Uninterruptable capability for an active power line conditioner

摘要

A supplementary DC power source is coupled to the DC link circuit of an active power line conditioner (APLC) for sustaining uninterrupted AC power to a load during the time interval needed for AC power restoration or for an alternate or a back-up AC source to be brought on line to power the load upon temporary or continued failure of an AC power source. The supplementary DC source is comprised of a rectifier circuit across which is connected a storage capacitor. A boost converter and an auctioneer diode are coupled between the storage capacitor and the DC link circuit so that when the DC link drops in voltage in response to a sag in the AC source voltage upon loss of the AC voltage source, the necessary power is provided by the storage capacitor and boost converter. A pair of fast acting switches are also coupled between the AC source and the power bus feeding the inverters to isolate the AC source from the APLC and the load upon loss of the AC source. When the back-up AC source is required and comes up to voltage and is synchronized with the APLC, the fast acting switches are again closed to connect the back-up AC source to the APLC and the load.