Dynamic Model-Based Fault Tolerant Control of Variable Air Volume Air Conditioning System

A dynamic model-based fault tolerant control of a variable air volume air conditioning system is developed. State space model of the variable air volume air conditioning system is used to detect, isolate, and estimate stuck faults of the damper vanes of the air handling unit (AHU). Fault identification is implemented by an adaptive interactive multiple observer scheme. It has been shown analytically that observers representing faults in two mutually redundant variable air volume flow control boxes wrongly converge to the same value even when fault has occurred in only one variable air volume flow control box. An input modification scheme is proposed to prevent convergence of the observer corresponding to the functional variable air volume box. Using the information regarding the fault, its effect is minimized. This is achieved by applying the control distribution concept.