Research And Realization Of Energy-saving Control In VWV Air-conditioning System

At the time we are advocating low-carbon life, the country and people pay great attention to the problem of energy conservation. Central air-conditioning is a kind of large power equipment, and its energy consumption accounted for 60% of the building energy consumption. It often works under part load operation and causes unnecessary energy losses. Aiming at these problems, the energy-saving control for variable water volume air-conditioning system is studied and the design of controller is complished.The purpose of VWV is designed to make the cold of cold source output flow match with the cold of end that often changes required that can save the cold transfer and the costs of cold source operating. In this paper, the research object is a primary pump VWV system. Through the adjustment of the pump power frequency to change speed, so as to regulate the amount of water. The fuzzy PID composite cascade control system based on Smith predictive estimate is adopted in the system. There are two controlled variables:differential pressure of the most unfavorable position and the temperature of the cold source side. The main controller parameters is the temperature of retured water. Fuzzy PID controller of automatic preference is adopted in main controler. The minor loop's parameters is differential pressure, and Smith predictive estimator is adopted to eliminate the pure delay and improve the response speed of the system. According to the specific application of the VWV system, the least system design, A/D and D/A conversion and basic peripheral interface circuits are complished by stuy of LPC1314(ARM) base on Cortex-M3 core. The part of software complete the basic algorithm design process.A Simulation study about based on Smith prediction with fuzzy PID cascade control is made in Matlab, it shows that the parameters self-adjusting fuzzy PID controller based on the Smith predictive compared with general PID controller has smaller overshoot, faster response speed, higher steady accuracy, and excellent static and dynamic performance.