High-Power-Density Single-Phase Three-Level Flying-Capacitor Buck PFC Rectifier

Wenlong Qi, Sinan Li, Huawei Yuan, Siew Chong Tan, S.Y.Ron Hui

Research output: Contribution to journalArticlepeer-review

45 Citations (SciVal)
378 Downloads (Pure)


Active pulsating-power-buffering (PPB) is an effective technique to reduce the energy storage requirement of a single-phase power-factor-correction (PFC) rectifier. Existing single-phase solutions with active PPB, however, generally suffer from high voltage stresses, leading to increased power losses as well as the need for high-voltage-rating semiconductor switches. Previous works have been focusing on two-level switching converter configurations, and thus have failed to address the high-voltage-stress problem. In this paper, a single-phase three-level flying-capacitor PFC rectifier with PPB embedded switching is proposed. The flying capacitor not only clamps the voltage stresses of all power devices but also functions as a PPB capacitor. The operating principles, control methods, and design guidelines are detailed and the feasibility of the proposed converter is verified through a 48-W (48-V/1-A) hardware prototype. The proposed rectifier is shown to achieve nearly 50% reduction of the voltage stresses, 72% reduction of the buffering capacitor's volume and 23.8% reduction of the magnetic core size, as compared to a state-of-the-art two-level solution recently proposed. This new approach of formulating single-phase PFC rectifiers with active PPB could dramatically boost the system's efficiency and power density whilst reducing cost.
Original languageEnglish
Article number8630661
Pages (from-to)10833-10844
Number of pages12
JournalIEEE Transactions on Power Electronics
Issue number11
Early online date31 Jan 2019
Publication statusPublished - 1 Nov 2019


  • Active power decoupling
  • automatic power decoupling
  • buck power-factor-correction (PFC) rectifier
  • three-level flying capacitor

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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