A Scheme for Improving Input Current Zero-Crossing Distortion of Single-Phase Power-Factor-Correction Converters

Input current distortion at the zero-crossing of the input voltage is a general problem in power-factor-correction (PFC) converters, and it becomes more serious as the line frequency increases. This paper analyzes the zero-crossing distortion, and points out that the major causes are the low rising slope of the inductor current at zero-cross and the phase displacement between the input current and the line voltage. Since the boost multi-level (ML) converter can reduce the inductor and increase the equivalent switching frequency, it is adopted to PFC topology to reduce the distortion at high line frequency, which is verified by the simulation results. A boost three-level (TL) PFC converter is tested in the lab, the experimental results shows it has the potential to apply in the future variable frequency AC airborne system ranged from 360 Hz to 800 Hz