HSS Modeling and Stability Analysis of Single-Phase PFC Converters

The frequency coupling and low-frequency oscillations are common challenges faced by PFC converters in data centers. To reveal their mechanism, this paper proposes the systematic harmonic state space (HSS) modeling of the single-phase PFC converters and conducts the stability analysis on that basis. The HSS model is based on the linear time-periodic (LTP) theory, which can accurately reveal the frequency-coupling interactions. Besides, the developed HSS model is validated by the frequency scan. The stability analysis is performed and is shown to be consistent with the simulation results. In addition, a SISO equivalent impedance model of the single-phase PFC converters is proposed considering the frequency-coupling dynamics and the interaction with grid impedance, based on the MIMO impedance model derived from the HSS modeling.