The fractional slot concentrated winding structure effectively solves the difficulty of low-speed and high-torque permanent magnet (PM) machines with a large number of poles and slots, but it also brings a wealth of magnetomotive force (MMF) harmonic. The winding function method is used to compare and analyze the stator MMF distribution and harmonic content of the fractional slot PM machines with different pole and slot combinations, and the cogging torque waveform and torque ripple are calculated by the finite element method. The influence of pole and slot combination on radial force and vibration modes of fractional slot PM machines is studied. The main vibration mode can be determined from the lowest order of radial force harmonics. The results show that in a fractional slot PM motor, the radial force is the main cause of noise and vibration, rather than the cogging torque and torque ripple. The dominant radial force is mainly produced by the interaction of rotor field harmonics and armature reaction field harmonics, and the vibration and noise will significantly increase with the decrease of the dominant vibration mode order, which largely depends on the pole and slot combination. This paper provides a certain reference for the selection of pole and slot combination in the electromagnetic design process of low speed high torque fractional slot PM motors. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

中文翻译：

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极槽组合对分数槽永磁电机转矩特性和径向力的影响

分数槽集中绕组结构有效地解决了低速大扭矩永磁（PM）电机的极数和槽数多的难题，同时也带来了丰富的磁动势（MMF）谐波。采用绕组函数法比较分析不同极槽组合的分数槽永磁电机的定子MMF分布和谐波含量，并采用有限元法计算齿槽转矩波形和转矩脉动。研究了极槽组合对分数槽永磁电机径向力和振动模式的影响。主振动模式可以从径向力谐波的最低阶确定。结果表明，在分数槽永磁电机中，径向力是噪声和振动的主要原因，而不是齿槽转矩和转矩脉动。主导径向力主要由转子场谐波和电枢反作用场谐波相互作用产生，随着主导振动模态阶次的降低，振动和噪声会显着增加，这在很大程度上取决于极槽组合。本文为低速大扭矩分数槽永磁电机电磁设计过程中极槽组合的选择提供了一定的参考。© 2021 日本电气工程师学会。由 Wiley Periodicals LLC 出版。并且随着主导振动模态阶次的降低，振动和噪声会显着增加，这在很大程度上取决于极槽组合。本文为低速大扭矩分数槽永磁电机电磁设计过程中极槽组合的选择提供了一定的参考。© 2021 日本电气工程师学会。由 Wiley Periodicals LLC 出版。并且随着主导振动模态阶次的降低，振动和噪声会显着增加，这在很大程度上取决于极槽组合。本文为低速大扭矩分数槽永磁电机电磁设计过程中极槽组合的选择提供了一定的参考。© 2021 日本电气工程师学会。由 Wiley Periodicals LLC 出版。