A novel high-frequency digital PFC controller with second harmonic compensation

This paper presents improved control strategies and design methods for a high-frequency digital PFC controller. Anti-windup technique is introduced into both the current loop and voltage loop regulators in order to enhance the dynamic performance. The design methods of AW_PI regulators are discussed in detail. A steady-state second harmonic compensation method is presented to increase the control bandwidth of voltage loop, in order that contradiction between the steady-state and dynamic performance is diminished. As the frequency goes as high as 200kHz, the light load losses increase remarkably. A variable-period method is proposed so that the light load efficiency of PFC module is improved. A dual-boost PFC module with DSP controller is built. Experiment results show that the dynamic performance is improved and the steady state waveforms of input current and output voltage are desirable at both light load and full load.