Integrated Maximum Power Point Tracking System for Photovoltaic Energy Harvesting Applications

The integrated circuits employed for power management in photovoltaic (PV) energy harvesting applications are required to perform an efficient maximum power point tracking (MPPT) process for maximizing the power production of the PV source during the continuously changing atmospheric conditions. Among the alternative MPPT methods, the perturbation and observation (P&O) technique has the advantages of operational and implementation simplicity. In this article, a novel PV MPPT control system for on-chip implementation of the P&O MPPT method is presented, which, compared to the past-proposed on-chip MPPT systems, has the advantage that it is implemented based on purely digital CMOS circuits without requiring the use of complex circuits, such as multipliers, sample and hold units, or analog-to-digital converters. Therefore, it can be easily implemented on-chip with low design complexity while simultaneously retaining the high-performance features of the P&O MPPT technique. The proposed PV MPPT system has been fabricated using the XFAB XH018 0.18-mu m CMOS technology. The experimental results verify the successful operation of the on-chip PV MPPT control unit and its ability to achieve a high MPPT efficiency over a wide range of operating solar irradiation values.