Analysis, Design and Control of a Unified Power-Quality Conditioner Based on a Current-Source Topology

This paper presents a three-phase unified power-quality conditioner based on current source converters (CSC-UPQC), including the design guidelines of the key components, an appropriate control scheme, and a selection procedure of the dc current level. Particularly, the ride through capability criterion is used to define a minimum dc current level so that the CSC-UPQC achieves the same characteristics as a UPQC based on voltage-source converters in terms of voltage disturbance compensation in the point of common coupling (PCC) and load power factor compensation. A 1.17 MVA load fed from a 3.3 kV system is used to show the proposed design procedure, and a laboratory prototype is implemented to show the system compensating sags and swells using low switching frequency in the CSC and maintaining a unitary displacement power factor in the PCC.