Design Of Silicon Valve Controller And Research On Its Control Performance For Refrigeration System

With the rapid development of new energy vehicles, the market demand for air-conditioning systems of new energy vehicles will also be rapid development. Using reasonable control strategy in the application of silicon expansion valve(SEV) in refrigeration system can effectively reduce energy consumption, improve the operating efficiency of the unit. So the research for SEV in refrigeration systems can promote the development of new energy vehicles. Its also has far-reaching significance for environmental protection and sustainable development of the society.This paper investigates the SEV, SEV controller and control algorithm current development at in the world. It analyzes the principle of the refrigeration system, the function of its various important parts, the working principle of SEV, its advantages and the working principle of SEV controller. On this basis, the SEV controller was designed and developed. The hardwa re design includes MCU control module, power module, analog acquisition modules, SEV drive module and communication module, etc. The software design consists of the main program, initialization, analog acquisition, system status control, serial port interrupt service, the control algorithm, etc.The experimental platform of refrigeration system was designed to verify the control performance. On the basis of the general automotive air conditioning and refrigeration systems, it carries a lot of corresponding improvements including data acquisition, industrial control computer, a variety of sensors and actuators, etc. supporting monitoring software was programmed for the SEV controller which bring great convenience for the research of control Strategy.Final analysis starts from the minimum stable superheat mechanism, introduced minimum stable superheat curve. The control strategies which based on the theory of minimum stable superheat was obtained on the basis of experiments. By analyzing and comparing between the experimental data of PID algorithm, and fuzzy algorithm, it proposed parameters adaptive fuzzy-PID control algorithm. Through self-designed controller and refrigeration platform, a large number of experiments were done, showing that the superheat can b e well controlled with the control accuracy at ±1℃.