Load Commutated SCR Based Multilevel Current Source Inverter Fed Induction Motor Drive

Abstract

A new scheme for realization of a load commutated multilevel current source inverter (CSI) for induction motor with open-end stator windings is presented in this paper. In this scheme there are two SCR based current source inverters at one end of the stator windings and a capacitor-fed voltage source inverter (VSI) at the other end. The current source inverters are operated in a phase shifted manner for generation of multilevel current waveform in the motor. The VSI is controlled to supply adequate reactive power for keeping the power factor at CSI output terminals sufficiently leading to ensure load commutation of SCRs. The control scheme of the VSI also ensures balancing of the voltage across the capacitor. The proposed topology is experimentally verified on a 1.5hP open-end winding induction motor with the help of a digital signal processor TMS320F28335.