A Family of High Power Factor Current Multilevel Rectifiers Employing a Sinusoidal PWM Technique

This work introduces the use of a sinusoidal pulse-width modulation (PWM) technique applied to two-stage single-phase current multilevel AC-to-DC converters. The use of a medium-frequency PWM strategy leads to a high power factor operation, with reduced harmonic content in the input current. Moreover, a safe distribution of the total current among the semiconductor switches is obtained, which is an inherent feature of the current multilevel converters. The DC-to-DC adopted converter stages employ a two-cell structure and draw a five-level sinusoidal PWM current from the AC utility. Along with theoretical and Pspice simulation results, the paper includes experimental details and waveforms from a 0.5 kW laboratory prototype which prove the practical feasibility regarding the present approach. It is expected that the proposed strategy can be applied to highly inductive DC load power systems