Modelling of solar PV-fuel cell based micro-grid system and harmonics mitigation using fuzzy controlled dynamic voltage restorer

Renewable energy sources are increasingly preferred for power generation due to their environmentally friendly processes. Micro-grids, in particular, have gained significant traction in the energy market for their reliability and sustainability benefits in distributed systems. However, grid-interactive systems are often subjected to disturbances caused by system-level faults and external factors. Both symmetrical and unsymmetrical faults, especially under harsh environmental conditions, can lead to equipment failures and even complete system blackouts. To enhance reliability and efficiency, hybrid renewable energy systems have emerged as optimal solutions for sustainable energy production. The rising use of power electronic converters in industrial and household applications, however, introduces severe power quality issues. This paper analyzes the dynamic performance of a micro-grid system comprising solar Photovoltaic (PV) and proton exchange membrane fuel cell (PEMFC) technologies under symmetrical and unsymmetrical fault conditions. Here, voltage compensation is achieved using the dqo algorithm. To mitigate harmonic distortions, a custom power device with an intelligent controller is considered more efficient and cost-effective. In the proposed hybrid micro-grid, a fuzzy controlled dynamic voltage restorer (FC-DVR) is employed for harmonic mitigation, implemented through a pulse width modulation (PWM) generator using MATLAB/Simulink models. The effectiveness of the FC-DVR on power quality improvement is assessed based on total harmonic distortion (THD). Simulation results under various fault conditions, such as line to ground (LG), line to line (LL), double line to ground (LLG), and three-phase (LLL), demonstrate that while a conventional dynamic voltage restorer (DVR) reduces THD by up to 26%, the FC-DVR achieves a reduction of up to 51%. This highlights the FC-DVR's ability to mitigate voltage harmonics and significantly enhance power quality. The FC-DVR has been demonstrated to be an effective controller for mitigating harmonics in hybrid micro-grid environments.