这是我们在2017年为美国伊利诺伊大学的学妹做的一篇美国 EE literature review 代写的范文。开篇介绍文章的相关背景---随着力学和工业的发展，电动机的效率正在成为转子越来越重要的参数。近来，永磁电机（PMM）取代了传统的感应电机，具有高效率，高稳定性，低成本和低功耗的特点。 而这篇美国 EE literature review 代写范文回顾前人的研究，对永磁电机提出新的问题。
With development of mechanics and industry, the efficiency of electric drives is becoming a more and more significant parameter for rotors. Recently, permanent magnet machines (PMM) took the place of traditional induction machines for their high efficiency, stability, low cost, and low consumption . After the invention of rare earth magnetic materials such as samarium and cobalt, the application of PMM have been largely extended as these rare earth magnetic effectively improve the performance of the PMM. Due to the development of permanent magnet (PM) material research and the development of power electronic devices, PMMs became popular in the related industry and promising in many applications such as automotive, airplane, and generators.
PMM has several different topologies. One of the most common construction is locating the permanent magnets on the surface of the rotor, which is also called surface magnet motor. In this kind of machine, the magnets are magnetized radially. Some magnets such as rare-earth magnets has low permeability, making equal inductances in a different direction. This facilitates the design of the motor and a low-cost, and simple construction can be easily realized by attaching the magnets to the surface of the rotor. Another construction is embedding the permanent magnets in the slots of the rotor, which is also called embedded magnet motor . There are several methods to construct a surface or an embedded permanent magnet motor, which leads to different topologies, including surface mounted magnets, surface magnets with pole shoes, buried tangential magnets, buried radial magnets, and inset rotor with surface magnets . A PMM with different topologies have their own advantages and disadvantages. A surface PMM has the advantage of simplification and low cost for fabrication while an embedded PMM usually has a bigger inductance in the q axis than in that in the d axis.
A PMM may have various winding structures such as distributed windings, single layer concentrated windings, and double layer concentrated windings . With the increasing demand for automated manufacturing, concentrated winding structures have gradually replaced sinusoidally distributed winding structures for their simplification and short windings in smaller motors . While in larger motors, sinusoidally distributed winding structures are preferred as they can provide high efficiency and smooth torque. To overcome the disadvantage of concentrated winding structures, the torque ripple and the winding factor of the structure should be improved. For the concentrated winding structures, the copper volume and copper losses can be effectively reduced compared to regularly distributed slots . The double layer concentrated winding structures have the smallest end windings and the Joule losses can be reduced as it has shorter end turns. However, concentrated winding structures also have some disadvantages.
以上便是EssayPhD论文代写团队中的EE 大神代写的 literature review范文。本文是IEEE格式，全文4000 words。由于篇幅以及隐私问题，我们只节选一小部分进行展示。需要EE literature review代写欢迎联系我们。