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To make an all-electric aircraft possible, both high power densities and efficiencies are needed. However, particularly high demands are also placed on the thermal management system. Often, the electric motor and cooling system are considered without co-optimization. Particularly in the case of electric motors with conductors directly cooled by a liquid, there is great potential for optimization, since the temperature-dependent Joule losses determine the largest part of the losses. This publication shows the main influencing parameters for the electric motor and cooling system: coolant speed and winding temperature. In addition, the influence of the cooling system control during a flight mission is demonstrated and its potential in mass reduction is quantified. It could be shown that with a low utilized electric motor the maximum winding temperature of 130 (Formula presented.) C is beneficial, the cooling system should work in almost all operation points in its sized operation and the mass of the heat exchanger and pump is negligible compared to the mass of the electric motor and energy storage.

To make an all-electric aircraft possible, both high power densities and efficiencies are needed. However, particularly high demands are also placed on the thermal management system. Often, the electric motor and cooling system are considered without co-optimization. Particularly in the case of electric motors with conductors directly cooled by a liquid, there is great potential for optimization, since the temperature-dependent Joule losses determine the largest part of the losses. This publication shows the main influencing parameters for the electric motor and cooling system: coolant speed and winding temperature. In addition, the influence of the cooling system control during a flight mission is demonstrated and its potential in mass reduction is quantified. It could be shown that with a low utilized electric motor the maximum winding temperature of 130 (Formula presented.) C is beneficial, the cooling system should work in almost all operation points in its sized operation and the mass of the heat exchanger and pump is negligible compared to the mass of the electric motor and energy storage.

Dagens samhälle har utvecklats till ett stort globalt system där människan fått en signifikant påverkan på klimatet och miljön. För att nå målet i Parisavtalet är det många sektorer som behöver ställa om sina verksamheter till att bli hållbara. Det gäller i allra högsta grad flygsektorn som har stora utmaningar framför sig när det gäller att minska sitt klimatavtryck. En av möjligheterna för att väsentligt minska flygets klimatpåverkan är att övergå till flygplan som drivs med hjälp av batterier istället för fossila bränslen.I det här projektet undersöks om de tekniska och infrastrukturmässiga förutsättningarna finns för att elflyg ska kunna ersätta den befintliga flygtrafiken mellan Stockholm och Visby och när i tiden en sådan förändring kan ske. Litteraturstudier och intervjuer har använts för att utforska det nuvarande kunskapsläget som är relevant för elflyg inom batteriteknik, elmotorer, aerodynamik samt infrastruktur på de relevanta flygplatserna. Med den utgångspunkten har en matematisk modell använts för att studera om de rådande tekniska förutsättningarna är tillräckliga eller om förbättringar kommer krävas. Det som framkom var att det i teorin är möjligt att tillverka ett elflygplan som kan flyga hela sträckan med befintlig teknik men att utveckling av både batteriteknik och aerodynamik sannolikt kommer krävas när andra aspekter vägs in. Infrastrukturen på flygplatserna är dessutom inte anpassade för elflyg i dagsläget, vilket leder till att det i ett optimistiskt scenario kommer gå att elektrifiera flygtrafiken mellan Stockholm och Visby inom 10 år., Today's society has evolved into a large global system where people have a significant impact on the climate and the environment. To achieve the goal of the Paris Agreement, many sectors need to change their business to become sustainable. This is very much the case for the aviation sector, which has major challenges ahead when it comes to reducing its climate footprint. One of the opportunities to significantly reduce the climate impact of aviation is to switch to aircraft powered by batteries instead of fossil fuels. This project examines whether the technical and infrastructure conditions are in place for electric aircraft to replace the existing air traffic between Stockholm and Visby and when such a change can occur in time. Literature studies and interviews have been used to explore the current state of knowledge relevant to electric aviation within battery technology, electric motors, aerodynamics and infrastructure at the relevant airports. Based on this, a mathematical model has been used to study whether the current technical conditions are sufficient or if improvements will be required. What emerged was that, in theory, it is possible to produce an electric aircraft that can fly the entire distance with existing technology, but that development of both battery technology and aerodynamics is likely to be required when other aspects are taken into account. The infrastructure at the airports is also not adapted for electric flights yet, which means that in an optimistic scenario it will take up to 10 years before air traffic can be fully electrified between Stockholm and Visby.

Dagens samhälle har utvecklats till ett stort globalt system där människan fått en signifikant påverkan på klimatet och miljön. För att nå målet i Parisavtalet är det många sektorer som behöver ställa om sina verksamheter till att bli hållbara. Det gäller i allra högsta grad flygsektorn som har stora utmaningar framför sig när det gäller att minska sitt klimatavtryck. En av möjligheterna för att väsentligt minska flygets klimatpåverkan är att övergå till flygplan som drivs med hjälp av batterier istället för fossila bränslen.I det här projektet undersöks om de tekniska och infrastrukturmässiga förutsättningarna finns för att elflyg ska kunna ersätta den befintliga flygtrafiken mellan Stockholm och Visby och när i tiden en sådan förändring kan ske. Litteraturstudier och intervjuer har använts för att utforska det nuvarande kunskapsläget som är relevant för elflyg inom batteriteknik, elmotorer, aerodynamik samt infrastruktur på de relevanta flygplatserna. Med den utgångspunkten har en matematisk modell använts för att studera om de rådande tekniska förutsättningarna är tillräckliga eller om förbättringar kommer krävas. Det som framkom var att det i teorin är möjligt att tillverka ett elflygplan som kan flyga hela sträckan med befintlig teknik men att utveckling av både batteriteknik och aerodynamik sannolikt kommer krävas när andra aspekter vägs in. Infrastrukturen på flygplatserna är dessutom inte anpassade för elflyg i dagsläget, vilket leder till att det i ett optimistiskt scenario kommer gå att elektrifiera flygtrafiken mellan Stockholm och Visby inom 10 år., Today's society has evolved into a large global system where people have a significant impact on the climate and the environment. To achieve the goal of the Paris Agreement, many sectors need to change their business to become sustainable. This is very much the case for the aviation sector, which has major challenges ahead when it comes to reducing its climate footprint. One of the opportunities to significantly reduce the climate impact of aviation is to switch to aircraft powered by batteries instead of fossil fuels. This project examines whether the technical and infrastructure conditions are in place for electric aircraft to replace the existing air traffic between Stockholm and Visby and when such a change can occur in time. Literature studies and interviews have been used to explore the current state of knowledge relevant to electric aviation within battery technology, electric motors, aerodynamics and infrastructure at the relevant airports. Based on this, a mathematical model has been used to study whether the current technical conditions are sufficient or if improvements will be required. What emerged was that, in theory, it is possible to produce an electric aircraft that can fly the entire distance with existing technology, but that development of both battery technology and aerodynamics is likely to be required when other aspects are taken into account. The infrastructure at the airports is also not adapted for electric flights yet, which means that in an optimistic scenario it will take up to 10 years before air traffic can be fully electrified between Stockholm and Visby.

The demand for alternative fueling methods to reduce the need for fossil fuels is not limited to the electrification of ground vehicles. More-electric and all-electric aircraft pose challenges, with extensive requirements in terms of power density, efficiency, safety, and environmental sustainability. This paper focuses on electrical machines and their components, especially for high-power applications like the main propulsion. The electrical machine is evaluated from different aspects, followed by a closer look at the components and materials to determine the suitability of the current standard materials and advanced technologies. Furthermore, the mechanical and thermal aspects are reviewed, including new and innovative concepts for the cooling of windings and for the use of additive manufacturing. Aircraft have special demands regarding weight and installation space. Following recent developments and looking ahead to the future, the need and the possibilities for light and efficient electrical machines are addressed. All of the approaches and developments presented lead to a better understanding of the challenges to be expected and highlight the upcoming opportunities in electrical machine design for the use of electric motors and generators in future aircraft. Several prototypes of electrical machines for smaller aircraft already exist, such as the electric drive of the Siemens powered Extra 330LE. The focus of this paper is to provide an overview of current technical possibilities and technical interrelations of high performance electric drives for aviation. A 1 MW drive is exemplified to present the possibilities for future drives for airplanes carrying a larger number of passengers. All presented techniques can also be applied to other drive power classes.

This paper describes the integrated modeling of a permanent magnet (PM) motor used in an electromechanical actuator (EMA). A nonlinear, lumped-element motor electric model is detailed. The parameters, including nonlinear inductance, rotor flux linkage, and thermal resistances, and capacitances, are tuned using FEM models of a real, commercial motor. The field-oriented control (FOC) scheme and the lumped-element thermal model are also described., Presented at the Power Systems Conference, 10PSC-0110, held in Fort Worth, TX, 2010. Prepared in cooperation with University of Dayton Research Institute.

The development of electromechanical actuators (EMAs) is the key technology to build an all-electric aircraft. One of the greatest hurdles to replacing all hydraulic actuators on an aircraft with EMAs is the acquisition, transport and rejection of waste heat generated within the EMAs. The absence of hydraulic fluids removes an attractive and effective means of acquiring and transporting the heat. To address thermal management under limited cooling options, accurate spatial and temporal information on heat generation must be obtained and carefully monitored. In military aircraft, the heat loads of EMAs are highly transient and localized. Consequently, a FEA-based thermal model should have high spatial and temporal resolution. This requires tremendous calculation resources if a whole flight mission simulation is needed. A lumped node thermal network is therefore needed which can correctly identify the hot spot locations and can perform the calculations in a much shorter time. The challenge in forming an accurate lumped node thermal network is to determine all the suitable thermal resistances and capacitances of the thermal network. In this paper we present an FEA-based lumped node network and its simulation of a mission profile. This model is based on a detailed FEA model to locate the hot spots, to determine the network parameters and to verify its effectiveness. The model can also deal with the nonlinear behavior of the EMA system introduced by phase-change materials (PCM) if thermal energy storage is needed, and temperature-dependent magnetic properties. This model can also be incorporated into lumped node magnetic and electric model to develop a full multi-physics, multi-scale simulation engine. This engine can accurately analyze the complete EMA system in a systematic scale and whole-mission duration., Submitted to the Proceedings of the Society of Automotive Engineers Power Systems Conference, held in Forth Worth, TX on 2-4 Nov 2010. Prepared in collaboration with Mechanical Energy Conversion Branch, Air Force Research Laboratory, Wright-Patterson Air Force Base, OH and the University of Dayton Research Institute, Dayton, OH.