Cascaded AC-DC parallel boost-flyback converter for power factor correction

A two-stage power factor correction (PFC) topology achieves a higher
power factor quality and lower harmonic distortion than a single-stage
converter. This paper introduces a two-stage PFC topology using a parallel
boost and flyback converter which is employed as a voltage regulator The
main boost converter is used for PFC and the other is the active filter circuit.
The filter is implemented to improve the quality of phase-current and
eliminate the switching loss. Furthermore, a reaction curve of
Ziegler-Nichol’s method determines the controller parameter for cascaded
PFC converter circuit. Simulated and experimental results are presented to
validate the proposed method. The total harmonic distortion (THD) value
decreases significantly from 83.35% become 0.98% in the simulation. In
addition, experimental results show that the current response has good
performances, including less harmonics, higher power factor, and lower
THD value compared to without a PFC circuit. The PF increased from 0.43
become 0.96, the THD value decreased from 49.4% become 16.2%, and
contains a small number of harmonics. The proposed controller method has
better responses than the conventional one, including small steady-state
error, fast rise time and settling time. A microcontroller (MCU), type
STM32F407VG, produced by STMicroelectronics is used to execute the
proposed control in both converters.