Improving power factor correction in distributed power supply systems using PWM and ZCS-QR SEPIC topologies

The single-ended primary inductance converter (SEPIC) presents several advantages over boost and flyback topologies which make this converter convenient for use as a power factor preregulator (PFP). Due to this fact, both the pulsewidth modulation (PWM) and the zero-current switched quasi-resonant (ZCS-QR) SEPIC used as PFPs are studied. Stress in components and operation in continuous and discontinuous conduction mode are considered in the PWM case, while the use of full-wave and half-wave resonant switches is considered in the ZCS-QR case. The study of the PWM SEPIC used as a PFP reveals that both types of PFP control, multiplier approach and voltage-follower approach, can be used in PWM SEPIC, the first one when it operates in continuous conduction mode and the second one when it operates in discontinuous conduction mode. Regarding the ZCS-QR SEPIC used as PFP, both types of resonant switch (half-wave and full-wave) can be used