Research on Multi-functional Grid-connected Inverter based on Enhanced Conservative Power Theory

Distributed generation grid-connected inverter has similar software and hardware structures as active power filter(APF), static var compensator(STATCOM) and other active compensation equipment. In this paper, an improved conservative power theory (CPT) algorithm is proposed to extract harmonics, unbalance and reactive load current without introducing phase-locked loop (PLL), considering the influence of distorted voltage of PCC. On this basis, a power quality compensation scheme based on the proposed algorithm is designed and applied to build a multi-functional grid-connected inverter with power quality management function. The effectiveness and compensation performance of the proposed scheme is verified through simulation results.