Load-Commutated SCR-Based Current Source Inverter Fed Induction Motor Drive With Open-End Stator Windings

A new topology of a load-commutated silicon-controlled rectifier (SCR)-based current source inverter (CSI)-fed induction motor drive with open-end stator winding is presented in this paper. The proposed topology has a CSI at one side of the stator winding and a capacitor-fed voltage source inverter (VSI) at the other end. The CSI feeds only active power to the motor and the VSI is controlled to provide the reactive power required for operation of the CSI at leading power factor, thereby facilitating natural commutation of SCRs. This topology does not require any interfacing inductor or separate dc voltage source for the VSI. The control scheme enables operation of the motor even at very low speeds without problems such as commutation failure. The experimental verification of the proposed scheme is carried out on an induction motor with open-end stator windings. A digital signal processor (TMS320F28335) is used for implementation of the control algorithm.