| 1. |
- Lindahl, Göran, et al.
(författare)
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Stavanger : Innerstaden - Utvecklingshistoria och Utvecklingsmöjligheter
- 1972
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Rapport (populärvet., debatt m.m.)abstract
- Föreliggande arbete bör inte uppfattas som något slags generalplan eller dispositionsplan utan snarare som en presentation av ett synsätt, som konkretiserats på ett antal fritt valda områden. Framställningen har två tyngdpunkter. Stort intresse har ägnats det historiska perspektivet. Syftet har varit att besvara frågan: Varför ser Stavanger ut som det gör? Varför skiljer sig denna stad så mycket från jämförbara orter i Sverige? De svar som ges för över till bokens huvudtema, frågan hur den befintliga bebyggelsen skall användas i framtiden. Bakom ligger en grundsyn som uppfattar rivning och nybyggande som åtgärder i sista hand, underhåll, upprustning och ombyggnad som det normala, något som kan sträckas ut generation eftel" generation.
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| 2. |
- Lindahl, Göran, et al.
(författare)
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Bergslagen : Arbetsplatser och bostäder under hundra år
- 1983
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Rapport (populärvet., debatt m.m.)abstract
- Denna skrift utgör resultatet av Arkitekturskolans studier läsåret 1978-79. Att redigera manuskripten visade sig arbetskrävande och har också dragit ut på tiden. Att vissa av de uppgifter som lämnas inte är helt aktuella spelar ändå inte så stor roll - tyngdpunkten i framställningen ligger på det historiska materialet och de långa tidsperspektiven.Arbetet inleds med en demografisk översikt över ett brett bälte tvärs över Mellansverige från Värmland till Upplandskusten. Där antyds utvecklingens huvudriktning både i Bergslagens gamla kärnområden och i yttre zoner av delvis annan karaktär. Därefter följer åtta från varandra fristående kapitel som dock alla har ett gemensamt mål, att granska och analysera bebyggelseu.tvecklingen inom ett tydligt avgränsat område. Konkretion och åskådlighet har eftersträvats - därför har också stor möda nedlagts på bildmaterialet i form av kartor, ritningar och foton. Valet av undersökningsobjekt har gjorts av författarna själva, som också utformat sina avsnitt självständigt.
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| 3. |
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| 4. |
- Austrin, L., et al.
(författare)
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A modeling approach of a magnetic amplifier
- 2004
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Ingår i: Journal of Magnetism and Magnetic Materials. - : Elsevier BV. - 0304-8853 .- 1873-4766. ; 272, s. E1709-E1710
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Tidskriftsartikel (refereegranskat)abstract
- New soft magnetic materials made possible the use of the magnetic amplifier technology in designing competitive electric power supplies. This technology is used in the Swedish. fighter aircraft Gripen, being also attractive for future more electrical aircraft systems due to the possibility to achieve a compact and robust design. A modeling approach of a magnetic amplifier based on the magnetic hysteresis of the core material is presented here for a common amorphous magnetic alloy.
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| 5. |
- Austrin, Lars, et al.
(författare)
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A new high power density generation system
- 2006
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Ingår i: ICAS-Secretariat, 25th Congress of the International Council of the Aeronautical Sciences 2006. - 9781604232271 ; , s. 3600-3604
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Konferensbidrag (refereegranskat)abstract
- A trend of increased Electric Power in Aircraft stresses the need of robust, low weight systems with low losses. New hard and soft magnetic materials have made it feasible to work with high speed and high frequency. Applications of new soft magnetic materials and hard magnetic materials like NeFeB magnets have enabled high density power generation systems. A new concept comprising a high speed PM-generator system and a magnetic amplifier control is presented. Magnetic amplifiers are used in the power supply of the Electronic Flight Control System in the Swedish "Gripen" fighter-aircraft. This technology is attractive in More Electric Aircraft (MEA) systems due to the possibility to achieve a compact, robust and a highly reliable system with low losses. Applications of new soft magnetic materials, such as amorphous magnetic alloys, have enabled the use of magnetic amplifier (magamp) technology in the design of competitive electric power converters. This paper presents a studied design on a 20-40 kW generator system including a +/- 270V controlled output, performed by magnetic amplifier technology. This work addresses the power generator, and the power converter. High speed PM-generators are offering high power density. The impact of operating a generation system with higher frequency and an increasing number of poles as well as the advantages with new soft magnetic materials is studied. The iron losses and the copper losses are analyzed for the generator, and the power converter.
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| 6. |
- Austrin, L., et al.
(författare)
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Evaluation of switching losses in magnetic amplifiers as an alternative to IGBT switching technologies
- 2008
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Ingår i: International Conference on Power Electronics, Machines and Drives. - : IEE. - 9780863419003 ; , s. 250-254
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Konferensbidrag (refereegranskat)abstract
- In future more electric aircraft (MEA) applications increased requirements of power levels stress the importance of low losses in converters and switching elements. In this work the losses of transistor switches are analysed and compared with the losses in magnetic amplifiers (Magamp) where amorphous alloy properties allows design of competitive devices. More Electric Aircraft technology can take advantage of this to accomplish compact, robust and reliable systems with low losses. Magamps are already used in the power supply of the Electronic Flight Control System in the Swedish "Gripen" fighter-aircraft. This paper presents a comparison between Magamp technology and an alternative Insulated Gate Bi-polar Transistor (IGBT) design. The study is concentrated on the power losses in a proposed 10 kW converter with ± 270 VDC (540 VDC) regulated output, where the fundamental difference between the switching elements is that the magnetic switch handles AC and the IGBT handles DC. To allow comparison, the copper and magnetic losses in the magnetic switch of the magnetic amplifier are considered as equivalent to the switching and conduction losses in the IGBT. The comparison is based on the sum of losses in power converters comprising six switching elements.
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| 7. |
- Austrin, Lars, et al.
(författare)
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Modeling of a Three-phase Magnetic Amplifier
- 2004
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Ingår i: Proceedings of the 24th Congress of the International Council of the Aeronatical Science, Yokohama, Japan.
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Konferensbidrag (refereegranskat)
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| 8. |
- Austrin, Lars
(författare)
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On magnetic amplifiers in aircraft applications
- 2007
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the process of designing an electric power supply system for an aircraft, parameters like low weight and low losses are important. Reliability, robustness and low cost are other important factors. In the Saab Gripen aircraft, the design of the primary power supply of the electric flight control system was updated by exchanging a switching transistor regulator to a magnetic amplifier (magamp). By introducing a magamp design, weight was saved and a more reliable power supply system at a lower cost was achieved. In this particular case, with the power supply of the electric flight control system in the Saab Gripen fighter, advantage could be taken of a specific permanent magnet generator (PM-generator). The frequency of the generator offered the perfect conditions for a magamp controller. A key parameter in designing magnetic amplifiers (magamps) is low losses. New amorphous alloys offer new possibilities of the technique in designing magnetic amplifiers, because of their extremely low losses. The core losses are evaluated by studying the equations and diagrams specifying the power losses. The core losses are evaluated and compared with the copper losses in the process of optimizing low weight and low losses. For this an engineering tool is developed and demonstrated. Evaluations of the hysteresis characteristics for the magnetic alloys, as well as modeling and simulation of the core losses, are presented in this work. The modeling of the core losses includes hysteresis losses, eddy current losses and excess losses as well as copper losses. The losses are studied dynamically during realistic operational conditions. The model can be used for any generic analysis of hysteresis in magnetic circuits. Applications of magnetic amplifiers in aircrafts have been demonstrated to be a feasible alternative
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| 9. |
- Austrin, L., et al.
(författare)
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Simulation of a magnetic amplifier circuit including hysteresis
- 2005
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Konferensbidrag (refereegranskat)abstract
- The purpose of this paper is to demonstrate the feasibility. of using a dynamic hysteresis model in simulating a magnetic amplifier (mag amp). The presented model includes static hysteresis, classical eddy currents, and excess losses. The proposed modeling approach is shown to be a feasible tool for designing mag amps.
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| 10. |
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