Application of two-loop robust control to air-conditioning systems

This paper presents the design and application of a two-loop robust controller for temperature control in air-conditioning systems. A Takagi-Sugeno fuzzy model with uncertain local models is developed to describe the associated nonlinearities and uncertainties in the operation of the air handling units. Parallel distributed compensation is used to design the global control law. The local control law consists of two loops: an inner-loop integral controller and an outer-loop min-max predictive controller with short prediction horizon. A discounting scheme is developed to weight the contribution of the two loops. Experimental results are presented which show that the proposed strategy can achieve acceptable control performance with a minimum of onsite tuning. © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society.