Nonlinear observer-based control for an active rectifier

In this paper, a nonlinear observer-based controller for a single-phase active front-end (AFE) rectifier is presented to improve power factor with high quality output DC voltage. Proposed algorithm is based on an Luenberger-like observer and a passivitybased controller. Closed-loop stability is demonstrated for all operating ranges using Lyapunov theory. Performance of observerbased controller is shown by simulation for voltage sag occurrence and abrupt load changes.