Transform and Stability Analysis of Nonlinear Time-Varying Control System

The boiler thermal control system is well known with the characteristic of slow time-varying, large lag and large inertia. Adopting generalized Jordan block and algebra equivalence transform method, all of the transfer functions at different load points is transformed to state-space description with time variable. According to engineering practice of control strategy based on incremental function observer and combined PID, the stability robustness is studied and present some corresponding infers. The simulation and engineering have testified the correctness of theoretical analysis and steady robustness of the system.