Devices and methods for determining an electrical overcurrent event

Abstract

A device for detecting an electrical overcurrent event includes a current sensor designed to generate a first detection signal representative of the absolute value of an electric current through an electrical conductor. The device further includes a detection unit designed to generate a second detection signal representative of a change in the electric current over time. The device also includes a setting unit designed to adjust a previously set first threshold for the absolute current value based on the second detection signal. Finally, the device includes a detection unit designed to detect an overcurrent event in the electrical conductor based on a comparison between the first detection signal and the set first threshold.

Description

Technical area

[0001] The present disclosure relates to devices for determining electrical overcurrent events. Additionally, the present disclosure relates to methods for determining electrical overcurrent events that may be performed by such devices. background

[0002] Conventional electrical overcurrent detection may be based on measuring an electrical current and comparing the measurement result with a predetermined threshold, which represents the maximum current allowed to flow before the current flow is interrupted. A disadvantage of this approach is that it can take some time to reach the threshold, and during this time, power and energy consumption also increase. In addition, a delay in the detection itself can add even more time. The rising electrical current can damage or even destroy the electrical system until the final shutdown occurs. Manufacturers and designers of devices for determining electrical overcurrent events are constantly striving to improve their products.In particular, it may be desirable to develop devices and methods that provide rapid and reliable detection of electrical overcurrent events so that damage or destruction of the electrical system can be avoided.

[0003] JP 2012-65459 A relates to an overcurrent detection device and an overcurrent detection method. EP 1 770 863 B1 relates to an overcurrent protection device. DE 10 2018 207 491 A1 relates to an electrical circuit and a method for operating an electrical circuit. Summary

[0004] One aspect of the present disclosure relates to a device for detecting an electrical overcurrent event. The device comprises a current sensor configured to generate a first detection signal representative of an absolute current value of an electrical current through an electrical conductor. The device further comprises a detection unit configured to generate a second detection signal representative of a temporal change in the electrical current. The device further comprises a setting unit configured to set a previously set first threshold value for the absolute current value based on the second detection signal.The device further comprises a detection unit configured to detect an overcurrent event in the electrical conductor based on a comparison between the first detection signal and the set first threshold value.

[0005] Another aspect of the present disclosure relates to a method for detecting an electrical overcurrent event. The method includes a process of generating a first detection signal representative of an absolute current value of an electrical current through an electrical conductor. The method further includes a process of generating a second detection signal representative of a temporal change in the electrical current. The method further includes a process of setting a first threshold for the absolute current value. The method further includes a process of adjusting the first threshold based on the second detection signal. The method further includes a process of detecting an overcurrent event in the electrical conductor based on a comparison between the first detection signal and the adjusted first threshold. Brief description of the drawings

[0006] Devices and methods according to the disclosure are described in more detail below based on the drawings. Similar reference numerals may denote corresponding similar parts. The technical features of the various illustrated examples may be combined, provided they are not mutually exclusive, and / or they may be selectively omitted if they are not described as necessarily required. Fig. 1 illustrates a block diagram of an apparatus 100 for determining an electrical overcurrent event according to the disclosure. Fig. 2 illustrates a circuit diagram of an apparatus 200 for determining an electrical overcurrent event according to the disclosure. Fig. 3 illustrates an electrical system 300s including a device 300 for determining an electrical overcurrent event according to the disclosure. Fig. 4 illustrates a flowchart of a method for determining an electrical overcurrent event according to the disclosure. Fig. Figure 5 illustrates a timing diagram for detecting an electrical overcurrent event. Fig. 6 illustrates a timing diagram for detecting an electrical overcurrent event using an apparatus according to the disclosure. Detailed description

[0007] The device 100 of the Fig. 1 is illustrated in a general manner to qualitatively specify aspects of the present disclosure. The device 100 may be expanded with one or more aspects described in connection with other examples. For example, the later-described Fig. 2 shows a more detailed version of a device 200 according to the disclosure.

[0008] The device 100 may include a current sensor 2, a sensing unit 4, a setting unit 6, and a detection unit 8. The current sensor 2 may be configured to generate a first sensing signal 10 representative of an absolute current value of an electrical current through an electrical conductor (not shown). The sensing unit 4 may be configured to generate a second sensing signal 12 representative of a temporal change in the electrical current through the electrical conductor. The setting unit 6 may be configured to set 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 set first threshold value 14.In particular, at least one of the sensing unit 4, the setting unit 6, or the detection unit 8 can be implemented as a discrete component external to the current sensor 2. It should be noted that an embodiment of the components of the device 100 is not limited to a specific type. Rather, the components of the device 100 can be implemented in different ways. More detailed exemplary embodiments of the components of the device are described in connection with the . Fig. 2 shown and described.

[0009] The device 200 of the Fig. 2 can be considered as a more detailed version of the device 100 of the Fig. 1. The device 200 may be configured to detect an electrical 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 power rail or a 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 plurality of resistors 26A to 26C, which may be configured as shown in Fig. 2 illustrates how they can be connected.

[0010] The current sensor 2 can be configured to generate and output a first detection signal 10 representative of an absolute current value of an electric current flowing through the electrical conductor 16. In particular, the first detection signal 10 can be an analog signal. The current sensor 2 is not limited to a specific type, and the detection of the electric current can be based on any suitable technique. For example, the current sensor 2 can be Hall-based, magnetoresistive (MR)-based, shunt-resistor-based, a current transformer (for alternating current only), etc. The current sensor 2 can output the first detection signal 10 to a first (upper) input of the second comparator 22B.

[0011] A second inductor 18B may be connected to a path of electrical current through the electrical conductor 16. The second inductor 18B may or may not be considered part of the device 200. The first inductor 18A may be coupled to the second inductor 18B, i.e., the inductors 18A and 18B may be coupled inductors. In medium voltage (MV) and high voltage (HV) electrical systems (such as an 800 V DC system), galvanic isolation may be provided between the first inductor 18A and the electrical conductor 16 to meet certain clearance and creepage distance requirements.

[0012] A temporal change (or gradient) of the electric current through the electrical conductor 16 can lead to a voltage induced across the first inductor 18A. In particular, the induced voltage U can be based on the formula U(t)=L⋅dl(t)dt where U is the induced / measured voltage across the inductance L of the first inductor 18A, and dl(t)dt is the temporal change (or gradient) of the electric current I through the electrical conductor 16.

[0013] The detection of the temporal variation of the electric current I can be carried out using the principle of self-induction. It should be noted that the inductance value L of the first inductor 18A can be well-defined and precisely known. This means that the induced voltage U and thus the temporal variation of the electric current through the electrical conductor 16 can be determined precisely and reliably. In a non-limiting example, a temporal variation of approximately 800Aμs and an inductance L of approximately 10 nH can result in a voltage across the first inductor 18A of approximately 8 V. Accordingly, since a small inductance L of approximately 10 nH can apparently provide a sufficiently strong induced voltage of approximately 8 V, the first inductor 18A does not necessarily add too much unwanted inductance to the device 200 or an electrical system including the device 200. A detection signal representative of the temporal variation of the electrical current can be provided to a first (upper) input of the first comparator 22A.

[0014] The first inductor 18A can be implemented in different ways. The following examples for implementing the first inductor 18A may have in common that no additional inductance needs to be introduced, but rather an existing inductance of a respective implementation can be used. In particular, the value of an existing inductance can be well-defined and precisely known.

[0015] In one example, the first inductor 18A may be a coil structure that may be integrated into the current sensor 2. In this context, it is possible, for example, to integrate a dedicated sensing coil structure into a current sensing ASIC. In another example, the first inductor 18A may be a wire-on-chip structure designed for calibration of the current sensor 2. That is, the wire-on-chip normally used for calibration may be used as a sensing element. In another example, the first inductor 18A may be implemented as a PCB coil structure, wherein the power rail 16 may be used as the primary inductance. In another example, the first inductor 18A may be integrated into a power device, such as a wide-bandgap switch.In another example, the first inductor 18A may be implemented in the form of a dedicated coupled inductor as a secondary winding of a current edge limiting inductor (if used) or another inductor that may be present in the application under consideration.

[0016] The first IDAC 20A may be configured to provide a signal representative of a second threshold value for the voltage induced across the first inductor 18A. In particular, the signal provided by the first IDAC 20A may be an analog signal. In this context, it should be noted that providing the second threshold value (or a corresponding threshold voltage) is not limited to the use of the first IDAC 20A. Rather, providing the second threshold value may also be based on other suitable components or techniques, such as a voltage / resistance divider, (filtered) pulse width modulation (PWM), VDAC (Voltage Digital to Analog Converter), etc. The second threshold value may be set variably and may be static during operation of the device 200.Since the induced voltage across the first inductor 18A can be associated with a temporal change in the current through the electrical conductor 16, the second threshold can be referred to as a current rise threshold. An output of the first IDAC 20A can be provided to a second (lower) input of the first comparator 22A.

[0017] The first comparator 22A may be supplied with a supply voltage (see signal ground 28 and pin 30 for the supply voltage). The first comparator 22A may be configured to receive the previously described signals from the first inductor 18A and the first IDAC 20A, and may perform a comparison between the voltage induced across the first inductor 18A and the set second threshold. Based on such a comparison, the first comparator 18A may be configured to output a second detection signal 12. In particular, the second detection signal 12 may correspond to a voltage proportional to the temporal change (or slope) of the electrical current through the electrical conductor 16. Returning to the example of the Fig. 1, the recording unit 4 of the Fig. 1 at least one of the first inductor 18A, the first IDAC 20A or the first comparator 22A of the Fig. 2 included.

[0018] The second IDAC 20B may be configured to provide a signal representative of the first threshold value for the absolute current value of the electric current through the electrical conductor 16. In particular, the signal provided by the second IDAC 20B may be an analog signal. In this context, it should be noted that providing the first threshold value (or a corresponding threshold voltage) is not limited to the use of the second IDAC 20B. Rather, providing the first threshold value may also be based on other suitable components or techniques, such as a voltage / resistance divider, (filtered) pulse width modulation (PWM), VDAC (Voltage Digital to Analog Converter), etc. The first threshold value may be set variably and may be static during operation of the device 200. The first threshold value may be referred to as an absolute current threshold value.The output signal of the second IDAC 20B may be adjusted (in particular, lowered) based on an output of the transistor 24, as described below.

[0019] The transistor 24 is not limited to any particular type. In one example, the transistor 24 may be a field-effect transistor including a gate terminal, a drain terminal, and a source terminal. In another example, the transistor 24 may be a bipolar junction transistor including a base terminal, a collector terminal, and an emitter terminal. A control terminal 32 (e.g., gate or base) of the transistor 24 may be connected to an output of the first comparator 22A. Additionally, the lower terminal of the transistor 24 may be connected to the signal ground 28, while the upper terminal of the transistor 24 may be connected to a node 34 disposed between the output of the second IDAC 20B and a second (lower) input of the second comparator 22B.

[0020] The transistor 24 may be configured to adjust (in particular, lower) the first threshold value for the absolute current value as output by the second IDAC 20B. In this regard, an input of the control terminal 32 of the transistor 24 may be based on the second detection signal 12 provided by the first comparator 22A. That is, an amount by which the first threshold value is lowered may be based on the second detection signal 12 and thus on the temporal change of the electrical current through the electrical conductor 16. Returning to the example of the Fig. 1, the setting unit 6 of the Fig. 1 the transistor 24 of the Fig. 2. In this context, it should be noted that, in another example, the first comparator 22A can be replaced by an amplifier configured to linearly control the input of the transistor 24. In such a case, the transistor 24 can not only be driven on / off as with the output of the first comparator 22A, but it can also be linearly controlled depending on the voltage or current change rate provided by the inductor 18A. The greater the temporal increase of the electrical current through the electrical conductor 16, the more the first threshold can be lowered, especially when a linear amplifier is used.

[0021] The second (lower) input of the second comparator 22B may be configured to receive the set first threshold 14 in the form of an analog signal. In addition, as previously described, the first detection signal 10 may be received at the first (upper) input of the second comparator 22B. The second comparator 22B may be configured to compare the first detection signal 10 and the set first threshold 14 and to provide an output signal based on this comparison. The output signal 36 may represent a detection signal configured to indicate an electrical overcurrent event in the electrical conductor 16. If the measured absolute current value is greater than the set first threshold, an electrical overcurrent event may have occurred and thus be indicated by the detection signal 36. Returning to the example of the Fig. 1, the detection unit 8 of the Fig. 1 contain the second comparator 22B.

[0022] The device 200 according to the disclosure can outperform conventional devices with respect to detecting an overcurrent event in the electrical conductor 16. To detect such an electrical overcurrent event, conventional devices can only perform a simple comparison between the measured absolute current value of the electrical current and a (non-adjusted) first threshold value. However, such an approach can be flawed because a certain amount of time can pass before the overcurrent event is detected and the electrical current through the electrical conductor 16 can be shut off. During this delay, the electrical current can still increase and even become so high that it can damage or destroy the device. An exemplary timing diagram for detecting an electrical overcurrent event based on such a conventional approach is described in connection with Fig. 5 shown and described.

[0023] In contrast to the described conventional approach, the devices according to the disclosure can take into account not only the measured absolute current value of the electric current, but additionally its temporal evolution or temporal change, ie dl(t)dt. The temporal change of the electric current contains information about the specific amount by which the electric current increases over time. One way to account for this information is to add this specific amount of increase to the measured absolute current value, so that an absolute current value adjusted in this way can exceed the first threshold at an earlier time. An alternative approach that provides the same effect is to lower the first threshold by the specific amount, as previously discussed in connection with Fig. 2. The first threshold is reduced so that the electrical overcurrent event can be detected at an earlier time. In particular, the first threshold can be reduced proportionally to the temporal increase of the electrical current. The higher the temporal increase of the electrical current (i.e., the more the electrical current increases), the more the first threshold is reduced. An exemplary timing diagram for detecting an overcurrent event with a device according to the disclosure is described in connection with Fig. 6 shown and described.

[0024] Short-circuit events can lead to a rapid increase in electrical current. In one case, a temporal increase in electrical current can reach an exemplary value of approximately 800Aμs Accordingly, it should be possible to respond to a short-circuit event by interrupting the electrical current through the electrical conductor 16 within a time frame of nanoseconds. To provide such fast response times, the signal processing performed by the devices according to the disclosure may preferably be analog due to the very fast signal dynamics.

[0025] The device 200 can optionally be designed to implement the discussed feature of additionally taking into account the temporal change dl(t)dt to activate and deactivate when detecting electrical overcurrent. The temporal variation during a short-circuit condition can be significantly higher than the temporal variation of a nominal electrical current that contains ripple. Thus, it is possible to set a third threshold for the temporal variation. If the specified value of the temporal variation is higher than the third threshold, the temporal variation can be taken into account when detecting electrical overcurrent events; otherwise, it cannot be taken into account.

[0026] Fig. 3 illustrates an electrical system 300s including a device 300 for determining an electrical overcurrent event according to the disclosure. The electrical system 300s may include or correspond to a circuit including a DC power supply 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 some or all of the features of the devices 100 and 200 of the Fig. 1 and Fig. 2. For simplicity, the device 300 is shown as a simple rectangle, with only the first inductor 18A explicitly illustrated to illustrate inductive coupling between the first inductor 18A of the device 300 and the second inductor 18B of the circuit.

[0027] During regular operation of the electrical system 300s, the circuit breaker 40 may be closed, and an electrical current may flow through the circuit and an electrical conductor 16 thereof. In some cases, a short-circuit event 44 may occur, which may result in an increase in the electrical current through the electrical conductor 16 within a very short period of time. The device 300 may be configured to detect an associated electrical overcurrent event, as described in connection with the Fig. 1 and Fig. 2. In this context, device 300 may output a detection signal 36 indicative of the electrical overcurrent event. Circuit breaker 40 may be configured to receive detection signal 36 and interrupt (or turn off) the electrical current in response to receiving detection signal 36. In the illustrated example, circuit breaker 40 is in an open state, and the electrical current was interrupted due to short-circuit event 44.

[0028] For example, the devices described herein may be used in various industrial and automotive applications. In some non-limiting examples, the described mechanisms may be integrated into current sensors, dedicated ASICs, or power semiconductor components. In the non-limiting example of Fig. 3, the electrical system 300s may correspond to a direct current system (see DC power supply 38). DC power distribution systems may be used in many residential and industrial applications, such as data centers, commercial and residential buildings, telecommunications systems, power grids, etc. Compared to AC systems, DC systems may provide higher efficiency, lower complexity, and greater readiness for integration with various local power sources and DC electronic loads. However, it is understood that the concepts discussed herein are not necessarily limited to DC electrical systems. In further examples, devices according to the disclosure may also be used in AC systems. In the example of Fig. 3 In addition, one or more components of the system (such as an included current sensor) may generate an AC ripple that may be superimposed on the DC current.

[0029] Fig. 4 illustrates a flowchart of a method for detecting an electrical overcurrent event according to the disclosure. The method may be performed by any of the previously described devices and may thus be read in conjunction with the preceding figures. At 46, a first detection signal may be generated, wherein the first detection signal may be representative of an absolute current value of an electrical current through an electrical conductor. Returning to the example of Fig. 2, the electric current can flow through the bus bar 16, and the current sensor 2 can generate the first detection signal 10, which is provided at the first (upper) input of the second comparator 22B.

[0030] At 48, a second detection signal may be generated, wherein the second detection signal may be representative of a temporal change in the electrical current. Returning to the example of Fig. 2, the electrical current flowing through the bus bar 16 may change over time, so that inductive coupling between the inductors 18A and 18B may result in an induced voltage across the first inductor 18A. The induced voltage may be measured, and the measurement signal may be provided to the first (upper) input of the first comparator 22A. Additionally, a second threshold for the induced voltage may be set, and the first IDAC 20A (or an equivalent component as described above) may output a signal representing the second threshold to the second (lower) input of the first comparator 22A. A comparison between the induced voltage and the second threshold may be performed by the first comparator 22A.Based on this comparison, the first comparator 22A (or an equivalent component as described above) can output the second detection signal 12, which is representative of a temporal change in the electric current. In particular, the second detection signal 12 can correspond to a voltage proportional to the temporal change in the electric current through the busbar 16.

[0031] At 50, a first threshold value for the absolute current value can be set. Returning to the example of Fig. 2, the second IDAC 20B (or an equivalent component as described above) may generate and output a signal representing the first threshold.

[0032] At 52, the first threshold can be set based on the second detection signal. Returning to the example of Fig. 2, the second detection signal 12 (e.g., a voltage proportional to the time change of the electric current) can be used as input to the control terminal 32 of the transistor 24. The voltage applied to the control terminal 32 can control a current between the other terminals (e.g., source and drain) of the transistor 24. In particular, a current flowing between the other terminals of the transistor 24 can decrease 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 decreased. In other words, the more the electric current through the power rail 16 increases, the more the first threshold can be decreased.

[0033] At 54, an electrical overcurrent event in the electrical conductor may be detected based on a comparison between the first detection signal and the set first threshold. Returning to the example of Fig. 2, the set first threshold 14 may be provided to the second (lower) input of the second comparator 22B. The second comparator 22B may perform a comparison between the set first threshold 14 and the first detection signal 10 received at the first (upper) input of the second comparator 22B. Based on this comparison, the second comparator 22B may output the detection signal 36 indicating whether or not an electrical overcurrent event has occurred.

[0034] The procedure of Fig. 4 may include further actions. For example, the method may further include interrupting the electrical current in response to detecting the overcurrent event. Returning to the example of Fig. 3, the detection signal 36 indicating an electrical overcurrent event in the busbar 16 may be provided to the circuit breaker 40. In response to receiving the detection signal 36 indicating an electrical overcurrent event, the circuit breaker 40 may interrupt and shut off the electrical current through the busbar 16.

[0035] In another example, the method may further include detecting a short circuit event based on the second detection signal and interrupting the electrical current in response to detecting the short circuit event. Returning to the example of Fig. 2, the second detection signal 12 may correspond to a voltage that is proportional to a temporal change in the electrical current through the busbar 16. When a short-circuit event occurs, a temporal change in the electrical current and thus the value of the induced voltage may increase within a short period of time. Accordingly, the second detection signal 12 may be designed to indicate the occurrence of the short-circuit event. Returning to the example of Fig. 3, the circuit breaker 40 may also be configured to interrupt the electrical current through the electrical conductor 16 in response to the second detection signal 12 indicating the short-circuit event. For example, the circuit breaker 40 may interrupt the electrical current if the second detection signal 12 exceeds a corresponding predetermined threshold.

[0036] Fig. Figure 5 illustrates a timing diagram for detecting an electrical overcurrent event in an electrical system. Detecting an electrical overcurrent event according to the timing diagram of Fig. 5 can be performed using conventional equipment. The illustrated diagram plots an absolute current value I of an electric current through an electrical conductor (e.g., a bus) of the electrical system against time t. The specific values ​​given below are exemplary and in no way limiting.

[0037] During regular operation of the electrical system, the electric current can reach a nominal current value I nom until a short-circuit event occurs. In one example, the current level I nomhave a value of approximately 20 A. The short-circuit event may increase the value of the electrical current. In the non-limiting example illustrated, the temporal change dl(t)dt of the electric current may be linear. In further examples, the slope of the electric current may have a non-linear shape. The slope of the electric current may depend on the system inductance. In one example, a DC bus voltage V may have a value of approximately 800 V and a total inductance L in the short-circuit state may have a value of approximately 1 µH. Accordingly, the slope of the electric current may dl(t)dt=VL a value of approximately 800VμH or about 800Aμs have.

[0038] After a certain time, the electric current can reach a predetermined threshold I thfor the absolute current value. In one example, the threshold value I th be chosen so that it is greater than approximately twice the rated current value I nom In a special case, the threshold value can have an exemplary value of about 50 A. With the current increase in the short circuit condition described above of about 800Aμs the threshold value I th can be achieved within a time of about 62 ns.

[0039] A further time interval may elapse before the overcurrent event (or fault) is detected, and yet another time interval may elapse before the electrical current is finally switched off, for example by means of a circuit breaker, as exemplified in connection with Fig. 3. Assuming a delay in the detection mechanism of approximately 1 µs (e.g., with a Hall-based current sensor or similar, without taking other delays into account), the electrical current can rise to more than approximately 800 A (i.e., a factor of more than about 15 of the nominal threshold value) within this delay until final shutdown. Such immense current values ​​can easily lead to damage or even destruction of the device and other components of the electrical system. It should be noted that the sensor's detection mechanism is not the only factor that can contribute to a delay; the delay until final shutdown can be even greater.

[0040] Fig. Figure 6 illustrates a timing diagram for detecting an electrical overcurrent event in an electrical system using a device according to the disclosure. The considered short-circuit scenario may be similar to the one previously discussed in connection with Fig. 5 discussed similar. In Fig. 6, a first bold line illustrates the absolute current value I of an electric current through an electrical conductor (e.g., a bus), plotted against time t. In addition, a second bold line illustrates a voltage U induced across a first inductor, plotted against time t. For comparison, a thin dotted line illustrates the previously discussed graph of Fig. 5.

[0041] Similar to Fig. 5, the electric current during regular operation of the electrical system may reach a nominal current value I nomuntil a short-circuit event occurs. The short-circuit event can cause the value of the electric current I to increase over time and a voltage V ind induced across the first inductor. Note that the induced voltage V ind is available immediately when the electric current begins to rise, i.e., no delay needs to be considered in this regard. Accordingly, if the value of the induced voltage V ind is greater than a threshold value V th for the induced voltage, the short circuit event (or fault) can be detected almost immediately.

[0042] After the short-circuit event has been detected, a further period of time may elapse until the electrical current is interrupted and switched off, for example by a circuit breaker, as exemplified in the context of the example of Fig. 3. Until the electrical current is switched off, the induced voltage V ind remain essentially constant. When the electric current is switched off and thus decreases over time, the voltage induced at the first inductance can become negative.

[0043] In the previously discussed example of Fig. 5 was the threshold value for the absolute current value I th In contrast, in the example of Fig. 6, the threshold for the absolute current value may have been adjusted (lowered) based on the temporal change of the current, as described in connection with previous examples. A comparison between the timing diagrams of the Fig. 5 and Fig. 6 shows that interrupting the electrical current can be performed more quickly when the electrical overcurrent event is detected with a device according to the disclosure. Examples

[0044] In the following, devices and methods for detecting an electrical overcurrent event are explained using examples.

[0045] Example 1 is an apparatus for detecting an electrical overcurrent event, the apparatus comprising: a current sensor configured to generate a first detection signal representing an absolute current value of an electrical current through an electrical conductor; a detection unit configured to generate a second detection signal representing a temporal change in the electrical current; a setting unit configured to set a previously set first threshold for the absolute current value based on the second detection signal; and a detection unit configured to detect an overcurrent event in the electrical conductor based on a comparison between the first detection signal and the set first threshold.

[0046] Example 2 is a device according to Example 1, wherein the sensing unit comprises: a first inductor, wherein a voltage induced across the first inductor is based on the temporal change of the electric current.

[0047] Example 3 is a device according to Example 2, wherein the detection unit comprises: a comparator configured to compare the induced voltage with a set second threshold for the induced voltage and output the second detection signal based on the comparison.

[0048] Example 4 is a device according to Example 2 or 3, wherein an inductance value of the first inductor is known and precisely defined.

[0049] Example 5 is a device according to any one of Examples 2 to 4, further comprising: a second inductor connected in a path of the electrical current, wherein the first inductor is coupled to the second inductor.

[0050] Example 6 is a device according to any one of the preceding examples, wherein the adjustment unit comprises: a transistor configured to lower the first threshold for the absolute current value, wherein an input of a control terminal of the transistor is based on the second detection signal.

[0051] Example 7 is a device according to any one of the preceding examples, wherein the detection unit comprises: a comparator configured to compare the first measurement signal with the set first threshold and output a detection signal indicative of an electrical overcurrent event.

[0052] Example 8 is an apparatus according to Example 7, further comprising: a circuit breaker configured to receive the detection signal and interrupt the electrical current in response to receiving the detection signal.

[0053] Example 9 is a device according to Example 8, wherein the circuit breaker is a solid-state circuit breaker.

[0054] Example 10 is an apparatus according to example 8 or 9, wherein: the second detection signal is configured to indicate a short circuit event, and the circuit breaker is configured to interrupt the electrical current in response to the second detection signal indicating the short circuit event.

[0055] Example 11 is a device according to any one of Examples 2 to 10, wherein the first inductor is a coil structure integrated into the current sensor.

[0056] Example 12 is a device according to any one of Examples 2 to 10, wherein the first inductor is a wire-on-chip structure configured for calibration of the current sensor.

[0057] Example 13 is a device according to any one of the preceding examples, wherein at least one of the sensing units, the setting unit, or the detection unit is implemented as a discrete component external to the current sensor.

[0058] Example 14 is a device according to any one of the preceding examples, wherein the electrical conductor is part of a direct current system.

[0059] Example 15 is a method for detecting an electrical overcurrent event, the method comprising: generating a first detection signal representing an absolute current value of an electrical current through an electrical conductor; generating a second detection signal representing a temporal change in the electrical current; setting a first threshold for the absolute current value; adjusting the first threshold based on the second detection signal; and detecting an electrical overcurrent event in the electrical conductor based on a comparison between the first detection signal and the adjusted first threshold.

[0060] Example 16 is a method according to Example 15, further comprising: interrupting the electrical current in response to detecting the electrical overcurrent event.

[0061] Example 17 is a method according to example 15 or 16, wherein generating the second detection signal comprises: measuring a voltage across an inductor, the voltage being induced based on the temporal change in the electrical current.

[0062] Example 18 is a method according to Example 17, wherein generating the second detection signal comprises: setting a second threshold for the induced voltage and generating a voltage proportional to the temporal change of the electric current based on a comparison between the induced voltage and the second threshold.

[0063] Example 19 is a method according to Example 18, wherein adjusting the first threshold comprises: lowering the first threshold based on the voltage proportional to the change in the electric current over time.

[0064] 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 detection signal; and interrupting the electrical current in response to detecting the short circuit event.

[0065] Although the present disclosure has been described with reference to illustrative examples, this description is not intended to be limited. Various modifications and combinations of the illustrative examples, as well as other examples of the disclosure, will be apparent to those skilled in the art from this description. Therefore, the appended claims are intended to encompass all such modifications or examples.

Claims

[1] An apparatus for detecting an electrical overcurrent event, the apparatus comprising: a current sensor (2) configured to generate a first detection signal (10) representative of an absolute current value of an electrical current through an electrical conductor (16); a detection unit (4) designed to generate a second detection signal (12) representative of a temporal change in the electric current; a setting unit (6) configured to set a previously set first threshold value for the absolute current value based on the second detection signal (12); and a detection unit (8) configured to detect an overcurrent event in the electrical conductor (16) based on a comparison between the first detection signal (10) and the set first threshold value (14). [2] Device according to claim 1, wherein the detection unit (4) comprises: a first inductor (18A), wherein a voltage induced across the first inductor (18A) is based on the temporal change of the electric current. [3] Device according to claim 2, wherein the detection unit (4) comprises: a comparator (22A) configured to compare the induced voltage with a set second threshold value for the induced voltage and output the second detection signal based on the comparison. [4] The device according to claim 2 or 3, wherein an inductance value of the first inductor (18A) is known and precisely defined. [5] Device according to one of claims 2 to 4, further comprising: a second inductor (18B) connected in a path of electrical current, wherein the first inductor (18A) is coupled to the second inductor (18B). [6] Device according to one of the preceding claims, wherein the setting unit (6) comprises: a transistor (24) configured to lower the first threshold for the absolute current value, wherein an input of a control terminal (32) of the transistor (24) is based on the second detection signal. [7] Device according to one of the preceding claims, wherein the detection unit (8) comprises: a comparator (22B) configured to compare the first detection signal (10) with the set first threshold value (14) and output a detection signal (36) indicative of an electrical overcurrent event. [8] The device of claim 7, further comprising: a circuit breaker (40) configured to receive the detection signal (36) and interrupt the electrical current in response to receipt of the detection signal (36). [9] The device of claim 8, wherein the circuit breaker (40) is a solid-state circuit breaker. [10] Device according to claim 8 or 9, wherein: the second detection signal is designed to indicate a short-circuit event, and the circuit breaker (40) is configured to interrupt the electrical current in response to the second detection signal indicating the short-circuit event. [11] Device according to one of claims 2 to 10, wherein the first inductor (18A) is a coil structure integrated into the current sensor (2). [12] Device according to one of claims 2 to 10, wherein the first inductor (18A) is a wire-on-chip structure designed for calibration of the current sensor (2). [13] Device according to one of the preceding claims, wherein at least one of the sensing unit (4), the setting unit (6) or the detection unit (8) is implemented as a discrete component external to the current sensor (2). [14] Device according to one of the preceding claims, wherein the electrical conductor (16) is part of a direct current system. [15] A method for detecting an electrical overcurrent event, the method comprising: Generating a first detection signal (10) representative of an absolute current value of an electrical current through an electrical conductor (16); Generating a second detection signal representative of a temporal change in the electric current; Setting a first threshold for the absolute current value; Setting the first threshold based on the second detection signal; and Detecting an electrical overcurrent event in the electrical conductor (16) based on a comparison between the first detection signal (10) and the set first threshold value (14). [16] The method of claim 15, further comprising: Interrupting the electrical current in response to detecting the electrical overcurrent event. [17] The method of claim 15 or 16, wherein generating the second detection signal comprises: Measuring a voltage across an inductor (18A), wherein the voltage is induced based on the temporal change of the electric current. [18] The method of claim 17, wherein generating the second detection signal comprises: Setting a second threshold for the induced voltage, and Generating a voltage proportional to the temporal change of the electric current based on a comparison between the induced voltage and the second threshold value. [19] The method of claim 18, wherein setting the first threshold comprises: Lowering the first threshold based on the voltage proportional to the change in the electric current over time. [20] A method according to any one of claims 15 to 19, further comprising: Detecting a short-circuit event based on the second detection signal; and Interrupting the electrical current in response to detecting the short circuit event.

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