Method for operating an active converter connected to an electric machine and means for the implementation thereof

A method for operating an active converter connected to an electric machine, the method, comprising:

• connecting a number of phase terminals via an activatable current control valve in a first converter branch to a first DC voltage terminal and via an activatable current control valve in a second converter branch to a second DC voltage terminal, each of the current control valves of one of the two converter branches having an arresting circuit;
• and
• activating, via the arresting circuit, a voltage arresting function from a first point in time, from which a voltage potential applied at the first DC voltage terminal increases up to a predefined first threshold value, and keeping the voltage arresting function active as long as the voltage potential does not drop below the first threshold value, the voltage arresting function including activating the current control valves having the arresting circuit and thereby establishing a conductive connection between the phase terminal connected to this current control valve and the particular DC voltage terminal;
• wherein the converter is configured to only activate a load dump reaction upon activation conditions from a second point in time if the voltage potential is above a second threshold value at the second point in time, the second point in time being after the first point in time and the second threshold value being below the first threshold value and the load dump reaction including activating all current control valves of the other of the two converter branches and thereby establishing a conductive connection between all phase terminals, and
• wherein the activation conditions include the condition that it is determined that at the second point in time, a supply-side voltage potential applied to an exciter winding of the electric machine is between the voltage potential applied at the first DC voltage terminal and a ground potential if the exciter winding is disconnected from the voltage potential of the vehicle electrical system voltage and/or a current flowing through the exciter winding is below a current threshold value and/or after an initial activation of a load dump reaction, after which further load dump reactions were activated, more than a predefined period of time has elapsed and/or more than a predefined number of load dump reactions were activated.

A processing unit for operating an active converter connected to an electric machine, comprising:

• a processing arrangement configured to perform the following:
• connecting a number of phase terminals via an activatable current control valve in a first converter branch to a first DC voltage terminal and via an activatable current control valve in a second converter branch to a second DC voltage terminal, each of the current control valves of one of the two converter branches having an arresting circuit;
• and
• activating, via the arresting circuit, a voltage arresting function from a first point in time, from which a voltage potential applied at the first DC voltage terminal increases up to a predefined first threshold value, and keeping the voltage arresting function active as long as the voltage potential does not drop below the first threshold value, the voltage arresting function including activating the current control valves having the arresting circuit and thereby establishing a conductive connection between the phase terminal connected to this current control valve and the particular DC voltage terminal;
• wherein the converter is configured to only activate a load dump reaction upon activation conditions from a second point in time if the voltage potential is above a second threshold value at the second point in time, the second point in time being after the first point in time and the second threshold value being below the first threshold value and the load dump reaction including activating all current control valves of the other of the two converter branches and thereby establishing a conductive connection between all phase terminals, and
• wherein the activation conditions include the condition that it is determined that at the second point in time, a supply-side voltage potential applied to an exciter winding of the electric machine is between the voltage potential applied at the first DC voltage terminal and a ground potential if the exciter winding is disconnected from the voltage potential of the vehicle electrical system voltage and/or a current flowing through the exciter winding is below a current threshold value and/or after an initial activation of a load dump reaction, after which further load dump reactions were activated, more than a predefined period of time has elapsed and/or more than a predefined number of load dump reactions were activated.

A computer readable medium having a computer program, which is executable by a processor, comprising:

• a program code arrangement having program code for operating an active converter connected to an electric machine, by performing the following:
• connecting a number of phase terminals via an activatable current control valve in a first converter branch to a first DC voltage terminal and via an activatable current control valve in a second converter branch to a second DC voltage terminal, each of the current control valves of one of the two converter branches having an arresting circuit;
• and
• activating, via the arresting circuit, a voltage arresting function from a first point in time, from which a voltage potential applied at the first DC voltage terminal increases up to a predefined first threshold value, and keeping the voltage arresting function active as long as the voltage potential does not drop below the first threshold value, the voltage arresting function including activating the current control valves having the arresting circuit and thereby establishing a conductive connection between the phase terminal connected to this current control valve and the particular DC voltage terminal;
• wherein the converter is configured to only activate a load dump reaction upon activation conditions from a second point in time if the voltage potential is above a second threshold value at the second point in time, the second point in time being after the first point in time and the second threshold value being below the first threshold value and the load dump reaction including activating all current control valves of the other of the two converter branches and thereby establishing a conductive connection between all phase terminals, and
• wherein the activation conditions include the condition that it is determined that at the second point in time, a supply-side voltage potential applied to an exciter winding of the electric machine is between the voltage potential applied at the first DC voltage terminal and a ground potential if the exciter winding is disconnected from the voltage potential of the vehicle electrical system voltage and/or a current flowing through the exciter winding is below a current threshold value and/or after an initial activation of a load dump reaction, after which further load dump reactions were activated, more than a predefined period of time has elapsed and/or more than a predefined number of load dump reactions were activated.