Decentralized Active Disturbance Rejection Control of Mult-Active Bridge Converter Based on Cascaded Linear-Nonlinear Extended State Observer

With distributed energy and DC distribution development, multi-active bridge (MAB) converters get attention because of their scalability and high power density. The communication-free decentralized MAB is superior to the traditional centralized MAB in modularity and flexibility. This paper proposes a novel active disturbance rejection control based on cascaded linear-nonlinear extended state observer (CLNLADRC) for the decentralized MAB. The method employs a preceding-stage linear observer to ensure system stability and a nonlinear observer to improve the tracking speed and estimation accuracy of the disturbance. The system's stability, anti-disturbance sensitivity, and noise sensitivity are analyzed. Compared with the typical PI control and linear active disturbance rejection control (LADRC), the output ports' transient voltage peak and voltage regulation time are reduced, and the load step mutation resistance of decentralized control is improved. Simulations are completed and compared to verify the control effectiveness.