<![CDATA[Post-harvest drying is a critical stage in determining coffee bean quality, yet small-scale farmers still largely rely on conventional sun drying, which is highly weather-dependent. This study focuses on the design and performance analysis of a Maximum Power Point Tracking (MPPT) algorithm using the Perturb and Observe (P&O) method on a buck-converter-based Solar Charge Controller (SCC) for a small-scale off-grid coffee bean drying system. The energy source is a 30 Wp Maysun Solar MS30M-36 monocrystalline panel charging a 12V 8Ah VRLA battery, with duty-cycle control executed by an Arduino UNO microcontroller using a four-branch decision-tree logic based on ΔP and ΔV readings. The design was validated through PSIM simulation prior to hardware testing. Simulation results show the P&O algorithm locks the panel operating voltage at 18.30 V (close to Vmp) within a tracking time of approximately 0.035 s, raising the output power from 22.00 W to 30.80 W (a 40.0% increase) compared to a static duty-cycle system. Real-world hardware testing shows the P&O MPPT system maintains the panel voltage within 16.63 V–16.97 V with a peak input power of 25.96 W and an average converter efficiency of 86.73%, markedly outperforming the non-MPPT system, which only reached a peak power of 17.02 W. These results confirm that the P&O algorithm significantly improves photovoltaic power extraction efficiency and is feasible for small-scale off-grid coffee bean drying applications.]]>
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