| 1. |
- Acquaviva, Alessandro, 1987, et al.
(author)
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Manufacturing of tooth coil winding PM machines with in-slot oil cooling
- 2020
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In: Proceedings - 2020 International Conference on Electrical Machines, ICEM 2020. - 9781728199450 ; , s. 2314-2320
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Conference paper (peer-reviewed)abstract
- This paper presents a description of the manufacturing challenges and solutions of two 50 kW radial flux inner-rotor tooth coil winding PM machines with in-slot cooling for vehicle application. The two machines are designed for different DC link voltages, 600 V and 48 V, and to achieve high efficiency and high power density. To enable this, liquid cooling is necessary. In the solution presented, the oil coolant is pushed through the stator yoke and in the slots with the intent of removing the heat close to the loss generation. The cooling channels in the slots are built during the stator potting process using a high thermally conductive potting material. The machines presented in this paper are designed for high speed operation and capable to withstand RMS current densities of 25 A/mm2 in continuous operation and 35 A/mm2 for 30 s peaks, at 6 1/min oil flow and a inlet temperature of 20oC. It is shown that stator is designed to be compatible with automated manufacturing for high volume production with a set of suggested improvements.
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| 2. |
- Diana, Michela, 1987, et al.
(author)
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High Voltage Direct Drive Generators with Multiphase Single Layer Fractional Slot Concentrated Windings
- 2020
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In: Proceedings - 2020 International Conference on Electrical Machines, ICEM 2020. - 9781728199450 ; , s. 1903-1909
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Conference paper (peer-reviewed)abstract
- This paper presents design considerations for a high voltage direct drive generator for an high voltage DC offshore wind park application. The paper investigates 3-phase and 6-phase fractional slot concentrated windings for high voltage surface mounted permanent magnet machines. The paper focuses on q=2 /5, 50 pole-pairs and q=4 /11, 55 pole-pairs machines in the single layer configuration with different number of phases. The analysis has been executed by both analytical and finite element analysis methods. The paper reports the results of the comparison in terms of torque performance, power factor and losses, aiming to demonstrate the advantages and limitations of the use of fractional slot concentrated windings single layer multiphase generators for high voltage wind turbines. It is found that single layer multiphase configurations can improve the performance of the generator in terms of torque density, torque ripple and efficiency, but the low power factor can be a limiting factor for the exploitation of this technology for high voltage high power generators for wind turbine applications. In this paper, a solution to improve the PF without sacrificing the efficiency is proposed.
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| 3. |
- Haller, Stefan, 1982-, et al.
(author)
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Multi-phase winding with in-conductor direct cooling capability for a 48V traction drive design
- 2020
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In: Proceedings - 2020 International Conference on Electrical Machines, ICEM 2020. - : IEEE. - 9781728199450 ; , s. 2118-2124
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Conference paper (peer-reviewed)abstract
- Traction drive applications demand high power density motors with a good stator cooling design. We propose a novel multi-phase winding for a 48 V traction drive design having identical preformed hollow copper conductors with in-conductor direct cooling capability. This paper studies the cooling performance of an individual conductor phase using either EGW50/50 or water as coolant. Analytical calculations and experiments are conducted on a straight conductor of the same length using 20°C water as coolant. The results are then cross verified with those from the FEM simulations to validate the simulation setup. Then a final simulation is conducted at a current of 700A and a current density of 49.5 A/mm 2 on the preformed conductor using 65 CEGW50/50 as coolant at a pressure of 140kPa. The results highlight the exceptional performance of the cooling design which enables a power dissipation of 71OW at a maximum conductor temperature rise of only 56. 9 C.
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| 4. |
- Jansson, Elisabet, et al.
(author)
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Impact of Saturation and Scaling on the Field Weakening Performance of an Interior PM Machine
- 2020
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In: Proceedings - 2020 International Conference on Electrical Machines, ICEM 2020. - 9781728199450 ; , s. 1136-1142
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Conference paper (peer-reviewed)abstract
- If magnetic saturation is neglected, powerful visual tools exist for understanding field weakening in interior permanent magnet machines (IPMs). However, saturation can severely reduce field weakening performance. This is of concern in electric vehicle propulsion, where compact machines operate short-term at high power over a wide speed range. This paper shows how finite element results, including saturation, can be interpreted in established visual tools. This aids deeper understanding of field weakening in IPMs with significant saturation. Further, scaling laws for finite element results are shown to preserve field weakening performance. This allows analysis of machine peak performance over a range of maximum currents, with varying saturation severity, while scaling ensures precise fulfilment of torque and power requirements. Ultimately, this combination of current variation and scaling can be used to identify the trade-off between inverter rating and machine volume, with finite element analysis accuracy, for any specific application and IPM geometry.
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| 5. |
- Mademlis, Georgios, 1992, et al.
(author)
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Performance Evaluation of Electrically Excited Synchronous Machine compared to PMSM for High-Power Traction Drives
- 2020
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In: Proceedings - 2020 International Conference on Electrical Machines, ICEM 2020. - 9781728199450 ; , s. 1793-1799
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Conference paper (peer-reviewed)abstract
- The electric drive design for heavy-duty vehicles ischallenging due to special requirements involved, such as highstarting torque and operation at the peak power for a longtime. The electrically excited synchronous machine (EESM) is asuitable machine type for such an application and a potentialalternative to the permanent magnet synchronous machines(PMSM) due to the superior flexibility that the control of thebrushless rotor excitation offers. The direct adjustment of theflux allows also to tune the best efficiency region of the machineclose to the usual operating points of the vehicle achieving at thesame time a better power factor compared to a PMSM, whichcan further increase the efficiency and the power capability ofthe stator inverter. A case-study comparison of a EESM- andPMSM-based drive for electric trucks is presented in this paperwhere Finite-Element-Method and Matlab simulations of thewhole vehicle drivetrain showcase the advantages of the EESM.
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| 6. |
- Sjölund, Jonathan, et al.
(author)
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End Effects and Geometric Compensation in a Linear Permanent Magnet Synchronous Generator with Buried Topology
- 2020
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In: 2020 International Conference on Electrical Machines (ICEM). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781728199450 ; , s. 455-461
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Conference paper (peer-reviewed)abstract
- Electricity production from ocean waves with different design topologies is a topic of big research interest. Many of such topologies are based on submerged linear generators which inherently introduce end forces. In this paper, the detent force is investigated for two different winding patterns using Maxwell stress tensor in a finite element software. Induced voltage is also investigated for active stator area and the unequal contributions due to stator ends. Two ways of overcoming the end forces are further investigated: The first method reduces the magnetic flux difference when the translator is surrounded by stator and air, respectively. The second aims at countering the end forces at both ends for full active stator area. The first investigated end effect compensation decreased the end effects but increased the attraction forces. The second end effect compensation decreased the end forces during full active stator area with little effect on the attraction forces.
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| 7. |
- Sugiyama, Kenta, et al.
(author)
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Generator Loss Analysis and Comparison for 5MW Wind Turbine System
- 2020
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In: Proceedings - 2020 International Conference on Electrical Machines, ICEM 2020. - 9781728199450 ; , s. 888-893
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Conference paper (peer-reviewed)abstract
- In recent years, renewable energy has attracted attention due to the issue of global warming. Offshore wind power is considered to be an important part of the future energy supply. In a previous studies, a 2level converter for a 5MW wind turbine system was analyzed [1]. It would be of substantial interest to also know how the efficiency of a 3-level converter would compare with a 2level equivalent [2]. The purpose of this paper, is to analyze and show the efficiency of a 5MW wind generating system, when operated with a 2 and 3level inverter.
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