Circuit-breaker device and method
A circuit breaker device for protecting a low-voltage electric circuit includes a mechanical break contact unit connected in series with an electronic interruption unit. The break contact unit is switchable by opening contacts to prevent current flow or by closing the contacts to allow current flow in the low-voltage circuit. The electronic interruption unit is switchable by semiconductor-based switching elements into a high-resistance state of the switching elements to prevent current flow or into a low-resistance state of the switching elements to allow current flow in the low-voltage circuit. The amplitude of the current in the low-voltage circuit is ascertained to provide instantaneous current values which are compared with at least one current threshold value, and if the threshold value is exceeded, prevention of current flowing in the low-voltage circuit is initiated. The at least one current threshold value is adjusted according to a temperature level of the circuit breaker device.
1 . A circuit-breaker device for protecting a low-voltage electric circuit, the circuit-breaker device comprising:
a housing having first and second terminals for conductors of the low-voltage circuit;
a series-connected arrangement of a mechanical break contact unit and an electronic interruption unit, for an electrical connection of said first and second terminals;
said mechanical break contact unit having contacts and being switchable by opening said contacts for interrupting a current flux or by closing said contacts for conduction of a current flux in the low-voltage circuit;
said electronic interruption unit having semiconductor-based switching elements and being switchable to a high-resistance state of said switching elements for prevention of a current flux or to a low-resistance state of said switching elements for allowance of a current flux in the low-voltage circuit;
a current sensor unit for determining a current level in the low-voltage circuit and making instantaneous current values available, at least one current limiting value being continuously adapted;
a control unit connected to said current sensor unit, to said mechanical break contact unit and to said electronic interruption unit, for initiating prevention of a current flux in the low-voltage circuit in an event of overshooting at least one current threshold value; and
the circuit-breaker device being configured to adjust the at least one current threshold value according to a temperature level of the circuit-breaker device.
2 . The circuit-breaker device according to claim 1 , wherein said first terminals are grid-side terminals, said second terminals are load-side terminals, said mechanical break contact unit is associated with said load-side terminals, and said electronic interruption unit is associated with the grid-side terminals.
3 . The circuit-breaker device according to claim 1 , wherein the at least one current threshold value is adapted to the temperature level by causing the at least one current threshold value to be reduced as the temperature rises, and by causing the at least one current threshold value to be increased as the temperature falls.
4 . The circuit-breaker device according to claim 3 , wherein the at least one current threshold value is increased up to a maximum value of the at least one current threshold value.
5 . The circuit-breaker device according to claim 1 , wherein the temperature level of the circuit-breaker device is a temperature level within said housing of the circuit-breaker device.
6 . The circuit-breaker device according to claim 1 , wherein the temperature level of the circuit-breaker device is a temperature level of the electronic interruption unit.
7 . The circuit-breaker device according to claim 1 , wherein the temperature level of the circuit-breaker device is a temperature level of one of said semiconductor-based switching elements of said electronic interruption unit.
8 . The circuit-breaker device according to claim 1 , which further comprises at least one temperature sensor unit connected to said control unit to determine the temperature level.
9 . The circuit-breaker device according to claim 1 , wherein the temperature level is determined or calculated from a measured current level.
10 . The circuit-breaker device according to claim 8 , wherein the temperature level is determined from the measured current level by executing a calculation involving an electrical model and a thermal model in consideration of an instantaneous current value level.
11 . The circuit-breaker device according to claim 1 , wherein the at least one current limiting value is continuously adapted within a time of less than 20 ms.
12 . The circuit-breaker device according to claim 1 , wherein the at least one current limiting value is continuously adapted within a time of less than 10 ms.
13 . The circuit-breaker device according to claim 1 , wherein the at least one current limiting value is continuously adapted within a time of less than 1 ms.
14 . The circuit-breaker device according to claim 1 , which further comprises an analog comparator comparing the instantaneous current value of the current level with the at least one current threshold value, and initiating the interruption of the current flux in the low-voltage circuit in an event of an overshoot by the current value of the value of the at least one current threshold value.
15 . The circuit-breaker device according to claim 1 , which further comprises a digital-analog converter and a comparator, the at least one current threshold value being calculated digitally, said digital-analog converter converting the calculated digital current threshold value into an analog current threshold value, and the analog current threshold value being fed to said comparator.
16 . A circuit-breaker device for protecting a low-voltage electric circuit, the circuit-breaker device comprising:
a housing having first and second terminals for conductors of the low-voltage circuit;
a series-connected arrangement of a mechanical break contact unit and an electronic interruption unit, for an electrical connection of said first and second terminals;
said mechanical break contact unit having contacts and being switchable by opening said contacts for interrupting a current flux or by closing said contacts for conduction of a current flux in the low-voltage circuit;
said electronic interruption unit having semiconductor-based switching elements and being switchable to a high-resistance state of said switching elements for prevention of a current flux or to a low-resistance state of said switching elements for allowance of a current flux in the low-voltage circuit;
a current sensor unit for determining a current level in the low-voltage circuit and making instantaneous current values available;
a control unit connected to said current sensor unit, to said mechanical break contact unit and to said electronic interruption unit, for initiating prevention of a current flux in the low-voltage circuit in an event of overshooting at least one current threshold value; and
the circuit-breaker device being configured to adjust the at least one current threshold value according to a temperature level of the circuit-breaker device;
the temperature level being converted into a digital temperature value, the digital temperature value being multiplied by a factor, and a resulting product being subtracted from the at least one current threshold value, to obtain an adapted current threshold value.
17 . A circuit-breaker device for protecting a low-voltage electric circuit, the circuit-breaker device comprising:
a housing having first and second terminals for conductors of the low-voltage circuit;
a series-connected arrangement of a mechanical break contact unit and an electronic interruption unit, for an electrical connection of said first and second terminals;
said mechanical break contact unit having contacts and being switchable by opening said contacts for interrupting a current flux or by closing said contacts for conduction of a current flux in the low-voltage circuit;
said electronic interruption unit having semiconductor-based switching elements and being switchable to a high-resistance state of said switching elements for prevention of a current flux or to a low-resistance state of said switching elements for allowance of a current flux in the low-voltage circuit;
a current sensor unit for determining a current level in the low-voltage circuit and making instantaneous current values available;
a control unit connected to said current sensor unit, to said mechanical break contact unit and to said electronic interruption unit, for initiating prevention of a current flux in the low-voltage circuit in an event of overshooting at least one current threshold value; and
the circuit-breaker device being configured to adjust the at least one current threshold value according to a temperature level of the circuit-breaker device;
the temperature level being converted into a digital temperature value, the digital temperature value being reduced by an offset value, and a result being subtracted from the at least one current threshold value, to obtain an adapted current threshold value.
18 . A circuit-breaker device for protecting a low-voltage electric circuit, the circuit-breaker device comprising:
a housing having first and second terminals for conductors of the low-voltage circuit;
a series-connected arrangement of a mechanical break contact unit and an electronic interruption unit, for an electrical connection of said first and second terminals;
said mechanical break contact unit having contacts and being switchable by opening said contacts for interrupting a current flux or by closing said contacts for conduction of a current flux in the low-voltage circuit;
said electronic interruption unit having semiconductor-based switching elements and being switchable to a high-resistance state of said switching elements for prevention of a current flux or to a low-resistance state of said switching elements for allowance of a current flux in the low-voltage circuit;
a current sensor unit for determining a current level in the low-voltage circuit and making instantaneous current values available;
a control unit connected to said current sensor unit, to said mechanical break contact unit and to said electronic interruption unit, for initiating prevention of a current flux in the low-voltage circuit in an event of overshooting at least one current threshold value;
the circuit-breaker device being configured to adjust the at least one current threshold value according to a temperature level of the circuit-breaker device;
a voltage sensor unit for determining a voltage level in the low-voltage circuit and making instantaneous voltage values available;
periodic instantaneous current threshold values being obtained and being dependent upon a periodic temporal characteristic of instantaneous voltage values; and
instantaneous current values being compared, in a phase-related manner, to the instantaneous current threshold values, for initiating an interruption of the low-voltage circuit in an event of a quantitative overshoot of the value of the instantaneous current threshold value.
19 . The circuit-breaker device according to claim 18 , wherein:
the low-voltage circuit assumes a sinusoidal temporal voltage characteristic;
the instantaneous current threshold values assume, quantitatively, a near-sinusoidal temporal current threshold value characteristic, having a minimum value greater than zero; and
the temporal characteristics of voltage and current threshold values are synchronized in a phase-related manner, causing a time point of the amplitude of the voltage to coincide with a time point of the amplitude of the current threshold value.
20 . The circuit-breaker device according to claim 19 , wherein the minimum value is greater than 5% of a maximum value.
21 . The circuit-breaker device according to claim 19 , wherein the minimum value is greater than 10% of a maximum value.
22 . The circuit-breaker device according to claim 19 , wherein the minimum value is greater than 15% of a maximum value.
23 . The circuit-breaker device according to claim 19 , wherein the minimum value is greater than 20% of a maximum value.
24 . The circuit-breaker device according to claim 19 , wherein a region of a zero-crossing of the voltage coincides with a region of the minimum current threshold value.
25 . The circuit-breaker device according to claim 1 , wherein said control unit adapts the at least one current threshold value for prevention of any current flux in the low-voltage circuit, according to the temperature level of the circuit-breaker device.
26 . A non-transitory computer program product having commands stored thereon which, upon execution of the program by a microcontroller, use the circuit-breaker device according to claim 1 to initiate an execution of a method for protecting the low-voltage electric circuit.
27 . A non-transitory computer-readable storage medium, on which the computer program product according to claim 26 is saved.
28 . A method for transmitting a computer program, the method comprising transmitting the program stored on the non-transitory computer program product according to claim 27 on a data transmission signal.