Multilevel PFC Converter Based on Flying-Capacitor

This paper presents a multilevel PFC converter based on a flying capacitor design, which reduces voltage stress on MOSFETs and achieves three voltage levels using sinusoidal pulse width shift sinusoidal pulse width modulation (SPWM). This control method is simple, with the inductor current exhibiting a double-frequency ripple, contributing to improve the input current performance. A 500W prototype was developed, operating with a 110V AC input and delivering a 200V DC output with a power factor of 0.998. The lowest total harmonic distortion (THD) of the input current is 3.84%. Experimental results confirm the effectiveness and advantages of the proposed converter, making it suitable for off-line power supplies where stable DC output, and low THD are critical for optimal system performance and reliability.