Segmented PID control method with multioutput compensation for electrode current in fused magnesia smelting process

To address the control difficulties arising from time-varying model parameters, significant nonlinear disturbances, and actuator saturation constraints in the electrode current of the fused magnesia smelting process, this paper proposes a segmented PID control method with multi-output compensation. By introducing a decomposition strategy combining a dynamic linearized model and nonlinear disturbance terms, the electrode current dynamics are characterized as a combination of linear dominant terms and high-order nonlinear disturbances. The nonlinear terms are dynamically compensated through a historical data-driven predictive compensator and an error feedback compensator. A segmented PID controller is designed to dynamically adjust the proportional, integral, and derivative parameters based on the tracking error amplitude. Simulation results demonstrate that when parameters such as molten pool resistivity and submerged arc height undergo unknown random variations, the proposed method strictly confines the three-phase electrode current tracking error within ±2000A, significantly improving control precision in the smelting process.