Digital control of a single-stage single-switch flyback PFC ac/dc converter with fast dynamic response

Abstract

This paper presents the DSP control of single-stage single-switch (S4) flyback ac-dc converter with fast output voltage regulation. Active current shaping technique using flyback ac-to-dc converter has been employed for the power factor control and dc voltage regulation. The proposed control scheme possesses the following characteristics: high power factor, fast regulation of the output dc voltage, high efficiency, low cost, galvanic isolation, and the most important is that all the control functions are realized by using software control which provides great flexibility for system modification and applications. An adaptive voltage ripple estimator has been proposed to compensate the measured dc-link voltage ripples. The proposed control scheme for the S4-PFC flyback converter was realized by using a single-chip DSP controller. Simulations and experimental results have been given to illustrate the performance of the implemented DSP-controlled PFC converter.