Inverter-controlled induction machine with an extended speed range

摘要

A four pole induction machine with an extended speed range includes a stator with six independent stator coil groups (a pair of said coil groups constitutes a stator phase winding) and two current regulated inverters. Each of the inverters supplies currents to three said stator coil groups belonging to three different phases. The induction machine is operated in two operation modes: as a four pole machine, when both inverters supply currents of identical polarity, and as a two pole machine, when the polarity of currents supplied by one inverter is reversed in respect to the polarity of currents supplied by another inverter. The switching from the four pole operation mode to the two pole operation mode takes place during a constant power operation of the induction machine.