A Robust Sliding Mode Control Framework with Rapid Reaching Dynamics for PV-Battery-Based DC Microgrids

This paper proposes a high-performance nonlinear control strategy for transient voltage regulation in residential DC microgrids comprising photovoltaic (PV) and battery energy storage systems. A novel non-singular integral terminal sliding mode control with a rapid reaching law (NITSMC-RRL) is designed to tackle the challenges of low inertia, intermittent renewable generation, and bidirectional battery dynamics. The proposed controller introduces a dynamic fractional-order sliding surface and an exponential reaching mechanism to ensure fast convergence, improved robustness, and minimized chattering. Detailed mathematical modeling is performed for a dualconverter architecture integrating a PV-side boost and a batteryside bidirectional buck-boost converter. The control objectives include indirect voltage regulation and coordinated power flow. The effectiveness of the NITSMC-RRL controller is validated through MATLAB/Simulink simulations under varying load and solar conditions. Comparative results with existing nonlinear controllers including backstepping (BS), conventional sliding mode control (SMC), and double integral SMC (DISMC) - demonstrate superior dynamic performance, achieving the lowest overshoot (0.47%) and fastest settling time (0.03 s). The proposed approach ensures voltage stability, power balance, and system resilience under practical operating disturbances.