Research And Implementation Of Continuous Overload-operating Test System For Refrigerant Compressors

This paper mainly focuses on research and implementation of continuous overload-operating test system for refrigerant compressors, the system function is to test the heating circumstance of small type refrigerator compressors and working state of the overload protector in the certainly severe conditions. The characteristic of continuous overload-operating test system introduces the parallel alternative refrigeration system. It can independently control the working conditions of the work station.(1) This paper elaborates the test method and principle of continuous overload-operating test system for refrigerant compressors. According to the characteristics of the controlled plant, the parallel alternative refrigeration system is introduced to design the test system’s hardware structure taking Industrial Control Computer as control core in the measurement and system.(2) The paper also analyzes the working principle of alternative refrigeration system, establishes mathematic models of each heat-sending link of then subassemblies, including condenser, expansion valve and evaporator, and puts forward the control model of continuous overload-operating test system’s stable process.(3) The D/P conversion algorithm and the PID control algorithm of stepping motor is proposed to control the conditions of refrigeration system to stable in the acceptable region. The Least Squares Method and Optimization Piecewise-Linear Algorithm are used to linear treatment of the sensor. Median and mean filter algorithm is used to eliminate the offset of sampling values caused by pulse interference.(4) The upper software adopts both object-oriented technology and design pattern with Unified Modeling Language (UML) and Delphi-based development platform.(5) The hardware and software of system are debugged. The paper also gives out some further research problems on the basis of the experimental data.This test system has been in operation for more than a year, the results of operation prove that it is stable, reliable, and major qualification of this system catches the advanced level of the domestic.