关键词: 变风量空调, 解析法, 解耦, PID控制

Abstract: In order to solve the problems such as numerous variables, serious coupling, large time delay and uncertain perturbations in variable air volume air conditioning, a decoupling PID control strategy based on analytic method is proposed. Models of the two coupling loops, air supply temperature and indoor temperature, are established, and also establishes the suitable desired closed-loop transfer function matrix. Thus the ideal expression form of decoupling controller matrix can be derived. Thereafter it is converted into PID form through Routh method for reducing order and one order Pade approximation. Performance requirements such as stability and robust stability are satisfied through adjusting the only regulatory variable according to amplitude frequency curves of spectral radius. Thereby the specific value of each parameter can be obtained. The results show that decoupling strategy based on analytic method can not only eliminate the coupling effect completely, but also has smoother tracking performance than that based on feed forward compensation, and less affected by uncertain perturbations.

Key words: variable air volume air conditioning, analytic method, decoupling, PID control