Genetic optimization algorithm on PID decoupling controller for variable flow heating system

Heating systems are used in homes and apartments worldwide. The variable flow system is advantaged to the energy saving while the control in variable flow system is difficult. This paper describes the typical variable flow heating system and presents the coupling mathematical model of heat exchanger. Based on the mathematical model, a new multivariable PID decoupling controller is proposed. This controller consists of diagonally matrix method-based decomposition compensatory unit and PID controller. To obtain better performance in the control system, an improved genetic algorithm is adopted to optimize the PID parameters in floating point representations. The population mutates before crossover in the computing process of the improved genetic algorithm, which is benefit to the convergence. To solve the slow convergence during the later evolution, the micromutation algorithm is adopted. The simulation results show that the decoupling control system is effective and feasible. The method can overcome the strong coupling features of the system and has better performance.