High Power Three phase four wires Synchronous Active Front-End

In this paper, the authors propose an efficient control technique applied to an innovative three phase four wires active front-end (AFE) topology. It is composed of n parallel-connected two-level three phase AC-DC boost converters, with common DC-link capacitor. In order to improve power quality and performance in high power applications, the n converters are synchronously driven. This proposed system is called SAFE (synchronous active front-end). These converters are used as unitary displacement power factor (DPF) AC-DC PWM rectifiers. A central point technique control by a four-wires AFE is also presented. This solution guarantees the ripple cancellation on the AC side and a higher switching frequency respect to single AFE solution. The overall system can successfully manage the well known trade-off between high power handling and high switching frequency, with regards to utility side effects