Nonlinear measure of a boiler-turbine unit

Nonlinearity measure is proposed via the gap metric in this paper, and the concept is applied to a boiler-turbine unit to analyze its dynamics. It is shown that the system shows severe nonlinearities, and choice of a good operating range can help avoid the nonlinearity. Despite the nonlinear dynamics, it is shown that the controller constraint is another important factor of system nonlinearities, which can be compensated using some simple antiwindup techniques. Finally, some simulation results are given to verify the conclusions.