Grid-Connected Variable Speed Driven Squirrel-Cage Induction Motor Through a Nine-Switch AC/AC Converter with Leading Power Factor

The nine-switch AC/AC converter (NSC) is an adequate replacement of the back-to-back converter (B2B) for low-voltage and low-power applications. Among its usages, it has been used for power factor (PF) correction in view of its use for AC motor driving. However, the examples in the literature are restricted to motors in the absence of speed control. Therefore, this paper analyzes the operation of a squirrel-cage induction motor (SCIM) connected to the grid through an NSC so that the grid-side control allows changes in power factor while motor-side control is able to set the SCIM speed. Simulation results demonstrate that the NSC can reach the desired characteristics of unit and leading power factor in the presence of speed control.