Method for operating an electrical power rectifier, as well as an electrical power rectifier

摘要

A method for operating an electrical power rectifier. The power rectifier comprises at least two branches that are connected in parallel to each other, each of the branches comprising at least two power semiconductor elements that are connected in series. The collector-emitter voltage Vce(t) and/or the collector current Ic(t) of one of the power semiconductor elements is detected by means of the method. Furthermore, it is determined whether at least one of the following conditions is met: dVce(t)/dt<(dVce/dt)crit, and/or dIc(t)/dt<(dIc/dt)crit, and or Ic(t_ent)

主权项

1. A method for operating an electrical power rectifier, wherein the power rectifier comprises at least two branches that are connected in parallel to each other, each of the branches comprising at least two power semiconductor elements connected in series, the method comprising:
detecting the collector-emitter voltage and/or the collector current of at least one of the power semiconductor elements; determining whether at least one of the following conditions is met: a first condition wherein a speed of increase of the collector-emitter voltage is lower, at a time of desaturation of the at least one of the power semiconductor elements, than a first prespecified value, and/or a second condition wherein a speed of increase of the collector current at the time of desaturation is lower than a second prespecified value, and/or a third condition wherein the collector current, at a time after expiration of a time delay after the desaturation has started, is smaller than a third prespecified value; and increasing the gate-emitter voltage of at least one of the power semiconductor elements if at least one of the conditions is met.