Study on a Control Method of the Vacuum System Based on Regulating Valve

摘要

With the promotion of vacuum technology application,vacuum systems are applies in more and more fields. It is particularly important that the control of vacuum stability in some fields such as vacuum freeze-drying,vacuum coating and vacuum metallurgy. In this article,based on the basic evacuation equation of vacuum systems,a simplified model of vacuum system is set up. Combining the knowledge of control theory,the control method of vacuum degree in vacuum system based on regulating valve is modeled,calculated and analyzed. It comes to the conclusions: First,automatic regulation method improves the accuracy and efficiency of pressure control;Second,when the vacuum chamber is interfered by step signal,the system regulating time by this method is much shorter than by the system selfadjustment;Third,pressure adjustment error of the vacuum system based on regulator changes a little along with time. Therefore,only PI control is all right when the PID control algorithm is adopted. The conclusions of this article are suitable for the automatic control of vacuum chamber pressure in the low and middle vacuum ranges.