Research Of A Novel Fuzzy Logic Control Algorithm For A Direct Expansion (DX) Air-conditioning (A/C) System

Appropriately controlling humidity is important for developing a comfort indoor environment.The temperature-only control,which is commonly seen in most direct expansion(DX)air-conditioning(A/C)systems,cannot meet the requirements of thermal comfort.It is hard to add independent dehumidification equipment into DX A/C systems with compact structure,hence software-based decoupled(SWBD)temperature and humidity control methods are more applicable for these systems to realize simultaneous temperature and humidity control.Weights-based fuzzy logic control algorithm(WBFLCA)is a useful SWBD temperature and humidity control method for DX A/C systems,which has been successfully tested in an experimental DX A/C system.However,the weights,which are essential parameters of the control algorithm,needed to be tuned by amounts of trial tests.Since no criteria for setting the weights has ever been developed,it is hard to apply the algorithm in other systems.Basic setting modes for the weights are proposed in this paper.These modes are analyzed by control simulation and experiments to find out those have good control performance.A multi-function experimental DX A/C system is built to carry out experiments.Firstly,four combinations of setting modes of control for the single parameter is simulated to get the response curves of a first-order system.The control performance of the four combinations are tested by using the heater and humidifier of the experimental DX A/C system.The simulation can be verified by the experiments,which shows the feasibility of finding the criteria for setting the weights from the proposed modes.Then,a coupled temperature and humidity control model of a DX A/C system is built to simulate the control performance of sixteen combinations of setting modes for weights of WBFLCA applied for simultaneous temperature and humidity control.The result shows four of these combinations have better control performance and so that can be applied as the start point of weights tuning for real control systems.Three combinations are selected to carry out control experiments.The experimental results can verify their respective simulation,which means the setting rule derived from the simulation is reasonable to apply.Finally,the operating reserve of aggregated A/C systems under WBFLCA control is simulated using a group control model.The possibility of using direct frequency control to realize continuous demand response of aggregated A/C systems is also discussed in the final part.