Estratégia de Paralelismo Baseado no Conceito de Impedância Virtual para Inversores Trifásicos a Quatro Fios

Abstract

The paper proposes a strategy for parallel connection of three-phase inverters, which can be applied in UPS (uninterruptible power supply). The control strategy is based on the virtual impedance concept, with no communication among the inverters. The proposed strategy is highlighted by its easy implementation that is similar to the conventional control of one inverter. The main features of the proposed strategy are modularity, fast dynamic response and good static regulation, even under load disturbances or hot-swap connection of inverters. The digital design implementation of the control strategy is described and experimental verification using two fourwires VSI modules with rated power of 6 kVA each are reported herein.