Third Harmonic Current Injection-Based Three-Phase Two-Switch PFC Converter for Wide Power Range Operation

As conventional three-phase two-switch power factor correction (PFC) converters operate at continuous conduction mode, it is difficult to control the intermediate phase current effectively, which leads to distortion of the grid current. A novel three-phase two-switch PFC converter topology based on third harmonic injection is proposed in this paper to realize wide-power-range and low-harmonic operation. The third harmonic is injected through a resonant network to enhance the grid current quality. The impact of harmonic injection amplitude and resonant network parameters on the current quality of grid side is analyzed. The harmonic injection coefficient can be regulated in real time to ensure that the PFC converter meets harmonic requirements in a wide power range. The resonant network parameters are optimally configured according to the constraint condition of current harmonics and operating power, which can avoid the impact of increased neutral point voltage at the DC-link on the stable operation of the converter. Therefore, the harmonic distortion of the grid current can be significantly reduced, and the power factor can be improved. Finally, the effectiveness of the proposed converter topology is verified on the three-phase two-switch PFC converter prototype. Compared to the traditional method, the efficiency of the PFC converter can be improved by more than 2% while meeting international electrotechnical commission (IEC) 61000-3-2 harmonic standards.