5-Level Packed U-Cell (PUC5) Active Front-End Rectifier

Abstract

This article presents the 5-level Packed U-Cell (PUC5) converter as an active front-end (AFE) rectifier designed to achieve high power quality and power factor correction (PFC) in grid-connected applications. Operating in boost mode, the proposed topology significantly mitigates input current harmonics and enables precise regulation of the DC output voltage, making it well-suited for bidirectional DC systems such as electric vehicle (EV) charging infrastructure with Vehicle-to-Grid (V2G) capability. A detailed analysis of the converter’s switching states is conducted, with a focus on identifying redundant states that can be strategically utilized to balance the voltage of the auxiliary capacitor. This balancing is essential to sustain the five-level voltage waveform at the rectifier input, which in turn minimizes voltage distortion and directly reduces current harmonic content. The output voltage is tightly regulated to supply downstream DC loads with high stability. Experimental validation confirms the effectiveness of the proposed PUC5 rectifier, demonstrating its ability to operate with a near-unity power factor while drawing low-distortion current from the AC grid and maintaining robust dynamic performance under varying load conditions.