| 1. |
- Grauers, Anders, 1966, et al.
(author)
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Comparing fuel cells and other power trains for different vehicle applications
- 2017
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In: EVS 2017 - 30th International Electric Vehicle Symposium and Exhibition. - : Landesmesse Stuttgart GmbH.
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Conference paper (peer-reviewed)abstract
- This paper compares the total cost of ownership (TCO) for fuel cell, battery electric, range extender and biofuel combustion engine power trains. The TCO difference shows that the power trains are suitable for very different vehicle niches. Battery electric vehicles can reach the lowest cost per kilometer, but only if the battery is utilized very much. Fuel cell range extender vehicles are cost effective for vehicles requiring long driving range but typically driving shorter distances. Internal combustion engine power trains will have the lowest TCO for vehicles with short driving distance during their life, even if the biofuel is rather expensive.
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| 2. |
- Grauers, Anders, 1966, et al.
(author)
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PM generator with series compensated diode rectifier
- 2000
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In: Proceedings of the 2000 IEEE Nordic workshop on power and industrial electronics, Aalborg (Denmark). - 8789179293 ; , s. 59-63
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Conference paper (other academic/artistic)abstract
- This paper presents an investigation of a series compensated diode rectifier for permanent magnet generators. Series compensation has the advantage that the reactive power produced by the compensation follows the variations in the generator's reactive power consumption, as the generator currents change. The investigation show good performance at speeds close to rated speed, and show problems of generating high power at low speed. The investigation also shows that series compensation works well in the whole operating range of a wind turbine generator system. However, the behaviour under abnormal operating conditions remains to be studied.
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| 3. |
- Thiringer, Torbjörn, 1966, et al.
(author)
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Grid Impact of a 20 kW Variable Speed Wind Turbine
- 1999
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In: European Wind Energy Conference and Exhibition (EWEC ´99), Nice, France March 1-5, 1999.
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Conference paper (peer-reviewed)abstract
- The power quality impact of a 20 kW direct-driven variable speed wind turbine equipped with passive blade pitching has been investigated. The electrical system of the turbine consists of a 66-pole permanent magnet synchronous generator, a diode rectifier and a thyristor inverter. The turbine causes a relatively high flicker in the medium wind speed range, but small changes in the dc-link can reduce this. The voltage distortion is small while the harmonic current injection reaches 10 % at rated wind speed. The investigation also shows that the passive pitch system allows high power quality
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| 4. |
- Borén, Sven, 1971-, et al.
(author)
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Stakeholder collaboration models for public transport procurement of electric bus systems
- 2019
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In: International Journal of Sustainability Policy and Practice. - : Common Ground Research Networks. - 2325-1166 .- 2325-1182. ; 15:1, s. 19-29
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Journal article (peer-reviewed)abstract
- Earlier studies have mainly focused on technology, economy, and advantages of electric buses, and they have largely shown that electric buses could be one of the solutions for sustainable public transport. Despite this, the present procurement process for public transport in Sweden is not suitable for including support systems for electric buses. This study was aimed to find a stakeholder collaboration model that would allow electric bus systems to be more effectively included in the procurement process for public transport. The results were achieved by several multi-stakeholder collaboration seminars and meetings that included representatives from regional public transport authorities, bus operators, bus manufacturers, energy companies, municipalities, and experts involved in bus transport. The study primarily developed two stakeholder collaboration models, suggesting that charging infrastructure should be designed separately from the common procurement process. In these models, energy companies, electric grid owners, charging infrastructure operators, regional public transport authorities, and municipalities need to collaborate. The first model is designed for a system that includes chargers at certain locations along a route and/or stakeholders with a low level of experience of electric bus systems, while the second is designed for a system that includes bus charging at the depot and/or stakeholders with a high level of experience of electric bus systems.
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| 5. |
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| 6. |
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| 7. |
- Davidsson, Karin, et al.
(author)
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Safe Efficient Vehicle Solutions -On Driving Forces for Future Road Transportations
- 2011
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In: EEVC Brussels, Belgium, October 26-28, 2011.
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Conference paper (other academic/artistic)abstract
- The primary objective of this paper is to present the most relevant factors and driving forces that influence future sustainable road transportations and exemplify how they may influence the development. The research methodology used is explorative scenarios where data collected from workshops, expert panels and surveys lay the foundations for the explanatory models [1]. Several driving forces are identified. However, two of them are found to be more important for the study as they have a strong influence on the development of the road transport system; yet it is uncertain how these driving forces will develop. The first of these driving forces is the ability of the authorities to take an active role when developing a sustainable transport system and the second how actively people will demand and support changes in the vehicles and the transport system. Four different future road transportation scenarios have been created to explore how changes in these two driving forces will influence the development of vehicles and road transport system; these scenarios are explained together with characteristics of future road transportation solutions. It is concluded that plans for technology development need to consider the uncertainties of these driving forces in order to enable creation of robust development roadmaps.
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| 8. |
- Gillström, Henrik, 1989-, et al.
(author)
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A framework to describe electrification of logistics systems
- 2023
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In: Logistics Research Network Conference.
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Conference paper (other academic/artistic)abstract
- Purpose: Electrifying freight deliveries is viewed as a vital step in reducing the sector's environmental impact. However, the logistics systems are not uniform and different systems pose different challenges, thus likely to use different electrification strategies. The purpose of this paper is to develop a framework to describe how different logistic systems relate to different electrification challenges, and what type of electrification strategy is suitable for which logistics systems.Research Approach: The study uses a descriptive approach to create a framework with empirical data from two ongoing research projects through interviews, workshops, and seminars. Suitable electrification strategies for different logistics systems are determined. Findings and Originality: The proposed framework illustrates how different transport segments can be described and how the segments can be combined with charging strategies. Furthermore, by combining the segments and charging strategies, it is possible to identify suitable electrification strategies in different types of systems. Research Impact: This study takes a holistic view of logistics systems and electrification, to shed light on enablers and barriers for electrification of trucks in different types of logistics contexts. Practical Impact: The framework can build an understanding of aspects that must be considered in different systems and situations. It will help identify transport segments which are more or less suitable for electrification depending on how developed the public charging infrastructure is.
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| 9. |
- Grauers, Anders, 1966, et al.
(author)
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A user-friendly method to analyze cost effectiveness of different electric bus systems
- 2017
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In: EVS30 Symposium.
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Conference paper (peer-reviewed)abstract
- This paper is an update on a method to analyze and compare electric bus and charging systems from a totalcost perspective. The method is useful for proposing a suitable combination of bus and charger systemsdepending on the route specifications, timetables and other local conditions. In this update, a user-friendlytool which simplifies the analysis process is presented. The analysis tool enables the user to experimentallyinvestigate and quantify the trade-offs between parameters such as battery size, charging strategies andcharging infrastructure, vehicle fleet and operational costs from a total cost perspective
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| 10. |
- Grauers, Anders, 1966
(author)
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Design of Direct-driven Permanent-magnet Generators for Wind Turbines
- 1996
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Doctoral thesis (other academic/artistic)abstract
- This thesis presents an investigation of how a direct-driven wind turbine generator should be designed and how small and efficient such a generator will be. Advantages and disadvantages of various types of direct-driven wind turbine generators are discussed, and a radial-flux permanent-magnet generator connected to a forced-commutated rectifier is chosen for a detailed theoretical investigation. Further, a design method is developed for the electromagnetic part of the chosen generator type. The generator is optimized with a simplified cost function which, besides including the cost of the active generator parts and the cost of the structure, also includes the cost of the average losses. Therefore, a method to calculate the average losses is derived. The design method is used to investigate the optimization of a 500 kW generator, and the size, efficiency and active weight of optimized generators from 30 kW to 3 MW are presented. A result of the investigation is that the outer diameters of the direct-driven generators are only slightly larger than the width of conventional wind energy converter nacelles. A comparison of average efficiency shows that direct-driven generators, including the losses in the frequency converters, are more efficient than conventional wind energy converter drive trains. Compared with other direct-driven generators, the proposed generator type is small, mainly because of the forced-commutated rectifier and because the generator is not required to produce a pull-out torque higher than the rated torque.
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