Digitized feedforward compensation method for high power density three-phase VIENNA PFC converter

This paper presents one front-end three-phase AC/DC power factor correction (PFC) rectifier, which is based on three-level bidirectional-switch VIENNA topology. On one hand, the rectifier, which is designed to operate in continuous-conduction mode (CCM) at full power, operates at reduced load, discontinuous-conduction mode (DCM) occurs in a zone which is close to the crossover of the line voltage. On the other hand, with the reduced input inductance, the DCM mode occurs even when the rectifiers operate at full power. In this paper, the digitized feedfoward compensation method is proposed for the rectifier to reduce the impact of the switch between DCM and CCM. The theoretical analysis of the proposed method is deduced, furthermore, the control design strategy is given. The experimental results are obtained by using a digitally controlled VIENNA rectifier, which validated the proposed compensation method.