voltage (see signal ground 28 and pin 30 of the power supply voltage). The first comparator 22A can be configured to receive the previously described signals from the first inductor 18A and the first IDAC 20A, and can perform a comparison of the voltage induced across the first inductor 18A with a set second threshold. Based on this comparison, the first comparator 18A can be configured to output a second sensing signal 12. Specifically, the second sensing signal 12 can correspond to a voltage proportional to the time change (or slope) of the current through the electrical conductor 16. Return to reference Figure 1 For example, Figure 1 The sensing unit 4 may include Figure 2 At least one component of the first inductor 18A, the first IDAC 20A, or the first comparator 22A.

[0023] The second IDAC 20B can be configured to provide a signal representing a first threshold value for an absolute current value of a current passing through the electrical conductor 16. Specifically, the signal provided by the second IDAC 20B can be an analog signal. In this regard, it should be noted that providing a first threshold value (or a corresponding threshold voltage) is not limited to using a second IDAC 20B. More specifically, providing a first threshold value can also be based on other suitable components or technologies, such as, for example, a voltage / resistor divider, a (filtered) pulse width modulation (PWM), a VDAC (voltage digital-to-analog converter), etc. The first threshold value can be set variably and can be static during operation of the device 200. The first threshold value can be referred to as an absolute current threshold value. The output signal of the second IDAC 20B can be adjusted (in particular, reduced) based on the output of the transistor 24 as described below.

[0024] Transistor 24 is not limited to a specific type. In one example, transistor 24 can be a field effect transistor, which includes a gate terminal, a drain terminal and a source terminal. In another example, transistor 24 can be a bipolar junction transistor, which includes a base terminal, a collector terminal and an emitter terminal. The control terminal 32 (such as a gate or base) of transistor 24 can be connected to the output of the first comparator 22A. In addition, the lower terminal of transistor 24 can be connected to signal ground 28, and the upper terminal of transistor 24 can be coupled to node 34, which is arranged between the output of the second IDAC 20B and the second (lower) input of the second comparator 22B.

[0025] The transistor 24 can be configured to adjust (particularly lower) the first threshold value for the absolute current value output by the second IDAC 20B. In this regard, the input to the control terminal 32 of the transistor 24 can be based on the second sensing signal 12 provided by the first comparator 22. That is, the amount by which the first threshold value is lowered can be based on the second sensing signal 12, and therefore based on the temporal variation of the current through the electrical conductor 16. Return to reference Figure 1 For example, Figure 1 The adjustment unit 6 may include Figure 2 In this connection, it should be noted that in a further example, the first comparator 22A can be replaced by an amplifier configured to linearly drive the input of the transistor 24. In this case, the transistor 24 can not only be driven on / off like the output of the first comparator 22A, but it can also be linearly controlled according to the amount of voltage (respectively the rate of change of current) given by the inductor 18A. The greater the time increase of the current through the electrical conductor 16, the more the first threshold value can be lowered, especially if a linear amplifier is used.

[0026] The second (lower) input of the second comparator 22B can be configured to receive the adjusted first threshold value 14 in the form of an analog signal. In addition, as previously described, the first sensing signal 10 can be received at the first (upper) input of the second comparator 22B. The second comparator 22B can be configured to compare the first sensing signal 10 with the adjusted first threshold value 14 and provide an output signal based on this comparison. The output signal 36 can represent a detection signal, which is configured to indicate an overcurrent event in the electrical conductor 16. If the measured absolute current value is greater than the adjusted first threshold value, an overcurrent event may have occurred and can therefore be indicated by the detection signal 36. Return to reference Figure 1 For example, Figure 1 The detection unit 8 may include a second comparator 22B.

[0027] The device 200 according to the present disclosure may outperform conventional devices in detecting overcurrent events in the electrical conductor 16. To detect such overcurrent events, conventional devices may only perform a simple comparison between the measured absolute current value of the current and the (unadjusted) first threshold value. However, this approach may be flawed because a certain time interval may pass until the overcurrent event is detected and the current through the electrical conductor 16 can be cut off. During this delay, the current may still rise and may even become so high that it may damage or destroy the device. Figure 5 An exemplary timing diagram for detecting an overcurrent event based on this conventional approach is shown and described.

[0028] In contrast to the conventional methods described, the device according to the invention can take into account not only the measured absolute current value of the current but also its temporal evolution or temporal variation, i.e. The temporal variation of the current includes information about a specific amount by which the current increases over time. One possibility for interpreting this information is to add this specific amount of increase to the measured absolute current value, so that the absolute current value thus adjusted may exceed the first threshold at an earlier time. An alternative method that provides the same effect is to reduce the first threshold by a specific amount, as described above in conjunction with Figure 2 The first threshold is lowered so that an overcurrent event can be detected at an earlier time. Specifically, the first threshold can be lowered in proportion to the time increase of the current. The higher the time increase of the current (i.e., the stronger the current increase), the more the first threshold is lowered. Figure 6 An exemplary timing diagram for detecting an overcurrent event using an apparatus according to the present disclosure is shown and described.

[0029] A short circuit event can cause a rapid increase in current. In one case, the temporal increase in current can have a duration of about 800 seconds. Thus, it should be possible to react to a short circuit event by interrupting the current through the electrical conductor 16 within a nanosecond time frame. In order to provide such a fast reaction time, the signal processing performed by the device according to the present disclosure may preferably be analog due to the very fast signal dynamics.

[0030] The device 200 may optionally be configured to activate and deactivate additionally taking into account time variations when an overcurrent is detected. The discussed features. The time variation under short circuit conditions can be much higher than the time variation of the nominal current including the ripple. Therefore, it may be possible to set a third threshold for the time variation. If the determined value of the time variation is higher than the third threshold, the time variation can be considered when detecting an overcurrent event, otherwise the time variation is not considered.

[0031] Figure 3 An electrical system 300s including a device 300 for determining an overcurrent event according to the present disclosure is illustrated. The electrical system 300s may include or may correspond to a circuit including a DC power source 38, a circuit breaker 40, a resistor (or load) 42, a second inductor 18B, and the device 300. The circuit breaker 40 and the second inductor 18B may or may not be considered part of the device 300. For example, the circuit breaker 40 may be a solid-state circuit breaker. The device 300 may include Figure 1 and Figure 2For simplicity, the device 300 is illustrated as a simple rectangle, with only the first inductor 18A explicitly shown to illustrate the inductive coupling between the first inductor 18A of the device 300 and the second inductor 18B of the circuit.

[0032] During normal operation of the electrical system 300s, the circuit breaker 40 may be closed and current may flow through the circuit and its electrical conductors 16. In some instances, a short circuit event 44 may occur, which may cause the current through the electrical conductors 16 to increase in a very short period of time. The device 300 may be configured to detect associated overcurrent events, such as in conjunction with Figure 1 and Figure 2 In this regard, the device 300 may output a detection signal 36 indicating an overcurrent event. The circuit breaker 40 may be configured to receive the detection signal 36 and interrupt (or cut off) the current in response to receiving the detection signal 36. In the illustrated example, the circuit breaker 40 is in an open state, and the current has been interrupted due to the short circuit event 44.

[0033] For example, the devices described herein can be used in various industrial and automotive applications. In certain non-limiting examples, the described mechanisms can be integrated into current sensors, dedicated ASICs, or power semiconductor components. Figure 3 In a non-limiting example, the electrical system 300s may correspond to a DC system (see DC power source 38). DC power distribution systems may be used in many residential and industrial applications, such as, for example, data centers, commercial and residential buildings, telecommunication systems, transportation grids, and the like. Compared to AC systems, DC systems may provide higher power efficiency, less complexity, and greater readiness for integration with various local power sources and electronic DC loads. However, it should be understood that the concepts discussed herein are not necessarily limited to DC electrical systems. In further examples, devices according to the present disclosure may also be used in AC electrical systems. In addition, in Figure 3 In an example of, one or more components of the system (such as, for example, an included current sensor) may generate an AC ripple that may be superimposed on the DC current.

[0034] Figure 4 A flow chart of a method for detecting an overcurrent event according to the present disclosure is illustrated. The method may be performed by any of the previously described devices and may therefore be read in conjunction with the previous figures. At 46, a first sense signal may be generated, wherein the first sense signal may represent an absolute current value of a current passing through an electrical conductor. Return to Reference Figure 2 , current may flow through the current rail 16 and the current sensor 2 may generate a first sense signal 10 , which is provided to a first (upper) input of a second comparator 22B.

[0035] At 48, a second sensed signal may be generated, wherein the second sensed signal may represent a temporal variation of the current. Figure 2 In the example of, the current flowing through the current rail 16 can vary over time, so that the inductive coupling between the inductors 18A and 18B can cause a voltage induced across the first inductor 18A. The induced voltage can be measured, and the measurement signal can be provided to the first (upper) input of the first comparator 22A. In addition, a second threshold for the induced voltage can be set, and the first IDAC 20A (or an equivalent component as described above) can output a signal representing the second threshold to the second (lower) input of the first comparator 22A. The comparison between the induced voltage and the second threshold can be performed by the first comparator 22A. Based on this comparison, the first comparator 22A (or an equivalent component as described above) can output a second sensing signal 12 representing the time variation of the current. Specifically, the second sensing signal 12 can correspond to a voltage proportional to the time variation of the current through the current rail 16.

[0036] At 50, a first threshold value for the absolute current value may be set. Return to Reference Figure 2 For example, the second IDAC 20B (or an equivalent component as described above) can generate and output a signal representing the first threshold.

[0037] At 52, the first threshold may be adjusted based on the second sensing signal. Figure 2 In an example of, the second sensing signal 12 (e.g., a voltage proportional to the time change of the current) can be used as an input to the control terminal 32 of the transistor 24. The voltage applied to the control terminal 32 can control the current between the other terminals (e.g., the source and the drain) of the transistor 24. Specifically, the current flowing between the other terminals of the transistor 24 can reduce the signal output by the second IDAC 20B. The greater the voltage applied to the control terminal 32, the more the signal output by the second IDAC 20B can be reduced. In other words, the greater the increase in the current through the current rail 16, the more the first threshold can be reduced.

[0038] At 54, an overcurrent event in the electrical conductor may be detected based on a comparison between the first sense signal and the adjusted first threshold. Figure 2 For example, the adjusted first threshold value 14 can be provided to the second (lower) input of the second comparator 22B. The second comparator 22B can perform a comparison between the adjusted first threshold value 14 and the first sensing signal 10 received at the first (upper) input of the second comparator 22B. Based on the comparison, the second comparator 22B can output a detection signal 36 indicating whether an overcurrent event has occurred.

[0039] Figure 4The method may include additional actions. For example, the method may include an additional action of interrupting the current in response to detecting an overcurrent event. Return to reference Figure 3 For example, a detection signal 36 indicating an overcurrent event in the current rail 16 may be provided to the circuit breaker 40. In response to receiving the detection signal 36 indicating an overcurrent event, the circuit breaker 40 may interrupt and cut off the current through the current rail 16.

[0040] In further examples, the method may include further actions of detecting a short circuit event based on the second sensing signal and interrupting the current flow in response to detecting the short circuit event. Figure 2 In the example of , the second sensing signal 12 may correspond to a voltage proportional to the time variation of the current through the current rail 16. In the event of a short circuit event, the time variation of the current may increase in a short time, and thus the value of the sensed voltage may increase in a short time. Therefore, the second sensing signal 12 may be configured to indicate the occurrence of a short circuit event. Return to reference Figure 3 For example, the circuit breaker 40 can also be configured to interrupt the current through the electrical conductor 16 in response to the second sensing signal 12 indicating a short circuit event. For example, if the second sensing signal 12 exceeds a corresponding predetermined threshold, the circuit breaker 40 can interrupt the current.

[0041] Figure 5 A timing diagram for detecting an overcurrent event in an electrical system is shown. Conventional devices can be used to perform Figure 5 Detection of an overcurrent event with a timing diagram of FIG. In the diagram shown, the absolute current value I of the current through an electrical conductor (eg a bus) of an electrical system is plotted against time t. The specific values ​​given below are exemplary and by no means limiting.

[0042] During normal operation of the electrical system, the current may have a nominal current value I nom , until a short circuit event may occur. In one example, the nominal current level I nom may have a value of about 20 A. Due to the occurrence of a short circuit event, the value of the current may increase. In the non-limiting illustrated example, the time variation of the current can be linear. In other examples, the slope of the current can have a nonlinear form. The slope of the current can depend on the system inductance. In one example, the DC bus voltage V can have a value of about 800V, and the total inductance L under short-circuit conditions can have a value of about 1μH. Therefore, the slope of the current Can have about 800 or about 800 The value of .

[0043] After a certain amount of time, the current can reach a predetermined overcurrent threshold value Ith In one example, the threshold I th can be selected to be greater than the nominal current value I nom In certain cases, the threshold value may have an exemplary value of about 50A. At about 800 Under short-circuit conditions, the threshold I can be reached in about 62ns using the current slope specified above. th .

[0044] A further time interval may elapse before an overcurrent event (or fault) is detected, and the current is ultimately interrupted (e.g. by incorporating a Figure 3 A further time interval may pass before the circuit breaker (described exemplarily) is switched off. Assuming a delay of the detection mechanism of about 1 μs (e.g. using a Hall-based current sensor, etc., not taking into account additional delays), within this delay, the current may rise to more than about 800 A (i.e. about 15 times the nominal threshold) before it is finally switched off. Such huge current values ​​may easily lead to damage or even destruction of the device and other components of the electrical system. Note that not only the detection mechanism of the sensor may add delay, i.e. the delay until the final switch-off may be even greater.

[0045] Figure 6 FIG. 1 illustrates a timing diagram for detecting an overcurrent event in an electrical system using a device according to the present disclosure. The short circuit scenario considered may be similar to the one previously described in conjunction with FIG. Figure 5 The scenario in question. Figure 6 , a first bold line illustrates the absolute current value I of the current through the electrical conductor (e.g., a bus) plotted against time t. Furthermore, a second bold line illustrates the voltage U induced across the first inductor plotted against time t. For comparison purposes, the thin dashed line illustrates the absolute current value I of the current through the electrical conductor (e.g., a bus) plotted against time t. Furthermore, a second bold line illustrates the voltage U induced across the first inductor plotted against time t. Figure 5 of the previous discussion.

[0046] Similar to Figure 5 , during normal operation of the electrical system, the current may have a nominal current value I nom , until a short circuit event may occur. Due to the short circuit event, the value of the current I can increase over time, and the voltage V ind can be induced across the first inductor. Note that when the current starts to rise, the induced voltage V ind is immediately available, i.e. no delay needs to be considered in this regard. Therefore, if the induced voltage V ind The value is greater than the threshold value V for sensing voltage th , a short circuit event (or fault) can be detected almost immediately.

[0047] After a short circuit event is detected, the current is interrupted and cut off (e.g. by combining Figure 3Before the current is cut off, the induced voltage V ind The voltage induced across the first inductor may become negative when the current is switched off and thus decreases over time.

[0048] exist Figure 5 In the example discussed previously, the threshold for the absolute current value is I th However, in Figure 6 In the example of , the threshold value for the absolute current value may have been adjusted (lowered) based on the time variation of the current as described in conjunction with the previous example. Figure 5 and Figure 6 A comparison between the timing diagrams of shows that if an overcurrent event is detected using a device according to the present disclosure, interrupting the current can be performed faster.

[0049] Example

[0050] Hereinafter, an apparatus and method for detecting an overcurrent event are explained by way of examples.

[0051] Example 1 is a device for detecting an overcurrent event, the device comprising: a current sensor configured to generate a first sensing signal representing an absolute current value of a current passing through an electrical conductor; a sensing unit configured to generate a second sensing signal representing a time variation of the current; an adjustment unit configured to adjust a previously set first threshold value for the absolute current value based on the second sensing signal; and a detection unit configured to detect an overcurrent event in the electrical conductor based on a comparison between the first sensing signal and the adjusted first threshold value.

[0052] Example 2 is the apparatus of Example 1, wherein the sensing unit comprises: a first inductor, wherein a voltage induced across the first inductor is based on a temporal variation of a current.

[0053] Example 3 is a device according to Example 2, wherein the sensing unit includes: a comparator configured to compare the induced voltage with a set second threshold value for the induced voltage, and output a second sensing signal based on the comparison.

[0054] Example 4 is the apparatus of Example 2 or 3, wherein the inductance value of the first inductor is known and well-defined.

[0055] Example 5 is a device according to any of Examples 2 to 4, further comprising: a second inductor connected in a path of the current, wherein the first inductor is coupled to the second inductor.

[0056] Example 6 is a device according to any of the preceding examples, wherein the adjustment unit includes: a transistor configured to reduce the first threshold value for the absolute current value, wherein an input to a control terminal of the transistor is based on the second sensing signal.

[0057] Example 7 is a device according to any of the preceding examples, wherein the detection unit includes: a comparator configured to compare the first sensing signal with the adjusted first threshold and output a detection signal indicating an overcurrent event.

[0058] Example 8 is the apparatus according to Example 7, further comprising: a circuit breaker configured to receive the detection signal and interrupt the current in response to receiving the detection signal.

[0059] Example 9 is the apparatus according to Example 8, wherein the circuit breaker is a solid-state circuit breaker.

[0060] Example 10 is the apparatus of example 8 or 9, wherein: the second sensing signal is configured to indicate a short circuit event, and the circuit breaker is configured to interrupt the current in response to the second sensing signal indicating the short circuit event.

[0061] Example 11 is the apparatus of any of Examples 2 to 10, wherein the first inductor is a coil structure integrated into the current sensor.

[0062] Example 12 is a device according to any of Examples 2 to 10, wherein the first inductor is an on-chip wiring structure configured for calibration of the current sensor.

[0063] Example 13 is a device according to any of the preceding examples, wherein at least one of the sensing unit, the adjusting unit, or the detecting unit is implemented as a discrete component external to the current sensor.

[0064] Example 14 is an apparatus according to any of the preceding examples, wherein the electrical conductor is part of a DC system.

[0065] Example 15 is a method for detecting an overcurrent event, the method comprising: generating a first sensing signal representing an absolute current value of a current passing through an electrical conductor; generating a second sensing signal representing a time variation of the current; setting a first threshold for the absolute current value; adjusting the first threshold based on the second sensing signal; and detecting an overcurrent event in the electrical conductor based on a comparison between the first sensing signal and the adjusted first threshold.

[0066] Example 16 is the method of Example 15, further comprising: interrupting the current in response to detecting the overcurrent event.

[0067] Example 17 is the method of example 15 or 16, wherein generating the second sensing signal comprises measuring a voltage across the inductor, wherein the voltage is sensed based on a time variation of the current.

[0068] Example 18 is a method according to Example 17, wherein generating the second sensing signal includes setting a second threshold for the induced voltage, and generating a voltage proportional to a time variation of the current based on a comparison between the induced voltage and the second threshold.

[0069] Example 19 is a method according to Example 18, wherein adjusting the first threshold comprises: lowering the first threshold based on a voltage proportional to a time change of the current.

[0070] Example 20 is a method according to any one of Examples 15 to 19, further comprising: detecting a short circuit event based on the second sensing signal; and interrupting current in response to detecting the short circuit event.

[0071] Although the present disclosure has been described with reference to illustrative examples, this description is not intended to be interpreted in a limiting sense. Various modifications and combinations of the illustrative examples and other examples of the present disclosure will be apparent to those skilled in the art upon reference to the description. Therefore, it is apparent that the appended claims include any such modifications or examples.

Claims

1. A device for detecting an overcurrent event, the device comprising: A current sensor (2) configured to generate a first sensing signal (10) representing an absolute current value of a current passing through an electrical conductor (16); A sensing unit (4) configured to generate a second sensing signal (12), wherein the second sensing signal (12) represents a time variation of the current; an adjustment unit (6) configured to adjust a previously set first threshold value for the absolute current value based on the second sensing signal (12); as well as A detection unit (8) is configured to detect an overcurrent event in the electrical conductor (16) based on a comparison between the first sensing signal (10) and the adjusted first threshold value (14).

2. The device according to claim 1, wherein the sensing unit (4) comprises: A first inductor (18A) wherein a voltage induced across the first inductor (18A) is based on the temporal variation of the current.

3. The device according to claim 2, wherein the sensing unit (4) comprises: A comparator (22A) is configured to compare the induced voltage with a set second threshold value for the induced voltage and output the second sensing signal based on the comparison.

4. The device according to claim 2 or 3, wherein the inductance value of the first inductor (18A) is known and well-defined.

5. The device according to any one of claims 2 to 4, further comprising: A second inductor (18B) is connected in the path of the current, wherein the first inductor (18A) is coupled to the second inductor (18B).

6. The device according to any of the preceding claims, wherein the adjustment unit (6) comprises: A transistor (24) is configured to lower the first threshold value for the absolute current value, wherein an input to a control terminal (32) of the transistor (24) is based on the second sensing signal.

7. The device according to any one of the preceding claims, wherein the detection unit (8) comprises: A comparator (22B) is configured to compare the first sensing signal (10) with the adjusted first threshold (14) and output a detection signal (36) indicating an overcurrent event.

8. The device according to claim 7, further comprising: A circuit breaker (40) is configured to receive the detection signal (36) and interrupt the current in response to receiving the detection signal (36).

9. The apparatus of claim 8, wherein the circuit breaker (40) is a solid-state circuit breaker.

10. The apparatus according to claim 8 or 9, wherein: The second sense signal is configured to indicate a short circuit event, and The circuit breaker (40) is configured to interrupt the current in response to the second sensing signal indicating the short circuit event.

11. The device according to any one of claims 2 to 10, wherein the first inductor (18A) is a coil structure integrated into the current sensor (2).

12. The device according to any one of claims 2 to 10, wherein the first inductor (18A) is an on-chip wiring structure configured for calibration of the current sensor (2).

13. The device according to any of the preceding claims, wherein at least one of the sensing unit (4), the adjusting unit (6) or the detecting unit (8) is implemented as a discrete component external to the current sensor (2).

14. The device according to any of the preceding claims, wherein the electrical conductor (16) is part of a DC system.

15. A method for detecting an overcurrent event, the method comprising: generating a first sense signal (10) representing an absolute current value of a current passing through an electrical conductor (16); generating a second sensing signal, the second sensing signal representing a time variation of the current; Setting a first threshold value for the absolute current value; adjusting the first threshold based on the second sensing signal; and An overcurrent event in the electrical conductor (16) is detected based on a comparison between the first sensing signal (10) and the adjusted first threshold (14).

16. The method according to claim 15, further comprising: The current is interrupted in response to detecting the overcurrent event.

17. The method according to claim 15 or 16, wherein generating the second sensing signal comprises: A voltage is measured across an inductor (18A), wherein the voltage is sensed based on the temporal variation of the current.

18. The method of claim 17, wherein generating the second sensing signal comprises: generating a second threshold value for the sensed voltage, and A voltage proportional to the temporal variation of the current is generated based on a comparison between the induced voltage and the second threshold value.

19. The method of claim 18, wherein adjusting the first threshold comprises: The first threshold is lowered based on the voltage proportional to the temporal change of the current.

20. The method according to any one of claims 15 to 19, further comprising: detecting a short circuit event based on the second sensing signal; as well as The current flow is interrupted in response to detecting the short circuit event.

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