Multilevel power converters have received much attention in recent years due to their high power and high voltage capability. However, a drawback of that structure is its large number of power devices and complexity of the control circuit. This paper proposes an inexpensive three-level three-phase rectifier, which improves the mains power factor and is free from inrush current; and from diode reverse recuperation and turn-on losses as well. The proposed rectifier employs only one three-level leg that operates at both constant switching frequency and constant duty cycle. Also, the proposed rectifier allows sharing the three-level leg, which makes it suitable for topology integration. The performance of the proposed rectifier is verified by theoretical analysis, and simulation and experimental results.

This paper presents the application of the OneCycle Control technique to a single-phase three-leg three-level unified power quality conditioner. The system does not use any matching transformer and has a reduced number of components, since it has only three legs. Besides having a power factor close to unity, the proposed system has fast response, stability, robustness, reduced voltage stress applied to the switches, and a low cost scheme. Simulated and experimental results verify the feasibility of the proposed converter.