عنوان
پدید آورنده
موضوع
رده
کتابخانه
محل استقرار
TLpq2498531471
انگلیسی
High Performance Permanent Magnet Machines for Transportation Applications
[Thesis]
Islam, Sariful
Mikail, Rajib
North Carolina State University
2020
181
Ph.D.
North Carolina State University
2020
The electrification in the transportation sectors such as those with electric vehicles, drones, UAV, and air-taxi is progressing at an unprecedented pace. As a result, the need for high performance (high power density and high efficiency) permanent magnet (PM) electric machines to enhance the fuel efficiency of these electrified vehicles is also significant. The current trend is to increase the operating speed range of PM machines to achieve smaller, compact, and lighter machines for the powertrain of transportation applications. But the conventional PM machines suffer from poor efficiency at higher speeds due to the frequency-dependent core loss (eddy, hysteresis), PM loss (eddy loss), and ac conductor loss. This dissertation presents the research and development of PM electric machines for the transportation sector with innovations in windings, stator and rotor topologies, and airgap flux profiling methods to achieve high power density and high efficiency. The novel windings are the space-shifted wye-delta winding, space-shifted three-layer winding, and asymmetric bar winding, whereas the novel machine topologies are 2D airgap slotless-Halbach machine and 3D airgap slotless radial-axial machine. The novel space-shifted wye-delta and three-layer fractional slot windings are proposed to cancel unwanted harmonics of the stator magnetic field to reduce the frequency-dependent losses. The design methodology of these novel windings has been demonstrated using both the analytical and finite element analysis (FEA) methods. The space-shifted wye-delta winding is based on two wye-delta windings which are displaced in space, whereas the space-shifted three-layer winding is based on two three-layer windings which are displaced in space. The FEA based analysis shows that the application of these windings in the PM machines substantially improves the efficiency through minimization of frequency-dependent losses compared to the conventional fractional slot winding. These windings are also effective in improving some other performances, such as torque ripple, noise, and vibration. Finally, the FEA results are validated experimentally. In another winding design, the asymmetric bar winding is proposed to reduce the ac conductor loss (skin effect and proximity effect) for enhancing the high-speed efficiency. This concept utilizes asymmetric bar height in a slot whereas conventional winding uses symmetric bar height. The FEA based electromagnetic and thermal results show the superiority of the proposed asymmetric bar winding compared to the conventional bar winding in terms of efficiency and power density. The first innovative machine topology is the 2D airgap slotless-Halbach machine which circumvents the need for electrical lamination in the rotor through the use of a special Halbach arrangement. Moreover, the magnetic teeth of a conventional machine are also replaced with lightweight thermal plastic. Hence, the presence of a negligible core material reduces the frequency-dependent losses and total mass of the machine. The FEA results show the superiority of this topology in terms of power density and efficiency. A comprehensive comparison of the slotless-Halbach machine with the conventional machine has been carried out to evaluate the pros and cons of this topology. Finally, a prototype slotless-Halbach machine is built and all the FEA results are validated experimentally. The second innovative machine topology is the 3D airgap slotless radial-axial flux machine which is an electromagnetic and structural integration of both the axial and radial flux machine with integrated winding. The 3D airgap machine converts the inactive structural and electromagnetic components into active components by placing magnets in the rotating end plate to further enhance the power density of a slotless machine. The idea of the 3D airgap machine is conceptualized using the 3D-FEA method. The superiority of the 3D airgap machine compared to a 2D airgap machine is also explored through extensive electromagnetic and structural analysis. The innovative windings and machine topologies explored in this dissertation pave the path towards the design and development of high-performance (high power density, high efficiency, and low torque ripple) PM machines for transportation applications.
Electrical engineering
Electromagnetics
Transportation
Islam, Sariful
Mikail, Rajib
مطالعه متن کتاب p
[Thesis]
276903
a
Y
