Single-phase to three-phase ac-dc-ac converter based on cascaded transformers rectifier and open-end winding induction motor

A single-phase to three-phase ac-dc-ac converter is proposed and analyzed in this paper for application in electric rail systems and in rural distribution grid. This system is composed of two cascaded transformers multilevel converter and two conventional two-level three-phase inverter feeding an openend winding induction motor. Model and a control strategy of the system are developed. Compared to the conventional single-phase to three-phase converter, the proposed topology has lower voltage and power ratings in power switches. In addition, the control system ensures balanced dc-link voltages and sinusoidal grid current with high power factor. Simulated and experimental results are also presented to demonstrate the feasibility of the proposed circuit.