Research on Buck Converter Based on Double Close-Loop ADRC

Aiming at the problems that conventional PID control is struggle to model complex control objects and is not easy to set parameters, this paper proposes a double closed-loop active disturbance rejection control (ADRC) based on BUCK converter. ADRC has almost model-independent characteristics and has no accurate mathematical model requirements for control objects. Firstly, the second-order transfer function fitting of the current inner loop control object is carried out. Secondly, the fitted graph is combined with the bandwidth method to design the control parameters of ADRC. The parameter setting and design of the voltage outer loop are processed as follows. The simulation results show that the maximum variation of the output voltage is 0.6 V and the maximum adjustment time is 0.3 ms under the step jump of the input voltage. When the output load suddenly increases or decreases, the time of the system to restore the steady state operation is reduced by an order of magnitude compared with the PID control, which reflects the superiority of the control structure in this paper.