Method and device for overcurrent shutdown

Abstract

A procedure for overcurrent shutdown is proposed, comprising the following steps: - Capturing and providing a current value as an analog output signal; - a conversion of the analog output signal by means of an analog-to-digital converter, which converts the analog output signal by means of sigma-delta modulation and provides it as a bitstream, characterized in that - the bitstream is converted using a first decimation filter and provided as a first data stream; and - Evaluating the first data stream, wherein a threshold value for a current is compared with the current value from the first data stream, and if at least one threshold value is exceeded, the overcurrent shutdown is triggered by means of a shutdown signal, wherein the shutdown signal is transmitted to at least one signal output and is used for opening a power switch. Furthermore, the invention relates to a device.

Description

[0001] The invention relates to a method according to the preamble of claim 1 and a device according to the preamble of claim 9.

[0002] Low-voltage circuit breakers with a mechanical contact system have long been known and are widely used worldwide. More recently, circuit breakers with power semiconductors have become available, replacing mechanical contacts. These enable arc-free and wear-free switching operations within microseconds, thereby significantly reducing short-circuit energy.

[0003] Direct current (DC) networks are particularly challenging because they lack current zero crossings for arc quenching and exhibit greater variations in supply line inductance. This leads to high current surges during a short circuit, as there is no short-circuit current-limiting impedance of a transformer. Solid-state breakers, based on anti-series or anti-parallel power semiconductors, are used to manage short circuits in low-inductance networks. These breakers interrupt short circuits within approximately 100 nanoseconds. Detection is achieved using sensors such as Hall-effect and magnetostrictive sensors, which measure DC currents and have high cutoff frequencies. Analog signal conversion to digital signals is performed by a comparator circuit, which compares the setpoint to the actual value and outputs a digital signal if a setpoint is exceeded.These measuring instruments must be equipped with Over Current Detection (OCD), which reduces the number of usable sensors and does not allow different setpoints for positive and negative currents.

[0004] The present invention is based on the objective of providing a faster overcurrent shutdown.

[0005] The problem is solved by a method with the features of independent claim 1 and by a device with the features of independent claim 9. Advantageous embodiments and further developments of the invention are specified in the dependent claims.

[0006] The procedure for an overcurrent shutdown includes the following steps: - Capturing and providing a current value as an analog output signal; - a conversion of the analog output signal by means of an analog-to-digital converter, which converts the analog output signal by means of sigma-delta modulation and provides it as a bitstream, wherein according to the invention - the bitstream is converted using a first decimation filter and provided as a first data stream; and - Evaluating the first data stream, wherein a threshold value for a current is compared with the current value from the first data stream, and if at least one threshold value is exceeded, the overcurrent shutdown is triggered by means of a shutdown signal, wherein the shutdown signal is transmitted to at least one signal output and is used for opening a power switch.

[0007] Overcurrent protection is a protective measure in electrical circuits that interrupts the flow of current when it exceeds a defined current level for a specific period of time. This can be caused by an overload or a short circuit. Overcurrent protection thus protects wiring and equipment from damage due to excessive heat.

[0008] An analog-to-digital converter (ADC) converts analog input signals into digital output signals. The sampling rate and resolution of the ADC can be configured according to the specific application. Examples of ADCs include the Successive Approximation Register (SAR) ADC and the Sigma-Delta ADC.

[0009] Sigma-delta modulation (SDM) is a technique underlying the sigma-delta ADC and is also called delta-sigma modulation. It is an analog-to-digital and digital-to-analog conversion method based on oversampling and noise shaping. An analog input signal is continuously sampled. The sampled signal is converted by a quantizer into a digital signal with a low bit width or bit depth, which introduces a quantization error. This error is accumulated in an integrator to smooth and minimize it over time. An integrated error signal is then fed back and subtracted from the input signal, continuously correcting the quantization error. This process is repeated at a very high sampling rate, often many times higher than the Nyquist rate, thereby shifting the quantization noise to a higher frequency.Finally, a resulting digital signal is passed through a digital low-pass filter that removes high-frequency noise and reduces the signal to the desired sampling rate.

[0010] A decimation filter is a digital filter used to reduce the sampling rate of a signal, and can specifically function as a low-pass filter. This is achieved by first filtering the signal to remove high-frequency components that could cause aliasing, and then processing only every nth value of the signal. The decimation filter can convert the bitstream into a data stream, calculating an analog measurement value in digital representation from a bit sequence.

[0011] The bitstream can be a sequence of the values ​​1 and 0. Depending on the encoding used, a data stream can be calculated from the bitstream.

[0012] The data stream can consist of a sequence of human-readable data points, in particular one or more current intensity values. The order of the data points within the data stream can represent a temporal sequence.

[0013] The circuit breaker can be an electromechanical switch or a switch based on a power semiconductor.

[0014] The present invention describes a method for an advantageous, reliable overcurrent shutdown. This is because, by oversampling the sigma-delta modulation and providing the bitstream, a transmission channel is created that is less sensitive to electromagnetic interference; in particular, bit errors or bit flips, which can cause a false triggering of the overcurrent shutdown, are better avoided.

[0015] The overcurrent shutdown device includes: - a sensor designed to detect and provide a current value as an analog output signal; and - an analog-to-digital converter designed for converting the analog output signal, which converts the analog output signal using sigma-delta modulation and provides it as a bitstream.

[0016] According to the invention, the device comprises: - a first decimation filter, which is designed to convert the bitstream and provide it as a first data stream; and - a peripheral component designed to evaluate the data stream, wherein the peripheral component compares a threshold value for a current with the current value from the first data stream and, if at least one threshold value is exceeded, triggers the overcurrent shutdown by means of a shutdown signal, wherein the peripheral component is designed to transmit the shutdown signal to at least one signal output and thereby open a power switch.

[0017] The present invention describes a device for advantageously faster overcurrent shutdown. This is possible because a separate shutdown path is formed through the interaction of the first decimation filter, the peripheral component, and the signal output. This shutdown path can be operated in parallel with a processor that processes signals and, due to a processing time that is shorter than the processor's cycle time, can always trigger the overcurrent shutdown faster than the processor.

[0018] The shutdown path is a term from machine safety and describes an independent signal path responsible for the safe shutdown of a machine or machine component. The shutdown path is characterized by its decoupling from the rest of the system or other systems, meaning that it does not share cycle time or processor time with other applications and thus eliminates delays.

[0019] In an advantageous embodiment of the invention, the bitstream is provided with a width of 1 bit.

[0020] This makes it advantageously possible to provide a highly robust signal that can be processed with simple and cost-effective hardware, since only one bit per unit of time needs to be captured.

[0021] According to an advantageous embodiment, a second decimation filter will convert the bit stream with a higher value resolution than the first decimation filter and provide it as a second data stream.

[0022] This advantageously allows for the provision of a second data stream with higher value resolution. This second data stream with higher value resolution can then be advantageously used as a data logging source.

[0023] In an advantageous further development of the invention, the threshold value is set during operation or before operation.

[0024] This makes it advantageously possible to set the threshold either in a switched-off state, especially before commissioning, and thus ensure overcurrent protection even before operation, or to set the overcurrent protection during operation, especially depending on the situation.

[0025] According to an advantageous embodiment, the first data stream is provided to a processor.

[0026] This allows a potential overcurrent shutdown to be detected and processed early by the processor. The processing can include triggering functions, particularly acoustic or visual warning functions.

[0027] In an advantageous embodiment of the invention, the shutdown signal for a processor can be provided.

[0028] This makes it advantageously possible for the processor to process the result of the evaluation of the peripheral component; in particular, the processor can store the result as part of a black box.

[0029] The term "black box" refers to an error memory or electronic event log that can be read for later analysis or reconstruction of errors.

[0030] According to an advantageous embodiment, at least one signal output will provide the shutdown signal to a signal input, wherein the signal input is connected to a processor and a warning signal is transmitted to the processor in the event of an overcurrent shutdown.

[0031] This advantageously allows for the detection of an actual triggering of the overcurrent shutdown by the processor. Detecting this actual triggering is advantageously more informative when verifying the correct functioning of the overcurrent shutdown.

[0032] In an advantageous embodiment of the invention, the overcurrent shutdown can only be triggered if a certain number of threshold exceedances are exceeded.

[0033] This advantageously allows for adjusting the sensitivity of the overcurrent protection. The tripping sensitivity can be reduced, in particular by increasing the number of threshold value exceedances required for the overcurrent protection to occur.

[0034] In an advantageous embodiment of the invention, the first decimation filter can be configured to provide the first data stream for a processor and / or the peripheral component can be configured to provide a shutdown signal for the processor and / or a signal output can be connected to a signal input, wherein the signal input is configured to transmit a warning signal to the processor in the event of an overcurrent shutdown.

[0035] This allows overcurrent shutdowns to be advantageously detected at up to three points along the shutdown path, which can be particularly beneficial for a comprehensive analysis of the overcurrent shutdown by the processor and its documentation on the black box. Furthermore, the collection of this comprehensive analysis data on overcurrent shutdowns across a larger number of devices can be advantageously used for training statistical models.

[0036] According to an advantageous embodiment, the processor is configured to determine the threshold value for the peripheral component during or before the operation of a microcontroller.

[0037] This makes it advantageously possible to set the threshold value during the production of the device, while still allowing for subsequent setting by a user.

[0038] In an advantageous embodiment of the invention, a second decimation filter can be configured to convert the bit stream with a higher value resolution than the first decimation filter and provide it to the processor as a second data stream.

[0039] This allows the second data stream to be advantageously used for monitoring by the processor, enabling predictive detection of overcurrent situations and early overcurrent shutdown. This is particularly beneficial when characteristic current profiles may indicate an impending overload or when a sustained current near the threshold could lead to long-term thermal damage to components.

[0040] Further advantages, features, and details of the invention will become apparent from the exemplary embodiments described below and from the drawings. These show, schematically: Fig. 1 an embodiment of a device for overcurrent shutdown in a component view; Fig. 2 an embodiment of the device with feedback of a shutdown signal; Fig. 3 an embodiment of the device with a coupling of a warning signal; Fig. 4 an embodiment of the device as a combination of the embodiments from Fig. 1, Fig. 2 and Fig. 3; and Fig. 5 an embodiment of a device for selective overcurrent shutdown of several current-carrying lines in a component view.

[0041] The Fig. Figure 1 schematically shows a device comprising a sensor 1 for detecting current, an analog-to-digital converter 2, a first decimation filter 3, a peripheral component 6, a signal output 14 and a power switch 7.

[0042] In one operation of the device, sensor 1 detects a current value and provides it as an analog output signal 9. In a next step, analog-to-digital converter 2 converts the analog output signal 9 using sigma-delta modulation and provides a bitstream 10.

[0043] The bitstream 10 is converted by means of a first decimation filter 3 and provided as a first data stream 11. Finally, a peripheral component 6 evaluates the bitstream 10, comparing a current threshold value with the current value from the first data stream 11, and if at least one threshold value is exceeded, overcurrent shutdown is triggered by means of a shutdown signal 21, the shutdown signal 21 being transmitted to at least one signal output 14 and used to open a power switch 7.

[0044] A first parameterization interface 18 enables parameterization of the first decimation filter 3 and a third parameterization interface 20 enables parameterization of the second decimation filter 4, whereby two different reductions of a sampling rate of the analog output signal 9 can be made through both parameterization interfaces.

[0045] In other words, by performing a sigma-delta conversion of the analog-to-digital converter 2, the analog output signal 9 was oversampled relative to a Nyquist theorem, and therefore a practically lossless reduction of the sampling rate is possible through the two decimation filters.

[0046] However, when parameterizing a sampling rate reduction, it must be ensured that a processing signal processor 5, 6 can process the provided data streams 11, 12 quickly enough.

[0047] A second parameterization interface 19 can be used for parameterizing the peripheral module 6. This parameterization can include setting the current threshold. Another parameter can be the number of threshold violations required to trigger the overcurrent shutdown.

[0048] The Fig. Figure 2 schematically shows an embodiment of the device. Fig. 1, which was extended by a feedback of the shutdown signal 21.

[0049] The feedback of the shutdown signal 21 enables the processor 5 to process the result of an evaluation of the peripheral module 6; in particular, the processor 5 can save the result as part of an event log.

[0050] The Fig. Figure 3 schematically shows an embodiment of the device. Fig. 1, which was extended by the coupling of a warning signal 13.

[0051] The coupling of the warning signal 13 enables the detection of an actual triggering of the overcurrent shutdown by the processor 5. The detection of this actual triggering has greater significance in verifying the correct functioning of the overcurrent shutdown.

[0052] The Fig. Figure 4 schematically shows an embodiment of the device. Fig. 1, which also includes features of the devices from Fig. 2 and Fig. 3 combined, so that the processor 5 can process the first data stream 11, the shutdown signal 21 and the warning signal 13, thus enabling a seamless functional check of the device.

[0053] The Fig. Figure 5 schematically shows an embodiment of the device. Fig. 3, wherein the device is in Fig. 5 was expanded for multi-channel operation.

[0054] The analog-to-digital converter 2, the decimation filters 3, 4, and the peripheral module 6 can each be configured in variants with multiple channels a, b, c, thus enabling parallel connection of one sensor each for channels a, b, c. Variants with a higher number of channels are also suitable.

[0055] The in Fig. The embodiment shown in Figure 5 is scalable by increasing the number of channels per analog-to-digital converter 2, decimation filter 3,4 and peripheral component 6.

[0056] Another possibility for scaling is the integration of additional analog-to-digital converters 2, decimation filters 3,4 and peripheral components 6, where the available signal inputs 17 and signal outputs 14 of a microcontroller 8 and a number of interfaces of a processor 5 are limiting factors.

[0057] Similar, equivalent or equivalent elements may be provided with the same reference symbols in one or more of the figures.

[0058] Although the invention has been illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples, nor can other variations be derived from them by a person skilled in the art without leaving the scope of protection of the invention. Reference symbol list 1 sensor 1a Sensor for channel a 1b Sensor for channel b 1c Sensor for channel c 2 analog-to-digital converters 3 First Decimation Filter 4 Second Decimation Filter 5 processor 6 Peripheral component 7 circuit breakers 7a Circuit breaker Channel a 7b Circuit breaker channel b 7c circuit breaker channel c 8 microcontrollers 9 Analog output signal 9a analog output signal channel a 9b analog output signal channel b 9c analog output signal channel c 10 bitstream 10a Bitstream Channel a 10b Bitstream Channel b 10c Bitstream Channel c 11 First data stream 11a First data stream Channel a 11b First data stream Channel b 11c First data stream Channel c 12 Second data stream 12a Second data stream Channel a 12b Second data stream Channel b 12c Second data stream Channel c 13 Warning signal 13a Warning signal Channel a 13b Warning signal Channel b 13c Warning signal Channel c 14 Signal output 14a Signal output Channel a 14b Signal output Channel b 14c Signal output Channel c 17 Signal input 17a Signal input Channel a 17b Signal input Channel b 17c Signal input channel c 18 First parameterization interface 19 Second parameterization interface 20 Third parameter interface 21 Shutdown signal 21a Shutdown signal Channel a 21b Shutdown signal channel b 21c Shutdown signal Channel c

Claims

[1] Overcurrent shutdown procedure comprising the steps: - (S1) Acquiring and providing a current value as an analog output signal (9); - (S2) a conversion of the analog output signal (9) by means of an analog-to-digital converter (2) which converts the analog output signal (9) by means of a sigma-delta modulation and provides it as a bitstream (10), characterized in that - (S3) the bitstream (10) is converted by means of a first decimation filter (3) and provided as a first data stream (11); and - (S4) Evaluating the first data stream (11), wherein a threshold value for a current is compared with the current value from the first data stream (11), and if at least one threshold value is exceeded, the overcurrent shutdown is triggered by means of a shutdown signal (21), wherein the shutdown signal (21) is transmitted to at least one signal output (14) and is used for opening a power switch (7). [2] Method according to claim 1, characterized in that the bit stream (10) is provided with a width of 1 bit. [3] Method according to one of the preceding claims, characterized in that (S5) a second decimation filter (4) converts the bit stream (10) with a higher value resolution than the first decimation filter (3) and provides it as a second data stream (12). [4] Method according to one of the preceding claims, characterized in that (S0) the threshold is set during operation or before operation. [5] Method according to one of the preceding claims, characterized in that (S6) the first data stream (11) is provided for a processor (5). [6] Method according to one of the preceding claims, characterized in that (S7) the shutdown signal (21) is provided for a processor (5). [7] Method according to one of the preceding claims, characterized in that (S8) at least one signal output (14) provides the shutdown signal (21) to a signal input (17), wherein the signal input (17) is connected to a processor (5) and a warning signal (13) is transmitted to the processor (5) in the event of overcurrent shutdown. [8] Method according to one of the preceding claims, characterized in that the overcurrent shutdown is only triggered when a certain number of threshold exceedances are exceeded. [9] Overcurrent shutdown device comprising: - a sensor (1) designed to detect and provide a current value as an analog output signal (9); - an analog-to-digital converter (2) configured for converting the analog output signal (9), which converts the analog output signal (9) by means of sigma-delta modulation and provides it as a bitstream (10), characterized in that - a first decimation filter (3) designed to convert the bit stream (10) and provide it as a first data stream (11); and - a peripheral component (6) configured to evaluate the data stream (11), wherein the peripheral component (6) compares a threshold value for a current with the current value from the first data stream (11) and, if at least one threshold value is exceeded, triggers the overcurrent shutdown by means of a shutdown signal (21), wherein the peripheral component (6) is configured to transmit the shutdown signal (21) to at least one signal output (14) and thereby open a power switch (7). [10] Device according to claim 9, characterized by, that the first decimation filter (3) is configured to provide the first data stream (11) for a processor (5) and / or the peripheral component (6) is configured to provide a shutdown signal (21) for the processor (5) and / or a signal output (14) is connected to a signal input (17), wherein the signal input (17) is configured to transmit a warning signal (13) to the processor (5) in the event of an overcurrent shutdown. [11] Device according to claim 9 or 10, characterized in that the processor (5) is configured to set the threshold for the peripheral component (6) during or before operation of a microcontroller (8). [12] Device according to one of claims 9 to 11, characterized in that a second decimation filter (4) is configured to convert the bit stream (10) with a higher value resolution than the first decimation filter (3) and to provide it to the processor (5) as a second data stream (12).

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