Análise de SRF-PLL e DSOGI-PLL Aplicados em um VSC Quatro Fios Conectado à Rede Elétrica com Desequilíbrio de Tensão

Abstract

The three-phase four-wire VSCs voltage source converters are used to connect sustainable sources to the distribution system where the loads are predominantly single-phase. The three-phase distribution system with unbalanced neutral has unwanted negative and zero sequence components. In this condition the synchronism between the VSC and the electrical grid that is done using the PLL (Phase Locked Loop) is affected. SRF-PLL (Synchronous Reference Frame-PLL) is popularly used, however it does not perform well in unbalanced systems. DSOGI- PLL (Dual Second Order Generalized Integrator-PLL) ensures synchronism between the VSC and the unbalanced power grid. Thus, the purpose of this article is to evaluate the effect of imbalance in ac currents of the VSC using the SRF-PLL and DSOGI-PLL