Power Distribution and Propulsion System for an All-Electric Short-Range Commuter Aircraft—A Case Study

To participate in the transition towards a sustainable use of energy, the aircraft sector needs to be transformed with respect to the energy carrier and propulsion methods. For smaller aircraft, a battery-electric approach is promising. While this will require extensive research and design together with the application of advanced components which are partly not available to this date, general design rules and key parameters and critical components can already be deduced. This publication presents the example design of the full propulsion system for a small commuter aircraft. This serves as a case study to highlight the influence of components and parameters on the overall efficiency and weight of the system. By that, future research can be directed towards the areas of high impact on the realization of all-electric aircraft. A optimization of several motor variants, inverter topologies and power supply grid parameters is performed. The weight of the fully electric propulsion system is dominated by the battery. Therefore, all subsequent components need to be designed towards a high efficiency in opposition to high power density

Discussion on Electric Power Supply Systems for All Electric Aircraft

The electric power supply system is one of the most important research areas within sustainable and energy-efcient aviation for more- and especially all electric aircraft. This paper discusses the history in electrication, current trends with a broad overview of research activities, state of the art of electrication and an initial proposal for a short-range aircraft. It gives an overviewof the mission prole, electrical sources, approaches for the electrical distribution system and the required electrical loads. Current research aspects and questions are discussed, including voltage levels, semiconductor technology, topologies and reliability. Because of the importance for safety possible circuit breakers for the proposed concept are also presented and compared, leading to a initial proposal. Additionally, a very broad review of literature and a state of the art discussion of the wiring harness is given, showing that this topic comes with a high number of aspects and requirements. Finally, the conclusion sums up the most important results and gives an outlook on important future research topics

Power Semiconductors for An Energy-Wise Society

This IEC White Paper establishes the critical role that power semiconductors play in transitioning to an energy wise society. It takes an in-depth look at expected trends and opportunities, as well as the challenges surrounding the power semiconductors industry. Among the significant challenges mentioned is the need for change in industry practices when transitioning from linear to circular economies and the shortage of skilled personnel required for power semiconductor development. The white paper also stresses the need for strategic actions at the policy-making level to address these concerns and calls for stronger government commitment, policies and funding to advance power semiconductor technologies and integration. It further highlights the pivotal role of standards in removing technical risks, increasing product quality and enabling faster market acceptance. Besides noting benefits of existing standards in accelerating market growth, the paper also identifies the current standardization gaps. The white paper emphasizes the importance of ensuring a robust supply chain for power semiconductors to prevent supply-chain disruptions like those seen during the COVID-19 pandemic, which can have widespread economic impacts.The white paper highlights the importance of inspiring young professionals to take an interest in power semiconductors and power electronics, highlighting the potential to make a positive impact on the world through these technologies.The white paper concludes with recommendations for policymakers, regulators, industry and other IEC stakeholders for collaborative structures and accelerating the development and adoption of standards

Hairpin windings for high reliability and high power density electrical machines

In the last years the increasing demand of higher torque and power densities has led to the adoption of hairpin windings (HWs) in electrical machines, mainly in those intended for automotive applications. However, this winding topology is quite sensitive to AC losses, hence one of their main challenges is represented by their reduction. This work deals with different design aspects related to the enhancements of some performance figures of rotating electrical machines for traction applications, above all power density and reliability, mainly through the adoption of HWs.In the last years the increasing demand of higher torque and power densities has led to the adoption of hairpin windings (HWs) in electrical machines, mainly in those intended for automotive applications. However, this winding topology is quite sensitive to AC losses, hence one of their main challenges is represented by their reduction. This work deals with different design aspects related to the enhancements of some performance figures of rotating electrical machines for traction applications, above all power density and reliability, mainly through the adoption of HWs

Partial discharge inception voltage in turn-to-turn insulation systems: modelling and uncertainties

In the late 19th century, the extraordinary inventors and pioneers Nikola Tesla, Thomas Edison, and George Westinghouse dreamed of transforming the world. After more than a hundred years since then, electricity has not stopped growing and is set to become the largest industrial system created by humanity. The democratization of hybrid and electric cars, and even more the future electrification of the aeronautical industry are signs of its unstoppable evolution. As a system in constant improvement and evolution, it has not been without challenges to overcome without compromising its reliability. One of the phenomena that continues to be a threat and reduces the reliability of machines are partial discharges. These events affect the insulation system and can cause a material failure that can translate into equipment damage, power supply interruption and even incendiary and explosive events. One of the cornerstones that this electrical system relies on is alternating current motors. Spurred on by progress in semiconductors and the discovery of the microprocessor, aging of DC motors have taken over. Since then, the electronic control of these motors has become essential, to the point that for small power rated machines, a single set is sold: “copper, iron and silicon”. Unexpectedly, this improved speed control caused a significant reduction in the reliability of the motors, causing unforeseen failures in the insulation systems. Since the turn-to-turn insulation is the Achilles heel for most of these motors, this will be the core subject in this dissertation. This problem has been an ordeal in the way of designers, due to its stochastic nature and the uncertainties associated with the different models proposed in the literature. With the development of this thesis, it is intended to model the phenomenon of partial discharges, combining finite element calculations with the results obtained in laboratory tests, to predict the appearance of partial discharges. Likewise, the impact of the different sources of uncertainty on the models will be analyzed. These uncertainties constitute a powerful tool for electrical designers, since they mark the strategy to follow in their design, according to the boundary conditions of the system.A finales del siglo XIX, los extraordinarios inventores y pioneros Nikola Tesla, Thomas Edison y George Westinghouse soñaron con transformar el mundo. Tras más de cien años desde entonces, la electricidad no ha dejado de crecer y se postula a convertirse en el mayor sistema industrial creado por la humanidad. La democratización de los coches híbridos y eléctricos, y aún más la futura electrificación de la industria aeronáutica son muestras de su imparable evolución. Como sistema en constante mejora y evolución, no ha estado exento de desafíos que superar sin comprometer su fiabilidad del mismo. Uno de los fenómenos que continúa siendo una amenaza y reduce la fiabilidad de las máquinas son las descargas parciales. Estos eventos afectan al sistema de aislamiento, pudiendo ocasionar un fallo del material que se puede traducir en daños de los equipos, interrupción del suministro eléctrico e incluso eventos incendiarios y explosivos. Una de las piedras angulares que las que se apoya este sistema eléctrico son los motores de corriente alterna. Espoleados por el progreso en los semiconductores y el descubrimiento del microprocesador, se han impuesto a los vetustos motores de corriente continua. Desde entonces, el control de electrónico de estos motores se han hecho imprescindible, hasta el punto de que para pequeñas potencias se vende un solo conjunto: “cobre, hierro y silicio”. De manera inesperada, este control mejorado de la velocidad causó una importante reducción de la fiabilidad de los motores, ocasionando fallos imprevistos en los sistemas de aislamiento. Puesto que el talón de Aquiles en la mayoría de estos motores es el aislamiento espira-espira, éste va a ser el objeto de estudio de estas tesis. Esta problemática ha sido un calvario en el camino de los diseñadores, debido a su carácter estocástico y las incertidumbres asociadas a los diferentes modelos propuestos en la literatura. Con el desarrollo de esta tesis, se pretende modelar el fenómeno de descargas parciales, combinando los cálculos de elementos finitos con los resultados obtenidos en los ensayos de laboratorio, para predecir la aparición de descargas parciales. Asimismo, se analizará el impacto que tienen en los modelos las diferentes fuentes de incertidumbre. Estas incertidumbres constituyen una potente herramienta para los diseñadores eléctricos, ya que les marcan la estrategia a seguir en su diseño, de acuerdo a las condiciones de contorno del sistema.Programa de Doctorado en Ingeniería Eléctrica, Electrónica y Automática por la Universidad Carlos III de MadridPresidente: Armando Rodrigo Mor.- Secretario: Fernando Álvarez Gómez.- Vocal: Joaquín Granado Romer

HASTECS: Hybrid Aircraft: reSearch on Thermal and Electric Components and Systems

In 2019, transportation was the fastest growing sector, contributing to environmental degradation. Finding sustainable solutions that pollute less is a key element in solving this problem, particularly for the aviation sector, which accounts for around 2-3% of global CO2 emissions. With the advent of Covid-19, air traffic seems to have come to a fairly permanent halt, but this pandemic reinforces the need to move towards a "cleaner sky" and respect for the environment, which is the objective of the Clean Sky2 program (H2020 EU), the context in which the HASTECS project has been launched in September 2016

Design and Evaluation of High Power, High Efficiency and High Power Density Motor Drives for More Electric Aircrafts

More-electric aircraft (MEA) is an attractive concept as it can reduce carbon dioxide emission, relieve fossil-fuel consumption, improve the overall efficiency of aircraft, and reduce the operational costs. However, it poses substantial challenges in designing a high-performance motor drive system for such applications. In the report of Aircraft Technology Roadmap to 2050, the propulsion converter is required to be ultra-high efficiency, high power density, and high reliability. Though the wide band-gap devices, such as the Silicon-carbide based Metal Oxide Silicon Field Effect (SiC-MOSFET), shows better switching performance and improved high-temperature performance compared to the silicon counterparts, applying it to the MEA-related application is still challenging. The high switching speed of SiC-MOSFET reduces switching loss and enables the design of high-density converters. However, it poses intense challenges in limiting the stray inductance in the power stage. The fast switching behavior of SiC-MOSFET also challenges the design scalability by multi-chip parallel, which is essential in high-power-rating converters. Moreover, the partial discharge can happen at the lower voltage when the converter is operated at high altitude, low air-pressure conditions, which threatens the converter lifetime by the accelerated aging of the insulation system. This dissertation addresses these issues at the paper-design level, power-module level, and converter level, respectively. At the paper-design level, the proposed model-based design and optimization enables shoulder-by-shoulder performance comparison between different candidate topology and then generates optimal semiconductor design space for the selected topology. At the power-module level, this dissertation focuses on the development of an ultra-low inductance module by using a novel packaging structure that integrates the printed circuit board (PCB) with direct-bounding copper (DBC). The detailed power-loop optimization, thermal analysis, and fabrication guidance are discussed to demonstrate its performance and manufacturability. At the converter level, this dissertation provides a comprehensive design strategy to improve the performance of the laminated busbar. In the design of the busbar conduction layer, this work analyzed the impacts of each stray inductance item and then proposed a novel double-side decoupled conduction-layer structure with minimized stray inductance and improved dynamic current sharing. In the design of the insulation system of the busbar, this dissertation investigates the design strategy to ensure the busbar is free of partial discharge without sacrificing the parasitic control. Through the dissertation, a single-phase 150 kVA converter, a three-phase 450 kVA converter, and a 1.2 kV, 300 A power module are designed, fabricated, and tested to demonstrate the proposed design strategies