Single-stage single-switch isolated PFC regulator with unity power factor, fast transient response and low voltage stress

M. H L Chow, Y. S. Lee, Chi Kong Tse

Research output: Chapter in book / Conference proceedingConference article published in proceeding or bookAcademic researchpeer-review

14 Citations (Scopus)


In this paper a simple control method is presented for a single-stage single-switch isolated PFC regulator that can simultaneously achieve unity power factor and fast output voltage regulation, while keeping the voltage stress of the storage capacitor low. The converter topology comprises essentially a cascade combination of a discontinuous-mode boost converter and a continuous-mode forward converter. The proposed control utilizes variation of both duty cycle and frequency. The role of varying the duty cycle is mainly to regulate the output voltage. Changing the frequency, moreover, can achieve unity power factor as well as low voltage stress. Basically the switching frequency is controlled such that it has a time periodic component superposed on top of a static value. While the time periodic component removes the harmonic contents of the input current, the static value is adjusted according to the load condition so as to maintain a sufficiently low voltage stress across the storage capacitor. The theory is first presented which shows the possibility of meeting all three requirements using a combined duty-cycle and frequency control. An experimental prototype circuit is presented to verify the controller's functions.
Original languageEnglish
Title of host publicationPESC Record - IEEE Annual Power Electronics Specialists Conference
Number of pages7
Publication statusPublished - 1 Jan 1998
EventProceedings of the 1998 IEEE 29th Annual Power Electronics Specialists Conference, PESC. Part 2 (of 2) - Fukuoka, Japan
Duration: 18 May 199821 May 1998


ConferenceProceedings of the 1998 IEEE 29th Annual Power Electronics Specialists Conference, PESC. Part 2 (of 2)

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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