A New Scheme for SCR Based Current Source Inverter Fed Induction Motor Drive with Open-End Stator Windings

A new scheme for SCR based Current Source Inverter (CSI) fed Induction Motor (1M) with open-end stator windings is presented in this paper. The proposed topology has an SCR based CSI at one end of the stator windings and a capacitor fed Voltage Source Inverter (VSI) at the other end. A major drawback of the conventional SCR based CSI for 1M drive is the requirement of forced commutation circuit for SCRs, making the system complex. The topology proposed in this paper obviates the need for any forced commutation circuit as simple load commutation of SCRs is achieved with the help of the voltage source inverter. CSI is controlled to feed only the active power whereas VSI controls the reactive power to make the power factor at CSI terminal leading and, thereby, facilitating the natural commutation of thyristors. The control scheme is validated by extensive simulation on a MATLAB-Simulink platform. The experimental verification of the topology and control algorithm is then carried out on a 1.5 HP Induction motor with the help of a digital signal processor TMS320F28335.