Reviews of methods to extract and store energy for solar-powered aircraft

Solar energy is considered to be the most reliable source in the future, and applying solar energy for flight is one of the most promising utilizations of renewables. Since the invention of solar-powered aircraft in 1974, the methods to extract and store energy for it have become the important research points all around the world. Currently, the main methods to do so are photovoltaic cell, rechargeable battery, and component of maximum power point tracking (MPPT). These years, many institutions and scholars have dedicated great efforts to the relative research. Besides, there are also several other methods in consideration, such as to extract energy from wind shear and store energy by gravitational potential. However, it is still not a simple task for the designers of solar-powered aircraft to select a particular technique from a number of existing techniques, since each technique has certain advantages and disadvantages with respect to different performance indices to fulfill the special requirements. Thus, the aim of this paper is to review in detail the working principle of different methods to extract and store energy, and to compare their performances on the basis of desirable features applied on solar-powered aircraft, and to provide some guidance principles for designers to select proper methods.