Method to avoid AC instabilities in a negative mains supply inverter for a converter with an intermediate DC circuit in case of a dynamic voltage drop, and circuit arrangement for carrying out the method

摘要

A method and apparatus to avoid commutation failure in a regenerative converter of a supply reversible converter of a voltage-source converter, in case of dynamic voltage depression. A firing control of the reversible converter is a function of the value of a link current setpoint of the voltage-source converter. The link current setpoint is determined from a measured link voltage actual value and from a determined link voltage setpoint. A measured link current actual value is monitored for overcurrent. Control signals are supplied to the reversible converter even when there is an overcurrent status message, when the reversible converter is switched over. The reversible converter of the voltage-source converter is thereby protected from commutation failure.