A comparative analysis of control algorithms for three-phase line-interactive UPS systems with series-parallel active power-line conditioning using SRF method

This paper presents alternative control algorithms using synchronous reference frame (SRF) based controllers, which allow an effective power factor correction, load harmonic current suppression and output voltage regulation for three-phase line-interactive UPS systems with active series-parallel power-line conditioning capability. The proposed UPS systems are composed of two active power filter topologies. The first one works as a series active power filter and the other works as a parallel active power filter. An analysis of two control algorithms using SRF method, including compensation of the instantaneous real input power is carried out. The control algorithms are described, and next analytically studied to verify their characteristics. Digital simulations are presented to confirm their good performance