More electric aircraft (MEA) architectures consist of several subsystems, which must all comply with the settled safety requirements of aerospace applications. Thus, achieving reliability and fault-tolerance represents the main cornerstone when classifying different solutions. Hybrid electric aircraft (HEA) extends the MEA concept by electrifying the propulsive power as well as the auxiliary power, and thereby pushing the limits of electrification. This paper gives an overview of the high-power electrical machine families and their associated power electronic converter (PEC) interfaces that are currently competing for aircraft power conversion systems. Various functionalities and starter-generator (S/G) solutions are also covered. In order to highlight the latest advancements, the efficiency of the world's most powerful aerospace generator (Mark 1) developed within the E-Fan X HEA project is graphically represented and assessed against other rivaling solutions. Motivated by the strict requirements on efficiency, power density, trustworthiness, as well as starting functionalities, supplementary considerations on the system-level design are paramount. In order to highlight the MEA goals and take advantage of all potential benefits, all subsystems must be treated as a whole. It is then shown that the combination of PECs, aircraft grid and electrical machines can be better adapted to benefit the overall system. This survey outlines the influence of these concerns and offers a view of the future technology outlook, as well as covering the present challenges and opportunities.
Analytical modeling of electrical machines has the advantage of remarkable computational efficiency when compared with finite element analysis (FEA). This is especially important for slotless topologies, as they are well suited for 2-D analytical field solutions. Nevertheless, the analytical techniques are doubtlessly non-trivial; besides, the ill-conditioned nature of the problem comes along with the mathematical complexity. The numerical issues are shown to be loosely assessed or even ignored in some parts of the literature, which causes a lack of replicability and low practical usability of analytical approaches. Although researchers often adopt a numerically optimized formulation in their works, the mathematical manipulations that make the solutions to be well-posed and efficiently exploitable are often hidden from the reader since the focus is rather on the theoretical derivation and the exact solutions. This paper shows how the direct field solution of the magnetic field problem, named the raw field formulation (RFF), can lead to significant errors throughout the domain of slotless SPM machines, which vary significantly with the machine geometry. Then, an approach to reach the numerically optimal form of the field solution, named optimized field formulation (OFF), is proposed, comprehensibly described, and discussed. Finally, the closed-form expression and the optimal pre-conditioner underneath are explicitly presented and shown to outperform the accuracy of other pre-conditioned formulations used in the literature (including RFF). The OFF's performance is significant, especially at higher harmonic orders.INDEX TERMS Analytical solutions, numerical precision, permanent magnet machines, slotless machines.Nomenclature VOLUME 4, 2016
The use of slotless Permanent Magnet machines is becoming the first choice among many other conventional solutions when improved features, such as smooth control and very high speed, are needed. However, it is not often mentioned that in order to take advantage of the main peculiarities of this kind of machines, the whole electric drive system should be conveniently designed to avoid an unexpected decline in performance during the operation. Whenever the behavior of a motor needs to be studied by means of Finite Element Analysis (FEA) as a verification of a design process, the under-load condition is typically simulated by assuming ideal current waveforms as coil sources i.e. sinusoidal for Synchronous machines and quasi-squared for Brush-less DC (BLDC) machines. However the characteristic low inductance of slotless machine can lead to high current ripple and hence, torque ripple, if the supply system is not consequently designed. This work aims to define a framework capable of giving some useful information regarding the electric drive performance. Such a framework is based on a model representing the electric drive system which gives, indirectly, the supply current to a Finite Element (FE) motor model, in order to carry out a harmonic losses analysis based on a temporal discretization technique. A slotless motor prototype has been considered as an example and different solutions for the current ripple reduction are also discussed.
<div>Safety-critical power conversion systems play a major role in the paradigm shift towards more electric aircraft (MEA) architectures. This paper reviews the electrical machines and their power electronic systems that are currently competing in the application of integrated starter-generators (S/Gs) in MEA power systems. Motivated by the strict requirements of sufficient electrical starting capability, super-high power density and ultra-high reliability, additional considerations on the overall system design are necessary, including the power electronic converters (PECs) and integrated thermal designs. These aspects are discussed not only in the light of their many benefits but also of the challenges introduced by the continuous advancements and emerging innovations in the power conversion technology. In achieving the MEA goals and capitalize on all potential benefits, optimization-based design approaches will be necessary, where the aggregation of electric machines, PECs and the aircraft grid is considered as an integrated system to be optimized. This review highlights the importance of these aspects and offers a view on future perspectives and open issues.</div>
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.