Gain margin and phase margin analysis of a nuclear reactor control system with multiple transport lags

A method for finding the boundaries of the constant gain margin and phase margin of control systems with transport lags and adjustable parameters is presented. The systems are first modified by adding a gain-phase margin tester, then the characteristic equations are formulated, and finally the stability equations are used to find the boundaries of the constant gain margin and phase margin. The main advantage of the proposed method is that it makes it possible to obtain complete information about the effects of adjustable parameters on the gain margin and phase margin and their corresponding crossover frequencies. In order to show the usefulness of the proposed method, a nuclear reactor control system with multiple transport lags is discussed as an example