Autotuning of Digitally Controlled Boost Power Factor Correction Rectifiers

This paper presents a robust autotuning technique for digitally controlled boost power factor correction (PFC) rectifiers. The proposed tuning approach perturbs the PFC current and voltage control loops through injection of digital perturbation signals, and achieves the desired crossover frequencies and phase margins for wide ranges of operating conditions and power-stage parameters through simple compensator gain adjustments. An added benefit of the proposed approach is a precise estimation of the filter inductance and capacitance values, therefore facilitating accurate continuous/discontinuous conduction mode (CCM/DCM) boundary detection, which minimizes transition effects and further reduces the input current harmonic distortion. The proposed approach is verified by experimental results on a 300-W digitally controlled boost PFC rectifier prototype.