Digitized Feedforward Compensation Method for High-Power-Density Three-Phase Vienna PFC Converter

This paper presents a front-end three-phase ac/dc power factor correction rectifier, which is based on the three-level bidirectional-switch Vienna topology. On one hand, the rectifier is designed to operate in continuous-conduction mode (CCM) at full power. However, at reduced load, it operates in discontinuous-conduction mode (DCM). On the other hand, with reduced input inductance, the DCM mode occurs even when the rectifier operates 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.