Design of High Current Tracking for Pulsed-Coil Power Supply Based on Cascaded Linear Active Disturbance-Rejection Control

To suppress magnetohydrodynamic (MHD) instabilities during tokamak plasma experiments, this study designs a pulsed-coil power supply capable of four-quadrant operation and delivering a single-module output current of ±2.66 kA. However, the presence of the integral term in a conventional proportional–integral controller limits the achievable current slew rate and leads to suboptimal current sharing when multiple power supply modules operate in parallel. To address these issues without relying on a detailed mathematical model of the power system, a cascaded linear active disturbance-rejection control (CLADRC) strategy is proposed by leveraging the inherent decoupling advantages of the conventional linear active disturbance-rejection control (LADRC). The proposed design employs two cascaded extended state observers to estimate the lumped disturbances of the power supply and incorporates these disturbances as new system states for feedback compensation. Frequency-domain analysis demonstrates that the proposed control scheme achieves higher accuracy and faster disturbance estimation compared with traditional ADRC. Experimental results further verify that the CLADRC strategy not only satisfies the relevant technical requirements but also significantly enhances the dynamic performance of large-current tracking and improves current sharing among multiple parallel modules, outperforming both traditional proportional–integral (PI) and ADRC strategies.