Single-phase synchronous active front-end for high power applications

In this paper, the authors propose an efficient control technique applied to an active front end (AFE) topology. It is composed of n parallel-connected two-level single-phase ac-dc boost converters, with common de-link capacitor. In order to improve power quality and the performance in high power high speed train applications, the converters are synchronously driven. This proposed system is called SAFE (synchronous active front-end). The converters are used as unitary displacement power factor (DPF) ac-dc PWM rectifiers. This solution guarantees the ripple cancellation on the ac side and higher switching frequency respect to single AFE solution. The whole system can successfully manage the well known trade-off between high power handling and high switching frequency, with regard to utility side effects.