Application of an intelligent PID control in heating ventilating and air-conditioning system

The controlled object in heating ventilating and air-conditioning (HVAC) system has large inertia, pure lag and nonlinear characteristic. The uncertain disturbance factors affect the control performance. This paper presents the control strategy of self-adaptive human-imitating intelligent PID control, which is adopted in the multivariable and strong couple nonlinear temperature system. Different PID control strategy, together with error observer for adjusting parameters online and control of feed-forward compensation, is adopted according to different error and its derivation to overcome the exoteric influence. At the same time, the control strategy of lag compensation is accordingly adopted in order to overcome the effect of lag characteristic in the air-conditioning system. The experiments and application in HVAC system show that the intelligent PID controller has some advantage such as strong robust, self-learning and self-organizing; especially the control algorithm is easy to program and apply the actual control system. The intelligent PID control is very effective and practical.