Humidity and temperature nonlinear control based on almost disturbance decoupling and state observers for air-handling units

The almost disturbance decoupling problem for air-handling units (AHUs) containing unmeasurable states is addressed. Firstly, a state observer is introduced to estimate the supply air temperature, which is an unmeasurable state. Secondly, the almost disturbance decoupling technique is utilized to attenuate the influence of unknown disturbances including outdoor temperature, outdoor humidity ratio, heat load, and strength of the humidity source. Finally, compared with the linearization and PID control methods, simulation results verify the superiority and effectiveness of the proposed controller.