Design of a Nonlinear Optimal Controller for an Air Handling Unit in the HVAC System

Subject Areas : Journal of New Applied and Computational Findings in Mechanical Systems

Fariba Bouzari Liavoli ¹ , Hasan Karimi ²

1 - Department of Electrical Engineering, Qazvin Branch, Islamic Azad University, Qazvin, Iran
2 - Head of Electrical and Mechanical Engineering Department, Radin Control Alborz Company, Qazvin, Iran

Received: 2024-11-29 Accepted : 2025-01-12 Published : 2025-01-17

Keywords: HVAC system, Air Handling Unit, Pseudo Linearization, State-Dependent Riccati Equation, Constrained Input.,

Abstract :

Designing a nonlinear control system for an air handling unit is recognized as a challenging and difficult process due to the complexity and nonlinear characteristics, as well as the interaction among state variables of the system. Therefore, it is impossible to use a control approach that can take into account all the complexities of the dynamic model of the air handling system in terms of control processes. This research utilizes the state-dependent Riccati equation (SDRE) method to optimize the nonlinear control of the air handling system while considering input constraints. For this purpose, by employing the quasi-linearization method and maintaining all nonlinear characteristics of the system, an optimal control law for output tracking under constrained input conditions is designed. Additionally, this method is capable of tracking the reference path by controlling the reference signal while minimizing energy consumption. Simulation results indicate the high efficiency and effectiveness of this method in tracking reference paths, especially when the equilibrium point changes and constrained inputs are applied to the system. The state-dependent Riccati equation (SDRE) method can accurately and swiftly address various dynamic challenges and maintain system stability.

 

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