| Popis: |
In this paper, a modified integral sliding mode controller (ISMC) is proposed for non-minimum phase dc-dc converters. A boost dc-dc converter operating in continuous conduction mode (CCM) is chosen as a representative case study. The converter’s bilinear model and its effect on the controller design necessitate the need for a nonlinear controller. Unlike a recently introduced ISMC, the proposed controller does not need a priori knowledge of initial conditions such as inductor current or capacitor voltage, nor does it implement a sign function to ensure a fast response or reachability. A novel modified sliding surface which ensures reachability, stability and reduces chattering at the steady-state operation point is proposed. Moreover, the proposed controller in conjunction with a disturbance observer (DO) enables the converter to maintain stable operation under disturbances and uncertainties. The system’s robustness against drastic, discontinuous, autonomous, or non-zero derivative disturbances are enhanced by including an invariant saturation function. The performance of the proposed ISMC is tested and compared with a well-established linear controller to prove its validity under different types and levels of disturbances and uncertainties. |
