Series Buck–Boost – Flyback Converter as Power Factor Correction for Electric Bicycle Battery Charging

Abstract

The rapid transition toward sustainable electric bicycles offers green energy efficiency, yet the goal is frequently hindered by the poor power quality of conventional charging system. Specifically, the use of diode rectifiers for non-linear battery loads generates highly distorted input currents and degrades the power factor value. To overcome these critical operational  drawbacks, this paper considers the integration of a converter topology to achieve high Power Factor Correction (PFC) in battery charging application. The proposed system integrates a two-stage PFC topology in a series circuit of buck–boost and flyback converter. A buck-boost converter is used as a PFC converter in discontinuous conduction mode (DCM), ensuring that the input current and voltage waveforms are accurately in phase. Additionally, the flyback converter operates as a voltage regulator, providing a voltage output for the charging process. The simulation confirm, the series buck-boost – flyback converter sustain a constant output of 57.6 V and 1.4 A with constant current–constant voltage (CC-CV) mode using a Fuzzy Logic Controller (FLC). The results showed that the power factor increased from 0.73 without the PFC converter to 1 with the PFC converter, and the Total Harmonic Distortion (THD) value also decreased from 76.42% to 21.55% and contained fewer harmonics.