“…However, sometimes this type of model is not sufficient and flexible enough to catch the key dynamic characteristics of complex system under diverse operating conditions. For instance, Gralda and MacArthur (1992); Li et al (2008); Rasmussen and Larsen (2009) have discovered that system parameters, such as the system gain, time-constant and time-delay, in a standard FOPDT formulation of the transient superheat dynamic can be time-varying. In order to keep the FOPDT model's merit, but, meanwhile be able to correctly reflect system's key transient dynamics, Sun and Yang (2011); Yang and Sun (2011) proposed a type of nonlinear FOPDT model, named Time-Varying FOPDT (TV-FOPDT), to model the transient superheat dynamic in a refrigeration system.…”