Nonlinear optimal control of air handling unit via State Dependent Riccati Equation approach

The Air Handling Unit (AHU) is used to provide clean air in the air conditioning systems that regulate both temperature and humidity to desired values. Because of nonlinear and complex nature of coupling between the air handling system variables, an effective control system confronts many challenges. Hence using an approach that can consider all the complexities of the dynamics model in terms of control process is impossible. In this paper, the State Dependent Riccati Equation (SDRE) approach is used for nonlinear optimal control of AHU system. In the proposed method, by using pseudo-linearization and maintaining all nonlinear features of system, optimal control law is produced for both stabilization and online output tracking. In addition, for tracking reference paths, the SDRE approach would be able to control effort and minimize the energy consumption. The SDRE approach is the state feedback control method. The simulation results show good performance of the SDRE method in the tracking reference paths despite the change of equilibrium point and disturbance in comparison with LQR.