| 1. |
- Acquaviva, Alessandro, 1987, et al.
(författare)
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Computationally Efficient Modeling of Electrical Machines With Cooling Jacket
- 2019
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Ingår i: IEEE Transactions on Transportation Electrification. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 2332-7782. ; 5:3, s. 618-629
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Tidskriftsartikel (refereegranskat)abstract
- Modeling of electrical machines is a multiphysics problem. Depending on the phenomena of interest and the computational time constraint, this can be done at different levels of detail. In this article, the main approaches to model the thermal behavior of electrical machines with a liquid cooled casing around the stator (often referred to as cooling jacket) are analyzed and a novel approach is presented. The proposed method aims at creating computationally efficient 3-D multiphysics models of electrical machines with liquid cooled jacket. This model is based on the assumption of a fully developed flow in the cooling jacket which allows to scale the computational fluid dynamics (CFD) simulation to 1-D. The slot with a two layer concentrated winding and potting material is modeled using a composite material comprising of both the conductors and slot filler. Similarly, a unified material is used to model the end-windings. Experimental results on a traction machine for vehicle applications are presented showing good agreement with the simulations. Also, a comparison with a 3-D CFD is presented to verify the pressure drop in the pipe bend. Finally, the model is used to simulate a dynamic load cycle, which would be computationally extremely demanding with combined 3-D CFD and thermal FEA of the machine and its cooling.
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| 2. |
- Acquaviva, Alessandro, 1987, et al.
(författare)
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Electromagnetic and Calorimetric Validation of a Direct Oil Cooled Tooth Coil Winding PM Machine for Traction Application
- 2020
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Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 13:13
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Tidskriftsartikel (refereegranskat)abstract
- Tooth coil winding machines offer a low cost manufacturing process, high efficiency and high power density, making these attractive for traction applications. Using direct oil cooling in combination with tooth coil windings is an effective way of reaching higher power densities compared to an external cooling jacket. In this paper, the validation of the electromagnetic design for an automotive 600 V, 50 kW tooth coil winding traction machine is presented. The design process is a combination of an analytical sizing process and FEA optimization. It is shown that removing iron in the stator yoke for cooling channels does not affect electromagnetic performance significantly. In a previous publication, the machine is shown to be thermally capable of 25 A/mm2 (105 Nm) continuously, and 35 A/mm2 (140 Nm) during a 10 s peak with 6 l/min oil cooling. In this paper, inductance, torque and back EMF are measured and compared with FEA results showing very good agreement with the numerical design. Furthermore, the efficiency of the machine is validated by direct loss measurements, using a custom built calorimetric set-up in six operating points with an agreement within 0.9 units of percent between FEA and measured results.
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| 3. |
- Alatalo, Mikael C D, 1959, et al.
(författare)
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Electric Machine Design for Traction Applications Considering Recycling Aspects- Review and New Solution
- 2011
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Ingår i: IECON Proceedings (Industrial Electronics Conference). - 2162-4704 .- 2577-1647. - 9781612849720 ; , s. 1836-1841
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Konferensbidrag (refereegranskat)abstract
- With the expansion of the fleet of electric and hybrid electric vehicles worldwide, it is of interest to consider recycling aspects of the parts that are introduced in these new vehicles. This paper focuses on the design of electrical machines considering recycling of its components. The materials to consider are mainly copper, core materials such as lamination steel or iron, and permanent magnets. One design is suggested with a core material of soft magnetic composites which is very suitable for recycling as it is a brittle material and thus simplifies the access of the copper winding. The suggested design shows to have similar performance to a similar size and similar weight commercial permanent magnet electric machine made with steel lamination. © 2011 IEEE.
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| 4. |
- Alatalo, Mikael C D, 1959, et al.
(författare)
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Evaluation of three cooling concepts for an electric vehicle motor - 3D models
- 2020
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Ingår i: Proceedings - 2020 International Conference on Electrical Machines, ICEM 2020. ; , s. 867-873
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Konferensbidrag (refereegranskat)abstract
- The aim of this paper is to model and analyze the performance of a permanent magnet electric motor for an electric vehicle with different cooling duct designs; wave-cooling duct, spiral cooling duct, and cooling in potted end regions. The comparison between designs are made first by using a 2way coupled electromagnetic model and a computational fluid dynamic (CFD) software for a set of operating points, and then by using lumped parameter models (and boundary conditions from the 2-way coupled model) to calculate the drive system performance over the motor operating region. The first task is described in this paper and the second task in an accompanying paper. It is found that the three cooling system designs give similar efficiencies and average component temperatures with some exceptions depending on the loss distribution but also that the hottest regions have different locations. However, the relatively high flow rate of 10 l/min used in the comparison, results in efficient cooling and low temperature difference between the coolant and the aluminum housing.
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| 5. |
- Franzke, Randi, 1989, et al.
(författare)
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Measurements and CFD Modeling of Temperatures in the Engine Compartment of a Hybrid Electric Vehicle
- 2018
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Ingår i: 2017 IEEE Vehicle Power and Propulsion Conference, VPPC 2017 - Proceedings. ; 2018-January
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Konferensbidrag (refereegranskat)abstract
- In this article the temperature distribution within the engine compartment of a hybrid electric vehicle is experimentally and numerically investigated. The aim of this study is to develop a simulation model that captures the thermal behaviour of the electrical components for different driving conditions. For the experimental part, temperature sensors are placed at various locations inside cooling hoses as well as on the hoses and on various components. Using the commercial computational fluid dynamics (CFD) software StarCCM+, a complete vehicle simulation is set up for the same model. A comparison between the measurements and the numerical results shows good results. The increase in cooling media temperature when passing through the CIDD (Combined Inverter and DC/DC converter) is determined with a 10\,\% deviation, also the CIDD surface temperatures are well predicted. For the Electric Rear Axle Drive (ERAD) the surface temperatures lie within the requested 5k interval for the majority of measurement points, especially on the exterior of the cooling channel around the electric machine.
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| 6. |
- Grunditz, Emma, 1980, et al.
(författare)
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Acceleration, Drive Cycle Efficiency, and Cost Tradeoffs for Scaled Electric Vehicle Drive System
- 2020
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Ingår i: IEEE Transactions on Industry Applications. - 0093-9994 .- 1939-9367. ; 56:3, s. 3020-3033
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Tidskriftsartikel (refereegranskat)abstract
- This article investigates and quantifies, for varying drive system ratings (0.5-2.0 times the rating of a small and large reference system), the tradeoff relations between the electric vehicle acceleration performance and energy consumption during a wide range of drive cycles, using detailed load-dependent loss models. Additionally, the results are related to estimated drive system cost by transparently determined scalable electric motor and inverter cost models. When reducing the system rating to half, the cost is 83% of the small reference system and 76% of the large. The acceleration time (0-100 km/h) decreases nonlinearly with increasing system rating. Interestingly, the drive cycle energy consumption generally decreases with decreasing drive system rating, and most cycles show a minimum consumption with a downscaled drive system. For the small system, the strongest impact was noted for the HWFET cycle where the energy consumption is reduced 2% when downscaling the drive system by 0.5 relative to the reference system. For the large system, NYCC shows the largest reduction in energy consumption: 4% when scaled by 1.6 relative to the reference system.
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| 7. |
- Grunditz, Emma, 1980
(författare)
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BEV Powertrain Component Sizing With Respect to Performance, Energy Consumption and Driving Patterns
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, various drive cycles, legislative, official real-world and measured withinthe frame of the project, have been studied and characterized in terms of speed and accelerationcycle parameters, as well as acceleration and speed distribution. The objective was toassess typical vehicle usage on different road types, but also to study the implication on vehicleenergy consumption due to the drive cycle’s characteristics. For this evaluation, threereference vehicles were designed after different set performance requirements, with data onexisting BEVs as a frame of reference. An available traction motor, power electronic moduleand battery cell were utilized, where the motor was scaled by active length. Finally, theconsequence of downsizing the electric drive system in terms of energy consumption andperformance was also studied.Through comparison between legislative together with official real-world cycles andmeasured drive cycles, it was found that even though the measured cycles reach higherpeak acceleration levels for a certain speed level, they still spend only slightly more time athigher levels of acceleration compared to the official cycles, at least on average over a groupof similar cycles. During the powertrain sizing regarding torque and power, it turned out thatthe acceleration requirementwas dominating over other requirements such as top speed, andgrade levels. The analysis shows that for two cycles with similar speed parameters such asmaximum and average speed and time share at low speed, but where the speed time tracesare very different with many more speed fluctuations in one cycle compared to the other,in combination with generally higher acceleration levels, the increase in net battery energyconsumption per distancemay be as high as 28% for the cycle with more speed fluctuations.By down-scaling the electric drive system of the City car by 40%, the net battery energy perdriven distance for low speed cycles increased by about 3−6%, while three of the cyclescould not be fulfilled due to limited acceleration capability.
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| 8. |
- Grunditz, Emma, 1980, et al.
(författare)
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Characterizing BEV Powertrain Energy Consumption, Efficiency, and Range During Official and Drive Cycles From Gothenburg, Sweden
- 2016
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Ingår i: IEEE Transactions on Vehicular Technology. - 0018-9545 .- 1939-9359. ; 65:6, s. 3964 - 3980
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, the energy consumption per distance of a battery electric vehicle (BEV) is comprehensively investigated for various official and gathered real-world drive cycles, including the powertrain's cycle average efficiency. The powertrain component losses are modeled with a high level of detail, and they are functions of both speed and load. It is shown that the difference in calculated drive-cycle energy consumption may be up to 16% when using two different acceleration approximation methods and one speed sample per second, which is an interval commonly used among drive cycles. In contrast to combustion engine vehicles (CEVs), BEV energy consumption per distance generally increases with increasing cycle speed levels, and time spent at high speed levels have the largest influence on the consumption. The effect of acceleration on energy consumption is seen to be considerably reduced due to regenerative braking as it reduces the consumption by up to 49% on an acceleration intense cycle. Even when the regenerative area is limited to about half, the decrease in driving range is less than 1% for most cycles. By introducing the concept of overconsumption, it is shown that much time spent at high levels of acceleration is one of the largest contributors to excess energy consumption for BEVs. Furthermore, the found cycle average powertrain efficiencies are quite similar between the different cycles, with 82%–90% during propulsion and only slightly lower during braking, i.e., much less speed dependent than for CEVs.
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| 9. |
- Grunditz, Emma, 1980
(författare)
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Design and Assessment of Battery Electric Vehicle Powertrain, with Respect to Performance, Energy Consumption and Electric Motor Thermal Capability
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, various drive cycles, legislative, official real-world and measured, have been studied and characterized based on their speed and acceleration content. Three reference vehicles (a City car, a Highway car and a Sport car) were conceptualized after performance requirements, with data on existing battery electric cars as a frame of reference. The acceleration performance, energy consumption and efficiency of the powertrain, comprising a traction motor, a power electronic module and a battery, was determined and analyzed for the various drive cycles. Furthermore, the consequence on acceleration performance, drive cycle fulfillment and energy consumption during re-scaling of the electric drive system was studied. Moreover, the electromagnetic losses for four different slot areas were compared, along with the thermal steady state and transient over load as well as temperature development during drive cycles. Through comparison between official and measured drive cycles, it was found that even though the measured cycles reach higher peak acceleration levels for a certain speed level, on an average they still spend only slightly more time at higher levels of acceleration compared to the official cycles. The resulting cycle average powertrain efficiencies were fairly similar for both the official and measured cycles, and showed to be slightly higher for cycles that spend more time at higher speed levels. During the powertrain sizing regarding torque and power, the acceleration requirement turned out to dominate over other requirements such as top speed, and grade levels. It was found that a down scaling of the electric power train resulted in an energy consumption down to 94% of the original powertrain size. The small slot geometry had the highest peak losses during the drive cycles, however, on a cycle average it had the lowest losses for many cycles. This fact, in combination with the highest peak torque and lowest material cost, makes it a very interesting option as an electric vehicle traction motor.
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| 10. |
- Grunditz, Emma, 1980, et al.
(författare)
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Drive Cycle Evaluation and Consumption of PM Motors for a Typical Battery Electric City Bus
- 2023
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Ingår i: 2023 IEEE International Conference on Electrical Systems for Aircraft, Railway, Ship Propulsion and Road Vehicles & International Transportation Electrification Conference (ESARS-ITEC). - 9798350346893
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Konferensbidrag (refereegranskat)abstract
- Four permanent magnet electric machines for a typical battery electric city bus (BECB) are compared regarding drive cycle energy consumption during 18 official and one logged bus drive cycle. Two machine types are used; an interior permanent magnet synchronous machine (IPMSM) with a two layer distributed winding (DW), and an IPMSM with tooth coil windings (TCW), both with either copper or aluminum winding material. The results are aimed for a life cycle assessment study of electric machines in a typical BECB. A conducted BECB market survey is shortly summarized, and 40 official bus drive cycles are characterized using the chosen bus dimensions.
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