MODELING AND STABILITY ANALYSIS FOR PARALLEL OPERATION OF UPS WITH NO CONTROL INTERCONNECTION BASING ON DROOP CHARACTERISTIC

Abstract

The droop characteristic is an effective control scheme for the parallel operation of UPS systems with no control interconnection. This paper presents a small-signal model for two paralleled single-phase UPS systems with the droop control scheme. Basing on the proposed small-signal model, we have analyzed the influence of various parameters on the stability of paralleled systems, which gave guides for the design of the paralleled systems' parameters. The simulation and experimental results both confirm the validity of the proposed small-signal model.