Abstract: An improved topology is proposed here with forward flyback converter having PWM rectifiers at the input side in order to achieve unity power factor . Buck converter is inserted between the forward sub converter and load. Here “One and a half stage” converter scheme is proposed where most of the power reaches the load through flyback sub converter and a small portion through forward sub converter and buck converter. Electrolytic capacitor can be eliminated, thus the lifetime of driver can be improved. Bus voltage between forward sub converter and cascaded buck converter is auto regulated for achieving power balance. The proposed driver has higher efficiency than conventional AC-DC led drivers. Ripple compensation control is done in the proposed scheme. Hysterisis control is used for switching PWM rectifiers in order to improve the power factor and hence THD is reduced.  Proposed topology is very suitable for industrial application such as low power AC-DC led drivers.

Keywords: PWM Rectifiers, Forward - Flyback Converter, Power Factor Correction, Ripple Compensation, Hysteresis Control, THD (Total Harmonic Distortion)

| DOI: 10.17148/IJIREEICE.2019.7308