Modeling and simulation enabled UAV electrical power system design

With the diversity of mission capability and the associated requirement for more advanced technologies, designing modern unmanned aerial vehicle (UAV) systems is an especially challenging task. In particular, the increasing reliance on the electrical power system for delivering key aircraft functions, both electrical and mechanical, requires that a systems-approach be employed in their development. A key factor in this process is the use of modeling and simulation to inform upon critical design choices made. However, effective systems-level simulation of complex UAV power systems presents many challenges, which must be addressed to maximize the value of such methods. This paper presents the initial stages of a power system design process for a medium altitude long endurance (MALE) UAV focusing particularly on the development of three full candidate architecture models and associated technologies. The unique challenges faced in developing such a suite of models and their ultimate role in the design process is explored, with case studies presented to reinforce key points. The role of the developed models in supporting the design process is then discussed

Frontiers in nano-architectured carbon–metal oxide electrodes for supercapacitance energy storage

Supercapacitor (SC) is an energy storage technology that bridges the gap between conventional capacitors and rechargeable batteries. Emerging nano-architectured carbon–metal oxide composites are promising for electrode designs for supercapacitors due to their unique strategy utilizing electrochemical double-layer capacitance (EDLC) and pseudo-capacitance together in single cell to optimize the energy storage ability and electrochemical stability. In recent years, technologies of integrating different metal oxide into single-walled/multi-walled carbon nanotubes (CNTs), graphene/reduced graphene oxide (rGO) and carbon nanofiber (CNF) and/or carbon fiber paper (CFP) have been reported with the focus of the nano-architecture electrodes. This paper provides a review of the frontiers with respect to incorporation of metal oxides into the carbon nanomaterials for capacitive energy storage improvements. Several key performance parameters in terms of specific capacitance, energy density, power density and cyclic stability along with the challenges and design trends are discussed and summarized

A refined loss evaluation of a three-switch double input DC-DC converter for hybrid vehicle applications

open3noIn this paper, an accurate efficiency evaluation of an innovative three-switch double input DC-DC converter for hybrid vehicle applications was carried out. The converter was used to interface two storages, (e.g., supercapacitor and battery) to the DC link. A refined model was created in MATLAB/Simulink Plecs environment and it was used to compare the traditional four-switch converter (i.e., two DC-DC converters in parallel connection) with the innovative three-switch converter. Loss and efficiency contour maps were obtained for both converters and a comparison between them was performed. A prototype of the three-switch converter was realized and used to validate the simulation thermal model by comparing both efficiency and current waveforms obtained with simulations and experimental tests.openMarchesoni M.; Passalacqua M.; Vaccaro L.Marchesoni, M.; Passalacqua, M.; Vaccaro, L

A Hybrid Energy Storage System for a Coaxial Power-Split Hybrid Powertrain

A hybrid energy storage system (HESS) consisting of batteries and supercapacitors can be used to reduce battery stress and recover braking energy efficiently. In this paper, the performance of a novel coaxial power-split hybrid transit bus with an HESS is studied. The coaxial power-split hybrid powertrain consists of a diesel engine, a generator, a clutch, and a motor, whose axles are arranged in a line. A mathematical model of the coaxial power-split hybrid powertrain with an HESS is established and the parameters are configured using experimental data. Subsequently, to estimate the system performance, a program is designed based on Matlab and Advisor. A rule-based control strategy is designed and finely tuned for the coaxial power-split hybrid powertrain. Then, using the Chinese Transit Bus City Driving Cycle (CTBCDC), the system characteristics and energy efficiencies of the designed coaxial power-split hybrid powertrain with an HESS are analysed. The results indicate that the proposed coaxial power-split hybrid powertrain with an HESS can fulfil the drivability requirement of transit bus and enhance the energy efficiency significantly compared with a conventional powertrain bus as well as reduce the battery stress simultaneously. Using an HESS is a good solution for the coaxial power-split hybrid transit bus

Survey of Energy Harvesting Technologies for Wireless Sensor Networks

Energy harvesting (EH) technologies could lead to self-sustaining wireless sensor networks (WSNs) which are set to be a key technology in Industry 4.0. There are numerous methods for small-scale EH but these methods differ greatly in their environmental applicability, energy conversion characteristics, and physical form which makes choosing a suitable EH method for a particular WSN application challenging due to the specific application-dependency. Furthermore, the choice of EH technology is intrinsically linked to non-trivial decisions on energy storage technologies and combinatorial architectures for a given WSN application. In this paper we survey the current state of EH technology for small-scale WSNs in terms of EH methods, energy storage technologies, and EH system architectures for combining methods and storage including multi-source and multi-storage architectures, as well as highlighting a number of other optimisation considerations. This work is intended to provide an introduction to EH technologies in terms of their general working principle, application potential, and other implementation considerations with the aim of accelerating the development of sustainable WSN applications in industry

Energy Storage Systems for Traction and Renewable Energy Applications

Energy storage systems are the set of technologies used to store various forms of energy, and by necessity, can be discharged. Energy storage technologies have a wide range of characteristics and specifications. Like any other technology, each type of energy storage has its pros and cons. Depending on the application, it is crucial to perform a tradeoff study between the various energy storage options to choose the optimal solution based on the key performance objectives and various aspects of those technologies. The purpose of this thesis is to present a thorough literature review of the various energy storage options highlighting the key tradeoffs involved. This thesis focuses on evaluating energy storage options for traction and renewable energy applicationsHybrid Electric Vehicles (HEVs) is one key application space driving breakthroughs in energy storage technologies. The focus though has been typically on using one type of energy storage systems. This thesis investigates the impact of combining several types of batteries with ultracapacitor. A case study of integrating two energy storage systems in a series-parallel hybrid electric vehicle is simulated by using MATLAB-SIMULINK software.The other key application space is renewable energy especially wind and solar. Due to the intermittent nature of renewable energy sources, energy storage is a must to achieve the required power quality. Therefore, this thesis aims to investigate different cases of combining different types of energy storage with wind and solar. Hybrid Optimization Model for Electric Renewables (HOMER) software is utilized to study the economic and sizing aspects in each case

Balancing Supercapacitor Voltages in Modular Bidirectional DC–DC Converter Circuits

At present, passive balancing methods dominate energy storage applications, however, they suffer from a long balancing duration. In this article, we took advantage of a modular architecture, where several modular power converters replace a central dc–dc converter for fast charging and balancing of a supercapacitor stack. A strategy has been proposed to control how power is shared among the converters during the charging period in order to balance the supercapacitors. However, some converters enter control saturation due to voltage differences between supercapacitors caused by their nonuniform conditions and characteristics. The originality of this article lies in taking into account the saturation by modifying an energy-based strategy to correct the power shares and make balancing the supercapacitors possible. Simulation and experimental case studies were used to demonstrate the strategy\u27s performance and limitations