Input impedance and current feedforward control for leading-lagging phase admittance cancellation in the AC-DC boost converter

This paper introduces an input impedance and current (IIC) feedforward control with leading-lagging phase admittance cancellation (LLPAC) for ac-dc boost converter applications requiring higher efficiency and higher power quality. Whereas the conventional voltage feedforward method guarantees its ideal input admittance by generating average switch voltage effectively under well-regulated current compensator, the proposed IIC method contains an extra compensation term reducing the effects of external input parameters as well as an average switch voltage, resulting in improving input power quality in low switching frequency and high line frequency applications. Consequently, the proposed method allows obtaining more constant input admittance in both regions of leading and lagging-phase. In order to compare three different control approaches, the small-signal input admittances of the ac/dc boost converters are modeled and analyzed. A MATLAB/Simulink model and a 1.2kW dual boost PFC prototype board controlled by a digital signal processor are implemented to demonstrate the effectiveness of the proposed IIC feedforward control.