A novel control concept for operating a two-stage a-rectifier-based telecommunications power supply module under heavily unbalanced mains voltage conditions

In this paper, a novel control concept for a unity power factor three-phase AC/DC two-stage telecommunications power supply system is proposed. The system is formed by an input-side delta-connection of three single-phase modules with parallel connected DC outputs. The control concept features output voltage control, module load sharing and mains voltage proportional guidance of the input currents and does allow to continue in operation also in case of heavily unbalanced mains voltage condition like those given for a missing mains phase or in case of an earth-fault of a mains phase or for a short circuit between two mains phases.