A static “quasi electric shaft” for n similar rotor winding induction motors

In this paper, a regenerative “static electric shaft” topology is presented. This drive is valid for any number of identical motors that have similar mechanical loads. Under this condition, the drive is very stable and motors operate at very similar speeds. Under unbalanced mechanical load, speeds are different, but these differences are mitigated by the effect of a bridge controlled inverter that regenerates active power to the AC lines, as in the well known subsynchronous cascade. This means a high efficient drive. Speed can be regulated through the inverter firing angle. Some preliminary results are shown. This drive is very attractive for those variable speed cases which require a great deal of motors with similar loads, like fans in a tank house of a electrowinning copper plants