An Efficient Photovoltaic Energy Harvesting System Using MPPT Control Based on Partial Open‐Circuit Voltage Sampling

ABSTRACT This paper proposes an efficient photovoltaic energy harvesting (PVEH) system suitable for indoor lighting conditions and employs a maximum power point tracking (MPPT) control strategy based on partial open‐circuit voltage sampling (partial OCV sampling). The photovoltaic (PV) cell in the system consists of a single photodiode (PD1) and a sub‐array consisted of n − 1 photodiodes connected in series (denoted as PD( n − 1)). During the MPPT time, only the open‐circuit voltage (OCV) of PD1 is sampled. By utilizing the area ratio between PD1 and PD( n − 1), the equivalent OCV of the entire PV cell is estimated, enabling the tracking of the maximum power point (MPP). This method avoids the energy loss caused by sampling the OCV of the entire PV cell, as required in conventional methods. A prototype system was tested under various indoor lighting conditions. Experimental results show that the system can generate an output power ranging from 10.86 to 616.2 μW across the tested lighting levels, while the system's own power consumption is approximately 126 μW. Moreover, when the lighting intensity reaches a certain threshold, the system achieves self‐powered operation, indicating strong potential for practical applications.