Implementation of multi-level bridgeless PFC rectifiers for mid-power single phase applications

Multi-level approaches to AC/DC power conversion have been successfully deployed in high-voltage high-power industrial applications, and are recently considered for mid-power ranges due to their capability of reducing component sizes and improving efficiency. The main challenge for mid-power deployment is the complexity of sensing circuits and control algorithms used to maintain the capacitor voltage balance, which typically results in expensive and impractical designs. Although several studies have been carried out to address the issue, they have not simplified the system complexity and fully exploited the advantages of multi-level converters. This paper presents a new four-level topology for PFC rectifiers, and demonstrates its performance and practicality through a 200W prototype. The theoretical works and experimental results are also provided to confirm the feasibility of the solution.