Grid-Connected Open-end Winding Induction Motor Drives

An open winding approach can lead to substantial performance improvement on grid-connected induction motors, which are still largely used for constant speed applications. Exploiting an open-end winding configuration to manage bidirectional power flows, the proposed configuration is less expensive than a conventional variable frequency induction motor drive, since a bidirectional controlled rectifier is not required, neither grid-side filters. In constant speed applications the proposed approach not only is able to maximize the average motor efficiency, but also to improve the power factor, limiting the start-up current and compensating the effects of voltage sags. Moreover, an energy storage system can be straightforwardly introduced in the system, enabling load peak shaving and load shifting operations. The proposed approach is first theoretical introduced and analyzed, then a performance assessment is accomplished by simulations.