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This paper presents the world's first flight test results of a hydrogen fuel-cell/battery/supercapacitor triple hybrid power system for UAV propulsion. An introduction to the flight test vehicle is provided, followed by details of the fuel-cell, battery and supercapacitor and integration to form a cohesive triple hybrid power system in the UAV. Fli...
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... Yunasko supercapacitor consists of small pouches assembled together in a compact rectagular shape. A maximum voltage of 25 V was selected to provide a well matched system for the Specktronik fuel cell, with an overall ca- pacity of 7 F. Two assembled Yunasko superca- pacitor modules are shown in Figure 4, with the specifications of the modules given in Table 4. ...
Citations
... A known approach [2,3] to increase the SC energy density due to replacing one of the two electrodes with that from a battery technology cannot improve the situation significantly since in such a series connection of two different electrodes the low capacity electrode borrowed from SC technology limits the capacitance thus providing an approximately 2-fold increase in energy, namely, only up to 40-50 kJ/kg or 12-15 Wh/kg in common engineering units. Alternatively, a parallel combination of SC and battery (LIB or fuel cell or both) is a natural and effective solution to this issue, where the battery provides the required energy consumption, while SC covers peak loads [4,5]. However, the parallel combination of two current sources, each of which contains a number of SC and LIB single cells connected in series to achieve the desired voltage, leads to a corresponding increase in mass and volume caused by a separate packaging of each source, two monitoring and managing systems (BMS), and additional contacts. ...
As it turns out, the right combination of Li-ion and supercapacitor ingredients in both the positive and negative electrodes, as well as in the electrolyte, can significantly improve the characteristics of such a hybridized power supply as compared with “parent” systems. While Li-ion components provide large volumetric energy, the high surface area of nanoporous carbon borrowed from supercapacitor technology provides fast charge-discharge of the corresponding electric double layer and facilitates the intercalation-deintercalation processes in the Li-ion components. This full hybridization of the system can increase the energy density by 10 times that of a supercapacitor while maintaining the relatively high power density, long cycle life, and fast charging characteristics of supercapacitors. In addition, charge-discharge curves and low self-discharge currents become similar to those of Li-ion batteries. Such power supplies with a specific energy of 60+ Wh/kg, a full charge within 5–6 minutes and more than 30 K full charge-discharge cycles can be successfully used, for example, in urban transport or robotics in warehouses where the range is less critical than fast charging capability, long service life and safe operation. This article discusses the methods of full hybridization and the achieved characteristics of electrochemical systems “supercapacitor and Li-ion battery”. Special attention is paid to the “interaction” of the activated carbon surface with the channels in the bulk lithiated metal-oxide material of the electrodes to accelerate the charge-discharge processes.
... The researchers showed that the supercapacitor performed well -both in terms of load smoothing and dynamic response. Moreover, in some other studies, using the same UAV configuration (Gong et al. 2018) involved actual flight testing with a deployed UAV prototype, with resulting data demonstrating that the supercapacitor can provide optimum power and resolve power fluctuations during dynamic flights involving changing load conditions. Despite the DC bus voltage stabilization also being shown, there was a lack of studies that addressed EMS strategy. ...
... This 3-m aircraft includes a new hybrid gas/biodiesel-electric power train operating in internal combustion, hybrid, or electric mode. Gong et al. presented a flight test of a triple-hybrid propulsion system UAV consisting of a fuel cell, a battery, and a supercapacitor [30]. This triple hybrid propulsion system combines the performance benefits of each power source. ...
Drones have evolved rapidly over the decades, but the limited flight time inhibits multirotor drones from performing long-duration tasks. Batteries that power drones are considered an inadequate power source due to their low energy density. As gasoline is an energy-dense source, combining an electric propulsion system with gasoline engines should be considered. This paper proposes a novel hybrid multirotor drone design using two gasoline engines to provide the majority of the lift force and four electric motors to stabilize the drone. These propulsion systems have been characterized and optimized to exploit their respective advantages, which reduce the total energy consumption rate and increase flight time. Simulation and experimental results show that the hybrid gas–electric multirotor drone can achieve more than three times the flight time of the fully electric drone.
... The UAM market is expected to grow at an average annual rate of 30% or higher and will be introduced in 31 cities by 2030. UAM development is most active in the United States, and purely battery-powered vehicles were observed as taking up the largest proportion in classification by energy source [8,9]. ...
This paper presents an open innovation strategy by identifying the patent impact index and cooperation network through patent analysis for leading companies developing technology in the UAM field. Among companies developing UAM technology, patent analysis was conducted on the leading companies with active patent activities, technology classification was used to match companies by parts, and a technical capability index was utilized to identify the companies. When developing UAM technology in the future, this can help companies seek effective partners to improve competitiveness in technology development. To the best of our knowledge, the work done in this paper is unprecedented, as it suggests methods for patent analysis and verifies them by analyzing the UAM patents with the proposed method.
... The UAM market is expected to grow at an average annual rate of 30% or higher and will be introduced in 31 cities by 2030. UAM development is most active in the United States, and purely battery-powered vehicles were observed as taking up the largest proportion in classification by energy source [8,9]. ...
This paper presents an open innovation strategy by identifying the patent impact index and cooperation network through patent analysis for leading companies developing technology in the UAM field. Among companies developing UAM technology, patent analysis was conducted on the leading companies with active patent activities, technology classification was used to match companies by parts, and a technical capability index was utilized to identify the companies. When developing UAM technology in the future, this can help companies seek effective partners to improve competitiveness in technology development. To the best of our knowledge, the work done in this paper is unprecedented, as it suggests methods for patent analysis and verifies them by analyzing the UAM patents with the proposed method.
... The researchers showed that the supercapacitor performed well-both in terms of load smoothing and dynamic response. Moreover, in some other studies, using the same UAV configuration (Gong et al., 2018) involved actual flight testing with a deployed UAV prototype, with resulting data demonstrating that the supercapacitor can provide optimum power and resolve power fluctuations during dynamic flights involving changing load conditions. Despite the DC bus voltage stabilization also being shown, there was a lack of studies that addressed EMS strategy. ...
Due to technology breakthroughs, mobility services are witnessing exceptional levels of innovation. These technology advancements in autonomous unmanned aerial vehicles (UAVs or drones), as well as developing regulations, may soon pave the path for their widespread use in delivery systems. The optimally of these growing delivery systems has been considered an essential aspect due to the necessity of energy-saving, CO2 emission, and ultimately environmental benefits in recent years. To accomplish the optimality of these systems, drones often employ a hybrid power supply system architecture to boost endurance and performance. Fuel cells, batteries, solar cells, and supercapacitors are examples of power sources that may be combined in a hybrid power architecture. To allow the effective functioning of modern drones, not only an appropriate energy management system must be chosen, but also accurate and optimal modeling should be provided. This chapter proposes a comprehensive review on drone energy supply management and strategies systems to identify gaps and provide insights and recommendations for future research.
... Indeed, they absorb the DC bus voltage fluctuations and can extend battery lifetime [7]. Thus, they provide load smoothing and reduce the rate of change of current seen by the fuel cell during a dynamic flight [12]. ...
Electric propulsion unmanned aerial vehicles (UAVs) attract much attention in aviation industry, with electric vertical take-off and landing (eVTOL) aircraft tending to gain ground. The current development of hybrid eVTOL aircraft intended for urban air mobility is facing many technical challenges. Among these challenges rises the optimal sizing of its hybrid power system (HPS). The latter requires an energy management strategy (EMS). In this paper, the adopted management strategy is based on filtering techniques using frequency-separation. The EMS ensures the optimal distribution of the load power requirement between the different sources while considering their limits. In addition, the optimal sizing allows to strengthen the complementarity between sources and to indirectly reduce their mass. In this work, the studied HPS consists of a fuel cell associated with an energy storage system (ESS), composed of lithium polymer batteries (Li-Po) and supercapacitors. The onboard sources are connected in parallel on the power bus through three DC-DC converters. The results of this study are presented and discussed to highlight the relevance of the proposed approach.
... In light of this, embedding a supercapacitor as a supplementary power source in UAV's hybrid power architecture will boost power density and deliver a faster power response. An investigation of a hybrid UAV propulsion system involving fuel cell, battery, and supercapacitor was conducted by the authors of [24,25]. The results demonstrated the good performance of the supercapacitor in both delivering peak power and absorbing power fluctuations during dynamic flight with rapid changes in power load. ...
Interest in electric unmanned aerial vehicles (UAVs) has grown rapidly in recent years, and their applications have expanded and diversified considerably since they first appeared, for both commercial and private purposes. Thanks to their ability to perform challenging and hazardous tasks with high mobility, safety, and low cost. As academic researchers, we are concerned with commercial multi-rotor UAVs, which are revolutionizing many public services, including search and rescue operations, wireless coverage, delivery services, precision agriculture, wildlife surveys, and real-time surveillance. One of the UAVs main issues when it comes to mobility is the limited energy autonomy/endurance. Many types of power supplies can be implemented in UAVs, each with its specific strengths and shortfalls in terms of size, charging/discharging time, energy density and power density. This paper focuses on UAVs energy aspect, with a comprehensive review of the main power sources available for multi-rotors UAVs, and energy management systems to uncover gaps and provide further insights and guidelines for future research.
... The latter will be discussed in the proceeding section. Today's hydrogen fuel-cell-based hybrid power systems are considered a technology to advance the range and endurance of electrically-powered UAVs [1], [29]. Fuel cells are electrochemical devices that constantly generate electrical energy and remain functional if fuel and oxidizers are delivered. ...
... 40, No. 6, November 2021. power sources, zero CO2 emissions, reduced noise, less vibration, and low thermal signatures [12], [29]. In addition, in systems driven by reciprocating and jet engines, fuel only adds about 18-25% of energy to propulsion, whereas in fuel cell-powered propulsion, this effectiveness is in the region of 44%. ...
... The four different types of GTEs [13] The shortcomings of hydrogen fuel-cell-based hybrid power systems include cost, the sensitivity of the electrode catalyst to poisoning, and the safety concerns on storage of hydrogen among others [4], [7], [15], [29]. The most common type of fuel cell designed to power UAVs is the proton exchange membrane fuel cell (PEM) [1]. ...
This review paper discussed the different types of propulsion technologies for unmanned aerial vehicles (UAVs). In it, several UAV propulsion systems were investigated, with particular emphasis on internal combustion engine (ICEs)-powered propulsion systems and electrically powered propulsion systems. The characteristics and working principles of these propulsion systems and challenges were discussed in this paper. Also, the methods in which future generations of UAVs can perform better have been discussed particularly with regards to endurance characteristics, power-to-weight ratios, and environmental wise. Similarly, the relevance of future UAV propulsion systems, which is a hybrid of the two major propulsion systems (ICEs and electric systems), giving a yield for high endurance, long-range, and durability, is discussed.
... The latter is especially important for multirotor drones because it has a large impact on the system mass and the dynamic response. One promising approach to improve hybrid systems is to use a supercapacitor, as demonstrated by Gong et al. (2018). ...
Increased flight time of multirotor drones is a key enabler for further adoption and industrial use of drones. A model for analyzing the performance of a fuel cell hybrid system for a multirotor drone is presented and applied for a case with an X8 multirotor drone with a maximum take-off mass of 25 kg. Endurance is the main performance parameter, and the model can be used to quantify the relative performance between different power sources. The model aims to determine if a specific hybrid fuel cell system is a viable option for a given multirotor drone and if it will provide better endurance than when powered by batteries. The model can also be used in system optimization and sensitivity analysis. In a case study, a fuel cell hybrid system with a 7.2 L cylinder with hydrogen at 300 bar is found to increase the flight time by 43 minutes (+76%) from the currently used LiPo-batteries. A plot identifies the energy system mass threshold for when the fuel cell hybrid system gives better endurance than batteries to be 7.3 kg. Based on current technology status, the cost of a fuel cell hybrid system is about 12 times that of LiPo-batteries.
