  Since proportional-integral-derivative (PID) controllers absolutely dominate
the control engineering, numbers of different control structures and theories
have been developed to enhance the efficiency of PID controllers. Thus, it is
essential and inspiring to operate different PID control strategies to the
PID2018 Benchmark Challenge. In this paper, a novel control strategy is
designed for this refrigeration system, where a feedforward compensator and a
conditional integrator are utilized to compensate the disturbances and remove
the steady-state error in the benchmark problem, respectively. The simulation
results given in the benchmark problem show the straightforward effectiveness
of the proposed control structure compared with the existing control methods.
