A Novel Variable On-Time Control Scheme for Boundary Conduction Mode SEPIC PFC Converter

Power factor correction (PFC) can be achieved by a single-ended primary inductor converter (SEPIC) operating in boundary conduction mode (BCM) with conventional constant on-time (COT) control, but it is challenging to achieve low total harmonic distortion (THD) and high-power (PF), particularly at high input voltage. A variable (VOT) control strategy for BCM SEPIC PFC without voltage feedforward multiplier circuits proposed realize unity PF this paper. By using slope sawtooth generator whose controlled the duty cycle of main switch adjust time power converter, VOT scheme use simple easy-to-implement circuit enhance decrease THD significantly, especially The simulation model 100W experimental prototype are built verify feasibility suggested method. Simulation experiment results demonstrated that novel remarkably enhances decreases affecting efficiency contrast COT control.