Multilevel Single-Phase AC-DC-AC Converter Based on Packed U Cell

This paper proposes a multilevel single-phase AC-DC-AC converter based on Packed U Cell (PUC) and shared leg. The proposed topology is composed of eight IGBT switches and two dc links. As a result, it is possible to produce five-level voltages in both the rectifier and inverter sides. Compared to the existing five-level solutions the proposed one has a reduced switch count with the same harmonic distortion performance. The proposed system provides a high power factor in the grid side with low harmonic content. Additionally, the load is supplied by a sinusoidal waveform with high power quality with the same frequency as the grid. The topology operates with low dc-link voltages in applications with the same input and output frequency, such as uninterrupted power supplies (UPS) and unified power quality conditioners (UPQC). A detailed analysis of the proposed topology is provided, including the system model, operation principles, space-vector PWM strategy, and control system. Simulations and experimental results have been performed and are discussed in this paper.