Integral Sliding Mode Control of LCL Single Phase Photovoltaic Grid-Connected System Based on Sliding Mode Observer

In this research, we introduce an integral sliding mode control (ISMC) approach designed to improve the robustness of systems against parameter variations and external disturbances, thereby enhancing dynamic performance. For DC/AC converters, we developed an ISMC method with a sliding mode observer (SMO) to address the inherent resonance caused by LCL filters and reduce the negative impact of their parameter changes. The SMO, equipped with an adaptive switching function, estimates the inverter-side current and capacitor voltage of the LCL filter. This control strategy not only strengthens the system's resilience to parameter changes but also significantly decreases system chattering. Matlab/Simulink simulation results indicate that the proposed approach effectively mitigates various disturbances, ensuring the reliable operation of photovoltaic microgrids.