scholarly journals Slot Design Optimization for Copper Losses Reduction in Electric Machines for High Speed Applications

2020 ◽  
Vol 10 (21) ◽  
pp. 7425
Author(s):  
Claudio Bianchini ◽  
Mattia Vogni ◽  
Ambra Torreggiani ◽  
Stefano Nuzzo ◽  
Davide Barater ◽  
...  
Keyword(s):  
High Speed ◽  
Hybrid Electric Vehicles ◽  
Electric Machines ◽  
Proximity Effects ◽  
Stator Windings ◽  
Tooth Width ◽  
Slot Opening ◽  
Additional Losses ◽  
Copper Losses ◽  
Wide Operating

The need of a wide operating range and a high power density in electric machines for full- and hybrid electric vehicles in traction applications has led to an increase in the operating frequency of the machine. When the electric frequency increases, the additional losses in stator windings become an issue and they have to be taken into account in the design of the electric machine. This issue is more critical when hairpin windings are employed, due to the the skin and proximity effects which produce increased copper losses. In this paper, the relationships between different stator slot parameters (tooth width, slot opening, etc.) and stator winding copper losses have been analysed in order to identify an optimal design of a single stator slot.

On the dynamic stability of high-speed gas bearings: stability study and experimental validation

2011 ◽  
Vol 2 (2) ◽  
pp. 342-351
Author(s):  
T. Waumans ◽  
J. Peirs ◽  
J. Reynaerts ◽  
F. Al-Bender
Keyword(s):  
Dynamic Stability ◽  
Stability Problem ◽  
High Speed ◽  
Experimental Validation ◽  
Stability Study ◽  
Gas Bearings ◽  
Aerostatic Bearings ◽  
Bearing Dynamics ◽  
Wide Operating ◽  
Operating Temperature Range

For high-speed applications, gas lubricated bearings offer very specific advantages over other,more conventional bearing technologies: a clean and oil-free solution, virtually wear-free operation, lowfrictional losses, wide operating temperature range, etc. However, the principal drawback involved in theapplication of high-speed gas bearings concerns the dynamic stability problem. Successful applicationtherefore requires control of the rotor-bearing dynamics so as to avoid instabilities.After a detailed study of the dynamic stability problem and the formulation of a convenient stability criterium,a brief overview is given of the currently existing bearing types and configurations for improving the stability.In addition, three strategies are introduced: (i) optimal design of plain aerostatic bearings; (ii) modification ofthe bearing geometry to counteract the destabilising effects in the gas film; and (iii) introduction of dampingexternal to the gas film as to compensate for the destabilising effects.These strategies are worked out into detail leading to the formulation of a series of design rules. Theireffectiveness is validated experimentally at a miniature scale. In recent experiments a rotational speed of1.2 million rpm has been achieved with a 6 mm rotor on aerodynamic journal bearings, leading to a recordDN-number of 7.2 million.

Use of High-Temperature Superconductors in High Speed Electronic Switches with Current Gain

1987 ◽  
Vol 99 ◽  
Author(s):  
Bryan A. Biegel ◽  
R. Singh
Keyword(s):  
High Temperature ◽  
Josephson Junction ◽  
Resonant Tunneling ◽  
High Speed ◽  
High Temperature Superconductors ◽  
Semiconductor Devices ◽  
Proximity Effects ◽  
Current Gain ◽  
Recent Developments ◽  
Electronic Switches

ABSTRACTRecent developments in superconductivity have taken 77 K superconducting electronics from a dream to a likelihood. Rather than following the conventional path by developing Josephson junction-based devices, this paper discusses the unique possibilities of hybrid superconductor/semiconductor devices. The two devices discussed are a true three-terminal hybrid resonant tunneling transistor and the semiconductor-coupled Josephson junction. Also, a list is given of as yet uninvestigated issues concerning the new superconductors and their proximity effects with semiconductors -issues that are critical to the operation of these hybrid superconductor/semiconductor devices.

scholarly journals Complex design of multi-machine electromechanical system of wind generators

2020 ◽  
pp. 66-71
Author(s):  
О. Popovych ◽  
L. Listovshchyk ◽  
А. Kribaa
Keyword(s):  
Output Power ◽  
Power Distribution ◽  
Resource Conservation ◽  
Electric Machines ◽  
Wind Power Plant ◽  
Mechanical Parameters ◽  
Stator Windings ◽  
Wind Generators ◽  
Energy Flows ◽  
Complex Design

The direction of modernization of the wind power plant is substantiated, which is aimed at a comprehensive increase in energy efficiency and resource conservation. Taking into account the reasons for the destruction of the teeth of the gear, a constructive scheme of a single-stage gearbox with several output shafts is proposed. This scheme allows you to distribute the output power to several electric machines, which, in turn, reduces the mechanical stress in the area of contact of the teeth of the gears and gears of the output shafts. Due to the division of the output power into several machines, the mass and dimensions of the gearbox are also reduced. The uniformity of power distribution on the shafts can be violated by the discrepancy between the parameters of gears, electromagnetic and mechanical parameters of electric machines. In the proposed design scheme, the uniformity of energy flows along the shafts is ensured by a sequential connection of the phases of the stator windings of electric generators.

Cogging Torque Analysis of Novel Dual-Rotor Axial Field Flux-Switching Permanent Magnet Machine

2013 ◽  
Vol 416-417 ◽  
pp. 276-280 ◽  
Author(s):  
Li Hao ◽  
Ming Yao Lin ◽  
Da Xu ◽  
Xing He Fu ◽  
Wei Zhang
Keyword(s):  
Permanent Magnet ◽  
Design Parameters ◽  
Original Design ◽  
Axial Field ◽  
Cogging Torque ◽  
Tooth Width ◽  
Rotor Pole ◽  
Torque Analysis ◽  
Slot Opening ◽  
3D Finite Element Method

The cogging torque of a novel dual-rotor axial field flux-switching permanent magnet (DRAFFSPM) machine is investigated in this paper. The analytical equation of the DRAFFSPM machine is deduced. Based on 3D finite element method, the influences of the design parameters on the cogging torque are analyzed. The H-shaped stator tooth with slot chamfer is proposed and the slot opening width and chamfer thickness are optimized to reduce the cogging torque. It shows that the cogging torque is the minimum when the stator tooth width and stator magnet width equal to 8o and 7.5o mech., respectively. The cogging torque can be reduced by ~64% when the rotor pole width is 1.6 times that of the original design. The cogging torque can be reduced by ~80% when the chamfer is added in the stator slot.

Bending Fatigue Tests of High Speed Spur Gears

1981 ◽  
Vol 103 (2) ◽  
pp. 466-473 ◽  
Author(s):  
I. Yuruzume ◽  
H. Mizutani
Keyword(s):  
High Speed ◽  
Normal Load ◽  
Load Capacity ◽  
Spur Gear ◽  
Fatigue Tests ◽  
Spur Gears ◽  
Bending Fatigue ◽  
Tooth Width ◽  
Bending Load ◽  
Bending Fatigue Strength

Effects of addendum modification of tooth profiles on the bending fatigue strength of high speed spur gear are discussed in this presentation: A JIS Class O Spur gear of m3, α20 deg, Z1 27, and made of AMS 6260 (AISI 9310) steel precisely ground after carburizing and hardening was meshed with the other gear of Z2 77 and operated at 8550 rpm. In this running test, bending load capacity and running performance comparisons between the gear with standard tooth profile and the two shifted gears of which tooth addendum modification coefficients were 0.35 and 0.8. The maximum normal load of the gear with addendum modification coefficient 0.8 at 107 (10 million) cycles was 1.8 kNsmm per unit tooth width. The maximum Hertz stress of this gear was 2.43 × 109 Nsm2. The allowable normal load of the gear with 0.8 was higher than that of the standard gear by 87 percent and higher than of the 0.35 profile shifted gears by 20 percent.

scholarly journals Series Architecture on Hybrid Electric Vehicles: A Review

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7672
Author(s):  
Alessandro Benevieri ◽  
Lorenzo Carbone ◽  
Simone Cosso ◽  
Krishneel Kumar ◽  
Mario Marchesoni ◽  
...  
Keyword(s):  
Hybrid Electric Vehicles ◽  
New Technologies ◽  
Combustion Engine ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Wide Bandgap ◽  
Parallel Architectures ◽  
Medium Size ◽  
Power Electronic Converters ◽  
Additional Losses

The use of series architecture nowadays is mainly on hybrid buses. In comparison with series-parallel and parallel architectures, which are usually exploited on medium-size cars, the series architecture allows achieving internal combustion engine higher efficiency. The downside of this architecture, due to a double energy conversion (i.e., mechanical energy converted in electrical energy and electrical energy converted again in mechanical energy), is that additional losses are introduced. For this reason, the parallel and the series/parallel architectures were considered more suitable for hybrid medium-size cars. Nevertheless, the use of new technologies can change this scenario. Regarding storage systems, supercapacitors achieved a significant energy density, and they guarantee much higher efficiency than battery storage. Moreover, the use of wide-bandgap components for power electronic converters, such as silicon carbide devices, assure lower losses. In this scenario, the series architecture can become competitive on medium-size cars. This paper shows a review of various studies performed on this topic.

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