An Optimum Power Point Tracking Method for Thin-Film Solar Aircraft Embedded with Cascaded Converters

With the rapid development of thin-film photovoltaic (PV) technology, the application of solar-powered aircraft has become increasingly viable. The lightweight nature and high conversion efficiency of thin-film solar cells enable long-duration flight capabilities. However, as flight duration increases, challenges arise in maintaining a steady energy supply. Variations in sunlight intensity, coupled with shading caused by flight attitudes changes, can significantly hinder energy generation. While this issue can be mitigated using backup lithium batteries, the key challenge lies in determining the adequate reference voltages for cascaded PV sources the optimal timing for backup energy access. This paper proposes an Optimum Power Point Tracking (OPPT) algorithm to address this issue. The proposed OPPT algorithm efficiently manages the integration of solar power and backup energy, ensuring continuous power supply under varying flight conditions and sunlight availability. The performance of the OPPT method is studied under the switched-diode cascaded converter system, and experiments are carried out to verify its workability.