Disturbance supression improved discrete sliding mode fast current tracking control of experimental advanced superconducting tokamak fast control power supply

Abstract

SummaryThe output current of the fast control power supply for the Experimental Advanced Superconducting Tokamak (EAST) excites the load coil. Magnetic field can be quickly generated by the fast output current to control the balance of plasma vertical displacement. In order to improve the output current speed of EAST fast control power supply and its ability to resist external disturbance, an improved discrete integral sliding mode control method combining gray prediction and variable gain sliding mode observer is proposed. A sliding mode disturbance observer is used to observe the total disturbance on the load side, and feedforward compensation control is performed on the total disturbance. To further suppress chattering and accelerate convergence speed, a high‐order term is added to the traditional discrete exponential reach law, and a gain adaptive observer is designed to adaptively adjust the observer gain based on the observed current error and the tracking current error. In the current sampling process, an improved gray prediction structure is added, and the original current sequence of gray prediction is improved based on the principle of new information priority, improving the accuracy of predicted current, compensating for the inherent delay in digital control, and further improving the output current response speed. Simulation and experimental verification show that the proposed disturbance suppression improved discrete integral sliding mode fast current tracking control strategy has faster output current response speed and strong antidisturbance performance.