PROJECT TITLE :

Single-Phase AC–AC Double-Star Chopper Cells (DSCC) Converter Without Common DC-Link Capacitor

ABSTRACT:

This paper presents a single-section ac–ac converter based on a modular multilevel cascade converter (MMCC) with double-star chopper cells (DSCC). The converter topology consists of three DSCC legs, in which the middle leg is shared, and it does not gift a common dc-link capacitor. It's suitable for nonregenerative or regenerative low-power and medium-power ac–ac conversions. A voltage-balancing management is presented for regulating the floating dc capacitor voltages. Furthermore, a grid current and cargo voltage management is presented to correct the input power factor and to confirm input/output sinusoidal waveforms. A part-shifted carrier (PSC) pulsewidth modulation (PWM) commands submodules (SMs) using half of PSCs, preserving the characteristics of conventional modulation. Details about a downscaled prototype rated at 3.three kW and 220 V are presented. The experimental results enable validating the control methods and also the effectiveness of the proposed system.