Virtual Admittance Reshaping Based Input Current Phase Shift Suppression Method for Totem-Pole Bridgeless PFC Converter

Grid-side current phase shift (GCPS) is an important issue in totem-pole bridgeless power factor correction (TBPFC) converters. In this article, a virtual admittance reshaping based GCPS suppression method is proposed based on the establishment of the admittance model of the TBPFC converter including the EMI filter. The virtual admittance reshaping does not need additional current and voltage sensors and can realize complex admittance through a control algorithm. Thus, the current phase error can be adjusted to zero with the optimal design. The inherent admittance of the system is analyzed from the perspective of system frequency characteristics to extract leading-phase admittance. Then, the parallel admittance is produced through the inductance current for canceling it. The current reference and the modulation voltage are combined to realize obtaining the equivalent virtual admittance and meanwhile reduce the burden of the current regulator. The sensitivity of the system parameters is analyzed, and the saturation effect of the inductor and the error of the EMI filter parameters have little effect on admittance reshaping. Besides, the research method does not need to adjust parameters according to the load. The effectiveness of the proposed method is verified by experiments on a TBPFC converter platform.