Research And Application Of Series-parallel Connection Lubricated Screw Compressors Control System

Experimental Advanced Superconducting Tokamak (EAST) is the first operating fully superconducting device for nuclear fusion experiments in the world. The cryogenic system supplies a cryogenic environment to keep the superconducting magnets in the steady and reliable operation. Cryogenic system comprises a compressor station, a helium refrigerator subsystem, a helium distribution system. Screw compressors is an important part of the cryogenic system. To realize automatic control of compressors has a great significance to economize energy, increase efficiency of the refrigerator and ensure the nuclear fusion experiment operate normally.Due to variables coupling, difficult-to-model, uncertainty and time lag of slide valve, the paper presents a novel control idea which combine expert control and regular Proportional-Integral-Derivative (PID) control. The 3 stage pressure control loops are expatiated detailedly. Simulation research is carried out based on system identification of pressure control loops. Also actual running effects are presented. The paper analyzes the automatic start scheme, automatic stop scheme and interlock protection of screw compressors. The paper lucubrates on the engineering tune methods of PID controllers. The application of limit loop automatic tune algorithm based on relay oscillation principle isemphatic expounded. Aim at actual loops of the compressors control system.At present the compressors control system has been already examined through three turn cool down experiment, whose movement was good condition.