An Optimal Control Research Of The VRV Mini Central Air Condition System

VRV mini central air condition system with a multi-room refrigeration function, it can refrigeration allocation flexibility, saving installation space, and it costs less than the traditional investment, VRV mini central air condition system has become a commercial and residential air-conditioning industry mainstream. VRV mini central air condition system is connected by single compressor and condenser, and a number of evaporators and electronic expansion valves, forming a complex, multi-variable, strong coupling, and nonlinear system. How to achieve VRV mini central air condition system's variable capacity, variable flow control are the key issues and difficult problems for energy-saving control. Aiding by Shenyang Science and Technology item and the Education fund item of Liaoning province, this text is carrying on the optimal control method of VRV mini central air condition system.Firstly, this text analyzes working principle of VRV mini central air condition system, and analyzes the mechanism model of the inverter compressor, electronic expansion valve, evaporator and condenser.Secondly, this text gives control method as following: using fuzzy control strategy, and the equivalent temperature and the change rate of equivalent temperature as input of fuzzy controller, control the rotational speed of compressor, so that changing the refrigerant of refrigeration cycle, to meet the system's refrigeration of the room and the overall load matching; against the nonlinear and strong interference characteristics of superheat, based on determinate cooling capacity, designs an intelligent controller of superheat, for superheat in different evaporating conditions, using fuzzy control with variable region, regulating the opened degree of electronic expansion valve, realize the best control for each superheat of evaporator, so as to ensure stable operation and enhance EER of VRV air-conditioning system.Finally, does some simulation studies to the fuzzy controller with variable region that designs for electronic expansion valve, and compared with ordinary fuzzy controller. The results show that the control precision, the speed of reaching steady-state value and anti-interference and otherwise, the fuzzy controller with variable region can be superior to ordinary fuzzy controller.