All-electric Aircraft Research Articles

An Analysis of a Complete Aircraft Electrical Power System Simulation Based on a Constant Speed Constant Frequency Configuration

Recent developments in aircraft electrical technology, such as the design and production of more electric aircraft (MEA) and major steps in the development of all-electric aircraft (AEA), have had a significant impact on aircraft’ electrical power systems (EPSs). However, the EPSs of the latest aircraft produced by the main players in the market, Airbus with the Neo series and Boeing with the NG and MAX series are still completely traditional and based on the constant speed constant frequency (CSCF) configuration. For alternating current ones, the EPS is composed of the following: prime movers, namely the aircraft turbofan engine (TE); the electrical power source, i.e., the integrated drive generator (IDG); the command and control system, the generator control unit (GCU); the transmission and the system distribution system; the protection system, i.e., the CBs (circuit breakers); and the electrical loads. This paper presents the analysis of this system using the Simscape package from Simulink v 8.7, a MATLAB v 9.0 program, which is actually the development of some systems designed in two previous personal papers. For the first time in the literature, a complete MATLAB modelled EPS system was presented, i.e., the aircraft turbofan engine model, driven by the constant speed drive system (CSD) (model presented in the first reference as a standalone type and with different parameters), linked to the synchronous generator (SG) (model presented in second reference for lower power and rotational speed) in the so-called integrated drive generator (IDG) and electrical loads.

Weight-Constrained Reliability Allocation for All-Electric Aircraft Powertrains

Weight-Constrained Reliability Allocation for All-Electric Aircraft Powertrains

One-Step Fabrication of Composite Hydrophobic Electrically Heated Graphene Surface

Ice accumulation poses considerable challenges in transportation, notably in the domain of general aviation. The present study combines the strengths and limitations of conventional aircraft deicing techniques with the emerging trend toward all-electric aircraft. This study aims to utilize laser-induced graphene (LIG) technology to create a multifunctional surface, seamlessly integrating hydrophobic properties with efficient electrical heating to mitigate surface icing effectively. We investigated the utilization of a 10.6 μm CO2 laser for direct writing on polyimide (PI), a widely used insulating encapsulation material. From the thermomechanical perspective, our initial analysis using COMSOL Multiphysics software (V5.6) revealed that when the laser power P exceeds 5 W, the PI substrate experiences ablative damage. The experimental results show that when P ≤ 5 W, an increase in power has a positive impact on the quality, surface porosity, roughness reduction, line-spacing reduction, and water contact-angle enhancement of the graphene. Conversely, when P > 5 W, higher power negatively affects both the substrate and the graphene structure by inducing excessive ablation. However, it influences the graphene line height positively and is consistent with overall experimental–simulation congruence. Furthermore, the incorporation of high-quality graphene resulted in a surface that exhibited higher contact angles (CA > 120°), lower energy consumption, and higher heating efficiency compared to the use of traditional electrically heated materials for anti-icing applications. The potential applications of this one-step fabrication method extend across various industries, particularly aviation, marine engineering, and other ice-prone domains. Moreover, the method has extensive prospects for addressing pivotal challenges associated with ice formation and serves as an innovative and efficient anti-icing technology.

Thin-Film Embedded Sensors for Battery Health Monitoring

Hybrid or all-electric aircraft are being developed as the next generation of aircraft to both allow new forms of aviation and decrease environmental impact. Since these types of aircraft are based on high-capacity battery technology, safe operation of these batteries becomes increasingly important. In particular, the potential for battery failure due to uncontrolled chemical reactions resulting in thermal runaway, catastrophic failure, and battery fires must be addressed in order for such battery technology to have the level of safety needed for standard aviation implementation. Efforts to ensure battery safety often involve engineering solutions that seek to contain rather than prevent such events by early detection. Such approaches increase the system weight and decrease the power per unit mass provided by the battery system. Existing methods for measuring battery parameters to determine the battery state-of-health are limited. These methods include electrical measurements of the cell current and/or voltage output as well as temperature measurements taken externally on the cell surface. Such external temperature measurements are limited in their ability to provide early warning of impending battery failure. In response, an effort to develop sensors operating internal to battery for health monitoring has been ongoing in the NASA Sensor-based Prognostics to Avoid Runaway Reactions & Catastrophic Ignition (SPARRCI) project [1]. The basic approach associated with this sensor work is the deposition of thin film sensors on the battery separator located between the anode and cathode of the battery. These thin film sensors are then monitored to determine changes in battery parameters and health. Microfabrication techniques are employed to minimize the overall impact of the sensors on battery operation through the implementation of sensors with minimal size, weight, and power consumption. The thickness of the films, which are fabricated through physical vapor deposition (sputtering), are on the order of thousands of angstroms and can have minimal surface area. Thin film sensors for system health management have been implemented for a many decades on complex components for aerospace applications [2,3]. However, the application of thin films of this type on a battery separator for internal battery monitoring applications has not previously been demonstrated to our knowledge. This paper describes the development of sensors for the internal battery monitoring through the use of thin film sensor technology. Thin metal films were successfully deposited on a battery separator polymer material with good adherence and electrical continuity. Multiple types of sensors have been deposited, as well as lead connections from the sensor to the edge of the separator material. The ability of these thin film sensors immersed in electrolyte to perform multiple types of battery parameter measurements has been demonstrated. For example, a multiparameter sensor system measured multiple properties simultaneously inside of a pouch cell over a wide temperature range. Further, real time measurement of interior temperature changes in a battery pouch cell with an integrated interior temperature sensor was demonstrated. These changes include detecting a fault in the battery (shorting) in situ with rapid response time (less than a minute) corresponding to a more limited response by a temperature sensor mounted externally. Other aspects of monitoring battery health were also explored, such as real-time measurement of simulated dendrite growth/metal deposition by sensor on separator material demonstrated. Future efforts will include improvements in the durability of the sensor structure to allow introduction of the approach into standard battery fabrication techniques. Overall, this work is a step forward in providing a method to prevent catastrophic battery failures and provide a foundation for safer, lighter, and higher energy batteries for the electric aircraft industry.[1] B. DeMattia, Daniel Perey, John Lawson, and Gary Hunter, “Advanced Battery Health Approaches for Electric Aircraft”, Energy & Mobility Technology, Systems, and Value Chain Conference & Expo, Cleveland, OH, Sept. 23, 2023.[2] John D. Wrbanek, and Gustave C. Fralick, “Thin Film Physical Sensor Instrumentation Research and Development at NASA Glenn Research Center”, 52nd International Instrumentation Symposium Cleveland, OH, May 2006, NASA TM-2006-214395[3] Lawrence G. Matus (2015) “Instrumentation for Aerospace Applications: Electronic-Based Technologies”, Journal of Aerospace Engineering 26 (2) https://doi.org/10.1061/(ASCE)AS.1943-5525.0000302

Flow-Based Assessment of the Impact of an All-Electric Aircraft on European Air Traffic

The consequences of new airspace entrants, such as novel aircraft concepts with innovative propulsion systems, on air traffic management operations need to be carefully identified. This paper aims to assess the impact of future aircraft with different performance envelopes on the European air traffic network from a flow-based perspective. The underlying approach assumes that all certification-related questions concerning airworthiness have been resolved and do not take into account any economic factors related to airline operations. For example, for an innovative propulsion system, a short range all-electric aircraft is considered in this study. Aircraft trajectory calculations are based on the dataset of base of aircraft data (BADA), which are developed and maintained by EUROCONTROL. The new design concept is integrated into BADA as well, resulting in a new set of coefficients for the all-electric aircraft. In addition to the adjusted parameters which affect airborne performances, ground-related aspects are also taken into account. This includes assumptions on operational procedures, charging capacities and adaptions in infrastructure. Investigations are carried out at the trajectory level as well as at the airport and the entire network.

Aircraft electric power plants

The paper presents a review of electrification of the existing propulsion systems and creating new hybrid propulsion systems based on the concept of more electric aircraft and all-electric aircraft in Russia and abroad. New promising directions of electrification of the existing aircraft propulsion systems and creating new hybrid aircraft propulsion systems are specified on the basis of the review.

Optimized Fabrication Process and PD Characteristics of MVDC Multilayer Insulation Cable Systems for Next Generation Wide-Body All-Electric Aircraft

For wide-body all-electric aircraft (AEA), a high-power-delivery, low-system-mass electric power system (EPS) necessitates advanced cable technologies. Increasing voltage levels enhances power density yet poses challenges in aircraft cable design, including managing arc-related risks, partial discharges (PDs), and thermal management. Developing multilayer multifunctional electrical insulation (MMEI) systems for aircraft applications is a feasible option to tackle these challenges and reduce the size and mass of cable systems. This approach involves selecting layers of different materials to address specific challenges. Our prior research concentrated on the modeling and simulation-based design of MMEI systems for MVDC power cables. Experimental tests are essential for determining the behavior of PDs under varying pressure conditions. Also, the dielectric strength and time to failure of the designs need to be assessed. In this work, the fabrication process of a down-selected MMEI flat configuration is discussed and analyzed. This paper analyzes the fabrication process of power cables employing MMEI configurations and evaluates the PD characteristics of down-selected ARC-SC-T-MMEI cable samples. This study presents a detailed analysis of the characteristics of PD under atmospheric and low-pressure conditions, which will provide essential insights into the design of MVDC cables for future AEA applications.

AC transport loss analysis of HTS stack busbars for all-electric aircraft with harmonics and DC offset considerations

This paper presents a study of the current carrying capacity and AC loss of high-temperature superconducting (HTS) stacks to be used in busbar applications for all-electric aircraft. A 2D model was developed using COMSOL Multiphysics with a T-A formulation for detailed analysis. The study began by applying a stable 20 kA DC offset current to the HTS stacks to simulate practical operating conditions. Firstly, the behaviour of the critical current was studied under self-field conditions for stacks with different numbers of HTS tapes and spacing. Secondly, AC ripple currents were introduced with DC offsets, and the effects of 3rd and 5th harmonic distortions (HD) were studied. The results show that configurations with 40 tapes and gaps of more than 2 mm are considered suitable for safe current transport under DC conditions. On the other hand, increasing the tape spacing leads to an increase in the safe transport current ripple due to the reduced magnetic field interaction within the stack. In addition, the transport loss decreases as the air gap increases due to the reduction in the self-field, whereas it increases as the number of strips increases. The influence of the 3rd HD on the transport loss is minimal at a ripple current of 1% and slightly noticeable at 2%. However, it becomes more obvious as the ripple current approaches the critical value. Remarkably, even cases with equivalent total HD show significantly higher transport losses when characterised by higher 5th HD than their counterparts with 3rd HD. This comprehensive analysis provides valuable information on the performance characteristics of HTS stacks in all-electric aircraft busbar applications and offers important insights for the development and optimisation of these systems in practical aerospace applications.

Dynamic modeling of a cantilever reed valve considering squeeze flow with experimental validation

Piezoelectric hydraulic pumps play a pivotal role in more electric aircraft and all-electric aircraft utilizing power-by-wire technology, owing to their high power density and reliability. The cantilever reed valve (CRV) serves as a crucial component within these pumps, and its dynamic behavior within the fluid directly impacts the pumps' output power. A precise mathematical model of the CRV is essential for understanding its motion mechanisms. However, existing models for the CRV inadequately capture its dynamics and fail to explain the observed motion phenomena. Further exploration into dynamic modeling of the CRV is warranted. This paper employs finite element analysis to investigate CRV's dynamics, revealing the significant impact of squeeze flow on CRV's dynamics and identifying the cause of slow closure. Based on this, a novel lumped parameter model incorporating squeeze force is proposed to accurately depict CRV's dynamics, particularly focusing on the phenomenon of slow closure. To validate the proposed model's accuracy, an experimental system capable of independently driving the CRV is constructed to eliminate interference resulting from integrating the CRV into the pumps. The results show that the dynamic response during closure, as predicted by the proposed model, is in good agreement with the outcomes from finite element analysis. Notably, the proposed model exhibits an 11.11% higher prediction accuracy for experimental closing times compared to the traditional model that neglects squeeze forces. This study offers guidance for optimizing CRV's dynamics and improving the performance of piezoelectric hydraulic pumps in future applications.

A Range Prediction Method for All-Electric Aircraft by Capacity Discretization-Based Iterative Convex Programming

A Range Prediction Method for All-Electric Aircraft by Capacity Discretization-Based Iterative Convex Programming

Negative Medium-Voltage Direct Current Discharges in Air under Simulated Sub-Atmospheric Pressures for All-Electric Aircraft

The increase in the global temperature due to greenhouse gas emissions is a major concern to the world. To achieve the goal of zero emissions by 2050 in the USA the practical realization of all-electric vehicles, particularly all-electric aircraft (AEA), is important. For the design of electrical power systems (EPSs) in all-electric aircraft, a bipolar medium-voltage direct current (MVDC) system of ±5 kV is being investigated. However, several challenges manifest when using such voltages in a low-pressure environment. One of the main challenges is the partial discharge (PD) behavior of the insulation. It is important to study the PD behavior of the insulation by simulating the aviation environment in the lab. This work aimed to study the partial discharge behavior of air under a negative DC voltage in a needle-to-plane electrode geometry by simulating the aviation pressures in the lab. The partial discharge inception voltage (PDIV) and the breakdown voltage (BDV) show an obvious pressure-dependent variation. Regression analysis was performed to better understand the relationship between the PDIV and pressures. Plots were drawn for the average discharge current at each voltage step until breakdown. This paper’s findings can provide valuable insight into the design of EPS for an AEA. To the best of our knowledge, such a study has not been carried out to date.

Investigation of friction and vibration performance of lithium complex grease containing candle soot on aviation electrical machine

The prolonged operation of the motor in the all-electric aircraft can cause the fragmentation and shortening of grease thickener fibers, ultimately resulting in the lubricating grease becoming ineffective. In order to avoid grease failure causing motor winding burnout, this paper uses a four-ball friction testing machine to test the tribological properties of six composite greases containing candle soot with different concentrations, and analyzes the changes in friction coefficient and wear diameter. In addition, by building a test platform for motor vibration and noise, this paper studies the influence of lithium complex grease on vibration and noise characteristics of aviation electrical machine at different propeller speeds. The results show that the addition of 0.04 wt% candle soot lithium grease has the best tribological properties and vibration inhibition properties, because the candle soot in the oil film changes the sliding friction into rolling friction in the contact area of some friction pair. The temperature rise test of aviation electrical machine shows that the lithium complex grease plays an active role in the heat dissipation performance of the high-speed rotating motor.

Integrated Power and Thermal Management Systems for Civil Aircraft: Review, Challenges, and Future Opportunities

Projects related to green aviation designed to achieve fuel savings and emission reductions are increasingly being established in response to growing concerns over climate change. Within the aviation industry, there is a growing trend towards the electrification of aircraft, with more-electric aircraft (MEA) and all-electric aircraft (AEA) being proposed. However, increasing electrification causes challenges with conventional thermal management system (TMS) and power management system (PMS) designs in aircraft. As a result, the integrated power and thermal management system (IPTMS) has been developed for energy-optimised aircraft projects. This review paper aims to review recent IPTMS progress and explore potential design solutions for civil aircraft. Firstly, the paper reviews the IPTMS in electrified propulsion aircraft (EPA), presenting the architectures and challenges of the propulsion systems, the TMS cooling strategies, and the power management optimisation. Then, several research topics in IPTMS are reviewed in detail: architecture design, power management optimisation, modelling, and analysis method development. Through the review of state-of-the-art IPTMS research, the challenges and future opportunities and requirements of IPTMS design are discussed. Based on the discussions, two potential solutions for IPTMS to address the challenges of civil EPA are proposed, including the combination of architecture design and power management optimisation and the combination of modelling and analysis methods.

Breaking economies of scale: commercial and operational viability of all-electric aircraft as regional hub feeder

All-electric aircraft with a capacity of 40-50 seats are expected to come into operations before the end of this decade. This paper investigates the operational and commercial challenges in employing all-electric aircraft as feeder for a hub. Based on announcements for electric aircraft projects a probable set of specifications for a future all-electric aircraft with 44 seats will be proposed. Through a bottom-up calculation of the direct cost of operating a feeder flight it will be determined that the model all-electric aircraft has direct cost 10% below an ATR42-500 with the same seating capacity. Assuming more favorable conditions concerning electricity supply and fee structure a further 23% could be saved for the all-electric aircraft. This would undercut the unit cost of an Embraer E190 with 108 seats by 10% breaking the current economies of scale. Consequently, the profit per flight increases, since these seats can be sold at higher yields, addressing the customer segment with the highest willingness-to-pay. This positions an all-electric aircraft as a very attractive option for hub feeding by offering lower seat cost than jets with more than double the capacity. This commercial advantage is gained through the high efficiency of electric engines compared to internal combustion engines overcompensating the disadvantage of high battery weight.

Benefits and Challenges of Electric Propulsion for Commuter Aircraft

This paper presents the Library for Unified Conceptual Aircraft Synthesis (LUCAS) sizing and optimization framework, which is largely based on Stanford’s Stanford University Aerospace Vehicle Environment (SUAVE). LUCAS is applied to a commuter mission carrying 19 passengers. Results show that energy usage benefits depend on mission range and electrical component technology and that reserve requirements play a significant role in the feasibility of electrified aircraft. It is found that storing more energy in batteries rather than fuel reduces the mission energy requirement at the expense of aircraft weight growth. All-electric aircraft could provide onboard energy savings of upward of 30% for a 180 km mission, but this would only become feasible if battery specific energy reached the high value of 900 W⋅h/kg. Range could be increased to 550 km if part of the reserve mission requirements is relaxed. Under more realistic technology assumptions, a hybrid design storing energy in fuel and batteries could fly commuter missions with energy savings of 6%. A beneficial use case of hybrid configurations is a mode of operation where the aircraft uses only batteries during the main mission and fuel to store all the reserve energy. If reserves are not required for a particular flight, energy savings are still maximized, while the availability of fuel ensures certification requirements are met with fewer penalties.

General issues of ensuring electromagnetic compatibility of aircraft on-board equipment

The article examines the effect of electromagnetic interference on the electrical components of the aircraft from the point of view of external and internal electromagnetic environments. The external electromagnetic environment consists of high-intensity radiated fields and lightning strikes. Internal threats can be divided into four types: intersystem, intra-system, induced radiated fields of high intensity and internal transients during a lightning strike. On the basis of the considered impact, the article defines the directions of development in the field of providing electromagnetic compatibility for an all-electric aircraft.

Design of a Novel Halbach Superconducting Geared Machine for an All-Electric Aircraft

Design of a Novel Halbach Superconducting Geared Machine for an All-Electric Aircraft

Charging Demand Prediction: Small All-Electric Aircraft and Electric Vertical Takeoff and Landing Aircraft

Charging Demand Prediction: Small All-Electric Aircraft and Electric Vertical Takeoff and Landing Aircraft

Materials Challenges in the Development of All-Electric Aircraft

The global climate crisis has worsened as greenhouse gas emissions from production and transport activities have increased significantly. The idea of an all-electric airplane has been put out in reaction to the aviation industry’s fast expansion’s negative environmental effects. The traditional aviation model has brought huge economic benefits while leading to an increase in greenhouse gas emissions. This paper delves into the urgent need for aviation to reduce greenhouse gas emissions in the face of the global climate crisis and highlights the potential of electric aircraft as a key solution. The paper highlights the role that electric aircraft plays in cutting emissions and advancing sustainable development. It also outlines the obstacles that need to be overcome and future directions for advancement in the domains of integrated design, electric motor technology, and battery technology. Recent material innovations are also in focus, particularly the promise of high-temperature superconductors in electrical motor applications. Future research directions will focus on nanomaterials improvement, green production, and the development of high-performance environmentally friendly materials.

New-Energy Electric Aircraft: A Review of the Developments and Challenges of Core Technologies

In light of the escalating global energy crisis and exacerbating environmental dilemmas, nations worldwide are amplifying their investments and research endeavors in advanced aircraft energy systems. The collective objective is the realization of aircraft that epitomize low-emission, low-noise, and minimal pollution, ensuring enhanced safety and comfort while championing energy efficiency. This paper provides a comprehensive exploration of the pivotal technology underpinning electric aircraft, offering a detailed exposition of the current developmental landscape and the inherent challenges encountered. The discussion delves into the transition from multi-electric and all-electric aircraft to entirely electric aircraft, underscoring the technological advancements and innovations propelling this shift. The paper meticulously examines the multifaceted aspects of electric aircraft technology, highlighting the significant strides made and the obstacles that persist. In addition to presenting a coherent overview of the existing state of electric aircraft technology, the paper ventures to propose potential, viable solutions to the challenges identified. This exploration contributes to the burgeoning body of knowledge, aiding the ongoing efforts to enhance the sustainability, efficiency, and efficacy of aircraft energy systems, ultimately contributing to global environmental conservation and energy sustainability.