Quenching device for a converter bridge with line regeneration

A method for controlling a quenching device for a converter bridge with line regeneration, comprising:

• providing a converter bridge with at least three inputs electrically connected to a three-phase network and at least two outputs electrically connected to a direct-current motor which feeds, when operated as a generator, current back into the three-phase network via the converter bridge;
• providing a network-time control circuit to control the converter bridge based upon ignition pulses;
• controlling the quenching device by a trigger unit which emits trigger pulses based upon a monitoring of electrical and temporary variables;
• determining a motor output direct current as a function of time;
• forming a second derivation of the output direct current according to the time;
• and
• activating the quenching device if the second derivation assumes a value equal to or greater than zero in an area between two consecutive ignition times.

A quenching device for a converter bridge with line regeneration, comprising:

• a converter bridge with at least three electrical inputs and at least two electrical outputs;
• a network-time control circuit to control the converter bridge based upon ignition pulses;
• a trigger unit to control the quenching device, wherein the trigger unit emits trigger pulses based upon a monitoring of electrical and temporary variables and activates the quenching device if the characteristic value determined from the measured values of the phases deviates by a predetermined value from the theoretical characteristic value;
• a measuring device for measuring waveform of at least two phases of a three-phase network as a function of a phase angle over a predetermined area of the phase angle;
• a determining device to determine a characteristic value from the waveform of the two phases as a function of the phase angle;
• and
• a comparing device to compare the determined characteristic value to a corresponding theoretical characteristic value.