Enhanced Stability and Control of Solar Powered EV Charging Stations Using Disturbance Observer-Based Adaptive Sliding Mode Control for DC Voltage Stabilization

Electric vehicle Charging stations are essential for the growing number of EVs, requiring efficient integration of renewable sources, battery storage, and grid connections to enhance sustainability. However, connecting these components to a DC bus can cause DC bus voltage instability due to fluctuating power sources and varying load demands. Starting with the design of a second-order disturbance observer (DOB) aimed at estimating and counteract matched and mismatched disturbances. An adaptive sliding mode control (SMC) is then introduced. This enables the creation of a DOB-based adaptive SMC scheme, which manages the overall disturbances of the system. To address the chattering issue, a barrier function based SMC (BFSMC) approach is proposed. The distinctive aspects of this BFSM control approach is its capability to stabilize the designed sliding variable to a predefined neighbourhood around the origin within a limited duration, eliminating the need for prior understanding of the maximum limit of the lumped disturbance. The stability of the proposed control system is determined using the Lyapunov candidate function. The robustness of the controller is validated by comparing it to traditional control strategies like PID, Lyapunov and sliding mode controllers. The proposed method demonstrates superior performance in regulating DC bus voltage.