Method for operating a three-phase motor using a converter with a variable frequency and voltage

摘要

A method is proposed for operating a three-phase motor using a converter with a variable frequency and voltage, in the case of which method, according to a first variant, the three-phase motor is operated in a star circuit at a constant power and with a relatively high moment in a lower rotation speed adjustment range, and in a delta circuit at a constant power and with a relatively low moment in an upper rotation speed adjustment range. According to a second variant using a three-phase motor with a reversible pole winding, the three-phase motor is operated using a relatively large number of pole pairs at constant power and with a relatively high moment in a lower rotation speed adjustment range, and with a relatively small number of pole pairs at constant power and with a relatively low moment in an upper rotation speed adjustment range. According to a third variant using two converters and a three-phase motor having two star windings, the three-phase motor is operated with two parallel star windings, each of which is supplied via its own converter, at constant power and with a relatively high moment in a lower rotation speed adjustment range, and with a single star winding, which is supplied via two series-connected converters, at constant power and with a relatively low moment in an upper rotation speed adjustment range.