Input Voltage Feedforward Active Damping-Based Input Current Harmonic Suppression Method for Totem-Pole Bridgeless PFC Converter

Grid-side current harmonic (GCH) is an important issue in totem-pole bridgeless power factor correction (TBPFC) converters. In this article, a GCH suppression (GCHS) method based on input voltage feedforward active damping is proposed. First, an admittance model of the TBPFC converter considering the electromagnetic interference (EMI) filter and the time delay of the digital control system is established. The damping characteristics of the system are improved by constructing a virtual admittance, which does not require additional current and voltage sensors. Based on the admittance model analysis, the active damping can be matched and adapted to a wide power range. Through the extraction of harmonic information and the combination with current setting and modulation voltage information, the suppression of current harmonic under different loads can be realized. Besides, the sensitivity of the system parameters is analyzed. The system delay, load change, and system parameter change are considered in the design of active damping, so the current harmonics can be effectively suppressed in a wide power range. Finally, the effectiveness and feasibility of the proposed method are verified by experiments on a TBPFC converter platform.