An Efficient Grid-Connected Three-Phase Single-Stage Boost Current Source Inverter

The proposed three-phase boost Current Source Inverter (CSI) is equipped with Reverse-Blocking IGBTs (RB-IGBT) and the Phasor Pulse Width Modulation (PPWM) switching pattern to provide system efficiency greater than 92% and high boost ratios (VLL/Vdc) up to 3.5 in a single stage. The boost CSI results in elimination of dc-dc boost converter or a step-up transformer needed in dc-ac converters operating with a dc input voltage lower than the output line-to-line voltage. In this paper, the relationship between the fundamental component of the inverter output current and the PPWM modulation index is derived and then confirmed by simulation and experimentally obtained data in both stand-alone and grid-tied modes of operation. In this work, a 2 kW, 208 VLLrms, 60 - 120 VdcRB-IGBT-based boost CSI is prototyped to explore capabilities of the grid-tied boost CSI in terms of efficiency and THD for various input dc voltage and output power levels.