Circuit breaker device and method

A circuit breaker device for protecting an electrical low-voltage circuit, the circuit breaker device comprising:

• a housing having first connections and second connections for conductors of the low-voltage circuit;
• a series circuit of a mechanical isolating contact unit and an electronic interruption unit electrically connected between said first and second connections;
• said mechanical isolating contact unit being configured to be selectively switched by opening contacts to avoid a current flow or by closing the contacts to allow a current flow in the low-voltage circuit;
• said electronic interruption unit being configured to be selectively switched by semiconductor-based switching elements to a high-resistance state of said switching elements to avoid a current flow or to a low-resistance state of said switching elements to allow a current flow in the low-voltage circuit;
• a current sensor unit for ascertaining a level of an instantaneous current of the low-voltage circuit to output instantaneous current values;
• a control unit connected to said current sensor unit, to said mechanical isolating contact unit, and to said electronic interruption unit, and configured to initiate an avoidance of a current flow in the low-voltage circuit when at least one current threshold value is being exceeded;
• and
• wherein the circuit breaker device is configured to adapt and vary the at least one current threshold value on a basis of the level of the current in the low-voltage circuit;
• a voltage sensor unit connected to said control unit and configured to ascertain a level of the voltage of the low-voltage circuit, to provide instantaneous voltage values;
• wherein instantaneous current threshold values that are dependent on the instantaneous voltage values are present;
• wherein the instantaneous current values are compared with the instantaneous current threshold values, and wherein, when the absolute value of the instantaneous current threshold value is exceeded, the interruption of the low-voltage circuit is initiated.

A method of protecting an electrical low-voltage circuit in a circuit breaker device, the method comprising:

• providing the circuit breaker device with a mechanical isolating contact unit that is connected in series with an electronic interruption unit;
• wherein the mechanical isolating contact unit is configured to be switched by opening contacts so as to avoid a current flow or closing the contacts to allow a current flow in the low-voltage circuit;
• wherein the electronic interruption unit is configured to be switched by semiconductor-based switching elements to a high-resistance state of the switching elements to avoid a current flow or to a low resistance state of the switching elements to allow the current flow in the low-voltage circuit;
• ascertaining a level of the current of the low-voltage circuit to provide instantaneous current values;
• when the instantaneous current value exceeds at least one current threshold value, initiating an avoidance of the current flow of the low-voltage circuit;
• and
• adapting the at least one current threshold value on a basis of a level of the current in the low-voltage circuit such that, in a case of an increasing current, the at least one current threshold value is reduced and that, in a case of a decreasing current, the at least one current threshold value is increased up to a maximum value thereof.

A method of protecting an electrical low-voltage circuit in a circuit breaker device, the method comprising:

• providing the circuit breaker device with a mechanical isolating contact unit that is connected in series with an electronic interruption unit;
• wherein the mechanical isolating contact unit is configured to be switched by opening contacts so as to avoid a current flow or closing the contacts to allow a current flow in the low-voltage circuit;
• wherein the electronic interruption unit is configured to be switched by semiconductor-based switching elements to a high-resistance state of the switching elements to avoid a current flow or to a low resistance state of the switching elements to allow the current flow in the low-voltage circuit;
• ascertaining a level of the current of the low-voltage circuit to provide instantaneous current values;
• when the instantaneous current value exceeds at least one current threshold value, initiating an avoidance of the current flow of the low-voltage circuit;
• and
• adapting the at least one current threshold value on a basis of a level of the current in the low-voltage circuit;
• and
• when a nominal current of the circuit breaker device is exceeded, reducing the at least one current threshold value by a percentage that is dependent on a level of the exceedance of the nominal current in order to obtain an adapted current threshold value.