Control of parallel operation of frequency converters or inverters

摘要

A method and a system for controlling parallel-connected frequency converters or inverter units feeding an alternating-current motor (MOTOR1) provided with parallel windings or separate parallel motors having their shafts mechanically coupled together via a load, in which method the current supplied to the motor is measured.;The frequency converters/inverter units are connected to each other via a data bus, e.g. a fast serial bus, and one of the frequency converters/inverter units (FCON1 or INU1) functions as a master device in such manner that it sends to the other device/devices (FCON2 or INU2) information over the data bus regarding the instantaneous value of the current (I_W1) fed by it to the motor, said other devices functioning as follower devices so that they adjust their own current (I_W2) on the basis of the current of the master device.