High frequency positive/negative pulse charger with power factor correction

Most fast battery chargers involve some form of pulse charging where a short high current charging pulse is followed by a rest period and in some cases a very short discharging pulse. In this paper, The first flyback power stage is used to generate the regulated output voltage with electrical isolation. The second power stage is a bi-directional Buck/Boost converter which can generate positive/negative charging pulse. In addition, the regenerative energy generated at the positive charging mode is feedback to the capacitor in series between the rectification bridge and filter capacitor. The power factor of the fast charger system is improved based on the energy feedback. Finally, the experimental results are developed to verify the proposed scheme.