# Power Sources for Unmanned Aerial Vehicles: A State-of-the Art
## 3 Conclusions
\begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Energy Sources** & **Architecture** & **Advantages** & **Limitations and Drawbacks** \\ \hline Fuel cell and battery & \begin{tabular}{c} The high energy and power \\ densities of the hybrid power \\ supply result in increased \\ endurance and faster response time. \\ This allows for efficient energy \\ generation and storage, enhancing \\ the overall performance of \\ the system. \\ \end{tabular} & \begin{tabular}{c} The use of a hybrid power supply \\ system leads to an increase in weight, \\ as additional components, such as \\ controllers and converters, are required \\ to manage the system. This introduces \\ added complexity to the UAV, further \\ contributing to the overall weight. \\ \end{tabular} \\ \hline Fuel cell, battery, and solar cells & \begin{tabular}{c} The inclusion of an additional \\ energy source in a hybrid power \\ supply system results in improved \\ endurance for the UAV. This extra \\ source provides clean and readily \\ available energy, which leads to a \\ decrease in energy costs and saves \\ on hydrogen usage. \\ \end{tabular} & \begin{tabular}{c} Large UAV wings are necessary for the \\ implementation of a hybrid power \\ supply system. However, this \\ configuration is not suitable for \\ rotary-wing UAVs. Additionally, an \\ energy storage device is required to \\ store and manage the energy generated \\ by the system. The hybrid system also \\ necessitates the use of an energy \\ management system (EMS) and \\ Maximum Power Point Tracking \\ (MPPT) to optimize the power flow and \\ ensure efficient operation. \\ \end{tabular} \\ \hline \hline Fuel cell, battery, and supercapacitor & \
\begin{tabular}{c} The hybrid system consisting of a \\ fuel cell, battery, and supercapacitor \\ offers several advantages. It \\ provides very-high-power density, \\ enabling efficient and rapid \\ charging. It also contributes to \\ reduced weight and minimized \\ fluctuations in the direct current \\ (DC) bus. The system exhibits a \\ very long lifetime, thanks to its \\ reduced internal resistance, and \\ experiences minimal heat loss. \\ These features make the hybrid \\ system highly desirable for various \\ applications, ensuring optimal \\ performance and reliability. \\ \end{tabular} &
\begin{tabular}{c} The integration of an energy \\ management system (EMS) is essential \\ in the hybrid system, which includes a \\ fuel cell, battery, and supercapacitor \\ The EMS plays a crucial role in \\ coordinating and regulating the power \\ flow between these components. It \\ ensures efficient utilization of the \\ energy sources, manages charging and \\ discharging processes, and maintains \\ the stability of the system. Additionally, \\ the voltage regulation of the \\ supercapacitor is necessary to ensure its \\ proper operation and prevent any \\ voltage-related issues. The EMS and \\ supercapacitor voltage regulation \\ contribute to the overall performance \\ and reliability of the hybrid system. \\ \end{tabular} \\ \hline \end{tabular}
\end{table} 
Table 7: _Cont._By comparing and analyzing various power supply architectures and energy management strategies, this research paper aims to contribute to the advancement of efficient and reliable UAV propulsion systems. The objective is to enable UAVs to operate optimally in different mission scenarios, enhance overall performance, extend mission durations, and improve the adaptability of the propulsion system to changing operating conditions. Therefore, some key points regarding the advantages and limitations of different power sources for UAV propulsion systems are highlighted. Combustion engines, although robust, are typically heavier and more commonly used in fixed-wing UAVs. On the other hand, fuel cells (FCs) and batteries, such as lithium polymer (Li-Po) batteries, offer longer flight times and greater maneuverability. However, they may struggle to supply peak current when required and can deplete their energy rapidly.