Universal active disturbance rejection control for non‐linear systems with multiple disturbances via a high‐order sliding mode observer

This study is concerned with the output feedback control design for a class of non‐linear systems subject to multiple sources of disturbances/uncertainties including parameter perturbations, complicated non‐linear dynamics and external disturbances. By developing the high‐order sliding mode observer, both state and disturbance observations are incorporated into the controller design. By means of the lumped disturbance estimation as well as virtual state estimations, a composite output feedback controller combined with an additional feedforward compensation is proposed. The stability of the closed‐loop system is rigorously demonstrated based on Lyapunov stability criterion. Application of the proposed approach to a single‐phase DC–AC inverter system is finally implemented with experimental results to validate the feasibility and effectiveness.