Application of Fuzzy-PID Controller 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. Combined the fuzzy control and general PID control, the temperature and humidity of room are controlled in HVAC system of a TV building. In winter, the experiments were done in a big studio. The experiments included the change of the operation set point in the studio and the 24 hours´ control performance. The temperature of the studio was controlled through PID control, fuzzy control and fuzzy-PID control. Compared the three control algorithm, it is found that hybrid fuzzy-PID control has better adaptability and stability, less overshoot, faster response and higher precision than PID control and fuzzy control. The algorithm of fuzzy-PID control can reach the goal of comfort and energy saving. In addition, the threshold quantity in fuzzy-PID control affects the control performance so that the choice of valve is important