Structure optimization based on nonlinear methods for the coordinated control system of power units

To improve the load-following capability and to overcome the effects of nonlinear behavior, an optimizing coordinated control system has been developed for a typical nonlinear boiler-turbine unit model. The feedback linearization theory is used to deduce a pseudo-linear system of the model, and the two-degree-of-freedom control structure is adopted to guarantee the stability and tracking performance of the closed-loop system. The parameters of controller are tuned by comparing the closed-loop transfer function with an anticipant function. Because of the simple form of controllers (composed with proportion or integral), the optimizing coordinated control system can be realized in field easily. The system performance, load tracking, disturbance rejection, and robustness, are proved by simulation tests in different operating points.