Unified Active Disturbance Rejection Control Strategies for Time-Varying Disturbances: Case Study on a DC-DC Boost Converter

For time varying disturbances, it is reported that cascade extended state observer (CESO) as well as generalized proportional integral observer (GPIO) based active disturbance rejection control (ADRC) strategies yield satisfactory disturbance rejection whereas a linear extended state observer (LESO) fails to do so. Furthermore, including poles of the desired dynamics into the nominal model results in a simple and easy-to-implement reduced order observer. Also, manual tuning of ADRC parameters fails to provide optimal closed-loop system response. Motivated by the above facts, unified structures of CESO (UCESO) and GPIO (UGPIO) are proposed in this work and convergence analysis of the closed-loop system is presented based on the above mentioned control strategies using Lyapunov stability criteria. Additionally, particle swarm optimization (PSO) based optimal control strategies in the framework of above said ADRC schemes are also presented. Case study performed on a DC-DC boost converter illustrates superior disturbance attenuation, regulatory performance and reference tracking of the proposed control strategies.